JP2010217426A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device having such a configuration that the contamination to peripheries due to the scattering of toner can be prevented by reliably suppressing the generation of scattered toner caused by the clogging of a filter. <P>SOLUTION: In the developing device 12 in which an opening 120A for exposing part of a developer carrier 12A is formed in part of a developing container 120 capable of storing a two-component system developer, depressure openings 120B and 120C covered by the filter 121 are provided in the developing container 120 and a developer regulating member 200 having an opposite surface with which the developer moved toward the filter 121 collides directly is provided between the filter 121 and a space in the developing container 120, that is, a developer supply member, to prevent the movement of the developer. Alternatively, an air passage AP is provided so that air flows toward the filter, to prevent the clogging of the filter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus, and more particularly to a mechanism for preventing scattering of toner carried on a developer carrying member.

  As is well known, in an image forming apparatus such as a copying machine, a printer, or a printing machine, an electrostatic latent image formed on a photosensitive member, which is a latent image carrier, is visualized by a developer supplied from a developing device. It is processed. The image subjected to the visible image processing is transferred to a recording sheet or the like and fixed to be a copy output.

  In addition to a configuration using a one-component developer using only toner, a developing device used for visible image processing of an electrostatic latent image has a configuration using a two-component developer in which toner is attached to a carrier. It has been.

  A developing device using a two-component developer includes a magnetic brush by causing a two-component developer containing toner and a magnetic carrier to stand on the surface of a developing sleeve as a developing carrier having a plurality of magnetic poles. The structure to be formed is well known as a magnetic brush developing device.

  The developing sleeve carrying the magnetic brush on the surface makes contact with the electrostatic latent image formed by bringing the magnetic brush carried by rotation into contact with the electrostatic latent image formed on the surface of the photoreceptor, which is a latent image carrier. The toner in the developer is transferred to the electrostatic latent image by the electrostatic attractive force generated between the two.

  By the way, in the image forming apparatus, there is a case in which an electric component that is weak against heat or a developer that deteriorates due to heat is cooled. Specifically, a cooling fan is used to remove the cooling fan. The structure which distribute | circulated the cooling air of this to a required location is proposed (for example, patent document 1).

  Patent Document 1 discloses a configuration in which a heat sink is disposed in the vicinity of a developing sleeve in a developing device, and cooling air that flows while contacting the heat sink is supplied by a fan.

  When cooling air is forcibly supplied by a cooling fan or the like as described above, the internal pressure in the developing device tends to increase, which may cause toner to scatter and contaminate the peripheral portion. is there.

  Conventionally, a configuration in which a seal member as a shielding member is provided at the opening edge of the developing device that exposes the developing sleeve has been proposed, but an increase in internal pressure in the developing device is suppressed. Therefore, the scattering of the toner leaking from the seal member cannot be reliably prevented.

  Therefore, conventionally, a configuration has been proposed in which a pressure relief opening is provided in a part of the developing tank separately from the opening for exposing the developing sleeve so as to face the photosensitive member, and the opening is covered with a ventable filter. (For example, Patent Document 2).

  Japanese Patent Application Laid-Open No. 2004-228561 includes a ventable filter provided so as to cover the opening for pressure release, and in order to eliminate clogging of the filter that captures toner that is about to scatter from the inside of the developing device. The structure which provided the member which can be rotated and can be cleaned in the rotation process is disclosed.

  The toner to be scattered from the inside of the developing device is a lot of floating toner due to insufficient charge amount, and is easily scattered outside the developing device by an air flow such as cooling air.

  In addition, in recent years, in order to meet the demand for higher image quality, the finer particle size of the toner used has been promoted, so that the fine particle size is separated from the clogging of the filter due to the pressure difference inside and outside the developing device. In other words, a toner that easily leaks from the seal member easily enters the filter, which causes a new problem of clogging.

  In this respect, in the configuration in which the filter is cleaned as disclosed in Patent Document 2, if the fineness of the filter and the size of the component constituting the developer are not correlated well, the cleaning is performed. However, there is a concern that the toner and the carrier that have entered the filter deep portion cannot be completely cleaned. If the cleaning cannot be performed completely, the pressure release malfunction due to the clogging of the filter occurs and the toner is scattered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus having a configuration capable of preventing contamination of peripheral portions, which is a problem caused by toner scattering by reliably suppressing the generation of scattered toner caused by filter clogging. To provide an apparatus.

In order to achieve this object, the present invention has the following configuration.
(1) A developer container that contains a two-component developer containing toner and a magnetic carrier, and a part of the developer container that is exposed from the exposure opening formed in the developer container, is opposed to the latent image carrier, and has an internal magnetic pole. A developer carrier capable of conveying the developer toward a portion facing the latent image carrier by raising the developer, and a developer supply for stirring and conveying the developer carried on the developer carrier A developing device that at least includes a member, and that performs a visible image processing on the electrostatic latent image formed on the latent image carrier with toner in a developer,
The developer container communicates with the inside and outside of the developer container separately from the opening for exposure, and is provided with a pressure relief opening that is covered with a filter and reduces the internal pressure in the developer container above the developer supply member.
A developing measure characterized in that a structure is provided between the filter and the inside of the developing container to prevent movement of toner from the developing container toward the filter.
(2) As a structure for preventing the movement of the toner, an agent regulating member composed of a cantilever plate member whose base end is integrated with the inner wall surface of the developing container is used. The developing device according to claim 1.
(3) As a structure for preventing the movement of the toner, a closed space portion that partially includes an air passage that can communicate with the pressure relief opening between the filter and the developing container, and covers the pressure relief opening. The developing device according to claim 1, wherein: is used.
(4) The development according to any one of claims 1 to 3, wherein the toner blocking structure is provided in a space between the pressure release opening and the developer supply member. apparatus.
(5) The developing device according to (2), wherein the agent restricting member includes a part of an air passage that can communicate with the pressure relief opening between the filter and the inside of the developing container. .
(6) The closed space portion is provided on a surface where the air passage does not face the developer supply member, and a surface facing the developer supply member is configured as a surface facing the developer supply member. The developing device according to claim 3.
(7) The agent regulating member or the closed space portion has a surface facing the pressure release opening formed in an area larger than the area of the pressure release opening, and the surface is separated from the pressure release opening. The developing device according to claim 2, wherein the developing device is provided at a position.
(8) The agent regulating member or the closed space portion is provided so as to be inclined so that the surface facing the pressure release opening approaches the filter in the pressure release opening along the rotation direction of the developer supply member. The developing device according to claim 2, wherein
(9) A space for removing air from the developer supply member side is provided on a surface of the agent regulating member facing the pressure release opening. The developing device according to any one of the above.
(10) The developing device according to any one of (1) to (9), wherein a small particle size polymerized toner is used as toner collected by a filter covering the pressure release opening.
(11) The developing device according to any one of claims 1 to 10, wherein the developer accommodated in the developing container is a premix developer.
(12) A process cartridge using the developing device according to any one of claims 1 to 9.
(13) An image forming apparatus using the process cartridge according to (12).

  According to the present invention, since the structure for preventing the movement of the toner from the inside of the developing container is provided between the filter and the developing container, the developer cannot be directly applied to the filter. Filter clogging can be prevented.

  In particular, in the agent regulating member and the closed space portion used as a structure for preventing the movement of the toner, the developer to be scattered from the inside of the developing container toward the filter is directly against the facing surface facing the developer supplying member. While colliding with the filter, entry into the filter is prevented. On the other hand, since the space formed between the developer supply member and the filter is an air passage, air is allowed to pass through and the filter is ventilated.

  Thereby, the cause of clogging can be eliminated without using special measures such as cleaning the filter.

1 is a schematic diagram illustrating an example of an image forming apparatus in which a process cartridge equipped with a developing device according to the present invention is used. FIG. 2 is a partial front sectional view showing a schematic configuration of a process cartridge equipped with a developing device according to the present invention. FIG. 3 is a perspective view of the process cartridge shown in FIG. 2. It is a schematic diagram for explaining a first embodiment of the developing device according to the present invention. FIG. 5 is a schematic diagram for explaining a modification of the main part of the developing device according to the first embodiment shown in FIG. 4. It is a perspective view which shows the principal part modification shown in FIG. It is a schematic diagram for demonstrating 2nd Example of the developing device by this invention. FIG. 8 is a perspective view of the second embodiment shown in FIG. 7. It is a schematic diagram for demonstrating 3rd Example of the developing device by this invention. It is a perspective view which shows the principal part of 3rd Example shown in FIG. FIG. 10 is a schematic diagram for explaining a modification of the main part of the developing device according to the third embodiment shown in FIG. 9. It is a perspective view which shows the principal part modification shown in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows the configuration of an image forming apparatus using a process cartridge equipped with a developing device according to the present invention.

  An image forming apparatus 100 shown in FIG. 1 is a copying machine capable of copying an original image by an electrophotographic method. However, the present invention is not limited to this, and a printer, a printing machine, a facsimile machine, and these functions are combined. It is possible to target the device. The copying machine 1 shown in FIG. 1 reads an image from the surface of an original and records it on various recording media (hereinafter referred to as “sheets”) such as recording paper, transfer paper, paper, and OHP film. Although the target is a monochrome copying machine that forms a copy image, it is also possible to target a full-color copying machine that can form images of different colors in a plurality of image forming units.

  In FIG. 1, reference numeral 100 denotes a copying machine main body (image forming apparatus main body). The copying machine main body 100 has an image reading device 200 mounted thereon and is placed on a sheet bank 300.

  On the image reading apparatus 200, an automatic document feeder 400 that can be opened and closed up and down with the back side as a fulcrum is provided.

  The copying machine main body 100 includes a drum-shaped photoreceptor 10 as an image carrier inside.

  In order to perform an image forming process, the photosensitive member 10 is developed from the charging device 11 arranged on the left side in the drawing in the order along the rotation direction (counterclockwise) A of the photosensitive member 10 to the lower side. A transfer device 13 is disposed on the right side, a transfer device 13 is disposed on the right side, and a cleaning device 14 is disposed on the upper side.

  In the developing device 12, a premix developer obtained by mixing a small particle size polymerized toner produced by a polymerization method and a carrier is used as the toner, and the polymerized toner is charged with an electrostatic latent image on the photoreceptor 10 using a developing roller. The electrostatic latent image is visualized by adhering to.

  Further, the transfer device 13 is configured by winding a transfer belt 17 between upper and lower rollers 15, 16 and presses the transfer belt 17 against the peripheral surface of the photoconductor 10 at the transfer position B.

  In FIG. 1, what is provided on the left side of the charging device 11 and the cleaning device 14 is a toner replenishing device 20 that replenishes the developing device 12 with new toner.

Further, inside the copying machine main body 100, a sheet conveying apparatus C that conveys a sheet (recording medium) S fed from a sheet cassette 61 (described later) of the sheet bank 300 from the lower side to the upper side through the transfer position B to the stack position. Is prepared.
The sheet conveying apparatus C has a supply path R1, a manual feed path R2, and a sheet conveyance path R.
In the sheet conveyance path R, a pair of registration rollers 21 is provided at an upstream position of the photoconductor 10.

  Further, a fixing device 22 is provided at a downstream position of the photoconductor 10. As will be described in detail later, the fixing device 22 is provided with a heating roller (heating member) 30 that heats to a fixing temperature and a pressure roller (pressure member) 32 that presses against the heating roller.

  Further downstream of the fixing device 22, a discharge branch claw 34, a discharge roller 35, a first pressure roller 36, a second pressure roller 37, and a waist roller 38 are provided. Further, a discharge stack unit 39 for stacking sheets on which images have been formed is provided at the end.

The copying machine main body 100 is provided with a switchback device 42 on the right side in the drawing.
The switchback device 42 branches from the discharge branch claw 34 position of the sheet conveyance path R and leads to the switchback position 44 including the pair of switchback rollers 43, and the sheet conveyance path R again from the switchback position 44. A sheet conveying device D having a re-conveying path R4 leading to the registration roller 21.
The sheet conveying apparatus D is provided with a plurality of pairs of sheet conveying rollers 66 for conveying the sheet.

On the left side of the developing device 12 in the figure, a laser writing device 47 is provided.
The laser writing device 47 includes a laser light source (not shown), a scanning rotary polygon mirror 48, a polygon motor 49, a scanning optical system 50 such as an fθ lens, and the like.

On the other hand, the image reading apparatus 200 is provided with a light source 53, a plurality of mirrors 54, an imaging optical lens 55, an image sensor 56 such as a CCD, and the like, and a contact glass 57 is disposed on the upper surface.
The automatic document feeder 400 on the contact glass 57 is provided with a document setting table (not shown) at the document placement position and a document stack table (not shown) at the discharge position. Further, there is provided a sheet conveying apparatus having an unillustrated original conveying path for conveying the original sheet from the original setting table to the original stacking stage through the reading position on the contact glass 57 of the image reading apparatus 200.
The sheet conveying apparatus is provided with a plurality of sheet conveying rollers (not shown) that convey the document sheet.

  On the other hand, the sheet bank 300 is internally provided with a plurality of sheet cassettes 61 for storing sheets S as recording media. The sheet cassette 61 corresponds to a characteristic part of the present embodiment, and the configuration thereof will be described in detail later.

Each sheet cassette 61 is provided with a call roller 62, a supply roller 63, and a separation roller 64, respectively.
On the right side of the sheet cassette 61 provided in multiple stages in the drawing, the above-described supply path R1 leading to the sheet conveyance path R of the apparatus main body 100 is formed.
The supply path R1 is also provided with several sheet conveyance rollers 66 for conveying the sheet.

The copier apparatus main body 100 is provided with a manual feed unit 68 on the right side in the drawing. The manual feed unit 68 is provided with a manual feed tray 67 that can be opened and closed. 67 is provided with the above-described manual feed path R2 for guiding the manual sheet set on the sheet 67 to the sheet conveyance path R.
Similarly, the manual feed tray 67 is provided with a calling roller 62, a supply roller 63, and a separation roller 64.

  When making a copy using a copying machine having such a configuration, a main switch (not shown) is turned on and a document is set on a document setting table of the automatic document feeder 400.

  In the case of a book document, the automatic document feeder 400 is opened, a document is set directly on the contact glass 57 of the image reading device 200, and the automatic document feeder 400 is closed and pressed.

  When a start switch (not shown) is pressed, when the document is set on the automatic document conveying device 400, the document is moved by the sheet conveying roller through the document conveying path onto the contact glass 57 and the image reading device 200 is driven. Then, the document contents are read and discharged onto the document stacking table.

  On the other hand, when the document is set directly on the contact glass 57, the image reading apparatus 200 is immediately driven.

  When the image reading apparatus 200 is driven, the image reading apparatus 200 moves the light source 53 along the contact glass 57, reflects light from the light source 53 on the original surface on the contact glass 57, and reflects the reflected light to a plurality of light sources 53. The light is reflected by a mirror 54, passes through an imaging optical lens 55, is put in an image sensor 56, and the image content is read by the image sensor 56.

  In the illustrated example, the original is stopped on the contact glass 57 and moved toward the light source 53 to read the original content. On the contrary, the original surface is irradiated with light from a fixed light source while conveying the original. Of course, it is also possible to read the data sequentially.

  When the start switch is pressed, the photosensitive member 10 is rotated by a photosensitive member driving motor (not shown) at a predetermined timing, and in the illustrated example, the surface is first uniformly charged by a charging device 11 using a charging roller, and then the surface is charged. In accordance with the content of the original read by the image reading apparatus 200 described above, laser light is irradiated and writing is performed by the laser writing apparatus 47 to form an electrostatic latent image on the surface of the photosensitive member 10. A toner is attached to make the electrostatic latent image visible.

  Further, when the start switch is pressed, the sheet S is sent out by the calling roller 62 from the sheet cassette 61 corresponding to the selected size in the plurality of sheet cassettes 61 provided in multiple stages in the sheet bank 300 at a predetermined timing, and then the supply roller 63. The sheet is separated and conveyed one by one by the separation roller 64, and is fed into the supply path R1. The sheet is conveyed by the sheet conveyance roller 66 to the sheet conveyance path R, and is abutted against the registration roller 21 and stopped. Then, the registration roller 21 is rotated in synchronization with the rotation of the toner image visualized on the photosensitive member 10 described above, and is sent to the right side of the photosensitive member 10.

  Alternatively, the manual feed tray 67 of the manual feed unit 68 is opened, the manual sheet set on the manual feed tray 67 is sent out by the calling roller 62, and separated and conveyed one by one by the subsequent supply roller 63 and separation roller 64. The sheet is fed into the manual feed path R2, is conveyed by the sheet conveyance roller 66, is guided to the sheet conveyance path R, and is similarly fed to the right side of the photosensitive member 10 by the registration roller 21 in synchronization with the rotation of the photosensitive member 10.

  In the illustrated example, the transfer device 13 transfers the toner image on the photoconductor 10 to the sheet S fed to the right side of the photoconductor 10 to form an image. Residual toner on the photoconductor 10 after image transfer is removed and cleaned by a cleaning device 14, and the residual potential on the photoconductor 10 is removed by a neutralization device (not shown) to prepare for the next image formation starting from charging.

  The sheet S after image transfer is conveyed by the transfer belt 17 and put into the fixing device 22, passed between the heating roller 30 and the pressure roller 32, and conveyed by the rotating heating roller 30 and pressure roller 32. The toner image on the sheet S is fixed by applying heat and pressure. Thereafter, the sheet S is discharged onto the discharge stack portion 39 in a state in which the sheet S is bent and the bending rigidity is increased by the discharge roller 35, the first pressure roller 36, the second pressure roller 37, and the waist roller 38. Loaded.

  In addition, when transferring an image to both surfaces of the sheet, the discharge branch claw 34 is switched. Then, the sheet having the toner image transferred to the surface is transferred from the sheet conveying path R to the reversing path R3, conveyed by the sheet conveying roller 66 to the switchback position 44, and switched back by the switchback roller 43 to be re-conveyed. Inverted in the path R4, transported by the sheet transport roller 66, guided again to the sheet transport path R, and the image is transferred to the back surface of the sheet in the same manner as described above.

  In the copying machine 100, which is an image forming apparatus having the above-described configuration, as shown in FIGS. 2 and 3, a charging device 11, a developing device 12, and a cleaning device that perform an image forming process using the photoreceptor 10. The apparatus 14 is collectively accommodated in the process cartridge.

  FIG. 2 is a schematic diagram showing the configuration of the process cartridge 1000. In FIG. 2, the process cartridge 1000 is composed of a casing 1000A having a space in which each of the above-described devices can be accommodated. The process cartridge 1000 itself is detachably attached to the copying machine main body 100 so that maintenance and replacement work can be facilitated.

  The developing device 12 incorporated in the process cartridge 1000 described above is a characteristic part of the present invention, and a configuration relating to the characteristic will be described below.

  FIG. 4 is a view showing a first embodiment for explaining the mode according to the present invention. In FIG. 4, the developing device 12 has a space for accommodating a premix developer in which toner and carrier are mixed. And a developing container 120 constituting a developing tank.

  The developing container 120 includes a developing sleeve 12A used as a developer carrying member, a conveying screw 12B as a developer supplying member that stirs and conveys the developer in the developing container 120 in the direction of the arrow in the drawing, and a developing unit. A doctor blade 12C is provided as a layer thickness defining member for defining the layer thickness of the developer carried on the surface of the sleeve 12A.

  The developing sleeve 12 </ b> A has a magnetic pole for causing the developer to rise inside, and a part of the peripheral surface faces the opening 120 </ b> A formed in the developing container 120 so as to face the photoconductor 10. .

  In addition to the exposure opening 120A, the developing container 120 is formed with pressure release openings 120B and 120C for communicating the inside and outside of the development container 120 to reduce the internal pressure inside the container. 120C is covered by a filter 121.

  The filter 121 is used as a member for collecting the developer to be scattered from the inside of the container and allowing the air to pass through. The foam 121 has a mesh size smaller than the particle size of the toner to be collected. A porous material such as a nonwoven fabric is selected.

  In such a developing device 12, the developing container 120 is provided with a structure for preventing the movement of the toner moving from the developing container toward the filter.

  In the configuration shown in FIG. 4, the agent regulating member 200 disposed inside the filter 121 and the developing container 120, specifically, between the conveying screw 12 </ b> B, is used as a structure for preventing toner movement. Yes.

  The agent restricting member 200 is formed of a cantilever plate member that has a proximal end integrated with an inner wall surface at a position corresponding to the pressure release opening 120 </ b> C in the inner wall surface of the developing container 120 and projects in the horizontal direction. This is used as a barrier that prevents the developer from entering the filter 121.

  The agent regulating member 200 has a facing surface facing the conveying screw 12B in the developing container 120, and is located in a space portion away from the pressure relief opening 120C covered by the filter 121, and has the pressure relief opening 120C. It has a size to cover, and the tip is close to the rotation locus of the conveying screw 12B.

  When the conveying screw 12B rotates, the agent regulating member 200 having such a configuration directly applies the developer to be scattered toward the pressure release opening 120C, in other words, to the filter 121 by centrifugal force, on the surface facing the conveying screw 12B. It is made to collide and the penetration | invasion to the filter 121 is prevented.

  On the other hand, the agent regulating member 200 is provided at a position away from the pressure release opening 120 </ b> C, so that the separated portion is configured as an air passage (indicated by reference sign AP for convenience) through which air flows.

Since the present embodiment is configured as described above, it is wound up in the developing container 120 by taking advantage of the centrifugal force generated by the rotation of the conveying screw 12B or the rotation of the developing sleeve 12A or the airflow generated by the rotation or the cooling air. The developed developer collides with the agent regulating member 200 that forms a screen-like facing surface with respect to the conveying screw 12B and is prevented from proceeding to the filter 121 side.
At this time, the air flows around the air passage AP between the tip of the agent regulating member 200 and the pressure release opening 120C, passes through the pressure release openings 120B and 120C and the filter 121, and is discharged to the outside.
As a result, the internal pressure of the developing container 120 is quickly reduced, and toner scattering from the developing container 120 to the outside accompanying an increase in internal pressure is prevented.

  FIG. 5 is a view showing a modification of the main part of the configuration shown in FIG. 4. In FIG. 5, in addition to the air passage AP described above, an air passage is also provided on the agent regulating member 200 side.

  That is, on the base end side of the agent restricting member 200, as indicated by reference numeral AP1 in FIGS. 5 and 6, a part of the agent restricting member 200 formed of a plate member is similar to the pressure relief openings 120B and 120C, or An air passage is formed by an opening having a shape smaller than the opening area of the air passage AP.

  In this configuration, in addition to the amount of air in the developing container 120 that bypasses the tip of the agent regulating member 200, the air can pass through a different route from the tip side, so that the air can be easily released to the filter 121. Effective for reducing internal pressure. Moreover, since the air passage AP1 on the agent regulating member 200 side has a small area with respect to the air passage AP, even if the developer tries to enter directly, the amount thereof can be small.

  Next, a second embodiment of the present invention will be described. The same members as those shown in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted.

  FIGS. 7 and 8 are views corresponding to FIGS. 4 and 6 showing a second embodiment of the developing device according to the present invention. The configuration shown in FIG. 7 is an agent regulating member (indicated by reference numeral 200 ′ for convenience). The tip is inclined so as to approach the filter 121 along the direction of rotation of the conveying screw 12B (in the direction of the arrow in the figure), not at a right angle to the inner wall surface of the developing container 120. In other words, it is not parallel to the filter 121 but is inclined so that the tip approaches the filter 121.

  Since the present embodiment is configured as described above, the developer wound up from the conveying screw 12b collides with the agent regulating member 200 ′ functioning as a screen-like facing surface with respect to the conveying screw 12B, and thereby enters the filter 121 side. Intrusion is prevented.

  In this embodiment, since the agent regulating member 200 ′ is inclined, the developer can move along the inclined opposed surface unlike the case where the developer collides with the opposed surface and is prevented from moving. As a result, the impact force at the time of collision may be reduced, so that adverse effects such as peeling of the external additive of the toner due to the impact are less likely to occur.

  In this embodiment as well, although not shown, it is also possible to provide an air passage on the base end side of the agent regulating member 200 'as in the case shown in FIG.

Next, a third embodiment of the present invention will be described.
FIGS. 9 and 10 are views corresponding to FIG. 4 showing a third embodiment relating to the developing device. In FIG. 9, the developing device 12 is replaced with an agent regulating member 200 comprising a plate member shown in FIG. An air passage AP is formed in the part, and a closed space 300 having a surface facing the conveying screw 12B is provided.

  As in the case of the agent regulating member 200, the closed space 300 corresponds to a bottom surface that protrudes from the inner wall surface of the developing container 120 at a right angle in the horizontal direction, and is opposed to the conveying screw 12B. And a right angle (vertical) surface, and is integrated with the inner wall surface of the developing container 120, and an air passage AP is provided on the right angle surface.

  Since the present embodiment is configured as described above, the developer that is swirled and swung up by the rotation of the conveying screw 12B collides with the facing surface of the closed space portion 300, and is prevented from entering the filter 121.

  On the other hand, air such as airflow or cooling air generated by the rotation of the conveying screw 12B passes through the air passage AP formed in the closed space 300 toward the filter 121 and is exhausted, so that the internal pressure of the developing container 120 is reduced. It will be.

  In this embodiment, since the inside of the closed space 300 can also function as a decompression chamber, the scattered toner that has entered the filter 121 is caused by the decompression effect due to the expansion space obtained in the decompression chamber with respect to air and AP. Since the moving speed is reduced and it is easy to fall into the decompression chamber due to gravity, the intrusion into the filter 121 is more effectively suppressed.

  FIGS. 11 and 12 are views showing a modification of the main part of the embodiment shown in FIG. 9, and the configuration of the embodiment shown in the figure is a conveying screw 12B in a closed space portion (indicated by reference numeral 300 ′ for convenience). 9 is a configuration in which the facing surface facing the side is inclined instead of the horizontal direction shown in FIG.

  The inclination in this case is inclined in a direction approaching the filter 121 along the rotation direction of the conveying screw 12B, similarly to the configuration shown in FIG. In other words, it is not parallel to the filter 121 but is inclined so that the tip approaches the filter 121.

  In this configuration, the developer that directly contacts the opposing surface is prevented from entering the filter 121, and the external additive can be prevented from being peeled off due to the impact mitigating action due to the inclination.

  In the embodiment as described above, the developer that rises from the conveying screw 12B side does not directly enter the filter 121 by colliding with the opposing surface, so that the filter 121 is prevented from being clogged, and the developer container due to clogging is prevented. The increase in the internal pressure of 120 can be suppressed to prevent the toner from scattering to the outside of the developing device due to the increase in the internal pressure, and in particular, the filter can be clogged without the need for cleaning or the like with a simple configuration using only the opposite surface as a barrier. It can be prevented for a long time.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 12 Developing apparatus 12A Developing sleeve 12B Conveying screw 12C Doctor blade 120 Developing container 120A Exposing opening 120B, 120C Depressurizing opening 200, 200 'Agent regulating member 300 Closed space portion AP, AP1 Air passage 1000 Process cartridge

JP 2007-24984 A JP 2004-20772 A

Claims (13)

A developer container containing a two-component developer containing toner and a magnetic carrier, a part exposed from the opening for exposure formed in the developer container, facing the latent image carrier, and the developer by a magnetic pole included in the developer container A developer carrying member capable of conveying the developer toward a portion opposed to the latent image carrying member, and a developer supply member for stirring and conveying the developer carried on the developer carrying member; In a developing device comprising at least an electrostatic latent image formed on the latent image bearing member and processing a visible image with toner in a developer,
The developer container communicates with the inside and outside of the developer container separately from the opening for exposure, and is provided with a pressure relief opening that is covered with a filter and reduces the internal pressure in the developer container above the developer supply member.
A developing measure characterized in that a structure is provided between the filter and the inside of the developing container to prevent movement of toner from the developing container toward the filter.   As a structure for preventing the movement of the toner, as a structure for preventing the movement of the toner, an agent regulating member constituted by a cantilever plate member whose base end is integrated with an inner wall surface of the developing container is provided. The developing device according to claim 1, wherein the developing device is used.   As a structure for preventing the movement of the toner, a closed space portion that partially includes an air passage that can communicate with the pressure relief opening between the filter and the developing container and covers the pressure relief opening is used. The developing device according to claim 1.   4. The developing device according to claim 1, wherein the toner blocking structure is provided in a space between the pressure release opening and the developer supply member. 5.   3. The developing device according to claim 2, wherein the agent regulating member includes a part of an air passage that can communicate with the pressure release opening between the filter and the inside of the developing container.   The closed space portion is provided on a surface where the air passage does not face the developer supplying member, and a surface facing the developer supplying member is configured as a surface facing the developer supplying member. The developing device according to claim 3.   The agent regulating member or the closed space portion has a surface facing the pressure release opening formed in an area larger than the area of the pressure release opening, and the surface facing the pressure release opening is provided at a position away from the pressure release opening. The developing device according to claim 2, wherein the developing device is provided.   The agent regulating member or the closed space portion is provided such that a surface facing the pressure release opening is inclined so as to approach the filter in the pressure release opening along the rotation direction of the developer supply member. The developing device according to claim 2, wherein the developing device is characterized in that:   8. A space for removing air from the developer supply member side is provided on a surface of the agent regulating member facing the pressure release opening. The developing device according to 1.   The developing device according to claim 1, wherein a small particle size polymerized toner is used as toner collected by a filter covering the pressure release opening.   The developing device according to claim 1, wherein the developer accommodated in the developing container is a premix developer.   A process cartridge using the developing device according to claim 1.   An image forming apparatus using the process cartridge according to claim 12.

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