Abstract: A metal regeneration method including: a melting furnace cleaning step of melting pure aluminum with an aluminum content of 99.5% by weight or higher in a melting furnace to clean the inside of the melting furnace; and a metal regeneration step of melting waste lithographic printing plates selected from unused lithographic printing plates and used lithographic printing plates, in the melting furnace whose inside has been cleaned by the melting furnace cleaning step, to obtain regenerated metal.

Abstract: According to the methods of the present invention, energy loss and yield loss can be significantly reduced and the quality of the aluminum purity and the trace metal contents can be ensured even when used planographic printing plates are reused. A recycling material with deposited substances removed therefrom is melted in a melting furnace into a recycled molten metal. The analyzed result obtained by analyzing the recycled molten metal is used to determine the mix proportions of the recycled molten metal, a fresh metal ingot, and a trace metal master alloy to be inputted into a pre-rolling melting furnace. The produced recycled molten metal in the molten state is inputted into the pre-rolling melting furnace to be mixed with the fresh metal ingot and the trace metal master alloy.

Abstract: A metal regeneration method including: a melting furnace cleaning step of melting pure aluminum with an aluminum content of 99.5% by weight or higher in a melting furnace to clean the inside of the melting furnace; and a metal regeneration step of melting waste lithographic printing plates selected from unused lithographic printing plates and used lithographic printing plates, in the melting furnace whose inside has been cleaned by the melting furnace cleaning step, to obtain regenerated metal.

Abstract: An IC tag is fixed to a printing plate. An ID code is stored in the IC tag. A used printing plate is collected using a collection container. The collection container is provided with a reception device of the collected used printing plates. The reception device is provided with an IC tag reader. An ID code of the used printing plate is read with the IC tag reader. According to the read ID code, whether to reuse the used printing plate for a substrate of the printing plate is judged. The used printing plates judged to be reused are sent to an aluminum substrate recycling plant and recycled as raw materials for aluminum used in production of the substrates for the printing plates.

Abstract: A process for producing an aluminum support for a lithographic printing plate, which comprises roughening an aluminum plate surface by a liquid honing process to form a first grain thereon and then modifying the first grain by a brush grinding process, and optionally, subjecting the modified surface to electrochemical graining. A printing plate using the aluminum support is excellent in printing durability and gives little background contamination.

Abstract: A process for producing an aluminum support for a lithographic printing plate, comprising chemical graining of an aluminum plate with an etching solution, is disclosed. The etching solution contains a mineral acid and an unsaturated concentration aluminum salt of a mineral acid. The printing plate produced from the support exhibits high printing durability and excellent performance in preventing stains in non-image areas.

Abstract: An emulsion type protective agent for the surface of a lithographic printing plate comprising an aqueous phase having dissolved therein a hydrophilic high molecular weight compound and an oil phase containing an organic solvent, an alkylphenyl type nonionic surfactant having an HLB less than 14 and an anionic surfactant.

Abstract: A light-sensitive lithographic printing plate comprising a support having on at least one surface thereof a light-sensitive layer, said light-sensitive layer exhibiting a higher oleophilicity (high affinity to grease) at the outermost surface thereof than in the balance of the light-sensitive layer. This light-sensitive lithographic printing plate is capable of beginning the printing operation with a relatively small number of spoilages and exhibits not only excellent press life but also high developability and excellent storage stability.

Abstract: A light-sensitive printing plate with a coating layer with an uneven pattern removable during development provided on the surface thereof, which can be brought into intimate contact with an original image in a short period of time by vacuum adhesion. The light-sensitive printing plate is produced by taking up a coating solution from a coating solution pan by a gravure roll, scraping away excess coating solution adhering to the gravure roll by a doctor blade, transferring the coating solution still retained on the gravure roll to a coating roll made of rubber with a fine uneven pattern on the surface thereof which is turning in the same direction and at the same speed as the gravure roll, and transferring the coating solution thus transferred to the coating roll to a support running at the same speed and in the same direction as the coating roll.

Abstract: An emulsion type protective agent for the surface of a lithographic printing plate comprising an aqueous phase having dissolved therein a hydrophilic high molecular weight compound and an oil phase containing an organic solvent, an alkylphenyl type nonionic surfactant having an HLB less than 14, an aliphatic acid ester type surfactant and an anionic surfactant.

Abstract: A light-sensitive printing plate having a matt layer, which is removable at development, on the surface thereof.

Abstract: An agent for protecting the surface of a lithographic printing plate which is an emulsion comprising an oil phase containing a plasticizer having a solidifying point of 15.degree. C. or less and a surfactant, and an aqueous phase having dissolved therein a hydrophilic high molecular weight compound.

Abstract: A light-sensitive printing plate with a coating layer with an uneven pattern removable during development provided on the surface thereof, which can be brought into intimate contact with an original image in a short period of time by vacuum adhesion. The light-sensitive printing plate is produced by taking up a coating solution from a coating solution pan by a gravure roll, scraping away excess coating solution adhering to the gravure roll by a doctor blade, transferring the coating solution still retained on the gravure roll to a coating roll made of rubber with a fine uneven pattern on the surface thereof which is turning in the same direction and at the same speed as the gravure roll, and transferring the coating solution thus transferred to the coating roll to a support running at the same speed and in the same direction as the coating roll.

Abstract: A photosensitive printing plate forming material having on its surface a matting layer composed of a resin and a fine particulate material dispersed therein, said resin being at least one member selected from rosin and rosin esters.

Abstract: A light-sensitive printing plate with a coating layer with an uneven pattern removable during development provided on the surface thereof, which can be brought into intimate contact with an original image in a short period of time by vacuum adhesion. The light-sensitive printing plate is produced by taking up a coating solution from a coating solution pan by a gravure roll, scraping away excess coating solution adhering to the gravure roll by a doctor blade, transferring the coating solution still retained on the gravure roll to a coating roll made of rubber with a fine uneven pattern on the surface thereof which is turning in the same direction and at the same speed as the gravure roll, and transferring the coating solution thus transferred to the coating roll to a support running at the same speed and in the same direction as the coating roll.

Abstract: A light-sensitive printing plate having a matt layer, which is removable at development, on the surface thereof.

Abstract: A light sensitive printing plate comprising a support having provided thereon a light sensitive layer and a matted layer, said matted layer being removable upon development and containing a light absorbing agent possessing an absorption in the spectral region to which the light-sensitive material coated on the light sensitive printing plate is sensitive.