American Hoechst Corporation

Hoechst Celanese Corporation

Bayer Corporation

Agfa Gevaert Nv

Douglas A Seeley

Major S Dhillon

Shane Hsieh

Raimund J Faust

Shuchen Liu

William Jeffers

David M Sullivan, Deceased

George L Malinoski, Jr

Andreas Elsaesser

Gabor I Koletar

Victor M Kamhi

Mathias Eichhorn

Otfried Gaschler

Fritz-Feo Grabley

Thomas Leichsenring

Helmut Haberhauer

Sonya Y Shaw

Judith Ann Sullivan

A positive-working or negative-working radiation-sensitive mixture includes as an IR absorbing component a carbon black pigment having a primary particle size smaller than 80 nm. The carbon black pigment is predispersed in a polymer containing acidic units having a pK.sub.a of less than 13. The radiation-sensitive component may include an ester of (i) a 1,2-naphthoquinone-2-diazide-4-sulfonic acid or a 1,2-naphthoquinone-2-diazide-5-sulfonic acid and (ii) a compound having at least one phenolic hydroxyl group, such as 3 to 6 phenolic hydroxyl groups. After imagewise radiation exposure, the recording material including the radiation-sensitive mixture can be developed without difficulties in an aqueous alkaline solution without leaving residual coating on the areas that became soluble or that remained soluble upon exposure.

Radiation-sensitive mixture and recording material made thereof for

This invention pertains to an ultrafiltration process which maintains a constant developer strength in a printing plate developing operation. Such a process enables development of more plates than conventional processes while using less developer and generating less liquid waste. The ultrafiltration process is suitable for both batch and continuous plate development operations. By this process, used developer is filtered and the fluid portion returned to the working developer solution. The filtered out remainder mass is treated with an absorber to convert it into a solid.

Process for rejuvenating developer in printing plate development

This invention discloses a novel process to maintain constant developer strength in a printing plate manufacturing operation. Such a process enables development of more plates than conventional processes allow, while at the same time using less quantity of developer and generating fewer liquid waste. The process is suitable for both batch type and continuous plate development operations. The invention also describes an apparatus suitable for the above-described process.

Apparatus for rejuvenating developer in printing plate development

A process for producing a color image on color proofing film which comprises:

Method of thermal wax transfer as a mask for digital color proofing

A developing and finishing composition for lithographic printing plates containing:

Developer-finisher compositions for lithographic plates

Method of using developer-finisher compositions for lithographic plates

This invention relates to an improvement in a photochemical process for the preparation of printing plates wherein a printing plate comprising a photosensitive composition coated on a support is exposed to a pattern of laser light, the intensity of which is modulated in accordance with an input source of information and said printing plate is subsequently developed by removal from said support of that portion of the photosensitive coating composition which is not exposed to said pattern of laser light, the improvement comprising utilizing a pattern of laser light generated by a laser at a wavelength greater than about 450 nm, and utilizing as a photosensitive composition a negative-working condensate of a para-aminobenzene diazonium compound, said compound being present in a quality of at least 25% of the total coating weight.

Dialo printing plate made from laser

Provided is a laser beam optical scanner apparatus as a component in a system for the scanning of an original and the simultaneous exposure of a light sensitive surface of a printing master with the image of the original for the production of a printing plate. Said apparatus comprises rotating reflective means having at least one planar reflective segment. Said segment defines a tilt angle which is off normal to the axis of rotation of said rotative, reflective means. The system further comprises means for rotating said reflective means about its axis of rotation; means for supporting said reflective means at a position interposed in the common path of a read and write laser beam for deflecting said laser beam into a roof mirror arrangement and for receiving the same beam reflected out of said roof mirror arrangement, to scan a line at an output plane in space. Said roof mirror arrangement includes a first mirror with a first planar reflective surface and a second mirror with a second planar reflective surface. Said first and second mirrors are disposed in fixed positions relative to each other and to the rotating reflective means. Said laser beams are reflected 2n times between said first and said second mirrors and 4n times in said rotating reflective means before the laser beams emerge the optical scanner apparatus, where n is any integer.

Light beam scanning apparatus

A process for preparing a lithoplate by electrophotographic means is provided wherein the toned image is fused, the photoconductive layer in the nonimage area is decoated, and finally, the fused toner is selectively removed leaving oleophilic photoconductive material as the image portion.

Method of preparing lithoplates and plate

This invention relates to an improvement in a photochemical process for the preparation of printing plates wherein a printing plate comprising a photosensitive composition coated on a support is exposed to a pattern of laser light, the intensity of which light is modulated in accordance with an input source of information, and said printing plate is subsequently developed by removal from said support of that portion of the photosensitive coating composition which is not exposed to said pattern of laser light, the improvement comprising utilizing a pattern of laser light generated by a laser, and utilizing as a photosensitive composition a mixture consisting essentially of: (1) a negative-working condensate of a para-amino benzene diazonium compound present in an effective amount sufficient to sensitize said photosensitive composition to laser light, and (2) a colorant capable of absorbing light in the spectral range between about 450 -550 nm, said colorant selectively sensitizing the condensate to said laser light at a wavelength greater than about 450 nm, and being selected from the group consisting of azo, triarylmethane, xanthene and methine compounds.

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High Bridge, NJ, United States of America

Douglas A Seeley