JP2007164022A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device which surely prevents leakage of developer, while having a simple structure dispensing with high assembling accuracy. <P>SOLUTION: The developing device includes: a developing container 30 for storing the developer; a developer carrier 40 that carries the developer in the developing container 30; a seal member 50 provided so as to be wound on a part of or all of the outer peripheral surface of the developer carrier 40 at both longitudinal ends of the developer carrier 40; and a developer control plate 44 formed like a belt along the longitudinal direction of the developer carrier 40, and also, fixed to the developing container 30 at one end part thereof in the width direction, and also, the other end part in the width direction of which comes in contact with the outer peripheral surface of the developer carrier 40. Both longitudinal end parts of the developer control plate 44 are a pair of seal parts P, and an area sandwiched between the seal areas P is a non-seal area Q. A bent part 46 constituted by bending the leading end in the width direction toward a side separating from the developer carrier 40 is provided to the developer control plate 44, and the bent part 46 is provided only to the non-seal area Q on the developer regulating plate 44. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing device for supplying a developer to an electrostatic latent image carrier in an electrophotographic image forming apparatus, and a process cartridge and an image forming apparatus provided with the developing device.

  In general, an image forming apparatus such as a copying machine or a printer includes a developing device for developing a developer on an electrostatic latent image carried on an electrostatic latent image carrier such as a photosensitive member, The developing device includes a developing container having an elongated opening for discharging the developer, and a developing roller for supplying the developer carried in the developing container to the electrostatic latent image carrier through the opening. The developer carried on the developing roller reaches the developing area facing the electrostatic latent image carrier by the rotation of the developing roller, moves to the outer peripheral surface of the electrostatic latent image carrier in the developing area, and electrostatic latent The image is developed.

  By the way, in recent years, with the improvement of the resolution and sharpness of an image, the diameter of the developer has been reduced and the spheroid has been progressed. Therefore, the probability of occurrence of leakage is increasing even with a seal configuration in which no developer leakage has occurred in the past, and there is a need for improved sealing performance in the developing device. In addition, automation of parts assembly is progressing, and for that reason, relaxing the requirement of assembly accuracy is also a cause of developer leakage.

  As a conventional developing device, as shown in FIG. 8, a developing device having a developer regulating plate 74 that regulates the layer thickness of the developer carried on the developing roller 70 is known. The developer regulating plate 74 is formed in a belt shape along the longitudinal direction of the developing roller 70, the base end portion in the width direction is fixed to a developing container (not shown), and the tip end portion in the width direction contacts the outer peripheral surface of the developing roller 70. It is provided in contact. Further, the developer regulating plate 74 includes a bent portion 76 formed by bending the front end in the width direction to the side away from the developing roller 70. The developer carried on the developing roller 70 is regulated to a predetermined layer thickness when passing through the contact portion between the width direction front end portion of the developer regulating plate 74 and the developing roller 70, and the developer regulating plate 74 and the developing roller 70 are charged by friction.

  Further, the conventional developing device shown in FIG. 8 includes a seal member 80 for preventing the developer from leaking from both ends in the longitudinal direction of the opening of the developing container. The seal member 80 is provided in a state of being wound around a part of the outer peripheral surface at the end portion in the longitudinal direction of the developing roller 70. As shown in FIG. 9, the seal member 80 is a long member along the longitudinal direction of the developing roller 70, and is provided with seal portions 82 at both ends in the longitudinal direction.

  As shown in FIG. 9, both end portions in the longitudinal direction of the developer regulating plate 74 are seal regions P in which the seal portions 82 of the seal member 80 are overlapped. In this seal region P, as shown in FIG. 10, the bent portion 76 of the developer regulating plate 74 bites in, so that the seal portion 82 of the seal member 80 is deformed, and between the seal portion 82 and the outer peripheral surface of the developing roller 70. Since a gap 78 as shown in FIG. 8 is generated, the developer may leak from the gap 78.

In order to solve such a problem of sealing properties, in the developing device described in Patent Document 1, a cut portion for inserting a bent portion of the developer regulating plate is formed in the seal member. As a result, in the seal region at the front end in the width direction of the developer regulating plate, the bent portion of the developer regulating plate is inserted into the cut portion of the seal member, so that the seal member is prevented from being deformed, It is the structure which can prevent that a clearance gap produces between sealing members.
JP 2002-251068 A

However, the developing device described in Patent Document 1 has a drawback that it is necessary to accurately align the notch portion of the seal member and the bent portion of the developer regulating plate, and high assembly accuracy is required. Was. In other words, the developing device of Patent Document 1 has a problem that it is difficult to cope with automation of assembly, and the variation in assembly becomes large, so that the occurrence rate of developer leakage increases.
SUMMARY OF THE INVENTION Accordingly, the present invention provides a developing device capable of reliably preventing developer leakage while having a simple structure that does not require high assembly accuracy, and a process cartridge and an image forming apparatus including the developing device. With the goal.

In order to solve the above problems, a developing device, a process cartridge, and an image forming apparatus according to the present invention include:
A developer container containing a developer;
A developer carrying member carrying the developer in the developer container;
At both ends in the longitudinal direction of the developer carrier, a seal member provided to wrap around a part or the entire circumference of the developer carrier outer peripheral surface;
It is formed in a belt shape along the longitudinal direction of the developer carrier, and is fixed to the developer container at one end in the width direction, and the other end in the width direction is in contact with the outer peripheral surface of the developer carrier. A developer regulating plate in contact therewith,
At the other end in the width direction of the developer regulating plate, a region where the seal member is overlapped on the surface opposite to the contact surface with the developer carrier is defined as a seal region, and a region other than the seal region is defined. When the non-sealed area
In the developing device in which both end portions in the longitudinal direction of the developer regulating plate are a pair of seal regions, and a region sandwiched between the seal regions is a non-seal region,
The developer regulating plate includes a bent portion formed by bending the tip of the other end in the width direction to the side away from the developer carrier;
The bent portion is provided only in a non-seal region in the developer regulating plate.

  In addition, the bent portion is tapered so that the length in the longitudinal direction becomes shorter toward the tip on the other end side in the width direction.

  According to the present invention, since the bent portion provided at the front end in the width direction of the developer regulating plate is provided only in the non-seal area that does not overlap the seal member, the deformation of the seal member due to the biting of the bent portion is prevented. Can do. Thereby, it is possible to prevent a gap from being generated between the outer peripheral surface of the developer carrier and the seal member, and it is possible to reliably prevent the developer from leaking.

  In addition, since the present invention does not require a cut portion as in the above-described prior art, the position of the cut portion of the seal member and the bent portion of the developer regulating plate can be accurately aligned. There is an advantage that no dimensional control is required. Therefore, high assembly accuracy is not required, and automation of assembly can be easily handled.

  First, the 1st Embodiment of this invention is described based on FIGS. As shown in FIG. 1, the image forming apparatus 1 is an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multi-function machine having a combination of these functions. The image forming apparatus 1 may be either used alone or compatible with a network, and may be either monochrome output or color output.

  The schematic configuration of the image forming apparatus 1 is the same as that of a general electrophotographic image forming apparatus. That is, the image forming apparatus 1 includes a photoreceptor 2 as an electrostatic latent image carrier, and a charging device 4, an exposure device 6, a developing device 8, and a transfer device 10 are provided around the photoreceptor 2. A paper feeding device 12 and a fixing device 14 are provided in the paper conveyance path.

  Next, an example of an image forming operation by the image forming apparatus 1 will be briefly described. The photoconductor 2 that rotates counterclockwise in the figure is charged to a desired potential in a charging region facing the charging device 4. Subsequently, in the exposure region, exposure is performed by, for example, laser light emitted from the exposure device 6, and an electrostatic latent image based on the image data is formed on the surface of the photoreceptor 2. When the electrostatic latent image on the photosensitive member 2 reaches the developing region facing the developing device 8, a voltage is applied between the voltage applied to the developing roller 40 of the developing device 8 and the electrostatic latent image on the photosensitive member 2. Due to the applied electric field, the charged toner moves from the developing roller 40 to the photoreceptor 2, and the electrostatic latent image is developed with the toner.

  When the toner image on the photoreceptor 2 formed in this manner reaches the transfer area facing the transfer device 10, the toner image is transferred onto a sheet conveyed between the photoreceptor 2 and the transfer device 10 by the timing roller 16. Is done. The sheet on which the toner image is adhered by this transfer is further conveyed, and heat and pressure are applied by the fixing device 14 to fix the toner image on the sheet. Then, the sheet on which the toner image is fixed is discharged to the discharge tray 20 by the discharge roller 18. Note that toner remaining on the photoreceptor 2 without being transferred to the paper is collected by a cleaning device (not shown).

  However, the schematic configuration of the image forming apparatus 1 is not limited to the configuration described above. For example, in FIG. 1, the photosensitive member 2, the charging device 4, the transfer device 10, and the fixing device 14 are illustrated as having a roller shape, but are not necessarily limited to a roller shape, for example, a belt shape. A charging device such as a photosensitive member, a blade, a belt-shaped transfer device, and a belt-shaped fixing device may be used. Further, the exposure apparatus 6 is not limited to the laser system, and an LED system may be used. Further, the image forming apparatus 1 may be of a cleanerless type that does not have a cleaning device.

  The developing device 8 is formed into a cartridge so as to be detachable from the main body of the image forming apparatus 1. That is, the developing device 8 is integrally combined with the photoreceptor 2 to constitute a process cartridge. The process cartridge may be configured by combining other devices in addition to the developing device 8 and the photosensitive member 2.

  As shown in FIG. 2, the developing device 8 includes a developing container 30 for containing a developer. The developing container 30 includes a developing unit 32 for performing development by attaching a developer to the photosensitive member 2, and a replenishing unit 34 for replenishing the developing unit 32 with the developing unit 32 and the replenishing unit. 34 communicates with each other through a communication port 36. Further, the developing container 30 includes an elongated opening 38 for discharging the developer at the developing unit 32.

  The developing section 32 of the developing container 30 is provided with a developing roller 40 as a developer carrying member for carrying the developer in the developing container 30 and a supply roller 42 for supplying the developer to the developing roller 40. The developing roller 40 and the supply roller 42 are provided in contact with each other, and are rotatable about a rotating shaft (not shown) parallel to the longitudinal direction of the opening 38 of the developing container 30. The rotation shaft of the developing roller 40 and the rotation shaft of the supply roller 42 are connected to the same drive mechanism (not shown) so that the development roller 40 and the supply roller 42 are rotated by operating the drive mechanism. It has become.

  The developing roller 40 is provided so as to close the opening 38 over substantially the entire length in the longitudinal direction of the opening 38, and substantially half of the outer peripheral surface of the developing roller 40 is accommodated in the developing container 30. The remaining half is exposed to the outside of the developing container 30.

  The developing roller 40 rotates counterclockwise in FIG. 2, and the developer is supplied from the supply roller 42 in the developer supply region in contact with the supply roller 42. The developer supplied at this time is precharged by friction between the developing roller 40 and the supply roller 42. The developer supplied in this manner adheres to the outer peripheral surface of the developing roller 40 and is carried by the developing roller 40, and reaches the charged region in contact with the leading end portion of the developer regulating plate 44 described later by the rotation of the developing roller 40. In the charging region, the developer layer thickness is regulated by scraping off excess developer by the tip of the developer regulating plate 44, and a predetermined charge is given by frictional charging. The developer thus given a predetermined charge is discharged to the outside of the developing container 30 through the opening 38 by the rotation of the developing roller 40, and reaches a developing region facing the photoreceptor 2. The developer that has reached the development area moves from the developing roller 40 to the photoconductor 2 in accordance with the electrostatic latent image carried by the photoconductor 2, and a toner image is formed on the photoconductor 2.

  Further, the developing device 8 has a seal member 50 for preventing the developer from leaking from both ends in the longitudinal direction of the opening 40 of the developing container 30 and the layer thickness of the developer carried on the developing roller 40 as described above. And a developer regulating plate 44 for regulating the thickness to a predetermined thickness.

  The seal member 50 is provided to wrap around a part of the outer peripheral surface of the developing roller 40 at both ends in the longitudinal direction of the developing roller 40. However, it does not prevent the seal member 50 from being provided so as to be wound around the entire outer peripheral surface of the developing roller 40.

  The seal member 50 is, for example, a long member provided along the longitudinal direction of the developing roller 40, and as shown in FIG. 4, a pair of seal portions that wrap around the outer peripheral surfaces at both ends in the longitudinal direction of the developing roller 40. 52 and a pair of connecting portions 54 and 56 that connect between the ends of the pair of seal portions 52. Further, the seal member 50 includes an elongated opening 58 surrounded by a pair of seal portions 52 and a pair of connecting portions 54 and 56. As the seal member 50, for example, an elastic member made of a soft resin is used.

  However, the seal member 50 may have a shape other than the above as long as it includes a pair of seal portions 52. Further, it is not always necessary to use one seal member 50 provided with a pair of seal portions 52, and two seal members provided with one seal portion 52 may be used.

  The developer regulating plate 44 is formed in a strip shape along the longitudinal direction of the developing roller 40. As shown in FIG. 2, the developer regulating plate 44 is fixed to the developing container 30 at the base end portion in the width direction, and the front end portion in the width direction is a free end. The developer regulating plate 44 is provided such that the front end in the width direction is in contact with the outer peripheral surface of the developing roller 40.

  The front end in the width direction at both longitudinal ends of the developer regulating plate 44 is sandwiched between the outer peripheral surface of the developing roller 40 and the seal member 50. That is, a region where the seal member 50 is overlapped on the surface opposite to the contact surface with the developing roller 40 at the front end in the width direction of the developer regulating plate 44 is defined as a seal region P, and a region other than the seal region P is defined. As shown in FIG. 4, when the non-sealed area Q is formed, both ends in the longitudinal direction of the developer regulating plate 44 form a pair of sealed areas P, and the area sandwiched between the sealed areas P is the non-sealed area Q. It has become.

  Further, the developer regulating plate 44 includes a bent portion 46 formed by bending the front end in the width direction toward the side away from the developing roller 40. As shown in FIG. 4, the bent portion 46 is provided only in the non-seal region Q in the developer regulating plate 44. That is, as shown in FIG. 3, both side corners at the front end in the width direction of the developer regulating plate 44 have a stepped notch shape.

  As described above, since the bent portion 46 is provided only in the non-seal region Q, the bent portion 46 can be accommodated in the opening 58 of the seal member 50. Therefore, interference between the bent portion 46 and the seal member 50 can be avoided, and the bent portion 46 can be prevented from biting into the seal member 50. Therefore, in the seal region P, as shown in FIG. 5, deformation of the seal member 50 due to the biting of the bent portion 46 can be prevented, and a gap is prevented from being generated between the outer peripheral surface of the developing roller 40 and the seal member 50. can do.

  6 and 7 show a second embodiment of the present invention. Also in the second embodiment, as shown in FIG. 7, since the bent portion 66 is provided only in the non-sealed region Q, the bent portion 66 is prevented from biting into the seal member 50, and the outer peripheral surface of the developing roller 40. And the seal member 50 can be prevented from generating a gap.

  Moreover, the bending part 66 in 2nd Embodiment is made into the taper shape that the length of the longitudinal direction becomes short as it goes to the width direction front-end | tip. Therefore, even if the bent portion 66 comes into contact with the seal member 50, the deformation of the seal member 50 can be suppressed to an extremely low level, and the generation of a gap between the outer peripheral surface of the developing roller 40 and the seal member 50 can be further reduced. It can be surely prevented, and the sealing performance is further enhanced.

  In the second embodiment, other configurations and effects are the same as those of the first embodiment. In FIGS. 6 and 7, members having the same functions as those of the first embodiment are denoted by the same reference numerals. It is.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus. It is sectional drawing which shows a developing device. It is a principal part expansion perspective view which shows a developer control board and a sealing member. FIG. 4 is a diagram of a developer regulating plate and a seal member viewed from the developing roller side. It is sectional drawing which shows the developer control board and seal member in a seal | sticker area | region. It is a principal part expansion perspective view which shows the developer control board and seal member in 2nd Embodiment. It is the figure which looked at the developer control board and seal member shown in FIG. 6 from the developing roller side. It is sectional drawing which shows the conventional developer control board and a sealing member. It is the figure which looked at the conventional developer control board and the sealing member from the developing roller side. It is a principal part expansion perspective view which shows the conventional developer control board and a sealing member.

Explanation of symbols

1 image forming apparatus,
8 Development device,
30 developer container,
40 Development roller (developer carrier),
44 Developer restriction plate,
46, 66 Bending portion of developer regulating plate,
50 sealing member,
P seal area,
Q Unsealed area.

Claims (4)

A developer container containing a developer;
A developer carrying member carrying the developer in the developer container;
At both ends in the longitudinal direction of the developer carrier, a seal member provided to wrap around a part or the entire circumference of the developer carrier outer peripheral surface;
It is formed in a strip shape along the longitudinal direction of the developer carrier, and is fixed to the developer container at the base end in the width direction, and the front end in the width direction contacts the outer peripheral surface of the developer carrier. A developer regulating plate in contact therewith,
A region where the seal member is overlapped on the side opposite to the contact surface with the developer carrier at the front end in the width direction of the developer regulating plate is defined as a seal region, and a region other than the seal region is not sealed. When the area
In the developing device in which both end portions in the longitudinal direction of the developer regulating plate are a pair of seal regions, and a region sandwiched between the seal regions is a non-seal region,
The developer regulating plate includes a bent portion formed by bending the front end in the width direction to the side away from the developer carrier,
The developing device according to claim 1, wherein the bent portion is provided only in a non-sealed region of the developer regulating plate.   The developing device according to claim 1, wherein the bent portion has a taper shape whose length in the longitudinal direction becomes shorter toward the front end in the width direction.   A process cartridge comprising the developing device according to claim 1. An image forming apparatus comprising the developing device according to claim 1.

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