US20030142220A1

US20030142220A1 - Method of image enhancement

Info

Publication number: US20030142220A1
Application number: US10/322,453
Authority: US
Inventors: Kia Silverbrook
Original assignee: Silverbrook Research Pty Ltd
Current assignee: Silverbrook Research Pty Ltd
Priority date: 1997-07-15
Filing date: 2002-12-19
Publication date: 2003-07-31
Also published as: US6727951B1; AUPO799997A0

Abstract

An image 2 from a digital camera is modified by employing the output from an auto exposure setting stage 1 in an image processing step 3 to provide an enhanced processed image 4 as a function of said output.

Description

Continuation Application Of U.S. Ser. No. 09/112,743 filed on Jul. 10, 1998[0001]

CROSS REFERENCES TO RELATED APPLICATIONS

The following patent applications are hereby incorporated by cross-reference. For the purposes of location and identification, US patent applications identified by their US patent application serial numbers (USSN) and US patents identified by their Patent Numbers are listed with Australian applications from which the US patents or patent applications claim the right of priority and the Applicant's Docket No.



CROSS-REFERENCED	U.S. PATENT/
AUSTRALIAN	PATENT APPLICATION
PROVISIONAL	(CLAIMING RIGHT OF
PATENT	PRIORITY FROM AUSTRALIAN	DOCKET
APPLICATION NO.	PROVISIONAL APPLICATION)	NO.

PO7991	09/113,060	ART01
PO8505	09/113,070	ART02
PO7988	09/113,073	ART03
PO9395	6,322,181	ART04
PO8017	09/112,747	ART06
PO8014	09/112,776	ART07
PO8025	09/112,750	ART08
PO8032	09/112,746	ART09
PO7999	09/112,743	ART10
PO7998	09/112,742	ART11
PO8031	09/112,741	ART12
PO8030	6,196,541	ART13
PO7997	6,195,150	ART15
PO7979	09/113,053	ART16
PO8015	09/112,738	ART17
PO7978	09/113,067	ART18
PO7982	09/113,063	ART19
PO7989	09/113,069	ART20
PO8019	09/112,744	ART21
PO7980	6,356,715	ART22
PO8018	09/112,777	ART24
PO7938	09/113,224	ART25
PO8016	6,366,693	ART26
PO8024	09/112,805	ART27
PO7940	09/113,072	ART28
PO7939	09/112,785	ART29
PO8501	6,137,500	ART30
PO8500	09/112,796	ART31
PO7987	09/113,071	ART32
PO8022	09/112,824	ART33
PO8497	09/113,090	ART34
PO8020	09/112,823	ART38
PO8023	09/113,222	ART39
PO8504	09/112,786	ART42
PO8000	09/113,051	ART43
PO7977	09/112,782	ART44
PO7934	09/113,056	ART45
PO7990	09/113,059	ART46
PO8499	09/113,091	ART47
PO8502	09/112,753	ART48
PO7981	6,317,192	ART50
PO7986	09/113,057	ART51
PO7983	09/113,054	ART52
PO8026	09/112,752	ART53
PO8027	09/112,759	ART54
PO8028	09/112,757	ART56
PO9394	09/112,758	ART57
PO9396	09/113,107	ART58
PO9397	6,271,931	ART59
PO9398	6,353,772	ART60
PO9399	6,106,147	ART61
PO9400	09/112,790	ART62
PO9401	6,304,291	ART63
PO9402	09/112,788	ART64
PO9403	6,305,770	ART65
PO9405	6,289,262	ART66
PP0959	6,315,200	ART68
PP1397	6,217,165	ART69
PP2370	09/112,781	DOT01
PP2371	09/113,052	DOT02
PO8003	09/112,834	Fluid01
PO8005	09/113,103	Fluid02
PO9404	09/113,101	Fluid03
PO8066	6,227,652	IJ01
PO8072	6,213,588	IJ02
PO8040	6,213,589	IJ03
PO8071	6,231,163	IJ04
PO8047	6,247,795	IJ05
PO8035	09/113,099	IJ06
PO8044	6,244,691	IJ07
PO8063	6,257,704	IJ08
PO8057	09/112,778	IJ09
PO8056	6,220,694	IJ10
PO8069	6,257,705	IJ11
PO8049	6,247,794	IJ12
PO8036	6,234,610	IJ13
PO8048	6,247,793	IJ14
PO8070	6,264,306	IJ15
PO8067	6,241,342	IJ16
PO8001	6,247,792	IJ17
PO8038	6,264,307	IJ18
PO8033	6,254,220	IJ19
PO8002	6,234,611	IJ20
PO8068	09/112,808	IJ21
PO8062	6,283,582	IJ22
PO8034	6,239,821	IJ23
PO8039	09/113,083	IJ24
PO8041	6,247,796	IJ25
PO8004	09/113,122	IJ26
PO8037	09/112,793	IJ27
PO8043	09/112,794	IJ28
PO8042	09/113,128	IJ29
PO8064	09/113,127	IJ30
PO9389	6,227,653	IJ31
PO9391	6,234,609	IJ32
PP0888	6,238,040	IJ33
PP0891	6,188,415	IJ34
PP0890	6,227,654	IJ35
PP0873	6,209,989	IJ36
PP0993	6,247,791	IJ37
PP0890	09/112,764	IJ38
PP1398	6,217,153	IJ39
PP2592	09/112,767	IJ40
PP2593	6,243,113	IJ41
PP3991	6,283,581	IJ42
PP3987	6,247,790	IJ43
PP3985	6,260,953	IJ44
PP3983	6,267,469	IJ45
PO7935	6,224,780	IJM01
PO7936	6,235,212	IJM02
PO7937	6,280,643	IJM03
PO8061	6,284,147	IJM04
PO8054	6,214,244	IJM05
PO8065	6,071,750	IJM06
PO8055	6,267,905	IJM07
PO8053	6,251,298	IJM08
PO8078	6,258,285	IJM09
PO7933	6,225,138	IJM10
PO7950	6,241,904	IJM11
PO7949	09/113,129	IJM12
PO8060	09/113,124	IJM13
PO8059	6,231,773	IJML4
PO8073	6,190,931	IJM1S
PO8076	6,248,249	IJM16
PO8075	09/113,120	IJM17
PO8079	6,241,906	IJM18
PO8050	09/113,116	IJM19
PO8052	6,241,905	IJM20
PO7948	09/113,117	IJM21
PO7951	6,231,772	IJM22
PO8074	6,274,056	IJM23
PO7941	09/113,110	IJM24
PO8077	6,248,248	IJM25
PO8058	09/113,087	IJM26
PO8051	09/113,074	IJM27
PO8045	6,110,754	IJM28
PO7952	09/113,088	IJM29
PO8046	09/112,771	IJM30
PO9390	6,264,849	IJM31
PO9392	6,254,793	IJM32
PP0889	6,235,211	IJM35
PP0887	09/112,801	IJM36
PP0882	6,264,850	IJM37
PP0874	6,258,284	IJM38
PP1396	09/113,098	IJM39
PP3989	6,228,668	IJM40
PP2591	6,180,427	IJM41
PP3990	6,171,875	IJM42
PP3986	6,267,904	IJM43
PP3984	6,245,247	IJM44
PP3982	09/112,835	IJM45
PP0895	6,231,148	IR01
PP0870	09/113,106	IR02
PP0869	09/113,105	IR04
PP0887	09/113,104	IR05
PP0885	6,238,033	IR06
PP0884	09/112,766	IR10
PP0886	6,238,111	IR12
PP0871	09/113,086	IR13
PP0876	09/113,094	IR14
PP0877	09/112,760	IR16
PP0878	6,196,739	IR17
PP0879	09/112,774	IR18
PP0883	6,270,182	IR19
PP0880	6,152,619	IR20
PP0881	09/113,092	IR21
PO8006	6,087,638	MEMS02
PO8007	09/113,093	MEMS03
PO8008	09/113,062	MEMS04
PO8010	6,041,600	MEMS05
PO8011	09/113,082	MEMS06
PO7947	6,067,797	MEMS07
PO7944	09/113,080	MEMS09
PO7946	6,044,646	MEMS10
PO9393	09/113,065	MEMS11
PP0875	09/113,078	MEMS12
PP0894	09/113,075	MEMS13

FIELD OF THE INVENTION

The present invention relates to a method of enhancement image and, in particular, discloses a process for Utilising Exposure Information in a Digital Image Camera.

The present invention further relates to the field of digital image processing and in particular, the field of processing of images taken with a digital camera.

BACKGROUND OF THE INVENTION

Recently, digital cameras have become increasingly popular. These cameras normally operate by means of imaging a desired image utilising a charge coupled device (CCD) array and storing the imaged scene on an electronic storage medium for later down loading onto a computer system for subsequent manipulation and printing out. Normally, when utilising a computer system to print out an image, sophisticated software may be available to manipulate the image in accordance with requirements.

Unfortunately such systems require significant post processing of a captured image and normally present the image in an orientation in which it was taken, relying on a post processing process to perform any necessary or required modifications of the captured image. Further, much of the environmental information available when the picture was taken is lost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide for the utilisation of exposure information in an image specific manner.

In accordance with a first aspect of the invention there is provided a method of image enhancement of a sensed image taken with a digital camera, said digital camera being hand held and including an area image sensor, internal page width ink jet printer, processor means for processing an output of said area image sensor in accordance with processing rules, and a print roll including print media and printing ink for printing out a processed image on said print media, said digital camera further including an auto exposure setting means, said method comprising the step of utilising exposure setting information from said auto exposure setting means to process said sensed image in accordance with said processing rules.

In accordance with a second aspect of the invention there is provided a method of image enhancement of a sensed image taken with a digital camera, including an auto exposure setting means, said method comprising the step of utilising the auto exposure setting from said auto exposure setting means to process said sensed image to add exposure specific graphics to said image.

The utilising step can comprise utilising the auto exposure setting to determine a re-mapping of colours within the image so as to produce an amended image having colours within an image transformed to take account of the auto exposure setting. The processing can comprise re-mapping image colours so they appear deeper and richer when the exposure setting indicates low light conditions and re-mapping image colours to be brighter and more saturated when the auto exposure setting indicates bright light conditions.

The utilising step includes adding exposure specific graphics to the image.

BRIEF DESCRIPTION OF DRAWINGS

Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0012]
FIG. 1 illustrates the method of operation of the preferred embodiment.[0013]

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

The preferred embodiment is preferably implemented through suitable programming of a hand held camera device such as that described in the concurrently filed application U.S. Ser. No 09/113,060, entitled “A Digital Instant Printing Camera with Image Processing Capability” filed concurrently herewith by the present applicant the content of which is hereby specifically incorporated by cross reference and the details of which, and other related applications are set out in the tables included herein. [0014]
The aforementioned patent specification discloses a camera system, hereinafter known as an “Artcam” type camera, wherein sensed images can be directly printed out by an Artcam portable camera unit. Further, the aforementioned specification discloses means and methods for performing various manipulations on images captured by the camera sensing device leading to the production of various effects in any output image. The manipulations are disclosed to be highly flexible in nature and can be implemented through the insertion into the Artcam of cards having encoded thereon various instructions for the manipulation of images, the cards hereinafter being known as Artcards. The Artcam further has significant onboard processing power provided by an Artcam Central Processor unit (ACP) which is interconnected to a memory device for the storage of important data and image. [0015]
The invention disclosed in U.S. Ser. No. 09/113,060, relates to providing an alternative form of camera system which includes a digital camera with an integral color printer. Additionally, the camera provides hardware and software for the increasing of the apparent resolution of the image sensing system and the conversion of the image to a wide range of “artistic styles” and a graphic enhancement. [0016]
In accordance with the invention, disclosed in U.S. Ser. No. 09/113,060, there is provided a camera system comprising at least one area image sensor for imaging a scene, a camera processor means for processing said imaged scene in accordance with a predetermined scene transformation requirement, a printer for printing out said processed image scene on print media, print media and printing ink stored in a single detachable module inside said camera system, said camera system comprising a portable hand held unit for the imaging of scenes by said area image sensor and printing said scenes directly out of said camera system via said printer. [0017]
Preferably the camera system includes a print roll for the storage of print media and printing ink for utilization by the printer, the print roll being detachable from the camera system. Further, the print roll can include an authentication chip containing authentication information and the camera processing means is adapted to interrogate the authentication chip so as to determine the authenticity of said print roll when inserted within said camera system. [0018]
Further, the printer can include a drop on demand ink printer and guillotine means for the separation of printed photographs. [0019]
In the preferred embodiment, the Artcam has an auto exposure sensor for determining the light level associated with the captured image. This auto exposure sensor is utilised to process the image in accordance with the set light value so as to enhance portions of the image. [0020]
Preferably, the area image sensor includes a means for determining the light conditions when capturing an image. The area image sensor adjusts the dynamic range of values captured by the CCD in accordance with the detected level sensor. The captured image is transferred to the Artcam central processor and stored in the memory store. Intensity information, as determined by the area image sensor, is also forwarded to the ACP. This information is utilised by the Artcam central processor to manipulate the stored image to enhance certain effects. [0021]
Turning now to FIG. 1, the auto exposure setting information [0022] 1 is utilised in conjunction with the stored image 2 to process the image by utilising the ACP. The processed image is returned to the memory store for later printing out 4 on the output printer.
A number of processing steps can be undertaken in accordance with the determined light conditions. Where the auto exposure setting [0023] 1 indicates that the image was taken in a low light condition, the image pixel colours are selectively re-mapped so as to make the image colours stronger, deeper and richer.
Where the auto exposure information indicates that highlight conditions were present when the image was taken, the image colours can be processed to make them brighter and more saturated. The re-colouring of the image can be undertaken by conversion of the image to a hue-saturation-value (HSV) format and an alteration of pixel values in accordance with requirements. The pixel values can then be output converted to the required output colour format of printing. [0024]
Of course, many different re-colouring techniques may be utilised. Preferably, the techniques are clearly illustrated on the pre-requisite artcard inserted into the reader. Alternatively, the image processing algorithms can be automatically applied and hard-wired into the camera for utilization in certain conditions. [0025]
Alternatively, the Artcard inserted could have a number of manipulations applied to the image which are specific to the auto-exposure setting. For example, clip arts containing candles etc could be inserted in a dark image and large suns inserted in bright images. [0026]
It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiment without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive. [0027]
The present invention is best utilized in the Artcam device, the details of which are set out in the following paragraphs. [0028]
Ink Jet Technologies [0029]
The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable. [0030]
The most significant problem with thermal ink jet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out. [0031]
The most significant problem with piezoelectric ink jet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of pagewidth print heads with 19,200 nozzles. [0032]
Ideally, the ink jet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new ink jet technologies have been created. The target features include: [0033]
low power (less than 10 Watts) [0034]
high resolution capability (1,600 dpi or more) [0035]
photographic quality output [0036]
low manufacturing cost [0037]
small size (pagewidth times minimum cross section) [0038]
high speed (<2 seconds per page). [0039]
All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table under the heading Cross References to Related Applications. [0040]
The ink jet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems [0041]
For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the ink jet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry. [0042]
Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding. [0043]
Tables of Drop-on-Demand Ink Jets [0044]
Eleven important characteristics of the fundamental operation of individual ink jet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee. [0045]
The following tables form the axes of an eleven dimensional table of ink jet types. [0046]
Actuator mechanism (18 types) [0047]
Basic operation mode (7 types) [0048]
Auxiliary mechanism (8 types) [0049]
Actuator amplification or modification method (17 types) [0050]
Actuator motion (19 types) [0051]
Nozzle refill method (4 types) [0052]
Method of restricting back-flow through inlet (10 types) [0053]
Nozzle clearing method (9 types) [0054]
Nozzle plate construction (9 types) [0055]
Drop ejection direction (5 types) [0056]
Ink type (7 types) [0057]
The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of ink jet nozzle. While not all of the possible combinations result in a viable ink jet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain ink jet types have been investigated in detail. These are designated IJ01 to IJ45 which match the docket numbers in the table under the heading Cross References to Related Applications. [0058]
Other ink jet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into ink jet print heads with characteristics superior to any currently available ink jet technology. [0059]
Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a print technology may be listed more than once in a table, where it shares characteristics with more than one entry. [0060]
Suitable applications for the ink jet technologies include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc. [0061]

The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.



		Dis-
Description	Advantages	advantages	Examples

ACTUATOR MECHANISM

(APPLIED ONLY TO SELECTED INK DROPS)

Thermal	An electrothermal	Large force	High power	Canon
bubble	heater heats the	generated	Ink carrier	Bubblejet
	ink to above	Simple	limited to	1979 Endo
	boiling point,	construction	water	et al GB
	transferring	No moving	Low	patent
	significant heat to	parts	efficiency	2,007,162
	the aqueous ink.	Fast	High	Xerox
	A bubble	operation	temperatures	heater-in-pit
	nucleates and	Small chip	required	1990
	quickly forms,	area required	High	Hawkins et
	expelling the ink.	for actuator	mechamcal	al USP
	The efficiency of		stress	4,899,181
	the process is		Unusual	Hewlett-
	low, with		materials	Packard TIJ
	typically less		required	1982 Vaught
	than 0.05% of the		Large drive	et al USP
	electrical energy		transistors	4,490,728
	being transformed		Cavitation
	into kinetic		causes
	energy of the		actuator
	drop.		failure
			Kogation
			reduces
			bubble
			formation
			Large print
			heads are
			difficult to
			fabricate
Piezo-	A piezoelectric	Low power	Very large	Kyser et al
electric	crystal such as	consumption	area required	USP
	lead lanthanum	Many ink	for actuator	3,946,398
	zirconate (PZT) is	types can be	Difficult to	Zoltan USP
	electrically	used	integrate	3,683,212
	activated, and	Fast	with	1973
	either expands,	operation	electronics	Stemme USP
	shears, or bends	High	High	3,747,120
	to apply pressure	efficiency	voltage drive	Epson
	to the ink,	required	transistors	Stylus
	ejecting drops.		Full page-	Tektronix
			width print	IJ04
			heads
			impractical
			due to
			actuator size
			Requires
			electrical
			poling in
			high field
			strengths
			during
			manufacture
Electro-	An electric field	Low power	Low	Seiko Epson,
strictive	is used to activate	consumption	maximum	Usui et all JP
	electrostriction in	Many ink	strain	253401/96
	relaxor materials	types can	(approx.	IJ04
	such as lead	be used	0.01%)
	lanthanum	Low	Large area
	zirconate titanate	thermal	required for
	(PLZT) or lead	expansion	actuator due
	magnesium	Electric	to low strain
	niobate (PMN).	field strength	Response
		required	speed is
		(approx. 3.5	marginal
		V/μm) can	(˜10 μs)
		be generated	High voltage
		without	drive
		difficulty	transistors
		Does not	required
		require	Full
		electrical	pagewidth
		poling	print heads
			impractical
			due to
			actuator size
Ferro-	An electric field	Low power	Difficult to	IJ04
electric	is used to induce	consumption	integrate
	a phase transition	Many ink	with
	between the	types can	electronics
	antiferroelectric	be used	Unusual
	(AFE) and	Fast	materials
	ferroelectric (FE)	operation	such as
	phase. Perovskite	(<1 μs)	PLZSnT are
	materials such as	Relatively	required
	tin modified lead	high	Actuators
	lanthanum	longitudinal	require a
	zirconate titanate	strain	large
	(PLZSnT) exhibit	High	area
	large strains of up	efficiency
	to 1% associated	Electric
	with the AFE to	field strength
	FE phase	of around
	transition.	3 V/μm can
		be readily
		provided
Electro-	Conductive plates	Low power	Difficult to	IJ02, IJ04
static	are separated by a	consumption	operate
plates	compressible or	Many ink	electrostatic
	fluid dielectric	types can	devices in
	(usually air).	be used	an aqueous
	Upon application	Fast	environment
	of a voltage, the	operation	The
	plates attract each		electrostatic
	other and displace		actuator will
	ink, causing drop		normally
	ejection. The		need to be
	conductive plates		separated
	maybe in a comb		from the ink
	or honeycomb		Very large
	structure, or		area required
	stacked to		to achieve
	increase the		high forces
	surface area		High
	and therefore the		voltage drive
	force.		transistors
			may be
			required
			Full page-
			width print
			heads are not
			competitive
			due to
			actuator size
Electro-	A strong electric	Low current	High voltage	1989 Saito
static	field is applied to	consumption	required	et al, USP
pull on	the ink, where-	Low	May be	4,799,068
ink	upon electrostatic	temperature	damaged by	1989 Miura
	attraction		sparks due	et al, USP
	accelerates the		to air	4,810,954
	ink towards the		breakdown	Tone-jet
	print medium.		Required
			field strength
			increases as
			the drop size
			decreases
			High
			voltage drive
			transistors
			required
			Electrostatic
			field attracts
			dust
Permanent	An electromagnet	Low power	Complex	IJ07, IJ10
magnet	directly attracts	consumption	fabrication
electro-	a permanent	Many ink	Permanent
magnetic	magnet,	types can	magnetic
	displacing ink and	be used	material
	causing drop	Fast	such as
	ejection. Rare	operation	Neodymium
	earth magnets	High	Iron Boron
	with a field	efficiency	(NdFeB)
	strength around 1	Easy	required.
	Tesla can be	extension	High local
	used. Examples	from single	currents
	are: Samarium	nozzles to	required
	Cobalt (SaCo)	pagewidth	Copper
	and magnetic	print heads	metalization
	materials in the		should be
	neodymium iron		used for long
	boron family		electro-
	(NdFeB,		migration
	NdDyFeBNb,		lifetime
	NdDyFeB, etc)		and low
			resistivity
			Pigmented
			inks are
			usually
			infeasible
			Operating
			temperature
			limited to
			the Curie
			temperature
			(around
			540 K)
Soft	A solenoid	Low power	Complex	IJ01, IJ05,
magnetic	induced a	consumption	fabrication	IJ08, IJ10,
core	magnetic field in	Many ink	Materials	IJ12, IJ14,
electro-	a soft magnetic	types can	not usually	IJ15, IJ17
magnetic	core or yoke	be used	present in
	fabricated from a	Fast	a CMOS fab
	ferrous material	operation	such as
	such as electro-	High	NiFe,
	plated iron alloys	efficiency	CoNiFe, or
	such as CoNiFe	Easy	CoFe are
	[1], CoFe, or	extension	required
	NiFe alloys.	from single	High local
	Typically, the soft	nozzles to	currents
	magnetic material	pagewidth	required
	is in two parts,	print heads	Copper
	which are		metalization
	normally held		should be
	apart by a spring.		used for long
	When the		electro-
	solenoid is		migration
	actuated, the two		lifetime
	parts attract,		and low
	displacing the		resistivity
	ink.		Electro-
			plating is
			required
			High
			saturation
			flux density
			is required
			(2.0-2.1 T is
			achievable
			with CoNiFe
			[1])
Lorenz	The Lorenz force	Low power	Force acts	IJ06, IJ11,
force	acting on a	consumption	as a twisting	IJ13, IJ16
	current carrying	Many ink	motion
	wire in a	types can	Typically,
	magnetic field is	be used	only a
	utilized.	Fast	quarter of
	This allows the	operation	the solenoid
	magnetic field to	High	length
	be supplied	efficiency	provides
	externally to the	Easy	force in a
	pnnt head, for	extension	useful
	example with rare	from single	direction
	earth permanent	nozzles to	High local
	magnets.	pagewidth	currents
	Only the current	print heads	required
	carrying wire		Copper
	need be fabricated		metalization
	on the print-head,		should be
	simplifying		used for
	materials		long electro-
	requirements.		migration
			lifetime
			and low
			resistivity
			Pigmented
			inks are
			usually
			infeasible
Magneto-	The actuator uses	Many ink	Force acts	Fisehenbeck,
striction	the giant	types can	as a twisting	USP
	magnetostrictive	be used	motion	4,032,929
	effect of materials	Fast	Unusual	IJ25
	such as	operation	materials
	Terfenol-D (an	Easy	such as
	alloy of terbium,	extension	Terfenol-D
	dysprosium and	from single	are required
	iron developed at	nozzles to	High local
	the Naval	pagewidth	currents
	Ordnance	print heads	required
	Laboratory, hence	High force	Copper
	Ter-Fe-NOL). For	is available	metalization
	best efficiency,		should be
	the actuator		used for long
	should be pre-		electro-
	stressed to		migration
	approx. 8 MPa.		lifetime
			and low
			resistivity
			Pre-stressing
			may be
			required
Surface	Ink under positive	Low power	Requires	Silverbrook,
tension	pressure is held in	consumption	supple-	EP 0771
reduction	a nozzle by	Simple	mentary	658 A2
	surface tension.	construction	force to	and related
	The surface	No unusual	effect	patent
	tension of	materials	drop	applications
	the ink is reduced	required in	separation
	below the bubble	fabrication	Requires
	threshold, causing	High	special ink
	the ink to egress	efficiency	surfactants
	from the nozzle.	Easy	Speed may
		extension	be limited by
		from single	surfactant
		nozzles to	properties
		pagewidth
		print heads
Viscosity	The ink viscosity	Simple	Requires	Silverbrook,
reduction	is locally reduced	construction	supple-	EP 0771
	to select which	No unusual	mentary	658 A2
	drops are to be	materials	force to	and related
	ejected. A vis-	required in	effect drop	patent
	cosity reduction	fabrication	separation	applications
	can be achieved	Easy	Requires
	electrothermally	extension	special ink
	with most inks,	from single	viscosity
	but special inks	nozzles to	properties
	can be engineered	pagewidth	High speed
	for a 100:1	print heads	is difficult
	viscosity		to achieve
	reduction.		Requires
			oscillating
			ink pressure
			A high
			temperature
			difference
			(typically 80
			degrees) is
			required
Acoustic	An acoustic wave	Can operate	Complex	1993
	is generated and	without a	drive	Hadimioglu
	focussed upon the	nozzle plate	circuitry	et al, EUP
	drop ejection		Complex	550,192
	region.		fabrication	1993 Elrod
			Low	et al, EUP
			efficiency	572,220
			Poor control
			of drop
			position
			Poor control
			of drop
			volume
Thermo-	An actuator	Low power	Efficient	IJ03, IJ09,
elastic	which relies upon	consumption	aqueous	IJ17, IJ18,
bend	differential	Many ink	operation	IJ19, IJ20,
actuator	thermal expansion	types can	requires a	IJ21, IJ22,
	upon Joule	be used	thermal	IJ23, IJ24,
	heating is used.	Simple	insulator on	IJ27, IJ28,
		planar	the hot side	IJ29, IJ30,
		fabrication	Corrosion	IJ31, IJ32,
		Small chip	prevention	IJ33, IJ34,
		area required	can be	IJ35, IJ36,
		for each	difficult	IJ37, IJ38,
		actuator	Pigmented	IJ39, IJ40,
		Fast	inks may be	IJ41
		operation	infeasible,
		High	as pigment
		efficiency	particles may
		CMOS	jam the bend
		compatible	actuator
		voltages and
		currents
		Standard
		MEMS
		processes
		can be used
		Easy
		extension
		from single
		nozzles to
		pagewidth
		print heads
High CTE	A material with a	High force	Requires	IJ09, IJ17,
thermo-	very high	can be	special	IJ18, IJ20,
elastic	coefficient of	generated	material	IJ21, IJ22,
actuator	thermal expansion	Three	(e.g. PTFE)	IJ23, IJ24,
	(CTE) such as	methods of	Requires a	IJ27, IJ28,
	polytetrafluoro-	PTFE	PTFE	IJ29, IJ30,
	ethylene (PTFE)	deposition	deposition	IJ31, IJ42,
	is used. As high	are under	process,	IJ43, IJ44
	GTE materials are	develop-	which is not
	usually non-	ment:	yet standard
	conductive, a	chemical	in ULSI fabs
	heater fabricated	vapor	PTFE
	from a conductive	deposition	deposition
	material is	(CVD), spin	cannot be
	incorporated. A	coating, and	followed
	50 μm long PTFE	evaporation	with high
	bend actuator	PTFE is a	temperature
	with polysilicon	candidate	(above
	heater and 15	for low	350° C.)
	mW power input	dielectric	processing
	can provide 180	constant	Pigmented
	μN force and 10	insulation	inks may be
	μm deflection.	in ULSI	infeasible,
	Actuator motions	Very low	as pigment
	include:	power	particles may
	Bend	consumption	jam the bend
	Push	Many ink	actuator
	Buckle	types can
	Rotate	be used
		Simple
		planar
		fabrication
		Small chip
		area required
		for each
		actuator
		Fast
		operation
		High
		efficiency
		CMOS
		compatible
		voltages and
		currents
		Easy
		extension
		from single
		nozzles to
		pagewidth
		print heads
Con-	A polymer with a	High force	Requires	IJ24
ductive	high coefficient	can be	special
polymer	of thermal	generated	materials
thermo-	expansion (such	Very low	development
elastic	as PTFE) is	power	(High CTE
actuator	doped with	consumption	conductive
	conducting	Many ink	polymer)
	substances to	types can	Requires a
	increase its	be used	PTFE
	conductivity to	Simple	deposition
	about 3 orders of	planar	process,
	magnitude below	fabrication	which
	that of copper.	Small chip	is not yet
	The conducting	area required	standard in
	polymer expands	for each	ULSI fabs
	when resistively	actuator	PTFE
	heated.	Fast	deposition
	Examples of	operation	cannot be
	conducting	High	followed
	dopants include:	efficiency	with high
	Carbon nanotubes	CMOS	temperature
	Metal fibers	compatible	(above
	Conductive	voltages and	350° C.)
	polymers such as	currents	processing
	doped	Easy	Evaporation
	polythiophene	extension	and CVD
	Carbon granules	from single	deposition
		nozzles to	techniques
		pagewidth	cannot
		print heads	be used
			Pigmented
			inks may be
			infeasible,
			as pigment
			particles
			may jam
			the bend
			actuator
Shape	A shape memory	High force	Fatigue	IJ26
memory	alloy such as TiNi	is available	limits
alloy	(also known as	(stresses of	maximum
	Nitinol-Nickel	hundreds of	number of
	Titanium alloy	MPa)	cycles
	developed at the	Large strain	Low strain
	Naval Ordnance	is available	(1%) is
	Laboratory) is	(more than	required to
	thermally	3%)	extend
	switched between	High	fatigue
	its weak	corrosion	resistance
	martensitic state	resistance	Cycle rate
	and its high	Simple	limited by
	stiffness austenic	construction	heat removal
	state. The shape	Easy	Requires
	of the actuator in	extension	unusual
	its martensitic	from single	materials
	state is deformed	nozzles to	(TiNi)
	relative to the	pagewidth	The latent
	austenic shape.	print heads	heat of
	The shape change	Low voltage	trans-
	causes ejection of	operation	formation
	a drop.		must be
			provided
			High current
			operation
			Requires
			pre-stressing
			to distort
			the
			martensitic
			state
Linear	Linear magnetic	Linear	Requires	IJ12
Magnetic	actuators include	Magnetic	unusual
Actuator	the Linear In-	actuators	semi-
	duction Actuator	can be	conductor
	(LIA), Linear	constructed	materials
	Permanent	with high	such
	Magnet	thrust, long	as soft
	Synchronous	travel, and	magnetic
	Actuator	high	alloys
	(LPMSA), Linear	efficiency	(e.g.
	Reluctance	using planar	CoNiFe)
	Synchronous	semi-	Some
	Actuator (LRSA),	conductor	varieties
	Linear Switched	fabrication	also require
	Reluctance	techniques	permanent
	Actuator (LSRA),	Long	magnetic
	and the Linear	actuator	materials
	Stepper Actuator	travel is	such as
	(LSA).	available	Neodymium
		Medium	iron boron
		force is	(NdFeB)
		available	Requires
		Low voltage	complex
		operation	multi-phase
			drive
			circuitry
			High current
			operation

BASIC OPERATION MODE

Actuator	This is the	Simple	Drop	Thermal
directly	simplest mode of	operation	repetition	ink jet
pushes	operation: the	No external	rate is	Piezoelectric
ink	actuator directly	fields	usually	ink jet
	supplies sufficient	required	limited to	IJ01, IJ02,
	kinetic energy to	Satellite	around	IJ03, IJ04,
	expel the drop.	drops can	10 kHz.	IJ05, IJ06,
	The drop must	be avoided	However,	IJ07, IJ09,
	have a sufficient	if drop	this is not	IJ11, IJ12,
	velocity to	velocity is	the method,	IJ14, IJ16,
	overcome the	less than	but	IJ20, IJ22,
	surface tension.	4 m/s	fundamental	IJ23, IJ24,
		Can be	to is related	IJ25, IJ26,
		efficient,	to the refill	IJ27, IJ28,
		depending	method	IJ29, IJ30,
		upon the	normally	IJ31, IJ32,
		actuator	used	IJ33, IJ34,
		used	All of the	IJ35, IJ36,
			drop kinetic	IJ37, IJ38,
			energy must	IJ39, IJ40,
			be provided	IJ41, IJ42,
			by the	IJ43, IJ44
			actuator
			Satellite
			drops usually
			form if drop
			velocity
			is greater
			than 4.5 m/s
Proximity	The drops to be	Very simple	Requires	Silverbrook,
	printed are	print head	close	EP 0771
	selected by some	fabrication	proximity	658 A2
	manner (e.g.	can be used	between the	and related
	thermally induced	The drop	print head	patent
	surface tension	selection	and the	applications
	reduction of	means does	print media
	pressurized ink).	not need to	or transfer
	Selected drops are	provide the	roller
	separated from	energy	May require
	the ink in the	required to	two print
	nozzle by contact	separate the	heads
	with the print	drop from	printing
	medium or a	the nozzle	alternate
	transfer roller.		rows of
			the image
			Monolithic
			color print
			heads are
			difficult
Electra-	The drops to be	Very simple	Requires	Silverbrook,
static	printed are	print head	very high	EP 0771
pull on	selected by some	fabrication	electrostatic	658 A2
ink	manner (e.g.	can be used	field	and related
	thermally induced	The drop	Electrostatic	patent
	surface tension	selection	field for	applications
	reduction of	means does	small	Tone-Jet
	pressurized ink).	not need to	nozzle sizes
	Selected drops are	provide the	is above air
	separated from	energy	breakdown
	the ink in the	required to	Electrostatic
	nozzle by a strong	separate the	field may
	electric field.	drop from	attract dust
		the nozzle
Magnetic	The drops to be	Very simple	Requires	Silverbrook,
pull on	printed are	print head	magnetic ink	EP 0771
ink	selected by some	fabrication	Ink colors	658 A2
	manner (e.g.	can be used	other than	and related
	thermally induced	The drop	black are	patent
	surface tension	selection	difficult	applications
	reduction of	means does	Requires
	pressurized ink),	not need to	very high
	Selected drops are	provide the	magnetic
	separated from	energy	fields
	the ink in the	required to
	nozzle by a strong	separate the
	magnetic field	drop from
	acting on the	the nozzle
	magnetic ink.
Shutter	The actuator	High speed	Moving parts	IJ13, IJ17,
	moves a shutter to	(>50 kHz)	are required	IJ21
	block ink flow to	operation	Requires ink
	the nozzle. The	can be	pressure
	ink pressure is	achieved due	modulator
	pulsed at a	to reduced	Friction and
	multiple of the	refill time	wear must be
	drop ejection	Drop timing	considered
	frequency.	can be very	Stiction is
		accurate	possible
		The actuator
		energy can
		be very low
Shuttered	The actuator	Actuators	Moving parts	IJ08, IJ15,
grill	moves a shutter to	with small	are required	IJ18, IJ19
	block ink flow	travel can	Requires ink
	through a grill to	be used	pressure
	the nozzle. The	Actuators	modulator
	shutter movement	with small	Friction and
	need only be	force can	wear must be
	equal to the width	be used	considered
	of the grill holes.	High speed	Stiction is
		(>50 kHz)	possible
		operation
		can be
		achieved
Pulsed	A pulsed	Extremely	Requires an	IJ10
magnetic	magnetic field	low energy	external
pull on	attracts an ‘ink	operation is	pulsed
ink	pusher’ at the	possible	magnetic
pusher	drop ejection	No heat	field
	frequency. An	dissipation	Requires
	actuator controls	problems	special
	a catch, which		materials
	prevents the ink		for both the
	pusher from		actuator
	moving when a		and the
	drop is not		ink pusher
	to be ejected.		Complex
			construction

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)

None	The actuator	Simplicity of	Drop	Most ink
	directly fires the	construction	ejection	jets,
	ink drop, and	Simplicity of	energy	including
	there is no	operation	must be	piezoelectric
	external field or	Small	supplied by	and thermal
	other mechanism	physical size	individual	bubble.
	required.		nozzle	IJ01, IJ02,
			actuator	IJ03, IJ04,
				IJ05, IJ07,
				IJ09, IJ11,
				IJ12, IJ14,
				IJ20, IJ22,
				IJ23, IJ24,
				IJ25, IJ26,
				IJ27, IJ28,
				IJ29, IJ30,
				IJ31, IJ32,
				IJ33, IJ34,
				IJ35, IJ36,
				IJ37, IJ38,
				IJ39, IJ40,
				IJ41, IJ42,
				IJ43, IJ44
Oscillating	The ink pressure	Oscillating	Requires	Silverbrook,
ink	oscillates,	ink pressure	external ink	EP 0771
pressure	providing much	can provide	pressure	658 A2
(including	of the drop	a refill	oscillator	and related
acoustic	ejection energy.	pulse,	Ink pressure	patent
stimu-	The actuator	allowing	phase and	applications
lation)	selects which	higher	amplitude	IJ08, IJ13,
	drops are to be	operating	must be	IJ15, IJ17,
	fired by	speed	carefully	IJ18, IJ19,
	selectively	The	controlled	IJ21
	blocking or	actuators	Acoustic
	enabling nozzles.	may operate	reflections
	The ink pressure	with much	in the ink
	oscillation may be	lower energy	chamber
	achieved by	Acoustic	must be
	vibrating the print	lenses can be	designed for
	head, or	used to focus
	preferably by	the sound on
	an actuator in	the nozzles
	the ink supply.
Media	The print head is	Low power	Precision	Silverbrook,
proximity	placed in close	High	assembly	EP 0771
	proximity to the	accuracy	required	658 A2
	print medium.	Simple print	Paper fibers	and related
	Selected drops	head	may cause	patent
	protrude from the	construction	problems	applications
	print head further		Cannot print
	than unselected		on rough
	drops, and contact		substrates
	the print medium.
	The drop soaks
	into the medium
	fast enough to
	cause drop
	separation.
Transfer	Drops are printed	High	Bulky	Silverbrook,
roller	to a transfer roller	accuracy	Expensive	EP 0771
	instead of straight	Wide range	Complex	658 A2
	to the print	of print	construction	and related
	medium. A	substrates		patent
	transfer roller can	can be used		applications
	also be used for	Ink can be		Tektronix
	proximity drop	dried on the		hot melt
	separation.	transfer		piezoelectric
		roller		ink jet
				Any of the
				IJ series
Electro-	An electric field	Low power	Field	Silverbrook,
static	is used to	Simple	strength	EP 0771
	accelerate	print head	required for	658 A2
	selected drops	construction	separation	and related
	towards the print		of small	patent
	medium.		drops is	applications
			near or	Tone-Jet
			above air
			breakdown
Direct	A magnetic field	Low power	Requires	Silverbrook,
magnetic	is used to	Simple	magnetic ink	EP 0771
field	accelerate	print head	Requires	658 A2
	selected drops of	construction	strong	and related
	magnetic ink		magnetic	patent
	towards the print		field	applications
	medium.
Cross	The print head is	Does not	Requires	IJ06, IJ16
magnetic	placed in a	require	external
field	constant magnetic	magnetic	magnet
	field. The Lorenz	materials	Current
	force in a current	to be	densities
	canying wire is	integrated	may be high,
	used to move the	in the	resulting in
	actuator.	print head	electro-
		manu-	migration
		facturing	problems
		process
Pulsed	A pulsed	Very low	Complex	IJ10
magnetic	magnetic field is	power	print head
field	used to cyclically	operation	construction
	attract a paddle,	is possible	Magnetic
	which pushes on	Small print	materials
	the ink. A small	head size	required in
	actuator moves a		print head
	catch, which
	selectively
	prevents the
	paddle from
	moving.

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD

None	No actuator	Operational	Many	Thermal
	mechanical	simplicity	actuator	Bubble
	amplification		mechanisms	Ink jet
	is used. The		have	IJ01, IJ02,
	actuator directly		insufficient	IJ06, IJ07,
	drives the drop		travel, or	IJ16, IJ25,
	ejection process.		insufficient	IJ26
			force, to
			efficiently
			drive the
			drop
			ejection
			process
Differ-	An actuator	Provides	High stresses	Piezoelectric
ential	material expands	greater	are involved	IJ03, IJ09,
expansion	more on one side	travel in a	Care must be	IJ17, IJ18,
bend	than on the other.	reduced print	taken that	IJ19, IJ20,
actuator	The expansion	head area	the materials	IJ21, IJ22,
	may be thermal,		do not	IJ23, IJ24,
	piezoelectric,		delaminate	IJ27, IJ29,
	magnetostrictive,		Residual	IJ30, IJ31,
	or other		bend	IJ32, IJ33,
	mechanism. The		resulting	IJ34, IJ35,
	bend actuator		from high	IJ36, IJ37,
	converts a high		temperature	IJ38, IJ39,
	force low travel		or high	IJ42, IJ43,
	actuator		stress	IJ44
	mechanism to		during
	high travel,		formation
	lower force
	mechanism.
Transient	A trilayer bend	Very good	High stresses	IJ40, IJ41
bend	actuator where	temperature	are involved
actuator	the two outside	stability	Care must be
	layers are	High speed,	taken that
	identical. This	as a new	the materials
	cancels bend due	drop can be	do not
	to ambient	fired before	delaminate
	temperature and	heat
	residual stress.	dissipates
	The actuator only	Cancels
	responds to	residual
	transient heating	stress of
	of one side	formation
	or the other.
Reverse	The actuator	Better	Fabrication	IJ05, IJ11
spring	loads a spring.	coupling to	complexity
	When the actuator	the ink	High stress
	is turned off, the		in the spring
	spring releases.
	This can reverse
	the force/distance
	curve of the
	actuator to make
	it compatible with
	the force/time
	requirements of
	the drop ejection.
Actuator	A series of thin	Increased	Increased	Some
stack	actuators are	travel	fabrication	piezoelectric
	stacked. This can	Reduced	complexity	ink jets
	be appropriate	drive	Increased	IJ04
	where actuators	voltage	possibility
	require high		of short
	electric field		circuits
	strength, such as		due to
	electrostatic and		pinholes
	piezoelectric
	actuators.
Multiple	Multiple smaller	Increases	Actuator	IJ12, IJ13,
actuators	actuators are used	the force	forces	IJ18, IJ20,
	simultaneously to	available	may not add	IJ22, IJ28,
	move the ink.	from an	linearly,	IJ42, IJ43
	Each actuator	actuator	reducing
	need provide only	Multiple	efficiency
	a portion of the	actuators
	force required.	can be
		positioned
		to control
		ink flow
		accurately
Linear	A linear spring is	Matches	Requires	IJ15
Spring	used to transform	low travel	print head
	a motion with	actuator	area for
	small travel and	with higher	the spring
	high force into a	travel
	longer travel,	requirements
	lower force	Non-contact
	motion.	method of
		motion trans-
		formation
Coiled	A bend actuator is	Increases	Generally	IJ17, IJ21,
actuator	coiled to provide	travel	restricted	IJ34, IJ35
	greater travel in a	Reduces	to planar
	reduced chip area.	chip area	imple-
		Planar	mentations
		imple-	due to
		mentations	extreme
		are relatively	fabrication
		easy to	difficulty
		fabricate.	in other
			orientations.
Flexure	A bend actuator	Simple	Care must be	IJ10, IJ19,
bend	has a small region	means of	taken not to	IJ33
actuator	near the fixture	increasing	exceed the
	point, which	travel of	elastic limit
	flexes much more	a bend	in the flexure
	readily than the	actuator	area
	remainder of the		Stress
	actuator. The		distribution
	actuator flexing		is very
	is effectively		uneven
	converted from an		Difficult to
	even coiling to an		accurately
	angular bend,		model with
	resulting in		finite
	greater travel of		element
	the actuator tip.		analysis
Catch	The actuator	Very low	Complex	IJ10
	controls a small	actuator	construction
	catch. The catch	energy	Requires
	either enables	Very small	external
	or disables	actuator size	force
	movement	Unsuitable
	of an ink pusher		for
	that is controlled		pigmented
	in a bulk manner.		inks
Gears	Gears can be used	Low force,	Moving parts	IJ13
	to increase travel	low travel	are required
	at the expense of	actuators	Several
	duration. Circular	can be used	actuator
	gears, rack and	Can be	cycles
	pinion, ratchets,	fabricated	are required
	and other gearing	using	More
	methods can be	standard	complex
	used.	surface	drive
		MEMS	electronics
		processes	Complex
			construction
			Friction,
			friction, and
			wear are
			possible
Buckle	A buckle plate	Very fast	Must stay	S. Hirata
plate	can be used to	movement	within	et al, “An
	change a slow	achievable	elastic limits	Ink-jet Head
	actuator into a		of the	Using
	fast motion. It can		materials for	Diaphragm
	also convert a		long device	Micro-
	high force, low		life	actuator”,
	travel actuator		High stresses	Proc. IEEE
	into a high		involved	MEMS, Feb.
	travel, medium		Generally	1996,
	force motion.		high power	pp 418-423.
			requirement	IJ18, IJ27
Tapered	A tapered	Linearizes	Complex	IJ14
magnetic	magnetic pole	the magnetic	construction
pole	can increase	force/
	travel at the	distance
	expense of force.	curve
Lever	A lever and	Matches	High	IJ32, IJ36,
	fulcrum is used	low travel	stress	IJ37
	to transform a	actuator with	around the
	motion with small	higher travel	fulcrum
	travel and high	requirements
	force into a	Fulcrum
	motion with	area has no
	longer travel and	linear
	lower force. The	movement,
	lever can also	and can be
	reverse the	used for a
	direction of	fluid seal
	travel.
Rotary	The actuator is	High	Complex	IJ28
impeller	connected to a	mechanical	construction
	rotary impeller. A	advantage	Unsuitable
	small angular	The ratio of	for
	deflection of the	force to	pigmented
	actuator results in	travel of the	inks
	a rotation of the	actuator
	impeller vanes,	can be
	which push the	matched to
	ink against	the nozzle
	stationary vanes	requirements
	and out of the	by varying
	nozzle.	the number
		of impeller
		vanes
Acoustic	A refractive or	No moving	Large area	1993
lens	diffractive (e.g.	parts	required	Hadimioglu
	zone plate)		Only	et al, EUP
	acoustic lens		relevant	550,192
	is used to		for acoustic	1993 Elrod
	concentrate sound		ink jets	et al, EUP
	waves.			572,220
Sharp	A sharp point is	Simple	Difficult to	Tone-jet
conductive	used to con-	construction	fabricate
point	centrate an		using
	electrostatic		standard
	field.		VLSI
			processes
			for a
			surface
			ejecting
			ink-jet
			Only
			relevant for
			electrostatic
			ink jets

ACTUATOR MOTION

Volume	The volume of	Simple	High energy	Hewlett-
expansion	the actuator	construction	is typically	Packard
	changes, pushing	in the case	required to	Thermal
	the ink in all	of thermal	achieve	Ink jet
	directions.	ink jet	volume	Canon
			expansion.	Bubblejet
			This leads
			to thermal
			stress,
			cavitation,
			and kogation
			in thermal
			ink jet
			imple-
			mentations
Linear,	The actuator	Efficient	High	IJ01, IJ02,
normal	moves in a	coupling to	fabrication	IJ04, IJ07,
to chip	direction normal	ink drops	complexity	IJ11, IJ14
surface	to the print head	ejected	may be
	surface. The	normal to	required to
	nozzle is typically		achieve the
	in the line of		surface per-
	movement.		pendicular
			motion
Parallel	The actuator	Suitable for	Fabrication	IJ12, IJ13,
to chip	moves parallel to	planar	complexity	IJ15, IJ33,
surface	the print head	fabrication	Friction	IJ34, IJ35,
	surface. Drop		Stiction	IJ36
	ejection may still
	be normal to the
	surface.
Membrane	An actuator with	The effective	Fabrication	1982
push	a high force but	area of the	complexity	Howkins
	small area is used	actuator	Actuator size	USP
	to push a stiff	becomes the	Difficulty of	4,459,601
	membrane that is	membrane	integration
	in contact with	area	in a VLSI
	the ink.		process
Rotary	The actuator	Rotary	Device	IJ05, IJ08,
	causes the	levers may	complexity	IJ13, IJ28
	rotation of some	be used to	May have
	element, such a	increase	friction
	grill or impeller	travel	at a pivot
		Small chip	point
		area
		requirements
Bend	The actuator	A very	Requires the	1970 Kyser
	bends when	small	actuator to	et al USP
	energized. This	change in	be made	3,946,398
	may be due to	dimensions	from at	1973
	differential	can be	least two	Stemme
	thermal	converted	distinct	USP
	expansion,	to a large	layers, or	3,747,120
	piezoelectric	motion.	to have a	IJ03, IJ09,
	expansion,		thermal	IJ10, IJ19,
	magnetostriction,		difference	IJ23, IJ24,
	or other form of		across the	IJ25, IJ29,
	relative		actuator	IJ30, IJ31,
	dimensional			IJ33, IJ34,
	change.			IJ35
Swivel	The actuator	Allows	Inefficient	IJ06
	swivels around a	operation	coupling to
	central pivot. This	where the	the ink
	motion is suitable	net linear	motion
	where there are	force on
	opposite forces	the paddle
	applied to	is zero
	opposite sides of	Small chip
	the paddle, e.g.	area
	Lorenz force.	requirements
Straighten	The actuator is	Can be used	Requires	IJ26, IJ32
	normally bent,	with shape	careful
	and straightens	memory	balance of
	when energized.	alloys where	stresses to
		the austenic	ensure that
		phase is	the quiescent
		planar	bend is
			accurate
Double	The actuator	One	Difficult	IJ36, IJ37,
bend	bends in one	actuator can	to make	IJ38
	direction when	be used to	the drops
	one element is	power two	ejected by
	energized, and	nozzles.	both bend
	bends the other	Reduced	directions
	way when another	chip size.	identical.
	element is	Not	A small
	energized.	sensitive	efficiency
		to ambient	loss
		temperature	compared to
			equivalent
			single bend
			actuators.
Shear	Energizing the	Can increase	Not readily	1985
	actuator causes a	the effective	applicable	Fishbeck
	shear motion in	travel of	to other	USP
	the actuator	piezoelectric	actuator	4,584,590
	material.	actuators	mechanisms
Radial	The actuator	Relatively	High force	1970
con-	squeezes an ink	easy to	required	Zoltan
striction	reservoir, forcing	fabricate	Inefficient	USP
	ink from a	single	Difficult to	3,683,212
	constricted	nozzles	integrate
	nozzle.	from glass	with VLSI
		tubing as	processes
		macroscopic
		structures
Coil/	A coiled actuator	Easy to	Difficult to	IJ17, IJ21,
uncoil	uncoils or coils	fabricate	fabricate for	IJ34, IJ35
	more tightly. The	as a planar	non-planar
	motion of the free	VLSI	devices
	end of the	process	Poor out-of-
	actuator ejects	Small area	plane
	the ink.	required,	stiffness
		therefore
		low cost
Bow	The actuator	Can increase	Maximum	IJ16, IJ18,
	bows (or buckles)	the speed	travel is	IJ27
	in the middle	of travel	constrained
	when energized.	Mechanic-	High force
		ally rigid	required
Push-Pull	Two actuators	The	Not readily	IJ18
	control a shutter.	structure is	suitable for
	One actuator pulls	pinned at	ink jets
	the shutter, and	both ends,	which
	the other pushes	so has a	directly
	it.	high out-of-	push
		plane rigidity	the ink
Curl	A set of actuators	Good fluid	Design	IJ20, IJ42
inwards	curl inwards to	flow to	complexity
	reduce the	the region
	volume of ink	behind the
	that they enclose.	actuator
		increases
		efficiency
Curl	A set of actuators	Relatively	Relatively	IJ43
outwards	curl outwards,	simple	large chip
	pressurizing ink	construction	area
	in a chamber
	surrounding the
	actuators, and
	expelling ink
	from a nozzle in
	the chamber.
Iris	Multiple vanes	High	High	IJ22
	enclose a volume	efficiency	fabrication
	of ink. These	Small chip	complexity
	simultaneously	area	Not suitable
	rotate, reducing		for
	the volume		pigmented
	between the		inks
	vanes.
Acoustic	The actuator	The	Large area	1993
vibration	vibrates at a high	actuator	required for	Hadimioglu
	frequency.	can be	efficient	et al, EUP
		physically	operation at	550,192
		distant from	useful	1993 Elrod
		the ink	frequencies	et al, EUP
			Acoustic	572,220
			coupling and
			crosstalk
			Complex
			drive
			circuitry
			Poor control
			of drop
			volume
			and position
None	In various ink jet	No moving	Various	Silverbrook,
	designs the	parts	other	EP 0771
	actuator does		tradeoffs are	658 A2
	not move.		required to	and related
			eliminate	patent
			moving parts	applications
				Tone-jet

NOZZLE REFILL METHOD

Surface	This is the normal	Fabrication	Low speed	Thermal
tension	way that ink jets	simplicity	Surface	ink jet
	are refilled. After	Operational	tension force	Piezoelectric
	the actuator is	simplicity	relatively	ink jet
	energized, it		small	IJ01-IJ07,
	typically returns		compared to	IJ10-IJ14,
	rapidly to its		actuator	IJ16, IJ20,
	normal position.		force	IJ22-IJ45
	This rapid return		Long refill
	sucks in air		time usually
	through the		dominates
	nozzle opening.		the total
	The ink surface		repetition
	tension at the		rate
	nozzle then exerts
	a small force
	restoring the
	meniscus to a
	minimum area.
	This force refills
	the nozzle.
Shuttered	Ink to the nozzle	High speed	Requires	IJ08, IJ13,
oscillating	chamber is	Low actuator	common ink	IJ15, IJ17,
ink	provided at a	energy, as	pressure	IJ18, IJ19,
pressure	pressure that	the actuator	oscillator	IJ21
	oscillates at twice	need only	May not be
	the drop ejection	open or	suitable for
	frequency. When	close the	pigmented
	a drop is to be	shutter,	inks
	ejected, the	instead
	shutter is opened	of ejecting
	for 3 half cycles:	the ink
	drop ejection,	drop
	actuator return,
	and refill. The
	shutter is then
	closed to prevent
	the nozzle
	chamber
	emptying during
	the next negative
	pressure cycle.
Refill	After the main	High speed,	Requires two	IJ09
actuator	actuator has	as the	independent
	ejected a drop a	nozzle is	actuators
	second (refill)	actively	per nozzle
	actuator is	refilled
	energized. The
	refill actuator
	pushes ink into
	the nozzle
	chamber. The
	refill actuator
	returns slowly, to
	prevent its return
	from emptying
	the chamber
	again.
Positive	The ink is held a	High refill	Surface spill	Silverbrook,
ink	slight positive	rate,	must be	EP 0771
pressure	pressure. After	therefore a	prevented	658 A2
	the ink drop is	high drop	Highly	and related
	ejected, the	repetition	hydrophobic	patent
	nozzle chamber	rate is	print head	applications
	fills quickly as	possible	surfaces are	Alternative
	surface tension		required	for:,
	and ink pressure			IJ01-IJ07,
	both operate to			IJ10-IJ14,
	refill the nozzle.			IJ16, IJ20,
				IJ22-IJ45

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET

Long inlet	The ink inlet	Design	Restricts	Thermal
channel	channel to the	simplicity	refill rate	ink jet
	nozzle chamber is	Operational	May result	Piezoelectric
	made long and	simplicity	in a	ink jet
	relatively narrow,	Reduces	relatively	IJ42, IJ43
	relying on viscous	crosstalk	large chip
	drag to reduce		area
	inlet back-flow.		Only
			partially
			effective
Positive	The ink is under a	Drop	Requires a	Silverbrook,
ink	positive pressure,	selection and	method	EP 0771
pressure	so that in the	separation	(such as a	658 A2
	quiescent state	can forces	nozzle rim	and related
	some of the ink	be reduced	or effective	patent
	drop already	Fast refill	hydro-	applications
	protrudes from	time	phobizing,	Possible
	the nozzle.		or both) to	operation
	This reduces the		prevent	of the
	pressure in the		flooding	following:
	nozzle chamber		of the	IJ01-IJ07,
	which is required		ejection	IJ09-IJ12,
	to eject a certain		surface of	IJ14, IJ16,
	volume of ink.		the print	IJ20, IJ22,
	The reduction in		head.	IJ23-IJ34,
	chamber pressure			IJ36-IJ41,
	results in a			IJ44
	reduction in ink
	pushed out
	through the inlet.
Baffle	One or more	The refill	Design	HP Thermal
	baffles are placed	rate is not	complexity	Ink Jet
	in the inlet ink	as restricted	May increase	Tektronix
	flow. When the	as the long	fabrication	piezoelectric
	actuator is	inlet method.	complexity	ink jet
	energized, the	Reduces	(e.g.
	rapid ink	crosstalk	Tektronix
	movement creates		hot melt
	eddies which		Piezoelectric
	restrict the flow		print heads).
	through the
	inlet. The slower
	refill process is
	unrestricted, and
	does not result in
	eddies.
Flexible	In this method	Significantly	Not	Canon
flap	recently disclosed	reduces	applicable
restricts	by Canon, the	backflow	to most ink
inlet	expanding	for edge-	jet con-
	actuator (bubble)	shooter	figurations
	pushes on a	thermal	Increased
	flexible flap that	ink jet	fabrication
	restricts the inlet.	devices	complexity
			Inelastic
			deformation
			of polymer
			flap results
			in creep over
			extended
			use



Inlet	A filter is located	Additional	Restricts	IJ04, IJ12,
filter	between the ink	advantage	refill rate	IJ24, IJ27,
	inlet and the	of ink	May result	IJ29, IJ30
	nozzle chamber.	filtration	in complex
	The filter has a	Ink filter	construction
	multitude of small	may be
	holes or slots,	fabricated
	restricting ink	with no
	flow. The filter	additional
	also removes	process
	particles which	steps
	may block the
	nozzle.
Small	The ink inlet	Design	Restricts	IJ02, IJ37,
inlet	channel to the	simplicity	refill rate	IJ44
compared	nozzle chamber		May result
to nozzle	has a substantially		in a
	smaller cross		relatively
	section than that		large chip
	of the nozzle,		area
	resulting in easier		Only
	ink egress out of		partially
	the nozzle than		effective
	out of the inlet.
Inlet	A secondary	Increases	Requires	IJ09
shutter	actuator controls	speed of	separate
	the position of a	the inkjet	refill
	shutter, closing	print head	actuator
	off the ink inlet	operation	and drive
	when the main		circuit
	actuator is
	energized.
The inlet	The method	Back-flow	Requires	IJ01, IJ03,
is located	avoids the	problem is	careful	IJ05, IJ06,
behind	problem of inlet	eliminated	design to	IJ07, IJ10,
the ink-	back-flow by		minimize the	IJ11, IJ14,
pushing	arranging the ink-		negative	IJ16, IJ22,
surface	pushing surface		pressure	IJ23, IJ25,
	of the actuator		behind	IJ28, IJ31,
	between the inlet		the paddle	IJ32, IJ33,
	and the nozzle.			IJ34, IJ35,
				IJ36, IJ39,
				IJ40, IJ41
Part of	The actuator and	Significant	Small	IJ07, IJ20,
the	a wall of the ink	reductions in	increase in	IJ26, IJ38
actuator	chamber are	back-flow	fabrication
moves to	arranged so that	can be	complexity
shut off	the motion of the	achieved
the inlet	actuator closes off	Compact
	the inlet.	designs
		possible
Nozzle	In some	Ink back-	None related	Silverbrook,
actuator	configurations of	flow	to ink	EP 0771
does not	ink jet, there is	problem is	back-flow	658 A2
result in	no expansion or	eliminated	on actuation	and related
ink back-	movement of an			patent
flow	actuator which			applications
	may cause ink			Valve-jet
	back-flow			Tone-jet
	through the inlet.

NOZZLE CLEARING METHOD

Normal	All of the nozzles	No added	May not be	Most ink jet
nozzle	are fired	complexity	sufficient	systems
firing	periodically,	on the	to displace	IJ01, IJ02,
	before the ink has	print head	dried	IJ03, IJ04,
	a chance to dry.		ink	IJ05, IJ06,
	When not in use			IJ07, IJ09,
	the nozzles are			IJ10, IJ11,
	sealed (capped)			IJ12, IJ14,
	against air.			IJ16, IJ20,
	The nozzle firing			IJ22, IJ23,
	is usually			IJ24, IJ25,
	performed during			IJ26, IJ27,
	a special clearing			IJ28, IJ29,
	cycle, after first			IJ30, IJ31,
	moving the print			IJ32, IJ33,
	head to a cleaning			IJ34, IJ36,
	station.			IJ37, IJ38,
				IJ39, IJ40,
				IJ41, IJ42,
				IJ43, IJ44,
				IJ45
Extra	In systems which	Can be	Requires	Silverbrook,
power to	heat the ink, but	highly	higher drive	EP 0771
ink heater	do not boil it	effective	voltage for	658 A2
	under normal	if the	clearing	and related
	situations, nozzle	heater is	May require	patent
	clearing can be	adjacent to	larger drive	applications
	achieved by over-	the nozzle	transistors
	powering the
	heater and boiling
	ink at the nozzle.
Rapid	The actuator is	Does not	Effectiveness	May be used
succession	fired in rapid	require	depends	with: IJ01,
of actuator	succession.	extra drive	substantially	IJ02, IJ03,
pulses	In some	circuits	upon the	IJ04, IJ05,
	configurations,	on the	configuration	IJ06, IJ07,
	this may cause	print head	of the ink	IJ09, IJ10,
	heat build-up at	Can be	jet nozzle	IJ11, IJ14,
	the nozzle which	readily		IJ16, IJ20,
	boils the ink,	controlled		IJ22, IJ23,
	clearing the	and initiated		IJ24, IJ25,
	nozzle. In other	by digital		IJ27, IJ28,
	situations, it may	logic		IJ29, IJ30,
	cause sufficient			IJ31, IJ32,
	vibrations to			IJ33, IJ34,
	dislodge clogged			IJ36, IJ37,
	nozzles.			IJ38, IJ39,
				IJ40, IJ41,
				IJ42, IJ43,
				IJ44, IJ45
Extra	Where an actuator	A simple	Not suitable	May be used
power to	is not normally	solution	where there	with: IJ03,
ink	driven to the limit	where	is a hard	IJ09, IJ16,
pushing	of its motion,	applicable	limit to	IJ20, IJ23,
actuator	nozzle clearing		actuator	IJ24, IJ25,
	may be assisted		movement	IJ27, IJ29,
	by providing an			IJ30, IJ31,
	enhanced drive			IJ32, IJ39,
	signal to the			IJ40, IJ41,
	actuator.			IJ42, IJ43,
				IJ44, IJ45
Acoustic	An ultrasonic	A high	High	IJ08, IJ13,
resonance	wave is applied to	nozzle	implement-	IJ15, IJ17,
	the ink chamber.	clearing	ation	IJ18, IJ19,
	This wave is of	capability	cost if	IJ21
	an appropriate	can be	system
	amplitude and	achieved	does not
	frequency to	May be	already
	cause sufficient	implemented	include
	force at the	at very low	an acoustic
	nozzle to clear	cost in	actuator
	blockages. This is	systems
	easiest to achieve	which
	if the ultrasonic	already
	wave is at a	include
	resonant	acoustic
	frequency of the	actuators
	ink cavity.
Nozzle	A microfabricated	Can clear	Accurate	Silverbrook,
clearing	plate is pushed	severely	mechanical	EP 0771
plate	against the	clogged	alignment	658 A2
	nozzles. The plate	nozzles	is required	and related
	has a post for		Moving	patent
	every nozzle. A		parts are	applications
	post moves		required
	through each		There is
	nozzle, displacing		risk of
	dried ink.		damage to
			the nozzles
			Accurate
			fabrication
			is required
Ink	The pressure of	May be	Requires	May be used
pressure	the ink is	effective	pressure	with all
pulse	temporarily	where	pump	IJ series
	increased so that	other	or other	ink jets
	ink streams from	methods	pressure
	all of the nozzles.	cannot	actuator
	This may be used	be used	Expensive
	in conjunction		Wasteful
	with actuator		of ink
	energizing.
Print	A flexible ‘blade’	Effective	Difficult	Many ink jet
head	is wiped across	for planar	to use if	systems
wiper	the print head	print head	print head
	surface. The	surfaces	surface is
	blade is usually	Low cost	non-planar
	fabricated from a		or very
	flexible polymer,		fragile
	e.g. rubber or		Requires
	synthetic		mechanical
	elastomer.		parts
			Blade can
			wear out
			in high
			volume
			print
			systems
Separate	A separate heater	Can be	Fabrication	Can be used
ink	is provided at the	effective	complexity	with many IJ
boiling	nozzle although	where other	series ink
heater	the normal drop	nozzle	jets
	e-ection	clearing
	mechanism does	methods
	not require it.	cannot
	The heaters do	be used
	not require	Can be
	individual	implemented
	drive circuits, as	at no
	many nozzles can	additional
	be cleared	cost in some
	simultaneously,	ink jet con-
	and no imaging is	figurations
	required.

NOZZLEPLATE CONSTRUCTION

Electro-	A nozzle plate is	Fabrication	High	Hewlett
formed	separately	simplicity	temperatures	Packard
nickel	fabricated from		and	Thermal
	electroformed		pressures	Ink jet
	nickel, and		are required
	bonded to the		to bond
	print head chip.		nozzle plate
			Minimum
			thickness
			constraints
			Differential
			thermal
			expansion
Laser	Individual nozzle	No masks	Each hole	Canon
ablated or	holes are ablated	required	must be	Bubblejet
drilled	by an intense UV	Can be	individually	1988 Sercel
polymer	laser in a nozzle	quite fast	formed	et al., SPIE,
	plate, which is	Some	Special	Vol. 998
	typically a	control over	equipment	Excimer
	polymer such as	nozzle	required	Beam
	polyimide or	profile is	Slow where	Applications,
	polysulphone	possible	there	pp. 76-83
		Equipment	are many	1993
		required is	thousands of	Watanabe
		relatively	nozzles per	et al., USP
		low cost	print head	5,208,604
			May produce
			thin burrs at
			exit holes
Silicon	A separate nozzle	High	Two part	K. Bean,
micro-	plate is	accuracy is	construction	IEEE
machined	micromachined	attainable	High cost	Transactions
	from single		Requires	on Electron
	crystal silicon,		precision	Devices,
	and bonded to the		alignment	Vol. ED-25,
	print head wafer.		Nozzles	No. 10,
			may be	1978, pp
			clogged	1185-1195
			by adhesive	Xerox 1990
				Hawkins
				et al., USP
				4,899,181
Glass	Fine glass	No	Very small	1970 Zoltan
capillaries	capillaries are	expensive	nozzle sizes	USP
	drawn from glass	equipment	are difficult	3,683,212
	tubing. This	required	to form
	method has been	Simple to	Not suited
	used for making	make single	for mass
	individual	nozzles	production
	nozzles, but is
	difficult to
	use for bulk
	manufacturing of
	print heads with
	thousands of
	nozzles.
Mono-	The nozzle plate	High	Requires	Silverbrook,
lithic,	is deposited as a	accuracy	sacrificial	EP 0771
surface	layer using	(<1 μm)	layer	658 A2
micro-	standard VLSI	Monolithic	under the	and related
machined	deposition	Low cost	nozzle plate	patent
using	techniques.	Existing	to form	applications
VLSI	Nozzles are	processes	the nozzle	IJ01, IJ02,
litho-	etched in the	can be	chamber	IJ04, IJ11,
graphic	nozzle plate using	used	Surface	IJ12, IJ17,
processes	VLSI lithography		may be	IJ18, IJ20,
	and etching.		fragile	IJ22, IJ24,
			to the	IJ27, IJ28,
			touch	IJ29, IJ30,
				IJ31, IJ32,
				IJ33, IJ34,
				IJ36, IJ37,
				IJ38, IJ39,
				IJ40, IJ41,
				IJ42, IJ43,
				IJ44
Mono-	The nozzle plate	High	Requires	IJ03, IJ05,
lithic,	is a buried etch	accuracy	long etch	IJ06, IJ07,
etched	stop in the wafer.	(<1 μm)	times	IJ08, IJ09,
through	Nozzle chambers	Monolithic	Requires	IJ10, IJ13,
substrate	are etched in the	Low cost	a support	IJ14, IJ15,
	front of the wafer,	No	wafer	IJ16, IJ19,
	and the wafer is	differential		IJ21, IJ23,
	thinned from the	expansion		IJ25, IJ26
	back side.
	Nozzles are then
	etched in the etch
	stop layer.
No nozzle	Various methods	No nozzles	Difficult to	Ricoh 1995
plate	have been tried to	to become	control drop	Sekiya
	eliminate the	clogged	position	et al USP
	nozzles entirely,		accurately	5,412,413
	to prevent nozzle		Crosstalk	1993
	clogging. These		problems	Hadimioglu
	include thermal			et al EUP
	bubble			550,192
	mechanisms and			1993 Elrod
	acoustic lens			et al EUP
	mechanisms			572,220
Trough	Each drop ejector	Reduced	Drop firing	IJ35
	has a trough	manu-	direction is
	through which a	facturing	sensitive to
	paddle moves.	complexity	wicking.
	There is no	Monolithic
	nozzle plate.
Nozzle slit	The elimination	No nozzles	Difficult to	1989 Saito
instead of	of nozzle holes	to become	control drop	et al USP
individual	and replacement	clogged	position	4,799,068
nozzles	by a slit		accurately
	encompassing		Crosstalk
	many actuator		problems
	positions reduces
	nozzle clogging,
	but increases
	crosstalk due to
	ink surface waves

DROP EJECTION DIRECTION

Edge	Ink flow is along	Simple	Nozzles	Canon
(‘edge	the surface of the	construction	limited to	Bubblejet
shooter’)	chip, and ink	No silicon	edge	1979
	drops are ejected	etching	High	Endo et al
	from the chip	required	resolution is	GB patent
	edge.	Good heat	difficult	2,007,162
		sinking via	Fast color	Xerox
		substrate	printing	heater-in-pit
		Mech-	requires one	1990
		anically	print head	Hawkins
		strong	per color	et al USP
		Ease of chip		4,899,181
		handing		Tone-jet
Surface	Ink flow is along	No bulk	Maximum	Hewlett-
(‘roof	the surface of the	silicon	ink flow is	Packard TIJ
shooter’)	chip, and ink	etching	severely	1982 Vaught
	drops are ejected	required	restricted	et al USP
	from the chip	Silicon can		4,490,728
	surface, normal to	make an		IJ02, IJ11,
	the plane of the	effective		IJ12, IJ20,
	chip.	heat sink		IJ22
		Mechanical
		strength
Through	Ink flow is	High ink	Requires	Silverbrook,
chip,	through the chip,	flow	bulk silicon	EP 0771
forward	and ink drops are	Suitable	etching	658 A2
(‘up	ejected from the	for		and related
shooter’)	front surface of	pagewidth		patent
	the chip.	print heads		applications
		High nozzle		IJ04, IJ17,
		packing		IJ18, IJ24,
		density		IJ27-IJ45
		therefore
		low manu-
		facturing
		cost
Through	Ink flow is	High ink	Requires	IJ01, IJ03,
chip,	through the chip,	flow	wafer	IJ05, IJ06,
reverse	and ink drops are	Suitable for	thinning	IJ07, IJ08,
(‘down	ejected from the	pagewidth	Requires	IJ09, IJ10,
shooter’)	rear surface of	print heads	special	IJ13, IJ14,
	the chip.	High nozzle	handling	IJ15, IJ16,
		packing	during	IJ19, IJ21,
		density	manufacture	IJ23, IJ25,
		therefore		IJ26
		low manu-
		facturing
		cost
Through	Ink flow is	Suitable for	Pagewidth	Epson
actuator	through the	piezoelectric	print heads	Stylus
	actuator, which is	print heads	require	Tektronix
	not fabricated as		several	hot melt
	part of the same		thousand	piezoelectric
	substrate as the		connections	ink jets
	drive transistors.		to drive
			circuits
			Cannot be
			manu-
			factured
			in standard
			CMOS fabs
			Complex
			assembly
			required

INK TYPE

Aqueous,	Water based ink	Environ-	Slow drying	Most
dye	which typically	mentally	Corrosive	existing
	contains: water,	friendly	Bleeds on	ink jets
	dye, surfactant,	No odor	paper	All IJ series
	humectant, and		May	ink jets
	biocide.		strikethrough	Silverbrook,
	Modem ink dyes		Cockles	EP 0771
	have high water-		paper	658 A2
	fastness, light			and related
	fastness			patent
				applications
Aqueous,	Water based ink	Environ-	Slow drying	IJ02, IJ04,
pigment	which typically	mentally	Corrosive	IJ21, IJ26,
	contains: water,	friendly	Pigment	IJ27, IJ30
	pigment,	No odor	may clog	Silverbrook,
	surfactant,	Reduced	nozzles	EP 0771
	humectant, and	bleed	Pigment	658 A2
	biocide.	Reduced	may clog	and related
	Pigments have an	wicking	actuator	patent
	advantage in	Reduced	mechanisms	applications
	reduced bleed,	strike-	Cockles	Piezoelectric
	wicking and	through	paper	ink-jets
	strikethrough.			Thermal ink
				jets (with
				significant
				restrictions)
Methyl	MEK is a highly	Very fast	Odorous	All IJ
Ethyl	volatile solvent	drying	Flammable	series
Ketone	used for industrial	Prints on		ink jets
(MEK)	printing on	various
	difficult surfaces	substrates
	such as aluminum	such as
	cans.	metals and
		plastics
Alcohol	Alcohol based	Fast drying	Slight odor	All IJ
(ethanol,	inks can be used	Operates at	Flammable	series
2-butanol,	where the printer	sub-freezing		ink jets
and	must operate at	temperatures
others)	temperatures	Reduced
	below the	paper cockle
	freezing point	Low cost
	of water. An
	example of this
	is in-camera
	consumer
	photographic
	printing.
Phase	The ink is solid	No drying	High	Tektronix
change	at room	time—ink	viscosity	hot melt
(hot melt)	temperature,	instantly	Printed ink	piezoelectric
	and is melted in	freezes on	typically has	ink jets
	the print head	the print	a ‘waxy’ feel	1989 Nowak
	before jetting.	medium	Printed	USP
	Hot melt inks are	Almost any	pages may	4,820,346
	usually wax	print	‘block’	All IJ series
	based, with a	medium can	Ink	ink jets
	melting point	be used	temperature
	around 80° C.	No paper	may be
	After jetting	cockle	above the
	the ink freezes	occurs	curie point
	almost instantly	No wicking	of permanent
	upon contacting	occurs	magnets
	the print medium	No bleed	Ink heaters
	or a transfer	occurs	consume
	roller.	No	power
		strikethrough	Long warm
		occurs	up time
Oil	Oil based inks are	High	High	All IJ
	extensively used	solubility	viscosity:	series
	in offset printing,	medium for	this is a	ink jets
	They have	some dyes	significant
	advantages in	Does not	limitation
	improved	cockle	for use in
	characteristics on	paper	ink jets,
	paper (especially	Does not	which
	no wicking or	wick through	usually
	cockle). Oil	paper	require
	soluble dies and		a low
	pigments are		viscosity.
	required.		Some short
			chain and
			multi-
			branched
			oils have a
			sufficiently
			low
			viscosity.
			Slow drying

Micro-	A microemulsion	Stops ink	Viscosity	All IJ
emulsion	is a stable, self	bleed	higher than	series
	forming emulsion	High dye	water	ink jets
	of oil, water, and	solubility	Cost is
	surfactant. The	Water,	slightly
	characteristic	oil, and	higher than
	drop size is less	amphiphilic	water
	than 100 nm, and	soluble	based ink
	is determined by	dies can	High
	the preferred	be used	surfactant
	curvature of the	Can stabilize	con-
	surfactant.	pigment	centration
		suspensions	required
			(around 5%)

Claims

We claim:

1. A method of image enhancement of a sensed image taken with a digital camera, said digital camera being hand held and including an area image sensor, internal page width ink jet printer, processor means for processing an output of said area image sensor in accordance with processing rules, and a print roll including print media and printing ink for printing out a processed image on said print media, said digital camera further including an auto exposure setting means, said method comprising the step of utilising exposure setting information from said auto exposure setting means to process said sensed image in accordance with said processing rules.

2. A method as claimed in claim 1 wherein said utilising step comprises utilising the auto exposure setting from said auto exposure setting means to determine a re-mapping of colours within said image so as to produce an amended image having colours within an image transformed to take account of said auto exposure setting.

3. A method as claimed in claim 2 wherein said processing comprises re-mapping image colours so they appear deeper and richer when said auto exposure setting indicates low light conditions.

4. A method as claimed in claim 3 wherein said processing step comprises re-mapping image colours to be brighter and more saturated when said auto exposure setting indicates bright light conditions.

5. A method as claimed in claim 1 wherein said utilising step includes adding exposure specific graphics to said image.

6. A method of image enhancement of a sensed image taken with a digital camera, including an auto exposure setting means, said method comprising the step of utilising the auto exposure setting from said auto exposure setting means to process said sensed image to add exposure specific graphics to said image.