Abstract: The present invention provides a planographic printing plate manufacturing apparatus comprising: a cutting process section which cuts a web in a thickness direction of the web by pinching the web with at least a pair of an upper knife and a lower knife, wherein the lower knife includes a flat part supporting a center of the web, a decline part gradually declined an upper end toward outside from the flat part and a cutting edge part having an upper end gradually raised toward outside from the decline part to be a cutting edge, an angle of the lower knife at a boundary point between the decline part and the flat part is 135° or more, a boundary point between the decline part and the cutting edge part is provided so as to be greater or equal to a droop width of a lower surface of a cut product.

Abstract: The present invention provide a planographic printing plate (2) cutting method for cutting a sheaf (1) of a plurality of planographic printing plates (2) by pressing down a cutting blade (12), wherein a moving speed of an edge of the cutting blade (12) moving across the sheaf (1) of the planographic printing plates (2) is equal to or not less than 205 mm/s but equal to or not more than 260 mm/s. Therefore, the sticking of aluminum to the edge of the cutting blade (12) is prevented and thereby preventing from damaging the cut faces of the planographic printing plate (2), even if the large number of the planographic printing plate (2) are cut.

Abstract: The present invention provides a planographic printing plate manufacturing apparatus comprising: a cutting process section which cuts a web in a thickness direction of the web by pinching the web with at least a pair of an upper knife and a lower knife, wherein the lower knife includes a flat part supporting a center of the web, a decline part gradually declined an upper end toward outside from the flat part and a cutting edge part having an upper end gradually raised toward outside from the decline part to be a cutting edge, an angle of the lower knife at a boundary point between the decline part and the flat part is 135° or more, a boundary point between the decline part and the cutting edge part is provided so as to be greater or equal to a droop width of a lower surface of a cut product.

Abstract: According to the present invention, the droop height is set to 25 to 70 ?m, a knife having an acute angle of 70° or more is used as the lower knife, and the level difference angle of the lower knife is set to 5° or less. Thereby, it is possible to prevent stain from being formed on a planographic printing plate, while securing the predetermined droop height. At the same time, it is possible to suppress the generation of a burr, and to prevent a flaw from being caused at the time when the planographic printing plates are stacked.

Abstract: It is an object of the present invention to provide a protecting/packaging material for a lithographic printing plate capable of preventing the toning of the lithographic printing plate and a method for packaging the lithographic printing plate. In a protecting/packaging material for protecting and/or packaging a lithographic printing plate, a chlorine concentration contained in a inter leaf, protective pasteboard or package paper for the lithographic printing plate used with the lithographic printing plate brought into contact with a photosensitive layer of the lithographic printing plate is set to 1.5% by weight or less.

Abstract: A cutting blade is used for press-cutting a stack of layered sheets and has an edge portion formed of a high-speed steel powder sintered body.

Abstract: The present invention discloses a planographic printing plate having a notched portion on its surface having a required size, and having smaller burrs at a rear face, and a planographic printing plate cutting device and a planographic printing plate cutting method for forming such a planographic printing plate by cutting. The planographic printing plate cutting device of the present invention includes an upper roller for forming a recessed section at the planographic printing plate. The upper roller, which is formed substantially into a disc shape as a whole, has a pressing portion parallel to a web (the planographic printing plate), and a slope portion that is slanted with respect to the surface of the web at a predetermined inclination. This upper roller presses the web such that a sloped face (recessed section) that is slanted with respect to the surface of the web is formed. Next, a shearing roller shears the web at the sloped face such that a remaining portion of the sloped face forms a notched portion.

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: The present invention discloses a planographic printing plate having a notched portion on its surface having a required size, and having smaller burrs at a rear face, and a planographic printing plate cutting device and a planographic printing plate cutting method for forming such a planographic printing plate by cutting. The planographic printing plate cutting device of the present invention includes an upper roller for forming a recessed section at the planographic printing plate. The upper roller, which is formed substantially into a disc shape as a whole, has a pressing portion parallel to a web (the planographic printing plate), and a slope portion that is slanted with respect to the surface of the web at a predetermined inclination. This upper roller presses the web such that a sloped face (recessed section) that is slanted with respect to the surface of the web is formed. Next, a shearing roller shears the web at the sloped face such that a remaining portion of the sloped face forms a notched portion.

Abstract: The present invention discloses a planographic printing plate having a notched portion on its surface having a required size, and having smaller burrs at a rear face, and a planographic printing plate cutting device and a planographic printing plate cutting method for forming such a planographic printing plate by cutting. The planographic printing plate cutting device of the present invention includes an upper roller for forming a recessed section at the planographic printing plate. The upper roller, which is formed substantially into a disc shape as a whole, has a pressing portion parallel to a web (the planographic printing plate), and a slope portion that is slanted with respect to the surface of the web at a predetermined inclination. This upper roller presses the web such that a sloped face (recessed section) that is slanted with respect to the surface of the web is formed. Next, a shearing roller shears the web at the sloped face such that a remaining portion of the sloped face forms a notched portion.

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.