JPH1184301A - Scanning optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce the dustproofing of an optical box. SOLUTION: One part of the scanning light of a rotary polygon mirror 3 is separated by a signal detecting mirror 6 and is introduced into a signal detecting sensor 8 to be converted into a scanning state signal. A hole 20a in which a connector 8a connecting the signal sensor 8 to an external controller is provided is covered with a cover 23 and a cable 8b is drawn out from a notched part 23c of the cover 23. Then, it is prevented that lots of the open air flow in an optical box from the hole 23a of a lid member 20 to contaminate the rotary polygon mirror 3 or the like.

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 As shown in FIG. 6, a scanning optical device used for an image forming apparatus such as a laser beam printer or a laser facsimile collimates a laser beam generated from a semiconductor laser 101 by a collimator lens 102a.
After adjusting the beam shape by the aperture 102b, the beam is condensed into a linear light beam by the cylindrical lens 102c, and a predetermined direction (Y axis) perpendicular to the direction along the rotation axis (Z axis direction) by the rotary polygon mirror 103. Direction) and scans the rotating drum 10 through the imaging lens system 104.
5 on the photoreceptor. The light flux that forms an image on the photoconductor is
An electrostatic latent image is formed by main scanning in the Y-axis direction by rotation of the rotating polygon mirror 103 and sub-scanning in the Z-axis direction by rotation of the rotating drum 105.

In this manner, scanning for writing image information on the photosensitive member of the rotating drum 105 is repeated, but the writing position on the rotating drum 105 may be shifted due to a division error of the reflection surface of the rotating polygon mirror 103. There is. Therefore, the scanning light L ₀ of the rotating polygon mirror 103 is transmitted to the scanning plane (X
At one end in the Y-axis direction (Y plane), the signal detection mirror 10
6, the light is separated below the scanning surface by the condensing lens 1
The signal is introduced into the signal detection sensor 107 through 06a, and is exchanged with 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 the scanning light L ₀ scanned at a constant angular velocity into the scanning light that scans on the rotating drum 105 in the Y-axis direction at a constant velocity.

[0005] A semiconductor laser 101, a cylindrical lens 102c, a rotary polygon mirror 103, an imaging lens system 104,
The signal detection mirror 106, the signal detection sensor 107, and the like are attached to a side wall or a bottom wall of an optical box (not shown). Rotating drum 105 is disposed outside the optical box, the like the side wall of the optical box, rotary drum 10 scan light L ₀ from the optical box
A window for taking out toward 5 is provided. The opening of the optical box is closed by a lid member.

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

[0007]

However, according to the above-mentioned prior art, as described above, necessary components such as a rotary polygon mirror, an imaging lens system, and a signal detection sensor are incorporated into an optical box. The opening of the optical box is closed by a lid member. The lid member is provided with a connector for attaching the optical box to the optical box and then electrically connecting the signal detection sensor to an external controller or the like. A hole is provided, and when the rotating polygon mirror is rotated, outside air is sucked into the optical box from this hole, and floating dust and the like adhere to the reflecting surface of the rotating polygon mirror and the lens surface of the imaging lens system. There are unresolved issues.

When the optical components such as the rotary polygon mirror and the imaging lens system are contaminated by the outside air flowing into the optical box, these optical characteristics are deteriorated and the image quality is deteriorated.
As a result, the cost of maintenance increases and the life of the device is shortened. In recent years, the speed of the scanning optical device has been increased, and the amount of outside air sucked into the optical box tends to increase as the rotation speed of the rotary polygon mirror increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has been made to prevent dust from entering an optical box by preventing outside air from entering through a hole in a lid member. It is an object of the present invention to provide a high-performance scanning optical device suitable for high-speed operation which can maintain good image quality without maintenance for a period.

[0010]

In order to achieve the above object, a scanning optical apparatus according to the present invention comprises: a rotary polygon mirror for deflecting and scanning a light beam to convert it into scanning light; Imaging means for forming an image, a signal detection sensor for detecting a part of the scanning light as a scanning start signal, an optical box containing the signal detection sensor, the rotating polygon mirror, and the imaging means, and an opening thereof And a cover for covering a hole provided in the lid member for connecting an electric connection means to the signal detection sensor.

[0011] The cover may be formed integrally with the lid member.

[0012] The cover may be connected to the lid member by connecting means.

[0013] The cover may be provided with a cutout for drawing out a cable of the electric connection means.

An elastic member for sealing the space between the cable and the cable may be provided in the notch of the cover.

It is preferable that an elastic member for sealing between the hole of the lid member and the cover is provided.

[0016]

The lid of the optical box is provided with a hole for arranging a connector for connecting a signal detection sensor to an external controller, etc. If this remains open, a large amount of outside air will enter the optical box. As a result, the rotating polygon mirror and the imaging means are contaminated. Then, by covering such a hole of the lid member with a cover, inflow of outside air is prevented.

The cover may be provided integrally with the lid member by providing a hinge with a thin portion on the lid member, or may be manufactured separately from the lid member and assembled to the lid member by coupling means. The cover is provided with a cutout for drawing out a cable such as a connector.

If the gap between the cutout portion of the cover and the cable or the gap formed between the hole of the lid member and the cover is sealed by an elastic member, the dustproof effect of the optical box can be further enhanced. .

[0019]

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 L _1, which is a light beam generated from a semiconductor laser _1, is collimated by a collimator lens _{1 a and} is linearly formed by a cylindrical lens 2. The light is condensed into a light beam and enters the reflecting surface of the rotary polygon mirror 3. The reflected light is deflected and scanned by the rotation of the rotary polygon mirror 3, and
The light becomes scanning light in the Y-axis direction (main scanning direction), and forms an image on a photoreceptor on a rotating drum (not shown) via an imaging lens system 4 serving as an imaging means and a folding mirror 5. The luminous flux that forms an image on the photoreceptor is mainly scanned in the Y-axis direction by the rotation of the rotary polygon mirror 3, and
An electrostatic latent image is formed with the sub-scan in the Z-axis direction due to 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 scanning light of the rotary polygon mirror 3 reaches one end of the scanning surface and is reflected by the signal detecting mirror 6.
The light is introduced into the signal detection sensor 8 through the condenser lens 7, converted into a scanning start signal by a controller (not shown), and transmitted to the semiconductor laser 1. After receiving the scanning start signal, the semiconductor laser 1 starts writing modulation based on image information transmitted from the host computer of the apparatus.

The semiconductor laser 1, the cylindrical lens 2, the rotary polygon mirror 3, the imaging lens system 4, the signal detection mirror 6, the signal detection sensor 8 and the like are mounted on the side wall and the bottom wall of the optical box 10 made of synthetic resin. The rotating drum is an optical box 10
And a window 11 for taking out scanning light from the optical box 10 toward the rotating drum is provided on the bottom wall of the optical box 10. The upper opening of the optical box 10 is closed by a lid member 20 shown in FIG. 1B, and the lid member 20 is screwed to the optical box 10 at a peripheral edge thereof.

The imaging lens system 4 comprises a spherical lens 4a and a toric lens 4b, and converts scanning light scanned at a constant angular speed by the rotary polygon mirror 3 into scanning light scanning at a constant speed in the Y-axis direction on the rotating drum. It has a so-called fθ function for conversion.

When assembling the optical box 10 to the main body frame of the scanning optical device, first, the positioning pins 9a and 9b of the positioning unit that engage with the guide holes provided in the support portion 12 outside the optical box 10 are used. Optical box 1
Positioning in the X-axis direction (optical axis direction) and the θ-axis direction (rotation angle) is performed. The positioning in the X-axis direction is performed by moving both positioning pins 9a and 9b in the same direction in the X-axis direction with respect to the guide hole, and the rotation angle θ (θ
The axial position) is adjusted by moving the positioning pins 9a and 9b in opposite directions. After adjusting the relative position with respect to the photoconductor in this manner, the optical box 10 is fixed to the main body frame.

The signal detection sensor 8 is connected to an external controller by a connector 8a and a cable 8b as electric connection means. The lid member 20 is provided with a hole 20a that forms a gap having a width of about 2 mm around the connector 8a. If such a gap is left open around the connector 8a, outside air will And the rotating polygon mirror 3, the imaging lens system 4, the signal detection sensor 8, and the like are contaminated by floating dust and the like. Therefore, a cover 23 for closing the hole 20a of the lid member 20 is attached.

The cover 23 includes a main body 23a that covers the entire hole 20a of the lid member 20, and a locking portion 23b that is a coupling means that can be engaged with the locking claw 21 formed integrally with the lid member 20.
And a notch 23c for pulling out the cable 8b of the connector 8a.
As shown in FIG. 2, the cover 3 is attached to the cover 20 over the hole 20 a from above the cover member 20, and the locking portion 23 b is snap-fitted to the locking claw 21 of the cover member 20. The notch 23c of the cover 23
It is only necessary that the opening is large enough to pull out the cable 8b. Therefore, the opening area is much smaller than the hole 20a of the lid member 20, and the invasion of the outside air can be greatly reduced.

As described above, the cover 2 having an extremely simple structure
By simply attaching the cover 3 to the lid member 20, the amount of outside air entering the optical box 10 can be greatly reduced, and a high-performance scanning optical device capable of maintaining good image quality without maintenance for a long time can be realized.

FIG. 3 shows a first modification. This is because a cover 33 for closing the hole 30a is integrally formed with a lid member 30 made of a flexible resin material such as polypropylene, and a thin portion 30b is provided.
3 constitutes a hinge for elastically turning the upper part 3 upward. The free end of the cover 33 is provided with a locking portion 33b that snap-fits to the locking claw 31 of the lid member 30, and a cutout portion 33c is formed in the main body portion 33a for drawing out the cable 8b of the connector 8a. Have been.

By integrally molding the lid member 30 and the cover 33, the advantage that the number of assembly parts can be reduced and the assembly process can be simplified can be added.

FIG. 4 shows a second modification. This is due to the notch 43c of the cover 43 closing the hole 40a of the lid member 40.
, An elastic member 44 such as an elastomer is disposed on the cover 43.
The elastic member 44 comes into close contact with the cable 8b when the cover member 40 is snap-fitted to the lid member 40, and the gap between the elastic member 44 and the notch 43c is sealed.

The optical box 10 is inserted through the notch 43c of the cover 43.
By preventing the outside air from entering inside, the dustproof effect of the cover 43 can be further enhanced.

FIG. 5 shows a third modification. This is achieved by arranging an elastic member 54 such as an elastomer in a notch 53c of a cover 53 that closes a takeout opening 50a of the lid member 50 to seal a gap between the cable 8b and a separate body from the lid member 50. From the assembled part of the cover 53
In order to prevent outside air from entering the inside, an elastic member 55 similar to the above is disposed on the outer peripheral portion of the cover 53, and this is brought into close contact with the surface of the lid member 50 to seal the assembly portion. It was done.

By preventing the outside air from entering through the outer peripheral portion of the cover 53 and the notch 53c, the dustproof effect of the cover 53 can be further enhanced.

[0035]

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

By preventing the outside air from entering through the hole of the lid member, it is possible to realize a high-performance scanning optical apparatus which can maintain good image quality without maintenance for a long period of time by enhancing dustproof of the optical box. 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]

FIGS. 1A and 1B show a scanning optical device according to an embodiment, in which FIG. 1A is a schematic plan view, and FIG. 1B is an enlarged partial cross-sectional view showing a mounting portion of a signal detection sensor in an enlarged manner.

FIG. 2 is a partial plan view showing a part of the apparatus of FIG. 1;

FIG. 3 is a partial sectional view showing a first modification.

FIG. 4 is a partial sectional view showing a second modification.

FIG. 5 is a partial sectional view showing a third modification.

FIG. 6 is a diagram illustrating a scanning optical device according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor laser 3 rotating polygon mirror 3 a motor 4 imaging lens system 5 folding mirror 6 signal detection mirror 8 signal detection sensor 8 a connector 8 b cable 10 optical box 10 a hole 20, 30, 40, 50 lid member 21 locking claw 23, 33 , 43, 53 Cover 23c, 33c, 43c, 53c Notch 44, 54, 55 Elastic member

Claims (6)

[Claims] 1. A rotary polygon mirror for deflecting and scanning a light beam to convert it into scanning light, an image forming means for forming an image of the scanning light on a photosensitive member, and detecting a part of the scanning light as a scanning start signal. A signal detection sensor, an optical box accommodating the signal detection sensor, the rotary polygon mirror, and the imaging means, a lid member for closing an opening thereof, and an electric connection means for connecting an electrical connection means to the signal detection sensor. A scanning optical device comprising a cover for covering a hole provided in a lid member. 2. The scanning optical device according to claim 1, wherein the cover is formed integrally with the lid member. 3. The scanning optical device according to claim 1, wherein the cover is connected to the lid member by connecting means. 4. The scanning optical device according to claim 1, wherein the cover has a cutout for drawing out a cable of the electric connection means. 5. The scanning optical device according to claim 4, wherein an elastic member for sealing between the notch portion of the cover and the cable is provided. 6. The scanning optical device according to claim 1, further comprising an elastic member for sealing between a hole of the lid member and the cover.