Arrangement of usage indicator in a recyclable, digital camera

Abstract

A recyclable, one-time use print on demand, digital camera comprises an image sensor device for sensing an image. A processor processes the image sensed by the image sensor device. The camera includes a supply of print media on to which an image processed by the processor is printed. A printhead is provided for printing said sensed image on the print media. An indicator for indicating usage of the camera is arranged within a housing of the camera. A separating device separates a part of the print media on to which an image has been printed from a remainder of the supply of print media. The separating device acts on the indicator for changing the indication of usage as part of the operation of separating the part of the print media from the remainder of the supply of the print media.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

This invention relates to a recyclable digital camera. More particularly, the invention relates to a recyclable, one-time use, print on demand, digital camera. More specifically, the invention relates to an arrangement for indicating use of such a camera.

BACKGROUND OF THE INVENTION

Recently, the concept of a “single use” disposable camera has become an increasingly popular consumer item. Disposable camera systems presently on the market normally includes an internal film roll and a simplified gearing mechanism for traversing the film roll across an imaging system including a shutter and lensing system. The user, after utilising a single film roll returns the camera system to a film development center for processing. The film roll is taken out of the camera system and processed and the prints returned to the user. The camera system is then able to be re-manufactured through the insertion of a new film roll into the camera system, the replacement of any worn or wearable parts and the re-packaging of the camera system in accordance with requirements. In this way, the concept of a single use “disposable” camera is provided to the consumer.

Recently, a camera system has been proposed by the present applicant which provides for a handheld camera device having an internal printhead, image sensor and processing means such that images sensed by the image sensing means, are processed by the processing means and adapted to be instantly printed out by the printing means on demand. The proposed camera system further discloses a system of internal “print rolls” carrying print media such as film on to which images are to be printed in addition to ink to supply to the printing means for the printing process. The print roll is further disclosed to be detachable and replaceable within the camera system.

Unfortunately, such a system is likely to only be constructed at a substantial cost and it would be desirable to provide for a more inexpensive form of instant camera system which maintains a substantial number of the quality aspects of the aforementioned arrangement.

In particular, in any “disposable camera” it would be desirable to provide for a simple and rapid form of replenishment of the consumable portions in any disposable camera so that the disposable camera can be readily and rapidly serviced by replenishment and returned to the market place.

It would be further desirable to provide for a simplified form of automated picture counting in a disposable camera system.

SUMMARY OF THE INVENTION

According to the invention, there is provided a recyclable, one-time use, print on demand, digital camera comprising

an image sensor device for sensing an image;

a processing means for processing an image sensed by the image sensor device;

a supply of print media on to which an image processed by the processing means is printed;

a print head for printing said sensed image on the print media;

an indicating means for indicating usage of the camera; and

a separating means for separating a part of the print media on to which an image has been printed from a remainder of the supply of print media, the separating means acting on the indicating means for changing said indication of usage as part of the operation of separating said part from the remainder of the supply of the print media.

The print head may be a pagewidth print head which has a length corresponding to one of a length and width of an image to be printed. Generally, the print head will have a length corresponding to the width of an image to be printed.

The supply of print media may move past the print head in a direction substantially normal to a longitudinal axis of the print head, the separating means being displaceable in a direction parallel to said longitudinal axis for separating said part of the supply of print media from the remainder of the supply of print media.

The separating means may be in the form of a cutting element which bears against a bearing surface defined by a chassis of the camera to effect separation of said part from the remainder of the supply of print head.

Further, the indicating means may be in the form of a wheel rotatably arranged on the chassis. The wheel may have numbers arranged thereon which are visible through a window in a housing of the camera. The separating means may then act on the wheel either to decrement or increment the visible number to show the number of images remaining or the number of images printed, as the case may be.

The separating means may thus include an engaging formation which engages a complementary formation of the indicating means to change the indication of usage displayed by the indicating means as the separating means moves along its path of travel, the engaging formation and the complementary formation being such that the separating means causes a change in the indication of usage in one direction of traversal of the path of travel of the separating means but does not cause a change in said indication of usage in an opposite direction of traversal of the path of travel.

More particularly, the cutting wheel constituting the separating means may be arranged on a carrier. The carrier may have a pawl projecting therefrom, the pawl being the engaging formation. The wheel of the indicating means may have ratchet teeth arranged about its circumference to be engaged by the pawl as the separating means traverses its path of travel.

Preferably, the separating means causes a change in the indication of usage as the separating means returns to its rest position after completion of a separating operation.

The supply of print media may be replenishable, the supply of print media being arranged on the chassis with a removable print media path defining means, in the form of a platten, displaceably arranged relative to the chassis. The indicating means may be arranged on the chassis, as described above, with the separating means being carried on the print media path defining means.

BRIEF DESCRIPTION OF THE 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 the accompanying drawings in which:

FIG. 1 illustrates a side front perspective view of the assembled camera of the preferred embodiment;

FIG. 2 illustrates a back side perspective view, partly exploded, of the preferred embodiment;

FIG. 3 is a side perspective view of the chassis of the preferred embodiment;

FIG. 4 is a side perspective view of the chassis illustrating the insertion of the electric motors;

FIG. 5 is an exploded perspective of the ink supply mechanism of the preferred embodiment;

FIG. 6 is a side perspective of the assembled form of the ink supply mechanism of the preferred embodiment;

FIG. 7 is a front perspective view of the assembled form of the ink supply mechanism of the preferred embodiment;

FIG. 8 is an exploded perspective of the platen unit of the preferred embodiment;

FIG. 9 is a side perspective view of the assembled form of the platen unit;

FIG. 10 is also a side perspective view of the assembled form of the platen unit;

FIG. 11 is an exploded perspective unit of a printhead recapping mechanism of the preferred embodiment;

FIG. 12 is a close up exploded perspective of the recapping mechanism of the preferred embodiment;

FIG. 13 is an exploded perspective of the ink supply cartridge of the preferred embodiment;

FIG. 14 is a close up perspective, partly in section, of the internal portions of the ink supply cartridge in an assembled form;

FIG. 15 is a schematic block diagram of one form of chip layer of the image capture and processing chip of the preferred embodiment;

FIG. 16 is an exploded perspective illustrating the assembly process of the preferred embodiment;

FIG. 17 illustrates a front exploded perspective view of the assembly process of the preferred embodiment

FIG. 18 illustrates a side perspective view of the assembly process of the preferred embodiment;

FIG. 19 illustrates a side perspective view of the assembly process of the preferred embodiment;

FIG. 20 is a perspective view illustrating the insertion of the platen unit in the preferred embodiment;

FIG. 21 illustrates the interconnection of the electrical components of the preferred embodiment;

FIG. 22 illustrates the process of assembling the preferred embodiment; and

FIG. 23 is a perspective view further illustrating the assembly process of the preferred embodiment.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

Turning initially simultaneously to FIG. 1 , and FIG. 2 there is illustrated perspective views of an assembled camera constructed in accordance with the preferred embodiment with FIG. 1 showing a front side perspective view and FIG. 2 showing a back side perspective view. The camera I includes a paper or plastic film jacket 2 which can include simplified instructions 3 for the operation of the camera system 1 . The camera system 1 includes a first “take” button 4 which is depressed to capture an image. The captured image is output via output slot 6 . A further copy of the image can be obtained through depressing a second “printer copy” button 7 whilst an LED light 5 is illuminated. The camera system also provides the usual view finder 8 in addition to a CCD image capture/lensing system 9 .

The camera system 1 provides for a standard number of output prints after which the camera system 1 ceases to function. A prints left indicator slot 10 is provided to indicate the number of remaining prints. A refund scheme at the point of purchase is assumed to be operational for the return of used camera systems for recycling.

Turning now to FIG. 3 , the assembly of the camera system is based around an internal chassis 12 which can be a plastic injection molded part. A pair of paper pinch rollers 28 , 29 utilized for decurling are snap fitted into corresponding frame holes eg. 26 , 27 .

As shown in FIG. 4 , the chassis 12 includes a series of mutually opposed prongs eg. 13 , 14 into which is snapped fitted a series of electric motors 16 , 17 . The electric motors 16 , 17 can be entirely standard with the motor 16 being of a stepper motor type and include a cogged end portion 19 , 20 for driving a series of gear wheels. A first set of gear wheels is provided for controlling a paper cutter mechanism and a second set is provided for controlling print roll movement.

Turning next to FIGS. 5 to 7 , there is illustrated an ink supply mechanism 40 utilized in the camera system. FIG. 5 illustrates a back exploded perspective view, FIG. 6 illustrates a back assembled view and FIG. 7 illustrates a front assembled view. The ink supply mechanism 40 is based around an ink supply cartridge 42 which contains printer ink and a printhead mechanism for printing out pictures on demand. The ink supply cartridge 42 includes a side aluminum strip 43 which is provided as a shear strip to assist in cutting images from a paper roll.

A dial mechanism 44 is provided for indicating the number of “prints left”. The dial mechanism 44 is snap fitted through a corresponding mating portion 46 so as to be freely rotatable.

As shown in FIG. 6 , the printhead includes a flexible PCB strip 47 which interconnects with the printhead and provides for control of the printhead. The interconnection between the flexible PCB strip and an image sensor and printhead chip can be via Tape Automated Bonding (TAB) Strips 51 , 58 . A molded aspherical lens and aperture shim 50 ( FIG. 5 ) is also provided for imaging an image onto the surface of the image sensor chip normally located within cavity 53 and a light box module or hood 52 is provided for snap fitting over the cavity 53 so as to provide for proper light control. A series of decoupling capacitors e.g. 34 can also be provided. Further, a plug 121 ( FIG. 7 ) is provided for re-plugging ink holes after refilling. A series of guide prongs e.g. 55 - 57 are further provided for guiding the flexible PCB strip 47 .

The ink supply mechanism 40 interacts with a platen unit 60 which guides print media under a printhead located in the ink supply mechanism. FIG. 8 shows an exploded view of the platen unit 60 , while FIGS. 9 and 10 show assembled views of the platen unit 60 . The platen unit 60 includes a first pinch roller 61 which is snap fitted to one side of a platen base 62 . Attached to a second side of the platen base 62 is a cutting mechanism 63 which traverses the platen by means of a rod 64 having a screwed thread which is rotated by means of cogged wheel 65 which is also fitted to the platen 62 . The screwed thread engages a block 67 which includes a cutting wheel 68 fastened via a fastener 69 . Also mounted to the block 67 is a counter actuator which includes a prong 71 . The prong 71 acts to rotate the dial mechanism 44 of FIG. 6 upon the return traversal of the cutting wheel. As shown previously in FIG. 6 , the dial mechanism 44 includes a cogged surface which interacts with pawl lever 73 , thereby maintaining a count of the number of photographs taken on the surface of dial mechanism 44 . The cutting mechanism 63 is inserted into the platen base 62 by means of a snap fit via receptacle 74 .

The platen 62 includes an internal re-capping mechanism 80 for re-capping the printhead when not in use. The re-capping mechanism 80 includes a sponge portion 81 and is operated via a solenoid coil so as to provide for recapping of the printhead. In the preferred embodiment, there is provided an inexpensive form of printhead re-capping mechanism provided for incorporation into a handheld camera system so as to provide for printhead re-capping of an inkjet printhead.

FIG. 11 illustrates an exploded view of the recapping mechanism 80 whilst FIG. 12 illustrates a close up of the end portion thereof. The re-capping mechanism 80 is structured around a solenoid including a 16 turn coil 75 which can comprise insulated wire. The coil 75 is turned around a first stationary solenoid arm 76 which is mounted on a bottom surface of the platen 62 ( FIG. 8 ) and includes a post portion 77 to magnify effectiveness of operation. The arm 76 can comprise a ferrous material.

A second moveable arm 78 of the solenoid actuator is also provided, the arm 78 is moveable and is also made of ferrous material. Mounted on the arm is a sponge portion surrounded by an elastomer strip 79 . The elastomer strip 79 is of a generally arcuate cross-section and acts as a leaf spring against the surface of the printhead ink supply cartridge 42 ( FIG. 5 ) so as to provide for a seal against the surface of the printhead ink supply cartridge 42 . In the quiescent position elastomer spring units 87 , 88 act to resiliently deform the elastomer seal 79 against the surface of the ink supply unit 42 .

When it is desired to operate the printhead unit, upon the insertion of paper, the solenoid coil 75 is activated so as to cause the arm 78 to move down to be adjacent to the end plate 76 . The arm 78 is held against end plate 76 while the printhead is printing by means of a small “keeper current” in coil 75 . Simulation results indicate that the keeper current can be significantly less than the actuation current. Subsequently, after photo printing, the paper is guillotined by the cutting mechanism 63 of FIG. 8 acting against Aluminum Strip 43 of FIG. 5 , and rewound so as to clear the area of the re-capping mechanism 80 . Subsequently, the current is turned off and springs 87 , 88 return the arm 78 so that the elastomer seal is again resting against the printhead ink supply cartridge.

It can be seen that the preferred embodiment provides for a simple and inexpensive means of re-capping a printhead through the utilization of a solenoid type device having a long rectangular form. Further, the preferred embodiment utilizes minimal power in that currents are only required whilst the device is operational and additionally, only a low keeper current is required whilst the printhead is printing.

Turning next to FIGS. 13 and 14 , FIG. 13 illustrates an exploded perspective of the ink supply cartridge 42 whilst FIG. 14 illustrates a close up sectional view of a bottom of the ink supply cartridge 42 with the printhead unit in place. The ink supply cartridge 42 is based around a pagewidth printhead 102 which comprises a long slither of silicon having a series of holes etched on the back surface for the supply of ink to a front surface of the silicon wafer for subsequent ejection via a micro electro mechanical system. The form of ejection can be many different forms such as those set out in the tables below.

Of course, many other inkjet technologies, as referred to the attached tables below, can also be utilized when constructing a printhead unit 102 . The fundamental requirement of the ink supply cartridge 42 being the supply of ink to a series of color channels etched through the back surface of the printhead 102 . In the description of the preferred embodiment, it is assumed that a three color printing process is to be utilized so as to provide full color picture output. Hence, the ink supply unit 42 includes three ink supply reservoirs being a cyan reservoir 104 , a magenta reservoir 105 and a yellow reservoir 106 . Each of these reservoirs is configured to store ink and includes a corresponding sponge type material 107 - 109 which assists in stabilizing ink within the corresponding ink channel and therefore preventing the ink from sloshing back and forth when the printhead is utilized in a handheld camera system. The reservoirs 104 , 105 , 106 are formed through the mating of first exterior plastic piece 110 mating with a second base piece) 111 .

A first end of the base piece 111 includes a series of air inlets 113 - 115 . The air inlets lead to a corresponding winding channel which is hydrophobically treated so as to act as an ink repellent and therefore repel any ink that may flow along the air inlet channel. The air inlet channel further takes a convoluted path further assisting in resisting any ink flow out of the chambers 104 - 106 . An adhesive tape portion 117 is provided for sealing the channels within end portion 118 .

At the top end, there is included a series of refill holes for refilling corresponding ink supply chambers 104 , 105 , 106 . A plug 121 is provided for sealing the refill holes.

Turning now to FIG. 14 , there is illustrated a close up perspective view, partly in section, through the ink supply cartridge 42 of FIG. 13 when formed as a unit. The ink supply cartridge includes the three color ink reservoirs 104 , 105 , 106 which supply ink to different portions of the back surface of printhead 102 which includes a series of apertures 128 defined therein for carriage of the ink to the front surface.

The ink supply unit includes two guide walls 124 , 125 which separate the various ink chambers and are tapered into an end portion abutting the surface of the printhead 102 . The guide walls are further mechanically supported at regular spaces by block portions 126 which are placed at regular intervals along the length of the printhead supply unit. The block portions 126 leave space at portions close to the back of printhead 102 for the flow of ink around the back surface thereof.

The printhead supply unit is preferably formed from a multi-part plastic injection mold and the mold pieces e.g. 110 , 111 ( FIG. 13 ) snap together around the sponge pieces 107 , 108 , 109 . Subsequently, a syringe type device can be inserted in the ink refill holes and the ink reservoirs filled with ink with the air flowing out of the air outlets 113 - 115 . Subsequently, the adhesive tape portion 117 and plug 121 are attached and the printhead tested for operation capabilities. Subsequently, the ink supply cartridge 42 can be readily removed for refilling by means of removing the ink supply cartridge, performing a washing cycle, and then utilizing the holes for the insertion of a refill syringe filled with ink for refilling the ink chamber before returning the ink supply cartridge 42 to a camera.

Turning now to FIG. 15 , there is shown an example layout of the Image Capture and Processing Chip (ICP) 48 .

The Image Capture and Processing Chip 48 provides most of the electronic functionality of the camera with the exception of the printhead chip. The chip 48 is a highly integrated system. It combines CMOS image sensing, analog to digital conversion, digital image processing, DRAM storage, ROM, and miscellaneous control functions in a single chip.

The chip is estimated to be around 32 mm 2 using a leading edge 0.18 micron CMOS/DRAM/APS process. The chip size and cost can scale somewhat with Moore's law, but is dominated by a CMOS active pixel sensor array 201 , so scaling is limited as the sensor pixels approach the diffraction limit.

The ICP 48 includes CMOS logic, a CMOS image sensor, DRAM, and analog circuitry. A very small amount of flash memory or other non-volatile memory is also preferably included for protection against reverse engineering.

Alternatively, the ICP can readily be divided into two chips: one for the CMOS imaging array, and the other for the remaining circuitry. The cost of this two chip solution should not be significantly different than the single chip ICP, as the extra cost of packaging and bond-pad area is somewhat cancelled by the reduced total wafer area requiring the color filter fabrication steps.

The ICP preferably contains the following functions:

Function
1.5 megapixel image sensor
Analog Signal Processors
Image sensor column decoders
Image sensor row decoders
Analogue to Digital Conversion (ADC)
Column ADC's
Auto exposure
12 Mbits of DRAM
DRAM Address Generator
Color interpolator
Convolver
Color ALU
Halftone matrix ROM
Digital halftoning
Printhead interface
8 bit CPU core
Program ROM
Flash memory
Scratchpad SRAM
Parallel interface (8 bit)
Motor drive transistors (5)
Clock PLL
JTAG test interface
Test circuits
Busses
Bond pads

The CPU, DRAM, Image sensor, ROM, Flash memory, Parallel interface, JTAG interface and ADC can be vendor supplied cores. The ICP is intended to run on 1.5 V to minimize power consumption and allow convenient operation from two AA type battery cells.

FIG. 15 illustrates a layout of the ICP 48 . The ICP 48 is dominated by the imaging array 201 , which consumes around 80% of the chip area. The imaging array is a CMOS 4 transistor active pixel design with a resolution of 1,500×1,000. The array can be divided into the conventional configuration, with two green pixels, one red pixel, and one blue pixel in each pixel group. There are 750×500 pixel groups in the imaging array.

The latest advances in the field of image sensing and CMOS image sensing in particular can be found in the October, 1997 issue of IEEE Transactions on Electron Devices and, in particular, pages 1689 to 1968. Further, a specific implementation similar to that disclosed in the present application is disclosed in Wong et. al, “CMOS Active Pixel Image Sensors Fabricated Using a 1.8 V, 0.25 μm CMOS Technology”, IEDM 1996, page 915.

The imaging array uses a 4 transistor active pixel design of a standard configuration. To minimize chip area and therefore cost, the image sensor pixels should be as small as feasible with the technology available. With a four transistor cell, the typical pixel size scales as 20 times the lithographic feature size. This allows a minimum pixel area of around 3.6 μm×3.6 μm. However, the photosite must be substantially above the diffraction limit of the lens. It is also advantageous to have a square photosite, to maximize the margin over the diffraction limit in both horizontal and vertical directions. In this case, the photosite can be specified as 2.5 μmμ2.5 μm. The photosite can be a photogate, pinned photodiode, charge modulation device, or other sensor.

The four transistors are packed as an ‘L’ shape, rather than a rectangular region, to allow both the pixel and the photosite to be square. This reduces the transistor packing density slightly, increasing pixel size. However, the advantage in avoiding the diffraction limit is greater than the small decrease in packing density.

The transistors also have a gate length which is longer than the minimum for the process technology. These have been increased from a drawn length of 0.18 micron to a drawn length of 0.36 micron. This is to improve the transistor matching by making the variations in gate length represent a smaller proportion of the total gate length.

The extra gate length, and the ‘L’ shaped packing, mean that the transistors use more area than the minimum for the technology. Normally, around 8 μm 2 would be required for rectangular packing. Preferably, 9.75 μm 2 has been allowed for the transistors.

The total area for each pixel is 16 μm 2 , resulting from a pixel size of 4 μm×4 μm. With a resolution of 1,500×1,000, the area of the imaging array 101 is 6,000 μm×4,000 μm, or 24 mm 2 .

The presence of a color image sensor on the chip affects the process required in two major ways:

The CMOS fabrication process should be optimized to minimize dark current.

Color filters are required. These can be fabricated using dyed photosensitive polyimides, resulting in an added process complexity of three spin coatings, three photolithographic steps, three development steps, and three hardbakes.

There are 15,000 analog signal processors (ASPs) 205 , one for each of the columns of the sensor. The ASPs amplify the signal, provide a dark current reference, sample and hold the signal, and suppress the fixed pattern noise (FPN).

There are 375 analog to digital converters 206 , one for each four columns of the sensor array. These may be delta-sigma or successive approximation type ADC's. A row of low column ADC's are used to reduce the conversion speed required, and the amount of analog signal degradation incurred before the signal is converted to digital. This also eliminates the hot spot (affecting local dark current) and the substrate coupled noise that would occur if a single high speed ADC was used. Each ADC also has two four bit DAC's which trim the offset and scale of the ADC to further reduce FPN variations between columns. These DAC's are controlled by data stored in flash memory during chip testing.

The column select logic 204 is a 1:1500 decoder which enables the appropriate digital output of the ADCs onto the output bus. As each ADC is shared by four columns, the least significant two bits of the row select control 4 input analog multiplexors.

A row decoder 207 is a 1:1000 decoder which enables the appropriate row of the active pixel sensor array. This selects which of the 1000 rows of the imaging array is connected to analog signal processors. As the rows are always accessed in sequence, the row select logic can be implemented as a shift register.

An auto exposure system 208 adjusts the reference voltage of the ADC 205 in response to the maximum intensity sensed during the previous frame period. Data from the green pixels is passed through a digital peak detector. The peak value of the image frame period before capture (the reference frame) is provided to a digital to analogue converter(DAC), which generates the global reference voltage for the column ADCs. The peak detector is reset at the beginning of the reference frame. The minimum and maximum values of the three RGB color components are also collected for color correction.

The second largest section of the chip is consumed by a DRAM 210 used to hold the image. To store the 1,500×1,000 image from the sensor without compression, 1.5 Mbytes of DRAM 210 are required. This equals 12 Mbits, or slightly less than 5% of a 256 Mbit DRAM. The DRAM technology assumed is of the 256 Mbit generation implemented using 0.18 μm CMOS.

Using a standard 8F cell, the area taken by the memory array is 3.11 mm 2 . When row decoders, column sensors, redundancy, and other factors are taken into account, the DRAM requires around 4 mm 2 .

This DRAM 210 can be mostly eliminated if analog storage of the image signal can be accurately maintained in the CMOS imaging array for the two seconds required to print the photo. However, digital storage of the image is preferable as it is maintained without degradation, is insensitive to noise, and allows copies of the photo to be printed considerably later.

A DRAM address generator 211 provides the write and read addresses to the DRAM 210 . Under normal operation, the write address is determined by the order of the data read from the CMOS image sensor 201 . This will typically be a simple raster format. However, the data can be read from the sensor 201 in any order, if matching write addresses to the DRAM are generated. The read order from the DRAM 210 will normally simply match the requirements of a color interpolator and the printhead. As the cyan, magenta, and yellow rows of the printhead are necessarily offset by a few pixels to allow space for nozzle actuators, the colors are not read from the DRAM simultaneously. However, there is plenty of time to read all of the data from the DRAM many times during the printing process. This capability is used to eliminate the need for FIFOs in the printhead interface, thereby saving chip area. All three RGB image components can be read from the DRAM each time color data is required. This allows a color space converter to provide a more sophisticated conversion than a simple linear RGB to CMY conversion.

Also, to allow two dimensional filtering of the image data without requiring line buffers, data is re-read from the DRAM array.

The address generator may also implement image effects in certain models of camera. For example, passport photos are generated by a manipulation of the read addresses to the DRAM. Also, image framing effects (where the central image is reduced), image warps, and kaleidoscopic effects can all be generated by manipulating the read addresses of the DRAM.

While the address generator 211 may be implemented with substantial complexity if effects are built into the standard chip, the chip area required for the address generator is small, as it consists only of address counters and a moderate amount of random logic.

A color interpolator 214 converts the interleaved pattern of red, 2×green, and blue pixels into RGB pixels. It consists of three 8 bit adders and associated registers. The divisions are by either 2 (for green) or 4 (for red and blue) so they can be implemented as fixed shifts in the output connections of the adders.

A convolver 215 is provided as a sharpening filter which applies a small convolution kernel (5×5) to the red, green, and blue planes of the image. The convolution kernel for the green plane is different from that of the red and blue planes, as green has twice as many samples. The sharpening filter has five functions:

To improve the color interpolation from the linear interpolation provided by the color interpolator, to a close approximation of a sinc interpolation.

To compensate for the image ‘softening’ which occurs during digitization.

To adjust the image sharpness to match average consumer preferences, which are typically for the image to be slightly sharper than reality. As the single use camera is intended as a consumer product, and not a professional photographic products, the processing can match the most popular settings, rather than the most accurate.

To suppress the sharpening of high frequency (individual pixel) noise. The function is similar to the ‘unsharp mask’ process.

To antialias Image Warping.

These functions are all combined into a single convolution matrix. As the pixel rate is low (less than 1 Mpixel per second) the total number of multiplies required for the three color channels is 56 million multiplies per second. This can be provided by a single multiplier. Fifty bytes of coefficient ROM are also required.

A color ALU 113 combines the functions of color compensation and color space conversion into the one matrix multiplication, which is applied to every pixel of the frame. As with sharpening, the color correction should match the most popular settings, rather than the most accurate.

A color compensation circuit of the color ALU provides compensation for the lighting of the photo. The vast majority of photographs are substantially improved by a simple color compensation, which independently normalizes the contrast and brightness of the three color components.

A color look-up table (CLUT) 212 is provided for each color component. These are three separate 256×8 SRAMs, requiring a total of 6,144 bits. The CLUTs are used as part of the color correction process. They are also used for color special effects, such as stochastically selected “wild color” effects.

A color space conversion system of the color ALU converts from the RGB color space of the image sensor to the CMY color space of the printer. The simplest conversion is a 1's complement of the RGB data. However, this simple conversion assumes perfect linearity of both color spaces, and perfect dye spectra for both the color filters of the image sensor, and the ink dyes. At the other extreme is a tri-linear interpolation of a sampled three dimensional arbitrary transform table. This can effectively match any non-linearity or differences in either color space. Such a system is usually necessary to obtain good color space conversion when the print engine work on the color electrophotographic principle.

However, since the non-linearity of a halftoned ink jet output is very small, a simpler system can be used. A simple matrix multiplier can provide excellent results. This requires nine multiplications and six additions per contone pixel. However, since the contone pixel rate is low (less than 1 Mpixel/sec) these operations can share a single multiplier and adder. The multiplier and adder are used in a color ALU which is shared with the color compensation function.

Digital halftoning can be performed as a dispersed dot ordered dither using a stochastic optimized dither cell. A halftone matrix ROM 116 is provided for storing dither cell coefficients. A dither cell size of 32×32 is adequate to ensure that the cell repeat cycle is not visible. The three colors—cyan, magenta, and yellow—are all dithered using the same cell, to ensure maximum co-positioning of the ink dots. This minimizes ‘muddying’ of the mid-tones which results from bleed of dyes from one dot to adjacent dots while still wet. The total ROM size required is 1 KByte, as the one ROM is shared by the halftoning units for each of the three colors.

The digital halftoning used is dispersed dot ordered dither with stochastic optimized dither matrix. While dithering does not produce an image quite as ‘sharp’ as error diffusion, it does produce a more accurate image with fewer artifacts. The image sharpening produced by error diffusion is artificial, and less controllable and accurate than ‘unsharp mask’ filtering performed in the contone domain. The high print resolution (1,600 dpi×1,600 dpi) results in excellent quality when using a well formed stochastic dither matrix.

Digital halftoning is performed by a digital halftoning unit 217 using a simple comparison between the contone information from the DRAM 210 and the contents of the dither matrix 216 . During the halftone process, the resolution of the image is changed from the 250 dpi of the captured contone image to the 1,600 dpi of the printed image. Each contone pixel is converted to an average of 40.96 halftone dots.

The ICP incorporates a 16 bit microcontroller CPU core 219 to run the miscellaneous camera functions, such as reading the buttons, controlling the motor and solenoids, setting up the hardware, and authenticating the refill station. The processing power required by the CPU is very modest, and a wide variety of processor cores can be used. As the entire CPU program is run from a small ROM 220 . Program compatibility between camera versions is not important, as no external programs are run. A 2 Mbit (256 Kbyte) program and data ROM 220 is included on chip. Most of this ROM space is allocated to data for outline graphics and fonts for specialty cameras. The program requirements are minor. The single most complex task is the encrypted authentication of the refill station. The ROM requires a single transistor per bit.

A Flash memory 221 may be used to store a 128 bit authentication code. This provides higher security than storage of the authentication code in ROM, as reverse engineering can be made essentially impossible. The Flash memory is completely covered by third level metal, making the data impossible to extract using scanning probe microscopes or electron beams. The authentication code is stored in the chip when manufactured. At least two other Flash bits are required for the authentication process: a bit which locks out reprogramming of the authentication code, and a bit which indicates that the camera has been refilled by an authenticated refill station. The flash memory can also be used to store FPN correction data for the imaging array. Additionally, a phase locked loop resealing parameter is provided for scaling the clocking cycle to an appropriate correct time. The clock frequency does not require crystal accuracy since no date functions are provided. To eliminate the cost of a crystal, an on chip oscillator with a phase locked loop 224 is used. As the frequency of an on-chip oscillator is highly variable from chip to chip, the frequency ratio of the oscillator to the PLL is digitally trimmed during initial testing. The value is stored in Flash memory 221 . This allows the clock PLL to control the ink-jet heater pulse width with sufficient accuracy.

A scratchpad SRAM is a small static RAM 222 with a 6T cell. The scratchpad provided temporary memory for the 16 bit CPU. 1024 bytes is adequate.

A printhead interface 223 formats the data correctly for the printhead. The printhead interface also provides all of the timing signals required by the printhead. These timing signals may vary depending upon temperature, the number of dots printed simultaneously, the print medium in the print roll, and the dye density of the ink in the print roll.

The following is a table of external connections to the printhead interface:

Connection	Function	Pins
DataBits[0-7]	Independent serial data to the eight segments of the printhead	8
BitClock	Main data clock for the printhead	1
ColorEnable[0-2]	Independent enable signals for the CMY actuators, allowing different	3
	pulse times for each color.
BankEnable[0-1]	Allows either simultaneous or interleaved actuation of two banks of	2
	nozzles. This allows two different print speed/power consumption
	tradeoffs
NozzleSelect[0-4]	Selects one of 32 banks of nozzles for simultaneous actuation	5
ParallelXferClock	Loads the parallel transfer register with the data from the shift registers	1
Total		20

The printhead utilized is composed of eight identical segments, each 1.25 cm long. There is no connection between the segments on the printhead chip. Any connections required are made in the external TAB bonding film, which is double sided. The division into eight identical segments is to simplify lithography using wafer steppers. The segment width of 1.25 cm fits easily into a stepper field. As the printhead chip is long and narrow (10 cm×0.3 mm), the stepper field contains a single segment of 32 printhead chips. The stepper field is therefore 1.25 cm×1.6 cm. An average of four complete printheads are patterned in each wafer step.

A single BitClock output line connects to all 8 segments on the printhead. The 8 DataBits lines lead one to each segment, and are clocked in to the 8 segments on the printhead simultaneously (on a BitClock pulse). For example, dot 0 is transferred to segment 0 , dot 750 is transferred to segment 1 , dot 1500 to segment 2 etc simultaneously.

The ParallelXferClock is connected to each of the 8 segments on the printhead, so that on a single pulse, all segments transfer their bits at the same time.

The NozzleSelect, BankEnable and ColorEnable lines are connected to each of the 8 segments, allowing the printhead interface to independently control the duration of the cyan, magenta, and yellow nozzle energizing pulses. Registers in the Print Head Interface allow the accurate specification of the pulse duration between 0 and 6 ms, with a typical duration of 2 ms to 3 ms.

A parallel interface 125 connects the ICP to individual static electrical signals. The CPU is able to control each of these connections as memory mapped I/O via a low speed bus.

The following is a table of connections to the parallel interface:

	Connection	Direction	Pins
	Paper transport stepper motor	Output	4
	Capping solenoid	Output	1
	Copy LED	Output	1
	Photo button	Input	1
	Copy button	Input	1
	Total		8

A serial interface is also included to allow authentication of the refill station. This is included to ensure that the cameras are only refilled with paper and ink at authorized refill stations, thus preventing inferior quality refill industry from occurring. The camera must authenticate the refill station, rather than the other way around. The secure protocol is communicated to the refill station via a serial data connection. Contact can be made to four gold plated spots on the ICP/printhead TAB by the refill station as the new ink is injected into the printhead.

Seven high current drive transistors e.g. 227 are required. Four are for the four phases of the main stepper motor two are for the guillotine motor, and the remaining transistor is to drive the capping solenoid. These transistors are allocated 20,000 square microns (600,000 F) each. As the transistors are driving highly inductive loads, they must either be turned off slowly, or be provided with a high level of back EMF protection. If adequate back EMF protection cannot be provided using the chip process chosen, then external discrete transistors should be used. The transistors are never driven at the same time as the image sensor is used. This is to avoid voltage fluctuations and hot spots affecting the image quality. Further, the transistors are located as far away from the sensor as possible.

A standard JTAG (Joint Test Action Group) interface 228 is included in the ICP for testing purposes and for interrogation by the refill station. Due to the complexity of the chip, a variety of testing techniques are required, including BIST (Built In Self Test) and functional block isolation. An overhead of 10% in chip area is assumed for chip testing circuitry for the random logic portions. The overhead for the large arrays (the image sensor and the DRAM) is smaller.

The JTAG interface is also used for authentication of the refill station. This is included to ensure that the cameras are only refilled with quality paper and ink at a properly constructed refill station, thus preventing inferior quality refills from occurring. The camera must authenticate the refill station, rather than vice versa. The secure protocol is communicated to the refill station during the automated test procedure. Contact is made to four gold plated spots on the ICP/printhead TAB by the refill station as the new ink is injected into the printhead.

FIG. 16 illustrates rear view of the next step in the construction process whilst FIG. 17 illustrates a front camera view.

Turning now to FIG. 16 , the assembly of the camera system proceeds via first assembling the ink supply mechanism 40 . The flex PCB is interconnected with batteries only one of which is shown at 84 , which are inserted in the middle portion of a print roll 85 which is wrapped around a plastic former 86 . An end cap 89 is provided at the other end of the print roll 85 so as to fasten the print roll and batteries firmly to the ink supply mechanism.

The solenoid coil is interconnected (not shown) to interconnects 97 , 98 ( FIG. 8 ) which include leaf spring ends for interconnection with electrical contacts on the Flex PCB so as to provide for electrical control of the solenoid.

Turning now to FIGS. 17-19 the next step in the construction process is the insertion of the relevant gear chains into the side of the camera chassis. FIG. 17 illustrates a front camera view, FIG. 18 illustrates a back side view and FIG. 19 also illustrates a back side view. The first gear chain comprising gear wheels 22 , 23 are utilized for driving the guillotine blade with the gear wheel 23 engaging the gear wheel 65 of FIG. 8 . The second gear chain comprising gear wheels 24 , 25 and 26 engage one end of the print roller 61 of FIG. 8 . As best indicated in FIG. 18 , the gear wheels mate with corresponding buttons on the surface of the chassis with the gear wheel 26 being snap fitted into corresponding mating hole 27 .

Next, as illustrated in FIG. 20 , the assembled platen unit is then inserted between the print roll 85 and aluminum cutting blade 43 .

Turning now to FIG. 21 , by way of illumination, there is illustrated the electrically interactive components of the camera system. As noted previously, the components are based around a Flex PCB board and include a TAB film 58 which interconnects the printhead 102 with the image sensor and processing chip 51 . Power is supplied by two AA type batteries 83 , 84 and a paper drive stepper motor 16 is provided in addition to a rotary guillotine motor 17 .

An optical element 31 is provided for snapping into a top portion of the chassis 12 . The optical element 31 includes portions defining an optical view finder 32 , 33 which are slotted into mating portions 35 , 36 in view finder channel 37 . Also provided in the optical element 31 is a lensing system 38 for magnification of the prints left number in addition to an optical pipe element 39 for piping light from the LED 5 for external display.

Turning next to FIG. 22 , the assembled unit 90 is then inserted into a front outer case 91 which includes button 4 for activation of printouts.

Turning now to FIG. 23 , next, the unit 92 is provided with a snap-on back cover 93 which includes a slot 6 and copy print button 7 . A wrapper label containing instructions and advertising (not shown) is then wrapped around the outer surface of the camera system and pinch clamped to the cover by means of clamp strip 96 which can comprise a flexible plastic or rubber strip.

Subsequently, the preferred embodiment is ready for use as a one time use camera system that provides for instant output images on demand.

It will be evident that the preferred embodiment further provides for a refillable camera system. A used camera can be collected and its outer plastic cases removed and recycled. A new paper roll and batteries can be added and the ink cartridge refilled. A series of automatic test routines can then be carried out to ensure that the printer is properly operational. Further, in order to ensure only authorised refills are conducted so as to enhance quality, routines in the on-chip program ROM can be executed such that the camera authenticates the refilling station using a secure protocol. Upon authentication, the camera can reset an internal paper count and an external case can be fitted on the camera system with a new outer label. Subsequent packing and shipping can then take place.

It will be further readily evident to those skilled in the art that the program ROM can be modified so as to allow for a variety of digital processing routines. In addition to the digitally enhanced photographs optimized for mainstream consumer preferences, various other models can readily be provided through mere re-programming of the program ROM. For example, a sepia classic old fashion style output can be provided through a remapping of the color mapping function. A further alternative is to provide for black and white outputs again through a suitable color remapping algorithm. Minimumless color can also be provided to add a touch of color to black and white prints to produce the effect that was traditionally used to colorize black and white photos. Further, passport photo output can be provided through suitable address remappings within the address generators. Further, edge filters can be utilized as is known in the field of image processing to produce sketched art styles. Further, classic wedding borders and designs can be placed around an output image in addition to the provision of relevant clip arts. For example, a wedding style camera might be provided. Further, a panoramic mode can be provided so as to output the well known panoramic format of images. Further, a postcard style output can be provided through the printing of postcards including postage on the back of a print roll surface. Further, clip arts can be provided for special events such as Halloween, Christmas etc. Further, kaleidoscopic effects can be provided through address remappings and wild color effects can be provided through remapping of the color lookup table. Many other forms of special event cameras can be provided for example, cameras dedicated to the Olympics, movie tie-ins, advertising and other special events.

The operational mode of the camera can be programmed so that upon the depressing of the take photo a first image is sampled by the sensor array to determine irrelevant parameters. Next a second image is again captured which is utilised for the output. The captured image is then manipulated in accordance with any special requirements before being initially output on the paper roll. The LED light is then activated for a predetermined time during which the DRAM is refreshed so as to retain the image. If the print copy button is depressed during this predetermined time interval, a further copy of the photo is output. After the predetermined time interval where no use of the camera has occurred, the onboard CPU shuts down all power to the camera system until such time as the take button is again activated. In this way, substantial power savings can be realized.

Ink Jet Technologies

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.

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.

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.

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:

low power (less than 10 Watts)

high resolution capability (1,600 dpi or more)

photographic quality output

low manufacturing cost

small size (pagewidth times minimum cross section)

high speed (<2 seconds per page).

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 list under the heading Cross References to Related Applications.

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

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 covered in U.S. patent application Ser. No. 09/112,764, 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.

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.

Tables of Drop-on-Demand Ink Jets

The present invention is useful in the field of digital printing, in particular, ink jet printing. A number of patent applications in this field were filed simultaneously and incorporated by cross reference.

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.

The following tables form the axes of an eleven dimensional table of ink jet types.

Actuator mechanism (18 types)

Basic operation mode (7 types)

Auxiliary mechanism (8 types)

Actuator amplification or modification method (17 types)

Actuator motion (19 types)

Nozzle refill method (4 types)

Method of restricting back-flow through inlet (10 types)

Nozzle clearing method (9 types)

Nozzle plate construction (9 types)

Drop ejection direction (5 types)

Ink type (7 types)

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. Forty-five such inkjet types were filed simultaneously to the present application.

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 forty-five examples can be made into ink jet print heads with characteristics superior to any currently available ink jet technology.

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 simultaneously filed patent applications by the present applicant are listed by USSN numbers. In some cases, a print technology may be listed more than once in a table, where it shares characteristics with more than one entry.

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.

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

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Thermal	An electrothermal	Large force	High power	Canon Bubblejet 1979
bubble	heater heats the ink	generated	Ink carrier limited	Endo et al GB patent
	to above boiling	Simple	to water	2,007,162
	point, transferring	construction	Low efficiency	Xerox heater-in-pit
	significant heat to	No moving	High temperatures	1990 Hawkins et al
	the aqueous ink. A	parts	required	U.S. Pat. No. 4,899,181
	bubble nucleates	Fast operation	High mechanical	Hewlett-Packard TIJ
	and quickly forms,	Small chip area	stress	1982 Vaught et al
	expelling the ink.	required for	Unusual materials	U.S. Pat. No. 4,490,728
	The efficiency of the	actuator	required
	process is low, with		Large drive
	typically less than		transistors
	0.05% of the		Cavitation causes
	electrical energy		actuator failure
	being transformed		Kogation reduces
	into kinetic energy		bubble formation
	of the drop.		Large print heads
			are difficult to
			fabricate
Piezo-	A piezoelectric	Low power	Very large area	Kyser et al U.S.
electric	crystal such as lead	consumption	required for	Pat. No. 3,946,398
	lanthanum zirconate	Many ink types	actuator	Zoltan U.S. Pat. No.
	(PZT) is electrically	can be used	Difficult to	3,683,212
	activated, and either	Fast operation	integrate with	1973 Stemme U.S.
	expands, shears, or	High efficiency	electronics	Pat. No. 3,747,120
	bends to apply		High voltage drive	Epson Stylus
	pressure to the ink,		transistors	Tektronix
	ejecting drops.		required	U.S. Ser. No. 09/112,803
			Full pagewidth
			print heads
			impractical due to
			actuator size
			Requires electrical
			poling in high
			field strengths
			during
			manufacture

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Electro-	An electric field is	Low power	Low maximum	Seiko Epson, Usui et all
strictive	used to activate	consumption	strain (approx.	JP 253401/96
	electrostriction in	Many ink types	0.01%)	U.S. Ser. No. 09/112,803
	relaxor materials	can be used	Large area
	such as lead	Low thermal	required for
	lanthanum zirconate	expansion	actuator due to
	titanate (PLZT) or	Electric field	low strain
	lead magnesium	strength	Response speed is
	niobate (PMN).	required	marginal (˜10 μs)
		(approx. 3.5	High voltage drive
		V/μm) can be	transistors
		generated	required
		without	Full pagewidth
		difficultly	print heads
		Does not	impractical due to
		require	actuator size
		electrical poling
Ferro-	An electric field is	Low power	Difficult to	U.S. Ser. No. 09/112,803
electric	used to induce a	consumption	integrate with
	phase transition	Many ink types	electronics
	between the	can be used	Unusual materials
	antiferroelectric	Fast operation	such as PLZSnT
	(AFE) and	(<1 μs)	are required
	ferroelectric (FE)	Relatively high	Actuators require
	phase. Perovskite	longitudinal	a large area
	materials such as tin	strain
	modified lead	High efficiency
	lanthanum zirconate	Electric field
	titanate (PLZSnT)	strength of
	exhibit large strains	around 3 V/μm
	of up to 1%	can be readily
	associated with the	provided
	AFE to FE phase
	transition.

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Electro-	Conductive plates	Low power	Difficult to	U.S. Ser. No. 09/112,787;
static	are separated by a	consumption	operate	09/112,803
plates	compressible or	Many ink types	electrostatic
	fluid dielectric	can be used	devices in an
	(usually air). Upon	Fast operation	aqueous
	application of a		environment
	voltage, the plates		The electrostatic
	attract each other		actuator will
	and displace ink,		normally need to
	causing drop		be separated from
	ejection. The		the ink
	conductive plates		Very large area
	may be in a comb or		required to
	honeycomb		achieve high
	structure, or stacked		forces
	to increase the		High voltage drive
	surface area and		transistors may be
	therefore the force.		required
			Full pagewidth
			print heads are not
			competitive due to
			actuator size
Electro-	A strong electric	Low current	High voltage	1989 Saito et al,
static pull	field is applied to	consumption	required	U.S. Pat. No. 4,799,068
on ink	the ink, whereupon	Low	May be damaged	1989 Miura et al,
	electrostatic	temperature	by sparks due to	U.S. Pat. No. 4,810,954
	attraction		air breakdown	Tone-jet
	accelerates the ink		Required field
	towards the print		strength increases
	medium.		as the drop size
			decreases
			High voltage drive
			transistors
			required
			Electrostatic field
			attracts dust

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Permanent	An electromagnet	Low power	Complex	U.S. Ser. No. 09/113,084;
magnet	directly attracts a	consumption	fabrication	09/112,779
electro-	permanent magnet,	Many ink types	Permanent
magnetic	displacing ink and	can be used	magnetic material
	causing drop	Fast operation	such as
	ejection. Rare earth	High efficiency	Neodymium Iron
	magnets with a field	Easy extension	Boron (NdFeB)
	strength around 1	from single	required.
	Tesla can be used.	nozzles to	High local
	Examples are:	pagewidth print	currents required
	Samarium Cobalt	heads	Copper
	(SaCo) and		metalization
	magnetic materials		should be used for
	in the neodymium		long
	iron boron family		electromigration
	(NdFeB,		lifetime and low
	NdDyFeBNb,		resistivity
	NdDyFeB, etc)		Pigmented inks
			are usually
			infeasible
			Operating
			temperature
			limited to the
			Curie temperature
			(around 540 K.)
Soft	A solenoid induced	Low power	Complex	U.S. Ser. No. 09/112,751;
magnetic	a magnetic field in a	consumption	fabrication	09/113,097; 09/113,066;
core	soft magnetic core	Many ink types	Materials not	09/112,779; 09/113,061;
electro-	or yoke fabricated	can be used	usually present in	09/112,816; 09/112,772;
magnetic	from a ferrous	Fast operation	a CMOS fab such	09/112,815
	material such as	High efficiency	as NiFe, CoNiFe,
	electroplated iron	Easy extension	or CoFe are
	alloys such as	from single	required
	CoNiFe [1], CoFe,	nozzles to	High local
	or NiFe alloys.	pagewidth print	currents required
	Typically, the soft	heads	Copper
	magnetic material is		metalization
	in two parts, which		should be used for
	are normally held		long
	apart by a spring.		electromigration
	When the solenoid		lifetime and low
	is actuated, the two		resistivity
	parts attract,		Electroplating is
	displacing the ink.		required
			High saturation
			flux density is
			required (2.0-2.1
			T is achievable
			with CoNiFe [1])

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Lorenz	The Lorenz force	Low power	Force acts as a	U.S. Ser. No. 09/113,099;
force	acting on a current	consumption	twisting motion	09/113,077; 09/112,818;
	carrying wire in a	Many ink types	Typically, only a	09/112,819
	magnetic field is	can be used	quarter of the
	utilized.	Fast operation	solenoid length
	This allows the	High efficiency	provides force in a
	magnetic field to be	Easy extension	useful direction
	supplied externally	from single	High local
	to the print head,	nozzles to	currents required
	for example	pagewidth print	Copper
	with rare earth	heads	metalization
	permanent magnets.		should be used for
	Only the current		long
	carrying wire need		electromigration
	be fabricated on the		lifetime and low
	print-head,		resistivity
	simplifying		Pigmented inks
	materials		are usually
	requirements.		infeasible
Magneto-	The actuator uses	Many ink types	Force acts as a	Fischenbeck, U.S.
striction	the giant	can be used	twisting motion	Pat. No. 4,032,929
	magnetostrictive	Fast operation	Unusual materials	U.S. Ser. No. 09/113,121
	effect of materials	Easy extension	such as Terfenol-
	such as Terfenol-D	from single	D are required
	(an alloy of terbium,	nozzles to	High local
	dysprosium and iron	pagewidth print	currents required
	developed at the	heads	Copper
	Naval Ordnance	High force is	metalization
	Laboratory, hence	available	should be used for
	Ter-Fe-NOL). For		long
	best efficiency, the		electromigration
	actuator should be		lifetime and low
	pre-stressed to		resistivity
	approx. 8 MPa.		Pre-stressing may
			be required
Surface	Ink under positive	Low power	Requires	Silverbrook, EP 0771
tension	pressure is held in a	consumption	supplementary	658 A2 and related
reduction	nozzle by surface	Simple	force to effect	patent applications
	tension. The surface	construction	drop separation
	tension of the ink is	No unusual	Requires special
	reduced below the	materials	ink surfactants
	bubble threshold,	required in	Speed may be
	causing the ink to	fabrication	limited by
	egress from the	High efficiency	surfactant
	nozzle.	Easy extension	properties
		from single
		nozzles to
		pagewidth print
		heads

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Viscosity	The ink viscosity is	Simple	Requires	Silverbrook, EP 0771
reduction	locally reduced to	construction	supplementary	658 A2 and related
	select which drops	No unusual	force to effect	patent applications
	are to be ejected. A	materials	drop separation
	viscosity reduction	required in	Requires special
	can be achieved	fabrication	ink viscosity
	electrothermally	Easy extension	properties
	with most inks, but	from single	High speed is
	special inks can be	nozzles to	difficult to achieve
	engineered for a	pagewidth print	Requires
	100:1 viscosity	heads	oscillating ink
	reduction.		pressure
			A high
			temperature
			difference
			(typically 80
			degrees) is
			required
Acoustic	An acoustic wave is	Can operate	Complex drive	1993 Hadimioglu et al,
	generated and	without a nozzle	circuitry	EUP 550,192
	focussed upon the	plate	Complex	1993 Elrod et al, EUP
	drop ejection region.		fabrication	572,220
			Low efficiency
			Poor control of
			drop position
			Poor control of
			drop volume
Thermo-	An actuator which	Low power	Efficient aqueous	U.S. Ser. No. 09/112,802;
elastic	relies upon	consumption	operation requires	09/112,778; 09/112,815;
bend	differential thermal	Many ink types	a thermal insulator	09/113,096; 09/113,068;
actuator	expansion upon	can be used	on the hot side	09/113,095; 09/112,808;
	Joule heating is	Simple planar	Corrosion	09/112,809; 09/112,780;
	used.	fabrication	prevention can be	09/113,083; 09/112,793;
		Small chip area	difficult	09/112,794; 09/113,128;
		required for	Pigmented inks	09/113,127; 09/112,756;
		each actuator	may be infeasible,	09/112,755; 09/112,754;
		Fast operation	as pigment	09/112,811; 09/112,812;
		High efficiency	particles may jam	09/112,813; 09/112,814;
		CMOS	the bend actuator	09/112,764; 09/112,765;
		compatible		09/112,767; 09/112,768
		voltages and
		currents
		Standard
		MEMS
		processes can
		be used
		Easy extension
		from single
		nozzles to
		pagewidth print
		heads

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
High CTE	A material with a	High force can	Requires special	U.S. Ser. No. 09/112,778;
thermo-	very high coefficient	be generated	material (e.g.	09/112,815; 09/113,096;
elastic	of thermal	Three methods	PTFE)	09/113,095; 09/112,808;
actuator	expansion (CTE)	of PTFE	Requires a PTFE	09/112,809; 09/112,780;
	such as	deposition are	deposition	09/113,083; 09/112,793;
	polytetrafluoroethylene	under	process, which is	09/112,794; 09/113,128;
	(PTFE) is used.	development:	not yet standard in	09/113,127; 09/112,756;
	As high CTE	chemical vapor	ULSI fabs	09/112,807; 09/112,806;
	materials are usually	deposition	PTFE deposition	09/112,820
	non-conductive, a	(CVD), spin	cannot be
	heater fabricated	coating, and	followed with
	from a conductive	evaporation	high temperature
	material is	PTFE is a	(above 350° C.)
	incorporated. A 50	candidate for	processing
	μm long PTFE bend	low dielectric	Pigmented inks
	actuator with	constant	may be infeasible,
	polysilicon heater	insulation in	as pigment
	and 15 mW power	ULSI	particles may jam
	Input can provide	Very low power	the bend actuator
	180 μN force and 10	consumption
	μm deflection.	Many ink types
	Actuator motions	can be used
	include:	Simple planar
	Bend	fabrication
	Push	Small chip area
	Buckle	required for
	Rotate	each actuator
		Fast operation
		high efficiency
		CMOS
		compatible
		voltages and
		currents
		Easy extension
		from single
		nozzles to
		pagewidth print
		heads

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Conduct-	A polymer with a	High force can	Requires special	U.S. Ser. No. 09/113,083
ive	high coefficient of	be generated	materials
polymer	thermal expansion	Very low power	development
thermo-	(such as PTFE) is	consumption	(High CTE
elastic	doped with	Many ink types	conductive
actuator	conducting	can be used	polymer)
	substances to	Simple planar	Requires a PTFE
	increase its	fabrication	deposition
	conductivity to	Small chip area	process, which is
	about 3 orders of	required for	not yet standard
	magnitude below	each actuator	in ULSI fabs
	that of copper. The	Fast operation	PTFE deposition
	conducting polymer	High efficiency	cannot be
	expands when	CMOS	followed with
	resistively heated.	compatible	high temperature
	Examples of	voltages and	(above 350° C.)
	conducting dopants	currents	processing
	include:	Easy extension	Evaporation and
	Carbon nanotubes	from single	CVD deposition
	Metal fibers	nozzles to	techniques cannot
	Conductive	pagewidth print	be used
	polymers such as	heads	Pigmented inks
	doped		may be infeasible,
	polythiophene		as pigment
	Carbon granules		particles may jam
			the bend actuator
Shape	A shape memory	High force is	Fatigue limits	U.S. Ser. No. 09/113,122
memory	alloy such as TiNi	available	maximum number
alloy	(also known as	(stresses of	of cycles
	Nitinol - Nickel	hundreds of	Low strain (1%) is
	Titanium alloy	MPa)	required to extend
	developed at the	Large strain is	fatigue resistance
	Naval Ordnance	available (more	Cycle rate limited
	Laboratory) is	than 3%)	by heat removal
	thermally switched	High corrosion	Requires unusual
	between its weak	resistance	materials (TiNi)
	martensitic state and	Simple	The latent heat of
	its high stiffness	construction	transformation
	austenic state. The	Easy extension	must be provided
	shape of the actuator	from single	High current
	in its martensitic	nozzles to	operation
	state is deformed	pagewidth print	Requires pre-
	relative to the	heads	stressing to distort
	austenic shape. The	Low voltage	the martensitic
	shape change causes	operation	state
	ejection of a drop.

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Linear	Linear magnetic	Linear Magnetic	Requires unusual	U.S. Ser. No. 09/113,061
Magnetic	actuators include the	actuators can be	semiconductor
Actuator	Linear Induction	constructed with	materials such as
	Actuator (LIA),	high thrust, long	soft magnetic
	Linear Permanent	travel, and high	alloys (e.g.
	Magnet	efficiency using	CoNiFe)
	Synchronous	planar	Some varieties
	Actuator (LPMSA),	semiconductor	also require
	Linear Reluctance	fabrication	permanent
	Synchronous	techniques	magnetic
	Actuator (LRSA),	Long actuator	materials such as
	Linear Switched	travel is	Neodymium iron
	Reluctance Actuator	available	boron (NdFeB)
	(LSRA), and the	Medium force is	Requires complex
	Linear Stepper	available	multi-phase drive
	Actuator (LSA).	Low voltage	circuitry
		operation	High current
			operation

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)
	Description	Advantages	Disadvantages	Examples
Linear	Linear magnetic	Linear Magnetic	Requires unusual	U.S. Ser. No. 09/113,061
Magnetic	actuators include the	actuators can be	semiconductor
Actuator	Linear Induction	constructed with	materials such as
	Actuator (LIA),	high thrust, long	soft magnetic
	Linear Permanent	travel, and high	alloys (e.g.
	Magnet	efficiency using	CoNiFe)
	Synchronous	planar	Some varieties
	Actuator (LPMSA),	semiconductor	also require
	Linear Reluctance	fabrication	permanent
	Synchronous	techniques	magnetic
	Actuator (LRSA),	Long actuator	materials such as
	Linear Switched	travel is	Neodymium iron
	Reluctance Actuator	available	boron (NdFeB)
	(LSRA), and the	Medium force is	Requires complex
	Linear Stepper	available	multi-phase drive
	Actuator (LSA).	Low voltage	circuitry
		operation	High current
			operation

BASIC OPERATION MODE
	Description	Advantages	Disadvantages	Examples
Proximity	The drops to be	Very simple	Requires close	Silverbrook, EP 0771
	printed are selected	print head	proximity	658 A2 and related
	by some manner	fabrication can	between the print	patent applications
	(e.g. thermally	be used	head and the
	induced surface	The drop	print media or
	tension reduction of	selection means	transfer roller
	pressurized ink).	does not need to	May require two
	Selected drops are	provide the	print heads
	separated from the	energy required	printing alternate
	ink in the nozzle by	to separate the	rows of the
	contact with the	drop from the	image
	print medium or a	nozzle	Monolithic color
	transfer roller.		print heads are
			difficult
Electro-	The drops to be	Very simple	Requires very	Silverbrook, EP 0771
static pull	printed are selected	print head	high electrostatic	658 A2 and related
on ink	by some manner	fabrication can	field	patent applications
	(e.g. thermally	be used	Electrostatic field	Tone-Jet
	induced surface	The drop	for small nozzle
	tension reduction of	selection means	sizes is above air
	pressurized ink).	does not need to	breakdown
	Selected drops are	provide the	Electrostatic field
	separated from the	energy required	may attract dust
	ink in the nozzle by	to separate the
	a strong electric	drop from the
	field.	nozzle
Magnetic	The drops to be	Very simple	Requires	Silverbrook, EP 0771
pull on ink	printed are selected	print head	magnetic ink	658 A2 and related
	by some manner	fabrication can	Ink colors other	patent applications
	(e.g. thermally	be used	than black are
	induced surface	The drop	difficult
	tension reduction of	selection means	Requires very
	pressurized ink).	does not need to	high magnetic
	Selected drops are	provide the	fields
	separated from the	energy required
	ink in the nozzle by	to separate the
	a strong magnetic	drop from the
	field acting on the	nozzle
	magnetic ink.
Shutter	The actuator moves	High speed	Moving parts are	U.S. Ser. No. 09/112,818;
	a shutter to block	(>50 kHz)	required	09/112,815; 09/112,808
	ink flow to the	operation can be	Requires ink
	nozzle. The ink	achieved due to	pressure
	pressure is pulsed at	reduced refill	modulator
	a multiple of the	time	Friction and wear
	drop ejection	Drop timing can	must be
	frequency.	be very accurate	considered
		The actuator	Stiction is
		energy can be	possible
		very low

BASIC OPERATION MODE
	Description	Advantages	Disadvantages	Examples
Shuttered	The actuator moves	Actuators with	Moving parts are	U.S. Ser. No. 09/113,066;
grill	a shutter to block	small travel can	required	09/112,772; 09/113,096;
	ink flow through a	be used	Requires ink	09/113,068
	grill to the nozzle.	Actuators with	pressure
	The shutter	small force can	modulator
	movement need	be used	Friction and wear
	only be equal to the	High speed	must be
	width of the grill	(>50 kHz)	considered
	holes.	operation can be	Stiction is
		achieved	possible
Pulsed	A pulsed magnetic	Extremely low	Requires an	U.S. Ser. No. 09/112,779
magnetic	field attracts an ‘ink	energy	external pulsed
pull on ink	pusher’ at the drop	operation is	magnetic field
pusher	ejection frequency.	possible	Requires special
	An actuator controls	No heat	materials for both
	a catch, which	dissipation	the actuator and
	prevents the ink	problems	the ink pusher
	pusher from moving		Complex
	when a drop is not		construction
	to be ejected.

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)
	Description	Advantages	Disadvantages	Examples
None	The actuator directly	Simplicity of	Drop ejection	Most ink jets, including
	fires the ink drop,	construction	energy must be	piezoelectric and thermal
	and there is no	Simplicity of	supplied by	bubble.
	external field or	operation	individual nozzle	U.S. Ser. No. 09/112,751;
	other mechanism	Small physical	actuator	09/112,787; 09/112,802;
	required.	size		09/112,803; 09/113,097;
				09/113,084; 09/113,078;
				09/113,077; 09/113,061;
				09/112,816; 09/113,095;
				09/112,809; 09/112,780;
				09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820
Oscillating	The ink pressure	Oscillating ink	Requires external	Silverbrook, EP 0771
ink	oscillates, providing	pressure can	ink pressure	658 A2 and related
pressure	much of the drop	provide a refill	oscillator	patent applications
(including	ejection energy. The	pulse, allowing	Ink pressure	U.S. Ser. No. 09/113,066;
acoustic	actuator selects	higher operating	phase and	09/112,818; 09/112,772;
stimulation)	which drops are to	speed	amplitude must	09/112,815; 09/113,096;
	be fired by	The actuators	be carefully	09/113,068; 09/112,808;
	selectively blocking	may operate	controlled
	or enabling nozzles.	with much	Acoustic
	The ink pressure	lower energy	reflections in the
	oscillation may be	Acoustic lenses	ink chamber
	achieved by	can be used to	must be designed
	vibrating the print	focus the sound	for
	head, or preferably	on the nozzles
	by an actuator in the
	ink supply.
Media	The print head is	Low power	Precision	Silverbrook, EP 0771
proximity	placed in close	High accuracy	assembly	658 A2 and related
	proximity to the	Simple print	required	patent applications
	print medium.	head	Paper fibers may
	Selected drops	construction	cause problems
	protrude from the		Cannot print on
	print head further		rough substrates
	than unselected
	drops, and contact
	the print medium.
	The drop soaks into
	the medium fast
	enough to cause
	drop separation.

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)
	Description	Advantages	Disadvantages	Examples
Transfer	Drops are printed to	High accuracy	Bulky	Silverbrook, EP 0771
roller	a transfer roller	Wide range of	Expensive	658 A2 and related
	instead of straight to	print substrates	Complex	patent applications
	the print medium. A	can be used	construction	Tektronix hot melt
	transfer roller can	Ink can be dried		piezoelectric ink jet
	also be used for	on the transfer		Any of U.S. Ser. No.
	proximity drop	roller		09/112,751; 09/112,787;
	separation.			09/112,802; 09/112,803;
				09/113,097; 09/113,099;
				09/113,084; 09/113,066;
				09/112,778; 09/112,779;
				09/113,077; 09/113,061;
				09/112,818; 09/112,816;
				09/112,772; 09/112,819;
				09/112,815; 09/113,096;
				09/113,068; 09/113,095;
				09/112,808; 09/112,809;
				09/112,780; 09/113,083;
				09/113,121; 09/113,122;
				09/112,793; 09/112,794;
				09/113,128; 09/113,127;
				09/112,756; 09/112,755;
				09/112,754; 09/112,811;
				09/112,812; 09/112,813;
				09/112,814; 09/112,764;
				09/112,765; 09/112,767;
				09/112,768; 09/112,807;
				09/112,806; 09/112,820;
				09/112,821
Electro-	An electric field is	Low power	Field strength	Silverbrook, EP 0771
static	used to accelerate	Simple print	required for	658 A2 and related
	selected drops	head	separation of	patent applications
	towards the print	construction	small drops is	Tone-Jet
	medium.		near or above air
			breakdown
Direct	A magnetic field is	Low power	Requires	Silverbrook, EP 0771
magnetic	used to accelerate	Simple print	magnetic ink	658 A2 and related
field	selected drops of	head	Requires strong	patent applications
	magnetic ink	construction	magnetic field
	towards the print
	medium.
Cross	The print head is	Does not	Requires external	U.S. Ser. No. 09/113,099;
magnetic	placed in a constant	require	magnet	09/112,819
field	magnetic field. The	magnetic	Current densities
	Lorenz force in a	materials to be	may be high,
	current carrying	integrated in the	resulting in
	wire is used to move	print head	electromigration
	the actuator.	manufacturing	problems
		process

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)
	Description	Advantages	Disadvantages	Examples
Pulsed	A pulsed magnetic	Very low power	Complex print	U.S. Ser. No. 09/112,779
magnetic	field is used to	operation is	head construction
field	cyclically attract a	possible	Magnetic
	paddle, which	Small print head	materials
	pushes on the ink. A	size	required in print
	small actuator		head
	moves a catch,
	which selectively
	prevents the paddle
	from moving.

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)
	Description	Advantages	Disadvantages	Examples
Pulsed	A pulsed magnetic	Very low power	Complex print	U.S. Ser. No. 09/112,779
magnetic	field is used to	operation is	head construction
field	cyclically attract a	possible	Magnetic
	paddle, which	Small print head	materials
	pushes on the ink. A	size	required in print
	small actuator		head
	moves a catch,
	which selectively
	prevents the paddle
	from moving.

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD
	Description	Advantages	Disadvantages	Examples
Reverse	The actuator loads a	Better coupling	Fabrication	U.S. Ser. No. 09/113,097;
spring	spring. When the	to the ink	complexity	09/113,077
	actuator is turned		High stress in
	off, the spring		the 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 travel	Increased	Some piezoelectric ink
stack	actuators are	Reduced drive	fabrication	jets
	stacked. This can be	voltage	complexity	U.S. Ser. No. 09/112,803
	appropriate where		Increased
	actuators require		possibility of
	high electric field		short circuits
	strength, such as		due to pinholes
	electrostatic and
	piezoelectric
	actuators.
Multiple	Multiple smaller	Increases the	Actuator forces	U.S. Ser. No. 09/113,061;
actuators	actuators are used	force available	may not add	09/112,818; 09/113,096;
	simultaneously to	from an actuator	linearly,	09/113,095; 09/112,809;
	move the ink. Each	Multiple	reducing	09/112,794; 09/112,807;
	actuator need	actuators can be	efficiency	09/112,806
	provide only a	positioned to
	portion of the force	control ink flow
	required.	accurately
Linear	A linear spring is	Matches low	Requires print	U.S. Ser. No. 09/112,772
Spring	used to transform a	travel actuator	head area for
	motion with small	with higher	the spring
	travel and high force	travel
	into a longer travel,	requirements
	lower force motion.	Non-contact
		method of
		motion
		transformation
Coiled	A bend actuator is	Increases travel	Generally	U.S. Ser. No. 09/112,815;
actuator	coiled to provide	Reduces chip	restricted to	09/112,808; 09/112,811;
	greater travel in a	area	planar	09/112,812
	reduced chip area.	Planar	implementations
		implementations	due to extreme
		are relatively	fabrication
		easy to	difficulty in
		fabricate.	other
			orientations.

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD
	Description	Advantages	Disadvantages	Examples
Flexure	A bend actuator has	Simple means	Care must be	U.S. Ser. No. 09/112,779;
bend	a small region near	of increasing	taken not to	09/113,068; 09/112,754
actuator	the fixture point,	travel of a bend	exceed the
	which flexes much	actuator	elastic limit in
	more readily than		the flexure area
	the remainder of the		Stress
	actuator. The		distribution is
	actuator flexing is		very uneven
	effectively		Difficult to
	converted from an		accurately
	even coiling to an		model with
	angular bend,		finite element
	resulting in greater		analysis
	travel of the actuator
	tip.
Catch	The actuator	Very low	Complex	U.S. Ser. No. 09/112,779
	controls a small	actuator energy	construction
	catch. The catch	Very small	Requires
	either enables or	actuator size	external force
	disables movement		Unsuitable for
	of an ink pusher that		pigmented inks
	is controlled in a
	bulk manner.
Gears	Gears can be used to	Low force, low	Moving parts	U.S. Ser. No. 09/112,818
	increase travel at the	travel actuators	are required
	expense of duration.	can be used	Several actuator
	Circular gears, rack	Can be	cycles are
	and pinion, ratchets,	fabricated using	required
	and other gearing	standard surface	More complex
	methods can be	MEMS	drive electronics
	used.	processes	Complex
			construction
			Friction,
			friction, and
			wear are
			possible
Buckle	A buckle plate can	Very fast	Must stay	S. Hirata et al, “An Ink-jet
plate	be used to change a	movement	within elastic	Head Using Diaphragm
	slow actuator into a	achievable	limits of the	Microactuator”, Proc.
	fast motion. It can		materials for	IBEE MEMS, Feb. 1996,
	also convert a high		long device life	pp 418-423.
	force, low travel		High stresses	U.S. Ser. No. 09/113,096;
	actuator into a high		involved	09/112,793
	travel, medium		Generally high
	force motion.		power
			requirement
Tapered	A tapered magnetic	Linearizes the	Complex	U.S. Ser. No. 091/112,816
magnetic	pole can increase	magnetic	construction
pole	travel at the expense	force/distance
	of force.	curve

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD
	Description	Advantages	Disadvantages	Examples
Lever	A lever and fulcrum	Matches low	High stress	U.S. Ser. No. 09/112,755;
	is used to transform	travel actuator	around the	09/112,813; 09/112,814
	a motion with small	with higher	fulcrum
	travel and high force	travel
	into a motion with	requirements
	longer travel and	Fulcrum area
	lower force. The	has no linear
	lever can also	movement, and
	reverse the direction	can be used for
	of travel.	a fluid seal
Rotary	The actuator is	High	Complex	U.S. Ser. No. 09/112,794
impeller	connected to a	mechanical	construction
	rotary impeller. A	advantage	Unsuitable for
	small angular	The ratio of	pigmented inks
	deflection of the	force to travel
	actuator results in a	of the actuator
	rotation of the	can be matched
	impeller vanes,	to the nozzle
	which push the ink	requirements by
	against stationary	varying the
	vanes and out of the	number of
	nozzle.	impeller vanes
Acoustic	A refractive or	No moving	Large area	1993 Hadimioglu et al,
lens	diffractive (e.g.	parts	required	EUP 550,192
	zone plate) acoustic		Only relevant	1993 Elrod et al, EUP
	lens is used to		for acoustic ink	572,220
	concentrate sound		jets
	waves.
Sharp	A sharp point is	Simple	Difficult to	Tone-jet
conductive	used to concentrate	construction	fabricate using
point	an electrostatic		standard VLSI
	field.		processes for a
			surface ejecting
			ink-jet
			Only relevant
			for electrostatic
			ink jets

ACTUATOR MOTION
	Description	Advantages	Disadvantages	Examples
Volume	The volume of the	Simple	High energy is	Hewlett-Packard Thermal
expansion	actuator changes,	construction in	typically	Ink jet
	pushing the ink in	the case of	required to	Canon Bubblejet
	all directions.	thermal ink jet	achieve volume
			expansion. This
			leads to thermal
			stress,
			cavitation, and
			kogation in
			thermal ink jet
			implementations
Linear,	The actuator moves	Efficient	High fabrication	U.S. Ser. No. 09/112,751;
normal to	in a direction normal	coupling to ink	complexity may	09/112,787; 09/112,803;
chip	to the print head	drops ejected	be required to	09/113,084; 09/113,077;
surface	surface. The nozzle	normal to the	achieve	09/112,816
	is typically in the	surface	perpendicular
	line of movement.		motion
Parallel to	The actuator moves	Suitable for	Fabrication	U.S. Ser. No. 09/113,061;
chip	parallel to the print	planar	complexity	09/112,818; 09/112,772;
surface	head surface. Drop	fabrication	Friction	09/112,754; 09/112,811;
	ejection may still be		Stiction	09/112,812; 09/112,813
	normal to the
	surface.
Membrane	An actuator with a	The effective	Fabrication	1982 Howkins U.S.
push	high force but small	area of the	complexity	Pat. No. 4,459,601
	area is used to push	actuator	Actuator size
	a stiff membrane	becomes the	Difficulty of
	that is in contact	membrane area	integration in a
	with the ink.		VLSI process
Rotary	The actuator causes	Rotary levers	Device	U.S. Ser. No. 09/113,097;
	the rotation of some	may be used to	complexity	09/113,066; 09/112,818;
	element, such a grill	increase travel	May have	09/112,794
	or impeller	Small chip area	friction at a
		requirements	pivot point
Bend	The actuator bends	A very small	Requires the	1970 Kyser et al U.S.
	when energized.	change in	actuator to be	Pat. No. 3,946,398
	This may be due to	dimensions can	made from at	1973 Stemme U.S. Pat. No.
	differential thermal	be converted to	least two	3,747,120
	expansion,	a large motion.	distinct layers,	09/112,802; 09/112,778;
	piezoelectric		or to have a	09/112,779; 09/113,068;
	expansion,		thermal	09/112,780; 09/113,083;
	magnetostriction, or		difference	09/113,121; 09/113,128;
	other form of		across the	09/113,127; 09/112,756;
	relative dimensional		actuator	09/112,754; 09/112,811;
	change.			09/112,812

ACTUATOR MOTION
	Description	Advantages	Disadvantages	Examples
Swivel	The actuator swivels	Allows	Inefficient	U.S. Ser. No. 09/113,099
	around a central	operation where	coupling to the
	pivot. This motion is	the net linear	ink motion
	suitable where there	force on the
	are opposite forces	paddle is zero
	applied to opposite	Small chip area
	sides of the paddle,	requirements
	e.g. Lorenz force.
Straighten	The actuator is	Can be used	Requires careful	U.S. Ser. No. 09/113,122;
	normally bent, and	with shape	balance of	09//112,755
	straightens when	memory alloys	stresses to
	energized.	where the	ensure that the
		austenic phase	quiescent bend
		is planar	is accurate
Double	The actuator bends	One actuator	Difficult to	U.S. Ser. No. 09/112,813;
bend	in one direction	can be used to	make the drops	09/112,814; 09/112,764
	when one element is	power two	ejected by both
	energized, and	nozzles.	bend directions
	bends the other way	Reduced chip	identical.
	when another	size.	A small
	element is	Not sensitive to	efficiency loss
	energized.	ambient	compared to
		temperature	equivalent
			single bend
			actuators.
Shear	Energizing the	Can increase the	Not readily	1985 Fishbeck U.S.
	actuator causes a	effective travel	applicable to	Pat. No. 4,584,590
	shear motion in the	of piezoelectric	other actuator
	actuator material.	actuators	mechanisms
Radial	The actuator	Relatively easy	High force	1970 Zoftan U.S. Pat. No.
constriction	squeezes an ink	to fabricate	required	3,683,212
	reservoir, forcing	single nozzles	Inefficient
	ink from a	from glass	Difficult to
	constricted nozzle.	tubing as	integrate with
		macroscopic	VLSI processes
		structures
Coil/	A coiled actuator	Easy to	Difficult to	U.S. Ser. No. 09/112,815;
uncoil	uncoils or coils	fabricate as a	fabricate for	091/112,808; 09/112,811;
	more tightly. The	planar VLSI	non-planar	09/112,812
	motion of the free	process	devices
	end of the actuator	Small area	Poor out-of-
	ejects the ink.	required,	plane stiffness
		therefore low
		cost
Bow	The actuator bows	Can increase the	Maximum	U.S. Ser. No. 09/112,819;
	(or buckles) in the	speed of travel	travel is	09/113,096; 09/112,793
	middle when	Mechanically	constrained
	energized.	rigid	High force
			required

ACTUATOR MOTION
	Description	Advantages	Disadvantages	Examples
Push-Pull	Two actuators	The structure is	Not readily	U.S. Ser. No. 09/113,096
	control a shutter.	pinned at both	suitable for ink
	One actuator pulls	ends, so has a	jets which
	the shutter, and the	high out-of-	directly push
	other pushes it.	plane rigidity	the ink
Curl	A set of actuators	Good fluid flow	Design	U.S. Ser. No. 09/113,095;
inwards	curl inwards to	to the region	complexity	09/112,807
	reduce the volume	behind the
	of ink that they	actuator
	enclose.	increases
		efficiency
Curl	A set of actuators	Relatively	Relatively large	U.S. Ser. No. 09/112,806
outwards	curl outwards,	simple	chip area
	pressurizing ink in a	construction
	chamber
	surrounding the
	actuators, and
	expelling ink from a
	nozzle in the
	chamber.
Iris	Multiple vanes	High efficiency	High fabrication	U.S. Ser. No. 09/112,809
	enclose a volume of	Small chip area	complexity
	ink. These		Not suitable for
	simultaneously		pigmented inks
	rotate, reducing the
	volume between the
	vanes.
Acoustic	The actuator	The actuator	Large area	1993 Hadimioglu et al,
vibration	vibrates at a high	can be	required for	EUP 550,192
	frequency.	physically	efficient	1993 Elrod et at, EUP
		distant from the	operation at	572,220
		ink	useful
			frequencies
			Acoustic
			coupling and
			crosstalk
			Complex drive
			circuitry
			Poor control of
			drop volume
			and position
None	In various ink jet	No moving	Various other	Silverbrook, EP 0771 658
	designs the actuator	parts	tradeoffs are	A2 and related patent
	does not move.		required to	applications
			eliminate	Tone-jet
			moving parts

NOZZLE REFILL METHOD
	Description	Advantages	Disadvantages	Examples
Surface	This is the normal	Fabrication	Low speed	Thermal ink jet
tension	way that ink jets are	simplicity	Surface tension	Piezoelectric ink jet
	refilled. After the	Operational	force relatively	U.S. Ser. No. - 09/112,751;
	actuator is energized,	simplicity	small	09/113,084; 09/112,779;
	it typically returns		compared to	09/112,816; 09/112,819;
	rapidly to its normal		actuator force	09/113,095; 09/112,809;
	position. This rapid		Long refill	09/112,780; 09/113,083;
	return sucks in air		time usually	09/113,121; 09/113,122;
	through the nozzle		dominates the	09/112,793; 09/112,794;
	opening. The ink		total repetition	09/113,128; 09/113,127;
	surface tension at the		rate	09/112,756; 09/112,755;
	nozzle then exerts a			09/112,754; 09/112,811;
	small force restoring			09/112,812; 09/112,813;
	the meniscus to a			09/112,814; 09/112,764;
	minimum area. This			09/112,765; 09/112,767;
	force refills the			09/112,768; 09/112,807;
	nozzle.			09/112,806; 09/112,820;
				09/112,821
Shuttered	Ink to the nozzle	High speed	Requires	U.S. Ser. No. 09/113,066;
oscillating	chamber is provided	Low actuator	common ink	09/112,818; 09/112,772;
ink	at a pressure that	energy, as the	pressure	09/112,815; 09/113,096;
pressure	oscillates at twice the	actuator need	oscillator	09/113,068; 09/112,808
	drop ejection	only open or	May not be
	frequency. When a	close the	suitable for
	drop is to be ejected,	shutter, instead	pigmented inks
	the shutter is opened	of ejecting the
	for 3 half cycles:	ink drop
	drop ejection,
	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, as	Requires two	U.S. Ser. No. 09/112,778
actuator	actuator has ejected a	the nozzle is	independent
	drop a second (refill)	actively	actuators per
	actuator is energized.	refilled	nozzle
	The refill actuator
	pushes ink into the
	nozzle chamber. The
	refill actuator returns
	slowly, to prevent its
	return from emptying
	the chamber again.

NOZZLE REFILL METHOD
	Description	Advantages	Disadvantages	Examples
Positive	The ink is held a	High refill rate,	Surface spill	Silverbrook, EP 0771 658
ink	slight positive	therefore a	must be	A2 and related patent
pressure	pressure. After the	high drop	prevented	applications
	ink drop is ejected,	repetition rate	Highly	Alternative for: U.S. Ser. No.
	the nozzle chamber	is possible	hydrophobic	09/112,751; 09/112,787;
	fills quickly as		print head	09/112,802; 09/112,803;
	surface tension and		surfaces are	09/113,097; 09/113,099;
	ink pressure both		required	09/113,084; 09/112,779;
	operate to refill the			09/113,077; 09/113,061;
	nozzle.			09/112,818; 09/112,816;
				09/112,819; 09/113,095;
				09/112,809; 09/112,780;
				09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128,
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET
	Description	Advantages	Disadvantages	Examples
Long inlet	The ink inlet	Design	Restricts refill	Thermal ink jet
channel	channel to the	simplicity	rate	Piezoelectric ink jet
	nozzle chamber is	Operational	May result in a	U.S. Ser. No. 09/112,807;
	made long and	simplicity	relatively large	09/112,806
	relatively narrow,	Reduces	chip area
	relying on viscous	crosstalk	Only partially
	drag to reduce inlet		effective
	back-flow.
Positive	The ink is under a	Drop selection	Requires a	Silverbrook, EP 0771 658
ink	positive pressure, so	and separation	method (such	A2 and related patent
pressure	that in the quiescent	forces can be	as a nozzle rim	applications
	state some of the ink	reduced	or effective	Possible operation of the
	drop already	Fast refill time	hydrophobizing,	following:
	protrudes from the		or both) to	U.S. Ser. No. 09/112,751;
	nozzle.		prevent	09/112,787; 09/112,802;
	This reduces the		flooding of the	09/112,803; 09/113,097;
	pressure in the		ejection	09/113,099; 09/113,084;
	nozzle chamber		surface of the	09/112,778; 09/112,779;
	which is required to		print head.	09/113,077; 09/113,061;
	eject a certain			09/112,816; 09/112,819;
	volume of ink. The			09/113,095; 09/112,809;
	reduction in			09/112,780; 09/113,083;
	chamber pressure			09/113,121; 09/113,122;
	results in a			09/112,793; 09/112,794;
	reduction in ink			09/113,128; 09/113,127;
	pushed out through			09/112,756; 09/112,755;
	the inlet.			09/112,754; 09/112,811;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
Baffle	One or more baffles	The refill rate is	Design	HP Thermal Ink Jet
	are placed in the	not as restricted	complexity	Tektronix piezoelectric ink
	inlet ink flow. When	as the long inlet	May increase	jet
	the actuator is	method.	fabrication
	energized, the rapid	Reduces	complexity
	ink movement	crosstalk	(e.g. Tektronix
	creates eddies which		hot melt
	restrict the flow		Piezoelectric
	through the inlet.		print heads).
	The slower refill
	process is
	unrestricted, and
	does not result in
	eddies.

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET
	Description	Advantages	Disadvantages	Examples
Flexible	In this method	Significantly	Not applicable	Canon
flap	recently disclosed	reduces back-	to most ink jet
restricts	by Canon, the	flow for edge-	configurations
inlet	expanding actuator	shooter thermal	Increased
	(bubble) pushes on a	ink jet devices	fabrication
	flexible flap that		complexity
	restricts the inlet.		Inelastic
			deformation of
			polymer flap
			results in creep
			over extended
			use
Inlet filter	A filter is located	Additional	Restricts refill	U.S. Ser. No. 09/112,803;
	between the ink	advantage of	rate	09/113,061; 09/113,083;
	inlet and the nozzle	ink filtration	May result in	09/112,793; 09/113,128;
	chamber. The filter	Ink filter may	complex	09/113,127
	has a multitude of	be fabricated	construction
	small holes or slots,	with no
	restricting ink flow.	additional
	The filter also	process steps
	removes particles
	which may block
	the nozzle.
Small inlet	The ink inlet	Design	Restricts refill	U.S. Ser. No. 09/112,787;
compared	channel to the	simplicity	rate	09/112,814; 09/112,820
to nozzle	nozzle chamber has		May result in a
	a substantially		relatively large
	smaller cross section		chip area
	than that of the		Only partially
	nozzle, resulting in		effective
	easier ink egress out
	of the nozzle than
	out of the inlet.
Inlet	A secondary	Increases speed	Requires	U.S. Ser. No. 09/112,778
shutter	actuator controls the	of the ink-jet	separate refill
	position of a shutter,	print head	actuator and
	closing off the ink	operation	drive circuit
	inlet when the main
	actuator is
	energized.
The inlet	The method avoids	Back-flow	Requires	U.S. Ser. No. 09/112,751;
is located	the problem of inlet	problem is	careful design	09/112,802; 09/113,097;
behind the	back-flow by	eliminated	to minimize	09/113,099; 09/113,084;
ink-	arranging the ink-		the negative	09/112,779; 09/113,077;
pushing	pushing surface of		pressure	09/112,816; 09/112,819;
surface	the actuator between		behind the	09/112,809; 09/112,780;
	the inlet and the		paddle	09/113,121; 09/112,794;
	nozzle.			09/112,756; 09/112,755;
				09/112,754; 09/112,811;
				09/112,812; 09/112,813;
				09/112,765; 09/112,767;
				09/112,768

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET
	Description	Advantages	Disadvantages	Examples
Part of the	The actuator and a	Significant	Small increase	U.S. Ser. No. 09/113,084;
actuator	wall of the ink	reductions in	in fabrication	09/113,095; 09/113,122;
moves to	chamber are	back-flow can	complexity	09/112,764
shut off	arranged so that the	be achieved
the inlet	motion of the	Compact
	actuator closes off	designs possible
	the inlet.
Nozzle	In some	Ink back-flow	None related to	Silverbrook, EP 0771 658
actuator	configurations of	problem is	ink back-flow	A2 and related patent
does not	ink jet, there is no	eliminated	on actuation	applications
result in	expansion or			Valve-jet
ink back-	movement of an			Tone-jet
flow	actuator which may
	cause ink back-flow
	through the inlet.

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET
	Description	Advantages	Disadvantages	Examples
Part of the	The actuator and a	Significant	Small increase	U.S. Ser. No. 09/113,084;
actuator	wall of the ink	reductions in	in fabrication	09/113,095; 09/113,122;
moves to	chamber are	back-flow can	complexity	09/112,764
shut off	arranged so that the	be achieved
the inlet	motion of the	Compact
	actuator closes off	designs possible
	the inlet.
Nozzle	In some	Ink back-flow	None related to	Silverbrook, EP 0771 658
actuator	configurations of	problem is	ink back-flow	A2 and related patent
does not	ink jet, there is no	eliminated	on actuation	applications
result in	expansion or			Valve-jet
ink back-	movement of an			Tone-jet
flow	actuator which may
	cause ink back-flow
	through the inlet.

NOZZLE CLEARING METHOD
	Description	Advantages	Disadvantages	Examples
Rapid	The actuator is fired	Does not	Effectiveness	May be used with: U.S. Ser. No.
succession	in rapid succession.	require extra	depends	09/112,751; 09/112,787;
of actuator	In some	drive circuits on	substantially	09/112,802; 09/112,803;
pulses	configurations, this	the print head	upon the	09/113,097; 09/113,099;
	may cause heat	Can be readily	configuration	09/113,084; 09/112,778;
	build-up at the	controlled and	of the ink jet	09/112,779; 09/113,077;
	nozzle which boils	initiated by	nozzle	09/112,816; 09/112,819;
	the ink, clearing the	digital logic		09/113,095; 09/112,809;
	nozzle. In other			09/112,780; 09/113,083;
	situations, it may			09/113,121; 09/112,793;
	cause sufficient			09/112,794; 09/113,128;
	vibrations to			09/113,127; 09/112,756;
	dislodge clogged			09/112,755; 09/112,754;
	nozzles.			09/112,811; 09/112,813;
				09/112,814; 09/112,764;
				09/112,765; 09/112,767;
				09/112,768; 09/112,807;
				09/112,806; 09/112,820;
				09/112,821
Extra	Where an actuator is	A simple	Not suitable	May be used with: U.S. Ser. No.
power to	not normally driven	solution where	where there is	09/112,802; 09/112,778;
ink	to the limit of its	applicable	a hard limit to	09/112,819; 09/113,095;
pushing	motion, nozzle		actuator	09/112,780; 09/113,083;
actuator	clearing may be		movement	09/113,121; 09/112,793;
	assisted by			09/113,128; 09/113,127;
	providing an			09/112,756; 09/112,755;
	enhanced drive			09/112,765; 09/112,767;
	signal to the			09/112,768; 09/112,807;
	actuator.			09/112,806; 09/112,820;
				09/112,821
Acoustic	An ultrasonic wave	A high nozzle	High	U.S. Ser. No. 09/113,066;
resonance	is applied to the ink	clearing	implementation	09/112,818; 09/112,772;
	chamber. This wave	capability can	cost if	09/112,815; 09/113,096;
	is of an appropriate	be achieved	system does	09/113,068; 09/112,808
	amplitude and	May be	not already
	frequency to cause	implemented at	include an
	sufficient force at	very low cost in	acoustic
	the nozzle to clear	systems which	actuator
	blockages. This is	already include
	easiest to achieve if	acoustic
	the ultrasonic wave	actuators
	is at a resonant
	frequency of the ink
	cavity.

NOZZLE CLEARING METHOD
	Description	Advantages	Disadvantages	Examples
Nozzle	A microfabricated	Can clear	Accurate	Silverbrook, EP 0771 658
clearing	plate is pushed	severely	mechanical	A2 and related patent
plate	against the nozzles.	clogged nozzles	alignment is	applications
	The plate has a post		required
	for every nozzle. A		Moving parts
	post moves through		are required
	each nozzle,		There is risk of
	displacing dried ink.		damage to the
			nozzles
			Accurate
			fabrication is
			required
Ink	The pressure of the	May be	Requires	May be used with ink jets
pressure	ink is temporarily	effective where	pressure pump	covered by U.S. Ser. No.
pulse	increased so that ink	other methods	or other	09/112,751; 09/112,787;
	streams from all of	cannot be used	pressure	09/112,802; 09/112,803;
	the nozzles. This		actuator	09/113,097; 09/113,099;
	may be used in		Expensive	09/113,084; 09/113,066;
	conjunction with		Wasteful of	09/112,778; 09/112,779;
	actuator energizing.		ink	09/113,077; 09/113,061;
				09/112,818; 09/112,816;
				09/112,772; 09/112,819;
				09/112,815; 09/113,096;
				09/113,068; 09/113,095;
				09/112,808; 09/112,809;
				09/112,780; 09/113,083;
				09/113,121; 09/113,122;
				09/112,793; 09/112,794;
				09/113,128; 09/113,127;
				09/112,756; 09/112,755;
				09/112,754; 09/112,811;
				09/112,812; 09/112,813;
				09/112,814; 09/112,764;
				09/112,765; 09/112,767;
				09/112,768; 09/112,807;
				09/112,806; 09/112,820;
				09/112,821
Print head	A flexible ‘blade’ is	Effective for	Difficult to use	Many ink jet systems
wiper	wiped across the	planar print	if print head
	print head surface.	head surfaces	surface is non-
	The blade is usually	Low cost	planar or very
	fabricated from a		fragile
	flexible polymer,		Requires
	e.g. rubber or		mechanical
	synthetic elastomer.		parts
			Blade can wear
			out in high
			volume print
			systems

NOZZLE CLEARING METHOD
	Description	Advantages	Disadvantages	Examples
Separate	A separate heater is	Can be effective	Fabrication	Can be used with many ink
ink boiling	provided at the	where other	complexity	jets covered by U.S. Ser. No.
heater	nozzle although the	nozzle clearing		09/112,751; 09/112,787;
	normal drop e-	methods cannot		09/112,802; 09/112,803;
	ection mechanism	be used		09/113,097; 09/113,099;
	does not require it.	Can be		09/113,084; 09/113,066;
	The heaters do not	implemented at		09/112,778; 09/112,779;
	require individual	no additional		09/113,077; 09/113,061;
	drive circuits, as	cost in some ink		09/112,818; 09/112,816;
	many nozzles can be	jet		09/112,772; 09/112,819;
	cleared	configurations		09/112,815; 09/113,096;
	simultaneously, and			09/113,068; 09/113,095;
	no imaging is			09/112,808; 09/112,809;
	required.			09/112,780; 09/113,083;
				09/113,121; 09/113,122;
				09/112,793; 09/112,794;
				09/113,128; 09/113,127;
				09/112,756; 09/112,755;
				09/112,754; 09/112,811;
				09/112,812; 09/112,813;
				09/112,814; 09/112,764;
				09/112,765; 09/112,767;
				09/112,768; 09/112,807;
				09/112,806; 09/112,820;
				09/112,821

NOZZLE PLATE CONSTRUCTION
	Description	Advantages	Disadvantages	Examples
Electro-	A nozzle plate is	Fabrication	High	Hewlett Packard Thermal
formed	separately fabricated	simplicity	temperatures	Ink jet
nickel	from electroformed		and pressures
	nickel, and bonded		are required to
	to the print head		bond nozzle
	chip.		plate
			Minimum
			thickness
			constraints
			Differential
			thermal
			expansion
Laser	Individual nozzle	No masks	Each hole must	Canon Bubblejet
ablated or	holes are ablated by	required	be individually	1988 Sercel et al., SPIE,
drilled	an intense UV laser	Can be quite	formed	Vol. 998 Excimer Beam
polymer	in a nozzle plate,	fast	Special	Applications, pp. 76-83
	which is typically a	Some control	equipment	1993 Watanabe et at.,
	polymer such as	over nozzle	required	U.S. Pat. No. 5,208,604
	polyimide or	profile is	Slow where
	polysulphone	possible	there are many
		Equipment	thousands of
		required is	nozzles per
		relatively low	print head
		cost	May produce
			thin burrs at
			exit holes
Silicon	A separate nozzle	High accuracy	Two part	K. Bean, IBEE
micro-	plate is	is attainable	construction	Transactions on Electron
machined	micromachined		High cost	Devices, Vol. ED-25, No.
	from single crystal		Requires	10, 1978, pp 1185-1195
	silicon, and bonded		precision	Xerox 1990 Hawkins et at.,
	to the print head		alignment	U.S. Pat. No. 4,899,181
	wafer.		Nozzles may
			be clogged by
			adhesive
Glass	Fine glass	No expensive	Very small	1970 Zoltan U.S. Pat. No.
capillaries	capillaries are drawn	equipment	nozzle sizes	3,683,212
	from glass tubing.	required	are difficult to
	This method has	Simple to make	form
	been used for	single nozzles	Not suited for
	making individual		mass
	nozzles, but is		production
	difficult to use for
	bulk manufacturing
	of print heads with
	thousands of
	nozzles.

NOZZLE PLATE CONSTRUCTION
	Description	Advantages	Disadvantages	Examples
Monolithic,	The nozzle plate is	High accuracy	Requires	Silverbrook, EP 0771 658
surface	deposited as a layer	(<1 μm)	sacrificial layer	A2 and related patent
micro-	using standard VLSI	Monolithic	under the	applications
machined	deposition	Low cost	nozzle plate to	U.S. Ser. No. 09/112,751;
using VLSI	techniques. Nozzles	Existing	form the	09/112,787; 09/112,803;
litho-	are etched in the	processes can	nozzle	09/113,077; 09/113,061;
graphic	nozzle plate using	be used	chamber	09/112,815; 09/113,096;
processes	VLSI lithography		Surface may	09/113,095; 09/112,809;
	and etching.		be fragile to	09/113,083; 09/112,793;
			the touch	09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,813;
				09/112,814; 09/112,764;
				09/112,765; 09/112,767;
				09/112,768; 09/112,807;
				09/112,806; 09/112,820
Monolithic,	The nozzle plate is a	High accuracy	Requires long	U.S. Ser. No. 09/112,802;
etched	buried etch stop in	(<1 μm)	etch times	09/113,097; 09/113,099;
through	the wafer. Nozzle	Monolithic	Requires a	09/113,084; 09/113,066;
substrate	chambers are etched	Low cost	support wafer	09/112,778; 09/112,779;
	in the front of the	No differential		09/112,818; 09/112,816;
	wafer, and the wafer	expansion		09/112,772; 09/112,819;
	is thinned from the			09/113,068; 09/112,808;
	back side. Nozzles			09/112,780; 09/113,121;
	are then etched in			09/113,122
	the etch stop layer.
No nozzle	Various methods	No nozzles to	Difficult to	Ricoh 1995 Sekiya et al
plate	have been tried to	become clogged	control drop	U.S. Pat. No. 5,412,413
	eliminate the		position	1993 Hadimioglu et at EUP
	nozzles entirely, to		accurately	550,192
	prevent nozzle		Crosstalk	1993 Elrod et at EUP
	clogging. These		problems	572,220
	include thermal
	bubble mechanisms
	and acoustic lens
	mechanisms
Trough	Each drop ejector	Reduced	Drop firing	U.S. Ser. No. 09/112,812
	has a trough through	manufacturing	direction is
	which a paddle	complexity	sensitive to
	moves. There is no	Monolithic	wicking.
	nozzle plate.
Nozzle slit	The elimination of	No nozzles to	Difficult to	1989 Saito et al
instead of	nozzle holes and	become clogged	control drop	U.S. Pat. No. 4,799,068
individual	replacement by a slit		position
nozzles	encompassing many		accurately
	actuator positions		Crosstalk
	reduces nozzle		problems
	clogging, but
	increases crosstalk
	due to ink surface
	waves

DROP EJECTION DIRECTION
	Description	Advantages	Disadvantages	Examples
Edge	Ink flow is along the	Simple	Nozzles	Canon Bubblejet 1979
(‘edge	surface of the chip,	construction	limited to edge	Endo et al GB patent
shooter’)	and ink drops are	No silicon	High	2,007,162
	ejected from the	etching required	resolution is	Xerox heater-in-pit 1990
	chip edge.	Good heat	difficult	Hawkins et al U.S.
		sinking via	Fast color	Pat. No. 4,899,181
		substrate	printing	Tone-jet
		Mechanically	requires one
		strong	print head per
		Ease of chip	color
		handing
Surface	Ink flow is along the	No bulk silicon	Maximum ink	Hewlett-Packard TIJ 1982
(‘roof	surface of the chip,	etching required	flow is	Vaught et at U.S. Pat. No.
shooter’)	and ink drops are	Silicon can	severely	4,490,728
	ejected from the	make an	restricted	U.S. Ser. No. 09/112,787,
	chip surface, normal	effective heat		09/113,077; 09/113,061;
	to the plane of the	sink		09/113,095; 09/112,809
	chip.	Mechanical
		strength
Through	Ink flow is through	High ink flow	Requires bulk	Silverbrook, EP 0771 658
chip,	the chip, and ink	Suitable for	silicon etching	A2 and related patent
forward	drops are ejected	pagewidth print		applications
(‘up	from the front	heads		U.S. Ser. No. 09/112,803;
shooter’)	surface of the chip.	High nozzle		09/112,815; 09/113,096;
		packing density		09/113,083; 09/112,793;
		therefore low		09/112,794; 09/113,128;
		manufacturing		09/113,127; 09/112,756;
		cost		09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821
Through	Ink flow is through	High ink flow	Requires wafer	U.S. Ser. No. 09/112,751;
chip,	the chip, and ink	Suitable for	thinning	09/112,802; 09/113,097;
reverse	drops are ejected	pagewidth print	Requires	09/113,099; 09/113,084;
(‘down	from the rear	heads	special	09/113,066; 09/112,778;
shooter’)	surface of the chip.	High nozzle	handling	09/112,779; 09/112,818;
		packing density	during	09/112,816; 09/112,772;
		therefore low	manufacture	09/112,819;
		manufacturing		09/113,068; 09/112,808;
		cost		09/112,780; 09/113,121;
				09/113,122

DROP EJECTION DIRECTION
	Description	Advantages	Disadvantages	Examples
Through	Ink flow is through	Suitable for	Pagewidth	Epson Stylus
actuator	the actuator, which	piezoelectric	print heads	Tektronix hot melt
	is not fabricated as	print heads	require several	piezoelectric ink jets
	part of the same		thousand
	substrate as the		connections to
	drive transistors.		drive circuits
			Cannot be
			manufactured
			in standard
			CMOS fabs
			Complex
			assembly
			required

INK TYPE
	Description	Advantages	Disadvantages	Examples
Aqueous,	Water based ink	Environmentally	Slow drying	Most existing ink jets
dye	which typically	friendly	Corrosive	U.S. Ser. No. 09/112,751;
	contains: water, dye,	No odor	Bleeds on	09/112,787; 09/112,802;
	surfactant,		paper	09/112,803; 09/113,097;
	humectant, and		May	09/113,099; 09/113,084;
	biocide.		strikethrough	09/113,066; 09/112,778;
	Modern ink dyes		Cockles paper	09/112,779; 09/113,077;
	have high water-			09/113,061; 09/112,818;
	fastness, light			09/112,816; 09/112,772;
	fastness			09/112,819; 09/112,815;
				09/113,096; 09/113,068;
				09/113,095; 09/112,808;
				09/112,809; 09/112,780;
				09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821
				Silverbrook, EP 0771 658
				A2 and related patent
				applications
Aqueous,	Water based ink	Environmentally	Slow drying	U.S. Ser. No. 09/112,787;
pigment	which typically	friendly	Corrosive	09/112,803; 09/112,808;
	contains: water,	No odor	Pigment may	09/113,122; 09/112,793;
	pigment, surfactant,	Reduced bleed	clog nozzles	09/113,127
	humectant, and	Reduced	Pigment may	Silverbrook, EP 0771 658
	biocide.	wicking	clog actuator	A2 and related patent
	Pigments have an	Reduced	mechanisms	applications
	advantage in	strikethrough	Cockles paper	Piezoelectric ink-jets
	reduced bleed,			Thermal ink jets (with
	wicking and			significant restrictions)
	strikethrough.

INK TYPE
	Description	Advantages	Disadvantages	Examples
Methyl	MEK is a highly	Very fast	Odorous	U.S. Ser. No. 09/112,751;
Ethyl	volatile solvent used	drying	Flammable	09/112,787; 09/112,802;
Ketone	for industrial	Prints on		09/112,803; 09/113,097;
(MEK)	printing on	various		09/113,099; 09/113,084;
	difficult surfaces	substrates such		09/113,066; 09/112,778;
	such as	as metals and		09/112,779; 09/113,077;
	aluminum cans.	plastics		09/113,061; 09/112,818;
				09/112,816; 09/112,772;
				09/112,819; 09/112,815;
				09/113,096; 09/113,068;
				09/113,095; 09/112,808;
				09/112,809; 09/112,780;
				09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821
Alcohol	Alcohol based inks	Fast drying	Slight odor	U.S. Ser. No. 09/112,751;
(ethanol,	can be used where	Operates at	Flammable	09/112,787; 09/112,802;
2-butanol,	the printer must	sub-freezing		09/112,803; 09/113,097;
and	operate at	temperatures		09/113,099; 09/113,084;
others)	temperatures below	Reduced paper		09/113,066; 09/112,778;
	the freezing point of	cockle		09/112,779; 09/113,077;
	water. An example	Low cost		09/113,061; 09/112,818;
	of this is in-camera			09/112,816; 09/112,772;
	consumer			09/112,819; 09/112,815;
	photographic			09/113,096; 09/113,068;
	printing.			09/113,095; 09/112,808;
				09/112,809; 09/112,780;
				09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821

INK TYPE
	Description	Advantages	Disadvantages	Examples
Phase	The ink is solid at	No drying	High viscosity	Tektronix hot melt
change	room temperature, and	time - ink	Printed ink	piezoelectric ink jets
(hot melt)	is melted in the print	instantly	typically has a	1989 Nowak U.S. Pat. No.
	head before jetting.	freezes on the	‘waxy’ feel	4,820,346
	Hot melt inks are	print medium	Printed pages	U.S. Ser. No. 09/112,751;
	usually wax based,	Almost any	may ‘block’	09/112,787; 09/112,802;
	with a melting	print medium	Ink	09/112,803; 09/113,097;
	point around 80° C.	can be used	temperature	09/113,099; 09/113,084;
	After jetting the ink	No paper	may be above	09/113,066; 09/112,778;
	freezes almost	cockle occurs	the curie point	09/112,779; 09/113,077;
	instantly upon	No wicking	of permanent	09/113,061; 09/112,818;
	contacting the print	occurs	magnets	09/112,816; 09/112,772;
	medium or a	No bleed	Ink heaters	09/112,819; 09/112,815;
	transfer roller.	occurs	consume	09/113,096; 09/113,068;
		No	power	09/113,095; 09/112,808;
		strikethrough	Long warm-up	09/112,809; 09/112,780;
		occurs	time	09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821
Oil	Oil based inks are	High solubility	High viscosity:	U.S. Ser. No. 09/112,751;
	extensively used in	medium for	this is a	09/112,787; 09/112,802;
	offset printing. They	some dyes	significant	09/112,803; 09/113,097;
	have advantages in	Does not	limitation for	09/113,099; 09/113,084;
	improved	cockle paper	use in ink jets,	09/113,066; 09/112,778;
	characteristics on	Does not wick	which usually	09/112,779; 09/113,077;
	paper (especially no	through paper	require a low	09/113,061; 09/112,818;
	wicking or cockle).		viscosity.	09/112,816; 09/112,772;
	Oil soluble dies and		Some short	09/112,819; 09/112,815;
	pigments are		chain and	09/113,096; 09/113,068;
	required.		multi-branched	09/113,095; 09/112,808;
			oils have a	09/112,809; 09/112,780;
			sufficiently	09/113,083; 09/113,121;
			low viscosity.	09/113,122; 09/112,793;
			Slow drying	09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821

INK TYPE
	Description	Advantages	Disadvantages	Examples
Micro-	A microemulsion is	Stops ink bleed	Viscosity	U.S. Ser. No. 09/112,751;
emulsion	a stable, self	High dye	higher than	09/112,787; 09/112,802;
	forming emulsion of	solubility	water	09/112,803; 09/113,097;
	oil, water, and	Water, oil, and	Cost is slightly	09/113,099; 09/113,084;
	surfactant. The	amphiphilic	higher than	09/113,066; 09/112,778;
	characteristic drop	soluble dies	water based	09/112,779; 09/113,077;
	size is less than	can be used	ink	09/113,061; 09/112,818;
	100 nm, and is	Can stabilize	High surfactant	09/112,816; 09/112,772;
	determined by the	pigment	concentration	09/112,819; 09/112,815;
	preferred curvature	suspensions	required	09/113,096; 09/113,068;
	of the surfactant.		(around 5%)	09/113,095; 09/112,808;
				09/112,809; 09/112,780;
				09/113,083; 09/113,121;
				09/113,122; 09/112,793;
				09/112,794; 09/113,128;
				09/113,127; 09/112,756;
				09/112,755; 09/112,754;
				09/112,811; 09/112,812;
				09/112,813; 09/112,814;
				09/112,764; 09/112,765;
				09/112,767; 09/112,768;
				09/112,807; 09/112,806;
				09/112,820; 09/112,821

Claims

1. A recyclable, print on demand, digital camera comprising:an image sensor device for sensing an image; a processing means for processing an image sensed by the image sensor device; a supply of print media on to which an image processed by the processing means is printed; a printhead for printing said sensed image on the print media; an indicating means for indicating an image count; and a separating means for separating a part of the print media on to which an image has been printed from a remainder of the supply of print media, the separating means acting on the indicating means for changing said image count as part of the operation of separating each said part from the remainder of the supply of print media.

2. The camera of claim 1 in which the printhead is a pagewidth printhead which has a length corresponding to one of a length and width of an image to be printed.

3. The camera of claim 2 in which the supply of print media moves past the printhead in a direction substantially normal to a longitudinal axis of the printhead, the separating means being displaceable in a direction parallel to said longitudinal axis for separating said part of the supply of print media from the remainder of the supply of print media.

4. The camera of claim 3 in which the separating means includes an engaging formation which engages a complementary formation of the indicating means to change the indication of usage displayed by the indicating means as the separating means moves along its path of travel, the engaging formation and the complementary formation being such that the separating means causes a change in the indication of usage in one direction of traversal of said path of travel of the separating means but does not cause a change in said indication of usage in an opposite direction of traversal of said path of travel.

5. The camera of claim 4 in which the separating means causes a change in the indication of usage as the separating means returns to its rest position after completion of a separating operation.

6. The camera of claim 1 in which the supply of print media is replenishable, the supply of print media being arranged on a chassis with a removable print media path defining means displaceably arranged relative to the chassis.

7. The camera of claim 6 in which the indicating means is arranged on the chassis and the separating means is carried on the print media path defining means.

8. A recyclable, print on demand, digital camera comprising:an image sensor device for sensing an image; a processing means for processing an image sensed by the image sensor device; a supply of print media on to which an image processed by the processing means is printed; a printhead for printing said sensed image on the print media; an indicating means for indicating an image count; a separating means for separating a part of the print media on to which an image has been printed from a remainder of the supply of print media, the separating means acting on the indicating means for changing said image count as part of the operation of separating each said part from the remainder of the supply of print media; the printhead being a pagewidth printhead which has a length corresponding to one of a length and width of an image to be printed; the supply of print media moves past the printhead in a direction substantially normal to a longitudinal axis of the printhead, the separating means being displaceable in a direction parallel to said longitudinal axis for separating said part of the supply of print media from the remainder of the supply of print media; and the separating means includes an engaging formation which engages a complementary formation of the indicating means to change the indication of usage displayed by the indicating means as the separating means moves along its path of travel, the engaging formation and the complementary formation being such that the separating means causes a change in the indication of usage in one direction of traversal of said path of travel of the separating means but does not cause a change in said indication of usage in an opposite direction of traversal of said path of travel.