Patents by Inventor John C. H. Chang

John C. 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).

  • Patent number: 6162485
    Abstract: A system for forming fingerprints comprises a substrate bearing a designated print image-forming area and a localized coating of pressure-sensitive microcapsules containing a substantially colorless, image-forming reactant in the form of a color former or color-developer for forming a latent or visible image of a fingerprint in the designated print image-forming area. An image-developing device comprising a transparent film coated with a dual-functional adhesive composition comprising a pressure-sensitive adhesive containing an image-forming co-reactant in the form of a color developer or color former is used to form a protected visible image in the designated print image-forming area when applied to the fingerprint image.
    Type: Grant
    Filed: May 7, 1998
    Date of Patent: December 19, 2000
    Assignee: Wallace Computers Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 6060428
    Abstract: A document capable of providing information under the application of heat, which comprises a first support having a first surface and a second surface, the first surface bearing an information area including a visible principal image, and at least one of said first support or second support bearing at least one localized coating comprising a substantially colorless, non-pressure sensitive, heat-activatable chromogenic composition capable of producing a first color under the application of heat, the chromogenic composition comprising a chromogenic compound and a color developer. The chromogenic compound and the color developer are substantially colorless solids in physical contact prior to reaction, but which can chemically react to produce a visible colored image by application of heat at temperatures above room temperature.
    Type: Grant
    Filed: May 7, 1998
    Date of Patent: May 9, 2000
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Donald J. Hoffmann, Ronald R. Garrison, Derrick Kraus
  • Patent number: 5970875
    Abstract: A tamper evident document for use with an impact printer having an inked ribbon, which document comprises, a substrate having a first surface and a second surface, the first surface being adapted to receive a principal visible colored image by transfer from the inked ribbon of an impact printer and being substantially free from color forming compositions which react to form visible colored images, the second surface being coated with a self-contained pressure-sensitive chromogenic composition capable of reacting to form a visible colored mirror image on the second surface, the substrate being sufficiently translucent such that the second visible colored mirror image could be viewed from the first surface, if said second visible image were not totally blocked by said principal visible image, so as to determine whether the principal and second visible colored mirror images are in register.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: October 26, 1999
    Assignee: Wallace Computer Services, Inc.
    Inventors: Donald J. Hoffmann, John C. H. Chang
  • Patent number: 5898017
    Abstract: A heat-sensitive document capable of providing multiple colors comprising a support having at least one surface bearing a first coating comprising a substantially colorless, chromogenic composition which is capable of producing a first color, a second coating covering a portion of the first coating, the second coating being an opaque coating, comprising an opacifying agent and a hydrophobic, polymeric binding agent, and a localized third coating covering at least a portion of said second coating comprising a substantially colorless, heat-activatable chromogenic composition capable of producing a second color, preferably under the application of heat. The opaque coating is "dual-functional", since it both enhances multicolor image quality and acts as a primer for adhering the localized chromogenic coating composition.
    Type: Grant
    Filed: August 19, 1997
    Date of Patent: April 27, 1999
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5880063
    Abstract: Coverage of a chromogenic reaction product over a substrate is improved by incorporating a color developer in the substrate and coating the substrate with a color former to form a colored reaction product.
    Type: Grant
    Filed: March 6, 1997
    Date of Patent: March 9, 1999
    Assignee: Wallace Computer Services, Inc.
    Inventors: Donald J. Hoffman, John C. H. Chang
  • Patent number: 5759327
    Abstract: A business form comprising a substrate with at least one surface bearing a dual-functional coating comprising a copolymer of ethylene and vinyl acetate containing at least 40 weight percent ethylene and having a softening point of at least 60.degree. C. enhances adhesion of toner particles and is self-adhering under application of heat and pressure.
    Type: Grant
    Filed: May 7, 1996
    Date of Patent: June 2, 1998
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5644352
    Abstract: A document capable of providing multiple colors under the application of heat comprising a support having at least one surface bearing a first coating comprising a substantially colorless, heat activatable chromogenic composition capable of producing a first color under the application of heat, and a second coating comprising a localized coating of a substantially colorless, heat activatable chromogenic composition capable of producing a second color under the application of heat. Each chromogenic composition comprises a chromogenic compound and a color developer that are substantially colorless solids in physical contact prior to reaction, but which can chemically react to produce a visible colored image by application of heat at temperatures above room temperature. Under the application of heat from a thermal printer, by quickly striking the chromogenic composition with a fingernail or blunt object to produce frictional heat, or other heat application, multicolored images are provided.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: July 1, 1997
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Eric B. Wendler, Vance P. Gregory, Jr.
  • Patent number: 5618063
    Abstract: A document capable of providing multiple colors under the application of heat comprising a support having at least one surface bearing a first coating comprising a substantially colorless, heat activatable chromogenic composition capable of producing a first color under the application of heat, and a second coating comprising a localized coating of a substantially colorless, heat activatable chromogenic composition capable of producing a second color under the application of heat. Each chromogenic composition comprises a chromogenic compound and a color developer that are substantially colorless solids in physical contact prior to reaction, but which can chemically react to produce a visible colored image by application of heat at temperatures above room temperature. Under the application of heat from a thermal printer, by quickly striking the chromogenic composition with a fingernail or blunt object to produce frictional heat, or other heat application, multicolored images are provided.
    Type: Grant
    Filed: April 4, 1995
    Date of Patent: April 8, 1997
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Eric B. Wendler, Vance P. Gregory, Jr.
  • Patent number: 5612541
    Abstract: An ultraviolet radiation monitoring kit comprising at least one first substrate and at least one second substrate, the second substrate being capable of being closely associated with at least one first substrate, the first substrate having an indicator area comprising a chromogenic composition, the chromogenic composition comprising (a) the colored reaction product of a chromogen and a color developer, the colored reaction product being capable of changing color when exposed to ultraviolet radiation, or (b) a substantially colorless mixture of a chromogen and a color developer capable of reacting to form color when exposed to ultraviolet radiation, the second substrate bearing a reference color chart, the reference color chart comprising at least one reference color corresponding to time exposure to ultraviolet radiation, such that comparison of the color developed by the chromogenic composition upon exposure to ultraviolet light with a reference color provides an indication of the time and degree of exposure
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: March 18, 1997
    Assignee: Wallace Computer Services, Inc.
    Inventors: Donald J. Hoffmann, John C. H. Chang
  • Patent number: 5605873
    Abstract: A pressure-sensitive, laser printer heat-resistant verification system for preventing unauthorized photoduplication of security documents comprising a support bearing an information area comprising a visible principal image, and a verification area comprising a localized, autogenous coating of a pressure-sensitive chromogenic composition for producing a visible colored image by external pressure. The chromogenic composition comprises (a) pressure-rupturable microcapsules containing a chromogen and (b) a color developer capable of reacting with the chromogen to form a visible image. The pressure-rupturable microcapsules and color developer are substantially coextensive on the support, and the verification area is spaced apart from the information area.
    Type: Grant
    Filed: October 6, 1994
    Date of Patent: February 25, 1997
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5595955
    Abstract: A pressure and heat-sensitive composition comprising chromogen-containing pressure-rupturable microcapsules and heat-sensitive color developer useful for verification of document authenticity system when applied as a localized coating on documents, such as checks and prescriptions. Quickly striking the chromogenic composition with a fingernail or blunt object to generate pressure and heat in the coating produces a colored image by friction. The chromogenic composition possesses a fugitive characteristic, whereby the colored image gradually disappears and can be made to reappear when the chromogenic coating is again subjected to external pressure and heat. This feature can be used for repeated verification of the authenticity of the document.
    Type: Grant
    Filed: November 16, 1994
    Date of Patent: January 21, 1997
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Richard H. Johnson
  • Patent number: 5545459
    Abstract: A business form comprising a substrate with at least one surface bearing a dual-functional coating comprising a copolymer of ethylene and vinyl acetate containing at least 40 weight percent ethylene and having a softening point of at least 60.degree. C. enhances adhesion of toner particles and is self-adhering under application of heat and pressure.
    Type: Grant
    Filed: January 20, 1995
    Date of Patent: August 13, 1996
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5536046
    Abstract: A heat sensitive system comprises a document having a localized, non-pressure sensitive, coating of chromogenic composition activated at moderate temperatures. Quickly striking the chromogenic composition with a fingernail or blunt object produces a colored image by frictional heat. The chromogenic composition contains a chromogenic compound and a color developer which are non-pressure sensitive and nonreactive at room temperature. The chromogenic composition can be an intimate mixture of the chromogenic compound and the developer or alternatively separate layers of each of the components.
    Type: Grant
    Filed: February 17, 1995
    Date of Patent: July 16, 1996
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5484169
    Abstract: A hidden entry system comprises a document having a first substrate bearing a localized latent image spaced apart from a removable image-developing device comprising a second substrate having a first surface and a second surface, the first surface of the second substrate bearing a chromogenic composition comprising an image-forming co-reactant, the image-forming co-reactant being a chromogen or a color developer, the second surface of the second substrate bearing a pressure-sensitive adhesive. The image developing device is in superposed relation with the first substrate with the pressure sensitive coating being releasably attached to the first substrate.
    Type: Grant
    Filed: February 17, 1995
    Date of Patent: January 16, 1996
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Donald Hoffmann
  • Patent number: 5431452
    Abstract: A hidden entry system comprises a document having a first substrate bearing a localized latent image spaced apart from a removable image-developing device comprising a second substrate having a first surface and a second surface, the first surface of the second substrate bearing a chromogenic composition comprising an image-forming co-reactant, the image-forming co-reactant being a chromogen or a color developer, the second surface of the second substrate bearing a pressure-sensitive adhesive. The image developing device is in superposed relation with the first substrate with the pressure sensitive coating being releasably attached to the first substrate.
    Type: Grant
    Filed: August 23, 1993
    Date of Patent: July 11, 1995
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Donald Hoffmann
  • Patent number: 5427415
    Abstract: A heat sensitive system comprises a document having a localized, non-pressure sensitive, coating of chromogenic composition activated at moderate temperatures. Quickly striking the chromogenic composition with a fingernail or blunt object produces a colored image by frictional heat. The chromogenic composition contains a chromogenic compound and a color developer which are non-pressure sensitive and non-reactive at room temperature. The chromogenic composition can be an intimate mixture of the chromogenic compound and the developer or alternatively separate layers of each of the components.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: June 27, 1995
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5401060
    Abstract: A pressure and heat-sensitive composition comprising chromogen-containing pressure-rupturable microcapsules and heat-sensitive color developer useful for verification of document authenticity system when applied as a localized coating on documents, such as checks and prescriptions. Quickly striking the chromogenic composition with a fingernail or blunt object to generate pressure and heat in the coating produces a colored image by friction. The chromogenic composition possesses a fugitive characteristic, whereby the colored image gradually disappears and can be made to reappear when the chromogenic coating is again subjected to external pressure and heat. This feature can be used for repeated verification of the authenticity of the document.
    Type: Grant
    Filed: June 14, 1993
    Date of Patent: March 28, 1995
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Richard H. Johnson
  • Patent number: 5395138
    Abstract: A pressure-sensitive, laser printer heat-resistant verification system for preventing unauthorized photoduplication of security documents comprising a support bearing an information area comprising a visible principal image, and a verification area comprising a localized, autogenous coating of a pressure-sensitive chromogenic composition for producing a visible colored image by external pressure. The chromogenic composition comprises (a) pressure-rupturable microcapsules containing a chromogen and (b) a color developer capable of reacting with the chromogen to form a visible image. The pressure-rupturable microcapsules and color developer are substantially coextensive on the support, and the verification area is spaced apart from the information area.
    Type: Grant
    Filed: June 14, 1993
    Date of Patent: March 7, 1995
    Assignee: Wallace Computer Services, Inc.
    Inventor: John C. H. Chang
  • Patent number: 5344191
    Abstract: A hidden entry system comprises a document having a localized coating of a non-pressure sensitive heat activated autogenous chromogenic composition to provide a latent image which reveals hidden indicia when heated at moderate temperatures. The hidden entry system is especially useful for contests and promotional forms. Quickly striking the chromogenic composition with a fingernail or blunt object converts the latent image to a visible colored image by frictional heat. The chromogenic composition contains a chromogenic compound and a color developer which are non-pressure sensitive and non-reactive at room temperature. The latent image can be provided by an intimate mixture of the chromogenic compound and the developer or alternatively, one component can be printed on a separate layer or coating of the other component.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: September 6, 1994
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Peter A. Walter
  • Patent number: 4846502
    Abstract: A tamper evident document comprising a support bearing an autogenous coating including chromogenic material isolated from an electron-acceptor color developer material in which the autogenous coating bears a principal image comprising visible indicia of a transfer medium imprinted on the surface of the localized autogenous coating. Tampering with the principal image causes chromogen to react with the electron-acceptor color developer material to provide a color indication of tampering.
    Type: Grant
    Filed: June 24, 1986
    Date of Patent: July 11, 1989
    Assignee: Wallace Computer Services, Inc.
    Inventors: John C. H. Chang, Theodore Dimitriou