Patents by Inventor Louis H. Chang

Louis H. Chang 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).

  • Control apparatus for serial printer
    Patent number: 4103766
    Abstract: A serial printer comprises a carriage, a print member rotatably mounted to the carriage and including a plurality of character elements, a first drive coupled to the print member for rotating the print member to a desired rotational position in order to place a selected character element at a printing position adjacent a record medium to be printed upon, a second drive coupled to the carriage for moving the carriage along a predetermined path whereby the print member is caused to move to a desired printing position along the path, a first servo control coupled to the first drive and responsive to a first set of input data and instructions for controlling the direction and speed of rotation of the print member, a second servo control system coupled to the second drive and responsive to a second set of input data and instructions for controlling the direction and speed of movement of the carriage, and a programmed data processor coupled to the first and second servo control system for supplying at least some of
    Type: Grant
    Filed: January 13, 1977
    Date of Patent: August 1, 1978
    Assignee: Xerox Corporation
    Inventors: Frank D. Ruble, Louis H. Chang, John C. Fravel
  • Control apparatus for serial printer
    Patent number: 4091911
    Abstract: A serial printer comprises a carriage, a print member rotatably mounted to the carriage and including a plurality of character elements, a first drive coupled to the print member for rotating the print member to a desired rotational position in order to place a selected character element at a printing position adjacent a record medium to be printed upon, a second drive coupled to the carriage for moving the carriage along a predetermined path whereby the print member is caused to move to a desired printing position along the path, a first servo control coupled to the first drive means and responsive to a first set of input data and instructions for controlling the direction and speed of rotation of the print member, second servo control means coupled to the second drive and responsive to a second set of input data and instructions for controlling the direction and speed of movement of the carriage, and a programmed data processor coupled to the first and second servo control system for supplying at least some
    Type: Grant
    Filed: May 3, 1976
    Date of Patent: May 30, 1978
    Assignee: Xerox Corporation
    Inventors: Louis H. Chang, John C. Fravel, Carl E. Herendeen, Frank D. Ruble
  • Increment-decrement logic for serial printer
    Patent number: 4058195
    Abstract: A serial printer comprises a carriage, a print member rotatably mounted to the carriage and including a plurality of character elements, a drive coupled to the print member for rotating the print member to a desired rotational position, a device coupled to the print member for generating a plurality of periodic position signals each indicative of the rotational movement of the print member, and a device for storing a count indicative of the actual rotational position of the print member, the device for storing including a device responsive to an increment pulse for incrementing the count by one and a device responsive to a decrement pulse for decrementing the count by one.
    Type: Grant
    Filed: May 3, 1976
    Date of Patent: November 15, 1977
    Assignee: Xerox Corporation
    Inventors: John C. Fravel, Louis H. Chang, Harunori Yoshikawa
  • Position retry apparatus for serial printer
    Patent number: 4037216
    Abstract: A serial printer comprises a carriage, a print member rotatably mounted to the carriage, drive means coupled to the print member for rotating the print member in a desired direction and at a desired speed, and control apparatus coupled to the drive means for generating a control signal to control the direction and speed of rotation of the print member.
    Type: Grant
    Filed: May 3, 1976
    Date of Patent: July 19, 1977
    Assignee: Xerox Corporation
    Inventors: Louis H. Chang, John C. Fravel
  • Signal priority logic for serial printer
    Patent number: 4035781
    Abstract: In a serial printer comprising a carriage movable along a predetermined path, a print member rotatably mounted to the carriage and including a plurality of character elements, first drive means coupled to the print member for rotating the print member to a desired rotational position, second drive means coupled to the carriage for moving the carriage to a desired position along the path, and control apparatus coupled to the first drive means for controlling the direction and speed of rotation of the print member and coupled to the second drive means for controlling the direction and speed of movement of the carriage, the control apparatus comprising first means for receiving and storing a first signal indicative of the desired rotational position of the print member, second means for receiving and storing a second signal indicative of the desired linear position of the carriage, means coupled to the first and second means for receiving and storing for generating a third signal if the first signal was received
    Type: Grant
    Filed: May 3, 1976
    Date of Patent: July 12, 1977
    Assignee: Xerox Corporation
    Inventor: Louis H. Chang