Patents by Inventor Y. Grant Chang

Y. Grant 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).

  • Patent number: 6896429
    Abstract: An ink density closed loop control system for an ink ribbon of an impact printer having a reservoir roller formed of an ink absorbent material with at least one or more channels within the reservoir roller fluidly connected to a pump and ink supply. A transfer roller can contact the reservoir roller for imparting ink to the ink ribbon. A sensor senses the relative amount of ink on the print ribbon and an electrical drive responsive to the sensor drives the pump for a flow of ink to the one or more channels. The sensor can sense ink on different segments of the ribbon and, with two or more channels in the reservoir roller can distribute ink to two or more segments of the reservoir roller depending upon the ink sensed at a particular segment of the ribbon. A further enhancement of this invention provides a multi-viscosity ink to compensate for changes in ambient temperature conditions.
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: May 24, 2005
    Assignee: Printronix, Inc.
    Inventors: Dennis R. White, Jeng-Dung Jou, Gordon B. Barrus, Y. Grant Chang, John W. Gemmell, John S. Kinley, Lihu Chiu, Kevin P. Moore
  • Publication number: 20040179881
    Abstract: An ink density closed loop control system for an ink ribbon of an impact printer having a reservoir roller formed of an ink absorbent material with at least one or more channels within the reservoir roller fluidly connected to a pump and ink supply. A transfer roller can contact the reservoir roller for imparting ink to the ink ribbon. A sensor senses the relative amount of ink on the print ribbon and an electrical drive responsive to the sensor drives the pump for a flow of ink to the one or more channels. The sensor can sense ink on different segments of the ribbon and, with two or more channels in the reservoir roller can distribute ink to two or more segments of the reservoir roller depending upon the ink sensed at a particular segment of the ribbon. A further enhancement of this invention provides a multi-viscosity ink to compensate for changes in ambient temperature conditions.
    Type: Application
    Filed: December 18, 2003
    Publication date: September 16, 2004
    Inventors: Dennis R. White, Jeng-Dung Jou, Gordon B. Barrus, Y. Grant Chang, John W. Gemmell, John S. Kinley, Lihu Chiu, Kevin P. Moore
  • Patent number: 6695495
    Abstract: An ink density closed loop control system for an ink ribbon of an impact printer having a reservoir roller formed of an ink absorbent material with at least one or more channels within the reservoir roller fluidly connected to a pump and ink supply. A transfer roller can contact the reservoir roller for imparting ink to the ink ribbon. A sensor senses the relative amount of ink on the print ribbon and an electrical drive responsive to the sensor drives the pump for a flow of ink to the one or more channels. The sensor can sense ink on different segments of the ribbon and, with two or more channels in the reservoir roller can distribute ink to two or more segments of the reservoir roller depending upon the ink sensed at a particular segment of the ribbon. A further enhancement of this invention provides a multi-viscosity ink to compensate for changes in ambient temperature conditions.
    Type: Grant
    Filed: March 12, 2003
    Date of Patent: February 24, 2004
    Assignee: Printronix, Inc.
    Inventors: Dennis R. White, Jeng-Dung Jou, Lihu Chiu, Gordon B. Barrus, Y. Grant Chang
  • Patent number: 6478487
    Abstract: An impact printer such as a line printer having a base with a hammerbank mounted on the base driven for reciprocal movement. The hammerbank has a plurality of hammers with printing tips formed on frets in two longitudinally oriented rows defining an upper row and a lower row. A permanent magnet with pole pieces retains the hammers until a coil overcomes the magnetic retention. A print ribbon is impacted by the printing tips of the impact printer such as a line printer against a print media. The print ribbon has a first longitudinal high strike zone of ink of greater print yield with a low strike zone of lesser print yield on either side of the first zone. The print yield can be a factor of ink viscosity, pigment content, fabric content, fabric composition, or dye features.
    Type: Grant
    Filed: June 22, 2001
    Date of Patent: November 12, 2002
    Assignee: Printronix, Inc.
    Inventors: Jeng-Dung Jou, Y. Grant Chang
  • Patent number: 6423155
    Abstract: A new high strength steel alloy characterized by having high DC magnetic saturation, ultra high tensile, yield and fatigue strengths that is particularly suited for use as a hammerspring in hammerbanks in impact printers and for other applications where magnetic alloys are used and high mechanical strength is desirable. The alloy is formed of the following composition in weight percent: about 20% to about 35% Co; about 2% to about 6.0% Ni; about 0.0 to about 0.15% C; about 0.75% to about 3% Mo; 0% to about 3.0% Cr; 0% to about 2% Mu; 0% to about 0.02% Si; 0% to about 0.003% P; 0% to about 0.001% S; 0% to about 0.005% 02+N2;with the balance comprised of Fe. A process for making the alloy includes homogenizing preferably at a temperature of 2150° F. for 24 hours, and solution treating at a temperature in the range of about 1500° F. to about 1700° F. under a vacuum or inert gas protective atmosphere; air-cooling; and precipitation aging at a temperature in the range of about 800° F.
    Type: Grant
    Filed: August 29, 2000
    Date of Patent: July 23, 2002
    Assignee: Printronix, Inc.
    Inventors: Y. Grant Chang, Norman E. Farb
  • Patent number: 6244768
    Abstract: A line printer with a hammerbank having print hammers with printing tips and a ribbon supported for impact by the tips for printing on media and a metal platen for supporting the media. An elastomer on the metal platen supports the media and has a layer of material harder than the elastomer extending inwardly from its surface which receives the impacts of the hammer tips. The harder material can be particles extending inwardly randomly from the surface of the elastomer of a ceramic having a sphericity exceeding 0.50 up to 35 percent of the thickness of the elastomer, and in the range of 20 microns to 400 microns in size.
    Type: Grant
    Filed: March 2, 1999
    Date of Patent: June 12, 2001
    Assignee: Printronix, Inc.
    Inventors: Y. Grant Chang, Norman E. Farb
  • Patent number: 6146033
    Abstract: A new high strength steel alloy characterized by having high DC magnetic saturation, ultra high tensile, yield and fatigue strengths that is particularly suited for use as a hammerspring in hammerbanks in impact printers and for other applications where magnetic alloys are used and high mechanical strength is desirable. The alloy is formed of the following composition in weight percent: about 20% to about 35% Co; about 2% to about 6.0% Ni; about 0.0 to about 0.15% C; about 0.75% to about 3% Mo; 0% to about 3.0% Cr; 0% to about 2% Mn; 0% to about 0.02% Si; 0% to about 0.003% P; 0% to about 0.001% S; 0% to about 0.005% O.sub.2 +N.sub.2 ; with the balance comprised of Fe.A process for making the alloy includes homogenizing preferably at a temperature of 2150.degree. F. for 24 hours, and solution treating at a temperature in the range of about 1500.degree. F. to about 1700.degree. F. under a vacuum or inert gas protective atmosphere; air-cooling; and precipitation aging at a temperature in the range of about 800.
    Type: Grant
    Filed: June 3, 1998
    Date of Patent: November 14, 2000
    Assignee: Printronix, Inc.
    Inventors: Y. Grant Chang, Norman E. Farb