JP5601635B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, or a multifunction machine thereof, and a developing device and a process cartridge installed therein, and more particularly, on a developer carrier. The present invention relates to a developing device, a process cartridge, and an image forming apparatus in which a developer regulating member that regulates the amount of developer is installed.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a developer carrying member (development) is stored in a developing device that contains a two-component developer composed of toner and a carrier (including the case where an additive is added). A technique of installing a developer regulating member that regulates the amount of developer carried on a roller is known (for example, see Patent Document 1).

In a developing device using a two-component developer, toner is appropriately replenished into the developing device from a toner replenishing port provided in a part of the developing device according to toner consumption in the developing device. The replenished toner is agitated and mixed together with the developer in the developing device by a conveying member (agitating member) such as a conveying screw. Part of the stirred and mixed developer is supplied to a developing roller (developer carrier). The developer carried on the developing roller is regulated to an appropriate amount by a doctor blade (developer regulating member, development doctor), and then the toner in the two-component developer is opposed to the photosensitive drum (image carrier). To adhere to the latent image on the photosensitive drum.
In such a developing device, the doctor blade (developer regulating member) is held on the case member (developing casing) so that the doctor gap (the gap between the developing roller and the doctor blade) can be adjusted.

  On the other hand, in Patent Document 1 and the like, the central portion in the longitudinal direction of the developing doctor (developer regulating member, doctor blade) is bent by the pressure generated when the developer carried on the developing roller passes through the position of the doctor gap. In order to prevent such a problem, a technique for disposing a deformation suppressing member that holds the developing doctor on the developing casing through the through hole formed in the developing doctor and straddling the developing doctor and the developing casing (case member) is disclosed. Has been.

  In conventional developing devices, the doctor blade and the case member together with the case member when the operating environment temperature or the in-machine temperature fluctuates due to the difference in coefficient of linear expansion between the doctor blade (developer regulating member) and the case member that holds it. The doctor gap may change in the longitudinal direction and the doctor gap may change.

  Specifically, the doctor blade needs to be formed of a high-hardness material such as stainless steel having a certain degree of hardness so as not to be worn out by the developer passing through the doctor gap. In order to easily release the heat of the doctor blade to the outside, it is often formed of a highly heat conductive material such as aluminum. In this way, because the doctor blade is held by the case member made of different materials, the doctor blade and the case member are longitudinally moved together with the case member due to the difference in the linear expansion coefficient between the members when the operating environment temperature or the in-machine temperature fluctuates. The doctor gap may become uneven in the longitudinal direction. In such a case, the amount of developer that passes through the position of the doctor gap also changes, so that the image density in the output image is excessive or insufficient, or the toner is scattered from the developing device, etc. Has occurred.

  The present invention has been made to solve the above-described problems. When the use environment temperature or the in-machine temperature fluctuates, the developer regulating member is not likely to be bent in the longitudinal direction together with the case member. An apparatus, a process cartridge, and an image forming apparatus are provided.

A developing device according to a first aspect of the present invention is a developing device that stores a developer and develops a latent image formed on an image carrier, and faces the image carrier. A developer carrying member carrying a developer, a developer regulating member facing the developer carrying member and regulating the amount of the developer carried on the developer carrying member; and the developer regulating member A case member for isolating the inside and the outside of the apparatus and holding the member in close contact with the case member, and having a linear expansion coefficient lower than that of the material forming the case member A restricting member made of a material for restricting thermal deformation of the case member , wherein the restricting member has at least two of a plurality of surfaces extending in a longitudinal direction in surface contact with the case member. Installed Those were.

  According to a second aspect of the present invention, there is provided the developing device according to the first aspect of the present invention, wherein the regulating member has a plate shape in which at least one bent portion is formed so as to be parallel to the longitudinal direction. It is a member.

  The developing device according to a third aspect of the present invention is the developing device according to the second aspect, wherein the regulating member is formed with one bent portion, and the bent portion is a short direction of the case member. It is installed so as to be located near the center.

According to a fourth aspect of the present invention, there is provided the developing device according to any one of the first to third aspects, wherein the regulating member is one of the at least two surfaces in surface contact with the case member. One surface is fixed to the case member by screw fastening at a plurality of locations in the longitudinal direction.

The developing device according to a fifth aspect of the present invention is the developing device according to any one of the first to third aspects, wherein the regulating member is one of the at least two surfaces that are in surface contact with the case member. A plurality of surfaces are fixed to the case member by screw fastening at a plurality of locations in the longitudinal direction.

According to a sixth aspect of the present invention, in the developing device according to the fourth or fifth aspect, the regulating member is formed with at least one bent portion so as to be parallel to the longitudinal direction. The plate-shaped member is formed such that the longitudinal ranges of the plurality of locations that are screwed to the case member are positioned within the longitudinal range in which the bent portion is formed. .

A developing device according to a seventh aspect of the present invention is the developing device according to any one of the first to sixth aspects, wherein the regulating member is held by the case member on the outside of the device. It is.

The developing device according to an eighth aspect of the present invention is the developing device according to any one of the first to seventh aspects, wherein the regulating member is formed of a nonmagnetic metal material.

A developing device according to a ninth aspect of the present invention is the developing device according to any one of the first to eighth aspects, wherein the developer regulating member is bent so as to be parallel to the longitudinal direction. Is a plate-like member formed with at least one, and is held in close contact with the case member.

The developing device according to a tenth aspect of the present invention is the developing device according to any one of the first to ninth aspects, wherein the developer regulating member is based on a linear expansion coefficient of a material forming the case member. Are formed of a material having a low linear expansion coefficient.

The developing device according to an eleventh aspect of the present invention is the developing device according to any one of the first to ninth aspects, wherein the developer regulating member has a linear expansion coefficient of a material forming the case member. On the other hand, it is formed of a material having an equivalent linear expansion coefficient.

A process cartridge according to a twelfth aspect of the present invention is a process cartridge that is detachably attached to the main body of the image forming apparatus, and the developing device according to any one of the first to eleventh aspects. And the image carrier.

According to a thirteenth aspect of the present invention, an image forming apparatus includes the developing device according to any one of the first to eleventh aspects and the image carrier.

  In the present application, the “process cartridge” refers to a charging unit that charges the image carrier, a developing unit (developing device) that develops a latent image formed on the image carrier, and a cleaning on the image carrier. At least one of the cleaning units and the image carrier are defined as a unit that is integrated and detachably installed on the image forming apparatus main body.

  Further, in the present application, the “longitudinal direction” is defined as a direction that coincides with the rotation axis direction of the developer carrier or the image carrier. Further, the “short direction” is defined as a direction orthogonal to the “longitudinal direction”.

  In the present invention, since the regulating member made of a material having a lower linear expansion coefficient than that of the case member is held in close contact with the case member, when the use environment temperature or the in-machine temperature fluctuates, the developer regulating member is It is possible to provide a developing device, a process cartridge, and an image forming apparatus that are unlikely to be bent in the longitudinal direction together with the case member.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged view showing a process cartridge installed in the image forming apparatus of FIG. 1. It is an enlarged view which shows a developing device. It is sectional drawing which looked at the circulation path in a developing device to the longitudinal direction. It is a schematic sectional drawing which shows the Y1-Y1 cross section in the circulation path | route of FIG. It is a schematic sectional drawing which shows the Y2-Y2 cross section in the circulation path | route of FIG. FIG. 5 is a diagram illustrating a state in which a wavy bias is generated in the developer in the circulation path of FIG. 4. It is a top view which shows the vicinity of an upper case. It is a graph which shows an experimental result. It is an enlarged view which shows the developing device of another form. It is a graph which shows another experimental result.

Embodiment.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus in the embodiment will be described with reference to FIG.
The writing units 2A to 2D are devices for writing an electrostatic latent image on the photosensitive drum 21 (image carrier) after the charging process based on image information. The writing units 2A to 2D are optical scanning devices using polygon mirrors 3A to 3D, optical elements 4A to 4D, and the like. An LED array can be used as the writing unit instead of the optical scanning device.
The paper feed unit 61 stores a transfer material P such as recording paper or OHP, and feeds the transfer material P toward the transfer belt 30 during image formation.

The transfer belt 30 is an endless belt for transferring the toner image formed on the photosensitive drum 21 onto the transfer material P by electrostatically attracting and transferring the transfer material P to the surface thereof. A suction roller 64 and a belt cleaner 65 are provided on the outer peripheral surface.
The transfer roller 24 that faces the photosensitive drum 21 via the transfer belt 30 includes a cored bar and a conductive elastic layer that covers the cored bar. The conductive elastic layer of the transfer roller 24 is prepared by blending and dispersing a conductive agent such as carbon black, zinc oxide or tin oxide in an elastic material such as polyurethane rubber or ethylene-propylene-diene polyethylene (EPDM). It is an elastic body whose (volume resistivity) is adjusted to medium resistance.

The fixing unit 66 includes a heating roller 68 and a pressure roller 67 and fixes the toner image on the transfer material P to the transfer material P by pressure and heat.
The four process cartridges 20Y, 20C, 20M, and 20BK arranged in the vertical direction along the transfer belt 30 are for forming toner images of yellow, cyan, magenta, and black, respectively.

On each of the process cartridges 20Y, 20C, 20M, and 20BK, an agent cartridge as a supply unit that supplies a carrier (magnetic carrier) and toner (toner particles) of each color (yellow, cyan, magenta, black) to the developing device 23. 28Y, 28C, 28M, and 28BK are installed.
The process cartridges 20Y, 20C, 20M, and 20BK and the agent cartridges 28Y, 28C, 28M, and 28BK can be attached to and detached from the apparatus main body 1 by opening the transfer belt 30 around the rotation support shaft.

  The image forming apparatus according to the present embodiment is a composite image forming apparatus that functions as a copying machine and a printer. When functioning as a copying machine, the image information read from the scanner is subjected to various image processing such as A / D conversion, MTF correction, gradation processing, etc., and converted into writing data. In the case of functioning as a printer, image processing is performed on image information in a format such as a page description language or a bitmap transmitted from a computer or the like, and converted into write data.

  At the time of image formation, exposure light corresponding to the image information of black, magenta, cyan, and yellow is irradiated from the writing units 2A to 2D to the process cartridges 20BK, 20M, 20C, and 20Y, respectively. That is, exposure light (laser light) emitted from each light source passes through the polygon mirrors 3A to 3D, the optical elements 4A to 4D, and is irradiated onto each photosensitive drum 21. Thus, a toner image corresponding to the exposure light is formed on the photosensitive drum 21 (image carrier) of each process cartridge 20BK, 20M, 20C, 20Y. The toner image is transferred to the transfer material P.

  The material to be transferred P fed from the paper feeding unit 61 is conveyed to the position of the transfer belt 30 at the timing of the registration roller 63 and the timing. The suction roller 64 disposed at the feeding position of the transfer belt 30 causes the transfer belt 30 to suck the material to be transferred P fed by voltage application. As the transfer belt 30 travels in the direction of the arrow, the transfer material P moves sequentially through the positions of the process cartridges 20Y, 20C, 20M, and 20BK, and the toner images of the respective colors are superimposed and transferred.

  The material P to which the color toner image is transferred is separated from the transfer belt 30 and reaches the fixing unit 66. The toner image on the transfer material P is fixed on the transfer material P by being heated while being sandwiched between the heating roller 68 and the pressure roller 67. On the other hand, the surface of the transfer belt 30 after the transfer material P is separated reaches the position of the belt cleaner 65, and dirt such as toner adhering to the surface is cleaned.

Next, the process cartridge and the agent cartridge in the image forming apparatus will be described in detail.
The process cartridges 20Y, 20C, 20M, and 20BK have substantially the same structure, and the agent cartridges 28Y, 28C, 28M, and 28BK have substantially the same structure. The alphabet (Y, C, M, BK) is removed for illustration. In addition, the writing unit is illustrated by removing the alphabet (A to D).

  FIG. 2 is an enlarged view showing the process cartridge 20 and the agent cartridge 28 installed in the apparatus main body 1. FIG. 3 is an enlarged view showing the developing device 23 installed in the process cartridge 20. 4 is a cross-sectional view of the circulation path in the developing device 23 as viewed from the direction of the arrow X shown in FIG. 3 in the longitudinal direction. FIG. 5 is a cross-sectional view showing a Y1-Y1 cross section of the circulation path in the developing device 23 of FIG. 6 is a cross-sectional view showing a Y2-Y2 cross section of the circulation path in the developing device 23 of FIG.

As shown in FIG. 2, the process cartridge 20 includes a photosensitive drum 21 as an image carrier, a charging unit 22, a developing device 23 (developing unit), and a cleaning unit 25, and is a premix developing unit. System (development system in which carrier is replenished / discharged as appropriate) is adopted.
The photosensitive drum 21 as an image carrier is a negatively charged organic photosensitive member, and is rotationally driven counterclockwise by a rotation driving mechanism (not shown).

The charging unit 22 is a charging roller having elasticity, in which a medium-resistance foamed urethane layer in which a urethane resin, carbon black as conductive particles, a sulfurizing agent, a foaming agent, and the like are formed in a roller shape on a core metal. The material of the middle resistance layer of the charging unit 22 is urethane, ethylene-propylene-diene polyethylene (EPDM), butadiene acrylonitrile rubber (NBR), silicone rubber, isoprene rubber, etc. It is also possible to use a rubber material in which a conductive material such as the above is dispersed or a foamed material of these materials.
The cleaning unit 25 is provided with a cleaning brush (or cleaning blade) that is in sliding contact with the photosensitive drum 21, and mechanically removes and collects untransferred toner on the photosensitive drum 21.

  In the developing device 23, two developing rollers 23a1 and 23a2 as developer carrying members are disposed so as to be close to the photosensitive drum 21, and the photosensitive drum 21 and the magnetic brush are in contact with each other at both opposing portions. A development area is formed. In the developing device 23, a developer G (two-component developer) composed of toner T and carrier C is accommodated. The developing device 23 develops the electrostatic latent image formed on the photosensitive drum 21 (forms a toner image). The configuration and operation of the developing device 23 will be described in detail later.

Here, the developing device 23 in the present embodiment is of a premix developing system, and a new carrier C (developer G) is appropriately supplied from the agent cartridge 28 into the developing device 23 and deteriorated. The developer G thus discharged is discharged toward the agent storage container 70 installed outside the developing device 23.
Referring to FIG. 2, the agent cartridge 28 accommodates developer G (toner T and carrier C) to be supplied into the developing device 23 therein. The agent cartridge 28 functions as a toner cartridge that supplies new toner T to the developing device 23, and also functions as a supply unit that supplies new carrier C to the developing device 23. Specifically, the shutter mechanism 80 is based on the information of the toner density (the ratio of the toner in the developer G) detected by the magnetic sensor 26 (see FIG. 4) installed in the developing device 23. The developer G is appropriately supplied from the agent cartridge 28 serving as a supply unit into the developing device 23.
In the present embodiment, the mixing ratio (toner concentration) of the toner T with respect to the carrier C in the developer G of the agent cartridge 28 is set to be relatively high.

  The supply pipe 29 serving as a supply means is for reliably guiding the developer G (toner T and carrier C) supplied from the agent cartridge 28 into the developing device 23. That is, the developer G discharged from the agent cartridge 28 is supplied into the developing device 23 via the supply pipe 29.

Next, an image forming process performed on the photosensitive drum 21 will be described.
Referring to FIG. 2, when the photosensitive drum 21 is driven to rotate counterclockwise, first, the surface of the photosensitive drum 21 is uniformly charged at the position of the charging unit 22. Thereafter, the surface of the charged photosensitive drum 21 reaches the irradiation position of the exposure light L, and an exposure process by the writing unit 2 is performed. That is, by selectively removing the charge on the photosensitive drum 21 in accordance with the image information by irradiation with the exposure light L, a difference (potential contrast) from the potential of the non-image portion that has not been irradiated is generated, and electrostatic latent Form an image. In this exposure step, the charge generation material receives light in the photosensitive layer of the photosensitive drum 21 to generate charges, and among these holes, the holes cancel out the charged charges on the surface of the photosensitive drum 21.

Thereafter, the surface of the photosensitive drum 21 on which the latent image is formed reaches a position facing the developing device 23. The electrostatic latent image on the photosensitive drum 21 comes into contact with the magnetic brush on the developing rollers 23a1 and 23a2, and the negatively charged toner T in the magnetic brush is attached and visualized.
Specifically, the developer G pumped up by the magnetic force generated by the magnetic pole of the upper developing roller 23a1 is made into an appropriate amount by a doctor blade 23c as a developer regulating member, and then the developing region (the developing region (opposite part to the photosensitive drum 21)). This is a region where the two developing rollers 23a1 and 23a2 and the photosensitive drum 21 face each other). The carrier C spiked in the development area rubs the photosensitive drum 21. At this time, the toner T mixed with the carrier C is negatively charged due to friction with the carrier C. On the other hand, the carrier C is positively charged. A predetermined developing bias is applied to the developing rollers 23a1 and 23a2 from a power supply unit (not shown). As a result, an electric field is formed between the developing rollers 23a1 and 23a2 and the photosensitive drum 21, and the negatively charged toner T is selectively attached only to the image portion on the photosensitive drum 21 by the electric field, and the toner image. Form.

Thereafter, the surface of the photosensitive drum 21 on which the toner image is formed reaches a position facing the transfer belt 30 and the transfer roller 24. Then, the toner image on the photosensitive drum 21 is transferred onto the transfer material P conveyed to the opposite position in accordance with this timing. At this time, a predetermined voltage is applied to the transfer roller 24.
Thereafter, the transfer material P to which the toner image is transferred passes through the fixing unit 66 and is discharged from the discharge roller 69 to the outside of the apparatus.

On the other hand, the toner T (untransferred toner) remaining on the photosensitive drum 21 without being transferred to the transfer material P during the transfer process reaches a portion facing the cleaning unit 25 while remaining on the photosensitive drum 21. The untransferred toner on the photosensitive drum 21 is removed and collected by the cleaning unit 25.
Thereafter, the surface of the photosensitive drum 21 passes through a static elimination unit (not shown), and a series of image forming processes on the photosensitive drum 21 is completed.

Hereinafter, the configuration and operation of the developing device 23 will be described in detail.
Referring to FIG. 3, the developing device 23 includes developing rollers 23a1 and 23a2 as developer carriers, conveying screws 23b1 to 23b3 (auger screws) as conveying members, a doctor blade 23c as a developer regulating member, a carrier trap. A collecting roller 23k, a scraper 23m, a discharge screw 23n, an upper case 23j as a case member, a restricting plate 23r as a restricting member, and the like. Further, in the developing device 23, three developer transport portions B1 to B3 that transport the developer G to form a circulation path are formed.

  The developing rollers 23a1 and 23a2 are configured such that a sleeve formed of a nonmagnetic material such as aluminum, brass, stainless steel, or conductive resin in a cylindrical shape is rotated clockwise by a rotation driving mechanism (not shown). . In the sleeves of the developing rollers 23a1 and 23a2, a magnet for forming a magnetic field is fixed so as to cause the developer G to rise on the peripheral surface of the sleeve. The carrier C in the developer G rises in a chain shape on the sleeve so as to follow the normal magnetic field lines emitted from the magnet. The charged toner T is attached to the carrier C that is spiked in a chain shape to form a magnetic brush. The magnetic brush is transferred in the same direction (clockwise) as the sleeve by the rotation of the sleeve.

The doctor blade 23c as a developer regulating member is installed on the upstream side of the developing area, and regulates the developer on the first developing roller 23a1 to an appropriate amount.
The doctor blade 23c (developer regulating member) is a plate-like member made of a nonmagnetic metal material such as SUS316 or SUSXM7 having a plate thickness of about 2 mm, and is attached to the upper case 23j (case member) by a plurality of screws 81. Are screwed (held) (see also FIG. 8).
Specifically, the doctor blade 23c is formed with a bent portion so as to be parallel to the longitudinal direction (the direction perpendicular to the paper surface of FIG. 3). That is, as shown in FIG. 3, the doctor blade 23 c is formed into a boomerang shape (a dogleg shape) by bending. As shown in FIG. 3, the doctor blade 23c is attached to the upper case 23j by screws 81 at four locations in the longitudinal direction as shown in FIG. 8 in a state where the flat portion of the doctor blade 23c is in close contact with the flat portion of the upper case 23j. Screwed on top. Specifically, although not shown, a long hole (a long hole whose vertical direction in FIG. 8 is the long diameter direction) is formed in the doctor blade 23c at a position corresponding to the screw fastening portion. A female screw portion is formed in the case 23j. Then, the screw 81 is screwed into the female screw portion of the upper case 23j through the elongated hole of the doctor blade 23c at each screw fastening location, whereby the doctor blade 23c is held (fixed) on the upper case 23j. Will be. The doctor blade 23c is screwed to the upper case 23j while adjusting the doctor gap (the gap between the doctor blade 23c and the first developing roller 23a1) by forming a long hole in the doctor blade 23c. Can do. Also, by providing the doctor blade 23c with a bent portion, the bending strength of the doctor blade 23c is improved as compared with the case where no bent portion is provided, and the doctor blade 23c is bent by the pressure of the developer passing through the doctor gap. The problem that the doctor blade 23c is bent together with the upper case 23j due to thermal deformation is less likely to occur due to the difference in the linear expansion coefficient between the upper case 23j and the doctor blade 23c.

Here, the upper case 23j as a case member separates the inside and the outside of the developing device 23 together with other case members (lower case) constituting the developing case, and can be divided with respect to the lower case. (Removable).
Specifically, the upper case 23j is configured to hold the doctor blade 23c and cover the upper part of the first developer transport unit B1. In the present embodiment, the upper case 23j needs to easily release the heat of the developing device 23 and the doctor blade 23c to the outside, and the planar shape that holds the doctor blade 23c and the first developer conveying portion B1. Since it is necessary to form a relatively complicated shape in which opposing curved shapes and the like coexist, aluminum having high thermal conductivity and high workability (linear expansion coefficient: about 23.6 × 10 ⁻⁶ / ° C.) Is formed by.
On the other hand, the doctor blade 23c needs to be formed of a high-hardness material such as SUS316 or SUSXM7 that has a certain degree of hardness so as not to be worn out by the developer passing through the doctor gap. Therefore, in this embodiment, the doctor blade 23c is formed of a material having a linear expansion coefficient lower than that of the upper case 23j made of aluminum, and a member having a relatively large difference in linear expansion coefficient. 23c and 23j are screwed together. Therefore, when both members 23c and 23j are thermally deformed, both members 23c and 23j in the fastened state are easily bent in the longitudinal direction due to the difference in linear expansion of both members 23c and 23j. In order to suppress such problems, in the present embodiment, a restriction plate 23r as a restriction member for restricting thermal deformation of the upper case 23j (and the doctor blade 23c) is installed on the upper surface of the upper case 23j. This will be described in detail later.

In the present embodiment, as the doctor blade 23c, a magnetic metal plate such as SUS430 having a plate thickness of about 0.3 mm may be used on the surface facing the first developer transport unit B1.
Moreover, in this Embodiment, the upper case 23j as a case member was comprised so that division | segmentation (detachable) was possible with respect to another case member (lower case). On the other hand, the upper case 23j as a case member can be configured integrally with another case member (lower case).

Referring to FIG. 3, the three conveying screws 23 b 1 to 23 b 3 are each formed with a screw portion in a spiral shape on a shaft portion, and the developer G accommodated in the developing device 23 is disposed in the longitudinal direction (FIG. 2), while stirring and mixing.
The first conveying screw 23b1 as the first conveying member (one conveying member) is disposed at a position facing the developing roller 23a1 in the first developer conveying portion B1, and the developer G is horizontally disposed. The developer 23a is supplied onto the developing roller 23a1 while being conveyed (the conveyance in the left direction indicated by the white arrow in FIG. 4). In other words, the first developer transport unit B1 faces the developing roller 23a1 and supplies the developer G to the developing roller 23a1 while transporting the developer G in the longitudinal direction (the rotational axis direction of the developing roller 23a1).

The second transport screw 23b2 as the second transport member is installed in the second developer transport section B2. The second transport screw 23b2 is disposed below the first transport screw 23b1 and at a position facing the developing roller 23a2. Then, the developer G separated from the developing roller 23a2 (the developer G forcibly separated from the developing roller 23a2 by the agent separation pole after the developing step) is conveyed in the horizontal direction (indicated by a white arrow in FIG. 4). It is a left-hand conveyance.) In other words, the second developer transport unit B2 is disposed at a position below the first developer transport unit B1 and facing the developing roller 23a2, and the developer G detached from the developing roller 23a2 is disposed in the longitudinal direction. Transport in the direction.
The first transport screw 23b1 and the second transport screw 23b2 are arranged so that the rotation axis is substantially horizontal, like the developing rollers 23a1 and 23a2 and the photosensitive drum 21.

  The third transport screw 23b3 as the third transport member is installed in the third developer transport section B3. The third transport screw 23b3 is disposed obliquely with respect to the horizontal direction so as to linearly connect the downstream side of the transport path by the second transport screw 23b2 and the upstream side of the transport path by the first transport member 23b1. (See FIG. 4). The third transport screw 23b3 transports the developer G transported by the second transport screw 23b2 to the upstream side of the transport path by the first transport member 23b1, and from the downstream side of the transport path by the first transport screw 23b1. The developer G circulated through the drop path 23f is transported to the upstream side of the transport path by the first transport member 23b1 (the transport is obliquely upward to the right indicated by the white arrow in FIG. 4). In other words, the third developer transport unit B3 transports the developer G transported by the second developer transport unit B2 to the upstream side of the first developer transport unit B1, and also the first developer transport unit B1. The developer G that has reached the downstream side is transported to the upstream side of the first developer transport section B1.

A transport path (first developer transport section B1) by the first transport screw 23b1, a transport path by the second transport screw 23b2 (second developer transport section B2), and a transport path (first transport by the third transport screw 23b3). 3 developer transport section B3) is isolated from the wall.
Referring to FIG. 4, the downstream side of the second developer transport unit B2 and the upstream side of the third developer transport unit B3 communicate with each other via the first relay unit 23g. In addition, the downstream side of the third developer conveyance unit B3 and the upstream side of the first developer conveyance unit B1 are communicated with each other via the second relay unit 23h. In addition, the downstream side of the first developer transport unit B1 and the upstream side of the third developer transport unit B3 communicate with each other via a drop path 23f.

With such a configuration, a circulation path for circulating the developer G in the longitudinal direction in the developing device 23 is formed by the three developer conveying portions B1 to B3 (conveying screws 23b1 to 23b3). Here, when the developing device 23 is operated, the developer accommodated in the device flows in a state as indicated by the oblique lines in FIG. Referring to FIG. 4, in the first developer conveying section B1, the developer surface on the downstream side is lower than the upstream agent surface because part of the developer being conveyed is developed. This is because it is supplied to the roller 23a1. That is, the developer that has not been supplied to the developing roller 23a1 moves to the upstream side of the third developer conveying portion B3 via the dropping path 23f.
Note that a magnetic sensor 26 as a toner concentration sensor is installed in the third developer conveying portion B3. Then, based on the toner density information detected by the magnetic sensor 26, the developer G having a predetermined toner density is supplied from the agent cartridge 28 serving as a supply unit into the developing device 23. In the present embodiment, the toner concentration of the developer G in the developing device 23 is controlled to be 4 to 7% by weight.

4 and 5, a part of the developer G accommodated in the developing device 23 is discharged to the outside (agent storage container 70) on the wall portion of the first developer conveying portion B1. A discharge port 23d (discharge means) is provided. Specifically, the discharge port 23d is supplied with the developer G into the developing device 23 by the supply means 28 and 29, the developer amount in the device is increased, and the developer surface (upper surface) of the developer conveyed to that position. When the amount exceeds the predetermined height, the excess developer G is discharged toward the agent storage container 70. That is, the excess developer G exceeds the lower portion of the discharge port 23 d, is discharged from the discharge port 23 d, and gravity falls toward the agent storage container 70 via the discharge path 71. As described above, the carrier deteriorated by being contaminated by the base resin or the external additive of the toner T is automatically discharged to the outside of the developing unit, so that deterioration of the image quality can be suppressed even over time.
Although not shown in FIGS. 2, 4, 5, etc., a discharge screw 23 n for conveying the developer discharged from the discharge port 23 d in the horizontal direction is installed in the discharge path 71. (See FIG. 3). The discharge screw 23n rotates in the clockwise direction in FIG.

  Further, a bypass for returning a part of the developer G to the upstream side of the circulation path without passing through the position where the discharge port 23d (discharge means) is disposed in the developer circulation path in the developing device 23. A path is formed. Specifically, referring to FIG. 4 and FIG. 6, the opening 23e is the first developer transport unit B1 and upstream of the discharge port 23d (a position relatively close to the discharge port 23d). Is provided. The opening 23e serves as the inlet of the bypass path, and the outlet of the bypass path is disposed in the transport path (near the center in the longitudinal direction) by the third transport screw 23b3.

  As described above, by providing the bypass path in the developer circulation path in the developing device 23, even if the developer in the developing device has a wavy deviation or the like, the amount of developer discharged from the discharge port 23d varies. It is possible to suppress a problem that the developer exceeding the necessary amount is discharged from the developing device 23.

  FIG. 7 is a diagram illustrating a state in which the developer is wavy in the developer circulation path in the developing device 23. As described above, there is a case where a wavy deviation with a large height difference occurs in the developer circulation path. Such a wave-like bias appears remarkably immediately after the operation of the developing device 23 is started (immediately after restarting). When such a wave-like deviation occurs, conventionally, all of the developer (a developer having a height H2 in FIG. 7) located higher than the lower portion of the discharge port 23d is discharged. It was discharged from the outlet 23d. Since the developer discharged in this way is not originally intended to be discharged, if such a phenomenon occurs repeatedly, the amount of developer in the developing device 23 becomes insufficient, and the developer As a result, the deterioration state of the toner becomes unstable or the charge amount of the toner decreases, which causes problems such as a decrease in image density on the output image.

  On the other hand, in the present embodiment, since the opening 23e leading to the bypass path is provided on the upstream side of the discharge port 23d, a part of the developer located at a position higher than the lower portion of the discharge port 23d is discharged. Without being discharged from 23d, it is returned to the transport path in the third transport screw 23b3 through the opening 23e. As a result, it is possible to suppress a problem that the developer is excessively discharged from the discharge port 23d.

Here, the height of the lower portion of the opening 23e in the bypass path is configured to be higher by the height H1 than the height of the lower portion of the discharge port 23d.
As a result, of the developer at a position higher than the lower portion of the discharge port 23d, the developer for the height (H2-H1) is not discharged from the discharge port 23d, and is discharged from the third conveyance screw 23b3 through the opening 23e. It will be returned to the transport path. Accordingly, it is possible to reliably prevent the problem that the developer is excessively discharged from the discharge port 23d while maintaining the original function of the discharge unit. Here, the distance W in the longitudinal direction between the discharge port 23d and the opening 23e is preferably as short as possible.

Here, referring to FIG. 3 (not shown in FIGS. 2, 4 to 6 and the like), in the present embodiment, below the second developing roller 23a2 (downstream in the rotational direction). The carrier collecting roller 23k is installed at a position facing the photosensitive drum 21. Further, a scraper 23m is installed at a position where it abuts on the carrier collecting roller 23k.
The carrier collecting roller 23k is a cylindrical body made of stainless steel or the like in which a magnet for forming a predetermined magnetic field is fixed, and the carrier that moves (flys) from the inside of the developing device 23 and adheres to the photosensitive drum 21. It is for collecting. The carrier collecting roller 23k is driven to rotate counterclockwise in FIG. Most of the carrier collected and carried by the carrier collecting roller 23k is transferred to the developing roller 23a2 at a position facing the second developing roller 23a2, and developed at the position of the developer separating pole of the developing roller 23a2. It separates from the roller 23a2 and is collected in the second developer conveying section B2. On the other hand, the carrier remaining and carried on the carrier collecting roller 23k without moving onto the developing roller 23a2 is mechanically scraped off by the scraper 23m and collected in the second developer conveying portion B2. In this way, by installing the carrier collecting roller 23k, the carrier adhering to the photosensitive drum 21 can be collected in the developing device 23, so that the occurrence of abnormal images (firefly images, whiteout images) is suppressed. In addition, the shortage of carriers in the developing device 23 is suppressed.

In the present embodiment, the outer diameters of the developing rollers 23a1 and 23a2 are 30 mm, the linear velocity on the outer peripheral surface of the developing rollers 23a1 and 23a2 is 748 mm / second, the outer diameter of the carrier collecting roller 23k is 16 mm, and the carrier collecting The linear velocity on the outer peripheral surface of the roller 23k is 10.6 mm / second, the process linear velocity (the linear velocity on the outer peripheral surface of the photosensitive drum 21 and the conveyance speed of the transfer material P) is 440 mm / second, Is set to about.
The carrier C used in the present embodiment has a particle size of 55 μm and a saturation magnetization of about 96 emu / g. Further, the toner T used in the present embodiment has a particle size of about 6.8 μm.

Hereinafter, the configuration and operation of the developing device 23 which are characteristic in the present embodiment will be described in detail with reference to FIGS.
Referring to FIG. 3, a restriction plate 23r as a restriction member that is held in close contact with upper case 23j is installed in upper case 23j (case member) that holds doctor blade 23c (developer restriction member). Yes. The restriction plate 23r as the restriction member is made of a material having a linear expansion coefficient lower than that of the material forming the upper case 23j (in this embodiment, aluminum), and the upper case 23j. It regulates the thermal deformation of.

In the present embodiment, the regulation plate 23r (regulation member) is a nonmagnetic metal material such as SUS304 (linear expansion coefficient: about 17.3 × 10 ⁻⁶ / ° C.) having a thickness of about 1.5 mm. The formed plate-like member is screwed (held) on the upper case 23j (case member) by a plurality of screws 82 (see also FIG. 8).
Specifically, the regulation plate 23r is formed with one bent portion 23r1 so as to be parallel to the longitudinal direction (the direction perpendicular to the paper surface of FIG. 3). That is, as shown in FIG. 3, the restricting plate 23r is formed into a boomerang shape (a dogleg shape) by bending. As shown in FIG. 3, the flat plate portion of the restricting plate 23r is brought into close contact with the flat portion of the upper case 23j, and the end surface of the restricting plate 23r (the end surface corresponding to the plate thickness) is the standing portion of the upper case 23j. As shown in FIG. 8, the regulating plate 23r is screwed onto the upper case 23j by screws 82 at four locations in the longitudinal direction. Specifically, although not shown, a long hole (a long hole in which the vertical direction in FIG. 8 is the long diameter direction) is formed in the restriction plate 23r at a position corresponding to the screw fastening portion. A female screw portion is formed in the case 23j. Then, the screw 82 is screwed into the female screw portion of the upper case 23j through the long hole of the restriction plate 23r at each screw fastening location, whereby the restriction plate 23r is held (fixed) on the upper case 23j. Will be. In addition, by forming a long hole in the restriction plate 23r, two surfaces (the above-described flat plate portion and end face) extending in the longitudinal direction in the restriction plate 23r are surely brought into surface contact with the upper case 23j. In the state, the restriction plate 23r can be screwed to the upper case 23j. Referring to FIG. 8, the length of the regulating plate 23r in the longitudinal direction (the left-right direction in FIG. 8) is substantially the same as that of the upper case 23j (or slightly shorter than that). Is formed.

  As described above, in the present embodiment, the regulation plate 23r made of a material having a lower linear expansion coefficient than the upper case 23j is held in close contact with the upper case 23j. Even when the upper case 23j and the upper case 23j are formed of different materials (materials having different linear expansion coefficients), the doctor blade 23c flexes in the longitudinal direction together with the upper case 23j when the use environment temperature or the in-machine temperature changes. Trouble is less likely to occur. That is, by installing the restriction plate 23r formed of a material that hardly causes thermal deformation in the upper case 23j, the upper case 23j itself in a state where the doctor blade 23c is held is also difficult to be thermally deformed. Due to the difference in coefficient of linear expansion between the doctor blade 23c and the doctor blade 23c, the doctor blade 23c is less likely to be bent due to thermal deformation together with the upper case 23j. This makes it difficult for the doctor blade 23c to bend and the doctor gap to become non-uniform in the longitudinal direction even if the operating environment temperature or the in-machine temperature fluctuates, and the image density in the output image becomes excessive or insufficient. In addition, problems such as toner scattering from the developing device are less likely to occur.

In the present embodiment, since the bending portion 23r1 is provided on the restriction plate 23r, the mechanical strength of the restriction plate 23r itself is increased as compared with the case where the bending portion 23r1 is not provided, and the upper case 23j described above. The effect of reducing the bending due to thermal deformation between the doctor blade 23c and the doctor blade 23c is enhanced.
Further, in the present embodiment, as shown in FIG. 3, the regulating plate 23r is installed so that the bent portion 23r1 is located in the vicinity of the center of the upper case 23j in the short direction (the left-right direction in FIG. 3). Has been. With such a configuration, the regulation plate 23r functions like a large black pillar passing through the central portion of the upper case 23j, and the effect of reducing the bending due to the thermal deformation between the upper case 23j and the doctor blade 23c is increased. It will be.

  In the present embodiment, two surfaces (the above-described flat plate portion and end surface) of the plurality of surfaces extending in the longitudinal direction of the regulating plate 23r are in surface contact with the upper case 23j. Since the restriction plate 23r is fixed to the upper case 23j, the upper case 23j and the doctor described above are compared with the case where one surface (for example, only the flat plate portion described above) is in surface contact with the upper case 23j. The effect of reducing the bending due to thermal deformation with the blade 23c is enhanced.

Further, in the present embodiment, referring to FIG. 8, the longitudinal range of a plurality of locations (four locations) screwed to upper case 23j is located within the longitudinal range in which bent portion 23r1 is formed. Thus, a restriction plate 23r is formed.
In other words, the positions of the screws 82 disposed at both ends in the longitudinal direction among the four screws 82 for fastening the restriction plate 23r with respect to the positions at both ends in the longitudinal direction of the bent portion 23r1 are outside the longitudinal direction. It is not, and it is comprised so that it may become the inner side of a longitudinal direction. Specifically, with reference to the positions at both ends in the longitudinal direction of the upper case 23j, the relationships D2 <D4 and D3 <D5 are established as shown in FIG.
In this way, the regulating plate 23r extending in the longitudinal direction is fixed to the upper case 23j by screw fastening at a plurality of locations in the longitudinal direction, and the longitudinal range of the screw fastening is within the longitudinal range of the bending portion 23r1. Thus, by providing the bent portion 23r1, the effect of further reducing the bending due to the thermal deformation between the upper case 23j and the doctor blade 23c is surely exhibited.
In the present embodiment, when the length of the upper case 23j in the longitudinal direction is D1, the relationship of (D1− (D4 + D5)) / D1≈0.9 is established.

In the present embodiment, as shown in FIG. 3, the regulating plate 23 r is held by the upper case 23 j on the outer side of the developing device 23, not on the inner side of the developing device 23. As a result, the restriction plate 23r does not come into contact with the developer G flowing in the developing device 23, so that the degree of freedom of the shape of the restriction plate 23r is increased. That is, when the regulating plate 23r is held by the upper case 23j on the inner side of the developing device 23, the first conveying screw 23b1 is connected with the first conveying screw 23b1 so as not to prevent the developer conveying in the first developer conveying portion B1. Restrictions on the shape of the regulating plate 23r, such as forming the opposing surface in a curved surface, will occur.
In the present embodiment, the regulation plate 23r is formed of a nonmagnetic metal material. Thereby, a magnetic field is formed around the regulating plate 23r by the magnetic poles of the developing rollers 23a1 and 23a2, and a problem that affects the developer G flowing in the developing device 23 can be suppressed.

FIG. 9 is a graph showing the results of an experiment conducted by the inventor of the present application in order to prove the effect of installing the restriction plate 23r (restriction member) described above.
In FIG. 9, the horizontal axis indicates four conditions of Examples 1 to 3 and the comparative example, and the vertical axis indicates the variation amount of the doctor gap in each condition when the variation amount of the doctor gap in the comparative example is 100%. Indicates the ratio. That is, the smaller the doctor gap variation ratio on the vertical axis, the smaller the deflection amount of the doctor blade 23c due to temperature variation, and the smaller the doctor gap variation amount. In addition, experiment measured the doctor gap fluctuation | variation when environmental temperature was changed from 10 degreeC to 27 degreeC about all conditions.
Further, the comparative example is implemented using a conventional developing device (in which the regulating plate 23r is removed from the developing device in the present embodiment), and Example 1 is implemented using the developing device 23 in the present embodiment. Example 2 uses the developing device in this embodiment in which only one surface of the regulating plate 23r is in surface contact with the upper case 23j, and Example 3 uses the bent portion 23r1 of the regulating plate 23r in the developing device in this embodiment. Is used (a flat regulation plate), and only one surface is in surface contact with the upper case 23j.
From the experimental results of FIG. 9, it can be seen that by providing the regulating plate 23r, the amount of deflection of the doctor blade 23c due to temperature variation is reduced and the amount of change in the doctor gap is reduced. In particular, it can be seen that the effects described above can be further exerted by making the shape and installation conditions of the regulating plate 23r the same as in the present embodiment.

In the present embodiment, one bending portion 23r1 of the regulating plate 23r is provided, but two bending portions 23r1 of the regulating plate 23r may be provided as shown in FIG. In this case, the mechanical strength of the restriction plate 23r itself is further increased, and the effect of reducing the bending due to thermal deformation between the upper case 23j and the doctor blade 23c is further increased.
In the present embodiment, only one surface that is in surface contact with the upper case 23j is fixed to the upper case 23j by screw fastening at a plurality of locations in the longitudinal direction. On the other hand, referring to FIG. 10, when two bent portions 23r1 of the restricting plate 23r are provided, etc., the two surfaces (the flat plate portion and one surrounded by a broken line) are in surface contact with the upper case 23j. And the bent portion 23r1) can be fixed to the upper case 23j by screw fastening at a plurality of locations in the longitudinal direction. In this case, the degree of adhesion between the restriction plate 23r and the upper case 23j is further increased, and the effect of reducing the bending due to the thermal deformation between the upper case 23j and the doctor blade 23c is further increased.

  As described above, in the present embodiment, the regulation plate 23r (regulation member) made of a material having a lower linear expansion coefficient than the upper case 23j (case member) is held in close contact with the upper case 23j. Therefore, even when the doctor blade 23c (developer regulating member) and the upper case 23j that holds the doctor blade 23c are formed of different materials, the doctor blade 23c It is possible to make it difficult for the upper case 23j to be bent in the longitudinal direction.

In the present embodiment, the present invention is applied to the developing device 23 in which three developer conveying units B1 to B3 are installed. However, the development in which two or less developer conveying units are installed or four or more developer conveying units are installed. The present invention can also be applied to an apparatus. Even in that case, the same effect as the present embodiment can be obtained.
In the present embodiment, the third transport screw 23b3 is disposed obliquely with respect to the horizontal direction. However, the third transport screw 23b3 can be disposed horizontally.
Further, in the present embodiment, the discharge port 23d is provided in the wall portion of the first developer conveyance portion B1, but the discharge port 23d can also be provided in the wall portions of the other developer conveyance portions B2 and B3.

In this embodiment, the developer G (toner T and carrier C) is supplied from the agent cartridge 28 serving as the supply unit toward the developing device 23. However, only the carrier C is supplied from the supply unit toward the developing device 23. It can also be supplied. In that case, a toner cartridge containing only toner is installed separately from the agent cartridge (carrier cartridge), and the toner contained in the toner cartridge is appropriately directed toward the developing device 23 based on the detection result of the magnetic sensor 26. I will supply it.
Further, in the present embodiment, the present invention is applied to the premix developing type developing device 23, but a doctor blade 23c (developer regulating member) is installed even in other developing type developing devices. Naturally, the present invention can be applied to any developed developing apparatus.
Even in those cases, the same effects as in the present embodiment can be obtained.

Further, in the present embodiment, the present invention is applied to an image forming apparatus in which a part of the image forming unit is configured by the process cartridge 20. However, the application of the present invention is not limited to this, and the present invention can naturally be applied to an image forming apparatus in which the image forming unit is not formed into a process cartridge. Specifically, the present invention can naturally be applied even when the developing device 23 is configured as a unit that is detachably attached to the image forming apparatus main body.
Further, in the present embodiment, the present invention is applied to the developing device 23 in which two developing rollers 23a1 and 23a2 are installed. However, the present invention is also applied to a developing device in which one or more developing rollers are installed. Of course, the present invention can be applied. Even in that case, the same effect as the present embodiment can be obtained.

  In the present embodiment, the plate-shaped member restriction plate 23r is used as the restriction member. However, the form of the restriction member is not limited to this, and for example, a prismatic member can be used as the restriction member. In this case, the same effect as that of the present embodiment can be obtained.

In the present embodiment, the doctor blade 23c (developer regulating member) is formed of a material having a linear expansion coefficient lower than that of the material forming the upper case 23j (case member).
On the other hand, the doctor blade 23c (developer regulating member) can be formed of a material having a linear expansion coefficient equivalent to that of the material forming the upper case 23j (case member). Specifically, when the doctor blade 23c and the upper case 23j are formed of the same material (for example, when the upper case 23j is formed of SUS316 according to the material of the doctor blade 23c, or according to the material of the upper case 23j, the doctor blade 23c is made of aluminum, etc.), or when the doctor blade 23c and the upper case 23j are made of different materials having a similar linear expansion coefficient, the heat dissipation of the upper case 23j or the doctor blade 23c Although there is a possibility that the mechanical durability is lowered, when the use environment temperature or the in-machine temperature fluctuates, the problem that the doctor blade 23c bends in the longitudinal direction together with the upper case 23j is less likely to occur.
FIG. 11 is a graph showing the results of an experiment conducted by the present inventor in order to prove the effect obtained when the doctor blade 23c and the upper case 23j are formed of a material having an equivalent linear expansion coefficient. In FIG. 11, the horizontal axis shows the three conditions of Examples 4 and 5 and the comparative example, and the vertical axis shows the amount of fluctuation of the doctor gap in each condition when the amount of fluctuation of the doctor gap in the comparative example is 100%. The ratio is shown (corresponding to FIG. 9). In addition, experiment measured the doctor gap fluctuation | variation when environmental temperature was changed from 10 degreeC to 27 degreeC about all conditions.
Further, the comparative example is a fourth embodiment using a conventional developing device (the developing device in the present embodiment is the same as the comparative example in FIG. 9 except that the regulating plate 23r is removed). Is a developing device according to the present embodiment in which a doctor blade 23c and an upper case 23j are formed of SUS316 (however, a flat doctor blade without a bent portion is used). In the developing device according to the embodiment, a doctor blade 23c and an upper case 23j formed of SUS316 are used.
From the experimental results of FIG. 11 as well, by forming the doctor blade 23c and the upper case 23j with materials having the same linear expansion coefficient, the amount of deflection of the doctor blade 23c due to temperature fluctuation is reduced, and the amount of fluctuation of the doctor gap is reduced. It turns out that it becomes small. In particular, it can be seen that the above-described effects can be further exerted by making the shape and installation conditions of the doctor blade 23c the same as in the present embodiment.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 image forming apparatus body (apparatus body),
20, 20Y, 20C, 20M, 20BK Process cartridge,
21 Photosensitive drum (image carrier),
23 Developing device (developing part),
23a1, 23a2 developing roller (developer carrier),
23c Doctor blade (developer regulating member),
23j Upper case (case member),
23r regulating plate (regulating member),
23r1 bent part,
81, 82 screws,
G developer (two-component developer), T toner, C carrier.

JP 2009-175360 A

Claims (13)

A developing device for containing a developer and developing a latent image formed on an image carrier,
A developer carrying body facing the image carrying body and carrying a developer;
A developer regulating member facing the developer carrying body and regulating the amount of developer carried on the developer carrying body;
A case member for holding the developer regulating member and isolating the inside and the outside of the apparatus;
A regulating member that is held in close contact with the case member and that is made of a material having a linear expansion coefficient lower than that of the material forming the case member, and regulates thermal deformation of the case member;
Equipped with a,
The developing device according to claim 1, wherein the regulating member is installed such that at least two of the plurality of surfaces extending in the longitudinal direction are in surface contact with the case member .   The developing device according to claim 1, wherein the regulating member is a plate-like member in which at least one bent portion is formed so as to be parallel to the longitudinal direction.   The developing device according to claim 2, wherein the restricting member is formed such that one bent portion is formed and the bent portion is positioned in the vicinity of a center in a short direction of the case member. 2. The regulating member according to claim 1, wherein one of the at least two surfaces in surface contact with the case member is fixed to the case member by screw fastening at a plurality of locations in a longitudinal direction. The developing device according to claim 3. The said regulating member was fixed to the said case member by the screw fastening in the several places of a longitudinal direction among the said at least two surfaces which are in surface contact with the said case member. The developing device according to claim 3. The regulating member is
A plate-like member in which at least one bent part is formed so as to be parallel to the longitudinal direction,
6. The longitudinal direction range of the plurality of locations to be screwed to the case member is formed so as to be positioned within the longitudinal range in which the bent portion is formed. The developing device according to 1. The developing device according to claim 1, wherein the regulating member is held by the case member on the outside side of the apparatus. The developing device according to claim 1, wherein the regulating member is made of a nonmagnetic metal material. The developer regulating member is a plate-like member in which at least one bent portion is formed so as to be parallel to the longitudinal direction, and the developer regulating member is held in close contact with the case member. The developing device according to claim 1. The developer according to claim 1, wherein the developer regulating member is formed of a material having a linear expansion coefficient lower than that of a material forming the case member. apparatus. 10. The developer regulating member according to claim 1, wherein the developer regulating member is formed of a material having a linear expansion coefficient equivalent to a linear expansion coefficient of a material forming the case member. Development device. A process cartridge that is detachably installed on the main body of the image forming apparatus,
12. A process cartridge, wherein the developing device according to claim 1 and the image carrier are integrated. An image forming apparatus comprising the developing device according to claim 1 and the image carrier.

Images