JP2001133719A - Scanning optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the outside air from being sucked in an optical box from a hole provided to drive a shutter. SOLUTION: Since a laser beard deflected and made to scan by a rotary polygon mirror 3 is harmful for a human body, this device is provided with a shutter device 12 for shielding a laser beam when the device is not operated. An elastic member 12c is stuck to a lever 12b pushing up a shutter plate 12a. As soon as the plate 12a is pushed up and the shutter is made open, the member 12c is brought into contact with the base of the optical box 10 and hermetically covers the hole 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device used for an image forming apparatus such as a laser beam printer and a laser facsimile.

[0002]

2. Description of the Related Art A scanning optical apparatus used in an image forming apparatus such as a laser beam printer or a laser facsimile reflects a light beam such as a laser beam by a rotating polygon mirror rotating at a high speed and deflects and scans the light beam. The scanning light is imaged on a photoreceptor on a rotating drum to form an electrostatic latent image.
Next, the electrostatic latent image on the photoreceptor is visualized into a toner image by a developing device, transferred to a recording medium such as recording paper, sent to a fixing device, and printed by heating and fixing the toner on the recording medium ( Print) is performed.

FIG. 6 shows a scanning optical device according to a conventional example, in which a laser beam generated from a semiconductor laser 101 is collimated by a collimator lens, a beam shape is adjusted by an aperture, and then a cylindrical lens 1 is formed.
02, the light is condensed into a linear light beam, deflected and scanned in the main scanning direction (Y-axis direction) by a rotating polygon mirror 103, and formed on a photosensitive drum on a rotating drum (not shown) via an imaging lens system 104 and a return mirror 105. Image. The light beam formed on the photoreceptor forms an electrostatic latent image in accordance with the main scanning in the Y-axis direction by the rotation of the rotating polygon mirror 103 and the sub-scanning in the Z-axis direction by the rotation of the rotating drum.

In this way, the scanning for writing image information on the photosensitive drum of the rotating drum is repeated, but the writing position on the rotating drum may be shifted due to the division error of the reflecting surface of the rotating polygon mirror 103. . Therefore, the scanning light L ₀ of the rotating polygon mirror 103 is changed to Y on the scanning surface (XY plane).
At one end in the axial direction, the light is separated below the scanning surface by the signal detection mirror 106, introduced into the signal detection sensor 107, converted into a scanning start signal by a controller (not shown), and transmitted to the semiconductor laser 101. The semiconductor laser 101 starts write modulation after receiving the scanning start signal.

The imaging lens system 104 includes a spherical lens 104
a and the toric lens 104b, and the rotating polygon mirror 1
03 has a so-called fθ function of converting scanning light L ₀ scanned at a constant angular velocity into scanning light scanning at a constant velocity in the Y-axis direction on the rotating drum.

A semiconductor laser 101, a cylindrical lens 102, a rotating polygon mirror 103, an imaging lens system 104, a signal detection mirror 106, a signal detection sensor 107 and the like are mounted on a side wall or a bottom wall of an optical box 110. Rotary drum is disposed outside of the optical box 110, the bottom wall of the optical box, window 111 for taking out toward the rotating drum scanning light L ₀ from the optical box 110 is provided. Also,
The upper opening of the optical box 110 is closed by a lid member (not shown).

A motor 1 for rotatingly driving the polygon mirror 103
Numeral 03a includes a motor circuit board 103b supported on the bottom wall of the optical box 110, a stator excited by a drive current of a drive circuit on the motor board 103b, and a magnetic circuit including a rotor and the like opposed thereto.

Further, if laser light harmful to the human body is erroneously emitted to the outside when the scanning optical device is not operating, for example, it is extremely dangerous for the operator. Therefore, a shutter device 11 for blocking laser light in an optical path between the light source unit including the semiconductor laser 101 and the rotary polygon mirror 103
2 are provided. As shown in FIG. 7, the shutter device 112 includes a cylindrical lens 102 and a rotating polygon mirror 10.
3 and a lever 112b for moving the shutter plate 112a up and down.
2a is a hole 11 formed in the bottom wall of the optical box 110.
0a, protrudes out of the optical box 110, and the lever 112
b.

The lever 112b is moved up and down or rotated by an actuator (not shown),
When a is pushed up, the opening of the shutter plate 112a is in a so-called shutter open state in which laser light passes.

[0010]

However, according to the above-mentioned prior art, when the rotary polygon mirror is rotated, a laser beam is shielded when the apparatus is not operated or the like, so that a shutter for securing the safety of the worker is provided. There is an unsolved problem that outside air is sucked into the inside of the optical box from the provided holes, and floating dust and the like adhere to the reflection surface of the rotating polygon mirror and the lens surface of the imaging lens system.

More specifically, as shown in FIG. 8, between the hole 110a in the bottom wall of the optical box 110 and the shutter plate 112a, a shutter plate 112 driven by a lever 112b is driven.
A gap A ₀ is required so as not to hinder the vertical movement of the shutter a. The gap A ₀ is raised by raising the shutter plate 112 a by the lever 112 b and opening the shutter plate 112 a so that the laser beam passes through the opening. Even when this happens, it is difficult to bring the lever 112b and the bottom wall of the optical box 110 into complete close contact with each other, so that it cannot be sealed, and outside air is sucked into the optical box 110 when the rotating polygon mirror rotates.

As shown in FIG. 9, the shutter plate 21 is inserted through a hole 220a provided in the lid member 220 of the optical box 210.
2a is exposed, and a shutter drive member 212b and a spring 212c are used to move the shutter plate 212a up and down by a spring 212c. However, the shutter plate 212a is also provided between the hole 220a of the lid member 220 and the shutter plate 212a. Requires a gap similar to that described above.
The outside air enters inside 0.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has a hole provided in an optical box or the like for a shutter for shielding a laser beam and ensuring the safety of an operator. It is an object of the present invention to provide a high-performance, high-speed scanning optical device capable of maintaining good image quality without maintenance for a long period of time while avoiding contamination of a rotary polygon mirror or the like by external air invading from the outside. It is.

[0014]

In order to achieve the above object, a scanning optical apparatus according to the present invention comprises a scanning means for deflecting and scanning a light beam generated from a light source, and forming an image of the light beam on a photosensitive member. Housing means for housing the imaging optical system to be made and the scanning means; a shutter provided in the optical path of the light beam; a driving member for driving the shutter; and at least one of the driving member and the housing means And an elastic member configured to seal the opening of the storage means together with the driving member.

It is preferable that the elastic member is provided on a contact surface of the driving member with respect to the housing means.

It is preferable that the elastic member is disposed around the opening of the storage means.

It is preferable that a low friction sheet material is adhered to the surface of the elastic member.

A shutter may be provided between the scanning means and the light source.

[0019]

A shutter for blocking a light beam such as a laser beam harmful to the human body when the apparatus is not operated is provided between the light source and the scanning means. Since the shutter plate constituting the shutter is driven by a driving member disposed outside the housing means, a part of the shutter plate is exposed to the outside through the opening of the housing means, and the shutter plate is inserted into the housing means from the opening. The outside air is sucked and contaminates the scanning means and the like. Therefore, the elastic member is provided integrally with the driving member and the housing means, and when the driving member opens the shutter, the elastic member is brought into contact with the outer surface of the housing means to seal the opening. To be configured.

The elastic member may be provided around an opening such as a bottom wall of the housing means so that the driving member comes into contact with the elastic member when the shutter is opened.

If a low friction plastic sheet or the like is adhered to the surface of the elastic member, troubles such as abrasion due to contact with the driving member and the housing means can be reduced.

[0022]

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

FIG. 1 shows a scanning optical device according to an embodiment. A laser beam, which is a light beam generated from a semiconductor laser 1 as a light source, is collimated by a collimator lens and is linearly formed by a cylindrical lens 2. The light is condensed into a light beam and is incident on the reflection surface of the rotary polygon mirror 3 which is a scanning unit. The reflected light is deflected and scanned by the rotation of the rotary polygon mirror 3 to become scanning light in the main scanning direction (Y-axis direction). The reflected light passes through an imaging lens system 4 which is an imaging optical system and a folding mirror 5 and is rotated by a rotating mirror (not shown). An image is formed on the photoconductor on the drum.
The light flux that forms an image on the photoreceptor is Y
An electrostatic latent image is formed by the main scanning in the axial direction and the sub-scanning in the Z-axis direction by the rotation of the rotating drum.

In the periphery of the photoreceptor, a charging device for uniformly charging the surface of the photoreceptor, a visualization device for visualizing an electrostatic latent image formed on the surface of the photoreceptor into a toner image, A transfer device or the like for transferring the toner image to a recording medium such as recording paper is provided, and by these operations, recording information corresponding to the light beam generated by the semiconductor laser 1 is printed on recording paper or the like.

The semiconductor laser 1, the cylindrical lens 2, the rotary polygon mirror 3, the imaging lens system 4 and the like are mounted on the side wall and the bottom wall of the optical box 10 which is a housing made of synthetic resin. The rotating drum is disposed outside the optical box 10,
The bottom wall of the optical box 10 is provided with a window 11 for taking out scanning light from the optical box 10 toward the rotating drum.
The upper opening of the optical box 10 is closed by a lid member (not shown).

The imaging lens system 4 is composed of two lenses, a spherical lens 4a and a toric lens 4b. Scanning light scanned at a constant angular speed by the rotary polygon mirror 3 is rotated at a constant speed in the Y-axis direction on the rotary drum. It has a so-called fθ function of converting into scanning light for scanning.

A motor 3a for rotating the polygon mirror 3
Is composed of a drive circuit on a motor substrate 3b supported on the bottom wall of the optical box 10, a magnetic circuit including a stator excited by a drive current of the drive circuit, a rotor opposed thereto, and the like.

Further, if laser light harmful to the human body is erroneously emitted to the outside when the scanning optical device is not operating, it is extremely dangerous for an operator performing maintenance or the like. Rotating polygon mirror 3
A shutter device 12 for blocking an optical path between the shutter devices is provided. As shown in FIG. 2, the shutter device 12 includes a shutter plate 12a serving as a shutter disposed between the cylindrical lens 2 and the rotary polygon mirror 3, and a lever 12b serving as a driving member for moving the shutter plate 12 up and down. And shutter plate 1
The lower portion of 2a projects out of the optical box 10 through a hole 10a, which is an opening formed in the bottom wall of the optical box 10, and is in contact with the upper surface of the lever 12b.

When the lever 12b is moved up and down or rotated by an actuator (not shown) to push up the shutter plate 12a, the opening of the shutter plate 12a is in a so-called shutter open state in which laser light passes.

The lever 12b has a sponge-like or rubber-like elastic member 12c on a contact surface for pushing up the shutter plate 12a. The elastic member 12c is integrated with the shutter plate 12a by a known method such as bonding. ing.

As shown in FIG. 3A, the lever 12b
Rises, the shutter plate 12 is moved through the elastic member 12c.
a is pushed up, and the opening of the shutter plate 12a is in a shutter-open state in which the laser beam passes. At this time,
The elastic member 12c is compressed between the bottom wall of the optical box 10 and the lever 12b, and comes into close contact with the bottom surface of the optical box 10 so that the lever 12
Together with b, the hole 10a of the optical box 10 is sealed from the outside of the optical box 10.

The material of the elastic member 12c is the lever 1
When compressed by 2b, it is necessary to select a sponge or the like having appropriate flexibility so as to absorb a shape error and an angle shift of the lever 12b and to be able to adhere to the bottom surface of the optical box 10.

From such a shutter open state, the lever 1
When the shutter 2b is lowered, as shown in FIG. 3B, the elastic member 12c separates from the lower end of the shutter plate 12a and returns to its original thickness, and the shutter plate 12a lowers to open its opening. Deviates from the optical path of the laser light to block the laser light, and the shutter is closed.

FIG. 4 shows a first modification. This is obtained by attaching a plastic sheet 12d, which is a low-friction sheet material, to the surface of an elastic member 12c fixed to the lever 12b. If the material of the elastic member 12c is sponge, rubber, or the like, the elastic member 12c comes into contact with the shutter plate 12a and easily wears each time the shutter is opened and closed as shown in FIGS. , Low durability. Therefore,
A plastic sheet 12d having a small coefficient of friction is attached to the surface of the elastic member 12c to reduce wear. This can contribute to extending the life of the device.

FIG. 5 shows a shutter device 2 according to a second modification.
2 is shown. This is because the lower end of the shutter plate 22a is connected to the lever 2
2b, the sponge-like or rubber-like elastic member 22c is stuck around the hole 20a, which is the opening of the optical box 20, which is a housing means, and the lever 22b rises to release the shutter plate 22a. When the shutter is opened by pushing up, the elastic member 22c is compressed by the lever 22b to seal the hole 20a of the optical box 20.

As described above, the elastic member may be integrated with the bottom wall of the optical box. If the driving member such as the shutter lever moves the shutter plate up and down from the outside of the lid member of the optical box, an elastic member for closing a hole which is an opening of the lid member is driven by the lid member or the driving member. It may be integrated with the member.

According to the present embodiment, outside air is prevented from being sucked into the optical box from a hole provided in the optical box or the like for a shutter for blocking laser light for the purpose of worker safety or the like. The inside of the optical box can be kept clean. As a result, contamination of the rotary polygon mirror and the like can be reduced, and a high-performance and inexpensive scanning optical device that can be operated without maintenance for a long time can be realized.

[0038]

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

A high-performance scanning system capable of preventing contamination of a rotary polygon mirror or the like due to outside air sucked into an optical box from a hole provided for a shutter and maintaining maintenance-free and good image quality for a long period of time. An optical device can be realized. By mounting such a scanning optical device, it is possible to greatly enhance the performance and speed of the image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a scanning optical device according to an embodiment.

FIG. 2 is a sectional view showing the apparatus of FIG. 1;

FIG. 3 is a diagram illustrating an opening and closing operation of a shutter.

FIG. 4 is a diagram illustrating a first modification.

FIG. 5 is a diagram illustrating a second modification.

FIG. 6 is a schematic plan view showing one conventional example.

FIG. 7 is a sectional view showing the device of FIG. 6;

FIG. 8 is a view for explaining an opening and closing operation of a shutter of the apparatus of FIG. 7;

FIG. 9 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 3 Rotating polygon mirror 3a Motor 4 Imaging lens system 5 Folding mirror 10, 20 Optical box 11 Window 12, 22 Shutter device 12a, 22a Shutter plate 12b, 22b Lever 12c, 22c Elastic member 12d Plastic sheet

Claims (7)

[Claims] 1. A scanning unit for deflecting and scanning a light beam generated from a light source, an imaging optical system for forming an image of the light beam on a photosensitive member, a housing unit for housing the scanning unit, and an optical path of the light beam. A driving member for driving the shutter, and at least one of the driving member and the accommodating means, wherein an opening of the accommodating means is sealed together with the driving member. A scanning optical device having a configured elastic member. 2. The scanning optical device according to claim 1, wherein the elastic member is provided on a contact surface of the driving member with respect to the housing means. 3. The scanning optical device according to claim 1, wherein the elastic member is provided around the opening of the storage means. 4. The scanning optical device according to claim 1, wherein a low-friction sheet material is attached to a surface of the elastic member. 5. The scanning optical device according to claim 1, wherein the elastic member is made of a sponge-like material. 6. The scanning optical device according to claim 1, wherein the elastic member is made of a rubber-like material. 7. The scanning optical device according to claim 1, wherein the shutter is provided between the scanning unit and the light source.