JP2003241603A - Brush roller, cleaning device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device for efficiently removing soil on the circumferential surface of an electrifying roller even in the case the soil at one longitudinal end side of the electrifying roller is remarkably heavier than that at the other end side, as to the cleaning device equipped with a brush roller having a brush coming into contact with the circumferential surface of the electrifying roller and for cleaning the circumferential surface of the electrifying roller with the rotation of the brush roller. <P>SOLUTION: The flextural rigidity of the brush fiber at the one longitudinal end E1 of the brush roller 12 is made higher than that at the other longitudinal end side E2, then, the soil sticking to the one longitudinal end side of the electrifying roller is efficiently removed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush roller, a cleaning device having the brush roller, and an image forming apparatus having the cleaning device.

[0002]

2. Description of the Related Art A cleaning device for cleaning an object to be cleaned has hitherto been widely used in machines and apparatuses in various technical fields. For example, in an image forming apparatus configured as a copying machine, a printer, a facsimile, etc., a cleaning device for cleaning the surface of the image carrier, a cleaning device for cleaning the peripheral surface of a charging roller for charging the image carrier,
Alternatively, a cleaning device or the like for cleaning the surface of the transfer belt is used.

As such a cleaning device, a cleaning device having a brush that contacts the surface of the object to be cleaned and a brush roller that rotates while the brush contacts the object to be cleaned is widely used (for example, JP-A-7-1
40763). The conventional brush roller of this type of cleaning device is configured so that the cleaning ability of the brush is uniform in the longitudinal direction thereof, so that the entire surface of the object to be cleaned can be uniformly cleaned. However, depending on the device or machine in which the object to be cleaned is incorporated, the dirt state on the surface of the object to be cleaned in a direction orthogonal to the moving direction of the surface of the object to be cleaned is not uniform, and part of the dirt is on other parts. It may be more noticeable than dirt. In such a case, if the cleaning ability of the brush roller in the longitudinal direction is constant, there is a possibility that the surface portion of the object to be cleaned which is heavily soiled cannot be sufficiently cleaned. Therefore, it is conceivable that the cleaning ability of the brush roller is increased over the entire length thereof so that the entire surface of the object to be cleaned can be efficiently cleaned. However, when the brush roller is configured in this way, an excessive sliding action is applied to the surface portion of the object to be cleaned, which is less contaminated, and the surface portion of the object to be cleaned is abraded early, which shortens its life. I cannot escape.

[0004]

SUMMARY OF THE INVENTION The present invention has been made based on the above-mentioned novel recognition, and an object of the present invention is to clean a surface of an object to be cleaned even when the surface of the object is not constantly soiled. It is an object of the present invention to provide a brush roller which can improve the ability and can suppress the problem of shortening the life of the object to be cleaned, a cleaning device having the brush roller, and an image forming apparatus having the cleaning device.

[0005]

In order to achieve the above object, the present invention provides a brush roller having a brush, wherein the cleaning ability of the brush in the longitudinal direction of the brush roller is different. Propose (Claim 1).

Further, in order to achieve the above object, the present invention provides a cleaning device having a brush which comes into contact with an object to be cleaned and which rotates while abutting the object to be cleaned. The cleaning device is characterized in that the brush roller is configured such that the cleaning ability of the brush in the longitudinal direction of the brush is different (claim 2).

At this time, it is advantageous that the bending rigidity of the brush fibers of the brush roller portion having the high cleaning ability is set higher than the bending rigidity of the brush fibers of the brush roller portion having the low cleaning ability. 3).

Further, in the cleaning device according to the second or third aspect, the outer diameter of the brush roller portion having the high cleaning ability is set smaller than the outer diameter of the brush roller portion having the low cleaning ability. Advantageous (Claim 4).

Further, according to the present invention, in order to achieve the above object, a charging device, an image carrier charged by the charging device, and an image carrier after charging are exposed to expose an electrostatic latent image on the image carrier. And an developing device for visualizing the electrostatic latent image as a toner image, the developing device carrying a developer having a toner to which an additive is externally added and a carrier. And a developer carrying member that is conveyed in parallel, a first developer carrying member that is disposed substantially parallel to the developer carrying member and is driven to rotate, and a substantially parallel to the first developer carrying member. And a second developer transporting member that is rotatably driven, and the developer transported by the second developer transporting member in the first direction is stored in the second developer transporting member. The first developer is conveyed from one end side in the longitudinal direction to one end side in the longitudinal direction of the first developer carrying member, and The developer delivered to the agent transport member is transported by the first developer transport member in a second direction opposite to the first direction, and the transported developer is transferred to the first developer. From the other end of the carrying member in the longitudinal direction to the other end of the second developer carrying member in the longitudinal direction,
The developer delivered to the second developer transport member is transported in the first direction by the second developer transport member, the developer is circulated and transported, and the first developer transport is performed. The developer conveyed by the member in the second direction is supplied to the developer carrier, and the supplied developer is carried on the developer carrier and the developer carrier and the image carrier are provided. Is conveyed to the developing area between the two, the conveyed developer is used for visualizing the electrostatic latent image, and the additive is added to the developer conveyed by the second developer conveying member. In the image forming apparatus in which the externally added toner is replenished, the charging device includes a charging roller arranged to face the image carrier, and has a cleaning device for cleaning a peripheral surface of the charging roller. The cleaning device is the above-mentioned claim 1.
The cleaning device according to any one of 1 to 4,
The brushes are arranged so that the portions on the one end side in the longitudinal direction of the brush roller, which correspond to the one end sides of the first developer carrying member and the second developer carrying member, have higher cleaning ability than other brush roller parts. An image forming apparatus is proposed in which a roller is configured (Claim 5).

In order to achieve the above object, the present invention exposes the charging device, the image carrier charged by the charging device, and the charged image carrier to the electrostatic latent image on the image carrier. An exposure device that forms an image and a developing device that visualizes the electrostatic latent image as a toner image are provided, and the developing device includes a developer having a toner to which an additive is externally added and a carrier. A developer carrying member which is carried and carried, a first developer carrying member which is arranged substantially parallel to the developer carrying member and is rotationally driven, and a first developer carrying member which is substantially parallel to the first developer carrying member. A second developer carrying member that is arranged in parallel and is driven to rotate, and the developer carried by the second developer carrying member in the first direction is the second developer carrying member. From the one end side in the longitudinal direction of the first developer conveying member to the one end side in the longitudinal direction of the first developer carrying member, The developer delivered to the agent transport member is transported by the first developer transport member in a second direction opposite to the first direction, and the transported developer is transferred to the first developer. From the other end of the carrying member in the longitudinal direction to the other end of the second developer carrying member in the longitudinal direction,
The developer delivered to the second developer transport member is transported in the first direction by the second developer transport member, the developer is circulated and transported, and the first developer transport is performed. The developer conveyed by the member in the second direction is supplied to the developer carrier, and the supplied developer is carried on the developer carrier and the developer carrier and the image carrier are provided. Is conveyed to the developing area between the two, the conveyed developer is used for visualizing the electrostatic latent image, and the additive is added to the developer conveyed by the second developer conveying member. An image forming apparatus in which externally added toner is replenished has a cleaning device for cleaning the surface of the image carrier after transferring the toner image formed on the image carrier to a transfer material, and the cleaning device comprises: The cleaning device according to any one of claims 1 to 4. Therefore, a portion on one end side in the longitudinal direction of the brush roller corresponding to one end side of the first developer conveying member and the second developer conveying member has a higher cleaning ability than other brush roller portions. According to another aspect of the present invention, there is proposed an image forming apparatus in which the brush roller is configured.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a cleaning device of an image forming apparatus will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an example of an image forming apparatus. The image forming apparatus shown here is configured as an electronic copying machine, a printer, a facsimile, or a multifunction machine having at least two functions of these. It is something.

The image forming apparatus shown in FIG. 1 has an image carrier 1 configured as a drum-shaped photosensitive member, and the image carrier 1 is rotationally driven in the direction of arrow A with the start of the image forming operation. To be done. At this time, the charging roller 2, which is an example of a charging device arranged to face the surface of the image carrier, rotates in the direction of arrow B by a driving device (not shown) or following the movement of the surface of the image carrier 1. . The charging roller 2 is composed of a core metal 3 and a resistance layer 4 fixed around the core metal 3, and when the charging roller 2 rotates as described above, a charging voltage of a predetermined polarity is applied to the core metal 3, whereby The surface of the image carrier 1 is charged with a predetermined polarity.

The surface of the charged image carrier 1 is irradiated with a light-modulated laser beam LB emitted from a laser writing unit 30 which is an example of an exposure device, whereby an electrostatic latent image is formed on the surface of the image carrier. Is formed. This electrostatic latent image is visualized as a toner image by the developing device 5.

Further, a transfer belt 8 driven in the direction of arrow E is arranged to face the image carrier 1, and a transfer paper P, which is an example of a transfer material fed from a paper feeding unit (not shown), is The transfer belt 8 is carried and conveyed. When the transfer paper P passes through the transfer area between the image carrier 1 and the transfer belt 8, a transfer voltage is applied to the transfer device 9 arranged to face the image carrier 1 with the transfer belt 8 sandwiched therebetween, whereby the image carrier is carried. The toner image formed on the body surface is electrostatically transferred onto the transfer paper P. It is also possible to transfer the toner image formed on the image carrier onto a transfer material composed of an intermediate transfer material, and transfer the transferred toner image onto a transfer paper which is the final transfer material.

Transfer residual toner adhering to the surface of the image carrier after the toner image is transferred is scraped off by a cleaning member composed of a brush roller 10 and a cleaning blade 11 which are in pressure contact with the surface of the image carrier. On the other hand, the transfer paper P on which the toner image has been transferred passes through a fixing device (not shown),
At this time, the toner image is fixed on the transfer paper by the action of heat and pressure.

In the image forming apparatus shown in FIG. 1, the image carrier 1, the charging roller 2, the brush roller 10 and a brush roller 12 which will be described later are rotatably assembled in the unit case 13, and the base of the cleaning blade 11 is used. The ends are fixed to the unit case 13, and these elements constitute an integral process cartridge 14. The process cartridge 14 can be loaded at a predetermined position by pulling the process cartridge 14 toward the front side or pushing it toward the back side along the guide rails 15 fixed to the image forming apparatus main body. A cleaning case 16 formed of the brush roller 10, the cleaning blade 11, and a part of the unit case 13 constitutes a cleaning device 17 for the image carrier that cleans the surface of the image carrier.

The charging roller 2 faces the image carrier and charges the image carrier 1 as described above. The roller 2 may be in pressure contact with the surface of the image carrier 1 as shown in FIG. 1, but a minute gap is formed from the surface of the image carrier 1 and the roller 2 is positioned in a non-contact state with respect to the image carrier. You may have.

As described above, the image forming apparatus of this embodiment includes the charging device, the image carrier charged by the charging device,
An exposure device that exposes the charged image carrier to form an electrostatic latent image on the image carrier, and a developing device that visualizes the electrostatic latent image as a toner image are provided. This developing device is configured as follows.

FIG. 2 is a plan sectional view taken along the line II--II of FIG. 1, and the developing device 5 has a dry developer D (see FIG. 2), as is apparent from FIGS. (Not shown) is contained in the developing case 6, and a developer carrier 7 in which a magnet (not shown) is fixedly arranged is provided. Although the developer carrying member composed of the developing roller is used here, a developer carrying member composed of an endless belt or the like may be used. The developer D used here is a two-component developer having a toner to which an additive is externally added and a magnetic carrier. The developer carrying member 7 is rotationally driven in the direction shown by the arrow in FIG. 1, and the developer D supplied to the peripheral surface of the developer carrying member 7 is developed by the magnetic force of the magnet. The toner in the developer carried on the peripheral surface of the image carrier 7 and conveyed in the direction of the arrow and carried between the developer carrier 7 and the image carrier 1 is an electrostatic latent image formed on the image carrier 1. And the latent image is visualized as a toner image. As described above, the developer carrying member serves to carry and carry the developer having the toner to which the additive is externally added and the carrier.

In the developing device 5 of this embodiment, the first developer carrying member 31 is disposed substantially parallel to the developer carrying member 7 and is driven to rotate, and the first developer carrying member 31.
And a second developer carrying member 32 which is arranged substantially parallel to and is driven to rotate. In the illustrated example, these developer carrying members 31, 32 are constituted by a carrying screw. . As is apparent from FIG. 2, the first and second developer transport members 31, 32 and the developer carrier 7
Is axially rotatably supported at each side wall of the developing case 6, and is rotationally driven around its central axis by a driving device (not shown). The first and second developer transport members 31 and 32 are arranged in the first and second spaces S1 and S2 in the developing case 6 defined by the partition wall 33 arranged therebetween.

Here, the first and second developer transport members 3
One end side and the other end side of each of the longitudinal end regions 1 and 32 are defined as one end side, and in the illustrated example, the right end side of the developer transport members 31 and 32 in FIG. Suppose there is. In FIG. 2, reference characters E1,
E2 is attached. Further, each end area in the axial direction of the image carrier 1 corresponding to the one end side E1 and the other end side E2 of the first and second developer transport members 31 and 32, and the charging roller 2 respectively.
The respective longitudinal end regions and the longitudinal end regions of the brush roller 12 will also be referred to as one end side E1 and the other end side E2, respectively. The partition wall 33 does not exist on the one end side E1 and the other end side E2 of the first and second developer transport members 31 and 32, and the respective parts that do not exist are the first and second openings 34 and 35. And each of the openings 34, 35
The first and second spaces S1 and S2 communicate with each other through.

By the rotation of the second developer carrying member 32, the developer in the second space S2 is carried in the first direction indicated by the arrow J1 in FIG. In this way, the developer carried by the second developer carrying member 32 in the first direction J1 is
The first developer carrying member 3 passes through the first opening 34 from one end E1 in the longitudinal direction of the second developer carrying member 32.
1 is transferred to one end E1 in the longitudinal direction. Then, the developer transferred to the first developer carrying member 31 is carried by the first developer carrying member 31 in the second direction J2 opposite to the first direction J1, and then carried. The generated developer is supplied from the other end E2 in the longitudinal direction of the first developer carrying member 31 to the second developer carrying member 3 through the second opening 35.
The developer delivered to the other end E2 in the longitudinal direction of 2 and delivered to the second developer transport member 32 is transported in the first direction J1 by the second developer transport member 32. In this way, the developer is agitated while being circulated and conveyed, and the toner and the carrier are triboelectrically charged with opposite polarities.

The developer conveyed in the second direction J2 by the first developer conveying member 31 is supplied to the peripheral surface of the developer carrying member 7 and, as described above, the supplied development. The developer is carried on the developer carrying body 7 and is carried to a developing area between the developer carrying body 7 and the image carrying body 1, and the carried developer makes a visible image of an electrostatic latent image. Be used for. The developer which has passed through the developing area is separated from the developer carrier 7 and is further moved by the first developer transport member 31 in the second direction J2.
Is transported to and circulated.

When the decrease in the toner concentration of the developer in the developing case 6 is detected by a sensor (not shown), the toner sent from the toner container of the toner replenishing device (not shown) is used as the second developer carrying member. The toner is replenished into the developing case 6 through a toner replenishing port formed in the developing case portion above 32. In FIG. 2, the position of the toner supply port 36 is shown by a chain line.

The toner supplied to the developing case 6 as described above first drops onto the second developer carrying member 32, is agitated by the second developer carrying member 32, and is then agitated by the developer carrying member 32. While being mixed with the developer transported in the first direction J1, the developer moves to the first space S1 through the first opening 34 together with the developer. As described above, in the developing device 5 of this example, the toner to which the additive is added is replenished and conveyed in the developer conveyed by the second developer conveying member 32.

By the way, when the image forming operation is performed as described above, the cleaning device 17 removes the transfer residual toner on the image carrier, but it is difficult to remove all the toner, and a small amount of toner remains. Cleaning blade 11
Slip through. The foreign matter such as the toner that has slipped through in this way and the toner that floats in the main body of the image forming apparatus adheres to the peripheral surface of the charging roller 2. If left unattended, uneven charging or defective charging of the image carrier occurs, and the image quality of the toner image formed on the image carrier deteriorates.

Therefore, the image forming apparatus of this embodiment is provided with the cleaning device 18 for the charging roller, which is equipped with the brush roller 12 described above. The charging device comprises the charging roller 2 arranged so as to face the image carrier 1, and the cleaning device 18 for cleaning the peripheral surface of the charging roller 2 is provided.

The brush roller 12 extends parallel to the charging roller 2, and as shown in FIGS. 3 and 4, a core shaft 19 made of a rigid body such as metal or hard resin, and this core shaft 19
It has a brush 20 made of a large number of fibers, the base end of which is fixed to the peripheral surface of the brush. The brush 20 is provided over the entire circumference of the core shaft 19 in the range indicated by the symbol W in FIG. As shown in FIGS. 1 and 3, the brush roller 12 has a brush 20 to be cleaned, which is the charging roller 2 in this example.
The surface of the charging roller 2 is cleaned by rotating while contacting the surface of the charging roller 2.

The brush roller 12 may be pressed against the peripheral surface of the charging roller 2 by a pressing means such as a compression spring (not shown), or the brush roller 12 may be rotationally driven by a driving device (not shown). In the brush roller 12 of this example, the brush 20 is
It is arranged so as to come into contact with the body to be cleaned, that is, the surface of the charging roller 2 by its own weight, and to rotate in the direction of arrow G following the movement of the surface of the body to be cleaned.

Specifically, as shown in FIGS. 1 and 3,
The side member 13A on the back side of the unit case 13 and the side plate (not shown) on the front side are provided with the bearing member 2 as shown by a chain line in FIG.
1 is fixed to each of the bearing members 21, and guide slots 22 each having an open lower portion are formed in each of the bearing members 21, and each longitudinal end portion of the core shaft 19 of the brush roller 12 is rotatably attached to each guide slot 22. Further, it is slidably fitted along the guide slot 22 in the direction of arrow F (direction toward or away from the surface of the object to be cleaned). The width of each guide slot 22 is set to be slightly larger than the diameter of each end of the core shaft 19, so that each end of the core shaft 19 can fit into each guide slot 22 without rattling.

The brush roller 12 is located in the upper region of the charging roller 2 and each end of the core shaft 19 is slidably fitted in the guide slot 22. 20 contacts the surface of the charging roller 2 by its own weight. Moreover, the core shaft 19
Since each end of the brush roller 12 is rotatably fitted in the guide slot 22, the brush roller 12 follows the movement of the surface of the charging roller 2 when the charging roller 2 rotates in the arrow B direction. Can be rotated. Brush roller 1
2 rotates with the rotation of the charging roller 2, and the brush 20 contacting the surface of the charging roller 2 at this time removes the toner adhering to the surface of the charging roller 2 and cleans the surface.

By the way, as described above, the brush roller of the conventional cleaning device is constructed so as to have uniform cleaning ability in the longitudinal direction, but this causes the following drawbacks. Occurs.

As described above, the fresh toner replenished into the developing case 6 of the developing device 5 from the toner replenishing device (not shown) is conveyed by the second developer conveying member 32 to generate the first developer. It is delivered to the transport member 31. The developer containing fresh toner is gradually transferred from one side in the longitudinal direction of the developer carrier 7 to the peripheral surface of the developer carrier 7.

The problem here is the additive contained in the toner. Various additives are used to increase the fluidity of the toner and to improve the image quality, but some of them are more likely to migrate to the image carrier surface than the resin that constitutes the toner particles. There are also things. Therefore, from the second developer transport member 32 to the first developer transport member 31.
The additive in the fresh toner, to which the developer has been delivered, immediately adheres to the peripheral surface of the developer carrier 7 as indicated by a broken line arrow I in FIG. 2, and the additive is added at an early stage to the image carrier 1.
Move to the surface of. In this way, on the peripheral surface of the image carrier, a larger amount of the additive is attached to one end side of the image carrier corresponding to one end side of the developer carrying members 31 and 32 in the axial direction of the image carrier, compared to the other portions. The additive passes through the cleaning device 7 and adheres to the peripheral surface of the charging roller 2. Therefore, the one end side E of the first developer carrying member 31 and the second developer carrying member 32
A large amount of the additive adheres to the portion on the one end side of the charging roller 2 corresponding to No. 1, and the amount of contamination on one end side of the charging roller 2 increases, and the amount of contamination decreases toward the other end side of charging roller 2. Therefore, the conventional brush roller having a constant cleaning ability in the longitudinal direction cannot sufficiently remove the dirt on the one end side of the charging roller 2, and the charging ability for the image carrier portion corresponding to the charging roller portion is lowered. Then
The image carrier cannot be charged uniformly, which deteriorates the image quality and may cause an abnormal image.

Therefore, the brush roller 12 of the cleaning device 18 of this example is constructed so that the cleaning ability of the brush 20 in the longitudinal direction is different. More specifically, the portion on the one end side E1 (FIG. 4) in the longitudinal direction of the brush roller 12 corresponding to the one end side E1 of the first developer carrying member 31 and the second developer carrying member 32 is the other brush. The brush roller 12 is constructed so as to have a cleaning ability higher than that of the roller portion.

With the above construction, the charging roller 2 having a large amount of dirt locally can be uniformly cleaned over the entire length thereof, uneven charging of the image carrier 1 can be eliminated, and a high quality image can be formed. You can Further, since the cleaning ability is not increased over the entire length of the brush roller 12, the brush does not exert an excessively large rubbing force on the charging roller portion that is less contaminated, and the charging roller portion can be quickly moved. It is possible to prevent the problem of wear.

Various specific configurations for changing the cleaning ability of the brush roller 12 can be adopted. For example, the bending rigidity of the brush fiber on the one end side E1 in the longitudinal direction of the brush roller 12 shown in FIG. 4 is set to be higher than the bending rigidity of the brush fiber of the other portion. A brush with a large bending rigidity is a charging roller.
Since it strongly hits the peripheral surface of No. 2, its cleaning ability is enhanced and dirt on the peripheral surface of the charging roller can be efficiently removed.
At that time, from one end side E1 of the brush roller 12 to the other end side E2
The bending rigidity of the brush 20 may be gradually reduced toward the bottom, or the brush roller 12 may be divided into a plurality of portions W1, W2, W3, W4, W5 in the longitudinal direction thereof.
The bending rigidity of the brush 20 may be gradually reduced from the portion W1 to the portion W5. That is, the bending rigidity of the brush is set to W1>W2>W3> W4.
> W5 is set.

As described above, by setting the bending rigidity of the brush fiber of the brush roller portion having high cleaning ability higher than the bending rigidity of the brush fiber of the brush roller portion having low cleaning ability, the brush roller in the longitudinal direction of the brush roller is The cleaning ability of the brush can be different.

Instead of or in addition to the above configuration, the outer diameter of the brush roller portion having high cleaning ability is set to be smaller than the outer diameter of the brush roller portion having low cleaning ability. The brush cleaning ability can be different. Specifically, as illustrated in FIG. 5, the core shaft 1 of the brush roller 12
The brush roller 12 is configured such that the outer diameter of 9 gradually increases from one end E1 in the longitudinal direction toward the other end E2. As a result, the brush roller 12 is moved to the other end side E2.
Becomes heavier than the end E1 and the brush roller 1
The pressure at which 2 comes into contact with the surface of the charging roller 2 is E1 on the one end side.
The other end E2 is larger than the other end. Therefore, the other end side E2 of the brush roller 12 rotates together with the charging roller 2, and the surface linear velocity of the other end side E2 of the brush roller 12 becomes substantially equal to the surface linear velocity of the charging roller 2. Therefore, the surface linear velocity of the one end side E1 of the brush roller 12 having an outer diameter smaller than that of the other end side E2 of the brush roller 12 becomes slower than the surface linear velocity of the charging roller 2, and the linear velocity difference between them is small. The brush portion on one end E1 of the brush roller 12 is
Since the charging roller 2 is rubbed against the charging roller 2, its cleaning ability is higher than that of the other end side E2. This makes it possible to efficiently remove a large amount of dirt attached to one end of the charging roller 2, that is, the additive.

When the brush roller 12 is positively rotated by a driving device instead of rotating the brush roller 12 around the charging roller 2, the surface linear velocity of the other end E2 of the brush roller 12 is, for example, If the brush roller 12 is driven so that is substantially equal to the surface linear velocity of the charging roller 2, the same result as described above can be obtained.

In any of the above-mentioned examples, since the rubbing force between the other end side E2 of the brush roller 12 and the other end side of the charging roller 2 with less dirt can be kept small, the circumference of the charging roller 2 with less dirt. An excessively large rubbing force is not exerted on the surface portion, and the problem of accelerated wear can be prevented.

Since the brush roller 12 of the cleaning device 18 shown in the drawing is not driven to rotate by the driving device but rotates following the rotation of the charging roller 2,
A drive device that rotationally drives the brush roller 12 is not required, which simplifies the configuration of the cleaning device 18 and reduces the cost thereof.
Moreover, since the brush 20 does not hit the surface of the charging roller 2 excessively, abrasion of the surface of the charging roller 2 can be suppressed.

The sum of the radius of the brush roller 12 and the radius of the charging roller 2 when the brush roller 12 is not in contact with the charging roller 2 indicates that the brush roller 12 is in contact with the charging roller 2. The value obtained by subtracting the distance between the center of the brush roller 12 and the center of the charging roller 2 is the bite amount of the brush 20, but if the bite amount is too large, the fibers of the brush 20 deteriorate early. As a result, the brush is permanently deformed, and the brush collapses. On the contrary, when the amount of the bite of the brush is too small, the cleaning efficiency of the surface of the charging roller 2 decreases. It is possible to regulate the amount of bite of the brush by adjusting the relative position between the center of the brush roller and the center of the charging roller by the regulating means so that the distance between them is constant, but if such regulating means is provided, This increases the cost of the cleaning device and complicates its structure.

On the other hand, the cleaning device 18 of this example
In the above, since the brush roller 12 is configured to contact the surface of the charging roller 2 by its own weight,
By simply adjusting the weight of the brush roller 12, the desired amount of bite of the brush can be obtained, and the above-mentioned regulating means can be omitted. As a result, the structure of the cleaning device 18 can be simplified and the cost can be reduced.

The length of the fibers of the brush 20 can be appropriately set, but it is desirable to set this length to 2 mm or less, particularly 0.4 to 0.6 mm. The length of this fiber is the length of the free fiber portion excluding the fiber portion fixed to the core shaft 19. By shortening the length of the fiber in this way, it is possible to reduce the bending moment acting on the base end portion of the fiber elastically bent and deformed by being pressed against the surface of the charging roller 2. As a result, the occurrence of brush collapse (permanent deformation) can be suppressed more effectively over a long period of time, and the life of the brush roller 12 can be extended. If the fiber length of the brush 20 is longer than 2 mm, the distance between the fibers at the tip end of the fiber becomes large, and thus the load applied to each fiber contacting the surface of the charging roller 2 becomes large, whereby the brush is Although there is a possibility that the collapse of the fiber may be promoted, such a problem can be avoided by setting the fiber length to 2 mm or less.

In order to remove the toner adhering to the tip of the brush of the brush roller, the brush may be hit against a flicker, but if the fiber length of the brush 20 is shortened as described above. As shown in FIG. 1, the toner adhering to the tip of the brush can be removed without hitting the brush 20 against the flicker.
The reason is not necessarily clear, but when the fiber has a short length of 2 mm or less, the fiber elastically deformed by being pressed against the surface of the charging roller 2 is removed from the charging roller 2 as the brush roller 12 rotates. It is considered that the toner attached to the tip portion of the fiber jumps out from the fiber due to the impact at this time because the original shape is instantly elastically restored when it is separated.

The thickness and the density of the fibers of the brush 20 can be appropriately set. However, the thickness is set to 2 denier or less and the density of the fibers is 20000 fibers / cm ² or more, particularly 300.
When it is set to 00 fibers / cm ² , a large number of fibers come into contact with the surface of the charging roller 2, whereby the load applied to each fiber can be reduced. This also makes it possible to prevent the brush from falling over a long period of time. Further, if the density of the fibers is increased in this way, the number of fibers abutting on the surface of the charging roller increases, so that the surface of the charging roller 2 can be efficiently cleaned and the stain unevenness can be eliminated, and the image carrier 1 It is possible to always form a high quality image on the top.

The weight of the brush roller 12 can also be set as appropriate. Particularly, if the weight is set to 50 g or more and 200 g or less, an appropriate bite amount of the brush 20 can be guaranteed and the brush roller 12 can be smoothly rotated. It becomes possible. If the weight of the brush roller 12 is less than 50 g, the amount of the bite of the brush becomes too small, and the cleaning efficiency of the surface of the charging roller 2 decreases, and the weight is 20%.
If it is larger than 0 g, the amount of bite of the brush becomes excessively large, and the collapse of the brush is easily promoted.

The brush 20 can be fixed to the core shaft 19 by an appropriate method. Particularly, when the fiber base end portion of the brush 20 is fixed to the peripheral surface of the core shaft 19 of the brush roller by the electrostatic flocking method. The short fibers can be highly densely planted on the core shaft 19. As a result, it is possible to prevent the brush from falling over a long period of time, and the brush roller 1
It is possible to extend the life of 2.

For example, an adhesive is applied to the range W (FIG. 4) of the core shaft 19, the base ends of a large number of fibers are electrostatically attached to the adhesive, and the base ends of the fibers are bonded. It can be fixed to the core shaft 19 via an agent.

The material of the fibers of the brush can be appropriately selected,
According to experiments, it has been confirmed that when the fiber is made of a resin such as nylon 66 or PET (polyethylene terephthalate), the collapse of the brush can be effectively suppressed and an appropriate bite amount can be obtained.

If the fibers of the brush are made of a material capable of electrostatically attracting the toner adhering to the charging roller 2 to the brush, the efficiency of cleaning the surface of the charging roller 2 can be further improved.

When the member to be cleaned is composed of a rotating member formed in a cylindrical shape like the charging roller 2 shown in FIG. 1,
As shown in FIG. 6, when the brush roller 12 is brought into contact with the range S of the peripheral surface of the rotating body above the horizontal line H passing through the rotation center O of the rotating body 2A, the brush roller 12 is urged by its own weight. 20 can be brought into contact with the rotating body without any trouble.

An example of the cleaning device in which the cleaning target is the charging roller 2 that faces the image bearing member 1 and charges the image bearing member 1 has been described above, but various cleaning targets other than the charging roller 2 are described. The cleaning device having each of the above-described configurations can be used for cleaning the above. For example, the image forming apparatus shown in FIG. 1 has a cleaning device 17 for cleaning the surface of the image carrier after transferring the toner image formed on the image carrier to a transfer material. The brush roller 10 may be configured in the same manner as the brush roller 12 described above, and the configurations described above may be applied to the cleaning device 17 for the image carrier. In that case, the portion on the one end side in the longitudinal direction of the brush roller 10 corresponding to the one end side E1 of the first developer conveying member 31 and the second developer conveying member 32 has a cleaning ability higher than that of the other brush roller 10. The brush roller 10 is configured so that

In addition, in order to remove the transfer residual toner adhering to the above-mentioned intermediate transfer member, a cleaning device having the above-mentioned brush roller can be used, and cleaning for removing the toner adhering to the transfer belt 8 is also possible. The above-described respective configurations can be adopted for the device.

[0057]

According to the present invention, even if the dirt on the surface of the object to be cleaned is not constant, the cleaning ability of the surface can be enhanced and the life of the object can be shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus.

FIG. 2 is a cross-sectional view of the developing device taken along line II-II in FIG.

FIG. 3 is an enlarged view of a brush roller.

FIG. 4 is a front view of a brush roller.

FIG. 5 is a front view showing another example of the brush roller.

FIG. 6 is a diagram illustrating an arrangement position of brush rollers with respect to an object to be cleaned.

[Explanation of symbols]

1 Image carrier 2 charging roller 5 Development device 7 Developer support 10 brush roller 12 brush roller 17 Cleaning device 18 Cleaning device 20 brushes 31 First Developer Conveying Member 32 Second Developer Transport Member E1 One end side E2 the other end D developer J1 first direction J2 second direction

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 103 B41J 29/00 J 3B202 15/08 507 G03G 15/08 507E F term (reference) 2C061 AP03 AP04 AQ06 CM07 2H071 BA41 DA06 DA08 DA13 2H077 AB02 AB06 AB14 AB15 AB18 AC02 AD06 BA02 EA01 2H134 GA01 GA02 GB02 HB01 HB05 KG01 KG03 KH15 2H200 GA23 GA49 GB13 HA02 HA28 HB12 HB22 JB42 JC12 LB02 LB08 LB12 LB35 LB37 MA04 MC04 MC11 3B202 AA30 BA03 BC01 BE09 EA01

Claims (6)

[Claims] 1. A brush roller having a brush, comprising:
A brush roller having different brush cleaning abilities in the longitudinal direction of the brush roller. 2. A cleaning device comprising a brush roller that abuts on a body to be cleaned, and the brush roller rotates while abutting the body to be cleaned, wherein the cleaning ability of the brush in the longitudinal direction of the brush roller is different. The cleaning device is characterized in that the brush roller is configured as described above. 3. The cleaning device according to claim 2, wherein the bending rigidity of the brush fibers of the brush roller portion having high cleaning ability is set higher than the bending rigidity of the brush fibers of the brush roller portion having low cleaning ability. . 4. The cleaning device according to claim 2, wherein the outer diameter of the brush roller portion having high cleaning ability is set smaller than the outer diameter of the brush roller portion having low cleaning ability. 5. A charging device, an image carrier that is charged by the charging device, an exposure device that exposes the charged image carrier to form an electrostatic latent image on the image carrier, and the electrostatic device. A developing device that visualizes the latent image as a toner image, the developing device carrying a developer having a toner to which an additive is externally added and a carrier, and carrying the developer; A first developer carrying member which is arranged substantially parallel to the developer carrying member and is rotationally driven, and a second developer carrying member which is arranged substantially parallel to the first developer carrying member and is rotationally driven. And a developer transported by the second developer transporting member in the first direction from the one end in the longitudinal direction of the second developer transporting member. The developer transferred to the one end side in the longitudinal direction of the agent transfer member and transferred to the first developer transfer member is One developer transport member transports the developer in a second direction opposite to the first direction, and the transported developer is transported from the other end side in the longitudinal direction of the first developer transport member to the second direction. The developer delivered to the other end of the developer transport member in the longitudinal direction and delivered to the second developer transport member is transported in the first direction by the second developer transport member, The developer is circulated and conveyed, the developer conveyed in the second direction by the first developer conveying member is supplied to the developer carrier, and the supplied developer is
The developer carried on the developer carrying body is conveyed to a developing area between the developer carrying body and the image carrying body, and the carried developer is used for visualizing the electrostatic latent image, In the image forming apparatus, in which the toner externally added with the additive is replenished in the developer conveyed by the second developer conveying member, the charging device is arranged to face the image carrier. The cleaning device comprises a charging roller and a cleaning device for cleaning a peripheral surface of the charging roller, and the cleaning device comprises the cleaning device according to any one of claims 1 to 4, The brush roller is configured such that a portion on one end side in the longitudinal direction of the brush roller corresponding to one end side of the member and the second developer transporting member has a higher cleaning ability than other brush roller portions. Image shape characterized by Equipment. 6. A charging device, an image carrier that is charged by the charging device, an exposure device that exposes the charged image carrier to form an electrostatic latent image on the image carrier, and the electrostatic device. A developing device that visualizes the latent image as a toner image, the developing device carrying a developer having a toner to which an additive is externally added and a carrier, and carrying the developer; A first developer carrying member which is arranged substantially parallel to the developer carrying member and is rotationally driven, and a second developer carrying member which is arranged substantially parallel to the first developer carrying member and is rotationally driven. And a developer transported by the second developer transporting member in the first direction from the one end in the longitudinal direction of the second developer transporting member. The developer transferred to the one end side in the longitudinal direction of the agent transfer member and transferred to the first developer transfer member is One developer transport member transports the developer in a second direction opposite to the first direction, and the transported developer is transported from the other end side in the longitudinal direction of the first developer transport member to the second direction. The developer delivered to the other end of the developer transport member in the longitudinal direction and delivered to the second developer transport member is transported in the first direction by the second developer transport member, The developer is circulated and conveyed, the developer conveyed in the second direction by the first developer conveying member is supplied to the developer carrier, and the supplied developer is
The developer carried on the developer carrying body is conveyed to a developing area between the developer carrying body and the image carrying body, and the carried developer is used for visualizing the electrostatic latent image, In the image forming apparatus, in which the toner externally added with the additive is replenished in the developer conveyed by the second developer conveying member, the toner image formed on the image carrier is transferred to a transfer material. A cleaning device for cleaning the surface of the image bearing member after that is provided, and the cleaning device comprises the cleaning device according to any one of claims 1 to 4, wherein the first developer conveying member and the second developing device are provided. Image forming, characterized in that the brush roller is configured such that a portion on one end side in the longitudinal direction of the brush roller corresponding to one end side of the agent transport member has a higher cleaning ability than other brush roller portions. apparatus.