JP2002116400A - Optical scanning optical unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning optical device constituted to prevent the occurrence of such trouble as to give rise to deformation and distortion in optical element parts of laser optical devices by the nonuniformity of the temperature in the device. SOLUTION: The optical scanning optical devices a1 to d1 of the image forming device having plural image carrying members a1 to d1 in order to form the images and the plural optical scanning optical devices a6 to d6 for irradiating the image carrying members a1 to d1 with scanning light in accordance with the image data consist of divided units and these units comprise first optical units au1 to du1 composed of the independent units and second optical units au2 to du2 provided with part of the optical element parts within a common housing 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly, to an optical scanning optical unit applied to a tandem type image forming apparatus having a plurality of image forming units arranged in parallel. About.

[0002]

2. Description of the Related Art Conventionally, a plurality of photosensitive drums are arranged side by side in an image forming section to form a color image, and a charging device, an exposure device, a developing device, a transfer device,
There is known a so-called tandem image forming apparatus in which cleaning devices are provided in this order so that an image corresponding to a color image can be obtained. As shown in FIG. 5, the image forming section A includes four substantially identical components.
The image forming stations a to d form a paper path 9
9 are juxtaposed. Reference numeral 97 denotes a paper feed cassette for storing the paper P, and 98 denotes a paper feed transport system for feeding the paper P to the transport path 99, and includes a paper feed roller and the like.

On the other hand, an image reading section B is provided on the image forming section A, and an automatic document feeder (ADF) C is mounted on the image reading section B and carried on the document table 110. The original is moved and scanned by an original scanning unit 111 including a first scanning unit 111a and a second scanning unit 111b disposed immediately below the original.
12 and form an image on a CCD (light conversion element) 113 via
The light image is output as an electric signal to an image processing device (not shown) of the image forming unit A, and subjected to image processing.

The four image forming stations a to d of the image forming section A are provided with photoconductive drums (image carriers) a1 to d1 which are driven to rotate.
A plurality of chargers a2 to d2 for uniformly charging the photosensitive drums a1 to d1, respectively, and a plurality of developing units for developing the electrostatic latent images formed on the photosensitive drums a1 to d1, respectively, around the photosensitive drums a1 to d1. Developing devices a3 to d3, a plurality of transfer rollers a4 to d4 for transferring the developed toner images on the photosensitive drums a1 to d1 to the sheet P, and removing the toner remaining on the photosensitive drums a1 to d1. A plurality of cleaning devices a
5 to d5 are arranged along the rotation direction of the photosensitive drums a1 to d1.

[0005] Laser optical devices a6 to d6 are provided above the photosensitive drums a1 to d1, respectively.
The laser optical devices a6 to d6 each include a semiconductor laser element (not shown) for emitting dot light modulated according to image data, and a polygon for deflecting a laser beam from the semiconductor laser element in the main scanning direction. A mirror (deflecting device), first and second fθ lenses for forming an image of the laser beam deflected by the polygon mirror on the surfaces of the photosensitive drums a1 to d1, and a first lens for bending an optical path in a predetermined direction. Optical element components such as first to third reflection mirrors are arranged.

A pixel signal corresponding to the black (Bk) component image of the color original image is input to the laser optical device a6, and a pixel corresponding to the cyan (C) component image of the color original image is input to the laser optical device b6. The signal is input, and the magenta (M) color image of the color original image is input to the laser optical device c6.
A pixel signal corresponding to the component image is input, and the yellow color (Y) of the color original image is input to the laser optical device d6.
Pixel signals corresponding to the component images are input.

As a result, an electrostatic latent image corresponding to the color-converted image data is formed on the surface of each of the photosensitive drums a1 to d1. The electrostatic latent image is developed by a developing device a3 containing black (Bk) toner, a developing device b3 containing cyan (C) toner, and a developing device b3 containing magenta (M) toner. The device image c3 is developed by the developing device d3 containing the yellow (Y) toner, and the original image data color-converted by the image forming unit A is converted into a toner image of each color on each of the photosensitive drums a1 to d1. Will be reproduced.

The toner images of the respective colors are sequentially superimposed on the transferred paper P by a transfer device (transfer rollers a4 to d4) to form a color image. Next, the transferred sheet P is sent to a fixing device 100 for fixing the toner image (color image). The fixing device 100 includes a heating roller 101 having a built-in heater and the heating roller 1.
The paper P on which the toner image has been transferred is heated by the heating roller 101, the toner image is fused and fixed on the paper P, and then the discharge roller 103 The paper is discharged onto a paper discharge tray 104.

[0009]

However, the internal temperature of such an image forming apparatus is often affected by the temperature (heat generation) of each component provided for image formation, and is also affected by the environmental temperature of the component. , May adversely affect other component parts in the vicinity. In particular, the fixing device 10
In the case of 0, since the toner image itself becomes extremely high because the toner image is heated and welded, the internal temperature of the image forming apparatus becomes non-uniform. Therefore, parts (optical element parts) constituting an optical system, such as lenses and reflection mirrors, provided in the laser optical devices a6 to d6 are thermally expanded and easily deformed or distorted.

In such a tandem type image forming apparatus, a color image is obtained by synthesizing component images obtained by four sets of laser optical devices in accordance with color components, thereby obtaining a color image. a6 ~
If the optical element components (lens, reflecting mirror, etc.) of d6 are deformed or distorted due to the influence of heat, a desired color image cannot be obtained, and thus measures have been required.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an optical scanning optical unit which does not cause a defect such as deformation or distortion of an optical element part of a laser optical device due to uneven temperature inside the device. The purpose is to provide. Another object of the present invention is to provide an optical scanning optical unit that can be easily assembled.

[0012]

According to the present invention, means for solving the above-mentioned problems are constituted as follows.

(1) An image forming apparatus comprising: a plurality of image carriers for forming an image; and a plurality of optical scanning optical devices for irradiating the image carriers with scanning light based on image data. The optical scanning optical device is composed of divided units, the configuration of which is a single optical unit and the second optical unit in which a part of optical element parts is provided in a common housing. And characterized in that:

According to this configuration, since a part of the optical components constituting the optical scanning optical device is configured in the common housing, the optical element components such as the lens and the reflection mirror provided in the second optical unit can be used. Since the temperature of the unit can be easily made uniform with respect to the influence of the temperature from the heat generating portion of the fixing device or the like, it is possible to prevent deformation and distortion of the optical element parts.

(2) Above the second optical unit,
A positioning member for positioning the plurality of first optical units is provided.

According to this configuration, since the positioning member for positioning the first optical unit is provided above the second optical unit, the first light is provided corresponding to the second optical unit. A scanning optical unit can be easily attached, and a plurality of optical scanning optical units are integrated as an optical scanning optical unit in a state where the position adjustment of each optical element component has been accurately performed in advance. It is not necessary to adjust the devices individually, and the adjustment to the devices can be easily performed.

(3) The second optical unit is provided with a blower for making the temperature of the optical element parts uniform.

According to this configuration, by providing the air blowing means in the second optical unit, the optical element parts such as the lens and the reflection mirror provided in the second optical unit are affected by the temperature of the fixing device and the like. Since each of them is maintained at a uniform temperature without receiving the same, deformation and distortion of the optical element parts can be prevented.

(4) The optical scanning optical device comprises a beam emitting means, a polygon mirror, a first fθ lens, a first reflection mirror, a second fθ lens, a second reflection mirror, and a third reflection mirror. Wherein the first optical unit comprises:
It has a beam emitting means, a polygon mirror, a first fθ lens lens, a first reflection mirror, and a second fθ lens, and the second optical unit has a second reflection mirror and a third reflection mirror. It is characterized by.

According to this configuration, after the laser beam emitted from the beam emitting means is deflected in the main scanning direction by the polygon mirror, the laser beam is passed through the lens and the mirror group.
An image is formed on the image carrier.

(5) The blower means is provided so as to form a suction device for sucking outside air and a blow passage for air taken in by the suction device, and to include the second optical unit. It is characterized by comprising a ventilation duct.

According to this structure, when the suction device is driven, the second optical unit is cooled by the outside air sucked into the air duct, so that the second reflection mirror and the third reflection mirror housed therein are cooled. The reflection mirror is maintained at a uniform temperature without being affected by the temperature of the fixing device or the like, whereby deformation and distortion of the optical element component can be effectively prevented.

(6) The air duct is formed by a partition member surrounding four sides, and the partition member optically connects the second optical unit and the first optical unit provided in the air duct. And a second opening for optically connecting the second optical unit to the image carrier.

According to this structure, the two openings allow
The first optical unit is optically connected to the second optical unit, and the second optical unit is optically connected to the image carrier.

(7) The suction device comprises a suction fan for sucking air and a filter for dust prevention.
The suction fan sucks outside air through the filter.

According to this structure, the suction device includes the suction fan and the dustproof filter. The suction fan sucks the outside air through the filter. No longer adheres.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical scanning optical unit according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a main configuration of a tandem-type digital color copying machine. A document table 2 on which a document is placed is provided at an upper portion of the copying machine main body 1. , Image reading unit 3, image forming unit 4, and paper feeding unit 5
Is provided. An automatic document feeder (hereinafter, referred to as ADF) 6 is mounted on the document table 2 so as to be openable and closable with respect to the document table 2 and has a predetermined corresponding positional relationship with respect to the document table surface. ing.

The image reading unit 3 is disposed immediately below the document table 2 and reciprocates in parallel along the lower surface of the document table 2 in a first scanning unit 71 and a second scanning unit 72.
, An optical lens 8, and a CCD line sensor 9 as a photoelectric conversion element. The ADF 6 is configured to read an image of the original sent to the original table 2 by the ADF 6. The image forming section 4 includes a plurality of image forming stations a to d.
-D have substantially the same configuration, and are arranged side by side sequentially from the upstream side of the paper transport path 10.

In the image forming stations a to d,
As the image carriers a1 to d1 that are driven to rotate, for example, photosensitive drums are provided. Each photosensitive drum a1 to d
A plurality of chargers a2 to d2 for uniformly charging the photosensitive drums a1 to d1, respectively, and a plurality of developing devices for developing the electrostatic latent images formed on the photosensitive drums a1 to d1 are respectively provided around the photosensitive drums a1 to d1. A plurality of devices a3 to d3, a plurality of transfer rollers a4 to d4 for transferring the developed toner images on the photosensitive drums a1 to d1 onto the paper P, and a plurality of transfer rollers for removing toner remaining on the photosensitive drums a1 to d1. Cleaning devices a5 to d
5 are arranged in this order along the rotation direction of the photosensitive drums a1 to d1.

Above the photosensitive drums a1 to d1, laser optical devices a6 to d as optical scanning optical devices are provided.
6 are provided. Each laser optical device a6
To d6, a semiconductor laser element (not shown) for emitting dot light modulated in accordance with image data, and a polygon mirror (deflecting device) 11 for deflecting a laser beam from the semiconductor laser element in the main scanning direction And a first fθ lens 1 for imaging the laser beam deflected by the polygon mirror 11 on the surfaces of the photosensitive drums a1 to d1.
2, a second fθ lens 13 and first, second, and third reflection mirrors 14, 15, and 16 that bend the optical path in a predetermined direction.

A pixel signal corresponding to a black (Bk) component image of a color original image is input to the laser optical device a6, and a cyan (C) component image of the color original image is input to the laser optical device b6. The pixel signal is input, and the magenta (M) color image of the color original image is input to the laser optical device c6.
A pixel signal corresponding to the component image is input. Then, pixel signals corresponding to the yellow (Y) component image of the color original image are input to the laser optical device d6. Thereby, an electrostatic latent image corresponding to the color-converted document image information is formed on each of the photosensitive drums a1 to d1.

Then, black (Bk) is applied to the developing device a3.
Is stored in the developing device b3, cyan (C) toner is stored in the developing device b3, magenta (M) toner is stored in the developing device c3, and yellow (Y) is stored in the developing device d3. The toner is stored in the photosensitive drum a
The electrostatic latent images on 1 to d1 are developed with toners of these colors. As a result, the document image information color-converted by the image forming unit 4 is reproduced as a toner image of each color.

The paper (recording medium) P loaded and stored in the paper feed cassette 51 is separated one by one into the paper feed unit 5 below the image forming unit 4 and directed toward the image forming unit 4. A paper feed mechanism is provided for supplying the pick-up roller 17.
A pair of registration rollers 19 disposed in front of the image forming unit 4 controls (adjusts) the sheet feeding timing of the sheets P separated and supplied one by one by the sheet feeding and conveying rollers 18 to form an image. It is carried into the unit 4.

A transfer conveyance belt 20 is provided in a paper conveyance path 10 provided below the image forming section 4, and the transfer conveyance belt 20 is substantially disposed between a driving roller 21 and a driven roller 22. The paper P is stretched so as to extend in parallel, and is driven to rotate in the direction indicated by the dashed arrow, electrostatically attracts the paper P sent from the paper supply unit 5 and transports it to the image forming stations a to d. The toner image of each color formed by the image forming unit 4 is
By the transfer devices (transfer rollers a4 to d4), the images are sequentially transferred onto the carried-in paper P to perform color synthesis.

Further, a fixing device 25 for fixing the toner image transferred and formed on the paper P is provided downstream of the transfer / conveyance belt 20. The fixing device 25 includes a heating roller 26 provided with a heater therein, and a pressure roller 27 pressed against the heating roller 26.
As a result, the toner image is fused and fixed on the paper P. Next, the sheet P on which the image has been fixed by the fixing device 25 is discharged to a discharge tray 29 by a discharge roller 28.

The copying machine body 1 having such a configuration is provided with
As shown in FIG. 4 to FIG. 4, a blowing unit 30 for equalizing the temperature in the laser optical devices a6 to d6 is provided, and the blowing unit 30 and the laser optical devices a6 to d6 are
The laser optical unit LU is configured integrally.

The laser optical unit LU includes a beam emitting means (not shown) using the upper partition member 31 as a lower base,
The first optical units au1 to du1 including the polygon mirror 11, the first fθ lens 12, the first reflection mirror 14, and the second fθ lens 15, the second reflection mirror 15, and the third reflection mirror 16 Including the second optical unit au2
du2.

The blowing means 30 comprises a suction device 33 and a blowing duct 34. The suction device 33 comprises a suction fan 35 for sucking outside air and a dustproof filter 36. The blowing duct (housing) 34 comprises The four sides are surrounded by partition members to form a ventilation path 37 for the air taken in by the suction device 33, and the ventilation path 37 is configured to include the second optical units au2 to du2.

Further, positioning ribs (positioning members) 39 for positioning the first optical units au1 to du1 are provided on the upper partition member 31 forming the upper surface of the air duct 38.
Are provided, and the first optical units au1 to du1 are provided.
Are engaged with the positioning ribs 39 so that the first optical units au1 to du1 are positioned at desired positions and optically connected to the second optical units au2 to du2 in a predetermined corresponding positional relationship. It is configured to be.

As shown in FIG. 1, the copying machine main body 1 is provided with an air inlet 41 corresponding to the air inlet 40 of the air duct 34 as the air blowing means 30 on the right side.
On the other hand, an exhaust port 43 is provided on the left side of the copying machine main body 1 corresponding to the air exhaust port 42 of the air duct 34. As described above, the air duct 30 is disposed so as to cross the inside of the copying machine main body 1 and is provided so as to communicate and connect the intake port 41 and the exhaust port 43 of the copying machine main body 1.

The first partitioning member 31 for optically connecting the first optical units au1 to du1 and the second optical units au2 to du2 is provided on the upper partition member 31 of the air duct 34.
The lower partition member 32 has the second optical units au2 to du2 and the photosensitive drums a1 to
A second opening 52 for optically connecting d1 is provided.

When the laser optical unit LU configured as described above is installed at a predetermined position in the copying machine body 1,
The beams bent by the third reflection mirrors 16 of the second optical units au2 to du2 are applied to the photosensitive drums a1 to al.
The light is projected on the exposed portion on the surface of d1.

In the air duct 34, there are provided second optical units au2 to du2 each including a first reflection mirror 14 and a second reflection mirror 15. Therefore,
When the suction fan 35 as a suction device is driven, outside air is taken in from the air inlet 41 provided on the right side of the copying machine main body 1 and the air inlet 40 of the air duct 30 (see FIG. 1). The second located in the duct 34
Second reflection mirror 15 of the optical units au2 to du2
After passing through the third reflection mirror 16, the air is discharged from the air outlet 42 of the air duct 34 and the air outlet 43 provided on the left side surface of the copying machine body 1 to the outside of the machine.

Thus, the second optical units au2 to au2
The second reflection mirror 15 and the third reflection mirror 16 included in the du2 are maintained at a uniform temperature without being affected by the temperature of the fixing device 25 or the like. Can be prevented.

Further, the laser optical units LU are assembled in a state where the positions of the respective optical element parts have been adjusted in advance and are integrated as the laser optical units LU. Does not need to be individually adjusted, and can be easily attached when assembling the image forming apparatus, and the assembling workability is extremely good.

[0047]

The present invention configured as described above has the following effects.

According to the first aspect of the present invention, a part of the optical parts constituting the optical scanning optical device is formed in the common housing, so that the optical element parts such as the lens and the reflection mirror provided in the second optical unit are provided. However, since the temperature of the unit can be easily made uniform with respect to the influence of the temperature from the heat generating portion of the fixing device or the like, deformation and distortion of the optical element component can be prevented.

According to the second aspect, the positioning member for positioning the first optical unit is provided above the second optical unit, so that the first optical unit is provided in correspondence with the second optical unit. The optical scanning optical unit can be easily attached, and the optical element parts are integrated as an optical scanning optical unit in a state where the position adjustment of each optical element component has been accurately performed in advance. There is no need to individually adjust the optical devices, and mounting adjustment to the devices can be easily performed.

According to the third aspect, by providing the second optical unit with the blowing means, the optical element parts such as the lens and the reflection mirror provided in the second optical unit can be controlled by the temperature of the fixing device or the like. Since they are maintained at a uniform temperature without being affected, deformation and distortion of the optical element component can be prevented.

According to the fourth aspect, after the laser beam emitted from the beam emitting means is deflected in the main scanning direction by the polygon mirror, the laser beam is passed through the lens and the mirror group.
An image is formed on the image carrier.

According to the fifth aspect, when the suction device is driven, the second optical unit is cooled by the outside air sucked into the air duct, so that the second reflection mirror and the third reflection mirror housed inside are cooled. The reflection mirror is maintained at a uniform temperature without being affected by the temperature of the fixing device or the like, whereby deformation and distortion of the optical element component can be effectively prevented.

According to the sixth aspect, by means of the two openings,
The first optical unit is optically connected to the second optical unit, and the second optical unit is optically connected to the image carrier.

According to the seventh aspect of the present invention, the suction device comprises a suction fan and a dustproof filter, and the suction fan sucks outside air through the filter. Etc. will not adhere.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main configuration of an image forming apparatus including an optical scanning optical unit according to an embodiment of the present invention.

FIG. 2 is a sectional view of the laser optical unit.

FIG. 3 is a cross-sectional configuration diagram of the main part.

FIG. 4 is a fragmentary perspective explanatory view of the main part.

FIG. 5 is a cross-sectional view illustrating a configuration of a main part of a conventional tandem image forming apparatus.

[Explanation of symbols]

 a1-d1-image carrier (photosensitive drum) a6-d6-optical scanning optical device (laser optical device) au1-du1-first optical unit au2-du2-second optical unit 11-polygon mirror 12-second 1 fθ lens 13 -second fθ lens 14 -first reflection mirror 15 -second reflection mirror 16 -third reflection mirror 30 -blower means 33 -suction device 34 -housing (blower duct) 35-suction Fan 36-Dustproof filter 37-Ventilation path 39-Positioning rib 51-First opening 52-Second opening

Claims (7)

[Claims] 1. An image forming apparatus comprising: a plurality of image carriers for forming an image; and a plurality of optical scanning optical devices for irradiating the image carriers with scanning light based on image data. The scanning optical device is composed of divided units, and the configuration of the unit is a first optical unit having a single unit configuration, and a second optical unit having a part of optical element parts provided in a common housing. And a light scanning optical unit. 2. The optical scanning optical unit according to claim 1, wherein a positioning member for positioning the plurality of first optical units is provided above the second optical unit. 3. The optical scanning optical unit according to claim 1, wherein the second optical unit is provided with a blower for making the temperature of the optical component uniform. 4. The optical scanning optical device includes a beam emitting unit, a polygon mirror, a first fθ lens, a first reflection mirror, a second fθ lens, a second reflection mirror, and a third reflection mirror. Wherein the first optical unit has a beam emitting means, a polygon mirror, a first fθ lens, a first reflection mirror, and a second fθ lens, and the second optical unit has a second reflection mirror 4. The optical scanning optical unit according to claim 1, further comprising a third reflecting mirror. 5. The air blowing means is provided so as to form a suction device for sucking outside air and an air blowing path for air taken in by the suction device, and to include the second optical unit. The optical scanning optical unit according to claim 3, comprising an air duct. 6. The air duct is formed by a partition member surrounding four sides, and the partition member optically connects a second optical unit and the first optical unit provided in the air duct. 6. A first opening for connection, and a second opening for optically connecting the second optical unit and the image carrier are formed. Optical scanning optical unit. 7. The apparatus according to claim 5, wherein the suction device comprises a suction fan for sucking air and a filter for dust prevention, and the suction fan sucks outside air through the filter. The optical scanning optical unit according to the above.