JP2002049227A - Image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-forming device, capable of more effectively cleaning an electrifying member, taking into consideration the tilting property that a brush has. SOLUTION: A contact/separate direction A where the brush of a cleaning member 10 contacts with/separates from the electrifying member 9 and a tilting direction B, where brush flocked fibers 10a are tilted by the tilting property are set to be in reverse direction to each other. Thus, the abutting of the flocked fibers 10a on the member 9 is nearly uniform over the entire shaft direction of the member 9 and becomes stable, so that the member 9 is cleaned more surely and more completely. When the flocked fibers 10a separate from the member 9, toner stuck to the member 9 is flicked by the elastic restoring force of the flocked fibers 10a and the adhesive force of the toner to the member 9 is made weak.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an image by charging a photosensitive member by bringing a charging device such as a charging roller into contact with the photosensitive member and forming an electrostatic latent image on the charged photosensitive member. The invention belongs to the technical field of an image forming apparatus, and particularly to the technical field of an image forming apparatus in which a charging member of a charging device is cleaned by a cleaning member.

[0002]

2. Description of the Related Art An image forming apparatus such as an electrostatic copying machine or a printer is provided with a charging device for charging a photosensitive member, and corona charging has been widely used as a charging device. However, since the corona charging generates ozone and nitrogen oxides and adheres to the surface of the photoreceptor, there is a problem that an image defect is caused.

A contact charging system in which a charging member made of, for example, urethane rubber or the like to which a voltage is applied is brought into contact with the photosensitive member to charge the photosensitive member is proposed in Japanese Patent Laid-Open No. 63-149668. Have been. According to the contact charging method, the problem caused by the corona charging described above is solved. However, in the contact charging method, since the charging member is in contact with the photoreceptor, foreign substances such as toner on the photoreceptor slipped from the cleaning device and toner scattered from the developing device adhere to the surface of the charging member. For this reason, charging failure of the photoconductor is caused, and image deterioration occurs.

[0004] For this reason, various image forming apparatuses provided with a cleaning member for removing foreign substances such as toner adhered to the surface of the charging member have been conventionally proposed. When the cleaning member of such an image forming apparatus is constantly in contact with the charging member, the surface of the charging member is damaged and charging failure occurs. The cleaning member is brought into contact with the charging member only when cleaning the charging member, and is set to be separated from the charging member when not cleaning the charging member. In this case, the cleaning of the charging member is generally performed regularly, and therefore, the operation of separating and connecting the cleaning member is also performed regularly. According to the image forming apparatus including the cleaning member, the surface of the charging member is cleaned,
The charging of the photoconductor is improved.

The timing at which the cleaning member is separated from and connected to the charging member is described in JP-A-6-393.
No. 0 discloses a method of performing a separating / contacting operation when the charging member is rotating.
Japanese Patent No. 3208 discloses a method for simultaneously performing the rotation and the separation / contact operation of the charging member. Further, as a method of moving the cleaning member toward and away from the charging member, in most of the conventional image forming apparatuses, the cleaning member is moved in the radial direction of the charging member. Further, a method of cleaning the charging member by simply reciprocating the cleaning member in the axial direction of the charging member without performing the separation / contact operation of the cleaning member is also disclosed in, for example, JP-A-7-110618 and JP-A-7-134474.
No. pp. 147-64.

On the other hand, as a cleaning member for the charging member, a brush is used as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-168422, and this brush does not damage the surface of the charging roller, and Adjustment of the contact pressure of the cleaning member is not required, and the occurrence of uneven charging due to streaking on the surface of the charging roller is prevented.

[0007]

By repeating the cleaning of the charging member, the removed toner gradually accumulates in the cleaning member. The cleaning member in which the toner is accumulated is brought into contact with a rotating charging member as disclosed in JP-A-6-3930, or is cleaned as disclosed in Japanese Patent No. 2853208. If the charging member is rotated at the same time as the separating / contacting operation of the member, the cleaning member may be hit by the rotation of the charging member at the moment when the cleaning member comes into contact with or separates from the charging member. When the cleaning member is hit by the rotation of the charging member, the toner accumulated in the cleaning member scatters. Then, the scattered toner contaminates the inside of the process cartridge in which the photosensitive member or the like is stored or the inside of the image forming apparatus main body, thereby deteriorating the image quality.

Further, in the cleaning device for a charging member having a cleaning member separating / contacting mechanism, when the cleaning member separates from the charging member, the charging is performed by toner accumulated in a nip portion where the charging member contacts the cleaning member. A so-called separation streak may occur on the member, but the separation streak causes the following problem. That is, (1) not only a part of the separation streaks remains on the charging member in a streak shape with respect to the rotation direction of the charging member, but also because the cleaning member is separated and moved in a radial direction, the same portion is always streaked. And it causes charging failure. (2) Some of the toner on the separation streak moves to the photoconductor, but some of the other toner falls under the charging member and accumulates each time the separation / contact operation is performed. It contaminates the inside of the forming apparatus and deteriorates the quality of the image forming apparatus.

Accordingly, the present applicant has filed a patent application for an image forming apparatus which solves such a problem (Japanese Patent Application No. 11-1).
No. 95953). In the image forming apparatus of this patent application, the cleaning member comes into contact with the charging member while moving in the axial direction.

Incidentally, it is conceivable to use a brush as a cleaning member for the charging member in the image forming apparatus as disclosed in this patent application. However, due to the manufacturing process of the brush, there are a direction in which the brush bristle easily falls and a direction in which the brush does not easily fall when the brush bristle vertically contacts the charging member. In other words, the brush flocking has a falling behavior of falling in almost one direction when a load is applied by being uniformly abutted perpendicularly to a member extending in the longitudinal direction of the brush and over the entire longitudinal direction of the brush. For example, as shown in FIG. 4A, the cleaning member 10 is formed by a brush composed of a large number of brush flocked members 10a, and these brush flocked members 10a are supported vertically upright on the support member 11 in a free state where no load is applied. In this state, when a load is applied to the brush flocking 10a by bringing the brush flocking 10a into contact with the member α extending in the longitudinal direction of the brush perpendicularly and uniformly over the entire longitudinal direction of the brush, FIG. As shown in FIG. 4, the brush flocking 10a has a falling direction B in which the brush flocking 10a falls leftward with respect to the supporting member 11, or a falling direction C in which the brush flocking 10a falls rightward as shown in FIG. It has the habit of falling down.

[0011] As described above, if the fall behavior of the brush flocking varies depending on the brush, depending on how the brush falls,
The abutment load of the brush on the charging member is different and tends to be unstable. For this reason, uneven cleaning occurs and the cleaning ability is reduced. For this reason, there is a problem in that the charging member is not sufficiently cleaned, and charging unevenness occurs as described above, thereby lowering the charging ability and significantly deteriorating the image quality.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and has as its object to provide an image forming apparatus capable of more effectively cleaning a charging member in consideration of the falling behavior of a brush. It is to provide a device.

[0013]

In order to solve this problem, the present invention is directed to a photosensitive member on which an electrostatic latent image is formed, and a charging member for charging the photosensitive member by contacting the photosensitive member. And at least a cleaning member that is provided detachably with respect to the charging member and cleans the charging member, by rotating the charging member in a state where the cleaning member is in contact with the charging member. In the image forming apparatus configured to perform cleaning of the charging member, the cleaning member is formed of a brush made of a large number of brush flocked pieces, and the brush flocked is in a free state uniformly and in a longitudinal direction of the brush. It has a falling behavior of falling in one direction when a load is applied vertically, and the direction of separation and contact of the cleaning member with respect to the charging member is set to be oblique in the axial direction and the radial direction of the charging member. To, it is characterized in that falling direction due to the inclination behavior of the brush bristles of the cleaning member is set to disjunction direction opposite to the direction of the cleaning member.

[0014]

In the image forming apparatus of the present invention having the above-described configuration, when the brush of the cleaning member moves in the axial direction and the diagonal direction in the radial direction and contacts the charging member for cleaning the charging member, the brush is moved. The brush flock falls down in a direction opposite to the direction in which the brush abuts on the charging member due to its falling behavior. As described above, when the brush flock falls in the falling direction, which is the falling habit of the brush in contact with the charging member, the brush flock falls smoothly without resistance. As a result, the bristle bristle becomes substantially uniform and largely falls over the entire longitudinal direction of the brush. Therefore,
The contact of the brush flock with the charging member is substantially uniform over the entire axial direction of the charging member and is stable, and the cleaning of the charging member is performed uniformly.

When the cleaning of the charging member by the cleaning member is completed, the brush is separated from the charging member obliquely in the original direction. At this time, the brush flocking is greatly inclined in the direction opposite to the direction in which the brush is separated. Therefore, the elastic restoring force for returning to the original state is large. For this reason, the brush flocking is a large elastic restoring force at the time of separation from the charging member, and repels foreign matters such as toner still sticking to the charging member even after cleaning, so that the adhesive force of the foreign matter such as toner to the charging member is weakened. As a result, the foreign matter adheres to the charging member in a substantially floating state. Therefore, foreign substances such as toner stuck to the charging member can be more easily removed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view schematically showing a full-color intermediate transfer type image forming apparatus to which an embodiment of the image forming apparatus according to the present invention is applied, and FIG. It is a figure which shows a relationship typically. As shown in FIG. 1, the image forming apparatus 1 of this example includes a photoconductor (hereinafter also referred to as OPC) 2, a charging device 3, an exposure device 4, a developing device 5, an intermediate transfer device 6, and a cleaning device 7. And a transfer device (not shown) for transferring the intermediate transfer image transferred to the transfer belt 6a of the intermediate transfer device 6 to a transfer material such as transfer paper, and a fixing device for fixing the transfer image transferred to the transfer material. ing.

The charging device 3, the exposing device 4, the developing device 5, the intermediate transfer device 6, and the cleaning device 7 are disposed around the OPC 2 in the same order as in the conventional image forming apparatus, clockwise in FIG. I have. The charging device 3 in the image forming apparatus 1 of this example includes an OPC 2 as shown in FIG.
A charging member 9 such as a charging roller for charging the OPC 2 by contacting the charging member 9; a cleaning member 10 which is detachable from the charging member 9 and cleans the surface when the charging member 9 is contacted; As shown by arrows, a holding member 11 is provided so as to be movable obliquely in the vertical and horizontal directions, that is, in the axial direction of the rotating shaft 9 a of the charging member 9 and in the radial direction of the charging member 9. Therefore, the cleaning member 10 is also in the axial direction of the rotation shaft 9a of the charging member 9 and in the charging member 9 direction.
Can be moved obliquely in the radial direction of the cleaning member 10
2 can move in the diagonally lower right direction and contact the charging portion 9b of the charging member 9 in FIG. 2, and can move in the diagonally upper left direction in the original direction and can be separated from the charging member 9.

The cleaning member 10 and the support member 11 are
As shown in FIG. 1, the pair of springs 13 and 14 provided in the longitudinal direction of the support member 11 comes into contact with the charging member 9 by the spring force and extends in the longitudinal direction of the charging member 9. A cam member (not shown) separates from the charging member 9. In order to bring the cleaning member 10 into and out of contact with the charging member 9, appropriate driving means for driving the cam member can be used, and the description of the driving means is omitted here.

Similar to the brush shown in FIG. 4, the cleaning member 10 of this embodiment is composed of a large number of brush flock 10a, and each brush flock 10a is a brush flock 10a.
In a free state in which no load is applied to the holding member 11, the hair is implanted vertically upright with respect to the holding member 11. When the brush flocking 10a is vertically contacted with the member in the longitudinal direction, the brush flocking 10a has a falling tendency to easily fall in one direction, that is, the left direction as in the case shown in FIG. 4B. Then, in the image forming apparatus 1 of this example, as shown by a dotted line in FIG. The brush flocking 10a is set so that the falling direction B depending on the falling behavior is opposite to each other. In other words, the separation / contact direction A of the cleaning member 10
And the inclination direction of the falling direction B are set to be opposite to each other.

By providing the brush of the cleaning member 10 as described above, the cleaning member 10 moves obliquely downward and rightward to clean the charging member 9 as shown in FIG. When the contact is made in the direction A, as shown in FIG. 3 (b), the brush flock 10a of the cleaning member 10 receives the load in the contact direction A applied at the time of the contact, and furthermore, due to its falling habit.
The cleaning member 10 falls down in the falling direction B opposite to the contact direction A. When the brush flocking 10a falls in the falling direction B due to the load at the time of contact and the falling habit of the brush flocking 10a, the brush flocking 10a falls down smoothly without resistance. You will fall significantly.

Therefore, the contact of the brush flock 10a with the charging member 9 is substantially uniform over the entire axial direction of the charging member 9 and becomes stable. Thereby, the charging member 9
Can be uniformly cleaned. When the cleaning of the charging member 9 by the cleaning member 10 is completed,
The cleaning member 10 is separated from the charging member 9 in the original direction, that is, in the diagonally upper left direction. At this time, since the brush flock 10a has largely fallen in the falling direction B opposite to the separation direction A of the cleaning member 10, The elastic restoring force for returning has increased. For this reason, the brush flock 10a has such a large elastic restoring force, and even after cleaning, the toner still sticking to the charging member 9 is repelled, and the adhesive force of the toner to the charging member 9 is weakened. Then, the toner adheres to the charging member 9. in this way,
The toner adhering in a floating state to the charging member 9 is
Is moved toward the OPC 2 by the rotation of, and is attracted and attached to the OPC 2 to be easily removed from the charging member 9. Note that OP
The toner attached to C2 is removed by the cleaning device 7.

The developing device 5 includes yellow, magenta, cyan, and black developing devices 28, 29, 30, and 31, similarly to the developing device of the conventional full-color image forming apparatus. Containers 28, 29, 30, 31 are OPC
Are arranged along the outer circumference of the. In this case, the arrangement order of the developing units 28, 29, 30, 31 for each color is not limited to the above-mentioned order, but is arbitrarily set. In the following description, for convenience of description, the order of the above-described colors, that is, yellow, magenta, cyan, and black, in order of each developing unit 28,
It is assumed that 29, 30, 31 are provided.

The cleaning device 7 also includes a cleaner housing 32 and a cleaning blade 33 as in the conventional full-color image forming apparatus. In that case, the cleaner housing 32 is formed integrally with the frame 8a of the process cartridge 8 as shown. Note that the cleaner housing 32 may be formed separately from the frame 8 a of the process cartridge 8 and attached to the process cartridge 8.

As described above, in the image forming apparatus 1 of this embodiment, the OPC 2, the charging member 9, and the cleaning member 1 for the charging member 9 are provided.
0, the developing device 5 and the cleaning device 7 are accommodated in the frame 8a of one process cartridge 8 (note that FIG. 1 shows the developing device 5 and the cleaning device 7).
Are not accommodated in the frame 8a of the process cartridge 8, but these are also accommodated in the frame 8a of the process cartridge 8 in this example in the same manner as in the related art.)

The operation of the thus configured image forming apparatus 1 of this embodiment will be described. First, at normal times, the cleaning member 10 is set at the separated position shown in FIG. In forming an image, the surface of the OPC 2 is charged by the charging member 9 in the same manner as a conventional general image forming apparatus, and then the image is exposed as an electrostatic latent image on the charged portion of the OPC 2 by the exposure device 4. . And this OPC
2 is developed in order by yellow, magenta, cyan, and black developing units 28, 29, 30, and 31 to be visualized, and the developed image on the OPC 2 is transferred to the intermediate transfer device 6. Is transferred to a transfer device (not shown), color-matched by the transfer device, transferred to a transfer material (not shown), and then fixed by a fixing device (not shown), thereby transferring the image. A desired image can be obtained on the material.

After the developed image is transferred to the transfer material, the residual toner remaining on the OPC 2 is removed by the cleaning blade 33 of the cleaning device 7 and stored in the cleaner housing 32. Thus, the image forming apparatus 1 completes the image formation, and after the OPC 2 is neutralized, the OPC 2 is charged again by the charging member 9 for the next image formation, and the same image forming process is performed thereafter.

After the transfer, the residual toner remaining on the OPC 2 is
2 and is accommodated in the cleaner housing 32, but a part thereof is not removed, but passes through the cleaning blade 33 and moves toward the charging member 9, and adheres to the charging member 9. Become like Further, the toner scattered from the developing device during the image formation for a predetermined period may adhere to the charging member 9, or the scattered dust and dust around the OPC 2 may adhere to the charging member 9. For this reason, in the image forming apparatus 1 of this example, the cleaning process is periodically performed, and the foreign material attached to the charging member 9 is removed by the cleaning member 10.

In this cleaning step, the cleaning member 10 is first brought into contact with the charging member 9 as described above. In this state, the charging member 9 is rotated, and foreign matter such as toner attached to the charging member 9 is removed by the cleaning member 10. At this time, since the abutment of the brush flocking 10a on the charging member 9 is substantially uniform and stable over the entire axial direction of the charging member 9 as described above, the charging member 9 is uniformly cleaned. . The foreign matter such as toner removed by the cleaning member 10 is accommodated in the cleaner housing 32 in the process cartridge 8 or, when a housing portion is provided in the process cartridge 8 separately from the cleaner housing 32, the housing portion. Will be accommodated. When the charging member 9 is rotated for a predetermined time, the rotation of the charging member 9 is stopped, and the cleaning member 10 is moved in the original direction and separated from the charging member 9. When the cleaning member 10 is separated from the charging member 9, foreign substances such as toner stuck to the charging member 9 are repelled by the large elastic restoring force of the brush flock 10 a as described above, and the foreign substances are almost in a floating state. It comes to adhere to the charging member 9.
Thus, the step of cleaning the charging member 9 by the cleaning member 10 is completed. Thereafter, when the charging member 9 is rotated again, the foreign matter such as toner attached to the charging member 9 while floating is moved to the OPC 2 and removed from the charging member 10,
Further, the foreign matter that has moved to the OPC 2 is removed from the OPC 2 by the cleaning device 7.

According to the image forming apparatus 1 of this embodiment, the direction in which the brush is detached from the charging member 9 and the direction of the brush implantation 10a are effectively utilized by effectively utilizing the falling behavior of the brush implantation 10a of the brush used for the cleaning member 10. Falling direction B due to falling habit
Are set to be in opposite directions, so that each brush flock 10a of the brush can contact the charging member 9 almost uniformly and stably over the entire axial direction.
Therefore, the cleaning of the charging member 9 by the brush can be performed uniformly in the axial direction of the charging member 9 without uneven cleaning. When the brush is in contact with the charging member 9, the brush flocking 10 a has a large elastic restoring force. Therefore, when the brush is separated from the charging member 9, the elastic flocking of the brush flocking 10 a is performed. With force, foreign matter such as toner still sticking after cleaning is repelled, and the adhesive force of the foreign matter such as toner to the charging member 9 is weakened, so that the toner can be almost floated. Accordingly, foreign matters such as toner stuck to the charging member 9 can be more easily and more reliably removed.

Thus, the cleaning ability of the cleaning member 10 can be improved, and the cleaning of the charging member 9 can be performed more reliably and more sufficiently. Accordingly, it is possible to prevent the occurrence of uneven charging due to streaks on the surface of the charging member 9, to prevent deterioration of the image quality, and to further improve the image quality.

In the image forming apparatus 1 of the above-described example, the present invention is described as applied to a full-color image forming apparatus. However, the present invention is not limited to this. The present invention can be applied to any image forming apparatus as long as the image forming apparatus includes at least a charging member for charging the photoreceptor and a cleaning member for the charging member.

[0032]

As is apparent from the above description, according to the image forming apparatus of the present invention, the brush and the cleaning member are obliquely separated from each other in the axial and radial directions with respect to the charging member, and the brush flocking behavior is reduced. Is set in the opposite direction, so that the brush flock of the brush can contact the charging member almost uniformly and stably over the entire axial direction. Therefore, the cleaning of the charging member by the brush can be performed uniformly and uniformly in the axial direction of the charging member.

When the brush is in contact with the charging member, the brush flock has a large elastic restoring force. Therefore, when the brush separates from the charging member,
The brush flocking repels foreign substances such as toner which are still stuck after cleaning by the elastic restoring force, weakens the adhesive force of the foreign substances such as toner to the charging member, and makes the foreign substances such as toner almost float. As a result, foreign substances such as toner stuck to the charging member can be more easily and reliably removed.

Thus, the cleaning ability of the cleaning member can be improved, and the cleaning of the charging member can be performed more reliably and more sufficiently. Therefore, it is possible to prevent the occurrence of uneven charging due to streaks on the surface of the charging member, to prevent deterioration of the image quality, and to further improve the image quality.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a full-color intermediate transfer type image forming apparatus to which an example of an embodiment of the image forming apparatus of the present invention is applied.

FIG. 2 is a diagram schematically illustrating a relationship between a cleaning member and a charging member in this example.

FIG. 3 is a diagram illustrating a diagonally lower right direction in which the brush of the cleaning member of this example moves toward and away from the charging member, and a left direction in which brush flocking is likely to fall due to the falling habit.

FIG. 4 shows a brush used for a conventional cleaning member;
(A) is a diagram showing brush flocking in a free state, (b) is a diagram showing a state in which brush flocking has fallen to the left due to a falling habit,
(C) is a diagram showing a state in which the brush flocking has fallen rightward due to the falling habit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Photoconductor (OPC), 3 ... Charging device, 4 ... Exposure device, 5 ... Developing device, 6 ... Intermediate transfer device,
7 cleaning device, 8 process cartridge, 8
a: frame of process cartridge 8, 9: charging member, 1
0: cleaning member, 10a: brush flocking, 11: holding member,
13,14… Spring

Claims (1)

[Claims] 1. A photoconductor on which an electrostatic latent image is formed, a charging member that contacts the photoconductor and charges the photoconductor, and a charging member that is provided so as to be capable of separating from and contacting the charging member. An image forming apparatus including at least a cleaning member for cleaning, wherein the charging member is cleaned by rotating the charging member in a state where the cleaning member is in contact with the charging member. The member is formed of a brush composed of a large number of brush flocked brushes, and the brush flocked has a falling behavior of falling in one direction when a load is applied uniformly and vertically over the longitudinal direction of the brush in a free state, The direction of separation and contact of the cleaning member with respect to the charging member is set in an oblique direction in the axial direction and the radial direction of the charging member, and the falling direction of the cleaning member due to the falling of the brush flocking. An image forming apparatus characterized by being set in the disjunction direction opposite to the direction of the cleaning member.