Abstract: The nucleation efficiency of a thermal ink jet printhead is improved by forming a heater element with a planar surface. A heater resistor, polysilicon in a preferred embodiment, has an irregular surface which can trap gas or vapors in the cracks or crevices. When the heater resistor is pulsed, the nucleation temperature is reduced by these trapped vapors requiring an increase in electrical input to the resistors, thereby reducing efficiency. The invention recognizes that a heater resistor with a planar surface in contact with an ink layer results in a higher nucleation temperature and increased efficiency. In one embodiment, a phosphosilicate glass (PSG) is flowed directly onto the resistor surface forming a planarization layer. Subsequent deposition of tantalum substantially replicates the underlying topography creating a heater resistor with a smooth surface adjacent the ink.

Abstract: A large array or pagewidth printhead fabricated from printhead elements or subunits. The printhead subunits are butted together at either adjacent channel elements or adjacent heater elements to form a pagewidth printhead. The butting element, either heater or channel element, is slightly wider than the non-butting element thereby providing gaps between the non-butting elements of a printhead element array. Where channel elements are used as the butting element, gaps between the heater elements provide for reduction or elimination of potentially damaging thermal compressive forces between adjacent heater elements. Where heater elements are used as the butting element, structural strength is increased since the heater wafer is stronger than the channel wafer. In addition, the width of the polyimide wall at the edges of the heater wafer is increased providing greater protection for thermal transducers located at the edges of individual heater elements.

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, into producing color prints by operating the color scanning assembly exclusively. The cost of the hybrid system, when compared to a full width color system using four full width printbars, is greatly reduced. The partial width scanning assembly is mounted on a carriage which is stepped along a printing swath width, the sum of the incremental scan steps equaling the width of a full width printbar. A dimensional mismatch between the printbar and the scanning printhead in the direction perpendicular to paper motion (width direction) could result in image degradation because of misalignment of color drops to black drops. The mismatch could result in manufacturing errors in either the printhead width and/or the width of the carriage.

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: A method of fabricating a pagewidth array of buttable printheads reduces end channel damage. The wafer containing a plurality of arrays of channels is provided with V-grooves. A V-groove is positioned between each array. When the wafer is secured to a wafer containing heater plates, wafers are diced along the V-shaped grooves to reduce damage to the end channels of the array to improve print quality.

Abstract: A large array or pagewidth printhead fabricated from printhead elements or subunits having adhesive-free butting edges. Each of the printhead elements includes a heater element and a channel element bonded together by an adhesive such as an epoxy. A space or adhesive-receiving aperture is formed between the channel element and the heater element before mating so that any adhesive forced from between the channel element and heater element by the pressure of mating does not flow onto the butting surfaces, but instead overflows into the space thereby maintaining an adhesive free butting edge. The channel element includes an etch trough which forms the space. The printhead elements are butted together to form a large array printhead. The absence of adhesive on the butting edges improves manufacturability of the large array printhead.

Abstract: An improved ink jet printhead including a channel plate and a heater plate having an improved flatness top bonding surface. The heater plate includes a silicon wafer base, a first insulating layer formed on the wafer base, and at least an intermediate component sublayer formed over the first insulating layer. The heater plate also includes a second insulating layer formed over the at least intermediate component sublayer, and having a top bonding surface for bonding the: heater plate to the channel plate. To substantially improve flatness of the top bonding surface of the second insulating layer, the component sublayer includes active thin film layer patterns in circuit areas of the thin sublayer, and non-active relief compensating patterns in non-circuit areas thereof. The non-active relief-compensating patterns each have a thickness substantially equal to the thickness of the active thin film patterns in the circuit areas of the sublayer.

Abstract: A full width read and/or write assemblies, such as a full width thermal ink jet printbar, is disclosed, having materials with both a high thermal coefficient of expansion and a low thermal coefficient of expansion. A suitable adhesive which provides lateral give while firmly holding the respective components together provides dimensional stability to the printbar element having a low thermal coefficient of expansion when components having high thermal coefficient of expansion are assembled thereto. The flexible or floating mounting enabled by lateral give of the adhesive allows for the application of cost effective materials with a high thermal coefficient of expansion to be used for support functions such as, for example, circuit boards and ink manifolds. The flexible or floating mounting relieves shear stress cased by a differential in the expansion or contraction of materials having a different thermal coefficient of expansion.

Abstract: A wide semiconductor transducer device comprises a linear array of semiconductor chips. Each of the semiconductor chips has a plurality of transducer elements arranged on it along a front edge at a constant spacing, the constant spacing being maintained across the semiconductor chip boundaries. Each of the semiconductor chips also includes associated transducer circuits which are each connected one of the plurality of transducer elements formed on the semiconductor chip. While the requirement that the transducer elements maintain the constant spacing requires them to be located within a damage zone created during the dicing and/or thermally induced compression of the semiconductor chip, the associated transducer circuits can be located within an interior portion of the semiconductor chip. The interior portion of the semiconductor chip is located a sufficient distance from the edges of the semiconductor chip such that it does not encroach on the damage zone.

Abstract: An improved thermal ink jet printhead is formed by the alignment and bonding of an anisotropically etched silicon wafer channel plate, containing a plurality of channel grooves, to a silicon wafer heater plate, containing a plurality of heating and addressing elements which are covered by a patterned thin and thick film insulating layer. The printhead enables better bonding of the two plates by sequentially patterning each layer of a two layer thick film layer to compensate for topographical features formed in the last thick film layer. The relative thickness and geometrical shapes of the recesses in the two layers are selected, so that topographic formations are varied to prevent standoff between bonded heater and channel plates, thereby insuring that the adhesive applied between the bonded plates will have the greatest propensity to bond.

Abstract: An improved thermal ink jet printhead is formed by the alignment and bonding of an anisotropically etched silicon wafer channel plate, containing a plurality of channel grooves, to a silicon wafer heater plate, containing a plurality of heating and addressing elements which are covered by a patterned thick film layer. The printhead enables better bonding of the two plates by compensating for raised lips or edges formed on the outside edge of opposing last pits in an array of pits located in the thick film layer that are created while photofabricating the pits in the insulating layer. The fabrication sequence compensates for the raised edges by including a non-functional straddling channel that nullifies the standoff created by the raised edge and a corresponding additional non-functional pit that positions the raised edge away from the functional channels and nozzles.

Abstract: An ink jet printhead having off center or offset heaters or thermal transducers to reduce heater damage. The printhead has heaters located beneath channels to eject ink from the channel through a nozzle to a substrate for printing. Edge heaters are spaced away from the dicing edges of the heater plate to avoid damage resulting from dicing for assembly or from thermal expansion due to adjacent printheads if used to form a page width or large array printhead. The spacing distance between the edge heaters to adjacent equally spaced heaters on the same printhead is less than the distance between adjacent equally spaced heaters. Edge heaters are also offset from the centerline of respective channels in the printhead.

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 fixture for fabricating a full width scanning or imaging array from a plurality of relatively short subunits which provides immunity from vertical misalignment of the subunits caused by particle contamination. This is accomplished by providing a clearance slot in the fixture horizontal reference edge to minimize the reference edge and subunit contact area and to provide a space for the contaminating particles to accumulate so that they will not interfere with the precision placement and vertical alignment of the subunits on the fixture.

Abstract: A printhead for a thermal ink jet printer, preferably a roofshooter type printer, includes at least two arrays of linear spaced apart nozzles and heating elements, each array having a different resolution to produce printed pages at a draft print using a low resolution array, at a letter quality print using a high resolution array, or a combination of both arrays to provide enhanced grey scale reproduction. The high resolution array allows for accurate reproduction at a reduced throughput while the low resolution array allows for moderate reproduction at a higher throughput. Alternatively, the two arrays could be used simultaneously to provide a fast, broad, coarse stroke and a slower, fine detail stroke.

Abstract: A precision etched, three dimensional device is fabricated from a silicon wafer by etching from one side of the wafer. A chemical masking layer, such as silicon nitride, is first deposited on all sides of the wafer, followed by the deposition of a robust mechanical layer, such as polycrystalline silicon, over the masking layer on all sides of the wafer. The two layers are sequentially patterned on one side of the wafer and then the wafer is placed into an etchant bath which etches the exposed surface of the wafer and concurrently removes the protective layer, leaving a defect-free masking layer that prevents unintentional etching that would reduce yields of fabricated devices.

Abstract: A fabricating process for pagewidth reading and/or writing bars assembled from subunits, such as ink jet printhead subunits, is disclosed. At least two lengths of subunits are cut and placed on corresponding flat containers. An assembly robot places the subunits in a butted array on an alignment fixture and checks the accumulated positional error of the subunits as they are being assembled. When the robot detects an error exceeding some preset limits, it chooses a subunit of a known size to compensate for the detected error.

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: A pagewidth thermal ink jet printhead for an ink jet printer is disclosed. The printhead is the type assembled from fully functional roofshooter type printhead subunits fixedly mounted on the surface of one side of a structural bar. A passageway is formed adjacent the bar side surface containing the printhead subunits with openings provided between the passageway and the ink inlets of the printhead subunits, mounted thereon so that ink supplied to the passageway in the bar will maintain the individual subunits full of ink. The size of the printing zone for color printing is minimized because the roofshooter printhead subunits are mounted on one edge of the structural bar and may be stacked one on top of the other without need to provide space for the printhead subunits and/or ink supply lines. In addition, the structural bar thickness enables the bar to be massive enough to prevent warping because of printhead operating temperatures.

Abstract: A method of fabricating a semiconductor device having a buttable edge from a first wafer having first and second opposite planar surfaces and a second wafer having first and second opposite planar surfaces is disclosed. A first component is formed on the first planar surface of the first wafer. A precision dice cut is placed in the first planar surface of the first wafer closely adjacent to the first component. The precision dice cut extends partially through the first surface of the first wafer and defines the buttable edge. The first surface of the first wafer is bonded to the first surface of the second wafer, the first surface of the second wafer containing a second component and being aligned with and bonded to the first wafer so that the first and second components cooperate to form the semiconductor device. Portions of the first and second wafers surrounding the first and second components, respectively, are then removed to define the semiconductor device.