Abstract: A fountain concentrate for preparing a dampening or fountain solution for lithography, consisting essentially of a mixture of a desensitizer, sulfanilic acid, and formaldehyde.

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 disposable sheet to replace the rubber blanket of an offset printing machine basically consists of a flexible carrier sheet and a coating on one face of the sheet consisting essentially of a cellular latex of a synthetic elastomer free from inorganic fillers in more than incidental trace amounts and deriving its capability of receiving an inked image from partial cross linking.

Abstract: This invention relates to a printing plate comprising a support bearing either(A) a layer comprising particles each containing a hydrophilic metal core and an oleophilic metal casing or(B) a layer comprising particles each containing an oleophilic metal core and a hydrophilic metal casing.

Abstract: A protective coating material for lithographic printing plate, which comprises pullulan or pullulan derivatives. Said material is superior to hitherto used gum arabic solution in the protection of the surface of lithographic printing plate against oxidation and scumming as well as in the ability to enhance the hydrophilic character of metallic surface of a non-image area.

Abstract: A process for preparing a waterless printing master having a minimum background ink reflection density comprises coating a master substrate with an ink releasing block copolymer comprising elastomeric ink releasing siloxane blocks and isothermally crystallizable thermoplastic organic blocks. Thereafter, the thermoplastic blocks are isothermally crystallized and the siloxane blocks are preferably cross-linked. The printing master is imaged by depositing ink accepting particulate imaging material on the copolymer coating and heating and cooling the thermoplastic blocks to bond the particulate imaging material thereto.

Abstract: A novel method for preparing a stencil master, a novel stencil and a method for printing therefrom are provided. The method for preparing the stencil comprises coating a suitable screen with a curable silicone containing a curing catalyst, depositing a particulate image pattern on said coated screen with a material which selectively inactivates said curing catalyst below said image pattern, curing the resultant nonimaged silicone to an elastomeric ink releasable condition and removing the particles from said particulate image pattern and the uncured silicone below said pattern to provide perforations in imagewise configuration. The method for printing comprises the additional steps of contacting the resultant screen with an image receiving member and passing ink through said perforations to thereby form an inked image on said receiving member.

Abstract: A lithographic printing plate which comprises using in an ink-repellent layer a polymer of a monomer or a copolymer containing said monomer, said monomer being represented by the following general formulas: ##STR1## WHEREIN: R is hydrogen or a methyl radical; R' is hydrogen or an alkyl radical having 1 to 10 carbon atoms; Rf is a perfluoroalkyl radical having 3 to 21 carbon atoms; and n is an integer of 1 to 10.

Abstract: A process for producing a locally desensitized color developer sheet which comprises using a desensitizer composition having a contact angle of not less than 15.degree. with hydrophobic non-image areas of a lithographic pringing plate and having a wetting action with the hydrophilic image areas of said plate. Using a hydrophilic image lithographic plate to selectively desensitize a color developer sheet using the desensitizer composition.

Abstract: A planographic printing master comprising an ink releasing photoconductive insulating layer and an ink receptive particulate image pattern.

Abstract: A method of producing a lithographic printing master, novel masters and a method of printing therefrom are provided which obviate the need for an aqueous fountain solution. The process for printing comprises applying an ink and a solvent (which may or may not be in the ink) to an imaged master and transferring the resultant developed image to a receiver member. The nonimaged portions of said master are formed of an ink releasing solvent swellable elastomer selected from organohydrocarbon backbone polymers (which may or may not contain hetero atoms), copolymers and mixtures. The solvent is a fluid capable of swelling the nonimaged areas of said elastomer but not capable of dissolving the elastomeric imaged master. The solvent is added in an amount to diffuse into the nonimaged areas of the imaged master and form a substantially ink-free layer on the nonimaged areas of the master during inking and transferring of the inked image.

Abstract: Improved waterless lithographic printing masters are provided having minimum background ink reflection density. The master comprises a crosslinked block copolymer containing elastomeric, ink releasing siloxane blocks chemically linked to organic image accepting thermoplastic blocks, said copolymer having a molecular weight for the organic blocks sufficient to provide strength and a background ink reflection density of less than 0.02 and preferably less than 0.01.

Abstract: Aluminum based lithographic printing plates are treated with triethanolamine titanate and heat to impart added solvent resistance and strength to non-crosslinked ink-receptive image areas, thereby affording an increase in press life.

Abstract: Electrostatic printing is conducted by using an electrostatic printing master composed of an insulating medium having an electric resistance sufficient to retain an electrostatic charge and conductive silver images carried in the insulating medium and heating the electrostatic printing master.

Abstract: A conversion solution for rendering hydrophilic the zinc oxide resin binder type planographic masters containing 2.0% potassium ferrocyanide, phosphoric acid to produce a pH in the range of 4.1 - 4.2 and a buffering salt of ammonium acid phosphate or sodium acid phosphate to buffer the solution and 4.0% by weight of triethanolamine as a modifying and solvating agent to raise the solubility threshold preventing formation of needle-like crystals that tend to form as water evaporates from the solution, and modify the physical property of crystals that do form to a less-hard structure.

Abstract: A lithographic duplicating machine includes a device for feeding an imaged master from a stack of masters through a treating unit, containing conversion fluid for converting the imaged surface of the master, to a master cylinder. A motor drive system is provided for conditioning the master cylinder for operation at a printing speed and a starting speed for drawing the master through the treating unit. The motor speed is controlled by an electronic switching arrangement which receives input signals from machine responsive electrical switches and manually settable potentiometers to which the motor drive system is connected.

Abstract: A universal fountain solution formulation for lithographic printing is disclosed that is particularly useful in Dahlgren-type plate dampening systems. The fountain solution is prepared from two etch concentrates, the first (solution A) having as its primary ingredients a fatty acid material, a monovalent hydroxide and water, and the second (solution B) having as its primary ingredients gum arabic a monovalent iodide and water. Different amounts of the primary ingredients are mixed together to form the etch concentrates which are subsequently mixed together with water to produce the final fountain solution formulations.

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: A solution for treating metal surfaces is provided which is capable of cleaning (degreasing) and hydrophilically sensitizing the metal surface. The treatment solution is a synergistic improvement over conventional silicate treating solutions obtained by the addition of the ferric chelate of ethylene diamine tetra acetic acid (Fe.sup.+.sup.3 EDTA).

Abstract: The planographic printing plate has ink-receptive and ink-repellent areas provided on its base, the ink-repellent areas being covered with a layer formed by polymerizing and curing a composition which comprise a photopolymerizable organopolysiloxane with maleimido groups. The photopolymerizable organopolysiloxane has easily synthesized. The ink-repellency of the cured organopolysiloxane is excellent. The planographic printing plates can be used without dampening water and have a superior press life.

Abstract: Prior to conversion of an offset master imaged by electrostatic technique to render the non-imaged portions of the imaged master ink repellent and water receptive, the surface is pre-wet with an organic solvent system which leaves residual solvent on the surface at the time of conversion.

Abstract: A method of removing irregularities on the surface of a waterless lithographic master comprising selectively heating an imaged adhesive silicone master, which is deformable at elevated temperature, at a temperature and for a time sufficient to smooth out irregularities in the surface of the master.

Abstract: A method of providing a printing plate comprises coating on a support a layer having a hydrophilic surface comprising the homogeneous reaction product of hydrolyzed polyvinyl acetate and hydrolyzed tetraethyl orthosilicate. The coating may also contain pigments such as titanium dioxide and the like. A printing plate is provided having a support having thereon a layer having a hydrophilic surface and over the layer a silver precipitating layer, preferably comprising nickel sulfide and silver iodide. An image is provided in the silver precipitating layer by diffusion transfer and treated with a thiol or similar sulfur-containing material to improve the ink-water balance of the plate.

Abstract: A method of forming a hydrophobic surface is disclosed. The method comprises coating a substrate surface with a stable aqueous colloidal solution, formed by a controlled hydrolysis and nucleation reaction, comprising insoluble hydrous oxide particles of an element selected from Be, In, Cr, Fe, Co, Ni, Tl, Cu, Zn, Sn and mixtures thereof. The coated surface is then exposed to a source of ultraviolet radiation having a wavelength ranging from 1800A to 3300A to render exposed surface regions hydrophobic.

Abstract: A coherent silver image which is bonded to the grained surface of an aluminum lithographic plate having an aluminum oxide layer thereon is transformed into a hydrophilic non-image area by contacting the silver image with a viscous composition comprising an aqueous nitric acid solution of sufficient concentration to rapidly effect the removal of the silver image and thereby expose the aluminum oxide under this image and wherein the viscous composition has a viscosity of at least about 500 centipoises. The preferred viscous composition is a thixotropic composition consisting essentially of (1) an aqueous solution of nitric acid present in an amount between about 35% and 70% by volume based upon the total volume of nitric acid solution, and (2) finely divided inert metal oxide capable of imparting thixotropic properties to the solution.

Abstract: A presensitized lithoprinting plate which needs no fountain solution on printing comprising a support and a coating layer of a mixture of a photosensitive material and a silicone rubber.

Abstract: A dry presensitized planographic plate composed of a support having coated thereon one or two layers of (a) a silicone rubber, (b) a photosensitive azide compound, (c) a cyclized rubber, and (d) a copolymer of vinylidene chloride and acrylonitrile, the uppermost layer, when the planographic plate has two layers, containing at least the component (a) and (b) and the lower layer containing at least the component (c).