# US 12,761,408 B2 · Polygon mirror, optical deflector, optical scanning device, and image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,761,408 B2 - Document ID: US12761408B2 - Status: Granted - Kind: B2 - Application number: 18/174,141 - Filed: 2023-02-24 - Published: 2023-09-07 - Granted: 2026-10-13 - Earliest claimed: 2022-03-03 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Atsushi Takata - Web page: https://patentgrep.com/patent/US12761408B2 ## CPC - G02B 5/0816: {Multilayer mirrors, i.e. having two or more reflecting layers (G02B5/0883, G02B5/0891 take precedence)} - G02B 26/121: {Mechanical drive devices for polygonal mirrors} - G03G 15/0435: {by introducing an optical element in the optical path, e.g. a filter} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract Provided is a polygon mirror that includes a resin member including a first surface, a second surface opposite to the first surface, a through-hole extending from the first surface to the second surface, an inner side surface, which intersects with the first and second surfaces, surrounding the through-hole, outer side surfaces, each of which intersects with the first and second surfaces on an opposite side of the inner side surface, and a die piece division line surrounding the through-hole and disposed on the second surface. The second surface intersects with the individual outer side surfaces at intersection lines. The intersection lines include first and second intersection lines intersecting with the first intersection line at an intersection, which is a first corner portion. The die piece division line is provided closer to the through-hole than a first midpoint between the inner side surface and the first corner portion. ## Claims ### Claim 1 A polygon mirror comprising a resin member, the resin member including: a first surface; a second surface opposite to the first surface; a through-hole extending from the first surface to the second surface; an inner side surface, which intersects with the first surface and the second surface, surrounding the through-hole; a plurality of outer side surfaces, each of which intersects with the first surface and the second surface on an opposite side of the inner side surface; and a die piece division line surrounding the through-hole and disposed on the second surface, wherein the die piece division line is closer to the outer side surfaces than the through-hole, wherein the second surface intersects with the individual outer side surfaces at intersection lines, wherein the intersection lines include a first intersection line and a second intersection line that intersects with the first intersection line at an intersection, which is a first corner portion, and wherein the die piece division line is provided closer to the through-hole than a first midpoint between the inner side surface and the first corner portion. ### Claim 2 (depends on 1) The polygon mirror according to claim 1, wherein the die piece division line is provided closer to the through-hole than a line segment connecting a second midpoint and a third midpoint adjacent to the second midpoint among midpoints lying between the inner side surface and the outer side surfaces on line segments radially connecting a center of the through-hole and the outer side surfaces. ### Claim 3 (depends on 1) The polygon mirror according to claim 1, wherein the die piece division line is provided closer to the through-hole than a line segment connecting a fourth midpoint and the first midpoint, the fourth midpoint lying between the inner side surface and a second corner portion sharing a corresponding outer side surface of the outer side surfaces with the first corner portion. ### Claim 4 (depends on 1) The polygon mirror according to claim 1, wherein an area of a region between the die piece division line and the through-hole is smaller than two-thirds of an area of a region surrounded by the die piece division line. ### Claim 5 (depends on 1) The polygon mirror according to claim 1, wherein the die piece division line is provided at a position of 0.2 mm or more away from the through-hole. ### Claim 6 (depends on 1) The polygon mirror according to claim 1, wherein the die piece division line is provided closer to the through-hole than a line segment connecting a fifth midpoint between the inner side surface and a first outer side surface among the outer side surfaces and a sixth midpoint between the inner side surface and a second outer side surface adjacent to the first outer side surface. ### Claim 7 (depends on 1) The polygon mirror according to claim 1, wherein the die piece division line has a non-circular shape. ### Claim 8 (depends on 1) The polygon mirror according to claim 1, wherein the die piece division line includes a plurality of straight lines and a curved line. ### Claim 9 (depends on 8) The polygon mirror according to claim 8, wherein the die piece division line has a rounded portion at which the straight lines of the die piece division line are connected to each other and has a rounded portion at which each of the straight lines and a curved line is connected to each other. ### Claim 10 (depends on 1) The polygon mirror according to claim 1, wherein the through-hole has a non-circular shape. ### Claim 11 (depends on 1) The polygon mirror according to claim 1, wherein the through-hole on the first surface is identical in shape to the through-hole on the second surface. ### Claim 12 (depends on 1) The polygon mirror according to claim 1, wherein, a shape of the through-hole on the first surface and a shape of the through-hole on the second surface are formed by a straight line and a curved line. ### Claim 13 (depends on 1) The polygon mirror according to claim 1, wherein, on the second surface, the through-hole and the die piece division line each have a shape including at least one straight line, and wherein the at least one straight line included in the through-hole and the at least one straight line included in the die piece division line form an angle of less than 15 degrees. ### Claim 14 (depends on 13) The polygon mirror according to claim 13, wherein a number of straight lines included in a shape of the through-hole equals a number of straight lines included in a shape of the die piece division line. ### Claim 15 (depends on 1) The polygon mirror according to claim 1, wherein a region from the die piece division line to the through-hole on the second surface is recessed toward the first surface with respect to a region from the die piece division line to the outer side surfaces. ### Claim 16 (depends on 1) The polygon mirror according to claim 1, wherein an intersection line between the second surface and the outer side surfaces is used as a reference of a height in a direction from the second surface to the first surface, and wherein a region from the die piece division line to the through-hole on the second surface is recessed toward the first surface with respect to the reference. ### Claim 17 (depends on 1) The polygon mirror according to claim 1, wherein an area of a region between the die piece division line and the through-hole is smaller than an area of the through-hole on a plane including the second surface. ### Claim 18 (depends on 1) An optical deflector comprising: the polygon mirror according to claim 1; and a drive source configured to rotate the polygon mirror. ### Claim 19 (depends on 18) An optical scanning device comprising: a light source; and the optical deflector according to claim 18 configured to deflect light emitted from the light source. ### Claim 20 (depends on 19) An image forming apparatus comprising an image forming unit configured to form an image on a sheet, wherein the image forming unit includes an image carrier and the optical scanning device according to claim 19 configured to scan a surface of the image carrier with light.