JP2001109356A - Process cartridge, image forming device and assembly of electrophotographic photoreceptor or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach/detach a process means to/from a photoreceptor drum whenever an image is formed for preventing the permanent deformation of the process means such as a charged roller with inexpensive constitution and without the need of the inverse rotation of the photoreceptor drum. SOLUTION: While a drum gear 39 engaged with a stopper driving gear 35b is rotated, a stopper member 35a slides with thrust force generated in a coupling part 135 between the projection 35c1 of a rotary member 35c and the hole 35b1 of the stopper driving gear 35b. When the drum gear 39 stops, the rotary member 35c continues rotation for a while which allows the coupling part to generate thrust force in a opposite direction and the stopper member 35a is returned to an original position. The attachment/detachment of a charged roller 8 to/from the photoreceptor drum 7 are controlled by the difference of the position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a laser beam printer or a copying machine, a process cartridge used in the image forming apparatus, and an assembly of an electrophotographic photosensitive member. About.

[0002]

2. Description of the Related Art A transfer type electrophotographic apparatus generally has the following means and image forming process. That is, an electrophotographic photosensitive member such as selenium, cadmium sulfide, zinc oxide, amorphous silicon, or an organic photoconductor, which is generally a rotating drum type as an image carrier, is used. The surface of the photoreceptor after charging is image-exposed by an image exposure unit to form an electrostatic latent image corresponding to the exposed image, and the electrostatic latent image is developed by a developing unit with toner of developer. The toner image is adhered and developed as a toner image, and the toner image is transferred to a transfer-receiving material, fixed by a fixing unit, and discharged as an image formed product (copy, print). After the transfer of the toner image to the material to be transferred, the rotating photoreceptor is subjected to removal of residual toner by a cleaning means (cleaner) and is repeatedly provided for image formation.

[0003] In a process cartridge in which these process means, that is, a charging means, a developing means, and a cleaning means, and an electrophotographic photosensitive member are made detachable from a printer or a copying machine main body, the initial setting state of the electrophotographic photosensitive member is And a process means disposed therearound, in particular, those in which a member in contact with an electrophotographic photosensitive member maintains a contact state, are widely known and put into practical use. In addition, a protective member is interposed between the electrophotographic photosensitive member and other abutting members to prevent dents due to vibration or dropping, and the abutment is turned on and off in conjunction with the operation of attaching and detaching the process cartridge to and from the printer body. What causes them to be known.

[0004]

However, in the above-mentioned conventional example, there are a cleaning member, a contact charging member, a developing member, and the like as members which are kept in contact with an electrophotographic photosensitive member, particularly a photosensitive drum made of an organic photosensitive member. If these are left and stored in an unused state of the process cartridge, various problems described below may occur.

In a cleaning blade having an edge portion as the cleaning member, pressure is concentrated on the edge portion, and irregularities are generated on the surface layer of the photosensitive drum in contact with the edge portion. Regardless of reversal development, a horizontal line may occur on an image regardless of image formation.

Further, in the case of a cleaning blade made of rubber or the like as a cleaning member, the pressing force against the photosensitive drum is given by the displacement and deformation of the blade itself, so that the blade itself is permanently deformed and the pressing force is reduced. However, in some cases, cleaning failure or residual toner on the photosensitive drum cannot be removed, resulting in image contamination.

[0007] Even in the case of the roller or blade as the contact charging member, compression deformation or permanent deformation due to pressure contact of the roller itself or the blade may occur, thereby deteriorating the uniformity of charging and causing an image defect.

Further, in the contact type developing sleeve as the developing member, unevenness in the pitch of the press contact portion occurs in the image due to defective coating of the toner and displacement of the press contact in the developing portion due to the compression deformation of the contact nip portion itself. There was a case.

As one method for preventing this, even in a type of process cartridge in which each process means is separated and attached in accordance with attachment and detachment of the process cartridge main body, the process cartridge is manufactured and manufactured until the user starts using it. Although it is possible to avoid contact with the process means, measures must be taken for long-term non-use after starting use, it must be selected from materials that are unlikely to deform the process means, Material selection was difficult.

Further, when an image is formed by a method of moving the photosensitive drum away from the photosensitive drum using a solenoid clutch, or a method of rotating the photosensitive drum in a direction opposite to that at the time of image formation in order to move the process means. However, in a process cartridge adopting a mechanism for contacting the process means, no image defect occurs due to leaving as described above.
However, electric components such as a solenoid clutch lead to an increase in cost, and the method of rotating the photosensitive drum in the reverse direction causes a problem that the cleaning means in contact with the photosensitive drum does not remove the residual toner.

In general, the rotating portion of the developing device which always supplies an appropriate amount of toner to the photosensitive drum is also synchronized with the rotation of the photosensitive drum. Unnecessary toner may be discharged and spilled. In order to prevent this, if a one-way clutch or the like is attached so that the photosensitive drum rotates in synchronization only with the rotation direction at the time of image formation, the cost is increased.

Accordingly, it is an object of the present invention to provide an electrophotographic photosensitive member having an inexpensive structure, which does not require reverse rotation of the electrophotographic photosensitive member, and which prevents permanent deformation of the process means. It is an object of the present invention to provide an assembly such as a process cartridge, an image forming apparatus, and an electrophotographic photosensitive member which can be brought into contact with and separated from the photosensitive drum.

[0013]

The above object is achieved by an assembly of a process cartridge, an image forming apparatus, an electrophotographic photosensitive member and the like according to the present invention. In summary, the present invention is detachable from the main body of the image forming apparatus, and at least an electrophotographic photosensitive member, a process means acting on the electrophotographic photosensitive member, and rotating integrally or synchronously with the electrophotographic photosensitive member. A thrust generating member that meshes with the gear, a rotating member having an inertial force that engages with the thrust generating member, and an axially movable member that is provided integrally with the rotating member. A stopper member, when receiving rotation driving, moves the stopper member from the first position to the second position, and when the rotation of the electrophotographic photosensitive member stops, the rotating member transfers kinetic energy. The process cartridge is characterized in that it continues to rotate until it is lost, and the stopper member is returned from the second position to the first position.

According to another aspect of the present invention, at least an electrophotographic photosensitive member, processing means acting on the electrophotographic photosensitive member, and a gear rotating integrally or synchronously with the electrophotographic photosensitive member are provided. A thrust generating member meshing with the gear, a rotating member having an inertial force engaged with the thrust generating member, and a stopper member provided integrally with the rotating member and movable in the axial direction. When receiving the rotation drive, the stopper member is moved from the first position to the second position, and when the rotation of the electrophotographic photosensitive member stops, the stopper member rotates until the rotating member loses kinetic energy. And the stopper member is returned from the second position to the first position.

According to another aspect of the present invention, at least an electrophotographic photosensitive member, a process means acting on the electrophotographic photosensitive member, and a gear rotating integrally or synchronously with the electrophotographic photosensitive member. A thrust generating member meshing with the gear, a rotating member having an inertial force engaged with the thrust generating member, and a stopper member provided integrally with the rotating member and movable in the axial direction. When receiving the rotation drive, the stopper member is moved from the first position to the second position, and when the rotation of the electrophotographic photosensitive member stops, until the rotating member loses kinetic energy. An assembly is provided wherein rotation continues and the stopper member is returned from the second position to the first position.

In the above invention, in the thrust generating member, a drag is generated at a contact portion with another drive transmitting portion at the time of driving transmission, and the contact portion has a first tapered shape for directing the drag in a thrust direction. Has, the first tapered shape is a shape in which the thrust generating member and the other drive transmission unit generate a thrust force in a direction away from each other or in a direction attracting each other when the electrophotographic photosensitive member rotates,
The stopper member moves from the first position at the time of rotation stop to the second position by the thrust force, and when the electrophotographic photoreceptor stops, the stopper member rotates until the rotary member loses kinetic energy. Subsequently, it is preferable that a drag is generated between the first tapered shape and a second tapered shape that generates a reverse thrust force, and the stopper member is returned to the first position.

Further, the thrust generating member and the rotating member are connected by a twisted hole having a polygonal cross section and a twisted polygonal projection which fits into the hole. It rotates by receiving the driving force from the gear,
The stopper member is moved from the first position when the rotation is stopped to the second position by the axial force generated at the fitting portion, and when the rotation of the electrophotographic photosensitive member is stopped,
The stopper member also stops, while the rotating member continues to rotate until it loses the energy of rotation, so that the axial force generated at the fitting portion acts in the opposite direction to the rotation of the electrophotographic photosensitive member, and the stopper Preferably, a member is returned from said second position to said first position.

Further, according to another aspect of the present invention, there is provided:
A process cartridge detachable from the image forming apparatus main body and having at least an electrophotographic photosensitive member, a process unit acting on the electrophotographic photosensitive member, and a helical gear rotating integrally or synchronously with the electrophotographic photosensitive member. A helical gear with a stopper and a rotating member having an inertia force, wherein a helical gear with a stopper is provided.
When receiving driving, a thrust force is generated at a meshing portion with another helical gear, and the helical gear with stopper moves from the first position at the time of rotation stop to the second position by the thrust force, while When the electrophotographic photoreceptor stops, the rotating member continues to rotate until it loses kinetic energy, generates a thrust force in a direction opposite to the moving direction, and the helical gear with the stopper is returned to the first position. Is provided.

According to another aspect of the present invention, at least an electrophotographic photosensitive member, processing means acting on the electrophotographic photosensitive member, and a helical gear rotating integrally or synchronously with the electrophotographic photosensitive member are provided. An image forming apparatus having a helical gear having a stopper integrally formed with a helical gear engaged with the helical gear, and a rotating member having an inertial force, wherein the helical gear with a stopper is connected to another helical gear when driven. A thrust force is generated at the meshing portion, and the helical gear with the stopper moves from the first position at the time of rotation stop to the second position by the thrust force, while, when the electrophotographic photosensitive member stops, the The rotating member continues to rotate until it loses kinetic energy, and generates a thrust force in a direction opposite to the moving direction, thereby stopping the stop. Chromatography with helical gears image forming apparatus is provided, characterized in that is returned to the first position.

According to another aspect of the present invention, at least an electrophotographic photosensitive member, a process means acting on the electrophotographic photosensitive member, and a helical gear rotating integrally or synchronously with the electrophotographic photosensitive member. An assembly having a helical gear with a stopper integrally formed with a stopper member that meshes with the helical gear, and a rotating member having an inertial force, wherein the helical gear with the stopper is separated from other helical gears when driven. A thrust force is generated at the meshing portion of the helical gear, and the helical gear with the stopper moves from the first position at the time of rotation stop to the second position by the thrust force, while, when the electrophotographic photosensitive member stops, The rotating member continues to rotate until it loses kinetic energy, and generates a thrust force in a direction opposite to the moving direction, and Assembly, characterized in that over with helical gear is returned to the first position is provided.

In the above invention, it is preferable to utilize the fact that the stopper member is at a different position between the first position when the electrophotographic photosensitive member is stopped and the second position while the electrophotographic photosensitive member is rotating. It is preferable to control the operation of contacting / separating or releasing the pressure contact between the electrophotographic photosensitive member and the process means.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an assembly of a process cartridge, an image forming apparatus, an electrophotographic photosensitive member, and the like according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS.

First, an electrophotographic image forming apparatus and a process cartridge according to this embodiment will be described with reference to FIGS. FIG. 1 is an explanatory view showing the overall configuration of an electrophotographic image forming apparatus in which a process cartridge is mounted, FIGS. 2 and 3 are explanatory views of the configuration of the process cartridge, and FIG. FIG. 4 is an explanatory diagram for explaining a state of being attached to a main body.

As shown in FIG. 1, an electrophotographic image forming apparatus A of this embodiment forms an image on a recording medium 2 by an electrophotographic image forming process. Photoreceptor (hereinafter, "photoreceptor drum")
7) to form a toner image. Then, in synchronization with the formation of the toner image, the recording medium 2 set on the transport tray 3a is transported by the transport unit 3 including the pickup roller 3b and the transport roller 3c.

Next, a voltage is applied to the transfer roller 4 as a transfer means for transferring the toner image formed on the photosensitive drum 7 of the process cartridge B to the recording medium 2.
Transfer to Thereafter, the recording medium 2 of the toner image is
In step d, the sheet is conveyed to the fixing unit 5. The fixing unit 5 includes a driving roller 5a and a fixing rotator 5b having a built-in heater, and applies heat and pressure to the recording medium 2 passing therethrough to fix the transferred toner image. Then, this recording medium 2
Is conveyed reversely by the paper discharge rollers 3 e and 3 f and discharged to the discharge tray 6.

On the other hand, as shown in FIGS. 1 and 2, the process cartridge B rotates a photosensitive drum 7 having a photosensitive layer as an image carrier, and applies a voltage to a charging roller 8 as charging means. It is uniformly charged by application. Next, a laser beam corresponding to the image information from the optical system 1 is irradiated onto the photosensitive drum 7 through the exposure opening 9 to form a latent image. The latent image is developed by the developing unit 10 using toner. That is, the charging roller 8 is provided in contact with the photosensitive drum 7 and charges the photosensitive drum 7. The developing unit 10 supplies toner to a developing area of the photosensitive drum 7 to develop the latent image formed on the photosensitive drum 7. The optical system 1 has a laser diode 1a, a polygon mirror 1b, a lens 1c, and a reflection mirror 1d.

The developing means 10 supplies the toner in the toner chamber 10a to the developing chamber 10b, rotates the developing roller 10c attached to the developing chamber 10b, and removes the toner layer provided with the triboelectric charge by the developing blade 10d. Formed on the surface of the developing roller 10c having a fixed magnet built therein,
The toner is supplied to a developing area of the photosensitive drum 7. Then, the toner is transferred to the photosensitive drum 7 in accordance with the latent image, thereby forming a toner image and visualizing the toner image.

Next, after applying a voltage having a polarity opposite to that of the toner image to the transfer roller 4 to transfer the toner image formed on the photosensitive drum 7 to the recording medium 2, the cleaning means 11
As a result, the residual toner on the photosensitive drum 7 is removed. Here, the cleaning means 11 scrapes off the toner remaining on the photosensitive drum 7 by the elastic cleaning blade 11a and collects it in the removed toner reservoir 11b.

Each component such as the photosensitive drum 7 is housed in a cartridge frame formed by connecting the toner developing frame 12, the toner developing wall member 13, and the cleaning frame 14, to form a cartridge. That is, the toner developing frame 12 and the toner developing wall member 13 are welded to form the toner chamber 10a and the developing chamber 10b.
b, a developing roller 10c and a developing blade 10d are attached. Each member constituting the photosensitive drum 7, the charging roller 8, and the cleaning unit 11 is attached to the cleaning frame 14. The process cartridge B is constituted by swingably connecting the toner developing frame 12 and the cleaning frame 14.

The process cartridge B has an exposure opening 9 for irradiating the photosensitive drum 7 with light corresponding to image information and a transfer opening 15 for facing the photosensitive drum 7 to the recording medium 2. is there. And both openings 9, 1
A shutter member 16 capable of opening and closing the shutter 5 is attached. That is, the transfer opening 15 is for transferring the toner image formed on the photosensitive drum 7 to the recording medium 2.

As shown in FIG. 4, the image forming apparatus A has an opening / closing cover 18 attached to an apparatus main body 17 so as to be rotatable about a shaft 19. When the opening / closing cover 18 is opened, a guide member (rail groove) (not shown) for guiding the process cartridge B is provided inside the apparatus main body 17. Then, the operator attaches and detaches the process cartridge B along the guide member. At this time, as shown in FIG. 3, the first projection 24 and the second projection 25 provided on the end wall in the longitudinal direction of the process cartridge B are guided along the guide member (not shown) of the apparatus main body 17 described above. .

As shown in FIGS. 2 and 3, the shutter member 1
Numeral 6 has a first shutter portion 16a fixed to a rotatably supported rotation support portion 16c and a second shutter portion 16e supported by an arm portion 16d.
c, the first shutter 16a closes the exposure opening 9 by the spring force of the torsion coil spring 23 attached to the second shutter 1
6b is urged to close the transfer opening 15, and when the process cartridge B is outside the apparatus main body 17, the first
The shutter 16a and the second shutter 16b close the exposure opening 9 and the transfer opening 15, respectively.

When the process cartridge B is mounted on the apparatus main body with the handle member 26 integrally with the cleaning frame 14, the longitudinal end of the arm 16d supporting the second shutter 16b covering the photosensitive drum 7 is disposed outside. In a state where the locking projection 16e projecting toward the main body is in contact with the apparatus main body and the further entry into the cartridge mounting portion is stopped, the first and second protrusions 24 and 25 of the process cartridge B The shutter member 16 is moved to the position where the exposure opening 9 and the transfer opening 15 are opened as shown in FIG. On the other hand, when the process cartridge B is removed from the apparatus main body 17, the shutter member 16 is moved by the spring force of the torsion coil spring 23 to expose the exposure opening 9 and the transfer opening 15.
Close.

Next, the charging roller will be described with reference to FIG.

The charging roller 8 has a structure in which a core metal (conductive base) 8a mainly composed of SUS is surrounded by a resistance layer 8b. The resistance layer 8b has a coating layer 8c as a surface layer, and an elastic layer 8d thereunder. The charging roller 8 is in contact with the photosensitive drum 7 by a biasing member 21 such as a coil spring via a bearing 20 made of a conductive layer member to form an electric circuit. In addition, power is supplied from a power source (not shown) to the charging roller 8 via a bearing 20, charging is performed via a nip portion 22 with the photosensitive drum 7, and as the photosensitive drum 7 moves in the L <b> 1 direction, The body drum 7 is uniformly charged.

Next, features of the present invention will be described. FIG. 6 is a view for explaining the stopper mechanism according to the present invention.

The stopper mechanism 35 of this embodiment is a stopper driving gear 35b which is a thrust generating member for obtaining a rotational driving force by meshing with a drum gear 39 (see FIG. 10) fixed to the end of the photosensitive drum 7, and driving the stopper. Axial stopper member 35 provided integrally with gear 35b
a, and a rotating member 35c that rotates while being supported by a fixed shaft (not shown) together with the stopper driving gear 35b.

As a member associated with the stopper mechanism 35, a bearing guide 3 for guiding a stopper member 35a is provided.
1 is provided in the apparatus main body.

Stopper drive gear 25b and rotating member 35
c transmits power by a method of generating a thrust force by a drag generated at a contact portion of each other. As shown in FIG. 6, the rotating member 35c is provided with a twisted triangular prism having a triangular cross section, that is, a tapered projection 35c1. The stopper driving gear 35b has a twisted hole 35 fitted with the twisted triangular prism projection 35c1.
b1 is formed.

The shapes of the twisted triangular prism projection 35c1 and the twisted hole 35b1 can function even if the cross section is not triangular. Further, the protrusion 35c1 and the hole 35b1 of the triangular prism are connected to the stopper driving gear 35b side and
It works on either side of 5c.

This twisted triangular prism projection 35c1 and hole 3
5b1 is fitted to apply a rotational force to the stopper drive gear 35b. Twisted triangular prism protrusion 35c1 and hole 35b
No. 1 fitting portion (hereinafter referred to as “coupling portion”) 135
When the drag occurs, the stopper driving gear 35b and the rotating member 35c are arranged so that a thrust force is generated in a direction away from each other.

Next, a state where the stopper mechanism 35 is rotating and stopped will be described with reference to FIG.

FIG. 7A shows a state in which the photosensitive drum 7, that is, the drum gear 39 and the stopper 35 mechanism are completely stopped. At this time, the coupling portion 135 is in the coupled state, and the stopper driving gear 35b is separated from the bearing guide portion 31.

When the drum gear 39 rotates, the stopper driving gear 35b rotates, thereby causing the coupling portion 1 to rotate.
As shown in FIG. 7 (b), the stopper driving gear 35b is moved together with the stopper portion 35a by an arrow a.
It slides in the direction until it hits the bearing guide part 31. When the drum gear 39 continues to rotate, it stays at this position.

In FIG. 7C, at the same time as the rotation of the drum gear 39 stops, the stopper driving gear 35b also stops. Rotating member 3 connected by coupling portion 135
5c stops after rotating until there is no more rotational energy. Due to the rotation due to the inertial force, the coupling unit 135 generates a force in the opposite direction (the direction of the arrow b) to the axial force (the direction of the arrow a) generated during the continuous rotation of the photosensitive drum 7. Under this force, the stopper portion 35a slides in the direction of arrow b.

According to this principle, during continuous rotation of the drum gear 39, the stopper portion 35a slides in the direction of arrow a, and when stopped, slides in the direction of arrow b and returns to the original position.

The axial force generated at the coupling portion 135 between the projection and the hole of the triangular prism will be described with reference to FIG. FIG. 8 shows a twisted triangular prism protrusion 35c1 and a hole 35b.
Only the peripheral portion where No. 1 is fitted is shown.

FIG. 8 (a) shows a state in which the stopper mechanism 35 is stopped and the twisted triangular prism projection 35c1 is
No contact is made with the wall surface on the b1 side, and no thrust force is applied. As shown in FIG. 8B, when the twisted hole 35b1 side is rotated in the direction of the arrow, the twisted triangular prism protrusion 3 is formed.
5c1 contacts the wall surface C side of the hole 35b1. At this time, since the rotating member 35c having an inertial force is integrally attached to the twisted triangular prism protrusion 35c1, the rotating member 3
Drag is generated in the coupling portion 135 until 5c reaches a constant speed. Since the wall surface of the hole 35b1 of the coupling portion 135 is twisted, a force is generated to separate the coupling portion 135 in the axial direction.

FIG. 8C is a view immediately after the rotation of the photosensitive drum 7 is stopped, that is, immediately after the stopper driving gear 35b having the twisted hole 35b1 is stopped. Even if the hole 35b1 side of the coupling portion 135 stops, the triangular prism projection 35 integrated with the rotating member 35c having inertia force.
c1 tries to keep rotating. Then, it comes into contact with the wall surface D side of the hole 35b1. At this time, a drag is generated in the coupling portion 135 and is converted into an axial force by the twisted shape of the wall surface, thereby generating a force attracting each other in the axial direction. With this force, the stopper portion 35a is pulled back and returns to FIG.

The stopper mechanism 3 shown in FIGS. 7 and 8
In the case of 5, a force that slides the stopper portion 35a during rotation, that is, a drag force can be generated in the coupling portion 135. FIG. 9 shows a configuration in which the coupling portion 135 generates a drag even when the photosensitive drum 7 reaches a constant rotation speed.

A load is provided by pressing a friction member 37 such as felt against a side receiving the force of the coupling portion 135 with a compression coil spring 38. Since the driven side always has a load during rotation, the coupling portion 13 is constantly rotated during rotation.
5 can generate a drag. However, this load is applied to the rotating member 35 after the rotation of the photosensitive drum 7 has stopped.
Therefore, the rotation member 35c needs to have a sufficient inertia force.

Next, a case where the above-described stopper mechanism 35 is applied as separation control means for separating the charging roller 8 from the photosensitive drum 7 will be described with reference to FIGS.

The separation control means of this embodiment includes a stopper mechanism 35 and a toothless gear 39 which is fitted to the metal core 8 a of the charging roller 8 and meshes with the drum gear 39.

The inter-axis distance when the missing tooth gear 34 meshes with the drum gear 39 is configured to be larger than the inter-axis distance when the charging roller 8 is pressed against the photosensitive drum 7.

FIG. 10 shows that the missing tooth gear 34 is the drum gear 3
7, the charging roller 8 is separated from the photosensitive drum 7.

When the drum gear 39 receives a driving force from the image forming apparatus main body, the stopper driving gear 35b meshing with the photosensitive drum 7 and the drum gear 39 rotates. Also,
The charging roller 8 and its core bar 8a rotate following the rotation of the photosensitive drum 7 or by another driving source. Core 8
The toothless gear 34 fitted with a receives a frictional force from the core bar 8a, and uses this frictional force as a drive source.

FIG. 11 shows a state during image formation. When the drum gear 39 is rotating, the stopper member 35a slides in the direction of arrow a in the figure and enters the rotation plane of the toothless gear 34, thereby stopping the rotation of the toothless gear 34. This state is maintained while the drum gear 39 is rotating. At this time, the missing tooth gear 34 cannot mesh with the drum gear 39. That is, since there is no member that regulates the distance between the axis of the charging roller 8 and the photosensitive drum 7, the charging roller 8 is pressed against the photosensitive drum 7 by the force of the urging member 21 (see FIG. 5). An image is formed.

The sequence of the operation for separating the charging roller 8 will be described. The separation operation is completed by temporarily stopping the rotation of the drum gear 39 after the image formation, and then rotating the drum gear 39 again by a predetermined angle. FIG.
The state immediately after the drum gear 39 after the image formation is stopped. First, when the rotation of the drum gear 39 is stopped,
The stopper member 35a slides in the direction of arrow b in the figure. In this state, the rotation regulation of the toothless gear 34 is released. However, the missing tooth gear 34 has stopped at the position where the drum gear 39 has stopped, and has not yet engaged with the drum gear 39. That is, the charging roller 8 is still in pressure contact with the photosensitive drum 7.

FIG. 13 shows a state in which the drum gear 39 is once again rotated to separate the charging roller 8.

At this time, the stopper member 35a slides again into the plane of rotation of the toothless gear 34,
Since the toothless gear 34 starts rotating simultaneously with the start of rotation of the drum gear 39, the rotation of the toothless gear 34 cannot be stopped. When the drum gear 39 is rotated by an angle at which the missing tooth gear 34 rotates and meshes with the drum gear 39 to bring the charging roller 8 to a completely separated position, the drum gear 39 is stopped. When stopped, the charging roller 8 shown in FIG. 10 returns to the separated state.

As described above, according to the present embodiment, in the means for separating the charging roller from the photosensitive drum except for the time of image formation, the stopper driving gear, Using the stopper mechanism including the stopper member and the rotating member, the stopper member is slid by the thrust force generated in the coupling portion 135 between the stopper driving gear and the rotating member during rotation of the photosensitive drum, and the photosensitive drum is rotated. When the rotation stops, the rotating member continues to rotate for a while and the coupling portion 1
The operation of generating a reverse thrust force at 35 and returning the stopper member to the original position allows the photosensitive drum of the charging roller to be used without using an electric component such as a solenoid and reversely rotating the photosensitive drum. Can be attached and detached.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIGS.
5 will be described.

In the first embodiment, the case where the stopper mechanism 35 according to the present invention is applied to the separation / contact control means of the charging roller 8 with respect to the photosensitive drum 7 has been described. In the present embodiment, as shown in FIG. , The stopper mechanism 35 and the toothless gear 34 are connected to the charging roller 8 as a process means.
In addition, it is configured to be attached to each core metal of the developing roller 10c and the transfer roller 4.

During the rotation drive, each process means
When the toothless gear 34 is engaged with the photoconductor drum 7 and is engaged with the photoreceptor drum 7, as shown in FIG. 15, the respective process means 8, 10c, and 4 can be separated from the photoconductor drum 7 in the direction of the arrow. . The description of the operation principle and procedure is omitted.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG.

The stopper mechanism 45 of this embodiment has a different structure from the stopper mechanism 35 of the first embodiment, but the operation is the same.

In this embodiment, in order to generate a thrust force, a stopper driving gear 45b which is a thrust generating member is used.
A twisted groove 45b1 is formed on the side, and a projection 45c1 that engages while rotating in the groove 45b1 is mounted on the rotating member 45c side.

When the stopper driving gear 45b rotates in the rotation direction indicated by the arrow in the drawing, the projection 45c1 is turned into the groove 45b1.
And the thrust force is generated in a direction in which the stopper driving gear 45b side and the rotating member 45c side are separated from each other. After the stopper drive gear 45b stops, the rotating member 45c continues to rotate, and the protrusion 45c1 comes into contact with the D side of the groove 35b1 to generate a thrust force in a direction to attract each other.

Embodiment 4 Next, a fourth embodiment of the present invention will be described with reference to FIG.

The stopper mechanism 65 of this embodiment is similar to that of FIG.
As shown in (1), there is provided a configuration using the thrust force generated by the helical gear.

The stopper driving gear 65b is a helical gear, and is driven by a drum gear 69 which is also a helical gear. The stopper drive gear 65b and the stopper member 65a are integral parts. When the drum gear 69 and the stopper driving gear 65b mesh with each other, a thrust force is generated by the twisted tooth surface of the boss.

During the rotation of the drum gear 69, the stopper member 65a slides in the direction of arrow a by this thrust force. After the rotation of the drum gear 69 stops, the kinetic energy of the rotating member 65c causes the stopper drive gear 65b to rotate the drum gear 69 (the drum gear does not rotate). Since the force transmission / reception relationship is reversed when the drum gear 69 is rotating, the thrust force generated on the tooth surface of the lance is also reversed. This causes the stopper member 65a to slide in the direction of arrow b.

Embodiment 5 Next, a fifth embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 18, the charging roller separation control means of this embodiment is provided with a spring clutch 42 coaxially with the photosensitive drum 7 together with the stopper mechanism 35 described in the first embodiment. It is characterized by.

The spring clutch 42 of this embodiment has a substantially cylindrical spring clutch control section 42b. One end, that is, the input side remote from the photosensitive drum 7, has an input gear engaged with the stopper drive gear 35b. The charging roller 8a is fixed to the other end, ie, the output side.
A cam 42c that engages with the cored bar 8a is fixed, and a projection 42d that comes into contact with and separates from the stopper member 35a that moves forward and backward is provided on the spring clutch control unit 42b.

FIG. 18 shows that the charging roller 8 is
Represents a state in which it is separated from.

FIG. 19 shows a state in which an image is being formed. The cam 42c is stopped at a position where the cam 42c does not come into contact with the metal core 8a of the charging roller 8 and does not stop. More specifically, when the drive transmission of the spring clutch 42 is being performed, the input gear 42a, the spring clutch control unit 42b, and the cam 42c rotate simultaneously. When the rotation starts, the stopper member 35a slides in the direction of the arrow a, the projection 42d hits the stopper member 35a, and the rotation stops, the drive transmission of the spring clutch 42 is cut off, and the rotation of the cam 42c stops immediately.

Here, the sequence of the operation for separating the charging roller 8 from the photosensitive drum 7 will be described.

During image formation, that is, when the photosensitive drum 7 is continuously rotating, as shown in FIG. 19, the stopper member 35a slides in the direction of arrow a, and the stopper driving gear 35b comes to a position where it abuts the guide 32. is there. At this position, the rotation of the projection 42d of the spring clutch 42 is stopped. Since the stop position of the cam 42c is determined by the phase with the projection 42d, it always stops at the same position.

FIG. 20 shows a state immediately after the image formation is temporarily stopped. At this time, similarly to the first embodiment, the stopper member 35a is a compression coil spring 35e (see FIG. 12).
Slides in the direction of arrow b by the force of. This allows
There is no restriction on the rotation of the projection 42d of the spring clutch 42.

FIG. 21 shows how the input gear 42a is rotated again to rotate the cam 42c.

Since the position where the cam 42c is stopped can be calculated from the phase with the projection 42d of the spring clutch 42, the amount of rotation at this time can cause the cam 42c to separate the charging roller 8 from the photosensitive drum 7. Rotate by the amount that comes to the position. By stopping the rotation of the input gear 42a at this position, the separated state can be maintained.
Return to the state.

As described above, the same operation and effect as in the first embodiment can be obtained by the operation of the stopper mechanism 35 and the spring clutch 42.

In this embodiment, the case where the present invention is applied to the separation mechanism of the charging roller has been described. However, as described in the second embodiment, the present invention can be applied to the developing sleeve and the transfer roller.

Embodiment 6 Next, a sixth embodiment of the present invention will be described with reference to FIG.

In the above-described embodiment, the present invention has been described with respect to the example in which the photosensitive drum 7 is provided as the electrophotographic photosensitive member of the process cartridge. However, as in this embodiment, the photosensitive belt 19 is provided as the electrophotographic photosensitive member. It can also be applied when

In the case of this embodiment, the photosensitive belt 19 is stretched over five rollers 7c and rotates in the direction of arrow f, during which uniform charging by the charging roller 8, exposure by the optical system 1, and developing device 10 The image formation is performed by the same process as that described in the first embodiment, such as development by the transfer roller 4, transfer by the transfer roller 4, and cleaning by the cleaning device 11. Therefore, a detailed description of the image forming process is omitted.

[0089]

As is apparent from the above description, according to the assembly of the process cartridge, the image forming apparatus and the electrophotographic photosensitive member of the present invention, the gear rotating integrally with or synchronously with the electrophotographic photosensitive member. A thrust generating member meshing with the thrust generating member, a rotating member having an inertial force engaged with the thrust generating member, and a stopper member provided integrally with the rotating member and movable in the axial direction. Moving the stopper member from the first position to the second position, when the rotation of the electrophotographic photosensitive member stops,
Continue rotating until the rotating member loses kinetic energy,
By returning the stopper member from the second position to the first position, it is possible to prevent the electrophotographic photoreceptor from rotating in the reverse direction and to prevent permanent deformation of the process means by using an inexpensive structure, and to form an image. Each time the process means can be brought into contact with or separated from the electrophotographic photosensitive member, a high-quality image can be obtained, the material of the process means can be easily selected, and the scattering of toner can be prevented.

The helical gear with a stopper includes a helical gear having a stopper integrally formed with a helical gear rotating with the electrophotographic photosensitive member or rotating with the helical gear, and a rotating member having an inertial force. When receiving the drive, a thrust force is generated at a meshing portion with another helical gear, and the helical gear with the stopper is moved from the first position at the time of rotation stop to the second position by the thrust force, When the electrophotographic photosensitive member stops, the rotating member continues to rotate until it loses kinetic energy, generates a thrust force in a direction opposite to the moving direction, and the helical gear with the stopper is returned to the first position. The same operation and effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an image forming apparatus equipped with a process cartridge according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the process cartridge of FIG.

FIG. 3 is an external perspective view of the process cartridge of FIG. 2;

FIG. 4 is an explanatory diagram showing a state in which an open / close cover of the image forming apparatus of FIG. 1 is opened and a process cartridge is mounted.

FIG. 5 is a sectional view showing a charging roller of the process cartridge of FIG. 2;

FIG. 6 is an exploded view showing the stopper mechanism of the first embodiment.

FIG. 7 is an explanatory view showing the operation of the stopper mechanism of the first embodiment.

FIG. 8 is a diagram for explaining the operation principle of the stopper mechanism of the first embodiment.

FIG. 9 is a diagram for explaining a thrust force generated in the stopper mechanism of the first embodiment.

FIG. 10 is a perspective view illustrating a state in which the charging roller is separated from the photosensitive drum, in which the stopper mechanism according to the first embodiment is applied to a charging roller separation control unit.

FIG. 11 is a perspective view showing a state during image formation of the stopper mechanism in the first embodiment.

FIG. 12 is a perspective view showing a state immediately after the drum gear stops after image formation in the first embodiment.

13 is a perspective view showing a state in which the drum gear is further rotated to separate the charging roller from the state of FIG. 12 in the first embodiment.

FIG. 14 is an explanatory view showing a state during image formation in which the stopper mechanism of the first embodiment is further applied to a developing sleeve and a transfer roller in the second embodiment.

15 shows a state in which the image forming apparatus shown in FIG.
FIG. 4 is an explanatory diagram illustrating a state in which a developing sleeve and a transfer roller shift to a separated state.

FIG. 16 is an exploded view showing a stopper mechanism in the third embodiment.

FIG. 17 is an exploded view showing a stopper mechanism in the fourth embodiment.

FIG. 18 is a perspective view illustrating a state in which a charging roller is separated from a photosensitive drum, in which a stopper mechanism and a spring clutch according to a fifth embodiment are applied to a charging roller separation control unit.

FIG. 19 is a perspective view showing a state during image formation of a stopper mechanism and a spring clutch in a fifth embodiment.

FIG. 20 is a perspective view showing a state immediately after the drum gear stops after image formation in the fifth embodiment.

FIG. 21 is a perspective view showing a state in which the drum gear is further rotated to separate the charging roller from the state of FIG. 20 in the fifth embodiment.

FIG. 22 is a schematic configuration diagram illustrating an image forming apparatus including a photosensitive belt according to a sixth embodiment.

[Explanation of symbols]

Reference Signs List 4 transfer roller (transfer unit / process unit) 7 photoconductor drum (electrophotographic photoconductor) 8 charging roller (charging unit / process unit) 10 developing device 10c developing sleeve (process unit) 19 photoconductor belt (electrophotographic photoconductor) 35, 45, 65 Stopper mechanism 35a, 45a, 65a Stopper member 35b, 45b, 65b Stopper drive gear (thrust generating member) 35c, 45c, 65c Rotating member

Claims (15)

[Claims] An electrophotographic photoreceptor detachable from the main body of the image forming apparatus, a process unit acting on the electrophotographic photoreceptor, and a gear rotating integrally or synchronously with the electrophotographic photoreceptor; A thrust generating member that meshes with the gear, a rotating member having an inertial force that engages with the thrust generating member, and a stopper member that is provided integrally with the rotating member and that can move in the axial direction. When receiving the rotation drive, the stopper member is moved from the first position to the second position, and when the rotation of the electrophotographic photosensitive member stops, the stopper member rotates until the rotating member loses kinetic energy. Wherein the stopper member is returned from the second position to the first position. 2. In the thrust generating member, a drag is generated at a contact portion with another drive transmitting portion at the time of driving transmission, and the contact portion has a first tapered shape for directing the drag in a thrust direction. The first tapered shape is a shape in which the thrust generating member and the other drive transmission portion generate a thrust force in a direction in which the thrust generating member and the other drive transmitting portion are separated from each other or in a direction in which they are attracted to each other when the electrophotographic photosensitive member is rotated. The thrust force moves from the first position at the time of rotation stop to the second position, while when the electrophotographic photoreceptor stops, the rotation member continues to rotate until it loses kinetic energy, A reaction force is generated between the first tapered shape and a second tapered shape that generates a reverse thrust force, and the stopper member is returned to the first position. The process cartridge according to claim 1, wherein 3. The thrust generating member and the rotating member are connected by a twisted hole having a polygonal cross section and a twisted polygonal protrusion fitted therein, and the thrust generating member and the rotating member are rotated when the electrophotographic photosensitive member is rotated. The stopper member is rotated from a first position at the time of rotation stop to a second position by the rotation of the electrophotographic photosensitive member when the stopper member is rotated by an axial force generated at the fitting portion. When the stopper stops, the stopper member also stops, while the rotating member continues to rotate until it loses the energy of rotation, so that the axial force generated in the fitting portion is in the opposite direction to the rotation of the electrophotographic photosensitive member. 2. The process cartridge according to claim 1, wherein said stopper member is returned from said second position to said first position. 4. An electrophotographic photosensitive member detachable from the image forming apparatus main body, at least an electrophotographic photosensitive member, process means acting on the electrophotographic photosensitive member, and a helical gear rotating integrally or synchronously with the electrophotographic photosensitive member. A process cartridge having a helical gear with a stopper integrally formed with a stopper member that meshes with the helical gear, and a rotating member having an inertial force. A thrust force is generated at the meshing portion, and the helical gear with the stopper moves from the first position at the time of rotation stop to the second position by the thrust force. Continue rotating until the rotating member loses kinetic energy, generating a thrust force in the direction opposite to the moving direction, A process cartridge, wherein a serial stoppered helical gear is returned to the first position. 5. Using the fact that the stopper member is at a different position between a first position during stop of the electrophotographic photosensitive member and a second position during rotation of the electrophotographic photosensitive member,
The process cartridge according to any one of claims 1 to 4, wherein a control of an operation of contacting / separating or canceling the pressure contact between the electrophotographic photosensitive member and the process means is performed. 6. An image forming apparatus comprising: at least an electrophotographic photosensitive member; a process unit acting on the electrophotographic photosensitive member; and a gear rotating integrally or synchronously with the electrophotographic photosensitive member. A thrust generating member meshing with the thrust generating member, a rotating member having an inertial force engaged with the thrust generating member, and a stopper member provided integrally with the rotating member and movable in the axial direction. Moving the stopper member from the first position to the second position, and when the rotation of the electrophotographic photoreceptor stops, the rotation member continues to rotate until it loses kinetic energy. The image forming apparatus is returned from the second position to the first position. 7. In the thrust generating member, a drag is generated at a contact portion with another drive transmitting portion when driving is transmitted, and the contact portion has a first tapered shape for directing the drag in a thrust direction. The first tapered shape is a shape in which the thrust generating member and the other drive transmission portion generate a thrust force in a direction in which the thrust generating member and the other drive transmitting portion are separated from each other or in a direction in which they are attracted to each other when the electrophotographic photosensitive member is rotated. The thrust force moves from the first position at the time of rotation stop to the second position, while when the electrophotographic photoreceptor stops, the rotation member continues to rotate until it loses kinetic energy, A reaction force is generated between the first tapered shape and a second tapered shape that generates a reverse thrust force, and the stopper member is returned to the first position. 7. The image forming apparatus according to claim 6, wherein: 8. The thrust generating member and the rotating member are connected by a twisted hole having a polygonal cross section and a twisted polygonal protrusion fitted therein, and the thrust generating member and the rotating member are rotated when the electrophotographic photosensitive member is rotated. The stopper member is rotated from a first position at the time of rotation stop to a second position by the rotation of the electrophotographic photosensitive member when the stopper member is rotated by an axial force generated at the fitting portion. When the stopper stops, the stopper member also stops, while the rotating member continues to rotate until it loses the energy of rotation, so that the axial force generated in the fitting portion is in the opposite direction to the rotation of the electrophotographic photosensitive member. 7. The image forming apparatus according to claim 6, wherein the stopper member is returned to the first position from the second position. 9. At least an electrophotographic photoreceptor, processing means acting on the electrophotographic photoreceptor, a helical gear rotating integrally or synchronously with the electrophotographic photoreceptor,
An image forming apparatus comprising: a helical gear with a stopper integrally formed with a helical gear that engages with the helical gear; and a rotating member having an inertial force. A thrust force is generated at the meshing portion of the helical gear, and the helical gear with the stopper moves from the first position at the time of rotation stop to the second position by the thrust force, while, when the electrophotographic photosensitive member stops, An image forming apparatus, wherein the rotating member continues to rotate until it loses kinetic energy, generates a thrust force in a direction opposite to the moving direction, and the helical gear with stopper is returned to a first position. 10. Using the fact that the stopper member is at a different position between a first position during stop of the electrophotographic photosensitive member and a second position during rotation of the electrophotographic photosensitive member, The image forming apparatus according to any one of claims 6 to 9, wherein the image forming apparatus controls an operation of contacting or separating an electrophotographic photosensitive member from the process means or an operation of releasing the pressure contact. 11. An assembly comprising at least an electrophotographic photosensitive member, processing means acting on the electrophotographic photosensitive member, and a gear rotating integrally or synchronously with the electrophotographic photosensitive member. A rotating member having an inertial force engaged with the thrust generating member, and a stopper member provided integrally with the rotating member and capable of moving in the axial direction; Sometimes, the stopper member is moved from the first position to the second position, and when the rotation of the electrophotographic photosensitive member stops, the rotation member continues to rotate until it loses kinetic energy. The assembly as claimed in claim 2, wherein said assembly is returned from said second position to said first position. 12. In the thrust generating member, a drag is generated at a contact portion with another drive transmitting portion when driving is transmitted, and the contact portion has a first tapered shape for directing the drag in a thrust direction. The first tapered shape is a shape in which the thrust generating member and the other drive transmission portion generate a thrust force in a direction in which the thrust generating member and the other drive transmitting portion are separated from each other or in a direction in which they are attracted to each other when the electrophotographic photosensitive member is rotated. The thrust force moves from the first position at the time of rotation stop to the second position, while when the electrophotographic photoreceptor stops, the rotation member continues to rotate until it loses kinetic energy, It is characterized in that a reaction force is generated between the first tapered shape and a second tapered shape that generates a reverse thrust force, and the stopper member is returned to the first position. The assembly of claim 11, wherein 13. The thrust generating member and the rotating member are coupled by a twisted hole having a polygonal cross section and a twisted polygonal protrusion fitted therein, and the thrust generating member and the rotating member are rotated when the electrophotographic photosensitive member rotates. The stopper member is rotated from a first position at the time of rotation stop to a second position by the rotation of the electrophotographic photosensitive member when the stopper member is rotated by an axial force generated at the fitting portion. When the stopper stops, the stopper member also stops, while the rotating member continues to rotate until it loses the energy of rotation, so that the axial force generated in the fitting portion is in the opposite direction to the rotation of the electrophotographic photosensitive member. And returning the stopper member from the second position to the first position.
Assembly. 14. An assembly comprising at least an electrophotographic photosensitive member, processing means acting on said electrophotographic photosensitive member, and a helical gear rotating integrally or synchronously with said electrophotographic photosensitive member. A helical gear with a stopper having an integral stopper member, and a rotating member having an inertial force, wherein the helical gear with a stopper generates a thrust force at a meshing portion with another helical gear when driven, The helical gear with the stopper moves from the first position at the time of rotation stop to the second position by the thrust force. On the other hand, when the electrophotographic photosensitive member stops, the helical gear rotates until the rotating member loses kinetic energy. To generate a thrust force in a direction opposite to the moving direction, and the helical gear with the stopper moves to the first position. The assembly according to claim is that the. 15. Using the fact that the stopper member is at a different position between a first position during stop of the electrophotographic photosensitive member and a second position during rotation of the electrophotographic photosensitive member, The assembly according to any one of claims 11 to 14, wherein an operation of contacting / separating or releasing pressure contact between the electrophotographic photosensitive member and the process means is controlled.