JPH069159A - Image forming device equipped with paper refeeding means - Google Patents

Abstract

PURPOSE:To prevent sheet members from being stained when the sheet members are fed again out of an intermediate tray at the time of a double surface copying mode or a multi-copying mode. CONSTITUTION:In the device, an accumulation housing section 144 acting as an intermediate tray is so constituted as to be raised up almost vertically, the inclination of the aforesaid section is changed correspondingly when each sheet is housed in, and when each sheet is fed again. The sheets are loaded in order from the upper portion of the intermediate tray, and the sheets are fed in while the upper side of each sheet is being separated by a separation and a feeding means 122 and 123.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet refeeding apparatus, and more particularly, a sheet refeeding apparatus provided in an image forming apparatus such as a copying machine, a printer or a facsimile, which is capable of double-sided image formation and multiple image formation. Regarding

[0002]

2. Description of the Related Art FIG. 10 shows a conventional example of an image forming apparatus (copier) capable of double-sided image formation and multiple image formation.

In this image forming apparatus, the sheet material S fed from each of the paper decks 1, 2 and 3 is conveyed to the photosensitive drum 5 on which the same image as the original is formed by a predetermined electrophotographic process. Then, after the toner image (latent image) on the photosensitive drum 5 is transferred here, the toner image is conveyed to a fixing device 6 for fixing the toner image, and passes through this to form a first surface (or a first time) image. To finish.

When the single-sided copy mode is selected, the sheet material S after the image formation passes through the upper side of the flapper 7 shown by the solid line and advances in the direction of arrow A by the external sheet discharge roller pair 9 as it is. The paper is discharged onto the outside paper discharge tray 10.

When the double-sided copy mode is selected, the flapper 7 is in the state shown by the broken line, and the sheet material S after image formation passes through the right side portion of the flapper 7 by the pair of inner paper discharge rollers 11. Proceed in the direction of arrow B, and pass 1
Sent to 2. Then, after passing through the flapper 13 shown by the solid line, it enters the reversing path 15. Then, when the trailing edge of the sheet material S has completely passed the flapper 13, the reverse path roller pair 16 is reversed. As a result, the sheet material S advances in the direction of arrow C, is inverted, is guided to the flapper 13, and is guided to the refeed tray (intermediate tray) 19 by a predetermined pair of discharge rollers 17 of the sheet material conveying unit 31, as shown in FIG. It is loaded and stored in.

The flapper 13 does not resist the movement in the direction of arrow B in which the sheet material S enters the reversing path 15, but resists the movement in the direction of arrow C after being reversed. Then, the sheet material S is sent to the sheet material conveying unit 31.

When the multiple copy mode is selected, the flapper 13 is switched to the state shown by the broken line by a solenoid (not shown), and the sheet material S sent to the vertical path 12 is transferred to the reverse path 15. The sheet is sent to the sheet material conveying unit 31 as it is without being switched back. Sheet material S
Are stacked and stored on the re-feed tray 19 by a predetermined pair of discharge rollers 17.

As shown in FIG. 11, the sheet refeed tray 19 has a delivery roller for rotating in the direction of the arrow and sequentially delivering the sheet materials S stacked on the sheet refeed tray 19 from the lowermost sheet material S. 20 and a pair of paper feed rollers 21 for separating the sheet material S fed by the feed roller 20 in the arrow direction and feeding the sheet material S one by one. The refeed tray 19, the delivery roller 20, and the pair of paper feed rollers 21 form a refeed device 30A of the image forming apparatus.
Is configured.

When the sheet material S is stacked on the re-feed tray 19, the delivery roller 20 needs to be retracted below the re-feed tray 19 so as not to become a resistor.
Further, when the sheet materials S stacked on the re-feed tray 19 are sent out, it is necessary to apply a predetermined conveying force.
For this reason, a so-called D-cut roller, in which a part of the outer peripheral surface is cut out in a substantially horizontal shape, is usually used as the delivery roller 20. When the D-cut roller 20 is stopped so that the cut surface 20A is substantially horizontal on the upper side, the D-cut roller 20 is retracted below the refeed tray 19.

The paper feed roller pair 21 comprises a paper feed roller 22 and a separate roller 23 driven via a torque limiter (not shown). Then, when one sheet material S is sent from the delivery roller 20, the sheet material S is fed as it is, and when a plurality of sheet materials S are sent, the separation roller 23 rotating in the direction of the broken line arrow frictionally separates the sheet material S into one sheet. Only feed. The sheet material S fed by the paper feed roller pair 21 is sent to the photosensitive drum 5, and the second surface (or second time) image formation is performed.

The sheet material conveying section 31 for conveying the sheet material S onto the re-feeding tray 19 includes a sheet material upper guide 25, a plurality of sheet material lower guides 26, a plurality of flappers 27, and a plurality of flapper 27. And a pair of discharge rollers 17 of.

As described above, the sheet material conveying section 31 is provided with the plurality of flappers 27 and the discharge roller pairs 17,
There are several sizes of the sheet material S. For the small size sheet material S, the flight of the sheet material S is disturbed by the presence of air when the flight distance to the stacking position on the re-feed tray 19 becomes long, and the re-feed tray This is because the stacking failure on 19 causes a trouble in the image formation on the second side (or the second time). Therefore, it is necessary to provide a plurality of outlets for minimizing the flight distance and reducing the influence of disturbance according to the size of the sheet material S. That is, as the size of the sheet material S is smaller, the sheet material S is discharged from the discharge roller pair 17 closer to the flapper 13.

In FIG. 11, reference numeral 29 is a side regulating plate, and reference numeral 32 is a sheet material pressing plate. Side regulation plate 2
The sheet material S 9 is reciprocally moved by a drive source (not shown) in a direction perpendicular to the conveying direction of the sheet material S and discharged.
And the function of adjusting the loading state on the re-feed tray 19. In addition, the sheet material pressing plate 32
Has a function of moving the sheet materials S stacked on the re-feeding tray 19 in the direction of the arrow by a solenoid (not shown) and pressing the sheet materials S to give the sheet material S a pressure necessary for conveyance.

As described above, the separating method of the re-feeding device is as follows.
This is called the lower separation method because the paper is re-fed from the lowest sheet of the stacked sheets. Since the stacking operation and the re-feeding operation can be performed at the same time, the productivity of the copying machine is extremely high, and the copying machine is preferably used in a high-speed copying machine.

[0015]

However, in the above-mentioned conventional example, in the case of double-sided image formation, since the paper is re-fed from the lowest position of the stacked sheets, the image forming surface of the first side is set as the upper surface and the sheets are stacked on the tray. To be done. When the delivery roller operates in this state, the entire stacked sheets are conveyed to the pair of sheet feeding rollers located downstream. The paper feed roller pair is composed of a paper feed roller that rotates only in the paper feed direction and a separate roller that rotates in the opposite direction to the conveyance direction via the torque limiter and frictionally separates.
Multiple sheet materials enter the nip of the pair of paper feed rollers, and the lowest paper is fed and conveyed, while the sheet material positioned above the sheet material stops at the nip portion, and the sheet material that is in the process of being fed. Will be rubbed with.

At this time, the first image forming surface of the sheet material in the middle of feeding is the upper surface, and at the leading end of the sheet material at rest,
Since the toner constantly contacts and rubs, the toner dislocates and contaminates the leading end of the sheet material.

[0017]

According to the present invention, there is provided means for accommodating a plurality of sheet materials in the sheet material reversal portion, which is also seen in the prior art, and capable of re-feeding. Further, a swinging fulcrum is provided above the reversing portion to load the sheet material.
And the second position for re-feeding the sheet material to allow swinging, so that
The re-feeding operation in the upper separation mode becomes possible. for that reason,
By eliminating the transfer of dirt to the residual sheet material during sheet re-feeding, it has become possible to achieve high copy production efficiency.

According to the second aspect of the present invention, the reversing unit found in the conventional example is re-fed and arranged substantially vertically, and the storage paper is pressed in one direction by the pressing means, and the subsequent sheet material is inserted. In addition to providing a space where it can be stored, and by arranging extrusion rollers on opposite sides of the pressing means, it is possible to eliminate the transfer of dirt to the residual sheet material by the sheet material in the process of re-feeding, resulting in high copy productivity. It was made possible.

[0019]

1 is a sectional view of a first embodiment of the present invention, and FIG. 2 is an enlarged view of a reversal storage portion. It should be noted that the description of the functions and the like of the constituting means that are the same as those of the conventional example will not be given.

Reference numeral 140 denotes a document circulation device which, when a document is placed on the document stacking tray 140-1 and copying is started, separates one by one from the bottom sheet of the stacked document and sets it on the plantain 140 of the image forming apparatus. Stop the transportation at the position. The sheet material S fed from each of the paper decks 1, 2 and 3 is conveyed to the photosensitive drum 5 on which the same image as the original is formed by a predetermined electrophotographic process. After the toner image on the photosensitive drum 5 is transferred, the sheet material S is transported to the fixing device 6 via the transport unit 42. After passing through the fixing device 6, the sheet material S is ejected to the outside of the machine through the paper ejection unit 43. On the other hand, the first
If a so-called double-sided copy mode in which the second image is formed on the back side of the surface, or a so-called multiplex copy mode in which the second image is copied on the same side as the first side, the sheet is selected. The material S is operated by operating the flapper 7 in the paper discharge section 43, guided to the first transport section 12, and circulated in the machine by using the stacking and storing device 144 described below. Reference numeral 113 denotes the first transport unit 12 and the loading / storing device 14.
4 is a sheet material conveying direction switching device located at the confluence of the second conveying portion 145. 113-1 is a solenoid S-1
Is a first flapper that is switched by. 113-
Reference numerals 2 and 113-3 are springs 113-4, and are second and third flappers that are brought into contact with each other in a light pressure in a solid line state.
The sheet material S that rotates in the broken line state with respect to the sheet material S transported from the first transport portion 12 direction, but runs in the reverse direction from the second transport portion 145 direction, and the stacking storage device. With respect to the sheet material S conveyed from 144, the solid line state is maintained and the sheet material S is guided in the target direction.

Therefore, when the double-sided copy mode is performed,
The solenoid SL-1 of the first flapper 113-1 is not magnetized, and the sheet material S is transferred from the first transport unit 12 to the storage device 1.
After heading to 44, the vehicle runs in the reverse direction and is transported to the second transport unit 145, so that it is possible to turn the sheet upside down.

In the multi-copy mode, the solenoid SL-1 of the first flapper 113-1 changes to the broken line state when energized, so that the sheet material S is sent from the first carrying section 12 to the second carrying section 145. To be The second transport unit 145 is provided with a plurality of transport rollers 146 managed by a plurality of drive systems, and the sheet material S can be transported and stopped freely.
The sheet material S sent to the second transport unit 145 is run backward when the trailing edge of the sheet material S passes through the third flapper 113-3,
The sheet material S that has been stored in the stacking storage device 144 and has been stored is transported to the second transport unit 145.
The state where the front-back relationship is maintained is maintained.

On the upper part of the stacking / storing device 144, the sheet feeding roller 122 capable of forward and reverse rotation and the sheet material S are stacked / storing device 1.
The separating roller 123 that rotates via the torque limiter is arranged only in the direction of 44, and when the sheet material S is conveyed in the stacking and accommodating device 144 direction, it acts as a conveying roller and also as a stacking and accommodating device 144. When it is sent out from the sheet, it has both functions as a roller pair for separating and feeding the sheet material S one by one.

FIG. 3 shows a schematic diagram of driving the apparatus. The loading / storing device 144 and a part of the transport rollers 146-1 of the second transport unit 145 are driven by the same forward / reverse rotation motor M1 (FIG. 38b)). Another portion 1 of the second transport unit 145
46-2 is a separate drive (FIG. 3C), the reason for which will be described later. In the middle of the drive system reaching the paper feed roller 122,
An electromagnetic clutch CL-1 is provided to form a sheet interval and drive control is performed. The forward / reverse rotation of the paper feed roller 122 depends on the rotation direction of the motor M1. On the other hand, an electromagnetic clutch CL-2 is provided in the drive system of the separation roller 123, but when the sheet material S is conveyed to the stacking storage section 144, it is made a driven roller without drive input. Also,
A torque limiter TL-1 is provided on the shaft,
A direction in which the sheet material S is sent to the stacking and storing section 144 via the torque limiter TL-1, that is, the stacking and storing section 1
The drive is transmitted so as to rotate only in the separating direction at the time of being fed from 44, and friction separation at the time of re-feeding is possible.

The conveying speed of the motor M1 applied to the sheet material must be set to 1.2 times or more the image forming speed. This is the operation of feeding the sheet material S once to the stacking storage section 144 and immediately transporting it to the second transport section 145 when the preceding sheet feeding in the double-sided copy mode described later is performed, and the sheet material S in the multiple copy mode. S is the second transport unit 1
It is sent to 45 once and reversely run immediately, and the loading storage section 144
This is because the operation of transporting the sheet to the sheet must be completed before the leading edge of the succeeding sheet material S arrives. For example, an image forming speed of 320 mm / sec, A per minute
When the number of copies of four originals is 50, the distance between the trailing edge and the leading edge of the sheet material S, that is, the so-called sheet interval, is 177.6 mm. Therefore, during this period, the conveyance speed for accommodating one sheet material S is about 1.2 times. In addition to this, the stop time, start-up time, and electromagnetic clutch C of the motor M-1, which is an electric component,
Considering the loss of the connection time of L-1 and CL-2, etc., a speed of 1.4 times or more is usually required.

Reference numeral 148 denotes a stacking tray, which aligns the stacking positions of the sheet materials S with the leading end regulation plate 149 and the left and right regulation plates 1.
29 and a plurality of sheet material pressing flappers 150. The tip regulation plate 149 and the left and right regulation plate 129 are provided with a stepping motor (not shown) and a sensor serving as an index for moving to an accurate position on each side, and are connected by a drive transmission means such as the wire 151. ,
Move to the proper position on the selected sheet material.

The sheet material pressing flapper 150 is provided with its swinging fulcrum 151 in the direction in which the sheet material S enters, and is provided with a light pressure spring 152, so that the sheet material S does not resist the entry of the sheet material S and is stacked. The curling of the formed sheet material is suppressed and the stacking of the connected sheet material is not affected.

Reference numeral 153 denotes a movable tray, which is connected to the stacking tray 148 at a swing fulcrum 154 at the bottom of the apparatus. In the movable tray 153, the eccentric cam 155 rotates according to the movements of the motor M0 and the half rotation clutch in the device,
The state becomes close to the stacking tray 148 (see FIG. 4B). On the movable tray 153, the above-mentioned motor is used as a drive source, and the feed roller 120 that rotates via the input shaft 156 and the belt 157 and the solenoid that brings the feed roller 120 into contact with the stacked sheet material are centered around the input shaft 156. A separation spring 158 is provided for separating the SL-2 from the SL-2 when energization is OFF.

Further, the swing fulcrum 159 of the loading / storing device 144
Is provided on the upper part of the device. A motor M3 for moving the device around the swing fulcrum 159, a timing belt 160, pulleys 161, 162, and sensors C1, C2 for detecting the condition of the device are provided in the lower part of the device. That is, the sensor C1 detects the state of FIG. 2, that is, the state in which the sheet material is stored and stacked, and the sensor C2 detects the state of FIG.
This is a state where the sheet material shown in (c) is being re-fed.

The reason for using such a sheet material stacking and storing device 144 is that the image forming surface of the first side is turned up and the side of the delivery roller 120 is set when the apparatus is swung in the duplex copying mode. Therefore, at the time of re-feeding, even if a plurality of sheet materials are fed into the nip of the pair of feeding / separating rollers 121, the unimaged surface of the fed sheet material may come into contact with the leading edge of the sheet material to be separated. This is because the dislocation adhesion of the toner does not occur. In addition, since the stacks are arranged substantially vertically, power is applied to the sheet materials, so that the chances of a plurality of sheet materials reaching the nip of the pair of feeding / separating rollers 121 are reduced. Can be mentioned.

Based on the above configuration, a basic operation of conveying a sheet material will be described with reference to FIGS. 2 and 4.

After the image formation on the first side of the sheet material S is completed, the sheet material S is fed through the first transport section 12 and the sheet material transport direction switching device 13. Solenoid S of the first flapper 113-1
L-1 need not operate. Also, the second flapper 1
Since 13-2 also does not become a resistance against the sheet material, it does not affect the transportability. The paper feed roller 122 rotates in the transport direction (CW in the figure). The separation roller 123 does not energize the electromagnetic clutch CL-2 and functions as a driven roller. The sheet material S is thus paired with the sheet feeding / separating roller 1.
By means of 21, the sheets are successively fed into the loading / storing device 144 stopped at the positions shown in FIG. 2 (FIG. 4A).

The sheet material pressing flapper 150 on the stacking tray 148 presses the sheet material S to the movable tray 153 side, presses the curl generated in the sheet material, and makes it easy for the continuously fed sheet material to enter. Acts like

When the storage of all the sheet materials is completed, the eccentric cam 155 makes a half rotation, the movable tray 153 swings, and moves so as to be parallel to the stacking tray 148 (FIG. 4B).

Next, the motor M3 moves to load and store the device 14.
4 is rocked until the sensor C2 detects it, and the preparation for the re-feeding operation is completed. Refeed is solenoid SL-2
Is operated to bring the delivery roller 120 into contact with the uppermost sheet of the sheet material S, and thereafter, the delivery roller 120, the paper feed roller 121, and the separation roller 122 are all rotated counterclockwise. The sheet materials S are separated one by one and sent to the second transport unit 145, where they are transported for image formation on the second surface. Swing of the rotating tray 153,
The abutting operation of the delivery roller 120 may be performed at the same time while the stacking device is rocking, and it is not particularly necessary to follow the order as described above.

Next, a basic conveyance mode of the sheet material S in the multiple copy mode will be described with reference to FIG. The operation of the loading / storing device 144 is basically the same as in the double-sided copy mode described above.

The second flapper of the sheet material conveying direction switching device 13 moves by the operation of the solenoid SL-1 and sends the sheet material S from the first conveying portion 12 to the second conveying portion 145 (FIG. 5 (a)). . At the moment when the trailing edge of the sheet material passes through the third flapper 113-3, the rotation of the conveying roller pair 146-1 is reversed and the sheet material is sent to the stacking and storing device 144 (FIG. 5B). 3 flapper 113-
3 does not become a resistance because the spring 113-4 restores the sheet material S to the position where it is guided. The drive method of the pair of paper feed / separation rollers 121 and the movable pattern of the stacking / storing device 144 are the same as described above.

However, in the operation described above,
After all the sheet materials are stored in the stacking and storing device, sheet re-feeding is started, which requires a sheet pass of the second sheet transport section and a sheet transport time, which is an efficient disadvantage.

Below, a description will be given of a case where this time is filled up and the efficiency of the copying operation is improved. In FIG. 6, a plurality of sheet materials S positioned at the beginning in the double-sided copy mode are
A method of shortening the time required for the leading sheet material to reach the drum by causing the transporting unit 145 to carry it in advance and stopping and waiting will be described.

The sheet material S conveyed from the first conveying section 12
Is guided in the direction of the loading / storing device 144 (see FIG. 6).
(A)). At this time, the sheet material is not completely stored in the apparatus, but the rear end of the sheet material S is located at the second flapper 113.
The rotation direction of the paper feed roller 122 is reversed at the moment of passing through -2. Since one sheet material is in the pinching and conveying state,
It is not necessary to drive input to the separation roller 123, and it may be handled as a driven roller. Also, the second flapper 1
Since the spring 13-4 restores the sheet material 13-2 at the moment when the sheet material comes off, it smoothly guides the sheet material S to the second conveyance unit even when the sheet material S runs backward (FIG. 6B). As shown in FIG. 3, if the pair of transport rollers of the second transport unit 145 are independently driven, the sheet material to be transported in advance can be stopped and waited in the transport unit. All the remaining sheet materials are stored in the stacking storage device, following the preceding sheet material,
A paper re-feeding operation may be performed (FIG. 6 (c)).

FIG. 7 shows the operation of the preceding conveyance in the multiple copy mode. Sheet material S transported from the first transport unit 12
Is operated by the first flapper 113-1,
It is sent to the transport unit 145 (FIG. 7A). At this time, the sheet material is not run backward, but is sent to the conveyance roller pair 146-2, which is managed by another drive system as it is, and then stopped and stands by. All the subsequent sheet materials move in the same manner as in the normal multi-copy mode, and then are stored in the stack storage section 144 (see FIG. 7).
(B)), the sheet refeeding operation is performed following the preceding sheet material (FIG. 7C).

As described above, the preceding sheet material is fed after the sheet material is first fed to the second conveying portion 145 closer to the drum and stopped and waited for, the image formation for the first side is completed, and the document replacement is completed. Therefore, it can be said that it is more effective because the time can be shortened by starting the image formation on the second surface.

FIG. 8 shows another method for improving the efficiency of the multiple copy mode. This is because the plurality of sheet materials are not stored in the stacking and storing device from the rearmost side of the image formation on the first surface, but are directly transported from the first transport unit 12 to the second transport unit 145, and the storage time of the sheet materials is shortened. This is the idea. The preceding sheet materials S are sequentially stored in the stacking and storing device 144. This procedure is the same as a general operation procedure (FIG. 8A). The maximum number of sheet materials that can be arranged on the paper path is calculated backward from the rearmost side, and the number of sheet materials is not stored in the stacking storage device but is directly transported from the first transport unit 12 onto the second transport unit ( FIG. 8B). The sheet material SN at the tail end (ordinarily the sheet material that finally enters the storage device 144) may be sent out from the stack storage device 144 while forming a predetermined sheet interval after entering the second transport unit 12. (FIG.8 (c)).

Needless to say, the present invention is not limited to this embodiment.

(Other Embodiments) FIG. 9 shows a second embodiment of the present invention in which a multi-sided copy mode from a large number of originals is performed.
In particular, a method aiming at copy efficiency (hereinafter referred to as skip mode) will be described.

This is the first conveyance section in the image forming apparatus.
Considering the total length of the circulation path of the sheet material represented by the transport section, the reversal storage section, the second transport section, and the like, and the number of sheet materials S lined up there, when the number of copies equal to or more than the specified number is selected, The optimum method of the sequence of the above-described embodiment may be adopted. However, if the specified number of copies or less is selected, the sheet material circulates in the machine and stands by while returning to the photosensitive drum. However, the result is not favorable in terms of efficiency.

The second embodiment is a method in which this point is improved, and the description of the same parts as those of the first embodiment will be omitted because it is redundant. When a plurality of originals, for example, eight originals are set in the original circulating device 140, the original circulating device 140 counts the number of originals from the bottommost sheet, conveys them onto the platen 41, and reads every other original. The sheet material S is fed from the respective decks 1, 2 and 3 and image-formed in the order of page 8, page 6, page 4 and page 2, and the state of FIG. 9D (detected by the sensor C1 shown in FIG. 2) is detected. 9C is loaded in the stacking / storing device 144 that is on standby in the state shown in FIG. The loading / storing device 144 has the same structure as that of the first embodiment (FIG. 2). After the circulation of the original document is completed, the second circulation conveyance is started. After the second circulation, the original document is conveyed onto the platen according to the stacking order. At this time, each deck 1, 2, 3
Then, the sheet material is alternately guided to the photosensitive drum from the stacking / storing device 144 that has swung in the state of FIG. 9B.

That is, the sheet material corresponding to the 8th, 6th, 4th, and 2nd sheets of the original document is
The sheet materials corresponding to the fifth, third, and first sheets are achieved by sending out from the stacking and storing device. In the paper discharge unit 43, the sheet material having the images formed on the front and back sides is discharged outside the machine, and the sheet material having the image formed on only one side branches to the first transport unit 12 and is sent to the stacking and storing device 144. At this time, the stacking / storing device 144 needs to be returned to the state shown in FIG. 9A, so it is necessary to control so that the sheet material is stored and the sheet is re-fed alternately. In general, the purpose is achieved if the paper is re-fed between the storages. The above operation is repeated.

In the case of the last part, contrary to the first circulation, only the unformed 7th, 5th, 3rd and 1st originals are sent to the platen 41, and the sheet material in the stacking and storing device 144 is re-fed. do it. In this mode, the number of originals is worrisome, but the image is not formed on the first sheet material to be re-fed from the stacking storage section, and the image is formed on the second and subsequent sheets. If the reverse sheet discharge function is incorporated in the first transport unit 12, it is possible to correct the page order when discharged outside the machine.

In the above, the case of the skip mode has been shown as a method of increasing the production efficiency in the case of a small number of parts. Also, the first
Further efficiency can be achieved by combining with the double-sided preceding paper feeding mode described in the embodiment. Needless to say, the present invention is not limited to the configuration of this embodiment.

Next, an embodiment of the second invention will be described with reference to FIGS. The description of the same members as those of the first embodiment of the invention of FIGS. 1 to 9 will be omitted.

The sheet push-up flapper 250 is provided with a swing fulcrum 251 in the sheet material advancing direction, and has solenoids SL-2, SL-3, SL-4 dedicated to each individual, so that independent operation is possible. Has become. Further, the shape of the flapper itself has a substantially "doglegged" shape in order to effectively push up the sheet material during operation and thus to widen the contact area. Reference numeral 52 denotes a movable tray, and the eccentric cam 155 rotates in accordance with the movement of the half-rotation clutch 253 arranged in the drive system, and the configuration of FIG.
It will be in a state close to. In the above configuration, the image forming surface in the double-sided copy mode storage is stacked so as to face the movable tray 153 side.

The basic conveyance of the sheet material S in the double-sided copying mode and the multiplex copying mode having the above-described structure will be described.

FIG. 15 shows a standard double-sided copy mode.
The sheet material S is transferred from the first transport unit 12 to the first flapper 11
3-1 Guided by the second flapper 113-2,
The paper is conveyed to the reversal storage unit 144. The paper feed roller 122 is
It rotates in the transport direction (CW in the figure). Separation roller 123
Causes the electromagnetic clutch CL-2 to be energized and not to be driven and to function as a driven roller. Each time one sheet material S is stored, the push-up flapper 250 is operated,
Pushed up to the movable tray 153 side, the succeeding sheet material S,
Standby to insert and stack in the lower layer (Fig. 15 above)
(A)). When the sheet material S is fed, just before the leading edge of the sheet material S reaches, the push-up flapper 2 near the entrance is pushed.
The sheet 50 is retracted (FIG. 15B), and the sheet material S is fed between the sheet material S previously stacked and the stack tray 148 (FIG. 15B). After accommodating all the sheet materials, the movable tray 153 swings, and the sheet material S moves so as not to buckle. In response to the movement of the solenoid SL-5, the delivery roller 120 comes into contact with the uppermost sheet of the sheet material S, and the sheet refeed operation is started. Since the feeding roller 120, the paper feeding roller 122, and the separating roller 123 are driven as described above, the sheet material S is separated one by one, and the second conveying unit 1
45 (FIG. 15C).

FIG. 16 shows a standard multiplex copy mode.
The first flapper 113-1 is operated and the sheet material S is once sent from the first transport unit 12 to the second transport unit 145 (FIG. 16A). At the moment when the rear end of the sheet material S passes through the third flapper 133, the rotation direction of the pair of transport rollers 146-1 of the second transport unit 145 is reversed, and the reverse storage unit 14 is rotated.
4 (Fig. 16 (b)). The method of moving the stacked sheets and the sheet re-feeding operation during storage are the same as those described above (FIG. 16).
(C)).

FIG. 17 shows a method of shortening the time required to form an image on the second side in the double-sided copying mode, in which the plurality of sheet materials S located at the beginning are stopped and waited by the second conveying section 145. Sheet material S transported from the first transport unit 12
Is sent to the reversal storage unit 144 (FIG. 6A). The sheet material S is not completely stacked on the stacking tray 148, but the sheet feeding roller 122 is rotated in the reverse direction at the moment when the trailing edge of the sheet material S passes through the second flapper 113-2. At this time, 1
The separation roller 123 is in a state of sandwiching a sheet material.
Since it is not necessary to input the rotational force in the separating direction, it is sufficient to set the driven state without inputting the driving force. The second flapper 113-2 is restored by the force of the spring 113-4 at the moment when the sheet material S comes off, so that the second flapper 113-2 smoothly guides the sheet material S to the second transport portion 145 with respect to the reverse running. As shown in FIG. 14, since the second transport unit 145 has an independent drive system, it is possible to stop and wait the sheet material previously transported. By stopping in this way, it is possible to shorten the transport time required for this transport length. The rest of the sheet material S is all reversed in the storage section 144.
Needless to say to store in.

FIG. 18 shows the case where the preceding sheet material in the multiplex copy mode is on standby. The sheet material S conveyed from the first conveyor 12 is the operated first flapper 113-1.
Thus, after being sent to the second transport unit 145, the preceding sheet material S does not run backward, but is sent to the transport roller pair 146-2 that is managed by another drive as it is and stands by (FIG. 1).
8 (a) → (b)). All the succeeding sheet materials S are stored in the reversal storage section 144 (FIG. 18C). After the storage of all the sheet materials is completed, the image formation is performed in order from the sheet material S on the second transport unit 145, whereby the time required for the length of the second transport unit can be shortened.

FIG. 19 shows another method of improving the efficiency of the multiple copy mode. This is because the plurality of sheet materials are not stored in the reverse storage portion from the rearmost side of the image formation on the first side but are directly transported from the first transport portion to the second transport portion, and the time for storing the sheet material is shortened. Describe the method to achieve. In this method, the preceding sheet materials S are sequentially stored in the reversal storage section 144, and the maximum number of sheet materials that can be arranged on the paper path are not stored from the middle but are conveyed on the second conveyance section. Is. Needless to say, after the rearmost sheet material S has entered the second transport section 145, the sheet material S is sent out from the reversal storage section 144 while forming a predetermined sheet interval.

FIG. 20 shows, as another embodiment, a method (hereinafter referred to as a skip mode) in which the copying efficiency is particularly aimed at when the small-sided two-sided copying mode is performed from a large number of originals.

This is the first conveyance unit in the image forming apparatus.
Considering the total length of the circulation path of the sheet material represented by the transport section, the reversal storage section, the second transport section, and the like, and the number of sheet materials S lined up there, when the number of copies equal to or more than the specified number is selected, The optimum method of the sequence of the above-described embodiment may be adopted. However, if the specified number of copies or less is selected, the sheet material circulates in the machine and stands by while returning to the photosensitive drum. However, the result is not favorable in terms of efficiency. The second embodiment is a method in which this point is improved, and the description of the same parts as those of the first embodiment will be omitted because it is redundant.

When a plurality of originals, for example, eight originals are set in the original circulating device 140, the original circulating device 140
Feeds every other sheet onto the platen 41 while counting the number of originals from the bottom sheet. Sheet material S is for each deck 1,
Paper is fed from Nos. 2 and 3, and images are formed in the order of page 8, page 6, page 2 and page 2, and the sheets are stored and stacked in the reverse storage unit 144. The reversal storage unit 144 has the same configuration as that of the previous embodiment, and the push-up flapper 250 pushes up the sheet material S and the succeeding sheet material S with the preceding sheet material and the stacking tray 1.
2 for inserting and loading between 48 (FIG. 20- (a)).
0- (c)) are stored in the order found. After the circulation of the original document is completed, the second circulation conveyance is started. After the second circulation, the original document is conveyed onto the platen according to the stacking order.
At this time, the decks 1, 2, 3 and the reversal storage section 144
The sheet materials are alternately guided to the photosensitive drum.

That is, the sheet material S, which corresponds to the eighth, sixth, fourth, and second sheets of the original document, is transferred from each deck 1, 2, and 3 to the original sheet 7,
The sheet materials S corresponding to the fifth, third, and first sheets are inverted storage units 144.
It is achieved by sending out (Fig. 20 (b),
(D), (e)), in the paper discharge unit 43 (tray 110),
The sheet material S on which images are formed on the front and back is discharged to the outside of the machine, and the sheet material S on which only one side is imaged is branched to the first transport unit 12,
The sheet is sent to the reversal storage section 144, and stacked and stored according to the same procedure as described above. The above operation is repeated. In the case of the last part, contrary to the first order,
The third and first originals may be fed onto the platen 141 and re-fed from the reversal storage section 144. Further, in this mode, it is worried that the number of originals is odd, but the image is not formed on the first sheet material S re-fed from the reversal storage section 144, and the image is formed on the second and subsequent sheets. If the reverse paper ejection function is included in the first transport unit 12 while performing the formation,
It is possible to correctly eject the page order when ejecting from the machine.

Further, it is necessary to store the sheet material S in the reversal storage section 144 during the re-feeding operation. In general, the purpose is achieved if the paper is re-fed between the storages.

Further, if the combination with the double-sided preceding paper feeding mode described in the first embodiment is attempted, further efficiency is achieved. Needless to say, the present invention is not limited to this embodiment.

FIG. 21 shows still another embodiment. The present embodiment is a method in which the insertion and storage of the sheet material into the reversal storage portion is smoothly performed, and the member means described in the first embodiment will not be particularly described with respect to overlapping members.

In this embodiment, an air nozzle 260 is provided above the reversal storage part 144 so as to blow out air toward the front end of the sheet material S to be stacked. This is because the sheet materials S previously stacked in the reversal storage section 144 are retracted by the push-up flapper 250, and the stack tray 148 is then loaded.
It is intended to avoid hindering the storage of the subsequent sheet material S that is being inserted and is being inserted, or blowing air between the previously loaded sheet material S and the stacking tray 148 only during storage, A space is secured, and the sheet material S to be connected can easily enter. When re-feeding, air may not be blown, so air may not be blown out. The air blowing angle, the flow velocity, and the air blowing amount cannot be constantly determined, but are determined by the configuration of the device. It goes without saying that the invention is not limited to the embodiments described above.

[0067]

As described above, the reversing portion found in the conventional machine can simultaneously accommodate a plurality of sheet materials, and
By changing the stacking position and re-feeding position of sheet materials and changing to a device that re-feeds sheets according to the storage order, contamination due to rubbing between sheet materials can be prevented and copy efficiency in all modes can be improved at the same time. Has the effect of

[Brief description of drawings]

FIG. 1 is a front sectional view showing an entire copying machine to which the present invention (first) is applied.

FIG. 2 is a front sectional view similarly showing an enlarged main part.

FIG. 3 is a schematic view showing a drive mechanism of a main part of the same.

FIG. 4 is a diagram showing a movement in the double-sided copy mode.

FIG. 5 is a diagram showing the movement in the multiple copy mode.

FIG. 6 is a diagram showing the movement of the second example in the double-sided copy mode.

FIG. 7 is a diagram showing the movement of the second example in the multiple copy mode.

FIG. 8 is a diagram showing the movement of the third example in the multiple copy mode.

FIG. 9 is a diagram showing the movement of the third example (skip mode) in the double-sided copy mode.

FIG. 10 is a front sectional view showing a conventional example.

FIG. 11 is a front sectional view showing details of a conventional example.

FIG. 12 is a front sectional view showing an entire copying machine to which the present invention (second) is applied.

FIG. 13 is a front cross-sectional view showing an enlarged main portion of the same.

FIG. 14 is a schematic view showing a drive mechanism of the main part of the same.

FIG. 15 is a diagram showing the movement in the double-sided copy mode.

FIG. 16 is a diagram showing a movement in the multiple copy mode.

FIG. 17 is a diagram showing the movement of the second example in the double-sided copy mode.

FIG. 18 is a diagram showing the movement of the second example in the multiple copy mode.

FIG. 19 is a diagram showing the movement of the third example in the multiple copy mode.

FIG. 20 is a diagram showing the movement of the third example (skip mode) in the double-sided copy mode.

FIG. 21 is a front sectional view showing another example of the main part of the same.

[Explanation of symbols]

 12 1st conveyance part 144 Stacking storage part 145 2nd conveyance part 113 Switching means 155 Swinging means 122,123 Paper feeding means 250 Pressing means

Claims (8)

[Claims] 1. In an image forming apparatus that circulates and forms a plurality of images on the front and back surfaces of a sheet material or on the same surface, a first transport unit that transports the sheet material, and a first transport unit that transports the sheet material. And a plurality of conveying roller pairs for conveying the sheet material fed from the first conveying section or the stacking and accommodating section to the image forming section. A second transport unit, a switching unit for switching the transport direction of the sheet material arranged in the first transport unit, the stack storage unit, and a confluence of the second transport units, and the stack storage unit can be swung. Support means, a means for swinging between a first position when the sheet material is loaded in the stacking storage part and a second position when the sheet material is sent out, and one sheet material in the stacking storage part Refeeding means, characterized in that it comprises: An image forming apparatus provided. 2. The sheet feeding device includes a driving unit rotatable in two directions, a sheet feeding roller having a drive transmission control unit, and a drive transmission control unit, and is rotated at a certain value or more. When a torque is generated, it is composed of a separation roller having a trick limit means in which the drive is not transmitted regardless of the driving direction. When the sheet material is conveyed in the stacking and storing section direction,
When only one sheet material is sandwiched and is carried out from the stacking storage section, the drive of the sheet feeding roller is transmitted, the drive of the separating roller is not transmitted, and a plurality of sheet materials are stored in the stacking storage section. The image forming apparatus according to claim 1, wherein the drive of the paper feed roller and the drive of the separation roller are transmitted when the paper is present and is carried out. 3. In the first state, the stacking and storing section has a stacking tray and the sheet material pressing means above the sheet material, and has a movable tray and a feeding means below the sheet material, The movable tray is configured to swing with respect to the stack tray around a position facing the swing center, and when the stack storage unit swings from the first position to the second position, The image forming apparatus according to claim 1, wherein the image forming apparatus swings. 4. When a plurality of originals are image-formed on both front and back surfaces of a sheet material to form one copy from two originals, the first operation is performed in a circulation sort mode in which the originals are circulated multiple times. When circulating, the number of originals is 1 while checking the number of originals.
Images are formed on every other sheet, stored in the stack storage unit at the first position, and when the second and subsequent documents are circulated, paper is alternately fed from the paper feeding device and the stack storage unit that is swung to the second position. The sheet material for which image formation has been completed is discharged out of the machine, and the sheet material for which only one surface has been imaged is stored by swinging the stack storage section to the first position between the sheets of the sheet material sent out from the stack storage section. 2. The process according to claim 1, wherein the final image forming process forms an image on every other unformed original by feeding paper only from the stacking storage unit which is swung to the second position. The image forming apparatus described. 5. The plurality of conveying roller pairs of the second conveying section are configured to be independently controllable by a plurality of driving means,
The first plurality of sheet materials in the first image forming step are conveyed in advance to the second conveying section, stopped and waited, and the succeeding sheet material is
The second side image forming is performed in the order of the sheet material in the standby state and the sheet material in the stacking / storing section at the same time when the originals are completely stored in the stacking / storing section. The image forming apparatus according to item 1. 6. When image formation is performed a plurality of times on the same surface of the sheet material, the sheet material is stored in the stack storage section after the odd-numbered image forming process is completed, and the plurality of sheet materials positioned at the rearmost end are 2. The image forming method according to claim 1, wherein the sheet material is conveyed from the first conveying portion to the second conveying portion, and subsequently, the sheet material stacked in the stacking and storing portion is sent out to form an even number of times of image formation. apparatus. 7. An image forming apparatus that circulates to form a plurality of images on the front and back surfaces of a sheet material, or on the same surface, and a first transport section extending from a branch section of a sheet discharge section, and an entry / exit position of the sheet material. And a plurality of such sheet materials can be stored in the reverse storage unit arranged substantially vertically, and a forward / reverse rotatable sheet feeding roller and a separation roller for performing frictional separation at the entrance of the reverse storage unit. A sheet feeding device; a plurality of pressing means inside the reversal storage unit that are capable of retracting and pushing the stacked sheets in one direction; and a stack of sheet materials that are located on the opposite side of the pressing means. A feeding unit that feeds the sheets one by one to the roller pair, a second feeding unit capable of feeding the sheet material fed from the reversal storage unit or the first feeding unit to the image forming unit, the first feeding unit and the first feeding unit. Confluence part of the second transport unit and the reversal storage unit And a switching means in the conveying direction, between the means pushing the preceding stacking sheet material and said inside said inversion storing unit, the image forming apparatus is characterized in that a configuration to repeatedly insert a subsequent sheet material. 8. The plurality of pressing means are arranged with independent driving means in the sheet material conveying direction,
The sheet material protrudes into the storage surface during storage standby, retracts from the storage surface immediately before the tip of the sheet material reaches each pressing means, and waits in the retracted state when sending out the sheet material. The image forming apparatus according to item 7.