Polaroid Corporation

Larry C Takiff

Stephen J Telfer

John L Marshall

Russell A Gaudiana

John C Warner

Michael A Young

Rita S Baker

Robert W Haddock

Kenneth C Waterman

Socorro M Ramos

Serajul Haque

Rita S Shon Baker

Anne Ehret

Iris B Kliman Bloom

A process for producing an image uses an imaging medium comprising an acid-generating layer or phase comprising a mixture of a superacid precursor, a sensitizing dye and a secondary acid generator, and a color-change layer comprising an image dye. The sensitizing dye has first and second forms, the first form having substantially greater substantial absorption in a first wavelength range than the second form. The superacid precursor is not capable, in the absence of the first form of the sensitizing dye, of being decomposed by radiation in the first wavelength range. The secondary acid generator is capable of thermal decomposition, catalyzed by superacid, to form a secondary acid. While at least part of the sensitizing dye is in its first form, the medium is imagewise exposed to radiation in the first wavelength range, thereby causing, in the exposed areas of the acid-generating layer, the formation of superacid. The medium is then heated to cause, in the exposed areas, thermal decomposition of the secondary acid generator, catalyzed by the superacid, and formation of the secondary acid. The components of the acid-generating and color-change layers or phases are then mixed so that the secondary acid causes a change in color of the image dye, and the sensitizing dye is converted to its second form. The acid-generating layer or phase desirably includes a cosensitizer which is a reducing agent less basic than the secondary acid generator.

Imaging medium and process for producing an image

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. At least the non-exposed areas, a copper compound and a reactive material more reactive than the image dye to the products resulting from decomposition of the superacid precursor in the presence of the copper compound, are used to decompose the superacid precursor and fix the image.

Process for fixing an image, and medium for use therein

A process for producing an image uses an imaging medium comprising an acid-generating layer or phase comprising a mixture of a superacid precursor, a sensitizing dye and a secondary acid generator, and a color-change layer comprising an image dye. The sensitizing dye has first and second forms, the first form having substantially greater substantial absorption in a first wavelength range than the second form. The superacid precursor is capable of being decomposed to produce superacid by radiation in a second wavelength range, but is not, in the absence of the sensitizing dye, capable of being decomposed by radiation in the first wavelength range. The secondary acid generator is capable of acid-catalyzed thermal decomposition by unbuffered superacid to form a secondary acid. While at least part of the sensitizing dye is in its first form, the medium is imagewise exposed to radiation in the first wavelength range, thereby causing, in the exposed areas of the acid-generating layer, the formation of unbuffered superacid. The medium is then heated to cause, in the exposed areas, acid-catalyzed thermal decomposition of the secondary acid generator and formation of the secondary acid. The components of the acid-generating and color-change layers or phases are then mixed so that the secondary acid causes a change in color of the image dye, and the sensitizing dye is converted to its second form. The acid-generating layer or phase desirably includes a cosensitizer which is a reducing agent less basic than the secondary acid generator.

Imaging medium

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 secondary acid, and the image dye undergoes a color change upon contact with the secondary 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 secondary acid. The components of the acid-generating and color-change layers or phases are mixed so that in exposed areas, the secondary acid causes the image dye to change color. At least the non-exposed areas, there is reacted with the superacid precursor a reactive material which irreversibly destroys the superacid precursor, thus fixing the image.

A process for producing an image uses an imaging medium comprising an acid-generating layer or phase comprising a mixture of a superacid precursor, a sensitizing dye and a secondary acid generator, and a color-change layer comprising an image dye. The sensitizing dye has a unprotonated form and a protonated form, the protonated form having substantially greater substantial absorption in a first wavelength range than the unprotonated form. The superacid precursor is capable of being decomposed to produce superacid by radiation in a second wavelength range, but is not, in the absence of the sensitizing dye, capable of being decomposed by radiation in the first wavelength range. The secondary acid generator is capable of acid-catalyzed thermal decomposition by unbuffered superacid to form a second acid. While at least part of the sensitizing dye is protonated, the medium is imagewise exposed to radiation in the first wavelength range, thereby causing, in the exposed areas of the acid-generating layer, the formation of unbuffered superacid. 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 then mixed so that the second acid causes a change in color of the image dye, and sufficient base is introduced into the unexposed areas to restore the sensitizing dye to its unprotonated form.

An infra-red sensitive acid-generating medium comprises a binder, an iodonium salt; and a squarylium dye capable of absorbing infra-red radiation having a wavelength within the range of about 700 to about 1200 nm, the dye having a squarylium ring the 1- and 3-positions of which are each connected, via a single sp.sup.2 carbon atom, to a pyrylium, thiopyrylium, benzpyrylium or benzthiopyrylium nucleus, at least one of the sp.sup.2 carbon atoms having a hydrogen atom attached thereto, and the 2-position of the squarylium ring bearing an O.sup.-, amino or substituted amino, or sulfonamido group.

Processes and compositions for photogeneration of acid

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.

Growing community of inventors

Arlington, MA, United States of America

Larry C Takiff