JPH04296885A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device where the replacement workability of a printing device such as an electric discharge wire and a printing roller is improved, and a printing electrode is automatically covered with a protecting cover in the jam processing and the replacement of the printing device, and the cut of the electric discharge wire is prevented by carrying out the replace ment of the printing device from the direction side for carrying out the shift and mounting/demounting of a process cartridge. CONSTITUTION:An installation arm 123 for installing a printing device 120 is installed so that the printing device 120 can be replaced from the direction side for carrying out shifting and mounting/demounting of a process cartridge 30, and when printing is carried out by shifting the process cartridge 30 to a printing enabled position, the protecting cover L13 of a printing electrode 2' automatically retreats, and the printing electrode 12' is exposed, while if the process cartridge 30 is shifted to a prescribed position in order to carry out jam processing or the replacement of the printing device 120, the printing electrode 12' is automatically covered by the protecting cover L13.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer that transfers an image on an image carrier using a transfer device.

0002

BACKGROUND OF THE INVENTION In image forming apparatuses such as monocolor analog copying machines using electrophotography and copying machines and printers using semiconductor laser/LED scanning systems, various photoreceptors, developer carriers, and cleaning members with a durable life span are used. A part of the image forming means is made into a cartridge for replenishment and replacement when the developer and toner are exhausted, and the member that integrates the main parts of the image forming means is taken out of the apparatus for maintenance or replacement. It has been proposed that something is configured to do so. Furthermore, various configurations have been proposed in which the conveyance path of the transfer material on which an image is formed by the image forming means is opened to make it easier to take out the transfer material when clearing a jam.

[0003] As a representative configuration of these,
A photosensitive drum, a developing device, a cleaner, etc. are integrally attached to a support member as disclosed in Japanese Patent No. 54392,
A proposal has been made to make the image forming means removable from the main body of the apparatus to facilitate replacement and repair of each unit, and then Japanese Patent Laid-Open Publication No. 154255/1983 proposes a device that integrates the main parts of these image forming means and makes them disposable. Further, a printer configuration using a similar disposable cartridge and forming a latent image on a photosensitive drum by dot exposure scanning and writing using a semiconductor laser is disclosed in Japanese Patent Laid-Open No. 147366/1983. Furthermore, these publications disclose a configuration in which the upper housing of the divided structure is opened to open the transfer material conveyance path and take out the transfer material in the event of a jam, and the above-mentioned Japanese Patent Laid-Open No. 57
Japanese Patent Publication No. 154255 adopts a configuration in which a disposable process cartridge is replaceably disposed in an upper housing having a two-part structure, and attempts to improve the workability of cartridge replacement and ease of jam removal. In addition, with emphasis on ease of replacement of process cartridges, mainly replenishment toner cartridges and cleaning cartridges for recovered toner, the structure is divided into two parts. JP-A-58-1161 discloses an improved method.

[0004] Also, the above structure is vertically shaped, and Japanese Patent Application Laid-open Nos. 63-244058 and 63-244059,
This is proposed in Japanese Patent Application Laid-open No. 63-244064 and Japanese Patent Application Laid-open No. 1-179168, which aims to improve the same direction operation and jam handling.

[0005]

[Problems to be Solved by the Invention] However, if the upper exterior member is opened and the process cartridge is pulled out so that the transfer area is exposed, it is possible to improve jam handling and maintenance workability. However, the maintenance of the transfer device was not always satisfactory.

In particular, when clearing a jam around the transfer device, if the upper exterior member is opened as described above and the process cartridge is pulled out so that the transfer area is exposed, the thin discharge wire that is the transfer pole of the transfer device was exposed to the outside without being protected by any protective material. For this reason, when removing jammed paper, if jammed paper or a fingertip is caught on this discharge wire, it may easily be cut. Also, when replacing an old transfer device that has made 5,000 to 10,000 copies, you must be very careful not to touch the thin discharge wire of the transfer pole with your fingertips. It was a task that required a lot of effort. Furthermore, the transfer device was replaced by sliding it in the longitudinal direction of the transfer device and pulling it out, but this direction was lateral to the image forming apparatus. Therefore, if the image forming apparatus is placed side by side with other OA equipment, a desk, etc., remove the side plate after pulling the image forming apparatus out of the row of OA equipment or changing the orientation of the apparatus. I had to pull out the transfer device. Further, although there is no need to worry about the discharge wire breaking, the transfer roller used as a transfer device needs to be replaced when it becomes old after a certain number of copies are made.

The present invention has been made to solve these problems, and it is possible to prevent the discharge wire from being cut when dealing with a jam or replace the transfer device, and to prevent the transfer of the transfer device from moving or attaching/detaching the process cartridge. The object of the present invention is to provide an image forming apparatus that can perform image forming from the direction of image forming.

[0008]

[Means for solving the problem] The above object is to provide a process cartridge including an image carrier that can be moved and removed from one side of the main body of an image forming apparatus, and an exterior that is located above the cartridge and can be opened. In the image forming apparatus, the image forming apparatus has a transfer area in which an image is transferred by opening the exterior member and moving the process cartridge. The image forming apparatus is characterized in that the transfer device can be replaced from the one direction side by moving from a first position where the transfer area is exposed to a second position where the transfer area is exposed. The device is provided with a protective cover that protects the transfer pole, and when the transfer device is a single unit, when the transfer device is replaced, and when the transfer device is in the second position where the process cartridge exposes the transfer area. The protective cover of the transfer device automatically covers the transfer pole to protect it, and when the process cartridge is moved to the first position where image transfer is performed, the protection cover of the transfer device automatically covers the transfer pole to protect the transfer pole. This is achieved by an image forming apparatus characterized in that the cover is automatically retracted from a cover position that protects the transfer pole to enable transfer by the transfer device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image forming apparatus of the present invention will be explained with reference to the drawings shown in FIGS. 1 to 10.

FIG. 1 is a diagram showing the process cartridge in a first position for image transfer.

Reference numeral 1 denotes a flexible photoreceptor belt serving as a belt-like image carrier. The photoreceptor belt 1 is installed between rotating rollers 2 and 3, and is conveyed clockwise by the rotational roller 2. be done.

Reference numeral 4 denotes a support member or guide member fixed to the main body of the apparatus so as to be inscribed in the photoreceptor belt 1;
The photoreceptor belt 1 is brought into a tensioned state by the outward biasing action of the rotary roller 3, so that its inner circumferential surface slides against the guide member 4. Therefore, the photoreceptor belt 1
The photoreceptor on the outer circumferential surface of the photoreceptor is always maintained at a constant position relative to the surface of the guide member 4 during transportation, making it possible to form a stable image forming surface.

6 is a scorotron charger as a charging means; 7
8 to 11 are laser writing system units serving as image exposure means;
denotes a plurality of developing means, that is, developing devices, each containing a developer of a specific color, and each of these image forming means is arranged facing the outer peripheral surface of the photoreceptor belt 1 with the guide member 4 on the back side. be done.

In addition to the optical system shown in the drawings, the laser writing system unit 7 may also include an optical system that integrates a light emitting section and a convergent light transmission body.

Each of the developing devices 8, 9, 10, and 11 accommodates, for example, black, cyan, magenta, and yellow developers, respectively, and is provided with a developing sleeve that maintains a predetermined gap from the photoreceptor belt 1. It has a function of making the latent image on the photoreceptor belt 1 visible by a non-contact development method. Unlike contact development, this non-contact development has the advantage of not interfering with the movement of the photoreceptor belt.

12 is a transfer device; 13 is a cleaning device; the blade 13A and toner conveying roller 13B of the cleaning device 13 are kept at a position apart from the surface of the photoreceptor belt 1 during image formation; and during cleaning after image transfer. As shown in the figure, the surface of the photoreceptor belt 1 is pressed against the surface of the photoreceptor belt 1.

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, data obtained by a color image data input section in which an image sensor scans an original image is subjected to arithmetic processing in an image data processing section to create image data, which is temporarily stored in an image memory. The image memory is then taken out during recording and input to a recording section, for example, the color image forming apparatus shown in the embodiment of FIG.

That is, when a color signal output from an image reading device separate from the printer is input to the laser writing system unit 7, the color signal is generated by a semiconductor laser (not shown) in the laser writing system unit 7. The laser beam is transmitted to a polygon mirror 7 rotated by a drive motor 7A.
B, it is rotated and scanned by the mirror 7 via the fθ lens 7C.
The optical path is bent by D, 7E, and 7F, and the light is projected onto the circumferential surface of the photoreceptor belt 1, which has been charged in advance by the charger 6, which is a charging means, to form a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the first color signal is started, and the modulated beam scans the circumferential surface of the photoreceptor belt 1. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt 1 by main scanning by the laser beam and sub-scanning by the conveyance of the photoreceptor belt 1. This latent image is developed by a developing device 8 loaded with black (BK) toner (developing medium) in the developing means, and a toner image is formed on the surface of the photoreceptor belt. The obtained toner image passes through a cleaning device 13, which is a cleaning means, which is separated from the peripheral surface of the photoreceptor belt 1 while being held on the surface of the photoreceptor belt 1, and enters the next copy cycle. Note that the black (BK) toner has a spectral characteristic of transmitting infrared light so as to transmit semiconductor laser light.

The photosensitive belt 1 is charged again by the charger 6, and then the second color signal output from the signal processing section is input to the writing system unit 7, and in the case of the first color signal described above, the second color signal is inputted to the writing system unit 7. Writing is performed on the drum surface in the same manner as described above, and a latent image is formed. The latent image is developed by a developer 9 loaded with cyan (C) toner as a second color.

This cyan (C) toner image is formed in the presence of the previously formed black (BK) toner image.

A developing device 10 has magenta (M) toner, and forms a magenta (M) toner image on the drum surface based on a control signal generated by a signal processing section.

Furthermore, 11 is a developing device having yellow (Y) toner, which forms a yellow (Y) toner image in a superimposed manner on the belt surface by the same process. Direct current or even alternating current bias is applied to each sleeve of each of these developing devices 8, 9, 10, and 11, and jumping development is performed using a two-component developer serving as a developing means.
Development is performed on the photoreceptor belt 1 whose base is grounded in a non-contact manner. Note that as the development, non-contact development using a one-component developer can also be used.

The color toner image thus formed on the circumferential surface of the photoreceptor belt 1 is transferred to the transfer paper fed from the paper feed cassette 14 via the paper feed guide 15 in the transfer section.

That is, the top layer of the transfer paper stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and transferred to the photoreceptor belt 1 via the timing roller 17.
It is supplied to the transfer device 12 in synchronization with the above image formation.

The transfer paper on which the image has been transferred is reliably separated from the photoreceptor belt 1, which suddenly changes direction along the rotation roller 2, and heads upward via the suction type conveyor belt 17A. After the image is fused by the fixing roller 18, the sheet is discharged via the discharge roller 19 onto a tray formed on the upper lid 20, which is an upper exterior member.

On the other hand, the photoreceptor belt 1 that has completed the transfer to the transfer paper continues to be conveyed to the cleaning device 1 with the blade 13A and the toner conveying roller 13B in pressure contact state.
3, the remaining toner is removed, and after the removal is finished, the blade 13A is pulled away again. A little later, after the toner conveying roller 13B smoothes out the toner accumulated on the tip of the blade 13A, the toner conveying roller 13B is removed.
B is separated and a new image forming process begins.

The photosensitive belt 1, the charger 6, each developing device, and the cleaning device 13 are incorporated into an independent process cartridge 30 as process materials for image formation, and are integrally attached to and removed from the main body of the apparatus.

That is, inside the device, as shown in FIG. 10 showing the AA cross section, there is a pair of fixed guide rails 4.
0 is provided with a pedestal 50 that is slidably supported by engaging legs 50A on the bottom surface, and the process cartridge 30 is placed on the pedestal 50 and housed in the apparatus.

The pedestal 50 has an integral rack plate 51 that meshes with the pinion P1 of the motor M1 on the apparatus main body side, and when the motor M1 rotates, it moves diagonally upward and to the right as shown in FIGS. 3, 5, and 9. It moves in parallel to protrude from the side of the device body and is held in a predetermined position.

On the other hand, the upper lid 20 is rotatably supported by the apparatus main body via a shaft 20A, and is opened by rotating counterclockwise to open an opening at the upper part of the apparatus main body.

That is, the upper lid 20 has a sector gear 21 integrated in its rotational base that meshes with the pinion P2 of the motor M2 on the apparatus main body side, and the rotation of the motor M2 causes the rotation of the motor M2 in FIGS. 3, 5, and 9. As shown in the figure, it is rotated counterclockwise and held at a predetermined angle.

When the upper lid 20 is in the closed position, the light shielding plate 52 on the upper surface of the process cartridge 30 shields the photo sensor S1 installed in the main body of the apparatus from the outside, as shown in FIG.
In the FF position, the photoreceptor belt 1 faces the transfer area and is held at a position where the above-described image forming process is possible, that is, the first position.

Next, the relationship between the transfer device and the process cartridge will be explained with reference to FIG. FIG. 2 is an enlarged view of the area around the transfer device shown in FIG. 1 described above.

Attachment tubes 122 are provided at both ends of the transfer device 12 in the longitudinal direction (perpendicular to the plane of the paper). The main body of the image forming apparatus is provided with a mounting arm 123 to which the mounting cylinder 122 to which the transfer device 12 can be mounted at a predetermined position can be attached and detached. Then transfer device 1 as shown in the figure.
2 is attached to the image forming apparatus.

Arm plates 121 are provided at both ends of the transfer device 12 in the longitudinal direction.
is provided, and a lever L11 is pivotally supported by a rotating shaft L10 provided on the arm plate 121. V on lever L11
A lever L12 is also provided in the shape of a letter, and a protective cover L13 curved in an arc shape is attached to the tip of the lever L12 to cover the discharge wire 12' which is a transfer pole. A spring L14 is attached between the lever L11 and the arm plate 121 to rotate the lever L11, that is, the protective cover L13 counterclockwise.

On the other hand, the image forming apparatus has a fixed rotating shaft L20.
A lever L21 is provided which is pivotally supported by. The lever L21 is further provided with a lever L25 and a lever L22. Lever L25 and fixing pin L2
A spring L251 is stretched between the levers 52, and in the state shown in the figure, the levers L21, L25, and L22 are being rotated clockwise. In addition, the spring L251 is attached to the fixing pin L252.
As shown in the figure, the spring L2 is
51 is located on the lower side and the angle α between the spring L251 and the center line L' is larger, the clockwise rotational force becomes larger. Conversely, when the center line L' of the spring L251 is located on the upper side, a counterclockwise rotational force is generated, and similarly to the above, the larger the angle between the center lines, the greater the rotational force. A lever L23 is supported at the tip of the lever L22 by a rotating shaft L220.
is further provided. There is a pin L at the tip of lever L23.
232 is provided, and lever L1 is provided on the back side of lever L23.
It is in contact with 1. The opposite side of lever L23 is lever L.
As shown in the figure, a part of 23 is bent in the direction perpendicular to the upper surface of the paper, forming a bent portion L231. and lever L22
A spring L24 is attached between the lever L23 and the lever L23 to rotate the lever L23 clockwise. Therefore, the bent portion L231 contacts the end surface of the lever L22 in the plate thickness direction as shown in the figure, and cannot rotate further clockwise relative to the lever L22 from the state shown in the figure.

Next, the relationship between the process cartridge 30 and each of the levers mentioned above will be explained.

As mentioned above, FIG. 2 is an enlarged view of the area around the transfer device shown in FIG. 1. Therefore, the process cartridge 30 is held at a first position where the photoreceptor belt 1 faces the transfer area. At this time, the left end surface 301 of the process cartridge contacts the tip of the lever L21 as shown in the figure, and the pin L232 at the tip of the lever L23 contacts the tip of the lever L21.
The protective cover L13, which comes into contact with the lever L11 on the back side of the lever 23 and is attached to the tip of the lever L12, is in a state where the transfer pole 12' is fully opened as shown in the figure. Therefore, the toner image formed on the circumferential surface of the photoreceptor belt 1 in this state is transferred to the transfer paper.

FIG. 3 shows a state in which the upper cover 20 is opened and the process cartridge 30 is pulled out diagonally upward and to the right.

[0042] By pressing the open button provided on the operation section (not shown), the motor M2 rotates forward and the upper cover 20 is opened, and by pressing the switch MS2, an OFF signal is output and the motor M2 is stopped. . On the other hand, the motor M1 rotates forward, and the process cartridge 30 moves diagonally upward and to the right from the first position, and as shown in the figure, the light shielding plate 52 turns off the photosensor S2, and the process cartridge 30
is stopped at this position.

In this position, the process cartridge 30 retracts the photoreceptor belt 1 to a greater distance than the transfer device 12, and is held at the second position exposing the so-called image transfer area, and is used for inspection of the transfer area. Work such as jamming of transfer paper is performed. Note that in the process of moving to the second position, the pedestal 50 presses the side cover 60 of the apparatus main body against the bias to open it.

Furthermore, by pressing a close button provided on an operation section (not shown) of the upper lid 20, the motor M2 starts to rotate in reverse, the upper lid 20 is closed, and the switch MS1 is turned OFF.
The F signal is output and motor M2 stops. On the other hand, the motor M1 rotates in the opposite direction, and the process cartridge 30 is moved diagonally downward and to the left from the second position, and the light shielding plate 52 again turns off the photosensor S1 to the first position shown in FIG.
returned to position. Then, the photoreceptor belt 1 is made to face the transfer area again, and the above-described image forming process is made possible.

Further, if it is necessary to take out the process cartridge 30 outside the main body of the apparatus, from the state shown in FIG. 3, press the cartridge ejection button (
(not shown), the motor M1 continues to rotate in the forward direction, and the process cartridge 30 is further translated diagonally upward and to the right from the second position, and reaches a position where the cartridge can be installed and removed, as shown in FIG. The light shielding plate 52 turns off the photosensor S3 and is stopped.

At this position, the process cartridge 30 is in a state where it can be removed from the pedestal 50, and is taken out of the main body of the apparatus to perform work such as inspection and replacement of process materials.

Returning to FIG. 3, the explanation of FIG. 3 will be continued.

FIG. 3 is a transfer pole because the process cartridge 30 is held in the second position exposing the transfer area as described above, and operations such as checking the transfer area and clearing jams on transfer paper are performed. A situation is shown in which the transfer pole 12' is covered with a protective cover L13 to prevent the thin discharge wire from being caught by transfer paper or fingers and cut.

FIG. 4 is an enlarged view of the periphery of the transfer device shown in FIG. 3.

Since the process cartridge 30 has moved diagonally upward and to the right as shown in the figure, the lever L21 and the process cartridge 30 are no longer in contact with each other, and the spring L251 stretched between the fixing pin L252 and the hole at the tip of the lever L25 is released. As a result, the levers L21, L25, and L22 rotate clockwise about the fixed rotation axis L20. Therefore, the lever L23, which is supported by the rotating shaft L220 at the tip of the lever L22, is released from contact with the lever L11 as shown in the figure. Therefore, arm plate 12
The lever L11, which is pivotally supported on the rotation axis L10 of 1, has a spring L14 installed between the arm plate 121 and the lever L11, which rotates the lever L11 counterclockwise. Rotate. That is, lever L1
Transfer pole 12 attached to lever L12 integrated with 1
Rotate the protective cover L13 in the counterclockwise direction to cover the transfer pole 12' as shown.

FIG. 5 shows a situation in which the transfer unit is being installed and removed from the right side, which is the front of the main body of the image forming apparatus and is also the direction in which the process cartridge is moved and installed.

FIGS. 6 to 8 are enlarged views of the main parts.

In FIG. 6, the arm plate 121 of the transfer device 12
A protective cover L13 attached to levers L11, L12 and L12 which are pivotally supported on a rotating shaft L10 of
11 and L12 counterclockwise, and a spring L14 is attached between the arm plate 121 and the lever L11 so that the protective cover L13 covers the transfer device 12 as shown in the figure.
A transfer device 1 provided with a mounting tube 122 including a transfer pole 12'
2 will be referred to as a transfer unit 120. Therefore, when this transfer device unit is in a stand-alone state until it is attached to the main body of the image forming apparatus, the transfer pole 1
2' is always protected by the protective cover L13.

Next, the case where the transfer device unit 120 is removed from the main body of the image forming apparatus will be explained.

In FIG. 5, by pressing the opening button provided on the operation section (not shown), the top cover 20 is opened as described above.
Open the lid and pull out the process cartridge 30 diagonally upward and to the right. In FIG. 6, a fixed spring 1 as shown is attached to the bent end of the mounting arm 123 attached to the image forming apparatus.
24 is installed. The transfer device unit 120 is attached by inserting the mounting tube 122 into the bent portion at the tip of the attachment arm 123, and the hemispherical protrusion at the tip of the fixing spring 124 falls into the hole provided in the attachment tube 122. By this, the transfer device unit 120 is attached to the mounting arm 1.
23 is firmly fixed. Therefore, when removing the transfer device unit 120, move the transfer device unit 120 diagonally to the upper right of arrow A so that the fixing spring 120
It can be removed by pulling it out with such force that the hemispherical protrusion at the tip of the mounting tube 122 can escape from the hole provided in the mounting tube 122.

Next, according to FIG. 7, the transfer unit 120
I will explain the removal in a little more detail. When the transfer unit 120 is attached to the mounting arm 123, the lever L11 and the pin L232 at the tip of the lever L23 have a positional relationship as shown by the solid line in the figure.

When the transfer unit 120 is pulled out in the direction of the arrow A with the above force and moved in the direction of the arrow to the position of the transfer unit 120' shown by the dotted line, the lever L1
1 moves to the position of the lever L11' shown by the dotted line and comes into contact with the pin L232 at the tip of the lever L23. When the transfer unit 120 is further moved in the direction of the arrow to the position of the transfer unit 120'' shown by the dotted line, the lever L11 is also moved to the position of the lever L11'' shown by the dotted line. On the other hand, the pin L232 at the tip of the lever L23
11 as described above, the lever L11 moves from the lever L11' position to the lever L11'' position, causing the pin L232 to move to the pin L232' indicated by the dotted line.
be moved to the position of Since a spring L251 is stretched between the hole at the tip of the lever L25 and the fixing pin L252, the movement of the pin L232 causes the levers L23, L to move.
22 and L25 are rotated about the rotation axis L20 from the solid line position to the dotted line position against the tension of the spring L251. When the lever L11 moves slightly further in the direction of the arrow from the position of the lever L11'', the engagement between the tip of the lever L11'' and the pin L232' is released. and spring L2
Due to the spring force of 51, the levers L23, L22, L25 return from the dotted line position shown in the figure to the solid line position. At this time, the transfer unit 120 is also removed from the mounting arm 123, so that the transfer unit 120 is in a free state as a single unit. Therefore, by further pulling out in the direction of arrow B, the transfer unit 120 can move the process cartridge 30,
It can be removed to the right side of the image forming apparatus main body, which is the direction of attachment and detachment.

Next, the case of attaching the transfer device unit 120 to the main body of the image forming apparatus will be explained.

In FIG. 5, the transfer device unit 120 is inserted from the right side of the main body of the image forming apparatus in the same manner as described above, and moved in the directions of arrows B' and A'. In FIG. 6, the mounting arm 1 is attached to the mounting cylinder 122 of the transfer unit 120.
23 and push it in until the hemispherical protrusion at the tip of the fixing spring 124 falls into the hole provided in the mounting tube 122 to attach the transfer device unit 120 to the image forming apparatus main body. FIG. 8 shows a state in which the transfer device unit 120 is attached to the attachment arm 123 of the main body of the image forming apparatus. In the process of inserting the mounting tube 122 of the transfer unit 120 into the mounting arm 123, the lever L11 of the transfer unit 120 also comes into contact with the pin L232 at the tip of the lever L23,
Rotate the lever L23 to the state shown by the solid line in the figure. That is, the lever L22 is supported by a rotating shaft L220 at the tip of the lever L22,
The lever L11 comes into contact with the pin L232 at the tip of the lever L23 against the spring force of the spring L24 which acts to rotate the lever L23 clockwise, and the lever L23
Rotate to the state shown by the solid line in the figure.

Next, the lever L21 is rotated clockwise about the rotation axis L20 to the position of the lever L21' shown by the dotted line. As a result, the pin L232 at the tip of the lever L23 moves to the position of the pin L232' indicated by the dotted line. Lever L21
When the pin L232' at the tip of the lever L23' is slightly rotated clockwise from the position L21' indicated by the dotted line, the engagement between the pin L232' at the tip of the lever L23' and the tip of the lever L11 of the transfer unit 120 is disengaged. The lever L23' is then rotated clockwise around the rotation axis L220' by the spring force of the spring L24' to the lever L23'' position shown by the dotted line. This is the position where the portion L231'' comes into contact with the end surface of the lever L22' in the plate thickness direction as shown in the figure, and the position of the lever L23'' relative to the lever L22' is maintained. When this state is reached, if the force of clockwise rotation of the lever L21' is removed, the spring L21'
Due to the spring force of 251, the levers L21, L22, L25 return to the positions shown by solid lines. This state corresponds to L21, L22, L23, L25 in Fig. 4.
This is the state shown.

FIG. 11 is a diagram showing another embodiment.

[0062] The transfer device 12 is provided with a mounting cylinder 122,
The steps of attaching and detaching the attachment cylinder 122 to the attachment arm 123 of the image forming apparatus body and attaching and detaching the transfer device 12 to the image forming apparatus are the same as in the previous embodiment.

Arm plates 121 are provided at both ends of the transfer device 12 in the longitudinal direction.
A lever L12 is supported by a rotating shaft L10 provided on the arm plate 121, and a rotary solenoid RS is attached to the same shaft. A protective cover L13 that covers the transfer pole 12' is attached to the tip of the lever L12, and the transfer pole 12 is rotated by the rotation of the rotary solenoid RS.
′ can be covered or exposed. The figure shows a state in which the transfer pole, which can be transferred, is exposed. Then, as in the case of the embodiment described above, by pressing the opening button of the operation section (not shown), the upper lid 20 is opened, the process cartridge 30 is moved diagonally upward to the right, and the light shielding plate 52 is moved to the upper right.
When the photo sensor S2 is turned off, the process cartridge 30 is stopped at this position. In response to this signal, the rotary solenoid RS rotates counterclockwise so that the protective cover L13 covers the transfer pole 12'.

Next, by pressing the close button of the operation section (not shown), the upper lid 20 is closed, the process cartridge 30 is moved diagonally downward to the left, and when the light shielding plate 52 turns off the photosensor S1, the process cartridge 30 is closed. 30 is stopped at this position. In response to this signal, the rotary solenoid RS rotates clockwise to protect the protective cover L13.
is retracted, and the transfer pole 12' is exposed so that transfer is possible.

Further, some explanation will be given regarding the case of an image forming apparatus using a transfer roller.

In the case of the transfer roller, there is no need for a protective cover since there is no thin discharge wire that could be cut. However, in the case of a transfer roller, the transfer roller must be separated from the photoreceptor belt by a predetermined distance at least when not transferring, and the transfer roller must be in close contact with the photoreceptor belt via the transfer paper during transfer. Therefore, the transfer roller is usually attached to a mechanical component that moves the transfer roller toward and away from the photoreceptor belt as described above. Therefore, by configuring the transfer roller so that it can be attached and detached from the mechanical parts in a direction that allows the process cartridge to move and be attached and detached, it is possible to attach and detach the transfer roller from one direction.

[0067]

[Effects of the Invention] According to the present invention, the transfer pole is covered with a protective cover when clearing a jam or replacing the transfer device, thereby preventing the discharge wire from being cut, improving the workability of maintenance, and making it easier to replace the transfer device. By making it possible to move, attach and detach the process cartridge from the direction in which the process cartridge is moved, an image forming apparatus is provided in which the workability of replacing the transfer device is improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus to which the present invention is applied in a transferable state, and FIG. 2 is an enlarged view showing the main parts of the present invention in the state shown in FIG. FIG. 3 is a cross-sectional configuration diagram of an image forming apparatus to which the present invention is applied, with the transfer area exposed, and FIG. 4 is an enlarged view of the main parts of the present invention in the state shown in FIG. FIG. 5 is a cross-sectional configuration diagram of an image forming apparatus to which the present invention is applied, with a transfer device unit (transfer device) removed.
FIG. 6 is an enlarged view of the main parts of the present invention in the state shown in FIG. FIG. 7 is an enlarged detailed view of the main part of the present invention with the transfer device unit (transfer device) removed. FIG. 8 is an enlarged detailed view of the main part of the present invention with a transfer device unit (transfer device) attached. FIG. 9 is a cross-sectional configuration diagram of the image forming apparatus to which the present invention is applied, with the process cartridge pulled out to a detachable state and the transfer device unit (transfer device) being detached. FIG. 10 is a sectional view along line AA in FIG. 1. 1st
FIG. 1 is a cross-sectional configuration diagram of another embodiment.

[Explanation of symbols]

1...Photoreceptor belt
12...Transfer device 12'...Transfer pole
120...Transfer unit 121...Arm plate
122...Mounting tube 123...Mounting arm
124...Fixing spring 20...Top lid
30... Process cartridge 301... Process cartridge left end surface 40... Guide rail 50... Mount
L10, L20, L220... Rotating shaft L11, L12, L21, L22, L23, L25... Lever L13... Protective cover
L14, L24, L251...Spring L232...Pin
RS...Rotary solenoid S1, S2, S3...Photo sensor

Claims (2)

[Claims] 1. A process cartridge including an image bearing member that can be moved and removed from one side of an image forming apparatus main body, and an exterior member that is located above the process cartridge and can be opened. In an image forming apparatus in which a transfer area where an image is transferred is exposed by opening an exterior member and moving the process cartridge, the exterior member is opened and the process cartridge is moved from a first position where an image is transferred to a transfer area. An image forming apparatus characterized in that the transfer device can be replaced from the one direction side by moving the transfer device to a second position where the transfer device is exposed. 2. The transfer device is provided with a protective cover that protects the transfer pole, and when the transfer device is a single unit, when the transfer device is replaced, and when the process cartridge of the transfer device exposes the transfer area. When the process cartridge is in the second position, the protective cover of the transfer device automatically covers the transfer pole to protect it, and when the process cartridge is moved to the first position where image transfer is performed, 2. The image forming apparatus according to claim 1, wherein the protective cover of the transfer device is automatically retracted from a cover position that protects the transfer pole, thereby enabling the transfer device to perform transfer.