JPH04124690A - Cleaning device - Google Patents

Abstract

PURPOSE:To prolong the life of a cleaning blade by providing a power source device which can vary an impressed voltage in a direction where the force of attracting toner from a photosensitive body to a cleaning brush is strengthened or can change the polarity of the impressed voltage in accordance with the increase of the number of passing papers. CONSTITUTION:The power source device 12 is controlled so that the impressed voltage is set to be low when the device is new and the impressed voltage is set to become higher as the number of passing papers is increased. Namely, corotron irradiation is performed to the photosensitive body 1 and the toner by a precleaning destaticizer/electrostatic charger 7 so as to set the potential of the photosensitive body at about -100 to -200V. Meanwhile, the impressed voltage on the cleaning brush 10 is set at about +100V at an initial time, and the toner is attracted when a potential difference is about 200 to 300V. As the device goes on being used, the number of passing papers is increased, so that the impressed voltage on the cleaning brush 10 is made higher in accordance with the number of passing papers, and the above potential difference is made larger.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention removes toner remaining on the surface of a photoreceptor after transfer using a cleaning brush to which a voltage is applied and a cleaning brush installed downstream of the cleaning brush in the direction in which the photoreceptor moves. The present invention relates to a cleaning device that cleans as a blade.

lNext summer! The cleaning device of the above type is well known and is included in copying machines, printers, facsimile machines, etc. that use an electrophotographic process. This type of cleaning device fl uses a blade cleaning method that scrapes off residual toner by bringing a cleaning blade into pressure contact with the photoreceptor, and a blade cleaning method that scrapes off the remaining toner by bringing a cleaning blade into pressure contact with the photoreceptor. This is a combination of two methods: a brush cleaning method that electrically removes residual toner from the photoconductor by rotating it; the cleaning brush performs most of the cleaning, and then the cleaning blade performs complete cleaning. known to obtain.

In the cleaning device configured as described above, the cleaning blade is always kept in pressure contact with the surface of the photoreceptor during the process of forming an image. For this reason, the edge of the cleaning blade gradually wears out due to friction with the surface of the photoreceptor, but this wear accelerates as the amount of manual toner power applied to the cleaning blade increases. However, if the amount of toner applied to the cleaning blade is small, components such as talc in the transfer paper and fine particles of additives such as silica will enter the edge of the cleaning blade, and the fine particles will be coated onto the photoreceptor. This disturbs the electrostatic latent image.

Problems to be Solved by the Invention As mentioned above, there are problems if the amount of toner input to the cleaning blade is too large or too small, but conventionally, the amount of toner input to the cleaning blade is reduced when it is large, and when it is small, it is reduced. It was difficult to make more.

For this reason, over time, as the cleaning brush is used, the cleaning power decreases due to toner sticking or falling, and therefore, a large amount of manual force is applied to the cleaning blade, which accelerates the wear of the cleaning blade.
The lifespan of the cleaning equipment was relatively short.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a cleaning device that can reduce the amount of human effort required to apply toner to a cleaning blade.

Means to resolve issues The structure of the present invention that achieves the above object is as follows.

(1) A cleaning brush to which a voltage is applied and the cleaning device remove toner remaining on the surface of the photoconductor after transfer;
In a cleaning device that cleans with a cleaning blade provided downstream in the direction of photoreceptor movement, a voltage is applied to the cleaning brush, and the magnitude of the applied voltage and the polarity of the applied voltage can be changed. What is claimed is: 1. A cleaning device comprising: a voltage device; the power source device varies the applied voltage or changes the polarity of the applied voltage in a direction that strengthens the toner adsorption force from the photoreceptor to the cleaning brush according to the number of sheets passed;

(2) A cleaning device that cleans toner remaining on the surface of the photoreceptor after transfer using a cleaning brush to which a voltage is applied and a cleaning blade provided downstream of the cleaning brush in the direction of movement of the photoreceptor,
A voltage device is provided that applies a voltage to the cleaning brush and can change the magnitude of the applied voltage and the polarity of the applied voltage, and the power supply device is configured to be able to detect light at the beginning or end of the cleaning operation compared to during the cleaning operation. A cleaning device characterized in that the applied voltage is varied or the polarity of the applied voltage is changed in the direction of increasing the toner adsorption force from the body to the cleaning brush.

(3) A cleaning device that cleans toner remaining on the surface of the photoconductor after transfer using a cleaning brush to which a voltage is applied and a cleaning blade installed downstream of the cleaning brush in the direction of photoconductor movement. In,
A voltage is applied to the cleaning brush, and a voltage device that can change the magnitude of the applied voltage and the polarity of the applied voltage is opened, and the power source device is activated when cleaning an area outside the image area or an area with a small image area. A cleaning device characterized by varying the applied voltage or changing the polarity of the applied voltage in the direction of increasing the toner adsorption force to the brush.

According to the configuration of claim 1, the cleaning power of the cleaning brush decreases due to toner sticking or falling due to use over time, and a large amount of manual force is applied to the cleaning blade, which accelerates the wear of the cleaning blade. However, by increasing the toner adsorption force to the cleaning brush depending on the number of sheets passed, the amount of manual force applied to the cleaning blade can be stabilized at an appropriate level, and the life of the cleaning blade can be extended.

According to the second aspect of the present invention, by weakening the toner adsorption force of the cleaning brush at the start or end of the cleaning operation, toner is supplied to the cleaning blade edge to some extent and fine particles are prevented from entering the edge portion.

According to the structure of claim 3, when the image area is small, such as outside the image area or small size, by weakening the toner adsorption force of the cleaning brush, a certain amount of toner is supplied to the cleaning blade edge, and the toner is transferred to the edge part of the fine particles. are prevented from entering.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic explanatory diagram of an electrophotographic process to which the cleaning device of the present invention is applied. The photoreceptor 1 rotates in the direction of the arrow, and is uniformly charged with positive or negative charges by the charger 2 during the rotation. Next, the reflected light 4 from the image exposure indicated by the arrow 3 passes through the mirror onto the photoreceptor 1, and an electrostatic latent image inverse to the original corresponding to the image density is formed on the surface of the photoreceptor.

Next, the developing device 4 attaches toner to the electrostatic latent image on the photoreceptor to form a visible image. The transfer paper 5 conveyed from a paper feed section (not shown) is sent out to the transfer/separation charger 6 in synchronization with the visible image on the photoreceptor. Then, under the action of the transfer/separation charger 6, the visible image on the photoreceptor is transferred to a transfer paper, and when separated from the photoreceptor 1, it is sent to a fixing section 9 (not shown).

On the other hand, the photoreceptor is cleaned and removed after the visible image is transferred to the transfer paper by the transfer/separation charger 6, and after the charge is uniformly removed by the charger 7, residual toner on the photoreceptor 1 is cleaned. .

Next, the residual potential on the photoreceptor is made zero by the static eliminator 9, and the photoreceptor is prepared for the next image formation.

As shown in FIGS. 1 and 2, the cleaning device 8 includes a cleaning brush 10 that comes into sliding contact with the photoreceptor 1;
A cleaning means is provided with a cleaning blade 11 which is disposed downstream of the cleaning brush 1o in the photoconductor movement direction and comes into pressure contact with the photoconductor 1. A power supply device 1 applies a bias voltage to the cleaning brush 1o.
2 is connected, and the recovery o is on the almost opposite side of the photoreceptor].
- The rubber 13 is in sliding contact. Note that reference numeral 14 is a blade that scrapes off toner adhering to the collection roller 13, and reference numeral 15 is a screw that transports the toner collected by cleaning to the outside of the cleaning device 8.

The cleaning device 8 having the above configuration performs cleaning/deletion/
The residual toner is uniformly charged by the charger 7, and a bias voltage having a polarity opposite to that of the toner is applied to the cleaning brush 10 by the power supply device 12, so that the residual toner is electrically attracted. Then, the toner wiped off by the cleaning brush 10 is attached to the collection roller 13, and then the blade]4
Scrape it off. In addition, residual I/ner that could not be cleaned with the cleaning brush 10 is removed using the cleaning blade 11.
scraped by.

The power supply device 12 is a variable IT source, and a preferred variable system will be described below.

As the cleaning brush 10 is used over time, its cleaning performance gradually decreases due to toner sticking, bristles falling down, and the like. If the cleaning performance of the cleaning brush 10 deteriorates, the amount of toner applied to the cleaning blade 11 will increase, the wear of the cleaning blade 11 will be accelerated, and the life of the cleaning device 8 will be shortened.

Therefore, the present invention controls the power supply device 12 so that the applied voltage is set low when the power supply device 12 is new, and the applied voltage is set to be increased as the number of sheets passed increases. To explain this specifically, the cleaning/charging device 7 irradiates the photoreceptor 1 and the toner with a corotron, and
The potential of the photoconductor is set at around 00V. On the other hand, the voltage applied to the cleaning brush 10 is initially set to about +100 V, as shown by the solid line in the graph of FIG.
Toner is adsorbed with a potential difference of about 200V to 300V. As use progresses, the number of sheets passing through increases, and the voltage applied to the cleaning brush 10 is increased according to the number of sheets passing through.
The above potential difference is increased.

The cleaning device 8 configured in this manner sets the initial potential difference with the photoconductor to be lower than that of the conventional example shown by the dotted line in FIG.
As the brush cleaning/cleaning performance decreases, the voltage applied to the cleaning brushes 10 is increased to compensate for the decrease in brush cleaning performance.

On the other hand, as shown by the dotted line in FIG. 3, a constant voltage is applied to the cleaning brush 10.

In the conventional example, the potential difference between the cleaning brush 0 and the photoreceptor 1 is large at the beginning, toner tends to stick to the cleaning brush 0, and the cleaning performance of the cleaning brush quickly deteriorates, causing the amount of toner to be applied to the cleaning blade 11 to be reduced. will also gradually increase. Therefore, as is clear from the graph of FIG. 4, the present invention greatly improves the cleaning performance of the cleaning device compared to the conventional example.

Next, if the amount of toner applied to the edge of the cleaning blade 11 is small as shown in FIG. Problems such as disturbing the environment may occur. This problem is caused by cleaning blade]
] If you input a certain amount of toner in advance, the sixth
As shown in Figure (a), the toner T can reduce the input of fine particles S into the edges.

Therefore, the amount of human power applied to the cleaning blade 11 can be controlled using the variable power supply device 12. 1st
As shown in the graph of Fig. 5, the areas corresponding to the leading and trailing edges of the image on the photoreceptor are exposed to the cleaning brush 1.
When it touches 0, the applied voltage is lowered, and during the intermediate cleaning operation, the applied voltage is controlled to be increased to a predetermined value.

With this configuration, fine particles can be removed from the cleaning blade 1.
1, the cleaning performance of the cleaning brush 10 is weakened to allow toner to be input, thereby reducing the possibility of fine particles entering the edge of the cleaning blade 11.

Further, the amount of manual effort applied to the cleaning blade 11 to toner may be significantly reduced when an image with a small paper spacing and area is copied during continuous copying. At this time as well, the voltage applied to the cleaning brush 10 is set low as shown by the chain line in FIG.
・Forcibly attach the glue.

With this configuration, the toner forcibly adhered to the photoreceptor l can be input to the cleaning blade 11 by weakening the toner adsorption force of the cleaning brush 10, and problems caused by fine particles can be alleviated. Note that a method for forcibly adhering some toner to the photoreceptor 1 can be carried out by weakening the developing bias 16 shown in FIG. 1 or by weakening the erasing force of an eraser (not shown).

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways.

For example, in the above embodiment, when the toner adsorption force to the cleaning brush is weakened, the variable applied voltage is set low by a variable power supply device, but the applied voltage is set to the same polarity as the toner, and the toner adsorption force to the cleaning brush is set low. A power supply device that can change the polarity of the applied voltage when increasing the force or returning it to normal may be used.

Further, in the above embodiment, the toner is kept at a constant potential using a cleaning remover/charger, but if the toner polarity is constant without using a cleaning remover/charger, the voltage applied to the cleaning brush can be changed. The same effect can be obtained.

Furthermore, the power supply device can also be used as a bias power supply for the collecting roller. In this case, by varying the voltage of the power supply device, the potential of the cleaning brush can be changed via the collection roller, and the same effect as in the above embodiment can be obtained.

Effects According to the above configuration, the cleaning brush of the present invention decreases its cleaning power due to toner sticking and falling due to use over time, and the amount of human power applied to the cleaning blade is large, which accelerates the wear of the cleaning blade. However, by increasing the toner adsorption power to the cleaning brush depending on the number of sheets passed, the amount of manual force applied to the cleaning blade can be stabilized at an appropriate amount, and the life of the cleaning blade can be extended.

In addition, by weakening the toner adsorption force of the cleaning brush at the beginning or end of the cleaning operation, toner was supplied to a certain extent to the edge of the cleaning blade, and it was possible to prevent fine particles from entering the edge portion.

Furthermore, when the image area is small, such as outside the image area or small size, by weakening the toner adsorption force of the cleaning brush, a certain amount of toner is supplied to the cleaning blade edge, and it is possible to prevent fine particles from entering the edge part. did it.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an electrophotographic process to which the cleaning device of the present invention is applied, FIG. 2 is an enlarged diagram of the cleaning device, and FIG. FIG. 4 is a graph showing the relationship between the cleaning performance and the number of sheets passed between the present invention and the conventional example. FIG. 5 is a timing chart showing the relationship between the image position and the amount of human effort applied to the cleaning blade. Figure 6(a),
(b) is an enlarged explanatory diagram showing the input state of toner and fine particles to the cleaning blade edge. 1...Photoreceptor 8...Cleaning device 10...Cleaning brush 11...Cleaning blade 12...Power supply device k Fig. 3 Toshito Tamakihanfu

Claims (3)

[Claims] (1) A cleaning device that cleans toner remaining on the surface of a photoreceptor after transfer using a cleaning brush to which a voltage is applied and a cleaning plate provided downstream of the cleaning brush in the direction of movement of the photoreceptor, A voltage device is provided that applies a voltage to the cleaning brush and can change the magnitude and polarity of the applied voltage, and the power supply device transfers toner from the photoreceptor to the cleaning brush according to the number of sheets passed. A cleaning device characterized in that the applied voltage is varied or the polarity of the applied voltage is changed in the direction of increasing the attraction force. (2) In the cleaning device, the toner remaining on the surface of the photoreceptor after transfer is cleaned by a cleaning brush to which a voltage is applied and a cleaning plate provided downstream of the cleaning brush in the direction of movement of the photoreceptor, as described above. A voltage device is provided that applies voltage to the cleaning brush and can change the magnitude of the applied voltage and the polarity of the applied voltage. A cleaning device characterized in that the applied voltage is varied or the polarity of the applied voltage is changed in the direction of increasing the toner adsorption force to the cleaning brush. (3) In the cleaning device, the toner remaining on the surface of the photoconductor after transfer is cleaned by a cleaning brush to which a voltage is applied and a cleaning blade provided downstream of the cleaning brush in the direction in which the photoconductor moves. A voltage device that applies voltage to the cleaning brush and can change the magnitude and polarity of the applied voltage is provided, and the power source device removes the power from the photoreceptor when cleaning outside the image area or in an area with a small image area. A cleaning device characterized in that the applied voltage is varied or the polarity of the applied voltage is changed in the direction of increasing the toner adsorption force to the cleaning brush.