JP2001042609A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure pressing force of a cleaning member at contacting of the cleaning member to an electrifying member with hardly any change due to passage of time by improving the durability of an elastic member by which the cleaning member is pressed to the electrifying member. SOLUTION: In this image forming device, a no-load state is produced, when a V shaped spring of the elastic member 12 is contained inside a recessed part of a no-load state setting means 13 in a separated position of the cleaning member 10 from the electrifying member 9. Furthermore, pressing force of the cleaning member 10 to the electrifying member 9 becomes maximum in a contact position of the cleaning member 10 to the electrifying member 9 and the pressing force that is sufficient to obtain a prescribed cleaning function is acquired. Durability of the elastic member 12 is improved by preventing the deterioration of elasticity of the elastic member 12 by setting the elastic member 12 with which the cleaning member 10 is pressed to the electrifying member 9 to the no-load state by the no load state setting means 13.

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 image forming apparatus belongs to the technical field of an image forming apparatus, and in particular, includes a cleaning member for a charging member for removing foreign matters such as toner adhered to the charging member of the charging device, and an image forming apparatus including an elastic member for pressing the cleaning member against the charging member. Belongs to the technical field of equipment.

[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.

For this reason, an image forming apparatus provided with a cleaning member for removing foreign substances such as toner adhered to the surface of a charging member has been disclosed in, for example, Japanese Patent No. 2853208 and Japanese Patent Application Laid-Open No. 07-128954. Proposed. If the cleaning member of these image forming apparatuses is constantly in contact with the charging member, the surface of the charging member will be damaged and charging failure will occur. 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 provided with the cleaning member, the surface of the charging member is cleaned, and the charging of the photoconductor is improved.

[0005]

Incidentally, in an image forming apparatus provided with such a cleaning member which can be separated from and brought into contact with the charging member, Japanese Patent No. 2853208 and Japanese Patent Application Laid-Open No. 07-128954 disclose. As described, in general, an elastic member such as a spring is often used for pressing the cleaning member against the charging member.

However, when the elastic member is used as described above, when the cleaning member is set to be separated from the charging member, the elastic member is compressed from a state where the cleaning member is in contact with the charging member. That is, a state where a load greater than the contact state is received is maintained. Moreover,
Generally, cleaning by the cleaning member is not so large, and in most cases, the cleaning member is set to be separated from the charging member, so that the elastic member is held for a long time under a large load. For this reason, the elastic member causes deterioration of elasticity and permanent deformation, and has a problem in durability. In addition, when the elastic member deteriorates in elasticity or causes permanent distortion as described above, when the cleaning member is brought into contact with the charging member to clean the charging member, a sufficient pressing force of the cleaning member against the charging member cannot be obtained. As a result, the cleaning ability is reduced, and poor charging of the photoconductor and image defects occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to improve the durability of an elastic member that presses a cleaning member against a charging member and to improve the durability of the cleaning member to the charging member. It is an object of the present invention to provide an image forming apparatus which can sufficiently secure the pressing force of the cleaning member at the time of contact without substantially changing over time.

[0008]

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. A cleaning member provided to be detachable from the charging member to clean the charging member, and a pressing member for pressing the cleaning member against the charging member when the cleaning member contacts the charging member. In an image forming apparatus including at least an elastic member, when the cleaning member is separated from the charging member, a no-load state setting unit that sets the elastic member to a no-load state is provided. Features.

The invention of claim 2 is characterized in that the no-load state setting means is provided in a housing for accommodating the charging member, and is constituted by a recess for accommodating the elastic member in a no-load state. And

[0010]

In the image forming apparatus according to the present invention, when the cleaning member is separated from the charging member, the elastic member for pressing the cleaning member against the charging member is set by the no-load state setting means. It is set to a no-load state where no load is received. Thereby, the elasticity of the elastic member is hardly deteriorated, and the durability of the elastic member is improved. In particular, since the cleaning of the charging member by the cleaning member is generally performed periodically, the cleaning member is set in a state of being separated from the charging member and is in a no-load state, so that the elasticity of the elastic member is more effectively reduced. Will be prevented.
Therefore, when the charging member is cleaned by the cleaning member, the pressing force of the cleaning member on the charging member is sufficiently secured for a long period of time, and the cleaning ability is not reduced.
It will be kept well for a long time. In particular, according to the second aspect of the present invention, since the no-load state setting means is constituted by the concave portion provided in the housing, the structure of the no-load state setting means is simplified.

[0011]

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 example of an embodiment of the image forming apparatus of the present invention is applied. As shown in FIG. 1, an 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. It has. Charging device 3,
The exposure device 4, the developing device 5, the intermediate transfer device 6, and the cleaning device 7 include an OPC as in the conventional image forming apparatus.
2 are arranged clockwise in the figure in these order.

As shown in FIGS. 1 and 2A to 2C, the charging device 3 contacts the OPC 2 and
A charging member 9 such as a charging roller rotatably supported by a housing 8 for charging the charging member 2, and a cleaning member 10 provided to be detachable from the charging member 9 and for cleaning the surface of the charging member 9. The holding member 11 that holds the cleaning member 10 and operates to separate and contact the cleaning member 10 with the charging member 3 is provided on the surface of the holding member 11 opposite to the side that holds the cleaning member 10. An elastic member 12 made of a V-shaped spring and a driving means (not shown) for moving the holding member 11 in the left-right direction in FIG. 2 to contact or separate the cleaning member 10 from or to the charging member 9 are provided. The elastic member 12 has one side of the V-shaped spring fixed to the holding member 11, and the other side of the V-shaped spring is in a free state.

In FIG. 1, the elastic member 12 for pressing the cleaning member 10 against the charging member is described as a coil spring. However, this is simply illustrated schematically in FIG. The image forming apparatus 1 of this example is only described.
In this embodiment, a V-shaped spring is used as the elastic member 12 as shown in FIG.

When the cleaning member 10 is separated from the charging member 9, the housing 8 is provided with a no-load state setting means 13 comprising a concave portion for bringing the elastic member 12 of the V-shaped spring into a free state, that is, a no-load state. Is provided. The right side surface 13a of the concave portion of the no-load state setting means 13 is a slope inclined downward and to the right.
Is set to be substantially the same as the inclination angle of the other side of the V-shaped spring.

A large recess 14 is formed in the housing 8 adjacent to the recess of the no-load state setting means 13, and a lower end of a portion of the housing 8 forming a left side wall 14a of the recess 14 is formed. , A protruding portion 8a protruding in the longitudinal direction is formed. Further, the holding member 11 is provided with a protruding portion 11a protruding into the concave portion 14 of the housing 8. The left side surface 11b of the protruding portion 11a facing the protruding portion 8a of the housing 8 is formed as a slant surface inclined downward and to the right.
Is set to be substantially the same as the inclination angle of the right side surface 13a of the concave portion.

2A, the holding member 11 separates the cleaning member 10 from the charging member 9 as shown in FIG. 2A, and moves the cleaning member 10 to the charging member 9 as shown in FIG.
And can be moved between the contact position and the contact position.
In the separated position, the upper surface 11c of the holding member 11 contacts the lower surface 8b of the housing 8, and the elastic member 12 is housed in the recess of the no-load state setting means 13.
In this state, the elastic member 12 is in a no-load state.

As soon as the holding member 11 is pulled from the separated position by the driving means (not shown) and moves in the direction of arrow A shown in FIG. 2A, the other side of the V-shaped spring of the elastic member 12 is immediately turned on. Contacts the right side surface 13a of the concave portion of the no-load state setting means 13. Further, when the holding member 11 moves in the direction of arrow A, the other side of the V-shaped spring of the elastic member 12 moves down along the right side surface 13a, so that the holding member 11 and the cleaning member 10 move down. As shown in FIG. 2B, the cleaning member 10 comes into contact with the charging member 9. In this state, the pressing force of the cleaning member 10 against the charging member 9 is not generated because the elastic member 12 is still in the no-load state. When the holding member 11 is moved from the separated position shown in FIG. 2A to the position shown in FIG.
The holding member 11 moves in a state where the left side surface 11b of the holding member a is always in contact with the tip of the protruding portion 8a of the housing 8.

When the holding member 11 further moves in the direction of arrow A, the left side surface 11b of the protrusion 11a is separated from the tip of the protrusion 8a, and the V-shaped spring of the elastic member 12 is gradually positioned on the lower surface 8b of the housing 8. I will be. Then, since the V-shaped spring is compressed by applying a load from the housing 8, the V-shaped spring generates a spring force. This V
Due to the spring force of the U-shaped spring, that is, the elastic force of the elastic member 12,
The cleaning member 10 is pressed by the charging member 9. Then, as the holding member 11 moves in the direction of arrow A, the elastic member 1
Since the load of No. 2 increases, the elastic force generated by the elastic member 12 also increases, and the pressing force of the cleaning member 10 against the charging member 9 also increases. Most of the elastic member 12 is the housing 8
When the holding member 11 is positioned on the lower surface 8b, the movement of the holding member 11 is stopped, and the cleaning member 10 shown in FIG. In this state, the charging member 9 of the cleaning member 10
The maximum pressing force is applied, and the pressing force is sufficient to obtain a predetermined cleaning ability.

When the cleaning of the charging member 9 by the cleaning member 10 is completed, the holding member 11 is moved by the driving means in the opposite direction (that is, leftward in the drawing). Then, the load on the elastic member 12 applied by the housing 8 gradually decreases, and as shown in FIG.
When most of the elastic member 12 is located in the concave portion of the no-load state setting means 13, the elastic member 12 can no longer receive a load from the housing 8 and enters a no-load state. In this state, the pressing force of the cleaning member 10 on the charging member 9 also disappears.
Further, the left side surface 11b of the protrusion 11a of the holding member 11 comes into contact with the tip of the protrusion 8a of the housing 8.

When the holding member 11 moves further to the left, the left side surface 11b of the protruding portion 11a is in contact with the tip of the protruding portion 8a, so that the holding member 11 is inclined leftward along the inclined surface of the left side surface 11b. It will move upward. For this reason,
The cleaning member 12 is separated from the charging member 9, and finally, when the upper surface 11 c of the holding member 11 contacts the lower surface 8 b of the housing 8, the movement of the holding member 11 to the left stops.
The cleaning member 10 shown in FIG. In this state, the elastic member 12 is completely accommodated in the recess of the no-load state setting means 13, and the elastic member 12 is in a no-load state.
The no-load state setting means 13 is the same as the above-mentioned Japanese Patent No. 2853.
In the image forming apparatus 1 using one process cartridge in which the photosensitive member 2 is accommodated as disclosed in Japanese Patent Publication No. 208, the charging member 9 and the cleaning member 10 are provided together with the process cartridge. As disclosed in JP-A-07-128954,
In the image forming apparatus 1 in which the cleaning member 10 is provided in the image forming apparatus main body, the cleaning member 10 is provided together with the image forming apparatus main body.

The developing device 5 includes yellow, magenta, cyan, and black developing devices 15, 16, 17, and 18, similarly to the developing device of the conventional full-color image forming apparatus. Vessels 15, 16, 17, 18 are OPC
Are arranged along the outer circumference of the. In this case, the arrangement order of the developing units 15, 16, 17, and 18 of each color is not limited to the above-mentioned order, but is arbitrarily set. In the following description, for convenience of explanation, the order of the above-described colors, that is, yellow, magenta, cyan, and black, in the order of each developing unit 15,
16, 17, and 18 are provided.

The cleaning device 7 also includes a cleaner housing 19 and a cleaning blade 20 as in a conventional full-color image forming apparatus. In this case, the cleaner housing 19 is formed integrally with the housing 8 of the charging device 3 as shown. Note that the cleaner housing 19 can be formed separately from the housing 8.

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. . Then, the electrostatic latent image on the OPC 2 is yellow, magenta, cyan,
Then, the developed images are sequentially developed by the respective developing units 15, 16, 17 and 18 to be visualized, and the developed image on the OPC 2 is sent to a transfer device (not shown) via the intermediate transfer device 6. After the color is adjusted by a transfer device and transferred to a transfer material (not shown), the image is fixed by a fixing device (not shown), so that a desired image can be obtained on the transfer 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 20 of the cleaning device 7 and stored in the cleaner housing 19. 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 19, but a part thereof is not removed, but passes through the cleaning blade 20 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 photoconductor 2 may adhere to the charging member 9. . For this reason, in the image forming apparatus 1 of this example, the foreign matter attached to the charging member 9 is periodically removed by the cleaning member 10.

In this cleaning step, first, the driving means is driven as described above, and the holding member 11 is moved in the direction A to be set at the contact position shown in FIG. Thus, the cleaning member 10 contacts the charging member 9 and presses the charging member 9 with a predetermined pressing force. In this state, the charging member 9 is rotated, and foreign matters adhering to the charging member 9 are removed by the cleaning member 10.
Removed by The foreign matter removed by the cleaning member 10 is accommodated in the cleaner housing 19 or, if a housing portion is provided separately from the cleaner housing 19, is housed in the housing portion. When the charging member 9 is rotated for a predetermined time, the charging member 9 is stopped, and thereafter, the driving unit is driven again, and the holding member 11 is moved in the direction opposite to the direction A, and FIG.
It is set to the separated position shown in FIG. As a result, the cleaning member 10 is separated from the charging member 9. At this time, the V-shaped spring of the elastic member 12 is accommodated in the recess of the no-load setting means 13, and the elastic member 12 is in a no-load state. Thus, the cleaning process is completed.

As described above, according to the image forming apparatus 1 of this embodiment, when the cleaning member 10 is separated from the charging member 9, the elastic member 12 that presses the cleaning member 10 against the charging member 9 applies a load. Since no load is applied, the elasticity of the elastic member 12 hardly deteriorates. In particular, since the cleaning of the charging member 9 by the cleaning member 10 is performed at regular intervals, the cleaning member 10 is almost set to be separated from the charging member 9.
2 can be more effectively prevented from deteriorating.
Therefore, when the charging member 9 is cleaned by the cleaning member 10, it is possible to secure a sufficient pressing force of the cleaning member 10 against the charging member 9 for a long period of time, and the cleaning member 10 is favorably held for a long period of time without lowering the cleaning ability. be able to. Further, in the image forming apparatus 1 of this example, since the no-load state setting means 13 is configured by the concave portion 13 provided in the housing 8, the structure of the no-load state setting means 13 is simplified.

The no-load state setting means 13 of the present invention
Other than the above-described recess, any structure can be used as long as the elastic member 12 is put in a no-load state when the cleaning member 10 is separated from the charging member 9. Further, in 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, and at least the photosensitive member, a charging member for charging the photosensitive member, The present invention can be applied to any image forming apparatus provided that the image forming apparatus includes a cleaning member for the charging member.

[0029]

As is apparent from the above description, according to the image forming apparatus of the present invention, when the cleaning member is separated from the charging member, the cleaning member is set by the no-load state setting means. Since the elastic member that presses the elastic member is set in a no-load state in which no load is applied, it is possible to prevent the elasticity of the elastic member from deteriorating. Thereby, the durability of the elastic member can be improved. In particular, since the cleaning of the charging member by the cleaning member is generally performed regularly, the cleaning member is set in a state of being separated from the charging member and is in a no-load state, so that the elasticity of the elastic member is more effectively reduced. Can be prevented. Therefore, when the charging member is cleaned by the cleaning member, the pressing force of the cleaning member to the charging member can be sufficiently secured for a long period of time, and the cleaning member can be favorably held for a long period of time without lowering the cleaning ability. become. This makes it possible to prevent poor charging and image defects for a long period of time. According to the second aspect of the present invention, in addition to this, since the no-load state setting means is constituted by the concave portion provided in the housing, the structure of the no-load state setting means can be simplified.

[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 shows a cleaning member for a charging member used in the image forming apparatus shown in FIG. 1 and explains its operation;
(A) is a diagram schematically showing a state in which the cleaning member is separated from the charging member, (b) is a diagram schematically showing a cleaning member in a contact operation or a separation operation with the charging member, and (c) is a diagram schematically showing FIG. 4 is a diagram illustrating a contact state in which a cleaning member is in contact with a charging member with a predetermined pressing force.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Photoconductor (OPC), 3 ... Charging device, 5 ... Developing device, 7 ... Cleaning device, 8 ... Housing, 9 ... Charging member, 10 ... Cleaning member, 11 ... Holding member, 12 ... Elastic member, 13: no-load state setting means

Claims (2)

[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 comprising: a cleaning member to be cleaned; and an elastic member configured to press the cleaning member against the charging member when the cleaning member contacts the charging member. When it is separated from the member,
An image forming apparatus comprising: a no-load state setting unit that sets the elastic member to a no-load state. 2. The apparatus according to claim 1, wherein the no-load state setting unit is provided in a housing that houses the charging member, and is configured by a concave portion that houses the elastic member in a no-load state. Image forming device.