JPH1020231A - Optical deflection scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of air flowing inside a cover. SOLUTION: A rotating polygon mirror 24 is held by a driving motor 30, and the mirror 24 and the motor 30 are covered by the cover 31. An aperture 33 through which laser light beams L1 and L2 are made incident on and emitted from the mirror 24 is provided on the main body part 32 of the cover 31, and a cylindrical part 34 through which the laser light beams L1 and L2 are made incident on and emitted from the aperture 33 is provided on the aperture 33. Control boards 35 and 36 controlling the amount of air flowing inside the part 32 are respectively provided above and below the inside surface of the part 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an image forming apparatus such as a laser printer, a copying machine, a laser facsimile, etc., and applies a light beam to a rotary polygon mirror from a cylindrical portion of a cover covering the rotary polygon mirror. The present invention relates to a light deflection scanning device for emitting light.

[0002]

2. Description of the Related Art In recent years, in order to accelerate the speed of this type of light deflection scanning apparatus, a rotating polygon mirror is driven at a speed of one minute by a drive motor.
In many cases, high-speed rotation is performed at several thousand rotations or more. In this case, noise such as wind noise caused by high-speed rotation of the rotary polygon mirror is increased. Therefore, the periphery of the rotary polygon mirror and the drive motor are covered with a cover to prevent noise leakage.

The rotary polygon mirror, the drive motor and the cover are constructed as shown in FIG. 11, for example. A rotary shaft 2 is held by a holding portion 1a of an optical box 1 via a bearing 3, and is attached to the rotary shaft 2. Has a flange 4 fixed thereto. A yoke 5 is fixed to the outer periphery of the flange 4, and a plurality of magnets 6 are fixed to a lower surface of the outer periphery of the yoke 5. A circuit board 7 is fixed to the optical box 1, and a stator coil 8 is arranged on the circuit board 7 so as to face the magnet 6.

A rotary polygon mirror 9 is mounted on the upper surface of the flange 4, and is fixed between the rotary shaft 2 and a fixing member 10. Around the rotating polygon mirror 9, the light beam is
Cover 11 having an opening 11a for entering and exiting from the surface
To restrict the flow of air and prevent wind noise from leaking.

[0005]

In recent years, this type of cover 11 cannot sufficiently prevent noise from leaking.
2. A cover 12 as shown in FIG. 13 has been developed.
In the cover 12, a cylindrical portion 15 having a fan-shaped spread is provided in an opening 14 formed in a cylindrical main body portion 13, so that leakage of noise to the outside is prevented.

However, in the conventional examples shown in FIGS. 12 and 13 described above, since the air violently flows into and out of the cover 12 from the tubular portion 15, the amount of dust adhering to the rotary polygon mirror 9 increases. There is a problem that the performance is deteriorated.

An object of the present invention is to provide an optical deflection scanning apparatus which solves the above-mentioned problems and reduces the amount of dust adhering to a rotary polygon mirror.

[0008]

According to a first aspect of the present invention, there is provided an optical deflection scanning apparatus, comprising: a rotary polygon mirror for deflecting and scanning a light beam covered by a cover; In the light deflection scanning device for causing a beam to enter and exit from the rotary polygon mirror, the cover includes a cylindrical portion that allows a light beam to enter and exit the opening, and the amount of air flowing into the cover into the cylindrical portion. A regulating plate for regulating the pressure is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 shows a first embodiment. At a predetermined position of an optical box 21, a laser unit 22 for emitting a laser beam L1 carrying information and the like is attached. Laser light L1 from laser unit 22
In the traveling direction, a cylindrical lens 23 for converting the laser light L1 into linear light and a rotary polygon mirror 24 for deflecting and scanning the laser light L1 are sequentially arranged.

In the direction in which most of the laser light L2 deflected and scanned by the rotary polygon mirror 24 travels, the spherical lens 2
5, a toric lens 26 and a photosensitive drum 27 are sequentially arranged. A light detection mirror 28 is disposed in a direction in which a part of the laser light L3 deflected by the rotary polygon mirror 24 travels, and a light detector 29 is disposed in a reflection direction of the light detection mirror 28. And the photodetector 29
Is connected to the control means via an optical fiber (not shown), and is used to determine the scanning start position of the laser light L1 emitted from the laser unit 22.

As shown in FIG. 2 and FIG.
Is supported by a drive motor 30 having a substrate 30a,
The rotating polygon mirror 24 and the drive motor 30 are covered by a cover 31. The cover 31 is divided into an upper cover 31a and a lower cover 31b as shown in FIG.
Are fixed by bonding, heat caulking, welding or the like.

The cover 31 is provided with a cylindrical main body 32 for covering the rotary polygon mirror 24 and the drive motor 30. The main body 32 has a wide opening 33 through which laser light enters and exits the rotary polygon mirror 24. The opening 33 is provided with a cylindrical portion 34 extending in a fan shape outward. A regulating plate 3 for regulating the amount of air flowing into the main body 32 is provided at the upper and lower positions on the inner surface of the cylindrical portion 34.
5 and 36 are provided respectively.

The laser light L1 emitted from the laser unit 22 is condensed linearly by the cylindrical lens 23, and is regulated from the cylindrical portion 34 of the cover 31 to the regulating plates 35, 36.
And through the opening 33 to enter the rotary polygon mirror 24. Laser beam L2 deflected and scanned by rotating polygon mirror 24
Passes through the opening 33 and between the regulating plates 35 and 36, exits from the cylindrical portion 34, passes through the spherical lens 25 and the toric lens 26, and enters the photosensitive drum 27.

At this time, as shown in FIG.
4 rotates in the direction A, the air flows as indicated by the dotted line, and a part of the air flowing into the cylindrical portion 34 from the direction B flows in the direction C along the inner surface of the main body 32 as a whole. At the same time, it flows in the direction D and flows out of the cylindrical portion 34. The remainder of the air that has flowed into the cylindrical portion 34 flows along the regulating plates 35 and 36 as shown in the direction E, and flows out of the cylindrical portion 34 without contacting the rotating polygon mirror 24. The air flowing in the direction D so as to flow out of the cylindrical portion 34 flows in the direction F so as to come into contact with the regulating plates 35 and 36 and return into the main body 32.

As described above, in the first embodiment, the regulating plate 3
The provision of 5 and 36 makes it possible to regulate the amount of air flowing into the main body 32 of the cover 31 and to prevent the rotating polygon mirror 24 from being stained, thereby preventing performance degradation.

FIGS. 5 and 6 show a second embodiment. A cover 41 is provided with a main body 42, an opening 43 and a cylindrical portion 44 similar to those of the first embodiment. Inside regulating plates 45 and 46 are provided on the rotating polygon mirror 24 side above and below, respectively, and outside regulating plates 47 and 48 are attached to the rotating polygon mirror 2.
4 are provided outside.

Here, the laser beam L1 incident on the rotary polygon mirror 24 is condensed linearly in the direction X by the cylindrical lens 23, and the reflected light L2 from the rotary polygon mirror 24 leaves the rotary polygon mirror 24. The height of the inner regulating plates 45 and 46 is set to
It is made larger than the height of 7,48. At this time, the upper and lower widths of the laser light L1 are 0.1 to 0.
Considering that it is about 2 mm, the inner regulating plates 45, 4
It is preferable that the height of each of the outer control plates 6 and the outer control plates 47 and 48 be as large as possible.

In the second embodiment, the amount of air flowing in the direction F is made larger than that in the first embodiment, and
The amount of air flowing into the
The dirt of the rotary polygon mirror 24 can be prevented more than the embodiment. If more regulating plates are provided in addition to the inner regulating plates 45 and 46 and the outer regulating plates 47 and 48, the amount of air flowing into the main body 42 can be regulated more. Further, the cover 41 can be divided and formed as in the first embodiment.

FIGS. 7 and 8 show a third embodiment. A cover 51 is provided with a main body 52, an opening 53 and a tubular portion 54 similar to those in the first embodiment. The upper and lower sides are provided with regulating plates 55 and 56 which are inclined to the opposite side of the rotary polygon mirror 24, respectively.

In the third embodiment, the regulating plates 55, 56
Is inclined to the opposite side of the rotary polygon mirror 24, so that the amount of air flowing in the direction E can be made larger than that of the first embodiment, and the amount of air flowing into the main body 52 can be made smaller than that of the first embodiment. Can also be reduced. Further, the cover 51 can be divided and formed as in the first embodiment.

FIGS. 9 and 10 show a fourth embodiment. A cover 61 has a main body 62 and an opening 63 similar to those of the first embodiment.
And a cylindrical portion 64 provided above and below the opening 63.
5 and 66 are provided integrally with the main body 62.

In the fourth embodiment, since the amount of air flowing in the direction C in the main body 62 can be increased, the amount of air flowing into and out of the main body 62 can be reduced.
An effect similar to that of the first embodiment can be obtained. Also,
This cover 61 can be formed as one component.

In the first embodiment, the regulating plates 35 and 36 are provided above and below the inner surface of the cylindrical portion 34. However, the regulating plates 35 and 36 may be provided all around or partially on the inner surface. The same can be applied to the embodiment of FIG.

[0024]

As described above, in the light deflection scanning device according to the present invention, the cover is provided with a cylindrical portion for allowing the light beam to enter and exit the opening, and the amount of air flowing into the cover is provided on the inner surface of the cylindrical portion. Since a regulating plate for regulating the air pressure is provided, the amount of air flowing into the cover can be reduced by the regulating plate,
The amount of dust adhering to the rotating polygon mirror can be reduced to prevent performance degradation.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment with a part cut away.

FIG. 2 is a plan view in which a part of a cover is cut away.

FIG. 3 is a side view in which a part of a cover is cut away.

FIG. 4 is an explanatory diagram of a manufacturing method of a cover.

FIG. 5 is a plan view of the cover of the second embodiment with a part of the cover cut away.

FIG. 6 is a partially cutaway side view.

FIG. 7 is a plan view of a cover of the third embodiment with a part cut away.

FIG. 8 is a partially cutaway side view.

FIG. 9 is a plan view of a cover of the fourth embodiment with a part cut away.

FIG. 10 is a partially cutaway side view.

FIG. 11 is a sectional view of a driving unit of a conventional rotary polygon mirror.

FIG. 12 is a plan view of a cover of a conventional example.

FIG. 13 is a side view in which a part of a conventional cover is cut away.

[Description of Signs] 24 rotating polygon mirrors 31, 41, 51, 61 covers 33, 43, 53, 63 openings 34, 44, 54, 64 cylindrical portions 35, 36, 45, 46, 47, 48, 55, 56 , 6
5, 66 regulation plate

Claims (4)

[Claims] A rotating polygon mirror for deflecting and scanning the light beam with a cover, and an optical deflection scanning device for causing the light beam to enter and exit the rotating polygon mirror through an opening formed in the cover; A light deflection scanning device, comprising: a tubular portion for allowing a light beam to enter and exit the opening; and a regulating plate for regulating the amount of air flowing into the cover in the tubular portion. 2. The optical deflection scanning apparatus according to claim 1, wherein the number of the regulating plates is plural, and the height of the regulating plate on the side of the rotary polygon mirror is larger than the heights of the other regulating plates. 3. The optical deflection scanning device according to claim 1, wherein the regulating plate is inclined to a side opposite to the rotary hand mirror. 4. The light deflection scanning device according to claim 1, wherein said regulating plate is provided at said opening position.