JP2774684B2 - Recording paper peeling device in image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus for forming an image by transferring a toner image formed on a peripheral surface of a photosensitive drum onto recording paper by a transfer device. The present invention relates to a recording paper peeling device used for peeling a recording paper on which a toner image has been transferred from a photosensitive drum.

(Prior Art) In an image forming apparatus such as an electrophotographic copying machine or a laser printer, an electrostatic latent image formed on a photosensitive drum is usually developed with toner, and the toner image is transferred to recording paper. Thus, an image is formed. Since the recording paper to which the toner image has been transferred is in contact with the photosensitive drum, a recording paper peeling device is used to peel the recording paper from the photosensitive drum.

The recording paper peeling device usually has a plurality of peeling claws juxtaposed at appropriate intervals along the photosensitive drum.
Each peeling claw is swingable so as to come into contact with and separate from the peripheral surface of the photoreceptor drum. The recording paper adhered to and conveyed to the peripheral surface of the photosensitive drum is peeled from the photosensitive drum.

(Problem to be Solved by the Invention) The swing of each peeling claw is usually performed by a driving means such as a solenoid arranged in the swing direction. In order to swing each peeling claw, the solenoid must be moved along the swing range of each peeling claw, and a large space is required to arrange driving means such as a solenoid. Further, for example, in an image forming apparatus in which a photosensitive drum, a developing device and the like are integrated as a process cartridge and which is detachably mounted on the apparatus main body, the entire recording paper peeling device is attached to the process cartridge. The driving means such as the oscillating solenoid is replaced together with the process cartridge, which is not economical.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a recording paper peeling apparatus which is miniaturized as a whole, and which can reliably swing a peeling claw, and which is more economical. Is to provide.

(Means for Solving the Problems) A recording paper peeling apparatus according to the present invention is an image forming apparatus that forms an image by transferring a toner image formed on a peripheral surface of a photosensitive drum onto recording paper by a transfer device. A recording paper peeling device used to peel off a recording paper onto which a toner image has been transferred from a photoconductor drum, and extends so as to be substantially perpendicular to the axial direction of the photoconductor drum; A peeling claw disposed so as to be swingable in a direction of coming into contact with and separating from the peripheral surface of the photosensitive drum; and a peeling claw disposed in a swinging range of the peeling claw so as to be movable in an axial direction along the photosensitive drum. A drive shaft made of a magnetic material whose peripheral surface is displaced along the axial direction in the swinging direction of the peeling claw, and urges the peeling claw to be pressed against a displaced portion of the peripheral surface of the drive shaft. Biasing means and pressure of the peeling claw along a displaced portion of the drive shaft. An electromagnet that moves the drive shaft by magnetic force in the axial direction so that the contact position is changed, wherein the electromagnet is disposed in the image forming apparatus main body, and the process cartridge is detachably attached to the image forming apparatus main body. The drive shaft is provided, thereby achieving the above object.

(Operation) In the recording paper peeling apparatus of the present invention, the drive shaft made of a magnetic material is moved in the axial direction by the magnetic force of the electromagnet while the peel claw is pressed against the drive shaft, so that the peel claw and the drive shaft are pressed. The position is changed so that the tip of the peeling claw is moved toward and away from the peripheral surface of the photosensitive drum. As a result, the recording paper conveyed while being attached to the peripheral surface of the photosensitive drum is peeled off from the peripheral surface of the photosensitive drum by the peeling claw that comes into contact with and separates from the peripheral surface of the photosensitive drum.

(Example) Hereinafter, an example of the present invention will be described.

As shown in FIG. 3, a copying machine, which is an image forming apparatus having the recording paper peeling device of the present invention, has a photosensitive drum 10 disposed substantially at the center of the body. The photosensitive drum 10
Is rotated in the direction indicated by arrow A in FIG. A charging device 11 is provided above the photosensitive drum 10, and the charging device 11 charges the peripheral surface of the photosensitive drum 10 to, for example, minus. A developing device 12 is provided downstream of the charging device 11 in the rotation direction of the photosensitive drum 10. The peripheral surface of the photoconductor drum 10 charged by the charging device 11 is exposed to light 17 for image formation passing between the charging device 11 and the developing device 12, and the peripheral surface of the photoconductor drum 10 is exposed. An electrostatic latent image is formed on the surface. Then, the positively charged toner adheres to the electrostatic latent image formed on the peripheral surface of the photosensitive drum 10 by the developing mag roller 12a in the developing device 12, and a toner image is formed on the photosensitive drum 10. You.

A transfer device 13 is provided below the photoconductor drum 10, and the transfer device 13 transfers a toner image on the photoconductor drum 10 onto a recording paper 18 conveyed below the developing device 12. Is transferred.

On the side of the transfer device 13 in the recording paper conveyance direction, a static elimination plate
15 are arranged vertically. The charge removing plate 15 removes static electricity on the recording paper adhered to the photosensitive drum 10 and conveyed.

A cleaning device 14 is provided beside the photosensitive drum 10 in the transfer device 13 on the downstream side in the rotation direction of the photosensitive drum 10.
A recording paper peeling device 20 for peeling the recording paper, onto which the toner image has been transferred, from the photosensitive drum 10 is disposed below the cleaning device 14. A transport device 16 for transporting the recording paper peeled from the photosensitive drum 10 is provided below the recording paper peeling device 20, and the transport paper 16 transports the recording paper to a fixing device (not shown). Is done. The peripheral surface of the photoreceptor drum 10 from which the recording paper has been removed is cleaned by the cleaning device 14, and the toner remaining on the peripheral surface is stored in the waste toner container 14a in the cleaning device 14.

In this embodiment, the photosensitive drum 10, the developing device 12, and the cleaning device 14 are integrated as a process cartridge, and are detachable from the machine.
The process cartridge is, for example, a cleaning device
It is replaced when the waste toner container 14a in 14 becomes full.

As shown in FIGS. 1 and 2, the recording paper peeling device 20 of the present invention includes a plurality of peeling claws 21 arranged at appropriate intervals in the axial direction of the photosensitive drum 10, and each of the peeling claws 21. And one drive shaft 24 which is pressed against the upper surface of 21 to swing each peeling claw 21.

Each of the peeling claws 21 extends in a direction orthogonal to the axial direction of the photoconductor drum 10, and the tip on the photoconductor drum 10 side is sharpened. Each peeling claw 21 is supported by a support shaft 22 on the lower surface of the cleaning device 14 at a position near the base end far from the photosensitive drum 10 by a support shaft 22 so as to be vertically swingable. . The base end of each peeling claw 21 is
, And the tip of each peeling claw 21 is urged upward. The pressing spring 23 is located in a concave portion formed on the lower surface of the cleaning device 14.

The drive shaft 24 of each peeling claw 21 is disposed in the swinging range of the peeling claw 21 below the cleaning device 14 so as to be substantially parallel to the axial direction of the photosensitive drum 10. The drive shaft 24
Is supported on the lower surface of the cleaning device 14 so as to be movable in the axial direction. The peripheral surface of the drive shaft 24 is
The upper surface of each peeling claw 21 is positioned so as to be in contact with the upper surface of the portion closer to the distal end side than the support shaft 22 of 21. It is pressed against the peripheral surface of the drive shaft 24.

The drive shaft 24 is made of, for example, a magnetic material, and an electromagnet 25 is arranged to face one end of the drive shaft 24. The electromagnet 25 is attached to, for example, a copying machine main body on which a process cartridge is mounted. A compression spring 26 is fitted to an end of the drive shaft 24 close to the electromagnet 25. One end of the compression spring is in contact with a spring seat 24a provided at an appropriate distance from the end face of the drive shaft 24 facing the electromagnet 25, and the other end is The spring 26 is in contact with a spring seat 14b provided on the lower surface of the cleaning device 14 so as to urge the entire drive shaft 24 away from the solenoid 25.

The drive shaft 24 is attracted to the electromagnet 25 by being energized by the electromagnet 25, against the urging force of the compression spring 26,
When the energization to the electromagnet 25 is stopped, the electromagnet 25 is moved away from the electromagnet 25 by the compression spring 26.

When the drive shaft 24 is moved in the axial direction, a tapered surface 24b is provided on the peripheral surface on which each peeling claw 21 is pressed against in order to gradually reduce the diameter along the direction in which the drive shaft 24 is moved by the spring force of the compression spring 26. The tapered surface 24b is provided with a constant small diameter portion 24c. Therefore,
The peripheral surface of the drive shaft 24 is displaced in the swing direction of each peeling claw 21 along the axial direction.

Each peeling claw 21 is normally in contact with the large-diameter peripheral portion of the drive shaft 25 near each tapered surface 24b by the downward biasing force of the pressing spring 23. The drive shaft 24 is compressed by an electromagnet 25
When being pulled against the pressing force of 26, the upper surface of each peeling claw 21 comes into sliding contact with each tapered surface 24b and then comes into sliding contact with the small diameter portion 24c. Therefore, the distal end of each peeling claw 21 is sequentially moved upward by the pressing force of the pressing spring 23 and comes into contact with the peripheral surface of the photosensitive drum 10.

The operation of the peeling device 20 having such a configuration is as follows. By the image forming operation of the copying machine, a toner image is formed on the peripheral surface of the photosensitive drum 10 and the toner image is transferred to the recording paper conveyed by the transfer device 13. At the beginning of such an image forming operation, the electromagnet 25 is not energized, and the drive shaft 24 is moved by the compression spring 26 in the direction indicated by the arrow B in FIG. As a result, each peeling nail
The upper surface of 21 is in contact with the large-diameter peripheral surface of the drive shaft 24, and the tip of each peeling claw 21 is away from the peripheral surface of the photosensitive drum 10.

When the toner image is transferred onto the recording paper by the transfer device 13, the recording paper is conveyed together with the photosensitive drum 10 in a state of being attached to the peripheral surface of the photosensitive drum 10. At this time,
A drive shaft energized by the electromagnet 25 and made of a magnetic material
24 is attracted to the electromagnet 25 and is moved in the direction opposite to the direction indicated by the arrow B in FIG. As a result, after the upper surface of each peeling claw 21 whose base end is urged downward by the pressing spring 23 slides from the large-diameter peripheral surface portion of the drive shaft 24 to each tapered surface 24b, each small-diameter portion 24c Contact each other. Accordingly, the tips of the peeling claws 21 sequentially move upward and come into contact with the peripheral surface of the photosensitive drum 10.

In this state, when the recording paper adheres to the peripheral surface of the photosensitive drum 10 and is conveyed, the leading end of the recording paper in the conveying direction is guided to the lower surface of each peeling claw 21, and the photosensitive drum 10 is sequentially moved. Peeled off from Thereafter, the energization of the electromagnet 25 is stopped, and the drive shaft 25 is moved by the compression spring 26 in a direction away from the electromagnet 25. Thereby, the upper surface of each peeling claw 21 is
The small-diameter portion 24c contacts the large-diameter peripheral surface portion via the tapered surface 24b, and the tip of each peeling claw 21 is sequentially moved downward away from the photosensitive drum 10.

As described above, by moving the drive shaft 24 in the axial direction, each peeling claw 21 can be brought into contact with or separated from the photosensitive drum 10, so that the whole peeling device can be significantly reduced in size. Even if the movement of the drive shaft 24 is slight, each peeling claw 21 is reliably swung. When the drive shaft 24 is moved by the electromagnet 25 using the drive shaft 24 as a magnetic material as in the above-described embodiment, there is no need to connect the drive shaft 24 and the electromagnet 25. With the arrangement, the drive shaft 24 and the like can be attached to the process cartridge. Drive shaft 24
Is made of a magnetic material, the drive shaft can be used as a plunger of a solenoid.

The peeling claw 21 is tapered from the large diameter peripheral surface of the drive shaft 24.
After being pressed against 24b, to be pressed against the small diameter part 24c,
The tip of the peeling claw 21 is gradually brought into contact with the peripheral surface of the photosensitive drum 10. Therefore, there is no possibility that the peripheral surface of the photosensitive drum is damaged by the peeling claw 21.

(Effect of the Invention) The recording paper peeling device of the present invention has a configuration in which the peeling claw is operated by moving the drive shaft of the magnetic body in the axial direction by the magnetic force of the electromagnet, and the configuration of the peeling device is simple. It can be downsized.

In addition, since the drive shaft and the electromagnet are not directly connected, when replacing the process cartridge, the operation of releasing the connection is not required, and the replacement operation is facilitated.

Furthermore, since the drive shaft and the electromagnet are not directly connected, a mechanism for releasing the connection is not required.In addition, the electromagnet is arranged in the apparatus main body, and the electromagnet is driven to a process cartridge which is detachably attached to the apparatus main body. Since the shaft is provided, only the drive shaft is replaced when the process cartridge is replaced, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of an essential part showing an example of a recording paper peeling device according to the present invention, FIG. 2 is a sectional view thereof, and FIG. 10 photoreceptor drum, 14 transfer device, 20 peeling device, 21 peeling claw, 22 support shaft, 23 pressing spring, 24
…… Drive shaft, 24b …… Tapered surface, 24c …… Small diameter part, 25…
…electromagnet.

────────────────────────────────────────────────── (5) References JP-A-58-200274 (JP, A) JP-A-60-239785 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/14

Claims (1)

(57) [Claims] An image forming apparatus for forming an image by transferring a toner image formed on a peripheral surface of a photosensitive drum onto a recording sheet by a transfer device, wherein the recording sheet on which the toner image has been transferred is contacted with the photosensitive drum. A recording paper peeling device used for peeling off from the photosensitive drum, extending substantially perpendicularly to the axial direction of the photosensitive drum, and swinging in a direction in which a tip portion comes into contact with or separates from a peripheral surface of the photosensitive drum. A peeling claw movably disposed; and an oscillating movement of the peeling claw along an axial direction along the photosensitive drum within a swing range of the peeling claw. A drive shaft made of a magnetic material having a circumferential surface displaced in a direction, a biasing unit for biasing the peeling claw to be pressed against a displacement portion on the circumferential surface of the drive shaft; The drive shaft in the axial direction so that the pressure contact position of the peeling claw varies An electromagnet that is moved by a magnetic force, wherein the electromagnet is disposed in the image forming apparatus main body, and the recording paper peeling device in the image forming apparatus is provided with the drive shaft in a process cartridge detachably attached to the image forming apparatus main body. .