JP2002311694A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make suspended toner coming out from an image formation part hardly stick to the dustproof member of an optical scanner on a lower side. SOLUTION: Two dustproof glasses 9 are respectively fixed at a cover 17 covering the upper part of the optical scanner 7 in a posture by which right and left planes are made nearly in parallel in a gravity direction (in an up-and- down direction in a figure 1). Thus, even though the suspended toner coming out from developing devices 53, 54, 63 and 64 falls down, the dustproof glasses 9 and 9 of wiring parts 11 and 12 are set in a standing state in which the right and left planes are both in the posture nearly in parallel in the gravity direction, and the toner fallen on the glass surface of the dustproof glass 9 slides down on the glass surface by gravity, so that it does not accumulated on the dustproof glass 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming section having a developing section for developing a latent image formed on the surface of a photoreceptor with toner, and a light passing through a dustproof member on the surface of the photoreceptor. The present invention relates to an image forming apparatus including an optical scanning device that irradiates the surface of a photoconductor by irradiating the same.

[0002]

2. Description of the Related Art For example, in a color image forming apparatus, 2
Some photoconductors and an image forming unit having a developing unit corresponding to each photoconductor are formed integrally with an optical scanning device that exposes the surface of the photoconductor with light. In the case of an image forming apparatus having such a configuration, an optical scanning device is generally arranged below the image forming unit. In such an image forming apparatus, the latent image is formed by irradiating the photoreceptor with light corresponding to the color of the image to be formed by the two writing units of the optical scanning device, and the latent image is developed by the developing unit. The toner image is developed by toner, and the color toner image is superimposed on the intermediate transfer belt to form a color image.

[0003]

However, when an optical scanning device that emits light toward each photoreceptor of the image forming unit is arranged below the image forming unit using the toner as described above. When the floating toner that comes out of the image forming unit falls on and accumulates on the dust-proof glass portion, which is a dust-proof member of the optical scanning device, the toner blocks light (exposure) that passes through the dust-proof glass. As a result, there is a problem that the toner does not adhere to the image portion corresponding to the portion where the light is blocked, and a white spot image occurs in which the white spot is lost. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to prevent floating toner coming out of an image forming unit from adhering to a dustproof member of an optical scanning device.

[0004]

In order to achieve the above object, the present invention provides a photosensitive member and a developing section for developing a latent image formed on the surface of the photosensitive member with toner to form a visible image. The image forming unit has a light-transmitting surface under the image forming unit, and the surface of the photosensitive member is exposed to light by irradiating light to the surface of the photosensitive member through a dust-proof member formed of a plane that is parallel to each other and transmits light. In the image forming apparatus provided with the optical scanning device, the dustproof member is arranged in a posture in which the plane is substantially parallel to the direction of gravity. It is more effective when the image forming unit is provided with two photoconductors and a developing unit corresponding to each of the photoconductors. Further, it is more effective if the dustproof member is formed of a thin light transmitting sheet.

Further, in any of the above image forming apparatuses, a toner guiding member made of a conductive metal may be provided near the dustproof member, and the toner guiding member may be grounded. A large number of peaks may be formed at the tip of the toner guiding member along the optical scanning direction. Further, in the image forming apparatus provided with the toner guide member, a holding member for holding the dustproof member in contact with a portion of the dustproof member other than the place where light is transmitted is provided, and the holding member has conductivity. The holding member is formed of a metal, and a toner guiding portion functioning as the toner guiding member is formed at a position near the dustproof member, and light passing through the dustproof member and exposing the photosensitive member is exposed on a plane of the dustproof member. It is preferable to dispose the optical scanning device with respect to the photoreceptor so that the light scanning device passes through at approximately 45 degrees to the photosensitive member.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration of an image forming unit and an optical scanning device included in a two-drum color image forming apparatus as an embodiment of the image forming apparatus according to the present invention.
3 is an overall configuration diagram showing the configuration of the two-drum color image forming apparatus, and FIG. 3 is a plan view showing the configuration of the optical scanning device of FIG. 1 with the lid opened. The two-drum color image forming apparatus shown in FIG. 2 is composed of two photoconductors 51 and 61 and a developing unit disposed corresponding to each of the photoconductors 51 and 61. Developing devices 53, 54 and 6 for developing the latent image to be formed into a visible image by developing with a toner
3 and 64 are provided. Then, the first image forming unit 5 and the second image forming unit 6
A lower surface is provided with two writing portions 11 and 12, and both surfaces which transmit light emitted from the laser diode units 13 and 14 shown in FIG. 3 which are light emitting portions of the writing portions 11 and 12 are parallel to each other. The optical scanning device 7 irradiates and exposes the two photoconductors 51 and 61 with light passing through dustproof glasses 9 and 9 shown in FIG.

This two-drum color image forming apparatus is shown in FIG.
As shown in FIG. 2, the paper feed unit 2 is disposed immediately below the optical scanning device 7. The paper feed unit 2 includes a paper feed cassette 21 that can be attached to and detached from the apparatus main body 1. The paper feeding unit 2 can be further provided with another paper feeding cassette if necessary. Further, at the upper part of the apparatus main body 1, there is formed a paper discharge storage section 3, and the paper after an image is formed thereon and passed through the fixing device 19 is discharged by a paper discharge device 31 composed of a pair of rollers. It has become so. Above the first image forming unit 5 and the second image forming unit 6, a belt-shaped intermediate transfer belt 4 is mounted between left and right rollers so as to be rotatable in the direction of arrow A.

The first image forming section 5 is provided with the above-described drum-shaped photoreceptor 51, and the second image forming section 6 is provided with a photoreceptor 61, around which the photoreceptor 51 is provided. , 61 for charging the surfaces of, 61
And the developing devices 53, 54, 63 and 64 described above, in which the electrostatic latent images formed by exposing the surfaces of the photoconductors 51 and 61 by the optical scanning device 7 are made visible by toner of each color.
And cleaning devices 55 and 65 for removing and collecting the toner remaining on the photoconductors 51 and 61 after the transfer of the toner image to the paper, respectively. The developing device 53 is a developing device for magenta (M), and the developing device 5
Reference numeral 4 denotes a developing device for cyan (C). The developing device 63 is a developing device for yellow (Y).
Reference numeral 4 denotes a developing device for black (BK). A transfer device (transfer roller) 8 for transferring the toner image carried on the intermediate transfer belt 4 to a sheet is provided on the right side of the intermediate transfer belt 4 in FIG. Further, on the left side of the intermediate transfer belt 4 in the figure, there is provided an intermediate transfer cleaning device 41 for removing and collecting the toner remaining on the surface of the intermediate transfer belt 4 after the transfer of the toner image onto the paper.

In the image forming process of the two-drum color image forming apparatus, the intermediate transfer belt 4 rotates twice (two rotations), and
To form one color image. The color image forming process of the two-drum color image forming apparatus firstly includes the first
The magenta (M) toner image is developed by the image forming section 5 into the developing device 53.
And transfer it to the intermediate transfer belt 4. next,
The yellow (Y) toner image is developed by the developing device 63 in the second image forming unit 6 and is transferred onto the intermediate transfer belt 4 so as to overlap the magenta toner image. When the intermediate transfer belt 4 on which the magenta and yellow toner images have been transferred makes one revolution, the developing operation of the next color is started, and the first image forming unit 5 develops the cyan toner image with the developing device 54. The toner image is transferred so as to be superimposed on the toner image on the intermediate transfer belt 4, and finally, the black toner image is developed by the developing device 64 of the second image forming unit 6, and is developed.
Is transferred so as to be superimposed on the toner image.

The four-color superimposed toner image transferred onto the intermediate transfer belt 4 is fed from the paper feeding unit 2 at a predetermined timing, and the timing is adjusted by the registration rollers 23 to form a paper sheet fed. The image is transferred by the transfer device 8. After the transfer of the toner image, the intermediate transfer belt 4
The toner remaining on the intermediate transfer cleaning device 41
Is removed and recovered. In addition, a transfer device (transfer roller)
Reference numeral 8 denotes a point at which the latent image formed in the first rotation on the intermediate transfer belt 4 is separated from the intermediate transfer belt 4 when the latent image is developed into magenta and yellow, and thereafter, cyan and black are developed. After the four color toners are developed, the toner comes into contact with the intermediate transfer belt 4.

The sheet on which the four-color superimposed toner image has been transferred is subjected to a fixing process by the fixing device 19, and is disposed downstream of the sheet conveying direction when forming a single-sided image in which an image is formed on only one side. The paper is discharged onto the paper storage unit 3 by the paper discharge device 31 and stored therein.
Further, when forming a two-sided image in which images are formed on both sides of the sheet, the sheet on which the toner image of the four-color superposition has been transferred is branched by the branching unit 20 immediately after passing through the fixing device 19, and is directed toward the sheet discharging device 31. Instead, the sheet is once conveyed to the upper conveyance path 15, and is then conveyed to the double-sided path 16 by switchback conveyance. Then, the sheet is turned upside down, temporarily stopped by the registration roller 23 again, the skew is corrected, and the sheet is re-fed at a predetermined timing. This time, the toner image is transferred to the back side by the transfer device 8. Thereafter, the sheet is discharged onto the sheet discharge storage section 3 through the fixing device 19 and the sheet discharge device 31.

Next, the optical scanning device 7 will be described. The optical scanning device 7 has two laser diode units 13 and 14 for exposing the two photoconductors 51 and 61 as shown in FIG. Each of the laser diode units 13 and 14 is provided with two laser diodes in order to cope with an increase in speed, and the laser diodes are arranged at a height shifted by one beam in the vertical direction. Two lines can be written. The laser light emitted from the laser diode of the laser diode unit 14 passes through the collimating lens and the aperture in the laser diode unit 14, passes under the return mirror 32, directly enters the polygon mirror 25, and rotates The mirror is reflected on one of the mirror surfaces provided on the polygon mirror 25 to perform one main scan. The laser beam reflected by the polygon mirror 25 is corrected by the fθ lens 26 so that the dot positional relationship is equal, and thereafter, as shown in FIG.
The light passes through the mirror 27 and is reflected by the mirror 27, enters the photoreceptor 61, and exposes the surface thereof.

On the other hand, the laser light emitted from the laser diode of the laser diode unit 13 shown in FIG. 3 passes through a collimating lens and an aperture in the laser diode unit 13 and is reflected by the turning mirror 32 to be reflected by the polygon mirror 25. The light enters one of the mirror surfaces, is reflected by one surface of the rotating polygon mirror 25, and performs one main scan. The laser light reflected by the polygon mirror 25 is corrected by the fθ lens 26 so that the positional relationship of the dots is equal, and thereafter, as shown in FIG. The surface of the photoconductor 51 is exposed through the mirror 35. Polygon mirror 25 and five folding mirrors 27, 32, 33,
34, 35, fθ lens 26 and long lenses 22, 24
Are integrated with the exposure frame 30, which is one case each.

The laser diode units 13, 1
4 is also integrally fixed to the exposure frame 30 as shown in FIG. As described above, the entire optical scanning device 7 is downsized by reflecting light emitted from the laser diode unit 13 by the return mirror 32 and guiding the light to the polygon mirror 25. The optical scanning device 7 detects the writing start position and the end position of the laser beam,
The four upper and lower laser beams are folded back by the mirrors for synchronization detection 36 and 37, and are polarized by the synchronization detection lenses 38 and 39 for condensing the upper and lower laser beams at the same height, and the positions are detected by the synchronization detectors 45 and 46. It is configured to detect.

The two dust-proof glasses 9 included in the optical scanning device 7 shown in FIG. 1 are transparent glass having a parallel surface on both sides, for example, a plate thickness of 2 mm. As shown in the figure, they are fixed to the lids 17 covering the upper part of the optical scanning device 7 in a posture substantially parallel to the direction of gravity (vertical direction in the figure). Therefore, in the case where the optical scanning device 7 is disposed below the first image forming unit 5 and the second image forming unit 6 as in the image forming apparatus described with reference to FIG. When the floating toners coming out of the developing devices 53 and 54 of the image unit 5 and the developing devices 63 and 64 of the second image forming unit 6 fall down, the two dustproof units shown in FIG. Although the dust-proof glass 9 is easily attached to the glass 9, each of the dust-proof glass 9 is disposed in a posture in which both the left and right planes are substantially parallel to the direction of gravity, so that the toner falls on the glass surface in the standing state. However, since the toner slides down on the glass surface by its own weight, it does not accumulate on each dustproof glass 9. For this reason, it is possible to prevent exposure failure that occurs when light for exposure is applied to a portion where toner adheres and accumulates on the dust-proof glass 9 and the light is blocked.

FIG. 4 is a view similar to FIG. 1 showing an image forming section and an optical scanning device of an image forming apparatus in which a dustproof member of the optical scanning device is formed by a thin light-transmitting sheet. The portions corresponding to are denoted by the same reference numerals. The image forming apparatus according to this embodiment differs from the image forming apparatus described with reference to FIG. 2 only in that a thin light transmitting sheet 49 is used as a dustproof member of the optical scanning device 7 '. The sheet 49 must be a light-transmitting sheet that has a strong property against impact and can obtain a desired strength even if the thickness is reduced, such as a polyethylene terephthalate (PET) film, a PEN film, and a fluorine film. A resin film, a silicone film, or the like is suitable, and the thickness is, for example, 0.1 mm.

As described above, the sheet 49 having a very small thickness is used.
When used as a dustproof member, it is necessary to prevent it from being distorted in the mounted state. Therefore, in this embodiment, as shown in FIG. 5, the periphery of the sheet 49 is adhered to the inner holding member 56 made of a metal plate with a double-sided tape so as not to float, and the inner holding member 56 is sandwiched between the sheets 49. The outer holding member 5 made of metal with the
7, a round projection 56a formed at the end of the inner holding member 56 is fitted into the hole at the end of the sheet 49, and the projection 56a is formed at the end of the outer holding member 57. The inner holding member 56, the sheet 49, and the outer holding member 57 are integrated with each other by fitting into the projection 57a and caulking the projection 56a, and the inner holding member 56, the sheet 49, and the outer holding member 57 are integrated with each other as shown in FIG. Also, the inside holding member 56 is not shown) and is fixed to the lid 17 of the optical scanning device 7 'by, for example, screws.

Incidentally, in the case of the optical scanning device 7 of the image forming apparatus according to the embodiment described with reference to FIGS. 1 to 3, the dustproof member is designed to withstand a certain degree of impact.
For example, a dustproof glass 9 having a thickness of 2 mm was used. On the other hand, as described with reference to FIG. 3, in the configuration in which the light emitted from the laser diode units 13 and 14 is scanned by the rotating polygon mirror 25, the light reflected by the polygon mirror 25 is reflected in FIG. As shown in the figure, at the center of the dust-proof glass 9 in the scanning direction (horizontal direction in the figure) (the inclination angle of the dust-proof glass 9 with respect to the direction of gravity is ignored for the sake of simplicity). In the dustproof glass 9, it advances by 2 mm corresponding to the thickness t and refracts out of the dustproof glass 9.

However, at both ends in the longitudinal direction (light scanning direction) of the dust-proof glass 9, light passing through the dust-proof glass 9 is inclined, for example, by about θ = 45 degrees with respect to the plane 9a on the incident side of the dust-proof glass. The light passes through the above-mentioned central portion of the glass at a distance of 2 mm.
通過 2 times (2 times the route, approximately 1.4 times) (2 · √2 = 2.83 mm), and the light inside the dustproof glass 9 at the center and both ends Is 2.83-2 = 0.83 mm. Therefore, the image at both ends in the optical scanning direction is distorted by the difference in the passing distance. As described above, when dustproof glass having a certain thickness is used for the dustproof member, the images at both ends in the optical scanning direction are likely to be distorted.

However, in the embodiment described with reference to FIGS. 4 and 5, a thin light-transmitting sheet 49 is used for the dust-proof member in order to compensate for the above-mentioned drawback, so that light can pass through both ends. Even if the distance becomes twice as large as the center, the thickness of the sheet 49 is extremely thin, for example, 0.1 mm. Is the difference in the distance
Since the passing distance at the center is 0.1 mm and the passing distance at both ends is 0.1√2 = 0.14 mm, the distance is 0.14 mm.
−0.1 = 0.04 mm, so that distortion of the image at both ends in the optical scanning direction is almost invisible. Also,
If a fluororesin film or a silicone resin film is used as the sheet 49, they are excellent in non-adhesiveness, so that even if the floating toner falls on the sheet 49, the toner hardly adheres to the sheet 49. Therefore, the toner does not easily accumulate on the sheet 49.

FIG. 7 is a view similar to FIG. 4 showing an embodiment of an image forming apparatus provided with an optical scanning device provided with a toner guide member in the vicinity of a dustproof member, and portions corresponding to FIG. Are attached. The image forming apparatus according to this embodiment is provided by fixing a toner guide member 71 made of conductive metal to the lid 17 in the vicinity of the sheet 49 as a dust-proof member with respect to the optical scanning device described with reference to FIG.
The only difference is that the toner guiding member 71 is grounded.

In this image forming apparatus, each light that passes through the light-transmissive sheet 49 and exposes the photoconductors 51 and 61 passes at approximately 45 degrees with respect to the plane of the sheet 49 as shown in the figure. The optical scanning device 7 ″ is arranged with respect to the photoconductors 51 and 61 so as to have a positional relationship.
As is apparent from FIG. 7, the developing devices 53 and 54 are not located immediately above the sheet 49 on the writing unit 11 side but on the left side in FIG.
The seat 49 is located on the left side in FIG. In the developing devices 53, 54, 63, and 64, the toner is charged to about −400 V, and the latent images on the photoconductors 51 and 61 are developed with the toner.
Therefore, at the time of development, each of the developing devices 53, 54, 6
The floating toner leaking from 3, 64 is negatively charged.

On the other hand, as described above, in this embodiment, the toner guiding member 71 made of a conductive metal is provided near the sheet 49 and is grounded. Since the positive charge is strengthened and the electrons escape to the ground side, each of the developing devices 53, 5
An electric field is generated between the toner guiding member 71 and the toner guiding member 71. This is the same as the principle of lightning. In the case of lightning, an electric field is created by a rain cloud of minus hundreds of million volts and a positive ground surface, which causes lightning to fall to the ground surface. At this time,
If there is a lightning rod made of a metal rod or the like, an electric field is generated between the lightning rod and the rain cloud, so that lightning strikes the lightning rod. When this phenomenon is applied to the embodiment described with reference to FIG. 7, the rain cloud hits each of the developing devices 53, 54, 63, and 64, and the lightning rod hits the toner guiding member 71 made of conductive metal, and is negatively charged. Since the floating toner thus generated is guided to the toner guiding member 71 by electrostatic induction, the floating toner hardly adheres to the sheet 49.

The toner guiding member 71 has an upper end which is closer to the image forming unit than the sheet 49 by 10 mm or more, and which can guide the toner falling near the sheet 49 to the toner guiding member 71 by electrostatic induction. It is fixed to the lid 17 by screws or caulking at the position. With this configuration, even if a part of the floating toner that has jumped out of the developing devices 53, 54, 63, and 64 may fall near the sheet 49, the toner is guided by the toner guiding member by electrostatic induction. Because it is attracted to 71, sheet 49
Does not adhere to Therefore, the light transmissive sheet 49
It is possible to prevent exposure failure caused by the toner blocking light when the toner is deposited thereon.

FIG. 8 is similar to FIG. 7 showing an embodiment in which a holding member for holding a light-transmitting sheet, which is a dustproof member, is made of conductive metal and the holding member also serves as a toner guiding member. FIG. 9 is a block diagram showing the configuration, and portions corresponding to FIG. 7 are denoted by the same reference numerals. The image forming apparatus according to the present embodiment is similar to the optical scanning apparatus described with reference to FIG. Is provided, and both the inner holding member 56 (not shown in FIG. 8 and FIG. 5; see FIG. 5) serving as the holding member and the outer holding member 87 are made of conductive metal. And a toner guiding portion 87a functioning as a toner guiding member on the outer holding member 87 near the sheet 49 (the same position as the toner guiding member 71 in FIG. 7).
7 and is fixed to the lid 17, which is different from the optical scanning device described with reference to FIG.

In this image forming apparatus, as in the embodiment of FIG.
The light exposing 1,61 is approximately 4 with respect to the plane of the sheet.
The optical scanning device is arranged with respect to the photoconductors 51 and 61 so that the optical scanning device passes through at an angle of 5 degrees. Therefore, the developing devices 53 and 54 are located on the left side in the figure without being located directly above the sheet 49 on the writing unit 11 side, and the developing devices 63 and 64 are also located on the right of the sheet 49 on the writing unit 12 side. It is located on the left side in the figure without being located on the top. In addition, the toner guiding portion 87a of the outer holding member 87 functioning as a toner guiding member has a plurality of ridges 88 formed at the tip thereof along the longitudinal direction as shown in FIG. As a result, the electric field tends to gather at the peak portion 88 at the tip of the toner guiding portion 87a. According to this embodiment, since the outer holding member 87 also serves as the toner guiding member, the number of parts can be reduced by the amount that the dedicated toner guiding member need not be provided. Therefore, the device can be made inexpensive accordingly.

In the outer holding member 87, as shown in FIG. 8, the top of the portion pressing the sheet 49 is substantially the same height as the toner guiding portion 87a, and the top has conductivity. Because of the metal, there is a possibility that the floating toner may be attracted to the toner by electrostatic induction. However, in this image forming apparatus, the developing units 53 and 54 are connected to the writing unit 11 as described above.
The developing device 63, 64 is not located directly above the sheet 49 on the writing unit 12 side, but is located on the left side in FIG. Since the optical scanning device is disposed so as to be positioned with respect to the photoconductors 51 and 61, the floating toner scattered from the developing devices 53, 54, 63, and 64 is written on the writing unit 11 side and the writing unit 1.
The toner guiding portions 87 of the outer holding members 87 on the two sides, respectively.
attracted by a. Therefore, the floating toner hardly falls near the sheet 49. Further, in this embodiment, as described with reference to FIG. 9, since a large number of peaks 88 are formed continuously at the tip of the toner guide portion 87a of each outer holding member 87, an electric field is easily collected there. Therefore, floating toner is less likely to be guided to the top of the portion of the outer holding member 87 that presses the sheet 49.

[0028]

As described above, according to the present invention, the following effects can be obtained. According to the image forming apparatus of the first aspect, since the dust-proof member of the optical scanning device is arranged in a posture in which its plane is substantially parallel to the direction of gravity, even if floating toner coming out of the image forming unit falls on the dust-proof member, The toner does not accumulate on the plane of the dust-proof member that is substantially perpendicular to the direction of gravity. Therefore, since the light emitted from the optical scanning device is not blocked by the toner accumulated on the dustproof member, it is possible to prevent the occurrence of a blank image. According to the image forming apparatus of the present invention, since the image forming unit is provided with the two photoconductors and the developing units corresponding to the respective photoconductors, the optical scanning unit located below the developing unit is provided. Since the frequency of toner falling on the apparatus increases, the effect of implementing the present invention is greater.

According to the image forming apparatus of the third aspect, in the case of an optical scanning device having a configuration in which light irradiated from a normal light source is scanned by a polygon mirror, light reflected by the polygon mirror is centered in the scanning direction of the dustproof member. The part advances inside the dustproof member by the thickness and bends out of the dustproof member,
At both ends of the dustproof member, the light passes through the dustproof member at an incident angle inclined, for example, about 45 degrees with respect to the plane of the dustproof member. √2 times that of Therefore, the image at both ends is distorted by the difference in the passage distance. However, by using a thin light-transmitting sheet for the dustproof member, the difference in the light passage distance between the center and both ends is reduced. Can be reduced even if it becomes √2 times as much as the thickness of the dustproof member, so that distortion of the image at both ends in the scanning direction can be made almost invisible.

According to the image forming apparatus of the fourth aspect, the toner guiding member made of conductive metal is provided near the dustproof member, and the toner guiding member is grounded. As a result, the toner floating near the dustproof member is attracted to itself by electrostatic induction, so that the toner does not easily adhere to the dustproof member. Therefore, the dust-proof member is less likely to be stained with the toner. According to the image forming apparatus of the fifth aspect, since a large number of peaks are formed at the tip of the toner guide member along the optical scanning direction, the electric field is easily collected at the peak at the tip of the toner guide member. Because the charged toner is attracted to the mountain,
The floating toner can be made more difficult to adhere to the dustproof member. According to the image forming apparatus of the sixth aspect, a holding member for holding the dustproof member in contact with a portion other than the place where the light of the dustproof member is transmitted is provided, and the holding member is formed of a conductive metal. Forming a toner guiding portion functioning as a toner guiding member on the holding member at a position near the dustproof member, and light passing through the dustproof member and exposing the photoreceptor substantially to the plane of the dustproof member. Since the optical scanning device is arranged with respect to the photoconductor so as to pass through at 45 degrees, the number of components is reduced because the holding member also serves as a toner guiding member, and there is no need to provide a dedicated toner guiding member. be able to. Therefore, the cost can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an image forming unit and an optical scanning device included in a two-drum color image forming apparatus that is an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is an overall configuration diagram showing the configuration of the two-drum color image forming apparatus.

FIG. 3 is a plan view showing the configuration of the optical scanning device in FIG. 1 with a cover opened.

FIG. 4 is a configuration diagram similar to FIG. 1 showing an image forming unit and an optical scanning device of an image forming apparatus in which a dustproof member of the optical scanning device is formed of a thin light-transmitting sheet.

FIG. 5 is a perspective view for explaining a mounting structure of a light transmitting sheet of the optical scanning device.

FIG. 6 is a plan view for explaining how light passes through a dust-proof glass at a center portion and at both end portions.

FIG. 7 is a configuration diagram similar to FIG. 4 illustrating an embodiment of an image forming apparatus including an optical scanning device provided with a toner guide member near a dustproof member.

FIG. 8 shows an embodiment in which a holding member for holding a light-transmitting sheet, which is a dustproof member, is formed of conductive metal, and the holding member also serves as a toner guiding member.
FIG.

FIG. 9 is a perspective view for explaining a shape of a distal end portion of an outer holding member which is a holding member for holding the light transmitting sheet.

[Explanation of symbols]

 7, 7 ', 7 ": Optical scanning device 9: Dustproof glass (dustproof member) 49: Sheet (dustproof member) 51, 61: Photoconductor 53, 54, 63, 64: Developing device (developing unit) 56, held inside Member 71: Toner guiding member 87: Outside holding member 87a: Toner guiding portion 88: Mountain portion

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 JA03 JB08 JB11 JC01 JC05 JC06 ZA07 2H030 AA00 AA06 AB02 BB02 BB23 BB42 2H076 AB05 AB06 AB12 AB18 AB22 AB33 AB60 AB82 EA01 2H109 CA21

Claims (6)

[Claims] An image forming section having a photoreceptor and a developing section for developing a latent image formed on the surface of the photoreceptor with toner to form a visible image; In an image forming apparatus including an optical scanning device that irradiates light onto the surface of the photoconductor by irradiating light to the surface of the photoconductor through a dustproof member formed on a plane in which both surfaces transmitting light are parallel to each other, An image forming apparatus, wherein the plane is arranged so that the plane is substantially parallel to the direction of gravity. 2. The image forming apparatus according to claim 1, wherein the image forming unit is provided with two photoconductors and a developing unit corresponding to each of the photoconductors. 3. The image forming apparatus according to claim 1, wherein the dustproof member is formed of a thin light-transmitting sheet. 4. The image forming apparatus according to claim 1, wherein a toner guide member made of a conductive metal is provided near the dustproof member, and the toner guide member is grounded. An image forming apparatus comprising: 5. The image forming apparatus according to claim 4, wherein a plurality of peaks are formed at a tip of said toner guiding member along a light scanning direction. 6. The image forming apparatus according to claim 4, wherein a holding member for holding the dustproof member in contact with a portion of the dustproof member other than a place where light is transmitted is provided, and the holding member is electrically conductive. The holding member is formed with a toner guiding portion that functions as the toner guiding member at a position near the dustproof member, and light that passes through the dustproof member and exposes the photoconductor is formed by a metal. An image forming apparatus, wherein the optical scanning device is arranged with respect to the photosensitive member so as to have a positional relation of passing through the dust-proof member at approximately 45 degrees with respect to a plane of the dust-proof member.