Abstract: An imaging device includes plurality of illumination elements interspersed among a plurality of light sensing elements so that each illumination element is adjacent to a light sensing element. The illumination elements each include a ferroelectric liquid crystal element positioned over a LED. The light sensing elements each include a photodiode. The illumination elements and the light sensing elements are arranged so that adjacent to each illumination element is a light sensing element. Illumination control logic can selectively illuminate each of the illumination elements. The light sensing elements are coupled to analog shift registers. The light sensing elements generate charges related to the intensity of the impinging light. Sensor control logic is used to load the charges generated by the light sensing elements corresponding to the illuminated illumination elements into the shift registers. The charge data in the shift registers is sequentially shifted to the input of an amplifier.

Abstract: An embodiment of a drying apparatus for drying ink deposited onto media includes an electromagnetic energy source to generate electromagnetic energy. The embodiment of the drying apparatus also includes a rectangular waveguide coupled to the electromagnetic energy source. The rectangular waveguide includes slots in the axial direction of the rectangular waveguide on opposite sidewalls corresponding to the largest sides forming a cross section of the rectangular waveguide. The electromagnetic energy source is configured to establish a TE01 mode within the rectangular waveguide, resulting in an electric field substantially perpendicular to the longitudinal axes of fibers within the media and thereby reducing power dissipated within the media while providing sufficient power for drying the ink during a drying operation.

Abstract: A media separator reduces the likelihood that multiple units of print media moved from an media tray will move through an imaging device. The media separator includes a separation member that is positioned by a position adjustment mechanism using output from a piezo electric sensor. A leading edge of the unit of print media moved from the media tray contacts the separation member. The angle between a plane of the unit of print media and a perpendicular to a tangent at a location the unit of print media contacts the surface of the separation member forms a contact angle. When multiple units of the print media are moved into the media path, a frictional force is exerted by the top unit of the print media upon the unit of print media below the top unit of print media. When the leading edge of the unit of print media below the top unit of print media contacts the separating member, a frictional force is exerted upon this unit of the print media by the separating member.

Abstract: A variable resolution transition placement circuit in an electrophotographic imaging device allows transitions to be placed within a stream of video data so that the pixel resolution achieved over a scan line is adjustable on a pixel by pixel basis using a system clock. Pixel data defines transition positions relative to a synthesized video clock defining pixel time periods. A converter converts positions of the transitions relative to the synthesized video clock to positions relative to the system clock using a value provided by a synthesized video clock to system clock transform generator. The value can change between synthesized video clock cycles to change the pixel resolution. A synthesized video generator generates values of a synthesized video clock relative to the system clock.

Abstract: An electrophotographic imaging device uses a transition placement device to position transitions in a stream of video data. A rasterizer included in the electrophotographic imaging device generates pixel data bytes based upon data received from a computer defining an image. A converter generates codes specifying positions of transitions within a pixel time period corresponding to a pixel data byte. The transition placement device includes a phase measuring device to measure a timing offset between an active edge of a beam detect signal and a rising edge of a reference clock. A transition adjustment device adjusts the positions of the transitions specified by the codes relative to the rising edge of the reference clock using the timing offset. Transition generation logic generates the transitions for the stream of video data using the adjusted transition positions received from the transition adjustment device.

Abstract: A temperature differential over a length of a fuser can result from a thermal load applied to the fuser by media having a dimension, corresponding to a longitudinal axis of the fuser, less then the length of the fuser. The temperature on regions of the surface of the fuser contacting the media is lower than on regions of the surface not contacting the media. With feedback used to control the fuser surface temperature near its center, the fuser surface temperature in regions not contacting the media can become hot enough to damage the fuser. With a heat pipe included in the fuser, heat flows from the higher temperature regions on the surface of the fuser to the lower temperature regions on the surface of the fuser, thereby reducing the peak magnitude of the fuser surface temperature and the magnitude of the temperature differential over the length of the fuser.

Abstract: A first embodiment of an illumination source including red LEDs, green LEDs, and blue LEDs provides illumination for a scanner. The LEDs are arranged in an array to generate spectrally and spatially substantially uniform illumination on the surface of an object, such as printed media, which is to be scanned. The arrangement of LEDs includes a plurality of groups of three LEDs. Each group of LEDs includes a red LED, a green LED, and a blue LED. The LEDs of like colors are connected in series. Power is supplied to the three groups of series connected LEDs by three current sources. The three current sources are each configured to supply a constant current to one of the groups of series connected LEDs. Each current source supplies a magnitude of current so that the resulting light provides substantially uniform illumination on the printed media.

Abstract: A fixing device bias control system compensates for variations in media resistivity by controlling a bias supplied to a fixing device, such as a fuser, in an electrophotographic imaging device. Media resistivity may change dependent upon on the environmental conditions to which the media is exposed. A reduction in the moisture content of the media, as occurs after the first pass of a duplex imaging operation or in low humidity environments, will significantly increase the media resistivity. An increase in the resistivity of the media can result in toner adhering to the fuser, causing contamination on the fuser and image defects. The fixing device bias control system supplies a bias, having the same polarity as the charge on the toner, to a fusing roller included in the fuser to repel the toner, thereby reducing fuser contamination and image defects. In a first embodiment, the fixing device bias control system controls the bias based upon exposure of the media to the fixing process.

Abstract: An embodiment of an edge placement device is supplied with transition data to generate transitions during a pixel time period corresponding to the transition data. The transition data is supplied by pulse code logic that converts pixel data to the transition data. The embodiment of an edge placement device includes first edge placement logic coupled to taps from a first clock delay chain and second edge placement logic coupled to taps of a second clock phase delay chain. Also included is a phase splitter that generate a first and a second clock phase coupled, respectively, to the first and the second clock delay chain from a clock corresponding to a pixel time period. The first and the second clock phase have rising edges on alternate cycles of the clock. The first and the second edge placement logic each include a plurality of D flip flops.

Abstract: A fixing device, such as a halogen bulb fuser or an instant on fuser, includes a first heating element supplied with substantially constant average power by a power control circuit in preparation for and during fusing. Additionally, the instant on fuser includes a second heating element supplied by the power control circuit. The power control circuit measures the average voltage across and the average current through the first heating element to detect changes in the thermal load applied to the first heating element. In preparation for fusing, the power control circuit applies sufficient power to the second heating element for fusing the expected average thermal load. If the power control circuit detects a level of thermal loading on the instant on fuser different than the expected average thermal load, the power control circuit adjusts the power supplied to the second heating element to compensate for the level of thermal loading different than the average expected thermal load.

Abstract: A first embodiment of an adjustment circuit for a laser diode output power compensator includes a feedback circuit for adjusting the laser diode output power compensator so that the output power of the laser diode is substantially constant. The feedback circuit includes a photodiode for measuring the output power of a VCSEL diode. The signal from the photodiode is coupled to a first amplifier. The difference between the signal from the photodiode and a first reference value is amplified and coupled through electronic switches to selectively charge one of multiple capacitors. The multiple capacitors are each coupled to one of a drive current source, a compensation current source, and a voltage controlled resistor, each of which are voltage controlled. A second amplifier is used for amplifying the difference between the signal from the photodiode and a second reference value to charge a capacitor coupled to a voltage controlled bias current source.

Abstract: An embodiment of a temperature monitoring system can be used to determine the temperatures of assemblies in an apparatus. The embodiment of the temperature monitoring system includes a sensor that can measure different types of gaseous molecules. The embodiment of the temperature monitoring system further includes a monitoring device coupled to the sensor to generate parameters based upon the quantities of the different types of gaseous molecules emitted by the assemblies. A controller coupled to the monitoring device determines the temperatures of the assemblies using the parameters generated by the monitoring device. If the controller determines that the temperatures of one or more of the assemblies exceeds a maximum desired operating temperature, the controller reduces the amount of energy dissipated in the assemblies to reduce the temperatures of the assemblies.

Abstract: An embodiment of a media quantity sensing device and a media type sensing device includes a first, a second a third, and a fourth electrode. The first electrode is positioned above a media tray and the second electrode is positioned on the media tray below the media. The third and the fourth electrodes are positioned so that the media leaving the media tray passes between them. The media quantity sensing device further includes a measuring circuit coupled to a controller. The measuring circuit includes a first dual slope integrator to generate a first square wave output signal having a frequency dependent upon the dielectric constant of the media between the first electrode and the second electrode. The measuring circuit further includes a second dual slope integrator to generate a second square wave output signal having a frequency dependent upon the dielectric constant of the media between the third electrode and the fourth electrode.

Abstract: A fixing device includes a compliant material positioned between a heating member and a support member. Cyclical heating of the fixing device induces differing amounts of thermal expansion in the support member and the heating member. Deformation of the compliant material reduces the thermally induced mechanical stresses that would have been experienced by the heating member had the heating member been rigidly attached to the support member. Reducing the thermally induced mechanical stresses experienced by the heating member reduces the likelihood of failure of the heating member resulting from fracturing of the heating member.

Abstract: Printing on a large number of units of relatively narrow media accelerates wear on a photoconductor in an electrophotographic imaging device, such as an electrophotographic printer. The accelerated wear results from movement of a cleaning blade over a surface of the photoconductor on regions of the photoconductor outside a width of the media where toner is not available as a lubricant. The accelerated wear also results from exposure of the surface of the photoconductor on regions of the photoconductor outside the width of the media to the electric fields supplied by a transfer roller. The accelerated wear can cause excessive background development on the photoconductor. Background development toner not transferred to the media is collected in the waste hopper. Excessive background development can lead to leakage of toner from the waste hopper into the electrophotographic printer.

Abstract: New interpolation techniques allow improved efficiency and speed in performing color space conversions. A radial interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by averaging a selected vertex value with the vertex values of each of the remaining vertices. A pruned radial interpolation technique employs a subset of the vertex values of the initially selected cube to generate the result of the interpolation, thereby improving upon the efficiency of the radial interpolation. A tetrahedral interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by applying a mathematical relationship which allows computation of sub-cube vertex values through a series of logical AND, logical OR and averaging operations.

Abstract: New interpolation techniques allow improved efficiency and speed in performing color space conversions. A radial interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by averaging a selected vertex value with the vertex values of each of the remaining vertices. A pruned radial interpolation technique employs a subset of the vertex values of the initially selected cube to generate the result of the interpolation, thereby improving upon the efficiency of the radial interpolation. A tetrahedral interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by applying a mathematical relationship which allows computation of sub-cube vertex values through a series of logical AND, logical OR and averaging operations.

Abstract: New interpolation techniques allow improved efficiency and speed in performing color space conversions. A radial interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Subcubes are generated by averaging a selected vertex value with the vertex values of each of the remaining vertices. A pruned radial interpolation technique employs a subset of the vertex values of the initially selected cube to generate the result of the interpolation, thereby improving upon the efficiency of the radial interpolation. A tetrahedral interpolation technique accomplishes an interpolation by generating successive subcubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Subcubes are generated by applying a mathematical relationship which allows computation of sub-cube vertex values through a series of logical AND, logical OR and averaging operations.

Abstract: An information collection system is used to improve the efficiency and accuracy of the collection of information for warranty database for printers. The system includes an information reading device attached to a computer system. Printer configuration and performance parameters which are to be collected are printed on a selftest page encoded as a bar code. In the preferred embodiment of the information collection system, the information reading device is a standard hand held bar code reader and the computer system is a portable computer. A windows based bar code reading utility is used to decode the data from the bar code reader. Information would be collected from the printer by printing a selftest page including the bar code, reading the bar code using the bar code reader, and storing the information decoded by the bar code reading utility on the hard disk drive of the computer system. At a later time, the data is transferred to the warranty database over a communications link such as a modem.

Abstract: New interpolation techniques allow improved efficiency and speed in performing color space conversions. A radial interpolation technique accomplishes an interpolation by generating successive subcubes. A value of a vertex of the final subcube generated is used as the result of the interpolation. Subcubes are generated by averaging a selected vertex value with the vertex values of each of the remaining vertices. A pruned radial interpolation technique employs a subset of the vertex values of the initially selected cube to generate the result of the interpolation, thereby improving upon the efficiency of the radial interpolation. A tetrahedral interpolation technique accomplishes an interpolation by generating successive subcubes. A value of a vertex of the final subcube generated is used as the result of the interpolation. Subcubes are generated by applying a mathematical relationship which allows computation of subcube vertex values through a series of logical AND, logical OR and averaging operations.