# US 2026/0064033 A1 · Light scanning apparatus and image forming apparatus including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0064033 A1 - Document ID: US20260064033A1 - Status: Published application - Kind: A1 - Application number: 19/303,748 - Filed: 2025-08-19 - Published: 2026-03-05 - Earliest claimed: 2024-08-30 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Kazumi KIMURA; Hiroki YOSHIDA; Hayato KATO - Web page: https://patentgrep.com/patent/US20260064033A1 ## CPC - G03G 15/0435: {by introducing an optical element in the optical path, e.g. a filter} - G02B 26/123: {Multibeam scanners, e.g. using multiple light sources or beam splitters} - G02B 26/125: {Details of the optical system between the polygonal mirror and the image plane (G02B26/123, G02B26/127 take precedence; F-Theta lenses G02B13/0005)} - G03G 15/04072: {by laser} - G03G 15/0409: {Details of projection optics (for projection printing apparatus G03B27/522)} - G03G 2215/0404: Laser - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A light scanning apparatus according to the present disclosure includes a deflecting unit configured to deflect a light flux from a light source to scan a surface in a main scanning direction, and a first optical system configured to guide the light flux deflected by the deflecting unit to the surface to be scanned, in which a width of the light flux immediately before being incident on a first deflecting surface of the deflecting unit is smaller than a width of the first deflecting surface in a main scanning cross section, and only a part of the light flux incident on the deflecting unit is deflected toward the surface to be scanned by the first deflecting surface when the first deflecting surface is at a first angle in the main scanning cross section. ## Claims ### Claim 1 A light scanning apparatus, comprising: a deflecting unit configured to deflect a light flux from a light source to scan a surface in a main scanning direction; and a first optical system configured to guide the light flux deflected by the deflecting unit to the surface to be scanned, wherein a width of the light flux immediately before being incident on a first deflecting surface of the deflecting unit is smaller than a width of the first deflecting surface in a main scanning cross section, and wherein only a part of the light flux incident on the deflecting unit is deflected toward the surface to be scanned by the first deflecting surface when the first deflecting surface is at a first angle in the main scanning cross section. ### Claim 2 (depends on 1) The light scanning apparatus according to claim 1, further comprising a light receiving element configured to receive the part of the light flux deflected by the first deflecting surface at the first angle, wherein the light receiving element is arranged on the same side as the light source with respect to an optical axis of the first optical system in the main scanning cross section. ### Claim 3 (depends on 1) The light scanning apparatus according to claim 1, further comprising: a second optical system configured to cause the light flux from the light source to be incident on the deflecting unit; a light receiving element configured to receive the part of the light flux deflected by the first deflecting surface at the first angle; and an optical element configured to guide the part of the light flux deflected by the first deflecting surface at the first angle to the light receiving element, wherein a width of an incident surface of the optical element is smaller than a width of an optical surface closest to the deflecting unit on an optical path of the second optical system in the main scanning cross section. ### Claim 4 (depends on 1) The light scanning apparatus according to claim 1, further comprising: a light receiving element configured to receive the part of the light flux deflected by the first deflecting surface at the first angle; and a reflecting element configured to reflect the part of the light flux deflected by the first deflecting surface at the first angle, wherein a following condition is satisfied: θ BD < θ BDm where θBD represents an angle formed by a traveling direction of a principal ray of the light flux immediately before being incident on the reflecting element with respect to an optical axis of the first optical system in the main scanning cross section, and θBDm represents an angle formed by the traveling direction of the principal ray of the light flux immediately after being reflected by the reflecting element with respect to the optical axis of the first optical system in the main scanning cross section. ### Claim 5 (depends on 4) The light scanning apparatus according to claim 4, wherein a following condition is satisfied: θ BD < θ i ≤ θ BDm where θi represents an angle formed by the traveling direction of the principal ray of the light flux immediately before being incident on the deflecting unit with respect to the optical axis of the first optical system in the main scanning cross section. ### Claim 6 (depends on 1) The light scanning apparatus according to claim 1, wherein another portion of the light flux which is not deflected by the first deflecting surface among the light flux incident on the deflecting unit is deflected by a second deflecting surface adjacent to the first deflecting surface when the first deflecting surface is at the first angle. ### Claim 7 (depends on 1) The light scanning apparatus according to claim 1, wherein only a part of the light flux incident on the deflecting unit is deflected toward the surface to be scanned by the first deflecting surface when the first deflecting surface is at a second angle in the main scanning cross section. ### Claim 8 (depends on 7) The light scanning apparatus according to claim 7, wherein the part of the light flux deflected by the first deflecting surface at the second angle travels to an effective region of the surface to be scanned. ### Claim 9 (depends on 8) The light scanning apparatus according to claim 8, wherein the part of the light flux deflected by the first deflecting surface at the second angle travels to an outermost off-axis image height on a side of the surface to be scanned opposite to a side on which the light source is arranged. ### Claim 10 (depends on 1) The light scanning apparatus according to claim 1, wherein a following condition is satisfied: 5.5 ≤ φ - K × N × ( N - 1 ) ≤ 13. where φ [mm] represents a diameter of a circumscribed circle in the main scanning cross section of the deflecting unit, N represents a number of deflecting surfaces of the deflecting unit, and K represents a predetermined value of 0.52 or more and 0.56 or less. ### Claim 11 (depends on 1) The light scanning apparatus according to claim 1, wherein a width of the part of the light flux deflected by the first deflecting surface at the first angle is smaller than a width of the light flux immediately before being incident on the first deflecting surface in the main scanning cross section. ### Claim 12 (depends on 1) The light scanning apparatus according to claim 1, wherein a following condition is satisfied: 6. < ϕ + 15 N < 7.4 where φ [mm] represents a diameter of a circumscribed circle in the main scanning cross section of the deflecting unit, and N represents a number of deflecting surfaces of the deflecting unit. ### Claim 13 (depends on 1) The light scanning apparatus according to claim 1, wherein a following condition is satisfied: 22.6 < Y max + ( ϕ N ) < 37. where φ represents a diameter of a circumscribed circle in the main scanning cross section of the deflecting unit, N represents a number of deflecting surfaces of the deflecting unit, and Ymax+ represents a distance in the main scanning direction between an on-axis image height and an outermost off-axis image height on a side on which the light source is arranged on the surface to be scanned. ### Claim 14 (depends on 1) The light scanning apparatus according to claim 1, wherein a following condition is satisfied: 1.78 < θ i + θ max + θ BD < 2.33 where θi represents an angle formed by a traveling direction of a principal ray of the light flux immediately before being incident on the deflecting unit with respect to an optical axis of the first optical system in the main scanning cross section, θmax+ represents an angle formed by the traveling direction of the principal ray of the light flux traveling to an outermost off-axis image height on a side on which the light source is arranged immediately after being deflected by the deflecting unit with respect to the optical axis of the first optical system in the main scanning cross section, and θBD represents an angle formed by the traveling direction of the principal ray of the light flux traveling to a center of a light receiving surface of a light receiving element immediately after being deflected by the deflecting unit with respect to the optical axis of the first optical system in the main scanning cross section. ### Claim 15 (depends on 1) The light scanning apparatus according to claim 1, wherein the first optical system is formed by a single optical element, and wherein a following condition is satisfied: 0.23 < θ BD + θ max + ( 360 N ) < 0.35 where θmax+ [°] represents an angle formed by a traveling direction of a principal ray of the light flux traveling to an outermost off-axis image height on a side on which the light source is arranged immediately after being deflected by the deflecting unit with respect to an optical axis of the first optical system in the main scanning cross section, θBD [°] represents an angle formed by the traveling direction of the principal ray of the light flux traveling to a center of a light receiving surface of a light receiving element immediately after being deflected by the deflecting unit with respect to the optical axis of the first optical system in the main scanning cross section, and N represents a number of deflecting surfaces of the deflecting unit. ### Claim 16 (depends on 1) The light scanning apparatus according to claim 1, wherein the first optical system is formed by a plurality of optical elements, wherein the part of the light flux deflected by the first deflecting surface at the first angle is received by a light receiving element without passing through the first optical system, and wherein a following condition is satisfied: 360 N - 45 < θ BD - θ max + < ( 360 N ) 2 where θmax+ [°] represents an angle formed by a traveling direction of a principal ray of the light flux traveling to an outermost off-axis image height on a side on which the light source is arranged immediately after being deflected by the deflecting unit with respect to an optical axis of the first optical system in the main scanning cross section, θBD [°] represents an angle formed by the traveling direction of the principal ray of the light flux traveling to a center of a light receiving surface of the light receiving element immediately after being deflected by the deflecting unit with respect to the optical axis of the first optical system in the main scanning cross section, and N represents a number of deflecting surfaces of the deflecting unit. ### Claim 17 (depends on 1) The light scanning apparatus according to claim 1, wherein the first optical system is formed by a plurality of optical elements, wherein the part of the light flux deflected by the first deflecting surface at the first angle is received by a light receiving element after passing through at least one optical element included in the first optical system, and wherein a following condition is satisfied: 0.145 < θ BD + θ max + ( 360 N ) < 0.182 where θmax+ [°] represents an angle formed by a traveling direction of a principal ray of the light flux traveling to an outermost off-axis image height on a side on which the light source is arranged immediately after being deflected by the deflecting unit with respect to an optical axis of the first optical system in the main scanning cross section, θBD [°] represents an angle formed by the traveling direction of the principal ray of the light flux traveling to a center of a light receiving surface of the light receiving element immediately after being deflected by the deflecting unit with respect to the optical axis of the first optical system in the main scanning cross section, and N represents a number of deflecting surfaces of the deflecting unit. ### Claim 18 (depends on 1) The light scanning apparatus according to claim 1, wherein a following condition is satisfied: W BD < W max - < W max + where WBD represents a width of the light flux deflected by the first deflecting surface and then travels to a center of a light receiving surface of a light receiving element in the main scanning cross section, Wmax+ represents a width of the light flux deflected by the first deflecting surface and then travels to an outermost off-axis image height on a side on which the light source is arranged in the main scanning cross section, and Wmax− represents a width of the light flux deflected by the first deflecting surface and then travels to an outermost off-axis image height on a side opposite to the side on which the light source is arranged in the main scanning cross section. ### Claim 19 (depends on 1) The light scanning apparatus according to claim 1, wherein a following condition is satisfied: 47. ≤ θ max + ≤ 57. where θmax+ [°] an angle formed by a traveling direction of a principal ray of the light flux traveling to an outermost off-axis image height on a side on which the light source is arranged immediately after being deflected by the deflecting unit with respect to an optical axis of the first optical system in the main scanning cross section. ### Claim 20 (depends on 1) An image forming apparatus, comprising: the light scanning apparatus according to claim 1; and a developing unit configured to develop an electrostatic latent image formed on a surface to be scanned by the light scanning apparatus.