JPH0266079A - Image forming device - Google Patents

Abstract

PURPOSE:To facilitate jam handling by providing an inverting tray outside a device body, providing a stacker onto which sheets of paper taken out of the inverting tray by a take-out means are fed by a conveying means inside the device body, and providing a paper take-out/conveying means for taking out the sheets of paper temporarily stacked on this stacker and again conveying same to an image forming portion. CONSTITUTION:Sheets of paper passed through an image forming portion and fixing device are sent into an inverting tray 16 outside a device body by a carry-in means. The sheets of paper sent into the inverting tray 16 are taken out by a take-out means 90 and carried out onto a stacker 91 inside the device body by a carry-out means 92. The sheets of paper temporarily stacked on this stacker 91 are taken out by a paper take-out/conveying means 93 and again conveyed to the image forming portion. As a result, there is no need of providing a long paper carry-in passage between a paper conveying passage leading to the fixing device via the image forming portion and the stacker 91 and a large space can be ensured above the stacker 91 while enabling the inverting tray 16 to be placed outside the device body, to facilitate jam handling while miniaturizing the whole device.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Application Field) The present invention is directed to an apparatus having an image forming process component built in the apparatus main body, and a paper fed to an image forming section of the image forming process component. It relates to an image forming apparatus that forms an image corresponding to a document on a document, and then fixes this image on a sheet of paper using a fixing device, and in particular, the sheet of paper that has passed through the fixing device is guided back to an image transfer section to perform double-sided copying. Automatic double-sided image forming device (
The present invention relates to an image forming apparatus equipped with ADD).

(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
It has a built-in automatic double-sided image forming device that can guide the paper that has passed through the fixing device to the image transfer section again.

In addition, in the conventional automatic double-sided image forming apparatus, a sheet of almost horizontal S-shape is constructed with a plurality of pairs of guide plates and pairs of transport rollers between a sheet conveyance path that passes through an image transfer section and reaches a fixing device, and a stacker. A carry-in path is provided, and the paper that has passed through the fixing device is sent into the paper carry-in path via a gate means, and once transported in the opposite direction and stacked in a stacker with the image forming surface facing upward;
Next, the sheets stacked in this stacker are taken out one by one by the take-out means, and image-transferred through an arcuate conveyance path with the non-image-formed surface facing upward, that is, the non-image-formed surface facing the image carrier. It is structured so that it can be sent to the department.

(Problems to be Solved by the Invention) In such a conventional configuration, a plurality of pairs of guide plates and paper transport paths are provided between the stacker and the paper conveyance path that passes through the image forming section (image transfer section) and reaches the fixing device. There is a long paper feed path consisting of a pair of rollers, which not only makes it difficult to clear jams, but also
It is necessary to take up a large amount of exclusive space for the automatic double-sided image forming device on the lower side of the paper conveyance path, which inevitably increases the height of the image forming device, which poses an obstacle to miniaturization. was there.

The present invention has been made based on the above-mentioned circumstances, and its object is to provide an image forming apparatus equipped with an automatic double-sided image forming device capable of guiding paper that has passed through a fixing device back to an image forming section to perform double-sided copying. It is easy to handle jams in
Moreover, it is an object of the present invention to provide an image forming apparatus that does not require a large dedicated space as an automatic double-sided image forming apparatus and can be downsized.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention incorporates an image forming process configuring means in the main body of the apparatus, and provides an image-forming process that is sent to the image forming section of the image forming process configuring means. In an image forming apparatus that forms an image corresponding to a document on a sheet of paper, and then fixes this image on the paper using a fixing device, the image forming apparatus includes a reversing tray provided in the main body of the apparatus, and a reversing tray that is attached to the reversing tray. a paper carry-in means for feeding the paper that has passed through the paper, a take-out means for taking out the paper sent into the reversing tray from the rear end side by the paper carry-in means, a stacker provided in the apparatus main body, and a stacker provided in the apparatus main body; Automatic double-sided image formation comprising: a paper transport means for transporting the paper taken out from the tray to the stacker; and a paper take-out transport means for taking out the paper temporarily accumulated in the stacker and transporting it again to the image transfer section. It is equipped with a device for

Further, the paper carrying-in means may include a movable guide means and a pair of vertically movable transfer rollers provided at an exit portion of the movable guide means, and the pair of transfer rollers also serves as a feed roller of the paper carrying-out means. This is what I did.

Further, when the vertically movable pair of transport rollers that also serve as the feed rollers of the paper transport means reach the paper loading/unloading position relative to the reversing tray, the driving force of the transport rollers is transmitted through the driving force transmission system. and is configured to be transmitted to another feed roller of the paper conveyance means.

(Function) That is, the present invention includes an automatic double-sided image forming apparatus including a reversing tray provided in the main body of the apparatus, a paper carrying means for feeding the paper that has passed through an image forming section and a fixing device into the reversing tray in sequence, a take-out means for taking out the paper fed into the reversing tray by the paper carry-in means from the rear end side;
a stacker provided in the apparatus main body; a paper ejection means for ejecting the paper taken out from the reversing tray by the ejection means to the stacker; and a paper ejection means for ejecting the paper temporarily accumulated in the stacker and returning it to the image forming section. Since it is configured with a paper take-out and conveyance means for conveying the paper, a long paper conveyance path consisting of a plurality of pairs of guide plates and pairs of transfer rollers is constructed between the stacker and the paper conveyance path that passes through the image forming section and reaches the fixing device as in the past. There is no need to provide a paper path, and moreover, a large space can be secured above the stacker, and the reversing tray is located outside the main body of the device, making it easy to clear jams. The dedicated space can be reduced and the image forming apparatus can be downsized.

Further, the paper carrying-in means may include a movable guide means and a pair of vertically movable transfer rollers provided at an exit portion of the movable guide means, and the pair of transfer rollers also serves as a feed roller of the paper carrying-out means. Therefore, it is possible to reduce the number of parts in the paper conveyance section, simplify the configuration, reduce costs, and facilitate jam handling.

Further, when the pair of vertically movable transport rollers that also serve as the feed rollers of the paper transport means reach the paper loading/unloading position with respect to the reversing tray, the driving force of the transport roller pair is transmitted through the driving force transmission system. Since the transmission is transmitted to the other feed roller of the paper transport means, a dedicated drive source is not required, and since the feed roller does not rotate except when forming double-sided images, it is possible to reduce noise during normal use. .

(Embodiment) Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 14.

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 plain paper to be supplied to the image forming process configuration means 2, a large capacity paper feeder (LCF) 11, and a manual paper feed tray 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 23a 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 conveyance path 28 is formed in the ivy 13.

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 installed portion of the paper feed cassette 10, there is a take-out roller 40 that is attached to a swingable arm and takes out the sheets P one by one, and a take-out roller 40 that receives the sheets P taken out through the take-out roller 40. Separation conveyance means 41 is provided, which is composed of a conveyance roller that feeds the paper into the first branch conveyance path 28a forming the upstream side of the paper conveyance path 28, and a separation roller. 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 consisting of a conveyance roller and a separation roller for feeding into the second branch conveyance path 28b forming the upstream side of the conveyance path 28 is provided. Furthermore, the paper P that is manually fed Lt near the manual paper feed table 12
A pair of manual feed rollers 44 for feeding the paper into the third branch conveyance path 28c that merges with the second branch conveyance path 28b 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 extending from the two registration roller pairs to the paper carrying 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 ejecting section 52 has a first guide plate 53 whose lower end faces near the tip of the right scale 49 and a document ejecting path 54 formed between the first guide plate 53 and the first guide plate 53 . The gate 55 is composed of a gate 55, a second guide plate 56, and a pair of discharge rollers 57 disposed at the end of the document discharge path 54.The gate 55 is rotatable about a horizontally extending shaft. The lower end of the right scale 49 is inserted into a groove formed in the upper surface of the free end side of the right scale 49 under its own weight.

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), so that 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 large A3 size 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 68.
68, these first guide plates 68, 68 are slidably inserted, and are rotatable via support shafts on guide plates 70, 70 which are integrated with six movable units on which the transfer roller pair 66 is mounted. The second guide plate 71', 71 is connected to the second guide plate 71'.

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 and 81 are rotated in a predetermined direction via a drive means 83 to move up and down. Drive means 83
is configured to transmit the driving force of the pulse motor 84 to a support 86 to which the pulleys 81, 81 are attached via a power transmission system 85 which also serves as a speed reduction mechanism and includes a pulley, a belt, and a pulley.

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 (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. 1 and 6 to 10.

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.
and a paper take-out and conveyance means 93 that takes out the sheets P temporarily accumulated in the stacker 91 and sends them to the first branch conveyance path 28a to convey them to the image transfer section 27 again. It has a configuration consisting of:

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 FIG. 1, FIG. 6, and FIG.
6 and pinch rollers 101, 101 partially exposed on top of the pinch roller 6.

The take-out rollers 100, 100 are provided at both ends of the drive shaft 102, and are connected to the pinch roller 101 via a moving mechanism (not shown).
, 101, and can freely move up and down so as to approach and separate from them. 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. 1, 6, and 7. As shown in FIG. 7, this gate means 105 has a structure in which a shaft 107 on which gates 106 are attached is rotationally 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 that constitute a part of the paper carrying means 33, and these lower roller pairs 66a.
Pinch roller 118 arranged to make contact with...
It is made up of.

Further, as shown in FIGS. 8 and 9, a shaft 78 to which the lower rollers 66a of the transfer roller pair 66 are attached
The drive gear 12 that forms part of the drive power transmission system 119 is
0 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 this drive gear 120 is applied to the second feed roller pair 116. Lower roller 1'16a
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 can be freely engaged with and disengaged from the drive gear 120 via an intermediate gear 123. It is designed to interlock with the driven gear 124.

Then, as shown in FIG. 9(a), a movable unit 69 equipped with a pair of transfer rollers 66 is moved to the first bin 15 on the uppermost stage.
At the position where the paper has arrived at the paper loading position from a to the fifth bin 15e, the drive gear 120, which rotates together with the lower rollers 116a, is separated from the driven gear 124, and the second feed Lower roller 116a of roller pair 116.
Rotational force is not transmitted to... At this time, the lower roller 66a of the transfer roller pair 66 is in a state separated from the pinch roller 118, and the first feed roller pair 115 is also in a non-operating state.

Further, as shown in FIG. 9(b), a movable unit 69 equipped with a pair of transfer rollers 66 is moved to the lowermost sixth bin 15a.
When the paper reaches the paper loading/unloading position for the reversing tray 16 consisting of the lower rollers 116a...
The drive gear 120 that rotates integrally with the driven gear 124 is in mesh with the driven gear 124, and the rotational force of the drive gear 120 is transmitted to the lower rollers 116a of the second feed roller pair 116. At this time, the lower roller 66a of the transfer roller pair 66 is in rolling contact with the pinch roller 118, and the first feed roller pair 115 is also in an operating state.

FIG. 10 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, as shown in FIG. 10(a), the movable unit 69 on which the transfer roller pair 66 of the paper carrying means 33 is mounted is lowered to the lower limit position, and the lower roller 66a is driven. 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. 10(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. 10(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. 10(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 118.
As soon as the rear end of the paper P is fed between the lower roller 66a of the transfer roller pair 66 and the pinch roller 118, the gate 106 is raised as shown in FIG. 10(e). Immediately thereafter, 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. 10(f), the ejecting operation of the preceding paper P and the carrying-in operation of the subsequent paper P are performed in parallel within 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, when the trailing edge of the paper P comes off the pair of transport rollers 66, as shown in FIG. . 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.

Next, as shown in FIG. 10(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. 0(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. 1 and 2, there is a take-out roller 130 that can freely move up and down to take out the uppermost sheets P accumulated in the stacker 91 one by one. A pair of conveying rollers 131 are disposed to send the paper P taken out by the take-out roller 130 to the first branch conveyance path 28a in order to convey it again to the image transfer section 27, and constitute the paper take-out conveying means 93. ing.

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

Next, a double-sided copying operation for paper P of three sizes housed in the paper feed cassette 10 will be explained with reference to FIGS. 2 and 11. 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 FIG. 2) 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 the photoreceptor 20 is exposed to slit light. 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 this fixing device 30
The paper P that has passed through is guided to the reversing tray 16 as shown in FIG. 11(b). Immediately after the trailing edge of the paper P enters the reversing tray 16, as shown in FIG. 11(c),
As shown in FIG. 11(d), the paper is taken out from the reversing tray 16, guided to the stacker 91 side, and stored in the stacker 91 as shown in FIG. 11(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 not shown in FIG. 11, 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, as shown in FIG. 11(f), when a predetermined amount of paper P is accumulated on the stacker 91, an image thereof 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. 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. Next, Figure 11 (
After being fixed as shown in h), it is fed into the uppermost bin 15a of the tray unit 15, for example. and,
This continues until the last sheet P is taken out from the stacker 91, as shown in FIG. 11(i).

Further, FIG. 12 shows A
This explains the double-sided copying operation for four sizes of paper P, and the stacker 91 shown in FIGS. 12(a) to 12(h)
The process up to the stacking process is the same as in the case of the A3 size paper P shown in FIG. 11 described above.

Then, as shown in FIG. 12(h), a predetermined amount of paper P is accumulated on the stacker 91, and as shown in FIG. 12(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 way 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. 11(g) to (i) are performed. The operations shown in FIG. 12 (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 one-time one-sided copying, it is only necessary to directly discharge the toy unit 15 into a predetermined bin or sort it without guiding it to the automatic double-sided image forming device 17.

Further, FIG. 13 is an illustration diagram showing the loading/unloading operation of paper P to and from the reversing tray 16, in which FIG. 13(a) is in a state corresponding to the above-mentioned FIG. 10(a), and FIG. 13(b) is in a state corresponding to the above-mentioned FIG. 10(a).
is the state corresponding to the above-mentioned FIG. 10(b), and FIG. 13(c)
) is the state corresponding to the above-mentioned FIG. 10(c), and FIG. 13(
d) shows a state corresponding to the above-mentioned FIG. 10(d), and FIG. 13(e) shows a state corresponding to the above-mentioned FIG. 10(e).

Further, FIG. 14 is an illustration diagram showing the conveyance state of the paper P taken out from the large-capacity paper feeder 11 during double-sided copying, and FIG. 14(a) corresponds to the above-mentioned FIG. 12(d). FIG. 14(b) is a state corresponding to the above-mentioned FIG. 12([), FIG. 14(c) is a state corresponding to the above-mentioned FIG. 12(h), and FIG. 14(d) is a state corresponding to the above-mentioned FIG. 12(h). FIG. 14(e) shows a state corresponding to the above-mentioned FIG. 12(1), and FIG. 14(e) shows a state corresponding to the above-mentioned FIG. 12(j).

15 to 17 show other embodiments of the main parts of the present invention, in which the gate 106 and the take-out roller 1 described above are shown.
00 and replace it with a rubber piece 140 on the lower roller 66.
It is rotatably attached to a shaft 78 to which a is attached. As shown in FIG. 16, the rubber piece 140 consists of a boss part 140a fitted onto the shaft 78, and a tongue part 140b projecting from the boss part 140a. The driving force is transmitted through a power transmission system 142 consisting of a pulley, a belt, and a boolean, and the motor rotates once at a predetermined timing. Further, during standby, the tongue portion 140b is stopped in a substantially horizontal state, as shown in FIGS. 15 and 16.

Figure 17 explains the effect, and Figure 17 (
As shown in a), when the paper P is fed into the reversing tray 16, it is in a standby state.

Then, as shown in FIG. 17(b), when the trailing edge of the paper P passes the paper ejection switch 95 and the switch is turned from ON to OFF, the rubber piece 140 starts rotating as shown in FIG. 17(C). . Then, as shown in FIG. 17(d), the rear end of the paper P is pushed down by the rubber piece 140, and the rubber piece 140 rotates while pressing the paper P against the reversing tray 16, so that the paper P is is sent in the direction of extraction.

Then, as shown in FIG. 17(e), the rear end side of the paper P is moved between the lower roller 66 of the transfer roller pair 66 and the pinch roller 1.
Send it between 18 and 18. After this, as shown in FIG. 17(f), the rubber piece 140 separates from the paper P, and as shown in FIG.
) and (h), it returns to the standby position. During this time, the operation of carrying out the preceding paper P from the reversing tray 16 and the carrying-in operation of the following paper P to the reversing tray 16 are performed in parallel.

In addition, according to the structure of the other embodiment in which the rubber piece 140 is attached, there is no need for a complicated gate means or a take-out means for moving the take-out roller up and down, making it possible to simplify the structure and reduce costs. .

Further, FIGS. 18 to 20 show still another embodiment of the main part of the present invention, in which the above-mentioned take-out roller 10
0 is replaced by a half-moon roller 150, and as shown in FIGS. 18 and 19, the flat portion 1 is
50a is positioned below to form a gap δ with the upper surface of the reversing tray 16.

In this case, as shown in FIG. 20(a), when the paper P is carried into the reversing tray 16, the flat portion 150a is positioned downward, and the paper enters the gap δ. And Fig. 20 (
As shown in b), when the trailing edge of the paper P passes the paper ejection switch 95 and turns from ON to OFF, the half-moon roller 1
50 starts the reversal. Then, as shown in FIG. 20(c), the half-moon roller 150 rotates a little further and stops when the rear end of the paper P leaves the pair of transport rollers 66. At this time, the gate 106 is in a lowered state.

Next, as shown in FIG. 20(e), the half-moon roller 15
0 starts forward rotation, and the rear end side of the paper P is transferred to the transfer roller pair 6.
6 between the lower roller 66 and the pinch roller 118. After that, as shown in FIG. 20(e), the half-moon roller 150 returns to the standby state and stops, and the gate 1
06 goes up and the subsequent paper P comes in. Then, as shown in FIG. 20(f), the operation of carrying out the preceding sheet P from the reversing tray 16 and the reversing tray 1 of the following sheet P are performed.
6 will be carried out in parallel. From then on,
The above operation will be repeated.

In addition, according to the configuration using this half-moon roller 150,
There is no need for a mechanism for moving the roller up and down so that it approaches and leaves the paper unlike in the case of a perfect-circle take-out roller, making it possible to simplify the configuration and reduce costs.

In addition, in the description of the other embodiments mentioned above, the same parts as those of the above-mentioned one embodiment are given the same reference numerals, and detailed explanations will be omitted.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist thereof.

[Effects of the Invention] As described above, the present invention provides an image forming apparatus equipped with an automatic double-sided image forming device, in which the automatic double-sided image forming device is provided with a reversing tray provided in the main body of the apparatus, and a reversing tray provided in the apparatus main body. a paper carrying means for feeding the paper that has passed through the image forming section and the fixing device into the tray; a taking out means for taking out the paper fed into the reversing tray by the paper carrying means from the rear end side; a stacker, a paper ejecting means for ejecting the paper taken out from the reversing tray by the ejecting means to the stacker, and a paper ejecting and transporting means for taking out the paper temporarily accumulated in the stacker and transporting it to the image forming section again. Because of this structure, there is no need to provide a long paper transport path consisting of a plurality of pairs of guide plates and pairs of transport rollers between the paper transport path leading to the fixing device via the image forming section and the stacker, as in the conventional case. , a large space can be secured above the stacker, and the reversing tray is located outside the main body of the device, making it easier to clear jams. At the same time, the space occupied by the automatic double-sided image forming device on the lower side of the paper transport path can be reduced, making it easier to form images. The device can be made smaller.

Further, the paper carrying-in means is configured to include a gate means and a pair of vertically movable transfer rollers provided at an exit portion of the gate means, and this pair of transfer rollers also serves as a feed roller of the paper carrying-out means. The number of parts in the paper transport section can be reduced, the configuration can be simplified and costs can be reduced, and jam handling can be facilitated.

Further, when the pair of vertically movable transport rollers that also serve as the feed rollers of the paper transport means reach the paper loading/unloading position with respect to the reversing tray, the driving force of the transport roller pair is transmitted through the driving force transmission system. Since the transmission is transmitted to the other feed rollers of the paper transport means, a dedicated drive source is not required, and since the feed rollers do not rotate except when necessary, noise is reduced.

[Brief explanation of the drawing]

1 to 14 show an embodiment of the present invention, in which FIG. 1 is a schematic perspective view showing the configuration of main parts, FIG. 2 is a schematic longitudinal sectional front view of the entire image forming apparatus, and FIG. FIG. 3 is a schematic perspective view showing the configuration of a paper carrying means for carrying paper into each bin of the sorter, FIG. 4 is a schematic front view, and FIG. 5 is a diagram showing the state in which paper is 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, FIG. 7 is a schematic perspective view, and FIG. 8 is a schematic perspective view showing the drive system. Figure 9 is an explanatory diagram showing the driving force connection/disconnection state of the drive system part, Figure 10 is an explanatory diagram showing the loading and unloading of paper into the reversing tray during automatic double-sided copying, and Figure 11 is the paper feed cassette. An explanatory diagram showing the flow of paper during automatic duplex copying for large-sized paper fed from a large-capacity paper feeder. Figure 12 shows the flow of paper during automatic duplex copying for small-sized paper fed from a large-capacity paper feeder. FIG. 13 is an illustration showing the loading and unloading of paper into the reversing tray during automatic double-sided copying, and FIG. 14 is an illustration showing the flow of paper during automatic double-sided copying for small-sized paper. , Fig. 15 to Fig. 17 show a first other embodiment of the main part of the present invention, Fig. 15 is a schematic front view, Fig. 16 is a schematic perspective view, and Fig. 17 is a schematic perspective view. An explanatory diagram showing the state of loading and unloading paper into the reversing tray;
18 to 20 show a second other embodiment of the main part of the present invention, in which FIG. 18 is a schematic front view, FIG. 19 is a schematic perspective view, and FIG. 20 is an inverted view. FIG. 4 is an explanatory diagram showing the state of paper being carried into and taken out of the paper tray. 1... Apparatus body, 2... Image forming process configuration means,
16... Reversing tray, 17... Automatic double-sided image forming device, 29... Image transfer section, 30... Fixing device, 33
... Paper carrying means, 65... Movable guide means, 66.
... Transfer roller pair, 90... Taking out means, 91... Stacker, 92... Paper carrying out means, 93... Paper taking out and conveying means, 116... Feed roller, 119... Driving force transmission Series, D...Manuscript, P...Paper. Applicant's Representative Patent Attorney Takehiko Suzue

Claims (3)

[Claims] (1) An image forming process configuration means is built into the main body of the apparatus, and an image corresponding to the document is formed on the paper sent to the image forming section of the image forming process configuration means, and then this image is attached to the paper by the fixing device. In an image forming apparatus that performs fixing, a reversing tray provided in the apparatus main body, a paper transporting means for feeding the paper passed through the fixing device into the reversing tray, and a paper transporting means that feeds the paper that has passed through the fixing device into the reversing tray; a take-out means for taking out sheets from the rear end side; a stacker provided in the apparatus main body; a paper take-out means for transporting the sheets taken out from the reversing tray by the take-out means to the stacker; 1. An image forming apparatus characterized in that an automatic double-sided image forming apparatus is attached thereto, comprising a paper take-out and transport means for taking out the paper and transporting the paper to the image transfer section again. (2) The paper carrying means consists of a movable guide means and a pair of vertically movable transfer rollers provided at the exit of the movable guide means, and this pair of transfer rollers also serves as the feed roller of the paper carrying means. The image forming apparatus according to claim 1. (3) When the vertically movable transport roller pair, which also serves as the feed roller of the paper transport means, reaches the paper loading/unloading position with respect to the reversing tray, the driving force of the transport roller pair is transferred to the transport roller pair through the driving force transmission system. 3. The image forming apparatus according to claim 2, wherein the image forming apparatus is configured to transmit the information to another feed roller of the paper conveyance means.