JPH0378782A - Cleaning device - Google Patents

Abstract

PURPOSE:To remove foreign matters stuck to the surface of a photosensitive body without damaging the surface thereof by forming the top of a brush bristle in the shape of a loop and separating a twisting part provided on a part where the twist of plural fibers forming one loop appears on a tighting side when the twist rubs the surface of the photosensitive body from an abutting position. CONSTITUTION:A rubbing member is composed of a brush roller 14, a large number of bristles of the brush roller 14 are made of plural fibers with the twisting part 20, and the loop 18 is provided on the top. The twisting part 20 is provided out of the abutting point where the surface of the photosensitive body 1 abuts on the rubbing memeber 14, and the twisting position appearing on the tight side when the member rubs the surface of the photosensitive body 1 is arranged aparted by the distance that the phososensitive body does not move to the abutting point at the time of rubbing away from the abutting point. The top of the loop 18 of bristles 17 formed with twisted fibers of the brush roller 14 is brought into contact with the surface of the photosensi tive body 1, and a large number of single fibers composing the twisted fibers sequential ly are brought linearly into contact with the surface of the photosensitive body 1 and polish the body. Thus, foreign matters stuck to the surface of the phososensitive body 1 can be removed without damaging the surface of the photosensitive body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device for a photoreceptor of an image forming apparatus using an electrophotographic process such as a copying machine, facsimile machine, or printer.

[Prior Art] A so-called electrophotographic image forming apparatus, for example, projects an optical image of a document onto the surface of a charged photoreceptor to form an electrostatic latent image on the photoreceptor, and then uses a developer to transfer the image onto the surface of the photoreceptor. In an image forming apparatus such as a copying machine, a transferable visible image is formed, the image is transferred onto the surface of a transfer material, the image is fixed on the transferred transfer material, and the copy is ejected outside the machine to obtain a copy. A cleaning means is required to remove residual toner remaining on the surface of the photoreceptor and use it repeatedly for image formation. As a cleaning means for this type of image forming apparatus, a cleaning blade made of an elastic material such as rubber is widely used because it has a simple structure and has excellent toner removal performance.

However, this cleaning blade does not remove solidified and fused toner, metal oxides such as silicon carbide and triiron tetroxide added to 1-Chi, and fine powders such as charge control agents.
If foreign matter such as fibrous paper dust, rosin, talc, etc. deposits generated from the transfer material or corona products generated by the charging device adhere to the surface of the photoreceptor, the performance is not necessarily sufficient to remove them. It could not be said that it had a

Contaminants adhering to the surface of the photoconductor may become low in resistance in high-temperature environments, deteriorating the electrostatic latent image on the photoconductor. In the forming apparatus, a problem has arisen in that after the toner passes through the cleaning blade, it is triboelectrically charged by the carrier in the developing device, and toner adheres to the toner, which adversely affects the visible image.

This is a more serious problem not only for Se photoreceptors that have been widely used in the past, but also for photoreceptors made of organic photoconductors such as OPC, and amorphous silicon photoreceptors, and is a serious problem for image forming apparatuses that use these photoreceptors. The cleaning device has
In addition to the removal of residual toner on the photoreceptor, the ability to remove contaminants adhering to the surface of the photoreceptor is also being questioned.

As a means to solve these problems, a device that combines a roller made of an elastic material such as silicone rubber and a rubber blade is proposed, for example, in Japanese Patent Laid-Open No. 60-10707.
This has already been proposed in Publication No. 6, etc. This method involves rubbing the photoreceptor with an elastic roller holding a thin layer of toner on the surface, thereby appropriately polishing the photoreceptor surface and scraping off contaminants adhering to the surface.

However, a drawback of this device is that it is difficult to form a uniform thin toner layer on the elastic roller, and if a toner layer with an uneven thickness is formed, it may cause uneven polishing of the photoreceptor. Streak scratches occurred on the surface, and these scratches were sometimes visible in the image transferred to the transfer material. Furthermore, if too little toner adheres to the elastic roller, excessive polishing may occur, significantly shortening the life of the photoreceptor. In image forming apparatuses that use non-magnetic toner, when the roller is stopped for a long period of time in a high-temperature environment, there is a problem that the toner solidifies and welds at the contact portion between the roller and the photoreceptor.

Another device that holds magnetic toner mixed with an abrasive material on the surface of a magnetic cleaning roller and rubs the photoreceptor is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-25678. Not only is it expensive, but there is also concern about the effect that the abrasive added to the toner will have on the image, and the toner used in image forming devices is limited to magnetic toner, so it is difficult to construct the device system. There was a problem that resulted in significant restrictions.

[Problem to be solved by the invention]

The present invention solves the above conventional problems and not only removes residual toner on the photoreceptor, but also removes contaminants adhering to the surface while preventing local damage and scratches on the photoreceptor surface. An object of the present invention is to provide a cleaning device that can maintain high-quality images over long periods of use, including changes in the environment.

[Means to solve the problem]

The present invention solves the above problem by having a rubbing member that rubs the surface of the photoreceptor after the toner image formed on the photoreceptor is transferred to recording paper, and cleaning the surface of the photoreceptor after the transfer. In the cleaning device for the image forming apparatus, the rubbing member is composed of a brush roller, the bristles of the brush roller are made of a plurality of fibers each having a twisted portion, and the tip of the brush roller has a loop. and a position away from the contact point between the sliding member and the sliding member, and a position away from the contact point by a distance such that the twisting position on the tight side when sliding against the photoreceptor surface does not move to the contact point during sliding rubbing. The problem was solved by a cleaning device characterized by being placed in the

[Effect]

According to the present invention, the loop-shaped tips of the bristles formed by the twisted fibers of the brush roller come into contact with the surface of the photoreceptor, and a large number of single fibers constituting the twisted fibers are sequentially applied to the surface of the photoreceptor. The polishing action is performed by making a line contact with the photoreceptor surface, and the line contact between the single fiber and the surface of the photoreceptor is made approximately as many times as the number of single fibers for each bristles. Line contact is made multiple times with the winter hairs, and since rubbing is performed while repeating line contact with each of the many hairs, an extremely uniform polishing effect is achieved, and foreign matter adhering to the surface of the photoreceptor is reliably removed. It no longer causes damage such as scratches.

The present invention has made it possible to remove foreign matter adhering to the surface of a photoreceptor using a rubbing member consisting of a brush roller, which was previously thought to be difficult.

When the loop-shaped tips of the hairs rub against the surface of the photoreceptor, the fibers that make up the hairs are twisted by the force applied from the outside. Due to the propagation of the twist during this rubbing, the already provided twisted part expands and moves, and the loose twisted part tends to move away from the contact point between the bristles and the photoreceptor surface, and the tight twisted part tends to approach the contact point. Therefore, if the twisted part on the tight side is close to the contact point, the twisted part will move to the contact point due to the twisting during rubbing and damage the surface of the photoreceptor. Since the position of the part is so far away that it cannot move to the contact point due to twisting during sliding, the influence of twisting during sliding can be avoided.

〔Example〕

Hereinafter, details of the present invention will be explained based on embodiments shown in the drawings.

FIG. 1 is a front sectional view schematically showing the vicinity of a photoreceptor of an image forming apparatus using an electrophotographic process including a cleaning device of the present invention. The surface of the photoreceptor drum 1 is first charged with a negative charge by the charger 2, and then an electrostatic latent image is formed by the reflected light of the original image reflected on the mirror 3, and then this electrostatic latent image is formed. The image is developed as a visible image by one of the two developing devices 4.5, which can take an active position or a non-active position at will according to the operator's will. Subsequently, the latent image charge is reduced by light emitted from above the visible image by the pre-transfer static elimination light source 6, thereby increasing the efficiency of transferring the toner image to the transfer material by the transfer corona 7.

A transfer material such as paper (not shown) is fed to the photosensitive drum 1 by the registration roller 12 in a timely manner, and after the toner image is transferred by the action of the transfer corona 7, the transfer material is transferred by the subsequent separation corona 8. Appropriate charge removal is performed and the film is peeled off from the surface of the photoreceptor. The separation claw 9 is used to assist in separating the transfer material.

After the toner image has been transferred, the photosensitive drum 1 is cleaned of toner residual images and other adhering foreign matter by the cleaning device 10 according to the present invention, and is then completely neutralized by light from the static eliminating light source 11 and is ready for reuse. Ru. The developing device uses a two-component developer consisting of carrier and toner, but is not limited to this.
Non-magnetic!・It is also possible to use a device made by Kner.

The cleaning device 10 includes a cleaning blade 13 and a brush roller 14 as members for rubbing against the surface of the photoreceptor.

As shown in FIG. 2, the brush roller 14 has a shaft-shaped core material 15 and a base fabric 16 of a constant width that is spirally wound around the core material 15, and the base fabric 16 has a large number of bristles. 17 was formed,
As shown in FIG. 3, the bristles 17 are made of twisted yarn formed in a pile shape on the base fabric 16, and have a loop 18 at the tip.
has.

Conventional brush rollers have their bristles cut off; for example, cut pile brushes are used, which have the ends of the pile cloth cut so that there are no loops.
The cut ends of the hair come into point contact with the surface of the photoconductor, and if a thick fiber is used, the edges of the cut surface of the cut ends of the hair will damage the surface of the photoconductor. Scraping marks (polishing marks) due to body surface polishing will occur in a streaky manner. If the fiber thickness is too thin to avoid damage, the fibers will escape and the desired rubbing or polishing action will not be obtained. It was thought that it could not be removed with a fibrous brush roller.

When the bristles of the brush roller 14 are formed into a loop shape as shown in FIG. 3, the tip loops 118 of the bristles arranged in large numbers rub against the surface of the photoreceptor drum 1 while repeatedly coming into line contact with the surface. This makes it possible to obtain extremely uniform polishing action, and by using fibers that are thicker than the fibers used in conventional cut-pile brushes, the photoreceptor drum I
Foreign matter adhering to the surface of the photoreceptor can be removed without causing damage such as scratches to the surface of the photoreceptor.

By appropriately selecting the yarn thickness, density, etc. of the fibers forming the loop, it can be used for photoconductors with low surface hardness, such as photoconductors based on semiconductors (so-called OPC photoconductors), and also for amorphous silicon photoconductors. It can also be effectively applied to photoreceptors with high surface hardness such as.

Since the brush roller 14 or cleaning blade 13, which is a rubbing member, has the ability to appropriately polish the surface of the photoreceptor, there is no need to add abrasives or the like to the developer unlike in the past, and these additives can improve the image quality. There is no risk of deterioration.

The fibers forming the bristles 17 of the brush roller 14 are made by twisting a large number of yarns into a single fiber bundle, but usually each fiber is twisted with a predetermined number of twists in the fiber spinning process, and is made into thin filaments. By adding twist to the bundle of yarn, the handling of the yarn when processing it into products is improved.

For products such as the base fabric that forms brush rollers, twisting is an important characteristic for maintaining brush bristles in a brushed state, which improves handling, and from the viewpoint of maintaining and managing the brushed state, a large number of twists is required. It is said to be very advantageous. However, when using a brush roller made of fibers with a large number of twists, the collective force of the multiple fibers of the thread that forms one loop increases,
It behaves as if it were a loop formed by a single thick thread. Therefore, the surface of the photoreceptor is scraped in thick stripes corresponding to the contact width of the loop tip. Therefore, the number of fiber twists is reduced within a range that does not impair workability and napping properties. In other words, as shown in FIG. 4, the interval between the twisted portions 20 of the hair 17, which is a yarn made by twisting a large number of filaments 19, is lengthened. Normally 25.4 mm (I i
When the number of twists per twist is reduced, the distance between the twist positions becomes longer than when there are many twists. When the tip of the fiber loop 18 with a small number of twists comes into contact with the surface of the photoreceptor, a large number of filammets (
The filaments (fibers) become unraveled, and the filaments, which are bundled to form one thread, are unraveled one by one and individually come into line contact with the surface of the photoreceptor. The contact points of the fibers with the photoreceptor surface are dispersed, the number of contact points increases, and the fiber contacts the photoreceptor over a wide area and performs a uniform rubbing action, and the rubbing action is concentrated locally as when there is a lot of twist. That is excluded. As a result, while using fibers that are thicker than the fibers used in conventional cut pile brushes, uniform rubbing and polishing can be performed without causing damage such as scratches to the photoreceptor surface, and the surface It is now possible to reliably remove attached foreign matter.

In order to ensure that the fibers forming the hair loop are separated in the range where they contact the photoreceptor, the twisting position of the fibers is outside the range where the fibers contact the surface of the photoreceptor. Set it as follows.

By preventing the twisted position of the fibers from coming into contact with the surface of the photoreceptor, the fibers can rub the photoreceptor in a reliably loosened state.

As illustrated in FIG.
In order to ensure that the fibers are in an unraveled state, it is convenient to position the twisted portions 20 of the fibers outside the contact range l.

Usually, the height of the loop of the bristles 17 is 2 to 10 mm in the case of a member for rubbing the surface of a photoreceptor in an electrophotographic process, and in most cases it is 2.5 to 6 mm.
The twisting position should be as far away from the contact range as possible in order for a bundle of multiple fibers with this loop height to come into contact with the photoreceptor drum and be loosened by rubbing. is preferred. In other words, it is preferable for the twisting position to be close to the root of the loop. From this, it is preferable that the fibers be twisted twice, once each at the base of the loop, or twisted at one of the bases. For this reason, it is preferable that the number of twists per loop be two or less.

Even if the fibers are in a static state and the contact range is between the two twisted portions, when the bundle of multiple fibers contacts the photoreceptor drum and rubs against it, as shown in Figure 5A, The external force P as a sliding force causes the fibers 19 to be twisted, with one twisted portion becoming a tighter side and the other twisted portion becoming a looser side. That is, 2
Looking at the influence of twisting by the external force P on the two twisted sections 20a and 20b, as shown in Figure 5B, the twisted section 20a on the left side of the figure tends to become tighter, while the other twisted section 20b tends to loosen. be. This causes the twisting action of the external force P to propagate or move the already formed twisted portion, or cause the twisted portion to expand.

In the example shown in FIG. 5, the position of the twisted portion gradually moves to the right in the figure. This indicates the same state as when the twisted portion on the tight side approaches the contact point between the bristles 17 and the surface of the photoreceptor where the external force P acts, and the twisted portion on the loose side separates.

Even if the twisted part is located at a position outside of the contact range l, if the position is not too far away, the twisted part on the tight side will move into the contact range due to the action of twisting that occurs during sliding. There is a possibility that

As shown in FIG. 6A, when the position of the twisting section 20 comes into contact with the surface of the photoreceptor drum 1, a large number of fibers become a bundle at the twisting position and become like one thick thread. The rubbing will be concentrated locally. The twisted part on the tight side is formed at a distance that does not affect the contact range even if the twist expands or propagates, and the twisted part on the loose side is formed at a position far from the contact range even if it is close. As shown in FIG. 8B, the twisting portion 20 can be reliably prevented from coming into contact with the photoreceptor drum, and the bristles of the brush can be prevented from coming into contact with the photoreceptor surface, as shown in FIG. 8B. The fibers become loose and dispersed, and the rubbing action by the brush roller becomes soft and uniform.

Since the hair fibers can come into contact with the photoconductor drum in a loose state, there is less risk of damaging the photoconductor surface by scratching it in streaks. It can be effectively used for photoreceptors with low surface hardness.

The light beam reflected and incident on the mirror 3 may be a beam light beam from a writing system such as a laser, and in this case, a so-called negative-positive development method, in which development is performed with toner having the same polarity as the latent image charge, is usually used. However, it goes without saying that the same effect will be achieved in that case as well.

〔effect〕

According to the present invention, by making the tips of the brush bristles into a loop shape, the brush roller shape can be created without damaging the surface of the photoconductor using relatively thick fibers, which was previously thought to be difficult. It became possible to polish and rub the surface of the photoreceptor evenly and appropriately using the rubbing member, and as a result, it became possible to remove foreign matter adhering to the surface of the photoreceptor.

By separating the twisted portion of multiple fibers forming one loop in the part where the twist becomes tight when sliding against the photoreceptor surface away from the contact position, the twist can be expanded or twisted. This avoids the occurrence of twisted portions at the contact position, and when the loop tip contacts the photoreceptor surface, the brush bristle fibers bend appropriately in the contact range, resulting in a softer and more uniform abrasive and rubbing action. can get. In this case, the twisted portion on the loose side may be formed near the contact range without causing any problem.

According to the present invention, the rubbing action can be easily controlled by appropriately selecting the yarn characteristics of the brush roller. It can be applied to a wide range of surfaces, including those with high surface hardness.

2 times in one loop, once on each side with the contact position in between.
When forming a twist part of 10 times, the number of twists per unit length of brush wool yarn is 2.5 to 4 times/25.4 mm (11 nc
h), the value is within a range that does not impair the handling properties when processed into a textile, and is also necessary and sufficient to maintain the raised state of the brush bristles when used as a brush roller.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the photoreceptor and its surroundings in an example of an image forming apparatus including a cleaning device according to the present invention, FIG. 2 is a partial cross-sectional view showing the entire brush roller, and FIG. 3 is an enlarged view of the bristles of the brush roller. Figure 4 is an enlarged view showing the relationship between the twisting position of the hair loops and the contact range, and Figure 5 is an enlarged view of the twisting of the fibers.
In the explanatory diagrams of movement, (A) is a diagram showing before the twisting action, (B) is a diagram showing after the twisting action, and FIG. 6 is a diagram showing the state in which the loop is in contact with the photoreceptor drum. The example in
B is a diagram showing an example in which the twisted portions are not in the contact position.1...Photoreceptor4. 7... Transfer corona 10... Cleaning device 13... Cleaning blade 14... Brush roller I5... Core material 16... Base fabric 17... Hair 18... Loop 19... Filament 20...Twisted portion 5...Developer Fig. 5 (A) (B) Fig. 6 (A) (B)

Claims (1)

[Claims] (1) A cleaning device for an image forming apparatus that has a rubbing member that rubs the surface of the photoreceptor after the toner image formed on the photoreceptor is transferred to recording paper, and that cleans the surface of the photoreceptor after the transfer. wherein the rubbing member is a brush roller, the bristles of the brush roller are made of a plurality of fibers each having a twisted portion and have a loop at the tip, and the twisted portion is connected between the surface of the photoreceptor and the rubbing member. The twisting position on the side that becomes tight when sliding against the surface of the photoconductor is placed at a position away from the contact point, and is placed at a position away from the contact point by a distance that does not move to the contact point during rubbing. A cleaning device characterized by: