JP2002268396A - Paper-peeling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper-peeling device by which uneven wear will not be caused on a photoreceptor drum. SOLUTION: This device is provided with a rotary cam 30 which is connected with several peeling claws 25, brought into press-contact with the photoreceptor drum and by which the peeling pawls 25 are moved in the width direction of the photoreceptor drum. The rotary cam 30 is set, so as to form a locus drawn by the individual claw 25 on the rotating photoreceptive drum into a triangular wavy form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper peeling device for peeling paper adhered to a photosensitive drum in an image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus which forms an electrostatic latent image on a photosensitive drum, applies toner to the electrostatic latent image, develops the electrostatic latent image, and transfers an image developed with the toner to a sheet of paper, is particularly known. JP-A-61-223770 and JP-A-Hei1-1
As shown in JP-A-42778, a paper peeling device for peeling paper adhered to a photosensitive drum is provided. FIGS. 10 to 13 show an example of this paper peeling device.
It will be described based on. First, a support shaft 2 is provided along the width direction of the photosensitive drum 1, and a peeling claw 3 is fixed to the support shaft 2 in the axial direction and rotatably attached thereto.
The peeling claw 3 is urged by a torsion string spring 4 passed through the support shaft 2 so as to rotate in a direction of pressing against the photosensitive drum 1. The support shaft 2 is
One end thereof is urged in the axial direction by a compression spring 5, and the other end is pressed against the cam surface of the cylindrical cam 6. The cylindrical cam 6 is connected to a drive unit (not shown) via a speed reducer 7, and the cam surface has a shape obtained by cutting a cylinder by a plane inclined with respect to the axis.

In such a configuration, when the cylindrical cam 6 is driven, the spindle 2 reciprocates in the axial direction by the action of the cylindrical cam 6, and the peeling claw 3 reciprocates in the width direction of the photosensitive drum 1. . In this way, the peeling claw 3 peels off the paper stuck on the photosensitive drum 1 while reciprocating on the photosensitive drum 1. The locus drawn by the peeling claw 3 on the photosensitive drum 1 is a sine wave as shown in FIG. FIG. 13 shows the contact probability density of the peeling claw 3 on the photosensitive drum 1 in this case.

[0004]

In the above-described paper peeling device, as is apparent from FIG. 13, the contact probability density of the peeling claw 3 on the photosensitive drum 1 is not constant, and especially the density at both ends of the reciprocation. Is extremely high as compared with the others, so that there is a disadvantage that uneven wear occurs on the photosensitive drum 1 and the life of the photosensitive drum 1 is shortened. Also,
Since the torsion string spring 4 is used to urge the peeling claw 3, there is a drawback that the assemblability is poor, and the torsion string spring 4 has a large variation in the urging force. It has the disadvantage that it can cause wear. Further, the above-described paper peeling device includes a support shaft 2
However, they have the disadvantage that space efficiency is poor because they take up a large space.

[0005]

According to the first aspect of the present invention, there is provided a moving mechanism which is connected to a plurality of peeling claws pressed against the photosensitive drum and moves the peeling claws in the width direction of the photosensitive drum. In the paper peeling apparatus, the moving mechanism is set such that the trajectory drawn by each of the peeling claws on the rotating photosensitive drum has a triangular waveform.

Therefore, by setting the moving mechanism so that the trajectory drawn by each peeling claw on the rotating photosensitive drum has a triangular waveform, the contact probability density of the peeling nail on the photosensitive drum becomes constant, and Uneven wear of the drum is prevented.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. First, an image forming apparatus in which the sheet peeling device of the present embodiment is incorporated will be described.
As shown in FIG. 2, the image forming apparatus includes a paper feed tray 8
A paper transport path 10 is formed to communicate with the paper discharge tray 9, and a photosensitive drum 12 is pressed against a transport belt 11 disposed along the paper transport path 10 to form a transfer unit 13. Have been. A fixing device 14 is provided downstream of the transfer unit 13. Here, the photosensitive drum 12 is separated from the transfer unit 13 in a rotational direction (right rotation in FIG. 2) by a paper peeling device 15 that peels off the paper adhered at the transfer unit 13, A cleaning device 16 for removing toner, a charge removing device 17 for removing charge from the photosensitive drum 12, a charging device 18 for charging the photosensitive drum 12, an exposure device 19 for forming an electrostatic latent image on the photosensitive drum 12, A developing device 20 for developing the electrostatic latent image with toner is provided in order.

That is, in this image forming apparatus, first, the photosensitive drum 12 is uniformly charged by the charging device 18 and the exposure device 1
At 9, an electrostatic latent image is formed on the photosensitive drum 12. Then, the electrostatic latent image is developed by the developing device 20 with toner, and the transfer unit 13 presses the photosensitive drum 12 against the sheet to transfer the toner on the photosensitive drum 12 to the sheet. Subsequently, the paper that has been adhered to the photosensitive drum 12 at the transfer unit 13 and that has not been peeled off is peeled off by the paper peeling device 15, the residual toner on the photosensitive drum 12 is removed by the cleaning device 16, and the electricity is removed by the charge removing device 17. Photoconductor drum 12
And the charging device 18 charges the photosensitive drum 12 again. An image is formed by continuously repeating this process. The toner transferred to the sheet by the transfer unit 13 is heated by the fixing device 14 and is fixed on the sheet.

Next, the sheet peeling device 15 which is a feature of the present embodiment will be described in detail. First, as shown in FIG. 3, the base panel 21 extends along the width direction of the photosensitive drum 12.
(Substrate) is disposed on the base panel 21 (FIG. 3).
The lower surface of the photosensitive drum 12
And is attached with a stepped pin 23 so as to be movable in the width direction of the motor. In addition, as shown in FIG.
1, a downwardly protruding mounting seat 21a is formed in the caulked portion of the stepped pin 23 by half-blanking, and the mounting seat 21a reduces friction with the slide panel 22.

Subsequently, two support shafts 24 are disposed at a predetermined interval along the width direction of the photosensitive drum 12, and peeling claws 25 are rotatably mounted on the respective support shafts 24. . The support shaft 24 is attached to a flange formed by bending the lower surface of the slide panel 22. Then, a compression spring 27 for rotating the peeling claw 25 in a direction in which the peeling claw 25 comes into pressure contact with the photosensitive drum 12 is provided.
As shown in the figure, the slide claw 25 is provided between the rear end of the release claw 25 and the slide panel 22. The compression spring 27 is provided with mounting bosses 25a, 22a projecting from the rear end of the peeling claw 25 and the slide panel 22 so as to face each other.
Is held by Further, at the position where the tip of the peeling claw 25 pressed against the photosensitive drum 12 is virtually cut into the photosensitive drum 12, it comes into contact with the slide panel 22 against the urging force of the compression spring 27. Rotation stop boss 28 for stopping rotation of the peeling claw 25
A (rotation stopping member) is protruded from the peeling claw 25. An image density detecting sensor 29 (image density detecting means) is provided between the peeling claws 25. This image density detection sensor 29 is for detecting the amount of toner on the photosensitive drum 12 and feeding it back.
As shown in FIG. 6, it is attached to a bracket 21b formed by bending the base panel 21.

Next, as shown in FIGS. 1 to 4, a rotary cam 30 (moving mechanism) having a cam groove 30a on the side surface is provided on the slide panel 22 via a cam follower 31 projecting from the slide panel 22. It is connected.
The rotary cam 30 is rotatably fixed to the base panel 21 and has a gear formed on the outer periphery. A small gear 32 and a worm formed integrally with the small gear 32 are formed in a drive unit (not shown). Wheel 33, worm gear 3
4. Reduction gear train 37 composed of drive shaft 35 and drive gear 36
Connected through. The reduction gear train 37 is all attached to the base panel 21. The worm wheel 33 is replaced by a helical gear, and the cost is greatly reduced. The cam groove 30a of the rotary cam 30 is represented by the following equation: r = a (θ / 90 ° -1) 2a = required cam stroke r = distance from rotation center to cam groove θ = rotation angle (deg) It is curved (FIG. 7).

In such a configuration, when the rotary cam 30 is rotated by being driven by a drive unit (not shown), the slide panel 22 reciprocates in the width direction of the photosensitive drum 12 by the action of the rotary cam 30, and the slide panel The peeling claw 25 mounted on the photosensitive drum 22 also reciprocates in the width direction of the photosensitive drum 12. Here, the locus drawn by the peeling claw 25 on the photosensitive drum 12 is a triangular wave as shown in FIG. FIG. 9 shows the contact probability density of the peeling claw 25 on the photosensitive drum 12 at this time. As is clear from the figure, the contact probability density is almost constant in the movable range of the peeling claw 25. For this reason, uneven wear of the photosensitive drum 12 can be prevented, and its life can be extended. Note that the reason why the density at both ends of the reciprocation is slightly higher than the other is that the inflection point of the cam is smoothly processed.

Further, in the present embodiment, since the urging of the peeling claw 25 is performed by the compression spring 27, assemblability can be improved as compared with the case where a torsion string spring is used, and the urging force is further improved. Therefore, uneven wear of the photosensitive drum 12 can be prevented, and the life of the photosensitive drum 12 can be extended. further,
At the position where the tip of the peeling claw 25 is virtually cut into the photosensitive drum 12, the peeling claw 2 is opposed to the urging force of the compression spring 27.
Since the rotation stop boss 28 for stopping the rotation of the photosensitive drum 12 is provided, the rotation of the peeling claw 25 is stopped by the rotation stop boss 28 when the photosensitive drum 12 is removed for replacement or the like. The detachment of the spring 27 can be prevented. In addition, peel nail 2
Since the support shafts 24 to which the 5 is attached are provided independently for each peeling claw 25, assemblability can be improved as compared with the case where all the peeling claws 25 are attached to one support shaft. Since the support shaft between the peeling claws 25 can be eliminated, the space efficiency can be improved. Further, since the sheet peeling device 15 of the present embodiment is integrally formed on the base panel 21, it can be handled as one unit, and assemblability can be improved.

[0014]

According to the first aspect of the present invention, there is provided a sheet having a moving mechanism which is connected to a plurality of peeling claws which are pressed against a photosensitive drum and moves the peeling claws in the width direction of the photosensitive drum. In the peeling device, by setting the moving mechanism so that the trajectory drawn by each of the peeling claws on the rotating photosensitive drum has a triangular waveform, the contact probability density of the peeling nail on the photosensitive drum becomes constant. Therefore, uneven wear of the photoconductor drum can be prevented, and the life of the photoconductor can be prolonged.

[Brief description of the drawings]

FIG. 1 is a top view of a paper peeling device according to an embodiment of the present invention, showing a base panel as a virtual line.

FIG. 2 is a longitudinal sectional side view showing a mechanism of the entire copying machine.

FIG. 3 is a perspective view showing a sheet peeling device.

FIG. 4 is a longitudinal sectional front view thereof.

FIG. 5 is a vertical sectional side view thereof.

FIG. 6 is a vertical sectional side view.

FIG. 7 is an explanatory diagram showing a cam shape.

FIG. 8 is a graph showing a locus drawn by a peeling claw on a photosensitive drum.

FIG. 9 is a graph showing a contact probability density of a peeling claw on a photosensitive drum.

FIG. 10 is a vertical sectional side view showing an example of the related art.

FIG. 11 is a top view thereof.

FIG. 12 is a graph showing a locus drawn by a peeling claw on a photosensitive drum.

FIG. 13 is a graph showing a contact probability density of a peeling claw on a photosensitive drum.

[Explanation of symbols]

 REFERENCE SIGNS LIST 12 photoreceptor drum 15 paper peeling device 21 substrate 24 support shaft 25 peeling claw 27 urging means 28 rotation stop member 29 image density detecting means 30 moving mechanism

Claims (1)

[Claims] 1. A paper peeling device comprising a moving mechanism connected to a plurality of peeling claws pressed against a photosensitive drum and moving the peeling claws in a width direction of the photosensitive drum. A paper peeling device wherein the moving mechanism is set such that a locus drawn by each of the peeling claws has a triangular waveform.