Rita Shao Shon

US Patent:

52100642, May 11, 1993

Filed:

Nov 20, 1991

Appl. No.:

7/795102

Inventors:

Rita S. Shon Baker - Brookline MA
Larry C. Takiff - Arlington MA

Assignee:

Polaroid Corporation - Cambridge MA

International Classification:

B41M 530

US Classification:

503201

Abstract:

The addition, to a thermal imaging medium comprising a color-forming compound which undergoes a change of color upon heating above a color-forming temperature for a color-forming time, the color-forming compound being of the cyclic sulfonamide type described in U. S. Pat. Nos. 4,720,449 and 4,960,901, of a quinone or hydroquinone increases the sensitivity of the imaging medium and helps to prevent fading of images produced therefrom while the images are being projected.

US Patent:

57416303, Apr 21, 1998

Filed:

Apr 25, 1994

Appl. No.:

8/232757

Inventors:

John L. Marshall - Somerville MA
Rita S. Shon Baker - Brookline MA
Larry C. Takiff - Arlington MA
Stephen J. Telfer - Arlington MA
John C. Warner - Norwood MA

Assignee:

Polaroid Corporation - Cambridge MA

International Classification:

G03C 173

US Classification:

430337

Abstract:

A process for producing and fixing an image uses an imaging medium comprising an acid-generating layer or phase comprising a mixture of a superacid precursor, a sensitizer and a secondary acid generator, and a color-change layer comprising an image dye. The sensitizer can absorb radiation of a sensitizer wavelength which does not, in the absence of the sensitizer, cause decomposition of the superacid precursor to form the corresponding superacid. The secondary acid generator is capable of acid-catalyzed thermal decomposition by the first acid to form a second acid, and the image dye undergoes a color change upon contact with the second acid. The medium is imagewise exposed to radiation of the sensitizer wavelength, thereby causing the sensitizer, in exposed areas, to decompose superacid precursor with formation of the fist acid. The medium is then heated to cause, in the exposed areas, acid-catalyzed thermal decomposition of the secondary acid generator and formation of the second acid. The components of the acid-generating and color-change layers or phases are mixed so that in exposed areas, the second acid causes the image dye to change color.

US Patent:

52062082, Apr 27, 1993

Filed:

Nov 20, 1991

Appl. No.:

7/795101

Inventors:

Rong C. Liang - Lexington MA
William C. Schwarzel - Billerica MA
Rita S. Shon Baker - Brookline MA
Robert P. Short - Arlington MA
Stephen R. Sofen - Lexington MA
Michael A. Young - Natick MA

Assignee:

Polaroid Corporation - Cambridge MA

International Classification:

B41M 530

US Classification:

503201

Abstract:

The addition, to a thermal imaging medium comprising a color-forming compound which undergoes a change of color upon heating above a color-forming temperature for a color-forming time, the color-forming compound being of the cyclic sulfonamide type described in U. S. Pat. Nos. 4,720,449 and 4,960,901, of a source of zinc, nickel, copper(II), cobalt(II) or aluminum(III) cations increases the sensitivity of the imaging medium and helps to prevent fading of images produced therefrom while the images are being projected.