Patents by Inventor Siu-Chung Tsoi

Siu-Chung Tsoi 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: 6083673
    Abstract: The present invention concerns an organic/inorganic developer composition comprising a regeneratable iron chelate, novel codevelopers of the phenidone type including one or more solubilizing groups that are not directly attached to the phenyl nucleus or to the pyrazolidino nucleus and optionally ascorbic acid. These compositions are particularly useful for the black-and-white development of films or photographic papers, in particular for the fast development of radiographic products.
    Type: Grant
    Filed: March 31, 1998
    Date of Patent: July 4, 2000
    Assignee: Eastman Kodak Company
    Inventors: Jacques Roussilhe, Siu Chung Tsoi
  • Patent number: 5958664
    Abstract: The present invention relates to a new coupler which is capable of releasing a development accelerator having the formula: ##STR1## wherein COUP is a coupler moiety,T is a timing group and n is 0, 1 or 2,A is a group capable of being adsorbed to the silver halide surface,L is a linking group and r is 0 or 1, andR.sub.1 and R.sub.2 are independently selected from an alkyl group, substituted or unsubstituted, and an aryl group, substituted or unsubstituted.The present invention also concerns a photographic silver halide recording material containing such a coupler and further relates to a process for processing such a material.The invention provides a new DARC compound showing improved speed increase without undue fog formation.
    Type: Grant
    Filed: July 30, 1998
    Date of Patent: September 28, 1999
    Assignee: Eastman Kodak Company
    Inventors: Siu-Chung Tsoi, Peter J. Twist, David T. Southby
  • Patent number: 5837434
    Abstract: The invention concerns a developer solution for processing silver halide photographic products. This developer solution contains an ascorbic acid developing agent, a auxiliary developing agent which is a substituted phenidone and a development accelerator which is a thioether having an ammonium group, a triazolium thiolate or a substituted thioalkane.
    Type: Grant
    Filed: September 25, 1997
    Date of Patent: November 17, 1998
    Assignee: Eastman Kodak Company
    Inventors: Jacques Roussilhe, Siu-Chung Tsoi