JPS62983A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To reduce the scattering of suspended toner during cleaning operation by allowing the magnetic brush of a magnetic brush cleaning device serving as a developing device to move in the same direction with an image carrier in an area where it abuts on the image carrier. CONSTITUTION:Image formation is performed while a photosensitive drum 7 makes two turns. Namely, transfer operation (developing operation) is performed in the 1st turn and cleaning operation is carried out in the 2nd turn. The cleaning operation is performed by the magnetic brush unit 3 serving as both cleaning device and developing device; and the magnetic brush M is so formed as to move in the same direction with the photosensitive drum 7 and a toner scatter suppressing plate 32 for suppressing the scattering of suspended toner is provided at the downstream side of the brush. Consequently, the majority of residual toner separated from the photosensitive drum 7 is attached by the magnetic brush M to decrease the amount of suspended toner scattering on the upstream side of the magnetic brush unit 3 and also decrease that at the downstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic apparatus such as an electrophotographic copying machine. In particular, the present invention relates to an improvement in an electrophotographic apparatus having a magnetic brush cleaning device that removes residual toner and the like attached to an image carrier by rubbing it with a magnetic brush.

2. Description of the Related Art In an electrophotographic apparatus, such as an electrophotographic copying machine, having the above-described magnetic brush cleaning device, the magnetic brush of the magnetic brush cleaning device is configured to move in a direction opposite to the image carrier in a region where it comes into contact with the image carrier VC'. Conventionally, devices equipped with a magnetic brush cleaning device are generally known, but during cleaning operation, floating toner that is not attracted to the magnetic brush scatters outside the magnetic brush cleaning device, contaminates the peripheral equipment of the image carrier and causes problems in image formation. There is a problem that performance is degraded.

For example, the electrophotographic copying machine shown in FIG. 2 is configured such that the magnetic brush M moves in the opposite direction to the photosensitive drum 7 as shown by an arrow in the area where it comes into contact with the photosensitive drum 7, which is an image carrier. The magnetic brush unit 3 also serves as a magnetic brush cleaning device and a developing device, and the photosensitive drum 7 serves as a magnetic brush cleaning device and a developing device.
The image forming apparatus is configured to carry out development and removal (17) while rotating to form one image. That is, in the electrophotographic copying machine, the magnetic brush unit 3 is connected to the photosensitive drum 0.
It functions as a developing device in the first rotation and as a cleaning device in the second rotation, enabling clear development and cleaning without damaging the photosensitive drum 7. However, during the developing operation, toner is scattered outside the magnetic brush unit 3 during the cleaning operation, and the toner is scattered outside the charger 1. Exposure device 2. There is a problem in that peripheral devices of the photosensitive drum 7, such as the transfer device 4, are contaminated. In particular, the exposure device 2 disposed upstream of the magnetic brush unit 3 is heavily contaminated, resulting in insufficient exposure and a significant drop in image forming performance.

As described above, electrophotographic apparatuses having conventional magnetic brush cleaning devices are not sufficient for practical use because the peripheral equipment of the image bearing member is contaminated during the cleaning operation and the image forming performance is degraded. It's difficult.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems, and to reduce floating toner that scatters outside the magnetic brush cleaning device during the cleaning operation, and to reduce the amount of floating toner scattered outside the magnetic brush cleaning device and the peripheral equipment of the image carrier, IvfVc1! It is an object of the present invention to provide an electrophotographic apparatus which can prevent deterioration of image forming performance by using a contamination device of an optical device t.

Structure of the Invention As a result of research to achieve the above object, the present inventor has discovered that by moving the magnetic brush of the magnetic brush cleaning device in the same direction as the image carrier in the area where it comes into contact with the image carrier, it is possible to achieve a cleaning method similar to the conventional one. It has been found that the scattering of floating toner can be greatly reduced compared to the case of moving in the opposite direction, and it is possible to prevent contamination of peripheral equipment of the image bearing member.

The present invention has been completed based on the above findings, and provides an electrophotographic apparatus including a magnetic brush cleaning device in which the magnetic brush is placed facing the image carrier so that the magnetic brush contacts the image carrier. The above object has been achieved by constructing an electrophotographic apparatus characterized in that it has a magnetic brush cleaning device configured to move in the same direction as the image carrier in the area of contact.

Example The present invention will be explained in detail by way of examples.

FIG. 1 is a schematic explanatory diagram of an electrophotographic copying machine for explaining the present invention in detail.

The electrophotographic copying machine shown in FIG.
．． Magnetic brush unit 3. Transfer device 4I separator 5. Fuser 6I photoreceptor drum? , a paper feed roller 8, an AC bias power supply V, etc., the magnetic brush unit 3 serves both as a magnetic brush cleaning device and a magnetic brush forming means of the developing device, and the photosensitive drum 7 is It is operated so as to form one image during two rotations. As mentioned above, the magnetic brush unit 3 serves as a magnetic brush forming means for both the magnetic brush cleaning device and the developing device, and
The magnetic brush M formed at 1 functions as a developing device during a copying operation, and can function as a cleaning device when an AC bias is applied during a copying operation. Further, the magnetic brush M is formed to move in the same direction as the photosensitive drum 7, as shown by the arrow. Reference numeral 32 denotes a toner scattering prevention plate, which is disposed downstream of the magnetic brush unit 3 to prevent floating toner from scattering.

The electrophotographic copying machine shown in FIG. 1 is constructed as described above, and one image is formed during two rotations of the photoreceptor drum. During the first rotation, a copying operation, that is, a developing operation is performed. Then, a cleaning operation is performed in the second rotation. That is, in the 01st rotation of the photoreceptor, charging is performed by the charger 1, exposure is performed by the exposure device 2, AC bias is applied, and development is performed by the magnetic brush unit 3 which functions as a developing device.

Processes such as transfer to the transfer paper P by the transfer device 4, separation of the transfer paper P from the photoreceptor drum 7 by the separator 5, etc. are sequentially performed to form an image. The transfer paper P separated by the separator 5 is sent to the fixing device 6 and subjected to a fixing process. On the other hand, the photosensitive drum 7 completes its first rotation with untransferred toner (residual toner) attached thereto. When the photosensitive drum 7 starts its second rotation, the charger 1 is set to a non-operating state, and an AC bias is applied to the magnetic brush unit 3. When the photosensitive drum 7 rotates, residual toner is rubbed by the magnetic brush M of the magnetic brush unit 3, which acts as a magnetic brush cleaning device. When the toner is rubbed by the magnetic brush, the residual toner is attracted by the magnetic brush M and removed from the photosensitive drum 7. After the photosensitive drum 7 is cleaned by the magnetic brush M as described above, it completes its second rotation. Then, it waits at the copying start position, and thereafter the developing operation and cleaning operation are performed in the same manner. During cleaning operation,
The residual toner adhering to the photoreceptor drum 7 is removed by a magnetic brush M.
Although the toner is rubbed and peeled off from the photoreceptor drum 7, most of it is attracted by the magnetic brush y, and the amount of floating toner that is scattered outside is far less than in the past. In particular, the amount of floating toner scattered upstream of the magnetic brush unit 3 is extremely small, and the exposure device 2. Contamination of charger 1, etc. was significantly reduced. Moreover, on the downstream side of the magnetic brush unit 3,
Since the floating toner scattering prevention plate 32 is provided, the amount of floating toner that scatters is also significantly reduced. In addition,
During the developing operation, the magnetic brush M performs a developing action as a magnetic brush of the developing device, but at this time, toner with a small amount of charge does not adhere to the photoreceptor drum 7, becomes floating toner, and is scattered outside the magnetic brush unit 3. do. The floating toner scatters in large quantities on both the upstream and downstream sides of the magnetic brush unit 3, but the amount is significantly less than during the cleaning operation, and a floating toner scattering prevention plate 32 is disposed on the downstream side. Therefore, scattering to the outside is sufficiently suppressed. As described above, in this embodiment, the floating toner magnetic brush unit 3
The scattering from the photoreceptor drum 70 peripheral equipment, especially the magnetic brush unit 3. is significantly reduced compared to the conventional one.
Contamination of the charger 1, etc. of the exposure apparatus 2, which is disposed upstream of the exposure apparatus 2, has been significantly reduced.

Note that in this embodiment, the photosensitive drum 7 is
It is preferable that the magnetic brush M is configured to be moved at a linear velocity of 1 to 10 times that of the magnetic brush M.

Furthermore, in this embodiment, the magnetic brush cleaning device and the developing device share the same magnetic brush forming means, but they may be provided separately.

Although it is preferable to apply an AC bias to the magnetic brush unit as a magnetic brush cleaning device, other oscillating bias voltages such as a pulsed DC bias may be applied, and of course, any oscillating bias voltage may be applied. It may be something you don't do. In this embodiment, a drum-shaped image carrier is used, but it goes without saying that a belt-shaped one may also be used.

Effects of the Invention As explained in the embodiments, the electrophotographic apparatus of the present invention is capable of moving in the same direction as the image carrier in the area where the magnetic brush of the magnetic brush cleaning device contacts the image carrier. Compared to conventional systems, contamination of peripheral equipment of the image carrier, particularly equipment disposed upstream of the magnetic brush cleaning device, is significantly reduced, and deterioration of image forming performance can be significantly prevented. Further, by disposing a toner scattering prevention plate on the downstream side of the magnetic brush cleaning device as shown in the embodiment, it is possible to prevent contamination of the peripheral equipment disposed on the downstream side.

As described above, the present invention was able to achieve the above object with the above configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic illustration of an embodiment of the present invention, and FIG. 2 is a schematic illustration of a conventional example. 3...Magnetic brush unit. 31... Magnetic roll + 32... Toner scattering prevention plate. 7...Photosensitive drum, M...Magnetic brush t'■
...AC bias power supply. Patent applicant: Konishiroku Photo Industry Co., Ltd. Figure 1 Figure a

Claims (3)

[Claims] (1) In an electrophotographic apparatus having a magnetic brush cleaning device disposed facing the magnetic brush so that the magnetic brush contacts the image carrier, the magnetic brush moves in the same direction as the image carrier in the area where the magnetic brush contacts the image carrier. An electrophotographic apparatus comprising a magnetic brush cleaning device configured as follows. (2) The electrophotographic apparatus according to claim 1, wherein the magnetic brush cleaning device is configured to also serve as a developing device. (3) The magnetic brush of the magnetic brush cleaning device is configured to move at a linear velocity of 1 to 10 times the linear velocity of the image carrier.
The electrophotographic device described in Section 1.