Abstract: A heat-sensitive lithographic printing plate precursor which comprises a substrate having thereon an anodic oxidation layer, with the printing plate precursor comprising a hydrophilic layer containing at least one kind of fine particles selected from the group consisting of heat-fusible hydrophobic thermoplastic fine particles, finely divided polymers having thermally reactive functional groups and microcapsules in which compounds having heat-reactive functional groups are encapsulated, and with the anodic oxidation layer having a surface over which micropores having an average pore size of 6 to 40 nm are uniformly distributed.

Abstract: A lithographic printing plate precursor comprises an electrochemically grained aluminium substrate, the grained surface of which is coated with a layer of gel-like amorphous colloidal oxides and hydroxides of aluminium and their hydrates incorporating metallic aluminium and inter-metallic aluminium alloys—generally at a level of below 5%—this layer being produced during the electrochemical graining process. The layer is typically present in an amount of from 0.1-20 g/m2 and at a layer thickness of 0.1-4.0 &mgr;m, the particle sizes in the said layer generally falling in the range of from 10 to 2000 nm. Methods are disclosed for the preparation of said precursors via the electrochemical graining of aluminium substrates. The invention provides lithographic printing plate precursors which may be imagewise exposed by means of a high intensity laser beam to provide printing plates showing high durability on press and giving images which show good resolution and are free from background staining.

Abstract: The present invention provides several methods for engraving gravure cylinders much more rapidly and at a higher resolution while, at the same time, reducing the engraving cost. The present invention employs a resist that is deposited onto the surface of a gravure cylinder. The resist is capable of being physically and/or chemically changed in response to being exposed to a form of actinic energy, such as a laser beam. The exposed areas of resist allow a material, such as chromium, to be plated onto the surface of the gravure cylinder to form walls that define cells therebetween. In use, the cells contain ink for printing the desired patterns of text and/or images.

Abstract: Method for manufacturing an image-forming element having a hollow cylindrical drum body with a metallic outer layer and provided on its outer circumferential surface with a plurality of circumferentially extending electrodes which are electrically insulated from one another and from the drum body. The steps include cutting grooves into the metallic outer layer of the drum body, forming an insulating surface layer at least on the internal walls of the grooves by converting the surface of the metallic outer layer into an insulating substance, and filling the grooves with electrically conductive material.

Abstract: An aluminum support for a planographic printing plate is produced by (1) etching a surface of an aluminum plate chemically in an acidic or alkaline aqueous solution, (2) roughening the surface of the aluminum plate electrochemically in an acidic aqueous solution by applying DC voltage to form honeycomb pits having an average diameter from 0.5 to 10 .mu.m and to leave plateau portions, (3) etching the surface of the aluminum plate to render the plateau portions less than 10% of the surface, (4) roughening the surface of the aluminum plate electrochemically in an acidic aqueous solution using direct current or alternating current to form honeycomb pits having an average diameter from 0.1 to 2 .mu.m, (5) etching the surface of the aluminum plate chemically, and (6) anodizing the surface of the aluminum plate in an acidic solution. A low current density starting zone, or soft starting zone, may be provided at a first roughening stage.

Abstract: A plate-, foil- or web-shaped workpiece of aluminum or an alloy thereof is subjected, in an electrolyte bath, to an alternating current at a frequency of 0.1 to 25 Hz. During the AC treatment, an anodic potential is imposed on the workpiece, in the range of 0 to 5 Volts. The total charge input is 10 to 60 kC/m.sup.2. Prior to the electrochemical graining, the workpiece is mechanically grained. After the graining steps, an etching treatment as well as an anodical oxidation and, thereafter, a hydrophilization are performed.

Abstract: Smooth planar metal surfaces, usually an aluminum web, intended for a lithographic printing plate, are roughened by brush graining with fine abrasive particles which are hard and dense and have a radial or disk-like configuration such that the abrasive particles are forged into the surface of the metal forming cavities in which the abrasive particles remain embedded. The embedded abrasive particles are dislodged and removed from the cavities by subjecting the web to an anodic treatment employing electrolyte materials and concentrations, temperatures and voltage which will dislodge and remove the particles while retaining the surface texture or morphology of the as-roughened surface. The web is then subjected to a second anodic treatment under conditions which favor oxide formation in order to provide a final anodized product.

Abstract: A photosensitive lithographic printing plate requiring no fountain solution, which comprises an aluminum base and, formed thereon in the following order, a primer layer, a photosensitive layer, and a silicone rubber layer, wherein the aluminum base has a roughened surface with an average roughness (R.sub.a) of from 0.2 .mu.m to 0.8 .mu.m and a whiteness of from 0.10 to 0.35, and the primer layer is a homogeneous layer comprising a binder as the main component. The lithographic printing plate requiring no fountain solution is excellent in tone reproducibility, suitability for plate inspection, suitability for plate scanner examination, and press life.

Abstract: A planographic printing plate in which a design pattern is realized in a part of the back surface of a support for the planographic printing plate without any adverse influence on a photosensitive resin layer on the front surface thereof. After an aluminum support with a thickness of 0.24 mm is cleaned by degreasing and etching, an electrolytic aqueous solution is prepared to contain the nitric acid concentration of 10 g/l and the aluminum ion concentration of 7 g/l. In an electrolytic treatment cell 5, the back surface of the aluminum support is arranged so as to be faced to an electrode. A 1 mm-thick masking plate formed of an insulating material punched to provided openings with arbitrary shapes is brought into close contact with the back surface of the aluminum support so that the back surface of the aluminum support is covered with the masking plate. A carbon plate with a thickness of 50 mm is used as the electrode.

Abstract: A method for preparing a substrate for lithographic printing plates comprises the steps of forming a hydrated oxide layer on the surface of an aluminum plate and then anodizing the plate in a sulfuric acid electrolyte; a lithographic printing plate comprises the substrate; and the substrate per se prepared by the method is also disclosed herein.The presensitized plate for use in making lithographic printing plates which comprises the substrate has very high sensitivity which makes the presensitized plate applicable to new exposure methods and is capable of being developed with a developer of an aqueous solution system. The light-sensitive layer and the substrate of the presensitized plate are strongly adhered to one another and, therefore, the resulting lithographic printing plate has excellent printing durability and good printability.