# US 6,484,634 B1 · Block copy sheet for lithographic printing plate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,484,634 B1 - Document ID: US6484634B1 - Status: Granted - Kind: B1 - Application number: 09/652,790 - Filed: 2000-08-31 - Granted: 2002-11-26 - Earliest claimed: 1999-09-01 - Assignees: Fuji Photo Film Co., Ltd. - Inventors: Seishi Kasai; Takao Nakayama; Hiroyuki Ohishi - Web page: https://patentgrep.com/patent/US6484634B1 ## CPC - B41N 6/00: Mounting boards; {Sleeves} Make-ready devices, e.g. underlays, overlays; Attaching by chemical means, e.g. vulcanising - B41N: PRINTING PLATES OR FOILS (photosensitive material G03); MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM ## Abstract A block copy sheet for lithographic printing plate to be interposed between a plate cylinder and a lithographic printing plate having a front surface and a back surface, at least the back surface being made of a material other than metals, wherein the block copy sheet have convex portions provided on a surface thereof, the convex portions having a predetermined shape so as to concave the back surface of the lithographic printing plate when pressed against the back surface of the lithographic printing plate, and wherein (1) the convex portions comprises a composite particle having protrusions provided on the surface thereof and having a hardness greater than that of the back surface of the lithographic printing plate and a particle diameter of from 1 μm to 100 μm, or (2) the convex portions comprises non-spherical fillers having an average length of from 1 μm to 200 μm and the contact area of the convex portions and the back surface of the lithographic printing plate is from 0.6% to 3.0% of the area of the back surface of the lithographic printing plate. ## Claims ### Claim 1 A block copy sheet for lithographic printing plate to be interposed between a plate cylinder and a lithographic printing plate having a front surface and a back surface, at least the back surface being made of a material other than metals, wherein said block copy sheet have convex portions provided on a surface thereof, said convex portions having a predetermined shape so as to concave the back surface of the lithographic printing plate when pressed against the back surface of the lithographic printing plate, and wherein said convex portions comprises a composite particle having protrusions provided on the surface thereof and having a hardness greater than that of the back surface of the lithographic printing plate and a particle diameter of from 1 μm to 100 μm. ### Claim 2 (depends on 1) The block copy sheet according to claim 1, wherein said composite particle comprises an inorganic material having a particle diameter of from 1 μm to 100 μm. ### Claim 3 (depends on 2) The block copy sheet according to claim 2, wherein said inorganic material is selected from the group consisting of glass, oxides and sulfides. ### Claim 4 (depends on 1) The block copy sheet according to claim 1, wherein said composite particle comprises an organic material having a particle diameter of from 1 μm to 100 μm. ### Claim 5 (depends on 4) The block copy sheet according to claim 4, wherein said organic material is selected from the group consisting of acrylic resin, polyethylene, polypropylene, and polystyrene. ### Claim 6 (depends on 1) The block copy sheet according to claim 1, wherein said composite particle comprises an organic-inorganic composite material having a particle diameter of from 1 μm to 100 μm. ### Claim 7 (depends on 1) The block copy sheet according to claim 1, wherein the sum of the maximum sectional area of said convex portions parallel to the surface of the sheet per unit area is from 0.05% to 4%. ### Claim 8 (depends on 1) The block copy sheet according to claim 1, wherein said composite particle has a particle diameter of from 3 to 80 μm. ### Claim 9 (depends on 1) The block copy sheet according to claim 1, wherein said composite particle has a particle diameter of from 5 to 50 μm. ### Claim 10 A block copy sheet for lithographic printing plate to be interposed between a plate cylinder and a lithographic printing plate having a front surface and a back surface, at least the back surface being made of a material other than metals, wherein said block copy sheet have convex portions provided on a surface thereof, said convex portions having a predetermined shape so as to concave the back surface of the lithographic printing plate when pressed against the back surface of the lithographic printing plate, wherein the contact area of said convex portions and the back surface of the lithographic printing plate is from 0.6% to 3.0% of the area of the back surface of the lithographic printing plate, and wherein said convex portions comprises non-spherical fillers having an average length of from 1 μm to 200 μm. ### Claim 11 (depends on 10) The block copy sheet according to claim 10, wherein said non-spherical fillers have a tabular shape. ### Claim 12 (depends on 11) The block copy sheet according to claim 11, wherein said tabular-shaped fillers comprise at least one member selected from the group consisting of talc, mica, glass flake and synthetic hydrotalcite. ### Claim 13 (depends on 10) The block copy sheet according to claim 10, wherein said non-spherical fillers have an acicular shape. ### Claim 14 (depends on 13) The block copy sheet according to claim 13, wherein said acicular-shaped fillers comprise at least one member selected from the group consisting of wollastonite, potassium titanate, basic magnesium sulfate, sepiolite, xonotlite and aluminum borate. ### Claim 15 (depends on 10) The block copy sheet according to claim 10, wherein said non-spherical fillers have a tetrapod shape. ### Claim 16 (depends on 15) The block copy sheet according to claim 15, wherein said tetrapod-shaped fillers comprise zinc oxide. ### Claim 17 (depends on 10) The block copy sheet according to claim 10, wherein said non-spherical fillers have an average length of from 3 μm to 100 μm.