Rong Jin Liang

US Patent:

62585053, Jul 10, 2001

Filed:

Mar 2, 2000

Appl. No.:

9/518045

Inventors:

Jayprakash C. Bhatt - Waltham MA
Daoshen Bi - Burlington MA
F. Richard Cottrell - South Easton MA
Rong C. Liang - Newton MA
William C. Schwarzel - Billerica MA
Tung F. Yeh - Waltham MA

Assignee:

Polaroid Corporation - Cambridge MA

International Classification:

G03F 7021

US Classification:

430157

Abstract:

An imaging medium comprises a substrate carrying a color-change layer. This color-change layer comprises two layers or phases comprising two color-forming reagents which react upon heating to cause a change in the color of the layer. The color-change layer is deactivated by exposure to actinic radiation such that after deactivation it no longer undergoes its thermal color-change. The color-change layer is detachable from the substrate by heating to a temperature lower than required to cause the color change, so that upon contact of the imaging medium with a receiving sheet each individual pixel of the color-change layer may be left attached to the substrate, transferred to the receiving sheet but left uncolored, or transferred to the receiving sheet and colored to a color level determined by the energy used in the associated thermal print head element. The medium may be imaged by imagewise heating, followed by blanket exposure to deactivating actinic radiation, or by imagewise exposure to the actinic radiation, followed by heating of the whole color-change layer.

US Patent:

60542462, Apr 25, 2000

Filed:

Jul 1, 1998

Appl. No.:

9/108624

Inventors:

Jayprakash C. Bhatt - Waltham MA
Daoshen Bi - Burlington MA
F. Richard Cottrell - South Easton MA
Rong C. Liang - Newton MA
William C. Schwarzel - Billerica MA
Tung F. Yeh - Waltham MA

Assignee:

Polaroid Corporation - Cambridge MA

International Classification:

G03C 518

US Classification:

430151

Abstract:

An imaging medium comprises a substrate carrying a color-change layer. This color-change layer comprises two layers or phases comprising two color-forming reagents which react upon heating to cause a change in the color of the layer. The color-change layer is deactivated by exposure to actinic radiation such that after deactivation it no longer undergoes its thermal color-change. The color-change layer is detachable from the substrate by heating to a temperature lower than required to cause the color change, so that upon contact of the imaging medium with a receiving sheet each individual pixel of the color-change layer may be left attached to the substrate, transferred to the receiving sheet but left uncolored, or transferred to the receiving sheet and colored to a color level determined by the energy used in the associated thermal print head element. The medium may be imaged by imagewise heating, followed by blanket exposure to deactivating actinic radiation, or by imagewise exposure to the actinic radiation, followed by heating of the whole color-change layer.

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.