JP2000086044A - Sheet temporarily holding device and image forming device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet temporarily holding device (paper ejecting option) easily processing a jam of even a small size sheet particularly and an image forming device using it. SOLUTION: In a paper ejecting option 3, two available access passages for a sheet are arranged on the upper face of a sheet guide 32 and below an inner frame 36, and a switching member 33 switching these two access passages for use is arranged. When a sheet to be fed again is discharged, a state of the switching member 33 is switched according to the sheet size. That is, a sheet shorter than a predetermined length L is fed again after temporarily held on the upper face of the sheet guide 32, while a sheet longer than the predetermined length L is fed again after temporarily held in a clearance between the lower side of the inner frame 36 and a device body 2. In case of a paper jam in the device body 2, a shorter sheet can be removed from an openable cover 31 by opening, while a longer sheet can be removed by pulling out its tip, which is protruded from a B position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temporary sheet holding device provided in a paper discharge system of an image forming apparatus. More specifically, the present invention relates to a sheet temporary holding device that can temporarily hold a sheet discharged from an image forming apparatus for re-feeding the sheet to the image forming apparatus, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a sheet (print paper or O
An HP sheet or the like is returned to the image forming unit to perform double-sided printing or composite printing. In such an image forming apparatus, generally, as shown in FIG.
When the vicinity of the rear end of the sheet P on which the image has been formed for the second time reaches the discharge roller pair 102 provided immediately before the discharge port 101, the discharge roller pair 102 is rotated in the reverse direction to rotate the sheet P.
Is drawn into the re-feeding path. Therefore,
The sheet P on which double-sided printing or the like is performed has its leading end once projecting from the discharge port 101 onto the discharge tray 103 after the first image formation.

Further, a finisher device for collating and grouping sheets after image formation may be attached to the image forming apparatus as a retrofit. FIG.
When the finisher device is retrofitted to the image forming apparatus as shown in FIG. 5, the finisher device 104 is mounted on the paper discharge tray 103 as shown in FIG. The finisher device 104 has a shift tray 105 that can be slid horizontally (in a direction perpendicular to the paper surface of FIG. 16), and copes with collation processing and grouping depending on the slide position. Such a post-installed finisher device is hereinafter referred to as a “paper ejection option”.

[0004]

However, the above-mentioned prior art has the following problems. That is, the image forming apparatus sometimes stops the operation due to a sheet jam. In such a case, it is necessary to restart after removing the sheet in process. However, when the paper ejection option 104 is attached, it may be difficult to clear the jam. That is, if a jam occurs in a state where the sheet after the first image formation is temporarily projected from the sheet discharge port 101 as shown in FIG. 15, the sheet discharge option 104 hinders the removal of the sheet. In particular, in the case of a small-sized sheet, the difficulty is remarkable because the leading end does not come out of the paper ejection option 104.

The present invention has been made to solve the above-mentioned conventional problems. That is, it is an object of the present invention to provide a temporary sheet holding device capable of easily performing jam processing even for a sheet having a particularly small size, and an image forming apparatus using the same.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems.
A first path temporarily held to reversely convey the sheet conveyed into the apparatus body and a second path different from the first path, and sheet conveyance and holding are performed by either the first path or the second path. Switching means for switching between the two. The sheet temporary holding device is used by being attached near the paper discharge port of the image forming apparatus as a paper discharge option. In this case, the sheet discharged from the image forming apparatus is
Depending on the state of the switching means, it proceeds to one of the first path and the second path and is temporarily held for reverse transport.

In a preferred embodiment of the sheet holding device, an opening / closing cover is provided at a position where the first path is located inside the body and is a part of the body and faces the first path. That is. Further, the second path is located in a gap between the machine body and the image forming apparatus main body. In this case, when the switching unit is oriented in the second path, the sheet discharged from the image forming apparatus proceeds to a gap between the machine body and the image forming apparatus main body. When the sheet is to be re-fed, the sheet is temporarily held in a gap between the machine body and the image forming apparatus main body until the sheet is pulled into the image forming apparatus. If a jam occurs in this situation, if the leading end of the sheet protrudes from the gap between the machine body and the image forming apparatus main body, the leading end can be removed by hand.

[0008] If the length of the sheet discharged from the image forming apparatus is not sufficient, the switching means may be set in a state facing the first path. In this case, the sheet discharged from the image forming apparatus proceeds to the first path.
When the sheet is to be re-fed, the sheet is temporarily held in the first path until it is pulled into the image forming apparatus. If a jam occurs in this situation, the sheet can be removed by pulling the sheet by hand by opening the open / close cover.

Furthermore, in this sheet temporary holding device, the first
Is a part of a path for finally discharging the sheet, and it is preferable that a pair of conveying rollers is provided downstream of the first path. When the sheet discharged from the image forming apparatus is not to be re-fed, the switching unit may be set to the state of the first path, and the pair of conveying rollers may be rotated forward. As a result, the sheet is guided to the first path to reach the pair of transport rollers, driven by the pair of transport rollers, and finally discharged.

When the sheet to be re-fed is temporarily held on the first path, the switching means is set to face the first path, and the conveying roller pair is stopped or reversely rotated. It is good. As a result, the leading end of the sheet is prevented from being pinched by the pair of conveying rollers, and refeeding is performed smoothly.

The image forming apparatus according to the present invention includes a sheet temporary holding device, an image forming section for forming an image on a sheet, and a discharge roller pair for guiding a sheet passing through the image forming section to the sheet temporary holding device. A sheet re-feeding path for re-feeding the sheet from the sheet discharge roller pair to the image forming unit; a sheet length detecting unit for detecting a length of the sheet passing through the image forming unit in a traveling direction; When the paper discharge roller pair is rotated forward when the paper is discharged from the printer to the sheet temporary holding device,
If the sheet is to be re-fed, the sheet has passed through the image forming unit, and a discharge roller pair control unit that reverses the sheet discharge roller pair before the rear end of the sheet passes through the sheet discharge roller pair. If the sheet is to be re-fed and the length in the traveling direction is equal to or longer than a predetermined length, the switching means is switched to the second one.
And a switching control means for setting the switching means to the state of the first path in other cases.

In this image forming apparatus, if a sheet subjected to image formation in the image forming section is not to be re-fed, the discharge roller pair is rotated forward by the discharge roller pair control means, and switching is performed. The switching means is set to the inward state by the control means. As a result, the sheet is guided to the first path while being driven by the sheet discharging roller pair, and is finally discharged.

If the sheet subjected to image formation in the image forming section is to be fed again, the length of the sheet in the traveling direction is detected by the sheet length detecting means.
The following control is performed according to the detection result. That is, if the length is longer than the specified length,
The discharge roller pair is rotated forward by the discharge roller pair control means, and the switching means is set to the outward state by the switching control means. As a result, the sheet is driven by the pair of paper discharge rollers and advances to the gap between the machine body and the image forming apparatus main body. Then, before the trailing end of the sheet passes through the discharge roller pair, the discharge roller pair is reversely rotated by the discharge roller pair control means. As a result, the sheet is guided to the re-feeding path, and is again used for image formation in the image forming unit. Here, the sheet is temporarily held in a gap between the machine body and the image forming apparatus main body before being re-fed. If a jam occurs in this situation, if the leading end of the sheet protrudes from the gap between the apparatus body and the image forming apparatus main body, the leading end can be removed by hand.

On the other hand, if the length of the sheet is less than the predetermined length, the discharge roller pair is rotated forward by the discharge roller pair control means, and the switching means is set to the inward state by the switching control means. Is done. As a result, the sheet is driven by the discharge roller pair and advances to the first path.
Then, before the trailing end of the sheet passes through the discharge roller pair, the discharge roller pair is reversely rotated by the discharge roller pair control means. As a result, the sheet is guided to the re-feeding path, and is again used for image formation in the image forming unit. Here, the sheet is temporarily held in the first path before being re-fed. If a jam occurs in this situation, if the body is provided with an openable cover, the sheet can be pulled and removed by hand by opening the cover.

In the image forming apparatus, when the sheet passing through the image forming section is to be re-fed and the length of the sheet in the traveling direction is less than a predetermined length, the conveying roller pair is stopped or reversed. It is preferable to have a transport roller pair control unit that rotates the transport roller pair and rotates the transport roller pair forward when the sheet does not refeed. In this case, if the sheet that has been subjected to image formation in the image forming unit is not to be re-fed, the transport roller pair control unit rotates the transport roller pair forward. This is for driving the sheet toward final discharge. When the sheet is to be re-fed and the length in the traveling direction is less than the predetermined length, the conveying roller pair is stopped or reversely rotated by the conveying roller pair control means. This is to prevent the leading end of the sheet from being pinched by the pair of conveying rollers.

Alternatively, the image forming apparatus includes the above-described temporary sheet holding device, an image forming section for forming an image on a sheet, a discharge roller pair for guiding the sheet passing through the image forming section to the temporary sheet holding device, and a discharging roller. The sheet re-feeding path for re-feeding the sheet from the pair of paper rollers to the image forming section, and the switching means are oriented in the first path, and the sheet discharging roller pair and the conveying roller pair are rotated forward to thereby cause the sheet to rotate. The second paper discharging control means for discharging paper without re-feeding paper and the switching means
The first re-feeding operation is performed by reversing the discharge roller pair before the trailing edge of the sheet passes through the sheet in the direction of the path, and re-feeding the sheet whose length in the traveling direction is equal to or longer than a predetermined length. The length in the traveling direction is less than the predetermined length by setting the paper control unit and the switching unit in the state of the first path and rotating the pair of paper discharge rollers in reverse before the trailing edge of the sheet passes. The same applies to a case having a second sheet re-feeding control means for re-feeding a sheet. Here, it is more preferable that the second sheet re-feed control unit stops or reversely rotates the pair of transport rollers.

In this image forming apparatus, the predetermined length is set before the trailing edge of the sheet advanced to the second path by the switching means for the orientation of the second path passes through the discharge roller pair. It is preferable that the tip has a length that protrudes from a gap between the machine body and the image forming apparatus main body. In this case, an appropriate traveling path is selected in accordance with the length of the sheet to be re-fed, and there is no trouble in jam processing.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment has a main body 2 and a paper discharge option 3 mounted on a paper discharge position 91 thereof. The main body 2 includes a paper feeding system 92,
The image forming unit 95 includes a photosensitive drum 93 and a transfer unit 94, and a sheet re-feed unit 96 that sends a sheet once subjected to image formation to the image forming unit 95 again.
A sheet sensor 40 for detecting the length of the sheet in the traveling direction is provided between the sheet feeding system 92 and the image forming unit 95. The paper discharge option 3 has a shift tray 97 as a final destination of the sheet discharged from the main body 2.

Paper discharge option 3 in image forming apparatus 1
FIG. 2 shows the internal structure of the device and its surroundings. The paper discharge option 3 has an outer shape formed by a substantially rectangular parallelepiped outer plate body 30. An opening / closing cover 31 is provided in a part of the outer shape of the paper discharge option 3 and at one upper right corner in FIG. The opening / closing cover 31 can be manually opened as shown in FIG. In the state of FIG. 3 in which the opening / closing cover 31 is opened, the inside of the paper discharge option 3 can be seen from the right side in the figure as indicated by the arrow A. Further, the operator can manually access the inside of the paper discharge option 3.

A sheet guide 32 is provided inside the paper discharge option 3. The sheet guide 32 is attached to the main body 2.
Is a member for guiding the sheet discharged from the printer to the shift tray 97. At the lower right of the sheet guide 32 in the figure, a switching member 33 having a substantially triangular shape is provided. The switching member 33 is rotatable about a support shaft 34, and the first switching member 33 shown in FIG.
(Inbound state) and the second state in FIG. 4 (outbound state). At the upper left of the sheet guide 32 in the drawing, a pair of conveying rollers 35 is provided. The transport roller pair 35 has a role of driving the sheet on the sheet guide 32 toward the shift tray 97 by rotating forward. The image forming unit 95
It is also possible to rotate in the reverse direction so as not to pinch the sheet to be re-fed.

An inner frame 36 is provided inside the paper discharge option 3. The inner frame 36 is provided with a motor 37 as a drive source of the transport roller pair 35 and a solenoid 38 as a drive source of the switching member 33. The motor 37 and the solenoid 38 are controlled from the main body 2.

Below the inner frame 36, the main body 2 is provided.
Of paper discharge trays 21 are located. Inner frame 3
6 and the paper discharge tray 21, there is a gap through which the sheet can advance. The position indicated by the arrow B at the left end in FIG. 2 is open, and the leading end of the sheet can protrude from here.

In the main body 2, a discharge port 22 is formed at a position facing the switching member 33 of the discharge option 3. Immediately inside, a pair of discharge rollers 23
Is provided. The discharge roller pair 23 is provided in the image forming section 9.
5 has a role of discharging the sheet provided for image formation from the discharge port 22 to the discharge option 3 by rotating forward. Further, the sheet has a role of being drawn into the re-feeding unit 96 by rotating the sheet in the reverse direction. Further, a sheet sensor 24 for detecting the presence or absence of a sheet is provided further inside the sheet discharge roller pair 23. The sheet sensor 24 is a sensor of a transmission light system, and is located on a path from the image forming unit 95 to the sheet discharge roller pair 23.

Next, a control system of the image forming apparatus 1 will be described. This control system is configured as shown in the block diagram of FIG. That is, the control unit 25 of the image forming apparatus 1
Are mainly configured with an engine control unit 26. Various signals are input to the engine control unit 26 from each unit of the image forming apparatus 1, such as a sheet discharge signal indicating whether or not a sheet is discharged and a size signal for knowing the size of the discharged sheet. The engine control unit 26 controls the image forming apparatus 1
The main body 2 includes a paper feed signal for instructing a sheet supply from the paper feed system 92, a print output signal for controlling image formation in the image forming unit 95, a main motor signal, and rotation of the discharge roller pair 23. Various signals, such as a paper ejection drive signal, are output. Various signals such as a path switching signal for controlling the state of the switching member 33, a transport drive signal for controlling the rotation of the pair of transport rollers 35, and a shift signal for instructing the movement of the shift tray 97 are also transmitted to each section of the paper discharge option 3. Is output.

Further, the engine control unit 26 is connected to an operation display panel 28 via a controller 27. As a result, the operator can operate the image forming apparatus 1 or recognize the operation status thereof. The engine control unit 26 is also connected to a host 29 such as a personal computer. As a result, it is possible to receive image data and other signals from the host 29, and to send a display signal such as status to the host 29.

Next, the operation of the image forming apparatus 1 having the above configuration and control system will be described. The basic operation of the image forming apparatus 1 is as follows. An image is formed on the sheet taken out from the sheet feeding system 92 by the image forming unit 95, and the sheet is finally discharged onto the shift tray 97 of the discharge option 3. That is. In the image forming apparatus 1, the sheet once subjected to image formation in the image forming unit 95 may be re-fed to the image forming unit 95 via the re-feeding unit 96 to perform double-sided printing or composite printing. it can. In this case, the sheet on which the image has been formed is temporarily held by the paper discharge option 3 and sent back to the main body 2 of the image forming apparatus 1. The control by the engine control unit 26 for this series of operations will be described with reference to the flowcharts of FIGS.

The flowchart of FIG.
This is the main routine. That is, when the power of the image forming apparatus 1 is turned on, an initial setting is first performed (# 1).
Next, input / output processing is performed (# 2). I / O processing is
The processing includes input / output of signals to / from each unit of the image forming apparatus 1 and operations associated therewith. The contents will be described later with reference to FIG. Subsequently, a paper feeding process is performed (# 3). That is, if it is a timing to feed a new sheet to the image forming unit 95, one new sheet is supplied from the sheet feeding system 92. Alternatively, if it is a timing to pass a sheet to receive the second print to the image forming unit 95, the sheet staying in the re-feeding unit 96 is sent to the image forming unit 95.

Then, an image forming process is performed (#
4). This processing includes exposure of the photosensitive drum 93 based on image data, development, transfer, fixing, and the like.
Next, a paper discharge / storage process is performed (# 5). The content of this processing is the control of the paper discharge roller pair 23, which will be described later with reference to FIG. Subsequently, control of the paper discharge option 3 is performed (# 6). The contents will be described later with reference to FIGS. When other processing other than the above is performed (#
7), the process returns to # 2 after the internal timer expires (# 8).
Thereafter, the processes of # 2 to # 8 are repeated, and a series of printing operations are executed.

Next, the contents of the input / output processing of # 2 in FIG.
This will be described with reference to FIG. In the input / output processing, first, various sensor signals input from each unit of the image forming apparatus 1 are acquired (# 11). The signals acquired here include input signals from the sheet sensor 24 and the sheet sensor 40. The acquired signal is stored in the built-in RAM of the engine control unit 26. Subsequently, a command signal or the like is output to each unit of the image forming apparatus 1 (# 12).

Then, the size of the sheet passing through the image forming section 95 in the traveling direction is calculated (# 1).
3). This calculation is based on the time required for the sheet to pass through the sheet sensor 40. That is, as shown in FIG. 11, the time T from the on edge to the off edge of the output signal of the sheet sensor 40 is obtained. This is divided by the system speed of the image forming apparatus 1 to calculate the size. The calculated size is stored in the built-in RAM of the engine control unit 26. Subsequently, each part of the image forming apparatus 1 (the paper feeding system 92, the paper re-feeding unit 96, the paper discharging option 3
The presence / absence of sheets on the inside of the shift tray 97) is confirmed (# 14), and other input / output operations are performed (# 15), and the process returns to the main routine of FIG.

Next, the contents of the paper discharging / storing process # 5 in FIG. 6 will be described with reference to FIG. In the paper discharge / storage process, first, it is determined whether or not the forward rotation timer, which is one of the built-in timers of the engine control unit 26, has expired (# 2).
1). The forward rotation timer is a timer for rotating the discharge roller pair 23 forward for a predetermined time when a sheet passes through the image forming unit 95, and is set in # 28 described later. If the forward rotation timer has not yet expired (# 21: No), in step # 22, the discharge roller pair 23
Is rotated forward, and then proceeds to # 23. If the forward rotation timer has expired (# 21: Yes), the flow directly goes to # 23, bypassing # 22.

Next, it is determined whether the reverse rotation timer, which is also one of the built-in timers of the engine control unit 26, has expired (# 23). The reverse rotation timer is once
This is a timer for reversely rotating the sheet discharge roller pair 23 for a predetermined time in order to draw the sheet projecting from the sheet 2 and re-fed into the re-feed unit 96.
The reverse rotation timer is set in # 31 described later. If the reverse rotation timer has not yet expired (# 23: N
o) After the paper discharge roller pair 23 is rotated in reverse at # 24,
Proceed to 25. If the reverse rotation timer has expired (#
23: Yes), bypassing # 24 and proceeding directly to # 25.

Next, it is determined whether the stop timer, which is also one of the built-in timers of the engine control unit 26, has expired (# 25). The stop timer is a timer for stopping the discharge roller 23 for a predetermined time from completely discharging the sheet that is not fed again to the discharge option 3 until the next sheet reaches the discharge roller 23. The stop timer is set in # 32 described later. If the stop timer has not expired yet (# 25: No), the discharge roller pair 23 is forcibly stopped in # 26, and the process proceeds to # 27. If the stop timer has expired (# 25: Yes),
Proceeding directly to # 27, bypassing # 26.

Subsequently, it is determined whether or not the output of the sheet sensor 24 has changed from off to on (# 27). That is, if the leading edge of the sheet reaches the sheet sensor 24 and the output has an on-edge (see FIG. 11) between the previous control cycle and the current control cycle, it is determined to be Yes. If the determination is Yes, the forward rotation timer is set. Then, the process proceeds to # 28. No in # 27
If it is determined that # 2 is bypassed, # 2 is bypassed directly to # 2
Proceed to 8.

Then, it is determined whether or not the output of the sheet sensor 24 has changed from ON to OFF (# 29). That is, when the rear end of the sheet reaches the sheet sensor 24 and the output has an off-edge (see FIG. 11) between the previous control cycle and the current control cycle, it is determined as Yes. If No is determined here,
The storing process ends and the process returns to the main routine.

If the determination in # 29 is Yes, it is determined whether the sheet is to be stored in the re-feed unit 96, that is, whether the sheet is a sheet to be re-feeded (#). 30). If the sheet is to be re-fed (# 30: Yes), the reverse rotation timer is set, and the timing is started (# 31). Here, the time measured immediately before the trailing edge of the sheet is the discharge roller pair 23.
It is time to reach. If No is determined in # 30, the stop timer is set, and the time measurement is started (# 32). The clocking time in this case is a time required for the trailing edge of the sheet to completely pass through the discharge roller pair 23. After # 30 or # 31, the paper discharge / storage process ends, and the process returns to the main routine.

Next, the contents of control of the paper discharge option 3 of # 6 in FIG. 6 will be described with reference to FIG. Paper ejection option 3
In this control, first, it is determined whether or not the paper discharge option 3 is mounted on the image forming apparatus 1 (# 41).
This is because the paper discharge option 3 is a post-installation product that is sold separately from the image forming apparatus 1 and may not be mounted. If it is not mounted (# 41: No), this subroutine is terminated and the process returns to the main routine. In the present embodiment, since the paper discharge option 3 is installed, it is determined to be Yes, and the process proceeds to # 42 and thereafter.

Then, control of the conveying roller pair 35 is performed (# 42). Specifically, according to the flag set in # 55 or # 56 in FIG.
Is driven or stopped. Then, the shift tray 97 is controlled (# 43). That is, the shift tray 97 is moved in accordance with the collation or grouping processing mode set by the operator.
Next, a path switching process is performed (# 44). As described later (FIG. 10), the content of the sheet ejection option 3 such as the switching member 33 is controlled in accordance with the handling and size of the sheet ejected from the main body 2 as described later (FIG. 10). Then, when other processing relating to the paper discharge option 3 is performed (# 45), the control of the paper discharge option 3 is terminated, and the process returns to the main routine.

Next, the contents of the route switching process of # 44 in FIG. 9 will be described with reference to FIG. In the path switching process, first, the output of the sheet sensor 24 of the main body 2 has been switched from on to off (hereinafter, referred to as “on edge”).
It is determined whether or not (# 51). If it is not the on-edge (# 51: No), it is not the timing to perform the path switching process, so this subroutine is terminated and the process returns to the main routine. If the output of the sheet sensor 24 is on-edge (# 51: Yes), it is determined whether or not the sheet is to be fed again (# 5).
2). This determination is the same as the determination of # 30 during the paper discharge / storage process in FIG. If the sheet is not to be re-fed (# 52: No), a request flag for rotating the transport roller pair 35 forward is set (# 56).
Then, the solenoid 38 is operated to switch the switching member 33.
Is set to the inward state (# 57).

If the sheet is to be fed again (# 52: Yes), the size of the sheet in the running direction is compared with a predetermined length L (# 53). The size of the seat in the traveling direction is the size calculated in the seat size calculation process (# 13 in FIG. 7) of the input / output process (# 2 in FIG. 6). The predetermined length L of the sheet protruding from the paper feed port 22 of the main body 2 and entering the lower side of the switching member 33 of the paper discharge option 3 is not changed before the sheet completely escapes from the paper discharge roller pair 23. This is the length required to bring out the face from position B in 2. The value is based on the built-in RO of the engine control unit 26.
M is prepared in advance.

If the size of the sheet is smaller than the length L (# 53: No), a request flag for stopping the conveying roller pair 35 is set (# 55). Then, the solenoid 38 is operated to bring the switching member 33 into the inward state (# 57). If the size of the sheet is equal to or greater than the length L (# 53: Yes), the solenoid 38 is operated and the switching member 33 is set to the outward state (# 54). When the switching member 33 is operated in # 54 or # 57, the route switching process is terminated and the process returns to the main routine. The above is the control processing of the image forming apparatus 1 by the engine control unit 26.

Next, a description will be given of how the sheet that has passed through the image forming unit 95 receives with the paper discharge option 3. For this handling, the sheet to be re-fed is shorter than the predetermined length L, the sheet to be re-fed is longer than the predetermined length L, and the shift tray 97 is not fed again. There are three types of sheets that are finally discharged.

First, the handling of a re-feeded sheet shorter than the predetermined length L will be described. When such a sheet is discharged, the determination of # 52: Yes and # 53: No is made in the flow of FIG.
Therefore, the conveying roller pair 35 is stopped (# 55,
In step # 42 of FIG. 9, the switching member 33 is set to the inward state (# 57). Therefore, as shown in FIG. 12, the sheet P that has entered the discharge option 3 from the discharge port 22 by the forward rotation of the discharge roller pair 23 (# 22 in FIG. Guided to the top. At this time, since the transport roller pair 35 is stopped, the leading end of the sheet P is not pinched by the transport roller pair 35.

Then, immediately before the trailing end of the sheet P reaches the sheet discharge roller pair 23, the sheet discharge roller pair 23 rotates in the reverse direction, and the sheet P is drawn into the re-feed section 96. Thus, the sheet P is temporarily held by the sheet discharging option 3 and then stored in the sheet re-feeding unit 96.

Here, it is assumed that when the sheet P is in the vicinity of the position shown in FIG. 12, the sheet jam occurs in the main body 2 and the operation is stopped. In this case, the sheet P can be easily removed by hand if the open / close cover 31 is opened by hand as shown in FIG. Then, the image forming apparatus 1
Should be restarted.

Next, handling of a sheet to be re-fed and having a length equal to or longer than the predetermined length L will be described.
When such a sheet is discharged, the determination of # 52: Yes and # 53: Yes is made in the flow of FIG. Therefore, the switching member 33 is set to the outward state (# 54). Therefore, as shown in FIG. 13, the sheet P that has entered the paper discharge option 3 from the paper discharge port 22 by the forward rotation of the paper discharge roller pair 23 (# 22 in FIG. 8).
The lower surface of the switching member 33 allows the inner frame 3
6 and proceeds to a gap between the inner frame 36 and the paper discharge tray 21 of the main body 2.

When the sheet P reaches the discharge roller pair 23 immediately before the trailing edge of the sheet P, the leading edge of the sheet P always projects from the position B since the sheet P has a length equal to or greater than the predetermined length L. I have. Then, in the flow of FIG. 8, the determination of # 29: Yes and # 30: Yes is made. Therefore, the sheet discharging roller pair 23 rotates in the reverse direction, and the sheet P is drawn into the sheet re-feeding unit 96. Thus, the sheet P is temporarily held by the sheet discharging option 3 and then stored in the sheet re-feeding unit 96.

Here, it is assumed that when the sheet P is near the position shown in FIG. 13, the sheet jam occurs in the main body 2 and the operation is stopped. In this case, the user can easily remove the sheet P by hand without having to remove the paper discharge option 3 by grasping and pulling the leading end of the sheet P whose face is exposed from the position B. After that, the image forming apparatus 1 may be restarted.

Finally, the handling of sheets finally discharged to the shift tray 97 without refeeding will be described. When such a sheet is discharged, FIG.
In the flow of 0, the determination of # 52: No is made. Therefore, the conveying roller pair 35 is rotated forward (# 56,
In step # 42 of FIG. 9, the switching member 33 is set to the inward state (# 57). Therefore, as shown in FIG. 14, the sheet P that has entered the discharge option 3 from the discharge port 22 by the forward rotation of the discharge roller pair 23 (# 22 in FIG. Guided to the top. Then, the sheet is further conveyed by the forward rotation of the conveying roller pair 35 and finally discharged to the shift tray 97.

As described in detail above, according to the present embodiment, the sheet entrance path is provided in the paper discharge option 3 in two ways: the upper surface of the sheet guide 32 and the lower part of the inner frame 36. There is provided a switching member 33 for selectively using. When the sheet stored in the sheet re-feed unit 96 is discharged, the state of the switching member 33 is switched according to the length in the traveling direction. As a result, sheets shorter than the predetermined length L are temporarily held on the upper surface of the sheet guide 32 and then stored in the sheet re-feed unit 96. In this case, the transport roller pair 35 is stopped, so that the leading end of the sheet P is not pinched by the transport roller pair 35 and does not hinder storage. Further, even if the sheet jams in the main body 2 while the sheet is temporarily held, the sheet P can be easily removed by hand by opening the opening / closing cover 31 by hand.

A sheet having a length equal to or greater than the predetermined length L is temporarily held in a gap between the main body 2 below the inner frame 36 and then stored in the re-feeding section 96. Becomes For this reason, even if the sheet is jammed in the main body 2 while the sheet is temporarily held, the front end of the sheet P is exposed, and if the sheet is pinched by hand and pulled, the sheet is discharged. The sheet P can be easily removed by hand without removing the option 3 itself. Thus, regardless of the size of the sheet in the traveling direction, the image forming apparatus 1 with the paper discharge option 3 that can temporarily hold the sheet at an appropriate position before storage and does not hinder the jam processing can be provided. Provided.

The present embodiment is merely an example, and does not limit the present invention. Therefore, naturally, the present invention can be variously modified and modified without departing from the gist thereof. For example, when temporarily receiving a sheet shorter than the predetermined length L before storage, the conveying roller pair 35 is stopped in order to prevent the sheet from being pinched. At this time, the conveying roller pair 35 is rotated in reverse. It may be. Further, the present invention may be applied to a multi-stage discharge option having a large number of discharge trays. In this case, there are a plurality of sheet traveling paths when temporarily accepting a sheet shorter than the predetermined length L before storage.
The sheet re-feeding unit 96 has a function of turning a sheet upside down and performing double-sided printing.
May be provided with a function for returning to composite printing.
Further, the image forming unit 95 is not limited to the electrophotographic system,
Other systems such as an ink jet system may be used.

[0053]

As is apparent from the above description, according to the present invention, when a jam needs to be cleared while the sheet is temporarily held, the sheet temporary holding device can easily perform the jam processing regardless of the sheet size. , And an image forming apparatus using the same. In particular, a small-sized sheet can be easily jammed. In addition, there is no need to increase the size of the paper discharge option, which contributes to the compactness of the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall schematic configuration of an image forming apparatus with a paper discharge option according to an embodiment;

FIG. 2 is a diagram illustrating a configuration of a paper discharge option in FIG. 1;

FIG. 3 is a diagram illustrating a state in which an opening / closing cover of a paper discharge option is opened.

FIG. 4 is a view for explaining the movement of a switching member in a paper discharge option.

FIG. 5 is a control block diagram of the image forming apparatus.

FIG. 6 is a flowchart illustrating a main routine of the image forming apparatus.

FIG. 7 is a flowchart illustrating a subroutine of an input / output process.

FIG. 8 is a flowchart illustrating a subroutine of a paper discharge / storage process.

FIG. 9 is a flowchart illustrating a control routine of a paper discharge option.

FIG. 10 is a flowchart illustrating a subroutine of a path switching process.

FIG. 11 is a diagram illustrating an output of a sheet sensor.

FIG. 12 is a diagram illustrating a state where a short sheet is temporarily held.

FIG. 13 is a diagram illustrating a state where a long sheet is temporarily held.

FIG. 14 is a diagram illustrating a state in which a sheet is finally discharged.

FIG. 15 is a diagram illustrating sheet re-feeding in a conventional image forming apparatus (without a sheet discharge option).

FIG. 16 is a diagram illustrating a state in which a paper ejection option is mounted on a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body 3 Discharge option 23 Discharge roller pair 24 Sheet sensor 26 Engine control unit 30 Outer plate body 31 Opening / closing cover 32 Sheet guide 33 Switching member 35 Transport roller pair 95 Image forming unit 96 Re-feed unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshikazu Takesada 2-3-113 Azuchicho, Chuo-ku, Osaka City Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Akira Ohata 2-chome Azuchicho, Chuo-ku, Osaka City No. 13 Osaka International Building Minolta Co., Ltd. (72) Inventor Masaki Nakayama 2-3-1 Azuchicho, Chuo-ku, Osaka City Osaka International Building Minolta Co., Ltd. F-term (reference) 3F053 BA03 BA12 BA18 BA21 EA02 EA05 EB04 EC02 LA02 LA06 LB03 3F100 AA02 BA14 CA13 CA17 EA02

Claims (7)

[Claims] 1. A first path for temporarily holding a body and a sheet conveyed in the body for reverse conveyance, and a second path different from the first path and a first path for conveying and holding the sheet. And a switching unit for switching between the first path and the second path. 2. The sheet temporary holding device according to claim 1, wherein the first path forms a part of a path for finally discharging the sheet, and a conveying roller is provided downstream of the first path. A sheet temporary holding device comprising a pair. 3. A sheet temporary holding device according to claim 1 or 2, an image forming unit for forming an image on the sheet, and a sheet discharge guiding the sheet passing through the image forming unit to the sheet temporary holding device. A pair of rollers, a re-feed path for re-feeding a sheet from the pair of discharge rollers to the image forming unit,
Sheet length detecting means for detecting the length of the sheet passing through the image forming unit in the running direction, and rotating the discharge roller pair forward when the sheet is discharged from the image forming unit to the temporary sheet holding device. And, when the sheet is to be re-fed, a discharge roller pair control means for reversing the discharge roller pair before the trailing end of the sheet passes through the discharge roller pair; If the sheet that has passed the forming section is to be re-fed and the length of the sheet in the traveling direction is equal to or longer than a predetermined length, the switching unit is directed to the second path. An image forming apparatus comprising: a switching control unit that sets the switching unit in a state of a first path. 4. The image forming apparatus according to claim 3, wherein the sheet that has passed through the image forming unit is to be re-fed and the length of the sheet in the traveling direction is less than a predetermined length. An image forming apparatus comprising: a conveyance roller pair control unit that stops or reversely rotates a conveyance roller pair and, when the sheet does not refeed, rotates the conveyance roller pair forward. 5. A temporary sheet holding device according to claim 1 or 2, an image forming unit for forming an image on a sheet, and a sheet discharge guiding a sheet passing through the image forming unit to the temporary sheet holding device. A pair of rollers, a re-feed path for re-feeding a sheet from the pair of discharge rollers to the image forming unit,
Final discharge control means for discharging the sheet without re-feeding the sheet by rotating the sheet discharge roller pair and the transport roller pair in a state where the switching means is oriented in the first path, and the switch means To the second path, and reversely rotate the discharge roller pair before the trailing edge of the sheet passes, thereby re-feeding the sheet whose length in the traveling direction is equal to or more than the predetermined length. First re-feed control means;
By setting the switching means in the state of the first path and rotating the pair of discharge rollers in reverse before the trailing edge of the sheet passes, the sheet having a length less than the predetermined length in the running direction can be regenerated. An image forming apparatus comprising: a second sheet re-feed control unit for feeding a sheet. 6. The image forming apparatus according to claim 5, wherein the second sheet re-feed control unit stops or reversely rotates the pair of conveying rollers. 7. One of claims 3 to 6
In the image forming apparatus described in (1), the predetermined length is set to the second length by the switching unit in a state of facing a second path.
Wherein the leading end of the sheet has a length protruding from a gap between the machine body and the image forming apparatus main body before the trailing end of the sheet that has advanced to the path passes through the discharge roller pair. .