Patents Represented by Attorney R. Hutter

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  • Protocol for channel access in wireless or network data communication
    Patent number: 5721725
    Abstract: In a carrier sense multiple-access (CSMA) network, such as a wireless network or a LAN, a transceiver which initiates a transmission to a recipient transceiver in the same medium sends out, prefatory to a bulk of data, a field representative of the length of the data, and another field symbolic of the rate at which the data is to be sent. Non-participant transceivers in the medium receive the data length field and the data rate field, and calculate a length of time they must inhibit themselves to avoid a data collision with the transmitting transceiver, while the participants come to a common agreement at which they can send and receive data.
    Type: Grant
    Filed: October 30, 1995
    Date of Patent: February 24, 1998
    Assignee: Xerox Corporation
    Inventors: Roy Want, William N. Schilit, Richard J. Goldstein, Norman I. Adams
  • Security module for a printing apparatus
    Patent number: 5720012
    Abstract: A security module is operatively disposed at the hardware/software interface within a printing apparatus. The module is disposed along a connection which acts as a medium for command signals to operate the printer hardware, and for status signals to indicate physical conditions within the hardware. The security module facilitates security procedures which control aspects of printer operation, particularly the creation of MICR characters.
    Type: Grant
    Filed: January 27, 1997
    Date of Patent: February 17, 1998
    Assignee: Xerox Corporation
    Inventors: Michael J. McVeigh, Jose R. Diaz, Paul W. Eakin, Lawrence Meyer, George E. Marshall
  • Overcurrent protection for an ink-jet printhead
    Patent number: 5710689
    Abstract: A protection circuit prevents snapback events in MOS transistors associated with semiconductor or micromechanical structures, such as ink-jet ejectors. A bulk electrode associated with the MOS transistor is monitored for unusual high voltages which are consistent with an impending snapback event. The voltage on the bulk electrode is then used to turn on the control transistor which connects the gate of the MOS transistor to ground and thereby protects the device.
    Type: Grant
    Filed: June 24, 1996
    Date of Patent: January 20, 1998
    Assignee: Xerox Corporation
    Inventors: Juan J. Becerra, Sophie V. Vandebroek
  • Butted chip array with beveled chips
    Patent number: 5706176
    Abstract: In an array of butted silicon chips, as would be found in a full-page photosensitive scanner, ink-jet printhead, or LED exposure bar, individual silicon chips forming the array each define a planar bevel near the border of a neighboring chip. The planarity of the bevel avoids damage to the chips when the chips are placed in the chip array assembly.
    Type: Grant
    Filed: July 22, 1996
    Date of Patent: January 6, 1998
    Assignee: Xerox Corporation
    Inventors: Kraig A. Quinn, Brian T. Ormond
  • Thermal ink-jet printhead with a suspended heating element in each ejector
    Patent number: 5706041
    Abstract: In a thermal ink-jet printhead, a set of heating elements are formed in the main surface of a semiconductor chip. Channels are formed within the semiconductor chip underneath each of the heating elements, thereby exposing two main sides of each heating element within each ejector. Because two main surfaces of the heating element are accessible to liquid ink in each ejector, efficiency and thermal characteristics of the printhead are improved.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: January 6, 1998
    Assignee: Xerox Corporation
    Inventor: Joel A. Kubby
  • System for positioning an image in a digital printer
    Patent number: 5701151
    Abstract: A digital printing apparatus accepts image data in the form of PDL files, and also instructions, external to each PDL file, about shifting images formed at the PDL file to precise positions on a print sheet. The PDL file is interpreted to yield a raw bitmap, and then compressed according to a compression algorithm. The external shift instructions are then included in the compressed data as blank-line instructions which add a number of blank lines equal to a number of scan lines the image is desired to be shifted. The shifting is useful for accommodating bindings in the finished printed documents.
    Type: Grant
    Filed: October 30, 1995
    Date of Patent: December 23, 1997
    Assignee: Xerox Corporation
    Inventor: David Plakosh
  • Photosensitive silicon chip having a ridge near an end photosite
    Patent number: 5696626
    Abstract: A photosensitive chip, such as used in a scanner or facsimile, defines a linear array of photosites, each photosite being covered with a filter formed from a cured translucent liquid. At the critical ends of the chip, between the end photosite in the array and the edge of the chip, there is provided a ridge which protrudes over the thickness of the filter. This ridge maintains the physical integrity of the filter.
    Type: Grant
    Filed: October 12, 1995
    Date of Patent: December 9, 1997
    Assignee: Xerox Corporation
    Inventors: Paul A. Hosier, Jagdish C. Tandon, Josef E. Jedlicka, Brian T. Ormond
  • Photosensitive silicon chip having photosites spaced at varying pitches
    Patent number: 5691760
    Abstract: In a hard-copy scanner in which a set of photosensitive silicon chips are abutted to form a single page-width array of photosensors, the photosites at the critical ends of each chip are irregularly spaced, relative to the other photosites on the chip. This irregular spacing enables compensation for imprecisions in the dimensions of individual chips. The spacing principle can be applied as well to LED's or portions of ink-jet ejectors.
    Type: Grant
    Filed: October 12, 1995
    Date of Patent: November 25, 1997
    Assignee: Xerox Corporation
    Inventors: Paul A. Hosier, Jagdish C. Tandon
  • Ejector activation scheduling system for an ink-jet printhead
    Patent number: 5675365
    Abstract: An ink-jet printhead accepts a series of digital addresses as image data. Each digital address causes an individual ejector in the printhead having the particular address to be activated. The frequency of operation of the printhead can be directly related to the frequency at which addresses are submitted to the printhead. A scheduler polls image data for spot placements which require simultaneous activation of a plurality of ejectors in a set of interdependent ejectors, and then reschedules the activation of ejectors to avoid conflicts.
    Type: Grant
    Filed: September 13, 1995
    Date of Patent: October 7, 1997
    Assignee: Xerox Corporation
    Inventors: Juan J. Becerra, Christopher R. Morton, Thomas A. Tellier, David A. Mantell, Eduardo M. Freire
  • Semiconductor wafer divisible into chips for creating or recording images
    Patent number: 5668400
    Abstract: Semiconductor chips, such as photosensor arrays for a full-page-width scanner or printhead chips for a full-page-width ink-jet printer, are mounted on a substrate to maintain reasonably consistent spacing among adjacent chips. To remove a defective chip from the array, the substrate is urged evenly against a work surface defining a convex bow. Alternately, back-cuts are provided along abutting edges of the chips, and the silicon around these back-cuts can be sawed away to space defective chips from neighboring good chips. By increasing the spacing of a defective chip from neighboring chips, the defective chip can be removed while minimizing the risk of damage to neighboring chips. Also, batches of chips can be originally manufactured on a single wafer as either "regular" chips or "replacement" chips, with the replacement chips being slightly shorter in a critical dimension.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: September 16, 1997
    Assignee: Xerox Corporation
    Inventor: Kraig A. Quinn
  • Image rotation from virtual memory in a digital printing system
    Patent number: 5657431
    Abstract: In a high-speed digital printing apparatus having duplex capability, second-side images must be rotated. In order to quickly rotate the second-side images, the image data for the images are read out from memory in a reverse order of addresses, with each address corresponding to one byte. As each byte is transferred to an imager, a relationship of sets of bits, each set of bits corresponding to one pixel, are altered within each byte.
    Type: Grant
    Filed: June 3, 1996
    Date of Patent: August 12, 1997
    Assignee: Xerox Corporation
    Inventors: David Plakosh, Juan A. Romano, Frederic J. Stann, Guillermo Lao
  • System for determining a video offset from dark photosensors in an image sensor array
    Patent number: 5654755
    Abstract: In a photosensitive device wherein voltages are read sequentially from a dark, or dummy, photosensor and a plurality of active photosensors with each of a series of scans, a circuit downstream of the photosensors resets the offset value of the voltage signals, based on successive voltage readings from the dark photosensor. An RC circuit in parallel with the video line maintains a running average of readings from the dark photosensor over a large number of scans. This averaging of many dark-pixel readings averages out short-term thermal noise on the dark photosensor, for a truer offset value.
    Type: Grant
    Filed: January 5, 1996
    Date of Patent: August 5, 1997
    Assignee: Xerox Corporation
    Inventor: Paul A. Hosier
  • Drive circuit for high-speed modulation of a laser diode
    Patent number: 5651017
    Abstract: A drive circuit enables high-speed modulation of a laser diode. A transistor is associated with the laser diode. The transistor input is supplied with a constant bias current just below the lasing condition of the diode, and also to one or more switching currents which are shunted to the transistor input through Schottky diodes. This high-speed circuit can be used, for example, for modulating a writing beam in a "laser printer," or in a magnetic driver for a disk writer, or in fiber-optic communication.
    Type: Grant
    Filed: April 21, 1995
    Date of Patent: July 22, 1997
    Assignee: Xerox Corporation
    Inventor: Frank C. Genovese
  • High-speed output of video image data from an array of photosensors
    Patent number: 5638121
    Abstract: In a photosenstive device wherein video voltage signals are output from a plurality of photosensors, the photosensors are divided into odd and even subsets. Odd photosensors output video into an odd video channel, and even photosensors output video into an even video channel. The two video signals are time-staggered from each other by one-half cycle. The signals on the odd and even video channels are then multiplexed into a single high-speed channel.
    Type: Grant
    Filed: October 8, 1996
    Date of Patent: June 10, 1997
    Assignee: Xerox Corporation
    Inventors: Paul A. Hosier, Jagdish C. Tandon, Scott L. Tewinkle, David J. Metcalfe
  • Photosensitive chip having transfer circuits which compensate for shielded test photosensors
    Patent number: 5633679
    Abstract: A photosensitive device includes a plurality of active photosensors, for receiving light from an original image, and at least one dark photosensor. The dark photosensor is shielded with a light shield so that it receives no light, and is used to establish a dark offset for the device. Each active photosensor and the dark photosensor have associated therewith an individual transfer circuit, including a reset node having a capacitance associated therewith. The capacitance of the reset node for the dark photosensor is selected to compensate for the extra capacitance created by the light shield.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: May 27, 1997
    Assignee: Xerox Corporation
    Inventors: Paul A. Hosier, Jagdish C. Tandon
  • Decentralized tracking and routing system wherein packages are associated with active tags
    Patent number: 5627517
    Abstract: In a freight tracking and routing system, each individual package is provided with a tag physically attached thereto. The tag includes a radio or infrared transceiver, and a microprocessor. At important nodes at geographical locations within the distribution system, location transceivers broadcast signals representative of their locations. The microprocessor, in response to receiving a desired destination signal, emits a signal commanding external equipment to take the package so that it remains at the desired location. The tags are also capable of being electronically queried, or alternately can emit distress signals when they do not reach a particular location at a particular time.
    Type: Grant
    Filed: November 1, 1995
    Date of Patent: May 6, 1997
    Assignee: Xerox Corporation
    Inventors: Marvin M. Theimer, Roy Want
  • Ionographic printing with a focused ion stream controllable in two dimensions
    Patent number: 5617129
    Abstract: An ionographic printer directs a stream of ions from a source to a charge receptor to create an electrostatic latent image thereon. The ion stream passes through a relatively large aperture having associated therewith a focusing pinch electrode for narrowing the ion stream to a preselected width, displacing electrodes for positioning the narrowed ion stream within the aperture, and focus electrodes. Varying the biases of the displacing electrodes causes the ion stream to scan across the aperture to deposit multiple spots of charged areas at desired locations on the receptor. Varying the biases of the focus electrodes cures positional and ion-stream cross-section anomalies.
    Type: Grant
    Filed: October 27, 1994
    Date of Patent: April 1, 1997
    Assignee: Xerox Corporation
    Inventors: Joseph A. Chizuk, Jr., Richard F. Bergen, Robert W. Gundlach
  • Filter architecture for a photosensitive chip
    Patent number: 5604362
    Abstract: In a photosensitive chip suitable for full-color imaging, separate photosites on the chip correspond to different primary colors in an original image. Each primary-color photosite is filtered with a polyimide doped to a particular primary color. The red-filtering layer and the blue-filtering layer are left on the non-photosensitive portions of the main surface of the chip, and together serve as a non-reflective area which prevents stray reflections from the chip. The chip is further provided with a base layer of infrared-filtering polyimide.
    Type: Grant
    Filed: February 20, 1996
    Date of Patent: February 18, 1997
    Assignee: Xerox Corporation
    Inventors: Josef E. Jedlicka, Brian T. Ormond, Debra S. Vent
  • System for converting grayscale resolution in a printing apparatus
    Patent number: 5602579
    Abstract: A low-cost, high-speed system for converting high-grayscale-resolution image data to a grayscale resolution optimized for a particular output device, such as an LED bar or ink-jet printhead. A static random-access memory accepts at its address port a full image datum. The most significant digits of the datum relate to a look-up table selected for optimum performance in a given situation. The least significant digits of the datum represent the actual image datum. When the full image datum is applied to the address port, the address location identical to the full image datum outputs an output value which has been pre-loaded into the memory.
    Type: Grant
    Filed: September 6, 1994
    Date of Patent: February 11, 1997
    Assignee: Xerox Corporation
    Inventors: Samuel D. Ambalavanar, Anthony Frumusa, Kenneth D. Romano
  • Optimal toner concentration sensing system for an electrophotographic printer
    Patent number: 5600409
    Abstract: A maintenance method for a high-volume electrophotographic printer, in which an optimal toner/carrier (T/C) ratio for a primary toner supply is determined. The primary toner supply is first "stressed" to minimize the T/C therein, by developing a series of test patterns which include a series of narrow lines. Printing of narrow lines influences the proportion of relatively small toner particles in the toner supply. After this stressing, new toner particles are gradually introduced into the primary toner supply while a series of test patches is developed and the density of the test patches is monitored.
    Type: Grant
    Filed: February 20, 1996
    Date of Patent: February 4, 1997
    Assignee: Xerox Corporation
    Inventor: Matthew M. Dennie