JP4835781B2 - Process unit - Google Patents

Description

  The present invention relates to a process unit including a drum frame on which a photosensitive drum is supported and a developing frame on which a developing roller is supported.

An example of a process unit that is detachably attached to an image forming apparatus such as a printer is disclosed in Patent Document 1, for example.
The process unit disclosed in Patent Document 1 is configured by mounting a developing cartridge on which a developing roller is rotatably supported on a photosensitive cartridge on which a photosensitive drum is rotatably supported, and has one end in the longitudinal direction of the developing cartridge. A coupling joint (development coupling) provided on the image forming apparatus transmits a rotational force input from the image forming apparatus side to the developing roller to rotate the developing roller. The developing cartridge is pressed toward the photosensitive drum by a pressing mechanism so that the outer peripheral surface of the developing roller is uniformly in contact with the outer peripheral surface of the photosensitive drum.

JP 2007-127995 A

  However, when rotational force is input to the coupling joint to drive the developing roller to rotate, rotational torque about the coupling joint as a rotation center acts on the developing cartridge. As long as the rotational torque is small, the image formation is not affected. However, when the rotational torque of the developing roller increases due to the increase in printing speed, the rotational torque acting on the developing cartridge also increases. Since the developing cartridge is not fixed to the photosensitive drum, the developing cartridge vibrates due to the rotational driving force input from the coupling joint. As a result, the pressing force between the developing roller and the photosensitive drum is not stable around one end that receives the driving input, and excessive pressing force causes fogging (dirt on a portion that should not be printed) or the width direction of the paper. Density unevenness at the edges may adversely affect image quality.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to stabilize the pressing force between the photosensitive drum and the developing roller so that a good image can be formed even when the rotational torque generated in the developing cartridge increases.

  The present invention that solves the above-described problems is a photosensitive drum, a drum frame that supports the photosensitive drum, a developing roller that contacts the photosensitive drum, a developing roller that supports the developing roller, and is swingably supported by the drum frame. A developing unit that is provided on one side of the developing roller in the direction of the rotation axis so that an external drive input unit can be engaged and disengaged in the direction of the rotation axis. In addition, the drum frame can be swung by a coupling joint that transmits the input rotational force to the developing roller and a support portion provided coaxially with the coupling joint on the other side in the rotational axis direction. The rotation center of the developing roller when viewed from the direction of the rotation axis is the rotation center of the photosensitive drum and the rotation center of the photosensitive drum. A structure that is positioned upstream of the line connecting the rotation center of the coupling joint in the rotation direction of the coupling joint and presses the developing roller against the photosensitive drum by the rotational force input to the coupling joint; It is characterized by that.

  According to such a configuration, when a rotational force is input to the coupling joint, a rotational moment that rotates the developing frame around the rotational axis of the coupling joint acts, and this rotational moment causes the developing roller to move to the photosensitive drum. Acts as a pressing force.

According to the present invention, even when the rotational torque of the developing roller is increased, the developing roller is stably pressed against the photosensitive drum, so that good image formation is possible. Since this rotational torque is input from the coupling joint, the force that separates the gears, which is a problem when using gears, does not work, and the rotational force around the rotational center of the coupling joint. Can only work.
Further, the rotation axis of the developing frame can exert only the rotational force around the rotation center of the coupling joint. That is, since the rotation axis of the developing frame is supported by the drum frame coaxially with the rotation axis of the coupling joint, the developing frame does not vibrate due to the rotational driving force input from the coupling joint. Further, since the developing frame can rotate coaxially with the coupling joint, the rotational moment is dispersed in the longitudinal direction of the developing roller and presses the photosensitive drum. As a result, the pressing force to the photosensitive drum at the time of driving input is stabilized.

<Overall configuration of laser printer>
Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the drawings to be referred to, FIG. 1 is a side sectional view of a main part of a laser printer according to an embodiment of the present invention.
As shown in FIG. 1, the laser printer 1 includes a feeder unit 4 for feeding a sheet 3 into a main body casing 2, an image forming unit 5 for forming an image on the fed sheet 3, and the like. ing.

  A front cover 2A that can be opened and closed is provided on the front side of the main casing 2 (in the following description, the right in FIG. 1 is the front and the left is the rear), and the opening that is formed when the front cover 2A is opened. Thus, a process cartridge 30 described later is detachable.

<Configuration of feeder section>
The feeder unit 4 includes a paper feed tray 11 that is detachably attached to the main casing 2 and a paper supply mechanism 15 that conveys the paper 3 from the paper feed tray 11 to the image forming unit 5. The paper supply mechanism 15 has a known paper feed roller, separation roller, separation pad, etc. (reference numerals omitted), separates the paper 3 in the paper feed tray 11 one by one, and conveys it to the upper image forming unit 5. .

<Configuration of image forming unit>
The image forming unit 5 includes a scanner unit 20, a process cartridge 30, a fixing unit 40, and the like.

<Configuration of scanner unit>
The scanner unit 20 is provided at an upper portion in the main body casing 2 and includes a laser light emitting unit (not shown), a polygon mirror 21 that is driven to rotate, lenses 22 and 23, reflecting mirrors 24 and 25, and the like. A laser beam based on the image data emitted from the laser emission unit is irradiated on the surface of the photosensitive drum 32 of the process cartridge 30 by high-speed scanning through a path indicated by a chain line.

<Configuration of process cartridge>
The process cartridge 30 is disposed below the scanner unit 20 and is configured to be detachably attached to the main body casing 2. The process cartridge 30 includes a photosensitive cartridge 30A that supports a photosensitive drum 32, and a developer cartridge 30B that contains toner as a developer therein.

  The photoreceptor cartridge 30A mainly includes a drum frame 31 constituting an outer frame, a photosensitive drum 32 provided in the drum frame 31, a scorotron charger 33, and a transfer roller 34.

  The developer cartridge 30 </ b> B includes a developing roller 36, a supply roller 38, a layer thickness regulating blade 39, and an agitator 70 in a developer case 35 as an example of a developing frame that forms a developer containing chamber 61 that contains the developer. Yes. Among these, the developing roller 36, the supply roller 38, and the agitator 70 are rotatably supported by the developer case 35. The toner T in the developer case 35 is supplied to the developing roller 36 by the rotation of the supply roller 38 in the arrow direction (counterclockwise direction). At this time, the toner T is positively supplied between the supply roller 38 and the developing roller 36. Frictional charge. The toner T supplied onto the developing roller 36 enters between the layer thickness regulating blade 39 for regulating the layer thickness and the developing roller 36 as the developing roller 36 rotates in the arrow direction (counterclockwise direction). Then, it is carried on the developing roller 36 as a thin layer having a constant thickness.

  The photosensitive drum 32 is supported by the drum frame 31 coupled to the developer cartridge 30B so as to be rotatable in the arrow direction (clockwise). The photosensitive drum 32 has a drum body grounded and a surface portion formed of a positively chargeable photosensitive layer.

  The scorotron charger 33 is disposed above the photosensitive drum 32 so as to face the photosensitive drum 32 with a predetermined interval therebetween. The scorotron charger 33 is a positively charged scorotron charger that generates corona discharge from a charging wire such as tungsten, and is configured to uniformly charge the surface of the photosensitive drum 32 to a positive polarity. ing.

  The transfer roller 34 is disposed below the photosensitive drum 32 so as to face and contact the photosensitive drum 32, and is supported by the drum frame 31 so as to be rotatable in an arrow direction (counterclockwise direction). The transfer roller 34 is configured by covering a metal roller shaft with a conductive rubber material. A transfer bias is applied to the transfer roller 34 by constant current control during transfer.

  The surface of the photosensitive drum 32 is uniformly positively charged by the scorotron charger 33 and then exposed by high-speed scanning of the laser beam from the scanner unit 20. Thereby, the potential of the exposed part is lowered, and an electrostatic latent image based on the image data is formed. Here, the “electrostatic latent image” refers to an exposed portion of the surface of the photosensitive drum 32 that is uniformly positively charged and exposed to a laser beam to have its potential lowered. Next, when the developing roller 36 rotates, the toner T carried on the developing roller 36 is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 32 when it comes into contact with the photosensitive drum 32. Is done. The toner T is selectively carried on the surface of the photosensitive drum 32 to be visualized, whereby a toner image is formed by reversal development.

  Thereafter, the photosensitive drum 32 and the transfer roller 34 are rotationally driven so as to sandwich and convey the sheet 3 between them, and the sheet 3 is conveyed between the photosensitive drum 32 and the transfer roller 34, so that the photosensitive drum 32 and the transfer roller 34 are photosensitive. The toner image carried on the surface of the drum 32 is transferred onto the paper 3.

<Configuration of fixing unit>
The fixing unit 40 is disposed on the downstream side of the process cartridge 30, and includes a heating roller 41 and a pressure roller 42 that is disposed opposite to the heating roller 41 and sandwiches the sheet 3 between the heating roller 41. Yes. In the fixing unit 40 configured as described above, the toner T transferred onto the sheet 3 is thermally fixed while the sheet 3 passes between the heating roller 41 and the pressure roller 42, and then The paper 3 is conveyed to the paper discharge path 44. The paper 3 sent to the paper discharge path 44 is discharged onto a paper discharge tray 46 by a paper discharge roller 45.

<Details of process cartridge structure>
Next, details of the process cartridge 30 will be described. In the drawings to be referred to, FIG. 2 is an exploded perspective view of the process cartridge 30, and FIG. 3 is a side view of the process cartridge 30. 4 is a cross-sectional view of the developer cartridge as viewed from above, and FIG. 5 is a side view showing a state where a gear cover provided on the side surface of the developer cartridge is removed.

  As shown in FIG. 2, the process cartridge 30 is attached to the left side surface of the drum frame 31, a photosensitive cartridge 30 </ b> A that rotatably supports the photosensitive drum 32, a developer cartridge 30 </ b> B that rotatably supports the developing roller 36. It comprises a support plate 80 as an example of the support member and a support plate 90 attached to the right side surface. In this specification, the right and left are directions shown in FIG.

The support plate 80 is fixed to the left side plate 31 </ b> A of the drum frame 31 by screws 85. The support plate 80 is inserted into a drum positioning hole 81 for positioning through the rotation shaft 321 of the photosensitive drum 32 and a coupling joint 301 of the developer cartridge 30B described later, so that the coupling joint 301 rotates the photosensitive drum 32. And a joint positioning hole 82 for positioning at a constant distance from the shaft 321.
Both the drum positioning hole 81 and the joint positioning hole 82 are formed with the support plate 80 in a cylindrical shape.

The support plate 90 is fixed to the right side plate 31 </ b> B of the drum frame 31 with screws 95. The support plate 90 is formed with a columnar protrusion 91 protruding inward in the left-right direction, and a through hole 92 below the protrusion 91. The protrusion 91 is inserted into a support hole 302 of the developer case 35 to be described later, and supports the developer cartridge 30B to the drum frame 31 so as to be swingable. When both the support plate 80 and the support plate 90 are fixed to the drum frame 31, the center of the joint positioning hole 82 is positioned on the axis of the protrusion 91.
The through hole 92 is fitted into a protrusion 31 </ b> C protruding outward in the left-right direction on the right side plate 31 </ b> B of the drum frame 31, and functions to position the support plate 90 relative to the drum frame 31.

  In the developer cartridge 30B, a coupling joint 301 to which a rotational force is input from an external drive input unit is provided on one side in the axial direction of the developing roller 36, and a protrusion 91 of the support plate 90 is inserted on the other side. A support hole 302 as an example of the support portion is provided coaxially with the coupling joint 301.

  In the developer cartridge 30B, the protrusion 91 is inserted into the support hole 302, the coupling joint 301 is inserted into the joint positioning hole 82 of the support plate 80, and the support plates 80 and 90 are fixed to the photoreceptor cartridge 30A. The developer cartridge 30 </ b> B can swing around the rotation center of the coupling joint 301.

As shown in FIG. 3, the end surface of the coupling joint 301 is exposed in the joint positioning hole 82 of the support plate 80 on the left side surface of the process cartridge 30, and the rotation axis of the coupling joint 301 is inside the main body casing 2. A drive input section (not shown) provided so as to be able to advance and retreat in the direction can be engaged and disengaged.
A protective ring 305 formed on a part of the gear cover 300 is fitted on the coupling joint 301 to protect the sliding surface of the coupling joint 301.
In addition, a snap ring 83 is attached to the rotating shaft 321 of the photosensitive drum 32 protruding from the drum positioning hole 81 to define the position of the photosensitive drum 32 in the axial direction.

As shown in FIG. 4, the coupling joint 301 passes through the gear cover 300 on the side surface of the developer case 35, and the transmission gear 304 is provided at the inner end in the left-right direction.
The transmission gear 304 meshes with the developing roller gear 362 attached to the rotation shaft 361 of the developing roller 36, and the rotational force input to the coupling joint 301 is transmitted to the developing roller 36 via the transmitting gear 304 and the developing roller gear 362. And the developing roller 36 is driven to rotate.

Further, as shown in FIG. 5, the transmission gear 304 meshes with the supply roller gear 382 attached to the rotation shaft 381 of the supply roller 38 and also idles with the agitator gear 702 attached to the rotation shaft 701 of the agitator 70. It also meshes with the gear 703, and the rotational force input to the coupling joint 301 is transmitted to the supply roller 38 and the agitator 70 via these gears 382, 703, 702, and the supply roller 38 and the agitator 70 are driven to rotate. .
The photosensitive drum 32 is engaged with an external driving force input gear in a gear 322 provided at the left end of the photosensitive drum 32 shown in FIG. Yes.

As shown in FIG. 4, the developing roller 36 has one end side (left side) of the rotating shaft 361 inserted into a bearing 354 provided on the developer case 35 and the other end side (right side) provided on the developer case 35. The cylindrical bearing 351 is inserted and supported by the developer case 35.
Here, the right bearing 351 is formed as a part of the bearing member 350. The bearing member 350 is formed by integrating a member constituting the support hole 302 that receives the protrusion 91 of the support plate 90 and the bearing 351, and is fixed to the developer case 35 by a screw 353 so as to be integrally fixed. ing.

  At both ends in the axial direction of the developing roller 36, there are parts made of a cylindrical resin coaxial with the developing roller 36, contacting the surface of the photosensitive drum 32, and the surface of the photosensitive drum 32 and the center of the developing roller 36. An abutting roller 363 that restricts the upper limit of the pressing force of the developing roller 36 against the photosensitive drum 32 by restricting the distance from the shaft is provided. The outer diameter of the abutting roller 363 is slightly smaller than the outer diameter of the developing roller 36. When the developing roller 36 is pressed against the photosensitive drum 32 and crushed by a predetermined amount, the abutting roller 363 contacts the photosensitive drum 32, The developing roller 36 is prevented from being crushed by a predetermined amount or more. This is because the pressing force of the developing roller 36 is made constant by keeping the distance between the rotation shaft of the developing roller 36 and the surface of the photosensitive drum 32 constant.

In the photosensitive drum 32, one end side (left side) of the rotating shaft 321 is inserted into the drum positioning hole 81 of the support plate 80 provided in the drum frame 31, and the other end side (right side) is inserted into the right plate 31B itself of the drum frame 31. It is inserted into the provided support hole 311 and supported by the drum frame 31.
The supply roller 38 that supplies the toner T to the developing roller 36 is supported by the developer case 35 at both ends of the rotating shaft 381.

  In the process cartridge 30 of this embodiment, the rotation shaft 361 of the developing roller 36, the rotation shaft 321 of the photosensitive drum 32, and the rotation shaft 381 of the supply roller 38 are positioned in parallel to each other.

As shown in FIG. 6, when the developer cartridge 30 </ b> B is viewed from the rotation axis direction of the developing roller 36, the rotation center X of the developing roller 36 is the rotation center Y of the photosensitive drum 32 and the rotation center Z of the coupling joint 301. The positional relationship among the photosensitive drum 32, the developing roller 36, and the coupling joint 301 is defined so as to be positioned upstream of the line L connecting the two in the rotation direction of the coupling joint 301 (lower side in the figure). .
In the present embodiment, the positional relationship between the rotation center Y of the photosensitive drum 32 and the rotation center Z of the coupling joint 301 is defined by the support plate 80 and the support plate 90 provided in the photoreceptor cartridge 30A. The positional relationship among the photosensitive drum 32, the developing roller 36, and the coupling joint 301 is satisfied.

The operational effects of the process cartridge 30 configured as described above will be described.
As shown in FIG. 5, when the coupling joint 301 is rotated in the direction indicated by the arrow (clockwise) by the rotational force input from the drive input unit, along with the rotation of the coupling joint 301, The developing roller 36 is rotated in the direction of the arrow (counterclockwise) in the drawing.
At this time, in this embodiment, the non-magnetic one-component toner T is used as the developer, and the toner T is frictionally charged by pressing the layer thickness regulating blade 39 against the developing roller 36. Due to the friction between the layer 36 and the layer thickness regulating blade 39, a resistance is applied to rotate the developing roller 36 and the supply roller 38. Since this resistance is intended to integrate the developing roller 36 and the supply roller 38, when the coupling joint 301 is rotated, the entire developer cartridge 30 </ b> B is rotated to rotate around the rotation center of the coupling joint 301. As shown in FIG. 6, this rotational force gives a rotational moment that turns the developing roller 36 around the rotation center Z of the coupling joint 301.

In response to this rotational moment, the rotation center X of the developing roller 36 rotates around the rotation center Z of the coupling joint 301 and is coupled with the rotation center Y of the photosensitive drum 32 on the locus indicated by the symbol F in the drawing. It moves toward a line L connecting the rotation center Z of the joint 301.
At this time, the developing roller 36 rotates around the rotation center Z while pressing the photosensitive drum 32 positioned on the downstream side in the rotation direction, and the position where the developing roller 36 is in contact with the photosensitive drum 32 is indicated by reference numeral f2 in the drawing. A force in the tangential direction and a pressing force toward the center of the photosensitive drum 32 indicated by reference numeral f1 are applied.

Here, since the abutting rollers 363 made of resin are provided at both ends in the axial direction of the developing roller 36, the photosensitive drum 32 and the abutting roller 363 come into contact after the developing roller 36 is crushed by a predetermined amount. Thus, the developing roller 36 is prevented from being further crushed. Therefore, the force with which the developing roller 36 is pressed against the photosensitive drum 32 is constant over the entire axial direction.
As a result, a toner image having a uniform density is formed on the entire surface of the photosensitive drum 32 in the axial direction, thereby preventing the occurrence of fog and the like due to uneven pressing force and enabling good image formation.

According to the above, the following effects can be obtained in the present embodiment.
When the developing roller 36 is viewed from the direction of the rotation axis 361, the rotation center X of the developing roller 36 is more than the line L connecting the rotation center Y of the photosensitive drum 32 and the rotation center Z of the coupling joint 301. It is located upstream in the rotation direction. The developing roller 36 is rotated around the rotation center Z of the coupling joint 301 by the rotational force input to the coupling joint 301 and is pressed against the photosensitive drum 32. The developing roller 36 can be brought into uniform contact with the photosensitive drum 32 in the longitudinal direction by the rotational force applied. In the present embodiment in which the rotation of the developing roller 36 receives resistance by the layer thickness regulating blade 39, such an effect is particularly remarkable when the rotational speed of the developing roller 36 is increased. That is, the present invention is particularly effective when the non-magnetic one-component toner T is used.

  As a result, it is possible to prevent the occurrence of fogging due to uneven pressing force and the occurrence of wavy density unevenness appearing on the edge of the paper 3, thereby enabling good image formation. Further, image formation can be performed while positively using the rotational moment around the rotation center Z of the coupling joint 301 generated by the rotational force input to the coupling joint 301.

  Since the driving force input to press the developing roller 36 against the photosensitive drum 32 is input from the coupling joint 301, only a moment for rotating the developer case 35 around the axis of the coupling joint 301 is applied. Can be given. That is, if a driving force is input to the gear instead of the coupling joint 301, the gear is given a force that escapes from another gear that gives the driving force. The rotational moment is not stable. However, in this embodiment, since the coupling joint 301 in which the member for inputting the driving force is engaged and disengaged in the axial direction is employed, only the rotational moment around the coupling joint 301 can be obtained.

  Since the developer case 35 is swingably supported by the drum frame 31 by the coupling joint 301 and the support hole 302 that are coaxially disposed, the developer case 35 is rotated by the rotational driving force input from the coupling joint 301. The developer case 35 does not vibrate. Further, since the developer case 35 can rotate coaxially with the coupling joint 301, the rotational moment is dispersed in the longitudinal direction of the developing roller 36 and presses the photosensitive drum. As a result, the pressing force to the photosensitive drum at the time of driving input is stabilized. Further, since the rotation axis of the coupling joint 301 and the swing axis of the developer case 35 with respect to the drum frame 31 coincide with each other, a force for bending the developer frame 35 due to the input of the driving force from the coupling joint 301 is obtained. Does not work.

Further, the coupling joint 301 is inserted into the drum positioning hole 81 for positioning the rotating shaft 321 of the photosensitive drum 32 and the coupling joint 301 so that the coupling joint 301 is positioned at a certain distance from the rotating shaft 321 of the photosensitive drum 32. It was set as the structure supported through the support plate 80 in which the joint positioning hole 82 to be formed was formed.
As a result, the positional relationship between the rotation center Y of the photosensitive drum 32 and the rotation center Z of the coupling joint 301 is accurately determined, and the rotation shaft 361 of the developing roller 36 to which the rotational force is transmitted from the coupling joint 301 and the photosensitive drum. Since the positional relationship between the drum 32 and the rotating shaft 321 is also accurately defined, the developing roller 36 can be disposed at a position where it can be reliably brought into contact with the photosensitive drum 32.

Moreover, the coupling joint 301, at a joint positioning holes 82, and a configuration that is supported by a protective ring 305.
Thereby, wear of the coupling joint 301 sliding in the joint positioning hole 82 can be prevented.

Further, abutting rollers 363 for adjusting the pressing force of the photosensitive drum 32 by the developing roller 36 are provided at both ends in the axial direction of the developing roller 36.
Thereby, the axial distance between the developing roller 36 and the photosensitive drum 32 can be made constant, and the pressing force of the developing roller 36 to the photosensitive drum 32 can be made constant.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the embodiment, the support plate 80 and the support plate 90 are provided on the left side and the right side of the drum frame 31, respectively, and the developer case 35 is supported by the support plates 80 and 90. The developer case 35 may be supported by the left side plate 31A or the right side plate 31B of the drum frame 31 on one or both of the right side and the right side.

  The developer cartridge 30B is supported by inserting a protrusion 91 of a support plate 90 fixed to the photosensitive cartridge 30A into a support hole 302 provided on the other side in the axial direction of the developing roller 36. However, a protrusion may be provided instead of the support hole 302, and the protrusion may be inserted into a support hole provided in the photoreceptor cartridge 30A to be supported.

Further, in the above-described embodiment, the developer cartridge 30B is attached to the photoreceptor cartridge 30A by the coupling joint 301 provided on one side and the support hole 302 provided coaxially with the coupling joint 301 on the other side. Although it was supported so that it could swing,
As shown in FIG. 7, the coupling joint 301 and the support hole 302 may be connected by a connecting member. In the process cartridge 30 ′ shown in FIG. 7, an auger 306 engaged with the inside of the coupling joint 301 is provided, and the auger 306 passes through the right side wall of the developer cartridge 30B. That is, in the form of FIG. 7, the bearing member 350 is integrally provided with the bearing 352 of the auger 306 in addition to the bearing 351 of the developing roller 36, and is fixed to the developer case 35.

  In the case where there is no connection member as in the above embodiment, the rotational force input from the coupling joint 301 acts to twist the developer case 35. Since the force is transmitted from the left side to the right side via the connecting member, the twist of the developer case 35 is suppressed. In this embodiment, since the connecting member is the auger 306 disposed in the developer accommodating chamber 61, the toner T in the developer accommodating chamber 61 can be agitated by the rotation of the coupling joint 301. In this embodiment, the connecting member does not necessarily pass through the developer case 35 and may be exposed outside the developer case 35.

  In the embodiment, the coupling joint 301 is supported by the support plate 80 via the protection ring 305. However, the protection ring 305 is not essential, and the coupling joint 301 is directly connected to the drum positioning hole 81 of the support plate 80. It may be supported by.

In the embodiment, the plate-like support plate 80 is illustrated as an example of the support member, but the support member is fixed to the drum frame 31 from the axial direction of the coupling joint 301 and the photosensitive drum 32. The coupling joint 301 and the photosensitive drum 32 can be engaged, and the distance between the axis of the photosensitive drum 32 and the coupling joint 301 is defined. be able to. For example, as shown in FIGS. 8A and 8B, not limited to the plate shape, a portion for forming the support hole 191 of the coupling joint, and a portion for forming the support hole 192 for supporting the photosensitive drum 32. It is also possible to adopt a form like a support rod 190 in which the two are connected by a rod-shaped member 193.

It is principal part side sectional drawing of the laser printer which concerns on embodiment of this invention. It is a disassembled perspective view of a process cartridge. It is a side view of a process cartridge. FIG. 3 is a cross-sectional view of the developer cartridge as viewed from above. FIG. 6 is a side view showing a state where a gear cover provided on the side surface of the developer cartridge is removed. It is a figure explaining arrangement | positioning of a developing roller. It is sectional drawing which looked at the process cartridge which concerns on a modification from the top. (A) The front view which shows the other example of a supporting member, and the XX sectional drawing of (b) (a).

30 Process Cartridge 30A Photosensitive Cartridge 30B Developer Cartridge 31 Drum Frame 32 Photosensitive Drum 35 Developer Case (Developing Frame)
36 Development roller 38 Supply roller 80 Support plate 81 Drum positioning hole 82 Joint positioning hole 90 Support plate 91 Protrusion 301 Coupling joint 302 Support hole 305 Protective ring 306 Auger 363 Abutting roller

Claims (14)

A photosensitive drum;
A drum frame supporting the photosensitive drum;
A developing roller in contact with the photosensitive drum;
A developing frame that supports the developing roller and is swingably supported by the drum frame;
The developing frame is provided on one side of the developing roller in the rotational axis direction, and an external drive input unit can be engaged and disengaged in the rotational axis direction, and the input rotational force is transmitted to the developing roller. A coupling joint having a gear part;
A support portion provided on the other side of the developing frame in the rotation axis direction and provided coaxially with the rotation axis of the coupling joint;
An agitator for stirring the developer in the development frame;
A gear that rotates with the agitator;
An idle gear for transmitting driving force from the gear portion of the coupling joint to the gear;
With
The developing frame is
The drum joint is swingably supported by the coupling joint and the support portion,
The rotation center of the developing roller when viewed from the rotation axis direction is
The process unit is located upstream of the line connecting the rotation center of the photosensitive drum and the rotation center of the coupling joint in the rotation direction of the coupling joint.   The said coupling joint is supported by the 1st support member provided in the said drum frame, The said developing frame is supported by the said drum frame so that rocking | fluctuation is possible. Process unit.   The process unit according to claim 2, wherein the first support member is fixed to the drum frame with a screw.   The first support member is inserted with a drum positioning hole for positioning the rotating shaft of the photosensitive drum and the coupling joint, and the joint positioning for positioning the coupling joint at a certain distance from the rotating shaft of the photosensitive drum. The process unit according to claim 2 or 3, wherein a hole is formed. 5. The process unit according to claim 4, wherein the coupling joint is supported by the joint positioning hole via a protective member that covers an outer peripheral surface of the coupling joint and protects the coupling joint.
The protective member is
The process unit according to claim 5, wherein the process unit is formed integrally with a gear cover that protects the gear. The process unit according to claim 6, wherein the gear cover is fixed to the developing frame with a screw.
The support part is
The developing frame is swingably supported by the drum frame by being supported by a second support member having an engaging portion that engages with the supporting portion. The process unit according to claim 7. The second support member is
The process unit according to claim 8, further comprising a positioning hole for positioning the second support member in the drum frame.   2. An abutting roller that is provided coaxially with the developing roller at both ends in the axial direction of the developing roller and that defines a pressing force between the developing roller and the photosensitive drum is provided. The process unit according to claim 9.   The process unit according to any one of claims 1 to 10, wherein the coupling joint and the support portion are connected to each other by a connection member.   The process unit according to claim 11, wherein the connection member is an auger provided in the developing frame.   The support portion is a support hole provided in the development frame, and the development frame is supported by the drum frame by inserting a protrusion provided in the drum frame into the support hole. The process unit according to any one of claims 1 to 12.   The process unit according to claim 13, wherein a bearing of the developing roller and a member constituting the support hole are integrally formed.