JP2002350768A - Laser scanner and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser scanner capable of realizing the reduction of parts cost and assembly cost and an image forming device capable of realizing the reduction of costs, and to provide the laser scanner and the image forming device capable of decreasing noise and vibration. SOLUTION: A polygon mirror 14 is housed inside a housing 5. The housing 5 includes an upper cover and a bottom board 4 opposed up and down, and outer peripheral wall 6 erected from the periphery part of the board 4 and covering over the side. An inner peripheral wall 7 is provided to cover over the side of the mirror 14 between the mirror 14 and the wall 6. A part of the wall 7 is provided to be extended to the wall 6 and forms a hermetically sealed space 20 with the wall 6, the board 4 and the cover 3. The board 4, the wall 6 and the wall 7 are made of resin and form a base part 9 where they are integrally molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser scanning device for scanning a laser beam and an image forming apparatus using the same.

[0002]

2. Description of the Related Art A laser beam printer is a typical printer capable of high-speed printing.
A laser beam printer forms an electrostatic latent image on a photoconductor by scanning, for example, a drum-shaped photoconductor with a laser beam using a laser scanning device, and develops the electrostatic latent image with toner to form a visible image. An output image is obtained by forming a toner image and transferring the toner image onto paper.

[0003] The laser scanning device is generally configured such that a laser beam generated and adjusted by a laser diode unit is reflected by a polygon mirror and guided to a photosensitive member. As the polygon mirror rotates at a high speed, the laser beam scans the photoconductor in the length direction of the photoconductor (main scanning direction). Since the polygon mirror is driven by a motor and rotates at high speed, loud noise (wind noise)
Occurs. Conventionally, in order to reduce noise, a polygon mirror has been mounted inside a housing while being housed in a cover having a complicated shape.

[0004]

However, since the number of parts is increased due to the cover, the cost of parts and the cost of assembling the laser scanning device are also high. An image forming apparatus using such a laser scanning device is expensive. In addition, vibration is transmitted from the motor that rotationally drives the polygon mirror to the housing, and the housing sometimes vibrates. An image forming apparatus using such a laser scanning device has high noise and vibration during driving.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser scanning device capable of reducing parts costs and assembly costs. Another object of the present invention is to provide a laser scanning device capable of reducing noise and vibration. Still another object of the present invention is to provide an image forming apparatus capable of reducing costs.

A further object of the present invention is to provide an image forming apparatus capable of reducing noise and vibration.

[0007]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention for solving the above problems, at least a part of the double wall structure (6, 7) forming the closed space (20) is provided. And a housing (5) that is housed inside the housing,
Polygon mirror for scanning laser beam (14)
And a laser scanning device (17). It should be noted that the alphanumeric characters in parentheses indicate corresponding components and the like in the embodiments described later. Hereinafter, the same applies in this section.

[0008] The housing may include a pair of opposing plate members and an outer peripheral wall provided so as to cover the sides thereof. An inner peripheral wall may be provided between the polygon mirror and the outer peripheral wall so as to cover the side of the polygon mirror. In this case, the inner peripheral wall and the outer peripheral wall form a double wall structure. A part of the inner peripheral wall may be extended to the outer peripheral wall. In this case, the enclosed space
It can be formed by an inner peripheral wall, an outer peripheral wall, and a pair of plate-shaped members.

The plate member may have a double wall structure. In this case, a closed space may be formed by providing a partition in the double wall, or a closed space may be formed within the thickness of the plate member by a gas injection molding method. When the inner peripheral wall is provided, the inner peripheral wall has a light entrance opening for allowing a laser beam to pass from the laser diode unit toward the polygon mirror, and a laser beam reflected by the polygon mirror passes through the fθ lens. For light emission may be formed. The housing may have a scanning opening through which the laser beam passes from the laser scanning device toward the external photoconductor, and may include components (eg, a motor for rotating and driving a polygon mirror).
May be formed.

According to the structure of the present invention, the double wall structure of the housing can reduce noise (wind noise) generated when the polygon mirror rotates. That is, the same effect as when the cover is provided on the polygon mirror can be obtained. Furthermore, the noise transmitted to the outside can be effectively reduced by the closed space. A motor for rotationally driving the polygon mirror may also be arranged inside the housing. In this case, noise generated from the motor can also be reduced.

According to a second aspect of the present invention, there is provided the laser scanning device according to the first aspect, wherein the double wall structure is formed integrally with a part of the housing. The housing is
In the case of including a pair of opposing plate members, an outer peripheral wall, and an inner peripheral wall, the outer peripheral wall and the inner peripheral wall can be formed integrally with one of the plate members using, for example, resin. . When the plate-like member has a double wall structure, the plate-like member can be integrally formed by a gas injection molding method using a resin or the like.

In these cases, the number of parts is smaller than when a cover is separately provided. Further, in the assembling process of the laser scanning device, it is not necessary to separately attach an inner peripheral wall or the like to a plate-like member. Therefore, the cost of parts and the cost of assembling the laser scanning device can be reduced. According to a third aspect of the present invention, there is provided an anti-vibration member (11) attached to the housing.
The laser scanning device according to claim 1, further comprising:

The vibration transmitted from the motor for rotating the polygon mirror to the housing can be attenuated by the vibration isolating member. Further, noise generated by rotation of the polygon mirror can be reduced. Furthermore, the vibration isolating member can also prevent the housing from resonating with noise or vibration from a motor that drives the polygon mirror to rotate, and prevent the housing from becoming a secondary noise or vibration source. The vibration isolation member may be attached to the outside of the housing, or may be attached to the inside of the housing. Also, regarding the polygon mirror,
By attaching the vibration isolating member in a direction where the double wall structure is not provided, noise generated by rotation of the polygon mirror can be effectively reduced.

According to a fourth aspect of the present invention, a photoconductor (16) is provided.
An image forming apparatus comprising: a laser scanning device according to any one of claims 1 to 3 for writing an electrostatic latent image on the photosensitive member. Claims 1 to 4
By using the laser scanning device described in any one of the above, the cost of the image forming apparatus can be reduced, and noise and vibration when driving the image forming apparatus can be reduced.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an illustrative plan view showing a part of a laser beam printer according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II. FIGS. 1 and 2 show a laser scanning device 17 for generating and scanning a laser beam, and a photoconductor 16 on which an electrostatic latent image is written by the laser beam.

The laser scanning device 17 includes a laser beam L generated and adjusted by a laser diode unit 18.
Is reflected by the polygon mirror 14, further reflected by the return mirror 1, and guided to the drum-shaped photoconductor 16. When the polygon mirror 14 is rotated at a high speed by the motor 2, the laser beam L scans the photosensitive member 16, which is uniformly charged in advance, in the length direction (main scanning direction) of the photosensitive member 16. The polygon mirror 14 rotates at a constant angular velocity, but the laser beam L scans the photoconductor 16 at a constant velocity by the fθ lenses 13 and 15.

The scanning of the laser beam L is repeated while the photosensitive member 16 rotates around the rotation axis B,
The portion irradiated by the laser beam L also moves in the sub-scanning direction perpendicular to the main scanning direction. As a result, a two-dimensional electrostatic latent image is formed on the peripheral surface of the photoconductor 16. Thereafter, the electrostatic latent image is converted into a toner image by a developing device (not shown), and the toner image is transferred to a sheet and fixed, thereby obtaining an output image.

The laser diode unit 18, the polygon mirror 14, the fθ lenses 13 and 15, and the folding mirror 1 are housed inside the housing 5. The housing 5 is
It includes an upper lid 3 (not shown in FIG. 1) facing vertically, a bottom plate 4, and an outer peripheral wall 6 erected from the periphery of the bottom plate 4 and covering the side. An inner peripheral wall 7 is provided between the polygon mirror 14 and the outer peripheral wall 6 so as to cover the sides of the polygon mirror 14. Part of the inner peripheral wall 7
It extends to the outer peripheral wall 6. Bottom plate 4, outer peripheral wall 6,
The inner peripheral wall 7 is made of resin, and forms a base 9 integrally formed.

On the inner peripheral wall 7, a laser beam L is directed from the laser diode unit 18 to the polygon mirror 14.
And a light exit opening 12 for passing the laser beam L reflected by the polygon mirror 14 toward the fθ lens 13. A sponge 10 as a sealing member made of an elastic material is interposed between the inner peripheral wall 7 and the upper lid 3. Beside the polygon mirror 14, a laser diode unit 18
In the direction where the fθ lenses 13 and 15 are not arranged,
The outer peripheral wall 6 and the inner peripheral wall 7 are close to each other, and together with the bottom plate 4 and the upper lid 3, form a closed space 20.

The motor 2 for rotating and driving the polygon mirror 14 is disposed so as to penetrate the bottom plate 4.
It is fixed to the bottom plate 4 via a mounting plate 19. Between the return mirror 1 and the photoconductor 16, a scanning opening 21 for passing the laser beam L is formed in the bottom plate 4. On the outer side (upper surface) of the upper lid 3, a vibration damping material 11 (FIG. 1)
Are omitted). On the outside (lower surface) of the bottom plate 4, a vibration isolator 11 is attached in a region surrounded by the inner peripheral wall 7 in plan view.

According to the above configuration, the polygon mirror 14
Regarding the above, the inner peripheral wall 7 and the outer peripheral wall 6 are arranged on the side, and the bottom plate 4 or the upper lid 3 to which the vibration damping material 11 is attached exists in a direction where these are not arranged. That is, the polygon mirror 14 is covered with the inner peripheral wall 7, the outer peripheral wall 6, or the vibration isolator 11 in any direction except for the light entrance opening 8, the light exit opening 12, and the motor 2.

As a result, noise (wind noise) generated when the polygon mirror 14 rotates can be reduced. In particular, noise is effectively reduced in the direction in which the closed space 20 is formed. The inner peripheral wall 7 is formed integrally with the bottom plate 4, and a sponge 10 is interposed between the inner peripheral wall 7 and the upper lid 3 to fill the gap. No noise is leaked from.
An image forming apparatus using such a laser scanning device 17 can reduce noise during driving.

Since the inner peripheral wall 7 is formed integrally with the bottom plate 4, the number of parts is smaller than when a cover for the polygon mirror 14 is separately provided. Further, the inner peripheral wall 7 does not need to be separately attached to the bottom plate 4 or the like in the assembly process of the laser scanning device 17. Therefore, the cost of parts and the cost of assembling the laser scanning device can be reduced.
An image forming apparatus using such a laser scanning device 17 can reduce costs.

The vibration isolator 11 can reduce the vibration generated by the motor 2 and transmitted to the housing 5. Furthermore, the vibration-proof material 11 can also prevent the housing 5 from resonating with noise or vibration from the motor 2 and the housing 5 from becoming a secondary noise source or vibration source. Further, by providing the inner peripheral wall 7, the rigidity of the base portion 9 is increased. This can also reduce vibration. An image forming apparatus using such a laser scanning device 17 can reduce vibration during driving.

In the above embodiment, the inner peripheral wall 7 that covers the sides of the polygon mirror 14 includes four substantially flat partition walls, but may have a curved surface such as a cylindrical shape. The upper lid 3 may be made of resin. In this case, the inner peripheral wall 7 and the outer peripheral wall 6 may be formed integrally with the upper lid 3 instead of the bottom plate 4.
In the above embodiments, the bottom plate 4 and the upper lid 3 are single plates, but may have a double wall structure. In this case, noise and vibration can be reduced without attaching the vibration isolator 11. When the bottom plate 4 or the upper lid 3 is made of resin, a double wall structure including a closed space can be integrally formed by a gas injection molding method or the like. By such a manufacturing method, the bottom plate 4 and the upper lid 3 having the double wall structure can be manufactured at low cost. The closed space may be formed by providing a partition in the double wall.

Further, in the above embodiment, a part of the motor 2 is disposed outside the housing 5, but the bottom plate 4 is not provided with a hole, and the whole motor 2 is formed by the bottom plate 4, the top cover 3, and the inside. It may be arranged so as to be surrounded by the peripheral wall 7. In this case, noise generated from the motor 2 can also be reduced. The laser scanning device 17 may generate and scan one laser beam L, or may generate and scan two or more laser beams L. The shape of the photoconductor 16 may be a belt shape or the like. The type of the image forming apparatus may be a copying machine or a facsimile apparatus other than the laser beam printer.

In addition, various design changes can be made within the scope of the matters described in the claims.

[0028]

EXAMPLE Table 1 summarizes the noise levels measured outside the housing 5 in each case by changing the total area of the vibration damping material 11 attached to the bottom plate 4 and the top cover 3.

[0029]

[Table 1]

The noise when the vibration isolator 11 is attached is smaller than that when the vibration isolator 11 is not attached, and the noise becomes smaller as the area where the vibration isolator 11 is attached becomes larger. ing. Even when the area where the vibration isolator is attached is small (10800 mm ² ), the noise is greatly reduced as compared with the case where the vibration isolator 11 is not attached.

[Brief description of the drawings]

FIG. 1 is an illustrative plan view showing a part of a laser beam printer according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 top cover 4 bottom plate 5 housing 6 outer peripheral wall 7 inner peripheral wall 11 anti-vibration material 14 polygon mirror 16 photoconductor 17 laser scanning device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masanori Kiyama 1-2-28 Tamazo, Chuo-ku, Osaka-shi, Osaka Inside Kyocera Mita Co., Ltd. (72) Inventor Takayuki Kurihara 1-2-2 Tamazo, Chuo-ku, Osaka-shi, Osaka No. 28 Inside Kyocera Mita Co., Ltd. (72) Eiji Tatsumi, inventor 1-2-2 Tamatsuzo, Chuo-ku, Osaka, Osaka Prefecture Inside No. 28 Kyocera Mita Co., Ltd. Yuichi Ninomiya 1-2-1, Tamazo, Chuo-ku, Osaka, Osaka No. 28 Inside Kyocera Mita Co., Ltd. (72) Inventor Hideki Sugimura 1-2-28 Tamazo, Chuo-ku, Osaka City, Osaka Prefecture F-term inside Kyocera Mita Co., Ltd. 2C362 DA17 DA23 2H045 AA33 AA49 DA02 DA04 DA44

Claims (4)

[Claims] 1. A housing having at least a part of a double wall structure forming a closed space, and a polygon mirror housed inside the housing and for scanning a laser beam. Laser scanning device. 2. The laser scanning device according to claim 1, wherein said double wall structure is formed integrally with a part of said housing. 3. The laser scanning device according to claim 1, further comprising an anti-vibration member attached to said housing. 4. An image forming apparatus comprising: a photoreceptor; and the laser scanning device according to claim 1 for writing an electrostatic latent image on the photoreceptor.