Eastman-kodak Company

Lawrence E Contois

Norman G Rule

Yee S Ng

William Mey

George A Reynolds

Martin A Berwick

John D Mitchell

James D Walling

Rodney Ray Bucks

William J Staudenmayer

Eric Karl Zeise

Joseph Y Kaukeinen

Dennis R Kamp

James A Van Allan

Joseph H Ambro

Thomas M Plutchak

Albert V Buettner

Jean E Jones

Charles J Fox

Stephen Michel

Richard W Stahr

A photoelectrographic element for electrostatic imaging, containing a conductive layer and a photosensitive layer, is produced using photosensitive layer materials which form a barrier to charge injection where exposed to ultraviolet radiation. As a result, exposed areas can be charged, while unexposed portions cannot. The photosensitive layer contains an organic photoconductor, an ultraviolet radiation sensitizer, and, optionally, an organic binder. A method of forming images with this photoelectrographic element is also disclosed.

Photoelectrographic method for printing

A photoelectrographic element for electrostatic imaging, containing a conductive layer and a photosensitive layer, is produced using photosensitive layer materials which form a barrier to charge injection where exposed to near-infrared radiation. As a result, exposed areas can be charged, while unexposed portions cannot. The photosensitive layer contains an organic photoconductor, a near-infrared radiation sensitizer, and, optionally, an organic binder. A method of forming images with this phctoelectrographic element is also disclosed.

Near-infrared radiation sensitive photoelectrographic master and imaging

Techniques are provided for regenerating photoconductor elements, particularly those of the unipolar, homogeneous type. These techniques utilize a low-voltage to moderate-voltage reverse charge. Also provided are new photoconductor elements useful in the practice of such techniques.

Photoconductor element, regenerating methods and elements useful therein

An LED printhead includes an optical mask overlying the LED's to balance light outputs therefrom. The transmission density of the mask is adjusted for each LED in accordance with its respective light output to adjust same so that the light outputs from all LED's are the same. The mask comprises a UV fadeable dye whose transmission density is adjusted with a UV laser or other light source while monitoring the light output from the respective LED. The transmission density of the mask may be adjusted by a UV light source provided on the printhead during periods of nonuse of the printhead or the printhead may be removed from the recording apparatus for adjustment.

Non-impact printhead using a mask with a dye sensitive to and adjusted

An electrophotographic imaging method is described that uses an element comprising a photoconductive layer on an electrically conducting substrate capable of transmitting actinic radiation to which the photoconductive layer is responsive, and a dielectric support, releasably adhered to the substrate, comprising the photoconductive layer or an overcoat thereof forming a surface of the element capable of holding an applied electrostatic charge. To use the element, the surface of the dielectric support is charged, and the photoconductive layer is imagewise-exposed to actinic radiation, thereby forming a developable electrostatic image on the dielectric surface. The electrostatic image, in turn, is developed with toner to form a first color image. A composite color image is formed on the element by repeating the sequence one or more times with imagewise exposure of the photoconductive layer to actinic radiation transmitted through the substrate, and developing over each preceding image with a different color toner. The composite toner image is transferred with the dielectric support to a receiving element to form a color copy such as a three-color filter array or a color proof closely simulating the color print expected from a full press run.

Electrophotographic color imaging method

Electrophotographic color proofs of half-tone dot pattern images are made which closely simulate the dot gain of prints made with lithographic plates and liquid inks. In forming the color proof, a thin transparent plastic sheet having on one side an electrophotographic toner dot pattern image is laminated to a reflective support with the toner image side in contact with the support. A thicker transparent plastic sheet is laminated to the other side of the thin sheet. The resulting color proof comprising a toner dot pattern on a reflective support and covered by a thin transparent layer and a thicker transparent layer has an apparent increase in dot size which simulates that of a press print.

Color proofing method and article

An electrophotographic proofing element is described comprising a photoconductive layer on an electrically conducting substrate, capable of transmitting actinic radiation to which the photoconductive layer is responsive, and a dielectric support, releasably adhered to the substrate, comprising the photoconductive layer or an overcoat thereof forming a surface of the element capable of holding an applied electrostatic charge. To use the element, the surface of the dielectric support is charged, and the photoconductive layer is imagewise-exposed to actinic radiation, thereby forming a developable electrostatic image on the dielectric surface. The electrostatic image, in turn, is developed with toner to form a first color image. A composite color image is formed on the element by repeating the sequence one or more times with imagewise exposure of the photoconductive layer to actinic radiation transmitted through the transparent support, and developing over each preceding image with a different color toner. The composite toner image is transferred with the dielectric support to a receiving element to form a color copy such as a three-color filter array or a color proof closely simulating the color print expected from a full press run.

Electrophotographic color proofing element and method for using the same

Photoconductive compositions and elements comprising arylalkane photoconductors and pyrylium sensitizers are stabilized against adverse leuco base color shifts into the ultraviolet to blue spectral region by the incorporation of certain 1,4,5,8-naphthalene bis-dicarboximide compounds. The compositions and elements are particularly suited for electrophotographic image formation and thereafter for contact printing of the image onto sensitive material by ultraviolet or blue transmission through the composition or element.

Pyrylium-sensitized leuco base photoconductive compositions and elements

Protonic acid-free photoconductive compositions and elements comprising a photoconductor and, as a sensitizer, a 4-tertiaryaminobenzo�b!pyrylium salt or a 4-tertiaryaminobenzo�b!thiopyrylium salt. The resulting compositions and elements exhibit low persistent conductivity.

Pyrylium- and thiopyrylium-sensitized low-persistence photoconductive

A plurality of aggregate photoconductive particles having a predominant particle size of less than about 1.0 micron are disclosed. Such particles are useful in heterogeneous photoconductive compositions, electrophotographic elements and electrophotographic imaging processes.

High resolution heterogeneous photoconductive compositions and method of

Photoconductive layers containing a crystallization inhibiting mixture of at least two different organic photoconductors selected from the class of photoconductors represented by the following formula ##STR1## wherein R is selected from the group consisting of alkyl, aralkyl, and substituted and unsubstituted aryl;

Crystallization inhibiting mixtures of arylmethane photoconductors

Electrostatic contrast control in p-type electrophotographic elements is achieved by incorporating into the photoconductive layer a hole trapping agent such as a tetraphenylboron anion, bromide ion, iodide ion, oxidizable dye such as a carbocyanine and dicarbocyanine, merocarbocyanine and merodicarbocyanine, styryl, oxonol, hemioxonol, or hemicyanine. Usable hole trapping agents have an oxidation potential in a neutral solution of at least 0.1 volts less than that of the photoconductor in the photoconductive layer.

Additives for contrast control in organic photoconductor compositions

An organic photoconductive insulating composition and electrophotographic elements containing the same are prepared using as a photoconductor a polyarylalkane compound having the formula ##STR1## wherein R.sup.1 and R.sup.2 represent hydrogen, alkyl, or aryl groups, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 represent aryl groups, and A.sup.1 and A.sup.2 represent phenyl groups.

Photoconductive compositions and elements

Coloration resistant photoconductive insulating compositions useful in making elements, such as photoconductive electrophotographic papers, are provided. Such compositions comprise (1) an electrically insulating organic binder, (2) a nitrogen-free polyaryl hydrocarbon photoconductor such as those having the formula ##STR1## wherein: N REPRESENTS AN INTEGER HAVING A VALUE OF 0, 1 OR 2,

Low color photoconductive insulating compositions comprising

A specific class of crystalline organic pigments having the formula ##STR1## WHEREIN N IS 1 OR 2; X consists of the atoms necessary to complete a naphthalene, anthracene, or ##STR2## R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, halogen, alkoxy, NO.sub.2, alkyl, SO.sub.3 H or alkali metal salts thereof, and COOH or alkali metal salts thereof; and wherein R.sup.2 and R.sup.3 can comprise the atoms necessary to complete a phenyl, naphthyl or anthryl ring; and R is selected from the group consisting of ##STR3## or COOM wherein M is alkyl or an alkali or alkaline earth metal is useful as sensitizers for photoconductive compositions in electrophotographic processes.

Growing community of inventors

Webster, NY, United States of America

Lawrence E Contois