JPH0331265B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper separation device for a copying machine, and more particularly to a structure for installing a separation claw that separates paper attached during transfer from the surface of a photoreceptor.

[Prior art]

2. Description of the Related Art Conventionally, some copying machines use optical semiconductors to copy graphic information onto plain paper.

This is conceptually shown in FIG. 1. As the photoreceptor drum 1, on which the optical semiconductor is deposited on its circumferential surface, rotates, the charging corotron 2 first uniformly charges the surface of the photoreceptor drum 1. After copying, the calligraphic information on the document 4 placed on the platen 3 is scanned by light irradiation from the light source 5, and the reflected light 6 at this time is transmitted to an optical system composed of reflecting mirrors 7a, 7b and a lens 8. The electrostatic latent image is made incident on the photoreceptor drum 1 through a system to form an electrostatic latent image corresponding to the written image of the original document 4 on the surface of the photoreceptor drum 1. Next, in this copying machine,
This electrostatic latent image is visualized by a developing device 9,
The toner image thus obtained is transferred by a transfer corotron 10 to a charged paper 11. Further, in this copying machine, the photoreceptor drum 1 after the transfer and the residual toner on the surface of the photoreceptor drum 1 are electrically neutralized by the static eliminating corotron 12, and then the peripheral toner of the photoreceptor drum 1 is neutralized. The residual toner on the photoreceptor drum 1 is removed by the cleaning device 13, and the surface of the photoreceptor drum 1 is illuminated by the static elimination lamp 14 to completely eliminate the static electricity, thereby making it possible to use the photoreceptor drum 1 repeatedly. , the surface of the photosensitive drum 1 is charged again by the charging corotron 2. Thereafter, the above operation is repeated. Note that 15 is a paper tray on which recording paper is stacked, 16 is a feed roller that feeds the recording paper from above the paper tray 15, and 17 is a user that fixes the toner image on the recording paper.

By the way, in such a copying machine, as shown in FIG. 2, there is a
Separation claw 2 for separating paper 11 firmly adhered to the surface of photoreceptor drum 1 due to electrostatic force during transfer.
Some have 0.

This separating claw 20 has a tip end that is connected to the photosensitive drum 1.
The paper 11 that has been transferred is in sliding contact with the surface of the arrow A.
When the paper 11 adheres to the photoreceptor drum 1 rotating in the direction and moves, the leading edge of the paper 11 comes into contact with the separating claw 20, and as the paper 11 moves further, there is a gap between the photoreceptor drum 1 and the paper 11. Separation claw 20 intervenes and separates paper 11 from drum 1.

At this time, the separating claw 20 is attached to a shaft provided outside the tangent line 30 drawn to the sliding contact point 25 of the photosensitive drum 1 so that the separating claw 20 always comes into contact with the paper 11 attached to the photosensitive drum 1 and completes the separation work. It is mounted so as to be rotatable around a, and is always in sliding contact with the drum 1 due to the rotation moment generated by its own weight w acting on the center of gravity x.

However, with such a mounting structure, the axis a
is provided on the outside of the tangent line 30, so that the shaft a absorbs the frictional force generated between the drum 1 during sliding contact, the impact when it comes into contact with the paper, the pressure generated when separating the paper, etc. In response, the rotational moment applied to the separation claw 20 is generated so as to press the drum 1 (in the direction of arrow B), accelerating wear of the photoreceptor drum 1.

This has caused problems such as producing defective images and shortening the life of the photosensitive drum 1.

[Purpose of the invention]

The present invention focuses on such problems and provides a separating claw that reduces the rate of wear of the drum due to the paper separating claw and extends the life of the photosensitive drum so that high-quality copies can be made over a long period of time. With the goal.

[Structure of the invention]

Therefore, in the present invention, a fulcrum supporting the separating claw is provided inside a tangent line drawn to the sliding contact point of the drum, so that only the weight of the separating claw is applied to the drum sliding contact point, thereby achieving the above object.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, the separating claw 20a is formed in a dogleg shape, and the tip of one side thereof slides on the photosensitive drum 1, comes into contact with the paper 11, and separates the paper 11 from the drum 1.

The tip of the other side protrudes inside the tangent line 30 of the drum 1 drawn to the sliding contact point 25a, and a shaft b is provided in a part thereof. At this time, the shaft b is provided closer to the drum than the center of gravity x of the separation claw 20a, and the separation claw 20a
A is rotatably supported.

With this structure, the separating claw 20a is supported by the rotational moment generated only by its own weight, and always slides into contact with the drum 1 to complete the paper separation. Forces such as the impact force that contacts 20a, the frictional force caused by sliding contact, or the pressure of the paper 11 during separation occur on the tangent line 30, so these forces are supported by the axis b located inside the tangent line. When the separation claw 20a
The rotational moment applied to the drum 1 is directed outward in the radial direction of the drum 1 (in the direction of arrow C), and no unnecessary pressing force is applied to the drum 1.

The separating claw 20a can be made of plastic, for example. In this case, a cylindrical weight made of stainless steel is embedded approximately at the center of gravity x, and by adjusting this, an optimum sliding contact pressure can be maintained. Can be done.

Furthermore, when the circumferential speed of the photosensitive drum 1 is 200 mm/sec, if the distance y between the axis b and the tangent line is 7 mm, the angle θ on the drum 1 with respect to the vertical direction of the sliding contact point 25a
can be set to 30°.

〔Effect of the invention〕

As explained above, in the present invention, by providing the support shaft of the separation claw that separates the paper by slidingly contacting the photoreceptor drum inside the tangent line drawn to the sliding contact point of the drum, unnecessary pressing force is applied to the drum. It is possible to prevent the drum from being worn out, extend its lifespan, and provide high-quality images over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic illustration of a conventional copying machine, FIG. 2 is a schematic diagram of its separation claw, and FIG. 3 is a schematic diagram showing an embodiment of the separation claw according to the present invention. 1...Photosensitive drum, 11...Paper, 20,2
0a... Separation claw, 25, 25a... Sliding contact, 30
...Tangential line, a, b...Mounting axis.

Claims (1)

[Claims] 1. A separating claw is rotatably supported on the copying machine frame side by a shaft, and the tip of the claw is brought into sliding contact with the photosensitive drum to separate the plain paper stuck on the drum from the drum. A paper peeling device for a copying machine, characterized in that the shaft is located inside a tangent line drawn to a sliding contact point of a pawl on the drum.