JPH0270677A - Picture forming device - Google Patents

Abstract

PURPOSE:To improve takeout action of a paper sheet in its accumulating condition stabilized in a stacker by enabling the stacker to be selectively set to a silt condition, placing a paper refeed side in the tilt upper end, and to a condition that the paper refeed side can be displaced turning to the bottom with a paper accepting side serving as the supporting point. CONSTITUTION:In accumulation of a paper sheet, when a stacker 91 is supported to a tilt condition with a paper refeed side in the tilt upper end, this stacker 91 obtains a stable condition of accumulating the paper sheet improving its taking out. While in the time of processing a jam and so on, the stacker 91 is displaced turning the paper refeed side to the bottom. Thus enabling large jam processing space to be ensured in the upper of the stacker 91, jam processing can be facilitated with no necessity for large exclusive space.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention is directed to stacking sheets of paper with an image formed on one side in a stacker, and then stacking the sheets of paper with an image formed on one side in order to form an image on the other side. The present invention relates to an image forming apparatus with a double-sided copying function that is guided to an image transfer section.

(Prior Art) In recent years, various functions have become more versatile, and various image forming apparatuses capable of double-sided copying have been put into practical use.

Conventionally, in this type of image forming apparatus, there is a
A structure incorporating an automatic double-sided image forming device (ADD) in which the sheets with edges formed on one side that have passed through the fixing device are once accumulated in a stacker and guided to an image transfer unit to form an image on the other side again. It becomes.

Further, the conventional automatic double-sided image forming apparatus has a structure in which a stacker is provided horizontally below a paper conveyance path that passes through an image transfer section and reaches a fixing device.

(Problems to be Solved by the Invention) With such a conventional configuration, since the stacker is in a horizontal state, there are problems in that the sheets cannot be stacked in an orderly manner, and unloading errors are likely to occur.

The present invention has been made based on the above-mentioned circumstances, and its purpose is to enable paper to be stacked in a stacker in an orderly manner and to be taken out easily, and also to easily handle jams without requiring a large dedicated space. It is an object of the present invention to provide an image forming apparatus that can obtain the following information.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method for stacking sheets on which an image is formed on one side in a stacker, and then forming an image on the other side. In the image forming apparatus, the stacker is arranged in an inclined state in which the paper re-feeding side is at the upper end of the inclination, and in a state in which the paper re-feeding side can be rotated downward with the paper receiving side as a fulcrum. The configuration is such that it can be set to

(Function) That is, in the present invention, by supporting the stacker in an inclined state where the paper re-feeding side is the inclined upper end when stacking papers, the stacking state of the papers in the stacker is stabilized and good removal is possible. Additionally, when clearing a jam, by rotating the stacker downward from the paper refeed side, a large space for clearing the jam can be secured above the stacker, making it easy to clear the jam without requiring a large dedicated space. It becomes possible.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the internal configuration of the entire image forming apparatus. In the figure, 1 is an apparatus main body that incorporates image forming process constituent means 2 such as charging, exposure, development, transfer, cleaning, and fixing. On the top surface, there is a document holding cover 4 that can be opened and closed and has a platen sheet 4a that holds down the document set on the platen glass 3 serving as a document placement table, and a document holding cover 4 that can be opened and closed to hold the document set on the document tray 5. An automatic document feeder (ADF) 7 is provided which includes a document feed mechanism section 6 that takes out sheets one by one and automatically feeds them between the platen glass 3 and the platen sheet 4a and discharges them onto the document holding cover 4. It is being Furthermore, an operation panel (not shown) on which a numeric keypad, a guide display section, a copy key, etc. are arranged is arranged on the front edge of the upper surface of the main body 1 of the apparatus.

On the right side of the apparatus main body 1, there are a paper feed cassette 10 containing paper P such as regular paper and paper feed to be supplied to the image forming process configuration means 2, a large capacity paper feeder (LCF) 11, and a manual paper feed stand. 12 is installed. In addition, the device main body 1
A sorter 13 for collecting fixed sheets P is installed on the left side of the apparatus, and a bin at the bottom of a tray unit 15 attached to the outside of the apparatus main body 1 of the sorter 13 is installed at the bottom of the apparatus main body 1. An automatic double-sided image forming device (ADD) 17 is provided, with 15f serving as a reversing tray 16.

The image forming process configuration means 2 has the following configuration. That is, a drum-shaped photoreceptor 20 serving as an image carrier is arranged approximately in the center of the apparatus main body 1, and a charging device 2 is arranged around the photoreceptor 20 along its rotation direction.
1. An exposure section 22a of the exposure device 22, an upper development unit 23a for color development, and a lower development unit 2 for black development.
3b, a developing device 23. Transfer device 24. A peeling device 25, a cleaning device 26, etc. are arranged in this order.

Further, inside the main body 1 of the apparatus, a sheet P1 is automatically fed from the paper feed cassette 10 or the large capacity paper feed device 11.
Alternatively, the paper P manually fed via the manual paper feed table 12 is passed through an image transfer section 27 serving as an image forming section between the photoreceptor 20 and the transfer device 24, and then transferred to an image transfer section 27 provided on the left side of the apparatus main body 1. A paper transport path 28 leading to the sorter 13 is formed.

A registration roller pair 29 is arranged on the upstream side of the image transfer section 27 of the paper conveyance path 28, and a fixing device 30 is arranged on the downstream side. Furthermore, an image transfer section 27 and a fixing device 30
A suction conveyance means 31 is disposed between the fixing device 30 and the tray unit 15 of the sorter 13, and a conveyance roller pair 32. and tray unit 15
A paper carrying means 33 is provided for sorting and carrying paper P into each of the bins 15a to 15f.

On the other hand, in the vicinity of the attached portion of the paper feed cassette 10, there is a
a take-out roller 40 that is attached to a conventional arm and takes out sheets P one by one; and a first branch conveyance path that receives the sheets P taken out through the take-out roller 40 and forms the upstream side of the paper conveyance path 28. Separation and conveyance means 41 consisting of a conveyance roller for feeding into 28a and a separation roller is provided. Also, in the vicinity of the large-capacity paper feeder 11, there is a take-out roller 42 that is attached to a swingable arm and takes out sheets P one by one, and a take-out roller 42 that receives the sheets P taken out through this take-out roller 42 and Separation conveyance means 43 is provided, which is composed of a conveyance roller and a layer separation roller that feeds into the second branch conveyance path 28b that forms the upstream side of the conveyance path 28. Further, in the vicinity of the manual paper feed table 12, a third branch conveyance path 2 is provided which merges the manually fed paper P with the second branch conveyance path 28b.
A pair of manual feed rollers 44 for feeding the paper into the paper 8c is provided.

Note that the charging device 21. Exposure device 22. Developing device 23
．． Transfer device 24. Peeling device 25. Cleaning device 26. Since the fixing device 34 and the like have well-known configurations, detailed explanations thereof will be omitted.

Note that a cooling fan 45 is disposed above the paper ejection roller pair 31 in the apparatus main body 1 .

Further, the image forming apparatus configured in this manner is separated into an upper unit IA and a lower unit IB with the paper transport path 28 as a border, and the upper unit IA and the lower unit IB are separated from each other as necessary.
It can be opened clockwise in the figure with A as the pivot point (not shown) as the center of rotation. The upper surface side of the paper transport path 28 from the pair of registration rollers 29 to the paper transport means 33 can be opened.

The document feeding mechanism section 6 of the automatic document feeder (ADF) 7 includes a pickup roller 46 that is movable up and down to approach and separate from the document D set on the document tray 5. Single sheet take-out means 47 consisting of a supply roller and a separation roller. and a pair of registration rollers 48, each of which is rotationally driven in a predetermined direction via a drive system (not shown). Further, the right scale 49 is rotatably mounted around the axis of the lower roller of the pair of registration rollers 48, and is driven by a solenoid (not shown).

Furthermore, a feeding roller 50 is provided on the left side of the right scale 49 and in rolling contact with the upper surface of the right end side of the platen glass 3, and is selectively rotated in both forward and reverse directions by the drive system (not shown) to feed the original. It is designed to send in and discharge. Further, a document discharge section 52 is formed above the right scale 49 to discharge the document discharged by the feeding roller 50 to a discharge document storage section 51 formed from the upper surface of the document holding cover 4 . The document discharge section 52 is arranged to form a document discharge path 54 between a first guide plate 53 whose lower end faces near the tip of the right scale 49 and the first guide plate 53. It is comprised of a gate 55 , a second guide plate 56 , and a pair of discharge rollers 57 disposed at the terminal end of the document discharge path 54 . The gate 55 is rotatably attached to a horizontally suspended shaft, and its lower end is inserted under its own weight into a groove formed in the upper surface of the free end side of the right scale 49.

Further, the right half of the platen sheet 4a is configured to be rotated by a predetermined angle by a gap forming means (not shown), and a wedge-shaped gap is created between the platen glass 3 and the platen sheet 4a when carrying in and out of the original document. It has a configuration that allows it to form.

Therefore, in the automatic document feeder 7 having such a configuration, there is no need for a wide conveyor belt or a belt drive mechanism for the document holding cover 4, so the cost of the automatic document feeder 7 can be significantly reduced. This makes it possible to reduce the weight of the cover part 4, and it becomes possible to open and close it easily in the same way as a normal document holding cover. Moreover, since there is nothing rotating and running in contact with almost the entire surface of the platen glass 3, large amounts of power and power are not required, and the amount of power and power required for the automatic document feeder 7 can be reduced and noise can be reduced. .

Further, since a wedge-shaped gap is formed between the platen glass 3 and the platen sheet 4a by the gap forming means,
Even a somewhat stiff document printer can be reliably fed and ejected.

Further, the paper feed cassette 10 accommodates three large sizes of paper P, and the large capacity paper feed device 16 accommodates frequently used A4 size paper P.

The large-capacity paper feeding device 16 includes a take-out roller 42 as a paper feeding means, and is provided below the take-out roller 42 so as to be able to rise and fall, and is capable of handling 1000 sheets (2 or more packages each containing 500 sheets). The uppermost sheet of paper P is fed by the take-out roller 42 by running an endless belt whose vertical portion is connected to the sheet loading table (elevator tray) 60 and the sheet loading table 60. The system is equipped with a belt-driven paper table moving means (not shown) that moves the paper table to a position suitable for the paper table. It is designed to be supplied separately. Note that 61 is a safety cover 61 that can be opened and closed and covers a portion of the large-capacity paper feeding device 11 that protrudes from the side surface of the main body 1 of the device.

The sorter 13 also includes a tray unit 15 that is removably attached to the outside of the apparatus main body 1 and that sorts and stacks sheets, and a tray unit 15 that is provided inside the apparatus main body 1 and that feeds the paper P that has passed through the fixing device 30 to the tray unit 15. It is composed of a carrying means 33. As shown in FIGS. 3 to 5, the tray unit 15 holds a plurality of bins 15a to 15f (six in this embodiment) at a predetermined interval in the vertical direction, with their tips raised. It has a configuration arranged in
Further, the paper carrying means 33 includes a movable guide means 65 and a pair of vertically movable transfer rollers 66 provided at the exit portion of the movable guide means 65.

The movable guide means 65 is connected to the conveying roller pair 3 in the apparatus main body 1.
A first guide plate 68 is rotatably connected to the guide plates 67 and 67 disposed near the first guide plate 67 and the first guide plate 68 via a support shaft.
．． 68, and a guide plate 70.7 integrated with the movable unit 69 into which these first guides 1hL68.68 are slidably inserted and on which the transfer roller pair 66 is mounted.
0 and second guide plates 71 and 71 rotatably connected to each other via a support shaft.

Further, as shown in FIG. 3, the transfer roller pair 66 includes lower rollers 66a... and an upper roller 66b that rolls into contact with these rollers.
The lower rollers 66a are configured to be rotationally driven by a driving means 75 mounted on the movable unit 69. The driving means 75 is the motor 7
6 is configured to transmit the driving force of 6 to a shaft 78 to which lower rollers 66a are attached via a power transmission system 77 consisting of a pulley, a belt, and a pulley.

Further, both ends of the movable unit 69 on which the transfer roller pair 66 is mounted are connected to endless belts 82 and 82 stretched through pulleys 80 and 81, respectively, and these endless belts 82. Pulley 8 with 82 wrapped around it
1.81 is moved up and down by rotating it in a predetermined direction via a drive means 83. Drive means 83
is configured to transmit the driving force of a pulse motor 84 to a shaft 86 to which pulleys 81 and 81 are attached via a power transmission system 85 that also serves as a speed reduction mechanism and includes a pulley, a belt, and a bobbin.

Therefore, the movable unit 6 equipped with the transfer roller pair 66
9 moves up and down, along with this movement, the transfer roller pair 6
6 is a predetermined bin 15 as shown in FIGS. 5(a) to 5(c).
It faces a to 15f. At this time, the movable guide means 65
1. Second guide plate 68, 68, 71.7
1 swings about the support shaft and expands and contracts to form the fixing device 30.
The sheet P sent out from the pair of conveying rollers 32 arranged immediately after the pair of conveying rollers 66 is guided to the pair of conveying rollers 66 . FIG. 5(a) shows the state in which the paper P is sent to the topmost bin 15a, and FIG. 5(b) shows the state in which the paper P is sent to the third bin 15c.
Figure 5(c) shows the state in which the bottom bin 15f is sent out.
2 shows the state in which the paper P is sent out.

Next, the automatic double-sided image forming device (ADD) 17 will be explained with reference to FIGS. 6 to 13.

The automatic double-sided image forming device 17 includes a reversing tray 16 consisting of the lowermost bin 15f of the tray unit 15 of the sorter 13, and the sorter 13 into which the paper P that has passed through the fixing device 30 is fed into the reversing tray 16. a paper loading means 33; a taking-out means 90 for taking out the paper P fed into the reversing tray 16 by the paper loading means 33 from the rear end side; and a stacker provided in an inclined manner at the bottom of the apparatus main body 1. 91, and the paper P taken out from the reversing tray 16 by the taking out means 90 is placed in the stacker 91.
a paper carrying out means 92 for carrying out the paper P that has been partially accumulated in the stacker 91 and taking out the paper P that has been partially accumulated in the stacker 91 and transporting the paper P again to the image transfer section 27;
The configuration includes a sheet take-out and conveyance means 93 that feeds the paper into the first branch conveyance path 28a for conveyance.

Further, as described above, the paper carrying means 33 is composed of a movable guide means 65 and a pair of vertically movable transport rollers 66 provided at the exit portion of the movable guide means 65, and this transport roller pair 66 is mounted. A paper discharge switch 95 is mounted on the movable unit 69.

Further, as shown in FIGS. 6 to 8, the take-out means 90 includes take-out rollers 100, 100, and a pinch pin partially exposed on the reversing tray 16 for rolling contact with these take-out rollers 100, 100. It is composed of rollers 101 and 101. The take-out rollers 100, 100 are provided at both ends of the drive shaft 102, and are vertically movable so as to approach and separate from the pinch rollers 101, 101 via a moving mechanism (not shown). Further, as shown in FIG. 7, the drive shaft 102 is connected to a sprocket and an endless chain, and the driving force of a motor 103 that can rotate in both forward and reverse directions is connected to the drive shaft 102.

The power is transmitted via a power transmission system 104 consisting of a sprocket and a sprocket.

Further, on the entrance side of the reversing tray 16, a gate means 105 is arranged as shown in FIGS. 6 to 8.

This gate means 105 includes gate 1 as shown in FIG.
The shaft 10'7 to which 06... is attached is rotatably displaced by a gate operating means 109 using a solenoid 108 as a driving source.

Further, as shown in FIGS. 6 and 7, the paper conveyance means 92 includes a first pair of feed rollers 1 located at the lower end of a moving path of a movable unit 69 on which the pair of transfer rollers 66 are mounted.
15, a second pair of feed rollers 116 provided at the entrance of the stacker 91, and a pair of these first feed rollers 116. Second feed roller pair 1
15 and 116, and a pair of guide plates 117 disposed between them. The first feed roller pair 115 includes lower rollers 66a of the moving roller pair 66 constituting a part of the paper carrying means 33, and these lower roller pairs 66a.
Pinch roller 118 arranged to make contact with...
・It is composed of.

Further, as shown in FIGS. 9 and 10, a shaft 7 to which the lower rollers 66a of the transfer roller pair 66 are attached is also provided.
8 is a driving gear 1 that forms part of the driving force transmission system 119.
20 is attached, and when the movable unit 69 carrying the transfer roller pair 66 reaches the paper loading/unloading position with respect to the reversing tray 16, the rotational force of the drive gear 120 is applied to the second feed roller pair 116. Lower roller 116a
It is now transmitted to... That is, the second
A gear 122 is fitted onto a drive shaft 121 to which the lower rollers 116a of the feed roller pair 116 are attached, and this gear 122 is a driven gear that can be freely engaged with and disengaged from the drive gear 120 via an intermediate gear 123. It is adapted to interlock with gear 124.

Then, as shown in FIG. 10(a), a pair of transfer rollers 66
The movable unit 69 equipped with
5a to the paper loading position for the fifth bin 15e, the drive gear 120 that rotates together with the lower rollers 116a is separated from the driven gear 124, and the second feed roller pair 116 lower roller 116a of
Rotational force is not transmitted to... At this time, the lower roller 66a of the transfer roller pair 66 is separated from the pinch roller 118, and the first feed roller pair 115 is also inactive.

Further, as shown in FIG. 10(b), a movable unit 69 equipped with a pair of transfer rollers 66 is moved to the lowermost sixth bin 15.
When the paper reaches the paper loading/unloading position with respect to the reversing tray 16 consisting of a, the lower rollers 116a and
The driving gear 120 that rotates together with... is the driven gear 124
The rotational force of the drive gear 120 is in mesh with the second
The lower rollers 116a of the pair of feed rollers 116 are transmitted. At this time, the transfer roller pair 6
The lower roller 66a of No. 6 is in rolling contact with the pinch roller 118, and the first feed roller pair 115 is also in an operating state.

FIG. 11 shows the operation of loading and unloading paper P into and out of the reversing tray 16.

First, the paper P that has passed through the fixing device 30 is transferred to the reversing tray 1.
6, the movable unit 69 carrying the pair of transfer rollers 66 of the paper carrying means 33 is lowered to the lower limit position and the lower roller 66a is driven, as shown in FIG. 11(a). It is in. On the other hand, the tip of the gate 106 disposed in the reversing tray 16 is raised to face the upper roller 66b, and the take-out roller 100 is displaced upward. Then, the sheet P guided by the movable guide means 65 is transported by a pair of transport rollers 66 and fed into the reversing tray 16 such that its leading end passes through the gate 106 and the lower surface side of the take-out roller 100.

Then, as shown in FIG. 11(b), when the rear end of the paper P is fed into the reversing tray 16, the take-out roller 100
descends while reversing, and the rear end of the paper P is transferred to the transfer roller pair 6.
Send it a little to remove 6. Note that the lowering operation of the take-out roller 100 is controlled by the detection operation of the paper ejection switch 95.

Then, as shown in FIG. 11(C), when the trailing edge of the paper P comes off the transport roller pair 66, the reversal of the take-out roller 100 is stopped and the gate 106 flicks the trailing edge of the paper P downward. . At this time, the leading edge of the subsequent paper P is guided by the movable guide means 65, so that the image forming ability of the image forming process configuration means 2 is not reduced.

Next, as shown in FIG. 11(d), the take-out roller 10
0 rotates in the forward direction (take-out direction), and the rear end side of the paper P is moved between the lower roller 66 of the transport roller pair 66 and the pinch roller 11.
8, and when the rear end of the paper P is sent between the lower roller 66a of the transfer roller pair 66 and the pinch roller 118, the gate 106 is immediately raised as shown in FIG. 11(e). Immediately after that, the leading edge of the following paper P is sent by the transport roller pair 66. Further, at the time when the leading edge of the subsequent sheet P is carried under the gate 106, the take-out roller 100 is in a lifted state.

At this time, as shown in FIG. 11(f), the ejecting operation of the preceding paper P and the carrying-in operation of the subsequent paper P are performed in parallel in the reversing tray 16, and the paper P , P are overlapped with each other in opposite moving directions, so that the image forming pitch by the image forming process configuration means 2 can be maintained.

Then, when the trailing edge of the succeeding sheet P is fed into the reversing tray 16, as shown in FIG. It will be in a state where it will be sent a little as it comes off. Note that, at this time, most of the preceding paper P has been fed into the stacker 91, and its rear end is caught on the rear end sides of the second pair of feed rollers 116 and the pair of guide plates 117.

Then, as shown in FIG. 11(h), when the trailing edge of the paper P comes off the transport roller pair 66, the reverse rotation of the take-out roller 100 is stopped and the gate 106 flicks the trailing edge of the paper P downward. . At this time, the leading edge of the succeeding sheet P is guided by the movable guide means 65, and the trailing end of the preceding sheet P is guided by the second feed roller pair 1.
It is on the verge of falling out of 16.

Then, as shown in FIG. 11(i), the take-out roller 10
0 rotates in the forward direction (takeout direction), and the lower roller 66 of the transport roller pair 66 moves the rear end side of the paper P in the reversing tray 16.
and the pinch roller 118, and again the first
The operations from FIG. 1(e) onwards are repeated. At this time, the preceding sheets P are stacked in the stacker 91.

Further, on the inclined upper end side of the stacker 91, as shown in FIGS. 2 and 8, there is provided a take-out roller 130 that can move up and down to take out the uppermost sheets P accumulated in the stacker 91 one by one. A pair of conveyance rollers 131 is provided to send the paper P taken out by the ejecting port roller 130 to the first branch conveyance path 28a in order to convey it again to the image transfer section 27. It consists of

Further, the stacker 91 is provided with a movable stopper 132 that automatically moves to a predetermined position according to the size of the stacked sheets P and causes the sheets to face the take-out roller 130.

Further, the stacker 91 is located on the paper input side, that is, on the second side.
It is rotatable about the lower roller 116a of the feed roller pair 116 as a rotation fulcrum, and a stacker rotation means 99 is provided below the free end side thereof.

This stacker rotation means 99 includes a pair of torque links 96 and 96 disposed at a position that abuts the bottom surface of the stacker 91.
(only one is shown), a shaft 97 to which these torque links 96 and 96 are attached, and an operating lever 98 attached to one end of this shaft, and by rotating the operating lever 98, the torque link 96 The .96 can be stood up almost vertically or laid down almost horizontally.

When stacking sheets P, the torque links 96° 96 are erected almost vertically, and the stacker 91 is tilted as shown by the solid line in FIG. The sheets are stacked in an orderly manner based on the standard, so that paper can be re-feeded properly.

Furthermore, when clearing a jam, a large space is secured above the stacker 91 by tilting the torque link 96° 96 to a nearly horizontal position and placing the stacker 91 in a horizontal position as shown by the solid line in FIGS. 13 and 1. To facilitate jam processing.

The direction of arrow a shown in FIG. 1 indicates the direction in which the jam in the stacker 91 is cleared, and the direction indicated by the arrow indicates the direction in which paper jam in the reversing tray 16 is cleared.

Next, a double-sided copying operation for A3 size paper P stored in the paper feed cassette 10 will be explained with reference to FIGS. 2 and 14. First, as shown in FIG. 2, after setting the document tray directly on the platen glass 3 or on the document tray 5 of the automatic document feeder 7, select the paper size, number of copies, 1 double-sided copy from the operation panel (not shown). ,
After inputting various image forming conditions such as color designation, a copy key (not shown) is pressed. As a result, the drum-shaped photoreceptor 20 (see figure m2) rotates in the direction of the arrow (clockwise), and the photoreceptor 20 is uniformly charged by the charging device 21. On the other hand, an original set on the platen glass 3 is scanned by the exposure device 22, and a slit is exposed onto the photoreceptor 20. Then, an electrostatic latent image corresponding to the original is formed on the photoreceptor 20.

The electrostatic latent image on the photoreceptor 20 is developed and visualized by the upper developing unit 23a or the lower developing unit 23b of the developing device 23 based on the color designation from the operation panel.

On the other hand, in synchronization with this developer image forming operation, as shown in FIG.
As shown in a), the paper P is automatically loaded from the paper cassette 10.
is taken out, this paper P is sent to the image transfer section 27 via the registration roller pair 29, and the developer image previously formed on the photoreceptor 20 is transferred to the paper P by the action of the transfer device 24. Then, the paper P is peeled off from the photoreceptor 20 by the peeling device 25 and conveyed to the fixing device 30 side.

After the developer image is transferred onto the paper P, the photoreceptor 20 faces the cleaning device 26 to clean the remaining developer (residual toner) and return to a normal state in which the next copying operation can be performed. .

On the other hand, the developer image is melted and fixed onto the paper P by being sent to the fixing device 30, and the device 30
The paper P that has passed through is guided to the reversing tray 16 as shown in FIG. 14(b). Immediately after the rear end of the paper P enters the reversing tray 16 as shown in FIG. 14(c), it is taken out from the reversing tray 16 and placed on the stacker 91 side as shown in FIG. 14(d). It is guided and stored in the stacker 91 as shown in FIG. 14(e). At this time, since the stacker 91 is in an inclined state, the sheets P are stacked in an orderly manner with their inclined lower ends aligned.

At this time, although omitted in FIG. 14, since the image forming operation by the image forming process configuration means 2 is performed continuously, the image is formed as described above with reference to FIG. It goes without saying that the paper P is continuously fed to the reversing tray 16 side.

In this way, when a predetermined amount of sheets P are stacked on the stacker 91 as shown in FIG. 141(f), a display to that effect is displayed on the operation panel section. As a result, by replacing the document tray and pressing the copy key again, the document tray is scanned, and an image is formed on the photoreceptor 20 as described above.
As shown in Figure (g), the take-out roller 130 descends, and the paper P in the stacker 91 is taken out and sent to the image transfer section 27 with the non-image-formed side facing up. Then, after being fixed as shown in FIG. 11(h), it is fed into the topmost bin 15a of the tray unit 15, for example. This continues until the last sheet P is taken out from the stacker 91, as shown in FIG. 14(i).

Further, FIG. 15 shows A
This explains the double-sided copying operation for four sizes of paper P, and the stacker 91 shown in FIGS. 15(a) to (h)
The process up to the stacking process is the same as in the case of the A3 size paper P shown in FIG. 14 described above.

Then, as shown in FIG. 15(h), a predetermined amount of paper P is accumulated on the stacker 91, and as shown in FIG. 15(i), the movable stopper 132 moves to collect the paper P... and move it to a position where it can be taken out by the take-out roller 130.

After this, in the same manner as described above, by replacing the document sheet and pressing the copy key, the image forming operation on the other side of the paper P is performed, that is, the same steps as in FIGS. 14(g) to (i) are performed. The operations shown in FIG. 15 (j) to (0) will be performed.

Note that image formation is performed in the same manner on the paper P fed from the manual paper feed tray 12. In addition, in the case of single-sided copying, the sheets are directly discharged into a predetermined bin of the toy unit 15 for re-sorting without being led to the automatic double-sided image forming device 17.

Further, FIG. 16 is an illustration diagram showing the loading/unloading operation of paper P to and from the reversing tray 16, in which FIG. 16(a) is in a state corresponding to the above-mentioned FIG. 11(a), and FIG. 16(b)
is the state corresponding to the above-mentioned FIG. 11(b), and FIG. 16(c)
) is the state corresponding to the above-mentioned FIG. 11(c), and FIG. 16(
d) shows a state corresponding to the above-mentioned FIG. 11(d), and FIG. 16(e) shows a state corresponding to the above-mentioned FIG. 11(e).

Further, FIG. 17 is an illustration diagram showing the conveyance state of paper P taken out from the large-capacity paper feeder 11 during double-sided copying, and FIG. 17(a) corresponds to the above-mentioned FIG. 15(d). FIG. 17(b) is a state corresponding to the above-mentioned FIG. 15(f), FIG. 17(c) is a state corresponding to the above-mentioned FIG. 15(h), and FIG. 17(d) is a state corresponding to the above-mentioned FIG. FIG. 17(e) shows a state corresponding to FIG. 15(i) described above, and FIG. 17(e) shows a state corresponding to FIG. 15(j) described above.

It goes without saying that the present invention is not limited to the above-mentioned embodiment, and can be modified in various ways without departing from the gist.

[Effect of the Invention J As explained above, the present invention has a structure in which, after sheets with an image formed on one side are once accumulated in a stacker, the sheets are guided to the image transfer section in order to form an image on the other side. In the image forming apparatus, the stacker is configured to be set in an inclined state where the paper re-feeding side is the inclined upper end and in a state in which the paper re-feeding side can be rotated downward with the paper receiving side as a fulcrum. By supporting the sheets in an inclined state with the re-feeding side being at the upper end of the slope during stacking, the stacked state of the sheets in the stacker is stabilized and good removal is possible.

Additionally, when clearing a jam, by rotating the stacker downward from the paper refeed side, a large space for clearing the jam can be secured above the stacker, making it easy to clear the jam without requiring a large dedicated space. It has the effect of making it possible.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic perspective view showing the configuration of the main parts, FIG. 2 is a schematic longitudinal sectional front view of the entire image forming apparatus, and FIG. A schematic perspective view showing the configuration of a paper transport means for transporting paper into a bin;
FIG. 4 is a schematic front view, FIG. 5 is an explanatory diagram showing the state in which sheets are carried into each bin, FIG. 6 is a schematic front view showing the configuration of the main parts of the automatic double-sided image forming apparatus, and FIG. 7 is a schematic perspective view, FIG. 8 is a schematic perspective view showing the configuration of the automatic double-sided image forming apparatus, FIG. 9 is a schematic perspective view showing the drive system, and FIG. 10 is the same drive system. FIG. 11 is an explanatory diagram showing the state of driving force connection and disconnection of the parts, FIG. 11 is an explanatory diagram showing the state of paper being carried into and out of the reversing tray during automatic double-sided copying, and FIG. 12 is a schematic diagram showing the configuration of the stacker rotating means. A perspective view, FIG. 13 is a schematic front view showing the configuration of the stacker rotating means, and FIG. 14 is an explanatory diagram showing the flow of paper during automatic double-sided copying for large-sized paper fed from the paper feed cassette. , FIG. 15 is an explanatory diagram showing the flow of paper during automatic duplex copying for small-sized paper fed from a large-capacity paper feeder, and FIG. 16 is an illustration showing the flow of paper into the reversing tray during automatic duplex copying and FIG. 17 is an illustration showing the unloading state. FIG. 17 is an illustration showing the flow of paper during automatic double-sided copying for small size paper. 17... Automatic double-sided image forming device, 29... Image transfer section, 91... Stacker, P... Paper. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 1N4 Figure (a) (b) Figure Figure Figure Figure

Claims (1)

[Claims] In an image forming apparatus in which sheets of paper with an image formed on one side are once accumulated in a stacker and then guided to an image transfer section in order to form an image on the other side, the stacker is arranged such that the paper re-feeding side has an inclined upper end. An image forming apparatus characterized in that the image forming apparatus is configured to be able to be set in an inclined state and a state in which the paper refeeding side can be rotated downward using the paper receiving side as a fulcrum.