JP2001117467A - Process cartridge, image forming device and assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a process cartridge, etc., which can detach and attach a processing means from and to a photoreceptor without requiring reverse rotation of the photoreceptor by constituting a detaching and attaching mechanism without using an electrical part such as a solenoid. SOLUTION: A stopper driving gear 35b obtains rotary driving force by being engaged with a drum gear 39. The gear 35b and an energized rotating member 35c are brought into contact with each other on a projection and tapered surface and force in the direction of a thrust is generated at the gear 35b by resistance by rotation. A center distance between a tooth-locked gear 34 fitted to a charged roller metallic core 8a and the gear 39 is made to be longer than that at the time of pressing in contact with the drum 7 of a charging roller at the time of engaging each other. A stopper 35a provided at the gear 35b is slid in the direction of an arrow (a) by rotation of the gear 39 and stops the gear 34 by entering its rotating surface, and the roller 8 comes into the state of pressurized contact with the drum 7 by an energizing member. By the stop of the rotation of the gear 39 and rotating again of it, the part 35a is slid in a reverse direction and in a direction (a) and the gear 34 is rotated to be engaged with the gear 39 to separate the roller 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, an electrophotographic apparatus generally forms an image by the following image forming process.

An electrophotographic photosensitive member such as selenium, cadmium sulfide, zinc oxide, amorphous silicon, or an organic photoconductor, which is generally a rotating drum type image carrier, is used.
The photoreceptor surface is uniformly charged to a predetermined polarity and potential by a charging unit, the charged photoreceptor surface is exposed by an image exposing unit, and an electrostatic latent image corresponding to the exposed image is formed. A toner of a developer is attached to the electrostatic latent image and developed as a toner image, the toner image is transferred to a recording medium such as paper, and the transferred toner image is fixed to the recording medium by a fixing unit to form an image forming product. (Copies, prints) are discharged outside the machine. The photoreceptor after the transfer of the toner image is subjected to image formation repeatedly after the transfer residual toner is removed by a cleaning unit (cleaner).

In an assembly including a photoreceptor or a process cartridge in which these process means are detachable from a printer or a copying machine main body, the initial setting state is a process means disposed around the photoreceptor,
In particular, many members in which a member that comes into contact with a photoreceptor maintains the contact state are known and have been put to practical use. In order to prevent dents due to vibration or dropping, a protective member is interposed between the photoconductor and other contact members, and the contact 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.

[0005]

However, as a member that keeps in contact with a photosensitive member, particularly a photosensitive drum (drum-shaped photosensitive member) having an organic photosensitive layer, a cleaning member,
There are a contact charging member or a developing member, and if these are left and stored in a state where the process cartridge is not used, various problems described below may occur.

In a blade having an edge portion as a cleaning member, pressure is concentrated on the edge portion, and unevenness is generated on the surface layer of the photosensitive drum in contact with the edge portion. In some cases, a horizontal line was generated on the image regardless of the image formation.

When the cleaning member is a blade made of rubber or the like, the pressure contact force against the photosensitive drum is given by the displacement and deformation of the blade itself, so that the blade is permanently deformed and the pressure contact force is reduced. In some cases, cleaning failure such as residual toner may occur, and consequent image contamination may occur.

When the contact charging member is made up of a roller or a blade, the contact charging member itself undergoes compression deformation or permanent deformation due to its own pressure contact, and this causes loss of uniformity of charging, resulting in image defects.

[0009] Even in a contact type developing roller as a developing member, the contact nip portion of the developing roller is deformed by compression.
Due to defective coating of the toner or displacement of the pressure contact at the developing portion, unevenness may occur in the pitch of the pressure contact portion in the image.

Further, each of the above members is made of rubber, resin, or the like, and depending on the state of the surface being soiled or the additives contained therein, the deposition of the photosensitive agent on the photosensitive drum, the progress of impurities therein, Cracks of the drum were generated, and the photosensitive characteristics were partially reduced, the surface of the photosensitive film was contaminated, and significant image defects were sometimes caused.

In order to prevent such a problem, for example, there is known a method in which a sheet-like inclusion is inserted between a developing roller and a photosensitive drum, and the sheet-like inclusion is removed by hand at the time of use. There is a possibility that the user forgets to do so and puts it into the image forming apparatus as it is, which may cause damage to the process cartridge or damage and deformation of the apparatus main body.

Further, in a cartridge of a type in which each member is attached and detached in accordance with the attachment and detachment of the process cartridge, the contact of the process means can be released after the product is manufactured until the user starts using it. Yes, but no measures have been taken for long-term non-use after starting use.
The process means has to be selected from a material that does not easily deform, which makes it difficult to select a material.

A method of using a solenoid clutch or a method of rotating the photosensitive drum in a direction opposite to that during image formation in order to move the process means has a mechanism for bringing the process means into contact only during image formation. There is a process cartridge employed, which does not cause image formation failure due to the above-described leaving.

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 impairs the cleaning performance of the cleaning blade that is in contact with the photosensitive drum, and causes residual toner on the photosensitive drum to be damaged. There is a problem that cannot be removed. In general, the rotating unit of the developing device that supplies an appropriate amount of toner to the photosensitive drum is synchronized with the rotation of the photosensitive drum. When the rotating unit of the developing device rotates in the reverse direction, more toner than necessary is supplied. As a result, toner may spill out.

In order to prevent this, if a one-way clutch or the like is attached so that the photosensitive drum rotates only in the rotation direction at the time of image formation, the cost is increased.

An object of the present invention is to provide a separation / contact mechanism without using expensive electric parts such as a solenoid when separating / contacting the process means from / to the photosensitive member. An object of the present invention is to provide a process cartridge, an image forming apparatus, and an assembly capable of performing a separation / contact operation without requiring reverse rotation of the body.

[0017]

The above object is achieved by a process cartridge, an image forming apparatus and an assembly according to the present invention. In summary, the present invention comprises at least a rotatable electrophotographic photoreceptor, processing means for forming an image on the photoreceptor, and a gear rotating integrally or synchronously with the photoreceptor, In a process cartridge detachable from the image forming apparatus main body, at least one of a thrust force generating section, a rotating member having an inertial force, a stopper member movable in an axial direction, and an elastic member for pushing back the stopper member is provided. A stopper member for moving the stopper member from the first position to the second position when the photosensitive member is rotationally driven; and when the photosensitive member stops rotating, the rotating member moves. Rotation continues until energy is lost, thereby reducing the drag on the stopper member, and the force of the elastic member causes the stopper member to move from the second position to the second position. A process cartridge, wherein a is returned to the position.

Further, the present invention has at least an electrophotographic photosensitive member which is driven to rotate, a process means for forming an image on the photosensitive member, and a gear which rotates integrally or synchronously with the photosensitive member. The image forming apparatus includes at least one of a thrust force generating unit, a rotating member having an inertial force, a stopper member movable in an axial direction, and an elastic member for pushing back the stopper member. When the body receives the rotation drive, the stopper member is moved from the first position to the second position, and when the rotation of the photoconductor stops, the rotation member continues to rotate until the rotating member loses kinetic energy. Thereby, the drag on the stopper member is reduced, and the stopper member is returned from the second position to the first position by the force of the elastic member. An image forming apparatus.

Furthermore, the present invention has at least an electrophotographic photosensitive member which is driven to rotate, a process means for forming an image on the photosensitive member, and a gear which rotates integrally or synchronously with the photosensitive member. In the assembly, the photoconductor has at least one member of a thrust force generating portion, a rotating member having an inertial force, a stopper member movable in an axial direction, and an elastic member for pushing back the stopper member. When receiving the rotation drive, move the stopper member from the first position to the second position, when the rotation of the photoconductor stops, continue to rotate until the rotating member loses kinetic energy, Thereby, the drag on the stopper member is reduced, and the stopper member is returned from the second position to the first position by the force of the elastic member. It is a standing body.

According to the present invention, in the thrust generating portion, 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 tapered shape for directing the drag in the thrust direction. The tapered shape is a shape in which the thrust generating unit and the other drive transmitting unit generate a force in a direction in which the thrust generating unit and the other drive transmitting unit are separated from each other or in a direction in which the thrust generating unit is attracted to each other when the photoconductor rotates. From the position to the second position by the thrust force, the rotation member stops after a delay after the rotation of the photoconductor, reduces the drag of the thrust force generation unit, the stopper member is The elastic member returns from the second position to the first position. By utilizing the fact that the stopper member is at a different position during rotation and stoppage of the photoconductor, control of a separation operation or a pressure release operation between the photoconductor and the process means is performed. The process unit is a charging member that contacts the photoconductor and charges the photoconductor.

[0021]

Embodiments of the present invention will be described below in more detail with reference to the drawings.

Embodiment 1 This embodiment shows an image forming apparatus which is a laser beam printer.

First, an overall configuration of an electrophotographic image forming apparatus and a process cartridge of this embodiment is shown in FIGS.
This will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the overall configuration of an image forming apparatus in which a process cartridge is mounted, and FIG.
3 is a sectional view showing the process cartridge, FIG. 3 is a perspective view showing the process cartridge, and FIG. 4 is a sectional view showing a state in which the open / close cover of the apparatus main body is opened and the process cartridge is mounted on the apparatus main body.

(Overall Configuration) As shown in FIG. 1, an electrophotographic image forming apparatus A includes a process cartridge B having a photosensitive drum (drum type electrophotographic photosensitive member) 7 as an image carrier.
A toner image is formed on the photosensitive drum 7 by an electrophotographic process, and the recording medium 2 set on the paper feed tray 3a is synchronously formed on the photosensitive drum 7 with the pickup roller 3b and the transport roller 3c. By applying a voltage having a polarity opposite to the charging polarity of the toner to the transfer roller 4 on the side of the apparatus main body,
The toner image on the photosensitive drum 7 is transferred to the recording medium 2. Thereafter, the recording medium 2 to which the toner image has been transferred is conveyed to a fixing unit 5 by a guide 3d on the apparatus main body side. The fixing unit 5 includes a driving roller 5a and a fixing roller 5 having a built-in heater.
b, by applying heat and pressure to the recording medium 2 passing between them, the transferred toner image is fixed to the recording medium 2, and the fixed recording medium 2 is discharged to the discharge roller 3.
e, the sheet is inverted and conveyed at 3f, and is discharged to the discharge tray 6.

In the process cartridge B, first, the photosensitive drum 7 is rotated, and the surface thereof is uniformly charged by applying a voltage to a charging roller 8 which is a charging unit in contact with the surface. The photosensitive drum 7 is irradiated with a laser beam corresponding to image information from the optical system 1 through the exposure opening 9 to form an electrostatic latent image on the surface of the photosensitive drum 7. Develop using. The optical system 1 has a laser diode 1a, a polygon mirror 1b, and a reflection mirror 1d.

As shown in FIG. 2, the developing means 10 supplies the magnetic toner contained in the toner chamber 10a to the developing chamber 10b, and places the developing roller on a rotating developing roller 10c attached to the developing chamber 10b. The toner is carried by a fixed magnet (not shown) in 10c, and the toner is regulated by a developing blade 10d to apply a triboelectric charge, form a toner layer having a predetermined thickness, and transport the toner layer to a developing area facing the photosensitive drum 7. I do. Then, the toner is transferred to and adhered to the electrostatic latent image on the photosensitive drum 7 in the developing area, and is visualized as a toner image.

After the transfer of the toner image onto the recording medium 2 by the transfer roller 4, the photosensitive drum 7 is removed by scraping off the transfer residual toner on the surface thereof by a cleaning blade 11a made of an elastic member of the cleaning means 11. The removed toner is stored in the toner reservoir 11b.

The process cartridge B includes a developing frame 1
2. The developing frame member 13 and the cleaning frame 14 are combined to form a cartridge frame, and components such as the photosensitive drum 7 are housed in the frame. That is, the developing frame 12 and the developing wall member 13 are welded to each other to form the toner chamber 10.
a and a developing chamber 10b are formed, and a developing roller 10c and a developing blade 10d are attached to the developing chamber 10b. The cleaning frame 14 includes the photosensitive drum 7, the charging roller 8, and the components 11 of the cleaning unit 11.
a, 11b are attached. Then, the developing frame 12 and the cleaning frame 14 are swingably connected to each other,
A process cartridge B is configured.

The process cartridge B is provided with the above-described exposure opening 9 for irradiating the photosensitive drum 7 with a laser beam corresponding to image information, and the transfer opening 15, and the two openings 9, 15 are provided. A shutter member 16 which can be opened and closed is attached. The transfer opening 15 is for exposing the transfer roller 4 to the photosensitive drum 7 when transferring the toner image to the recording medium 2.

As shown in FIG. 4, an opening / closing cover 18 is attached to the apparatus main body 17 of the image forming apparatus A so as to be rotatable about a shaft 19. When the opening / closing cover 18 is opened, a guide member (formed of a rail groove) (not shown) for guiding the process cartridge B is provided inside the apparatus main body 17, and the operator moves the cartridge B along the guide member.
Can be attached and detached. At this time, as shown in FIG.
The protrusion 24 and the second protrusion 25 are guided along the guide member.

As shown in FIGS. 2 and 3, the shutter member 16 includes a first shutter portion 16a and an arm portion 16d fixed to a rotatable support 16c.
And a second shutter 16d supported by the torsion coil spring 23 mounted on the rotary support 16c.
When the shutter 16a closes the exposure opening 9 and the second shutter 16b closes the transfer opening 15, and when the process cartridge B is outside the apparatus main body 17, the first shutter 16a and the second shutter 16b are closed. Shutter section 16
b closes the exposure opening 9 and the transfer opening 15, respectively.

When the process cartridge B is mounted on the apparatus main body 17 with the gripping member 26 provided integrally with the cleaning frame 14, the tip of the arm 16d supporting the second shutter 16b covering the photosensitive drum 7 is provided. In a state where the locking member 16e projecting outward in the longitudinal direction of the cartridge B hits the apparatus main body 17 and the further entry into the cartridge mounting portion is stopped, the cartridge B is moved to the first and second protrusions 24 and 25.
Moves forward along the guide member of the apparatus main body 17, and the shutter member 16, as shown in FIG.
The transfer opening 15 is released. Cartridge B
The torsion coil spring 23
The shutter member 16 closes the exposure opening 9 and the transfer opening 15 by the spring force of.

(Charging Roller) The charging roller 8 will be described. As shown in FIG. 5, the charging roller 8 has a structure in which a core metal (conductive base) 8a made of SUS is surrounded by a resistance layer 8b. The resistance layer 8b has a coating layer 8 as a surface layer.
c and a lower elastic layer 8d. 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 member, thereby forming an electric circuit. A charging bias is supplied from a power source (not shown) to the charging roller 8 via the bearing 20.
The photosensitive drum 7 is charged via the nip 22 with the photosensitive drum 7. The surface of the photosensitive drum 7 is uniformly charged as it moves in the L direction.

According to the present invention, by constructing a special stopper means, the separation / contact mechanism is constituted without using an electric part such as a solenoid, and a process means such as a charging roller is provided on a photosensitive drum, and a photosensitive drum is provided on a reverse side. The separation / contact operation can be performed without rotating.

First, the stopper means constructed in the present invention will be described. FIG. 6 is an exploded view showing the stopper means according to the present invention. The part moving the stopper 35a and the bearing guide 31 are shown.

The stopper driving gear 35b is a drum gear 3
9 (see FIG. 13) to obtain a rotational driving force. The stopper portion 35a and the stopper drive gear 35b are integral parts. The stopper driving gear 35b and the rotating member 35c both rotate while being supported by a fixed shaft (not shown). The stopper driving gear 35b and the rotator 35c transmit power by a method of generating a thrust force by an effect generated at a contact portion of each other. As one example, one or more cylindrical projections 35c1 are attached to the rotating member 35c. The side surface 35b1 of the stopper drive gear 35b that comes into contact with the projection 35c1 has a tapered shape. At this time, in order to generate a drag at the tapered portion, there must be a load on the side to which power can be transmitted. Therefore, the load is applied by urging the friction member 37 with the compression coil spring 38.

A series of operations of the stopper member 35 will be described with reference to FIGS. FIG. 7A shows a state in which the photosensitive drum is stopped. As shown in FIG. 7B, when the stopper driving gear 35b rotates, a drag is generated by pressing the protrusion 35c1 with the tapered surface 35b1, and the stopper portion 35a is moved in the direction of the arrow a by the force of the axial component of the drag. Slide until it hits.

When the rotation of the drum gear 39 stops, the stopper driving gear 35b also stops (FIG. 8).
(A)). The rotation member 35c stops after rotating until it reaches the state shown in FIG. 7A or until there is no inertial force. Due to the rotation due to the inertial force, the drag of the projection disappears. As the force in the direction a disappears, FIG.
As shown in (b), the stopper 35a is slid in the direction of b when receiving the force of the compression coil spring 41 in the direction of arrow b.

The thrust force applied to the stopper member will be described with reference to FIG. In FIG. 9, a stopper member S1 that slides and a tapered portion T1 of a rotating member are provided.
If there is no drag at the contact portion, no axial force P acts on the stopper. When there is drag, it means that there is a load on the side receiving the force. When there is a load, it becomes difficult to rotate the photosensitive drum due to inertial force after the rotation of the photosensitive drum has stopped. When the amount of rotation due to the inertial force is small, the amount of return (stroke) of the stopper decreases.

The relationship between the axial force and the rotation due to the inertial force will be described. As shown in FIG. 9, when the force received in the circumferential direction (rotational direction) at the contact portion of the tapered portion T1 is F1, the axial force P converted by the tapered portion is F1.
Is the friction coefficient at the contact portion, and P = N sin θ−μN cos θ, F 1 = N cos θ +
μN sin θ ∴P = F1 × (tan θ−μ) / (1 + μ tan θ)

Next, assuming that the radius of the rotating member 35c is R, the mass is M, and the number of rotations is ω, the rotational energy W of the rotating member 35c is I = 1/2 ×
Using R ² M, W = １ ／ × Iω ² .

The amount that can be rotated before this rotational energy is consumed by the above-described F1 is the amount of rotation due to inertial force. It is necessary to accumulate rotational energy for the required stroke. According to this principle, the stopper portion 35a slides in the direction of arrow a while the drum gear 39 is continuously rotating, and returns to the original position by sliding in the direction of b when stopped.

As shown in FIG. 10, both the rotating member 35c and the stopper driving gear 35b have tapered shapes 35c.
The same movement can be made even if 2, 35b1 is added.

FIG. 11 is a perspective view showing an example in which the thrust force generated at the time of rotational driving is tapered so that the components generating the drag attract each other.
Shows a side view.

FIG. 11 shows a state before the components are assembled. FIG. 12 (a) shows a state of being assembled along the center line. FIG. 12B shows a state where the stopper 35a is moved by the thrust force when receiving the rotation drive. The principle of the operation is that the direction of the thrust force generated in the tapered portion is opposite to that of the aforementioned mechanism.

According to the present invention, a separating mechanism for the process means is constituted by using the stopper means having a different position of the stopper portion 35a when the photosensitive drum 7 is rotating and stopped.

In the first embodiment, a description will be given of a method of separating the processing means by using the toothless gear. Here, a charging roller will be described as an example of the process means.

FIG. 13 is a diagram showing the vicinity of the control unit of the separation / contact mechanism of the process means of the process cartridge B of this embodiment.

The inter-axis distance when the missing tooth gear 34 meshes with the drum gear 39 is arranged to be larger than the inter-axis distance when the charging roller 8 is pressed against the photosensitive drum 7. FIG. 13 shows a state where the toothless gear 34 meshes with the drum gear 39 and 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 photosensitive drum 7 and the stopper driving gear 35b meshing with the drum gear 39 rotate. Further, the charging roller 8 and its core metal 8a are rotated by the rotation of the photosensitive drum 7 or by another driving source. The toothless gear 34 fitted with the core bar 8a receives a frictional force from the core bar 8a, and uses the frictional force as a drive source.

FIG. 14 shows a state during image formation.
When the drum gear 39 is rotating, the stopper 3
5a slides in the direction of “a” in the figure and enters the rotation plane of the missing tooth gear 34 to stop the rotation of the missing tooth 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, the charging roller 8 and the photosensitive drum 7
Since there is no member for regulating the distance between the shafts, the charging roller 8 is brought into pressure contact with the photosensitive drum 7 by the force of the urging member 21 shown in FIG. Image formation is performed in this state.

The sequence of the operation for separating the charging roller 8 will be described. In the separating operation, the rotation of the drum gear 39 is temporarily stopped after the image formation, and then the drum gear 3 is again rotated.
This is completed by rotating 9 by a fixed angle.

FIG. 15 shows a drum gear 39 after completion of image formation.
Represents the state immediately after stopping. First, when the rotation of the drum gear 39 is stopped, the stopper 35a slides in the direction of the arrow b in the figure. In this state, the rotation of the toothless gear 34 is restricted. However, the missing tooth gear 34 is 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. 16 shows a state in which the drum gear 39 is once again rotated in order to separate the charging roller 8. At this time, the stopper 35a is again connected to the missing tooth gear 3
4, the toothless gear 34 starts rotating at the same time as the rotation of the drum gear 39, so that the rotation of the toothless gear 34 cannot be stopped. When the toothless gear 34 rotates and meshes with the drum gear 39, and the drum gear 39 is rotated by an angle that comes to a position where the charging roller 8 is completely separated, the drum gear 39 is stopped.

When stopped, the charging roller 8 shown in FIG. 13 returns to the separated state.

Embodiment 2 FIG. 17 is a view showing the periphery of a charging roller separation / contact mechanism of a process cartridge B according to another embodiment of the present invention.
In this embodiment, the input gear 42 is coaxial with the photosensitive drum 7.
a, a spring clutch including a control unit 42b and a cam 42c is provided.

FIG. 17 shows a state in which the charging roller 8 is separated from the photosensitive drum 7. Spring clutch 4
The second input gear 42 a is fixed to the shaft of the photosensitive drum 7. The output portion of the spring clutch has a cam shape. The cam 42c is used to push up the charging roller core 8a and separate it from the photosensitive drum 7.

FIG. 18 shows a state in which an image is formed and a cam 42c is formed.
Stops at a position where it does not contact the charging roller core 8a. When the drive transmission of the spring clutch is being performed,
The input gear 42a, the spring clutch controller 42b, and the cam 42c rotate simultaneously. When the rotation starts, the stopper portion 35a slides in the direction of a. A projection 42b1 is attached to the spring clutch control section 42b, and when the stopper 42a hits the projection 42b1 to stop the rotation, the drive transmission of the spring clutch 42 is cut off and the rotation of the cam 42c stops immediately.

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, the stopper portion 35a
Is in a position where it slides in the direction of a and abuts. At this position, the rotation of the projection of the spring clutch control section 42b is stopped. Since the stop position of the cam 42c is determined by the phase with the projection, it always stops at the same position.

FIG. 19 shows a state immediately after the rotation is temporarily stopped after the image formation. At this time, as in the first embodiment,
The stopper portion 35a slides in the direction b by the force of the compression coil spring 41. As a result, the projection 42 of the clutch
There is nothing that regulates the rotation of b1.

FIG. 20 shows that the input gear 42a is rotated again,
A state where the cam 42c is being rotated is shown. Since the position where the cam 42c is stopped can be calculated from the phase with the projection of the spring clutch, the rotation amount at this time is the amount by which the cam comes to a position where the charging roller 8 can be separated from the photosensitive drum 7. . If the rotation of the input gear 42a is stopped at this position, the separated state is maintained (return to the state of FIG. 17).

Embodiment 3 FIG. 21 is a sectional view showing a process cartridge according to still another embodiment of the present invention.

In the present embodiment, as shown in FIG. 21, the separating / contacting mechanism using the stopper means of the stopper 35 and the toothless gear 34 is used as the charging roller 8, the developing roller 10c and the transfer roller 4 of the process cartridge B. Attached to each.

Each of the process means such as the charging roller 8 and the like is the same as in the first embodiment.
When the missing tooth gear 34 is engaged with the process means, the respective process means are separated from the photosensitive drum 7 as shown in FIG.

In the above, the image forming apparatus has been described as a cartridge type apparatus in which a process cartridge incorporating each process means such as a photosensitive drum and a charging roller is detachably installed in the apparatus main body. The present invention is not limited to this, and may be an ordinary type device in which the photosensitive drum and each process means are fixedly installed. Also, an image forming apparatus using a photosensitive drum as a photosensitive member has been described.
The present invention can be applied to an image forming apparatus using a photosensitive belt which is a belt-shaped photosensitive member.

[0066]

As described above, according to the present invention,
A process cartridge, an image forming apparatus, and an assembly including at least a rotatably driven electrophotographic photosensitive member, a process unit for forming an image on the photosensitive member, and a gear that rotates integrally or synchronously with the photosensitive member; The photosensitive member receives at least one of a thrust force generating portion, a rotating member having an inertial force, a stopper member movable in an axial direction, and an elastic member for pressing back the stopper member. When, the stopper member is moved from the first position to the second position, and when the rotation of the photoconductor stops, the rotation member continues to rotate until it loses kinetic energy,
This reduces the drag on the stopper member,
Since the stopper member is returned from the second position to the first position by the force of the elastic member, the mechanism for separating and connecting the process means to and from the photoreceptor is configured without using expensive electric components such as solenoids. The separation / contact operation can be performed without cost and without requiring reverse rotation of the photoconductor.

[Brief description of the drawings]

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

FIG. 2 is a vertical sectional view of a process cartridge.

FIG. 3 is a perspective view of a process cartridge.

FIG. 4 is a longitudinal sectional view showing a state in which an opening / closing cover of the image forming apparatus of FIG. 1 is opened and a process cartridge is mounted.

FIG. 5 is an explanatory diagram illustrating a charging roller of the process cartridge.

FIG. 6 is a layout view showing components constituting stopper means according to the present invention.

FIG. 7 is an explanatory diagram showing the operation of the stopper means.

FIG. 8 is an explanatory diagram showing the operation of the stopper means.

FIG. 9 is an explanatory diagram showing a thrust force generated in a stopper.

FIG. 10 is an explanatory view showing a modification of the stopper means.

FIG. 11 is an explanatory view showing still another modified example of the stopper means.

FIG. 12 is a sectional view of the stopper means of FIG. 11;

FIG. 13 is an explanatory diagram showing a separation / contact mechanism constructed using the stopper means of the present invention.

FIG. 14 is an explanatory diagram illustrating the operation of the separation / contact mechanism of FIG. 13;

FIG. 15 is an explanatory diagram showing the operation of the separating mechanism.

FIG. 16 is an explanatory view showing the operation of the separation / contact mechanism.

FIG. 17 is an explanatory view showing another example of the separation / contact mechanism constructed using the stopper means of the present invention.

FIG. 18 is an explanatory view showing the operation of the separating mechanism in FIG. 17;

FIG. 19 is an explanatory diagram illustrating the operation of the separation / contact mechanism.

FIG. 20 is an explanatory view showing the operation of the separating mechanism.

FIG. 21 is an explanatory diagram showing another example of the process cartridge of the present invention.

FIG. 22 is an explanatory view showing a state where the process means in the cartridge of FIG. 21 is separated.

[Explanation of symbols]

 Reference Signs List 7 photosensitive drum 8 charging roller 34 missing tooth gear 35a stopper portion 35b stopper driving gear 35c rotating member 37 friction generating member 38 compression coil spring 39 drum gear 41 compression coil spring

Claims (12)

[Claims] 1. An image forming apparatus comprising at least a rotatable electrophotographic photoreceptor, a process means for forming an image on the photoreceptor, and a gear rotating integrally or synchronously with the photoreceptor. A process cartridge detachable from the main body, comprising at least one member of a thrust force generating portion, a rotating member having an inertial force, a stopper member movable in an axial direction, and an elastic member for pushing back the stopper member. Then, when the photoconductor receives rotational driving, the stopper member is moved from the first position to the second position, and when the rotation of the photoconductor stops, the rotating member loses kinetic energy. Until the stopper member is moved from the second position to the first position by the force of the elastic member. A process cartridge characterized in that it is returned. 2. In the thrust generating portion, 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 tapered shape for directing the drag in a thrust direction. The shape is such that the thrust generating unit and the other drive transmitting unit are separated from each other when the photoconductor rotates,
Alternatively, the stopper member moves from the first position at the time of rotation stop to the second position by the thrust force, and the rotation member stops rotating the photoconductor, in a shape that generates a force in a direction of attracting each other. Later, stop late,
The process cartridge according to claim 1, wherein a drag of the thrust force generating portion is reduced, and the stopper member is returned from the second position to the first position by a force of the elastic member. 3. The method according to claim 1, wherein the stopper member is located at a different position during rotation and at a stop of the photosensitive member, and controls a separating operation or a pressing release operation between the photosensitive member and a process unit. 1 or 2 process cartridges. 4. The process cartridge according to claim 1, wherein said process means is a charging member which contacts said photoconductor and charges said photoconductor. 5. An image forming apparatus comprising at least a rotatable electrophotographic photoreceptor, a process unit for forming an image on the photoreceptor, and a gear rotating integrally or synchronously with the photoreceptor. A thrust force generator, a rotating member having an inertial force, a stopper member movable in an axial direction, and an elastic member for pushing back the stopper member, wherein the photosensitive member is driven to rotate. When receiving, the stopper member is moved from the first position to the second position, and when the rotation of the photoconductor stops, the rotation member continues to rotate until it loses kinetic energy, thereby An image forming apparatus, wherein a resistance to a stopper member is reduced, and the stopper member is returned from a second position to a first position by a force of the elastic member. 6. The thrust generating portion generates a drag at a contact portion with another drive transmitting portion at the time of driving transmission, and the contact portion has a tapered shape for directing the drag in a thrust direction. The shape is such that the thrust generating unit and the other drive transmitting unit are separated from each other when the photoconductor rotates,
Alternatively, the stopper member moves from the first position at the time of rotation stop to the second position by the thrust force, and the rotation member stops rotating the photoconductor, in a shape that generates a force in a direction of attracting each other. Later, stop late,
The image forming apparatus according to claim 5, wherein a drag of the thrust force generator is reduced, and the stopper member is returned from the second position to the first position by a force of the elastic member. 7. A method for controlling a separation operation or a pressure release operation between said photosensitive member and a process means by utilizing the fact that said stopper member is at a different position during rotation and stoppage of said photosensitive member. 5 or 6. 8. The image forming apparatus according to claim 5, wherein said process means is a charging member which contacts said photosensitive member and charges said photosensitive member. 9. An assembly having at least a rotatable electrophotographic photoreceptor, processing means for forming an image on the photoreceptor, and a gear rotating integrally or synchronously with the photoreceptor, A thrust force generator, a rotating member having an inertial force, a stopper member movable in an axial direction, and at least one elastic member for pushing back the stopper member, wherein the photoconductor is driven to rotate. When receiving, the stopper member is moved from the first position to the second position, and when the rotation of the photoconductor stops, the rotation member continues to rotate until the rotating member loses kinetic energy, whereby the stopper An assembly for reducing drag on a member, wherein the force of the resilient member returns the stopper member from the second position to the first position. 10. The thrust generating portion generates a drag at a contact portion with another drive transmitting portion at the time of driving transmission, and the contact portion has a tapered shape for directing the drag in a thrust direction. The shape is such that the thrust generating portion and the other drive transmitting portion generate a force in a direction in which the thrust generating portion and the other drive transmitting portion are separated from each other when rotating the photoconductor, or in a direction in which they are attracted to each other. Moved to the second position by the thrust force, the rotation member stops after a delay after the rotation of the photoconductor, reduces the drag of the thrust force generation unit, the stopper member is the elastic member 10. The assembly of claim 9 wherein the force causes the second position to return to the first position. 11. A method for controlling a separation operation or a pressure release operation between the photosensitive member and a process means by utilizing that the stopper member is at a different position during rotation and stop of the photosensitive member. 9 or 10 assembly. 12. The assembly according to claim 9, wherein said process means is a charging member which contacts said photoconductor and charges said photoconductor.