JPS61248072A - Device for separating paper in copying machine - Google Patents

Abstract

PURPOSE:To suppress the picture lacking width at the transfer of a toner image formed on a photosensitive drum to paper by a transfer corotron to the minimum by relativily thinning a transfer area opposed to the transfer corotron of a strip belt as compared with other parts. CONSTITUTION:The strip belt 25 is formed by a flexible stainless plate e.g. having high wear resistance and tensile strength having a prescribed value or more, a notched part 25b is formed on a position opposed to the transfer corotron 4 and Mylar 26 as a flexible film material is adhered to the strip belt 25 in accordance with the notched shape. The flexible film material relatively thinner than the stainless plate is used for a part of the strip belt 25. Consequently, the picture lacking width can be remarkably reduced. The thickness of the 'Mylar 26(R)' is preferably set to <=0.15mm.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for peeling paper from a photosensitive drum after transferring a toner image formed on a photosensitive drum of a copying machine onto paper.

As means for peeling paper such as transfer paper from the photosensitive drum of a conventional JJLi copying machine, there are widely known methods such as peeling using fingers, peeling using a peeling corotron, conveying and peeling using a gripper, and peeling using a strip belt. Among these various paper peeling means, the strip belt method is the most superior in that it stably transports the paper at a high process speed and does not cause scratches on the photosensitive drum.

As a paper peeling device that employs a strip belt method, there is one shown in FIGS. 4 to 6, for example. To explain this device, a sheet (not shown) is separated from the outer peripheral surface of the photosensitive drum 1 rotating in a clockwise direction. shoots (slope)
2.3, the toner image on the photosensitive drum 1 is transferred to this paper by the transfer corotron 4, and then the paper is guided so as to come into contact with one side of the paper and peel it off from the photosensitive drum 1. A strip belt 5 is provided.

The strip belt 5 is formed of a rigid plate made of stainless steel, for example, and is supported at both ends by a chute 3 and a support 6 fixed to the main body of the copying machine.
The peeled paper is guided and conveyed in a U-shape so as to be sandwiched between the conveyance roll 7 and the conveyance belt 8. Conveyance roll 7
rotates counterclockwise in the figure, and the pulleys 9 to 11 that drive the conveyor belt 8 rotate clockwise.
2, the paper is conveyed to a fixing device (not shown).

Problems to be Solved by the Invention However, in a paper peeling device that employs a conventional strip belt system, a strip belt 5 is inserted between the photosensitive drum 1 at one side edge of the paper facing the transfer corotron 4. Therefore, there is a problem that, for example, 8 to 15 mg of image loss occurs at the edge of the paper.

In particular, in an apparatus as shown in FIG. 4, in which the paper after transfer is peeled off from the photosensitive drum 1 using a U-turn bus method, the strip belt 5 must be made somewhat thick for strength reasons. The paper tends to lift up from the strip belt 5, and as shown in FIG. There is a problem in that the at cannot be transferred, and therefore the width of the image defect during transfer becomes large.

The present invention has been made to solve these problems, and while minimizing the width of image defects that occur at one side edge of paper during transfer, it is possible to ensure that the paper after transfer is removed from the photosensitive drum. The purpose is to peel it off and guide it in a U-turn.

In order to solve the problems of the prior art, the paper peeling device of the copying machine of the present invention includes a rigid strip that peels the paper from the photosensitive drum and guides the paper to a downstream conveyor belt. A belt is provided at a position facing at least one edge of the paper to be transported, and the paper is guided in a U-turn to the downstream transport roll by sliding the inner peripheral side of the belt curved part formed on the strip belt. A notch is formed in the transfer region of the strip belt facing the transfer corotron, and a wear-resistant flexible film material relatively thinner than the thickness of the strip belt is provided in the notch. Constructed by pasting.

The flexible membrane material in a preferred embodiment of the present invention may be any material as long as it has a certain degree of tensile strength and abrasion resistance, and its wall thickness has a tensile strength of a predetermined value or more. As long as it has wear resistance, the thinner it is, the better. This is because the thinner the flexible film material is, the smaller the width of image defects during transfer. The location for installing the flexible membrane material is
A rigid belt curved portion for peeling off the paper after transfer is formed on the downstream side of the paper conveyance path of this flexible film material at one side edge facing the transfer corotron.

According to the present invention, a strip belt for peeling off the paper after the toner image on the photosensitive drum has been transferred is provided on one side edge of the photosensitive drum facing the transfer corotron, and in the transfer area of this strip belt, By attaching a flexible film material that is relatively thinner than the strip belt, the width of image defects during transfer can be significantly reduced, and the peeling area downstream of the transfer area has a high U-turn peeling of paper can be performed reliably by the rigid belt bending section.

Back-”L-1 Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 4, both ends of a strip belt 25 are fixed to one edge of the transfer corotron 4 facing the photosensitive drum 1 by a chute 3 and a support 6 fixed to the main body of the copying machine.

The strip belt 25 is made of a flexible stainless steel plate, for example, which has good abrasion resistance and tensile strength exceeding a predetermined value, and is positioned at a position facing the transfer corotron 4 as shown in FIGS. 1 and 2. A notch 25b is formed in the notch 25b, and Mylar (trade name of DuPont) 26 as a flexible film material is adhered to correspond to the shape of the notch 25b. The Mylar 26 is made of a polyester plastic film and is attached to the strip belt 25 at opposite ends 26a and 26b.

The strip belt 25 on the downstream side of the Mylar 26 is formed with a belt curved portion 25a that turns and peels off the paper onto which the toner image on the photosensitive drum 1 has been transferred by the transfer corotron 4 in a U-shape. The paper that has been U-turned is conveyed while being sandwiched between the conveyance roll 7 and the conveyance belt 8, and then conveyed by the conveyance belt 12 to a fixing device (not shown).

According to experiments conducted by the present inventors, the thickness of the stainless steel plate 25 used as the strip belt was 0.2 m, and the Mylar 26
When the wall thickness of the stainless steel plate 25 was set to 0.15 m or more, the width of the image defect during transfer was 5 or more frames, whereas when the stainless steel plate 25 was set to the same thickness of <0.2 m. m and the thickness of Mylar 26 is 0.05m
As a result of conducting an experiment under the following setting conditions, the width of the image defect was measured to be 0.5 mg+. From the results of this experiment, it was found that it is preferable to set the thickness of the Mylar 26 to 0.15 mm or less. In addition, the conventional wall thickness 0°2 shown in Fig. 5
When the width of the image defect was measured using the shoe strip belt 5, it was 9 IuR from the end of the belt. These experimental results show that when using a flexible membrane material that is relatively thinner than the stainless steel plate in a part of the strip belt compared to a conventional strip belt made only of stainless steel plates, the width of image defects is significantly reduced. It became clear that it could be done.

As another example, as shown in FIG.
Both ends 26a and 260 of 6 may be bonded to each other on the same surface, and the flexible membrane material used in the present invention is as follows:
The material is not limited to Mylar used in the examples, but any other flexible material with good wear resistance, tensile strength, etc. may be used. In addition, the range in which the thin flexible film material of the present invention can be attached is limited to the width of the strip belt in the width direction through which the paper passes (for example, 4 to 7 M
) and paper feed skew (for example, 2 to 3 shoes), and it is desirable to set the length in the longitudinal direction of the strip belt to a length corresponding to the transfer area (the opening width of the transfer corotron).

In this way, by providing a flexible film material relatively thinner than the thickness of the belt in the cutout portion of the strip belt, the width of image defects during transfer can be minimized. As a conventional technique, a method has been proposed in which a pressing member is provided that pinches the paper and presses the paper from the opposite side to the photosensitive drum in order to prevent image defects caused by lifting of the paper from increasing in width. In this case, there is a drawback that the pressing member causes scratches on the photosensitive drum and black streaks are formed on the paper. In contrast, the present invention has the advantage that no damage such as scratches occurs on the photosensitive drum, and no stains such as black streaks occur on the irises.

Effects of the Invention According to the present invention, it is possible to minimize the width of image defects when a toner image on a photosensitive drum is transferred onto a sheet of paper by a transfer corotron, and to ensure that even when the sheet is conveyed at high speed. The paper can be peeled by making a U-turn, and peeling mistakes can be reliably prevented. The present invention has the advantage that there is no damage to the photosensitive drum and no stains such as black streaks on the paper.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view showing the main parts of an embodiment of the present invention, Fig. 2 is a schematic side view of Fig. 1, and Fig. 3 corresponds to Fig. 2 without showing the main parts of another embodiment. FIG. 4 is a schematic diagram of the configuration of a general paper peeling device; FIG. 5 is a schematic plan view corresponding to FIG. 1 showing a conventional example; FIG. 6 is a schematic diagram of FIG. 5. The side view and FIG. 7 are explanatory diagrams for explaining the operation of the conventional example. 1: Photosensitive drum 2, 3: Chute 4: Transfer corotron 7: Conveyance roll 8: Conveyance belt 25: Strip belt 25a:
Belt curved portion 25b: Notch portion 26: Flexible membrane material (Mylar)

Claims (1)

[Claims] A rigid strip belt for separating the paper from the photoreceptor and guiding the paper to a downstream conveyance means is provided at a position facing at least one edge of the paper to be conveyed, and a belt curved portion is formed on the strip belt. In a paper peeling device for a copying machine that guides paper to a downstream conveying means by sliding the inner peripheral side of the strip belt, the transfer area facing the transfer corotron of the strip belt is relatively separated from other parts. A paper peeling device for a copying machine characterized by a thin wall.