JP2010128181A - Developing device, process cartridge, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of preventing a toner from being fusion-fixed so as to be aggregated in the inside by pressure and a temperature by reducing the pressure, and an image forming device mounted therewith. <P>SOLUTION: The developing device has a conveying screw for conveying powder stored in a developing housing along an axial direction from an upstream to a downstream, and an elastic member 68 is provided on an inner circumferential face of the developing housing 76Y in the downstream of the conveying screw 55Yb. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, and a facsimile, a process cartridge including the developing device, and an image forming apparatus equipped with the process cartridge.

2. Description of the Related Art Conventionally, as shown in Patent Document 1, a two-component developing device including a carrier that is a magnetic material and toner has a toner transport screw for stirring and transporting the replenished toner and the carrier. In general, the conveying screw has a spiral shape for conveying in one direction (see, for example, Patent Document 1).
The developing device includes a toner conveying screw in the developing roller chamber and a toner conveying screw in the stirring chamber. The toner is replenished from the upstream of the stirring chamber according to the toner consumption. The replenished toner is mixed with the carrier and the toner in the agitating chamber, and is conveyed downstream of the agitating chamber along the spiral portion of the conveying screw.
Such a developing device has two screws which are a screw in the developing roller chamber and a screw in the stirring chamber (mixed with toner), and replenishes toner from the upstream of the stirring chamber according to toner consumption. The carrier and the toner are mixed in the stirring chamber and conveyed to the downstream of the stirring chamber along the spiral shape of the screw.
JP 2006-220852 A

However, the outer wall of the developing case is provided with a driving mechanism for rotating a screw, a developing roller, etc., and heat is generated due to the influence of the pressure angle of the gear meshing and the friction of the sliding portion such as the bearing.
Further, the toner is conveyed downstream by a spiral shape and is sent from the developing chamber to the stirring chamber or from the stirring chamber to the developing chamber by a rib or the like in the direction perpendicular to the axis. There is also a thing that stays due to a change in flow, so that there is a pressure in the most downstream direction.
When the temperature due to driving or the like exceeds the softening point of the toner and a powder pressure is applied, the toner aggregates on the downstream side of the screw or the wall surface of the case (melt fixation). These agglomerated toners are hardened when the rotation of the drive is stopped, chipped by re-driving, and there is a problem that when the toner rolls around the developing roller portion, the toner does not uniformly get on the developing roller.
In recent years, it is common to place the main body of the image forming apparatus in a standby state in order to save energy, but it is also required to increase the return time from the standby state. Returning from the standby state takes the longest time to return the temperature of the mechanism that fixes the transferred toner to the paper with heat and pressure to a predetermined value.
For this reason, many devices use a low melting point toner and lower the fixing temperature. However, when a low-melting toner is used, there is a problem that melting and fixing easily occur in the developing device.
Accordingly, an object of the present invention is to provide a developing device that prevents the toner from being melted and fixed and agglomerated inside due to pressure and temperature in consideration of the above situation, and an image forming apparatus equipped with the developing device. It is to provide.

In order to solve the above-mentioned problem, the invention according to claim 1 is a developing device having a conveying screw for conveying the powder accommodated in the developing housing along the axial direction from upstream to downstream. The developing device is characterized in that an elastic member is provided on a bearing-side inner wall surface of the developing housing downstream of the conveying screw.
The invention according to claim 2 is characterized in that the elastic member has a hardness of 50 ° (Asker-F) or less.
The invention according to claim 3 is characterized in that the elastic member is made of foamed polyurethane, and the foaming diameter of the foamed polyurethane is covered by a coating process.
According to a fourth aspect of the invention, there is provided the developing device according to any one of the first to third aspects, wherein the elastic member is provided downstream of the conveying screw on a side close to a high heat source such as a driving mechanism. To do.
According to a fifth aspect of the present invention, the developing device according to any one of the first to fourth aspects, wherein an outer shape of the elastic member is larger than an outer diameter of the conveying screw.
The invention according to claim 6 is characterized in that the developing device according to any one of claims 1 to 5, wherein an inner diameter of a shaft insertion hole provided in the elastic member is made smaller than an outer diameter of the shaft of the conveying screw. To do.
The invention according to claim 7 is characterized in that the developing device according to any one of claims 1 to 6, wherein the outer diameter of the elastic member is larger than the inner diameter of the hole in the end wall of the developing housing.
The invention according to claim 8 is characterized by a process cartridge including at least the developing device according to any one of claims 1 to 7 and an image carrier.
According to a ninth aspect of the present invention, there is provided an image forming apparatus that develops and visualizes an electrostatic latent image formed on an image carrier with toner from a developing device, and includes the developing device and the image carrier. An image forming apparatus comprising the process cartridge according to claim 8 as a process cartridge including the image forming apparatus.

  According to the present invention, by providing the elastic member downstream of the screw, the powder pressure generated by the screw is received by the elastic member and relaxed, and aggregation can be prevented. As a result, it is possible to prevent the powder from aggregating in the developing device and to prevent the toner from adhering unevenly on the developing roller, which is caused by the sandwiching of the aggregate.

Hereinafter, an electrophotographic printer (hereinafter simply referred to as a printer) will be described as an example of an embodiment of an image forming apparatus to which the present invention is applied. The image forming unit will be described as a process cartridge.
FIG. 1 is a schematic diagram showing the configuration of an electrophotographic printer. FIG. 2 is a schematic view showing a process cartridge for generating a Y toner image. First, the basic configuration of the printer will be described.
1 and 2, the printer 100 includes four process cartridges 6Y, 6M, 6C, for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). It has 6K. These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached.

First, a process cartridge 6Y for generating a Y toner image will be described as an example. As shown in FIG. 2, the process cartridge 6Y includes a drum-shaped photoconductor 1Y, a drum cleaning device 2Y, a charge eliminating device (not shown), a charging device 4Y, a developing device 5Y, and the like. The process cartridge 6Y can be attached to and detached from the main body of the printer 100 so that consumable parts can be replaced at a time.
The charging device 4Y uniformly charges the surface of the photoreceptor 1Y that is rotated clockwise in the drawing by a driving unit (not shown). The uniformly charged surface of the photoreceptor 1 </ b> Y is exposed and scanned by the laser beam L to carry an electrostatic latent image for Y. The Y electrostatic latent image is developed into a Y toner image by the developing device 5Y using Y toner.
This Y toner image is intermediately transferred onto the intermediate transfer belt 8. The drum cleaning device 2Y removes the toner remaining on the surface of the photoreceptor 1Y after the intermediate transfer process. Further, the static eliminator neutralizes residual charges on the photoreceptor 1Y after cleaning. By this charge removal, the surface of the photoreceptor 1Y is initialized and prepared for the next image formation.
In the other process cartridges 6M, 6C, and 6K, M, C, and K toner images are similarly formed on the photoreceptors 1M, 1C, and 1K, and are intermediately transferred onto the intermediate transfer belt 8.

In FIG. 1, the exposure device 7 is disposed below the process cartridges 6Y, 6M, 6C, and 6K. The exposure device 7 serving as a latent image forming unit irradiates the respective photosensitive members in the process cartridges 6Y, 6M, 6C, and 6K with a laser beam L emitted based on the image information to perform exposure.
By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The exposure device 7 irradiates the photoconductor with a laser beam (L) emitted from a light source through a plurality of optical lenses and mirrors while scanning with a polygon mirror rotated by a motor.
On the lower side of the exposure apparatus 7 in the figure, a sheet feeding means having a transfer sheet accommodating cassette 26, a sheet feeding roller 27 incorporated therein, a pair of registration rollers 28, and the like are disposed.
The transfer paper storage cassette 26 stores a plurality of transfer papers P, which are recording media, and a paper feed roller 27 is in contact with the uppermost transfer paper P.

When the paper feeding roller 27 is rotated counterclockwise in the drawing by a driving means (not shown), the uppermost transfer paper P is fed toward the rollers of the registration roller pair 28. The registration roller pair 28 rotationally drives both rollers to sandwich the transfer paper P, but temporarily stops rotating immediately after the sandwiching. Then, the transfer paper P is sent out toward a later-described secondary transfer nip at an appropriate timing.
In the sheet feeding unit having such a configuration, a conveying unit is configured by a combination of the sheet feeding roller 27 and the registration roller pair 28 which is a timing roller pair. This conveying means conveys the transfer paper P from a transfer paper storage cassette 26 which is a storage means of the transfer paper P to a secondary transfer nip described later.
Above the process cartridges 6Y, 6M, 6C, and 6K in the figure, an intermediate transfer unit 15 that moves the intermediate transfer belt 8 that is an intermediate transfer member endlessly while stretching is disposed. In addition to the intermediate transfer belt 8, the intermediate transfer unit 15 includes four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a cleaning device 10, and the like.

A secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14 and the like are also provided. The intermediate transfer belt 8 is endlessly moved in the counterclockwise direction in the figure by the rotational drive of at least one of the rollers while being stretched around these three rollers.
The primary transfer bias rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 that is moved endlessly in this manner from the photoreceptors 1Y, 1M, 1C, and 1K to form primary transfer nips, respectively. Yes.
These primary transfer bias rollers 9Y, 9M, 9C, and 9K are of a system that applies a transfer bias having a polarity opposite to that of toner (for example, plus) to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All the rollers except the primary transfer bias rollers 9Y, 9M, 9C, and 9K are electrically grounded.
The intermediate transfer belt 8 passes through the primary transfer nips for Y, M, C, and K sequentially along with the endless movement thereof, and the Y, M, and Y on the photoreceptors 1Y, 1M, 1C, and 1K are sequentially transferred. The C and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 8.

The secondary transfer backup roller 12 described above forms a secondary transfer nip with the intermediate transfer belt 8 sandwiched between the secondary transfer backup roller 19 and the secondary transfer roller 19. The four-color toner image formed on the intermediate transfer belt 8 is transferred to the transfer paper P at the secondary transfer nip.
Untransferred toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This is cleaned by the cleaning device 10.
In the secondary transfer nip, the transfer paper P is sandwiched between the intermediate transfer belt 8 whose surface moves in the forward direction and the secondary transfer roller 19 and conveyed in the opposite direction to the registration roller pair 28 side. The On the transfer paper P sent out from the secondary transfer nip, the four-color toner image transferred to the surface is fixed by heat and pressure when passing between the rollers of the fixing device 20.
Thereafter, the transfer paper P is discharged out of the printer through the rollers of the paper discharge roller pair 29. A stack unit 30 is formed on the upper surface of the printer main body, and the transfer sheets P discharged to the outside by the discharge roller pair 29 are sequentially stacked on the stack unit 30. A bottle storage container 31 is provided below the stack portion 30 and stores toner bottles 32Y, 32M, 32C, and 32K of the respective colors.

Next, the configuration of the developing device 5Y in the process cartridge 6Y will be described mainly with reference to FIG. The developing device 5Y has a magnetic field generating means inside, a developing roller 51Y as a developer carrying member for carrying and transporting a two-component developer containing magnetic particles and toner on the surface, and the developing roller 51Y carried on the developing roller 51Y. And a doctor blade 52Y as a developer regulating member that regulates the layer thickness of the developer conveyed.
Here, a place where the developing roller 51Y is accommodated is a developing roller chamber 53Y which is a first chamber. Further, a place for storing the developer is a second agitation chamber 54Y, which is a toner conveying screw (conveying body) 55Y (first conveying screw 55Ya, first conveying screw) for agitating and conveying toner. 2 conveying screw 55Yb), a toner replenishing port 58Y for taking the toner into the stirring chamber 54Y, a partition wall 59Y between the developing roller chamber 53Y and the stirring chamber 54Y, and a communication port between the developing roller chamber 53Y and the stirring chamber 54Y ( 3).
Above the toner supply port 58Y, a shutter 71Y for closing the toner supply port 58Y and a toner supply port case 72Y provided to hold the shutter 71Y and cover the toner supply port 58Y are provided.
Reference numeral 56Y denotes a density detection sensor for detecting the toner density of the developer. When the density detection sensor 56Y detects that the toner density is insufficient in the stirring chamber 54Y, it is driven by a replenishment signal from the control unit 57Y. The toner is replenished when the motor 41Y rotates and the toner bottle 32Y (FIG. 1) rotates.
Further, the entire developing device 5Y is formed by a first member 75Y (upper case) including the inner wall of the developing roller chamber 53Y forming a developing housing and a second member 76Y (lower case) including the inner wall of the stirring chamber 54Y. ing.

FIG. 3 is a perspective view showing the structure of the developing device according to the present invention. FIG. 4 is a schematic view showing the flow of toner in the developing device of FIG. The schematic diagram showing the process cartridge for generating the Y toner image shown in FIG. 2 is a view seen from the right side of FIG. 3 in correspondence with FIG.
In FIG. 3, the upper case 75Y of FIG. 2, the toner supply port 58Y, the shutter 71Y for closing the toner supply port 58Y, the toner supply port case 72Y provided so as to cover the toner supply port 58Y, and the like are omitted.
The two-component developing device 5Y made of a magnetic carrier and toner has a toner conveying screw for agitating and conveying the replenished toner and the carrier, and this toner conveying screw is spiral for conveying in one direction. It has a shape part.
3 and 4, in this embodiment, the first transport screw 55Ya that is the toner transport screw of the developing roller chamber 53Y that is the first chamber and the toner transport screw of the stirring chamber 54Y that is the second chamber. A second transport screw 55Yb. The toner is replenished from the toner replenishing port 58Y upstream of the stirring chamber 54Y according to the consumption of the toner.
The replenished toner is mixed with the carrier in the agitating chamber 54Y, and conveyed to the downstream of the agitating chamber 54Y along the helical portion 55Yb1 of the second conveying screw 55Yb. The arrows in FIG. 4 indicate the toner conveyance direction.
In particular, as shown in FIG. 4 in which the developing roller 51Y is omitted, the partition wall 59Y between the developing roller chamber 53Y and the stirring chamber 54Y does not extend to a position crossing both ends of the developing housing, and both ends of the partition wall 59Y. And portions where the partition walls between the two ends of the developing housing are missing are provided as communication ports A and B between the developing roller chamber 53Y and the stirring chamber 54Y, respectively.

FIG. 5 is a schematic perspective view showing a stirring chamber screw pivotally supported by a bearing with a check valve. FIG. 6 is a perspective view showing a bearing with a check valve. In FIG. 5, if the spiral-shaped portion 55Yb1 simply feeds the toner downstream, the pressure of the toner conveyed to the bearing downstream of the stirring chamber screw (second conveyance screw) 55Yb is applied, and the toner leaks from a minute gap in the bearing. It will be.
For this reason, a reverse spiral-shaped portion 55Yb2 that is a reverse spiral portion in the reverse direction is provided at the downstream position of the second transport screw 55Yb. Although it is difficult to clearly understand in FIG. 5, the bearing 66 is provided with a check valve 66a as shown in FIG. 6 to prevent the toner from leaking to the outside.
In the case of the embodiment shown in FIG. 3, the second conveying screw 55Yb in the stirring chamber 54Y sends the toner to the high heat source side, and the first conveying screw 55Ya in the developing roller chamber 53Y moves to the opposite side to the drive mechanism 63. And feed the toner. Although pressure is present in both conveyance screw downstream portions, since the temperature is low in a non-driving portion without a high heat source, aggregation is difficult even if the same pressure exists.
Here, the high heat source side means the drive mechanism 63 side that receives a driving force from the image forming apparatus main body. That is, although not shown, a gear extending from a motor provided in the main body meshes with a gear of a driving mechanism 63 that is a high heat source, and the driving of the developing roller 51Y and the conveying screws 55Ya and 55Yb is driven by this gear. become. Since the gear of the driving mechanism 63 that is a source of the driving force of the developing device 5Y has a strong meshing force, the frictional heat and the like are increased, and the gear becomes a heat source having a higher temperature than other portions.

FIG. 7 is a schematic view showing a first embodiment of the elastic member according to the present invention provided downstream of the stirring chamber screw. In FIG. 7, in order to prevent the pressure of the conveyed toner from being applied to the bearing downstream of the stirring chamber screw (second conveying screw) 55Yb and to prevent the toner from leaking out from a minute gap of the bearing, for example, the Asker-F measurement is performed. Thus, the elastic member 68 having a hardness of 50 ° or less is provided in contact with the inner wall surface on the bearing side of the developing housing 76Y downstream of the second conveying screw 55Yb.
By receiving the powder pressure generated by the second conveying screw 55Yb by the elastic member 68, the pressure of the toner is relieved. The elastic member 68 may be polyurethane foam or rubber as long as it satisfies the hardness condition having elasticity with a hardness of 50 ° or less.
In this case, the surface of the elastic member 68 made of foamed polyurethane is coated to cover the foamed diameter of the foamed polyurethane. This coating suppresses clogging by the powder having a foam diameter and prevents aggregation. As a result, toner aggregation in the developing device 5Y can always be prevented, and toner can be prevented from adhering unevenly on the developing roller 51Y, which is caused by sandwiching the aggregate.
In the case of the embodiment of the developing device 5Y shown in FIG. 3, the stirring chamber screw (second transport screw) 55Yb feeds the toner to the high heat source (drive mechanism 63) side, and the first transport screw 55Ya in the developing roller chamber 53Y. Feeds toner to the side opposite to the drive mechanism 63.
Although pressure exists in both screw downstream portions, on the side where there is no high heat source, the temperature is low even in the screw downstream portion, so that aggregation is difficult to occur even if the same pressure exists. By providing the elastic member 68 according to the present invention downstream of the screw on the side where the temperature is high and the pressure is present, a great effect can be obtained by preventing toner aggregation.

FIG. 8 is a schematic perspective view showing one end in the longitudinal direction of the developing device. FIG. 9 is a schematic perspective view showing the other longitudinal end of the developing device. 8 and 9 show the right end and the left end of FIG. 3, respectively. In the present embodiment shown in FIG. 3, the drive train is on both the front side (right side) and the rear side (left side).
The front side (right side in FIG. 3) shown in FIG. 8 is a drive train for turning only the conveying screw. In the figure, the front gear 69 of the developing roller chamber screw and the front gear 71 of the stirring chamber screw are shown. Since these screws 55Ya and 55Yb have a low rotational torque, the temperature does not rise excessively.
On the other hand, the rear (left side in FIG. 3) drive train shown in FIG. 9 is on the high heat source side described above, and in addition to the developing roller chamber screw post-gear 69a, there is a developing roller gear 80 with a large torque. There is also a drive input gear 81 for inputting drive force. As a result, a temperature rise due to driving occurs.
As described above, the temperature is high and pressure is present, and in this embodiment, the bearing is contacted with the inner wall surface on the bearing side downstream of the rear side (left side) screw (first conveying screw) 55Ya, as seen in FIG. However, the elastic member 68 shown in FIG. 7 is provided. As a result, the powder pressure can be reduced at locations where the temperature and the powder pressure are high.

FIG. 10 is a schematic view showing a second embodiment of the elastic member according to the present invention provided downstream of the stirring chamber screw. In FIG. 10, the elastic member 82 is formed in a disk shape, and the outer diameter thereof is larger than the outer diameter of the reverse spiral portion 55Yb2 of the stirring chamber screw (second conveying screw) 55Yb.
The outer diameter of the elastic member 82 is made larger than the outer diameter of the agitating chamber screw 55Yb, and the toner conveying area by the agitating chamber screw 55Yb, that is, the powder pressure generating area is covered with the elastic member 82, and all of the powder pressure is covered by this elastic member. Receiving at 82, the powder pressure is relieved. Thereby, powder pressure can be reduced and aggregation can be prevented.
FIG. 11 is a schematic perspective view showing an elastic member formed in a disc shape. 12 is a schematic cross-sectional view showing the relationship between the insertion hole of the elastic member of FIG. 11 and the shaft of the stirring chamber screw. 11 and 12, the elastic member 83 is provided with an insertion hole 83a through which the shaft 55Yb3 of the stirring chamber screw 55Yb passes.
The elastic member 83 is formed of a material such as polyurethane foam having elasticity, and the elastic member 83 is bonded to the end wall of the developing housing 76Y with a double-sided tape or the like, thereby connecting the inner wall of the developing housing 76Y and the elastic member 83. It is sealed.
In this case, the inner diameter (a) of the insertion hole 83a through which the shaft 55Yb3 of the stirring chamber screw 55Yb is provided in the elastic member 83 is slightly smaller than the outer diameter (b) of the shaft 55Yb3 of the stirring chamber screw 55Yb, The shaft portion is sealed when the shaft 55Yb3 is inserted into the insertion hole 83a using elasticity. Thereby, it is possible to eliminate the need for a bearing with a check valve while maintaining the prevention of powder aggregation due to the reduction of powder pressure, and it can be constructed at low cost.

FIG. 13 is a schematic perspective view showing a stepped elastic member formed in a cylindrical shape. FIG. 14 is a schematic cross-sectional view showing the relationship between the cylindrical portion of the elastic member of FIG. 13 and the hole in the end wall of the developing housing.
13 and 14, the elastic member 84 is provided with a flange 84a, and the cylindrical portion 84b following the flange 84a is inserted into the hole 76Ya in the end wall which is an insertion hole of the developing housing 76Y. The elastic member 84 is made of a material having elasticity such as rubber.
In this case, the inner diameter (c) of the hole 76Ya of the end wall provided in the end wall of the developing housing 76Y and passing through the cylindrical portion 84b of the elastic member 84 is formed slightly smaller than the outer diameter (d) of the cylindrical portion 84b. The shaft portion is sealed when the cylindrical portion 84b is inserted into the hole 76Ya in the end wall. Thereby, it is possible to eliminate the need for a bearing with a check valve while maintaining the prevention of powder aggregation due to the reduction of powder pressure, and it can be constructed at low cost.
In the present invention, the developing device is provided as a process cartridge in which the developing device and at least the image carrier are integrated. As a result, agglomeration occurs in the developing device, and the toner flows around the developing roller, so that the toner on the developing roller is not uniform, and the toner is also non-uniform on the photosensitive drum that is an image carrier that transfers the toner from the development. I'm trying not to get it.
As a result, aggregation in the developing device is suppressed, and the toner on the developing roller is not evenly adhered to the developing roller, and the toner on the photosensitive member to which the toner is transferred from the development becomes uniform.
When the above-described developing device is mounted on the image forming apparatus, aggregation on the developing device is suppressed, and the toner on the photosensitive member that moves around the developing roller and does not cause non-uniform adhesion of the toner on the developing roller, and transfers the toner from the development. Becomes uniform. Therefore, it is possible to suppress the occurrence of white streak images caused by sandwiching of agglomerates and white-out images due to agglomeration in which the image transferred to the transfer paper is whitened along the transport direction.

1 is a schematic diagram illustrating a configuration of an electrophotographic printer. FIG. FIG. 3 is a schematic diagram illustrating a process cartridge for generating a Y toner image. FIG. 2 is a perspective view illustrating a configuration of a developing device according to the present invention. FIG. 4 is a schematic diagram illustrating a toner flow in the developing device of FIG. 3. It is a schematic perspective view which shows the stirring chamber screw pivotally supported by the bearing with a non-return valve. It is a perspective view which shows a bearing with a non-return valve. It is the schematic which shows 1st Embodiment of the elastic member by this invention provided in the downstream of the stirring chamber screw. It is a schematic perspective view which shows the longitudinal direction end of a developing device. It is a schematic perspective view which shows the longitudinal direction other end of a developing device. It is the schematic which shows 2nd Embodiment of the elastic member by this invention provided in the downstream of the stirring chamber screw. It is a schematic perspective view which shows the elastic member formed in disk shape. It is a schematic sectional drawing which shows the relationship between the penetration hole of the elastic member of FIG. 11, and the axis | shaft of a stirring chamber screw. It is a schematic perspective view which shows the stepped elastic member formed in the cylinder shape. It is a schematic sectional drawing which shows the relationship between the cylindrical part of the elastic member of FIG. 13, and the hole of the end wall of a developing housing.

Explanation of symbols

  1Y image carrier (photosensitive drum), 5Y developing device, 6Y process cartridge, 51Y developing roller, 53Y first chamber, 54Y second chamber, 55Ya toner conveying screw (first conveying screw), 55Yb toner conveying screw ( (Second conveying screw), 55Yb3 shaft, 68 elastic member, 76Y developing housing (lower case), 76Ya end wall hole (insertion hole), 82 elastic member, 83 elastic member, 83a insertion hole, 84 elastic member, 84b cylindrical Part, 100 printer (image forming apparatus)

Claims (9)

  In a developing device having a conveying screw that conveys powder accommodated in the developing housing along the axial direction from upstream to downstream, an elastic member is provided on a bearing-side inner wall surface of the developing housing downstream of the conveying screw. A developing device characterized by that.   The developing device according to claim 1, wherein the elastic member has a hardness of 50 ° (Asker-F) or less.   The developing device according to claim 1, wherein the elastic member is made of polyurethane foam, and the foaming diameter of the polyurethane foam is covered by a coating process.   The developing device according to claim 1, wherein the elastic member is provided downstream of the conveying screw on a side close to a high heat source such as a driving mechanism.   The developing device according to claim 1, wherein an outer shape of the elastic member is larger than an outer diameter of the conveying screw.   6. The developing device according to claim 1, wherein an inner diameter of a shaft insertion hole provided in the elastic member is made smaller than an outer diameter of the conveying screw.   The developing device according to claim 1, wherein an outer diameter of the elastic member is larger than an inner diameter of a hole in an end wall of the developing housing.   A process cartridge comprising at least the developing device according to claim 1 and an image carrier.   9. An image forming apparatus for developing and visualizing an electrostatic latent image formed on an image carrier with toner from a developing device, wherein the process cartridge includes the developing device and the image carrier. An image forming apparatus comprising a process cartridge.

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