JPH1114930A - Deflection scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To seal the part between an optical box and a lid member. SOLUTION: When a rotary polygon mirror 3 in the optical box 10 rotates, outside air is sucked from between the optical box 10 and lid member 20 to contaminate the rotary polygon mirror 3, etc. For the purpose, a lib 11 is provided to the upper end of the side wall of the optical box 10 and an elastic member 21 is made to abut against the inside of the lib 11 and the external surface of the lid member 20, thereby sealing the part between the optical box 10 and lid member 20. The elastic member 21 is incorporated from outside the lid member 20, so neither double walls as the side wall of the optical box 10 nor a flange, etc., is necessary like a case wherein the elastic member is held between the optical box 10 and lid member 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As shown in FIG. 6, a deflection scanning device used in an image forming apparatus such as a laser printer or a laser facsimile collimates a laser beam generated from a semiconductor laser 101 by a collimator lens 101a and converts the laser beam into a cylindrical lens 102. Is condensed into a linear light beam, and is deflected and scanned by the rotary polygon mirror 103 in a predetermined direction (Y-axis direction) perpendicular to the direction along the rotation axis (Z-axis direction),
An image is formed on the photoconductor on the rotating drum 105 via the scanning lens 104. The light beam that forms an image on the photoreceptor is
Main scanning in the Y-axis direction by the rotation of
The electrostatic latent image is formed with the sub-scan in the Z-axis direction by the rotation of.

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 light is introduced into the BD sensor 107 via the condenser lens 106, and converted into a scan start signal by a controller (not shown), and the semiconductor laser 101
Send to The semiconductor laser 101 starts write modulation after receiving the scanning start signal.

The scanning lens 104 comprises a spherical lens section and a toric lens section, and scans the scanning light L ₀ scanned at a constant angular velocity by the rotating polygon mirror 103 on the rotating drum 105 at a constant speed in the Y-axis direction. It has a so-called fθ function of converting light.

A semiconductor laser 101, a cylindrical lens 102, a rotary polygon mirror 103, a scanning lens 104, a condenser lens 106, a BD sensor 107, etc.
Attached to the side wall and bottom wall. The rotating drum 105 is disposed outside the optical box 110, and the scanning light L ₀ is applied to the side of the optical box 110 by the rotating drum 10.
A window for taking out toward 5 is provided. The upper opening of the optical box 110 is provided with the lid member 12 shown in FIG.
Closed by 0.

As shown in FIG. 8, a motor for rotating the polygon mirror 103 includes a motor housing 103a supported on the bottom wall of an optical box 110 and a drive circuit mounted on a motor board 103b integrated with the housing. And a magnetic circuit including a stator 103c excited by a drive current of the drive circuit and a rotor 103d opposed thereto. The stator 103c is
b, a stator core and a stator coil wound therearound. The rotor 103d is fixed to a washer integral with the rotating shaft 103e, and the rotating polygon mirror 1
03 is pressed by a washer by a pressing spring or the like, and is integrally connected to the rotor 103d via the washer. When the stator 103c is excited as described above, the rotor 103d
And the rotary polygon mirror 103 rotate integrally.

At the upper end of the side wall of the optical box 110, a screw hole 1 is provided.
11 (see FIG. 6), the outer peripheral portion of the lid member 120 is brought into contact with the upper end of the side wall of the optical box 110, and the screw hole 1 is formed.
By screwing a screw 112 (see FIG. 7) to 11 and tightening it, the lid member 120 is assembled to the optical box 110.

[0008]

However, according to the above-mentioned prior art, there is no gap between the upper end of the side wall of the optical box and the outer peripheral portion of the lid member screwed to the optical box due to warpage of the lid member. A uniform gap is formed. For example, when the lid member is made of sheet metal, a gap of about 0.1 to 0.3 mm is formed between the lid member and the optical box due to unevenness in flatness or the like.

As described above, if the contact of the lid member with the side wall of the optical box is unstable, the lid member rattles when the rotary polygon mirror is rotated at a high speed, and a large noise is generated. _As shown by ₀ , outside air flows from the optical box 1 through a gap between the upper end of the side wall of the optical box 110 and the lid member 120.
10, the rotating polygon mirror 1 is invaded by dust and the like in the outside air.
03 is contaminated. Such a trouble occurs, for example, when the gap between the optical box 110 and the lid member 120 is 0.
Even when the distance is about 2 mm, dust of about several μm to several tens of μm passes therethrough, so that the rotary polygon mirror 103 and the imaging lens 104 are contaminated, which leads to deterioration of image quality and the like.

Therefore, as shown in FIG.
The optical box 110 and the lid member 120 are hermetically sealed by interposing an elastic material 121 such as foamed polyurethane between the upper end of the side wall and the outer peripheral portion of the lid member 120. The elastic member 121 is filled in the groove 110 a formed at the upper end of the side wall of the optical box 110, and
To prevent the outside air from being sucked into the optical box 110 and reduce contamination of the rotary polygon mirror 103 and the like.

However, in order to provide a groove 110a for filling the elastic material 121 at the upper end of the side wall of the optical box 110, the side wall of the optical box 110 is made thicker, the side wall is made double, or a flange is provided at the upper end. in the method of equal, it is necessary to ensure a sufficient width D ₀ to dispose the groove 110a, as a result, there is a disadvantage that the optical box 110 is significantly large.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and completely seals the space between the lid member and the optical box without increasing the size of the optical box. It is an object of the present invention to provide a high-performance deflection scanning device capable of effectively preventing contamination of a mirror or the like.

[0013]

In order to achieve the above object, a deflection scanning apparatus according to the present invention comprises a scanning optical system having a rotary polygon mirror for deflecting and scanning a light beam, an optical box accommodating the scanning optical system, and an optical box. A lid member for closing the opening of the optical box; a driving unit for rotating the rotary polygon mirror; and an elastic material abutting on an outer surface of the lid member and a peripheral edge of the opening of the optical box. And

[0014] The elastic material is preferably foamed polyurethane.

[0015] Preferably, an elastic material is adhered to the outer surface of the lid member.

A projection may be provided on the outer surface of the lid member, and an elastic material may be press-fitted into the projection and the periphery of the opening of the optical box.

[0017]

The gap between the optical box and the lid member is sealed by an elastic material disposed outside the lid member, thereby preventing outside air from entering the optical box and contaminating the rotary polygon mirror and the like. Since a projection such as a rib is provided on the periphery of the opening of the optical box, and the elastic material is brought into contact with the outer surface of the lid and the lid,
It is not necessary to unnecessarily make the side wall and the like of the optical box thick or double wall.

The optical box and the lid member can be completely sealed without increasing the size of the optical box as in the case where the side wall of the optical box is double-walled or thick.

[0019]

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

FIG. 1 shows a deflection scanning device according to an embodiment. A laser beam, which is a light beam generated from a semiconductor laser 1, is collimated by a collimator lens 1a and is converted into a linear light beam by a cylindrical lens 2. The light is condensed and enters the reflection surface of the rotary polygon mirror 3. The reflected light is deflected and scanned by the rotation of the rotating polygon mirror 3 to become scanning light in the Y-axis direction (main scanning direction), and passes through a scanning lens 4 that forms a scanning optical system together with the rotating polygon mirror 3, on the rotating drum 5. An image is formed on the photoconductor. The light beam that forms an image on the photoreceptor forms an electrostatic latent image with the main scanning in the Y-axis direction by the rotation of the rotating polygon mirror 3 and the sub-scanning in the Z-axis direction by the rotation of the rotating drum 5.

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

The scanning light of the rotary polygon mirror 3 reaches one end of the scanning surface, and passes through the condenser lens 6a to the BD sensor 6.
b, converted into a scanning start signal by the controller, and transmitted to the semiconductor laser 1. Semiconductor laser 1
Starts write modulation based on image information transmitted from a host computer (not shown) after receiving a scan start signal.

A semiconductor laser 1, a cylindrical lens 2, a rotary polygon mirror 3, a scanning lens 4, and condenser lenses 6a, B
The D sensor 6b and the like are attached to the side and bottom walls of the optical box 10 made of synthetic resin. The rotating drum 5 is provided outside the optical box 10, and a window for extracting scanning light from the optical box 10 toward the rotating drum 5 is provided on a side wall of the optical box 10. The upper opening, which is the opening of the optical box 10, is closed by a sheet metal lid member 20 (see FIG. 2).

The scanning lens 4 comprises a spherical lens unit and a toric lens unit, 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 5. So-called fθ function.

As shown in FIG. 2, a motor, which is a driving means for rotatingly driving the polygon mirror 3, includes a motor housing 3a supported on the bottom wall of the optical box 10 and a drive (not shown) mounted on the motor board 3b. And a magnetic circuit including a stator 3c excited by a drive current of the drive circuit and a rotor 3d opposed thereto. The stator 3c has a stator core erected on the motor board 3b and a stator coil wound therearound, and the rotor 3d is fixed to a washer integrated with the rotating shaft 3e. The rotating polygon mirror 3 is pressed against a washer by an elastic pressing mechanism having a holding spring or the like, and the rotor 3 is rotated via the washer.
d. When the stator 3c is excited as described above, the rotor 3d and the rotating polygon mirror 3 rotate integrally.

At the periphery of the opening of the optical box 10,
A rib 11 which protrudes further upward from the upper end of the side wall of the first member, and a contact portion 12 which contacts the outer peripheral portion of the lid member 20.
And a screw hole 12 a is formed in the contact portion 12. That is, the screw is screwed into the screw hole 12a of the contact portion 12 of the optical box 10 and the screw is tightened, so that the lid member 20 is assembled to the optical box 10.

In general, the cover member 20 made of sheet metal has unevenness in flatness due to warpage or the like. Therefore, when the cover member 20 is screwed to the contact portion 12 of the optical box 10, the distance between the two is 0.1 to 0.3 m.
A gap of about m is formed. Therefore, an elastic material 21 made of foamed polyurethane or the like is provided inside the rib 11 of the optical box 10.
Is mounted, the bottom surface of the elastic member 21 is brought into contact with the outer surface of the lid member 20, and the elastic member 21 is bonded with an adhesive. In other words, the outer peripheral surface of the elastic member 21 is brought into close contact with the rib 11 of the optical box 10 with the outer peripheral portion of the lid member 20 interposed between the contact portion 11 of the optical box 10 and the elastic member 21, and the elastic member 21 is covered. By bonding to the outer surface of the member 20, the space between the lid member 20 and the optical box 10 is completely sealed.

As described above, the space between the lid member 20 and the optical box 10 is completely sealed to prevent outside air from entering the optical box 10, and the rotating polygon mirror 3 and the imaging lens due to dust and the like in the outside air. 4 reduce contamination. As a result, a high-performance deflection scanning device that can be operated for a long time without maintenance can be realized.

Since the elastic member 21 is configured to be mounted on the outer surface of the lid member 20, the size of the optical box 10 increases when the elastic member is supported on the upper end of the side wall of the optical box 10. It is not.

During operation, the optical box 1 is heated by the heat of the motor.
Although there is a risk that the inside of the cover member 0 may rise in temperature, the lid member 20 is made of a metal having good heat conductivity, and only the elastic member 21 is attached to the outer peripheral portion thereof. As shown in FIG. Since most of the outer surface of the device contacts the outside air, sufficient heat radiation is performed through the lid member 20. in this way,
Since the center of the elastic member 21 is largely removed, the heat radiation effect of the lid member 20 is not impaired.

Since the elastic member 21 is mounted on the lid member 20, even if dirt or the like may fall off from the elastic member 21 made of foamed polyurethane or the like, these may be removed from the inside of the optical box 10. There is a remarkable advantage that there is no danger that the rotating polygon mirror 3 and the imaging lens 4 will be contaminated by entering the mirror.

FIG. 4 shows a modification. This means that instead of bonding the elastic member 21 to the lid member 20, the lid member 30
A plurality of protrusions 30a, which are protrusions, are provided on the upper surface (outer surface) of the
The elastic member 31 is fixed by holding the elastic member 31. If the lid member 30 is made of synthetic resin, it is easy to integrally form the projection 30a.

Since it is only necessary to push the elastic member 31 between the rib 11 of the optical box 10 and the projection 30a of the lid member 30,
The assembly cost can be significantly reduced as compared with the case where an adhesive is used.

If necessary, as shown in FIG. 5, a rib 40a, which is a protruding portion, is provided on the outer peripheral portion of the lid member 40 so as to face the rib 11 of the optical box 10.
The elastic member 41 may be sandwiched between 40a. In this case, even if the elastic member 41 floats for some reason, there is an additional advantage that the seal between the lid member 40 and the optical box 10 is not damaged, and a more reliable sealing structure can be realized.

[0035]

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

The space between the lid for closing the opening of the optical box and the optical box is completely sealed by an elastic material to prevent the invasion of outside air. In addition, the elastic member has an effect of reducing vibration of the lid member. As a result, it is possible to realize a small and high-performance deflection scanning device which is quiet in driving noise, suitable for high speed operation, and can be operated for a long time without maintenance. By mounting such a deflection scanning device, it is possible to greatly contribute to improving the performance of the image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a deflection scanning device according to an embodiment with a lid member removed.

FIG. 2 is a cross-sectional view showing a state where a lid member is attached to the apparatus of FIG.

FIG. 3 is a plan view showing the apparatus of FIG. 2;

4A and 4B show a first modified example, in which FIG.
(B) is a partial sectional view showing a part thereof.

5A and 5B show a second modified example, in which FIG.
(B) is a partial sectional view showing a part thereof.

FIG. 6 is a schematic plan view showing a conventional example with a lid member removed.

FIG. 7 is a schematic plan view showing a state where a lid member is attached to the apparatus of FIG. 6;

FIG. 8 is a schematic sectional view showing the device of FIG. 7;

FIG. 9 is a partial sectional view showing a main part of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 3 Rotating polygon mirror 4 Scanning lens 10 Optical box 11, 40a Rib 20, 30, 40 Lid member 21, 31, 41 Elastic material 30a Projection

Claims (5)

[Claims] 1. A scanning optical system having a rotary polygon mirror for deflecting and scanning a light beam, an optical box for housing the same, a lid member for closing an opening of the optical box, and a driving unit for rotating the rotary polygon mirror. A deflection scanning device having an elastic material in contact with an outer surface of the lid member and a peripheral edge of the opening of the optical box. 2. The deflection scanning device according to claim 1, wherein the elastic material is polyurethane foam. 3. The deflection scanning apparatus according to claim 1, wherein the elastic member is bonded to an outer surface of the lid member. 4. A projection is provided on an outer surface of the lid member, and an elastic material is press-fitted into the projection and a periphery of an opening of the optical box. 2. The deflection scanning device according to claim 1. 5. The deflection scanning device according to claim 1, wherein the optical box is made of a synthetic resin.