Developing device

Abstract

To improve the workability in replacing a developing device 10 mounted in an image forming apparatus body.SOLUTION: A fixation part 13 is fixed to an image forming apparatus body when a developing device 10 is mounted in the image forming apparatus body, with a first positioning hole 131 being positioned by a first positioning shaft of the image forming apparatus body. A developing device body 14 has a developing roller 12, and is movably connected to the fixation part 13 with an engagement part 15. An urging part 19 is provided between the fixation part 13 and the developing device body 14 and generates, at the fixation part 13, a second moment in a direction opposite to a first moment generated at the fixation part 13 due to backlash of the engagement part 15. The first positioning hole 131 is formed along a predetermined direction. In a state where the first moment and the second moment are balanced with each other, an angle formed by the predetermined direction and a rotation axis α of the developing roller 12 is 3° or less.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to a developing device that develops an electrostatic latent image formed on an image carrier with a developer, and to an image forming apparatus such as a copier, printer, facsimile, or a multifunction machine having a plurality of these functions. [Background technology]

[0002] In an image forming apparatus, a configuration is known in which a developing device is detachable from the image forming apparatus body for easy maintenance and replacement. The developing device is movable to a position separated from a developer carrier such as a developing roller with respect to a photosensitive drum so as not to come into contact with an image carrier such as a photosensitive drum in the image forming apparatus body when the developing device is attached to or detached from the image forming apparatus body.

[0003] For example, the developing device in Patent Document 1 is capable of swinging about an axis to approach and separate from the photosensitive unit when mounted in the normal mounting position of the device main body. Furthermore, the developing device has a bridging member attached to the front frame of the developing device that bridges the opening of the front frame of the device main body from above to below, and the front end of the axis is rotatably supported by a bearing provided on the bridging member.

[0004] Furthermore, Patent Document 1 describes that a configuration may be adopted in which the developing device combined with the bridging member is inserted into the device body, and the bridging member is attached to the front frame of the device body. In such a configuration, the bridging member is fixed to the front frame of the device body in a state in which it is cantilevered via a shaft on the front side of the developing device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-58627 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Document 1, in the case where the bridging member is supported by a cantilever on the developing device, there is a risk that the bridging member will tilt due to play at the engagement portion between the bridging member and the developing device. When the bridging member is attached to the frame of the device body, for example, it is positioned by engagement between a protrusion provided on one side of the bridging member and the frame and a hole provided on the other side. In this case, if the bridging member is inserted into the device body in a state inclined with respect to the developing device, the protrusion will tilt with respect to the hole, and when the protrusion engages with the hole, there is a risk that it will be difficult or impossible to insert the developing device to the correct position in the device body. As a result, the workability of replacing the developing device will be reduced.

[0007] SUMMARY OF THE DISCLOSURE An object of the present invention is to provide a configuration that can improve the ease of replacing a developing device in an image forming apparatus main body. [Means for solving the problem]

[0008] The developing device of the present invention is a developing device that is detachable from an image forming apparatus main body, and has a positioned portion that is positioned to a positioning portion of the image forming apparatus main body when the developing device is attached to the image forming apparatus main body, and a fixed portion that is fixed to the image forming apparatus main body with the positioned portion positioned to the positioning portion, a developing device main body that is rotatable about a rotation axis and has a developing roller for developing an electrostatic latent image on an image carrier provided in the image forming apparatus main body with a developer, and is movably connected to the fixed portion by an engagement portion, and and a biasing portion that is provided between the image forming apparatus main body and the image forming device body and biases the fixed portion so as to generate a second moment in the fixed portion in a direction opposite to a first moment that is generated in the fixed portion due to the backlash of the engaging portion and the relationship between the position of the engaging portion and the center of gravity position of the fixed portion when the positioned portion is not positioned in the positioning portion, wherein the positioned portion is a protrusion or hole portion formed along a predetermined direction, and when the first moment and the second moment are balanced, the angle between the predetermined direction and the rotation axis of the developing roller is 3° or less.

[0009] The developing device of the present invention is a developing device detachable from an image forming apparatus main body, and includes a positioned portion that is positioned to a positioning portion of the image forming apparatus main body when the developing device is attached to the image forming apparatus main body, and a fixed portion that is fixed to the image forming apparatus main body with the positioned portion positioned to the positioning portion, the fixed portion having a supply port through which developer is supplied from the image forming apparatus main body, and a developing device main body having a developer carrier for developing an electrostatic latent image on an image carrier provided in the image forming apparatus main body with developer, the developing device main body being movably connected to the fixed portion by an engagement portion, and a developing device body having a front end connected to the fixed portion and a developer carrier for developing an electrostatic latent image on an image carrier provided in the image forming apparatus main body with developer, the developing device main body being movably connected to the fixed portion by an engagement portion, The present invention is characterized in that it comprises an elastically deformable developer transport path arranged between the fixed part and the developing device main body, the developer transport path connecting the supply port provided in the fixed part and a connection port provided in the developing device main body to supply developer supplied from the supply port to the inside of the developing device main body, and an elastic member arranged between the fixed part and the developing device main body, which biases the fixed part so as to generate a moment in the opposite direction to the moment generated in the fixed part due to the backlash of the engagement part and the relationship between the position of the engagement part and the center of gravity position of the fixed part when the positioned part is not positioned in the positioning part.

[0010] The image forming apparatus of the present invention further comprises an image forming apparatus main body having an image carrier and a positioning portion, and a developing device detachable from the image forming apparatus main body, the developing device having a positioned portion that is positioned in the positioning portion when the developing device is attached to the image forming apparatus main body, a fixed portion that is fixed to the image forming apparatus main body with the positioned portion positioned in the positioning portion, a developing device main body having a developer carrier for developing an electrostatic latent image on the image carrier with a developer, the developing device main body being movably connected to the fixed portion by an engagement portion, and a developing device provided between the fixed portion and the developing device main body, The present invention is characterized in that the device is equipped with a biasing portion that biases the fixed portion so as to generate a second moment in the opposite direction to a first moment that is generated in the fixed portion due to the backlash of the engaging portion when the positioned portion is not positioned in the positioning portion and the relationship between the position of the engaging portion and the center of gravity position of the fixed portion, one of the positioning portion and the positioned portion is a hole portion formed along a first direction, and the other is a protrusion formed along a second direction and capable of engaging with the hole portion, and when the first moment and the second moment are balanced, the angle between the first direction and the second direction is 3° or less.

[0011] and a developing device detachable from the image forming device body, the image forming device body having a supply port for supplying a developer to the developing device, a shutter for opening and closing the supply port, and a shutter biasing portion for biasing the shutter in a direction for closing the shutter. The developing device has a positioned portion which is positioned by the positioning portion when the developing device is attached to the image forming device body, and a fixed portion which is fixed to the image forming device body with the positioned portion positioned at the positioning portion; a developing device body having a developer carrier for developing an electrostatic latent image on the image carrier with a developer, the developing device body being movably connected to the fixed portion by an engagement portion; and a biasing portion which is provided between the fixed portion and the developing device body and biases the fixed portion, the fixed portion being in contact with the shutter when the developing device is attached to the image forming device body and biasing the shutter in a direction for closing the shutter. The developing device has a fixed portion side abutment portion that opens the shutter against the biasing force of the shutter biasing portion, and a supply port that is connected to the supply port when the developing device is attached to the image forming apparatus main body, and the biasing portion biases the fixed portion so as to generate a fourth moment in a direction opposite to a third moment that is obtained by adding a moment that acts on the fixed portion by a reaction force of the shutter biasing portion when the developing device is attached to the image forming apparatus main body to a moment that is generated on the fixed portion due to the backlash of the engagement portion and the relationship between the position of the engagement portion and the center of gravity position of the fixed portion when the positioned portion is not positioned in the positioning portion, and one of the positioning portion and the positioned portion is a hole portion formed along a first direction, and the other is a protrusion formed along a second direction and capable of engaging with the hole portion, and when the third moment and the fourth moment are balanced, the angle between the first direction and the second direction is 3° or less. Effect of the Invention

[0012] According to the present invention, the workability of replacing the developing device in the main body of the image forming apparatus can be improved. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of a photoconductor unit according to the first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of a photoconductor unit according to the first embodiment. [Figure 4] FIG. 2 is a perspective view of a developing device according to the first embodiment. [Diagram 5] FIG. 2 is a cross-sectional view of a developing device according to the first embodiment. [Figure 6] FIG. 2A is a perspective view showing a pressure-released state of the developing device according to the first embodiment, and FIG. [Figure 7] FIG. 4 is a cross-sectional view showing a pressure-released state of the developing device according to the first embodiment. [Figure 8] FIG. 2 is a perspective view showing a pressurized state of the developing device according to the first embodiment. [Figure 9] FIG. 4 is a cross-sectional view showing a pressurized state of the developing device according to the first embodiment. [Figure 10] 5 is a cross-sectional view of a front portion and a frame of the developing device, illustrating an ideal state of a positioning attitude of a fixed portion of the developing device relative to an image forming apparatus. [Figure 11] 11 is a cross-sectional view of a front portion of the developing device and a frame, showing a state in which a fixing portion of the developing device is inclined with respect to the image forming apparatus. FIG. [Figure 12] 5A and 5B are diagrams for explaining the relationship between forces and moments around a fixed portion of the developing device. [Figure 13] 6A and 6B are diagrams for explaining the relationship between forces and moments around the fixed portion of the developing device when the fixed portion is inclined. [Figure 14] FIG. 2 is a cross-sectional view showing a front portion of the developing device according to the first embodiment. [Figure 15] 11 is a table showing the results of investigating the relationship between the angle between the positioning shaft and the positioning hole and the mountability of the developing device. [Figure 16] FIG. 11 is a cross-sectional view showing a front portion of a developing device according to a second embodiment. [Figure 17]13 is a cross-sectional view of the front side of the developing device for illustrating a state in which a reaction force of a shutter biasing portion acts on a fixed portion when the developing device is inserted into the main body of the image forming apparatus; FIG. [Figure 18] FIG. 11 is a cross-sectional view showing a front portion of a developing device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <First embodiment> The first embodiment will be described with reference to Figures 1 to 15. First, the schematic configuration of an image forming apparatus according to the present embodiment will be described with reference to Figure 1.

[0015] [Image forming equipment] The image forming apparatus 100 of this embodiment is an electrophotographic tandem-type full-color printer equipped with four image forming units PY, PM, PC, and PK, each of which has a photosensitive drum 201 as an image carrier. The image forming apparatus 100 forms a toner image on a recording material in response to an image signal from a document reading device 102 connected to the image forming apparatus main body 101 or a host device such as a personal computer connected to the image forming apparatus main body 101 so as to be able to communicate with the image forming apparatus main body 101. Examples of the recording material include sheet materials such as paper, plastic film, and cloth. The image forming units PY, PM, PC, and PK form yellow, magenta, cyan, and black toner images, respectively.

[0016] The four image forming units PY, PM, PC, and PK included in the image forming apparatus 100 have substantially the same configuration, except for the different developing colors. Therefore, the image forming unit PY will be described as a representative, and descriptions of the other image forming units will be omitted.

[0017] In the image forming unit PY, a cylindrical photosensitive member, i.e., a photosensitive drum 201, is disposed as an image carrier. The photosensitive drum 201 is rotated by a driving force transmitted from a driving unit (not shown) provided in the image forming apparatus main body 101. In the image forming unit PY, a charging roller 204 as a charging unit, a developing device 10, a primary transfer roller 31 as a transfer member, and a cleaning blade 206 as a cleaning member are disposed around the photosensitive drum 201. An exposure device (a laser scanner in this embodiment) 22 as an exposure unit is disposed below the photosensitive drum 201 in the figure.

[0018] In the image forming section PY, a cylindrical photosensitive member, i.e., a photosensitive drum 201, is disposed as an image carrier. The photosensitive drum 201 is rotated by a driving force transmitted from a driving section, such as a motor (not shown), provided in the image forming apparatus main body 101. Around the photosensitive drum 201, a charging roller 204 as a charging section, a developing device 10, a primary transfer roller 31 as a transfer member, and a cleaning blade 206 as a cleaning member are disposed. An exposure device (a laser scanner in this embodiment) 22 as an exposure section is disposed below the photosensitive drum 201 in the figure.

[0019] Toner is supplied to the developing device 10 from a toner bottle 21 serving as a toner storage container through a toner transport path (not shown). In addition, in the image forming section PY, a cleaning roller 205 serving as a charge cleaning member for cleaning the charge member is arranged in contact with the charge roller 204 (see FIG. 3). In this embodiment, the charge roller 204 is brought into contact with the surface of the photosensitive drum 201 with a predetermined pressing force by a biasing member such as a spring, and rotates in accordance with the rotation of the photosensitive drum 201. In addition, the cleaning roller 205 is brought into contact with the surface of the charge roller 204 with a predetermined pressing force by a biasing member such as a spring, and rotates in accordance with the rotation of the charge roller 204.

[0020] An intermediate transfer device 300 is disposed above each image forming unit in FIG. 1. The intermediate transfer device 300 is configured such that an endless intermediate transfer belt 30 serving as an intermediate transfer body is stretched around a plurality of rollers and moves (rotates). A primary transfer roller 31 is disposed at a position facing each photosensitive drum 201 on the inner peripheral surface side (back surface side) of the intermediate transfer belt 30. The primary transfer roller 31 is pressed against the photosensitive drum 201 via the intermediate transfer belt 30, forming a primary transfer portion where the intermediate transfer belt 30 and the photosensitive drum 201 are in contact with each other. The primary transfer roller 31 rotates in accordance with the rotation of the intermediate transfer belt 30.

[0021] Further, a secondary transfer roller 32, which is a roller-shaped secondary transfer member, is disposed at a position facing the secondary transfer opposing roller 33 on the outer circumferential surface side (front surface side) of the intermediate transfer belt 30. The secondary transfer roller 32 is pressed against the secondary transfer opposing roller 33 via the intermediate transfer belt 30, forming a secondary transfer section where the intermediate transfer belt 30 and the secondary transfer roller 32 are in contact with each other. Further, a belt cleaning device 35, which serves as an intermediate transfer body cleaning section, is disposed at a position facing the tension roller 34 on the outer circumferential surface side of the intermediate transfer belt 30. The intermediate transfer belt 30 is formed endlessly from a dielectric resin such as polyimide.

[0022] A fixing device 60 that fixes the toner image to the recording material P is disposed downstream of the secondary transfer portion in the recording material transport direction. The fixing device 60 has, for example, a fixing roller as a fixing rotator heated by a heat source such as a heater, and a pressure roller as a pressure rotator that forms a fixing nip portion between the fixing roller and the fixing roller. The toner image on the recording material transported to the fixing nip portion is heated and pressurized, thereby fixing the toner image to the recording material.

[0023] A cassette 40 containing recording material P is disposed at the bottom of the image forming apparatus 100. The recording material P fed from the cassette 40 is conveyed by conveying rollers 41 toward the registration rollers 50. Then, the leading edge of the recording material P hits the registration rollers 50, which are in a stopped state, and a loop is formed, thereby correcting the skew of the recording material P. Thereafter, the registration rollers 50 start to rotate in synchronization with the toner image on the intermediate transfer belt 30, and the recording material P is conveyed to the secondary transfer section.

[0024] A process of forming, for example, a four-color full-color image by the image forming apparatus 100 configured as described above will be described. First, when an image forming operation starts, the surface of the rotating photosensitive drum 201 is uniformly charged to a predetermined potential of a predetermined polarity by the charging roller 204. In this embodiment, a voltage is applied to the charging roller 204 from a high-voltage power source (not shown), causing discharge on the surface of the photosensitive drum 201, thereby charging the surface of the photosensitive drum 201.

[0025] Next, the photosensitive drum 201 is scanned and exposed by a laser beam corresponding to an image signal generated by the exposure device 22. As a result, an electrostatic latent image corresponding to the image signal is formed on the photosensitive drum 201. The electrostatic latent image on the photosensitive drum 201 (on the image carrier) is visualized by toner contained in the developing device 10 as a developer, and becomes a visible image. In this embodiment, the normal charging polarity of the toner is negative. The developing device 10 has a developing roller 12 as a developer carrier that carries the toner and transports it to a portion (developing position) facing the photosensitive drum 201. The developing roller 12 is driven to rotate. During development, a predetermined developing voltage is applied to the developing roller 12 from a high-voltage power source as a developing power source (not shown).

[0026] The toner image formed on the photosensitive drum 201 is primarily transferred to the intermediate transfer belt 30 at a primary transfer section formed between the photosensitive drum 201 and a primary transfer roller 31 arranged with the intermediate transfer belt 30 sandwiched therebetween. At this time, a primary transfer bias, which is a voltage of the opposite polarity (positive polarity in this embodiment) to the charge polarity of the toner during development, is applied to the primary transfer roller 31 from a high-voltage power source (not shown). Toner remaining on the surface of the photosensitive drum 1 after the primary transfer (transfer residual toner) is removed by a cleaning blade 206, collected in a collected toner transport path, and discharged outside the photosensitive unit 20 by a toner transport screw 207 (see FIG. 3).

[0027] Such an operation is performed in sequence in each image forming section for yellow, magenta, cyan, and black, and the four color toner images are superimposed on the intermediate transfer belt 30. After that, the recording material P stored in the cassette 40 is conveyed to the secondary transfer section in accordance with the timing of the formation of the toner images. Then, in the secondary transfer section, the four color toner images on the intermediate transfer belt 30 are secondarily transferred all at once onto the recording material P by the action of the secondary transfer opposing roller 33. When the recording material P passes through the secondary transfer section, a secondary transfer voltage, which is a voltage of the opposite polarity to the charge polarity of the toner at the time of development, is applied to the secondary transfer roller 32 from a high-voltage power source (not shown). Toner that was not transferred in the secondary transfer section and remains on the intermediate transfer belt 30 is removed by a belt cleaning device 35.

[0028] Next, the recording material P is conveyed to the fixing device 6, where it is heated and pressurized as it passes through the fixing nip. The toner on the recording material P is then melted and mixed, and fixed as a full-color image onto the recording material P. Thereafter, the recording material P is discharged onto the discharge tray 80 by the discharge rollers 70. This completes a series of image forming processes.

[0029] In addition, the image forming apparatus 100 of this embodiment is also capable of forming a monochrome or multi-color image, such as a monochrome black image, by using image forming units for a desired monochrome color or for some of the four colors.

[0030] [Photoconductor unit] 2 and 3, the configuration of the photoconductor unit 20 will be described. The photoconductor unit 20 of this embodiment is configured such that a photoconductor drum 201 as a photoconductor, a charging roller 204 as a charging member, a cleaning roller 205 as a charging cleaning member, and a cleaning blade 206 as a cleaning member are integrally held by a drum frame 202 as a frame. The photoconductor unit 20 is detachable from the image forming apparatus main body 101 by sliding it from the image forming apparatus main body 101 along the longitudinal direction (the direction of the rotation axis of the photoconductor drum 201), and can be replaced for maintenance or the like.

[0031] A photosensitive drum 201 is supported on the drum frame 202 so as to be rotatable about a rotation axis via a bearing (not shown). The photosensitive drum 201 is provided with a coupling 203 for receiving a driving force from a motor (not shown) provided in the image forming apparatus main body 101 as a driving source and rotating the photosensitive drum 201 when the photosensitive drum 201 is attached to the image forming apparatus main body 101.

[0032] The charging roller 204 is rotatably supported by a charging roller bearing (not shown), and is pressed against the photosensitive drum 201 by a pressure spring (not shown). The cleaning roller 205 is rotatably supported by a cleaning roller bearing (not shown), and is pressed against the charging roller 204 by a pressure spring (not shown). In addition, a cleaning blade 206 is fixed to the drum frame 202 as a cleaning member for cleaning the surface of the photosensitive drum 201, and is provided so as to come into contact with the surface of the photosensitive drum 201 in a counter direction to the rotation direction of the photosensitive drum 201 during image formation.

[0033] A toner transport path is provided near the cleaning blade 206 to collect and transport the transfer residual toner removed from the surface of the photosensitive drum 201 by the cleaning blade 206. The toner transport path is provided with a toner transport screw 207 as a transport member for transporting the collected toner to the outside of the photosensitive unit 20. The toner transported to the outside of the photosensitive unit 20 by the toner transport screw 207 is collected in a collected toner container (not shown) provided in the image forming apparatus main body 101.

[0034] [Developing device] Next, the configuration of the developing device 10 will be described with reference to Figures 4 and 5. The developing device 10 is a developing device that uses a two-component developer containing non-magnetic toner and a magnetic carrier. The developing device 10 of this embodiment is configured to be detachable from the image forming device main body 101 by sliding it from the image forming device main body 101 along the longitudinal direction (the direction of the rotation axis of the developing roller 12), and can be replaced for maintenance or the like.

[0035] In this embodiment, the developing device 10 and the above-mentioned photoconductor unit 20 can be inserted and pulled out along the longitudinal direction relative to the image forming apparatus main body 101. The inserting direction of the developing device 10 and the photoconductor unit 20 is the direction from the front side to the rear side of the image forming apparatus 100 (from the front side to the rear side of the paper in FIG. 1). The front side of the image forming apparatus 100 is the side where an operator operates the image forming apparatus 100, for example, the side where an operation unit for operating the image forming apparatus 100, such as an operation panel, is located. Hereinafter, when the terms "front side" and "rear side" are simply used, they refer to the front side and the rear side of the image forming apparatus 100.

[0036] The developing device 10 is provided with a toner supply port 133 as a supply port, and when the developing device 10 is attached to the image forming apparatus main body 101, the toner supply port 133 is connected to a supply port of a toner transport path provided in the image forming apparatus main body 101. The toner transport path is connected to a toner bottle 21 that contains replenishment toner as a developer storage container. Therefore, replenishment toner is supplied to the toner supply port 133 from the toner bottle 21 via the toner transport path.

[0037] The developing device 10 also includes a developing container 11 that contains a developer, and a developing roller 12 as a developer carrier. The developing roller 12 is held rotatably relative to the developing container 11 about a rotation axis α, and is configured to develop an electrostatic latent image formed on the photosensitive drum 201 at a development position where the photosensitive drum 201 and the developing roller 12 face each other. Driving force is transmitted to the developing roller 12 from the rear side of the image forming apparatus main body 101 via a coupling 17.

[0038] In addition, in the developing device 10, there are disposed a developing blade 112 for regulating the toner coat amount on the surface of the developing roller 12 to a constant amount, and screw members 113 and 114 for stirring and conveying the toner in the toner storage section 111 in the developing container 11. In the developing device 10, the developer in the toner storage section 111 is stirred and conveyed by the screw members 113 and 114 to be carried on the surface of the developing roller 12, and the layer thickness (coat amount) of the developer carried on the developing roller 12 is regulated by the developing blade 112. Then, the developer whose layer thickness has been regulated is conveyed to a development position by the rotation of the developing roller 12, and is used to develop an electrostatic latent image on the photosensitive drum 201. The developer remaining on the developing roller 12 after development is collected in the toner storage section 111, and is stirred and conveyed again by the screw members 113 and 114.

[0039] After being inserted into the image forming apparatus main body 101, the developing device 10 is positioned relative to the photosensitive unit 20 by being pressed by a developing pressure mechanism 23 (described later) provided in the image forming apparatus main body 101, and the developing roller 12 and the photosensitive drum 201 are arranged close to each other with a predetermined gap between them.

[0040] [Development pressure mechanism] As described above, the developing device 10 can be replaced for maintenance or the like, but in the image forming state, the developing roller 12 and the photosensitive drum 201 are disposed in close proximity to each other. Therefore, if the developing device 10 is inserted or removed from the image forming apparatus main body 101 in this state, there is a possibility that the developing roller 12 or the photosensitive drum 201 may be scratched by friction. Therefore, when installing or removing the developing device 10 or the photosensitive unit 20, it is necessary to first separate the developing roller 12 and the photosensitive drum 201 by a sufficient distance so that they do not rub against each other.

[0041] For this reason, the developing device 10 of this embodiment has a fixed part 13 fixed to the image forming device main body 101, and a developing device main body 14 which is a movable part movable relative to the fixed part 13. The fixed part 13 is located upstream of the developing roller 12 in terms of the insertion direction of the developing device 10 into the image forming device main body 101. In other words, the fixed part 13 is a part which positions and fixes the front part of the developing device 10 with respect to the image forming device main body 101.

[0042] In this embodiment, as described later, after the fixing part 13 is positioned on a frame 90 (see FIG. 10, etc.) of the image forming apparatus main body 101, the fixing part 13 is fixed to the frame 90 by a fastening member such as a screw. As a result, the developing device 10 is fixed to the image forming apparatus main body 101 and prevented from coming off from the image forming apparatus main body 101. The prevention of the developing device 10 from coming off is not limited to this configuration. For example, after the developing device 10 is mounted on the image forming apparatus main body 101, as described later, when the pressure lever 233 is rotated to position the developing device main body 14 at the pressure position, a part of the pressure lever 233 or a member provided on the pressure shaft 231 may be engaged with the end face on the front side of the fixing part 13. In any case, it is sufficient that after the fixing part 13 is positioned on the frame 90, the fixing part 13 is fastened or engaged with a member on the image forming apparatus main body 101 side, so that the developing device 10 is fixed so as not to come off on the front side in the insertion direction.

[0043] In this embodiment, the direction of movement of the developing device main body 14 relative to the fixed portion 13 is the direction of rotation about an engagement portion 15, which will be described later. The developing device main body 14 has a developing roller 12. A developing and pressurizing mechanism 23 can move the developing device main body 14 between a first position (contact position) where the developing roller 12 is close to the photosensitive drum 201 and a second position (separated position) where the developing roller 12 is further away from the photosensitive drum 201 than the first position. At the contact position, a part of the developing device main body 14 contacts a part of the photosensitive unit 20, thereby determining the positional relationship between the developing roller 12 and the photosensitive drum 201.

[0044] The configuration and operation of such a developing and pressurizing mechanism 23 will be described with reference to Figs. 6(a) to 9. Figs. 6(a) and 7 are perspective and sectional views showing a developing and pressurizing release state, i.e., a state in which the developing device 10 is not pressed against the photosensitive unit 20 and the developing device main body 14 is located at a second position where the developing roller 12 is separated from the photosensitive drum 201. Figs. 8 and 9 are perspective and sectional views showing a developing and pressurizing state, i.e., a state in which the developing device 10 is pressed against the photosensitive unit 20 and the developing device main body 14 is located at a first position where the developing roller 12 is close to the photosensitive drum 201. Fig. 6(b) is an enlarged sectional view of a fixing portion 13 and an engagement portion 15 of the developing device main body 14, which will be described later.

[0045] The developing and pressurizing mechanism 23 includes a rod-shaped pressurizing shaft 231 arranged parallel to the longitudinal direction of the developing device 10, and a pressing portion 232 is arranged on the pressurizing shaft 231. In this embodiment, the pressing portions 232 are provided at two positions, one on the front side and one on the rear side of the pressurizing shaft 231, and each of them rotates together with the pressurizing shaft 231. A pressing lever 233 is engaged with the pressurizing shaft 231 on the front side of the image forming apparatus main body 101, and the pressurizing shaft 231 can be rotated by operating the pressing lever 233. In addition, the pressing portion 232 is biased by a biasing member such as a spring (not shown) so as to protrude in a direction away from the pressurizing shaft 231.

[0046] As shown in FIGS. 7 and 9, when the developing device 10 is attached to the image forming device main body 101, the developing device main body 14 is connected to the fixed part 13 by the engagement part 15 on the front side, and is connected to the image forming device main body 101 by the engagement part 115 on the rear side. The developing device main body 14 is rotatable about the rotation axis β (see FIG. 4) of the rotation shafts 15a, 115a of the engagement parts 15, 115. The rotation shafts 15a and 115a are arranged coaxially. In this embodiment, the developing device main body 14 is directly positioned with respect to the image forming device main body 101 at the rear side of the developing device 10. On the other hand, the developing device main body 14 is positioned with respect to the image forming device main body 101 via the fixing part 13 at the front side of the developing device 10.

[0047] The rear engagement portion 115 is an engagement portion between a rotation shaft 115a provided on the rear side of the image forming apparatus main body 101 and a hole 115b formed in an attachment portion 150 provided on the rear side of the developing device main body 14. That is, when the developing device 10 is inserted, the hole 115b provided on the rear side of the developing device main body 14 engages (specifically, fits) with the rotation shaft 115a provided on the rear side of the image forming apparatus main body 101 so as to protrude toward the front side. As a result, the rear side of the developing device main body 14 is positioned so as to be rotatable about the engagement portion 115 between the hole 115b and the rotation shaft 115a.

[0048] As shown in FIG. 6(b), the front engaging portion 15 is composed of a first hole 15b provided in the fixed portion 13, a second hole 15c provided in the developing device main body 14, and a rotating shaft 15a as a shaft portion that engages with the first hole 15b and the second hole 15c. The rotating shaft 15a is a bolt having a head 15a1 at its base end and a threaded portion 15a2 at its tip outer circumferential surface. An insert nut 15d is provided in the fixed portion 13, and the inner circumferential surface of the insert nut 15d constitutes the first hole 15b. That is, the inner circumferential surface of the first hole 15b is a female threaded portion. The inner circumferential surface of the second hole 15c is a cylindrical surface with no threaded portion formed thereon. Also, a female threaded portion may be formed directly on the inner circumferential surface of the first hole 15b.

[0049] When connecting the fixed part 13 and the developing device main body 14, the first hole part 15b of the fixed part 13 and the second hole part 15c formed in the mounting part 151 provided on the front side of the developing device main body 14 are arranged coaxially, and the rotating shaft 15a is inserted through the second hole part 15c. Then, the screw part 15a2 of the rotating shaft 15a is screwed and fixed into the first hole part 15b, so that the mounting part 151 is sandwiched between the fixed part 13 and the head part 15a1. As a result, the developing device main body 14 is connected to the fixed part 13 by the engagement part 15 so as to be rotatable about the rotating shaft 15a.

[0050] The rear engaging portion 115 may have a rotation shaft on the developing device main body 14 side and a hole on the image forming device main body 101 side. The front engaging portion 15 may have an inner peripheral surface of the second hole portion 15c as a female screw portion and a first hole portion 15b as a cylindrical surface without a screw portion, and the rotation shaft 15a may be inserted through the first hole portion 15b. In this case, the fixing portion 13 is sandwiched between the head portion 15a1 of the rotation shaft 15a and the mounting portion 151 of the developing device main body 14, so that the developing device main body 14 is connected to the fixing portion 13 so as to be rotatable about the rotation shaft 15a.

[0051] Also, the engagement portion 15 on the front side may be composed of a shaft portion provided on one of the fixed portion 13 and the developing device main body 14, and a hole portion provided on the other and engageable with the shaft portion. For example, a shaft portion is provided on the fixed portion 13, and a hole portion is provided on the developing device main body 14. Also, the tip of the shaft portion is made a threaded portion, and after the shaft portion is inserted into the hole portion, a nut is screwed onto this threaded portion, thereby connecting the fixed portion 13 and the developing device main body 14. Of course, the relationship between the shaft portion and the hole portion may be reversed. That is, the shaft portion may be provided on the developing device main body 14 side, and the hole portion may be provided on the fixed portion 13 side.

[0052] In this embodiment, the rotating shaft 115a and the hole 115b constituting the rear engaging portion 115, and the rotating shaft 15a and the second hole 15c constituting the front engaging portion 15 are engaged (specifically, fitted) with each other so that the developing device main body 14 can rotate about the engaging portions 15, 115. For this reason, rattle occurs between the fixed portion 13 and the engaging portion 15 of the developing device main body 14, as described later.

[0053] In this way, the developing device main body 14 of the developing device 10 can rotate around the rotation shafts 15a, 115a to be movable between the abutment position and the separated position relative to the photosensitive unit 20. When the developing device main body 14 is simply mounted in the mounting position relative to the image forming device main body 101, it is in a state in which it is tilted counterclockwise CCW in the figure around the rotation axis β of the rotation shafts 15a, 115a due to its own weight as shown in Fig. 7, and the developing roller 12 is separated from the photosensitive drum 201. In other words, the developing device main body 14 is in the separated position. When the developing roller 12 and the photosensitive drum 201 are in this separated state, the developing device 10 can be attached to and detached from the image forming device main body 101 without colliding with or coming into contact with each other.

[0054] When the pressure lever 233 is rotated clockwise (CW) with the developing device 10 attached to the image forming apparatus main body 101, the pressing portion 232 on the pressure shaft 231 comes into contact with the pressure force receiving portions 143, 116 as contact portions provided on the developing device main body 14, as shown in Figures 8 and 9. The pressure force receiving portions 143, 116 are formed on mounting portions 151, 150 on the rear and front sides of the developing device main body 14, respectively.

[0055] Then, the developing device main body 14 rotates clockwise CW around the rotation axis β of the rotation shafts 15a and 115a, and the developing roller 12 moves to a contact position (first position) close to the photosensitive drum 201. At this time, the pressing portion 232 is biased by a biasing member (not shown), so that the developing device main body 14 is biased in the clockwise CW direction. The position of the pressing portion 232 in this case is referred to as a third position.

[0056] When the developing device main body 14 is in contact with the photosensitive unit 20, the pressing lever 233 is rotated counterclockwise CCW to release the pressing portion 232 on the pressing shaft 231 from contacting the pressure receiving portions 143 and 116 as shown in FIGS. 6 and 7. Then, the developing device main body 14 tilts counterclockwise CCW, the contact between the developing roller 12 and the photosensitive drum 201 is released, and the developing roller 12 moves to the separated position (second position). The position of the pressing portion 232 in this case is called the fourth position. In this way, the pressing portion 232 is movable between the third position where the pressing portion 232 contacts the pressure receiving portions 143 and 116 and presses the developing device main body 14 at the contact position as shown in FIGS. 8 and 9, and the fourth position where the pressing portion 232 is separated from the pressure receiving portions 143 and 116 and can move the developing device main body 14 to the separated position as shown in FIGS. 6 and 7.

[0057] As described above, the developing device 10 is divided into the developing device main body 14 as a movable part that rotates around the rotation shafts 15a, 115a by the pressure force of the developing pressure mechanism 23, and the fixed part 13 that is fixed to the image forming device main body 101. Specifically, the position of the fixed part 13 is restricted by the image forming device main body 101, and is connected to the developing device main body 14 by an engagement part (first connecting part) 15 via the rotation shaft 15a.

[0058] Further, the toner supply port 133, through which the developer is supplied from the image forming apparatus main body 101 side, is provided in the fixed part 13. The toner supply port 133 and a connection port 142 (FIGS. 4 and 8) provided in the developing device main body 14 are connected by a developer transport path 16 formed of a bellows-shaped elastic member. The connection port 142 is connected to the toner storage section 111 inside the developing device main body 14. That is, the developer transport path 16 is disposed between the fixed part 13 and the developing device main body 14, and connects the toner supply port 133 and the connection port 142 to supply the developer supplied from the toner supply port 133 to the toner storage section 111 inside the developing device main body 14 through the connection port 142. The developer transport path 16 is elastically deformable, and is configured to be capable of communicating the toner supply port 133 with the connection port 142 when the developing device main body 14 is in either the abutting position (pressurized position) or the separating position (pressurized release position).

[0059] [Pinching when installing the developing unit] Next, the prying during installation of the developing device 10 will be described with reference to FIGS. 10 to 13. FIG. 10 is a diagram showing an ideal state of the developing device 10 immediately before it is positioned in the image forming device main body 101. The developing device 10 can be inserted into and removed from the image forming device main body 101 in the X direction shown in FIG. 10. The X direction is parallel to the longitudinal direction of the developing device 10, that is, the direction of the rotation axis α of the developing roller 12. The image forming device main body 101 is provided with a first positioning shaft 901 and a second positioning shaft 902 for positioning the developing device 10 with respect to the image forming device main body 101. The first positioning shaft 901 and the second positioning shaft 902 are formed on the frame 90 on the front side of the image forming device main body 101 so as to protrude toward the front side along the first direction. The first direction is parallel to the central axis 901A of the first positioning shaft 901 and is also parallel to the X direction, which is the insertion and removal direction of the developing device 10.

[0060] Meanwhile, the developing device 10 is provided with a first positioning hole 131 and a second positioning hole 132 that engage with a first positioning shaft 901 and a second positioning shaft 902 of the image forming apparatus main body 101. The first positioning hole 131 and the second positioning hole 132 are formed in the fixed portion 13 so as to penetrate along the second direction and the predetermined direction. The second direction and the predetermined direction are parallel to a central axis 131A of the first positioning hole 131.

[0061] Here, the first positioning hole 131 is a hole for positioning the developing device 10, and the second positioning hole 132 is an elongated hole that functions as a hole for preventing rotation of the developing device 10. The second positioning hole 132 is formed so that its length in the up-down direction is longer than that of the first positioning hole 131 when the developing device 10 is attached to the image forming apparatus main body 101.

[0062] Therefore, when the developing device 10 is attached, first, the first positioning shaft 901 enters the first positioning hole 131 to position the developing device 10. At this time, the second positioning shaft 902 also enters the second positioning hole 132. However, since the second positioning hole 132 is an elongated hole, positioning in the vertical direction is not performed, but rotation about the engagement portion between the first positioning hole 131 and the first positioning shaft 901 is restricted.

[0063] In this embodiment, the first positioning hole 131 corresponds to the positioned portion, and the first positioning shaft 901 that engages with the first positioning hole corresponds to the positioning portion. The relationship between the shaft and the hole may be reversed. That is, one of the positioning portion and the positioned portion may be a hole portion formed along the first direction, and the other may be a protrusion formed along the second direction that can engage with the hole portion. In short, the positioning portion and the positioned portion may have a shape that allows them to be positioned when the developing device 10 is inserted into the image forming apparatus main body 101. The relationship between the shaft and the hole may also be reversed for the second positioning shaft 902 and the second positioning hole 132.

[0064] In an ideal posture, the central axis 901A of the first positioning shaft 901 and the central axis 131A of the first positioning hole 131 are parallel, that is, the first direction and the second direction are parallel. In an ideal posture, the developing device 10 can be mounted to the image forming apparatus main body 101 without twisting at the engagement portion between the first positioning shaft 901 and the first positioning hole 131. However, as shown in this embodiment, in the developing device 10 which is divided into the fixed part 13 fixed to the image forming apparatus main body 101 and the developing device main body 14 movable relative to the fixed part 13, inclination occurs due to engagement play of the engagement part (first connection part) 15 which is the connection part between the fixed part 13 and the developing device main body 14, and as shown in FIG. 11, there is a risk that the central axis 901A of the first positioning shaft 901 and the central axis 131A of the first positioning hole 131 will be inclined by an angle θ.

[0065] In this case, in this embodiment, the central axis 131A of the first positioning hole 131 is also inclined by the angle θ with respect to the rotation axis α of the developing roller 12. That is, in this embodiment, the central axis 901A of the first positioning shaft 901 is parallel to the X direction which is the insertion / removal direction of the developing device 10, that is, the direction of the rotation axis α of the developing roller 12. Therefore, when the central axis 131A of the first positioning hole 131 is inclined by the angle θ with respect to the central axis 901A of the first positioning shaft 901, it is also inclined by the angle θ with respect to the rotation axis α of the developing roller 12.

[0066] FIG. 12 is a cross-sectional view of the vicinity of the engaging portion 15 in a state where the fixed portion 13 is not inclined with respect to the developing device main body 14, and FIG. 13 is a cross-sectional view of the vicinity of the engaging portion 15 in a state where the fixed portion 13 is inclined. The fixed portion 13 is rotatably connected to the mounting portion 151 in which the pressure receiving portion 143 is formed via the rotating shaft 15a at the engaging portion 15. The mounting portion 151 is configured to be rotatably supported on the shaft end on the front side of the developing roller 12 via the connecting portion (second connecting portion) 141. This allows the developing roller 12 to rotate while supporting the mounting portion 151 on the shaft end on the front side of the developing roller 12. When the mounting portion 151 is pressed by the pressing portion 232 as described above, it abuts against the developing container 11 of the developing device main body 14, and rotates the developing device main body 14 around the engaging portion 15 relative to the fixed portion 13.

[0067] As described above, the engaging portion 15 has a backlash. In the fixed portion 13 supported via the engaging portion 15, the weight F1 of the fixed portion 13 acts on the center of gravity G, and a rotational moment M10 is generated around the engaging portion 15. That is, in a state in which the first positioning hole 131 is not positioned on the first positioning shaft 901, the rotational moment M10 is generated as a first moment in the fixed portion 13 due to the backlash of the engaging portion 15 and the relationship between the position of the engaging portion 15 and the center of gravity G of the fixed portion 13.

[0068] A developer transport path 16 made of an elastic material is provided between the fixed part 13 and the developing container 11, which is a part of the developing device main body 14. Therefore, when the above-mentioned rotational moment M10 that tilts the fixed part 13 with respect to the developing device main body 14 occurs due to backlash of the engaging part 15, a rotational moment M20 in the opposite direction to the rotational moment M10 is generated around the engaging part 15 due to the elastic reaction force F2 of the developer transport path 16.

[0069] However, if the magnitude of rotation moment M20 is smaller than the magnitude of rotation moment M10, the fixed portion 13 will be inclined with respect to the developing device body 14. Furthermore, when the developing device 10 is inserted into the image forming device body 101, the developing device body 14 is inserted along an insertion / removal guide (not shown) of the image forming device body 101, so the posture of the developing device 10 during insertion into the image forming device body 101 will follow the posture of the developing device body 14. That is, the inclination between the fixed portion 13 and the developing device body 14 can be considered as the inclination between the fixed portion 13 and the image forming device body 101.

[0070] Therefore, as shown in FIG. 13, when the developing device 10 is mounted to the image forming device body 101 with the fixing portion 13 tilted relative to the developing device body 14, the central axis 901A of the first positioning shaft 901 provided in the image forming device body 101 and the central axis 131A of the first positioning hole 131 provided in the fixing portion 13 are tilted by an angle θ as shown in FIG. 11. If θ is large, the first positioning shaft 901 and the first positioning hole 131 cannot be smoothly engaged with each other, and it may become difficult or impossible to insert the developing device 10 to the correct position. As a result, the workability of replacing the developing device 10 is reduced. Therefore, in this embodiment, the following configuration is adopted.

[0071] [Forcer part that forces the fixed part] 14 is a cross-sectional view showing the vicinity of the engaging portion 15 of this embodiment. In this embodiment, a biasing portion 19 that biases the fixed portion 13 so as to generate a second moment in the opposite direction to the rotational moment M10 described above is provided between the fixed portion 13 and the developing device main body 14. The biasing portion 19 is composed of the developer transport path 16 and an elastic member 18. The elastic member 18 is provided between the fixed portion 13 and the developing device main body 14 at a position adjacent to the developer transport path 16, and biases the fixed portion 13 so as to generate a rotational moment M30, which is a moment in the opposite direction to the rotational moment M10, in the fixed portion 13.

[0072] That is, in this embodiment, in contrast to the above-mentioned configuration, an elastic member 18 is installed between the fixed part 13 and the developing device main body 14. The elastic body reaction force F3 of the elastic member 18 is set to generate a rotation moment M30 sufficient to eliminate the inclination θ of the fixed part 13. Specifically, the rotation moment M30 that balances the rotation moment M10 due to its own weight and the rotation moment M20 due to the developer transport path 16 is applied to the fixed part 13 by the elastic member 18, thereby correcting the inclination θ of the fixed part 13. Therefore, the moment obtained by adding the rotation moment M30 due to the elastic member 18 to the rotation moment M20 due to the developer transport path 16 corresponds to a second moment in the opposite direction to the rotation moment M10 as the first moment.

[0073] In this embodiment, when the first moment and the second moment are balanced, that is, when the rotational moments M10, M20, and M30 are balanced, the angle (acute angle) θ between the direction (first direction) parallel to the central axis 901A of the first positioning shaft 901 and the direction (second direction and specified direction) parallel to the central axis 131A of the first positioning hole 131 is set to 3° or less. In other words, when the rotational moments M10, M20, and M30 are balanced, the angle (acute angle) θ between the direction (specified direction) parallel to the central axis 131A of the first positioning hole 131 and the rotational axis α of the developing roller 12 is set to 3° or less.

[0074] Since the rotation moment M around the engaging portion 15 is determined by the product of the force F and the arm length L, when generating a rotation moment of the same magnitude, the force F can be made smaller as the position of the point of application of the force is farther from the center position of the rotation moment. The elastic body reaction force F3 of the elastic member 18 is a reaction force to the pressure force applied to the developing device main body 14 by the developing pressure mechanism 23. In addition, the elastic member 18 is disposed on the front side of the developing device 10. Therefore, if F3 is large, a difference occurs between the pressure forces of the developing device main body 14 and the photoconductor unit 20 on the front side and the back side, which may cause problems in image formation.

[0075] In this embodiment, the center position of the rotation moment is the engagement portion 15, and the arm length L is the distance between the engagement portion 15 and the center axis 901A of the first positioning shaft 901, which is the point of application of the force, in the axial direction. The elastic member 18 is disposed at a position farther away from the center of gravity G of the fixed portion 13 and the developer transport path 16 with respect to the engagement portion 15. That is, the elastic member 18 is disposed so that the distance L3 from the engagement portion 15 to the elastic member 18 in the axial direction of the center axis 901A is longer than the distance L1 from the engagement portion 15 to the center of gravity G of the fixed portion 13, and is longer than the distance L2 from the engagement portion 15 to the developer transport path 16. For this reason, the elastic member 18 is capable of generating a rotation moment M30 that corrects the inclination of the fixed portion 13 with a small force. The position of the engagement portion 15, which is the reference for the distances L1, L2, and L3, is the end position on the far side of the attachment portion 151 in the engagement portion 15.

[0076] In this manner, in this embodiment, the elastic member 18 is disposed between the fixed portion 13 and the developing device main body 14, thereby correcting the inclination of the fixed portion 13 caused by the backlash of the engagement portion 15. As a result, the postures of the first positioning hole 131 of the fixed portion 13 and the first positioning shaft 901 of the image forming device main body 101 are in the ideal state shown in Fig. 10 or close to the ideal state, and the developing device 10 can be mounted on the image forming device main body 101 without any twisting.

[0077] In this embodiment, by providing elastic member 18 in addition to developer transport path 16, the angle θ between the direction parallel to central axis 901A of first positioning shaft 901 and the direction parallel to central axis 131A of first positioning hole 131 is set to 3° or less when rotation moments M10, M20, and M30 are balanced. The results of an investigation into this angle θ and the wobble that occurs when developing device 10 is attached to image forming apparatus main body 101 will be described with reference to FIG.

[0078] As shown in FIG. 15, when the angle θ exceeds 3° in absolute value, the first positioning hole 131 of the developing device 10 and the first positioning shaft 901 of the image forming apparatus main body 101 cannot be engaged to the normal position, and even if the developing device 10 is pushed further in the insertion direction from the state where it cannot be engaged, it cannot be pushed to the normal position. If the angle θ is in the range of 1° to 3° in absolute value, the developing device 10 can be mounted to the normal position by the additional pushing operation, although the engagement portion between the first positioning hole 131 and the first positioning shaft 901 is twisted. If the angle θ is less than 1° in absolute value, the developing device 10 can be mounted to the image forming apparatus main body 101 without being twisted at the engagement portion between the first positioning hole 131 and the first positioning shaft 901. From the above, in this embodiment, the angle θ is set to 3° or less. As a result, the ease of replacing the developing device 10 with respect to the image forming apparatus main body 101 can be improved.

[0079] <Second embodiment> The second embodiment will be described with reference to Figures 16 and 17. In the above-mentioned first embodiment, the urging portion 19 generates in the fixed portion 13 a second moment in a direction opposite to a first moment generated in the fixed portion due to the backlash of the engagement portion 15 and the relationship between the position of the engagement portion 15 and the position of the center of gravity of the fixed portion 13. In contrast, in this embodiment, the urging force of the urging portion 19A is set in consideration of the reaction force of the shutter urging portion 105 on the image forming apparatus main body 101 side that acts on the fixed portion 13 when the developing device 10 is inserted.

[0080] First, the shutter configuration on the image forming apparatus main body 101 side will be described with reference to FIG. 16. The image forming apparatus main body 101 has a supply port 103 for supplying developer to the developing device 10, a shutter 104 such as a spring for opening and closing the supply port 103, and a shutter biasing portion 105 for biasing the shutter 104 in a closing direction. When the developing device 10 is inserted into the image forming apparatus main body 101, the shutter 104 moves against the biasing force of the shutter biasing portion 105 to open the supply port 103. A through hole 104a is formed in the shutter 104. The supply port 103 and a toner supply port 133 on the developing device 10 side communicate with each other through the through hole 104a, and the developer can be supplied to the toner supply port 133 through the supply port 103.

[0081] For this purpose, the fixed part 13 of the developing device 10 has a fixed part-side abutment part 134 and a toner supply port 133 as a supply port. When the developing device 10 is attached to the image forming apparatus main body 101, the fixed part-side abutment part 134 abuts against the shutter 104 to open the shutter 104 against the biasing force of the shutter biasing part 105. The toner supply port 133 is connected to the supply port 103 when the developing device 10 is attached to the image forming apparatus main body 101.

[0082] In this manner, in the case where the shutter 104 is configured to open in conjunction with the mounting operation of the developing device 10, the developing device 10 receives a reaction force from the shutter 104. In the developing device 10 of this embodiment, as described above, the toner supply port 133 connected to the supply port 103 is provided on the fixed part 13, and the fixed part side abutment part 134 that abuts against the shutter 104 to open it is also provided on the fixed part 13. Therefore, the fixed part 13 receives an external force F4 due to the reaction force of the shutter 104 when the developing device 10 is inserted. Then, as shown in FIG. 17, the fixed part 13 receives a rotational moment M40 around the engagement part 15.

[0083] Fig. 17 is a diagram showing a state in which an external force F4 due to a reaction force of the shutter biasing portion 105 acts on the fixed portion 13. In Fig. 17, the biasing force of the biasing portion 19 is not set taking into consideration the external force F4. Therefore, the fixed portion 13 may be tilted by a rotation moment M40 generated by the external force F4. The rotation moment M40 is the product of the external force F4 and the distance L4 from the engagement portion 15 to the fixed portion side abutment portion 134.

[0084] For this reason, in this embodiment, as shown in Fig. 16, the biasing portion 19A is disposed between the fixed portion 13 and the developing device main body 14. Here, the rotation moment M10 generated in the fixed portion due to the backlash of the engaging portion 15 and the relationship between the position of the engaging portion 15 and the center of gravity position G of the fixed portion 13 in a state where the first positioning hole 131 is not positioned on the first positioning shaft 901, plus the rotation moment M40 acting on the fixed portion 13 due to the reaction force of the shutter biasing portion 105 when the developing device 10 is mounted on the image forming device main body 101, is defined as a third moment. The biasing portion 19A biases the fixed portion 13 so as to generate a fourth moment in the fixed portion 13 in the opposite direction to the third moment.

[0085] The biasing portion 19A has the developer transport path 16A and the elastic member 18A, which are elastic members, as in the first embodiment. The biasing force of these members is adjusted to generate the fourth moment. For example, the developer transport path 16A is set to be the same as the developer transport path 16 in the first embodiment, and the elastic member 18A is set to generate a biasing force larger than that of the elastic member 18 in the first embodiment. That is, the moment obtained by adding the rotation moment M31 by the elastic member 18A to the rotation moment M20 by the developer transport path 16A corresponds to the fourth moment in the opposite direction to the third moment (rotation moment M10+M40). As in the first embodiment, when the third moment and the fourth moment are balanced, the angle (acute angle) θ between the direction parallel to the central axis 901A of the first positioning axis 901 (first direction) and the direction parallel to the central axis 131A of the first positioning hole 131 (second direction and specified direction) is set to be 3° or less.

[0086] In this embodiment, the elastic member 18A is disposed between the fixed portion 13 and the developing device main body 14 to correct the backlash of the engagement portion 15 and the inclination of the fixed portion 13 caused by the reaction force of the shutter biasing portion 105 when the developing device 10 is inserted. As a result, the posture of the first positioning hole 131 of the fixed portion 13 and the first positioning shaft 901 of the image forming device main body 101 is in the ideal state shown in FIG. 10 or close to the ideal state, and the developing device 10 can be attached to the image forming device main body 101 without any twisting. This improves the ease of replacing the developing device 10 with respect to the image forming device main body 101.

[0087] <Third embodiment> The third embodiment will be described with reference to Fig. 18. In the above-mentioned first and second embodiments, in order to suppress the inclination of the fixed portion 13 due to the backlash of the engagement portion 15, elastic members 18, 18A are provided in addition to the developer transport paths 16, 16A. In contrast, in this embodiment, the inclination of the fixed portion 13 due to the backlash of the engagement portion 15 is suppressed only by the developer transport path 16B. Since the other configurations and functions are the same as those of the above-mentioned second embodiment, the same reference numerals are used for the similar configurations, and the description and illustrations are omitted or simplified, and the following description will focus on the points that are different from the second embodiment.

[0088] 19 is a cross-sectional view showing the vicinity of the engaging portion 15 in this embodiment. In this embodiment, the biasing portion 19B, which is disposed between the fixed portion 13 and the developing device main body 14 and biases the fixed portion 13, is formed only by the developer transport path 16B. That is, unlike the second embodiment, the elastic member 18A is not provided, and the developer transport path 16B alone biases the fixed portion 13 so as to generate a fourth moment in the opposite direction to the third moment, which is the sum of the rotational moment M10 and the rotational moment M40, in the fixed portion 13.

[0089] Methods for changing the elastic reaction force F2 of the developer transport path 16B include changing the Young's modulus by changing the material of the developer transport path 16B, changing the material thickness, changing the free length, etc. Note that the configuration of the first embodiment may also be configured such that the fixed portion 13 is biased only by the developer transport path as in this embodiment. In this embodiment, it is possible to improve the ease of replacement of the developing device 10 without increasing the number of parts from the conventional configuration. [Explanation of symbols]

[0090] 10. Developing device 12 Developing roller (developer carrier) 13... Fixed part 14. Developing device body 15 Engagement part 15a Rotating shaft (shaft) 15b...1st hole 15c...Second hole 16, 16A, 16B Developer transport path 18, 18A Elastic member 19, 19A, 19B...Biasing section 100 Image forming apparatus 101... Image forming apparatus main body 103 Supply port 104...Shutter 105 Shutter biasing portion 116, 143: Pressure receiving part (contact part) 131: First positioning hole (positioned portion) 133 Toner supply port (supply port) 134...Fixed part side contact part 201: Photosensitive drum (image carrier) 232 Pressing section 901: First positioning axis (positioning portion)

Claims

1. A developing device that can be attached to an image forming apparatus, a main body portion having a developer container that contains a developer containing toner and a carrier, and a developer carrier that carries and transports the developer to a development position where an electrostatic image formed on an image carrier is developed; a fixing portion that is fixed to the image forming apparatus in a state in which the main body portion is positioned on the image forming apparatus and the fixing portion is positioned on the image forming apparatus in order to mount the developing device on the image forming apparatus; a connecting portion that connects the main body portion and the fixing portion; a toner supply port provided in the fixed portion and through which the toner is supplied from the image forming apparatus; a connection port provided in the main body portion and connected to the developing container to supply the toner supplied through the toner supply port to the developing container; a toner transport path provided between the main body and the fixed part, the toner being able to communicate between the toner supply port and the connection port; a biasing portion that biases the fixed portion so that a second moment in an opposite direction to a first moment that is generated in the fixed portion about the connecting portion as a rotation center is generated in the fixed portion about the connecting portion as a rotation center in a state where the main body portion is positioned in the image forming apparatus and the fixed portion is not positioned in the image forming apparatus; Equipped with When the developing device is pressed by a pressure unit of the image forming apparatus with the fixed unit fixed to the image forming apparatus, the main body unit rotates about the connecting unit as a rotation center so that the developer carrier moves from a separated position separated from the developing position to the developing position. A developing device characterized by:

2. The biasing portion is an elastic member provided between the main body portion and the fixed portion.

2. The developing device according to claim 1.

3. In a mounting direction in which the developing device is mounted to the image forming apparatus, the fixed portion is located upstream of the developer carrier in the mounting direction.

2. The developing device according to claim 1.

4. In a mounting direction in which the developing device is mounted to the image forming apparatus, a position at which the fixing portion is positioned in the image forming apparatus is upstream of a position at which the main body portion is positioned in the image forming apparatus.

2. The developing device according to claim 1.

5. The fixing portion is fixed to the image forming apparatus by a fastening member in a state in which the main body portion is positioned on the image forming apparatus and the fixing portion is positioned on the image forming apparatus.

2. The developing device according to claim 1.

6. With respect to the mounting direction of the developing device in the image forming apparatus, The distance from the connecting portion to the center of gravity of the fixed portion is L1, The distance from the connecting portion to the toner transport path is L2, When the distance from the connecting portion to the biasing portion is L3, L1<L2<L3 fulfill 2. The developing device according to claim 1.

7. With respect to the mounting direction of the developing device in the image forming apparatus, the toner transport path is located upstream of the connecting portion, The biasing portion is located upstream of the toner transport path.

2. The developing device according to claim 1.

8. The toner transport path is formed by a bellows-shaped elastic member.

2. The developing device according to claim 1.

9. the fixing portion includes a first hole portion, the main body portion includes a second hole portion, The connecting portion has a shaft portion that is engaged with the first hole portion and the second hole portion.

2. The developing device according to claim 1.

Images