JPH05297647A - Process cartridge and image forming device capable of loading the same - Google Patents

Abstract

PURPOSE:To obtain a process cartridge and image forming device capable of dealing with a reduction in the diameter of an image carrier, an increase in the length in the rotating direction, etc. CONSTITUTION:The image forming device is provided with a housing 3 which integrally supports an image carrying drum and a process means which acts on the image carrying drum, a bearing part which is positioned in the housing 3 and which, when the process cartridge is loaded in the device main body, engages with a positioning shaft as a rotating central shaft for the image carrying drum attached to the device main body and drive transmitting gear parts 2b, 14a and 15a which transmit a rotating drive force, which the image carrying drum has received, to the process means in the process cartridge, the bearing part and the drive transmitting gear parts 2b, 14a and 15a being provided at the end part of the image carrying drum so as to be positioned on the same cross-section parpendicular to the rotating central shaft for the image carrying drum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge attachable to and detachable from an image forming apparatus and an image forming apparatus to which the process cartridge can be attached.

[0002]

2. Description of the Related Art Conventionally, there is a copying machine or a printer to which an electrophotographic method is applied as a process cartridge and one that drives the cartridge. An example of these cartridges will be described with reference to FIGS. 9 and 10. FIG. 9 is a perspective view showing a coupling portion of the cartridge with the apparatus main body, and FIG. 10 is a sectional view for explaining the coupling of the apparatus main body with the cartridge. Although process means such as a developing device and a cleaning device are supported together with the photosensitive drum 4 in the cartridge housing 7A, detailed description thereof is omitted here.

In the figure, a cartridge main shaft 5A formed by deforming a part of the photosensitive drum 4A and a drive transmission gear 6A fitted to the main shaft 5A are exposed on the side surface of the cartridge housing which is connected to the apparatus main body. ing. This gear 6A
Is partially processed, and a drive pin receiving rib 6C for receiving the drive pin 3B on the apparatus main body side is provided. On the other hand, the photosensitive drum 4A is supported by the housing 7A in a state where the cartridge housing engaging portion 6B is pivotally supported by the housing 7A.

On the other hand, on the apparatus body side, a drum drive gear 3A is rotatably attached to a main bearing 2A fixed to a body side plate 1B. The gear 3A driven by a drive means (not shown) is provided with a drive pin 3B which is movable in the left-right direction and is held by a spring so as to always project in the cartridge direction in the figure. With the above configuration, if the cartridge is moved in the direction of the arrow to be completely attached to the apparatus main body, the cartridge main shaft 5A engages with the main bearing 2A of the apparatus main body,
The cartridge is positioned. When the drum drive gear 3A rotates in this state, the rotating drive pin 3B engages with the drive pin receiving rib and pushes the drum 4A in the rotating direction, and as a result, the photosensitive drum 4A rotates.

[0005]

With the above construction, although the effect of reducing the size of the cartridge is produced, when the diameter of the photosensitive drum is reduced or the length in the rotational axis direction is longer than the diameter, Since the support position of the drum 4A and the position where the driving force is transmitted to this drum are deviated in the rotation axis direction, a biased force is applied, and the drum 4A vibrates or smooth rotation is impossible. May be.

In view of the above problems, the present invention is capable of sufficiently positioning the image bearing member, such as the photosensitive drum, to reduce the diameter of the photosensitive drum, increase the length in the rotational direction, and reduce the thickness of the drum. The present invention provides a process cartridge having a drive transmission mechanism and an image forming apparatus to which the process cartridge can be attached. At the same time, as shown in the above figures, the cartridge main shaft 5 provided on the photosensitive drum 4 is abolished, and each function is concentrated within the width of the drum, so that the process cartridge also has an effect of sufficiently protecting the cartridge against impact. And an image forming apparatus to which the process cartridge can be mounted. In addition, as the diameter of the photosensitive drum is reduced, it is possible to use a flange made of an insulating member such as resin, thereby realizing a compact and lightweight cartridge.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a process cartridge detachable from the main body of an image forming apparatus, an image carrying drum and a process acting on the image carrying drum. A housing that integrally supports the means, and a positioning shaft that is located inside the housing and that serves as a rotation center shaft for the image bearing drum that is attached to the apparatus body when the process cartridge is loaded in the apparatus body. And a drive transmission gear portion for transmitting the rotational driving force received by the image bearing drum to the process means in the process cartridge. The bearing portion and the drive transmission gear portion are the image bearing drum. A process in which the bearing portion and the drive transmission gear portion are provided at the end portion of the image bearing drum so as to be located on the same cross section perpendicular to the rotation center axis direction of It is a cartridges.

Still another aspect of the present invention is an image forming apparatus using a process cartridge integrally supporting an image bearing drum and a process means acting on the image bearing drum, and integrally supporting the image bearing drum and the process means. When the process cartridge is mounted in the main body of the apparatus, the bearing portion that is fitted to the positioning shaft as the rotation center axis for the image-carrying drum, which is mounted on the main body of the apparatus, is received by the image-carrying drum. And a drive transmission gear portion for transmitting the rotational drive force to the process means in the process cartridge, and these are arranged so that they are located on the same cross section perpendicular to the rotation center axis direction of the image bearing drum. Guide means for detachably guiding the process cartridge provided at the end, and a position as a rotation center axis for the image bearing drum fitted in the bearing portion. And decided axis, an image forming apparatus, characterized in that it comprises drive means for imparting a rotational drive force to the image bearing drum, a.

[0009]

EXAMPLES Examples described below are image bearing drums such as photosensitive drums and insulating drums, and process means such as a charger, a developing unit, a transfer unit, and a cleaning unit used for forming an image on the drum. Is a process cartridge that is integrally configured with at least one of the above and is detachable from the apparatus main body. Further, it is an image forming apparatus such as an electrophotographic copying machine or a recording device to which such a process cartridge is applied. More specifically, the process cartridge described below is provided at the end of the image bearing drum, and when this cartridge is loaded into the apparatus body, it is fitted with the positioning shaft for the image bearing drum attached to the apparatus body. Bearing part to
Positioning for the drum having a driving force receiving means that is provided integrally and concentrically with the rotation center axis of the image bearing drum to receive the rotational driving force for rotationally driving the drum. The bearing portion and the driving force receiving means are arranged at a position where at least a part of them overlaps with each other in the radial direction from the rotation center of the drum.

Further, in the process cartridge using the insulating flange, the drum member made of metal, the insulating flange member at the end portion, and the conducting member fixed to the inner peripheral surface on the inner side of the flange member of the drum member are provided. An image bearing drum provided, and a bearing portion that is provided on the flange of the image bearing drum and that is fitted to a positioning shaft for the image bearing drum that is attached to the apparatus body when the cartridge is loaded in the apparatus body, Positioning for the drum having a driving force receiving means that is provided integrally and concentrically with the rotation center axis of the image bearing drum to receive the rotational driving force for rotationally driving the drum. The bearing portion and the driving force receiving means are arranged at a position where at least a part thereof overlaps in the radial direction from the rotation center of the drum, and the image bearing is carried in the loaded state. Ram conductive member is disposed in a position in contact with the positioning shaft.

The process cartridges and the image forming apparatus in which the cartridges are loaded will be described below.

1 and 2 are cross-sectional views for explaining the connection between a process cartridge and a main body device to which the present invention is applied. In the drawing, reference numeral 1 denotes a photosensitive drum, and a resin flange 2 having a gear portion 2b for driving the internal mechanism of the cartridge, a housing engaging portion 2c, and a receiving portion 2f for the drum drive shaft at the center is fitted and fixed to one end of the photosensitive drum. ing. Reference numeral 3 is a casing of the cartridge, and a part of the drum receiving portion 3b receives the casing engaging portion 2c of the flange to support the drum 1. The drum drive shaft 4 is a member for positioning the drum 1 by fitting with the drive bearing portion 2f, and is pivotally supported by the side plate 7 of the apparatus main body by the spring bearing member bearing 5 and the bearing 6.
It is rotationally driven by the chain sprocket 8. The drive transmission element 10 for transmitting the rotation of the drive shaft 4 to the drum is held by the fixing member 11 so as not to idle in the circumferential direction with respect to the drive shaft 4, and is movable in the axial direction of the drive shaft 4. The coil spring 12 constantly urges the drum side. Further, the drive transmission 10 has a protrusion 10a,
When the drive shaft 4 rotates, the protruding portion 10a becomes a resin flange 2.
The photosensitive drum 4 is rotated by engaging with the drive transmission receiving portion 2d.

There is a conducting plate 13 that is strongly contacted and fixed to the inner wall of the drum, and when the cartridge is loaded in the main body of the apparatus, the spring portion 13a contacts the drive shaft 4 to establish electrical connection with the main body of the apparatus. ..

In the above structure, when the cartridge is mounted on the main body, first, the tip of the drive shaft 4 which also functions as the positioning of the cartridge is fitted into the drive shaft receiving portion 2f of the resin flange 2, and the position of the cartridge and the photosensitive drum 1 with respect to the main body of the apparatus. Is decided. If you push the cartridge further in,
The projecting portion 10 a of the drive transmission element 10 is the receiving portion 2 of the flange 2.
The drive shaft 4 and the drum are completely coupled by meshing with d.
When the positions of the projecting portion 10a and the receiving portion 2d do not match,
Although the tip of the protrusion 10a is pushed by the surface 2e and the transmitter is pushed leftward in the drawing, the drive shaft 4 further rotates and the protrusion 10a is pushed.
If the position of the receiving portion 2d and the position of the receiving portion 2d match, the transmission element 10 moves to the right in the figure by the coil spring 12, so that the protrusion 10a and the receiving portion 2d mesh with each other and rotate with the photosensitive drum grounded ( (Fig. 2).

FIG. 3 is a perspective view with a partial cross section showing a state where the cartridge is engaged with the apparatus main body side, and FIG. 4 is a perspective view with a partial cross sectional view showing the positioning and drive shaft 4 side of the direct resin flange 2 which is engaged. is there. FIG. 5 shows the conductive plate 13.
2 is a perspective view showing a mounting state of the photosensitive drum 1 on the photosensitive drum 1, in which the protrusion 13b is mounted on the inner peripheral surface of the drum.

The gear portion 2b of the process cartridge is, as shown in FIG. 6, a developing device 14 integrally supported in the cartridge.
14a for transmitting the driving force for rotating the developing sleeve of
And a gear 15a for transmitting a driving force for rotating the screw for forcibly conveying the toner of the cleaning device 15 which is also integrally supported.

When the rotational force of the flange 2 is further transmitted to the other means by the gear portion 2b in this manner, the force of the flange 2 eccentric to the drum drive shaft 4 is increased due to the load of each transmitted gear. come.

However, as in the present embodiment, at least a part of the fitting portion 2f between the drive shaft 4 of the drum and the flange 2 is at least partially in a direction perpendicular to the position of the gear portion 2b and the direction of the rotation axis. Are positioned so that they overlap each other, that is, at least part of the fitting portion 2f between the drive shaft 4 of the drum and the flange 2 and at least part of the gear portion 2b are perpendicular to the direction of the rotation center axis of the drum. By being located on the same cross section, the deformation and eccentricity of the gear portion 2b can be satisfactorily suppressed even when a high load is applied to the gear portion.

On the other hand, in this embodiment, since the transmission from the apparatus main body to the process cartridge is performed within the width of the photosensitive drum 1, as shown in FIG. 7, the photosensitive drum exposed from the cartridge housing 3 is The rotation center axis of the photosensitive drum for positioning as in the prior art does not project, and the flange having a complicated shape for receiving the drive is not largely exposed. Therefore, the positioning member and the driving member, which are important structures in the connection with the device main body,
It will not be damaged or deformed by rough handling.

FIG. 8 is a sectional view of the main part of an electrophotographic copying machine to which a process cartridge using the embodiment of the present invention is applied.

An apparatus 19 shown in the figure is a copying apparatus using an electrophotographic method, and a photosensitive drum 1 having a photoconductive layer provided on a conductive drum substrate is rotatably supported in a direction of an arrow.
Around the drum 1, a corona charger 16, a short focus optical element array 17, a developing device 1 are arranged in accordance with the rotation direction of the drum.
4. A transfer corona discharger 18 and a cleaning device 15 are provided. In this device 16, the discharge device 16, the developing device 14, and the cleaning device 14 together with the photosensitive drum 1 are used.
Are integrally supported by the housing 3 to form a process cartridge. The casing 3 is guided and supported by a guide rail 20 fixed to the main body side, and is attached to and detached from the main body device. The developing device 14 has a conventionally known hopper 14a for accommodating a developer in the upper part, and a developing roller 1 for supplying toner to the photosensitive drum 2 in the lower part.
4b. Specifically, a one-component developer using a magnetic toner or a two-component developer using a toner and a magnetic carrier can be used as the developer. As the developing roller 14b, it is possible to use a rotating magnetic roller having a magnetic pole on the surface thereof, or a magnetic roller having an internal magnetic roller and a non-magnetic sleeve provided along the peripheral surface thereof. As the cleaning device, a cleaning device using a blade plate or a cleaning device using a fur brush can be applied.

In the above copying apparatus, the corona discharger 1
6, the surface of the photosensitive drum 1 is uniformly charged with a predetermined polarity, and then the original on the reciprocating original table 21 on the upper part of the apparatus main body is illuminated by the lamp 22, and the reflected light is exposed on the drum 1 through the element array 17. To form a latent image. The formed latent image is developed by the developing device 14, and the developed image is transferred by the transfer corona discharger 18. The transfer material is supplied to the transfer material supply cassette 23 by an operator's manual operation, and the transfer roller 2
4 and the timing roller 25, and is conveyed to the transfer portion. The transfer material that has completed the transfer is sent to the fixing device 27 via the moving path 26 to be fixed, and is further sent out onto the paper discharge tray 30 via the discharge roller 29.

(Other Embodiment 1) In the embodiment described above, the photosensitive drum 1 is driven by transmitting the rotation of the positioning / driving shaft to the inside of the drum.
The positioning shaft provided in the apparatus body does not necessarily have to rotate.

FIG. 11 is a sectional view showing an engagement state between the process cartridge and the main assembly of the apparatus. The engagement portion 2f of the resin flange 2 of the photosensitive drum 1 is fitted with the cartridge positioning shaft 31 fixed to the side plate 7 of the main assembly of the apparatus. To meet. In this state, the drum drive gear 32 on the apparatus main body side meshes with the gear portion 2b of the flange 2. The flange 2 is rotated by the rotation of the drum drive gear 32, and as a result, the photosensitive drum 1 is rotated. Of course, the gear portion 2b of this flange 2
Further, as shown in FIG. 6, a gear for driving the process means in the cartridge may be meshed.

FIG. 12 is a perspective view showing a state where the flange 2 and the drum drive gear 32 are meshed with each other. Gear 3 above
The gear 2 is supported by the gear support side plate 34 together with the other gear 33. The support side plate 34 is axially supported by the swing center shaft 35, and is interlocked with the attachment / detachment of the cartridge, and has a position where it is engaged and a position where it is separated.

Also in the above embodiment, the fitting portion 2f in which the cartridge positioning shaft 31 fits with the flange 2 is the drum gear portion 2b to which the driving force is transmitted, or the transmitted driving force of the process means in the cartridge. The drum gear portion 2b, which is transmitted to the drive gear, overlaps with the drum gear portion 2b in a direction perpendicular to the central axis direction.

That is, also in the above embodiment, the cartridge positioning shaft 31 is fitted to the flange 2 by the fitting portion 2.
At least a part of f and at least a part of the drum gear part 2b to which the driving force is transmitted from the apparatus main body side, or at least a part of the drum gear part 2b to transmit the transmitted driving force to the gear of the process means in the cartridge. Are located on the same cross section perpendicular to the rotation center axis direction of the drum.

Therefore, even if an eccentric external force is applied to the photosensitive drum, the flange 2 can be held in the most stable state. Also in this embodiment, the photosensitive drum 1 has a small number of portions projecting from the casing 3 of the cartridge, and the casing 3 protects each portion for positioning and drive transmission.

In the above-described embodiment, the photosensitive drum 1 is composed of a metal drum member which is a conductive base body forming a cylindrical portion, and a resin flange which forms a flange (for example, a polycarbonate resin containing fluorine is used). .. In this way, by overlapping the positioning position and the drive transfer position for the photosensitive drum in the radial direction of the drum, that is,
By allowing them to exist on the same cross section that is perpendicular to the direction of the rotation center axis of the drum, a large biased force is not generated, so it is possible to widen the selection range of the flange material.

(Other Embodiment 2) In the above embodiment, the photosensitive drum 1 and the flange 2 are composed of separate members.
It is also effective for the photosensitive drum 39 in which the flange 36 is integrated by molding.

FIG. 13 shows a photosensitive drum 39 which employs a positioning mechanism corresponding to the structure of FIG. 1. The positioning / driving shaft 4 is fitted to the drum 39 via a bearing member 37. A gear 38 is fixed to the flange portion 36 by press fitting or adhesion.

In this embodiment, the structure of the present invention is adopted for the positioning of the drum and the relationship between this positioning position and the position of the gear 38.

Further, FIG. 14 employs a positioning mechanism corresponding to the configuration of FIG. 11, and achieves the effect of the present invention as in the case of FIG.

(Other Embodiment 3) In the above embodiments, the photosensitive drum is illustrated as the image bearing drum, but when a latent image is formed by modulated ions or multi-stylus electrodes, an insulating drum is used instead of the photosensitive drum. it can.

Next, regarding the structure of the process cartridge, the case where the casing integrally supports the image bearing drum, the corona discharger, the developing device and the cleaning device has been exemplified. For example, the image bearing drum and the discharger, or the image bearing drum. And a cleaning device, or an image bearing drum and a developing device, and other process means of the apparatus main body may be selectively integrated into a housing.

As an image forming apparatus to which the process cartridge having the above-mentioned photosensitive drum is applied, there is a printer using not the reflected light of the original but the modulated laser light in addition to the electrophotographic copying machine.

The above embodiment has the following effects.

1. Since the receiving portion on the cartridge side for the drum drive shaft and the cartridge positioning shaft on the apparatus main body is inside the cartridge housing, it is safe from being damaged or deformed from the outside.

2. Since the positioning portion, the drive receiving portion, or the delivery portion does not protrude from the cartridge housing, it is possible to realize the downsizing of the cartridge and the downsizing and weight reduction of the apparatus main body.

3. The cross-section where the position of the gear for transmitting the driving force to the inside of the cartridge or the position of the gear for directly receiving the driving force at least partially overlaps in the direction perpendicular to the central axis of the positioning shaft for positioning is pivotally supported. Therefore, that is, since the gears are located on the same cross section perpendicular to the rotation center axis direction of the drum together with the position of the gears, the eccentricity and deformation of the gears can be suppressed even when the load is high.

[0041]

As described in detail above, according to the present invention, the drive transmission gear portion for transmitting the rotational drive force received by the image bearing drum to the process means in the process cartridge, and the image mounted on the apparatus main body side. A positioning shaft as a rotation center shaft for the carrying drum and a bearing portion to be fitted therein are provided so as to be located on the same cross section perpendicular to the rotation center axis direction of the image carrying drum. With this configuration, according to the present invention, the bearing portion can reliably receive the urging force in the direction perpendicular to the drum central axis that is generated when the rotational driving force for rotationally driving the image bearing drum is received from the apparatus main body side. Therefore, it is possible to prevent the image bearing drum and the process means from being bent or eccentric due to the urging force, and to prevent the rotational driving of the image bearing drum and the process means from adversely affecting the image. ..

Further, since the bearing portion is located inside the process cartridge housing which integrally supports the image bearing drum and the process means, the image which becomes the most important at the time of coupling with the positioning shaft on the apparatus main body side. It is possible to prevent the positioning portion on the supporting drum side from being accidentally damaged or deformed, and protect the positioning portion. Therefore,
The positioning of the image bearing drum on the main body is always ensured.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a process cartridge and an apparatus main body to which an embodiment of the present invention is applied.

FIG. 2 is a partial cross-sectional view of a process cartridge and an apparatus main body to which an embodiment of the present invention is applied.

FIG. 3 is a partial cross-sectional view of a connecting portion of a process cartridge to which an embodiment of the present invention is applied.

FIG. 4 is a partial cross-sectional view of a connecting portion of a process cartridge to which an embodiment of the present invention is applied.

FIG. 5 is a partially broken sectional view of a connecting portion of a process cartridge to which an embodiment of the present invention is applied.

FIG. 6 is a perspective view of a process cartridge to which an embodiment of the present invention is applied.

FIG. 7 is a perspective view of a process cartridge to which an embodiment of the present invention is applied.

FIG. 8 is a sectional view of an electrophotographic copying machine to which the process cartridge of the present invention is applied.

FIG. 9 is a perspective view of a conventional process cartridge.

FIG. 10 is a cross-sectional view showing a combined state of a conventional process cartridge.

FIG. 11 is a partial cross-sectional view of a process cartridge and an apparatus main body to which another embodiment of the present invention is applied.

12 is a partial perspective view of an apparatus to which the embodiment shown in FIG. 11 is applied.

FIG. 13 is a partial cross-sectional view illustrating an example of a flange portion of a photosensitive drum to which the present invention has been applied.

FIG. 14 is a partial cross-sectional view illustrating an example of a flange portion of a photosensitive drum to which the present invention has been applied.

[Explanation of symbols]

 1 Photosensitive Drum 2 Flange 2b Gear Part 3 Cartridge Housing 4 Drum Drive Shaft 10 Drive Transmitter 13 Conductive Plate 14 Developer 14a, 15a Gear 15 Cleaning Device 19 Electrophotographic Copier 31 Cartridge Positioning Shaft 38 Press-fit Gear 39 Photosensitive Drum

Claims (12)

[Claims] 1. A process cartridge detachably mountable to an image forming apparatus main body, wherein a casing integrally supporting an image bearing drum and a process unit acting on the image bearing drum, and a casing located inside the casing. , When the process cartridge is loaded into the main body of the device, the bearing part that fits with the positioning shaft as the rotation center shaft for the image bearing drum attached to the main body of the device and the rotational driving force received by the image bearing drum are stored in the process cartridge. A drive transmission gear portion for transmitting to the process means, and the bearing portion and the drive transmission gear portion are located on the same cross section perpendicular to the rotation center axis direction of the image bearing drum, A process cartridge, wherein the bearing and the drive transmission gear are provided at an end of an image bearing drum. 2. The process cartridge according to claim 1, wherein the bearing portion and the drive transmission gear portion are provided on a flange member inscribed in an end portion of the image bearing drum. 3. The image forming apparatus wherein the process cartridge integrally includes at least one of a charging device, a developing device, and a cleaning device as the process means, and an electrophotographic photosensitive drum as the image carrying drum. The process cartridge according to claim 1, wherein the process cartridge is removable from the main body. 4. The process cartridge according to claim 2, wherein the flange member is provided with a driving force receiving portion that receives a rotational driving force for rotationally driving the image bearing drum from the apparatus main body side. 5. The flange member is an insulating flange member, and a conductive member is provided inside the image bearing drum so as to come into contact with the inner surface of the conductive substrate of the image bearing drum and the positioning shaft. The process cartridge according to 2 or 4. 6. An image forming apparatus using a process cartridge integrally supporting an image bearing drum and a process unit acting on the image bearing drum, wherein a casing integrally supporting the image bearing drum and the process unit. When the process cartridge is mounted inside the apparatus main body, the bearing portion fitted to the apparatus main body side and the positioning shaft as the rotation center axis for the image bearing drum, and the image bearing drum rotation driving force. And a driving force receiving gear portion that receives the rotational driving force for engaging with the gear portion on the apparatus main body side, and the driving force receiving gear portion is located on the same cross section perpendicular to the rotation center axis direction of the image bearing drum. Guide means for detachably guiding the process cartridge provided at the end of the image bearing drum, and a rotation center shaft for the image bearing drum fitted in the bearing portion. An image forming apparatus and the positioning axis of a drive means having a gear portion that gives rotational driving force to the image bearing drum meshes with the driving force receiving gear unit, characterized in that it has a. 7. The image forming apparatus according to claim 6, wherein the bearing portion and the driving force receiving gear portion are provided on a flange member inscribed in an end portion of the image bearing drum. 8. An image forming apparatus using a process cartridge integrally supporting an image bearing drum and a process unit acting on the image bearing drum, wherein an inside of a housing for integrally supporting the image bearing drum and the process unit. When the process cartridge is loaded in the apparatus main body, the bearing portion fitted to the positioning shaft as the rotation center axis for the image bearing drum mounted on the apparatus main body side, and the rotational driving force received by the image bearing drum. And a drive transmission gear portion for transmitting to the process means in the process cartridge, and these are provided at the end of the image bearing drum so as to be located on the same cross section perpendicular to the direction of the rotation center axis of the image bearing drum. A guide means for detachably guiding the process cartridge, a positioning shaft as a rotation center shaft for the image bearing drum fitted in the bearing portion, An image forming apparatus comprising: a driving unit that applies a rotational driving force to the supporting drum. 9. The image forming apparatus according to claim 8, wherein the bearing portion and the drive transmission gear portion are provided on a flange member inscribed in an end portion of the image bearing drum. 10. The image forming apparatus according to claim 9, wherein the flange member is provided with a driving force receiving portion that receives a rotational driving force for rotationally driving the image bearing drum from the apparatus main body side. 11. The flange member is an insulating flange member, and a conductive member is provided inside the image bearing drum so as to contact the inner surface of the conductive substrate of the image bearing drum and the positioning shaft. 9. The image forming apparatus according to 9 or 10. 12. An image forming apparatus using a process cartridge integrally supporting an image bearing drum and a process means acting on the image bearing drum, wherein a casing integrally supporting the image bearing drum and the process means. When the process cartridge is mounted inside the apparatus main body, the bearing portion fitted to the positioning shaft as the rotation center axis for the image carrying drum mounted on the apparatus main body side and the image carrying drum are rotationally driven. The driving force receiving gear portion for receiving the rotational driving force for meshing with the gear portion on the apparatus main body side, and the bearing drum so as to come into contact with the inner surface of the conductive substrate of the image bearing drum and the positioning shaft fitted to the bearing portion. A conduction member provided inside, and the bearing portion and the driving force receiving gear portion are perpendicular to the direction of the rotation center axis of the image bearing drum. Guide means for detachably guiding the process cartridge in which the bearing portion and the driving force receiving gear portion are provided at the end portion of the image bearing drum so as to be positioned on the cross section; A positioning shaft as a rotation center shaft for the image bearing drum that contacts the conduction member, and a driving unit having a gear portion that meshes with the driving force receiving gear portion and applies a rotational driving force to the image bearing drum. An image forming apparatus characterized by.