Polygon mirror, image forming apparatus, and method for manufacturing a polygon mirror
First Claim
1. A polygon mirror made of plastic, the polygon mirror having a plurality of reflecting surfaces, and a first surface intersecting the plurality of reflecting surfaces at a first side, a second surface intersecting the plurality of reflecting surfaces at a second side opposite to the first side, the second surface facing away from the first surface, with a through hole provided to extend through the first surface and the second surface at a center of the polygon mirror, the polygon mirror comprising:
- a plurality of gate marks of injection molding, wherein the gate marks are located on straight lines passing through the center and vertices of the first surface, and are rotationally symmetric with respect to the center, when viewed from an extending direction of the through hole.
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Accused Products
Abstract
A polygon mirror made of plastic is provided. The polygon mirror has a plurality of reflecting surfaces, a first surface intersecting the plurality of reflecting surfaces at a first side, a second surface intersecting the plurality of reflecting surfaces at a second side opposite to the first side, with a through hole provided to extend through the first surface and the second surface at a center of the polygon mirror. The polygon mirror includes a plurality of gate marks of injection molding. When viewed from an extending direction of the through hole, the gate marks are located on straight lines passing through the center and vertices of the first surface, and are rotationally symmetric with respect to the center.
11 Citations
20 Claims
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1. A polygon mirror made of plastic, the polygon mirror having a plurality of reflecting surfaces, and a first surface intersecting the plurality of reflecting surfaces at a first side, a second surface intersecting the plurality of reflecting surfaces at a second side opposite to the first side, the second surface facing away from the first surface, with a through hole provided to extend through the first surface and the second surface at a center of the polygon mirror, the polygon mirror comprising:
a plurality of gate marks of injection molding, wherein the gate marks are located on straight lines passing through the center and vertices of the first surface, and are rotationally symmetric with respect to the center, when viewed from an extending direction of the through hole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An image forming apparatus comprising:
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a light source configured to emit a light beam; a polygon mirror made of plastic, and configured to reflect the light beam emitted by the light source; a motor comprising a rotary shaft configured to rotate about a rotation axis; and a scanning optical system configured to focus the light beam reflected by the polygon mirror on an image surface, wherein the polygon mirror has a plurality of reflecting surfaces, a first surface intersecting the plurality of reflecting surfaces at a first side, and a second surface intersecting the plurality of reflecting surfaces at a second side opposite to the first side, the second surface facing away from the first surface, with a through hole provided to extend through the first surface and the second surface at a center of the polygon mirror, the through hole being configured to be coupled to the rotary shaft, wherein the polygon mirror comprises a plurality of gate marks of injection molding, and wherein when viewed from a direction of the rotation axis, the gate marks are located on straight lines passing through the center and vertices of the first surface, and are rotationally symmetric with respect to the center.
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13. A method for manufacturing a polygon mirror made of plastic, the polygon mirror having a plurality of reflecting surfaces, a first surface intersecting the plurality of reflecting surfaces at a first side, and a second surface intersecting the plurality of reflecting surfaces at a second side opposite to the first side, the second surface facing away from the first surface, with a through hole provided to extend through the first surface and the second surface at a center of the polygon mirror, the method comprising:
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providing a mold having a mold surface defining a cavity contoured to form a shape of the polygon mirror and a plurality of gates for injecting molten plastic therethrough into the cavity; and molding the polygon mirror by injecting the molten plastic through the plurality of gates into the cavity, wherein the plurality of gates are provided such that when viewed from an extending direction of the through hole of the polygon mirror to be molded, the gates are located on straight lines passing through the center and vertices of the first surface, and are rotationally symmetric with respect to the center. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification