JPS6377073A - Transfer device - Google Patents

Abstract

PURPOSE:To improve picture quality by providing a control plate which controls an area charged electrostatically by a transfer charger to in front of a point where a transfer form contacts the surface of a photosensitive drum in a rotating direction to a form conveyor guide for the transfer form, and composing the control plate of an insulating member. CONSTITUTION:The point where the transfer form A is guided by the form conveyance guide 4 to contact the photosensitive drum 1 is denoted as a contact point P and when the transfer form A is charged electrostatically before the contact point P in the rotating direction of the photosensitive drum, no toner is scattered over the transfer form. For the purpose, the control plate 5 is arranged on the opposite side of a flat plate 41 from the photosensitive drum 1. Therefore, a corona ion flow generated by applying a high voltage to a charger wire 3 is not projected behind the contact point P where the transfer form A contacts the photosensitive drum 1, so the transfer form which does not contact the photosensitive drum 1 is never charged electrostatically. Consequently, toner on the surface of the photosensitive drum 1 is never attracted by the transfer form which does not contact the photosensitive drum to scatter over the transfer form.

Description

DETAILED DESCRIPTION OF THE INVENTION +8+ Industrial Application Field This invention relates to a transfer device for transferring toner on the surface of a photoreceptor drum onto a conveyed transfer sheet in an electrophotographic copying machine or the like.

fb) Conventional technology In an electrophotographic copying machine, an electrostatic latent image is formed on the surface of a photoreceptor drum, triboelectrically charged toner is electrostatically attached to this electrostatic latent image, and further, A toner image is formed on the transfer paper by electrostatically transferring the toner to the transfer paper whose back side is charged by a corona ion flow. Figure 2 shows the above process.
FIG. 2 is a diagram illustrating the configuration of a transfer device that executes a process of transferring toner to transfer paper. A charger box 2 is disposed opposite the photosensitive drum 1. A charger line 3 is stretched within the charger box 2. A high voltage is applied to this charge line 3 to generate a corona ion flow. A transfer sheet is conveyed from the paper conveyance guide 4, and as the back surface of the transfer sheet is charged by the corona ion flow as described above, toner is transferred from the photoreceptor drum 1 onto the surface of the transfer sheet.

(C) Problems to be Solved by the Invention When transferring toner to transfer paper in this way, it is possible that the toner will be transferred to the transfer paper after the transfer paper is brought into contact with the surface of the photoreceptor drum. desirable. This is because the toner image formed on the surface of the photoreceptor drum can be reliably transferred to the transfer sheet as it is by bringing the transfer sheet into contact with the photoreceptor drum.

However, in the conventional transfer device as described above, the second
As shown in the figure, before the transfer paper A comes into contact with the surface of the photoreceptor drum 1, the back surface of the transfer paper A is charged by the corona ion flow, and the toner on this charged area and the surface of the photoreceptor drum 1 is charged. A Coulomb force is generated between the transfer paper and the transfer paper, and the transfer paper may fly to the charged area. As a result, toner scattering appears on the image formed on the transfer paper, causing a significant deterioration in image quality.

This invention improves image quality by preventing toner from scattering on the image formed on the transfer paper by preventing the transfer paper from being charged before it contacts the surface of the photoreceptor drum. The purpose is to improve.

ld) Means for Solving the Problems The transfer device of the present invention has a regulation that regulates the charging area by the transfer charger to be forward in the rotational direction of the photoreceptor drum than the point where the transfer paper contacts the surface of the photoreceptor drum. board,
The present invention is characterized in that it is provided on a paper conveyance guide for transfer paper, and that the regulation plate is made of an insulating member.

(Q) Effect In this invention, the region charged by the transfer charger is regulated by a regulating plate provided on the paper urethral guide of the transfer paper, and only the area in front of the point where the transfer paper contacts the surface of the photoreceptor drum is charged. It becomes like this. Therefore, the area of the transfer paper after it is in contact with the photoreceptor drum will not be charged, and toner will not fly to the transfer paper.

Furthermore, since the regulation plate is made of an insulating material, leakage may occur between the charger wire and the regulation plate, and excessive current may flow between the charger wire and the photoconductor drum. There is no possibility that the current will drop and the transfer paper will become less likely to be charged.

(f) Embodiment FIG. 1 is a schematic diagram of a transfer device according to an embodiment of the present invention.

The photosensitive drum 1 is a cylindrical body having a photoconductive layer formed on its surface, and is rotatable in a clockwise direction.

A charger box 2 is disposed opposite the photosensitive drum 1. The charger box 2 is made of a conductive member such as metal, has an L-shaped cross section, and is connected to the photoreceptor drum 1.
The side facing the paper conveyance guide 4 and the side facing the paper conveyance guide 4 are open. A charger line 3 is stretched around the charger box 2 along the rotation axis of the photosensitive drum 1. A high voltage is applied to this charge line 4, and a corona ion flow is generated.

Like the charger box 2, the paper conveyance guide 4 is also made of a conductive member such as metal. The end of the paper conveyance guide 4 is slightly bent so as to face the photoreceptor drum, forming a flat piece 41. The transfer paper A is guided by the paper transport guide 4 and is transported so as to come into contact with the photosensitive drum 1 . Here, the point at which the transfer paper A is guided by the paper conveyance guide 4 and comes into contact with the photoreceptor drum 1 is defined as a contact point P. If the transfer paper A is charged before the contact point P (on the left side in the figure) in the rotational direction of the photosensitive drum, the phenomenon of toner flying onto the transfer paper does not occur.

Therefore, a regulating plate 5 is provided on the side of the flat piece 41 facing the photosensitive drum 1. The regulating plate 5 is made of an insulating material such as polyethylene terephthalate (PET), and prevents the corona ion flow from the charge line 3 from being irradiated after the contact point P (on the right side in the figure).

With the above configuration, the corona ion flow generated by applying a high voltage to the charger line 3 is transmitted after the contact point P where the transfer paper A contacts the photoreceptor drum 1 (on the right side in the figure). Because it is not irradiated, photoreceptor drum 1
Transfer paper that is not in contact with the transfer paper will not be charged. Therefore, the toner on the surface of the photoreceptor drum 1 will not be attracted to the transfer paper that is not in contact with the photoreceptor drum and will not jump to the transfer paper (and the toner will not fly off to the transfer paper).

Furthermore, since the regulation plate 5 is made of an insulating material such as PET, leakage may occur between the charger wire 3 and the regulation plate 5, or excessive current may flow between the charger wire and the regulation plate. The charger line-photosensitive drum current does not decrease and the transfer paper becomes difficult to be charged.

Furthermore, in this embodiment, the regulation plate 5 is disposed on the photosensitive drum 1 side of the paper conveyance guide 4 so that the regulation plate 5 does not come too close to the charger line 3, so that the impedance of the charger line becomes too high. Nor.

(g1 Effect of the invention According to this invention, the charging area by the transfer charger is regulated by the regulating plate provided on the paper conveyance guide of the transfer paper, and only the area in front of the point where the transfer paper contacts the surface of the photoreceptor drum is charged. Therefore, the area of the transfer paper after it is in contact with the photoreceptor drum is not charged, the toner does not fly to the transfer paper, and the toner image formed on the transfer paper becomes No toner scattering occurs.

Furthermore, since the regulation plate is made of an insulating material, leakage may occur between the charger wire and the regulation plate, and excessive current may flow between the charger wire and the photoconductor drum. There is no possibility that the current will drop and the transfer paper will become less likely to be charged.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic structure of a transfer device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a schematic structure of a conventional transfer device. 3-Charger line, 4-Paper transport guide, 5-Regulation plate, P-Contact point (between transfer paper and photoreceptor drum).

Claims (1)

[Claims] (1) A regulation plate is provided on the paper conveyance guide of the transfer paper, which regulates the charging area by the transfer charger forward in the rotational direction of the photoconductor drum from the point where the transfer paper contacts the surface of the photoconductor drum. A transfer device characterized in that a regulation plate is made of an insulating member.