JP2009249089A - Paper feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder sharing driving force for a paper returning claw with another mechanism, and capable of properly controlling the timing of movement of the paper returning claw without damaging paper. <P>SOLUTION: A spring clutch 50 is disposed on a path supplying driving force to the paper returning claw 40. The spring clutch 50 is rotated by the driving force from a driving gear, and stopped by locking an armature 55 to first and second stoppers 53, 54. Rotations of the spring clutch 50 is converted into reciprocating movement of the paper returning claw 40 by a cam 52 rotating integrally with the spring clutch 50 and a cam follower 45 integrated with the paper returning claw 40. The armature 55 is controlled by a controlling portion 90 to move at proper timing so as to prevent the paper returning claw 40 from damaging the paper. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a paper feeding device, and more particularly to a paper feeding device having a paper return claw.

  There is a so-called multifeed problem in which two or more sheets are simultaneously conveyed in a mechanism for conveying sheets one by one from the sheet loading unit for printing in a printing apparatus or the like. Is conventionally known. Various measures for solving this double feed problem include the use of a separation pad, for example.

  A separation pad is disposed at a position facing the sheet feeding roller, and this separation pad applies a frictional force in a direction opposite to the conveying force to the second and subsequent sheets, thereby suppressing double feeding. However, the paper whose double feed is prevented by the separation pad remains outside the paper placement section and stops near the paper feed roller. It may adversely affect stable paper feeding.

  Therefore, there is a method of using a paper return claw for the purpose of achieving stable paper feeding. According to this measure, even when the paper stops near the paper feed roller, the paper return claw arranged on the paper transport path hooks the paper on the claw and moves it upstream. Push back to the part. Thereby, a stable paper feeding operation can be continued. In many cases, such a sheet return operation by the return pawl is regularly performed every time a predetermined number of sheets are conveyed.

  As a conventional technique related to the paper return claw, for example, in Patent Document 1 below, the medium return mechanism can be operated in a compact manner by adopting a structure in which the operation area of the medium return mechanism does not protrude from the main body of the medium feeding device. A medium feeding device that can perform recording, a recording device including the medium feeding device, and a liquid ejecting apparatus are disclosed.

JP 2005-280925 A

  In order to make the paper feeder compact, integrate functions, and reduce costs, it is desirable to share a drive source such as a motor that drives the paper return pawl with a drive source that drives other mechanisms of the paper feeder. . In fact, in recent years, the drive source of the mechanism for lifting the paper and pressing the paper against the paper feed roller in the paper placement unit and the drive source of the paper return claw are often shared.

  When the drive source of the paper return claw is shared with the drive source of another mechanism, the timing of starting and ending movement generally differs for each mechanism, so it does not match the timing of movement required for the paper return claw. There is a possibility that the movement of the paper return claw may not be desirable. For example, when the paper return operation of the paper return claw is started too early, the paper return claw may rub the back surface of the topmost paper. At this time, depending on the type of paper, such as strong stiffness of the paper, the back surface of the paper may be scratched, which is not desirable.

  If the timing of the movement of the paper return claw is determined uniformly, the paper return claw may scratch the back surface when the paper size of the uppermost paper is large. Therefore, it is necessary to appropriately control the timing of the movement of the paper return claw corresponding to the paper size and the like. However, as described above, the timing of the movement is uniformly set under the situation where the driving force is shared with other mechanisms. It may be said that the current situation is stipulated. Therefore, the development of a mechanism for appropriately controlling the timing of movement of the sheet return claw while sharing the driving force with other mechanisms is an unsolved problem.

  In view of the above problems, the problem to be solved by the present invention can appropriately control the timing of the movement of the paper return claw while having a configuration in which the driving force for the paper return claw is shared with other mechanisms. It is to provide a paper feeding device.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a paper feeding device according to the present invention includes a paper placement unit for placing paper, a paper transport path through which the paper is transported, and a paper placed on the paper placement unit. A sheet feeding device including a sheet feeding roller that feeds the sheet to the sheet conveying path, and upstream of a sheet other than the topmost sheet in the sheet stacking unit that is stopped while being fed by the sheet feeding roller; A sheet return claw for performing a sheet return operation to be returned to the side, a drive unit for supplying a drive force to a mechanism constituting the sheet feeding device including the sheet return claw, and a drive force from the drive unit to the sheet return claw A clutch disposed on a transmission path; and sheet return claw control means for controlling the sheet return operation of the sheet return claw by controlling connection and disconnection of the clutch. To do.

  As a result, the clutch is arranged on the path for transmitting the driving force from the drive unit to the paper return claw, and the paper return claw control means controls the connection and disconnection of the clutch to control the paper return operation of the paper return claw. Therefore, the paper return operation of the paper return claw can be controlled at an appropriate timing while sharing the driving force for the paper return claw with other mechanisms. Therefore, by not providing a new motor or other drive source for the paper return pawl, while achieving compactness and cost reduction, the paper return operation is optimized and the paper is damaged or more than necessary for the paper return operation. It is possible to avoid wasting time.

  Further, the paper return claw control means moves the paper return claw from a side not contacting the paper feed roller to a position close to the paper surface on the uppermost paper being fed by the paper feed roller. The first movement control means for moving and stopping the paper, and the paper return claw is moved further upstream from the position moved and stopped by the first movement control means. It is good also as a structure provided with the 2nd movement control means to perform the said paper return operation | movement returned to the upstream side.

  As a result, the first movement control means moves the paper return claw to a position close to the uppermost paper on the way of being fed by the paper feed roller and stops it, and the second movement control means stops the paper return claw. The claw can be moved further upstream from the position where it has been moved and stopped by the first movement control means, and the sheets other than the topmost can be returned to the upstream side. Accordingly, the sheet return claw is moved in two stages and stopped at a position close to the uppermost sheet moved by the first movement control means, so that the sheet return operation can be quickly started from this position. Further, at the same position, a sheet other than the uppermost sheet that has passed through the sheet feeding roller can be received by a nail and can play an auxiliary role in suppressing double feeding.

  Further, for each paper size or paper type of the paper, according to the storage unit that stores information on the start timing of the paper return operation in which the paper return operation does not damage the paper, and according to the paper size or paper type, The paper return operation start timing information stored in the storage unit may be configured to include a determination unit that determines the start timing of the paper return operation by the paper return claw control unit.

  Accordingly, the determining unit is configured to control the paper return claw control unit according to the information on the start timing of the paper return operation in which the paper return operation for each paper size or paper type stored in the storage unit does not damage the paper. The start timing of the paper return operation is determined. Therefore, it is possible to appropriately set the timing of the paper return operation according to the paper size and paper type, and the paper return claw can prevent the paper from being damaged by the paper return operation. Furthermore, the paper return operation may be a start timing that avoids unnecessarily lowering the paper feed speed due to the paper return operation at the same time that the paper return operation does not damage the paper. As a result, it is possible to achieve sheet return without damaging the sheet by the start timing determined for each sheet size and sheet type while suppressing a decrease in sheet feeding speed.

  The information on the start timing of the paper return operation stored in the storage unit is information on the start timing of the paper return operation for each paper size so that the paper and the paper return claw do not contact in the paper return operation. It may be information.

  As a result, the start timing of the paper return operation for preventing the paper and the paper return claw from contacting each other in the paper return operation is stored in the storage unit for each paper size, and this is used by the determining means. Even when a size paper is used, it is possible to prevent the paper from being damaged in the paper returning operation.

  In addition, the information on the start timing of the paper return operation stored in the storage unit is that the paper type is a paper type in which the paper surface is damaged in contact with the paper return claw in the paper return operation. The sheet return operation start timing for preventing the sheet and the paper return claw from contacting each other in the paper return operation for each paper size, and the paper type is the same as the paper return claw in the paper return operation. In the case of a paper type that does not damage the paper surface in contact, the information may be information on the start timing of the paper return operation that allows the paper and the paper return claw to contact in the paper return operation. Good.

  As a result, for paper types that are easily damaged by contact with the paper return claw, such as so-called strong paper, the paper return claw does not contact the paper and the paper return claw, while the flexibility is high. For paper types that are not easily damaged by contact with the paper, the paper and the paper return claw are allowed to contact. Therefore, since the paper return operation can be started quickly for paper types that are not easily damaged by contact with the paper return claw, it is possible to suppress a decrease in paper feed speed due to the paper return operation.

  A sensor arranged on the paper transport path for detecting the paper position of the paper to be transported, and information on the paper position is used in determining the start timing of the paper return operation by the paper return claw control means; The position information may be information on the paper position detected by the sensor.

  As a result, the paper return claw control means controls the paper return operation according to the paper position detected by the sensor, so that the paper return operation can be controlled based on accurate paper position information. Therefore, it is possible to reduce the possibility that the paper return claw will accidentally damage the back surface of the paper due to the uncertain paper position information.

  It is good also as a structure provided with the paper press part which is arrange | positioned under the said paper mounting part and presses a paper to the said paper feeding roller, and the said drive part supplies a driving force to the said paper press part.

  In the configuration of the paper feeding device, the paper return claw is often adjacent to the paper pressing portion. Therefore, sharing a drive source for driving the paper return claw and the paper pressing unit has great advantages in terms of downsizing of the apparatus, integration of functions, and cost reduction.

  Embodiment 1 of the present invention will be described below with reference to the drawings. First, FIG. 1 is a cross-sectional view showing an outline of a sheet feeding device 1 in Embodiment 1 of the present invention. The basic structure of the paper feeding device 1 is to transport the paper 80 placed in the paper feeding cassette 10 (paper placement unit) to the paper conveyance path 30 (conveyance path) by the rotation of the half-moon roller 20 (paper supply roller). To do.

  The paper feed cassette 10 includes a bottom plate 11 and a bottom plate moving unit 12. When the paper 80 is fed, the bottom plate 11 is pushed up by the bottom plate moving unit 12, and the paper 80 is moved to the half moon roller 20. Is pressed. Thereby, the paper feeding operation by the half-moon roller 20 becomes possible.

  The rotation and stationary of the half-moon roller 20 are controlled by the control unit 90. The control unit 90 includes a storage unit 91 that stores programs and the like necessary for processing described below, and an input / output unit 92 for input / output from the user. The control unit 90 is used in addition to the control of the half-moon roller 20, which will be described later.

  The half-moon roller 20 conveys the paper 80 to the conveyance path 30 by rotating counterclockwise in FIG. At that time, the separation pad 35 functions. As the half-moon roller 20 rotates, a plurality of sheets 80 including the uppermost sheet among the sheets placed on the sheet feeding cassette 10 may be conveyed. The transported paper 80 is guided toward the transport path 30 by the rotation of the half-moon roller 20 while being sandwiched between the half-moon roller 20 and the separation pad 35.

  The separation pad 35 is made of a material having a large friction coefficient, and the friction force generated thereby stops the progress of the plurality of sheets 80 sandwiched between the half-moon roller 20 and the separation pad 35 other than the uppermost sheet 81, The purpose is to transport only the first sheet 81 to the transport path 30.

  1 is provided with a paper return claw 40 (return claw). As described above, the plurality of sheets 80 are simultaneously conveyed by the half-moon roller 20 to a position where the separation pad 35 is located. Even if the sheet 80 other than the topmost sheet is not advanced by the separation pad 35 and is not double-fed, for example, when the next sheet 80 is fed, the sheet 80 is not in the sheet feeding cassette 10 and its leading end is already half a month. The roller 20 may have reached a certain position.

  In this way, if the paper feeding is continued without the leading end positions of the paper 80 being aligned, the possibility of double feeding increases, which may adversely affect the paper feeding. Therefore, the return claw 40 performs an operation of returning the paper 80 that has normally been out of the paper feed cassette 10 at a certain interval to the paper feed cassette 10.

  In this embodiment, as will be described below, the return claw 40 is moved and stopped using the control unit 90 described above. At this time, the driving force for moving the return claw 40 is shared with the driving force of the bottom plate moving unit 12 in this embodiment, for example. The spring clutch 50 is interposed in a mechanism that transmits the driving force to the return claw 40. The movement of the return pawl 40 is controlled by the connection and disconnection of the spring clutch 50.

  As shown in FIG. 1, a cam 52 is formed in the spring clutch 50, and both rotate integrally around the shaft 51 in the illustrated clockwise direction. The spring clutch 50 is formed with a projecting first stopper 53 and a second stopper 54. An armature 55 that is engaged with the first stopper 53 and the second stopper 54 is disposed. The armature 55 rotates about the axis 56. The rotation of the armature 55 is controlled by the control unit 90.

  The shaft 51 of the spring clutch 50 described above is also a rotation shaft of the drive gear 60. The drive gear 60 is shown in FIG. FIG. 4 is a perspective view of a part of FIG. 1 as viewed from the back side, and shows the positional relationship between the drive gear 60 and the spring clutch 50. Due to the well-known spring clutch structure, the armature 55 is not locked to either the first stopper 53 or the second stopper 54 by the frictional force between the contact surfaces of the drive gear 60 and the spring clutch 50. In this case, when the drive gear 60 rotates, the spring clutch 50 also rotates together.

  However, when the armature 55 is locked to either the first stopper 53 or the second stopper 54, the spring clutch 50 is stationary regardless of the rotation of the drive gear 60. As described above, in this embodiment, for example, the driving force of the driving gear 60 may be transmitted to the bottom plate moving unit 12 by a mechanism (not shown) to give the driving force. The return claw 40 is formed with a cam follower 45 that rotates around the shaft 43 integrally with the return claw 40.

  A flowchart of the return claw movement control process in the sheet feeding device 1 having the above configuration is shown in FIG. 5 and will be described below.

  First, in step S10, a paper feed is instructed. For example, this command may be given by an input using the input / output unit 92 of the user. Thereby, the drive gear 60 starts rotation in S20. Therefore, as described above, the driving force of the driving gear 60 is transmitted to the bottom plate moving portion 12, the bottom plate 11 is raised, and the paper 80 is pressed against the half-moon roller 20. Then, the half-moon roller 20 starts to rotate in response to the paper feed command, and starts feeding the uppermost paper 80.

  Next, a first movement control process is performed in S30. Details of this processing are shown in FIG. 6 and will be described later. With this process, the return claw 40 moves from the position 101 shown in FIG. 1 to the position 102 shown in FIG. 2 and stops. The state at the stage when the procedure of S30 is completed is shown in FIG. In the following description, the position 101 of the return claw 40 shown in FIG. 1 is the first position, the position 102 of the return claw 40 shown in FIG. 2 is the second position, and the position 103 of the return claw 40 shown in FIG. Is referred to as the third position. The return claw 40 may be set so that the position when the external force is not applied is set to the first position 101 by the action of a spring (not shown), for example.

  Next, in S40, it is determined whether or not to execute paper return. This determination may be made based on, for example, the input of the number of sheets to be returned by the user using the input / output unit 92 in advance and the information being returned.

  Next, in S50, the second movement control process is performed. Details of this processing are shown in FIG. 7 and will be described later. By this processing, the return claw 40 moves from the second position 102 shown in FIG. 2 to the third position 103 shown in FIG. 3, and then the movement direction is reversed, so that the first position shown in FIG. Move to 101 and stop. By such movement, the paper 80 that has stopped near the half-moon roller is pushed back toward the paper feed cassette 10.

  Next, in S60, it is determined whether or not the predetermined number of sheets has been completed. For example, the predetermined number of sheets fed may be input in advance by the user using the input / output unit 92. When the predetermined number of sheets has been completed (S60: YES), the process proceeds to S70. If the predetermined number of sheets has not been completed (S60: NO), the process returns to S30 again and the above-described processing is repeated. In S70, since the predetermined number of fed sheets has been completed, the drive gear 60 is stopped. The above is a flowchart of the entire return claw movement control process.

  As described above, the detailed procedure of the S30 first movement control process is shown in FIG. 6, which will be described next.

  First, in S31, the armature 55 is rotated to the non-locking position about the shaft 56. The non-locking position is the position of the armature 55 shown in FIG. 3, and the locking to the first stopper 53 is released by the presence of the armature 55 at this position. Thereby, in S32, a driving force is transmitted to the spring clutch 50 by friction from the rotating drive gear 60, and the spring clutch 50 and the cam 52 start to rotate together. With this rotation, the cam 52 presses the cam follower 45 and the return claw 40 starts moving.

  In step S33, the armature 55 is moved to the locking position. The locking position is the position of the armature 55 in FIG. As a result, the armature 55 is locked to the second stopper 54 in S34, and the rotation of the spring clutch 50 and the cam 52 is stopped. Then, the return claw stops at the second position 102. This state is shown in FIG. FIG. 2 shows a state in which the uppermost sheet 81 and the second sheet 82 are simultaneously fed by the half-moon roller 20. In the drawing, the return claw 40 at the second position 102 receives the second sheet 82. For example, the time interval from step S31 to step S33 may be appropriately determined in advance so that the second stopper 53 is locked in step S33. The above is the first movement control process.

  The detailed procedure of the S50 second movement control process is shown in FIG. 7, which will be described next.

  First, in S51, the start of the sheet returning operation is determined. Details of this procedure will be described later. Next, in S53, the armature 55 is rotated to the non-locking position about the shaft 56. Since the armature 55 is in the non-locking position, the locking to the second stopper 54 is released. Thereby, in S54, a driving force is transmitted from the rotating drive gear 60 to the spring clutch 50 by friction, and the spring clutch 50 and the cam 52 start to rotate together.

  With this rotation, the cam 52 presses the cam follower 45 and the return claw 40 also starts to move from the second position 102. In step S55, the armature 55 is moved to the locking position. During this time, the cam 52 continues to move the return pawl 40 by pressing the cam follower 45, and reaches the third position 103 in S56. The sheet returning operation is performed by the movement from the second position 102 to the third position 103. FIG. 3 shows a state in which the second paper 82 is returned to the paper feed cassette 10 by the return claw 40. After the return claw 40 reaches the third position 103, the return claw 40 changes its direction and moves to the first position 101.

  In step S57, the armature 55 is engaged with the first stopper 53, and the rotation of the spring clutch 50 and the cam 52 is stopped. The return claw 40 stops at the first position 101. This state is shown in FIG. The time interval from step S53 to S55 may be determined appropriately in advance, for example, so that the first stopper 53 is not locked in S55. The above is the second movement control process.

  Details of the S51 paper return operation start process described above are shown in FIG. 8, which will be described next. First, in S510, the paper size information is confirmed. For example, the paper size information input from the user at the start of the paper feed process using the input / output unit 92 and stored in the storage unit 91 may be called. In step S <b> 513, information on the start timing of the sheet returning operation is called from the storage unit 91.

  For example, this information includes, for each paper size, the rotation angle at which the return claw 40 does not contact the uppermost paper 81 even when the paper return operation is started at the rotation angle of the half-moon roller 20 from the start of paper supply. The timing may be calculated in advance and stored in the storage unit 91. At this time, when the timing at which the return claw 40 does not come into contact with the uppermost sheet 81, the sheet return operation may be started immediately. Thereby, it is possible to avoid unnecessarily lowering the paper feed speed.

  Next, when the timing coincides with the start timing information obtained in S513, the control unit 90 determines the start of the sheet returning operation in S517. The above is the paper return operation start processing.

  Next, Example 2 will be described. The second embodiment is the same as the first embodiment except that the flowchart of FIG. 8 is replaced with the flowchart of FIG. 9 in the first embodiment. Hereinafter, a flowchart of the paper return operation start process of FIG. 9 will be described. 9 differs from FIG. 8 in that not only the paper size but also the paper type is considered.

  First, in step S511, paper size information and paper type information are confirmed. For example, the paper size information and the paper type information input from the user using the input / output unit 92 and stored in the storage unit 91 at the start of the paper feed process may be called. In step S <b> 514, information on the start timing of the sheet return operation is called from the storage unit 91.

  This information is, for example, the rotation angle at which the return claw 40 does not damage the uppermost sheet 81 even if the sheet return operation is started at the rotation angle of the half-moon roller 20 from the start of sheet feeding for each sheet size and sheet type. May be calculated in advance as the timing for starting the paper return operation and stored in the storage unit 91.

  In this case, for example, when the paper type is highly likely to be damaged when the return claw 40 comes into contact with the uppermost paper 81 during the paper return operation, such as strong paper stiffness, The start timing may be such that the uppermost sheet 81 does not come into contact.

  If the paper type is unlikely to be damaged even when the return claw 40 contacts the uppermost paper 81 during the paper return operation, such as the flexibility of the paper, the return claw 40 The start timing may be at which the uppermost sheet 81 may come into contact. Therefore, in the case of the latter type of paper, the start of the paper return operation can be accelerated, so that a decrease in the paper feed speed due to the paper return operation can be suppressed.

  Next, when the timing coincides with the start timing information obtained in S514, the control unit 90 determines the start of the sheet returning operation in S518. The above is the paper return start process in the second embodiment.

  Next, Example 3 will be described. FIG. 11 is a cross-sectional view showing an outline of the paper feeding device 2 in the third embodiment. The difference between the sheet feeder 2 and the sheet feeder 1 described above is the arrangement of the sensor 70. The sensor 70 detects the leading edge of the sheet 80 conveyed on the conveyance path 30 and sends the information to the control unit 90.

  The processing procedure in the third embodiment is also shown in FIGS. 5, 6, and 7 as in the first and second embodiments. 11 is a view corresponding to FIG. 1, and illustrations corresponding to FIG. 2 and FIG. 3 are omitted. In the second embodiment, the return claw 40 moves to the same position as in FIG. 2 and FIG. .

  In the third embodiment, the flowcharts of FIGS. 5, 6, and 7 are used. A flowchart of the S50 sheet return operation start process in the third embodiment is shown in FIG. In the flowchart of FIG. 10, the processing of S511, S514, and S518 is the same as the processing of the same number in FIG. Only the procedure of next S516 is that FIG. 10 is different from FIG. Sensor 70 is used in this procedure.

  S516 indicates the timing at which the sensor 70 detects the end of the uppermost sheet 81. For example, what angle the half-moon roller 20 rotates from the detection in S516 may be derived in advance as to the start timing obtained in S514. When the timing comes, the control unit 90 determines the start of the sheet returning operation in S518.

  In the third embodiment, more accurate information on the position of the uppermost sheet 80 is obtained by detecting the leading edge of the sheet by the sensor 70, so that the accuracy at the start timing of the sheet returning operation in S518 is the rotation angle of the half-moon roller 40. The effect of improving compared with the case where it determines from only is acquired. The above is the third embodiment.

  In the above embodiment, the drive gear 60 constitutes a drive unit. The spring clutch 50 constitutes a clutch. The procedure of the return claw movement control process in FIG. 5 functions as a paper return claw control means. The procedure of the S30 first movement control process functions as first movement control means. The procedure of S50 second movement control processing functions as second movement control means. The procedures of S517 and S518 function as determination means. The bottom plate moving unit 12 constitutes a paper pressing unit.

Sectional drawing which shows the outline | summary of the paper feeder in Example 1 (however, a paper return nail | claw exists in a 1st position). Sectional drawing which shows the outline | summary of the paper feeder in Example 1 (however, a paper return nail | claw exists in a 2nd position). Sectional drawing which shows the outline | summary of the paper feeder in Example 1 (however, a paper return nail | claw exists in a 3rd position). The perspective view which shows a drive gear. The flowchart which shows a return claw movement control process. The flowchart which shows a 1st movement control process. The flowchart which shows a 2nd movement control process. 6 is a flowchart illustrating a paper return operation start process according to the first exemplary embodiment. 9 is a flowchart illustrating a paper return operation start process according to the second embodiment. 10 is a flowchart illustrating a paper return operation start process according to the third exemplary embodiment. Sectional drawing which shows the outline | summary of the paper feeder in Example 3 (however, a paper return nail | claw exists in a 1st position).

Explanation of symbols

1, 2 Paper feeding device 10 Paper feeding cassette (paper placement section)
11 Bottom plate 12 Bottom plate moving part (paper pressing part)
20 Paper feed roller 30 Transport path (paper transport path)
35 Separation pad 40 Paper return claw (return claw)
45 Cam follower 50 Spring clutch (clutch)
52 Cam 53 First Stopper 54 Second Stopper 55 Armature 60 Drive Gear (Driver)
80, 81, 82 Paper 90 Control unit 91 Storage unit 92 Input / output unit

Claims (7)

A paper supply section provided with a paper placement section for placing the paper, a paper conveyance path through which the paper is conveyed, and a paper feed roller for feeding the paper placed on the paper placement section to the paper conveyance path. A paper device,
A paper return claw that performs a paper return operation for returning to the upstream side a paper other than the topmost paper in the paper placement unit, which is stopped in the middle of being fed by the paper feed roller;
A driving unit for supplying a driving force to a mechanism constituting the paper feeding device including the paper return claw;
A clutch disposed on a path for transmitting a driving force from the driving unit to the paper return claw;
A paper feeding device, further comprising paper return claw control means for controlling the paper return operation of the paper return claw by controlling connection and disconnection of the clutch. The paper return claw control means includes
First movement control for stopping the sheet return claw by moving the uppermost sheet on the way being fed by the sheet feeding roller from the side not contacting the sheet feeding roller to a position close to the sheet surface. Means,
The paper return claw is moved from the position where it has been stopped by the first movement control means to move further upstream to perform the paper return operation for returning the paper other than the uppermost paper to the upstream side. The sheet feeding device according to claim 1, further comprising two movement control means. A storage unit that stores information on a start timing of the paper return operation in which the paper return operation does not damage the paper for each paper size or paper type of the paper;
Determining means for determining the start timing of the paper return operation by the paper return claw control means in accordance with the information on the start timing of the paper return operation stored in the storage unit according to the paper size or paper type. The sheet feeding device according to claim 1 or 2.   The information on the start timing of the paper return operation stored in the storage unit is information on the start timing of the paper return operation for each paper size so that the paper and the paper return claw do not contact in the paper return operation. The paper feeding device according to claim 3, which is information. Information on the start timing of the sheet return operation stored in the storage unit is as follows:
When the paper type is a paper type that damages the surface of the paper in contact with the paper return claw in the paper return operation, the paper and the paper return claw for each paper size are the paper return operation. Information on the start timing of the paper return operation for not contacting
When the paper type is a paper type that does not damage the surface of the paper in contact with the paper return claw in the paper return operation, the paper and the paper return claw are in contact in the paper return operation. The sheet feeding device according to claim 3, wherein the sheet feeding apparatus is information on a start timing of the sheet returning operation that is permitted. A sensor disposed on the paper transport path and detecting a paper position of the paper to be transported;
The paper position information is used in determining the start timing of the paper return operation by the paper return claw control means, and the paper position information is information on the paper position detected by the sensor. The sheet feeding device according to any one of the above. A sheet pressing portion disposed at a lower portion of the sheet placing portion and pressing a sheet to the sheet feeding roller;
The paper feeding device according to claim 1, wherein the driving unit supplies a driving force to the paper pressing unit.

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