JP4953617B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus having a cleaning device that cleans an object to be cleaned with a cleaning blade.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a facsimile machine, or a printer, an electrostatic latent image is formed on a photosensitive member, and the electrostatic latent image is visualized as a toner image. Then, there is known a technique in which the toner image is transferred to an intermediate transfer member, and then the toner image on the intermediate transfer member is transferred to a recording medium such as plain paper. In this type of image forming apparatus, toner that has not contributed to the transfer remains on the photosensitive member or intermediate transfer member after transfer of the toner image, and is removed and collected. A cleaning device using a cleaning blade made of an elastic material is known as a cleaning device for cleaning the surface of a member to be cleaned such as a photosensitive member or an intermediate transfer member.

  In this type of cleaning device, a conductive component made of metal is generally used as a blade support member that supports the cleaning blade because it requires strength to hold the cleaning blade. If the conductive component is not grounded and is charged when the apparatus is driven, noise is generated and the image forming apparatus malfunctions. Therefore, it is considered to ground the cleaning device. On the other hand, the cleaning device has a shorter lifetime than the photosensitive member and the intermediate transfer member, and therefore needs to be grounded in a state where it can be detached and attached alone.

  Therefore, for example, a method has been proposed in which a blade spring provided on the image forming apparatus main body side and grounded is pressed against a blade support member of a cleaning device. According to this method, the cleaning device can be grounded without deteriorating the detachability of the cleaning device. However, in this method, the contact pressure of the leaf spring to the blade support member may affect the blade pressure applied to the object to be cleaned.

  The present invention has been made in view of the above problems. The object is to provide a cleaning device that can be grounded without impairing the detachability of the cleaning device and without affecting the pressure applied by the cleaning blade to the object to be cleaned, and an image forming apparatus using the same. Is to provide.

In order to achieve the above object, the invention according to claim 1 is an image forming apparatus having a cleaning device provided with a cleaning blade that pressurizes and contacts the object to be cleaned to remove toner remaining on the object to be cleaned. The object to be cleaned is configured as an endless belt , and is supported by a plurality of support rollers including a tension roller in which a biasing force toward the outside of the belt is applied to the bearing member in order to give a constant tension to the belt, the cleaning blade is disposed opposite to the Kahari roller across the該被cleaning body, at least one of the support shaft of the cleaning blade has a conductivity, the cleaning device is a support shaft having conductivity The grounding conductive member is grounded by contacting a grounding conductive member provided on the image forming apparatus main body side and grounded. The Kahari roller is supporting to the bearing member, the shaft receiving member is formed of an elastic member so as to maintain contact with the body-side conductive member provided in the image forming apparatus main body even if displaced, the upper Symbol The force F1 applied to the bearing member by elastic deformation of the grounding conductive member is configured such that F1 · cos θ and F2 are in the same direction when acting on the biasing force F2 at an angle θ. It is characterized by.
According to a second aspect of the present invention, in the image forming apparatus having a cleaning device provided with a cleaning blade that pressurizes and contacts the member to be cleaned and removes toner remaining on the member to be cleaned, the member to be cleaned is an endless belt. In order to give a constant tension to the belt, the belt is supported by a plurality of support rollers including a tension roller in which an urging force toward the outside of the belt is applied to the bearing member. disposed opposite to the Kahari roller across at least one of the support shaft of the cleaning blade has a conductivity, the cleaning device, the support shaft having conductivity is provided in the image forming apparatus main body and is grounded by contact with the grounding conductive member is grounded, the grounding conductive member, the bearing of the Kahari roller Is supported by the timber, made of an elastic member as the shaft receiving member can maintain contact with the body-side conductive member provided in the image forming apparatus main body even if displaced, the elastic deformation of the grounding conductive member When the force F1 applied to the bearing member is applied to the urging force F2 at an angle θ, the direction of F1 · cosθ is different from the direction of F2 , and the magnitude of F1 · cosθ is the magnitude of F2. It is comprised so that it may become smaller than this.
The invention according to claim 3, in the image forming apparatus according to claim 2, the force due to elastic deformation of the grounding conductive member F1 when acting at an angle θ with respect to the urging force F2, F1 · cos [theta] <0.1 · F2 is satisfied.
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the conductive support shaft is made of a conductive resin.
According to the present invention, since at least one of the support shafts of the cleaning blade has conductivity, it is possible to ground the support shaft. Even if the cleaning blade is grounded from the support shaft, the pressure applied to the object to be cleaned by the cleaning blade is not affected. Further, if the cleaning blade is grounded by bringing the shaft of the cleaning blade into contact with the grounded conductive member provided on the image forming apparatus main body side, the detachability of the cleaning device may be impaired. Absent.

  According to the present invention, there is provided a cleaning device capable of being grounded without impairing the detachability of the cleaning device and without affecting the pressure applied by the cleaning blade to the object to be cleaned, and an image forming apparatus using the same. There is an excellent effect that it can be provided.

  An embodiment in which the present invention is applied to a copying machine as an image forming apparatus will be described below. FIG. 1 is a configuration diagram showing an internal configuration of a copying machine adopting a so-called tandem type indirect transfer system. As shown in FIG. 1, in this copying machine, a drum-shaped photoreceptor 1 (1a, 1b, 1c, 1d) is disposed at the center so as to be rotatable in the direction of the arrow. Around the photosensitive member 1, there are a static eliminating device 2 for neutralizing the surface of the photosensitive member 1, a charging device 3 for uniformly charging the surface of the photosensitive member 1, and a charged portion of the photosensitive member 1 by performing optical writing with a laser beam. In addition, an exposure device 4 for forming an electrostatic latent image and a developing device 5 for developing the electrostatic latent image are provided. A cleaning device 6 for cleaning the surface of the photoconductor 1 after transfer is disposed around the photoconductor 1. This copier employs a so-called tandem system using four photoconductors 1, and the image forming component configuration provided around each photoconductor 1 is a color material (toner) handled by the developing device 6. ) Are the same except that they are different in color (the same components are denoted by the same reference numerals and description thereof is omitted).

  An intermediate transfer unit 10 is provided above the photoreceptor 1. FIG. 2 is a configuration diagram showing a schematic configuration of the intermediate transfer unit. As shown in FIG. 2, in the intermediate transfer unit 10, the intermediate transfer belt 11, which is a member to be cleaned, is wound around the tension roller 12, the drive roller 13, and the support rollers 14, 15 and rotated counterclockwise in the drawing. The The intermediate transfer belt 11 has a multilayer structure, and the base layer is made of, for example, a fluororesin, PVD sheet, or polyimide resin with little elongation, and the surface is covered with a smooth coat layer such as a fluororesin. Further, transfer rollers 16 for transferring a toner image formed on the photoconductor 1 to the intermediate transfer belt 11 are disposed at positions facing the photoconductor 1 with the intermediate transfer belt 11 interposed therebetween. Further, on the left side of the tension roller 12, an intermediate transfer belt cleaning device 20 for removing residual toner remaining on the intermediate transfer belt 11 after transfer by a secondary transfer device 20 described later is disposed. The tension roller 12 has a function of applying a constant tension to the intermediate transfer belt 11 and also serves as a cleaning counter roller. Since the cleaning device 20 has a shorter life than the intermediate transfer member 11, it can be detached independently as will be described later.

  A secondary transfer device 30 is disposed at a position facing the support roller 14 with the intermediate transfer belt 11 in between. In the secondary transfer device 30, the secondary transfer belt 31 is stretched between the support rollers 32, 33, 34, and 35 and is driven to rotate clockwise in the drawing, and is pressed against the support roller 14 via the intermediate transfer body 11. The image on the intermediate transfer belt 11 is transferred to the recording paper P. Some secondary transfer devices use a secondary transfer roller. Further, on the left side of the secondary transfer device 30, a secondary transfer belt cleaning device 36 that removes toner and the like remaining on the secondary transfer belt 31 after image transfer is provided.

  The recording paper P is stored in the lower paper feeding cassettes 40a and 40b in the drawing, and the uppermost recording paper P is conveyed by the paper feeding roller 41 to the registration roller pair 43 via the paper feeding path 42 one by one. . On the secondary transfer device 30, a fixing device 50 that fixes a transfer image on the recording paper P, a paper discharge guide pair 51, a paper discharge roller pair 52, and a paper discharge stack unit 53 are disposed. The fixing device 50 is configured by pressing a pressure roller against a fixing roller. Note that the secondary transfer device 30 described above also has a sheet conveyance function for conveying the recording paper P after image transfer to the fixing device 50. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer device 30. In such a case, it is difficult to provide this sheet conveyance function together.

  In the copying machine having the above configuration, when a start switch (not shown) is pressed, the drive roller 13 is rotationally driven by a drive motor (not shown) and the other rollers 12, 14, and 15 are driven to rotate, and the intermediate transfer body 11 is rotated and conveyed. To do. At the same time, the photosensitive member 1 is rotated by individual image forming means to form black, yellow, magenta, and cyan single-color images on each photosensitive member 1, respectively. Then, along with the conveyance of the intermediate transfer belt 11, these single color images are sequentially transferred to form a composite color image on the intermediate transfer belt 11. On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 41 is selectively rotated, and the recording paper P is fed out one by one from one of the paper feed cassettes 40 and put into the paper feed path 42. Stop at 43. Then, the registration roller pair 43 is rotated in synchronization with the composite color image on the intermediate transfer belt 11, and the recording paper P is sent between the intermediate transfer belt 11 and the secondary transfer device 30. Transfer and record a color image on the recording paper P. After the image transfer, the recording paper P is conveyed by the secondary transfer device 30 and sent to the fixing device 50. The fixing device 50 applies heat and pressure to fix the transferred image, and then passes through the paper discharge guide pair 51. The paper is discharged by the discharge roller 52 and stacked on the paper discharge tray 53. On the other hand, the intermediate transfer belt 11 after image transfer is freed of residual toner remaining on the intermediate transfer belt 11 after the image is transferred by the intermediate transfer belt cleaning device 20, and is prepared for re-image formation by the tandem image forming apparatus. Further, the secondary transfer belt 21 after the image transfer is removed by the secondary transfer belt cleaning device 30 to remove residual toner remaining on the secondary transfer belt 11 after the image transfer.

  Next, the intermediate transfer belt cleaning device 20 that is a characteristic part of the copying machine according to the present embodiment will be described. FIG. 3 is a configuration diagram showing a schematic configuration of the intermediate transfer belt cleaning device 20. As shown in FIG. 3, the intermediate transfer belt cleaning device 20 includes a cleaning blade 21 as a cleaning member. One end of the cleaning blade 21 is attached to a bracket 23 that is urged by a urging means (not shown), and the other end (free end) is in pressure contact with the intermediate transfer belt 11. The bracket 23 is made of a metal material because it needs strength to support the cleaning blade 21, and is held by a support shaft 24 attached from the outside of the cleaning device 25. The tension roller 12 acts as a cleaning counter roller, and applies tension to the intermediate transfer belt 11 by a belt tensioning spring 17.

FIG. 4 is a perspective view for explaining a grounding method of the intermediate transfer belt cleaning device. As shown in FIG. 4, in the intermediate transfer belt cleaning device 20, the support shaft 24 provided on the front side in the mounting direction to the apparatus main body (downstream side in the mounting direction) is made of a conductive material. On the other hand, on the apparatus main body side, a leaf spring 18 is provided which is supported by the bearing 12a of the tension roller 12 and whose tip is grounded via an upper guide plate 19 attached to the main body side conductive member, for example, the intermediate transfer belt 11. It has been. When the intermediate transfer belt cleaning device 20 is mounted on the apparatus main body, the contact surface 24 a of the support shaft 24 of the cleaning blade 21 and the protrusion 18 a of the leaf spring 18 come into contact with each other, so that the intermediate transfer belt cleaning device 20 will be grounded. Since the intermediate transfer belt 11 is grounded via the upper guide plate 19, the ground of the intermediate transfer belt cleaning device 20 is also grounded along this route.

  Here, the conductive support shaft 24 of the cleaning blade 21 has a flat contact surface 24a at the tip so that the contact area with the protrusion 18a of the leaf spring 18 becomes large. In consideration of contact with the leaf spring 18 and interference with other components, the support shaft 24 is preferably made of a conductive resin so that it can be easily formed even in a complicated shape. Further, by providing the conductive support shaft 24 on the front side in the mounting direction, the plate spring 18 provided on the back side (the side opposite to the opening side) of the main body of the image forming apparatus is brought into contact with the ground. Therefore, the detachability of the intermediate transfer belt cleaning device 20 is not impaired. Further, even when the intermediate transfer belt cleaning device 20 is removed, the leaf spring 18 is not exposed in the intermediate transfer belt cleaning device 20 and does not touch the user's hand, which is excellent in safety. The other support shaft (not shown) of the cleaning blade 21, that is, the support shaft on the rear side in the mounting direction (upstream side in the mounting direction) is not necessarily grounded and therefore does not necessarily have conductivity.

In the intermediate transfer unit 10, when the tension roller 12 changes, the cleaning blade 21 also changes accordingly. However, since the leaf spring 18 is supported by the bearing 12a of the tension roller 12 and incorporated in the fluctuating system, contact failure between the leaf spring 18 and the support shaft 24 due to the variation of the tension roller 12 can be prevented. . Further, if the force that the plate spring 18 receives by contact with the upper guide plate 19 is F1, this plate spring pressing force F1 may be taken from the belt tension F2 of the belt tensioning pull 17. In Figure 4, angle θ tilt with respect to the direction in which the direction of the plate spring pressing force F1 acts belt pressurizing tension F2, although the plate spring pressing force F1 and the belt pressing tension F2 are described canceled orientation, F1 It is preferable that cos θ and F2 are in the same direction. As a result, when the intermediate transfer belt cleaning device 20 is grounded, a portion other than the leaf spring 18 that connects the support shaft 24 and the belt tension spring 17 is unnecessary, which leads to cost reduction. In addition, since no force other than the belt tension F 2 acts on the belt tension spring 17, a stable belt tension can be applied to the intermediate transfer belt 11. In particular, the only belt Kahari spring 17 is effective when that can not be pressurized Zhang intermediate transfer belt 11.

On the other hand, the constraints on the shape and the space of each part, even if the orientation of the pressing force F1 as shown in FIG. 4 was acting to be different from the orientation of the belt pressurizing tension F2, the pressing force F1 · cos [theta] is the belt pressing If it is sufficiently smaller than the tension F2, it can be used without any problem. Even if the belt tensioning spring 17 contracts slightly, contact failure between the leaf spring 18 and the upper guide plate 19 can be prevented. Specifically, since the tolerance of the spring pressure is usually 10%, if the direction of the leaf spring pressing force F1 is inclined by an angle θ with respect to the direction in which the belt tension F2 acts, F1 · cos θ <0. .1 · F2 should be set. It can be determined that the leaf spring pressing force F1 is negligibly small compared to the belt tension F2.

As described above, according to the intermediate transfer belt cleaning device 20 according to the present embodiment, since the support shaft 24 of the cleaning blade 21 has conductivity, it is possible to ground the support shaft 24. The target of grounding is a bracket 23 made mainly of metal. However, if the leaf spring 18 is brought into direct contact with the bracket 23, the pressure of the cleaning blade 21 may be affected. On the other hand, if the ground is taken from the support shaft 24 of the cleaning blade 21, the pressurization of the cleaning blade 21 is not affected.
Further, according to the intermediate transfer belt cleaning device 20 according to the present embodiment, the support shaft 24 is made of a conductive material. Therefore, even if the support shaft 24 has a complicated shape in consideration of contact with the leaf spring 18 which is a conductive biasing member for grounding, interference with other parts, etc., it can be easily made. .
Further, according to the copying machine according to the present embodiment, the intermediate transfer belt cleaning device is brought into contact with the conductive support shaft 24 of the intermediate transfer belt cleaning device 20 and the grounded plate spring 18 on the apparatus main body side. There are 20 grounds. According to such a configuration, the detachability of the intermediate transfer belt cleaning device 20 is not impaired. In addition, even when the intermediate transfer belt cleaning device 20 is removed, the leaf spring is not exposed and the safety is excellent.
In the copying machine according to the present embodiment, the plate spring 18 is supported by the bearing 12a of the tension roller 12 that is a tension roller. Therefore, contact failure between the leaf spring 18 and the support shaft 24 due to fluctuation of the tension roller 12 can be prevented.
Further, according to the copier according to the present embodiment, the urging force of the leaf spring 18, that is, the leaf spring pressing force F1, is a part of the belt tension F2 of the tension roller 12. For this reason, when the intermediate transfer belt cleaning device 20 is grounded, other than the leaf spring 18 that connects the leaf spring 18 and the belt tensioning spring 17 is not necessary, leading to cost reduction. Further, since no force other than the belt tension F2 acts on the belt tensioning spring 17, a stable tension can be applied to the intermediate transfer belt 11.
Further, according to the copying machine according to the present embodiment, if the leaf spring pressing force F1 acts in a direction different from the belt tension F2, the belt tension spring 17 is very small as long as the belt tension F2 is small. It is possible to prevent a contact failure between the leaf spring 18 and the support shaft 24 against an excessive shrinkage.
Further, according to the copier according to the present embodiment, if the leaf spring pressing force F1 is smaller than the spring tolerance of the belt tensioning spring 17, the magnitude of the leaf spring pressing force F1 is compared with the belt tension F2. It can be judged that it is so small that it can be ignored.

  In the cleaning device according to the present embodiment, the intermediate transfer belt cleaning device 20 of the intermediate transfer unit 10 has been described, but the present invention is not necessarily limited thereto. For example, the present invention may be applied to a cleaning device for a photoreceptor that is an image carrier. Further, the case where the object to be cleaned is applied to the endless belt-shaped intermediate transfer belt 11 has been described. However, for example, a drum-shaped object to be cleaned may be used.

1 is a configuration diagram showing an internal configuration of a copier according to an embodiment. FIG. 2 is a configuration diagram showing a configuration of an intermediate transfer unit of the copier. FIG. 3 is a configuration diagram showing a configuration of an intermediate transfer belt cleaning device of the intermediate transfer unit. FIG. 6 is a perspective view for explaining a grounding method of the intermediate transfer belt cleaning device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 10 Intermediate transfer unit 11 Intermediate transfer belt 12 Tension roller 17 Belt tension spring 18 Leaf spring 19 Upper guide plate 20 Intermediate transfer belt cleaning device 21 Cleaning blade 23 Bracket 24 Support shaft

Claims (4)

In an image forming apparatus having a cleaning device provided with a cleaning blade that contacts a member to be cleaned under pressure and removes toner remaining on the member to be cleaned.
The object to be cleaned is configured as an endless belt , and is supported by a plurality of support rollers including a tension roller in which a biasing force toward the outside of the belt is applied to the bearing member in order to give a constant tension to the belt,
The cleaning blade is disposed opposite to the Kahari roller across the該被cleaning member,
At least one of the support shafts of the cleaning blade has conductivity,
The cleaning device is grounded by contacting a grounded conductive member having a conductive support shaft provided on the image forming apparatus main body side and grounded,
It said grounding conductive member is supported by the bearing member of the Kahari roller, as the shaft receiving member can maintain contact with the body-side conductive member provided in the image forming apparatus main body be displaced is formed of an elastic member, a force F1 to the elastic deformation of the upper Symbol grounding conductive member provided to the bearing member, when acting at an angle θ with respect to the urging force F2, each other and F1 · cos [theta] and F2 An image forming apparatus configured to be in the same direction . In an image forming apparatus having a cleaning device provided with a cleaning blade that contacts a member to be cleaned under pressure and removes toner remaining on the member to be cleaned.
The object to be cleaned is configured as an endless belt , and is supported by a plurality of support rollers including a tension roller in which a biasing force toward the outside of the belt is applied to the bearing member in order to give a constant tension to the belt,
The cleaning blade is disposed opposite to the Kahari roller across the該被cleaning member,
At least one of the support shafts of the cleaning blade has conductivity,
The cleaning device is grounded by contacting a grounded conductive member having a conductive support shaft provided on the image forming apparatus main body side and grounded,
It said grounding conductive member is supported by the bearing member of the Kahari roller, as the shaft receiving member can maintain contact with the body-side conductive member provided in the image forming apparatus main body be displaced The force F1 formed by the elastic member and applied to the bearing member by the elastic deformation of the grounding conductive member acts on the biasing force F2 at an angle θ, and the direction of F1 · cos θ is the direction of F2. And an image forming apparatus characterized in that the size of F1 · cos θ is smaller than the size of F2 . The image forming apparatus according to claim 2.
Force F1 applied to the bearing member by the elastic deformation of the grounding conductive member, when acting at an angle θ with respect to the urging force F2, to satisfy the relationship F1 · cosθ <0.1 · F2 An image forming apparatus. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus, wherein the conductive support shaft is made of a conductive resin.

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