JPS5842067A - Charging device for copying mahcine - Google Patents

Abstract

PURPOSE:To prevent the dirt of the rear face of a transfer paper due to the toner dirt of a brush and to prevent the lowering of the capcity of the bursh, by inverting the voltage applied to the brush when the brush passes a non- picture area on a photoreceptor and sticking the toner, which is stuck to the brush once, to the photoreceptor again. CONSTITUTION:In the transfer process, the voltage having a polarity opposite to that of a toner 4 on a photoreceptor 1 is applied to a brush 2 and is slided on a rear face 5a of a transfer paper 5 to transfer the toner 4 to a front face 5b of the transfer paper 5 by attraction. Through the toner 4 is stuck to the brush to make the brush dirty if the brush 2 is pressed to the surface of the photoreceptor 1 when the transfer paper 5 does not exist, the voltage having a polarity opposite to that required for transfer is applied to the brush to stick the toner 4, which is stuck to the brush 2, to a surface 1a of the photoreceptor again when the brush 2 is pressed to an inter-image part which is a non-picture area between copy operations, and thus, the brush 2 is not dirty with the toner adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brush charging device for a copying machine in which a brush charger is provided facing a photoreceptor.
There is dirt due to adhesion of scattered toner inside the copying machine, or dirt due to direct contact between the brush and the developing toner in the non-image area (interimage) of the photoreceptor when used in the transfer process.

Contamination caused by the first cause can be countered by air 7u or by scattered toner.

Furthermore, in order to avoid contamination caused by the second cause, it is conceivable to press the brush against the photoreceptor only when the transfer paper passes through.
In this case, the structure becomes complicated, and contact between the photoreceptor and the brush depending on the copy size is practically unavoidable, leading to contamination on the same surface of different sizes. In addition, it is practically difficult and impossible to change the brush pressure timing (time) for each size of transfer paper.As a result, toner may adhere to the brush, causing deterioration of its performance as a brush. At the same time, the toner adhering to the brush during transfer comes into sliding contact with the back surface of the transfer paper, staining the back surface of the transfer paper.

The present invention was made in view of the above circumstances, and its purpose is to re-adhere the toner that has adhered to the brush to the photoreceptor, thereby eliminating stains on the transfer paper, the back side of the brush, and the like due to toner stains on the brush. The purpose is to prevent performance degradation and provide a complete brush charging device for Kuman photo machines.

Figure 1 shows the entire structure when used in the transfer process, in which a brush 2 is provided facing the photoreceptor 1, and the brush 2 is connected to a power source 3. The brush 2 is in pressure contact with the surface 1a, and a voltage of opposite polarity to the toner 4 on the photoreceptor 1 is applied to the m1fr5a of the transfer paper 5. 0 Therefore, if the VCC brush suddenly comes into pressure contact with the photoreceptor surface 1 when there is no transfer paper 5, the toner 4 will adhere to the brush 2& and the brush 2 will become dirty, and the second crease C will appear. The width of the transfer paper 5 that extends in the width direction of the photoconductor 1 is 1N,
When the brush 2 comes into contact with both side portions 5i1'-1' of the brush 2, the toner in the portions 1'-1' will adhere to the brush 2. (That is, it adheres due to the applied voltage of the brush 2 and the mechanical contact LC).

On the other hand, instead of using the entire area of the photoreceptor 1 for the copy operation VC, there is a portion between the copy operations that is not used for the copy operation (an interimage portion that is a non-image area).

Therefore, as shown in FIG. 3, the polarity of the brush applying power source 3 was reversed.

In other words, a voltage of the polarity (electrode) necessary for transfer is applied from the copy front end t to the copy rear end t, and the voltage of the polarity (electrode) necessary for transfer is applied from the copy rear end t to the copy rear end t.
The polarity is reversed (-polarity) until the next copy tip t.
and apply it. In other words, when pressing the interimage portion, a voltage with a polarity opposite to that required for transfer is applied.

By doing this, 4t of toner attached to the brush 2 can be removed.
i The photoconductor surface 1aK is reattached to the brush 2 line toner-free state, which prevents staining on the back side of the transfer paper and deterioration of brush performance. Toner adheres to the brush 2 due to toner scattering around the brush 2 or a small amount of toner remaining due to poor cleaning of the photoreceptor surface 1a.

In the case of 3D printing, if the brush applying electrode is reversed at the interimage part to make it have the opposite polarity, the toner adhering to the brush 2 can be reattached to the photoreceptor surface 1aK: at this time. Due to the reverse polarity VC\i electric current, the reverse polarity toner in the developer is developed on the photosensitive material, and it is possible to prevent the reverse polarity toner from adhering to a part of the copy. It may also be in the form of a two-tube roll of brushes as shown in JK.

In addition, as a means for reversing the polarity of the voltage applied to the brush, a conventionally known means is used to adjust the rotation timing C of the photoreceptor l.
It is only necessary to invert the intermediate image part depending on the process timing).

With the present invention as described above, the toner layered on the brush 2 is allowed to re-adhere to the non-image area of the photoreceptor 1, thereby preventing the brush 2 from becoming smudged or smudged due to toner adhesion.

Therefore, it is possible to prevent deterioration in the performance of the brush and stains on the back surface of the transfer paper.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is an explanatory diagram when used in the transfer process; TA2 is an explanatory diagram of defects;
Figure 3 is a table showing changes in applied voltage polarity, Figures 4 and 5.
The figure is an explanatory diagram when used in a charging process. 1 is a photoconductor, 2 is a brush, and 3 different power supplies. Applicant: Fuji Xerox Co., Ltd. Agent Patent Attorney: Masaaki Yonehara Patent Attorney: Tadashi Flood Figure 1 Figure 3 T1 Meeting 2 Meeting 3 Figure 4 Figure 5

Claims (1)

[Claims] Press the brush 2 onto the surface of the photoreceptor I;
- A nuclear photosensitive drum device characterized in that, in a charging device connected to a charger 3, the pressure applied by the brush is reversed when a non-image 11 on a photoreceptor passes through a target area.