JPH06308410A - Light deflector - Google Patents

Abstract

PURPOSE:To improve soundproofing property and dustproofing property by making the area of the aperture part of a cover as small as possible. CONSTITUTION:The cover having a cylindrical part covering the outside circumference of a rotary polygon mirror 1 is provided. On the cylindrical wall 2a of the cylindrical part, an incident window 4 where illumination light is made incident and the aperture part 3 from which the illumination light deflected to perform scanning by the mirror 1 is emitted are individually provided. The aperture angle (alpha) of the aperture part 3 is set to be a little large angle so that the emission of the emitted illumination light having a viewing angle (theta) is not obstructed. The window 4 is constituted of a member consisting of a transparent glass or a plastic, etc., and where the illumination light is transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflector for deflecting and scanning a laser beam or the like at a high speed in a laser printer or the like.

[0002]

2. Description of the Related Art Optical deflectors for laser printers, laser facsimiles and the like have been particularly accelerated in recent years, and rotary polygon mirrors used for these deflectors rotate at high speeds of 10,000 or more revolutions per minute. When the rotary polygon mirror is rotated at such a high speed, the wind noise during rotation is increased and a large noise is generated. Therefore, the periphery of the rotary polygon mirror is covered with a substantially cylindrical cover.

FIG. 4 illustrates a general optical deflector as a whole. A laser oscillator 1 mounted on an optical box 100 is shown.
The laser light L ₀ generated from 10 is condensed into a predetermined beam shape by the cylindrical lens 105,
It is deflected and scanned by the rotary polygon mirror 101, and an image is formed on the photosensitive drum 107 via the imaging lens system 106. A part of the laser light reflected by the rotary polygon mirror 101 is introduced into the optical fiber 109 by the reflection mirror 108 and converted into a scanning start signal.

FIG. 5 shows the rotary polygon mirror 101 and its drive unit. The drive unit of the rotary polygon mirror 101 is a rotary shaft 111.
And the rotor magnet 112 integrally connected to the
The rotary polygon mirror 1 includes a stator coil 114 that is integral with a bearing device 113 that supports the rotary shaft 111, and a circuit board 115 that supplies a drive current to the stator coil 114.
01 is a corrugated washer 116a and a flat washer 116b
A pressing mechanism 116 including a stopper ring 116c presses the flange member 111a, which is integrated with the rotating shaft 111, and thereby is integrated with the rotating shaft 111. The rotary polygon mirror 101 is covered with a substantially cylindrical cover 102, which limits the flow of air accompanying the rotation of the rotary polygon mirror 101, reduces wind noise, and reduces wind noise. To prevent leakage. The cover 10
The second cylindrical portion 102a has a window 10 through which laser light passes.
3 is provided.

[0005]

However, in the above-mentioned conventional technique, since the laser light is made incident and emitted by one window which is an opening provided in the cylindrical portion of the cover, the opening area of the window is predetermined. There is an unsolved problem that the size must be equal to or larger than that, and there is a limitation in improving the soundproofing and dustproofing effects.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and an optical deflector in which the opening area of the opening of the cover is made as small as possible to improve the soundproofness and the dustproofness. The purpose is to realize.

[0007]

In order to achieve the above object, an optical deflector of the present invention comprises a rotary polygon mirror for deflecting and scanning the illumination light radiated to the outer peripheral surface thereof, and a cylindrical portion covering the outer periphery thereof. A cover having a cover, and an entrance window through which the illumination light enters and an opening through which the illumination light exits are separately provided on the cylindrical wall of the cylindrical portion, and the entrance window transmits the illumination light. It is characterized by consisting of.

Further, a cylindrical body having a free end side that surrounds the opening is opened is projected from the cylindrical wall, and it is effective to provide an entrance window in the cylindrical body.

Further, the entrance window also serves as a diaphragm.

[0010]

The area of the opening through which the illumination light exits is only required to emit the scanning light deflectively scanned at a predetermined scanning angle, and does not require a space for the incident illumination light. The opening area of the opening can be made smaller than that of the conventional example.

Further, if a cylindrical body having a free end side that surrounds the periphery of the opening is provided so as to project from the cylindrical wall of the cylindrical portion, soundproofness and dustproofness are further improved.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing the main part of the first embodiment.

The optical deflector of this embodiment is provided with a rotary polygon mirror 1 which is rotated at a high speed by a driving mechanism (not shown) and a cover 2 having a cylindrical portion covering the outer periphery thereof, and a cylindrical wall 2a of the cylindrical portion. The incident window 4 through which the laser light, which is the illumination light emitted from the semiconductor laser 5, becomes parallel light flux L ₁ by the collimator lens 6 and is incident, and the rotary polygon mirror 1.
Each of the openings 3 is provided to emit the illumination light which is deflected and scanned by the reflection surface 1a which is the outer peripheral surface and is imaged on the photosensitive drum through an imaging lens system (not shown).
The flange portion 2c of the cover 2 is fixed to a circuit board of a motor that drives a rotary polygon mirror (not shown) by inserting a screw into the fixing hole 2d.

In the present embodiment, the opening angle α of the opening 3 is set to be slightly larger than the angle of view θ of the illumination light deflectively scanned, while the entrance window 4 is made of transparent glass or plastic. It is composed of a member that transmits the illumination light.

In this embodiment, the opening angle α of the opening 3 can be made small within a range that does not hinder the emission of the deflected and scanned illumination light having the angle of view θ, and a space for incident illumination light is provided. Since it is not necessary, the opening area of the opening 3 can be made smaller than that of the conventional example. As a result, soundproofing and dustproofing are improved.

FIG. 2 is a schematic perspective view showing the main part of the second embodiment.

This embodiment is provided with an entrance window 14 which also serves as a diaphragm in place of the entrance window 4 of the first embodiment, and since the other portions are the same as those of the first embodiment, the first embodiment The same parts as those in the example are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described.

The diameter of the entrance window 14 of this embodiment is smaller than the diameter of the parallel light flux L _{1 which} is collimated by the collimator lens 6 (see FIG. 1). As a result, the entrance window 14 also serves as a diaphragm.

FIG. 3 is a schematic perspective view showing the main part of the third embodiment.

In this embodiment, the cylindrical wall 2a of the first embodiment is provided with a cylindrical body 27 projecting from the free end side which surrounds the periphery of the opening 3, and is similar to the first embodiment. The parts are indicated by the same reference numerals and the description thereof is omitted, and the part different from the first embodiment will be mainly described.

The cylindrical body 27 of the present embodiment is provided on the cylindrical wall 2a so as to surround the periphery of an opening (not shown) similar to that of the first embodiment, and both sides of the opening in the circumferential direction. Guide walls 27a and 27b are provided so as to project in opposite directions from each other along the tangential plane of the cylindrical wall 2a, and one of the guide walls 27a is provided with an entrance window 24.
The aperture of the entrance window 24 of this embodiment may be a window which also serves as the aperture as in the second embodiment.

In this embodiment, the air in the cover flows out from the open portion 29 of the cylindrical body 27 that is farther away from the rotating polygon mirror, so that the wind noise of the rotating polygon mirror is prevented from leaking to the outside. It is possible to improve the soundproofing.

In the above embodiments, the cover 2 is attached to the circuit board of the motor, but the same effect can be expected if the cover is integrally provided with the lid portion that substantially seals the inside of the optical box.

[0025]

Since the present invention is configured as described above, it has the following effects.

The opening area of the opening can be reduced within a range that does not hinder the emission of the deflected and scanned illumination light to reduce the outflow and inflow of air in the cover.
As a result, the wind noise of the rotary polygon mirror can be prevented from leaking to the outside, so that the soundproofing property is improved, and the intrusion of dust from the outside is reduced to improve the dustproof property.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a main part of a first embodiment.

FIG. 2 is a schematic perspective view showing a main part of a second embodiment.

FIG. 3 is a schematic perspective view showing a main part of a third embodiment.

FIG. 4 is an explanatory diagram showing an entire conventional optical deflector.

FIG. 5 is a partial schematic cross-sectional view showing a rotary polygonal mirror of a conventional optical deflector and its drive unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating polygon mirror 2 cover 2a cylindrical wall 2b top wall 2c flange 2d fixing hole 3 opening 4, 14, 24 entrance window 5 semiconductor laser 6 collimator lens

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taku Butada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Noboru Nabeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Hideyuki Miyamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (3)

[Claims] 1. A rotary polygonal mirror for deflecting and scanning illumination light applied to an outer peripheral surface thereof, and a cover having a cylindrical portion covering the outer periphery thereof, wherein the illumination light is incident on a cylindrical wall of the cylindrical portion. An optical deflector, wherein a window and an opening through which the illumination light is emitted are provided separately, and the incident window is made of a member that transmits the illumination light. 2. The cylindrical body is provided with a cylindrical body projecting from the free end side that surrounds the periphery of the opening, and the cylindrical body is provided with an entrance window. Light deflector. 3. The optical deflector according to claim 1, wherein the entrance window also serves as a diaphragm.