Abstract: An ink jet printhead is disclosed which has a heater plate containing the heating elements and driving circuitry means monolithographically formed on one surface thereof and the ink flow directing channel structure is formed on the heater plate using a layer of patternable polymeric material which, in one embodiment, is exposed using a mask to define the channel pattern then developed and cured. After curing, the patterned channel structure is polished to provide a smooth coplanar surface and a cover plate with an aperture therein is aligned and bonded to the channel structure to complete the printhead. The aperture serves as both ink inlet and a portion of the ink reservoir. The channels are open at one end and serve as the droplet ejecting nozzles, while the other ends are closed and extend beneath the cover plate aperture to provide a baffled portion of the ink reservoir and prevent cross-talk between the ink channels.

Abstract: In an ejector for a thermal ink-jet printhead, a heating element exposing an area to liquid ink in the printhead includes an insulative layer around the lateral edges thereof, particularly those edges not having conductors associated therewith. This insulation creates a more uniform temperature distribution over the heating area, resulting in a uniform nucleation of a vapor bubble within the liquid ink.

Abstract: Raster scanner assemblies, and machines which use such raster scanner assemblies, which produce spots having a variable spot dimension. Raster scanner assemblies according to the present invention include an electronic subsystem which produces both image data and a spot size control signal, a laser assembly which produces a polarized laser beam having a beam with a first dimension and which is modulated in accord with the image data, a variable aperture assembly which changes the first dimension of the laser beam, a rotating polygon having a plurality of facets sweeping the laser beam in a sweep plane, and a scan lens for focusing the laser beam onto an image plane. The variable aperture assembly beneficially includes both a liquid crystal cell, which receives the laser beam and the spot size control signal, and a polarizing filter.

Abstract: A method is disclosed for bonding a nozzle plate to the front nozzle face of a printhead. A bonding station includes a heated printhead holder in opposed relationship to a nozzle plate holder with a curved lower surface. A nozzle plate having a row of nozzle holes and alignment apertures are formed by laser ablation in a thin polymer film. The film is moved into the bonding station, and the nozzle plate is aligned with pins on the curved nozzle plate holder surface. Both the printhead holder and nozzle plate holder are adjustable in directions perpendicular to the nozzle array on the printhead face and also rotationally. The adjustment insures that the nozzle plate, with adhesive applied to the bottom surface, makes initial tangential contact at the center of the nozzle array, resulting in accurate alignment of the nozzle plate holes with the nozzle array in the printhead face.

Abstract: A thermal ink-jet printhead includes ejectors wherein a heating surface is disposed within a channel retaining liquid ink. The heating element within each ejector includes a converter for converting applied electrical energy to heat energy, and a distributor, for distributing the heat energy over a portion of the heating surface. The structure of the heating element allows the effective area of nucleation within the heating area, the size of which directly affects the volume of the ejected liquid ink droplet, to be varied with voltage and/or pulse width.

Abstract: A method of accomplishing rotational alignment of laser arrays relative to an external optical axis is described. The method uses the laser polarization, which is oriented relative to the axis of the array, as the means of determining the laser array rotational orientation. The method can be rapidly executed in a manual or automatic procedure, has accuracy of better than 0.1 degree, and can be used to orient a laser array at any chosen angle with reflect to an external optical axis.

Abstract: There is provided an optical filtering system intended for use in a raster scanning arrangement for a document processing system. The document processing system includes a laser beam generating device providing a laser beam and a raster scanning device for transmitting the provided laser beam along a path. The optical filtering system includes a) an optical filter, disposed in the path, for reflecting the laser beam or permitting a portion of the laser beam to be transmitted therethrough, and b) a heating subsystem, thermally communicating with the optical filter, for maintaining the optical filter at a substantially fixed temperature.

Abstract: An ejector for a thermal ink-jet printhead includes a heating element defined on a main surface of a silicon heater chip. A cavity is disposed within the heater chip opposite the side of the heating element exposed to liquid ink. In one embodiment, the heating element is disposed on a narrow pillar which is surrounded by two elongated trenches. In another embodiment, the heating element is suspended over a cavity by narrow supports. In each case, the cavity reduces the thermal mass of the structure supporting the heating element and acts as an insulator to prevent excess heat from being dissipated into the body of the heater chip.

Abstract: The present invention is a multiple spot laser assembly, comprising a plurality of laser diodes, and a plurality of mounts, which include a support surface, upon which the laser diode are permanently affixed. The mounts, including the base plate and/or heat sink, further include a mating feature along an edge thereof for aligning a first mount with an adjacent mount, the two mounts abutting along at least one common edge. The mating features assure the accurate alignment of the laser diodes on the adjacent mounts when the mounts are assembled into a multispot laser light source.

Abstract: A document reproduction machine having an optical component which is coated with a low surface energy transparent coating to reduce the adhesion of particles on the optical component. During the forming of the coating the lateral conductivity of the coating is modified so as to dissipate electrical charge build up on the coating.

Abstract: The present invention presents an apparatus and method for efficiently and automatically monitoring the power output of laser diodes used to provide the scanning beams in a ROS system. Light radiated from the back facet of the laser diode is focused by a projection means, in a preferred embodiment, a ball lens onto a photosensor. The photosensor output is proportional to the power output of the diode associated with the photosensor. The use of a projection means provides immunity from stray light and from cross talk between closely positioned laser diodes in a multiple diode configuration and yield increase sensitivity of the photosensor.

Abstract: An optical element for the selective scan line skew correction in a raster output scanner (ROS) of an electrostatographic printer. The optical element includes a chamber having a volume defined by parallel surfaces in substantially parallel planes containing a liquid crystal material having a variable index of refraction as a function of voltage applied thereacross. An inhomogenous electric field is generated through the liquid crystal material to produce a refractive index gradient along substantially perpendicular planes in the optical element. The ROS includes a control and feedback system coupled to a variable voltage source for applying a variable biasing voltage across the optical element to control the variable index of refraction of the liquid crystal material for selectively correcting scan line skew.

Abstract: A test access port (TAP) controls monitoring and testing of static current IDDQ in integrated circuit (IC) devices having both a TAP of the type specified in IEEE Standard 1149.1 Test Access Port and Boundary Architecture and built-in current (BIC) monitors. BIC monitors are coupled between MOS or CMOS modules of the IC device and the low potential power rail (GND) for monitoring static current IDDQ. Bypass or shunt MOS transistors (N1,N2, . . . , NN) are coupled with primary current paths in parallel with the respective BIC monitors between the CMOS circuit modules and low potential power rail (GND). The TAP data registers (TDR's) include a design specific BIC shunt control TDR (BICSC TDR) constructed for receiving a coded BIC monitor bypass code (BICBC) at the TDI pin. BICSC TDR outputs are coupled to control nodes of the respective MOS bypass transistors (N1,N2, . . . , NN) for controlling the conducting state of the bypass transistors according to the BICBC.

Abstract: The present invention is a multispot laser light source assembled from at least two individual laser diodes in accordance with a design model. The multispot laser includes at least two semiconductor laser diodes, both of which are permanently affixed to a chip carrier. The chip carrier rigidly supports the diodes and conducts heat away from the the diodes to be dissipated by a heat sink. The present invention is further characterized by a predefined relationship between the chip carrier material, the relative dimensions of the chip carrier, and the separation distance of the diodes from the heatsink, which results in significant reduction in the thermal droop and crosstalk between the diodes.

Abstract: The present invention is directed to a method and apparatus for fabricating a dual beam semiconductor laser, wherein the laser includes first and second semiconductor laser dies respectively affixed to one another while separated by intervening alignment structures. The alignment structures provide accurate placement of the dual laser beams with respect to one another while also assuring thermal isolation of the laser diodes. The fabrication method employs photolithographic techniques to accurately position the alignment structures across an entire semiconductor wafer, thereby assuring accuracy in alignment of the assembled dual beam lasers. As a result, the need for multiple-step alignment operations commonly employed in the production of multiple diode laser devices is eliminated.

Abstract: A method and apparatus is provided for registration of color images on a photoreceptor belt. Registration is accomplished by forming, in one embodiment, a chevron-shaped registration marks in non-image areas of the belt. A Raster Output Scanner (ROS) sweeps an output beam across the belt's surface. The beam is modulated in accordance with input video data to form successive color images. An unmodulated beam is also swept across the registration marks, each mark being successively swept by a plurality of beams. With each crossing of the legs of the chevron, two signals are generated by an associated sensor and stored in an averaging and extrapolation circuit. The multiple signals are compared and detection of the intersection is calculated by an extrapolation method. The averaging circuitry generates a registration signal which is used to enable an accurate start of page signal, to correct for skew and to adjust for errors and line-to-line spacing between lines in a color image frame.

Abstract: An integrated circuit device ECL test access port (TAP) is constructed for low static current requirements and low power consumption when the TAP is inactive. The ECL test access port may conform with IEEE Standard 1149.1 Test Access Port and Boundary Scan Architecture. An SCS logic circuit (50) is incorporated in the TAP controller coupled to the flip-flops (32,34,36,38) of the TAP controller n state finite machine for generating a current sink switch control signal (SCS) according to the state of the TAP controller. A current sink switch circuit (24) is coupled to respective current sinks of ECL gates incorporated in the boundary scan register (BSR/TDR1), design specific TAP data registers (DS/TDRs), TAP instruction register (TIR), and device identification register (DIR/TDR3). The current sink switch circuit (24) has an input coupled to the SCS logic circuit (50) to receive the current sink switch control signal (SCS).

Abstract: In an overfilled ROS polygon architecture, stray reflection from facets adjacent the completely filled (illuminated) facet are neutralized by placing an optical isolator in the path of the unwanted stray reflections. In a first embodiment, the isolator comprises a linear polarizer and a quarter wave plate. In a second embodiment, the isolator comprises a liquid crystal quarter wave plate and a cholesteric liquid crystal cell.

Abstract: An optical element for the selective scan line skew correction in a raster output scanner (ROS) of an electrophotographic printer. The optical element includes a chamber containing a nematic material having a variable index of refraction as a function of voltage applied thereacross. The chamber has a volume defined by surfaces having progressively decreasing areas in substantially perpendicular planes. The ROS includes a control and feedback system coupled to a variable voltage source for applying a biasing voltage across the optical element to control the variable index of refraction of the nematic material for selectively correcting scan line skew.

Abstract: An optical element for the selective deflection of a scan line in a process direction in a raster output scanner (ROS) electrophotographic printer. The optical element includes a chamber containing a nematic liquid crystal material having a variable index of refraction as a function of voltage applied thereacross. The ROS includes a control and feedback system coupled to a variable voltage source for applying a biasing voltage across the optical element to control the variable index of refraction of the optical element for selectively deflecting the scan line in the process direction.