JPH0484172A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate the exchange of consumables, the maintenance and exchange of materials and jam treatment by moving a process cartridge from a 1st position to a 2nd position where attachment and detachment as well as a jam treatment are possible when a jam detecting means detects a jam and allowing the mounting and moving of the process cartridge to a 1st position when a jam release is detected. CONSTITUTION:Photosensors S 1, S 2 and S 3, etc., which detect the passage of the transfer material are disposed at the required points of the transporting path for the transfer material. The jam detection signals are outputted there from. The jam release signal is outputted when the transfer material is no longer detected by removing the jammed transfer material from the transporting path. The respective signals are inputted to a control section. The process cartridge 30 is moved from the 1st position in the device where image formation is possible to the 2nd position where attachment and detachment are possible. the process cartridge is also moved from the 2nd position again toward the initial first position. The exchange and transfer of the process materials and the easy and rapid treatment of troubles, such as jam of the transfer materials, are executed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic image forming apparatus that forms an image on a transfer material such as a copying machine or a printer.

[Background of the invention]

There are many ways to obtain color images using electrophotography.
A device has been proposed. For example, Japanese Patent Publication No. 61100770
As disclosed in the publication, a latent image is formed and developed in accordance with the number of separated colors of the original image on a photosensitive drum serving as an image forming member, and is transferred onto a transfer drum each time it is developed. There is a method of forming a multicolor image and then transferring it onto a transfer material to obtain a color copy. A device using this method requires a transfer drum large enough to transfer one sheet of image onto its circumferential surface in addition to the photoreceptor drum, and the device does not have a large and complicated structure. Inevitable.

Furthermore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-149972, a latent image is formed and developed on a photoreceptor drum according to the number of separated colors of the original image, and is transferred onto a transfer material each time it is developed. There is a way to obtain a multicolor copy. With this method, it is difficult to overlay multicolored images with high precision,
It is not possible to obtain a good quality color copy.

Another method is to repeatedly form a latent image on a photoconductor drum according to the number of separated colors of the original image and develop it with color toner, and then overlap the color toner images on the photoconductor drum and transfer the images to obtain a color image. . The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-open No. 60-75850 and No. 60-75850 by the present applicant.
-76766, 60-95456, 60-95
No. 458, No. 60-158475, and the like.

In a multicolor image forming apparatus that obtains color images through such superimposition, a plurality of developing units containing different colored toners are arranged around the periphery of the photoreceptor drum. The photosensitive drum is rotated multiple times to develop the latent image on the photosensitive drum to obtain a color image.

On the other hand, in image forming apparatuses such as monochrome analog copying machines using electrophotography and copying machines and printers using semiconductor laser/LED scanning systems, various photoreceptors, developer carriers, cleaning members, and developer toners that have a useful life are used. A part of the image forming means is made into a cartridge for replenishment and replacement when the image forming means is worn out, and the member that integrates the main parts of the image forming means is taken out of the apparatus for maintenance or replacement. Something has been proposed. 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.

A typical configuration of these is as disclosed in Japanese Patent Publication No. 58-54392, in which the photoreceptor drum, developer, cleaner, etc. are integrally attached to a support member, and can be pulled out from the main body of the apparatus, and each unit is Proposals have been made to make replacement and repair easier, and the next step was to integrate the main parts of these image forming means and make them disposable.
4255, and JP-A-59-147366 discloses a printer configuration that uses a similar disposable cartridge and forms a latent image on a photoreceptor drum by exposure scanning and writing using a semiconductor laser. has been done.

Further, these publications disclose a structure in which the upper housing of the split structure is opened to open the transfer material conveyance path and take out the transfer material in the event of a jam. A structure is adopted in which a disposable process cartridge is replaceably disposed in an upper housing having a two-part structure, and attempts are made 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 linting cartridges for recovered toner, the structure is divided into two parts, and the process cartridges are placed in the lower casing to facilitate maintenance work. Unexamined Japanese Patent Application Publication No. 1973 (1973)
It is disclosed in the publication No. 8-1161.

In addition, the above structure is made vertical, and JP-A-63-2
No. 44058, No. 63-244059, No. 63-24
No. 4064, Japanese Unexamined Patent Publication No. 1-179168, etc., have been proposed, and these are aimed at improving the same direction operation and jam handling.

[The problem that the invention attempts to solve]

However, if the developing device, image carrier, etc. are made into a process cartridge and are replaceable with respect to the apparatus main body, the process cartridge can be easily loaded into and removed from the apparatus main body.
In addition, there is no need to worry about toner or developer leaking or spilling from the developing device when it is inserted into or removed from the main body of the device, and it also has a process cartridge that does not cause these problems when dealing with transfer material jams. No compact printer has been proposed.

In addition, Japanese Patent Application Laid-Open No. 58-190961 proposes that in a printer with a two-part structure, the process cartridge installed in the upper housing is kept horizontal at all times to prevent waste toner from collapsing when the upper housing is opened. It is disclosed in the official gazette. Although efforts have been made to make loading and jam removal easier, the structure does not solve problems such as toner sagging and leakage during cartridge loading, jam removal, and other maintenance replacement operations.

In particular, Japanese Patent Laid-Open No. 58-2003 has a structure in which a disposable cartridge is provided in the upper casing with a two-part structure that facilitates jam handling.
72159, and Japanese Patent Application Publication No. 72159 proposes that a process cartridge is provided in the lower housing to facilitate replenishment and replacement of collected toner, and the process cartridge for developing, cleaning, photoreceptor drums, etc. is lifted upward when handling jams. The proposals in Publication No. 58-1161 are all contradictory in workability of process cartridge replacement and ease of jam removal. Furthermore, in these process cartridges, the developing section
The cleaning part is on the bottom and faces the transfer pole across the paper feed and conveyance path, so even if the cartridge is tightly sealed, the developer This causes toner to spill from the cleaner section, causing stains inside the machine and staining the transfer paper.

Furthermore, the printer disclosed in Japanese Utility Model Application Publication No. 63-195357 has a process cartridge built-in and a flat feeding and conveying path formed at the top. The problem with the transport section has not been solved because there are restrictions on the transport path between the parts. Furthermore, it is not easy to clear jams when split into two, the stacked paper feed structure of the upstand is not compact as a whole, and the opening angle of the upper housing is restricted when split into two, making it difficult for users to operate. have not yet provided an excellent device for this purpose.

Regarding color image forming bodies, as explained above, there are photoconductor drums with a photoconductor coated or vapor-deposited on the peripheral surface of the drum, as well as belts with a photoconductor coated on or mounted on a flexible belt. For example, a patent application filed in 1983 by the applicant
4-192874, etc. The shape of the belt-shaped image forming body (hereinafter also referred to as a photoconductor belt) is determined by stretching it between rotating rollers including a drive roller, so that space can be used effectively to construct a compact color image forming apparatus. It is valid in some cases. In addition, since the photoreceptor belt can run along a small curvature, it is possible to prevent poor separation of the transfer material by using a rotating roller with a small diameter and using this curvature to separate the transfer material. can.

In a color image forming apparatus using such a photoreceptor belt, each image forming means such as a charging means, an image exposure means, a plurality of groups of developing devices, and a cleaning means is connected to the outer peripheral surface of the photoreceptor belt. Each of these image forming means, including the photoreceptor belt, is housed as a unitized process cartridge that can be freely attached to and detached from the main body of the apparatus. be done.

In addition, the transfer material with the color toner image transferred to it is ejected onto a paper ejection tray installed on the top of the device with the copy side facing down, allowing the device to be installed in a small space. ing.

In recent years, Japanese Patent Laid-Open Publications No. 64-40850 and No. 63-244059 have disclosed configurations that use compact cartridges to solve the problems of transportability and jam handling, and that enable operations in the same direction.

Furthermore, Japanese Patent Application Laid-Open No. 63-85763 discloses a control concept that performs display output when the toner in the process cartridge is exhausted or when the photoreceptor has reached the end of its lifespan.
It satisfies all the requirements: ease of jam removal, no toner consumption during cartridge activation/operation, ease of replacement, and ability to perform all operations from one direction on the front of the device body. There has never been an image forming apparatus that is compact and has such easy-to-use functions.

As a result of solving and improving this point, the present invention facilitates the replacement of consumables, maintenance and replacement of materials, and jam handling.
A further object of the present invention is to provide an image forming apparatus configured such that all of the above operations can be performed from the same side of the apparatus.

[Means to solve the problem]

The above object is to provide an image forming apparatus in which a replaceable process cartridge including at least an image bearing member is inserted, a jam detecting means being provided in a transfer material conveyance path of the image forming apparatus, and the jam detecting means detecting a jam. When the jam detection means detects that the jam has been cleared, the process cartridge is moved from a first position where image formation is possible on the process cartridge to a second position where it is possible to mount and remove the jam and clear the jam. This is achieved by an image forming apparatus characterized in that it can be mounted and moved from the second position to the first position.

〔Example〕

An embodiment of the image forming apparatus of the present invention is shown in FIGS. 1 to 7.

In FIG. 1, ■ is a flexible photoreceptor belt that is a belt-like image carrier, and the photoreceptor belt 1 is installed between rotating rollers 2 and 3, and is driven clockwise by rotating roller 2. transported to.

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, and the photoreceptor belt 1 is brought into a tensioned state by the outward biasing action of the rotary roller 3. The inner peripheral surface of the guide member 4
Let it rub.

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt 1 are always maintained at a constant position relative to the surface of the guide member 4 even during conveyance, making it possible to form a stable image forming surface.

Reference numeral 6 denotes a scorotron charger as a charging means, 7 a laser writing system unit as an image exposure means, and 8 to 11 a plurality of developing means, that is, developing devices, each containing a developer of a specific color. The means is disposed facing the outer peripheral surface of the photoreceptor belt (with the kite member 4 on the back side).

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 units 8.9.10.11 accommodates, for example, yellow macenter, cyan, and black developers, respectively, and is provided with a respective developing sleeve that maintains a predetermined gap from the photosensitive belt 1, It has a function of making the latent image on the belt l 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; 12A is a static elimination bar; 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 l during image formation; and cleaning after image transfer is performed. Only when the photoreceptor belt 1 is pressed against the surface of the photoreceptor belt 1 as shown in the figure.

The process of forming a color image 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 processed by an image data processing section to create image data, which is stored in a star 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 rotated and scanned by a polygon mirror 7B rotated by a drive motor 7A, and passes through an fθ lens 7C to mirrors 7D and 7.
The optical path is bent by E and 7F, and the light is projected onto the circumferential surface of the photoreceptor belt l, 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 l. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt 1 by the main scanning by the laser beam and the sub-scanning by the conveyance of the photoreceptor belt 1. This latent image is developed by a developing device 8 loaded with yellow (Y) toner (developing medium) of the developing means, and a toner image is formed on the drum surface. The obtained toner image, while being held on the drum surface, passes under a cleaning device 13, which is a cleaning means, which is separated from the circumferential surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photoreceptor belt l is charged again by the charger 6, and then the second color signal outputted from the signal processing section is input to the writing system unit 7, and the second color signal is inputted to the writing system unit 7, and the second color signal is inputted to the writing system unit 7. In the same manner, writing is performed on the drum surface to form a latent image. The latent image is developed by a developing device 9 loaded with magenta (M) toner as a second color.

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

IO is a developing device having cyan (C) toner, which forms a cyan (C) toner image on the drum surface based on a control signal generated by a signal processing section.

Furthermore, 11 is a developing device having black toner, and forms a black toner image superimposed on the belt surface by the same process. These developing units 8, 9, 10 and 11
A direct current or even alternating current bias is applied to each sleeve, and jumping development is performed using a two-component developer as a developing means, and development is performed without contact on the photoreceptor bell whose base is grounded. It looks like this. Note that as the development, non-contact development using component developers can also be used.

The color toner image thus formed on the circumferential surface of the photoreceptor bell l-1 is transferred to a transfer material 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 material stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and transferred to the transfer device 12 via the timing roller 17 in synchronization with the image formation on the photoreceptor belt 1. supplied to.

The transfer material that has undergone image transfer and static electricity removal is transferred to the rotating roller 2.
The image is reliably separated from the photoreceptor belt 1, which suddenly changes direction along the direction of the photoreceptor belt 1, and moves upward via the suction type conveyor belt 17A, and after the image is fused by the fixing roller 18, it passes through the paper ejection roller 19 and is transferred to the top cover 20. It is discharged onto the formed tray.

On the other hand, the photoreceptor belt l that has completed the transfer to the transfer material continues to be conveyed to the blade 13A and the toner conveying roller 13B.
The remaining toner was removed in the cleaning device 13 which was brought into pressure contact with the blade 13A, and the blade 13A was removed again after the cleaning was completed. A little later, the toner supply roller 13B smoothed out the toner accumulated on the tip of the blade 13A. Afterwards, the toner supply roller 13B is separated and a new image forming process begins.

The photosensitive drum 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, as shown in FIG. 3 showing the AA cross section, inside the device, a pedestal 50 is provided which is slidably supported by engaging a pair of fixed guide rails 40 with legs 50A on the bottom surface. The process cartridge 30 is placed on the pedestal 50 and housed in the apparatus.

The pedestal 50 is connected to the pinion P1 of the motor Ml on the device main body side.
The rack plate 51 is integrally meshed with the rack plate 51, and as the motor M1 rotates, the rack plate 51 is moved diagonally upward in parallel as shown in FIG.

On the other hand, the upper lid 20 is rotatably supported by the apparatus main body via a shaft 2OA, and is opened by rotating counterclockwise to open an opening in the upper part of the apparatus main body.

That is, the upper lid 20 has a flat gear 21 integrated in its rotating base that meshes with a pinion P2 of a motor M2 on the apparatus main body side, and is rotated counterclockwise as shown in FIG. 2 by the rotation of the motor M2 to a predetermined position. is held at an angle of

The movement of the pedestal 50 and the opening of the upper cover 20, that is, the rotation of the motors M1 and M2, are automatically started at the timing of the process material replacement, inspection, or replenishment cycle and the occurrence of transfer material transport trouble. .

The process cartridge 30 has a counter function that adds up the frequency of use of the process materials it accommodates, and when it is newly installed in the apparatus main body, the protrusion member 31 on the side of the cartridge shown in FIG. 3 is installed on the apparatus main body side. Press the reset lever 35 of counter C to return the display of counter C to 0, record the number of times of use from then on, and set each predetermined number of uses, such as the number of uses in the durable life of grade 13A of the cleaning device 13, the number of times in the life of the drum, etc. When the frequency (reference value) is reached, the counter C outputs a signal S.

c Example] Cleaning durability replacement...20, 0OOc Drum life replacement...60,0OOC At the time of 60,000, the counter C is reset again by inserting a new process unit.

Based on this signal, the cycle of replacement and inspection of the photosensitive drum 1, the charger 6, each developing device, and the cleaning device 13 is detected.

Note that the protruding member 31 is described in the present inventor's actual publication No. 2829.
The proposal in Publication No. 5 is applied, thereby preventing the counter C from being reset again by the same cartridge 30.

In addition, the process cartridge 30 is used to determine the amount of toner remaining in the toner supply pump 30A and the amount of waste toner in the waste toner cartridge 30.
Each of the toner cartridges B is equipped with a sensor that detects the amount of collected toner, and when it is time to replenish or replace the toner, it is detected as shown in FIG.
A signal S' is transmitted to the main body of the apparatus via the connector 32 shown, and it is detected whether it is time for replenishment or replacement. At the time of replacement in the above-mentioned mening period or replenishment/replacement of consumable materials, a replacement display is displayed on the operation display section 60 in response to the signals s and s'.

On the other hand, photosensors Sl, S2, 53, etc., which detect the passage of the transfer material, are arranged at key points on the conveyance path of the transfer material. If the downstream sensor cannot detect the transfer material even after a predetermined time has elapsed, a jam detection signal S'' (not shown) is output to detect whether or not the transfer material has jammed.

Furthermore, each of the above-mentioned sensors outputs a jam detection signal while
By removing the jammed transfer material from the conveyance path, a jam release signal can be output when the transfer material cannot be detected again.

Each of the detected signals described above is input to a control section of the apparatus main body, and output as a signal for controlling the rotation of the motors M1 and M2. On the other hand, a jam indicator lamp Ll is lit on the operation display section 60.

Hereinafter, the process of controlling the rotation of the motors M1 and M2 using the above-mentioned symbols will be explained with reference to the control circuit diagram in FIG. 5 and the 70-chart shown in FIG.

The device has an operation/display unit 60 provided on the front side thereof, that is, the side indicated by arrow B in FIG. 1, and a lamp Ll as shown in FIG. Or the lamp L that displays the replenishment cycle.
2, and a reset button 61 for allowing the motors M1 and M2 to start rotating in the reverse direction.

The jam detection signal (S"), the replacement of process materials,
When the replenishment detection signal (s, s') is input to the control section of the main body of the apparatus, the lamps Ll and L2 are lit and displayed.

Furthermore, upon input of one of the detection signals, a signal is outputted to the power supply unit to supply power for forward rotation to the motors M1 and M2 at the same time as the lighting.

Due to the forward rotation of the motor Ml, the pedestal 50 moves from the position shown in FIG. 1 to the position shown in FIG.
At the position F, the rotation of the motor M1 is stopped.

As a result, the process cartridge 30 is moved from the first position in the apparatus, where image formation is possible, to the second position, where it can be removed from the apparatus, and is in a state where it can be easily removed from the pedestal 50, and process materials can be replaced. , inspection or replenishment can be carried out efficiently.

On the other hand, continuing or in parallel with this, the motor M2 rotates forward, and the upper cover 20 rotates from the angle shown in FIG. 1 to the angle shown in FIG. The rotation of the motor M2 is stopped at the angle at which the switch MS2 on the main body of the device is pressed to switch from OFF to ON.

Therefore, in conjunction with the movement of the process cartridge 30 described above, jam removal of the transfer material can also be easily performed.

When the process cartridge 30 is removed from the pedestal 50 for replacing or replenishing process materials, the process shown in FIG. 6(a)
By placing the cartridge 30 on the pedestal 50 again as shown in , the bottom of the cartridge 30 presses the switch MS3 and turns it off.
is switched to ON, a storage detection signal of the process cartridge 30 is inputted, and a signal for supplying reverse rotation power to the motors M1 and M2 is outputted.

As a result, the process cartridge 30 moves again from the second position to the original first position, and at the position where the light shielding plate 52 switches the photo sensor S4 of the apparatus main body from OFF to ON, the motor M1 stops, and each The process material is maintained in an imageable condition.

On the other hand, the upper cover 20 rotates clockwise due to the reverse rotation of the motor M2, and the switch MSI is turned on with the sector gear 21.
The apparatus stops at the angle at which it is switched from FF to ON, closes the opening at the top of the main body of the apparatus, and turns off the lamp L2, making it possible to copy.

In the case of clearing a jam of a transfer material, in the image forming apparatus of the present invention, by pressing the reset button 61 after clearing the jam, a switching circuit turns off the lamp LL, and a switching circuit turns on the motors Ml and M2 to reverse rotation. A power supply circuit for supplying power is formed respectively.

When the jam processing is completed, the transfer material is removed from the conveyance path, the photosensors Sl, S2, and S3 return to the state of not detecting the transfer material, and the jam release signal is output. The switching circuit and the power supply circuit are connected, the lamp L1 is turned off and the jam display is erased, and furthermore, the motors M1 and M2 start rotating in reverse to move the process cartridge 3o from the second position to the first position. Rotate the top lid 20 clockwise to close the lid.

Therefore, in the image forming apparatus of the present invention, if the removal of the transfer material is incomplete, the jam display will not be erased even if the reset button 61 is pressed, and the motors M1 and M2 will not be reversed, and the apparatus will continue to operate as shown in FIG. The condition shown in FIG.

In addition, from the viewpoint of operational safety, it is also possible to manually open and close the upper cover 20.
In this case, the operation is performed after confirming whether the lamp L1 is turned on or off.

FIG. 7 shows a transfer drum type image forming apparatus according to another embodiment of the present invention. The photoreceptor belt 101 and the process cartridge portion disposed around its periphery are approximately the same as those in the previous embodiment, but the transfer drum 200 is brought into contact with the transfer portion of the photoreceptor belt 101. rotates in the direction of the arrow (counterclockwise) while maintaining synchronization with the photoreceptor belt 101. A transfer material is wrapped around the outer periphery of the transfer drum 200, a toner image is transferred onto the wrapped transfer material, the transferred toner images are superimposed, and then separated from the transfer drum 200, and after fixing, the charge is removed. This is what was discharged onto the top.

A charger 2011 provided to electrostatically attract the transfer material is provided at the peripheral edge of the transfer drum 200. A winding member 202 for mechanically winding the transfer material around the transfer drum 200 is provided. has a roller at its tip and comes into contact only when it first wraps around the transfer drum 200. Further, a gripper 203 is provided on the peripheral surface of the transfer drum 200, and acts to hold the leading edge of the transfer material that is synchronously conveyed. A transfer device 204 electrostatically transfers the toner image on one inch of the photoreceptor belt onto a transfer material. 205 is a separation electrode, and 206 is a separation claw. In addition, 207 is a cleaner that can touch and separate the transfer drum 2 after separating the transfer material.
This is to remove adhering toner on 00.

The transfer material discharged from the paper feed force cera l-114 is transferred to the transfer drum 20 charged by the charger 201 while maintaining synchronization.
0, the transfer material is wound by the winding member 202, the leading edge of the transfer material is held by the gripper 203, and rotated to the transfer section, where the yellow is formed on the photoreceptor bell 81 inches by the transfer device 204. (Y) Transfer the toner image onto a transfer material. After completing the first transfer, the transfer drum 200 continues to rotate, producing a magenta (M) toner image in the second rotation, a cyan (c) toner image in the third rotation, and a black (BK) toner image in the fourth rotation.
The l-ner images are transferred in a superimposed manner. When the transfer of the four-color toner image is completed, the transfer material is transferred to the separation/elimination electrode 2.
In step 05, static electricity is removed, and the leading edge of the transfer material is released from being held by the separation claw 206, separated, and conveyed to the fixing roller 118.

In the image forming apparatus of this embodiment, the transfer drum 200 is located on the apparatus main body side and is movable and removable, and is not included in the process cartridge. Therefore, insertion and removal of the process cartridge, jam removal, etc. are performed in the same manner as in the previous embodiment.

〔Effect of the invention〕

According to the present invention, operations such as replacing, inspecting, and replenishing process materials in the image forming section can be carried out at appropriate intervals, and troubles such as transfer material jams can be easily and promptly dealt with without missing an opportunity. As a result, it has become possible to provide an image forming apparatus that is well inspected and maintained and can always copy high quality images.

[Brief explanation of drawings]

1, 2 and 7 are cross-sectional configuration diagrams of the image forming apparatus of the present invention, FIGS. 3 and 4 are sectional views and side views of essential parts thereof, and FIG. 5 is a control circuit diagram, FIG. 6 is a flowchart showing the control process. ■...Photosensitive drum 6...Charger 7...Laser writing system units 8-11...Developer 12...Transfer unit 13...
Cleaning device 14...paper feed cassette 20...top lid 21...sector gear 30...process cartridge 7ji 40...guide rail 50...mount 51...
Rack board 60...Operation/display section L I, L
2...Display lamp 5l-55...Photo sensor MSI, MS2...Switch Ml, M2...Motor

Claims (1)

[Claims] (1) In an image forming apparatus in which a replaceable process cartridge including at least an image bearing member is inserted, a jam detection means is provided in the transfer material conveyance path of the image forming apparatus, and when the jam detection means detects a jam. moves the process cartridge from a first position where image formation is possible to a second position where it allows attachment/detachment and jam removal, and when the jam detection means detects that the jam has been cleared, the process cartridge is moved to the second position. An image forming apparatus characterized in that it can be mounted and moved from a second position to a first position.