JPH02147575A - Image forming device - Google Patents

Abstract

PURPOSE:To automatically utilize a paper by branching the paper in transport on the upstream side of an image formation processing part and introducing said paper into an intermediate tray and supplying the paper after jam processing, when the paper transport jam is generated on the downstream side from the image formation processing part. CONSTITUTION:When the transport jam is generated between a copy processing part 3 and a paper discharge roller 48 to a CPU 90 judges the generation of jam, and continuously drives a transport clutch 101, and continuously revolves a resistor roller 43, and a branching solenoid 96 is driven, and a copying paper branching hook 6 is shifted, and then the transport rollers 72 and 74 are revolved by the drive of a transport clutch 99, and the copying paper is accumulated into an intermediate tray 54 through a copying paper transport part 7 from the copying paper branching hook 6. When the jam processing is carried out, and a reset switch 93 is operated, and a copy button is pressed, the CPU 90 drives a paper feeding clutch 97 and a transport clutch 98 in substitution for a transport clutch 100, and pulls out the copying paper stored in the intermediate tray 54 by a paper feeding roller 53, and copy processing is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image forming apparatus equipped with an intermediate tray that temporarily stores sheets on which an image has been formed once and supplies the sheets to an image forming processing section again.

<Prior Art> In an image forming apparatus such as an electrophotographic copying machine, there is provided a paper feeding section that supplies paper on which an image is to be formed, a first paper transport path that guides the paper supplied from the paper feeding section to an image forming processing section, It is equipped with an image forming processing unit that performs image forming processing on a document image using an optical electrostatic recording method, a second paper transporting unit that transports the paper on which the image has been formed to a paper ejection unit, and a second A fixing section is provided in the middle of the paper transport section to fix the formed image on the paper.

Incidentally, recently, in order to increase the number of functions in image formation and save labor, double-sided image forming functions, editing functions, etc. are sometimes added.

The double-sided image forming function branches the paper on which an image has been formed on one side from the middle of the second paper transport section, and transfers the paper to an intermediate tray (a tray provided inside the image forming apparatus that temporarily stores the paper). ), then the paper is taken out from the intermediate tray, merged into the first paper transport path, and the next original image is formed on the back side of the paper. In addition, the editing function performs image formation on a single sheet of paper corresponding to two or more originals, and the sheet on which the image has been formed is first led to the intermediate tray, and then the sheet is taken out from the intermediate tray and the above This is achieved by forming an image on the imaged surface.

When performing an image forming operation using an image forming apparatus equipped with the above-mentioned double-sided image forming function or editing function, a jam occurs inside the image forming apparatus or in the sorter (if a sorter is used). Assume a case.

In this case, conventionally, the operator stops all mechanical drives, inspects the inside of the image forming device or sorter, removes any paper remaining inside the machine, returns the system to its initial state, and then forms the image. It was normal to resume operation.

However, recently, in order to speed up image formation and save labor, automatic document feeders are sometimes used that automatically feed stacked documents one by one to a predetermined position on the exposed surface of the document. . Further, even without using an automatic document feeder, image formation processing may be performed on a plurality of copies of the same document.

In these cases, the sheets are sent out one after another from the paper feed section, so if a jam occurs as described above, a plurality of sheets will remain inside the image forming apparatus main body.

<Problems to be Solved by the Invention> As mentioned above, when multiple sheets of paper remain in the image forming device when a jam occurs, the sheets that have undergone image formation processing cannot be reused because the image of the original has already been formed. Although it cannot be used, no image is formed on paper that has not been subjected to image formation processing. However, since all the paper remaining in the machine is pulled out from the conveyance path when handling a jam, there is a problem that even non-image-formed paper can be folded or torn and cannot be reused.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can automatically reuse paper left in the apparatus without being subjected to image forming processing after a paper transport jam occurs, thereby saving paper. There is a particular thing.

Means and Effects for Solving the Problems> To achieve the above object, the image forming apparatus of the present invention includes a branch part provided in the middle of the conveyance path from downstream of the paper feeding part to the image forming processing part; a paper transport unit that transports the paper branched from the branch unit to the intermediate tray; a detection unit that detects that a paper transport jam has occurred downstream from the image forming processing unit; and a detection signal received from the detection unit. In this case, a conveying path driving means for driving a paper conveying path from downstream of a paper feeding section to an intermediate tray via a branching section, and a branching section driving means for operating a branching section to divert unimaged paper being conveyed. , when forming an image again, a paper feeding means is provided to feed the paper introduced into the intermediate tray to the image forming processing unit. If a paper transport jam occurs downstream from the
The paper being conveyed upstream of the image forming processing section is not subjected to any image forming processing. This paper is branched from the branching section, introduced into the intermediate tray through the paper transport path without passing through the image forming processing section, and fed when forming an image again after clearing the jam. can be subjected to image formation.

Further, the present invention includes a detection means for detecting a paper conveyance jam downstream of a branch section provided downstream from the image forming processing section for guiding the paper on which an image has been formed once to the intermediate tray. , a conveyance path driving means for driving a conveyance path from downstream of the paper feeding section to the intermediate tray via the branching section when receiving a detection signal from the detection means; and an image forming means for the paper passing through the image forming processing section. The image forming apparatus is provided with an image forming stopping means for stopping the forming process, and a paper feeding means for feeding the paper introduced into the intermediate tray in order to convey the paper to the image forming processing section when forming the image again after clearing the jam. It may be something.

With this image forming apparatus, if a paper transport jam occurs downstream of the above-mentioned branching section, the paper being transported along the transport path downstream from the paper feed section will pass through the image forming processing section without any image formation. After handling the jam,
When forming an image again, by feeding this paper, it is possible to form an image on this paper.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing examples.

FIG. 1 is a schematic diagram illustrating the internal mechanism of a copying machine equipped with an automatic double-sided copying function, an automatic document supply function, and an automatic transfer paper distribution function. A contact glass (11) is fixed to the upper part of the copying machine main body (1), and a reversible automatic document feeder (RADF) (12) is disposed on the contact glass (11). Also, there is a sorter S) on the transfer paper ejection side (left side of the figure) of the copying machine body (1).
are arranged inside the copying machine main body (1), and are provided on the upstream side of the optical system (2), the copy processing section G), the transfer paper transport section (4), and the copy processing section (3), and the transfer paper transport section (4)
A transfer paper branching claw (6) for branching the transfer paper being transported, and a transfer paper transporting section (7) for transporting the branched transfer paper from the transfer paper branching claw (6) to an intermediate tray (54). ing.

First, to briefly explain the structure of the RA D F (12), the RA D F (12) consists of a casing (12
L) includes an original transport unit (122) that transports the original to a predetermined position on the touch glass (11), and an original that transports the original (double-sided original) whose back side is to be copied after the front side is copied to the above-mentioned predetermined position. Original reversing unit (123) for taking out and reversing the document
It has Further, a document collection section (124) is provided at the top of the casing (121), from which exposed documents (documents to be discharged) are discharged, and a document transport section (122) is provided.
) is provided with a paper feed section (125) that automatically feeds the document to the document transport section (122).

The optical system (■) of the copying machine main body (1) includes a light source (21), a mirror (22), (23), <24), a lens (25),
The light source (21) exposes an original (not shown) set on the contact glass (11) and reflects light from the original to the mirror (22).

(23), (24), lens (25), and mirror (
26) to the copy processing section (3).

The copy processing section (3) includes a charger (32), a blank lamp (37), a developing device (33), a transfer charger (34), and a separation charger around a photosensitive drum (3I) that rotates in one direction. (35), and cleaner (
3B) are arranged in this order, and the photoreceptor drum (3B) is uniformly charged by the charger (32).
By forming an image of the reflected light from the original on the surface of 1), an electrostatic latent image corresponding to the original image is formed, and unnecessary parts are removed by a blank lamp (37), and the electrostatic latent image that has been removed from this unnecessary part is The latent image is developed into a toner image by the developing device (33), the toner image is transferred to the surface of the transfer paper by the transfer charger (34), and the toner image is transferred from the surface of the photoreceptor drum (31) to the transfer paper by the separation charger (35). After removing the toner, the remaining toner is collected by a cleaner (36).

The transfer paper conveyance section (4) is a paper feed cassette (13a) that is removably installed in a predetermined position of the copying machine main body (1).

(13b) or a paper feed roller (41a) that feeds the transfer paper one sheet at a time from the scooking bypass (14), (4
th).

(41, c), paper feed path (42a), (42b)
, (42c), registration roller (43), conveyance roller (44), conveyance belt (45), heat fixing device (46)
, transport rollers (47), (51), and a discharge roller (48). Transfer paper detection switch (94)
(95) are switches provided downstream of the copy processing section (3) and downstream of the discharge roller (48), and are made of, for example, a micro switch or a photosensor, and are used to prevent the leading edge of the transfer paper from passing through. It turns on when the transfer paper passes, and turns off when the trailing edge of the transfer paper passes.

Furthermore, the transfer paper conveyance section (4) includes a transfer paper conveyance section (4a) for feedback in addition to the above.

The transfer paper conveyance section (4a) includes a switching claw (49) provided between the conveyance roller (47) and the conveyance roller (51),
A curved first guide space (50) that temporarily guides the transfer paper, and a transport roller (51) that transports the transfer paper backwards from the first guide space (50). ), which allows the transfer paper to be fed backwards.)
Second guide space (52), conveyance roller (5B) (57
), an intermediate tray (54), a secondary paper feed roller (53), transport rollers (58) (59), and a paper feed path (55). When copying is performed only once on one sheet of transfer paper, set the switching claw (49) to the position indicated by the broken line in Figure 1.
The transfer paper is transported via a transport roller (51) and a discharge roller (48) and is discharged toward the sorter (8). When performing double-sided copying on one sheet of transfer paper, use the switching claw (49).
is switched to the position indicated by the solid line above, and after front side copying, the transfer paper is introduced into the intermediate tray (54), and then transferred again to the intermediate tray (54).
54) and form an image on the back side.

Further, a transfer paper branching claw (6) is provided between the registration roller (43) and the conveyance roller (44) to branch the transfer paper being conveyed in the transfer paper conveyance section (4) when a jam occurs. , at the solid line position in FIG.
), and when the transfer paper is switched to the position indicated by the broken line, the transfer paper can be branched and fed directly toward the intermediate tray (54). On the branching side of the transfer paper branching claw (6), there are a transport roller (72), a transport path (73), and a transport roller (72), which transport the transfer paper branched from the transfer paper branching claw (6) to the intermediate tray (54). 74), and a curved conveyance path (75). These conveyance rollers (72) (74) and conveyance paths (73) (75) form a transfer paper conveyance section (7).

The sorter 8) has a first guide member (81) at a predetermined position that guides the transfer paper discharged from the discharge roller (48).
A switching member (82) is installed which operates in accordance with the sorted state and non-sorted state and switches the transfer paper guiding direction. (83) is a suction type belt that pulls up the transfer paper in the sorted state, and (84) is a suction type belt (84).
3) is a second guide member that is movable up and down over the entire range. In the sorting state, the suction belt (83) and the second guide member (84) move the predetermined sorting bin (
85) so that the transfer paper can be ejected. In the non-sort state, the transfer paper is discharged into the non-sort bin (87) by a third guide member (86) whose mounting position is fixed.

FIG. 2 shows that when a jam occurs downstream of the copy processing section (3), the transfer paper being conveyed upstream of the copy processing section (3) is branched by a transfer paper branching claw (6), and the transfer paper is transported. A block showing a processing circuit that performs a series of processing in which the transfer paper is introduced into the intermediate tray (54) through the section (7), and after the jam is cleared, the paper is fed by the paper feed roller (53) when forming an image again. It is a diagram.

The processing circuits are CPU (90) and CPU (90).
Transfer paper detection switch (94) connected to the input side of (
95), sorter B), a reset switch (93) that is operated at the end of jam processing, a branch solenoid (9 [f)] connected to the output side of the CPU (90), a paper feed clutch (97), It is composed of transport latches (98) to (101). Branch solenoid (9B) is CPU
The position of the transfer paper branching claw (6) is switched based on the command signal (90).

The paper feed clutch (97) rotates the paper feed roller (53) in order to send out the transfer paper remaining on the intermediate tray (54). Furthermore, a conveyance latch (98) represents a clutch that drives the conveyance rollers (511) and (59), respectively, in order to guide the transfer paper sent out from the intermediate tray (54) to the copy processing section (3). (99) is a conveyance roller (72) (7) provided in the transfer paper conveyance section (7).
4), and the conveyance latch (100) drives the paper feed rollers (41a) to (41c), respectively.
The transport latches (101) represent clutches that respectively drive the registration rollers (43).

The control procedure by the CP U (90) will be explained below.

When using the RA D F (12) to feed multiple originals one by one and pull out multiple sheets of transfer paper corresponding to each original to make multiple copies, the multiple sheets of transfer paper must be It is taken out from the paper feed cassette (13a) or (13b), subjected to copy processing in the copy processing section (3), fixed processing by the fixing device (4B), and then transferred to the paper ejection roller (48).
) and is automatically sorted by sorter S). For example, suppose that a conveyance jam occurs between the copy processing section (3) and the paper ejection roller (48) during this series of steps. This jam can be determined, for example, by the CPU (90) not being able to detect that the transfer paper detection switch (95) was turned on within a predetermined time from the time when the transfer paper detection switch (94) was turned on. In this case, since the transfer paper is continuously fed at high speed from the document feed cassette (41a) or (41b), the transfer paper is continuously fed from the document feed cassette (t3a).
Alternatively, it can be assumed that one or more sheets of transfer paper are being transported during the transport path from (13b) to the copy processing section (3). Therefore, the CPU (90) controls the drive of the transport latch (101) and the registration roller (43).
) continue to rotate (paper feed rollers (41a) (41b)
, conveyor belt (45), conveyor roller (47) (48)
(5(i) (57), sorter (8), etc. are of course stopped for jam removal).

Furthermore, in order to branch the transfer paper being conveyed, the branch solenoid (96) is driven to move the transfer paper branch claw (6), and the conveyance latch (99) is driven to move the transfer paper conveyance unit ( 7) rotate the conveyance rollers (72) and (74) provided therein. As a result, the transfer paper that was being conveyed from the downstream side of the document feed cassette (13a) or (13b) to the registration roller (43) is moved to the transfer paper branching claw (6).
The paper enters the transfer paper conveying section (7) from there and is accumulated on the intermediate tray (54). After this, the driving of the branch solenoid (9G) and the transport latches (99) and (101) is stopped.

When the jam is cleared and the reset switch (93) is operated, the copying machine returns to its original copyable state. Then, when a copy button (not shown) is pressed, exposure of the original starts, but the CPU (90) is not activated by the transport latch (1).
00), but instead, the paper feed clutch (97
), drives the transport latch (9B).

As a result, the document feed cassettes (13a) and (13b)
The transfer paper in the intermediate tray (54) is pulled out by the paper feed roller (53) and passes through the transfer paper conveyance path (55) to the registration roller (43) without being taken out. transported. Thereafter, the registration roller (43) is driven to rotate in synchronization with the rotation of the photosensitive drum (31) to which the toner image is attached, and a copying process is performed on the transfer paper.

As described above, if a transfer paper jam occurs downstream of the copy processing section (3), the transfer paper that is being transported upstream of the copy processing section (3) is moved by the transfer paper branching claw (3). The transfer paper contained in the original paper feed cassette (13a) or (13b) is introduced into the intermediate tray (54) through the transfer paper conveying section (7), and after the jam is cleared, when copying again. The transfer paper can be reused by feeding the transfer paper in advance.

In addition, in the above embodiment, even if a jam occurs in the two-wheel drive, similar processing can be performed. Furthermore, the invention is not limited to the case where the RA D F (12) is used, but can also be applied, for example, when setting a plurality of copies to obtain a plurality of copies of the same document.

Furthermore, in the above process, the following changes are also possible. That is, in the above process, the transfer paper that was being conveyed from the downstream side of the document feed cassette (13a) or (13b) to the registration roller (43) when the jam occurred is continued to be conveyed, and the transfer paper branching claw ( 6), the paper enters the transfer paper conveying section (7) and is accumulated on the intermediate tray (54). However, after a jam occurs, all conveyance is stopped and the jam is cleared, and only the transfer paper at the location where the jam occurs is taken out. (after operating the copy button), original paper feed cassette (13a) or (
The transfer paper remaining on the conveyance path from downstream of the registration roller (43) to the intermediate tray (5) is conveyed.
4). In other words, the process of conveying the remaining transfer paper to the intermediate tray (54) can be carried out at any time after the jam occurs and before the next copying operation begins. .

Next, a second embodiment will be described using FIG. 3. Like the image forming apparatus shown in FIG. 1, the image forming apparatus shown in FIG.
Although this is a copying machine equipped with an automatic transfer paper distribution function, the major difference from the image forming apparatus shown in FIG. Therefore, the structure is not different from that of a normal duplex image forming copying machine.

However, in the image forming apparatus described above, the processing procedure performed when a jam occurs downstream of the switching claw (49) is different.

FIG. 4 shows that when the above-mentioned jam occurs, the image processing section (3) is
The transfer paper that is in the middle of the conveyance path leading to the paper is passed through the image processing section (3) without image formation, is introduced to the intermediate tray (54) via the switching pawl 49), and after the jam is cleared, is transferred again. A processing circuit that performs a series of processes for feeding transfer paper from an intermediate tray (54) when forming an image is shown.

The processing circuit in FIG. 4 includes a CPU (90) and a CPU (90).
Transfer paper detection switch (90) connected to the input side of (90)
5), a sorter (8), a reset switch (93) operated at the end of jam processing, a charger (32) connected to the output side of the CPU (90), a developing device (33), and a transfer charger. (34), branch solenoid (
102), paper feed clutch (97), transport latch (1
00), (101), and (103). As mentioned above, the transport latches (100) (101) are connected to the paper feed rollers (41a) to (4Lc) and the registration rollers (
43) respectively.

The conveyance latch (103) is connected to the conveyance roller (44) (4
G) (47), conveyor belt (45), conveyor roller (5)
This is a clutch that drives B). Also, a charging charger (32), a developing device (33), a transfer charger (34)
The respective potentials are controlled by the CPU (90). Moreover, the branch solenoid (102)
The position of the switching claw (49) is switched based on the command signal (90). The paper feed clutch (97) rotates the paper feed roller (53) in order to send out the transfer paper remaining on the intermediate tray (54) as described above.

The control procedure by the CP U (90) will be explained below.

A single document placed on the contact glass (11) or when using RADF (12), the RADF
In order to perform copy processing on each original supplied from (12), multiple sheets of transfer paper are successively taken out from the paper feed cassette (13a) or <13b), and the copy processing section (3)
During a series of processes in which the paper is copied at the printer, the fixing device (4B) performs the fixing process, the paper is ejected through the paper ejection roller (48), and the paper is automatically sorted by the sorter B), a conveyance jam occurs, for example, at the two-tall printer. Suppose we did. Sorter [
F]), it can be assumed that the transfer paper is being conveyed even in the middle of the conveyance path from the document feed cassette (13a) or (13b) to the switching claw (49). Therefore, the CPU (90) uses the transport latch (
101) and (103) continue to drive the registration rollers (101) and (103).
43), conveyor belt (45), conveyor rollers (44) (4
7) Continue to drive (5B) (paper feed roller (41a)
(41b), the discharge roller (48), and the sorter (8) are stopped for jam removal). Then, the branch solenoid (102) is driven to switch the transfer paper being conveyed to the switching claw (49).
). At the same time, the CPU (90) controls the potential of the charger (32) to stop charging the surface of the photoreceptor drum (31), and controls the potential of the developing device (33) to suppress adsorption of toner particles. Then, the potential of the transfer charger (34) is controlled to suppress the first toner particles from landing on the transfer paper. As a result, the document feed cassette (13
The transfer paper that has been conveyed along the conveyance path from downstream of a) or (13b) to the conveyance roller (44) is transferred to the copy processing section (3).
The copying processing section (3) without any image being formed in
, passes through the fixing device (46), enters the feedback transfer paper conveying section (4a), and is accumulated on the intermediate tray (54). After this, transport latches (101), (103),
And the driving of the branch solenoid (102) is stopped.

After this, the jam is cleared and the reset switch (93
) is operated, the copying machine returns to the original copy-enabled state. Then, when the copy button (not shown) is pressed, the exposure of the original starts, but the CPU (90)
instead of driving the paper feed clutch (9
7) Drive. This allows the document feed cassette (13
The transfer paper contained in a) or (13b) is not taken out, but the transfer paper contained in the intermediate tray (54) is pulled out by the paper feed roller (53) and continues along the transfer paper conveyance path (55). and is conveyed to the registration rollers (43). Thereafter, the photoreceptor drum (31) to which the toner image is attached
) is rotated in synchronization with the rotation of the register roller (43), and a copying process is performed on the transfer paper.

As described above, if a transfer paper jam occurs in the sorter [F]), the transfer paper being conveyed upstream of the copy processing section (3) can be transferred without forming an image on the copy processing section (3).
) and guide it to the switching claw (49).
), the transfer paper is introduced into the intermediate tray (54) through the transfer paper transport path (4a), and after the jam is cleared, when copying again, the document feed cassette (13a) or (13b)
) By feeding this transfer paper before the transfer paper contained in the paper, we aim to reuse the transfer paper.

In addition, in the above procedure, in order not to form an image on the transfer paper being transported, the CPU (90) uses the charger (3).
2), the potentials of all of the developing device (33) and transfer charger (34) are controlled, but it goes without saying that the potential of only one or two of them may be controlled. In addition, in the above embodiment, it is assumed that a conveyance jam occurs in the sorter [F], but the present invention is not limited to this.
It is also possible to assume that a general transfer paper jam occurs downstream of the switching claw (49). For example, if the transfer paper detection switch (95) provided on the paper ejection roller (48) detects the leading edge of the transfer paper, it does not detect that the trailing edge of the transfer paper has passed even after a certain period of time has elapsed. , it is sufficient to assume that a jam has occurred and apply the above procedure.

In addition, in the configuration shown in FIG. 3 above, the switching claw (49) is
It may be provided between the copy processing section (3) and the fixing device (46). In this case, the transfer paper that has passed through the copy processing section G) without image formation is guided to the intermediate tray (54) without passing through the fixing device (4B), so the transfer paper is not heated and the transfer It prevents the paper from stretching or warping, and when it is copied again, a beautiful and accurate image can be obtained.

Additionally, the process of transporting the transfer paper remaining in the machine and guiding it to the intermediate tray (54) can be carried out at any time after the jam occurs and before the next copying operation begins. This is the same as explained in the embodiments of FIGS. 1 and 2.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and can be applied to laser printers, for example. Various design changes can be made without changing the gist of the invention.

<Effects of the Invention> As described above, according to the present invention, a branch part is provided in the middle of the transport path from the downstream of the paper feeding part to the image forming processing part, and a paper transport part is provided from this branch part to the intermediate tray. According to the image forming apparatus, when a paper transport jam occurs downstream of the image forming processing section, the paper is transported upstream of the image forming processing section, is branched from the branching section, and then The paper can be reused by introducing the paper into the tray, removing the jam, and then feeding the paper when forming an image again.

In addition, even if the above-mentioned branching section and paper transport section are not provided, if a paper transport jam occurs, the paper being transported along the transport path is allowed to pass through the image forming processing section without any image formation. The paper can be reused by guiding the paper to the intermediate tray and feeding it when forming an image again after clearing the jam.

Therefore, in any case, image formation can be performed by reusing paper that could not be used after jam removal in the past, thereby eliminating waste of paper and increasing economic efficiency.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram illustrating the internal mechanism of a copying machine equipped with an automatic double-sided copying function. Figure 2 is a schematic diagram illustrating the internal mechanism of a copying machine equipped with an automatic double-sided copying function. A block diagram showing a processing circuit that performs a series of processes to introduce the paper into the intermediate tray and feed the paper when forming an image again. FIG. FIG. 4 is a schematic diagram illustrating the internal mechanism. When a paper jam occurs, the paper that is in the middle of the conveyance path is passed through the copying processing section and introduced to the intermediate tray without image formation, and when the image is formed again. FIG. 2 is a block diagram showing a processing circuit that performs a series of processes for feeding the paper.

Claims (1)

[Claims] In an image forming apparatus equipped with an intermediate tray that temporarily stores paper on which an image has been formed once and supplies it to the image forming processing section again, the image forming apparatus extends from downstream of the paper feeding section to the image forming processing section. a branch part provided in the middle of the transport path, a paper transport part that transports the paper branched from the branch part to an intermediate tray, and a detection means that detects that a paper transport jam has occurred downstream of the image forming processing part; After receiving the detection signal from the detection means, a conveyance path driving means drives a paper conveyance path from downstream of the paper feeding section to the intermediate tray via a branching section, and a branching means for diverting unimaged paper being conveyed. An image forming apparatus characterized by having a branching part driving means for operating the section, and a paper feeding means for feeding the paper introduced into the intermediate tray in order to convey the paper to the image forming processing section when forming an image again. Device. 2. In an image forming apparatus capable of conveying a sheet on which an image has been formed once to an intermediate tray through a branching section and performing the image forming process again, a detection means for detecting that a paper conveyance jam has occurred downstream from the branching section. and, after receiving the detection signal from the detection means, a conveyance path driving means for driving a conveyance path from downstream of the paper feeding section to the image forming processing section, passing through the branching section to the intermediate tray, and the image forming processing section. The image forming apparatus includes an image forming stopping means for stopping image forming processing on the passing paper, and a paper feeding means for feeding the paper introduced into the intermediate tray to be conveyed to the image forming processing section when forming an image again. An image forming apparatus characterized by: