JP5338055B2 - Charging device, process cartridge, image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a charging device, a process cartridge including the charging device, an electrophotographic copying apparatus including the charging device, a facsimile, a laser beam printer, a plotter, a multifunction peripheral, and a printing apparatus.

  2. Description of the Related Art Conventionally, as a charging device used in an image forming apparatus such as a copying machine, a charging roller device that is charged in contact with a surface to be charged is known, and this contact-type charging roller device does not generate abnormal images over a long period of time. Thus, a charging roller cleaner contact / separation method has been devised (see, for example, Patent Document 1). However, in the contact-type charging roller device, the foreign matter adhering to the charging roller comes into contact with and adheres to the surface of the charging roller.

In recent years, therefore, a proximity charging roller device has been devised in which a charging roller is disposed in close proximity to a surface to be charged in a non-contact state, and has a configuration in which foreign matter hardly adheres to the charging roller. However, even in this proximity charging roller device, due to long-term use (durability), components such as external additives such as silica contained in the transfer residual toner and the filling amount contained in the transfer paper are electrically applied to the surface of the charging member. Alternatively, it adheres mechanically, and local unevenness occurs in the impedance of the gap between the charging member and the image carrier, and this finally appears as image unevenness. In particular, the humidity of the use environment, deposits by wet moisture or de, unevenness in impedance is increased in length, image unevenness becomes conspicuous. There is also a disclosure of a cleaning method that takes advantage of the non-contact charging roller method (small adhesion of foreign matter).

However, as described above, the influence on the charging roller dirt is very large,
In the configuration in which the charging roller and the cleaning roller are integrally attached and detached, when the cleaning roller is replaced due to the end of its service life, the charging roller is soiled with toner accumulated on the cleaning roller or dirt on the operator's hands. The charging roller that can still be used becomes unusable due to the dirt.

JP-A-7-128956

  The present invention has been made under the circumstances described above. When the charging roller is attached or detached, the charging roller is soiled with toner accumulated on the roller-shaped cleaning member or dirt on the operator's hand, and a charging roller that can still be used is also provided. It is an object of the present invention to solve the problem that it becomes impossible to use due to the dirt.

In order to achieve the above object, the invention according to claim 1 is a charging device for charging an endlessly movable image carrier,
The charging roller includes a charging roller, a supporting member that supports the charging roller, and a roller-shaped cleaning member that cleans the charging roller. The charging roller is slidably fitted to a shaft portion of the roller-shaped cleaning member, and the charging roller provided an open guide groove toward the shaft center, the roller-shaped cleaning member with respect to the charging roller, the charging apparatus detachably configured solely along the opening guide groove,
It was to have the rotating arm Before moving the shaft portion of the roller-shaped cleaning member to the open guide groove to hold the shaft from the outside of the open guide grooves of the roller-shaped cleaning member.
According to a second aspect of the present invention, in the charging device according to the first aspect, the charging roller is configured to be detachable independently from the roller-shaped cleaning member.
The invention according to claim 3 is the charging device according to claim 1 or 2 ,
Was the depth of the guide grooves is set so that both rollers can be circumscribed in a state where the shaft portion is fitted before Symbol open guide groove to the roller-shaped cleaning member.
According to a fourth aspect of the present invention, there is provided the charging device according to any one of the first to third aspects, wherein the roller-shaped cleaning member is attached to or detached from the charging roller in a state viewed from the longitudinal direction of the charging roller. In the region opposite to the side on which the charging roller is disposed with the common tangent line as a boundary, and the direction is within a range of 180 degrees centering on the contact point of both rollers.
According to a fifth aspect of the present invention, in the charging device according to any one of the first to fourth aspects, the support member that supports the charging roller and the support member that supports the roller-shaped cleaning member are integrally configured. It was decided.
According to a sixth aspect of the present invention, in the charging device according to any one of the first to fourth aspects, the roller-shaped cleaning member can be brought into contact with and separated from the charging roller.
According to a seventh aspect of the present invention, in the charging device according to any one of the first to sixth aspects, the surface of the roller-shaped cleaning member is a porous material (foam) .
The invention according to 請 Motomeko 8 is the charging device according to any one of claims 1 to 7, wherein the roller-shaped cleaning member surface porous material with a porous material (foam) was the melamine foam .
According to a ninth aspect of the present invention, there is provided a process cartridge which integrally supports an image carrier and at least one means selected from a charging device, a developing device, and a cleaning device, and is detachable from an image forming apparatus main body. The charging device is the charging device according to any one of claims 1 to 8.
According to a tenth aspect of the present invention, in the image forming apparatus having the charging device, the charging device is the charging device according to any one of the first to ninth aspects.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, the charging roller and the roller-shaped cleaning member are configured to be detachable separately, and the mounting direction of the roller-shaped cleaning member is detachable. And the contact direction of the image bearing member of the charging roller with a difference of 90 degrees or more.

According to the present invention, the roller-shaped cleaning member that may contaminate the charging roller is accurately and stably operated by mechanical means, and toner accumulated on the roller-shaped cleaning member, dirt on the operator's hand, etc. in soil the charging roller was Mau problem is solved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[1] Outline of Image Forming Apparatus In FIG. 1, a charging device 2, a developing device 6, and a photoconductor 1 as an endlessly movable image carrier are arranged in the order of rotation of the photoconductor 1 as indicated by an arrow A. A transfer separation device 7 and a cleaning device 8 are arranged. An exposure device 9 is positioned between the charging device 2 and the developing device 6, and a registration roller pair 10 is positioned between the developing device 6 and the transfer separation device 7.

  The charging device 2 is provided with a charging roller 3 disposed close to the surface to be charged of the photosensitive member 1 and a roller-like cleaning member 4 that rotates in contact with the charging roller 3 and removes deposits on the surface. ing.

  When forming an image, light from the exposure device 9 is incident on the surface of the photosensitive member 1, and the charged surface uniformly charged by the charging roller 3 is exposed to form an electrostatic latent image thereon. Is developed with toner supplied by the developing sleeve 6a of the developing device 6 to form a toner image.

  On the other hand, the sheet-like medium P in the paper feed cassette (not shown) is fed one by one by a rotating paper feed roller at a predetermined timing, and is temporarily stopped by the registration roller pair 10 and then subjected to timing adjustment. At a timing coincident with the toner image on the body 1, the toner image is conveyed toward a transfer portion where the transfer separation device 7 is provided.

  The sheet-like medium P is transferred with a toner image on the upper surface side, separated from the photoreceptor 1 and conveyed to a fixing device (not shown), where the toner is fixed and then discharged to a paper discharge tray. On the other hand, foreign matters such as toner and paper dust remaining on the photosensitive member 1 after the transfer are removed by a cleaning blade 8a provided in the cleaning device 8, and the potential remaining on the photosensitive member 1 is removed by a static elimination lamp. The next charging roller 2 prepares for charging.

[2] Charging Device FIG. 2 shows a configuration around the charging roller and the roller-shaped cleaning member. The charging roller 3 and the roller-shaped cleaning member 4 are simultaneously supported by a support member 5 that supports the charging roller 3 and the roller-shaped cleaning member 4.

  By doing so, since the positional relationship between the charging roller 3 and the roller-shaped cleaning member 4 is determined by one member, the position can be easily and accurately regulated. The roller cleaning member 4 is also supported by the rotating arm 11. The operation configuration of the rotating arm 11 will be described later.

  As shown in FIG. 3, the charging roller 3 and the roller-like cleaning member 4 are supported by a support member 5. The support member 5 is a charging frame 12 indicated by a two-dot chain line, and a roller-like cleaning member cover 13 indicated by a broken line. Is supported by. The charging device 2 includes the charging roller 3, the roller-like cleaning member 4, the support member 5, the charging frame 12, the roller-like cleaning member cover 13, and the like. The charging device 2 is detachably attached directly to the image forming apparatus main body, or is attached to the image forming apparatus main body via a process cartridge.

4 and 5, a substantially U-shaped groove 5a that opens downward is formed in the support member 5, and a bearing 3a that supports the core metal 3b of the charging roller 3 is fitted in the groove 5a. Is retained.
The opening of the groove 5a is formed slightly narrower than the outer diameter of the bearing 3a, and prevents the charging roller 3 from dropping from the groove 5a due to its own weight.

  The attaching / detaching direction of the charging roller 3 with respect to the support member 5 is a downward direction indicated by an arrow Q with the center O3 of the charging roller 3 as a base point in the figure. The gold 3b can pass through the opening of the groove 5a and can be removed downward.

  On the other hand, on the upper left side of the charging roller 3 held by the support member 5, the roller-like cleaning member 4 is guided and fitted into the open guide groove 5 b formed in the support member 5. Thus, the charging roller 3 supported by the support member 5 is circumscribed by its own weight. The depth of the open guide groove is set so as to enable contact by the dead weight.

  Since the open guide groove 5b has a groove width that allows the metal core 4a to slide, and is open to the outside, the roller-shaped cleaning member 4 can be removed from the support member 5 along the open guide groove 5b. The attachment / detachment direction of the roller-shaped cleaning member 4 with respect to the support member 5 is the direction of the open guide groove 5b, and is an obliquely upper left direction indicated by an arrow R with the center O4 of the roller-shaped cleaning member 4 as a base point.

  In this way, the charging roller 3 and the roller-shaped cleaning member 4 are configured to be detachable from the support member 5 separately. With this configuration, when the roller-like cleaning member 4 is to be replaced due to its life, it becomes difficult to cause a problem that the charging roller is soiled with toner accumulated on the roller-like cleaning member 4 or dirt on the operator's hand. The charging roller 3 after replacement of the cleaning member 4 can also be used stably. In addition, since the charging roller 3 can also be removed independently, the charging roller 3 is more likely to be contaminated with toner accumulated on the roller-like cleaning member 4 or dirt on the operator's hands than when the supporting member 5 is removed from the apparatus main body together. It becomes difficult to cause a problem that stains the surface.

  The attachment / detachment direction of the charging roller 3 indicated by the arrow Q is also a contact direction with respect to the photoreceptor 1. Here, when an auxiliary line S passing through the center O3 and having an angle of 90 degrees with respect to the arrow Q is drawn, an angle range of 90 degrees in which the roller-shaped cleaning member 4 is sandwiched between the arrow Q and the auxiliary line S is assumed. When the position is set at, the outer peripheral portion of the charging roller 3 is rubbed against the roller-shaped cleaning member 4 when the charging roller 3 is attached or detached alone.

  In order to avoid this, the difference between the attaching / detaching direction of the roller cleaning member 4 and the contact direction of the image bearing member of the charging roller is 90 degrees or more. In the example shown in FIG. 4, the direction of the arrow R is configured with a difference of 90 degrees or more with respect to the arrow Q, so that the roller-shaped cleaning member 4 is not rubbed when the charging roller 3 is attached or detached.

  Thus, while the charging roller 3 is attached to and detached from the image carrier, the roller-like cleaning member 4 is attached and detached at an angle of 90 ° or more with respect to the charging roller attaching and detaching direction. The cleaning member 4 can be separated from the charging roller 3 without rubbing, and the charging roller 3 after the replacement of the cleaning roller 4 can be used stably.

  The turning arm 11 can turn around a fulcrum shaft 14 as a fulcrum. The rotating arm 11 has a recess 11a for holding the cored bar (shaft part) 4a of the roller-shaped cleaning member 4 on the free end side of the fulcrum, and supports the cored bar 4a in the recessed part 11a to form the opening guide groove 5b. The metal core 4a is transported between the outside and the inside of the open guide groove 5b.

  In this conveyance process, the size of the recess 11a is made larger than that of the open guide groove 5b in order to prevent the cored bar 4a from being caught between the open guide groove 5b and the recess 11a. The direction of the open guide groove 5b is set to be a tangential direction of a circle with the fulcrum shaft 14 as the center.

  Here, as shown in FIG. 6, the attachment / detachment direction of the roller-shaped cleaning member 4 with respect to the charging roller 3 is the arrangement of the charging roller 3 with the common tangent line U of both rollers as a boundary in the state seen from the axial longitudinal direction of the charging roller 3 By setting the direction in the region opposite to the side where the roller is attached and the direction within a range of 180 degrees centering on the contact point W of both rollers, the influence of rubbing of both rollers during attachment and detachment is eliminated.

  In this example, the roller-shaped cleaning member 4 is configured to be able to contact and separate from the charging roller 3, so that the replacement timing of the charging roller 3 and the roller-shaped cleaning member 4 is easily different. It is possible to avoid the influence of one roller transferring dirt to the other roller.

  In addition, since the support member of the charging roller 3 and the support member of the roller-shaped cleaning member 4 are formed of the integral support member 5, the positional relationship between the charging roller 3 and the roller-shaped cleaning member 4 can be easily and accurately regulated. This makes it possible to further increase the margin for charging roller contamination when the cleaning roller is detached.

<Operational structure of rotating arm>
The operation configuration of the rotating arm 11 will be described. In FIG. 7, the turning arm 11 includes a locking portion 15 on the free end side. A slide piece 16 is slidably fitted to the main body member 2a of the charging device 2. The end portion of the slide piece 15 protruding from the main body member 2a toward the locking portion 15 can lock the locking portion 15.

  A stopper 16a larger in diameter than the hole for penetrating the slide piece 15 formed in the main body member 2a is integrated on the extension of the slide piece 15 that is inserted through the main body member 2a and located on the back side. 16a is urged by an extensible spring 17 so as to push the slide piece 15 toward the hook 15 side.

  The sliding of the slide piece 15 by this urging force is blocked by a stopper 16 a at a position where the slide piece 16 engages with the locking portion 15. The tip of the slide piece 15 is connected to the plunger 18 a of the solenoid 18. When the solenoid 18 is turned on, the tip of the slide piece 15 is retracted to a position where it does not engage with the locking portion 15.

  The position of the tip portion of the slide piece 15 is set to a position where the locking portion 15 can be locked at the rotation position of the rotation arm 11 in a state where the concave portion 11a is positioned below the cored bar 4a. The free end of the rotating arm 11 is pulled by a spring 19 and is urged clockwise in FIG.

  The rotation of the rotating arm 11 by this urging force is stopped when the locking portion 15 is applied to the slide piece 16. Further, when the engagement between the locking portion 15 and the slide piece 16 is released, the concave portion 11a is stopped by a stopper (not shown) at a position where the core metal 4a has escaped from the open guide groove 5b.

  In a state where the roller-shaped cleaning member 4 is in regular contact with the charging roller 3, as shown in FIG. 4, the cored bar 4a is slightly lifted from the bottom of the open guide groove 5b as shown in FIG. The bottom of the recess 5b is slightly below the bottom of the open guide groove 5b. As shown in FIG. 7, the slide piece 16 locks the locking portion 15, and the rotating arm 11 is rotated by the spring 19. Blocking. This is the state during normal image formation.

  When the roller-like cleaning member 4 is replaced, the solenoid 18 is temporarily turned on when the roller-like cleaning member 4 is removed from the support member 5. Then, since the plunger 18a is retracted, the locking by the slide piece 16 is released, the rotating arm 11 is rotated by the biasing force of the spring 19, and the roller-shaped cleaning member 4 is released from the state in contact with the charging roller. The rotation is stopped by a stopper (not shown) at a position where it is brought into the state and carried to the outside of the open guide groove 5b. Then grab it with your hand and carry it out. At this stage, the charging roller 3 is sufficiently separated from the charging roller 3 so that the charging roller 3 is not soiled.

  In this operation, the roller-shaped cleaning member 4 accurately moves along a predetermined locus in a predetermined direction that does not rub against the charging roller 3 at a speed at which the dirt does not drop, so that the dirt is not transferred to the charging roller. At the time of mounting, with the solenoid 18 turned off, the new roller-shaped cleaning member 4 after replacement is supported by the recess 11a, and the rotating arm 11 is manually pushed down. Due to this operation, the locking portion 15 eventually gets over the slide piece 16, so when the hand is released and the external force is removed, the locking state shown in FIG. 7 is obtained.

  As described above, when the roller-like cleaning member 4 that may contaminate the charging roller 3 is removed, the charging roller 3 is not soiled because the mechanical operation is performed accurately and stably.

  In addition, when attaching / detaching the roller-shaped cleaning member 4, parts around the exterior are also attached / detached. For example, the roller-like cleaning member 4 appears when the roller-like cleaning member cover 13 is removed from the position shown in FIGS. 8 and 10 in a direction substantially opposite to the photosensitive member 1 as shown in FIG. The member 4 is removed.

<Material of roller-shaped cleaning member>
As shown in FIG. 11, the roller-like cleaning member 4 has a surface portion 4b made of a porous material (foam). Porous materials include thermoplastic elastomer polystyrene elastomer, polyolefin elastomer, polyurethane elastomer, general-purpose resin polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, ABS, engineering plastics, polyacetal, polybutylene terephthalate. , Nylon and the like. Among them, a melamine foam resin having a high expansion ratio and a large surface area is excellent in deposit removal. As a result, it is possible to adopt a configuration in which a large amount of dirt substances are collected and not reattached, and the margin against the charging roller dirt when the cleaning roller is detached can be further increased.

  By using a melamine foam having a large surface area for the surface portion 4b, it becomes possible to make a structure that collects more deposits and does not re-adhere, and further increases the margin for charging roller contamination when the cleaning roller leaves. It becomes possible.

[3] Process Cartridge As shown in FIG. 12, the photosensitive member 1 and the charging device 2 are integrally supported by a photosensitive member support 21 and a process cartridge 22 is configured to be detachable from the main body of the image forming apparatus. . Further, a process cartridge to which the developing device 6 and the cleaning device 8 are added is also possible.

  In the case of a process cartridge, when an abnormality occurs in one of the components included in the process cartridge, it is necessary to replace the entire cartridge, and the components that are still in service life are discarded, which is not economical. However, by adopting the configuration described in each of the above examples, the charging roller 3 and the roller-shaped cleaning member 4 are appropriately cleaned, replaced, etc., so that problems due to contamination of the charging member can be prevented over a long period of time. The advantage (good workability) can be utilized.

1 is a schematic configuration diagram of an image forming apparatus including a charging device of the present invention. It is the figure which showed the structure around a charging roller and a roller-shaped cleaning member. It is the figure which showed the surroundings of a charging roller and a roller-shaped cleaning member. It is a figure explaining the attachment / detachment direction of a charging roller and a roller-shaped cleaning member. It is the figure which showed the positional relationship of a charging roller and the roller-shaped cleaning member supported by the rotation arm. It is a figure explaining the separation direction of the roller-shaped cleaning member with respect to the charging roller. It is a figure explaining the means of energizing and rotation prevention of a rotation arm. It is the figure explaining the apparatus structure around the exterior of a roller-shaped cleaning member. It is the figure which showed the removal state of the exterior periphery components at the time of roller-shaped cleaning member attachment / detachment. It is sectional drawing of a charging device. It is an external appearance perspective view of a roller-shaped cleaning member. It is an external appearance perspective view of a process cartridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Charging roller 4 Roller-shaped cleaning member 5 Support member 5b Opening guide groove 5a Groove 6 Developing device 11 Rotating arm 11a Recess 12 Charging frame 13 Roller-shaped cleaning member cover 14 Support shaft 21 Photoconductor support 22 Process cartridge

Claims (11)

A charging device for charging an endless movable image carrier,
The charging roller includes a charging roller, a supporting member that supports the charging roller, and a roller-shaped cleaning member that cleans the charging roller. The charging roller is slidably fitted to a shaft portion of the roller-shaped cleaning member, and the charging roller provided an open guide groove toward the shaft center, the roller-shaped cleaning member with respect to the charging roller, the charging apparatus detachably configured solely along the opening guide groove,
A charging device, characterized in that it comprises a pivoting arm Before moving the shaft portion of the roller-shaped cleaning member to the open guide groove to hold the shaft from the outside of the open guide grooves of the roller-shaped cleaning member . The charging device according to claim 1,
A charging device characterized in that the charging roller is detachably attached to the roller-shaped cleaning member. The charging device according to claim 1 or 2 ,
A charging device, characterized in that the depth of the guide grooves is set so that both rollers can be circumscribed in a state where the shaft portion is fitted before Symbol open guide groove to the roller-shaped cleaning member. The charging device according to any one of claims 1 to 3,
The attaching and detaching direction of the roller-shaped cleaning member with respect to the charging roller is within a region opposite to the side where the charging roller is disposed with a common tangent line between both rollers as seen from the longitudinal direction of the charging roller. In addition, the charging device is characterized in that the direction is within a range of 180 degrees centering on the contact point of both rollers. The charging device according to any one of claims 1 to 4,
A charging device comprising: a supporting member that supports the charging roller; and a supporting member that supports the roller-shaped cleaning member. The charging device according to any one of claims 1 to 4,
The charging device, wherein the roller-shaped cleaning member is capable of coming into contact with and separating from the charging roller. The charging device according to any one of claims 1 to 6,
The roller-like cleaning member has a surface made of a porous material (foam). The charging device according to any one of claims 1 to 7,
The roller-like cleaning member has a porous material (foam) on the surface, and the porous material is a melamine foam.   In a process cartridge that integrally supports an image carrier and at least one means selected from a charging device, a developing device, and a cleaning device, and is detachably attached to an image forming apparatus main body, the charging device comprises: 9. A process cartridge which is the charging device according to any one of 1 to 8. In an image forming apparatus having a charging device,
An image forming apparatus, wherein the charging device is the charging device according to claim 1. The image forming apparatus according to claim 10.
The charging roller and the roller-like cleaning member are configured to be detachable separately, and a difference between the attaching / detaching direction of the roller-like cleaning member and the contact direction of the image bearing member of the charging roller is 90 degrees or more. An image forming apparatus comprising the above.

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