JPS62124580A - Corona transfer device - Google Patents

Abstract

PURPOSE:To reduce the scattering of toner and to obtain high picture quality by arranging a transfer guide plate which has an image carrier side made of a conductive member and a transfer charger side made of an insulating member between a transfer charger and an image carrier so that the transfer material entry gate part of the transfer charger is covered. CONSTITUTION:The transfer charger 101 is provided with insulating members 18 and 19 on the internal surfaces of both side walls, so corona discharge is divided into a flow in a direction 20 to a transfer material 13 and a flow in a direction 21 to the bottom surface of a shield case 17 serving s a back electrode and never flows sidewise wastefully, so that a corona discharge current directed strongly to the contact area of the transfer material 13 is obtained efficiently. Further, a charge which is easily accumulated on the top surface of an insulating member 15 is released, thereby preventing the reverse surface of the transfer material 13 from being stained with suspended toner which sticks on the reverse surface by being attracted when charges are accumulated on the top surface of the insulating member 15 or adverse influence of the sticking toner from being exerted upon transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a corona transfer device such as an electrophotographic copying machine.

BACKGROUND ART In recent years, in electrophotographic copying machines and the like, corona transfer devices are most commonly used, which develop toner images on an image bearing member such as a photoreceptor and transfer the toner images onto a transfer material using a transfer charger. It is used.

An example of the conventional corona transfer device mentioned above will be described below with reference to the drawings.

FIG. 2 shows a conventional corona transfer device. Second
In the figure, a toner image 2 developed on an image carrier 1 such as a photosensitive drum is placed on a transfer material (paper) 3 that has been fed along a transfer material guide and a guide plate 4, and is placed on a shield 5 and a discharge material. The image is transferred by a transfer charger 7 made of a wire 6.

Problems to be Solved by the Invention However, with the above configuration, the toner image on the image carrier 1 is sometimes dispersed on the transfer material 3 during transfer, resulting in a decrease in image quality. For example, the original characters shown in FIG. 3A deteriorate due to transcription as shown in FIG. 3S.

The above cause is due to insufficient contact width between the transfer material and the image carrier (along the direction in which the transfer material travels). That is, in FIG. 2, since the transfer material is not yet in sufficient contact with the image carrier and receives corona discharge, the toner scatters during the transfer, and as a result, the toner is scattered around the characters as shown in FIG. 3. smearing occurred, and in the case of fine letters, the lines themselves sometimes disappeared.

In order to prevent the spread of such corona, there is an attempt to narrow the opening of the transfer charger to limit the opening on the transfer material entrance side, as shown in Figure 4, but in this case, toner scattering during transfer is prevented. Although it can be prevented, the corona current flowing through the shield increases, which reduces the transfer efficiency, and the electrostatic attraction between the transfer material and the image carrier becomes insufficient, resulting in subtle misalignment between the transfer material and the image carrier, so-called jitter. is likely to occur. Furthermore, since the opening is narrow, it is difficult to clean the transfer charger when it becomes dirty.

In view of the above problems, the present invention provides a corona transfer device that has high image quality and is easy to maintain.

Means for Solving the Problems In order to solve the above problems, the corona transfer device of the present invention has a corona discharge wire, a back conductive member, and an insulating member provided on both sides sandwiching the corona discharge wire. A transfer material guide plate, which is made of a conductive member on the image carrier side and an insulating member on the transfer charger side, is arranged between the charger and the image carrier so as to cover the transfer material entrance side opening of the transfer charger. This is what I did.

Effect of the Invention With the above-described configuration, the present invention allows the corona discharge from the corona discharge wire to strongly converge on the area where the image carrier and the transfer material are in close contact with each other, thereby producing high-quality images with less toner scattering, good transfer efficiency, and less jitter. In addition, cleaning is easy and maintainability is high.

EXAMPLE Hereinafter, a corona transfer device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a corona transfer device in an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes an image carrier such as a photosensitive drum, which rotates in the direction of the arrow, and the toner image 12 developed on the image carrier reaches a transfer position. 13 is a transfer material such as paper.

The corona transfer device includes a corona discharge wire 16, a shield case 1γ made of a conductive member such as a metal surrounding it, and insulating members 18 and 19 such as a polyester film attached to the inner surfaces of both side walls of the shield case 17. The transfer material guide 102 is composed of a transfer charger 101, a conductive member 14 made of metal or the like on the image carrier side, and an insulating member 15 such as IJ ester film on the transfer charger side. The tip of the transfer material guide 102 is disposed at an appropriate spatial position between the inner wall of the insulating member 18 on the transfer material entrance side of the transfer charger 101 and directly above the corona discharge wire 16. Furthermore, the height of the insulating members 18 and 19 on the inner wall of the transfer charger 101 is higher than each side wall of the shield case 1, and the insulating member 16 of the transfer material guide 102 is made to protrude slightly more than the conductive member 14.

The operation of the corona transfer device configured as described above will be explained using FIG. 1.

The state of corona discharge when transfer rolling pressure is applied to the corona discharge wire 16 from a high voltage power source is schematically shown by electric lines of force 20 and 21. Transfer charger 101 is shield case 1
Since insulating members 18 and 19 are provided on the inner surfaces of both side walls of 7, corona discharge flows 2o toward the transfer material 13 and 21 flows toward the bottom of the shield case 17, which acts as a back electrode.
The flow is divided into two, so that it does not flow wastefully to the sides. Furthermore, since the insulating member 15 of the transfer material guide 102 covers the transfer material entrance side opening of the transfer charger 1o2, a corona discharge current strongly directed toward the area in close contact with the transfer material 13 can be efficiently obtained.

Further, due to the presence of the conductive member 14 of the transfer material guide 102, charges that tend to accumulate on the upper surface of the insulating member 16 are released, and when charges are accumulated on the upper surface of the insulating member 16, floating toner is adsorbed, and this toner is It is possible to effectively prevent the inconvenience of toner adhering to the back surface of the transfer material 13 and causing backside stains, or the adverse effects of the adhering toner on the transfer.

As described above, according to this embodiment, since the corona discharge acts strongly and effectively on the area where the image carrier and the transfer material are in close contact with each other, a high-quality image with less toner scattering, good transfer efficiency, and less jitter can be obtained. . Furthermore, since the transfer charger does not have a restricted opening, it is easy to clean when it becomes dirty.

Effects of the Invention As described above, the present invention provides an image carrier between an image carrier and a transfer charger having a corona discharge wire, a rear conductive member, and insulating members provided on both sides sandwiching the corona discharge wire. By arranging the transfer material guide plate, which is made of a conductive material on the body side and an insulating material on the transfer charger side, so as to cover the transfer material entrance side of the transfer charger, toner scattering is reduced.
High-quality images with high transfer efficiency and low jitter can be obtained.
It is possible to provide a corona transfer device that is easy to maintain.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a corona transfer device according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional example, and FIG. 3 is a diagram showing original characters to be copied and examples of characters deteriorated by transfer. FIG. 4 is a block diagram of another conventional example. 11... Image carrier, 12... Toner image, 13... Transfer material, 101... Transfer charger, 102... Transfer Material guide plate. //--Ittoyo ni Tenko-sai/2---)Na4L/, 3--Ichitenkinkoto/4-+tIa? F'JA Figure 1 /6. Iβt/q-extinction/pressure member/6-
--Jin J mo Wire/7--- Seal F Kejin 101--1 Matsu copying song mo number 102 -1-! ff,, give it Kfl"4 de L12
Figure 3

Claims (1)

[Claims] A transfer charger including a corona discharge wire, a back conductive member provided on the back surface of the corona discharge wire, and insulating members provided on both sides sandwiching the corona discharge wire, and an image carrier on which a toner image is formed. A transfer material guide plate is disposed between the image carrier and the transfer material guide plate, the transfer material guide plate being made of a conductive member on the image carrier side and an insulating material on the transfer charger side, so as to cover the transfer material entrance side opening of the transfer charger. Device.