Patents by Inventor Frederick A. Donahue

Frederick A. Donahue has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5803628
    Abstract: A printing apparatus and method for printing on a recording medium at locations being determined by encoder pulses of an encoder signal generated by an encoder including an encoder pending circuit. The encoder pending circuit outputs an encoder pending signal indicating the generation of one of the encoder pulses during a current printing operation. A controller coupled to the encoder pending circuit, receives the encoder pending signal and generates an enable signal after the completion of the current printing operation. The method of printing includes receiving one of the encoder pulses; determining whether the received one of the encoder pulse is generated during a current printing operation and completing the current printing operation before responding to the received one of the encoder pulses.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: September 8, 1998
    Assignee: Xerox Corporation
    Inventor: Frederick A. Donahue
  • Patent number: 5704602
    Abstract: In reproduction systems in which a printer outputs a plurality of different plural sheet print jobs to a common stacking output, a system is provided for automatically separating respective print jobs into separate folders by loading selected folder paper stock into a paper source for the reproduction system, automatically feeding the folder paper stock to the same print jobs stacking output in the correct sequence with the feeding of the copy sheets of the print jobs, providing an open folder at the print jobs stacking output in a position to receive the copy sheets therein prior to the print job, then feeding the plural printed copy sheets of the print job into the open folder, closing the open folder around the print job, repeating the process for subsequent folders and their respective print jobs and stacking them substantially superposed in the common print jobs stacking output, with the closed folders providing clear distinctions and separations of the respective print jobs within their respective folde
    Type: Grant
    Filed: October 18, 1996
    Date of Patent: January 6, 1998
    Assignee: Xerox Corporation
    Inventors: Thomas N. Taylor, Frederick A. Donahue, Robert A. Panos
  • Patent number: 5692108
    Abstract: A method and apparatus for checkerboard printing by a liquid ink printing apparatus. A liquid ink printing apparatus, such as a thermal ink jet printer, includes circuitry for reducing video data clocking in checkerboard printing by controlling the odd and even vertical print strokes of a reciprocating printhead mounted to a scanning carriage. The amount of bitmapped imaged data, also known as video data, is reduced by one half or more and sent to the printhead for printing checkerboard patterns. Reduction of the bitmapped image data is accomplished by a data packer circuit which selects certain bits of the bitmapped image data for printing by the printhead in a checkerboard pattern. At the printhead, the bitmapped image is reconstructed by a data unpacker circuit to cause selective ejection of ink from the appropriate nozzles of the printhead. Two or more passes information are printed to complete printing of the bitmapped image data.
    Type: Grant
    Filed: September 26, 1994
    Date of Patent: November 25, 1997
    Assignee: Xerox Corporation
    Inventor: Frederick A. Donahue
  • Patent number: 5619622
    Abstract: A full width array raster imaging interface for an ink jet printer. The raster imaging interface transforms raster information for printing by a thermal ink jet full width array printbar. The transformation includes dividing scan lines of the raster information into segments corresponding to the number of die in a printbar and to delay the printing of each subsequent segment by one scan line. The transformation is necessary since the printbar prints a single line of pixels in a burst of several banks or segments having a plurality of nozzles. The banks of nozzles are fired sequentially and the nozzles within a bank are fired simultaneously.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: April 8, 1997
    Assignee: Xerox Corporation
    Inventors: Anthony E. Audi, Frederick A. Donahue
  • Patent number: 5579453
    Abstract: A smart direct memory access controller for data space transformation. The smart direct memory access controller can be used in computer systems to read and/or write data in a non-linear fashion in order to alter the organization of data stored within the computer system. The direct memory access controller has particular application in the electronic subsystem of a non-raster format electronic printer, such as a partial width array or full width array thermal ink jet printer. The smart direct memory access controller enables a non-raster format printer to access image organized in raster format, by viewing the data space as a non-linear or multi-dimensional memory. Memory addresses of the non-linear or multi-dimensional address space are a catenation of several data fields. Each field is one of the coordinates that defines the location of data within memory.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: November 26, 1996
    Assignee: Xerox Corporation
    Inventors: William M. Lindenfelser, Frederick A. Donahue, Anthony E. Audi
  • Patent number: 5563591
    Abstract: A programmable encoder having an addressable display device to display an encoder pattern of fiducial marks. The programmable encoder can be programmed to display an encoder pattern on a liquid crystal display. A sensor senses the marks on the pattern and generates sensor signals indicative of the sensed pattern. A controller connected to the sensor receives the sensor signals and outputs control signals which control the movement of a machine, such as an ink jet printer. The programmable encoder can be programmed to display any number of patterns on the addressable display device, and consequently, is highly adaptable to any number of applications requiring position, speed, or acceleration control.
    Type: Grant
    Filed: October 14, 1994
    Date of Patent: October 8, 1996
    Assignee: Xerox Corporation
    Inventors: Kurt L. Jacobs, Hugh L. Fuller, Frederick A. Donahue
  • Patent number: 5534895
    Abstract: A method and apparatus for automatically adjusting the quality of printing made by a scanning type printhead or printbar upon a recording medium advanced perpendicularly to the scanning direction. The scanning printbar includes sequentially printed segments in which the dots or pixels in a segment are printed simultaneously. A source of illumination is passed across a test pattern having features indicative of printhead alignment and discernible under the illumination. The source of illumination is connected to circuitry with determines the variation in light intensity of the test pattern. A value indicative of the misalignment is calculated and used to correct the timing of firing signals between the sequentially fired banks of nozzles of a printbar.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: July 9, 1996
    Assignee: Xerox Corporation
    Inventors: William M. Lindenfelser, Frederick A. Donahue
  • Patent number: 5402156
    Abstract: A translatable information transfer device, such as ink jet printhead, is stepwise advanced by a mechanism consisting of a lead screw axially spring biased at one end, cam surface provided at the other end of the lead screw, fixed cam follower which engages the cam surface, and a carrier for the information transfer device mounted on the lead screw with cooperating internal threads. Rotation of the lead screw does not advance the carrier having the information transfer device until after one complete revolution of the lead screw, whereupon the cam surface and cam follower permit the information transfer device to axially advance a predetermined distance, such as, for example, one printing swath.
    Type: Grant
    Filed: June 29, 1992
    Date of Patent: March 28, 1995
    Assignee: Xerox Corporation
    Inventors: Frederick A. Donahue, Paul J. Rowe
  • Patent number: 5349905
    Abstract: A thermal ink jet printer incorporates a copy speed feed control for reducing peak power requirements. Printing data supplied to the printer is scanned to determine image density or power consumption to dry ink in a dryer is determined. The speed of the sheet transport system is controlled in accordance with the image density so that, at high image densities, the speed of the sheet at the printer and/or at the dryer is reduced. A controller controls the speed of a drive motor driving the transport system in accordance with a determination of the density of the printed image from image print data or energy required for ink drying. A printer employing on-demand workstations having potentially high peak power usages can be made compatible with conventionally provided power supply systems.
    Type: Grant
    Filed: April 5, 1993
    Date of Patent: September 27, 1994
    Assignee: Xerox Corporation
    Inventors: Thomas N. Taylor, Frederick A. Donahue
  • Patent number: 4577096
    Abstract: A sheet detector having an emitter (lamp), detector (phototransistor), operational amplifier and an RC network. As contamination is deposited on the emitter or detector, a feedback loop provides more drive to the lamp providing sufficient drive to hold the emitter of the phototransistor at its desired stage. As a first copy paper is passed between the emitter and detector, the RC network of a common mode operational amplifier detects a change and generates an output. As a subsequent sheet enters the system, the transmissibility abruptly changes again causing the common mode operational amplifier to provide a subsequent pulse indicating the presence of a multiple feed.
    Type: Grant
    Filed: August 15, 1983
    Date of Patent: March 18, 1986
    Assignee: Xerox Corporation
    Inventors: Jack Beery, Frederick A. Donahue, Ronald E. Shaul