Patents by Inventor Philip J. Watkiss

Philip J. Watkiss 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).

  • Improvements in or relating to printing plates
    Patent number: 5609987
    Abstract: A hydrophobic synthetic resin is used to partially or completely replace the hydrophilic colloid conventionally used in silver halide emulsions to obtain a radiation sensitive composition useful in the manufacture of radiation sensitive plates for use in printing plate production by image-wise exposure, tanning development, and washing. The synthetic resin includes a plurality of primary amino groups and optionally acidic groups and is soluble in aqueous or semi-aqueous alkaline solution.
    Type: Grant
    Filed: August 9, 1995
    Date of Patent: March 11, 1997
    Assignee: Du Pont (U.K.) Limited
    Inventors: John M. Kitteridge, Andrew E. Matthews, Philip J. Watkiss
  • Recovery of silver
    Patent number: 5118344
    Abstract: In a method of recovering silver from an aqueous suspension, the suspension is admixed with a solution capable of converting silver halide to metallic silver to cause flocculation of the silver, the flocculated silver is separated from the aqueous phase, and the silver is recovered.
    Type: Grant
    Filed: October 19, 1989
    Date of Patent: June 2, 1992
    Assignee: E. I. Du Pont de Nemours and Company (Inc.)
    Inventor: Philip J. Watkiss
  • Printing plate precursors
    Patent number: 4859290
    Abstract: A lithographic printing plate precursor for use in a silver diffusion transfer system comprises a grained and anodized aluminum substrate having coated thereon a sol containing nuclei for precipitating silver from a silver complex. The substrate has an anodic weight (gm.multidot.m-.sup.2) to surface roughness (microns) ratio greater than or equal to 6. Printing plates produced from such precursors are less prone to corrosion and have improved printing life.
    Type: Grant
    Filed: February 9, 1988
    Date of Patent: August 22, 1989
    Assignee: Vickers plc
    Inventor: Philip J. Watkiss
  • Lithographic printing plates
    Patent number: 4567131
    Abstract: A lithographic printing plate having metallic silver image areas is treated with a proteolytic enzyme and an oleophilizing compound to improve ink receptivity.
    Type: Grant
    Filed: July 11, 1984
    Date of Patent: January 28, 1986
    Assignee: Vickers Plc
    Inventor: Philip J. Watkiss