Abstract: Provided is a process for preparing an improved gum formulation useful for preventing oxidation in exposed and developed lithographic printing plates. The gum so produced exhibits reduced foaming and air entrapment properties.

Abstract: A positive working radiation sensitive plate is image-wise exposed, developed and desensitized, and dried. Thereafter an oleophilic composition including a solvent capable of softening the image is applied to the plate and the plate is then washed to remove the oleophilic composition from the non-image areas. The image accepts ink readily even when the image-wise exposure is effected using a continuous tone original in the absence of a half-tone screen.

Abstract: A conversion solution for zinc oxide coated electrophotographic master printing plates is provided containing triethylenetetramine or ethylenediamine which replaces the normally used ferrocyanide in conventional EP master conversions solutions.

Abstract: A method and apparatus for adding ink receptive areas to or removing ink receptive areas from printing plates in which a consumable stylus, such as a graphite pencil "lead," or a non-consumable stylus, such as a copper wire, is brought into contact with the printing plate.

Abstract: A developer composition for photosensitive coatings on substrates, particularly lithographic printing plates sensitized with substantially water-insoluble diazonium compounds, which is comprised of an aqueous solution of a substantially water-soluble organo-lithium salt, e.g., lithium naphthenate, lithium benzoate, lithium ricinoleate, etc. The novel developers quickly remove unexposed areas of the plate and yet do not detrimentally dissolve the exposed areas of the plate.

Abstract: A composition for improving the ink receptivity of lithographic printing images comprises an organic solvent liquid capable of softening the surface of the printing image and a film forming alkali-resistant oleophilic material such as a liquid hydrocarbon solution of a normally solid hydrocarbon or fat. The composition is for use in the case where the printing image is formed by alkaline development of an image-wise exposed radiation sensitive coating such as a phenol formaldehyde resin in admixture with a sensitiser. The composition may be applied before exposure to form an alkali resistant oleophilic layer on the radiation sensitive coating or it may be applied after image-wise exposure but before alkali development.

Abstract: A display and printing method using an electrochromic imaging material. The electrochromic material forms a colored image in response to the formation of an image pattern on a photoconductive surface. The electrochromic material is between an electrode and the photoconductive surface when image formation takes place. The image may be utilized in a display device or in printing.

Abstract: A method for the preparation of a planographic printing plate wherein a sheet material comprising an outer hardenable hydrophilic colloid layer on whose surface is concentrated a visible silver image that has been formed thereon from silver halide complexes according to the silver complex diffusion transfer process, is treated with an aqueous lithographic fixer having a pH in the range of 1.0 to 6.5 and containing1. an iron(III) salt of a polyaminopolycarboxylic acid as oxidizing agent for the silver image,2. a compound yielding in dissolved state iodide ions as precipitating agent for silver ions, and3. an organic onium compound.

Abstract: A gum removing solution for a lithographic plate containing at least one compound selected from the group consisting of compounds containing ##STR1## linkage where M represents a hydrogen atom, an ammonium group or an alkali metal atom and cyclic esters and cyclic amides having 3 to 6 carbon atoms. The solution can further contain at least one compound selected from the group consisting of phosphoric acid and polyphosphoric acid and the metal salts and ammonium salts of these acids, and optionally a water-soluble colloid. The solution has a pH of 1 to 5.5.

Abstract: A novel printing master and method for producing the same as disclosed, which comprises coating a suitable substrate with an uncured silicone gum, followed by the adherence thereto of a particulate image pattern. Resultant curing of the gum converts the gum to a tough elastomeric ink releasable film, thereby fixing the integral particles to the film while in intimate contact therewith. After curing, substantially all of the deposited particles are removed from the elastomer film, thereby revealing a "porous" image in the ink releasable film, of surprising ink receptive characteristics. The porous image thus is formed by contact of the integral particles of varying geometric shapes and sizes with the uncured silicone gum, thereby creating "impressions" of the particles in the gum which are then permanently stabilized in the gum by curing of the gum to an elastomeric film.

Abstract: Improved waterless lithographic plates are provided. The master which comprises a copolymer of siloxane blocks crosslinked to an elastomeric ink releasing condition and organic thermoplastic blocks which are ink accepting is imaged with a particulate material, preferably an ink accepting thermoplastic polymer, and the thermoplastic blocks heated and cooled to bond the particulate imaging material thereto.

Abstract: Novel means for preparing waterless lithographic printing masters by ink jet imaging means are provided. A master is provided by depositing a silicone or other material which can be rendered ink releasing on a suitable master substrate by means of an ink jet printing apparatus, and curing the silicone to an elastomeric ink releasing condition. Alternatively, an ink jet printing apparatus can be employed to deposit in image configuration, a catalyst to an uncured silicone on a master substrate, a photopolymer to a cured silicone on a master substrate which photopolymer can be cured to combine with the silicone, or an imaging light insensitive shadow fluid to a light sensitive curable silicone coated on a master substrate whereby the background nonimaged areas can be cured and the shadow fluid and underlying silicone removed to reveal the ink accepting substrate.

Abstract: A method for the preparation of a planographic printing plate wherein a photoexposed and developed photographic material containing a pattern of poorly water-soluble silver salt is treated with an aqueous liquid which contains in dissolved state an organic cationic compound or mixture of organic cationic compounds, iodide ions, and a sufficient amount of hydronium ions (H.sub.3 O.sup.+) for creating an acidic medium, said liquid being capable of making an unexposed and undeveloped photographic silver halide material as defined in the disclosure sufficiently receptive for a lithographic ink.

Abstract: Continuous tone images are reproduced on a plate having metallic images adherently and preferably conductively bonded to a physically roughened support by contacting with a photographic physical developer an imaging medium comprising a physically developable image of the continuous tone image. The process has the capability of producing an imaged plate containing metal images of varying contrast and varying tonal range and then using the imaged plate as a printing plate. A preferred copy medium comprises a thin silver halide layer coated on a grained and anodized aluminum support.

Abstract: A process is provided for forming waterless lithography printing masters comprising depositing a particulate image pattern on a non-tacky rubbery uncured silicone polymer, converting the non-tacky polymer into a softened gummy state and curing said softened polymer to fix the toner thereto.

Abstract: A new dry planographic plate having a non-ink receptive silicone rubber background area that does not require a fountain solution to repel printing ink and process of producing this new plate comprising applying the photoresponsive sensitizer to a polymeric support film and bringing the sensitizer layer into intimate adhesive contact with an uncured silicone gum and thereafter curing the silicone gum.

Abstract: In a lithographic printing plate comprising a base and a lithographic printing surface thereon, said printing surface comprising colloidal silica and an insolubilized hydrophilic polymer, the improvement which comprises providing a positively charged colloidal silica as said colloidal silica component and, as said hydrophilic polymer, a nonionic or cationic polymer or a mixture of the same.