JP2000321519A - Optical scanner and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency in operation of the cleaning maintenance, etc., of a return mirror, etc. SOLUTION: The atmosphere around a rotary polygon mirror 3 is held clean with a molt plane 21 sealing the part between part of the side wall of an optical frame 10 and a cover 20 by being made to abut against the upper ends of the lenses of an image formation lens system 4. A hinge part 20c is provided between 1st and 2nd cover parts 20a and 20b of the cover 20 and only the 2nd cover part 20b is made freely openable so that the return mirror 5 when becoming dirty can be cleaned while the circumference of the rotary polygon mirror 3 is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art An optical scanning device 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.

FIGS. 3 and 4 show an optical scanning device according to a conventional example.
The light emitted from the semiconductor laser 101.
Laser light L which is a beam₀ Depends on the collimator lens
Collimated and linearized by cylindrical lens 102
And is incident on the reflecting surface of the rotating polygon mirror 103.
I do. The reflected light is rotated by the rotation of the polygon mirror 103.
It is deflected and scanned, and scan light in a predetermined direction (main scanning direction)
The imaging lens system 104, the folding mirror 105, etc.
Via rotating drum D₀ An image is formed on the upper photoconductor. Tied to photoconductor
The light beam to be imaged is scanned in the main scanning direction by rotating the polygon mirror 103.
And the rotating drum D ₀ Electrostatic due to sub-scanning due to rotation of
Form a latent image.

A charging device for uniformly charging the surface of the photoconductor is provided around the photoconductor, a visualization device for visualizing an electrostatic latent image formed on the surface of the photoconductor into a toner image, A transfer device or the like for transferring the toner image to a recording medium such as a recording paper is provided.
Is recorded on a recording sheet or the like corresponding to the light beam in which is generated.

The scanning light of the rotary polygon mirror 103 reaches one end of the scanning surface thereof, is reflected by a BD mirror 106 and is introduced into a BD sensor 107, where it is converted into a scanning start signal in a processing circuit and is transmitted to a semiconductor laser 101. Sent. After receiving the scan start signal, the semiconductor laser 101 starts write modulation based on image information transmitted from the host computer.

The semiconductor laser 101, cylindrical lens 102, rotating polygon mirror 103, imaging lens system 104, folding mirror 105, etc.
0. The rotating drum D ₀ is disposed outside the optical frame 110, and
A window 111 for taking out scanning light from the optical frame 110 to the outside is provided at one end of the reference numeral 0.

The imaging lens system 104 includes a plurality of lenses such as a spherical lens and a toric lens.
It has a so-called fθ function for converting the scanning light scanned at a constant angular velocity in the scanning beam to scan at a constant velocity on a rotary drum D ₀ by 03.

The upward opening of the optical frame 110 is obtained by assembling the rotating polygon mirror 103, the imaging lens system 104, the folding mirror 105, and the like inside the optical frame 110.
It is closed by the cover 120.

A motor 1 for driving the rotary polygon mirror 103 to rotate.
Reference numeral 03a denotes a drive circuit (not shown) mounted on the motor board 103b, and a magnetic circuit including a stator excited by a drive current of the drive circuit, a rotor opposed thereto, and the like.

The optical frame 110 is required to have high strength, high accuracy and low cost. For example, 25% of GF (graphite fiber) is added to PC-ABS (a mixture of PC resin and ABS resin). Is used. The material of the cover 120 is PC-ABS, and the color of the optical frame 110 and the cover 120 is generally black to prevent flare due to light reflection.
The cover 120 is fixed by screwing its outer peripheral portion to the upper end of the optical frame 110.

When the rotating polygon mirror 103 rotates at high speed, the optical
Outside air is sucked from between the frame 110 and the cover 120.
The reflection surface of the rotating polygon mirror 103 is contaminated by dust and the like.
It is. Therefore, the atmosphere around the rotating polygon mirror 103 is sealed.
Between the optical frame 110 and the cover 120
A moltoprene 121 is provided. Moltprene 121
Is an optical frame divided into two by the imaging lens system 104.
Internal space A of the room 110 ₁ , A_Two Among the rotating polygon mirror
Internal space A that houses 103₁ Sealed hands for sealing
As a step, the upper end of the lens of the imaging lens system 104 and this
Upper end of side wall 110a of optical frame 110 on the more upstream side
Is a frame-shaped sealing member that is in contact with
Pressure is applied between the upper end of the side wall 110a of the optical frame 110 and the like.
It is clamped in a compressed state.

[0012]

However, according to the above-mentioned prior art, the first internal space of the optical frame accommodating the rotary polygon mirror is sealed by moltoprene, while the second internal space is sealed. However, the folding mirror, the lens surface of the imaging lens system, and the like disposed here are contaminated by dust and toner entering the optical frame. When the return mirror and lens are contaminated, maintenance such as wiping to clean them is necessary, but the rotating drum is located below the optical scanning device. Since the color of the optical frame and the cover is black, the inside of the optical frame is dark, and it is extremely difficult to insert cloth or paper through a window or the like of the optical frame and perform cleaning work such as wiping.

Further, if the cover is opened at a user site or the like in order to clean dirty parts, dust or the like enters the first internal space sealed by the maltprene, and when the operation is resumed, the dust rotates. There were also problems such as contamination of the reflection surface of the polygon mirror.

In particular, in order to prevent contamination by toner,
Dust-proof glass is arranged between the optical scanning device and the rotating drum to prevent the return mirror and the like from becoming dirty.However, since the dust-proof glass is placed near the rotating drum to which toner and the like easily adhere, the dust-proof glass is turned back. The number of cleaning services increases. As described above, not only is the place where the dust-proof glass is installed close to the developing unit, but generally, the closer the drum surface is, the smaller the luminous flux of the laser light is. As a result, the required number of cleaning services is greatly increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and has only a part of a cover which closes an opening of an optical frame is opened, so that a lens surface of a folding mirror or an image forming lens system is opened. It is an object of the present invention to provide a high-quality optical scanning device and an image forming apparatus capable of greatly improving the working efficiency of maintenance and the like.

[0016]

In order to achieve the above object, an optical scanning device according to the present invention comprises: a deflection scanning means for deflecting and scanning a light beam; An optical frame provided with an imaging optical unit for forming an image, a first internal space containing the deflection scanning unit, and a second internal space containing at least a part of the imaging optical unit; A cover for closing the opening, wherein the cover opens and closes the second internal space with the first cover portion closing the first internal space of the optical frame and the first cover member closed It is characterized by having a second cover portion that is free.

[0017] The cover may be provided with locking means for fixing the second cover part to the optical frame by snap-fitting.

[0018] The cover has a second cover portion with respect to the first cover portion.
It is good to have the hinge part which connects the cover part of this in a freely rotatable manner.

The first cover portion and the second cover portion may be separate.

[0020] The first cover portion may be made of metal.

A lock member for temporarily fixing the second cover portion in an open state may be provided.

[0022]

The first internal space of the optical frame incorporating the deflection scanning means such as a rotary polygon mirror is sealed by a first cover portion and a sealing means such as maltoprene to prevent outside air from entering. The second internal space of the optical frame incorporating the lens of the imaging optical means and the folding mirror is not sealed, and requires maintenance such as cleaning service.

Therefore, while the first internal space of the optical frame is kept sealed by the first cover portion of the cover, only the second cover portion closing the second internal space of the optical frame can be opened and closed. Constitute. When the above maintenance is required, the second cover portion is opened, and the cleaning operation or the like can be performed efficiently.

[0024] If the cover is provided with locking means for fixing the second cover portion to the optical frame by snap fitting, the second cover portion can be easily opened and closed.

[0025] The cover may be configured such that the first cover portion has a second cover portion.
The cover can be integrally formed of a resin material or the like if it has an integral structure having a hinge portion for pivotally connecting the cover portion.

If the first cover part and the second cover part are separate parts and the first cover part is made of metal, the heat generated from the motor of the deflection scanning means can be effectively dissipated. There is an advantage.

If a lock member for temporarily fixing the second cover portion to the first cover portion or the like with the second cover portion opened is provided, the second cover portion is temporarily fixed with the second cover portion opened. In addition, the efficiency of maintenance work such as cleaning service can be greatly improved.

[0028]

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

FIG. 1 shows an optical scanning device according to an embodiment. A laser beam L _1, which is a light beam emitted from a semiconductor laser _1, is collimated by a collimator lens, and a linear light beam is emitted by a cylindrical lens 2. And is incident on the reflection surface of the rotary polygon mirror 3 which is a deflection scanning means. The reflected light is deflected and scanned by the rotation of the rotary polygon mirror 3 to become scanning light in a predetermined direction (main scanning direction), and is rotated through an imaging lens system 4 and a return mirror 5 constituting imaging optical means. a imaging plane on the rotary drum D ₁ is a means to form an image on the photosensitive member. The light beam forms an image on the photosensitive member forms a main scanning by rotation of the rotary polygon mirror 3, an electrostatic latent image is accompanied in the sub scanning by rotation of the rotary drum D _1.

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 BD mirror 6 so that the
The light is introduced into the sensor 7, converted into a scanning start signal in the processing circuit, and transmitted to the semiconductor laser 1. After receiving the scan start signal, the semiconductor laser 1 starts write modulation based on image information transmitted from the host computer.

The semiconductor laser 1, the cylindrical lens 2, the rotating polygon mirror 3, the imaging lens system 4, the folding mirror 5
Are mounted inside the optical frame 10 made of synthetic resin. Rotary drum D ₁ is arranged outside the optical frame 10, a window 11 for taking out the external scanning light from the optical frame 10 is provided at one end of the optical frame 10.

The imaging lens system 4 includes a plurality of lenses, a so-called fθ function for converting the scanning light scanned at a constant angular velocity by a rotating polygonal mirror 3 on the scanning light for scanning at a constant velocity on a rotary drum D ₁ etc. Having.

The upward opening of the optical frame 10 is closed by the cover 20 after assembling the rotary polygon mirror 3, the imaging lens system 4, the folding mirror 5, and the like in the optical frame 10.

As shown in FIG. 2, a motor 3a for rotatingly driving the rotary polygon mirror 3 includes a drive circuit (not shown) mounted on a motor substrate 3b, a stator excited by a drive current of the drive circuit, and a stator opposed thereto. It is configured by a magnetic circuit including a rotating rotor and the like.

Since the optical frame 10 is required to have high strength, high precision, and be inexpensive, for example, a resin material with 25% GF added to PC-ABS is used. The colors of the optical frame 10 and the cover 20 are
Generally black to prevent flare due to light reflection.

When the rotating polygon mirror 3 rotates at a high speed, outside air is sucked from between the optical frame 10 and the cover 20, and the reflection surface of the rotating polygon mirror 3 is contaminated with dust or the like. Therefore,
In order to seal the atmosphere around the rotary polygon mirror 3, a moltoprene 21 which is a sealing means for sealing between the optical frame 10 and the cover 20 is provided. Moltprene 21
Is such that, of the internal spaces A ₁ and A ₂ of the optical frame 10 divided by the lenses of the imaging lens system 4, the first internal space A ₁ that accommodates the rotating polygon mirror 3 is sealed.
A frame-shaped member which is in contact with the upper end of the lens of the imaging lens system 4 and the upper end of the side wall 10a of the optical frame 10 on the upstream side thereof;
Between the upper end of the lens and the upper end of the lens in a compressed state.

The material of the cover 20 is polypropylene, which is a resin material having flexibility and durability against bending. The cover 20 is provided on the first and second optical frames 10.
A hinge portion 20c is provided between the first and second cover portions 20a and 20b for closing the internal spaces A ₁ and A ₂ respectively. The first cover portion 20a is closed and the second cover portion 20a is closed. the second cover portion 20b to pivot, and is configured to open and close only the second internal space a _2.

More specifically, the thickness of the entire cover 20 is about 2 mm, but only the hinge 20c has a thickness of 0.7 m.
m thick to give flexibility, and the second cover portion 20b
Opening and closing operations are facilitated. As described above, the first internal space A ₁ on the rotating polygon mirror 3 side of the optical frame 10 is sealed by the moltoprene 21, but the second internal space A ₂ on the folding mirror 5 side has an optical cover 20. It is arranged so as to cover the upper part of the frame 10 so that dust and the like from the outside are hard to enter, but no moltoprene is provided.

The main reason that the scanning optical system becomes dirty is that, when the rotary polygon mirror 3 rotates, a flow of drawing air containing dust and toner like a vacuum cleaner occurs. Therefore, the first internal space A of the optical frame 10
₁ is sealed with moltoprene 21. Without internal space A ₂ of the second is heavy soil without sealing is to occur, also, there is also sufficient distance between the rotation drum D _1, further window 11 of the optical frame 10 with a width of about 6 to 7 mm,
Since there is also a labyrinth effect, dirt does not generally occur frequently. However, careless operation of the user,
For example, when toner is scattered in the vicinity of the optical path, when dew condensation occurs, or when the apparatus is placed in a smoking area, etc. The mirror 5 and the like must be structured so that maintenance such as cleaning work can be performed.

Therefore, a hinge portion 20c is provided on the cover 20 so that the first cover portion 20a on the rotating polygon mirror 3 is closed and the second cover portion 20b on the turning mirror 5 is closed.
It can be opened and closed. First cover part 20a
Is fastened to the upper end of the optical frame 10 by a screw 22. A locking claw 23 serving as a locking means is provided on the second cover portion 20b, and the second claw 23 is elastically locked to the locking portion 13 formed on the side wall 10a of the optical frame 10 by a so-called snap fit. The cover part 20b is fixed to the optical frame 10.

The initial assembly of the optical scanning device is the optical frame 10
Perform in a clean room to prevent dust from entering inside
The first internal space sealed with moltoprene 21
A ₁ Is maintained in an extremely clean state.

The second cover portion 20b of the cover 20 includes:
Since it is fixed by the snap fit by the locking claw 23 as described above, it is easy to open it for the purpose of cleaning maintenance or the like. On the other hand, since the first of the first cover portion 20a for closing the interior space A ₁ of the optical frame 10 is fixed to the optical frame 10 by screws, and thus is opened hard structure, a second cover portion for cleaning service When opening the first cover portion 20b,
a can be prevented from being opened.

The first and second cover portions 20a and 20b of the cover 20 are lockable with each other so as to be temporarily fixed in an open state when the second cover portion 20b is opened. Members 24 and 25 are provided. That is, as shown by a two-dot chain line in FIG. 2, the second cover portion 20b is turned over the first cover portion 20a,
When the lock members 24 and 25 are engaged, the second cover portion 20b can be fixed in an open state. When cleaning maintenance of the folding mirror 5 and the lens surface of the imaging lens system 4 and the like are performed in this manner, the working efficiency can be greatly improved.

It should be noted that, instead of using a flat plate member having an integral structure in which the first and second portions of the cover are integrated at a hinge portion,
The first and second cover portions may be separately assembled to the optical frame as separate flat plate members.
In this case, in order to release heat generated from the motor of the rotary polygon mirror, the first cover portion may be made of a metal plate having good heat dissipation.

As described above, if the first and second cover portions are separately provided, there is an advantage that the degree of freedom in selecting the respective materials is increased, and an optical scanning device having more excellent optical performance can be realized. In addition, since the second cover portion is completely removed and cleaning maintenance of the folding mirror and the like can be performed, work efficiency can be further improved.

[0047]

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

By opening only a part of the cover that closes the opening of the optical frame, it is possible to greatly improve the efficiency of work such as maintenance of the folding mirror and the lens surface of the imaging lens system.

As a result, it is possible to contribute to simplification of maintenance and the like and cost reduction of the optical scanning device and the image forming apparatus on which the optical scanning device is mounted.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic exploded perspective view showing a conventional example.

FIG. 4 is a sectional view showing the apparatus of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 3 Rotating polygon mirror 4 Imaging lens system 5 Folding mirror 10 Optical frame 13 Locking part 20 Cover 20a First cover part 20b Second cover part 20c Hinge part 21 Maltoprene 23 Locking claw 24, 25 Lock member

Claims (9)

[Claims] 1. A deflection scanning means for deflecting and scanning a light beam, an imaging optical means for forming an image of the light beam on an imaging surface via the deflection scanning means, and a first internal part including the deflection scanning means An optical frame having a space and a second internal space containing at least a part of the imaging optical means, and a cover for closing an opening of the optical frame, wherein the cover is provided on the first side of the optical frame. An optical scanning device comprising: a first cover portion that closes an internal space; and a second cover portion that can open and close the second internal space with the first cover member closed. . 2. The optical scanning device according to claim 1, wherein the image forming optical means includes at least one lens and a return mirror. 3. The optical scanning device according to claim 1, wherein the cover includes locking means for fixing the second cover portion to the optical frame by snap fitting. 4. The cover according to claim 1, wherein the cover has a hinge for pivotally connecting the second cover to the first cover. Optical scanning device. 5. The optical scanning device according to claim 1, wherein the first cover portion and the second cover portion are separate bodies. 6. The optical scanning device according to claim 1, wherein the first cover portion is made of metal. 7. The optical scanning device according to claim 1, further comprising a lock member for temporarily fixing the second cover portion in an open state. 8. The optical scanning device according to claim 1, further comprising sealing means for sealing between the first cover portion and the optical frame. 9. An image forming apparatus comprising: the optical scanning device according to claim 1; and a rotation unit configured to rotate an image forming surface on which the light beam forms an image.