JP2004045574A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of density gradient (density unevenness) by preventing torsion from arising in making a developing roller abut on a photoreceptive drum. <P>SOLUTION: The exposure optical path L of an exposure device 40 to the photoreceptive drum 5 is made nearly horizontal. A developing unit 8 is disposed on the lower side of the exposure optical path L, and also a replenishing container 30 is disposed on the upper side of the exposure optical path L. The developing roller 12 abuts on the photoreceptive drum 5 by pressing the developing unit 8 by a cam 16 on a line C connecting the center of the photoreceptive drum 5 and the center of the developing roller 12. Then, the generating line of the developing roller 12 accurately abuts on the generating line of the photoreceptive drum 5 by directly guiding the vicinity of both end pats of the developing roller 12 and also on the line C by an image forming apparatus main body, so that the occurrence of the density unevenness is prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus in which a photosensitive drum is arranged above a fixing device and an image is formed while a recording material is conveyed from below to above, a writing laser optical path of an exposure apparatus is set to be substantially horizontal, and the photosensitive path is set by this optical path. A type in which a drum is irradiated with laser light is known. In this method, the photosensitive drum and the developing device are configured as an integral type process cartridge, and a space for passing a laser beam is provided in a part of the process cartridge (for example, JP-A-06-266172). For this reason, in order to increase the toner capacity of the developing device, for example, as disclosed in Japanese Patent Application Laid-Open No. 2000-086076, a developing container having a large depth is formed below the writing laser beam path, It is necessary to provide a plurality of stirring blades and a plurality of toner conveying screws, which complicates the configuration and increases the overall size.
[0003]
On the other hand, when the photosensitive drum and the developing device are formed separately, it is necessary to bring the developing roller of the developing device into contact with the surface of the photosensitive drum, and an urging means is used for this. The urging means urges the developing container of the developing device toward the photosensitive drum, thereby bringing the developing roller into contact with the surface of the photosensitive drum. At this time, a guide member for guiding the movement of the developing device is formed on the side surface of the developing container, or a dedicated developing pressure rail is slidably formed on the image forming apparatus main body side by a sheet metal. When the rail is pressed by the pressing means and slid, the developing roller is brought into contact with the photosensitive drum via the developing device.
[0004]
[Problems to be solved by the invention]
However, according to the above-described image forming apparatus, in order to increase the toner capacity of the developing device of the process cartridge, for example, as disclosed in Japanese Patent Application Laid-Open No. 2000-086076, a large depth It is necessary to provide a plurality of agitating blades for toner transport and a plurality of toner transport screws to supply the toner of the developing roller, and the number of parts is large, the configuration is complicated, and the overall size is increased. Would. Further, since the process cartridge has a large number of parts, there is a possibility that at the time of replacement, a usable member which has not reached the end of its life and which can be used will be replaced.
[0005]
On the other hand, when the photosensitive drum and the developing device are configured separately to simplify the configuration, the bus of the developing roller of the developing device is accurately abutted against the bus of the photosensitive drum without twisting. It is difficult. When this precision is reduced, a density gradient is generated along the generating line.
[0006]
In view of the above, according to the present invention, the developing device is formed separately from the photoconductor, the configuration of the developing device is simplified, and the occurrence of a density gradient is prevented by accurately contacting the developing roller with the photoconductor. It is an object of the present invention to provide an image forming apparatus as described above.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 includes an exposure unit having a substantially horizontal exposure optical path, exposing a charged image carrier surface via the exposure optical path to form an electrostatic image, and Developing means for developing the electrostatic image with toner, transfer means for transferring the toner image on the image carrier to a recording material, and fixing the toner image on the recording material disposed above the image carrier and the transfer means An image forming apparatus comprising: a developing container arranged below the exposure light path to store toner; and a developing container arranged above the exposure light path to store toner. A replenishing container for replenishing the developing container, the developing container includes a developing rotator that is arranged along the generatrix of the image carrier and carries and transports the toner, and a developing rotator that is disposed substantially in parallel with the developing rotator. The supplied toner is supplied to the developing rotating body. Having a conveying member for conveying I, characterized in that.
[0008]
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, a rotating shaft substantially parallel to the developing rotator and the transport member and a flexible sheet rotated by the rotating shaft are provided. A toner agitating member having the toner agitator is provided on the developing container, and the rotation axis is disposed between a center of the developing rotator and a center of the transporting member in a horizontal position, and a rotating shaft of the developing rotator in a vertical position. The toner stirring member is disposed so as to be disposed below a center and a center of the transport member.
[0009]
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the developing container has a first horizontal portion that is substantially horizontal below the developing rotator, and is substantially below the conveying member. It has a horizontal second horizontal portion, and has a concave portion below the toner stirring member and continuous with the first and second horizontal portions.
[0010]
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the concave portion has a bottom portion having a radius smaller than a locus of a leading end of the flexible sheet accompanying rotation of the toner stirring member. It is characterized by.
[0011]
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the developing container is urged toward the image carrier to move the developing rotary body to the image carrier. And a biasing means for biasing the developing container on a straight line connecting the center of the image bearing member and the center of the developing rotator.
[0012]
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the image forming apparatus further includes an image forming apparatus main body to which the developing container is mounted, and the image forming apparatus main body is configured to move the developing container by the urging member. When biasing toward the image carrier, the first and second guides for guiding the developing rotator along a line connecting the center of the image carrier and the center of the developing rotator are rotated by the developing rotation. It is provided near both ends in the longitudinal direction of the body.
[0013]
According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, a magnet roller is provided inside the developing rotator, and the first guide portion is configured to freely rotate an axis of the developing rotator. It guides a rolling bearing to be supported, and the second guide part guides a supporting member that supports the shaft of the magnet roller so that it cannot rotate.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the components denoted by the same reference numerals have the same configuration or operation, and a repeated description thereof will be omitted as appropriate.
[0015]
<Embodiment 1>
FIG. 1 shows a schematic configuration of an image forming apparatus according to Embodiment 1 as an example of the image forming apparatus according to the present invention. The image forming apparatus shown in the figure is an electrophotographic laser beam printer, and the figure is a longitudinal sectional view showing a schematic configuration thereof.
[0016]
A laser beam printer (hereinafter, referred to as an “image forming apparatus”) illustrated in FIG. 1 includes an image forming unit 1 that forms an image on a recording material P (for example, paper, a transparent film), and a recording material P that is stored and one by one. The image forming apparatus includes a recording material transporting unit 2 for supplying the image forming unit 1, a reader scanner unit 3 for reading an image of a document, and a recording material discharging unit 4 for discharging the recording material P after image formation.
[0017]
The image forming section 1 includes a drum-type electrophotographic photosensitive member (hereinafter, referred to as “photosensitive drum”) 5 as an image carrier. Around the photosensitive drum 5, a primary charging roller (charging means) 6 for uniformly charging the surface of the photosensitive drum 5 substantially in the rotation direction (counterclockwise), and exposing the charged surface of the photosensitive drum 5. Exposure device (exposure means) 40 for forming an electrostatic latent image by applying toner to developing device (developing means) 8 for attaching toner to the electrostatic latent image to develop it, For example, a transfer roller (transfer means) 9 for transferring to a paper or a transparent film), a separation charger 10 for separating the recording material P after the transfer of the toner image from the surface of the photosensitive drum 5, and cleaning the surface of the photosensitive drum 5 after the transfer of the toner image A cleaning device (cleaning means) 7 for cleaning is provided. Further, on the downstream side (upper side) of the photosensitive drum 5 along the conveying direction of the recording material P, a fixing device (fixing means) 11 for melting and fixing the toner image on the surface of the recording material P is provided.
[0018]
The recording material transporting unit 2 includes paper feeding cassettes 21 and 22 for storing the recording material P, paper feeding rollers 23 a and 23 b for feeding the recording material P from the paper feeding cassettes 21 and 22, and a recording material P fed by one. Separating / conveying rollers 24a, 24b, which are fed out downstream one by one, conveying rollers 25a, 25b, 25c, and a resist for supplying the conveyed recording material P to a transfer section between the photosensitive drum 5 and the transfer roller 9 at a predetermined timing. A roller 26a is provided.
[0019]
The reader scanner unit 3 includes the following members (all not shown). As each member, a platen glass on which a document is placed, a platen plate rotatably provided above the platen glass, a document reading plate arranged in the image forming apparatus main body below the platen glass. A first mirror base having a light source and a first mirror, two optical path bending mirrors arranged at 90 degrees, a second mirror base for bending light rays from the first mirror in substantially opposite directions, and collecting light rays from the second mirror base. Examples include a lens that emits light, a CCD that photoelectrically converts a light beam from the lens, and the like.
[0020]
The recording material discharge unit 4 is disposed above the image forming unit 1 and below the reader scanner unit 3 and includes a space surrounded by a wall surface of the image forming apparatus main body (hereinafter, referred to as a “body space”). Have been. The recording material P on which the toner image is fixed on the surface in the image forming unit 1 is discharged to the recording material discharge unit 4 by the transport roller 25d and the discharge roller 26b.
[0021]
Next, the overall operation of the image forming apparatus having the above configuration will be described.
[0022]
The photosensitive drum 5 is driven to rotate at a predetermined process speed (peripheral speed) in the direction of the arrow by a driving unit (not shown), and the surface thereof is uniformly charged to a predetermined polarity and potential by the primary charging roller 6. The charged photosensitive drum 5 is exposed by the exposure device 40. The exposure device 40 exposes the surface of the photosensitive drum 5 with a laser beam that is turned on / off in accordance with image information read by the reader scanner unit 3. As a result, the charge on the exposed portion is removed, and an electrostatic latent image on the surface of the photosensitive drum 5 is formed. The electrostatic latent image is developed as a toner image by attaching toner by the developing device 8. In the present invention, the exposure light path L of the laser light (exposure light) is configured to be substantially horizontal.
[0023]
The toner image thus formed on the photosensitive drum 5 is transferred to the recording material P supplied from the sheet cassette 21 or 22. The recording material P stored in the paper feed cassette 21 or the paper feed cassette 22 is fed by a paper feed roller 23a or a paper feed roller 23b, and is separated one by one by a separation / conveyance roller 24a or a separation / conveyance roller 24b. The sheet is conveyed to registration rollers 26a by 25a, 25b, 25c and the like. The recording material P conveyed to the registration roller 26a is temporarily stopped here, and is supplied to the transfer unit at a timing corresponding to the toner image on the photosensitive drum 5. The toner image on the photosensitive drum 5 is transferred by the transfer roller 9 to the recording material P supplied to the transfer unit.
[0024]
After the transfer of the toner image, the toner remaining on the surface of the photosensitive drum 5 (residual toner) is removed by the cleaning blade 7a of the cleaning device 7, and is used for the next image formation.
[0025]
On the other hand, the recording material P after the transfer of the toner image is separated from the surface of the photosensitive drum 5 by the separation charger 10, and is conveyed to the fixing device 11 along the conveyance guide 10a. The recording material P is heated and pressed by the fixing roller and the pressure roller of the fixing device, and the toner image is transferred to the surface. The recording material P after the transfer of the toner image is conveyed by the conveying roller 25d, and is further discharged to the recording material discharge unit 4 by the discharge roller 26b. Thus, the image formation on one recording material P is completed.
[0026]
The above-described image forming apparatus functions as a copier, a printer, and a facsimile. That is, when the exposure device 40 irradiates a laser beam based on the image of the document read by the reader scanner unit 3 from the exposure device 40, it functions as a copier, and inputs image data and print commands from a computer (not shown) or the like. When the exposure device 40 emits a laser beam based on image data, the exposure device 40 functions as a printer, and further receives facsimile image data from another terminal (not shown) via a telephone line or the like, and When irradiating the laser beam based on the data from the exposure device 40, it functions as a facsimile receiver.
[0027]
Next, the developing device 8 will be described in detail with reference to FIGS.
[0028]
FIG. 2 is a longitudinal sectional view showing a state where the developing device 8 is separated from the photosensitive drum 5 from the state of FIG. 1, and FIG. 3 shows a positioning structure on the near side of the developing device (the front side of the image forming apparatus). FIG. 4 is a diagram showing a positioning structure on the back side of the developing device (the back side of the image forming apparatus), and FIG. 5 is a diagram showing a horizontal section of the developing device as viewed from above.
[0029]
The developing device 8 includes a developing container 20 in which a developer (toner) is stored, a developing roller (developing rotator) 12 rotatably supported by the developing container 20, and a magnet disposed inside the developing roller 12. A roller (however, a magnet roller has a shaft 12e having a D-shaped cross section in FIG. 3), a regulating blade 13, a transport screw (transport member) 15, and a stirring member (toner stirring member) 14 And The entire developing container 20 is disposed below the exposure light path L and between the photosensitive drum 5 and the exposure device 40. The replenishing container 30 for replenishing the developing device 8 with toner is disposed above the exposure optical path L.
[0030]
The developing container 20 is formed to be long along the axial direction (general line direction) of the photosensitive drum 5. The developing container 20 has a substantially horizontal first horizontal portion 8 a below the developing roller 12, has a substantially horizontal second horizontal portion 8 b below the conveying screw 15, and has a flat stirring member 14. A lower part has a concave portion 8c continuous with the first and second horizontal portions 8a and 8b. Further, the concave portion 8c has a bottom portion whose radius is smaller than the locus of the tip of the flexible sheet 14b (described later) accompanying the rotation of the stirring member 14. An inclined wall 17 is provided near the boundary between the second horizontal portion 8b and the concave portion 8c. The inclined wall 17 controls the amount of drop of the toner conveyed in the axial direction by the conveying screw 15 (described later) together with the second horizontal portion 8b. The above-mentioned first horizontal portion 8a is for increasing the contact area between the developing roller 12 and the toner.
[0031]
The developing container 20 is provided with a rib 8d outside the recess 8c. The rib 8d is guided by a guide stay 19 having a substantially V-shaped cross section provided on the image forming apparatus main body side. One surface 19a of the guide stay 19 is formed parallel to the line C described above. Therefore, when the developing device 8 is urged by the cam 16 described later and moves toward the photosensitive drum 5, it can move along the line C with high accuracy.
[0032]
The guide stay 19 is provided with a cam 16 as an urging member. As shown in FIGS. 3 and 4, the cam 16 has a rotation center 16b, and is further urged by a compression spring 16a toward a side far from the rotation center 16b. The cam 16 can take a standby position indicated by a dotted line in FIGS. 3 and 4 and an urging position indicated by a solid line. The developing device 8 is set on the guide stay 19 when the cam 16 is located at the standby position. In this state, the developing device 8 rotates the cam 16 clockwise by a swing angle (approximately 90 degrees) indicated by an arrow 16c. Then, the cam 16 arranged at the urging position urges the developing device 8 toward the photosensitive drum 5 via the rib 8d. The contact portion T between the rib 8d and the cam 16 at this time is located on a line C connecting the center 5a of the photosensitive drum 5 and the center of the developing sleeve 12. Note that the cams 16 may be provided at at least two places along the longitudinal direction of the developing device 8. Further, it is preferable that these cams are connected by a shaft so that they operate simultaneously.
[0033]
As shown in FIG. 5, the developing roller 12 is rotatably supported by the developing container 20 in the vicinity of both ends in the longitudinal direction with an appropriate play. In the vicinity of both ends of the developing roller 20, butting rollers 12h, 12h are provided. The abutment rollers 12h have an outer diameter slightly larger than the outer diameter of the developing roller 20, and the developing device 8 is biased toward the photosensitive drum 5 by a cam (biasing member) 16 described later. The abutting rollers 12h, 12h are brought into contact with the surface of the photosensitive drum 5 so that a minute gap is provided between the surface of the photosensitive drum 5 and the surface of the developing roller 12. Charging is performed through the minute gap. Gears 12d and 12c are fixed to the shaft of the developing roller 12 outside the butting roller 12h on the inner side (upper side in FIG. 5). The power of a motor (not shown) provided in the image forming apparatus main body is transmitted to the developing roller 12 via a developing roller input gear 12g and a gear 12c. Further, this power is transmitted to the stirring member driving gear 14c and the conveying screw driving gear 15a via the gear 12d and the idle gear in FIG. 5, so that the stirring member 14 is moved in the same direction as the developing roller 12 and conveyed. The screw 15 is driven to rotate in a direction opposite to that of the developing roller 12.
[0034]
A bearing 12b as a rolling bearing is fixed to an end of the shaft of the developing roller 12 on the inner side of the shaft. When the developing roller 12 comes into contact with the photosensitive drum 5, the bearing 12 b is directly moved by a first guide portion 51 (see FIGS. 4 and 5) provided on a rear plate 53 of the image forming apparatus main body. Guide The first guide portion 51 is provided so as to protrude from the rear plate 53 and has a regulating portion 51a having a width substantially equal to the outer diameter of the bearing 12b on the side near the center of the photosensitive drum 5 as shown in FIG. In addition, the photosensitive drum 5 has an enlarged portion 51b on the side farther from the center than the photosensitive drum 5 has a wider width. The restricting portion 51a is formed such that the center of the bearing 12b, that is, the center of the developing roller 12, moves on a line C connecting the center 5a of the photosensitive drum 5 and the center of the developing roller 12.
[0035]
The magnet roller disposed inside the developing roller 12 is a roller-shaped magnet having four poles (not shown) of N1, N2, S1, and S2. As shown in FIGS. 3 and 5, the shaft 12a of the magnet roller protrudes from the end of the developing roller 12 on the near side (the lower side in FIG. 5). The shaft 12a is formed in a D shape as shown in FIG. 3, and a support member 12i is fitted to the shaft 12a. The support member 12i is integrally formed with an annular portion 12e having a through hole having the same shape as the shaft 12a on the inside, and a rod-like portion 12f extending obliquely outward from the annular portion 12e. The support member 12i is guided by a second guide portion 52 (see FIG. 3) provided in the image forming apparatus main body. The second guide portion 52 is formed in a groove shape that allows the rod-shaped portion of the support member 12i to slide smoothly. The second guide portion 52 is formed so as to coincide with a line C connecting the center of the photosensitive drum 5 and the center of the developing roller 12. The above-described magnet roller is supported by the support member 12i, thereby preventing rotation. Further, when the developing device 8 is urged toward the photosensitive drum 5 by the cam 16, the rod portion 12f of the support member 12i is moved. By moving along the second guide portion 52, the magnet roller and thus the developing roller 21 move along the line C.
[0036]
When the developing unit 8 is urged toward the photosensitive drum 5 by the cam 16, the center of the developing roller 12 is directly guided by the image forming apparatus main body, and moves along the line C. I have. That is, when the developing device 8 is urged, the developing roller 12 has a bearing 12b attached to the rear end of the shaft, and a first guide portion formed on the rear plate 53 of the image forming apparatus main body. A support member 12i, which is guided by 51 and attached to the front end of the shaft 12a of the magnet roller, is guided by the second guide portion 52 of the image forming apparatus main body. The developing roller 12 is a guide, and the contact portion T of the cam 16 is located on the line C. Therefore, the developing roller 12 is adjusted so that its generatrix accurately matches the generatrix of the photosensitive drum 5, that is, there is no twist. Be abutted. As a result, a density gradient generated when twisting occurs is effectively prevented.
[0037]
The regulating blade 13 is a plate-like member formed of a magnetic material, has a clearance of about 200 μm from the surface of the developing roller 12, and regulates the amount of toner coated on the surface of the developing roller 12. .
[0038]
The transport screw 15 is disposed substantially parallel to the developing roller 12 described above, and is disposed at substantially the same height. The transport screw 15 transports the toner supplied from the supply container 30 to the developing container 20 along the developing roller 12. The supply container 30 includes a supply port 34 having a slide shutter, a transport screw 31 that transports the toner toward the supply port 34, and a motor 32 that rotates the transport screw 31 via a drive gear 33.
[0039]
The stirring member 14 has a rotating shaft 14a substantially parallel to the developing roller 12 and the conveying screw 15, and a flexible sheet 14b rotated by the rotating shaft 14a. The rotating shaft 14a is disposed between the center of the developing roller 12 and the center of the transport screw 15 in the horizontal direction, and is located below the center of the developing roller 12 and the center of the transport screw 15 in the vertical direction. are doing. The stirring member 14 rotates the flexible sheet 14b in the direction indicated by the arrow (counterclockwise in FIG. 1) by rotating the rotation shaft 14a and rotating the flexible sheet 14b in the direction indicated by the arrow in FIG. By using the elasticity, the toner is supplied to the developing roller 12.
[0040]
Note that a toner sensor is provided between the stirring member 14 and the transport screw 15 in the developing container 20. Based on the output of the toner sensor, the slide shutter of the supply port 34 of the supply container 30 is opened and closed to adjust whether toner is supplied to the developing device 8.
[0041]
【The invention's effect】
As described above, according to the present invention, the developing device is configured separately from the photoconductor, the configuration of the developing device is simplified, and the developing roller is brought into contact with the photoconductor with high accuracy to achieve the density gradient. Can be prevented from occurring.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a state in which a developing unit is in contact with a photosensitive drum in the image forming apparatus according to the first embodiment.
FIG. 2 is a longitudinal sectional view illustrating a state in which a developing unit is separated from a photosensitive drum in the image forming apparatus according to the second embodiment;
FIG. 3 is a diagram showing a positioning structure on the near side of the developing device (the front side of the image forming apparatus).
FIG. 4 is a diagram illustrating a positioning structure on the back side of the developing device (the back side of the image forming apparatus).
FIG. 5 is a view of a horizontal section of the developing device as viewed from above.
[Explanation of symbols]
5 Image carrier (photoreceptor, photosensitive drum)
6 Charging means (primary charging roller)
8 Developing means (developing device, developing device)
8a first horizontal portion 8b second horizontal portion 8c recess 9 transfer means (transfer roller)
11 Fixing device (fixing device)
12 Developing rotating body (developing roller)
12b Rolling bearing (bearing)
12i Supporting member 14 Toner stirring member (stirring member)
14a Rotating shaft 14b Flexible sheet 15 Conveying member (conveying screw)
16 biasing means (cam)
20 developing container 30 replenishing container 40 exposure means (exposure device)
51 First guide part 52 Second guide part C Line L connecting the center of the photoconductor and the center of the developing roller Exposure optical path (optical path of laser light)
P recording material

Claims (7)

An exposure unit having a substantially horizontal exposure optical path, exposing a charged image carrier surface through the exposure optical path to form an electrostatic image, and developing the electrostatic image on the image carrier with toner An image comprising: developing means; transfer means for transferring the toner image on the image carrier to a recording material; and a fixing device disposed above the image carrier and the transfer means for fixing the toner image on the recording material. A forming device,
The developing means includes a developing container arranged below the exposure light path to store toner, and a supply container arranged above the exposure light path to supply toner to the developing container,
The developing container includes a developing rotator disposed along the generatrix of the image carrier to carry and transport toner, and a developing rotator disposed substantially in parallel with the developing rotator to supply toner supplied from the supply container. And a conveying member for conveying along the
An image forming apparatus comprising: A toner agitating member having a rotation axis substantially parallel to the developing rotator and the transport member and a flexible sheet rotated by the rotation axis is provided in the developing container,
The rotation axis is disposed between a center of the developing rotator and a center of the transporting member for a horizontal position, and is lower than a center of the developing rotator and a center of the transporting member for a vertical position. Disposing the toner stirring member so as to be disposed;
The image forming apparatus according to claim 1, wherein: The developing container has a first horizontal portion that is substantially horizontal below the developing rotator, has a second horizontal portion that is substantially horizontal below the conveying member, and has a second horizontal portion that is below the toner stirring member. Having a concave portion continuous with the first and second horizontal portions,
The image forming apparatus according to claim 2, wherein: The concave portion has a bottom portion having a smaller radius than the trajectory of the tip of the flexible sheet due to the rotation of the toner stirring member.
The image forming apparatus according to claim 3, wherein: Biasing means for biasing the developing container toward the image carrier to bring the developing rotator into contact with the image carrier; Urging the developing container on a straight line connecting the center of the rotating body,
The image forming apparatus according to claim 1, wherein: An image forming apparatus main body to which the developing container is mounted, wherein the image forming apparatus main body holds the developing rotating body when the urging member urges the developing container toward the image carrier; First and second guide portions for guiding along a line connecting the center of the body and the center of the developing rotator near both ends in the longitudinal direction of the developing rotator;
The image forming apparatus according to claim 5, wherein: Having a magnet roller inside the developing rotator,
The first guide portion guides a rolling bearing that rotatably supports the shaft of the developing rotator, and the second guide portion guides a support member that non-rotatably supports the shaft of the magnet roller. ,
The image forming apparatus according to claim 6, wherein:

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