Abstract: A multi-pass printbar for providing full width printing on a recording medium is provided. The full width printing may be achieved by stepping the printbar in increments corresponding to the combination of the array width of a printhead die and the gap spacing between the printhead dies until full width print coverage on the recording medium occurs. Ink is ejected from an array of orifices on the printbar as the recording medium passes under the printbar. Alternatively, the full width printing may be achieved by fixing the printbar, and its array of orifices, but stepping the document handler, for example a recirculating drum document handler, the recording medium is mounted upon as it passes under the fixed printbar.

Abstract: A multi-pass printbar for providing full width printing on a recording medium is provided. The full width printing may be achieved by stepping the printbar in increments corresponding to the combination of the array width of a printhead die and the gap spacing between the printhead dies until full width print coverage on the recording medium occurs. Ink is ejected from an array of orifices on the printbar as the recording medium passes under the printbar. Alternatively, the full width printing may be achieved by fixing the printbar, and its array of orifices, but stepping the document handler, for example a recirculating drum document handler, the recording medium is mounted upon as it passes under the fixed printbar.

Abstract: The new heater element design has a pit layer which protects the overglaze passivation layer, PSG step region, portions of the Ta layer and dielectric isolation layer and junctions or regions susceptible to the cavitational pressures. Further, the inner walls of the pit layer define the effective heater area and the dopant lines define the actual heater area. In alternative embodiments, the dopant lines define the actual and effective heater areas, and an inner wall and a dopant line define the actual and effective heater areas. Further, when the new heater element designs are incorporated into printheads having full pit channel geometry and open pit channel geometry, the operating lifetime of the printhead is extended because the added protection of the pit layer prevents: 1) passivation damage and cavitational damages of the heater elements; and 2) degradation of heater robustness, hot spot formations and heater failures well into the 109 pulse range.

Abstract: A method for controlling a maintenance unit in a printer includes determining an image type of an image to be printed, the image type being selected from at least a first image type and a second image type different from the first image type, setting a maintenance interval for the maintenance unit in accordance with the image type, wherein a maintenance interval for the first image type is different from a maintenance interval for the second image type. A printer embodying such a method, and in particular a printer for printing an image an a substrate, includes a printhead, a maintenance unit for performing periodic maintenance on the printhead, and a controller for controlling said maintenance unit according to the described method.

Abstract: A thermal ink jet printer including a frame, a printhead mounted to the frame for printing ink images onto a heated and supported substrate, and an efficient substrate heating and supporting assembly mounted to the frame. The efficient substrate heating and supporting assembly includes a heating device, and a substrate supporting member having a front surface including a substrate supporting area for supporting substrates of various sizes one at a time and border areas having a polished finish. The efficient substrate heating and supporting assembly also includes a heat absorbing back surface facing the heating device. The heat absorbing back surface includes an increased heat absorbing area located opposite and centered relative to the substrate supporting area on the front surface.

Abstract: An ink jet printing system is provided with a re-circulating ink system which continuously moves ink through the printhead preventing ink thickening or drying out of the ink at the nozzles during non-print periods. Several printhead embodiments are disclosed in which a continuous ink path is established through the printhead by forming ink channels in various internal portions of the printhead. In one embodiment the ink flows through channels formed in an upper substrate through the non-ejecting nozzle area and exits through channels in which the ink heating resistors are located. In other embodiments the ink enters channels formed in an upper substrate and exits through channels formed in a lower substrate. Ink may be ejected through nozzles formed in a nozzle plate or directly from grooves which form a meniscus at the required ink ejection areas.

Abstract: An ink cartridge for use in a thermal ink jet printer has a printhead with an edgeshooter configuration and improved heat management. The cartridge has a supply of ink in a chamber and a passageway for placing the chamber in fluid communication with the printhead. The printhead has an array of heating elements, one in each of a plurality of ink channels, and located a predetermined distance from the channel opens which serve as nozzles. The passageway directs the ink in a path closely adjacent the heating elements, so that more of the waste heat generated by the heating elements are transferred to the ink prior to entry of the ink into the channels, thereby resulting in more waste heat being carried away by the ejected ink droplets.

Abstract: A method and apparatus for drying liquid ink deposited, in response to image data, on a recording medium moving along a path at a predetermined rate. A recording medium having liquid ink deposited thereon is moved past a dryer in multiple passes to dry areas of high ink coverage. Ink characteristics are optimized for minimum print defects by determining the time between printing and drying. In the case of text only images only one pass through the dryer is required. For areas of high ink coverage, however, multiple passes through the dryer are required and completed either by reciprocation or recirculation at the same predetermined rate.

Abstract: A method of controlling the operation of an ink jet printhead having a burn voltage applied to a transducer nucleating an ink bubble to cause an ink droplet to be ejected from an ink ejecting orifice. The method includes determining a threshold power dissipated by the transducer sufficient to cause the bubble to nucleate, the threshold power being determined by a firing pulse having a pulse length and a threshold voltage, selecting the pulse length of the firing pulse to be approximately equal to a pulse length necessary to achieve the highest effective power dissipation in the transducer, and selecting the burn voltage as a function of the threshold voltage. Changes to the threshold power dissipated by the transducer necessary to eject from the ink ejecting orifice are determined and the pulse length of the firing pulse is adjusted accordingly.

Abstract: An ink jet printer is configured in a hybrid architecture wherein a full width printbar is combined with a partial width color scanning assembly to provide the capability of selectively printing in black only or, alternately, of producing color prints by operating the color scan assembly exclusively. The cost of the hybrid system, when compared to a full width color system using four full width printbars, is greatly reduced. Throughput time is reduced by providing the control circuitry for distinguishing between black only and color operation and selectively controlling the printer mode of operation. The hybrid architecture is particularly useful in a LAN system since it provides a mechanism for balancing the relative color versus black page decomposition speed limitations. Also, the hybrid architecture enables a relatively simple implementation of a checkerboarding technique to suppress banding in output prints.

Abstract: An apparatus for printing a multicolor image on a sheet movable along a sheet path in a process direction. The apparatus includes a first printhead mounted at a first location along the sheet path and containing a first type ink for printing a first portion of the image on the sheet in which the first type ink has a surface tension greater than 40 dynes/cm at room temperature. The apparatus also includes a set of secondary printheads mounted along the sheet path and separated a small gap from the first printhead. The set of secondary printheads each contains a secondary type ink for printing a secondary portion of the multicolor image on the sheet, and each of the secondary type ink has a surface tension less than 40 dynes/cm at room temperature.

Abstract: A thermal ink jet printhead is controlled to minimize missing droplets at elevated operating temperatures by varying the voltage and pulse width applied to the heater element that causes droplets to be formed and ejected. Increasing the applied voltage reduces the size of the formed droplets. At increased operating temperatures, smaller droplets minimize the introduction of air into the nozzles of the printhead upon ejection. Minimizing the introduction of air eliminates printhead misfirings and causes more consistent jetting of the ink droplets.

Abstract: A thermal ink jet printhead has two or more groups of selectively activatable heating elements and associated nozzles with the heating elements and nozzles within each group having the same geometric parameters, but the geometric parameters of the heating elements and nozzles between groups being different, so that the ejection of droplets from the nozzles of different groups have different ink volumes. When continuous tone and grey scale printing is desired various combinations of nozzles from different groups are used to compose a halftone cell, and when high resolution text printing is desired, either the nozzles from one group or the nozzles from both groups in fixed combinations are used to eject ink droplets onto a recording medium.

Abstract: A thermal ink jet printer for printing MICR images by liquid ink droplets. The ink contains a magnetic pigment, magnetic particles, or a combination of both. An external magnetic field in the printing zone orients the magnetic pigment in a preferred direction while the printed ink droplet is still wet, so that the magnetic pigment is mobile in a liquid medium. The printed droplet is allowed to dry under the influence of the magnetic field, thereby permanently preserving the specific orientation. As a result, the remanence of the magnetic material in the images are increased and less magnetic pigment is needed for the necessary signal for MICR. This reduction in magnetic material enables the printing by a thermal ink jet printer, because nozzle clogging is avoidable.

Abstract: A multi-color ink-jet printer in which a first partial image is created on a recording medium, and then a second partial image is created on the same recording medium after the first partial image is substantially dried. The first partial image comprises an ink which dries at a slower rate than that of the second partial image. In one embodiment, means are provided for heating the recording medium prior to the creation of the second partial image.

Abstract: Disclosed is an apparatus for degassing a liquid, comprising: a liquid supply and an outlet communicating with the liquid supply via a flow path; a degassing tank, disposed in the flow path between the liquid supply and the outlet, the degassing tank incorporating a gas-permeable vent; a means for moving the liquid along the flow path; and a heater, disposed in the flow path between the degassing tank and the outlet, for heating the liquid and thereby removing gas therefrom. The apparatus is particularly suited to the ink supply system of a thermal ink jet printer where the removal of gases dissolved in the ink improves print quality.

Abstract: A mechanism for accurately mounting a large area semiconductive device within a larger system is disclosed. The semiconductive device, formed by the linear abutment of semiconductive sub-units divided from a larger semiconductive wafer must be accurately positioned to enable the operation of which it was intended. In one embodiment, the sub-units are thermal ink jet arrays which are abutted to form a pagewidth printhead. The semiconductive device includes a reference plate or substrate having a generally planar surface for mounting an array of functional sub-units thereon. The semiconductive device further includes two or more individual sub-units which are also affixed to the planar surface, thereby forming alignment pads for the assembled semiconductive device. When incorporated into the system, the alignment pads are received by frame members or alignment points to provide positive alignment of the reference plate, and the attached array of sub-units, within the system.

Abstract: Apertureless Direct Electronic Printing (ADEPT) is effected through imagewise toner transfer across a gap by biasing individual electrodes selectively using a localized electrostatic field varying in time in such a way that the approximate impulse relation 1:2 is maintained, between the first, forward directing pulse and the subsequent reverse pulse (or a sequence of alternating pulses). In this improvement, no apertures between the donor and the receiver are utilized, yet imagewise resolution is preserved. In other words undesirable defocusing is preclude. The electrodes, in one embodiment, are implemented as biased discs embedded in a dielectric substrate material.

Abstract: A staggered array printhead, recording medium support and capping and/or maintenance assembly for use in an ink jet printer is described. Capping and maintenance of printhead sub-units of the staggered array is performed by self-positioning and aligning members located on a capping and/or maintenance member which is movably positioned on one side of a recording medium support. The printhead is located on an opposite side of the recording medium support, staggered openings being provided in the support to enable contact between the capping and/or maintenance members and front faces of the printhead subunits. Heat management of the printhead is provided by an ink manifold positioned over the printhead subunits. The manifold includes fingered portions which extend into spaces between the subunits. Assembly of a staggered array printhead is facilitated by the use of a high precision fixture having recesses for the receipt of printhead subunits.

Abstract: Modular partial bars include a substrate bar having a length and a plurality of printhead subunits attached to only one side of the substrate bar, each printhead subunit being spaced from an adjacent printhead subunit. These modular partial bars are used as building blocks to form full width staggered array printheads. When the printhead subunits are arranged on each substrate bar so that two substrate bars are capable of forming a full width staggered array printhead, each modular partial bar is referred to as a modular half bar. One modular half bar can be stacked on another modular half bar any number of ways. For example, two half bars can be stacked with their printhead subunit containing sides facing the same direction, away from one another or towards one another.