JP3161462B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder used for an image forming apparatus or the like, and more particularly to a paper feeder capable of effectively preventing double feeding of sheets.

[0002]

2. Description of the Related Art Conventionally, in an electronic apparatus having an image forming apparatus such as a printer, a copying machine, a facsimile, etc., a paper feeder for feeding paper into the main body of the electronic apparatus is provided. In the apparatus, a friction separation device that separates and feeds the sheets one by one by a feed roller that feeds the sheets and a separation piece that separates the sheets one by one while contacting the feed rollers is provided. What is provided is known.

A sheet fed one by one by the friction separating device is conveyed in the sheet conveying direction by rotating the sheet feeding roller while receiving a constant pressing force by the sheet feeding roller and the separating piece. Then, the sheet is conveyed to the inside of the main body of the electronic device via a conveying roller provided on the downstream side in the sheet conveying direction. On the other hand, in the paper feeder having such a configuration, when paper is fed, the rear end of the paper is brought into contact with the paper feed roller due to tension (back tension) generated between the paper feed roller and the transport roller. It is known that the paper is wound around the transport roller more than a predetermined transport amount at the moment when the paper is released from being pinched with the separation piece, and these back tensions cause deterioration of the paper transport accuracy. . Therefore, by reducing the pressing force generated between the paper feed roller and the separation piece and reducing the tension (back tension) between the paper feed roller and the transport roller, the above-described deterioration of the paper transport accuracy is prevented. Was.

[0004]

However, by reducing the pressing force generated between the paper feed roller and the separation piece, a large amount of paper can easily enter between the paper feed roller and the separation piece, and There is a problem in that a plurality of sheets are conveyed into the main body of the electronic device at the same time as one sheet to be printed, that is, a so-called double feed easily occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple structure for selectively switching a pressing force generated between a sheet feeding roller and a separating piece to separate a sheet. When the paper is transported via the transport rollers, the pressing force is increased to prevent double feeding of the paper.
It is an object of the present invention to provide a sheet feeding device capable of reducing a pressing force to reduce a tension (back tension) generated between a sheet feeding roller and a conveyance roller and preventing deterioration of sheet conveyance accuracy.

[0006]

According to a first aspect of the present invention, there is provided a sheet feeding device driven by a driving unit to feed a sheet in a predetermined conveying direction, and a sheet feeding roller for the sheet feeding roller. A separation piece that abuts against the rollers to separate the sheets one by one, and a plurality of sheets that are held diagonally with the upstream side in the transport direction as the upward direction and the downstream side in the transport direction as the downward direction, and separated from the paper feed roller. A sheet support portion movably disposed between one position and a second position approaching the paper feed roller, and a first biased state for biasing the separation piece toward the paper feed roller by the first biasing force; An urging member capable of switching between a second urging state in which the separation piece is urged toward the paper feed roller by a second urging force larger than the first urging force, and a urging force of the urging member. A separating piece separating member for separating the separating piece from the sheet feeding roller by using the driving means. Being driven, and a lever return a pair of paper rotatable in the vicinity of the separation protrusions, the use <br/> paper each time to separate one sheet, first, the sheet supporting portion from the second position Move the paper support to the paper feed roller
In conjunction with the Rukoto is al spaced, said with the biasing force from the second biasing state Ru weaken the urging force against the separation pad is switched to the biasing member to the first urging state to separation piece, return the paper The lever is located at the downstream side in the transport direction, and then, in conjunction with the rotation of the sheet return lever to the upstream side in the transport direction by the driving force from the driving unit, the lever is biased by the first bias state. the separation pad separates the separation protrusions that is
Separation protrusions temporarily moved away from the paper feed roller through a member
Is released, and the paper on the paper support portion is pushed back to the upstream side in the transport direction by further rotating the paper return lever.

In this configuration, the separation piece is urged toward the sheet feeding roller by the urging member so as to be switchable between a first urging state and a second urging state. In the paper push-back operation performed in step (1), first, the biasing state on the separation piece is set to the first bias state, and the biasing force on the separation piece is
It is assumed that the paper return lever is located at the downstream side in the transport direction in a weakened state. This operation is performed in conjunction with moving the paper support unit from the second position to the first position,
By moving the paper support to the first position away from the paper feed roller, the paper holding state between the paper feed roller and the paper support is released, and after moving the paper support, the first biased state The separation piece is urged toward the paper feed roller. In the first biased state, the separation piece is biased toward the paper feed roller with a weaker biasing force than in the second biased state, but a plurality of sheets held diagonally are separated by their weight. Depressing the piece and entering between the separation piece and the paper feed roller is reliably prevented.

Subsequently, when the paper return lever is rotated by the driving force of the driving means, the separation piece urged by the first biasing state via the separation piece separating member is supplied in conjunction with this rotation. Temporarily separate from the paper roller and attach
Release the momentum. In this case, a certain amount of force is required to separate the separation piece urged by the first urging state from the sheet feeding roller, but the sheet return rotating by the driving force from the driving unit is required. By linking with the rotation of the lever,
The separation pieces can be easily separated.

When the sheet return lever is further rotated, the sheet sandwiched between the separation piece and the sheet feed roller is pushed back by the sheet return lever to the upstream side in the transport direction. At this time, since the paper return lever is rotated by receiving the driving force of the driving means, the paper held diagonally can be pushed back against the gravity, and the paper can be satisfactorily applied without burdening the paper. The paper can be pushed back to the upstream side in the transport direction. Further, by removing the sheet between the separation piece and the sheet feeding roller, it is possible to satisfactorily prevent double feeding of the sheet without depositing the sheet between the separation piece and the sheet feeding roller. Further, it is not necessary to increase the pressing force between the separation piece and the paper feed roller so that the paper is not accumulated between the separation piece and the paper feed roller, and the back tension can be reduced.

Further, in the paper feeding apparatus according to claim 2, the urging member is capable of constantly urging the separation piece toward the paper feed roller with a predetermined urging force. And a second urging member provided separately from the first urging member. Switching from the second urging state to the first urging state is performed when the paper support unit is in the first position and the second urging state. The second urging member is switched between a position capable of cooperating with the first urging member and a position incapable of cooperating with the first urging member in conjunction with moving between the positions.

In this configuration, the switching between the first biased state and the second biased state is realized by the cooperation of the two biasing members. In addition, since this switching is linked to the movement of the paper support, there is no need to provide a dedicated configuration for the switching.

Further, in the paper feeder according to the third aspect, the separating piece separating member may include a protrusion formed on the separating piece;
An engagement member disposed on the paper return lever and configured to separate the separation piece from the paper feed roller via the protruding portion based on rotation of the paper return lever on the upstream side in the transport direction. It is characterized by the following.

[0013] In this configuration, with the rotation of the paper return lever, an engagement member disposed on the paper return lever,
When the protrusion formed on the separation piece is engaged, the separation piece and the sheet feeding roller are separated from each other. Therefore, the sheet can be reliably released from being pinched by the separation piece and the sheet feeding roller, and the sheet can be pushed back to the upstream side in the transport direction.

According to a fourth aspect of the present invention, in the paper feeding apparatus, the engaging member comprises an engaging lever rotatably attached to the sheet returning lever, and the engaging lever is configured to be transported by the sheet returning lever. When rotating in the direction upstream, the separation piece is temporarily separated from the paper feed roller by pressing the upper surface of the protruding portion, and when the sheet return lever rotates in the transport direction downstream, And returning to the original position while being guided along the lower surface of the protrusion released from the pressed state.

In this configuration, when the paper return lever rotates upstream in the transport direction and pushes back the paper, the engagement lever presses the upper surface of the protruding portion and presses the paper. Acts to separate the rollers from the rollers, and when the paper return lever returns to the downstream side in the transport direction, that is, to the initial position,
Since the guide is guided along the lower surface so as to avoid contact with the protrusion, it is engaged with the protrusion only when the paper is pushed back, so that the separating piece and the paper feed roller can be temporarily separated from each other reliably. It becomes possible.

According to a fifth aspect of the present invention, the engagement lever is always urged in one direction by an urging means, and when the engagement lever is guided along the lower surface of the projection, By retreating in the other direction against the urging force of the urging means, it passes through the lower surface of the protruding portion.

In this configuration, in a state where the sheet is urged in one direction by the urging means, it comes into contact with the upper surface of the protruding portion and is pressed down, and the sheet returning lever which has completed the sheet returning operation returns to the original position. In this case, since it is not necessary to press the protruding portion, the engagement lever moves against the urging force of the urging means,
The contact with the protrusion is easily avoided. With a simple configuration using this urging means, it is possible to realize the pressing and avoiding of the protruding portion by the engagement lever, and the switching of the separation and the urging between the separation piece and the paper feed roller.

According to a sixth aspect of the present invention, in the paper feeding apparatus, the series of operations of pushing back the sheet by the sheet return lever includes an initial stage of holding the sheet return lever at a position most rotated downstream in the transport direction. When the second shaft starts rotating in one direction and the sheet return lever rotates upstream in the transport direction, the engaging lever presses the upper surface of the protruding portion to feed the separation piece. A second stage in which the paper is temporarily separated from the rollers and the paper is returned to the upstream side in the transport direction by the rotation of the paper return lever, and the paper return lever is rotated to the most upstream side in the transport direction, and the protrusion of the engagement lever A third step of returning the separation piece to the paper feed roller side by releasing the pressure on the second shaft, and the second shaft starts rotating in the other direction,
A fourth step in which when the paper return lever is rotated downstream in the transport direction and the engagement lever comes into contact with the protrusion, the engagement lever retracts downward and passes while being guided along the lower surface of the protrusion; And the following.

In this configuration, the operations of the first to fourth steps are performed simply by rotating the second shaft in one direction and in the other direction, and the mechanism is a simple mechanism. Thus, it is possible to satisfactorily push the paper sandwiched between the separation piece and the paper feed roller back upstream in the transport direction without imposing a load on the paper.

According to a seventh aspect of the present invention, in the sheet feeding device, the end of the sheet return lever is brought into contact with the leading end of the sheet substantially perpendicularly when the sheet is pushed back, and the sheet is continuously pushed back. The surface is formed.

In this configuration, at the end of the sheet return lever, a contact surface is formed which comes into contact with the leading end of the sheet at a substantially right angle when the sheet is pushed back to the upstream side in the transport direction. Therefore, when the paper is pushed back to the upstream side in the transport direction, the leading end of the paper always comes into contact with the contact surface at a substantially right angle, so that the paper can be pushed back well without bending or deforming the paper. .

In the paper feeder according to the present invention, a paper cassette for storing the papers in a stacked state and a paper cassette provided inside the paper cassette within a rotation range of the paper return lever, The present invention is characterized in that a regulating pad for regulating the rotation range of the paper return lever is provided.

In this configuration, the rotation range of the paper return lever is regulated by the regulation pad inside the paper cassette. For this reason, the paper return lever does not directly contact the paper cassette but abuts via the regulating pad, so that the paper return lever does not come into contact with the paper cassette to generate a collision sound.

According to a ninth aspect of the present invention, in the paper feeding device, the series of operations of pushing back the paper by the paper return lever includes operating the first shaft to rotate the paper feed roller, thereby causing the paper feed roller to rotate. This is performed before the separation of the sheets stacked on the sheet is started.

According to this configuration, before the paper feeding operation is performed by the paper feed roller and the separating piece, the paper return lever pushes the paper back to the upstream side in the transport direction, that is, the so-called ordering operation is performed. At this point, the sheets in the sheet cassette are always in a ready state, and it is possible to satisfactorily separate and convey each sheet.

According to a tenth aspect of the present invention, in the paper feeder, the protruding portions are provided at both ends of the separation piece, and a paper return lever is provided correspondingly. In comparison with a case where the paper return lever is operated at a location and the separation piece is pressed at one location, the entire separation piece can be uniformly pressed and separated from the paper feed roller, and when the paper is pushed back. In comparison with the case where the paper is pushed back at a location, the paper can be pushed back evenly without tilting.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an external perspective view of a multifunction device provided with the sheet feeding device of the present invention. The multi-function device 1 has various functions such as a facsimile function, a printer function, a copy function, and a scanner function.

The multi-function device 1 includes a main body housing 1a, an upper cover 1b, a paper cassette 3, an operation panel 6, a document placement section 9, a paper discharge tray 27, a document discharge tray 60, and a handset 12. It has.

The multi-function device 1 includes a plurality of key switches 6a for inputting the above-mentioned various functions and the telephone number of a communication partner, and a liquid crystal display 6b for displaying the operation state of the multi-function device 1. The operation panel 6 is pivotally supported on the upper cover 1b so as to be openable and closable about the rear end of the operation panel 6, and similarly, the upper cover 1b is centered on the front end of the upper cover 1b with respect to the main body housing 1a. It is pivotally supported to open and close.

A paper cassette 3 capable of holding a plurality of sheets as recording media, a sheet discharge tray 27 capable of holding a plurality of sheets subjected to recording processing, and a handset 12 are placed on the main body housing 1a. A handset base 13 and the like are mounted. The upper cover 1b has a document placement section 9 on which a plurality of documents can be placed, a document guide 10 which can be slid according to the size of the document, and a document discharge tray on which a plurality of read documents can be placed. 60 etc. are mounted.

The paper cassette 3 has a paper input port 66 for inputting paper as a recording medium normally used by a user, a manual paper mounting table 65 used when using paper different from the normal time, A manual paper guide 64 slidable according to the size of the manual paper is provided.

FIG. 2 is a schematic cross-sectional side view of the multifunction device 1 when the central portion is cut along the sheet transport direction. As shown in FIG. 2, inside the multi-function device 1, a reading device 5 for reading a document on which various types of information are written line by line in the width direction and information to be recorded such as received data on a paper P
And a recording device 2 that prints the information.

The reading device 5 sequentially arranges the original placing section 9 and the original separating piece 35 from the upstream side in the original conveying direction (the direction of the arrow in the figure).
b, original feed roller 35a, original transport drive roller 36
a, original transport driven roller 36b, image reading scanner 3
4, a document pressing member 38, a document discharge drive roller 37a, a document discharge driven roller 37b, and the like.

In the reading device 5 having the above-described configuration, the original placed on the original placing portion 9 is moved by the original guide 10 while the original feeding roller 35 is controlled.
a and the document is separated one by one via the document separating piece 35b, and is conveyed into the reading device 5. The original conveyed into the reading device 5 is a pair of upper and lower original conveyance drive rollers 3.
6a and the original transport driven roller 36b,
The document is conveyed to the reading unit 42. The reading unit 42 is a CIS (Co
ntact Image Sensor)
And a document pressing member 38 pressing the document to the image reading scanner 34 when reading the document, thereby reading the image for each line while bringing the conveyed document into close contact with the image reading scanner 34. The document from which the image has been read is conveyed to the outside of the main body of the multi-function device 1 while being sandwiched between a pair of upper and lower original discharge drive rollers 37a and original discharge driven rollers 37b. It is placed on a tray 60 (see FIG. 1). The pressing surface of the document pressing member 38 is formed in white and is used as a reference color for detecting the leading edge of the document and for the white level.

The above-described original separating piece 35b, original transport driven roller 36b, original pressing member 38, and original discharge driven roller 37b are mounted on the back of the operation panel 6, and the operation panel 6 is an operation panel support shaft. The operation panel 6 is pivotally supported so as to be openable and closable in a direction in which a front end (right side in the figure) of the operation panel 6 is opened. Thus, when the document is jammed on the document transport path, by opening the operation panel 6, the jammed document can be easily removed. Similarly, the document placing section 9 and the document feed roller 35
a, original transport drive roller 36a, image reading scanner 3
4. The document discharge drive roller 37a is mounted on the upper cover 1b, and is pivotally supported on the upper cover support shaft 4 so that the rear end (left side in the figure) of the upper cover 1b can be opened and closed freely. I have. Thereby, when replacing the ink cartridge 19 used for the ink jet head described later,
When the paper P is jammed, the upper cover 1b
By opening the upper part, the above-described maintenance and the like can be easily performed.

Next, details of the recording device 2 will be described. The recording device 2 includes a paper cassette 3, a separation mechanism 31, a carriage 18, a paper leading edge detection sensor 23, a transport roller 24,
It is composed of a paper trailing edge detection sensor 28, a paper discharge drive roller 26, a paper discharge driven roller 25, and the like.

The recording apparatus 2 having the above-described configuration is configured to transfer the sheet P input from the sheet input port 66 or the sheet P mounted on the manual sheet mounting table 65 via the separation mechanism 31 described later. The sheet is separated into sheets and transported into the multi-function device 1. The paper P transported into the multi-function device 1 is
After the conveyance of the sheet P is confirmed by the sheet front end detection sensor 23, the sheet P is conveyed to the print point via the conveyance roller 24. Here, a recording head 15 of a color ink jet type is mounted on the carriage 18 in a downward direction.
Printing is performed by ejecting ink onto the paper P while reciprocating on the guide shaft 17 extending in the paper width direction (perpendicular to the paper surface) while receiving power from the timing belt 20. In order to execute color printing, the printing head 15 is equipped with four printing heads 15 for discharging each color of cyan, yellow, magenta, and black in parallel. The stored ink cartridge 19 for each color is
8 are detachably mounted. The paper P on which the recording has been performed is conveyed toward the outside of the main body of the multi-function device 1 while being sandwiched between the paper discharge drive roller 26 and the paper discharge driven roller 25 formed in a pair of upper and lower sides. After confirming the discharge of the sheet P by 28, the sheet P is placed on a sheet discharge tray 27 (see FIG. 1).

FIG. 3 is a block diagram of a control unit for executing various functions provided in the multi-function device 1. As shown in FIG. 3, the CPU 52, the ROM 51, the RAM 54, the modem 55, the NCU board 56, the handset 12, the recording device 2, the paper transport unit 57, the reading device 5, the operation panel 6, the power supply unit 58, and the like. . The control unit configured as described above is provided with a CPU 5 for executing various controls and calculations.
2. ROM 51 storing a control program for instructing various control operations, RAM 54 partially used as reception buffer memory 54a, NCU board 56 for performing communication processing with other communication devices, and other communication via NCU board 56 A recording device 2 including a modem 55 for transmitting and receiving communication data to and from the device, a handset 12 for conversing with another telephone device, a carriage 18 on which a recording head 15 is mounted, etc .; Drive motor 53 to be driven
A paper transport unit 57 having a control circuit 92 for controlling the driving of the drive motor 53; a reading device 5 having an image reading scanner 34 for reading the document line by line in the width direction;
An operation panel 6 including an operation key 6a and a liquid crystal display 6b, a power supply unit 58 for supplying power to the multifunction device 1, and the like are connected via a bus line 59.

Next, the structure of the separation mechanism 31 will be described in detail with reference to FIGS. still,
4 is a schematic plan view of the separation mechanism 31 viewed from above, FIG. 5 is a schematic side sectional view of the separation mechanism 31 viewed from the side, and FIG. Are respectively shown.

As shown in FIG. 4, the separation mechanism 31 is provided with an order from the upstream side (upward in the figure) in the sheet conveyance direction.
A paper support plate 21 capable of loading a maximum of 200 sheets of paper P, a first manual feed film 43a attached to a manual feed sheet mounting table 65 (see FIG. 5) and guiding a central portion in the width direction of the manual feed paper in the paper transport direction, The second manual feed film 43b that guides both ends in the width direction, the first manual feed film 4
A film urging wire 44 for urging the sheet 3a upward, separating claws 62 disposed at both ends in the width direction of the sheet, a separating piece 30 for pressing the sheet P against a sheet feeding roller 22 (see FIG. 5) described later,
It comprises a paper return lever 50 for pushing the paper P back to the upstream side in the paper transport direction. In addition, in the separation piece 30,
It is composed of a separation pad 29 for separating sheets P one by one through the rotation of the paper feed roller 22 and a separation piece protruding portion 49 protruding in the longitudinal direction of the separation piece 30. Also,
The sheet return lever 50 includes a separation piece pressing lever 48 that can be engaged with the separation piece protrusion 49.

Next, the structure of the separating mechanism 31 as viewed from the side will be described with reference to FIGS. In order to make the drawing easy to understand, the above-described paper return lever 50 is not shown in FIG. 5, and the supplement is performed in FIG.

As shown in FIG. 5, the paper support plate 21 is rotatably supported about a support shaft 39 by a rotation mechanism to be described later, and has a downstream end (lower in FIG. 5) in the paper transport direction. Direction), a protruding portion 21a protruding downward is provided. The separation piece 30 is rotatably supported around a separation piece support shaft 41, and is always urged toward the paper feed roller 22 via a first pressing spring 32. The pressurizing member 40 is provided on the other end side of the separation piece contact portion 67 that can urge the separation piece 30 toward the paper feed roller 22 via the second pressing spring 33. And a contact portion 40a capable of contacting the protruding portion 21a. First manual feed film 43a
Is the manual paper placed on the manual paper loading table 65,
It is formed so as to guide between the separation piece 30 and the paper feed roller 22 (hereinafter, referred to as a separation point).
The second manual feed film 43b is formed so as to guide both ends in the width direction of the manual feed paper upward. The urging force of the first pressing spring 32 is such that a plurality of sheets obliquely held by the sheet support plate 21 press the separation piece 30 by their own weight,
The urging force is set to a value that can prevent unnecessary entry into the paper feed roller 22 side. Also, the second pressing spring 3
The urging force of No. 3 is set to be larger than that of the first pressing spring 32. In this embodiment, the urging forces of the first pressing spring 32 and the second pressing spring 33 are set to 100 g and 200 g, respectively.

The paper feed roller 22 rotates in accordance with the rotation of the roller shaft A (see FIG. 6), and has a substantially fan-shaped paper feed section 22a having an arc surface in contact with the paper P; And a non-feeding portion 22b having a surface not to be fed, and when the feeding portion 22a contacts the upper surface of the paper P, the paper P is fed one by one toward the transport roller 24 (see FIG. 2). Is configured. A circular paper feed roller 63 is provided on the same axis as the paper feed roller 22.
Even at the position where 2b faces each other, the sheet P loaded on the sheet supporting plate 21 does not flow between the separation piece 30 and the non-sheet feeding portion 22b because the sheet feeding roller 63 and the separation piece 30 always contact each other. It has such a configuration. Note that the arc length of the arc surface of the paper supply unit 22a is formed to be long enough to allow the paper P to reach the conveyance roller 24 from the paper supply roller 22, and the paper supply roller 22 rotates once. ,
The sheet P is configured to be fed one sheet.

As shown in FIG. 6, the paper return lever 50
Are supported rotatably about a paper return lever support shaft 68 (second shaft) extending parallel to the opposite side to the roller shaft A (first shaft) across the separation piece 30. And the direction in which the sheet transport path is opened via the second winding spring 47 (in the figure,
Clockwise). Also, the paper return lever 5
0 rotates counterclockwise about the paper return lever support shaft 68, so that the separation piece pressing lever 48, which can engage with the separation piece protrusion 49 provided on the separation piece 30, pushes the separation piece pressing lever. It is rotatably supported by the lever support shaft 69 and is urged clockwise through the first winding spring 46. Further, when the paper return lever 50 rotates counterclockwise about the paper return lever support shaft 68, the paper return lever 50 contacts the leading end of the paper P and pushes the paper P back to the upstream side in the paper transport direction. It has a contact surface 61a and a second paper contact surface 61b. Also, the paper return lever 50
The clockwise rotation of is controlled within a predetermined range via a muffling pad 45 provided on the paper cassette 3.
Note that the separation piece protruding portions 49 are provided on both left and right ends of the separation piece 30, and correspondingly, the paper return levers 50 are also provided at two places.

Here, the rotation mechanism of the sheet support plate will be described with reference to FIGS. 12 and 14, the separation piece 30, the first pressing spring 32, the second pressing spring 33, and the pressing member 40 are omitted.

As shown in FIG. 12, the paper support plate 21
In the state where the power of the rotating mechanism is not received, the front end side (the side of the protruding portion 21a) of the paper supporting plate 21 is pressed by an urging member (not shown) provided on the back side of the paper supporting plate 21 such as a compression spring.
Is urged toward the paper feed roller 22, and is rotated counterclockwise around the support shaft 39 to a position shown by a solid line and held. Then, by receiving the power of the rotating mechanism, it rotates clockwise against the urging force of the urging member,
It is configured to retreat to the position shown by the dotted line in FIG. That is, the paper support plate 21 is formed so as to be movable by a rotation mechanism between a position indicated by a solid line (second position) and a position indicated by a dotted line (first position).

As shown in FIG. 12, the rotating mechanism is a cam 70 which rotates together with the roller shaft A similarly to the sheet feeding roller 22.
And a paper support plate pressing lever 75 provided opposite to the cam 70. The cam 70 has a cam surface 70a that substantially controls the movement timing of the paper support plate 21. Also, the paper support plate pressing lever 75
Are arranged close to the upper surface side of the paper support plate 21 and the cam 70
75a, a lever 75b that presses down the paper support plate 21, and a contact 75c that contacts the cam surface 70a.
And is configured to be rotatable about a rotation shaft 80 by receiving power from the cam 70. In addition, this rotation mechanism
In the present embodiment, in order to rotate the paper support plate 21 with high accuracy, the paper support plate 21 is provided on each of the left and right ends of the paper support plate 21, and the rotation shaft 80 is formed integrally with the main body of the paper cassette 3. Also, although not shown in FIG.
The paper support plate 21 is provided with side walls at its left and right ends, and the lever portion 75b is configured to press down the side walls.

As shown in FIG. 12, the cam surface 7 of the cam 70
0a is completely engaged with the concave portion 75a of the paper supporting plate pressing lever 75, a predetermined gap is provided between the cam surface 70a and the concave portion 75a. Not powered by for that reason,
The paper support plate 21 receives no action from the rotating mechanism at all,
The force acting on the paper support plate 21 is controlled by an urging member (not shown).
, And the leading end of the sheet supporting plate 21 is positioned on the sheet feeding roller 22 side.

When the roller shaft A rotates, the cam 7
When 0 rotates in the direction of arrow X in the figure, the cam surface 70a gradually comes off the concave portion 75a. At this time, there is no contact between the cam surface 70a and the concave portion 75a due to the gap provided between the cam surface 70a and the concave portion 75a, and the rotation of the paper support plate pressing lever 75 is prevented.

When the cam 70 further continues to rotate in the direction of the arrow X, one end of the cam surface 70a starts contacting the contact portion 75c (FIG. 13A), and follows the curved surface of the cam surface 70a. The contact portion 75c is guided to rotate the paper support plate pressing lever 75 in the direction of arrow Y in the figure (FIG. 13B). With the rotation of the paper support plate pressing lever 75, the lever portion 75b starts pressing the paper support plate 21 (FIG. 13C), and a gap is formed between the paper support plate 21 and the paper feed roller 22. start.

FIG. 14 shows the state of the paper support plate 21 when the other end of the cam surface 70a reaches the contact portion 75c of the paper support plate pressing lever 75 as shown in FIG. In this state, the gap formed between the paper support plate 21 and the paper feed roller 22 is maximized. Note that the positional relationship of the paper support plate 21 in FIG. 14 corresponds to the dotted line in FIG. Further, when the cam 70 rotates, the contact between the contact portion 75c and the cam surface 70a is released, and the cam surface 70a is guided again so as to engage with the concave portion 75a. It rotates in the direction opposite to Y and returns to the state of FIG. Thus, the pressed state of the paper support plate 21 is released. A series of operations are repeatedly performed by the rotation of the cam 70.

The reciprocating movement of the paper support plate 21 is related to the pressing member 40. That is, as described above, when the paper support plate 21 rotates clockwise, the protruding portion 21a of the paper support plate 21 also rotates and comes into contact with the contact portion 40a of the pressing member 40, The contact portion 40a is moved in a direction away from the separation piece 30 against the urging force of the second pressing spring 33. Conversely, when the paper support plate 21 rotates counterclockwise, the protruding portion 21a of the paper support plate 21 also rotates and separates from the contact portion 40a of the pressing member 40, and the pressing member 4
0 is returned to the separation piece 30 side by the urging force of the second pressing spring 33.

The operation of the rotation of the paper support plate 21 during paper feeding and the accompanying movement of the pressing member 40 will be described later in detail.

Next, the separating mechanism 3 constructed as described above is used.
1, among the sheet feeding operations for feeding the sheet P into the multi-function device 1 one by one, a separating operation (see FIGS. 5, 10, and 11) for separating the sheet P one by one and the sheet P A sheet arranging operation (see FIGS. 6 to 9) for arranging a sheet into a predetermined state every time one sheet is separated will be described in detail with reference to FIGS. The sheet feeding operation shown in FIGS. 5 to 11 is looped, and the sheet arranging operation shown in FIGS. 6 to 9 is performed from the initial state of the separating operation shown in FIG. After the separation operation shown in the drawing, the sheet returns to the initial state of the separation operation shown in FIG.

In the initial state shown in FIG.
Is a state in which the sheet P is rotated most clockwise about the support shaft 39 (bottom dead center), and a space for inserting the sheet P is formed between the sheet support plate 21 and the sheet feeding roller 22. The rotating mechanism at this time is in the state shown in FIGS. 13D and 14, and receives the power from the cam 70 to rotate the paper support plate pressing lever 75 to press the paper support plate 21. . As a result, the protrusion 21 provided on the paper support plate 21
a abuts against a contact portion 40 a provided on the pressing member 40, and resists the urging force of the second pressing spring 33,
Is pressed down. In the initial state of this separation operation, the pressing between the separation piece 30 and the separation piece contact portion 67 is released by pressing down the pressing member 40, and the separation piece 3
As for the pressing force applied to 0, only the pressing force by the first pressing spring 32 is applied (first biased state). In the initial state of the separating operation, the non-feeding portion 22b of the feeding roller 22 is
The separation piece 30 is opposed to the sheet feeding roller 63 and only the separation pad 29 is in contact with the separation piece 30.

In the initial state of the separating operation shown in FIG.
When an instruction to feed the paper P is given by the CPU 52,
The separation mechanism 31 first pushes back the sheet P left between the sheet feed roller 22 and the separation piece 30 to the upstream side in the sheet conveyance direction at the time of the previous sheet feeding, and sorts the sheet P. Perform the operation. Note that during this sheet arranging operation, the roller shaft A
The rotation of the (first shaft) is in a stopped state, and the paper feed roller 22 is not operating. Hereinafter, the sheet arranging operation will be described in detail with reference to FIGS.

FIG. 6 shows an initial state of the above-described sheet arranging operation. As shown in FIG. 6, the paper return lever 50 is
A state in which the paper return lever 50 is rotated most clockwise about the paper return lever support shaft 68 (bottom dead center) and the paper return lever 50 is in contact with the sound deadening pad 45 is shown.

FIG. 7 shows the second stage of the above-mentioned sheet arranging operation. As shown in FIG. 7, from the initial state of the sheet arranging operation shown in FIG. 6, the sheet return lever support shaft 68 (second axis) the sheet return lever 50 rotates counterclockwise, and the separation piece pressing lever Reference numeral 48 denotes a state in which engagement is performed above the separation piece protruding portion 49 provided on the separation piece 30. At this time, the separation piece pressing lever 48 is configured to press the separation piece 30 downward through the separation piece projecting portion 49 while resisting the urging force of the first pressing spring 32. The roller 63 and the separation pad 29 are not in contact with each other, and the paper P pinched by the paper feed roller 63 and the separation pad 29
The pressing force has been released. Further, in the second stage operation from the initial state of the paper arranging operation, the paper P, from which the pressing force by the paper feed roller 63 and the separation pad 29 has been released, comes into contact with the leading end of the paper P and the first paper contact surface 61a. The paper return lever 50 is pushed back to the upstream side in the paper transport direction by the counterclockwise rotation of the paper return lever 50 while the angle formed by the paper return lever is maintained at a substantially right angle.

FIG. 8 shows the third stage of the above-described sheet arranging operation. As shown in FIG. 8, from the second stage of the paper arranging operation shown in FIG. 7, the paper return lever 50 is further rotated in the counterclockwise direction, so that the separation piece pressing lever 48 and the separation piece protrusion 49 are formed. The state in which the engagement is released and the sheet is rotated most counterclockwise about the sheet return lever support shaft 68 (top dead center) is shown. As a result of the disengagement of the separation piece pressing lever 48 and the separation piece protrusion 49, the separation piece 30 is brought into contact with the sheet feed roller 63 and the separation pad 29 again by the urging force of the first pressing spring 32. It has become. Further, in the second to third stages of the paper arranging operation, the paper P from which the pressing force by the paper feed roller 63 and the separation pad 29 has been released is in contact with the leading end of the paper P and the second paper contact surface 61b. The paper return lever 50 is pushed back to the upstream side in the paper transport direction by the counterclockwise rotation of the paper return lever 50 while the angle formed by the paper return lever is maintained at a substantially right angle.

FIG. 9 shows the fourth stage of the above-mentioned sheet arranging operation. As shown in FIG. 9, from the third stage of the sheet arranging operation shown in FIG. 8, the sheet return lever 50 is rotated clockwise, and the separation piece pressing lever 48 is moved below the separation piece protrusion 49. The state where it engaged is shown. At this time, the separation piece pressing lever 48 is moved by the separation piece protruding portion 49 against the biasing force of the first winding spring 46, and the separation piece pressing lever support shaft 69.
It is configured to be pushed down around the center,
As a result, the separation piece pressing lever 48 can smoothly pass below the separation piece protrusion 49 without releasing the pressing force of the sheet feeding roller 63 and the separation pad 29. After the fourth stage of the sheet sorting operation is performed, the sheet returning lever 50 further rotates clockwise to return to the initial state of the sheet sorting operation shown in FIG. End the operation. At this time, the paper return lever 50 is actuated by the urging force of the second winding spring 47.
Although the clockwise rotation is performed, the clockwise rotation of the paper return lever 50 is regulated by the sound deadening pad 45, so that the generation of the collision sound is satisfactorily prevented. During the above-mentioned sheet arranging operation, only the sheet return lever 50 rotates, and the sheet supply roller 22 and the sheet support plate 21 do not rotate.

By the sheet arranging operation described above with reference to FIGS. 6 to 9, the sheet P left at the separation point during the previous sheet feeding is rotated counterclockwise by the sheet return lever 50. , Is pushed back to the upstream side in the sheet transport direction, and is placed again on the sheet support plate 21. This allows
At the start of the later-described separation operation, the separation is always performed in a state in which the sheets are tied, and it is possible to satisfactorily prevent the double-feeding of the sheets P and the empty feeding.

Next, the separation operation of the sheet P by the separation mechanism 31 after the above-described sheet arranging operation is performed will be described with reference to FIGS. 5, 10, and 11. FIG. FIG. 10 shows the second stage of the separating operation, and FIG. 11 shows the third stage.

In the second stage (see FIG. 10) of the separating operation performed after executing the above-described sheet arranging operation, the sheet supporting plate 21 is moved from the initial state of the separating operation shown in FIG.
9, the paper feed roller 22 is rotated most counterclockwise (top dead center), and the paper feed roller 22 is rotated in the paper transport direction (counterclockwise), so that the paper P and the paper feed unit 22a can come into contact with each other. State. This is because the rotation mechanism rotates the roller shaft A counterclockwise gradually from the initial state shown in FIG. 14, so that the paper feed roller 22 rotates in the paper transport direction,
The cam 70 also rotates in the same direction, and the cam 70 shown in FIG.
Cam surface 70a and recess 75 of paper support plate pressing lever 75
a.

At this time, the protruding portion 21 a provided on the paper support plate 21 and the contact portion 40 a provided on the pressing member 40
Is released, and the separation piece contact portion 67 provided on the pressing member 40 presses the separation piece 30.
As a result, the separation pad 29 is urged toward the paper feed roller 22 by the two pressing springs, the first pressing spring 32 and the second pressing spring 33 (second pressing state), and when the paper P is separated. It is possible to obtain the necessary frictional resistance.

From the second stage of this separation operation, the paper P placed on the paper support plate 21 is fed to the separation pad 29 by the paper feed roller 22 further rotating in the paper transport direction (counterclockwise). Nipped by the paper feed unit 22a of the paper roller 22,
Only the paper P that comes into contact with the paper feed roller 22 is transported into the multi-function device 1. At this time, most of the paper P placed on the paper support plate 21 is prevented from flowing into the separation point by the separation claws 62 (see FIG. 4) provided at both ends in the paper width direction. A large amount of paper P does not flow into the point at the same time.

Further, from the second stage of the separating operation, the cam 7 is synchronized with the further rotation of the paper feed roller 22 in the counterclockwise direction.
0 also rotates counterclockwise, so that the cam surface 70a
It gradually deviates from 5a. During this time, there is no contact between the cam surface 70a and the concave portion 75a due to the gap provided between the cam surface 70a and the concave portion 75a. Therefore, the rotation of the paper support plate pressing lever 75 is prevented, and the paper support plate 21 The first pressing spring 32 and the second pressing spring 3
3, the energized state by both of them continues.

In the third stage of the separation operation shown in FIG. 11, the paper support plate 21 rotates clockwise about the support shaft 39 from the second stage of the separation operation shown in FIG.
The protruding portion 21a and the contact portion 40a come into contact with each other.
This is because when the roller shaft A further rotates in the counterclockwise direction, the paper feed roller 22 rotates in the paper transport direction (counterclockwise), and the paper P is transported to the transport roller, and the cam 70 is also rotated. 13 (a)-
This is realized by changing as shown in (d). That is, in the process shown in FIGS.
5 starts to rotate and presses the paper support plate 21, whereby the protrusion 21 a provided on the paper support plate 21 and the pressing member 4
0 starts to engage with the abutting portion 40a provided on the pressing member 40, and the separating piece abutting portion 67 provided on the pressing member 40 separates from the separating piece 30 from the second stage position of the separating operation. Move to the stage position. Thereby, the separation pad 30
The paper P is urged toward the paper feed roller 22 only by the first pressing spring 32 (first urged state).
This can reduce the back tension generated in the above.

After the third stage of the separating operation, the sheet supporting plate 12 further rotates clockwise to form the projecting portion 21a.
Pushes down the pressing member 40 via the contact portion 40a against the urging force of the second pressing spring 33, returns to the initial state of the separating operation shown in FIGS. 5 and 14, and ends the separating operation described above. I do. In the feeding operation including the separating operation and the paper arranging operation, the rotation of the paper support plate 21 about the support shaft 39 and the rotation of the paper return lever 50 about the paper return lever support shaft 68. The rotation of the paper feed roller 22 in the paper transport direction (counterclockwise direction in the figure) is such that the drive force of the drive motor 53 is received via a drive motor 53 and a gear train (not shown). I have.

When the manual paper is placed on the manual paper mounting table 65, the first manual film 43a and the second manual film 43b cause the paper P above the paper P placed on the paper support plate 21 to be higher. By being guided to
The sheet P is guided to the separation point in preference to the sheet P, and is conveyed to the inside of the multi-function device 1 via the conveyance roller 24.
Further, the second manual feed film 43b is configured to guide both ends in the width direction of the manual feed paper upward, whereby the manual feed paper is caught by the separation claw 62 described above, and the manual feed paper may be deformed. , Which prevents the inconvenience of causing empty transport. In addition, the manual paper loading table 65
The same processing as the above-described sheet feeding operation is performed when a manual sheet is placed on the sheet.

The paper P sandwiched between the separation piece 30 and the paper feed roller 22 by the separation mechanism 31 having the above-described structure is used when the paper return lever 50 rotates upstream in the paper transport direction. In order to push the sheet P back to the upstream side in the sheet conveying direction while pushing down the separation piece projecting portion 49 via the separation piece pressing lever 48 to separate the separation piece 30 and the paper feed roller 22, the load on the sheet P is reduced. I can't call it. In the initial stage of the sheet feeding operation, the separation piece 30 and the sheet feeding roller 22
In order to remove the paper P sandwiched between
The paper P can be satisfactorily prevented from being multi-fed without the paper P being accumulated between the paper P and the paper feed roller 22. Separation piece 3
Since the pressing force between the separation piece 30 and the paper feed roller 22 does not need to be increased so that the paper P does not accumulate between the paper feed roller 22 and the paper feed roller 22, the back tension can be reduced satisfactorily. Therefore, it is possible to prevent the paper transport accuracy from deteriorating due to the above.

Further, since the paper return lever 50 is configured to rotate about a different axis from the paper feed roller 22, the paper return lever 50 is not affected by the configuration and control of the paper feed roller 22 side.
It can be operated. For example, the paper feed roller 22
When the same shaft as that described above is used, the paper return lever 50 is rotated to the paper feed roller 22 and the like, and unnecessarily operating other components causes a problem in the posture of the paper. Although such a problem may occur, in the present configuration, such a problem can be reliably prevented.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various improvements and modifications can be made without departing from the gist of the present invention.

[0074]

As described above, according to the paper feeder of the first aspect, in order to push the paper back to the upstream side in the transport direction, the paper support is moved to the first position away from the paper feed roller. The paper holding state between the paper feed roller and the paper support unit is released in the above, but since the separation piece is urged toward the paper feed roller by the first urging state even after moving the paper support unit, It is reliably prevented that a plurality of sheets held diagonally press the separation piece by its weight and enter between the separation piece and the paper feed roller. Thereafter, when the sheet return lever is rotated by the driving force of the driving means, the separation piece urged by the first biasing state via the separation piece separating member is interlocked with the rotation, and the separation piece is separated from the sheet feeding roller. Although it is temporarily separated, a certain amount of force is required to separate the separation piece from the paper feed roller, and by interlocking with the rotation of the paper return lever that rotates by receiving the driving force from the driving unit. The separation pieces can be easily separated. When the paper return lever is rotated, the paper held between the separation piece and the paper feed roller is pushed back by the paper return lever to the upstream side in the transport direction. since rotated by a driving force of the driving means, the paper in a state of being coercive <br/> lifting obliquely can be pushed back against the force of gravity, without burdening the paper, better paper Can be pushed back to the upstream side in the transport direction. Then, by removing the paper between the separation piece and the paper feed roller, the paper is not piled up between the separation piece and the paper feed roller, so that it is possible to satisfactorily prevent double feeding of the paper, and In addition, it is not necessary to increase the pressing force between the separation piece and the paper feeding roller so that the paper is not accumulated between the separation piece and the paper feeding roller, and the back tension can be reduced.

According to the paper feeder of the second aspect, the switching between the first urging state and the second urging state is realized by the cooperation of the two urging members. The biasing state can be switched with a simple configuration, and
Since this switching is linked to the movement of the paper support, there is no need to provide a dedicated configuration for the switching.

According to the paper feeder of the third aspect, the engagement member disposed on the paper return lever and the protrusion formed on the separation piece are engaged with the rotation of the paper return lever. The separation allows the separation piece and the paper feed roller to be separated from each other, so that the sheet is reliably nipped by the separation piece and the paper feed roller, and the paper can be pushed back to the upstream side in the transport direction. Further, since the separating piece separating member is constituted by the protruding portion of the separating piece and the engaging member of the sheet return lever, it is not necessary to newly provide a dedicated member, so that the space can be effectively used and the cost rises. Can be suppressed.

According to the paper feeder of the present invention, when the paper return lever rotates upstream in the transport direction and pushes back the paper, the engagement lever passes through the upper surface of the protrusion. When the paper return lever returns to the downstream side in the transport direction, that is, returns to the initial position, the paper return lever avoids contact with the protruding portion. Since the sheet is guided along the lower surface, the sheet is engaged with the projecting portion only when the sheet is pushed back, so that the separation piece and the sheet feeding roller can be reliably temporarily separated.

According to the paper feeding device of the fifth aspect, in a state where the sheet is urged in one direction by the urging means, the sheet is brought into contact with the upper surface of the projecting portion and pressed down, thereby completing the sheet returning operation. When the paper return lever returns to the original position, it is not necessary to press the protrusion, so that the engagement lever moves against the urging force of the urging means so that the contact with the protrusion is prevented. Avoid it easily. With a simple configuration using this urging means, it is possible to realize the pressing / avoidance of the protruding portion by the engagement lever, and the switching of the separation / biasing between the separation piece and the paper feed roller.

According to the sheet feeding device of the sixth aspect, the first to fourth steps can be performed simply by rotating the second shaft in one direction and in the other direction. Is performed, and the sheet sandwiched between the separation piece and the sheet feeding roller can be satisfactorily pushed back to the upstream side in the transport direction without imposing a load on the sheet.

According to the paper feeder of the present invention, when the paper is pushed back to the upstream side in the transport direction, the contact surface which comes into contact with the leading end of the paper at a substantially right angle is provided at the end of the paper return lever. Is formed, when the paper is pushed back to the upstream side in the transport direction, the leading edge of the paper is always in contact with the contact surface substantially at a right angle, so that the paper can be pushed back well without bending or deforming the paper. Can be.

According to the paper feeder of the present invention, since the rotation range of the paper return lever is regulated by the regulating pad inside the paper cassette, the paper return lever is directly connected to the paper cassette. Because the paper return lever does not come into contact with the paper cassette without coming into contact with the paper cassette, the collision noise does not occur.

According to the paper feeder of the ninth aspect, before the paper is fed by the paper feed roller and the separating piece, the paper is pushed back by the paper return lever to the upstream side in the transport direction, that is, so-called tidying. Since the operation is performed, the paper in the paper cassette is always ready at the time of the paper feeding operation, and the separation and conveyance of each sheet can be favorably performed.

According to the paper feeder of the tenth aspect, compared with the case where the sheet return lever is operated at one location to press the separation piece at one location, the entire separation piece is pressed uniformly. The paper can be reliably separated from the paper feed roller, and the paper can be pushed back evenly without tilting as compared with the case where the paper is pushed back at one place.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a multifunction device according to an embodiment.

FIG. 2 is a schematic side cross-sectional view when a central portion of the multi-function device is cut along a sheet conveyance direction.

FIG. 3 is a block diagram of a control unit that executes various functions provided in the multi-function device.

FIG. 4 is a schematic plan view of the separating mechanism as viewed from above.

FIG. 5 is a schematic side sectional view of the separating mechanism as viewed from the side.

FIG. 6 is an enlarged side cross-sectional view of a main part of the separation mechanism.

FIG. 7 is a diagram showing a second stage of the paper arranging operation.

FIG. 8 is a diagram illustrating a third stage of the paper arranging operation.

FIG. 9 is a diagram showing a fourth stage of the paper arranging operation.

FIG. 10 is a diagram illustrating a second stage of the separating operation performed after the sheet arranging operation is performed.

FIG. 11 is a diagram showing a third stage of the separating operation.

FIG. 12 is an explanatory diagram of a rotation mechanism of a paper support plate.

FIG. 13 is an explanatory diagram of a rotation mechanism of a paper support plate.

FIG. 14 is an explanatory diagram of a rotation mechanism of a paper support plate.

[Description of Signs] 1 Multi-function device 2 Recording device 3 Paper cassette 5 Reading device 6 Operation panel 9 Document mounting table 10 Document guide 15 Recording head 18 Carriage 19 Ink cartridge 21 Paper support plate 21a Projecting portion 22 Feeding roller 22a Feeding paper Unit 22b Non-paper feed unit 24 Conveyance roller 25 Discharge driven roller 26 Discharge drive roller 27 Paper discharge tray 29 Separation pad 30 Separation piece 31 Separation mechanism 32 First pressing spring 33 Second pressing spring 34 Image reading scanner 39 Support shaft Reference Signs List 40 Pressing member 40a Contact portion 41 Separator support shaft 48 Separator press lever 49 Separator projecting portion 50 Sheet return lever 61a First sheet contact surface 61b Second sheet contact surface 62 Separation claw 63 Feed roller 64 Manual paper guide 65 Manual paper loading table 66 Paper slot 67 Separating piece contact part 68 Paper return lever support shaft 69 Separation piece pressing lever support shaft 70 Cam 70a Cam surface 75 Paper support plate pressing lever 75a Depressed portion 75b Lever portion 75c Contact portion A axis

Claims (10)

(57) [Claims] 1. A sheet feeding roller driven by a driving unit to feed a sheet in a predetermined conveying direction, a separating piece abutting on the sheet feeding roller to separate the sheets one by one, and an upstream side in the conveying direction. A plurality of sheets are held obliquely with the upward direction, the downstream side in the transport direction as the downward direction, and movably disposed between a first position away from the paper feed roller and a second position approaching the paper feed roller. A sheet supporting portion, a first urging state in which the separation piece is urged toward the paper feed roller by the first urging force, and the separation piece is directed toward the paper feed roller by a second urging force larger than the first urging force. An urging member capable of switching between a second urging state and a second urging state; a separating member separating member for separating the separating member from the sheet feeding roller against the urging force of the urging member; And a pair of paper return levers rotatable at a position near the separation piece. Comprising a chromatography, and each separating a sheet of the paper, firstly, the paper feed the sheet supporting portion is moved to the sheet supporting portion in the first position from the second position B
In conjunction with the Rukoto is separated from the over La, with the Ru weaken the urging force against the separation pad is switched to the biasing member to the first urging state the biasing force from the second biasing state of the separation pad, the The paper return lever is positioned at the downstream side in the transport direction, and subsequently, in conjunction with the rotation of the paper return lever to the upstream side in the transport direction by the driving force from the driving unit, the first bias state is set. the partial separation pieces are urged
Temporarily separate from the paper feed roller via the separating member
A sheet feeding device for releasing the urging force on the separation piece and pushing the sheet on the sheet supporting portion back to the upstream side in the transport direction by further rotating the sheet return lever. 2. The urging member, comprising: a first urging member capable of constantly urging the separation piece toward a paper feed roller with a predetermined urging force; and a separate urging member separate from the first urging member. A second urging member provided, wherein the switching from the second urging state to the first urging state is interlocked with the movement of the paper support unit between the first position and the second position. 2. The sheet feeding device according to claim 1, wherein the second urging member is switched between a position where the second urging member can cooperate with the first urging member and a position where the second urging member cannot cooperate. 3. The separation piece separating member is disposed on the protrusion formed on the separation piece and on the paper return lever, and is interposed through the protrusion based on the rotation of the paper return lever on the upstream side in the transport direction. The sheet feeding device according to claim 1, further comprising: an engagement member that separates the separation piece from a sheet feeding roller. 4. The engaging member includes an engaging lever rotatably attached to a paper return lever, and the engaging lever is configured to rotate when the paper return lever rotates upstream in the transport direction. By pressing the upper surface of the protrusion, the separation piece is temporarily separated from the paper feed roller, and when the paper return lever is rotated downstream in the transport direction, the protrusion is released from the pressed state. The sheet feeding device according to claim 3, wherein the sheet feeding device returns to an original position while being guided along the lower surface. 5. The engaging lever is always urged in one direction by an urging means, and when guided along the lower surface of the projection, against the urging force of the urging means. The sheet feeding device according to claim 4, wherein the sheet feeding device passes through the lower surface of the protrusion by retracting in the other direction. 6. A series of operations for pushing back the sheet by the sheet return lever includes an initial stage of holding the sheet return lever at a position most rotated to the downstream side in the transport direction, and the second shaft rotating in one direction. By starting the movement, the sheet return lever is rotated to the upstream side in the transport direction, so that the engagement lever presses the upper surface of the protruding portion to temporarily separate the separation piece from the sheet supply roller and return the sheet. A second stage in which the sheet is pushed back to the upstream side in the transport direction by rotation of the lever; and a sheet return lever is pivoted to the most upstream side in the transport direction, and the pressing of the engaging lever to the projecting portion is released, whereby the separation piece is released. And the second shaft starts rotating in the other direction, the paper return lever is rotated downstream in the transport direction, and the engagement lever contacts the protruding portion. When making contact, the engagement lever retreats downward. The sheet feeding device according to claim 4, further comprising: a fourth step of passing while being guided along the lower surface of the protrusion. 7. An end surface of the sheet return lever is provided with a contact surface for continuously pushing back the sheet while abutting substantially perpendicular to the leading end of the sheet when pushing back the sheet. The sheet feeding device according to claim 1. 8. A paper cassette for storing the papers in a stacked state, and a regulating pad provided inside the paper cassette within a rotation range of the paper return lever and for regulating a rotation range of the paper return lever. The sheet feeding device according to any one of claims 1 to 7, further comprising: 9. A series of operations for pushing back the paper by the paper return lever operates the first shaft to rotate the paper feed roller, and starts separation of the paper stacked in the paper cassette. 7. The paper feeding device according to claim 6, wherein the feeding is performed before. 10. The sheet feeding device according to claim 1, wherein the projecting portions are provided at both ends of the separation piece, and a sheet return lever is provided corresponding to the projecting portions.