Abstract: Method and apparatus for splicing together metal webs with the ends thereof being butted against each other or slightly lapped on each other. In the metal web splicing apparatus, there is provided a reduction roller which comprises a hold portion having a first radius and a projected portion having a second radius slightly greater than the first radius. With use of the reduction roller, while both sides of the weld spliced portion of the metal webs are being held and fixed by the hold portion of the roller, the weld spliced portion is rolled by the projected portion of the roller, thereby preventing escape of the rolled portion.

Abstract: A method of splicing together leading and following webs which are delivered successively. In the splicing method, when the leading and following webs are different in shape or material from each other, there is interposed between the leading and following webs a dummy web for increasing the strength of splicing of the webs. Also, when the leading and following webs are welded and spliced togethr, the two webs are in part lapped on each other and the lapped portions thereof are cut inclined with respect to the width direction of the webs. After waste materials produced from the cutting are removed, the ends of the webs are butted against each other or slightly lapped on each other and are then welded together. A welded and spliced portion, which includes a fusion portion and a recrystallized portion produced due to heat during welding, is formed such that a difference between the web thickness of the recrystallized portion and the thickness of the adjoining portions of the recrystallized portion is within .

Abstract: A process for producing support for aluminum printing-plate in which an aluminum support is electrochemically surface-roughed uses an alternating current in an acid electrolyte containing nitric acid. The alternating current has a waveform in which the frequency is within a range of 60 to 140 Hz and the ratio of an anode time t.sub.F to a period T, that is, t.sub.F /T, is within a range of 0.33 to 0.15, and this current is used as an electrolytic power source.

Abstract: A method of splicing together metal webs for use in planography with the ends thereof being butted or lapped against each other. In the metal web splicing method, the ends of the metal webs are spliced together in a butted manner, the splice portion thereof is welded, and the welded splice portion is rolled. According to the splicing method, there is left no level difference in the welded splice portion, which eliminates the possibility of the spliced metal webs being broken during the movement thereof and also has no ill effect on the coating process for the spliced metal webs.

Abstract: A method of preparing a support for a lithographic printing plate is described, which comprises roughening the support surface by laser irradiation performed under the condition that the support is placed in a liquid or in a gaseous atmosphere, thereby achieving improved stain resistance upon printing and excellent printing press life.

Abstract: A method of splicing together leading and following webs which are delivered successively. In the splicing method, when the leading and following webs are different in shape or material from each other, there is interposed between the leading and following webs a dummy web for increasing the strength of splicing of the webs. Also, when the leading and following webs are welded and spliced together, the two webs are in part overlapped on each other and the overlapped portions thereof are cut inclined with respect to the width direction of the webs. After waste materials produced from the cutting are removed, the ends of the webs are butted against each other or slightly overlapped on each other and then are welded together.

Abstract: A process for producing a support for a lithographic printing plate is described, which comprises jetting a high-pressure liquid from at least one nozzle at a high rate, joining the jetted stream with a slurry containing a fine abrasive powder having a specific gravity of not less than 2.5 and having a sharp-angled tip having a radius of not more than 20 .mu.m, said slurry being spouted from at least one spout, directing the resulting mixed stream to strike against a surface of a metal sheet to carry out first graining, and modifying the first roughness thus formed on the metal sheet by brush graining to form a second roughness. Lithographic printing plates produced by using the resulting support are free from stain formation during printing and exhibit satisfactory printing durability.

Abstract: A process for producing an aluminum support for a printing plate, which involves electrochemical graining of the support, is disclosed. The support is passed through an acidic electrolyte of an electrolytic cell along a path of travel maintained a distance above alternatingly distributed anodes and cathodes in a face-to-face relationship with the aluminum-containing support. Simultaneously, there is applied a d-c voltage between the alternating anodes and cathodes to produce an electrochemically roughened support.The electrochemically roughened supports produced in accordance with the invention have a grained structure. characterized by a uniform and dense distribution of high depth-to-diameter ratio pits and exhibit satisfactory print quality and running characteristic without causing any uneveness.

Abstract: A method of electrolytic surface treatment of aluminum supports for planographic printing plates, comprising the steps of: separating aluminum ions in an electrolyte for the surface treatment to the outside of a system using an ion-exchange membrane, and mixing the electrolyte after separation with a used electrolyte having high aluminum concentration, so that the aluminum ion concentration is adjusted to be constant in the electrolyte before use.

Abstract: The processing supports for lithographic printing plate is improved by an induction heating method while chemically and/or eldctric-chemically surface-treating the metal sheet or web to affect the surface roughness thereof.

Abstract: A process for producing a support for a lithographic printing plate is disclosed, comprising mechanically graining a sheet for the support with abrasive grains which have sharp-angled tips having a radius of not more than 20 .mu.m. The process is suitable for mass production, and the lithographic printing plate produced from the resulting support is excellent in stain-resistance and printing durability.

Abstract: A process for preparing a lithographic support, and the printing plate made therefrom, are described, wherein the process comprises the steps of (a) liquid-honing a surface of an aluminum sheet, and (b) electrochemically graining the surface of the aluminum sheet in an electrolyte comprises hydrochloric acid, nitric acid, or a mixture thereof.

Abstract: A process for producing an aluminum support for a lithographic printing plate is described, which comprises jetting a high-pressure liquid from at least one nozzle at a high rate, joining the jetted stream with a slurry containing a fine powder of an abrasive spouted from at least one spout, and directing the resulting mixed stream to strike against a surface of an aluminum plate to carry out cleaning and sandblasting at the same time.

Abstract: A method and apparatus for electrolytic treatment employing graphite electrodes wherein an asymmetrical waveform alternating current is applied to the electrodes to subject a metal web to a continuous electrolytic treatment. A graphite electrode in a treatment section is arranged confronting the metal web. Two graphite electrodes in current supply sections are arranged respectively upstream and downstream of the graphite electrode in the treatment section relative to a direction of movement of the metal web. Two auxiliary anode electrodes in the current supply sections are arranged respectively upstream and downstream of the two graphite electrodes in current supply sections. A part of an asymmetrical alternating waveform current is supplied to the auxiliary anode electrodes so that a current causing a cathode reaction on the surfaces of the graphite electrodes is made larger than a current causing an anode reaction thereon.

Abstract: A method for continuously electrolytically processing a metal web in which the consumption rate of graphite electrodes is remarkably reduced. Auxiliary anodes made of a nonreactive material are provided separately from the graphite electrodes. One half of a symmetrical waveform is applied directly between the graphite electrodes, while for the other half of the waveform, a portion of the current is distributed through the auxiliary anodes. In this manner, the magnitude of the current contributing to a cathode reaction on the surfaces of the graphite electrodes is made larger than the magnitude of the current contributing to an anode reaction on the surfaces of the graphite electrodes, thereby reducing the consumption rate of the graphite electrodes.

Abstract: A web conveying method and apparatus in which a metal web is maintained substantially parallel to an adjacent electrode despite fluctuations in the flow of an electrolytic solution in which the web is immersed. A guide plate is disposed adjacent the web on the side thereof opposite the electrode. A plurality of through-holes are formed in the guide plate which are evenly distributed thereon. Due to the flow of solution through the guide plate, a static pressure is applied to the web which maintains it substantially parallel at all times to the electrode.

Abstract: A method and apparatus for electrolytic treatment to a metal web includes transporting the metal web between pairs of electrolytic-plates which are immersed in an electrolyzer. A plurality of insulating members extends from upper surface or bottom of the electrolyzer along a widthwise direction of the metal web, and the insulating members function to interrupt a flow of the electrolyte which is circulated in the electrolyzer which increases the agitation rate of the electrolyte in the vicinity of the surfaces of the metal web.

Abstract: A web conveying method and apparatus in which a metal web is maintained substantially parallel to an adjacent electrode despite fluctuations in the flow of an electrolytic solution in which the web is immersed. A guide plate is disposed adjacent the web on the side thereof opposite the electrode. A plurality of through-holes are formed in the guide plate which are evenly distributed thereon. Due to the flow of solution through the guide plate, a static pressure is applied to the web which maintains it substantially parallel at all times to the electrode.

Abstract: An electrolytic processing device in which either or both surfaces of a belt-shaped metal plate can be selectively subjected to an electrolytic process. In a first electrolytic processing operation wherein only one surface of the belt-shaped metal plate is subjected to processing, an electrical insulating member is disposed between the belt-shaped metal plate and a first group of electrodes arranged over the surface of the belt-shaped metal plate to thereby suppress the flow of current between the belt-shaped metal plate and the first group of electrodes. In a second electrolytic processing operation in which both surfaces of the belt-shaped metal plate are subjected to processing, the electrical insulating member is removed from the position between the electrodes and the belt-shaped metal plate to thereby allow current to flow from the electrodes to both surfaces of the belt-shaped metal plate.