JP2849485B2 - Paper reversing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet reversing device provided in a copying machine, a printer, a facsimile, or the like, for reversing the conveying direction of a conveyed sheet.

[0002]

2. Description of the Related Art Conventionally, as a sheet reversing device for reversing the conveying direction of a sheet-shaped sheet to be conveyed, for example, FIG.
There is something like that shown in This paper reversing device is provided with a pair of transport rollers 2 and 3 for transporting the paper P downward in a vertical transport path 1 for transporting the paper P in the vertical direction, and a return roller unit 5 that can rotate in the reverse direction below the transport rollers 2 and 3. The paper P is transported downward in the vertical transport path 1 by the transport rollers 2 and 3 and the return rollers 9 and 15 of the return roller unit 5, and after the upper end of the paper has passed the branching section 4, the return roller 9 The sheet P is reversely rotated in the direction indicated by the arrow A and transported upward, and the sheet P is guided to the branch path 7 by the branch claw 6 provided in the branch section 4 and switched to the rotation position indicated by the phantom line. The sheet is discharged by the conveying force of the conveying rollers 2 and 8.

The return roller unit 5 includes a return roller 9 and two rollers 11 and 12, and a timing belt 13 is stretched between pulleys which are fixed to the respective rollers. The entire unit is swingable about a roller shaft 14, and a return roller 15 on the driven side is brought into contact with the return roller 9 so as to be able to press and rotate.

When the return roller unit 5 swings in the direction indicated by the arrow B in FIG. 22, the roller 12 comes into pressure contact with the drive roller 16 which rotates in the direction indicated by the arrow, and the timing belt 13 rotates counterclockwise. Then, the return roller 9 rotates in the direction opposite to the arrow A to convey the sheet P in the vertical conveyance path 1 downward, and when the roller 11 swings in the direction opposite to the arrow B, the roller 11 The timing belt 13 rotates clockwise in the reverse direction, and the return roller 9 rotates in the direction indicated by arrow A to contact the auxiliary roller 17 rotating in the direction indicated by the arrow. P is transported upward.

In the paper reversing device, one of the paper conveyance guides in the vertical conveyance path is attached to a cover formed to be openable and closable with respect to the apparatus main body. In some cases, the transport path is opened, and if there is jammed paper there, the jammed paper can be easily taken out. In such a paper reversing device, a branching claw is attached to the main body of the device.

Further, as described in Japanese Patent Application Laid-Open No. 60-128162, an air nozzle is provided at a branch portion of a conveyance path, and air is blown against a sheet conveyed in the conveyance path from the air nozzle and pressed against a guide plate. As described in Japanese Unexamined Patent Application Publication No. 62-231963, a U-shaped reversing path is provided in the machine in order to use the waist of the paper in order to reduce the difference in movement for each paper size. There is also a paper reversing device.

[0007]

However, a return roller unit which can be swung by a plurality of such rollers is configured to rotate in both forward and reverse directions, thereby reversing the sheet conveying direction. In the case of the paper reversing device, the cost tends to be high due to a complicated mechanism.

In the case of a sheet reversing device in which one of the sheet conveyance guides of the vertical conveyance path is attached to an openable / closable cover, a branching claw is provided on the apparatus main body side.
If the paper in the vertical conveyance path is jammed between the paper conveyance guide on the main body side and the branch claw, there is a drawback that even if the cover is opened, the branch claw is in the way and it is difficult to remove it. Also, the paper transport guide on the cover side had to be provided with a notch to avoid interference with the long shaft supporting the branch claw. Was sometimes jammed when hit by the tip.

Further, in the case of the paper reversing device disclosed in Japanese Patent Application Laid-Open No. 60-128162, a device for outputting air and a device for controlling the output timing and the like are required, so that the configuration becomes complicated. JP-A-62-231
In U.S. Pat. No. 963, a U-shaped reversing path is provided in the machine, which tends to increase the size of the entire apparatus.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a low-cost paper reversing apparatus which has a simple mechanism and can reliably reverse the paper without causing a jam or the like. It is intended to be able to be manufactured in. It also is an object to the whole apparatus compact by easy single structure and mechanism.

[0011]

In order to achieve the above object, the present invention provides a pair of transport rollers for transporting a sheet downward in a vertical transport path for transporting a sheet in a vertical direction, and a pair of rollers below the transport roller. Is provided with a pair of return rollers that rotate in only one direction to return the paper conveyed downward by the transport rollers upward and that can rotate in only one direction, and a vertical transport path is provided between the return rollers and the transport rollers by the return rollers. the paper returned an inner upwardly to form a branched path that is branched from the vertical transport path, arranged branching claw to newly conveyance path of the paper in the vertical transport path and branch path to the branch portion, the returning roller Same as the roller shaft of the drive side roller
A paper guide roller is rotatably provided on the shaft, and the paper guide
The outer diameter of the roller is larger than the outer diameter of the roller on the drive side.
Form the paper guide rollers onto the outer surface of the paper
When the above roller shaft is rotated in contact with
It does not rotate due to friction with .

[0012]

[0013]

Similarly, a pair of transport rollers and a pair of
A return roller is provided, and the inside of the vertical transport path is returned upward.
The branch path that branches the paper to be
And a branching claw disposed at the branch portion, a sheet size input means for inputting a sheet size is provided, and a sheet conveyed in the transport path is detected upstream of the transport roller in the vertical transport path. A branching claw at a position to guide a sheet to a branch path at a different timing according to each sheet size input from the sheet size input means based on an output timing of a sheet detection signal from the sensor. It is preferable to provide a sheet reversing device by providing reversal timing control means for switching and pressing the pair of return rollers.

Further, in the paper reversing device, paper type signal output means for outputting a different signal according to the paper type of the paper is provided, and a branch claw guides the paper to the branch path according to an output signal from the means. It is more effective to provide a timing adjusting means for adjusting the reversal timing at which the pair of return rollers are brought into pressure contact with each other while switching to a position where the pair of return rollers are pressed.

[0016]

According to the paper reversing device constructed as described above, the paper is conveyed downward using its own weight in the vertical conveyance path, and the paper is fed only in one direction on the return side provided below the vertical conveyance path. The transport direction is reversed by a pair of rotating, releasable return rollers, and the transport direction is returned upward, and the transporting direction can be transported from the vertical transport path to the branch path by the branch claw whose rotational position has been changed. Therefore, the paper can be surely inverted without causing a jam by using a simple mechanism that does not swing a plurality of return rollers and does not rotate the rollers in both the forward and reverse directions. .

[0017]

A paper guide roller is rotatably provided coaxially with a roller shaft of a roller on the drive side of the return roller.
Te is larger than the outer diameter of the outer diameter of the driving roller
At the same time, the paper guide rollers
Friction with the roller shaft when the roller shaft rotates
The paper conveyed downward along the vertical conveyance path is guided by the paper guide rollers.
The paper is smoothly transported without contacting the drive roller of the return roller rotating in the direction of returning the paper upward while being separated while being separated, and is reversed and transported upward after the return roller is pressed against the roller. Is done.

[0019]

Further, a sheet size input means is provided, a sensor for detecting a sheet is provided on the upstream side of the conveying roller in the vertical conveying path, and the position of the branching pawl is switched to press the pair of return rollers against each other. If the timing control means is provided, when the paper is conveyed downward in the vertical conveyance path, based on the output timing of the paper detection signal from the sensor detecting the paper conveyance, the inversion timing control means separates the paper size input means. The branch claw is switched to a position for guiding the paper to the branch path at an optimum timing according to each paper size input from the printer, and a pair of return rollers are pressed against each other.
The timing at which the sheet is reversed and returned is shifted, so that the sheet does not interfere with the subsequent sheet and cause a jam.

If the paper reversing device is provided with a paper type signal output means and a timing adjustment means, the timing adjustment means guides the paper to the branch path through the branch claw according to the output signal from the paper type signal output means. Since the position is switched and the reversal timing for pressing the pair of return rollers is adjusted, the paper can be reversed at an optimal timing further considering the paper type such as the paper thickness.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of a sheet reversing device to which the present invention is applied , and FIG. 2 is an overall configuration diagram showing an entire copier equipped with the same sheet reversing device.

The copying machine shown in FIG. 2 is provided with a paper feed system 23 in which a plurality of paper feed trays are arranged below the apparatus, and feeds the paper P from the selected paper feed tray, and feeds the paper P to a roller or the like. Is transported to an image forming system 24 by a transport system using an optical system 25, where an image corresponding to the document D on a contact glass 26 is formed on a photoreceptor 27 by an optical system 25 to form a latent image. The image is visualized by 28 and is transferred to the sheet P by the transfer unit 29.

After the image P is transferred to one side of the sheet P, the sheet P passes through the fixing device 31 and then proceeds straight through the transport branching section 32 in accordance with the designated mode to be discharged onto the sheet discharge tray 33 or is discharged to the lower sheet. After being once fed into the reversing device 30, the transport direction is reversed, and is transported again upward, so that the double-sided tray 3
6, the paper is fed again, the image is transferred to the back side where no image is formed, and the paper advances straight through the transport branching section 32 and is discharged onto the paper discharge tray 33.

As shown in FIG. 1, the sheet reversing device 30 is provided with a pair of paper conveying guides 37, 38, and 39. And the paper P conveyed downward by the transport rollers is returned below the transport rollers 43 and 44. The paper P rotates only in the direction indicated by the arrow in FIG. A pair of return rollers 45 and 46 are provided.

A branch path between the return rollers 45 and 46 and the transport rollers 43 and 44 for branching the sheet P returned upward in the vertical transport path 41 by the return rollers 45 and 46 from the vertical transport path 41. 47 is formed by a paper transport guide 48 and a paper transport guide 39 which also serves as a part of the vertical transport path 41, and a branch portion 49 switches the transport path of the paper P between the vertical transport path 41 and the branch path 47. A claw 51 is provided, and a driven transport roller 40 that rotates in pressure contact with the transport roller 44 is provided in the branch path 47.

Further, the transport rollers 44 of the vertical transport path 41
A sensor 52 is disposed on the upstream side of the conveyance of the sheet, and the filler portion 52a rotatable in the direction of arrow C is rotated by the sheet P conveyed in the vertical conveyance path 41 in the direction of arrow C to pass the sensor. Can be detected. The branching claw 51 provided in the branching portion 49 can be rotated to a position shown by a virtual line in FIG. 1 by a branching solenoid 53, and is normally turned by a biasing force of a coil spring 54 into a solid line in FIG. At the position shown, actuate the branch solenoid 53 (ON)
When this is done, it switches to the position indicated by the imaginary line against the urging force of the coil spring 54.

In FIG. 1, the right side of the pair of return rollers 45 and 46 is a driving roller, which is always rotated in the direction indicated by an arrow by a driving motor (not shown), and the left side is a driven roller. When it comes into pressure contact with the return roller 46 on the driving side, it rotates in the direction indicated by the arrow. The driven-side return roller 45 is rotatably supported at one end of an L-shaped swing lever 55. The swing lever 55 is swingable with its center substantially supported by a pin 56, and is swingable at the other end. When the movable shaft of the solenoid 57 is connected and actuated (turned on), the swing lever 55 swings in the direction indicated by the arrow E, and the return roller 45 on the driven side is driven by the return roller 46 on the drive side. It rotates by pressing against a predetermined pressure suitable for conveyance.

In the sheet reversing device 30, when the duplex mode is selected, the sheet P on which an image is formed on one side is conveyed from the upper side to the lower side in FIG. 1, and rotates in the direction indicated by the arrow in FIG. The sheet is conveyed downward by a pair of conveying rollers 43 and 44, and the upper end (rear end) of the sheet is conveyed by conveying rollers 43 and 44.
Passes through the nip portion Np, and then falls in the vertical transport path 41 by its own weight, and enters between the return rollers 45 and 46 whose lower ends are separated.

At the timing when the upper end of the paper P reaches the vicinity of the position POa guided by the branch claw 51, the branch solenoid 53 is operated to absorb the movable shaft portion into the solenoid body, and the branch claw 51 is moved. The position shown by the solid line in FIG. 1 is switched to the position shown by the virtual line. The operation timing of the branching solenoid 53 is performed, for example, after a predetermined elapsed time from when the sensor 52 detects the upper end (rear end) of the sheet P to when the upper end approaches the position POa.

The solenoid 57 is operated at almost the same timing as the operation of the branch solenoid 53, and the driven return roller 45, which has been separated, is fed into the drive return roller 46, and the lower end is fed therebetween. The paper P is brought into pressure contact with the paper P. Then, the return roller 46 is always in FIG.
, The paper P is conveyed upward. Therefore, the sheet P is guided by the branching claw 51 at the position shown by the phantom line in FIG. And is conveyed into the branch path 47, and is conveyed to the double-sided tray 36 described with reference to FIG.

As described above, since the sheet reversing device 30 uses the substantially vertical vertical conveyance path 41 without making the conveyance path for reversing the conveyance direction of the paper horizontal, the conveyance path is horizontally In the case where the sheet is disposed in a shape, after the trailing edge of the sheet has passed through the nip portion corresponding to the nip portion Np of the transport rollers 43 and 44 in FIG. 1, the sheet advances only by inertial force. Takes a longer time than necessary to reach the position guided by the branch claw (corresponding to POa in FIG. 1), and the time is not constant, so that the switching timing of the branch claw is difficult. In some cases, a jam occurs at the branch claw portion. However, according to the sheet reversing device 30 , such a problem does not occur.

That is, when the paper P conveyed downward in the vertical conveyance path 41 in FIG. 1 passes through the nip portion Np of the conveyance rollers 43 and 44, the paper P stops receiving the conveyance force from those rollers. Of the return rollers 45 and 46 which are separated from each other by their own weight. By utilizing the own weight of the paper itself, the number of paper transport rollers on the transport path can be minimized, so that the apparatus has a simple configuration. Also, the return roller 45,
Since 46 is rotated only in one direction, the control is simplified and the mechanism is simplified accordingly.

FIG. 3 is a schematic diagram showing an example of a sheet reversing device provided with a sheet guide member for guiding a sheet to a return roller on the driving side.
FIG . In the sheet reversing device 60, the sheet carrying-in and discharging paths are arranged in reverse to the sheet reversing device 30 in FIG. 1 described above, and the vertical conveyance path 61 is arranged to be slightly inclined with respect to the vertical direction. A branch path 69 for carrying out the sheet P after reversing the transport direction is arranged substantially vertically. The positions and parts of the components such as the solenoid for branching 53 for switching the position of the branch claw 51, the swinging lever 55 for moving the coil spring 54 and the return roller 45 on the driven side, the coil spring 58, and the solenoid 57 are also described. Although the shape is slightly different from that of FIG. 1, corresponding parts are denoted by the same reference numerals.

In the sheet reversing device 60, the roller 46 on the driving side of the pair of return rollers 45, 46 is a roller in which a plurality of rollers 46a are arranged at intervals on a roller shaft 63 as shown in FIG. As shown in FIG. 3, the guide surface 64a for guiding the sheet P to two places (which can be appropriately increased or decreased as necessary) between the plurality of rollers 46a is provided on the sheet transport side (the same as the sheet contact portion 46b of each roller 46a). (Left in the figure) are provided in the form of sheet guide members 64, 64, respectively.

The drive-side return roller 46 has a drive pulley 65 (which may be a sprocket) fixed to a roller shaft 63 integral with the return roller 46, and a timing belt 68 wound around the pulley 65 is integrated with the transport roller 44. Each of the rollers is attached to a rotating pulley 66 and a pulley 67 rotatably provided at a position distant from the pulley 66, and the timing belt 68 is rotated in the direction indicated by the arrow J so that each roller is rotated by the arrow in FIG. Each is rotated in the direction shown.

When the sheet P is transported downward from the vertical transport path 61 in FIG. 3, it is transported downward by a pair of transport rollers 43 and 44 rotating in the direction indicated by the arrow in FIG. When the upper end (rear end) of the sheet P passes through the nip portion Np of the conveying rollers 43 and 44, the sheet P falls in the vertical conveying path 61 due to its own weight, and the branch claw 51, the sheet conveying guide 37, and the sheet guiding member. 64, and enters between the return rollers 45 and 46 whose lower ends are separated.

At this time, the upper end (rear end) of the sheet P passes through a sensor 52 (shown in a simplified manner) disposed upstream of the conveying roller 43 and then the rear end of the sheet P conveys. The branching solenoid 53 is operated (turned on) to switch the branching claw 51 to the position shown by the phantom line in FIG. The return roller 45 on the drive side is pressed against the return roller 46 on the drive side, the sheet P is inverted and raised by the rotational conveyance force in the direction indicated by the arrow, and the inside of the branch path 69 is indicated by the conveyance rollers 44 and 40 in the direction indicated by the arrow. Convey in the F direction.

Then, the leading end of the sheet P is transported by the transport roller 4
When the discharge sensor 62 disposed on the downstream side of the conveyance of the sensor 0 detects that the branching solenoid 53 and the solenoid 57 are both turned off, the biasing force of the coil spring 54 is moved to the position shown by the solid line in FIG. Back with
The return roller 45 is separated from the 46 by the urging force of the coil spring 58.

As shown in FIG. 5, when the return roller 46 is always rotating in the direction of the arrow for returning the paper P when the paper P descends in the vertical transport path 61 as shown in FIG. As shown in FIG. 6, the tip Pa of the paper P and the antinode Pb of the paper P contact the return roller 46 on the drive side, and a force acts in a direction opposite to the downward movement of the paper P. Paper P
Could not be transported smoothly and could become jammed.

However, according to the sheet reversing device , as shown in FIG.
a, the paper guide member 64 provided between the guide surfaces 64a
Is provided so as to protrude to the left side of the paper transport side in FIG. 3 from the paper contact portion 46b of each roller 46a as shown in FIG. 3, so that the transport rollers 43 and 44 move downward in the vertical transport path 61. The conveyed sheet P advances between the return rollers 45 and 46 without contacting each roller 46a of the return roller 46, and when the solenoid 57 is operated, the sheet P
Is pressed against the roller 46a of the drive-side return roller 46 in a state of being bent against the stiffness of the paper by the return roller 45 as shown in FIG. Transported to

[0042] Figures 8 to 10 shows an embodiment of a sheet inverting <br/> equipment according to the invention, parts corresponding to FIGS. 3 and 4 are denoted by the same reference numerals.

As shown in FIGS. 8 and 9, the sheet reversing device 70 is rotatably disposed coaxially with the roller shaft 63 of the drive-side return roller 46, and has an outer diameter of the drive-side return roller 46. Is larger than the outer diameter of each roller 46a, and the friction coefficient of the contact surface (outer peripheral surface) 71a with the paper P is
a paper guide roller 7 smaller than the friction coefficient of the outer peripheral surface
3 is different from the sheet reversing device 60 of FIG. 3 only in that the sheet guide member 64 of FIG. 3 is eliminated and the sheet transport guide 73 is provided between the return roller 46 and the branch claw 51.

The paper guide roller 71 is
During the rotation of the shaft 63, it does not rotate due to friction with the shaft 63. That is, for example, the paper guide rollers 71
The moment of inertia due to the frictional force between the outer surface of the sheet P and the paper P is made larger than the moment of inertia due to the frictional force between the inner surface of the paper guide roller 71 and the roller shaft 63, or the inner surface of the paper guide roller 71 and the roller shaft 63 The friction coefficient is brought close to 0 (zero) by interposing a ball bearing between the two.

The sheet reversing device 70 also allows the sheet P
When the paper P is naturally conveyed downward in the vertical conveyance path 61 by its own weight, the paper P is returned to the return roller 4 as shown in FIG.
Although it may come into contact with the paper guide roller 71 larger than the outer diameter of the return roller 6, the return rollers 45 and 46 which are in a separated state without contacting the return roller 46 rotating in the direction indicated by the arrow in FIG. In this case, no force is applied to the sheet in the direction opposite to the advancing direction, and the sheet is smoothly conveyed. When the sheet P is turned over and transported toward the branch path 69, the return roller 45 is moved through the return roller 4 via the sheet P as shown in FIG.
6 and transport it.

FIGS. 11 to 13 are schematic views showing an embodiment of a sheet reversing device in which a branching pawl is provided on a cover which can be opened. The sheet reversing device 80 includes an apparatus main body fixing unit 8 that also serves as one sheet conveyance guide 82 that forms a vertical conveyance path 81.
As shown in FIG. 12, a cover 84 that can be opened and closed about a shaft 93 is provided for the device 3, and a branch claw 85 is attached to the cover 84.

The branch claw 85 is fixed to a shaft 86 rotatably supported by the cover 84, as shown in FIG. 13, and an engaging projection 87 is fixed to one end of the shaft 86, and As shown in FIG. 7, the tip of the engaging projection 87 is engaged with a notch formed at one end of a swing lever 88 whose center is swingably supported by a pin 89. The movable shaft of the branching solenoid 53 is connected to the other end of the swinging lever 88, and the coil spring 54 is attached to the swinging lever 88, whereby the swinging lever 88 is moved in the suction direction of the branching solenoid 53. Is always urged in the direction of opposition.

In the sheet reversing device 80, as shown in FIG. 11, the sheet P conveyed downward in the vertical conveying path 81 with the cover 84 closed is further conveyed downward by the pair of conveying rollers 43 and 44. When the rear end (upper end) separates from the roller and reaches the position of the branch claw 85, the branching solenoid 53 is activated (turned on), and the swing lever 88 swings counterclockwise in FIG. Then, the branch claw 85 switches from the position indicated by the solid line to the position indicated by the virtual line. Then, the return rollers 45 and 46, which have been pressed and rotated in the directions indicated by arrows in FIG. 11 until now, rotate in the reverse direction, and the paper P is guided by the branch claws 85 and conveyed to the branch path 47.

The paper P conveyed downward in the vertical conveyance path 81 shown in FIG. 11 may be jammed between the paper conveyance guide 82 of the apparatus main body fixing portion 83 and the branch claw 85. In such a case, if the branch claw 85 is located on the apparatus main body fixing portion 83 side as shown in FIG. 14, it is troublesome to remove the jammed paper Pj because the branch claw 85 is in the way. However, in this embodiment, since the branch claw 85 is provided on the cover 84 as shown in FIG. 12, if the cover 84 is opened to the apparatus main body fixing portion 83, the jammed paper can be easily removed. it can.

In the case of the sheet reversing device shown in FIG.
Since the branching claw 85 is attached to the apparatus main body fixing portion 83 side, a cutout 84a is provided on the paper transport guide on the cover 84 side in order to avoid interference with the shaft 86 fixing the branching claw 85. However, according to this embodiment, such a notch is formed in the cover 84 as shown in FIG.
Since the sheet P is not formed on the sheet conveyance guide 84b, the sheet P can be smoothly conveyed without causing a jam.

FIGS. 15 to 21 show an embodiment of a paper reversing device in which the timing of reversing the paper is made different for each paper size, and portions corresponding to FIG. 3 are denoted by the same reference numerals.

The paper reversing device 90 is provided with paper size input means 94 such as a key for inputting a paper size, as shown in FIG. A sensor 52 for detecting the sheet P conveyed in the direction indicated by the arrow G is provided, and the sensor 52 according to each sheet size input from the sheet size input means 94 with reference to the output timing of the sheet detection signal from the sensor 52. At a different timing, the branch solenoid 53 is driven to switch the branch claw 51 to the position shown by the imaginary line for guiding the sheet P to the branch path 69, and at the same time, a control device 100 for pressing the return roller 45 against the 46 is provided. ing.

In addition to the paper size, a paper type signal output means 95 for outputting a different signal according to the paper type such as the paper thickness is provided by a selection key or the like which can be operated from the outside. A drive motor 10 for adjusting the reversal timing for pressing the pair of return rollers 45 and 46 against each other in accordance with an output signal from the unit, and driving the return roller 46 in accordance with a signal from a sheet discharge sensor 107 described later.
8 is also controlled. That is, in this embodiment, the control device 100 functions as an inversion timing control unit and a timing adjustment unit.

The control device 100 includes a central processing unit (CPU) having various judgment and processing functions, and an RO storing various processing programs and data including various programs.
M and RAM which is a data memory for storing processing data
And an input / output circuit (I / O), and also has a timer function.

The sheet reversing device 90 is provided with a fixing device (FIG. 2).
A switching claw 97 is provided at a branch portion between the discharge conveyance path 96 and the vertical conveyance path 61 which are used when the paper P exiting the fixing device 31 is directly discharged to the outside of the apparatus. A fixing sensor 92 is provided on the path, and when the fixing sensor 92 detects the leading edge of the paper P, the switching claw 97 is switched to the position indicated by the solid line and the virtual line in FIG. 15 according to the designated mode. I have to.

The switching claw 97 is driven by a solenoid (not shown), and the branch claw 51 is driven by a branch solenoid 53 having a specific shape shown in FIGS.
The movable solenoid 53 a of the branching solenoid 53 has a lever 98.
Is connected to the arm 99 via the. Its arm 99
Is mounted at a substantially central portion thereof on a lever 101 for a branch claw, which is fixed integrally with the branch claw 51, in a swingable manner, and at the right end thereof, the lower end is fixed to the right end of the roller support lever 104. The lower surface portion of the arm 99 is always in contact with the upper surface on the right end side of the roller support lever 104 whose center portion is swingably supported by the pin 103.

The roller support lever 104 has a return roller 45 rotatably mounted on the L-shaped lower end thereof, and a return spring 105 mounted on the right end thereof, which is constantly urged to rotate clockwise. In this way, the swing angle is restricted to a predetermined angle by a stopper (not shown) so that the lower portion of the arm 99 always contacts the upper surface on the right end side of the roller support lever 104.

Accordingly, the branching solenoid 53 is
In the off state as shown in FIG. 6, the movable shaft 53a and the arm 99 are moving downward by their own weight and the urging force of the return spring 105, and the roller support lever 104 is rotated clockwise to rotate the return roller 45. In a state separated from the drive-side return roller 46, the branch pawl 51 is pivoted about the fulcrum 51a to the position shown in FIG. 16 by the branch pawl lever 101 which is also pivoted clockwise. .

When the branching solenoid 53 is turned on, the arm 99 is pulled up as shown in FIG. 17, and the branching pawl 51 is rotated counterclockwise from the position shown by the imaginary line to support the roller. The lever 104 rotates against the urging force of the return spring 105, and the return roller 45 comes into pressure contact with 46.

In the sheet reversing device 90, the switching claw 97 shown in FIG. 15 is rotated to a position shown by a solid line in FIG. It turns to the position shown by the imaginary line in FIG.
In the non-reversing mode, the sheet P in the discharge conveyance path 96 is
Is discharged to the outside of the apparatus by the discharge roller pair 106, and the discharged paper is detected by a discharge sensor 107 disposed near the upstream side of the discharge roller pair 106 in the conveyance direction. Is being checked.

In the reverse mode, the sheet P guided in the direction of arrow G by the switching claw 97 moved to the position shown by the solid line in FIG.
At this time, when the sensor 52 detects the leading end of the sheet P, the branch solenoid 53 is turned off as shown in FIG. 18 and the branch claw 51 is set to the position shown by the solid line in FIG. Therefore, the paper P is further transferred to the paper transport guide 3.
The return roller 45 is transported downward in the vertical transport path 61 while being guided by the rollers 7 and 73, and the lower side thereof is separated.
And between 46 and 46.

Then, the rear end (upper end) of the paper P is
2, the control device 100 starts counting of the timer in the CPU at the same time. When the count value reaches a count value (time) T shown in FIG. By operating (turning on) 53, the branch claw 51 is switched to the position indicated by the imaginary line in FIG. Note that the count value that differs for each sheet size for turning on the branch solenoid 53 is such that the trailing end of the sheet P is the transport roller 43, 44 for all sheet sizes.
Is set in advance at a timing below the nip.

As described above, since the return roller 45 is pressed against the link 46 in conjunction with the operation of the branch solenoid 53, both of them rotate in the direction indicated by the arrow in FIG. It is transported upward. Thereafter, the sheet is discharged out of the apparatus by the discharge roller pair 106 by the same operation as the non-reversal mode.

When the next sheet P is detected again by the sensor 52, the branching solenoid 53 is turned off again. When the final discharge of the sheet P is detected by the sheet discharge sensor 107 as shown in FIG. 18, both the branch solenoid 53 and the drive motor 108 are turned off. The timing at which the branch solenoid 53 is turned on after the sensor 52 no longer detects the sheet P is actually determined by the delay time (80 to 120 ms) associated with the operation of the branch solenoid. Operation (4 of return roller 45)
6 may be operated at a timing including the count value T + delay time in FIG.

When the rear end (upper end) of the paper P conveyed downward along the vertical conveyance path 61 in FIG. 15 passes through the conveyance rollers 43 and 44, the initial speed of the paper P is conveyed by the conveyance rollers 43 and 44 from that point. Paper transport guide 3 by speed
A free fall state follows 7, 73. The drop speed at that time is greatly affected by the difference in frictional resistance between the paper P and the guide plate depending on the width of the paper P and the length in the transport direction.

That is, when the count value T shown in FIG. 18 counted after the passage of the sheet P is detected by the sensor 52 reaches a predetermined value (time), the position of the trailing end (upper end) of the sheet is the sheet size. Each position is different. This is because the inversion time Ton (the time from when the sensor 52 detects the trailing edge of the sheet P to when the sheet ejection sensor 107 detects the leading edge of the sheet P) shown in FIGS. It is clear from the experimental results that differ depending on the length in the direction.

Therefore, when the count value T is short,
Before the trailing edge of the paper P is located sufficiently below,
15 is switched to the position indicated by the imaginary line in FIG. 15, so that when the paper P is turned upward, the leading end of the paper P does not enter the nip of the transport rollers 40 and 44, and thus the ears are easily broken.
Further, when the count value T is long, the free fall time becomes longer, so that the variation of the falling position of the paper P increases, and the variation of the interval between the subsequently transported paper increases.

When the count value T reaches a length exceeding a predetermined time, the sheet P is transported by the transport rollers 40 and 4.
Before entering the nip of No. 4, the subsequent sheet reaches the sensor 52 and the branching solenoid 53 is turned off, so that the sheet P is jammed. However, in this embodiment, the count value T, which is the timing for switching the branch claws 51 for each paper size (paper width, length in the transport direction).
Since (time) is made different for each paper size as shown in FIG. 21 to make the timing optimal for each paper size, such inconvenience does not occur.

This timing control is performed, for example, by storing the paper size in the memory of the control device 100 simultaneously with the start of the copying operation, searching the data table of FIG. 21 based on the stored paper size, and reading out the corresponding data. Do.

In this embodiment, the paper type signal output means 95 provided in the operation unit of an image forming apparatus such as a copying machine is provided.
The count value T is further adjusted by the paper thickness input from (FIG. 15) (or may be set by a paper type due to a difference in frictional resistance or the like), so that the value is corrected. The sheet can be surely reversed at an appropriate reversal timing. That is, if the paper thickness mode input from the operation unit is the thick paper mode, the count value (time) T is set to +
10 ms, and the count value T is -10 in the thin paper mode.
Adjust to ms timing.

In this embodiment, the input of the paper thickness information to the control device 100 is externally performed by the paper type signal output means 95 using a key or the like. However, this means is provided on the transport path. The paper thickness may be automatically detected by a sensor for detecting the paper thickness.

[0072]

As described above, according to the present invention, the following effects can be obtained. According to the invention of claim 1,
The paper is conveyed downward in the vertical conveyance path using its own weight and sent between the return rollers that are separated from each other. Since it is not rotated or reversely rotated, the mechanism is simple, and the paper can be surely inverted without causing a jam or the like at a low cost.

[0073] The sheet to lower the vertical conveyance path because it does not contact with the paper guide roller to roller return is rotating in a direction to return the Re its <br/>, in the transport direction from roller return at the time of descent Since the sheet is not subjected to the reverse frictional force, the sheet is smoothly conveyed without causing a jam or the like, and after the return roller is pressed, the sheet is surely inverted and discharged.

[0074]

According to the second aspect of the present invention, the position of the branching pawl is switched at an optimum reversal timing adjusted for each sheet size and according to the third aspect of the present invention in addition to the type of paper. Since the paper is reversely transported by pressing the return roller, it is possible to absorb variations in the transport speed in the vertical transport path for different paper for each paper size and paper type, thereby reducing the occurrence of paper breaks and jams. Can be. In addition, since variations in operation are absorbed by delicately controlling the reversal timing, the sheet can be reversed and conveyed by a simple mechanism without requiring a complicated and large-sized apparatus as in the related art.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a sheet reversing device to which the present invention is applied .

FIG. 2 is an overall configuration diagram showing the entire copying machine equipped with the sheet reversing device of FIG. 1;

FIG. 3 is a schematic configuration diagram illustrating an example of a sheet reversing device in which a sheet guide member is provided on a drive-side return roller.

FIG. 4 is a plan view showing a positional relationship between a return roller and a sheet guide member of the sheet reversing device of FIG. 3;

FIG. 5 is an explanatory diagram for explaining a state in which the leading edge of the sheet comes into contact with a return roller and causes a problem when the sheet reversing device has no sheet guide member.

FIG. 6 is an explanatory diagram for explaining a situation in which an antinode of a sheet comes into contact with a return roller and causes inconvenience when the sheet reversing device has no sheet guide member.

FIG. 7 is a plan view showing a state where a pair of return rollers of the sheet reversing device of FIG.

FIG. 8 is a schematic configuration diagram showing an embodiment of a sheet reversing device according to the present invention .

9 is a plan view illustrating a positional relationship between a return roller and a sheet guide roller of the sheet reversing device in FIG. 8;

FIG. 10 is a plan view showing a state in which a pair of return rollers of FIG. 9 are pressed against each other across a sheet.

FIG. 11 is a schematic configuration diagram illustrating an embodiment of a sheet reversing device in which a branch claw is provided on a cover that can be opened.

12 is a schematic diagram showing a state in which a cover of the sheet reversing device of FIG. 11 is opened.

FIG. 13 is a plan view showing a part of the sheet reversing device of FIG. 11 in section;

FIG. 14 is an explanatory diagram for describing inconvenience when the branch claw is provided on the device body fixing portion side.

FIG. 15 is a schematic configuration diagram showing an embodiment of a sheet reversing device configured to invert at a different timing for each sheet size together with a control system.

FIG. 16 is a schematic diagram showing a state in which a pair of return rollers of the sheet reversing device of FIG. 15 are in a separated state.

FIG. 17 is a schematic view showing a state in which a pair of return rollers of FIG. 16 are in a pressure contact state.

18 is a timing chart showing a timing chart of the sheet reversing device of FIG.

FIG. 19 is a diagram illustrating a relationship between a sheet width of a sheet and an inversion time.

FIG. 20 is a diagram illustrating the relationship between the length of a sheet in the transport direction and the reversal time.

FIG. 21 is a diagram illustrating an example of a count value T that differs for each paper size.

FIG. 22 is a schematic view showing an example of a conventional sheet reversing device.

[Explanation of symbols]

30, 60, 70, 80, 90 Paper reversing device 37, 48, 73, 82 Paper transport guides 41, 6
1 vertical transport path 40, 43, 44 transport roller 45, 46
Return rollers 47, 69 Branch path 49 Branch section 51, 85 Branch claw 52 Sensor 53 Branch solenoid 57 Solenoid 62, 107 Discharge sensor 63 Roller shaft 64 Paper guide member 64a Guide surface 71 Paper guide roller 83 Device body fixing portion 84 Cover 94 paper size input means 95 paper type signal output means 100 controller P paper

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshikazu Inoue 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Yoshiji Ishigaki 1-3-6 Nakamagome, Ota-ku, Tokyo (56) References JP-A-2-110066 (JP, A) JP-A-60-97161 (JP, A) JP-A-63-172149 (JP, A) JP-A-2-243460 (JP, A) Japanese Utility Model 63-173155 (JP, U) Japanese Utility Model 63-136653 (JP, U) Japanese Utility Model 1-126363 (JP, U) (58) Field surveyed (Int. Cl. ⁶⁾ , DB name) B65H 29/58

Claims (3)

(57) [Claims] A pair of transport rollers for transporting a sheet downward are provided in a vertical transport path for transporting a sheet in a vertical direction, and the sheet transported downward by the transport roller is returned below the transport roller. A pair of return rollers that rotate in only one direction and that can be separated from each other are provided, and a sheet that is returned upward in the vertical transport path by the return roller between the return roller and the transport roller is branched from the vertical transport path. the branch path is formed which, arranged branching claw to newly conveyance path of the paper to the bifurcation and the branch path and the vertical conveyance path, the returning roller on the driving side of the rollers of the roller shaft and coaxially
A paper guide roller is provided rotatably, and the paper guide roller is
The outer diameter is formed larger than the outer diameter of the drive-side roller.
At the same time, the paper came into contact with the paper guide roller on its outer surface.
When the roller shaft rotates in this state,
A sheet reversing device characterized in that it does not rotate . 2. A vertical conveyance path for conveying a sheet in a vertical direction.
With a pair of transport rollers that transport paper downward,
And below the transport roller by the transport roller.
That rotates in only one direction to return the paper conveyed to
A pair of return rollers that can be brought into contact with and separated from each other.
Between the transport roller and the transport roller by the return roller.
The paper returned inside the transport path is separated from the vertical transport path.
Form a branching path for branching, and feed the paper
A branch claw that switches the path between the vertical transport path and the branch path.
And paper size input means for inputting the paper size.
The transport path is located upstream of the transport rollers in the vertical transport path.
A sensor to detect the paper being conveyed inside,
Based on the output timing of the paper detection signal from the sensor
Paper size input from the paper size input means
The branch claw is used for the branch path at different timings according to
Switch to the paper guiding position and press the pair of return rollers
A sheet reversing device comprising a reversal timing control means for making contact with the sheet reversing device. 3. The sheet reversing device according to claim 2 , wherein
Paper type signal output means for outputting a different signal according to the paper type of the paper; switching the branching claw to a position for guiding the paper to the branch path according to an output signal from the means; A sheet reversing device provided with a timing adjusting means for adjusting a reversal timing for pressing the sheet.