JP2912995B2 - Image forming device - Google Patents

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 provided with a corona discharge device so as to face a photoreceptor surface.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system, the surface of a photoreceptor is uniformly charged by a corona discharger, and then a latent image is formed by an exposure system.

The corona discharger is provided so as to face the photosensitive member with a predetermined gap when the machine is assembled. However, in practice, the gap between the corona discharger and the photoconductor may vary due to the variation in dimensional accuracy of each unit of the machine. Therefore, conventionally, various techniques for adjusting the gap amount between the two have been proposed.

For example, a technique has been proposed in which the corona wire of the corona discharger or the main body of the corona discharger is movable so that the gap between the corona discharger and the surface of the photoreceptor can be adjusted. (Japanese Patent Laid-Open No. 56-1
No. 13158, No. 56-5952).

[0005]

However, in the above-mentioned prior art in which the corona wire of the corona discharger is moved and adjusted, the relative position of the corona wire with respect to the shield case changes with the adjustment operation.
This may cause uneven discharge.

Further, since the gap between the corona discharger and the photosensitive member is very small, when the corona discharger itself is moved to adjust the gap amount, the corona discharger comes into contact with the photosensitive member to expose the photosensitive member. There was a risk of damaging the body surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide a corona discharger in which a gap between a photoconductor and a corona discharger due to a variation in mechanical accuracy is allowed, and in particular, a corona discharger is permitted to move up to a range where the corona discharger contacts the photoreceptor. An object of the present invention is to provide an image forming apparatus capable of adjusting without making contact with a photoconductor.

[0008]

In order to achieve the above object, the present invention provides a corona discharge device installed to face a surface of a photoreceptor, and permits movement of the corona discharge device within a predetermined range. In an image forming apparatus having a movement permitting means and fixing means capable of fixing a corona discharger moved within a range permitted by the movement permitting means at a plurality of positions, the movement permitting means is such that the corona discharger is photosensitive. are those to the extent that contact with the body to permit movement of the corona discharger, further, the corona discharger than the distance co <br/> corona discharger and the photosensitive member in a direction perpendicular to the surface of the photosensitive member It is characterized by comprising positioning means for setting the distance short.

[0009]

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

FIG. 5 is a block diagram of an image forming apparatus according to the present invention. A document placed on a contact glass 1 is illuminated by light sources 2a and 2b, and the document image is reflected by a mirror 4
Exposure and projection are performed on the surface of the belt-shaped photoconductor 6 through the lens 3 and the mirror 5. The belt-shaped photoreceptor 6 includes a driving roller 18, a driven roller 19, and deviation adjusting rollers 20 and 21.
Supported by a corona discharger 22
After being uniformly charged to a constant potential, the original image is exposed, and an electrostatic latent image corresponding to the original image is formed. This electrostatic latent image is developed by toner supplied from the developing device 7 and visualized, and the toner image obtained by this is fed to the feed rollers 11a, 11b,
The transfer is performed by the transfer charger 13 on the transfer paper fed at a fixed timing through the registration roller 12 by 11c. After the transfer, the recording paper peeled off from the belt-shaped photoreceptor 6 by the separation charger 14 is discharged onto the paper discharge tray 10 via the conveyance device 28 and the fixing device 9. On the other hand, at the same time as the transfer is performed, the belt-shaped photoconductor 6
7 removes the charge, and removes the toner remaining on the surface after the transfer by the cleaning device 8. The belt-shaped photoconductor 6 is provided with a corona discharger 22.
Is charged again. In addition, the transmission type optical sensor 24 and the backup roller 1
5a, 15b and a light guide 25 are provided.

FIG. 2 is a perspective view showing a state in which the photoconductor unit is pulled out. The driving roller 18, the driven roller 19, and the deviation adjusting roller 2 for supporting the belt-shaped photoconductor 6 are shown.
Reference numerals 0 and 21 denote back side photoconductor side plate 30 and front side photoconductor side plate 3.
1 to form a photoreceptor unit. The photoconductor unit is slidably mounted by a pair of guide rails 32 provided in the apparatus main body so as to extend in the belt width direction.
The photoconductor unit is configured to be pulled out to the near side from the opening of the front plate 33 of the apparatus main body. When the photoreceptor unit including the belt-shaped photoreceptor 6 is pushed into the apparatus main body, the front side photoreceptor side plate 31 and the front side plate 33 of the apparatus main body are fixed by a fixing face plate 34, whereby the photoreceptor unit is Is immobilized. On the other hand, the corona discharger 22 is slidably mounted by a guide rail 35 which extends into the apparatus main body in a state parallel to the guide rail 32, and is also slidable from the opening of the front side plate 33 of the apparatus main body. It can be pulled out to the side.

FIG. 1 is a perspective view showing a mounting structure of a corona discharger which is a main part of the present invention, and FIGS. 3 and 4 are perspective views of a front side and a back side of the corona discharger. The case includes a long box-shaped main body 22a. A back support portion 22b and a front support portion 22c are provided at a rear end portion (left end portion in FIG. 3) and a front end portion (right end portion in FIG. 3) of the box-shaped main body 22a, respectively. A guide plate 22d fitted to the guide rail 35 on the apparatus main body side is attached to the box-shaped main body 22a. In particular, as shown in FIG. 1, a leaf spring 36 is provided on the guide rail 35, and the corona discharger 22 receives an urging force for pushing the corona discharger 22 upward by the leaf spring 36. . Further, a plurality of charge wires 22e are stretched inside the box-shaped main body 22a. 6 in parallel with the surface. A coil spring 22f constituting a power supply unit is provided so as to protrude from an end surface of the back side support portion 22b.

Further, pedestals 22g, 22g are formed on both side surfaces of the back side support portion 22b in the shield case so as to project to both sides.
g, 22g, the back side reference pins 22h, 22h are respectively fixed so as to protrude toward the back side.
When the whole of the corona discharger 22 is inserted into the apparatus main body, the rear side support portion 22b of the shield case collides with the belt-shaped photoreceptor 6 and the front side plate 33 of the apparatus main body. In order to prevent this, it is arranged at a portion between the guide plate 22d and the belt-shaped photoconductor 6.

On the other hand, reference holes 43, 43 are provided on the upper surface side of the near-side support portion 22c in the shield case. The rear-side reference pins 22h and 22h and the front-side reference holes 43 and 43 are provided in a state where the positional relationship is maintained with a predetermined accuracy so as to make a predetermined distance from the charge wire 22e.

The back side photoreceptor side plate 30 supporting the belt-shaped photoreceptor 6 of the photoreceptor unit is provided with the back side reference pin 2
The inner reference holes 30a, 30
0a is formed on the front side photoreceptor side plate 31, and reference pins 42, which are fitted with the front side reference holes 43, 43, respectively.
An adjustment plate 37 having 42 is attached. The adjusting plate 37 is provided for adjusting the distance between the front support portion 22c of the corona discharger 22 and the photoconductor 6 to a predetermined distance.

The adjusting plate 37 is provided with reference pins 40, 40, which are fitted into elongated holes 39, 39 provided on the front side plate 33 and extending in a direction perpendicular to the surface of the photoreceptor. The adjusting plate 37 can be moved in a direction perpendicular to the photoconductor 6 by loosely fitting the screw portion of the set screw 45 to 44. Therefore, the configuration movement permission means by the front Kichoana 44 the reference pin 40, and with the long hole 44 and the set screw 45, the fixing means by the set screw 45 is configured. Further, the adjustment plate 37 is stopped by the front side plate 33, and the distance from the photoconductor 6 is determined by the amount of eccentricity of the eccentric cam 38 fitted in the elongated hole 41. The reference pins 42 of the adjustment plate 37 and the near-side support portion 22 of the shield case
Since the reference holes 43 of c are fitted, the distance between the corona discharger 22 and the photoconductor 6 is adjusted by the adjusting method of the adjusting plate 37.

The fixing face plate 34 is shown in FIGS.
As shown in the figure, the front side support portion 22c of the shield case of the corona discharger 22 extends to face the photoconductor 6 side. In addition, the front side support portion 22 of the fixing face plate 34
The distance between the opposing portion c and the near-side support portion 22c is shorter than the distance between the corona discharger 22 and the photosensitive member 6.

In FIG. 1 and FIG. 2, the fixing face plate 34 protrudes from the photoconductor 6 to a position closer to the corona discharger 22, but naturally faces the fixing face plate 34 of the near-side support portion 22c. Protrusions are provided on the parts, and the corona discharger 22
The distance between the near-side support portion 22c and the fixing face plate 34 may be shorter than the distance between the photoconductor 6 and the front side support portion 22c.

As described above, when the distance between the corona discharger 22 and the photosensitive member 6 is adjusted by adjusting the adjusting plate 37, even if the corona discharger 22 is too close to the photosensitive member 6 by mistake, the near side support portion 22c Therefore, the corona discharger 22 does not hit the photoreceptor 6.

Thus, the corona discharger 2 can be easily and safely provided.
2 and the photoconductor 6 can be adjusted.

[0021]

As described above, according to the present invention,
As described above, when adjusting the gap between the corona discharger and the photoconductor, the corona discharger may
Contact from a direction perpendicular to the surface can be prevented.

[Brief description of the drawings]

FIG. 1 is a mounting structure diagram of a corona discharger which is a main part of the present invention.

FIG. 2 is a perspective view of a state where a photoconductor unit is pulled out.

FIG. 3 is a perspective view of the front side of the corona discharger.

FIG. 4 is a perspective view of the back side of the corona discharger.

FIG. 5 is a configuration diagram of an image forming apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 6 photoconductor 22 corona discharger 22c front side support portion 34 fixing face plate 37 adjusting plate 39 long hole 40 reference pin 42 reference pin 43 reference hole 44 long hole 45 set screw

Claims (1)

(57) [Claims] 1. A corona discharger installed to face a surface of a photoreceptor, a movement permitting means for permitting movement of the corona discharger within a predetermined range, and a movement permitting means provided within a range permitted by the movement permitting means. Fixing means for fixing the corona discharger moved at a plurality of positions in the image forming apparatus, wherein the movement permitting means permits movement of the corona discharger to a range where the corona discharger comes into contact with the photoreceptor. And
The image forming apparatus further includes a positioning unit that sets a distance between the corona discharger and the photoconductor shorter than a distance between the corona discharger and the photoconductor in a direction perpendicular to the surface of the photoconductor .