JPS5898765A - Exfoliating device of transfer paper - Google Patents

Abstract

PURPOSE:To avoid the damage on the surface of a photosensitive drum, by using an elastic member which has two contact parts to decide a plane crossing the cylindrical surface of the photosensitive drum and set at the oustide to the original reference edge. CONSTITUTION:An electrophotographic copying machine uses a cylindrical photosensitive drum 6 and conveys a transfer paper 7 with its single side defined as the original reference edge 8. An exfoliating pawl 9 is set near the edge 8 and to be opposite to the drum 6, and then a stepped contact member 14 is attached on the lower face of a basement 11. The member 14 is made of a flexible member such as urethane rubber, etc. In such a way, the tip of the pawl 9 is positioned and held to the drum 6 by means of the contact member 14. This can prevent the damage on the surface of the drum 6 with a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer paper peeling device for an electrophotographic copying machine.

Generally, in an electrophotographic copying machine, as shown in FIG. 1, a peeling claw (3
), which is rotatable about a shaft (4) and biased by a spring (5), so that its tip is brought into contact with the photosensitive drum (1). Here, in order to prevent or reduce damage to the photoreceptor drum caused by the peeling nail, conventional methods
Various measures are being taken. For example, JP-A-49-1
According to Japanese Patent No. 02352, an air cushion is used to hold the tip of a peeling claw in a small gap with respect to the surface of a photoreceptor drum. However, it is inevitable that the device will become larger and more complicated due to the need for air pressure feeding means, pressure adjustment means for maintaining an appropriate gap, and the like.

Furthermore, according to Japanese Patent Application Laid-open No. 101531/1989, a mechanism for finely adjusting the position of the tip of the peeling claw is disclosed, but in the case of this method, due to the component configuration of the adjustment mechanism, adjustment work must be performed and Even if adjustments were made accurately, it would be difficult to maintain proper contact pressure and contact position over a long period of time.
According to Japanese Patent No. 1-43136, pressure is applied to extend the life of the photoreceptor drum by making the contact position of a peeling claw with respect to the photoreceptor drum variable. If a peeling nail that is harder than the photosensitive layer comes into contact with the photosensitive layer, the range in which the photosensitive drum can be moved in the axial direction is limited, and therefore the life of the photosensitive drum cannot be expected to be extended to the extent shown above.

The present invention has been made in view of these points, and provides a transfer paper that can prevent damage to the surface of the photoreceptor drum by keeping the tip of the peeling claw in a minute gap with respect to the surface of the photoreceptor drum with a simple structure. The purpose is to obtain a peeling device.

In the present invention, the transfer paper is peeled off from the photoreceptor drum by the tip of the peeling claw, and the transfer paper is peeled off from the photoreceptor drum through a contact member made of a flexible member such as urethane rubber and in contact with the photoreceptor drum. The peeling claw is held at a small gap with respect to the photoreceptor drum, so that the photoreceptor drum is not damaged.

An embodiment of the present invention will be described based on FIGS. 2 to 6. First, the electrophotographic copying machine to which this embodiment is applied is
A cylindrical photoreceptor drum (6) is used, and one side of the transfer paper (7) is used as the original reference edge (8) to carry the transfer paper (7), and the paper is peeled off regardless of the size of the transfer paper (7). A peeling claw (9) is arranged along the vicinity of the document reference edge (8) to face the photosensitive drum (6). This peeling claw (9) is made of plastic, metal, etc. and has an acute tip that performs a peeling action. (6
) is integrally formed with a base a) extending upstream in the rotational direction of the photoreceptor drum (6), which is rotatable around a shaft (6) and whose tip oQ@ is connected to the photoreceptor drum (6) by a spring. It is biased in the direction of contact. Accordingly, contact members α→, which are formed at different levels, are attached to the lower surface of the base α. This contact member α→ is formed of a flexible member such as urethane rubber, and has a contact portion (b) that contacts the photoreceptor drum (6) K in a generatrix shape upstream in the rotational direction and a contact portion (b) that contacts the photoreceptor drum (6) K in the downstream direction in the rotational direction. A contact portion αQ that contacts in a generatrix shape or a dot shape is provided near the tip αQ, and one plane Sl that intersects with the cylindrical surface of the photoreceptor drum (6) is determined by the plane connecting the contact portions (G) 69. is set to be Under the contact member α◆ having such contact portions (B) and (G), the tip (to) of the peeling claw (9) is located on the tangent line LI at the contact portion (to).
They are positioned in close proximity to each other and spaced apart by dJ-.

As shown in Fig. 6, the base C1m has a free hole α force formed with the shaft (6) and the central protrusion (to) is engaged, so that it can be displaced vertically and horizontally. It is supported as such.

In such a configuration, the position of the peeling claw (9) with respect to the photoreceptor drum (6) is determined by the contact member (14). That is, the contact member α under the biasing force of the spring (LIK)
◆ comes into contact with the photoreceptor drum (6) K at its contact part o4 (2) and its flat WJft is determined, so the tip (g) of the peeling claw (9) also moves away from the contact part α0 by dL while also touching the contact part (
(b)) is positioned on the tangent 1i1Lx including 1i1Lx. Therefore,
Due to the curvature of the cylindrical surface of the photoreceptor drum (6) at the tip αq, the photoreceptor drum (6) is held in a minute gap with respect to the surface of the photoreceptor drum (6). Since it is displaced from side to side and supported in a hanging manner, the contact member α◆
is the photoreceptor 1. at its contact portion (b) (b). Ram (
6), the positioning of the tip (G) is also accurate.

Under such conditions, a transfer operation and a peeling operation of the transfer paper (7) are performed as the photoreceptor drum (6) rotates, but the tip αQ of the peeling claw (9) touches the photoreceptor drum (6). Since they are held very close together, the transfer paper (7) is reliably peeled off. In this case, since the photoreceptor drum (6) K is only in contact with the contact member α◆ made of urethane rubber, the surface of the photoreceptor drum (6) will not be damaged. It is clear from the fact that even if the processed edges are brought into contact with the photoreceptor drum, there is very little mechanical adverse effect on the surface of the photoreceptor drum. and,
The peeling claw (9) itself may also be made of urethane rubber, but
As in this embodiment, the peeling claw (9), which substantially acts on the peeling action, is made of plastic or metal, so that it can be used for a long period of time to prevent the peeling of the transfer paper (7). It can be done with certainty. Furthermore, the vicinity of the contact portion (B) is located upstream in the rotational direction from the tip (G), but since that portion is located outward from the document reference edge (8), it is difficult to peel off. It does not have any negative impact.

By the way, when the contact member <141 is formed of a flexible member such as urethane rubber as in this embodiment, the peeling claw (
9) due to inappropriate pressing force applied to the transfer paper (7), conveyance resistance force of the transfer paper (7) that is received at the leading edge when the transfer paper (7) is peeled off, etc.
There is a possibility that the aforementioned minute gap cannot be maintained between the tip and the surface of the photoreceptor drum (6), but even in such a case, the load applied to the peeling claw (9) K is The load on the surface of the photoreceptor drum (6) is distributed not only at the tip but also at other contact parts (to) αQ, etc. Therefore, as in the conventional example shown in FIG. ) is in contact with the surface of the photoreceptor drum (6), the damage to the surface of the photoreceptor drum (6) is extremely small.

Furthermore, when urethane rubber is used as the contact member α◆, the frictional force with the surface of the photoreceptor drum (6) becomes large depending on the hardness of the rubber and the contact method. There are cases where the machine cannot be used. In this regard, in the case of a wet-type electrophotographic copying machine, the frictional force is reduced by the action of the solvent attached to the surface of the photoreceptor drum, and the constraints on use are relaxed, so this embodiment This can be said to be particularly advantageous for wet-type electrophotographic copying machines.

Note that FIG. 7 shows a modification.

According to the present invention, as described above, the flexible member is formed into a photoreceptor drum! ! The tip of the stripping claw is positioned and held with respect to the photoreceptor drum in a predetermined positional relationship using a contact member having two contact parts. The peeling operation can be performed while being held in a minute gap, thereby preventing damage to the surface of the photoreceptor drum.

[Brief explanation of drawings]

Fig. 1 is an II side view showing a conventional example, and Fig. 2 is an 11 side view of the present invention
! FIG. 3 is a perspective view showing the embodiment, FIG. The figure is a perspective view showing a modification. 6... Photosensitive drum, F... Transfer paper, 8... Document reference edge, 9... Peeling claw, 10... Tip, 14...
Contact members, 15-16...Contact parts Applicant: Ricoh Co., Ltd.

Claims (1)

[Claims] In an electrophotographic copying machine that uses a cylindrical photoreceptor drum and transports a transfer paper with one side of the drum as the document reference edge,
A contact member formed of a flexible member is provided which is disposed outward from the document reference edge and has two contact portions that determine one plane that intersects with the cylindrical surface of the photoreceptor drum. The tip of the peeling claw, which is held and arranged along the vicinity of the reference edge of the document, is located close to and on a tangent to the contact portion, which is located upstream from the tip of the peeling claw in the direction of rotation of the photoreceptor drum. Transfer paper peeling device.