Abstract: Disclosed is a support for a lithographic printing plate, wherein an adhering amount of a rare-earth element atom to a surface thereof is 0.1 to 20 mg/mg2, and a presensitized plate provided with an image recording layer on the support for a lithographic printing plate. The presensitized plate achieving both high scum resistance and long press life can be realized, which is the same in the case the image recording layer containing an infrared absorbent, where scum would easily occur, is provided onto the support.

Abstract: Disclosed is a support for a lithographic printing plate, wherein an adhering amount of a rare-earth element atom to a surface thereof is 0.1 to 20 mg/mg2, and a presensitized plate provided with an image recording layer on the support for a lithographic printing plate. The presensitized plate achieving both high scum resistance and long press life can be realized, which is the same in the case the image recording layer containing an infrared absorbent, where scum would easily occur, is provided onto the support.

Abstract: A substrate for a planographic printing plate and a method of fabrication thereof. After a surface roughening treatment and before an anodizing treatment, an aluminum alloy plate to be used as the substrate is washed in an alkali solution, and then in an acidic solution. After surface-roughening, overlap points of Fe and Si macularly distributed at the surface of the aluminum alloy plate have a surface coverage of not more than 0.5%, and there are no more than 800 per 1 mm2 of overlap points which have sizes larger than 1.6×10−7 mm2. The planographic printing plate of the present invention has excellent printing capabilities in that, irrespective of printing conditions, soiling does not occur at a non-image portion of the planographic printing plate.

Abstract: An aluminum alloy support for a planographic printing plate is disclosed, which is an aluminum alloy plate comprising 0<Fe.ltoreq.0.20 wt %, 0.ltoreq.Si.ltoreq.0.13 wt %, Al.gtoreq.99.7 wt % and the balance of inevitable impurity elements, wherein the number of intermetallic compounds present in the arbitrary thickness direction with in 10 .mu.m from the plate surface is from 100 to 3,000 per mm.sup.2 and the intermetallic compound has an average particle size of from 0.5 to 8 .mu.m, with the intermetallic compounds having a particle size of 10 .mu.m or more being in a proportion by number of 2% or less. Also disclosed is a method for producing the above-described aluminum alloy support.

Abstract: A support for a planographic printing plate support in which variations in the quality of the material of the aluminum support are reduced to thereby improve the yield in an electrolytic graining treatment and which is excellent in susceptibility to graining, has no stripe irregularities, and excellent appearance, and a method for producing such a planographic printing plate. An aluminum plate material is formed through a twin-roller continuous casting apparatus and subjected to cold rolling. Successively, the plate is subjected to heat treatment so as to form a surface portion of a depth of at least 15 .mu.m in the thickness direction having no recrystallization in the surface layer. If necessary, the plate may be subjected to cold rolling again as final rolling. Thereafter, the plate is subjected to correction.

Abstract: Method and apparatus for splicing together the ends of metal webs by TIG welding. In the method and apparatus, since the tapered end portion of an electrode disposed at the leading end of a welding torch for use in TIG welding is formed in a semi-spherical shape or in a circular flat surface, arc can remain stable even if the length of the arc in the TIG welding is changed suddenly at the welding starting or terminating end portion of the weldedly spliced portion of the metal webs.

Abstract: A method of producing a support for a planographic printing plate, which reduces the scattering in the material of the aluminum support, improves the yield of the electrolytic surface graining treatment, and is able to produce lithographic printing plates having superior surface graining aptitude. Aluminum material with a width of 1000 mm and a thickness of 6 mm is formed in the continuous casting twin-roller thin plate device. It is then cold rolled to a plate thickness of 3 mm, and after conducting annealing at 400.degree. C., cold rolling (including correction) is further conducted to bring it to 0.3 mm and form the samples. The temperature distribution of the molten metal at the outlet of the molten metal supply nozzle is kept within a predetermined range.

Abstract: A support for a planographic printing plate support in which variations in the quality of the material of the aluminum support are reduced to thereby improve the yield in an electrolytic graining treatment and which is excellent in susceptibility to graining, has no stripe irregularities, and excellent appearance, and a method for producing such a planographic printing plate. An aluminum plate material is formed through a twin-roller continuous casting apparatus and subjected to cold rolling. Successively, the plate is subjected to heat treatment so as to form a surface portion of a depth of at least 15 .mu.m in the thickness direction having no recrystallization in the surface layer. If necessary, the plate may be subjected to cold rolling again as final rolling. Thereafter, the plate is subjected to correction.

Abstract: A method of producing a planographic printing plate support in which after aluminum is continuously cast directly from molten aluminum into a thin aluminum plate, the aluminum thin plate is subjected to cold rolling, heat treatment and flattening to obtain an aluminum support. The aluminum support is then subjected to surface toughening. The components of the aluminum support areFe: 0.4%-0.2%,Si: 0.20%-0.05%,Cu: not larger than 0.02%, and the Al purity is not smaller than 99.5%. After continuous casting, Fe in a range of from 20% to 90% of the Fe total content exists in a grain boundary and the rest of Fe exists as a solid solution in grains. In this case, it is preferable that in a section perpendicular to the direction of continuous casting, the grain size is in a range of from 2 .mu.m to 500 .mu.m.

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 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.