JPH1020608A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrate optical parts in a final stage as an optical scanner, to easily adjust each color image forming position, to restrain color slurring caused by secular change and thermal deformation and to improve image quality by setting a distance between image forming optical system arranged on both outer sides of plural image forming optical systems shorter than the double of the minimum of the distances between the image forming optical systems and photoreceptors corresponding to the image forming optical systems. SOLUTION: Final mirrors 33A to 33D are arranged at positions set symmetrical with respect to a plane passing the centers of four laser beams made incident on a light separation polygon mirror 32 and parallel with the optical axes of the laser beams and set so that the length of respective optical paths from a semiconductor laser array 25 to the photoreceptor drums 24A to 24D may be equal including relation to the reflection angles of the reflection surfaces 32A to 32D of the polygon mirror 32 based on the arraying positions of the drums 24A to 24D. The distance L1 between the mirrors 33A to 33D arranged on both outer sides is set shorter than the double of the distance L2 between the mirror 33A and the image forming position of the drum 24A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming a color image by forming images of different colors on a plurality of image carriers and sequentially transferring these images onto a moving transfer medium. Regarding the forming device, in particular,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus which facilitates adjustment of an image forming position of each color at the time of assembly and suppresses color shift due to aging and thermal deformation to improve the quality of a color image.

[0002]

2. Description of the Related Art As a color image forming apparatus such as a color copying machine or a color printer, for example, different colors are respectively provided on a plurality of photoconductors arranged in parallel in a moving direction of a transfer medium such as a recording paper or an intermediate transfer belt. A so-called tandem-type color image forming apparatus for forming a color image by forming these images sequentially and sequentially transferring the images to a moving transfer medium, respectively, is widely known.

FIG. 12 shows a general configuration of a tandem type color image forming apparatus. The color image forming apparatus is arranged in parallel in a recording paper conveying direction, and receives photosensitive drums 1A to 1A to form an electrostatic latent image on a surface thereof by being exposed to a laser beam by an optical scanning device described later.
D, chargers 2A to 2D such as corotrons for charging the photosensitive drums 1A to 1D, and Y obtained by subjecting R (red), G (green), and B (blue) color data to predetermined processing. (Yellow), M (magenta), C (cyan), and BK (black) optical scanning devices 3A to 3D that emit laser beams modulated based on image data;
A cylindrical mirror 4A for guiding the laser beams emitted from the optical scanning devices 3A to 3D to the photosensitive drums 1A to 1D
To 4D, developing machines 5A to 5D for developing the electrostatic latent images formed on the photosensitive drums 1A to 1D with Y, M, C, and BK toners, respectively, and the recording paper 6 to the photosensitive drums 1A to 1D. The photosensitive drums 1A to 1D are conveyed in a common tangential direction.
A transport belt 7 for transferring the toner images of the respective colors formed thereon onto the recording paper 6, cleaners 8A to 8D for removing the toner remaining on the photosensitive drums 1A to 1D, and a recording paper on which the transfer of each color has been completed. 6 has a fixing roll 9 for fixing the transferred image.

FIG. 13 shows an optical scanning device 3A. Here, the optical scanning devices 3B to 3D have the same configuration as the optical scanning device 3A, and thus the description thereof will be omitted. The optical device 3A collects a laser diode 11 that emits a laser beam modulated by being controlled by a light emission time control circuit 10 based on image data of a predetermined color, and a laser beam that is emitted from the laser diode 11. A collimator lens 12 that emits light,
A cylindrical lens 13 for condensing a laser beam diffused from a focal point, and a polygon mirror 14 for reflecting and deflecting the laser beam passing through the cylindrical lens 13
And a fθ lens 15 for converging the deflection beam reflected and deflected by the polygon mirror 14 in the main scanning direction and scanning the exposure line of the photosensitive drum 1A at a constant speed. An irradiation position detection sensor 16 is provided on the side of the photosensitive drum 1A following the exposure line, and the timing of writing an image to the photosensitive drum 1A is controlled based on the output.

In such a configuration, the optical scanning device 3A
To 3D emit laser beams modulated based on the image data of Y, M, C, and BK, and charge the chargers 2A to 2D in advance.
The photosensitive drums 1A to 1D that are rotated by being charged are exposed to light to form electrostatic latent images on the surfaces of the photosensitive drums 1A to 1D. This electrostatic latent image is developed with toner of each color in the developing machines 5A to 5D, and is moved to a transfer point to the recording paper 6. At the same time, the recording paper 6 is sent to the transfer points of the photoconductor drums 1A to 1D at a predetermined timing by the conveyance belt 7, and the toner images of the respective colors formed on the photoconductor drums 1A to 1D are sequentially recorded on the recording paper 6. Transcribed. The transferred recording paper 6 is conveyed to a fixing roll 9 where the transferred image is fixed.

Incidentally, in such a general tandem type color image forming apparatus, since a plurality of optical scanning devices corresponding to a plurality of photosensitive drums respectively perform laser beam exposure, the size of the apparatus is increased. In addition, there was a problem that the cost increased.

Therefore, recently, a color image forming apparatus for reducing the size and cost by sharing optical components for a plurality of laser beams for exposing a plurality of photosensitive drums is disclosed in, for example, JP-A-6-286226. Proposed by the gazette.

FIG. 14 shows the above-described color image forming apparatus. This color image forming apparatus has a semiconductor laser array (not shown) for emitting four laser beams.
A polygon mirror 17 for commonly reflecting and deflecting four laser beams emitted from the semiconductor laser array; a reflection mirror 18 for guiding the four deflected beams reflected and deflected by the polygon mirror 17 in a predetermined direction; An fθ lens 19 for converging the four laser beams reflected at 18 in the main scanning direction to scan the exposure lines of the photosensitive drums 1A to 1D at a constant speed, and a prism having four incident surfaces of different angles A prism-type reflecting mirror 20 for separating the four laser beams passing through the fθ lens 19 in a direction corresponding to the arrangement positions of the photosensitive drums 1A to 1D, and a prism-type reflecting mirror 20. Mirrors 21A to 21A that guide the four laser beams separated by the laser beams to the corresponding photosensitive drums 1A to 1D, respectively.
F, and cylindrical lenses 22A to 22D for focusing the four laser beams reflected by the reflection mirrors 21A to 21F in the sub-scanning direction, respectively.

Here, as described above with reference to FIG. 12, the related devices such as the cleaner and the developing machine are arranged between the photosensitive drums 1A to 1D.
The distance between each of the photoconductive drums A to 1D is determined.
1A to 21F are arranged. Therefore, the distance between the outermost reflecting mirror 21A, the distance L ₁ between 21F, most imaging position of the outer reflecting mirror 21A and the photosensitive drum 1A L
It is very large compared to ₂ .

In this configuration, when four laser beams modulated based on Y, M, C, and BK image data are emitted from the semiconductor laser array, they are commonly reflected and deflected by the polygon mirror 17, The light enters the prism-type reflecting mirror 20 via the reflecting mirror 18 and the fθ lens 19, and is separated therefrom in a direction corresponding to the arrangement position of the photosensitive drums 1A to 1D. The four light beams thus separated are respectively reflected by the reflection mirrors 2 leading to the corresponding photosensitive drums 1A to 1D.
1A to 21F, reflected by the cylindrical lens 22A
The photosensitive drums 1A to 1D, which are previously charged and rotate after passing through to 22D, are exposed to form electrostatic latent images on the surfaces of the photosensitive drums 1A to 1D.

[0011]

However, according to the conventional color image forming apparatus, the distance between the outermost reflecting mirrors is much longer than the distance between the outermost reflecting mirrors and the imaging position of the photosensitive drum. Since a cylindrical lens and a reflection mirror, which are imaging optical systems, are located near the photosensitive drum, it is difficult to design these imaging optical systems together with other scanning optical systems. For this reason, unless each optical component is incorporated in an actual device to configure an optical scanning device in the actual device, the adjustment of the image forming position of each color cannot be performed, and there is a disadvantage that the adjustment operation becomes complicated. In addition, since the support member of each optical component causes a temporal variation and a thermal variation independently, there is a disadvantage that an image forming position of each color is shifted and a color shift occurs. Further, when the distance between the outermost reflecting mirrors is large, there is a problem that the image forming apparatus is easily affected by an imaging position shift due to thermal deformation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a color image forming apparatus in which the distance between the last optical component of the optical scanning device and the photosensitive member is increased so that the last optical component can be integrated as an optical scanning device. It is to provide.

Another object of the present invention is to provide a color image forming apparatus which facilitates adjustment of an image forming position of each color and suppresses color shift due to aging or thermal deformation to improve the quality of a color image. It is to be.

[0014]

SUMMARY OF THE INVENTION In view of the above problems, the present invention integrates a final optical component as an optical scanning device to facilitate adjustment of an image forming position of each color, and also to prevent temporal variation and thermal deformation. A laser light source that emits a plurality of laser beams according to the number of photoconductors and a deflection that commonly deflects the plurality of laser beams emitted from the laser light source in order to suppress color shift and improve the quality of a color image. Means, separation means for separating the plurality of laser beams deflected by the deflection means in a direction corresponding to the arrangement position of the plurality of photoconductors, and imaging of the plurality of laser beams separated by the separation means on the plurality of photoconductors With a plurality of imaging optical systems leading to the position, the distance between the imaging optical systems arranged on both outer sides of the plurality of imaging optical systems,
An object of the present invention is to provide a color image forming apparatus configured to be smaller than twice the minimum distance between a plurality of imaging optical systems and the corresponding photoconductors.

It is preferable that the laser light source, the deflecting means, the separating means, and the plurality of imaging optical systems have an integrated structure.

Preferably, the plurality of imaging optical systems have an emission window unit having a plurality of emission windows for guiding a plurality of laser beams to imaging positions of a plurality of photoconductors. A configuration supported by the unit is preferred.

The laser light source, the deflecting means, the separating means, and the plurality of imaging optical systems are integrated into a housing to form an optical unit, and the emission window unit is a part of the housing. preferable.

Preferably, the laser light source emits a plurality of laser beams each having a plurality of different imaging positions on a plurality of photosensitive members.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a color image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a color image forming apparatus according to a first embodiment of the present invention. This color image forming apparatus
4 modulated based on Y, M, C, and BK image data
An optical scanning device 23 that emits four laser beams, and photoconductor drums 24A to 24D that form an electrostatic latent image on the surface by receiving exposure of the four laser beams emitted from the optical scanning device 23 are provided. It is configured.

The optical scanning device 23 includes a semiconductor laser array 25 that emits four parallel laser beams adjacent to each other, and a collimator lens that converts the four diffused laser beams emitted from the semiconductor laser array 25 into parallel beams. 26, a cylindrical lens 27 for focusing the four laser beams passing through the collimator lens 26 in the sub-scanning direction, and a reflecting mirror 28 for reflecting the four laser beams passing through the cylindrical lens 27 in a predetermined direction. A polygon mirror 29 that reflects and deflects the four laser beams reflected by the reflection mirror 28 and a photoreceptor drum 2 that focuses the four laser beams reflected and deflected by the polygon mirror 29 in the main scanning direction and the sub-scanning direction, respectively.
Fθ for scanning the exposure lines of 4A to 24D at a constant speed
A lens 30, a reflecting mirror 31 that reflects four laser beams passing through the fθ lens 30 in a predetermined direction, and four laser beams reflected by the reflecting mirror 31 according to the arrangement positions of the photosensitive drums 24A to 24D. And the four laser beams separated by the light separating polygonal mirror 32 correspond to the corresponding photosensitive drums 24A.
Mirrors 33A to 33D leading to the laser beams 24A to 24D and cylindrical lenses 34A to 34C for focusing the laser beams reflected by the final mirrors 33A to 33D in the sub-scanning direction.
4D and a housing 35 that houses and integrally supports these optical components. Here, instead of using the cylindrical lenses 34A to 34D, a configuration may be adopted in which a laser beam is focused in the sub-scanning direction using cylindrical mirrors as the final mirrors 33A to 33D. This is the same in other embodiments described later.

FIG. 2 shows the light separating polygon mirror 32. The light separating polygon mirror 32 passes through the center of the four incident laser beams, and is located at a position symmetrical with respect to a plane parallel to the optical axis of these laser beams, and at predetermined positions different from each other with respect to the incident direction of the laser beams. The two laser beams are arranged at two angles, and have reflecting surfaces 32A to 32D that reflect the four incident laser beams in four different directions. The reflection angle of the reflection surfaces 32A to 32D depends on the arrangement position of the photosensitive drums 24A to 24D.
The optical path lengths from the semiconductor laser array 25 to the photosensitive drums 24A to 24D are set to be equal to each other including the positions of to 33D.

The final mirrors 33A to 33D pass through the centers of the four laser beams incident on the light separating polygon mirror 32 and are symmetric with respect to a plane parallel to the optical axis of the laser beams.
In addition, based on the arrangement positions of the photoconductor drums 24A to 24D, the semiconductor laser array 25 transmits the photoconductor drums 24 including the relationship with the reflection angles of the reflection surfaces 32A to 32D of the polygon mirror 32.
They are arranged at positions set so that the optical path lengths from A to 24D are equal. Also, the final mirror 33A disposed on both outer sides, the distance L ₁ between 33D, is smaller than twice the distance L ₂ between the imaging position of the final mirror 33A and the photosensitive drum 24A.

The photosensitive drum 24A~24D is to design a transfer efficiency to the transfer medium at the transfer portion to 100%, since the need for cleaner and a waste toner reservoir, is arranged at a small center distance L ₃ ing.

FIGS. 3A and 3B show the optical scanning device 23.
2 is a developed view in a plane including the optical axis of the scanning optical system. Here, (a) corresponds to a development in the sub-scanning direction,
The laser beam emitted from the semiconductor laser array 25 is focused on a polygon mirror 29 by a collimator lens 26 and a cylindrical lens 27, and then fθ
The reflecting surfaces 32A to 3A of the light separating polygon mirror 32 by the lens 30
The light is focused on 2D, and further focused on the photosensitive drum 24A by the cylindrical lens 34A. That is, in the sub-scanning direction, the emission surface of the semiconductor laser array 25 and the polygon mirror 29, and the polygon mirror 29 and the light separating polygon mirror 3
2. Furthermore, the light separating polygon mirror 32 and the drum surface of the photosensitive drum 24A are in an optically conjugate relationship. On the other hand, (b) corresponds to the development in the main scanning direction, and the semiconductor laser array 25
Is emitted from the collimator lens 26.
, And is then imaged on the photosensitive drum 24A by the fθ lens 30.

In the above configuration, when four laser beams modulated based on the image data of Y, M, C, and BK are emitted from the semiconductor laser array 25, they are converted into parallel beams by the collimator lens 26. Are focused in the sub-scanning direction by a cylindrical lens 27, and further reflected and deflected by a polygon mirror 29. The four reflected and deflected beams are respectively focused in the main scanning direction and the sub-scanning direction by the fθ lens 30 and guided to the light separating polygon mirror 32 by the reflecting mirror 31, where the photosensitive drums 24A to 24A are formed.
It is separated in the direction according to the arrangement position of 24D. The four separated light beams are respectively applied to the corresponding photosensitive drums 24.
The photosensitive drums 24A to 24D, which are reflected by the reflecting mirrors 33A to 33D and lead to the rotating photosensitive drums 24A to 24D through the cylindrical lenses 34A to 34D, are exposed to light and are exposed to electrostatic charges on the surfaces of the photosensitive drums 24A to 24D. Form a latent image.

In the first embodiment, for example, the array distance of the semiconductor laser array 25 is 250 μm, the focal length of the collimator lens 26 is 28.2 mm, the focal length of the cylindrical lens 27 is 225.2 mm, and fθ The distance to the lens 30 is 100 mm, f
The distance from the θ lens 30 to the light separating polygon mirror 32 is 100
mm, the light separating polygon mirror 32 to the cylindrical lens 34
The distance from A to 34D is 85 mm, the distance from the cylindrical lenses 34A to 34D to the photosensitive drums 24A to 24D is 106 mm, and the photosensitive drum 24A
The laser beam diameter on ２４24D is 50 μm. Also,
Distance L ₃ between the centers of the photosensitive drum 24A~24D 2
Has become 5 mm, a distance L ₂ between the most final mirror 33A that outside are arranged, the distance L ₁ between 33D is 75 mm, the imaging position of the final mirror 33A and the photoreceptor drum 24A is a 140.2mm Become.

As described above, according to the color image forming apparatus of the present embodiment, the final mirrors 33 arranged on both outer sides are provided.
A, the distance L ₁ between 33D is smaller than twice the distance L ₂ between the imaging position of the final mirror 33A and the photosensitive drum 24A, the final mirror 33 an imaging optical system
A to 33D and the cylindrical lenses 34A to 34D can be integrated with other scanning optical systems, and the adjustment of the image forming position of each color at the time of assembling the optical scanning device can be facilitated.

FIG. 4 shows a method of adjusting the image forming position of each color of the optical scanning device 23. The image forming position has light receiving elements 36A to 36D such as CCD sensors arranged in advance at the same interval as the distance between the photosensitive drums. The optical scanning device 23 is opposed to the adjusting jig 37 in a predetermined positional relationship, and the light receiving elements 36A to 36D
The adjustment can be easily performed only by irradiating four laser beams based on Y, M, C, and BK from the optical scanning device 23. The adjustment is performed by changing the mounting angle of the mirror or the lens of the optical scanning device 23, and after the adjustment, it is merely required to face the photosensitive drum with a predetermined positional relationship in the actual machine.

Further, since a plurality of optical components constituting the optical scanning device 23 are supported by a common support member, color shift due to aging and thermal deformation can be suppressed.

In the above embodiment, the light separating polygon mirror 32 is used as a separating means for separating the four laser beams in a direction corresponding to the arrangement positions of the photosensitive drums 24A to 24D. A prism-type reflecting mirror combining a prism having four incident surfaces symmetrically arranged at an angle and four mirrors, a diffraction grating array, a lens array, a concave mirror array, or the like may be used. In addition, each photosensitive drum 2
4A to 24D may be scanned with a plurality of laser beams close to each other to increase the scanning speed and increase the resolution.

FIG. 5 shows a color image forming apparatus according to a second embodiment of the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals and symbols, and therefore, duplicate description will be omitted. In this color image forming apparatus, the photosensitive drums 24A to 24D arranged in an arc on the outer periphery of the intermediate transfer drum 38 are exposed and scanned by four laser beams based on Y, M, C, and BK. 24
The toner images of the respective colors on A to 24D are transferred as full-color images onto recording paper 39 using an intermediate transfer drum 38 and a transfer roll 40. Thus, even when the photosensitive drums 24A to 24D are arranged in a curved line, the direction of the separated laser beam is changed by changing the reflection angles of the reflecting surfaces 32A to 32D of the light separating polygon mirror 32, and the final mirror 33A is changed. ~ 33D, cylindrical lens 34A ~ 3
By moving the position of 4D so that each optical path length does not change, an image can be formed on each of the drum surfaces of the photosensitive drums 24A to 24D. The distance L between the final mirror 33A disposed on both outer sides, the distance L ₁ between 33D, the final mirror 33A and the imaging position of the photosensitive drum 24A
Less than 2 times the ₂ is set. Even in such a configuration,
The same effect as in the first embodiment can be obtained.

FIG. 6 shows a third embodiment of the present invention.
A color image forming apparatus is shown. In this figure,
The same parts as those in 1 have the same reference numerals and symbols.
Therefore, duplicate description will be omitted. This color image forming apparatus
Are unpaired with four reflecting surfaces at different angles
The four light beams are separated by a light separating polygon mirror 41 having a nominal shape, and
Four final mirrors 3 arranged on the reflection side of separation polygon mirror 41
Each of the four laser beams separated by 3A to 33D
Configuration to lead to corresponding photoconductor drums 24A to 24D
Have been. Here, the final mirrors 3 arranged on both outer sides
Distance L between 3A and 33D₁Is exposed to the final mirror 33A
Distance L from the image forming position of body drum 24A _TwoThan twice
It is set small. Even in such a configuration, the first actual
An effect similar to that of the embodiment can be obtained. Also light
Distance L from separating polygon 41 to final mirror 33D₁’
Is also the image forming position of the final mirror 33A and the photosensitive drum 24A.
Distance L between_TwoMust be smaller than twice
Is preferred.

In the first to third embodiments described above, the distance L ₁ between the final mirrors disposed on both outer sides is determined by the distance between the plurality of final mirrors and the imaging position of the photosensitive drum. becomes smaller than twice the minimum distance L ₂ distance of spacing of the four laser beams for exposure scanning of the photosensitive drum 24A~24D becomes narrower, also light separating polygon mirror 32,4
Since the total length in the main scanning direction is shorter than the scanning amount of the laser beam that scans both sides in the main scanning direction, it is difficult to support the light separating polygonal mirror 32 without interrupting each optical path. For example, the laser beam can be supported by an elongated support member extending in the main scanning direction while avoiding the optical path of the laser beam. However, it is difficult to stably support the laser beam at a precise position with sufficient strength.

FIG. 7 shows a color image forming apparatus according to a fourth embodiment of the present invention which solves such a problem. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals and symbols, and duplicate description will be omitted. This color image forming apparatus forms a part of a housing 35, and has a configuration in which the light separation polygon mirror 32 is supported on an emission window support member 43 that supports an emission window described later.

FIG. 8 shows the emission window support member 43. The emission window support member 43 has four emission windows 44A to 44D through which a laser beam based on Y, M, C, and BK passes to prevent toner and dust from entering the optical scanning device 23. The light separating polygon mirror 32 is supported between the windows 44B, 44B.

With such a configuration, the light separating polygon mirror 32 can be stably supported at an accurate position with sufficient strength without interrupting the optical path of each laser beam.

Further, as shown in FIG.
For a color image forming apparatus in which 4A to 24D are arranged in a curved line along the outer periphery of the intermediate transfer drum 38, the light separating polygon mirror 32 may be supported on the exit window support member 43 in the same manner.

Further, when the light separating polygon mirror 32 is unavoidably separated from the exit window support member 43 due to restrictions on the design of the lens and mirror, as shown in FIG. It may be supported via a mirror support member 45, or may be fixed on a convex surface 43A formed on the exit window support member 43 as shown in FIG.

[0040]

As described above, according to the color image forming apparatus of the present invention, the distance between the image forming optical systems arranged on both outer sides of the plural image forming optical systems is changed by the plurality of image forming optical systems. The optical components at the final stage can be integrated as an optical scanning device, and the adjustment of the image forming position of each color is facilitated. At the same time, it is possible to improve the image quality of a color image by suppressing color shift due to aging fluctuation and thermal deformation.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a light separating polygon mirror according to the first embodiment.

FIG. 3 is a plan view showing a scanning optical system according to the first embodiment.

FIG. 4 is an explanatory diagram showing a method of adjusting an image forming position of each color according to the first embodiment.

FIG. 5 is an explanatory view showing a second embodiment of the present invention.

FIG. 6 is an explanatory view showing a third embodiment of the present invention.

FIG. 7 is an explanatory view showing a fourth embodiment of the present invention.

FIG. 8 is an explanatory view showing an emission window support member according to a fourth embodiment.

FIG. 9 is an explanatory view showing a fifth embodiment of the present invention.

FIG. 10 is an explanatory view showing a sixth embodiment of the present invention.

FIG. 11 is an explanatory view showing a seventh embodiment of the present invention.

FIG. 12 is an explanatory view showing a general tandem type color image forming apparatus.

FIG. 13 is an explanatory diagram showing the optical scanning device in FIG.

FIG. 14 is an explanatory view showing a conventional color image forming apparatus.

[Explanation of symbols]

 Reference Signs List 1A to 1D Photoreceptor drum 2A to 2D Charger 3A to 3D Optical scanning device 4A to 4D Cylindrical mirror 5A to 5D Developing machine 6 Recording paper 7 Transport belt 8A to 8D Cleaner 9 Fixing roll 10 Light emitting time control circuit 11 Laser diode 12 Collimator Lens 13 Cylindrical lens 14 Polygon mirror 15 fθ lens 16 Irradiation position detection sensor 17 Polygon mirror 18 Reflection mirror 19 fθ lens 20 Prism reflection mirror 21A to 21F Reflection mirror 22A to 22D Cylindrical lens 23 Optical scanning device 24A to 24D Photosensitive drum 25 Semiconductor laser 26 Collimator lens 27 Cylindrical lens 28 Reflecting mirror 29 Polygon mirror 30 fθ lens 31 Reflecting mirror 32 Light separating polygon mirror 32A-32D Reflecting surface 33A-33 Final mirror 34A to 34D Cylindrical lens 35 Casing 36A to 36D Light receiving element 37 Image forming position adjusting jig 38 Intermediate transfer drum 39 Recording paper 40 Transfer roll 41 Light separation polygon mirror 42A to 42D Cylindrical mirror 43 Exit window support member 43A Convex surface 44A to 44D Emission window 45 Polygon mirror support member

Claims (6)

[Claims] An image of different colors is formed on a plurality of photoconductors arranged in a direction of movement of a transfer medium, and these images are sequentially transferred on the transfer medium to be moved at a predetermined timing. In a color image forming apparatus for forming an image, a laser light source that emits a plurality of laser beams according to the number of the plurality of photoconductors, and a deflecting unit that commonly deflects the plurality of laser beams emitted from the laser light source Separating means for separating the plurality of laser beams deflected by the deflecting means in a direction corresponding to the arrangement position of the plurality of photosensitive members; and separating the plurality of laser beams separated by the separating means into the plurality of laser beams. A plurality of imaging optical systems for guiding the imaging position of the photoreceptor; and a distance between the imaging optical systems arranged on both outer sides of the plurality of imaging optical systems. Color image forming apparatus for image forming optical system of the characterized it that is configured to set smaller than twice the minimum distance of the distance between the photosensitive member corresponding. 2. The color image forming apparatus according to claim 1, wherein the laser light source, the deflecting unit, the separating unit, and the plurality of imaging optical systems have an integrated configuration. 3. The image forming optical system according to claim 1, wherein the plurality of image forming optical systems include an output window unit having a plurality of output windows for guiding the plurality of laser beams to the image forming positions of the plurality of photoconductors. Color image forming apparatus. 4. A color image forming apparatus according to claim 3, wherein said separation means is supported by said exit window unit. 5. An optical unit, wherein the laser light source, the deflecting unit, the separating unit, and the plurality of imaging optical systems are integrated in a housing to form an optical unit. The color image forming apparatus according to claim 3, wherein the color image forming apparatus is a part. 6. The laser light source according to claim 1, wherein each of the plurality of laser beams emits a plurality of laser beams having a plurality of different imaging positions on the plurality of photoconductors. The color image forming apparatus according to the above.