JPH06138722A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device in which the exposed part of a photosensitive body is covered when jamming occurs and jamming processing is easily performed by inserting a hand. CONSTITUTION:A flexible shielding member 32 which can be moved by the winding of a motor m1 and a plate-like shielding member 36 which can be moved by the winding of a motor m2 are respectively set at respective aperture parts facing to the transferred area and the exposed area of an image on a photosensitive belt 1 housed in a color process cartridge 30. When the jamming occurs, it is detected by sensors S1 to S3, and the motors m1 and m2 are made in an off-state, so that the surface of the photosensitive body is shielded and the cartridge 30 is moved to a retreat position by driving a motor M1, and then jammed paper is easily removed by inserting the hand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus for forming an image on a transfer material such as a copying machine or a printer. More specifically, each process material for image formation including an image carrier is unitized. The present invention relates to an image forming apparatus that can be attached and detached in this state.

[0002]

2. Description of the Related Art Many methods and apparatuses have been proposed for obtaining a color image using electrophotography. For example, JP-A-61
As disclosed in Japanese Patent Laid-Open No. -100770, a latent image is formed and developed on a photoconductor drum, which is an image forming body, according to the number of separated colors of an original image, and the latent image is transferred to a transfer drum each time the image is developed. There is a method in which a multicolor image is formed on the upper surface and then transferred onto a transfer material to obtain a color copy. The device by this method is
In addition to the photoconductor drum, it is necessary to provide a transfer drum having a size capable of transferring an image for one sheet on the peripheral surface thereof, and it is inevitable that the apparatus has a large size and a complicated structure.

Further, as disclosed in, for example, Japanese Patent Laid-Open No. 61-149972, latent images are formed and developed on a photosensitive drum in accordance with the number of separated colors of an original image, and the latent image is formed on a transfer material each time the development is performed. There is a method to obtain a multicolor color copy by transferring to. With this method, it is difficult to accurately superimpose multicolor images, and it is not possible to obtain a good-quality color copy.

Further, a latent image is formed on the photosensitive drum according to the number of separated colors of the original image and development with color toner is repeated, and the color toner images are superposed on the photosensitive drum and then transferred to obtain a color image. There is a way. The basic process for forming this multicolor image is described in Japanese Patent Application Laid-Open No. 60-75850 by the present applicant.
60-76766, 60-95456, 60-95458, 60-15847
It is disclosed in Japanese Patent Publication No. 5 and the like.

In a multicolor image forming apparatus which obtains a color image by such superposition, a plurality of developing devices accommodating color toners of different colors are arranged around the periphery of the photosensitive drum. Generally, the photosensitive drum is rotated a plurality of times to develop a latent image on the photosensitive drum to obtain a color image.

Particularly in the case of a color image forming apparatus, such an image forming apparatus is provided with a plurality of developing devices and a plurality of toner replenishing devices corresponding thereto, which complicates the structure of the image forming unit and causes a process problem. Inspect each of the materials individually,
It is extremely difficult to replace or replenish.

Therefore, at least the photosensitive member and the cleaning member are integrated, or the photosensitive member, the developing device, the cleaning member, and the like are housed in an integrated cartridge and mounted in the apparatus main body in a unit state, and as required for maintenance. The structure is such that the cartridge can be detached from the main body of the apparatus by a simple operation.

[0008]

When such a cartridge is formed, the photosensitive member has a structure in which most of the photosensitive surface is shielded. However, since the image exposure area and the transfer area are exposed, the inside of the apparatus is reduced. Even when it is attached to the device, dust, paper dust, etc. may adhere to it, and if it is removed from the apparatus, it may be touched by a hand or another device to stain or damage the photosensitive surface.

Therefore, it is effective to provide a shielding member to protect the photosensitive surface by always shielding the exposure and transfer areas of the photosensitive member except when the image forming process is operating. Furthermore, even if the transfer material is not properly conveyed (jam) even during the image forming process, it is necessary to insert the jammed paper to remove the jammed paper, which may damage the photoconductor. SUMMARY OF THE INVENTION It is an object of the present invention to solve this problem and to provide an image forming apparatus which does not damage a photoconductor during jam processing even when a jam occurs and has improved processability.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus equipped with a detachable process cartridge containing at least an image carrier and a cleaning member, when the transfer material fails to be conveyed (jam). The image forming apparatus is characterized in that the shielding member provided in the image transfer area is closed and the process cartridge is retracted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the image forming apparatus of the present invention is shown in FIGS.

FIG. 1 is a cross-sectional structural view of an image forming apparatus of the present invention. In FIG. 1, reference numeral 1 is a flexible photosensitive belt which is a belt-shaped image carrier, and the photosensitive belt 1 is a rotating roller 2 and It is installed between 3 and is conveyed in the clockwise direction by the driving of the rotating roller 2.

Reference numeral 4 denotes a support member, that is, a guide member fixed so as to be inscribed in the photosensitive belt 1. The photosensitive belt 1 is tensioned by the urging action of the rotating roller 3 toward the outside. The inner peripheral surface is rubbed against the guide member 4.

Therefore, the photoconductor on the outer peripheral surface of the photoconductor belt 1 is always kept in a constant relation position with respect to the surface of the guide member 4 even during conveyance, so that a stable image forming surface can be formed. .

6 is a scorotron charger as a charging means, and 7
Is a laser writing system unit as an image exposing means, 8 to 11
Are a plurality of developing means, that is, developing devices, each containing a developer of a specific color, and these image forming means are arranged so as to face the outer peripheral surface of the photosensitive belt 1 with the guide member 4 on the back side. To be done.

In addition to the optical system shown in the figure, the laser writing system unit 7 also includes an optical system in which a light emitting section and a converging optical transmission body are integrated.

Each of the developing units 8, 9, 10, and 11 contains, for example, each of yellow, magenta, cyan, and black developers, and is provided with each developing sleeve that keeps a predetermined gap from the photosensitive belt 1, It has a function of developing the latent image on the photoreceptor belt 1 by a non-contact developing method. Unlike the contact development, this non-contact development has an advantage that it does not hinder the movement of the photosensitive belt.

Reference numeral 12 is a transfer device, 12A is a static elimination bar, 13 is a cleaning unit, that is, a cleaning device, and the blade 13A of the cleaning device 13 and the toner carrying roller 13B are located at a position separated from the surface of the photosensitive belt 1 during image formation. As shown in the drawing, the surface of the photoconductor belt 1 is pressed against the surface of the photoconductor belt 1 only during cleaning after the image is transferred.

The color image forming process by the color image forming apparatus is performed as follows.

First, the formation of a multicolor image according to this embodiment is performed according to the following image forming system. That is, for example, data obtained by a color image data input unit in which an image sensor scans an original image is processed by an image data processing unit to create image data, which is temporarily stored in an image memory. Next, the image memory is taken out at the time of recording and is inputted to a color image forming apparatus which is a recording unit, for example, shown in the embodiment of FIG.

That is, when a color signal output from an image reading apparatus separate from the printer is input to the laser writing system unit 7, the laser writing system unit 7 generates a semiconductor laser (not shown). The laser beam is rotated by the drive motor 7A. The polygon mirror 7 is rotated.
It is rotated and scanned by B, passes through the fθ lens 7C, and then the mirror 7
The optical path is bent by D, 7E, and 7F, and a bright line is formed by being projected onto the peripheral surface of the photoconductor belt 1 to which a charge is previously applied by the charger 6 as a charging means.

On the other hand, when the scanning is started, the beam is detected by the index sensor, the modulation of the beam by the first color signal is started, and the modulated beam scans the peripheral surface of the photosensitive belt 1. Therefore, a latent image corresponding to the first color is formed on the peripheral surface of the photosensitive belt 1 by the main scanning by the laser beam and the sub-scanning by the conveyance of the photosensitive belt 1. This latent image is yellow (Y) in the developing means.
Is developed by the developing device 8 loaded with the toner (visual medium), and a toner image is formed on the belt surface. The obtained toner image passes through the cleaning device 13, which is a cleaning means separated from the peripheral surface of the photosensitive belt 1 while being held on the belt surface, and enters the next copy cycle.

That is, the photoconductor belt 1 is recharged by the charger 6, and then the second color signal output from the signal processing unit is input to the writing system unit 7 and the above-mentioned first color signal is output. Writing is performed on the surface of the belt and a latent image is formed in the same manner as in the above case. The latent image is developed by the developing device 9 loaded with magenta (M) toner as the second color.

The magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image.

Reference numeral 10 denotes a developing device having cyan (C) toner, which forms a cyan (C) toner image on the belt surface based on a control signal generated by a signal processing section.

Further, reference numeral 11 denotes a developing device having a black toner, which is formed by superposing a black toner image on the belt surface by the same process. A DC or further AC bias is applied to each sleeve of each of these developing devices 8, 9, 10 and 11 to perform jumping development by a two-component developer which is a developing means, and a photoreceptor whose base is grounded. The belt 1 is adapted to be subjected to reversal development in a non-contact manner. As the development, non-contact development using a one-component developer can also be used.

The color toner image thus formed on the peripheral surface of the photosensitive belt 1 is transferred to the transfer material sent from the paper feeding cassette 14 through the paper feeding guide 15 at the transfer portion.

That is, the transfer material stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16 and one of the uppermost layers is carried out, and the timing of the transfer material is synchronized with the image formation on the photosensitive belt 1 via the timing roller 17. It is supplied to the transfer device 12.

The transfer material which has received the image transfer and charge removal is separated from the photosensitive belt 1 which suddenly changes its direction along the rotating roller 2 and is moved upward through the suction type conveyor belt 17A. On the other hand, after the image is fused by the fixing roller 18, it is discharged onto the tray formed on the upper lid 20 via the paper discharge roller 19.

On the other hand, the photosensitive belt 1 which has been transferred to the transfer material is further conveyed to remove the residual toner in the cleaning device 13 in which the blade 13A as a cleaning member and the toner conveying roller 13B are brought into pressure contact with each other. After the end, the blade 13A is separated again, and a little later, the toner conveying roller 13B smoothes the toner accumulated on the tip of the blade 13A, and then the toner conveying roller 13B is separated to start a new image forming process.

FIG. 6 is a timing chart of the above process.

In the image forming apparatus described above, the photoconductor belt 1 is provided with a charger 6 which is arranged to face the lower peripheral edge.
Each developing device 8, 9, 10, 11 and a cleaning device 13 arranged at the lateral end are incorporated into an independent color process cartridge 30 as shown in FIG. Is attached to and detached from the device body. The color process cartridge 30 is not necessarily limited to the one in which all of the above-mentioned process materials are built in, and at least the photosensitive belt 1 and the cleaning device 13 may be integrated.

The color process cartridge 30 further has a developer replenishing section 30A on the side of the cleaning device 13 and a waste toner cartridge 30B integrally with the guide member 4.
The developer replenishing section 30A has a function of replenishing toner to each developing device, and the waste toner cartridge 30B has a function of collecting waste toner removed by cleaning.

The color process cartridge 30 is inserted into and removed from the apparatus main body as follows. That is, as shown in FIG. 5 showing the AA cross section of the color process cartridge 30, a pedestal 50 is provided, which is slidably supported by engaging a pair of fixed guide rails 40 with bottom leg portions 50A, as shown in FIG. The color process cartridge 30 is mounted on the mount 50 and housed in the apparatus.

The gantry 50 integrally includes a rack plate 51 that meshes with a pinion P1 of a motor M1 on the apparatus main body side, and is tilted and slid so as to form a dip when viewed from an obliquely upper right direction by the rotation of the motor M1. It is attached to the main body.

The color process cartridge 30 has a set of guide members 31 in which arc-shaped slits are formed as shown in FIG. 2 on the peripheral surface of the photosensitive belt 1 facing the image transfer area.
Is installed.

The guide members 31 are located on both sides of the photosensitive belt 1 outside the image area, and a shielding member 32 for covering the image area is housed between the guide members 31 along the photosensitive surface.

The shielding member 32 is a flexible thin plate made of a spring metal plate, and a pair of cord members 33A and 33B (shown by a chain line) are provided at both ends of the shielding member 32. It is attached at a position where it can move within the slit formed by the member 31.

The other ends of the cord members 33A and 33B are the respective rotating shafts installed in the color process cartridge 30.
Locked to 34A and 34B. The rotating shaft 34A is coaxial with a gear G1 on the outer wall of the cartridge, and the gear G1 is connected via an intermediate gear IG1 to a motor m1 having an electromagnetic clutch (not shown) on the rotating shaft. On the other hand, the rotating shaft 34B is biased clockwise by a torsion spring 35 and rotated, and the cord member 33B is wound a plurality of times to keep the shielding member 32 in a position where the image transfer area of the photosensitive belt 1 is closed. ing.

Further, the color process cartridge 30
A plate-shaped shield member 36 is slidably housed in the inner surface of the exposure opening 30C.

A string member (shown by a one-dot chain line) 37 having one end locked to a rotating shaft 38 provided in the cartridge is attached to one end of the shielding member 36, and the other end has an exposure region. A pair of tension springs 39 stretched between the color process cartridge 30 and the color process cartridge 30 are attached to the outside, and the shield member 36 is kept in a position to close the opening 30C by the urging of the tension springs 39. .

The rotating shaft 38 is a gear G on the outer wall of the cartridge.
2 are coaxially integrated, and the gear G2 is an intermediate gear IG2.
Is connected to a motor m2 via an electromagnetic clutch (not shown) on the rotating shaft.

The motor m1 is operated, for example, as a predetermined period of the image forming process operation, for example, only during an operation period in which the photosensitive belt 1 is rotated. That is, for example, when the photoconductor belt 1 starts to be conveyed and rotated by operating a copy switch provided in the operation section of the apparatus, the motor m1 starts to operate, and at the same time, the electromagnetic clutch on the rotation shaft thereof is also turned on and the gear is rotated. After rotating G1 clockwise a predetermined number of times, it automatically stops. (The transfer portion opening operation A is shown in the timing chart of FIG. 6.) As a result, the cord member 33A is wound around the rotating shaft 34A against the bias of the torsion spring 35, and the shielding member 32 is wound as shown in FIG. Moves and retracts from the image transfer area of the photosensitive belt 1 to enable the transfer of the image to the transfer material.

The electromagnetic clutch on the rotary shaft of the motor m1 is turned off when the conveyance rotation of the photosensitive belt 1 is stopped at the end of a series of copying operations, and the rotary shaft 34A is released. Therefore, the shielding member 32 in the retracted position is attached to the rotary shaft 34B by the urging force of the torsion spring 35 and returns to the position shown in FIG. 2 again to shield the image transfer area of the photosensitive belt 1.

The operation of the motor m1 and the electromagnetic clutch on the rotary shaft thereof can be operated, for example, only during the image transfer period on the transfer material. (Indicated by transfer portion opening operation B in the timing chart of FIG. 6) That is, when the timing roller 17 starts rotating to start feeding the transfer material that is temporarily stopped, the operation of the timing roller 17 starts. In conjunction with the above motor m
The operation of 1 is started and the electromagnetic clutch is turned on at the same time.

Operation of the motor m1 and O of the electromagnetic clutch
The state of N is continued from the start of the operation of the timing roller 17 for the time when the trailing edge of the maximum transfer material used can pass through the image transfer area, and then automatically stops or returns to OFF and again as shown in FIG. First, the image transfer area of the photoreceptor belt 1 is closed.

On the other hand, the motor m2 also operates by turning on the power switch, for example, and at the same time the electromagnetic clutch on the rotating shaft is also turned on to rotate the gear G2 counterclockwise a predetermined number of times and then automatically. To be stopped.

As a result, the cord member 37 is wound around the rotary shaft 38 against the bias of the tension spring 39, and the shielding member 36 is exposed for exposure as shown in FIG. 3 prior to the time of image exposure. Opening 30C
It is further moved and retracted so that the original image can be exposed by the laser writing system unit 7.

The image forming apparatus of the present invention has, for example, the detachable color process cartridge 30 described above, and the image transfer area is provided in the image transfer area of the photosensitive belt 1 of the color process cartridge 30. In the image forming apparatus, which is provided with a cover member 32 that can be opened / closed, when a jam occurs during image formation, the shield member 32 is closed to set the photosensitive surface of the photoconductor belt 1 to a protected state, and then the color process cartridge 30. 7 is a block circuit diagram and FIG. 8 is a flow chart diagram when a jam occurs.

That is, photosensors S1, S2, and S3 for detecting the passage of the transfer material are provided at various points of the transfer material conveyance path, and the sensors located on the upstream side of the respective conveyances pass the transfer material. If a sensor located on the downstream side cannot detect the transfer material even after a lapse of a predetermined time after the detection of
A jam detection signal is output from the device and the jam occurrence of the transfer material is displayed on the jam display unit 81 provided on the operation panel (not shown). (J-1) When the controller 80 detects a jam (J-1), the motor m
1 and the electromagnetic clutch on the rotary shaft of the motor m1 are controlled to be turned off, and the shielding member 32 shields the image transfer area of the photosensitive belt 1.

In this embodiment, at the same time as the above-mentioned operation, the motor m2 and the electromagnetic clutch on the rotary shaft of the motor m2 are controlled to be turned off, and the exposure opening 30C of the photosensitive belt 1 is closed. (J-2) After the shield members 32 and 36 have been shielded or in parallel with the shield operation, the control unit 80 starts reverse rotation of the motor M1 and the color process cartridge 30 is at the mounting position, that is, the first position where image formation is performed. Is moved to a second position where jam is removed or toner is supplied or replaced. In the reverse rotation operation of the motor M1, the light shielding plate 52 on the upper surface of the cartridge is operated by the photo sensor S5.
It is stopped by being detected by. (J-3)
At the second position, a space for inserting a hand and performing a jam process is formed.

In this embodiment, the upper lid 20 is the shaft 20.
It is rotatably supported by the apparatus main body via A, and is rotated counterclockwise to open the lid and open the opening portion in the upper part of the apparatus main body. That is, the upper lid 20 has a fan-shaped gear 21 which is meshed with the pinion P2 of the motor M2 on the apparatus main body side integrally with the rotation base thereof, and is rotated counterclockwise from the position shown by the rotation of the motor M2 to a predetermined angle. Is opened and held. (J-4) When the upper lid 20 is opened, the transfer path for the upper transfer paper is opened, and the jam is easily handled.

When the occurrence of the jam is detected in this way, the above-mentioned shielding members 32 provided on the color process cartridge 30 are operated by the operations (J-1) to (J-4).
Both 36 and 36 are placed in the shielding position, and a space necessary for performing the jam processing is formed while the photoconductor belt 1 is protected, so that the jammed paper can be easily removed.

The color process cartridge 30 is returned to the mounting position, that is, the first position again by operating the reset button provided on the operation portion. That is, when the reset button is pressed, the motor M1 is rotated in the forward direction to move the color process cartridge 30 from the position shown in FIG. 4 toward the position shown in FIG. 1 again, and the light shielding plate 52 is detected by the photo sensor S4. Stopped at the position.

In synchronism with this, the motor M2 also starts a normal rotation operation, and the upper lid 20 is rotated clockwise to close the opening in the upper part of the apparatus main body.

The above-described color process cartridge 30 has the above-mentioned shielding member 32 and the same as when it is in the second position even when it is not mounted, that is, when it is detached from the outside of the apparatus.
36 is kept in the closed position.

Further, in the above embodiment, the shielding members 32 and 36
Although the motors m1 and m2 for performing the opening operation of the color process cartridge 30 have been described in the embodiment, the motors m1 and m2 are color process cartridges.
It is not required that the motors m1 and m2 are installed in the apparatus main body, and the motors m1 and m2 are fixed to the apparatus main body.
When the color process cartridge 30 is located at the first position, the gears attached to the gears G1 and G2 respectively
It is also possible to configure so as to mesh with 2, and the same operation as that incorporated in the color process cartridge 30 can be performed by such a configuration.

[0058]

According to the present invention, the photoreceptor is effectively prevented from adhering dust and dirt, and its life is remarkably improved.
Even when a jam occurs, the jam processing is performed without damaging the photoconductor, so that it is possible to provide an image forming apparatus that can use the photoconductor for a long time and can always record a high-quality image. It was

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus of the present invention.

FIG. 2 is a sectional configuration diagram of a process cartridge of the apparatus.

FIG. 3 is a sectional configuration diagram of a process cartridge of the apparatus.

FIG. 4 is a cross-sectional configuration diagram of main parts of the device.

FIG. 5 is a cross-sectional view of an essential part of the device.

FIG. 6 is a timing chart showing the operation of the present invention.

FIG. 7 is a block circuit diagram of the image forming apparatus of the present invention.

FIG. 8 is a flowchart of the present invention when a jam occurs.

[Explanation of symbols]

 1 Photoconductor belt 2 Rotating roller 12 Transfer device 13 Cleaning device 17 Timing roller 30 Color process cartridge 30C Opening 31 Guide member 32, 36 Shielding member 33A, 33B, 37 String member 34A, 34B, 38 Rotating shaft 35 Torsion spring 39 Tension spring 80 Control part 81 Jam display part M1, M2, m1, m2 Motor G1, G2 ... Gear

Claims (1)

[Claims] 1. An image forming apparatus comprising a detachable process cartridge containing at least an image carrier and a cleaning member, wherein a shielding member provided in an image transfer area of the image carrier is closed when a transfer material conveyance failure occurs. The image forming apparatus is characterized in that the process cartridge is moved to the retracted state.