JPS6279485A - Transfer device - Google Patents

Abstract

PURPOSE:To improve the adhesion and transfer performance of transfer paper and to take a uniform copy on the transfer paper by improving the shape of the surface of a transfer material support and eliminating the formation of an air layer between the transfer material support surface of the support and the transfer material. CONSTITUTION:A transfer drum 9 is arranged on the peripheral surface of the photosensitive drum 4 of the transfer device and this drum 9 consists of the transfer paper support 9-1 which forms the peripheral surface of the drum 9 by using a dielectric film and a ring body 9-1 which holds the film. When those support 9-1, transfer paper S-1, and drum 4 where toner T having passes respective image formation positions is stuck on the peripheral surface advance as shown by an arrow to pass a transfer position, the transfer paper S-1 is attracted to the support 9-1 by a transfer charger 14 to come into contact. Then, an air layer A formed between the support 9-1 and transfer paper S-1 is eliminated where the charger 14 and drum 5 contact each other, thereby copying a uniform image on the transfer paper S-1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a transfer device in an electrophotographic copying machine.

[Prior art] No. 41i! 1 is an example of a known transfer device (Utility Model Laid-Open No. 1983-1991), which is equipped with a transfer material (paper) support that is endless in the transport direction and a means for applying transfer corona discharge from the back surface of the transfer material support at the toner image transfer position. 88656), in which 4 is a photosensitive drum, 9 is a transfer drum, and 9 is a
-1 is a transfer paper support film; 9-2 is a link (frame) body for supporting the transfer paper support film; 14 is arranged on the back side of the support film 9-1 facing the transfer position;
A transfer corona discharger (charger) T is toner for forming an image, which is attached to the surface of the transfer drum 4 and transferred to a transfer position. S-t is a transfer paper that has been exposed to moisture or has become wavy due to being too dry.

A is an air layer, and the support film 9-1 is a general-purpose insulating film with a smooth transfer paper support surface, so when copying is performed using the transfer paper S-1, which has become wavy due to moisture or dryness, At the transfer position, the area around the convex part of the transfer paper S-1 is first attracted and adhered to the photoreceptor 4 due to the Coulomb force of the transfer corona, so that the transfer paper S-1 passes through the transfer position with an air layer A formed between them. This results in the inconvenience that some parts cannot be transferred.

] - In order to prevent the above-mentioned inconvenience, a means as shown in a perspective view and a partially enlarged sectional view in FIGS. 5(a) and 5(b) has been proposed (see Japanese Patent Laid-Open No. 57419673). That is, as shown in the figure, a method is known in which the transfer paper support 9-1 is supported by a mesh screen on the back side of an insulating film to improve shape retention and prevent the formation of an air layer at the transfer position. However, during transfer, as shown in Figure 5 (tl), the transfer efficiency of the part that is in the shape of the mesh line is different from that of the part using only film, so it is difficult to copy with uneven transfer. There is a risk that it will become.

[Objective] The present invention improves the problems inherent in electrophotographic copying machines equipped with the above-mentioned transfer device, and provides an Mlffl that does not cause the above-mentioned transfer failure during copying. The purpose is to

[Structure] In order to achieve the object mentioned above, the present invention includes a transfer material support member that is endless in the moving direction, and a means for applying transfer corona discharge from the back surface of the transfer material support member at a toner image transfer position. In a transfer device, the surface of the transfer material support is shaped so that when the transfer material supporting surface of the support comes into contact with the transfer material, the two can be brought into close contact without forming an air layer between the two. Hereinafter, the present invention will be explained according to embodiments shown in the drawings.

Embodiment FIG. 1 is a schematic configuration diagram showing an example of a copying machine equipped with a transfer device according to the present invention.To outline its operation, in the figure, an object (original) 2 on an original placing glass 1 is placed as follows. The photoreceptor drum 4 is illuminated with light by the illumination optical device 3, and the electrostatic latent image is rotated in the direction of the arrow and conveyed to the developing device 5, where it is developed with toner and made visible. On the other hand, the transfer paper S fed from the cassette 6 is sent toward the transfer tram 9 via a paper feed roller 7 and a pair of registration rollers 8, and is held by a sheet clipper 11 that can be opened and closed provided on the circumference of the drum 9. The leading edge is held and transferred along the surface of the transfer drum in the direction of the arrow. In this way, the leading edge of the visible image forming area on the drum 4 and the leading edge of the transfer paper S on the circumferential surface of the drum 9 overlap at the same timing at the transfer position 13,
The two pass through position 13 one after another without contacting each other, but at this time, the transfer charger 14 provided at the back of the transfer drum surface is activated and transfers the visible image on the photoreceptor tram 4 to the transfer paper S side. The transfer paper S is transported without being transferred.

After this transfer, the residual toner on the ram 4 is removed by the cleaning group @l.

In this copying machine, electrostatic latent images are formed on the photoreceptors 1 to 4 according to the number of color separations, and each time the image is developed and visualized using a 1-toner of a different color. This is transferred, the transfer tram 9 is rotated by the number of color separations, the visible image of the color of the mold is superimposed on one transfer paper, and when the last transfer is completed, the gripper 11 moves the transfer paper peeling claw 16 When the transfer paper S reaches the vicinity of , the gripper II is opened while the separating Nayasha 15 assists in separating the leading edge of the transfer paper S, and the leading edge of the transfer paper S is lifted and separated from the circumferential surfaces of the transfer rams 1 to 9. Next, the leading edge of the transfer paper S rests on the peeling claw 16, and
- Of the 27 processes in which the transfer paper S is separated from the ram circumferential surface and then discharged and stored in the 1-ray 19 via the fixing device @ 17 and the discharge roller pair 18, the transfer charger 14 1- on the photoreceptor drum 4 when passing through.
In addition to the action of transferring the color image onto the transfer paper, there is also an action of adhering the transfer paper S to the dielectric film on the circumferential surface of the transfer tram by the Coulomb force during corona discharge, and the transfer paper S and the transfer 1-ram 9 etc. Because it starts to rotate as one,
The force that pulls the transfer paper as it passes the transfer position is Gu II
The result is twitching + electrostatic adsorption force, which is much greater than when only the clipping force is used.

Figures 2 (a) and (, b) are detailed views of the transfer tram 9 used in the copying machine, in which (d) is an overall perspective view, and (bl) is an exploded parts view. 9 is a photosensitive drum, and 9-1 is a transfer paper support forming the peripheral surface of the transfer drum 90, which is made of a dielectric film.

9-2 is 1 for holding the support film 9-1.
11 is a gripper for the transfer paper S.

FIG. 3 shows an enlarged sectional view of the main parts of the transfer drum 9. In the figure, 4 is a photosensitive tram, and T is a toner 5S-1 that has been left in the air for a long period of time and absorbed moisture in the air. A is an air layer (air cap), 9 is a transfer tram, 9-] is a transfer paper support, and an insulating film with a rough surface on the support side of the transfer paper, 9 -2 is a support base for the insulating film 9-1, a link body, and 14 is a transfer charger.

Now, the transfer paper support 9-■, the transfer paper S-t, and the photosensitive drum 4, etc. with the 1-ner T adhered to the circumferential surface pass through the transfer positions and advance in the direction of the arrow and pass through the transfer positions. At this time, the transfer paper S-t is absorbed and adhered to the support 9-1 by the transfer charger 14 by Coulomb force, and at the same time, the toner T adsorbed on the photoreceptor for image formation is also transferred onto the transfer paper S-1. The transfer process is completed when the transfer process is completed.
Since the surface of the support 9-1 is roughened, when the transfer paper is adsorbed to the support, the air A contained in the bulge width of the transfer paper S-1 is drawn to the support 9-1. When it is attached, it escapes in the direction of the arrow, and when it passes the opposite side of the transfer charger 14, it can come into close contact.

If the surface of the support 9-1 is smooth as shown in Figure 4, the air layer A can escape as described above, and the transfer process is passed with the air cap A still formed. Therefore, it is not possible to adsorb the 1 henna T on the photoreceptor, resulting in defective transfer areas, making it impossible to obtain uniform copies.

Conventionally, the smooth surface of the insulating film used as the transfer paper support 9-1 has a surface roughness of 0.01-0.05μ.

In this example, good results were obtained when the transfer paper supporting surface side was roughened to about 0.2 to 5 μm. Furthermore, even when one surface was roughened, the same effect as described in Section 2 was obtained.

Even if the surface roughness was set to 5 tt or more, the above-mentioned effect was observed, but clogging with toner increased, so we refrained from using it.

"effect" As described above, when using the device of the present invention, (1) Transfer performance is improved by improving the adhesion of the transfer paper.

(2) Transfer is possible even when using curly transfer paper due to moisture absorption or excessive dryness, and uniform, high-quality copies can be obtained.

Compared to conventional devices such as 6.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a copying machine equipped with a transfer device of the present invention, and FIGS. 2(a) and (b) are an overall perspective view and an exploded view of the transfer drum related to the copying machine. partial diagram,
Fig. 3 is an enlarged sectional view of the main part of the transfer drum of the device of the present invention, Fig. 4 is an enlarged sectional view of the main part of the known transfer device, and Fig. 5 Ca)
and (Ll) are a perspective view and a partially enlarged sectional view of a transfer drum of another known transfer device. 4... Photosensitive drum, 9... Transfer drum, 9-
1... Transfer material support, 9-2... Link body, 14.
...Transfer charger, T...toner. S-1... Transfer paper 5 A... Air layer.

Claims (2)

[Claims] (1) In the moving direction, an endless transfer material support and a means for applying transfer corona discharge from the back surface of the transfer material support at a toner image transfer position are provided, and the transfer material supporting surface of the support is in contact with the transfer material. A transfer device characterized in that the support surface is treated so that the two can be brought into close contact without forming an air layer between the two. (2) The transfer device according to claim 1, wherein the transfer material support is composed of an insulating film having a rough surface on the transfer material support side.