摘要:
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.In a second embodiment, a diffusion layer which is conformal is formed on the resistor surface with the PSG layer formed on the oxide layer. The diffusion layer can be a pyrolytic CVD deposited silicon nitride or a thermally grown oxide layer. The PSG layer has a planarized surface to which the tantalum conforms.
摘要:
A method for fabricating a coplanar full width scanning array from a plurality of relatively short scanning subunits for reading and writing images. The subunits are fixedly mounted in an end-to-end relationship on a flat structural member with the subunit surfaces containing the scanning elements all being coplanar even though at least some of the subunits have varying thickness. This is accomplished by forming from a photopatternable thick film layer one or more keys on the subunit surface having the scanning elements and associated circuitry and positioning the keys into keyways produced from a photopatternable thick film layer on a flat surface of an alignment fixture. A conformal adhesive bonds a structural member to the assembled subunits to form the full width scanning array.
摘要:
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.
摘要:
A printhead and method of fabrication thereof provides that the printhead reservoir has substantially the same cross-sectional ink flow area as the total cross-sectional area of the plurality of individual ink channels which interconnect the reservoir with the printhead nozzles. Since the flow area of the reservoir is substantially matched to the total flow area of the channels, the ink capacity of the reservoir is relatively low and the flow rate therethrough during a printing operation is relatively high. The small capacity of reservoir, together with the high ink flow rate therethrough, assures short ink residency time during printing, so that any exsolved air bubbles in the ink are swept away with subsequent ink droplet ejections during a printing operation and thus prevents any air bubbles present from coalescing into larger bubbles which can cause print quality defects.
摘要:
A printhead interposing maintenance method and apparatus are provided for maintaining a printhead assembly within a relatively tight space in an image producing machine. The printhead interposing maintenance apparatus for the method includes (a) at least a first home position adjacent a first side of four sides of an operating zone between a printhead assembly and an imaging surface in the image producing machine; (b) a first moving device for moving the printhead assembly from a printing first position adjacent the imaging surface to a maintaining second position spaced further away from the printing first position; (c) a maintenance apparatus movably supported for movement along an maintenance path interposed between the imaging surface and the printhead assembly; (d) a second moving device for moving the maintenance apparatus for contacting and maintaining the printhead assembly, and along the maintenance path from the at least first home position to a resting position adjacent a second side and opposite the first side of the four sides of the operating zone; and (e) a third moving device for moving the printhead assembly back from the maintaining second position to the printing first position.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.