JP2001134029A - Electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic image forming device where a strong connection between coupling members can be released when a processing cartridge is detached. SOLUTION: In the device, the release of the connection between a main body coupling member 2 and a cartridge coupling member 1 that are connected by engagement of a polygonal twisted hole 2-2 of the main body coupling member 2 and the projection 1-2 of a twisted prism of the cartridge coupling member 1 is carried out by driving a driving source in a direction opposite to a carrying direction of a recording medium by a carrying means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrophotographic image forming apparatus.

Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser printer, an LED printer, and the like), a facsimile machine, a word processor, and the like.

A process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member are integrally formed as a cartridge, and this cartridge is made detachable from an image forming apparatus main body. In addition, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are integrally formed into a cartridge so that the cartridge can be attached to and detached from the image forming apparatus main body. Furthermore,
This means that at least the developing means and the electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from the image forming apparatus main body.

[0004]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus using an electrophotographic image forming process, a cartridge is integrally formed with an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member, and the cartridge is used for image forming. A process cartridge system that can be attached to and detached from the forming apparatus main body is employed. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without relying on a serviceman, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.

In such an electrophotographic image forming apparatus, a cartridge coupling member is provided on a process cartridge side, and a main body coupling member is provided on a main body of the electrophotographic image forming apparatus. When mounted, the cartridge coupling member and the main body coupling member are connected. Then, the cartridge coupling member and the main body coupling member are firmly connected by rotating the main body coupling member by a drive motor provided on the main body side of the electrophotographic image forming apparatus. For this reason, when removing the process cartridge from the main body of the electrophotographic image forming apparatus, it is necessary to release the strong connection between the two coupling members.

[0006]

SUMMARY OF THE INVENTION The present invention is a further development of the above-mentioned prior art, and its main purpose is to release the firm connection of the coupling member when removing the process cartridge. An object of the present invention is to provide an electrophotographic image forming apparatus.

[0007]

A typical configuration of an electrophotographic image forming apparatus according to the present invention for achieving the above object is a process in which a process cartridge is detachable from a main body of the electrophotographic image forming apparatus and a recording medium is provided. An electrophotographic image forming apparatus for forming an image on a rotatable main body coupling member having (a) a polygonal twisted hole;
(B) an electrophotographic photosensitive member, a process means acting on the electrophotographic photosensitive member, and a twist provided integrally with the electrophotographic photosensitive member and fitted into a polygonal twisted hole of the main body coupling member. Mounting means for detachably mounting a process cartridge having a cartridge coupling member having a polygonal prism projection, (c) a drive source capable of forward and reverse rotation drive, and (d) driven by the drive source. (E) driving force transmitting means for transmitting a driving force for rotating the electrophotographic photosensitive member to the main body coupling;
Conveying means for conveying the recording medium, wherein the polygonal twisted hole of the main body coupling member and the twisted polygonal column projection of the cartridge coupling member are fitted and connected. An electrophotographic image forming apparatus, characterized in that the coupling between the coupling member and the cartridge coupling member is released by driving the driving source in a direction opposite to a direction in which the recording medium is conveyed by the conveying means. .

(Operation) In the above-described electrophotographic image forming apparatus, the driving source is driven in a direction opposite to the direction in which the recording medium is conveyed by the conveying means. Thereby, the rigid connection between the main body coupling member and the cartridge coupling member, in which the polygonal twisted hole of the main body coupling member and the projection of the twisted polygonal prism of the cartridge coupling member are fitted and connected, is provided. Can be canceled.

[0009]

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

[First Embodiment] A process cartridge and an electrophotographic image forming apparatus to which the process cartridge can be attached and detached will be specifically described with reference to FIG. FIG. 1 is a cross-sectional view of an electrophotographic image forming apparatus (laser beam printer) equipped with a process cartridge.

Here, as the order of the description, first, the overall configuration of the process cartridge and the electrophotographic image forming apparatus using the same will be described, and then the configuration of the coupling mechanism for driving the electrophotographic photosensitive member will be described.

(Overall Configuration) As shown in FIG. 1, this electrophotographic image forming apparatus (laser beam printer) A-1 has a drum shape having laser light corresponding to image information from an optical unit 21 in a process cartridge 10. An image is formed by an electrophotographic image forming process in which an electrostatic latent image is formed by irradiating an electrophotographic photosensitive member (hereinafter referred to as a “photosensitive drum”) 1-1 and then developed to form a toner (developer) image. Is what you do.

In synchronization with the formation of the toner image, a recording medium (recording paper, OHP sheet, cloth, etc.) 2 is conveyed from a feeding tray 23 by a conveying means 9 comprising a feeding roller 9a, a conveying roller 9b and the like. . Next, the toner image formed on the photosensitive drum 1-1 is transferred to the recording medium 22 by applying a voltage to a transfer roller 24 as a transfer unit. Next, the recording medium 22 to which the toner image has been transferred from the photosensitive drum 1-1 is guided by the guide plate 9c and is conveyed to the fixing device 7 as fixing means. The fixing device 7 includes a fixing rotator 7a having a built-in heater, and a pressure roller 7b that presses and conveys the recording medium 22 to the fixing rotator 7a.
The transfer toner image is fixed to the recording medium 22 by applying heat and pressure to the recording medium 22. The recording medium 22 is conveyed by the discharge roller pair 9d and discharged to the discharge tray 25.

On the other hand, the process cartridge 10
It has an electrophotographic photosensitive member and at least one process means. Here, as the process means, for example, a charging means for charging an electrophotographic photosensitive member, a developing means for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and a cleaning means for cleaning toner remaining on the surface of the electrophotographic photosensitive member There are cleaning means and the like. As shown in FIG. 1, the process cartridge 10 of the present embodiment
6. The developing means 27 and the cleaning means 28 are integrally provided with the photosensitive drum 1-1.

And a photosensitive drum 1-1 having a photosensitive layer.
And the surface thereof is uniformly charged by applying a voltage to a charging roller 26 serving as a charging unit, and a laser beam corresponding to image information from the optical unit 1 is exposed through an exposure opening 29 to the photosensitive drum 1-1. To form an electrostatic latent image, and the electrostatic latent image is developed by developing means 27.

The developing means 27 sends out the toner in the toner accommodating portion 27a to a developing chamber, rotates a developing roller 27b provided with a fixed magnet provided in the developing chamber, and frictionally charges the toner by a developing blade (not shown). The charged toner layer is formed on the surface of the developing roller 27b. Then, the toner is supplied to a developing area of the photosensitive drum 1-1, and the electrostatic latent image is developed to form a toner image.

After the toner image is transferred to the recording medium 22 by applying a voltage having a polarity opposite to that of the toner image to the transfer roller 24, the toner image remains on the photosensitive drum 1-1 by an elastic cleaning blade (not shown). Scraping off the toner,
Cleaning means 28 collecting in removed toner storage section 28a
Thus, the residual toner on the photosensitive drum 1-1 is removed.

The process cartridge 10 of this embodiment is
The photosensitive drum 1-1 and the charging roller 2 are mounted on a cartridge frame 10a constituting a housing of the process cartridge 10.
6. A cartridge mounting means (not shown) which is formed into a cartridge by supporting each member such as the developing roller 27b, the developing blade, and the elastic cleaning blade, and which is provided in an electrophotographic image forming apparatus main body (hereinafter referred to as "apparatus main body") 30 It is detachably attached to.

In this cartridge mounting means, as shown in FIG. 1, when the opening / closing cover 11 as the main body opening / closing member is opened in the direction of the arrow O about the shaft 11a, a space for the cartridge mounting portion appears. In the present embodiment, the discharge tray 25 is integrally attached to the opening / closing cover 11, and the optical unit 1 is integrally attached to the discharge tray 25. Then, the open / close cover 11 is moved together with the discharge tray 25 and the optical unit 1 by the arrow O.
It is configured so that the space of the cartridge mounting portion appears by opening in the direction. A cartridge mounting guide member (not shown) is disposed on the left and right sides of the space of the cartridge mounting section. Then, a guide (not shown) of the process cartridge 10 composed of a boss and a rib is fitted into the mounting guide member and guided, thereby forming the process cartridge 1.
0 is attached to and detached from the apparatus main body 30 in the arrow X direction.

(Configuration of Coupling Mechanism) Next, the configuration of the coupling mechanism will be described with reference to FIGS. FIG. 2 is a perspective view of the main body coupling member and the cartridge coupling member before connection.

In FIG. 1, reference numeral 2-1 denotes a large drum driving gear, reference numeral 3 denotes a stepping motor (hereinafter referred to as "motor") as a driving source capable of forward and reverse rotation driving, and reference numeral 3a is fixed to a rotating shaft 3b of the motor 3. A drive gear, 4 is a photosensitive drum drive system reduction gear, 5 is a fixing drive system reduction gear a, 6 is a fixing drive system transmission gear b, 7c is a pressure roller drive gear, 8 is a feed roller drive gear, and 12 is an opening / closing cover. 11 is a door switch as a detecting unit for detecting opening and closing of the door 11. Each of these members is disposed on the apparatus main body 30 side. The pressure roller drive gear 7c is attached to the pressure roller 7b of the fixing device 7, and the feed roller drive gear 8 is attached to the feed roller 9a. I have. Power is supplied to the motor 3 from a power supply device (not shown) provided in the apparatus main body 30.

The drive gear 3a meshes with the photosensitive drum drive system reduction gear 4 and the fixing drive system reduction gear a5. The large drum drive gear 2-1 meshes with the photosensitive drum drive system reduction gear 4 and the feed roller drive gear 8. The fixing drive system transmission gear b6 meshes with the fixing drive system reduction gear a5 and the pressure roller drive gear 7c. The drive gear 3a, the photosensitive drum drive system reduction gear 4, and the large drum drive gear 2-1 are rotationally driven by a rotation shaft 3b of a motor 3 to provide a driving force for rotationally driving the photosensitive drum 1-1. A drum drive gear train GL <b> 1 as drive force transmitting means for transmitting to the ring female side member (body coupling member) 2 is configured. Further, the drive gear 3a, the photosensitive drum drive system reduction gear 4, and the large drum drive gear 2-1.
The feed roller driving gear 8 is driven by the rotation shaft 3b of the motor 3 to transmit a driving force for rotationally driving the feed roller 9a to the conveying means 9 as a feeding roller as a conveying driving force transmitting means. The drive gear train GL2 is configured.
The driving gear 3a, the fixing driving system reduction gear a5, the fixing driving system transmission gear b6, and the pressure roller driving gear 7c
The fixing device 7 is driven to rotate by the rotation shaft 3 b of the motor 3.
And a pressure roller drive gear train GL3 as a fixing driving force transmitting means for transmitting a driving force for rotationally driving the pressure roller 7b.

In FIG. 2, reference numeral 1 denotes a photosensitive drum 1-.
1 is a coupling male side member as a cartridge coupling member connected to a longitudinal side end portion of the coupling male side member 1-2, and is a twisted polygonal column provided at a side end of the coupling male side member 1 (this embodiment). The boss 1-2 is a projection of a triangular prism in the example. 2 is a coupling female side member as a main body coupling member provided in the apparatus main body 30;
Reference numeral -1 denotes a drum driving large gear which has already been described, and 2-2 denotes a polygonal (triangular in the present embodiment) cross-section in which the coupling male side member 1 is fitted with the twisted polygonal column boss 1-2. Hole.

The coupling female member 2 is formed integrally with the large drum drive gear 2-1. The process cartridge 10 is linked with the opening and closing operation of the opening and closing cover 11 by an interlocking mechanism (not shown) provided in the apparatus main body 30.
Is moved in the longitudinal direction (axial direction) of the photosensitive drum 1-1 at the regular mounting position, so that the hole 2-2 is fitted to the boss 1-2 or the hole 2-2 is Boss 2-1
It is designed to withdraw from. The coupling male side member 1 is firmly connected to the photosensitive drum 1-1 by caulking connection. The twisting direction of the boss 1-2 and the hole 2-2 is such that when the photosensitive drum 1-1 and the large drum driving gear 2-1 rotate in the recording medium transport direction, they are attracted to each other and maintain a strong connection. It is molded into.

As described above, in the electrophotographic image forming apparatus A-1 of this embodiment, the interface between the process cartridge 10 and the process cartridge 10 is configured as described above, so that the process cartridge 10 can be attached to and detached from the apparatus main body 30. While making it possible, the miniaturization of the drive gear and the shift of the meshing frequency to the higher frequency side are realized. As a result, the occurrence of stripe-shaped image unevenness due to a large-sized drive gear and a meshing period is suppressed.

The door switch 12, as shown in FIG.
It is connected to a drive motor drive control unit 31 as drive source drive control means for controlling the drive of the motor 3. When it detects that the open / close cover 11 is closed, it outputs a close detection signal to the motor drive control unit 31, and when it detects that the open / close cover 11 is opened, it outputs an open detection signal to the motor drive control unit 31. I do. The motor drive control unit 31 includes a CPU and the like,
When a close detection signal is input and an image formation start signal is input from a control unit (not shown) for controlling the entire electrophotographic image forming apparatus, a forward drive signal is output to the motor 3 and the door switch 12 is opened. When a detection signal is input, a reverse rotation drive signal is output to the motor 3.

Next, the driving operation of the electrophotographic image forming apparatus according to the embodiment will be described with reference to FIGS. 1, 2 and 7. FIG.

As shown in FIG. 1, when the process cartridge 10 is mounted at the proper mounting position of the apparatus main body 30 and the opening / closing cover 11 is closed, the twisted hole 2-2 of the coupling female side member 2 shown in FIG. The coupling female side member 2 and the coupling male side member 1 are connected by fitting the twisted polygonal column boss 1-2 of the coupling male side member 1 with the coupling male side member 1. The door switch 12 is used to open and close the cover 1.
When the motor 1 is closed, the motor 3 is pre-rotated in the recording medium conveying direction before the recording medium is conveyed. Here, the pre-rotation means that in response to the input of the image formation start signal, the motor 3 is restarted to drive the photosensitive drum 1-1 to rotate again,
This means that the image forming apparatus A-1 executes a predetermined pre-image forming operation for a while. By this pre-rotation operation,
The motor 3 is driven to rotate forward, and the rotating shaft 3b is driven by a driving gear 3a.
Is rotated in the recording medium conveyance direction (clockwise direction), so that the photosensitive drum 1-1 in the process cartridge 10 and the twisted polygonal column boss 1 of the coupling male side member 1 are rotated.
-2 is firmly coupled to the twisted hole 2-2 of the coupling female member 2, which is the main body side interface. The driving force of the motor 3 is transmitted via the photosensitive drum driving system reduction gear 4 to the large drum driving gear 2-1 of the coupling female member 2.
To the hole 2 of the coupling female member 2
-2, and is transmitted to the boss 1-2 of the coupling male member 1 to rotate the photosensitive drum 1-1. Also,
The driving force of the motor 3 is transmitted via a photosensitive drum driving system reduction gear 4 to a large drum driving gear 2-
1 and further transmitted to a feed roller driving gear 8 for driving the feeding / conveyance of the recording medium 22,
Is driven to rotate. Thereby, the recording medium 22 is conveyed from the feeding tray 23 into the apparatus main body 30 by the feeding roller 9. Further, the driving force of the motor 3 is transmitted to the fixing device 7 via the fixing drive system reduction gear a5, the fixing drive system transmission gear b6, and the pressure roller drive gear 7c, and rotationally drives the pressure roller 7b of the fixing device 7. Let it.

In this state, when the user opens the opening / closing cover 11 to remove the process cartridge 10 from the apparatus main body 30, this is detected by the door switch 12, and the motor drive control unit 31 causes the motor 3 to operate.
For a certain period of time so as to rotate in the direction opposite to the direction of rotation when the recording medium is fed. This allows motor 3
Is driven in reverse, and the rotating shaft 3b rotates the drive gear a in the direction opposite to the recording medium conveyance direction (counterclockwise direction).
As a result, the drum driving large gear 2-1 of the coupling female side member 2 also rotates in the direction opposite to the recording medium transport direction, and the hole 2-2 of the coupling female side member 2 also rotates in the opposite direction to the recording medium transport direction. Is applied.

Here, the twisted polygonal hole 2-2 of the coupling female side member 2 and the twisted polygonal boss 1-2 of the coupling male side member 1 are in the recording medium transport direction as described above. When the drum driving large gear 2-1 rotates in the direction opposite to the recording medium conveyance direction, the twisted polygonal hole 2-2 is maintained. The twisted polygonal pillar bosses 1-2 generate forces in directions away from each other. Therefore, the connection between the twisted polygonal hole 2-2 and the twisted polygonal pillar boss 1-2 can be easily released. Thereby, the connection between the coupling female side member 2 and the coupling male side member 1 is released.

As described above, the electrophotographic image forming apparatus A-1 according to the present embodiment has the twisted polygonal column boss 1-2 by driving the motor 3 in the direction opposite to the recording medium conveyance direction. The coupling male side member 1 and the coupling female side member 2 having the twisted polygonal hole 2-2 fitted into the twisted polygonal column boss 1-2 can be disconnected. Therefore, even if a motor having a large stop state holding torque of the motor is used, the operability of disconnecting the coupling is not increased, and the process cartridge 10 side is controlled by the reduction ratio reduced by the drum drive gear train GL1. The coupling male member 1 does not rotate. As a result, a motor having a large stop state holding torque can be used as a driving source, which enables high-speed image formation and a reduction in the cost of the apparatus itself.

Further, since the coupling mechanism can be used without increasing (enlarging) the operating force for disconnecting the coupling when the process cartridge 10 is attached / detached (detached), the usability is not reduced. Thus, the image quality can be improved.

Accordingly, the cost can be reduced and the performance can be improved by expanding the range of motor selection without lowering the image quality and the usability.

In the electrophotographic image forming apparatus A of this embodiment, a cam-shaped bearing 3-1 and a cam 3-2 as holding means shown in FIG. When the opening / closing cover 11 is open, the coupling male side member 1 and the large drum driving gear 2-1 can be held in the detached position by rotating the coupling male side member 1 and the drum driving large gear 2-1. This makes it possible to further improve the operability of the process cartridge attaching / detaching operation. That is, by rotating the cam 3-2 with respect to the bearing 3-1 in conjunction with the opening operation of the opening / closing cover 11, the cam 3-2 is moved in the thrust direction of the coupling female side member 2 and the cam 3-2 is moved. -2, the drum drive large gear 2-1 is moved in the same direction to maintain the state in which the coupling between the coupling male side member 1 and the coupling female side member 2 is released.

[Second Embodiment] The feature of the electrophotographic image forming apparatus according to the present embodiment is that even if the motor is rotated in the direction opposite to the transport direction in order to release the connection between the apparatus main body and the process cartridge. An advantage of the present invention is that the performance of the fixing device can be further enhanced by not driving the fixing device.

FIG. 4 is a sectional view of the electrophotographic image forming apparatus according to the embodiment. In the present embodiment, the same reference numerals are given to members having the same configurations as those in the above-described first embodiment, and description thereof will be omitted.

In FIG. 4, 1-1 is a photosensitive drum, 2-
1 is a drum driving large gear, 3 is a motor (stepping motor) capable of forward / reverse rotation driving, 4 is a photosensitive drum driving system reduction gear, 5 is a fixing driving system reduction gear a, 6-1 is a fixing driving system reduction gear b, 6-2, a pendulum arm for connecting the fixing drive system reduction gear a5 and the fixation drive system reduction gear b6-1, 7 a fixing unit, 7c a pressure roller drive gear, 8 a feed roller drive gear, and 9 a feeder A roller 10 is a process cartridge, 11 is an opening / closing cover, and 12 is a door switch for detecting opening / closing of the opening / closing cover 11.

Electrophotographic image forming apparatus A of the embodiment
Is a rotating shaft 3 of the motor 3 as shown in FIGS.
The driving gear 3a, the photosensitive drum driving system reduction gear 4, and the drum driving large gear 2-1 fixed to the driving gear b are rotationally driven by the rotating shaft 3b of the motor 3 to rotate the photosensitive drum 1-1. Is transmitted to the coupling female member 2 (see FIG. 2) to form a drum driving gear train GL1 as a driving force transmitting means. The drive gear 3a, the photosensitive drum drive system reduction gear 4, the large drum drive gear 2-1 and the feed roller drive gear 8 are driven to rotate by the rotating shaft 3b of the motor 3 and are fed to the transfer means 9 by the feed roller 9a. A feed roller driving gear train GL2 is configured as a conveying driving force transmitting means for transmitting a driving force for rotationally driving the roller. The driving gear 3a, the fixing drive system reduction gear a5, the fixing drive system transmission gear b6-1, and the pressure roller drive gear 7c
Constitutes a pressure roller driving gear train GL2 as a fixing driving force transmitting means which is driven by the rotation shaft 3b of the motor 3 to transmit a driving force for rotationally driving the pressing roller 7b to the fixing device 7. ing.

When the motor 3 is reversely driven by the fixing drive system transmission gear b6-1 with the pendulum arm 6-2 in the direction opposite to the recording medium conveyance direction, the pressure roller 7 of the fixing device 7 is rotated.
A drive release mechanism 35 as a release mechanism for releasing the drive of c is configured. When the motor 3 is reversely driven in the direction opposite to the recording medium conveyance direction and the fixing drive system reduction gear a5 rotates in the reverse direction, the drive release mechanism 35 drives the fixing drive system transmission gear b6-1 by the pendulum arm 6-2. Fixing device 7
Is configured to receive a force in a direction away from the pressure roller driving gear 7c. That is, the fixing drive system reduction gear a5
Is rotated in the reverse direction, the fixing drive transmission gear b6-1 is moved by the pendulum arm 6-2 to the support shaft 6 of the pendulum arm 6-2.
−2a as a fulcrum to move away from the pressure roller drive gear 7c.

The coupling mechanism in the electrophotographic image forming apparatus A of the present embodiment is the same as that shown in the first embodiment, and is provided at the longitudinal end of the photosensitive drum 1-1. It comprises a coupling male side member 1 as a connected cartridge coupling member and a coupling female side member 2 as a main body coupling member provided in the apparatus main body 30 (see FIG. 2). The coupling male side member 1 has a boss 1-2 as a polygonal pillar projection twisted at a side end thereof, and the coupling female side member 2 is formed integrally with the drum driving large gear 2-1. The coupling male side member 1 has a twisted hole 2-2 having a polygonal cross section for fitting with the boss 1-2 of the twisted polygonal column. And the twist direction of the boss 1-2 and the hole 2-2 is
When the photosensitive drum 1-1 and the large drum drive gear 2-1 rotate in the recording medium transport direction, they are attracted to each other and are molded in a direction to maintain a strong connection.

The door switch 12 in the electrophotographic image forming apparatus A of this embodiment is the same as that described in the first embodiment, and serves as a drive source drive control means for controlling the drive of the motor 3. Motor drive control unit 3
1 (see FIG. 7). When it detects that the open / close cover 11 is closed, it outputs a close detection signal to the motor drive control unit 31, and when it detects that the open / close cover 11 is opened, it outputs an open detection signal to the motor drive control unit 31. I do. The motor drive control unit 31 includes a CPU and the like. When a close detection signal is input from the door switch 12 and an image formation start signal is input from a control unit (not shown) that controls the entire electrophotographic image forming apparatus, the motor drive control unit 31 3 is configured to output a normal rotation drive signal to the motor 3 and output a reverse rotation drive signal to the motor 3 when an open detection signal is input from the door switch 12.

The driving operation of the electrophotographic image forming apparatus A in this embodiment will be described with reference to FIGS.

As shown in FIG. 4, when the process cartridge 10 is mounted on the proper mounting position of the apparatus main body 30 and the opening / closing cover 11 is closed, the twisted hole 2-2 of the coupling female side member 2 and the coupling 2-2 are formed. The boss 1-2 of the twisted polygonal pillar of the male member 1 is fitted, and the coupling female member 2 and the coupling male member 1 are connected. When the door switch 12 detects that the opening / closing cover 11 is closed, the motor 3 is pre-rotated in the recording medium conveying direction before the recording medium is conveyed. Here, the pre-rotation means that in response to the input of the image formation start signal, the motor 3 is restarted to rotate the photosensitive drum 1-1 again, and the image forming apparatus A executes a predetermined pre-image formation operation for a while. It means to let. By this pre-rotation operation, the motor 3 is driven to rotate forward, and the rotating shaft 3b rotates the driving gear 3a in the recording medium conveying direction (clockwise direction), whereby the photosensitive drum 1-1 in the process cartridge 10 and the coupling are rotated. The twisted polygonal pillar boss 1-2 of the male member 1 is firmly coupled to the twisted hole 2-2 of the coupling female member 2 which is the main body interface. The driving force of the motor 3 is transmitted to the large drum drive gear 2-1 of the coupling female side member 2 via the photosensitive drum driving system reduction gear 4, and further coupled through the hole 2-2 of the coupling female side member 2. The light is transmitted to the boss 1-2 of the male member 1 to rotate the photosensitive drum 1-1. The driving force of the motor 3 is transmitted to the large drum drive gear 2-1 of the coupling female member 2 via the photosensitive drum drive system reduction gear 4,
Further, the power is transmitted to a feed roller driving gear 8 that drives the feeding / transportation of the recording medium 22 to rotate the feed roller 9. Thereby, the recording medium 22 is conveyed from the feeding tray 23 into the apparatus main body 30 by the feeding roller 9. The driving force of the motor 3 is transmitted to the fixing device 7 via the fixing drive system reduction gear a5, the fixing drive system transmission gear b6-1, and the pressure roller drive gear 7c.
b is driven to rotate.

In this state, when the user opens the opening / closing cover 11 to remove the process cartridge 10 from the apparatus main body 30, the door switch 12 detects the opening, and the motor drive control unit 31 causes the motor 3 to operate.
For a certain period of time so as to rotate in the direction opposite to the direction of rotation when the recording medium is fed. This allows motor 3
Is driven in reverse, and the rotating shaft 3b rotates the drive gear a in the direction opposite to the recording medium conveyance direction (counterclockwise direction).
As a result, the drum driving large gear 2-1 of the coupling female side member 2 also rotates in the direction opposite to the recording medium transport direction, and the hole 2-2 of the coupling female side member 2 also rotates in the opposite direction to the recording medium transport direction. Is applied.

Here, the twisted polygonal hole 2-2 of the coupling female side member 2 and the twisted polygonal boss 1-2 of the coupling male side member 1 are in the recording medium transport direction as described above. When the drum driving large gear 2-1 rotates in the direction opposite to the recording medium conveyance direction, the twisted polygonal hole 2-2 is maintained. The twisted polygonal pillar bosses 1-2 generate forces in directions away from each other. Therefore, the connection between the twisted polygonal hole 2-2 and the twisted polygonal pillar boss 1-2 can be easily released. Thereby, the connection between the coupling female side member 2 and the coupling male side member 1 is released.

At this time, the fixing drive system transmission gear b6-
1 is connected to the fixing drive system gear a5 by the pendulum arm 6-2, so that when the motor 3 is driven in the reverse direction and the fixing drive system gear a5 rotates reversely, it is separated from the pressure roller drive gear 7c of the fixing device 7. Receives force in the direction. As a result, the fixing drive system transmission gear b6-1 is moved to the pendulum arm 6--6.
2, the pendulum arm 6-2 is moved in the direction of arrow Q away from the pressure roller driving gear 7c with the support shaft 6-2a as a fulcrum to release the engagement with the pressure roller driving gear 7c.

As described above, in the electrophotographic image forming apparatus A of this embodiment, the coupling male side member 1 and the coupling female side member 2 are driven by driving the motor 3 in the direction opposite to the recording medium conveyance direction. Can be disconnected. Therefore, similarly to the first embodiment, a motor having a large stop state holding torque can be used as a driving source, and it is possible to cope with high-speed image formation and reduce the cost of the apparatus itself.

Further, since the coupling mechanism can be used without increasing (enlarging) the operating force for disconnecting the coupling when the process cartridge 10 is attached / detached (detached), the usability is not reduced. Thus, the image quality can be improved.

Therefore, the cost can be reduced and the performance can be improved by increasing the range of motor selection without lowering the image quality and the usability.

In order to release the connection between the coupling male member 1 and the coupling female member 2, a motor 3 is provided.
Is driven in the direction opposite to the recording medium conveyance direction, the fixing drive system transmission gear b6-1 releases the engagement with the pressing roller driving gear 7c of the fixing device 7, so that the pressing roller 7c of the fixing device 7 is released. Does not rotate backward. For this reason, the performance of the fixing device 7 can be further exhibited without unnecessarily moving the positional relationship of the components inside the fixing device 7. That is, when the pressure roller 7c of the fixing device 7 is rotated in the reverse direction, the possibility that the position of the heater is shifted can be wiped out, and the performance of the fixing device 7 can be further exhibited.

The drive roller drive gear train GL2 is provided with a drive release mechanism having the same structure as the drive release mechanism 35 or a drive release mechanism such as a one-way clutch, so as to reverse the feed rotation. Rotational operation can be prevented, and a more stable recording medium feeding mechanism can be realized.

[Third Embodiment] A feature of the electrophotographic image forming apparatus of the present embodiment is that, when a recording medium is jammed during conveyance of the recording medium (hereinafter referred to as "paper jam"), the motor is driven in the recording medium conveyance direction. By rotating the coupling member in the opposite direction to release the coupling between the two coupling members, the usability is improved, and at the same time, the process cartridge can be disconnected from the main body drive system during the paper jam removal operation. The purpose is to reduce the load at the time.

FIG. 5 is a cross-sectional view of the electrophotographic image forming apparatus of this embodiment. In this embodiment, the same reference numerals are given to members having the same configuration as those of the first and second embodiments, and the description thereof will be omitted.

In FIG. 5, 1-1 is a photosensitive drum, 2-
1 is a drum driving large gear, 3 is a stepping motor (hereinafter referred to as “motor”) capable of forward and reverse rotation drive, 4 is a photosensitive drum driving system reduction gear, 5 is a fixing driving system reduction gear a,
6-1 is a fixing drive system reduction gear b, 6-2 is a pendulum arm connecting the fixing drive reduction gear a5 and the fixing drive system reduction gear b6-1, 7 is a fixing device, 8 is a feed roller drive gear, and 9 is a feed roller drive gear. A feeding roller 10 is a process cartridge, and 11 is an opening / closing cover. Reference numeral 12 denotes a door switch for detecting opening / closing of the opening / closing cover 11, and 13 denotes a fixing device
Is a paper jam sensor that detects paper jam on the recording medium discharge side of the printer.

The coupling mechanism in the electrophotographic image forming apparatus A of this embodiment is the same as that shown in the first embodiment described above, and is provided at the longitudinal end of the photosensitive drum 1-1. It comprises a coupling male side member 1 as a connected cartridge coupling member and a coupling female side member 2 as a main body coupling member provided in the apparatus main body 30 (see FIG. 2). The coupling male side member 1 has a boss 1-2 as a polygonal pillar projection twisted at a side end thereof, and the coupling female side member 2 is formed integrally with the drum driving large gear 2-1. The coupling male side member 1 has a twisted hole 2-2 having a polygonal cross section for fitting with the boss 1-2 of the twisted polygonal column. And the twist direction of the boss 1-2 and the hole 2-2 is
When the photosensitive drum 1-1 and the large drum drive gear 2-1 rotate in the recording medium transport direction, they are attracted to each other and are molded in a direction to maintain a strong connection.

The jam sensor 13 and the door switch 12
As shown in FIG. 8, it is connected to a motor drive control unit 36 as drive source drive control means for controlling the drive of the motor 3. When detecting a paper jam, the jam sensor 13 outputs a paper jam detection signal to the motor drive control unit 36. When detecting that the open / close cover 11 has been closed, the door switch 12 outputs a close detection signal to the motor drive control unit 31 in the same manner as in the above-described first embodiment, to notify that the open / close cover 11 has been opened. Upon detection, an open detection signal is output to the motor drive control unit 36. The motor drive control unit 36 includes a CPU and the like. When a close detection signal is input from the door switch 12 and an image formation start signal is input from a control unit (not shown) that controls the entire electrophotographic image forming apparatus, the motor drive control unit 36 3 is configured to output a forward rotation drive signal to the motor 3 when a forward rotation drive signal is output to the motor 3 and an open detection signal is input from the door switch 12 or a paper jam detection signal is input from the jam sensor 13. I have.

The driving operation of the electrophotographic image forming apparatus A in this embodiment will be described with reference to FIGS. When the cover 11 is opened, the motor 3
Is operated in reverse to release the connection between the coupling male side member 1 and the coupling female side member 2 by the above-described first operation.
And the fixing drive system transmission gear b6-1 and the pendulum arm 6 when the motor 3 is driven in the reverse direction.
The operation of the drive release mechanism 35 composed of -2 is the same as that of the above-described second embodiment, and the description thereof will be omitted.

As shown in FIG. 5, when the process cartridge 10 is mounted on the proper mounting position of the apparatus main body 30 and the opening / closing cover 11 is closed, the twisted hole 2-2 of the coupling female side member 2 and the coupling 2-2 are coupled. The boss 1-2 of the twisted polygonal pillar of the male member 1 is fitted, and the coupling female member 2 and the coupling male member 1 are connected. When the door switch 12 detects that the opening / closing cover 11 is closed, the motor 3 is pre-rotated in the recording medium conveying direction before the recording medium is conveyed. Here, the pre-rotation means that in response to the input of the image formation start signal, the motor 3 is restarted to rotate the photosensitive drum 1-1 again, and the image forming apparatus A executes a predetermined pre-image formation operation for a while. It means to let. By this pre-rotation operation, the motor 3 is driven to rotate forward, and the rotating shaft 3b rotates the driving gear 3a in the recording medium conveying direction (clockwise direction), whereby the photosensitive drum 1-1 in the process cartridge 10 and the coupling are rotated. The twisted polygonal pillar boss 1-2 of the male member 1 is firmly coupled to the twisted hole 2-2 of the coupling female member 2 which is the main body interface. The driving force of the motor 3 is transmitted to the large drum drive gear 2-1 of the coupling female side member 2 via the photosensitive drum driving system reduction gear 4, and further coupled through the hole 2-2 of the coupling female side member 2. The light is transmitted to the boss 1-2 of the male member 1 to rotate the photosensitive drum 1-1. The driving force of the motor 3 is transmitted to the large drum drive gear 2-1 of the coupling female member 2 via the photosensitive drum drive system reduction gear 4,
Further, the power is transmitted to a feed roller driving gear 8 that drives the feeding / transportation of the recording medium 22 to rotate the feed roller 9. Thereby, the recording medium 22 is conveyed from the feeding tray 23 into the apparatus main body 30 by the feeding roller 9. The driving force of the motor 3 is transmitted to the fixing device 7 via the fixing drive system reduction gear a5, the fixing drive system transmission gear b6-1, and the pressure roller drive gear 7c.
b is driven to rotate.

In this state, when the paper jam is detected by the paper jam sensor 13, the motor 3 is controlled to rotate for a certain period of time in the direction opposite to the rotation direction when feeding the recording medium. As a result, the motor 3 is driven to rotate in the reverse direction,
b rotates the drive gear a in the direction opposite to the recording medium conveyance direction (counterclockwise direction). As a result, the drum driving large gear 2-1 of the coupling female side member 2 also rotates in the direction opposite to the recording medium transport direction, and the hole 2-2 of the coupling female side member 2 also rotates in the opposite direction to the recording medium transport direction. Is applied.

Here, the twisted polygonal hole 2-2 of the coupling female side member 2 and the twisted polygonal boss 1-2 of the coupling male side member 1 are in the recording medium transport direction as described above. When the drum driving large gear 2-1 rotates in the direction opposite to the recording medium conveyance direction, the twisted polygonal hole 2-2 is maintained. The twisted polygonal pillar bosses 1-2 generate forces in directions away from each other. Therefore, the connection between the twisted polygonal hole 2-2 and the twisted polygonal pillar boss 1-2 can be easily released. Thereby, the connection between the coupling female side member 2 and the coupling male side member 1 is released.

With the above structure, when the paper jam occurs, the motor 3 is driven in the direction opposite to the recording medium conveyance direction to release the coupling between the coupling male member 1 and the coupling female member 2. At the same time, the usability can be improved, and at the same time, the process cartridge 10 is connected to the coupling female side member 2 and the drive gear train GL during the recording medium removal operation.
1 to GL3 and the motor 3 can be separated from the main body drive system, so that the load at the time of the recording medium removal operation can be reduced.

In the electrophotographic image forming apparatus shown in this embodiment, as shown in FIG. 9, a power storage device is provided with a power storage unit 37 as a power storage means, and a power switch is turned off.
(Not shown) or the power supply circuit 39 detects that the power supply to the main body power supply 38 has been cut off, and the motor drive control unit 36 uses the power stored in the power storage unit 37 in conjunction with the detection of the power supply circuit 39. Control to drive the motor 3 in reverse. Thus, even when the main body power supply 38 is turned off, the process cartridge 10
Is not placed in a state where it cannot be taken out, and usability can be further improved.

(Other Embodiments) The electrophotographic photosensitive members shown in the above-described embodiments are not limited to the photosensitive drums, and include, for example, the following. First, a photoconductor is used as the photoconductor. Examples of the photoconductor include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and an organic photoconductor (OPC). For example, a drum-shaped or belt-shaped one is used as the shape on which the photoconductor is mounted. For example, in the case of a drum-type photoconductor, a photoconductor is deposited or coated on a cylinder of aluminum alloy or the like. It was done.

Various developing methods such as a known two-component magnetic brush developing method, a cascade developing method, a touch-down developing method, and a cloud developing method can be used as the developing method.

In the above-described embodiment, a so-called contact charging method is used for the structure of the charging means. However, as another structure, a metal shield made of aluminum or the like is provided around three sides of a conventionally used tongue wire. Naturally, a configuration may be used in which positive or negative ions generated by applying a high voltage to the tongue wire are moved to the surface of the photosensitive drum, and the surface of the drum is uniformly charged.

The charging means may be a blade (charging blade), a pad type, a block type, a rod type, a wire type, etc. other than the roller type.

As a method for cleaning the toner remaining on the photosensitive drum, a cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.

The process cartridge described above is
For example, an electrophotographic photosensitive member and at least one of the process means
It has one. Therefore, as an aspect of the process cartridge, in addition to the above-described embodiment, for example, an electrophotographic photosensitive member and a charging unit are integrally formed into a cartridge and can be attached to and detached from the apparatus main body. The electrophotographic photosensitive member and the developing means are integrally formed into a cartridge,
A device that can be attached to and detached from the device body. An electrophotographic photosensitive member and a cleaning means are integrally formed into a cartridge so that the cartridge can be attached to and detached from the apparatus main body. Further, there is a type in which an electrophotographic photoreceptor and two or more of the above-mentioned process means are combined into a cartridge to be integrally detachable from the apparatus main body.

That is, the above-described process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is detachable from the main body of the image forming apparatus. . In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive member are integrally formed into a cartridge so that the cartridge can be attached to and detached from the image forming apparatus main body. Further, it refers to a device in which at least the developing means and the electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachably mountable to the image forming apparatus main body. The process cartridge can be attached to and detached from the apparatus main body by the user himself. Therefore, the maintenance of the apparatus main body can be performed by the user himself.

Further, in the above-described embodiment, a laser beam printer is exemplified as the electrophotographic image forming apparatus. However, the present invention is not limited to this. For example, an electrophotographic copying machine, a facsimile machine, a word processor, etc. Of course, it is also possible to use it for the electrophotographic image forming apparatus.

[0071]

As described above, according to the electrophotographic image forming apparatus of the present invention, the driving source is driven in the direction opposite to the direction in which the recording medium is conveyed by the conveying means.
Releasing the strong connection between the main body coupling member and the cartridge coupling member in which the polygonal twisted hole of the main body coupling member and the projection of the twisted polygonal column of the cartridge coupling member are fitted and connected. Therefore, the cost can be reduced and the performance can be improved by expanding the range of the selection of the driving source without lowering the image quality or lowering the usability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electrophotographic image forming apparatus according to a first embodiment.

FIG. 2 is a perspective view of a main part showing main parts of a main body coupling member and a cartridge coupling member.

FIG. 3 is a perspective view of a main part of a holding mechanism for holding a disconnected state between the main body drive system and the process cartridge.

FIG. 4 is a cross-sectional view of an electrophotographic image forming apparatus according to a second embodiment.

FIG. 5 is a sectional view of an electrophotographic image forming apparatus according to a third embodiment.

FIG. 6 is a detailed view of a drive gear train.

FIG. 7 is a control block diagram of motor drive control of the electrophotographic image forming apparatus according to the first and second embodiments.

FIG. 8 is a control block diagram of motor drive control of an electrophotographic image forming apparatus according to a third embodiment.

FIG. 9 is a control block diagram illustrating another motor drive control of the electrophotographic image forming apparatus according to the third embodiment.

[Explanation of symbols]

 1 Coupling Male Side Member 1-1 Electrophotographic Photoconductor 1-2 Boss 2 Coupling Female Side Member 2-1 Large Drum Drive Gear 2-2 Hole 3 Motor 4 Photosensitive drum drive system reduction gear 5 Fixing drive system reduction gear a 6 Fixing drive system transmission gear b 6-1 Fixation drive system transmission gear 6-2 Pendulum arm 7 Fixer 8 feeding roller gear 9 conveying means 9a feeding roller 10 process cartridge 11 opening / closing cover 12 door switch 13 jam sensor 26 charging means 27 developing means 28 Cleaning means 35 {drive release mechanism GL1} drum drive gear train GL2 {feed roller drive gear train GL3} pressure roller drive gear train

Claims (9)

[Claims] 1. An electrophotographic image forming apparatus for forming an image on a recording medium, wherein a process cartridge is detachable from an electrophotographic image forming apparatus main body. A main body coupling member, (b) an electrophotographic photosensitive member, a process means acting on the electrophotographic photosensitive member, and a polygonal twist of the main body coupling member provided integrally with the electrophotographic photosensitive member. Mounting means for removably mounting a process cartridge having a cartridge coupling member having a twisted polygonal column projection that fits into the hole formed therein, (c) a drive source capable of forward and reverse rotation drive, and (d) D) a driving force transmitting means driven by the driving source to transmit a driving force for rotating the electrophotographic photosensitive member to the main body coupling; Conveying means for conveying the main body coupling member, wherein the polygonal twisted hole of the main body coupling member and the projection of the twisted polygonal pillar of the cartridge coupling member are fitted and connected. An electrophotographic image forming apparatus, wherein the connection between the cartridge and the cartridge coupling member is released by driving the driving source in a direction opposite to a direction in which the recording medium is conveyed by the conveying means. 2. The apparatus according to claim 1, further comprising a main body opening / closing member for opening and closing the process cartridge when the process cartridge is attached to and detached from the mounting means, and a state of disconnection between the cartridge coupling member and the main body coupling member. 2. The electrophotographic image forming apparatus according to claim 1, further comprising: holding means for holding the member in an open state. 3. A fixing device for fixing an image on the recording medium, and a driving force transmission for fixing which is driven by the driving source and transmits a driving force for driving the fixing device to the fixing device. Means for transmitting the driving force to the fixing means when the driving source is rotationally driven in a direction opposite to the direction of conveyance of the recording medium by the conveying means. 2. The electrophotographic image forming apparatus according to claim 1, further comprising a release mechanism for releasing. 4. A transport driving force transmitting unit driven by the driving source to transmit a driving force for driving the transport unit to the transport unit, wherein the transport driving force transmitting unit includes: 2. The image forming apparatus according to claim 1, further comprising: a release mechanism configured to release transmission of a driving force to the transport unit when the drive source is rotationally driven in a direction opposite to a transport direction of the recording medium by the transport unit. 3. Electrophotographic image forming apparatus. 5. The apparatus according to claim 1, further comprising a main body opening / closing member for opening / closing the process cartridge when attaching / detaching the process cartridge to / from the mounting means, and a detecting means for detecting that the main body opening / closing member is opened. The main body coupling member and the main body coupling member are driven by driving the drive source in a direction opposite to a conveyance direction of the recording medium by the conveyance unit in conjunction with the detection unit detecting that the main body opening / closing member is opened. The electrophotographic image forming apparatus according to claim 1, wherein the connection with the cartridge coupling member is released. 6. A recording medium detecting means for detecting a recording medium clogging of the recording medium, wherein the recording medium detecting means detects the recording medium clogging of the recording medium, 2. The connection between the main body coupling member and the cartridge coupling member is released by driving a driving source in a direction opposite to a direction in which the recording medium is transported by the transport unit. 3. Electrophotographic image forming apparatus. 7. A power supply circuit for supplying power to the main body of the electrophotographic image forming apparatus, a power storage means for storing power, and a power supply circuit for detecting that the power supply to the main body power supply is stopped. In response to the power supply circuit detecting that the power supply to the main body power supply has stopped, the driving source is switched to the recording by the transport unit using the power stored in the power storage unit. 2. The electrophotographic image forming apparatus according to claim 1, wherein the connection between the main body coupling member and the cartridge coupling member is released by rotationally driving the medium in a direction opposite to a transport direction of the medium. 3. 8. An electrophotographic image forming apparatus according to claim 1, wherein said driving source is a stepping motor. 9. The process cartridge is a charging unit for charging the electrophotographic photosensitive member as the process unit, and develops an electrostatic latent image formed on the electrophotographic photosensitive member with a developer. Developing means for cleaning, at least one of cleaning means for removing a developer remaining on the electrophotographic photoreceptor, and a front electrophotographic photoreceptor are integrally formed into a cartridge, and the electrophotographic image forming apparatus main body is The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is detachable.