Abstract: The invention provides a standard image pattern for controlling a process of making printing plates, having at least: a plurality of AM halftone images, each of which is formed of dots according to Amplitude Modulation Screening, and each of which has an area coverage that is different from that of the others; and a plurality of FM halftone images, which are formed of dots according to Frequency Modulation Screening, which are respectively adjacent to the plurality of the AM halftone images, and which have a predetermined area coverage. The invention further provides a method for evaluating a developer for a planographic printing plate using the standard developer and a method for controlling quality of a planographic printing plate using the standard developer.

Abstract: A method for evaluating planographic printing plates according to the present invention includes: a step (A) of exposing a planographic printing plate precursor by irradiating a thin-line image of a one-pixel line and at least one thin-line image selected from two- to eight-pixel lines by incrementally altering the plate-surface energy; developing the exposed plate precursor with a standard developer; and identifying an exposure intensity (hereinafter, “thin-line sensitivity”) that respectively provides the images thus formed, with the same density; a step (B) of preparing another planographic printing plate precursor under the same conditions as in the step (A) and identifying the thin-line sensitivity, except that the planographic printing plate precursor is developed with a test developer; a step (C) of comparing the thin-line sensitivities respectively obtained in the steps (A) and (B); and a step (D) of adjusting plate-making conditions when the results of the comparison in the step (C) show a difference

Abstract: A method for evaluating planographic printing plates according to the present invention includes: a step (A) of exposing a planographic printing plate precursor by irradiating a thin-line image of a one-pixel line and at least one thin-line image selected from two- to eight-pixel lines by incrementally altering the plate-surface energy; developing the exposed plate precursor with a standard developer; and identifying an exposure intensity (hereinafter, “thin-line sensitivity”) that respectively provides the images thus formed, with the same density; a step (B) of preparing another planographic printing plate precursor under the same conditions as in the step (A) and identifying the thin-line sensitivity, except that the planographic printing plate precursor is developed with a test developer; a step (C) of comparing the thin-line sensitivities respectively obtained in the steps (A) and (B); and a step (D) of adjusting plate-making conditions when the results of the comparison in the step (C) show a difference

Abstract: An image evaluation method of the planographic printing plate comprises the steps of (A) producing a standard developer-treated planographic printing plate by preparing a planographic printing plate precursor comprising a substrate and a photosensitive layer, which includes an aqueous alkaline solution-soluble resin and a compound that absorbs light and generates heat, on the substrate, exposing the planographic printing plate precursor under a condition that forms a checkerboard image of rectangles having one side that is 5 to 50 &mgr;m in length, and then developing the image with a standard developer; (B) producing a subject developer-treated planographic printing plate in the same manner as the above-mentioned step (A) except the development is carried out with a subject developer to be evaluated; and (C) comparing the above-mentioned checkerboard images resulted from the standard developer-treated planographic printing plate, with that resulted from the subject developer-treated planographic printing pla

Abstract: A clearance between an upper knife and a lower knife of a slitter is set at 30 to 100 &mgr;m, and the slitter cuts a sensitized printing plate. In the sensitized printing plate cut by the slitter, there is a shear droop which is 20 to 30 &mgr;m high at the cut part, and a burr which is less than 50 &mgr;m high. If the maximum height of a surface roughness of a cut surface of the sensitized printing plate is 1.2 &mgr;m to 12 &mgr;m on the average, a hydrophilic property of the cut part improves and the stain of a frame can be decreased.

Abstract: A quality control method for a planographic printing plate having disposed on a substrate a photosensitive layer formed by a resin soluble in an aqueous alkali solution and a compound that absorbs light to generate heat, the quality control method having the steps of: (A) exposing, to an ultraviolet ray, a gray scale for evaluating a positive type planographic printing plate made by exposure to an ultraviolet ray, followed by development with a standard developing solution having a standard formula, and measurement of the sensitivity of the gray scale processed by the standard developing solution; (B) exposing, to an ultraviolet ray, a gray scale for evaluating a positive type planographic printing plate made by exposure to an ultraviolet ray in the same manner as in the step (A), followed by development with a developing solution to be evaluated, and measurement of the sensitivity of the gray scale processed by the developing solution to be evaluated; (C) comparing the sensitivity of the gray scale processed

Abstract: A clearance between an upper knife and a lower knife of a slitter is set at 30 to 100 &mgr;m, and the slitter cuts a sensitized printing plate. In the sensitized printing plate cut by the slitter, there is a shear droop which is 20 to 30 &mgr;m high at the cut part, and a burr which is less than 50 &mgr;m high. If the maximum height of a surface roughness of a cut surface of the sensitized printing plate is 1.2 &mgr;m to 12 &mgr;m on the average, a hydrophilic property of the cut part improves and the stain of a frame can be decreased.

Abstract: A clearance between an upper knife and a lower knife of a slitter is set at 30 to 100 &mgr;m, and the slitter cuts a sensitized printing plate. In the sensitized printing plate cut by the slitter, there is a shear droop which is 20 to 30 &mgr;m high at the cut part, and a burr which is less than 50 &mgr;m high. If the maximum height of a surface roughness of a cut surface of the sensitized printing plate is 1.2 &mgr;m to 12 &mgr;m on the average, a hydrophilic property of the cut part improves and the stain of a frame can be decreased.

Abstract: Light-sensitive compositions comprise a light-sensitive diazo resin, a binder and a compound having a pivaloyl group. Lithographic printing plates prepared by using the light-sensitive compositions of the invention are excellent in ink receptivity.

Abstract: A process for preparing a positive-acting photosensitive lithographic printing plate precursor is described, comprising a combination of the steps of (a) electrolytically graining an aluminum plate in a nitric acid-based electrolyte, (b) etching the grained plate with an alkali, (c) anodizing the etched plate, and (d) forming a photosensitive layer containing an o-quinonediazide on the anodized plate.

Abstract: A negative working light-sensitive composition and a lithographic printing plate using the composition are described. The printing plate is comprised of a hydrophilic support and a thin layer of a negative working light-sensitive composition on the support. The light-sensitive composition contains a light-sensitive diazo compound and a compound capable of increasing absorption over the light-sensitive wavelength region of the composition with increasing exposure time.