JPH0513317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a mechanical separation mechanism for transfer paper in an image forming apparatus, and more particularly to a bearing technology for a transfer paper separation claw support shaft provided on a photoreceptor drum.

Prior Art There are many opportunities for toner to scatter around the photoreceptor in a copying machine near a developing device or a cleaning device. For this reason, dustproof seals and devices have been researched and put into practice for some time, but they have not always been sufficiently effective.
As machines become faster, it is nearly impossible to completely prevent toner from scattering. On the other hand, high-speed devices are also required to have high reliability, and it is necessary to avoid adverse effects caused by toner scattering as much as possible.

By the way, conventionally, the separation claw of the transfer paper has been supported so as to be able to move toward and away from the photoreceptor drum so as not to damage the surface of the photoreceptor drum, and when the edge of the transfer paper moves near the tip of the separation claw, It is designed so that it only touches the drum surface and separates after passing that point, and it also allows reciprocating movement in the direction of the rotational axis of the drum, that is, in the direction of the generatrix of the drum surface, avoiding constant contact at a fixed position. It is provided in
The separation claw mechanism, which is used to ensure the effect of separating the transfer paper from the photoconductor, cannot be installed outside the toner scattering area, including the bearing of the support shaft. It was also necessary to clean the bearing part.

FIG. 1 shows a side view of the main part of the photoreceptor drum of a conventionally used copying machine. In the figure, 1 is the photoreceptor drum, which rotates in the direction of the arrow and undergoes processes such as charging and exposure. , forming an electrostatic latent image on the drum surface. When the drum surface on which the latent image exists moves to face the developing device, toner adheres to the electrostatic latent image as the mag roller 3 rotates, and a developed image is formed on the drum surface. Next, the developed image is charged facing the pre-transfer static elimination charger 4, while the transfer paper sent from the registration roller pair 5 remains in close contact with the drum 1 at position A on the drum surface.
As it moves along with the drum surface, it is charged from the back side by a transfer charger 6 and the developed image is transferred to the transfer paper side. Next, the transfer paper is charged by a separation charger 7, separated from the drum 1, and transported by a conveyor belt 8 to a fixing section.

However, depending on the environment and the type of transfer paper, some transfer paper may be difficult to separate from the drum 1. Such a transfer paper 2 is mechanically separated from the drum 1 by a separating claw 10.
Since it separates from the surface, the separation claw 10 has a function of a separation action ensuring mechanism.

The toner remaining on the surface of the drum 1 is scraped off by the cleaning section 11 at the next stage, and then undergoes a static elimination step to complete one cycle of the copying step.

Now, the separation claw 10 is made of a metal material having an edge at its tip, and is arranged in parallel with the support shaft 14. Therefore, if it is constantly in contact with the surface of the drum 1, the surface may be scratched, the photosensitive layer may peel off, and white or black lines may appear on the copied image. In order to prevent this, when the edge of the transfer paper passes the tip of the claw 10, the solenoid 12 is turned OFF and its plunger protrudes in the direction of the arrow, as shown in FIG. The lever 20 supported by the shaft 14 in a cantilever manner is released by swinging in the direction of the arrow, and the tip of the separating claw 10 connected to the lever 20 via a coil spring is operated to separate from the surface of the drum 1.

When bringing the tip of the separating claw 10 into contact with the surface of the drum 1, as shown in FIG. 2a, the solenoid 12 is activated.
Turn on and pull the plunger in the direction of the arrow.
When the intermediate lever is swung in the direction of the arrow and the lever 20 is pushed in the direction of the arrow, the end of the separation claw 10 interlocked with the coil spring can be swung so as to lightly contact the drum surface.

Furthermore, as shown in FIG. 3, the separation claw 10 is
Since the photosensitive drum 1 reciprocates in parallel to the rotation axis of the photosensitive drum 1, and is designed so that the contact surface of the claw 10 is not fixed at one specific location on the drum surface, its mechanism will be explained below. FIG. 3a is a plan view of the main parts of the separation claw support shaft and its bearing part, and FIG. 3b is a side view of the main parts as seen perpendicularly to the line bb. In the figure,
Reference numeral 18 denotes an eccentric cam that rotates in conjunction with the copying operation.
Reference numeral 19 denotes a swinging arm having one end in contact with the cam, and the other end in contact with a lever provided with a one-way clutch, which is rotated every revolution of the cam 18, as indicated by the arrow in Fig. 3b. It is rocked back and forth like this.

Its operation involves intermittently rotating the shaft of the cam 13 that engages the one-way clutch,
The intermittent rotation of the cam 13 causes the separation claw 10, one end of which is in contact with the surface thereof, to reciprocate in the axial direction of the support shaft 14.

Reference numeral 14 denotes a shaft supporting a plurality of separation claws 10, one end of which is lightly abutted against the surface of the cam 13 by a coil spring from the other end. Further, the central portion to which the separating claw 10 is fixed is connected to other portions of the shaft 14 via a joint so that it can be replaced. A swing lever 20 is attached to the other end of the support shaft 14 via a coil spring.
is fixed in a cantilevered manner, and this lever 20 swings the separating claw 10 by operating as explained in FIG. It is set in.

Reference numeral 15 denotes a bearing part that supports the coaxial shaft near both ends of the support shaft 14. When this part is shown in cross section, it is a plain bearing as schematically shown in Fig. 4, and in the same figure, 10 is a separation claw. , 14 is its support shaft, and the support shaft 14 is connected to the bearing 15 as mentioned earlier.
oscillates against and slides back and forth in the direction perpendicular to the figure.

Returning to FIG. 1 again, the toner scraped off by the cleaning section 11 leaks from the seal and adheres to the support shaft 14, or the toner on the transfer paper, the toner from the developing device, or the residual toner on the drum 1. Some of them scatter into the air and adhere to the separation claw support shaft 14. The support shaft 14 swings as described above,
Further, since the shaft 14 reciprocates in the axial direction, a portion of the toner attached to the surface of the shaft 14 near the bearing portion 15 enters the bearing surface. The conventional bearing part 15 is
With a plain bearing as shown above, the gap between the support shaft 14 and the bearing part is 0 to 0.1 mm,
Since the gap is at most 0.2 mm or less, if toner enters this gap, the resistance to the swinging and sliding of the shaft 14 will increase, and if it gets worse, the resistance will overcome and the supporting shaft 14 will swing and slide. If the separator 10 becomes unable to slide, white streaks or black streaks will appear on the transferred image, or if the separation claw 10 locks away from the surface of the drum 1, it may cause a jam.

Purpose Therefore, the device of the present invention cuts out an escape part for foreign matter that has entered the bearing surface of a shaft that swings or slides in an atmosphere where dust is scattered.
The purpose of this invention is to prevent defective shaft rocking and sliding caused by microscopic foreign matter attached to or floating on the shaft entering the bearing surface. In particular, it is an object of the present invention to provide a device that is effective for use in bearings that operate in environments where there is a lot of toner scattering, such as the support shaft of a separation claw located below the cleaning section of a photoreceptor in a copying machine.

Configuration The device of the present invention includes: a shaft that supports a plurality of separation claws; a bearing that supports the shaft; a means for moving the shaft in the axial direction of the photoreceptor; and a device that separates the separation claws in the direction of the photoreceptor. In the image processing device, a cutout groove extending in the generatrix direction is provided on the inner circumferential surface of the bearing portion, and the shaft-side end of the wall constituting the groove is located at a position where the end comes into contact with the shaft. An image forming apparatus characterized in that the image forming apparatus is formed substantially perpendicular to a tangent to the axis of the image forming apparatus.

An embodiment of the present invention will now be described with reference to the drawings.

FIG. 5 is a sectional view of a main part of the apparatus of the present invention, and in the figure, reference numeral 10 is a separating claw, which swings around a separating claw support shaft 14 so that its front end approaches and separates from the drum surface.
Further, reciprocating sliding relative to the bearing portion 16 in a direction perpendicular to the plane of the paper is similar to the conventional device. 16
is a bearing portion for the shaft 14, and is provided with a plain bearing. Reference numeral 17 denotes a plurality of notch grooves extending in the generatrix direction on the inner circumferential surface of the bearing, and a plurality of grooves are provided in the axial direction. In order to prevent the toner from escaping into the notched groove 17 due to the movement of the shaft 14 and resisting the movement of the shaft, even if the toner enters the bearing surface, the shaft-side end B of the wall forming the groove is The end portion is formed substantially perpendicular to the tangent to the shaft at the position where it abuts the shaft. Therefore, the toner adhering to the shaft is scraped off at the end B of the notch groove 17, and since the photoconductor is moved in the axial direction and in the direction of contact and separation, when the photoconductor approaches and separates, Toner can be scraped off at the corners of the groove, and then the scraped toner can be pushed out by moving in the axial direction of the photoreceptor.

As a result, there is less chance of toner getting into the bearing surface, so there is no risk of the bearing action decreasing even after long-term use, and the separation claw support shaft 14
This eliminates the occurrence of poor rocking and poor sliding.

Effects As described above, the device of the present invention eliminates malfunctions and sliding failures of the bearing due to the adhesion and intrusion of minute foreign matter such as toner, even though it adopts an extremely simple bearing configuration. In addition, since it can be prevented, there is no need for a special seal structure for bearings used in environments where fine dust is scattered, and the number of parts can be reduced accordingly. Moreover, since there is no risk of space increase, it can also be a factor in cost reduction.

Furthermore, the content of the maintenance service can be simplified.

The above-mentioned bearing device is not only effective when implemented as a support shaft bearing for the transfer paper separating claw of an electrophotographic copying machine, but also for rotating and swinging shafts used in environments where there is a risk of contamination by foreign matter. It is suitable for use as a bearing means, especially as a bearing of a mechanism operated by weak external transmission forces, thereby making it possible to extend the continuous service life of the device and to simplify maintenance and management operations.

[Brief explanation of the drawing]

FIG. 1 is a side view of the main part of the photoreceptor drum in a conventionally used electrophotographic copying machine, and FIG. 2 shows a part of the operating mechanism of the transfer paper separation claw.
Fig. 3 shows another part of the separation claw operating mechanism, which reciprocates the position of the separation claw parallel to the drum rotation axis. An explanatory diagram of the thing, a is a plan view, and b is a side view of the main part. FIG. 4 is a cross-sectional view of the bearing portion of the separation claw support shaft in the conventional device, and FIG. 5 is a view similar to FIG. 4 showing the essential parts of the device of the present invention. 1... Photosensitive drum, 10... Separation claw, 14...
... Support shaft, 16 ... Bearing part, 17 ... Notch groove,
B...notch end.

Claims (1)

[Scope of Claims] 1. A shaft that supports a plurality of separation claws, a bearing that supports the shaft, means for moving the shaft in the axial direction of the photoreceptor, and a means for separating the separation claws in the direction of the photoreceptor. In the image processing apparatus, a cutout groove extending in the generatrix direction is provided on the inner circumferential surface of the bearing part, and the shaft-side end of the wall constituting the groove is located at a position where the end comes into contact with the shaft. An image forming apparatus characterized in that the image forming apparatus is formed substantially perpendicular to a tangent line of the axis.