Image forming apparatus with laser scanning components positioned for enhanced compactness

Patent metadata

Field	Value
Publication number	US-12498649-B2
Application number	US-202318496765-A
Country	US
Kind code	B2
Filing date	Oct 27, 2023
Priority date	Oct 1, 2018
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

An image forming apparatus includes a plurality of photosensitive members; a scanner unit including light sources, a rotatable polygonal mirror, and reflecting members; and a fixing portion. Parts of the laser beams emitted from the light sources are reflected by the rotatable polygonal mirror toward the fixing device side, and rest parts of the laser beams are reflected by the rotatable polygonal mirror toward a side opposite from the fixing device side. Of the parts of the laser beams reflected by the rotatable polygonal mirror toward the fixing device side, the laser beam reflected toward the reflecting member provided at a position remotest from the rotatable polygonal mirror travels downward relative to a horizontal direction. A rotational axis of the rotatable polygonal mirror is inclined relative to a vertical direction.

First claim

What is claimed is:

1 . An image forming apparatus comprising:
a plurality of photosensitive members; a scanner unit configured to scan said photosensitive members with laser beams in accordance with image information, wherein said scanner unit includes light sources corresponding to said photosensitive members, respectively, a rotatable polygonal mirror configured to reflect and deflect the laser beams emitted from said light sources, a frame configured to support said rotatable polygonal mirror, a plurality of reflecting members configured to reflect the laser beams, respectively, reflected by said rotatable polygonal mirror, and a cover configured to cover an opening of said frame, wherein said cover is provided with passing portions through which the laser beams pass to an exterior of the scanner unit; and a fixing device configured to fix, on a recording material, toner images formed on said photosensitive members and then superposed on the recording material, wherein with respect to a vertical direction, said scanner unit is located above said photosensitive members, wherein selected ones of the laser beams emitted from said light sources are reflected by said rotatable polygonal mirror toward a side where said fixing device is provided, and remaining ones of the laser beams are reflected by said rotatable polygonal mirror toward a side opposite from the side where said fixing device is provided, wherein of the selected ones of the laser beams reflected by said rotatable polygonal mirror toward the side where said fixing device is provided, and with respect to a first reflecting member provided at a position remotest from said rotatable polygonal mirror toward the side where said fixing device is provided among said plurality of reflecting members, the laser beam reflected toward the first reflecting member travels downward relative to an imaginary line connecting rotational axes of said photosensitive members as seen in a rotational axis direction of one of said photosensitive members, wherein of the remaining ones of the light beams, and with respect to a second reflecting member provided at a position remotest from said rotatable polygonal mirror toward the side opposite from the side where said fixing device is provided among said plurality of reflecting members, the light beam reflected toward the second reflecting member travels upward relative to the imaginary line as seen in the rotational axis direction, wherein a rotational axis of said rotatable polygonal mirror is supported by said frame at a supporting portion of said frame, wherein with respect to the vertical direction, said cover is located between said supporting portion of said frame and said plurality of photosensitive members, wherein with respect to the vertical direction, said supporting portion of said frame, said rotatable polygonal mirror, said cover, and said plurality of photosensitive members are arranged in this order, and wherein an optical path length from said rotatable polygonal mirror to said first reflecting member is longer than an optical path length from said rotatable polygonal mirror to said second reflecting member.

2 . An image forming apparatus according to claim 1 , further comprising a discharge tray having an inclined surface for receiving the recording material on which an image is formed and which is discharged from an inside of said image forming apparatus,
wherein said scanner unit overlaps with said inclined surface as seen in the vertical direction.

3 . An image forming apparatus according to claim 1 , wherein optical path lengths from said rotatable polygonal mirror to respective photosensitive members are equal to each other.

Assignees

• Canon Kk

Inventors

• Nagatoshi Jun

Classifications

• G03G15/04036

  Details of illuminating systems, e.g. lamps, reflectors (lamp housings for copying cameras, reflex exposure lighting G03B27/542) · CPC title

• G03G2215/0404

  Laser · CPC title

• G03G15/0194

  primary transfer to the final recording medium (G03G15/0184 takes precedence) · CPC title

• G03G2215/0103

  Plural electrographic recording members · CPC title

• G03G15/6552

  Means for discharging uncollated sheet copy material, e.g. discharging rollers, exit trays · CPC title