JPS60208782A - Separating claw device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To prevent the front edge of a separating claw from contacting transfer paper when the separating claw is released by providing a control member which controls the floating range of the separating claw so that the front edge of the separating claw separated in engagement with an engaging member does not reach a transfer paper conveyance path. CONSTITUTION:The control member 15 which locks the end part of the separating claw 8 to control its unnecessary rotation due to inertia is provided to one terminal of a cleaning case 13. This control member 15 may, however, be provided at another proper position. A proper engaging member which does not engage a pin 10 with a groove 9, but operates similarly may be provided as a turning means for the separating claw. This invention prevents the separating claw from rotating by inertia until it contacts transfer paper even if the separating claw is separated from a photosensitive body when the front end of the transfer paper is passed while the contacting force between the separating claw and the surface of the photosensitive body is reduced, so that the transfer paper is never stained with toner sticking on the front edge of the separating claw.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a separation claw device for separating transfer paper from the surface of a photoreceptor in an electrophotographic copying machine.

As a means of separating the transfer paper from the photoreceptor, there is a known method in which the charge is removed from the transfer paper by corona discharge or the like after the transfer, and the adhesive strength is weakened and the paper is peeled off. Since it is easily influenced by the environment, it is common to use a separation claw as an auxiliary means. However, if the tip of the separating claw is kept in constant contact with the surface of the photoreceptor, scratches will occur on the surface of the photoreceptor. In order to avoid problems on the photoconductor, there are methods in which the separation claw is brought into contact with the photoconductor only when the leading edge of the transfer paper passes through, and separated at other times. There are known methods for preventing the occurrence of scratches on the body.

When using a λ52Se photoreceptor, it has a lifespan of 40,000 to 10,000 sheets, taking into account deterioration due to normal copying cycles, but in order to prevent scratches caused by 1-separation nails until the lifespan listed below, our According to the test, even if both contact/separation and axial movement are employed, the contact force between the tip of the separating claw and the surface of the photoreceptor is preferably below [g−f].

In general, the 1-separation claw is made of hardened steel, although part of its holder is made of resin, and in order to keep it sharp for a long time, it has a large mass. Therefore, it is difficult to reduce the moment of inertia.

Therefore, as a specific means for moving the separation claws toward and away from each other under the condition of a contact force of 1g-f or less, the separation claws are moved in the direction in which they contact the photoreceptor by a spring or a weight, and the position in the above direction is adjusted by, for example, separating the separation claws. By providing an engaging member such as the engagement between a pin set on the claw support shaft and a groove provided in the separation claw boss, and rotating this support shaft to move the separation claws toward and away from each other, the pin is released. If the inertia of the separation claw is larger than the load 1g-f at the tip of the separation claw, the separation claw will be released too quickly, and the tip of the separation claw will come into contact with the transfer paper being separated and transferred, causing the separation claw to The toner adhering to the transfer paper will crumble into small pieces, causing the image on the transfer paper to be distorted.

The present invention aims to prevent such contact between the tip of the separating claw and the transfer paper when the separating claw is released.

1st commandment Hereinafter, the present invention will be explained according to embodiments shown in the drawings.

FIG. 1 is a sectional view showing the structure of a separating claw device in an electrophotographic copying machine, and FIG. 2 is a plan view showing the structure of a separating claw and a support shaft.

In FIG. 1, the description of the charger, exposure device, developing device, etc. is omitted, or the toner image formed on the photoreceptor 1-1 is transferred from the transfer paper conveyance roller 2.degree. Board 3
A fixing device (not shown) in which the transfer paper is transferred by a transfer charger 4 and separated from the photoreceptor I to the ram L by a separation charger 5 and moved along a transfer paper guide 6. As an auxiliary means for separation, a separation claw 8 loosely fitted onto the separation claw support shaft 7 is provided.

This separation claw 8 has I#! as shown in the figure. 9 is provided, which engages with a pin (engaging member) 10 installed in the spindle 7 as an engagement member between the separating claw 8 and the spindle 7, and a second
As shown in the figure, there is a separation claw 8 between the support shaft 7 and the separation claw 8.
A spring 11 is provided to bias the photoreceptor drum 1 toward the photoreceptor drum 1. Therefore, the separation claw 8 is rotatable by being carved into the support shaft 7 by the amount of play between the groove 9 and the pin 10. In the state shown in FIG. 1, the tip of the separating claw 8 is urged against the photosensitive tram 1 by the force of the spring 11. And the spindle 7
As a result of the clockwise rotation, the pin IO engages with the end *9a of the groove 9, as shown in an enlarged view in FIG. 3, and the separating claw 8 is separated from the surface of the photoreceptor drum 1.

In addition, in the figure, the reference numeral 12 is a cleaning auxiliary charger,
13 is a cleaning case, and 14 is a cleaning blade.

By the way, in a copying machine, when no transfer paper is being fed, the tip 8a of the separating claw 8 is separated from the photosensitive drum 1 as shown in FIG.

When the copying operation starts and the transfer paper is fed (usually when the leading edge of the transfer paper reaches the 50++o position in front of the separation claw),'?
! j. The spindle 7 is rotated counterclockwise by a certain angle by the magnet, and the separating claw 8 comes into contact with the photoreceptor l by the force of the spring, as shown in the fourth figure. Of course, the force may be applied by the action of a weight instead of a spring.

When the leading edge of the transfer paper passes the separation charger part (for example, when the leading edge of the transfer paper is fed 100+nn behind the separation claw), the electromagnet stops operating and the support shaft 7 is stopped by a spring or the like.
The pin lO is returned to the position shown in the third figure, but the separation claw 8, which is pushed against the photoreceptor surface with a weak force, further rotates in the R1 direction due to its inertia, so that the transfer paper passing through it This will cause the toner on the separation claw to get onto the transfer paper.

In order to prevent such stains on the transfer paper, in this embodiment, as shown in FIG.
3 is provided with a regulating member 15 that engages with the end of the separating claw 8 to prevent it from rotating more than necessary due to its inertia.

However, this regulating member 15 may be provided at any appropriate location. In addition, i#! is used as a means for rotating the separation claw.
Instead of the engagement between 9 and the pin 10, an appropriate engagement member having a similar function may be provided.

According to the present invention, even if the separation claw is separated from the photoreceptor when the leading edge of the transfer paper passes with the contact force between the separation claw and the photoreceptor surface being weak, the separation claw will not be affected by inertia. Since the separator does not rotate so much as to come into contact with the transfer paper that is being separated and transported, the transfer paper will not be contaminated by toner adhering to the tip of the separation claw.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of the separation claw device in an electrophotographic copying machine, FIG. 2 is a plan view showing the structure of the separation claw and the support shaft, and FIGS. These are enlarged views showing the relationship between the claw and the photoreceptor drum, with Fig. 3 showing the separated state and Fig. 4
The figure shows a state of contact. l...Photosensitive drum, 4...Transfer charger, 4
... Separation charger, 6... Transfer paper guide, 7...
・Separation claw support shaft, 8...Separation claw, 9...Groove, 10.
...Pin (engaging member), 11...Spring, 13
... Cleaning case 15 ... Separation claw rotation regulating member. Agent Patent Attorney Makoto Kon Figure 1

Claims (1)

[Claims] The separation claw is biased by a spring or weight so as to come into contact with the photoreceptor surface, and is loosely fitted onto the separation claw support shaft.The separation claw is further rotated by rotating the separation claw support shaft so as to separate the separation claw from the photoreceptor surface. An engaging member that rotates against the bias is provided on the separation claw support shaft, and the separation claw is arranged so that the tip of the separation claw separated by engagement with the engagement member does not reach the transfer paper conveyance path. 1. A separating claw device for an electrophotographic copying machine, characterized in that a regulating member is provided for regulating the range of movement of the electrophotographic copying machine.