Optical scanning apparatus and image forming apparatus

Patent metadata

Field	Value
Publication number	US-11726316-B2
Application number	US-202016925986-A
Country	US
Kind code	B2
Filing date	Jul 10, 2020
Priority date	Jul 31, 2019
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

An optical scanning apparatus includes first and second light sources, a rotatable polygonal mirror, a motor, first and second mirrors, first and second lenses, and a casing. Within a mounting range, a top wall of an accommodating portion is provided with at least one projection projecting toward an opening of the accommodating portion. The projection extends from a first side wall to a second side wall of the accommodating portion. The top wall includes a recess formed opposite from the projection, and is free from a portion projecting toward the opening over a range from the first side wall to the second side wall, other than the projection in the mounting range. A free end portion of the projection is in a position remoter from the opening than a reflecting surface of the rotatable polygonal mirror is with respect to a rotational axis direction of the motor.

First claim

What is claimed is:

1. An optical scanning apparatus comprising:
a first light source;
a second light source;
a rotatable polygonal mirror configured to reflect and deflect first laser light emitted from said first light source and second laser light emitted from said second light source, said rotatable polygonal mirror reflecting the second laser light in a direction opposite to a reflection direction of the first laser light;
a motor configured to rotationally drive said rotatable polygonal mirror;
a first mirror configured to reflect the first laser light deflected by said rotatable polygonal mirror and configured to guide the reflected first laser light to a first surface-to-be-scanned;
a second mirror configured to reflect the second laser light deflected by said rotatable polygonal mirror and configured to guide the reflected second laser light to a second surface-to-be-scanned;
a first lens configured to image the first laser light deflected by said rotatable polygonal mirror on said first surface-to-be-scanned;
a second lens configured to image the second laser light deflected by said rotatable polygonal mirror on said second surface-to-be-scanned; and
a casing accommodating said rotatable polygonal mirror, said motor, said first and second mirrors and said first and second lenses, wherein said casing includes an accommodating portion including a top wall provided with a mounting surface on which said motor is mounted, a first side wall opposing one end portion of said first lens with respect to a longitudinal direction of said first lens, a second side wall opposing the other end portion of said first lens with respect to the longitudinal direction, and an opening, and includes a cover portion configured to cover said opening, of said accommodating portion, provided at a position opposing said mounting surface,
wherein in a mounting range of said top wall of said accommodating portion in which said motor, said first and second mirrors and said first and second lenses are mounted with respect to a perpendicular direction perpendicular to both a rotational axis direction of said motor and the longitudinal direction of said first lens, at least one projection having a shape such that a part of said top wall projects so that said mounting surface approaches said opening is provided,
wherein said projection extends from said first side wall to said second side wall,
wherein said top wall includes a recess on a surface opposite from said mounting surface at a portion corresponding to said projection,
wherein said top wall is free from a portion projecting toward said opening over a range from said first side wall to said second side wall, other than said projection in said mounting range,
wherein with respect to the rotational axis direction, a top end portion of said projection on an opening side of said casing, a reflecting surface of said rotatable polygonal mirror, and the opening of said casing, are arranged in this order, and
wherein the casing is made of resin.

2. An optical scanning apparatus according to claim 1 , further comprising a third light source emitting third laser light reflected by the rotatable polygonal mirror and a fourth light source emitting fourth laser light reflected by the rotatable polygonal mirror,
wherein of the first to fourth laser lights, the first laser light and the second laser light are beams of laser light emitted from said optical scanning apparatus at positions farthest from the rotational polygonal mirror with respect to the direction perpendicular to the rotational axis direction and the longitudinal direction.

3. An optical scanning apparatus according to claim 1 , wherein said recess is provided with a plurality of ribs each emitting in the perpendicular direction.

4. An optical scanning apparatus according to claim 1 , wherein at least a part of said first and second side walls has a double wall structure.

5. An image forming apparatus for forming an image on a sheet, comprising:
a first photosensitive member;
a second photosensitive member;
an optical scanning unit configured to scan said first photosensitive member and said second photosensitive member with first laser light and second laser light, respectively, depending on image information;
first and second developing units configured to position electrostatic latent images, formed on said first and second photosensitive members by said optical scanning unit, with toner; and
a transfer unit configured to transfer first and second toner images formed by developing the electrostatic latent images by said first and second developing units,
wherein said optical scanning unit includes:
a first light source;
a second light source;
a rotatable polygonal mirror configured to reflect and deflect first laser light emitted from said first light source and second laser light emitted from said second light source, said rotatable polygonal mirror reflecting the second laser light in a direction opposite to a reflection direction of the first laser light;
a motor configured to rotationally drive said rotatable polygonal mirror;
a first mirror configured to reflect the first laser light deflected by said rotatable polygonal mirror and configured to guide the reflected first laser light to said first photosensitive member;
a second mirror configured to reflect the second laser light deflected by said rotatable polygonal mirror and configured to guide the reflected second laser light to said second photosensitive member;
a first lens configured to image the first laser light deflected by said rotatable polygonal mirror on said first photosensitive member;
a second lens configured to image the second laser light deflected by said rotatable polygonal mirror on said second photosensitive member; and
a casing accommodating said rotatable polygonal mirror, said motor, said first and second mirrors and said first and second lenses, wherein said casing includes an accommodating portion including a top wall on which said motor is mounted, a first side wall opposing one end portion of said first lens with respect to a longitudinal direction of said first lens, a second side wall opposing the other end portion of said first lens with respect to the longitudinal direction, and an opening, and includes a cover portion configured to cover said opening, of said accommodating portion, provided at a position opposing a motor mounting surface of said top wall,
wherein in a mounting range of said top wall of said accommodating portion in which said motor, said first and second mirrors and said first and second lenses are mounted with respect to a perpendicular direction perpendicular to both a rotational axis direction of said motor and the longitudinal direction of said first lens, at least one projection having a shape such that a part of said top wall projects so that said mounting surface approaches said opening is provided,
wherein said projection is provided over a range from said first side wall to said second side wall,
wherein said top wall includes a recess on a surface opposite from said mounting surface at a portion corresponding to said projection,
wherein said top wall is free from a portion projecting toward said opening over the range from said first side wall to said second side wall, other than said projection in said mounting range,
wherein with respect to the rotational axis direction, a top end portion of said projection on an opening side of said casing, a reflecting surface of said rotatable polygonal mirror, and the opening of said casing, are arranged in this order, and
wherein the casing is made of resin.

Assignees

• Canon Kk

Inventors

• Sano Atsushi
• Nagatoshi Jun

Classifications

• G02B26/122 Primary

  Control of the scanning speed of the polygonal mirror · CPC title

• G02B26/105

  with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence) · CPC title

• G03G15/305 Primary

  with special means to synchronize the scanning optic to the operation of other parts of the machine, e.g. photoreceptor, copy paper · CPC title

• G03G15/50

  Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control (sequencing control G03G21/14) · CPC title

• G02B26/12

  using multifaceted mirrors · CPC title