JP5930606B2 - Paper feeder - Google Patents

Description

  The present invention relates to a paper feeding device mounted on an image forming apparatus, an image reading device, or the like, and more particularly, to a paper feeding device including a mechanism for raising and lowering a feeding roller that feeds a sheet on a paper feeding tray.

  2. Description of the Related Art Conventionally, a paper feeding device mounted on an image forming apparatus or a document reading apparatus main body is incorporated as a paper feeding unit of a sheet conveying device. The sheet conveying device in which the paper feeding device is incorporated separates the sheets one by one and feeds the document toward the image reading unit, and the paper feeding unit feeds the original. The original is supplied to a reading platen on the original reading apparatus, and includes a transport unit that discharges the image from the reading platen after reading the image, and a paper discharge unit that discharges the document discharged from the image reading unit to a paper discharge tray.

  A sheet feeding unit of a sheet conveying device includes, for example, a liftable feeding roller that feeds a sheet from a sheet feeding tray as in Patent Document 1, and a sheet feeding roller and a separation roller for separating the sheet fed from the feeding roller into one sheet Is provided. The feeding roller and the paper feed roller are drivingly connected to the drive motor via a drive transmission mechanism, and this drive transmission mechanism is configured to drive a plurality of gears and timing belts for driving transmission to the drive motor. It is comprised with the electromagnetic clutch for controlling transmission.

  In Patent Document 1, when the drive transmission of the drive motor is interrupted by the electromagnetic clutch, the end of the drive shaft of the paper feed roller is prevented in order to prevent the feeding roller from falling without being held at the standby position. The part is provided with a torque limiter.

JP 2002-249246 A

  However, in the sheet feeding unit of the sheet conveying apparatus as in Patent Document 1, a trilimiter is used as a means for preventing the feeding roller from dropping from the retracted position. Since a braking force is applied by the torque limiter, a large torque is required for the drive shaft of the paper feed roller. Therefore, the drive motor for driving the drive shaft of the paper feed roller had to be used with an expensive and large motor with a large output torque, resulting in a problem that the apparatus was increased in size and increased in cost. .

  The present invention has been made in view of the above problems, and can hold the feeding roller in the standby position even when the drive for raising and lowering the feeding roller is interrupted without increasing the size and cost of the apparatus. An object of the present invention is to provide a paper feeding device that can be used.

In order to solve the above-described problems, a sheet feeding device according to the present invention includes a sheet feeding tray on which a sheet is placed, a feeding roller that feeds a document in contact with the sheet on the sheet feeding tray, and one sheet fed out. A sheet feeding roller for separating and feeding the sheet and a separating unit, and a lifting unit that moves the feeding roller up and down to a feeding position where the feeding roller is in contact with the sheet and a standby position separated from the sheet. in the paper system, a holding member provided movably in the holding position and the retracted position retracted from the holding position to hold the standby position feed roller, the holding member is moved to increase the thus holding the position of the feeding roller, feeding to move to downward movement of the roller depending on the retracted position.

  Further, the paper feeding device of the present invention separates the fed sheet into one sheet by feeding a sheet feeding tray on which the sheet is placed, a feeding roller for feeding the document in contact with the sheet on the feeding tray. Separating means comprising a paper feeding roller for separating paper and a separating member, and a lifting / lowering means for moving up and down to a feeding position where the feeding roller is brought into contact with the sheet and a standby position separated from the sheet, A holding unit for holding the roller at the standby position is provided, the holding unit holding the feeding roller at the standby position, a holding member provided movably to the retracted position retracted from the holding position, and the holding member When the position of the holding member is closer to the holding position than the predetermined position, the holding member is biased toward the holding position. When the position of the holding member is closer to the retracted position than the predetermined position, the holding member is biased toward the standby position. Do The holding member is moved from the holding position to the predetermined position by the lowering of the feeding roller when the shaft of the feeding roller or a part of the support holder that supports the feeding roller comes into contact with the holding member. Then, the urging member moves from the predetermined position to the retracted position, moves to the predetermined position by the raising of the feeding roller, and moves from the predetermined position to the holding position by the urging member.

  According to the above invention, since the holding member that moves to the position where the feeding roller is held and the position where the holding is released is provided in conjunction with the raising / lowering operation of the feeding roller, the feeding roller is securely held at the standby position, Documents can be easily set on the paper tray.

1 is a cross-sectional view illustrating a document conveying device including a sheet feeding unit as a sheet feeding device according to the present invention and a document reading apparatus main body on which the document conveying device is mounted. FIG. FIG. 4 is a drive diagram illustrating a drive mechanism of a paper feed system in the document feeder according to the present invention. It is a control flowchart figure of the single-sided reading operation | movement in the original conveying apparatus which concerns on this invention. It is a control flowchart figure of the double-sided reading operation | movement in the original conveying apparatus which concerns on this invention. It is sectional drawing which shows the structure of the holding means which concerns on this invention. It is a perspective view which shows the structure of the holding means of the holding means which concerns on this invention. It is a schematic diagram which shows the effect | action of the holding means which concerns on this invention. It is a schematic diagram which shows the effect | action of the holding means which concerns on this invention. It is sectional drawing which shows the modification of the holding means which concerns on this invention.

  FIG. 1 is a cross-sectional view showing a document conveying apparatus having a sheet feeding portion as a sheet feeding apparatus according to the present invention and a document reading apparatus main body on which the document conveying apparatus is mounted. In the present embodiment, a document conveying device to which a paper feeding device according to the present invention is applied will be described.

  In FIG. 1, reference numeral 10 denotes a document conveying device mounted on the reading device main body 1. The document conveying device 10 is arranged so as to cover the upper surface of the document reading device main body 1 and is attached to the upper surface of the document reading device main body 1 by a hinge device (not shown) so as to be freely opened and closed.

  The document reading apparatus main body 1 irradiates a conveyed document with light from a light source 3 such as a lamp via a contact glass 2, reflects the reflected light by a plurality of mirrors 4, and performs photoelectric conversion by a reading unit such as a CCD 6. Read the original image. That is, the upper surface of the contact glass 2 constitutes a reading unit of the document reading apparatus main body 1. The document reading device main body 1 also includes a contact glass 5 having an area on which a document can be placed. The document placed on the contact glass 5 by opening and closing the document conveying device 10 includes a light source 3 and a mirror 4. By moving the light source unit in the sub-scanning direction, an image of the document can be read through the contact glass 5.

  The document conveying device 10 feeds out a document in contact with the uppermost surface of the document on the sheet feed tray 20, a paper feed tray 21 that can store a plurality of documents, a paper discharge tray 21 that stores the scanned document. A feed roller 30 that can be raised and lowered, a paper feed roller 31 that feeds the fed document, a separation pad 32 that is pressed against the paper feed roller 31 to prevent double feeding of the document, and a leading edge of the document are abutted against each other for alignment. After that, a pair of registration rollers 33 to be supplied onto the contact glass 2 and a pair of lead rollers 34 provided on the downstream side of the contact glass 2 and transporting a document passing through the contact glass 2 are provided. A pair of discharge rollers 35 is provided downstream of the pair of lead rollers 34 to discharge the document to the sheet discharge tray 21. The pair of discharge rollers 35, which will be described later, is a document in the duplex mode. The document is reversely rotated while the rear end side is nipped, and the document is switched back and conveyed to the registration roller pair 33 again.

  By driving and controlling the above-described rollers, the document on the paper feed tray 20 is guided along the paper feed path 23 from the paper feed roller 31 to the registration roller pair 33, and the registration roller pair 33 to the lead roller. The paper is discharged onto the paper discharge tray 21 from the paper discharge path 25 that leads from the lead roller pair 34 to the paper discharge roller pair 35 via the conveyance path 24 that reaches the pair 34. In the duplex mode, the document is switched back downstream of the paper discharge path 25 and guided to the registration roller pair 33 along the switchback path 26 from the paper discharge roller pair 35 to the registration roller pair 33. Is done. In this embodiment, a part of the upstream side of the switchback path 26 is also used as a part of the paper discharge path 25, and a part of the downstream side of the switchback path 26 is a part of the downstream side of the paper feed path 25. Also used as part.

  As shown in FIG. 1, the paper feed path 23 is formed with an upper guide plate 23a and a lower guide 23b facing each other, and the upper guide plate 23a is rotatably supported by a rotation fulcrum 70b. And can be opened and closed by being integrally rotated counterclockwise in the figure. The feeding cover 70 is provided with a feeding roller 30 and a feeding roller 31 so as to rotate integrally. As a result, the entire paper feed path 23 from the document tray 20 to the front of the registration roller pair 33 is opened so as to be continuously exposed, and the jammed document can be easily removed.

  Next, the drive configuration of each roller will be described. Each roller is driven by one drive motor MT that can be rotated forward and backward. The drive transmission mechanism of the drive motor MT includes a plurality of gears, pulleys, and a timing belt wound around the pulleys, and is disposed on the rear side of the document conveying device together with the drive motor MT.

  The drive transmission mechanism includes a paper feed system drive mechanism for transmitting drive to the feeding roller 30 and the paper feed roller 31, and a drive mechanism for transmitting drive to the drive roller of the registration roller pair 33 and the drive roller of the lead roller pair 34. It comprises a drive transmission mechanism for the transport system and a drive transmission mechanism for the paper discharge system that transmits the drive to the drive rollers of the paper discharge roller pair 35. The drive transmission mechanisms of the paper feed system, the transport system, and the paper discharge system are connected to a single drive motor MT as a drive means.

  As shown in FIG. 2, the drive mechanism of the paper feed system includes a first electromagnetic clutch ECL1 as a clutch means, and controls the first electromagnetic clutch ECL1 to drive the drive motor MT. 30 and the paper feed roller 31 are transmitted or cut off, and the driving of the feeding roller 30 and the paper feed roller 31 is controlled. The drive transmission mechanism of the transport system includes a second electromagnetic clutch ECL2 (not shown). By controlling the second electromagnetic clutch ECL2, the driving from the drive motor MT is controlled by the registration roller pair 33, Transmission to the read roller pair 34 is interrupted, and the drive is controlled by the registration roller pair 33 and the read roller pair 34. The drive transmission mechanism of the paper discharge system directly transmits the drive of the drive motor MT to the paper discharge roller pair 35, and is driven forward / reversely by the forward / reverse drive of the paper feed motor.

  The shaft 30a of the feeding roller 30 is rotatably supported by the support holder 40 as shown in FIG. One end of the support holder 40 is rotatably supported by the shaft 31 a of the paper feed roller 31. The support holder 40 is drivingly connected to the shaft 31a of the paper feed roller 31. The support holder 40 is configured to rotate in the vertical direction by forward and reverse rotation of the shaft 31a. Thus, the feeding roller 30 moves up and down to a feeding position where the feeding roller 30 comes into contact with the document and a standby position separated from the document. Further, a plurality of gears Z 1, Z 2, and Z 3 that transmit the rotation of the shaft 31 a of the paper feed roller 31 to the shaft 30 a of the feeding roller 30 are attached to the support holder 40. That is, the feeding roller 30 is configured to be moved up and down and rotated by support means including the shaft 30 a and the support holder 40.

  Note that the support holder 40 and the shaft 31a of the paper feed roller 31 are drivingly connected via a first spring clutch SCL1, and the first spring clutch SCL1 is brought into contact with the document when the feeding roller 30 is lowered. When a predetermined torque is generated, the drive connection is disconnected. On the other hand, a second spring clutch SCL2 is provided in the drive transmission mechanism that transmits the drive from the drive motor MT to the shaft 30a of the paper feed roller 30. In the second spring clutch SCL2, the driving roller 30 is lifted and comes into contact with the elastic member 75. When a predetermined torque is generated, the driving connection from the driving motor MT is cut off.

  Further, the first connection gear ZA and the second connection gear ZB are configured to be separated and connected as the paper feed cover 70 rotates. That is, when the paper feed cover 70 is in the open state, the first connection gear ZA and the second connection gear ZB are separated from each other, and when the paper feed cover 70 is in the closed state, the first connection gear ZA and the second connection gear ZB. Are connected.

  As shown in FIG. 1, an empty sensor S <b> 1 that detects that a document is placed on the paper feed tray 20 is disposed on the document tray 20. In addition, a registration sensor S2 for detecting an end portion of the fed document is disposed in front of the registration roller pair 33 in the sheet feeding path 23, and a lead sensor S3 is provided between the registration roller pair 33 and the contact glass 2. Has been placed.

  Each of these sensors S1, S2, and S3 is connected to a CPU that controls driving of the entire apparatus, and based on a detection signal from each sensor, the drive motor MT, the first electromagnetic clutch ECL1, and the second electromagnetic The clutch ECL2 is controlled.

  Next, the document transport control operation of the document transport apparatus having the above-described configuration will be described with reference to the flowcharts shown in FIGS.

  First, a description will be given of a single-side reading operation for reading one side of a document. When the empty sensor S1 is in an ON state, that is, when it is detected that a document is placed on the paper feed tray 20, the drive motor MT is driven to rotate forward. The first electromagnetic clutch ECL1 is turned on (ST1 to ST2). As a result, the feeding roller 30 and the paper feed roller 31 are rotationally driven, and the originals on the paper feed tray 20 are fed. When the registration sensor S2 detects the leading edge of the document, the registration operation 1 is executed (ST3, ST4).

  In the registration operation 1, the second electromagnetic clutch ECL2 is turned off and the registration roller pair 33 is stopped (ST31). At the same time, counting of the number of driving pulses of the motor is started, and when the number of pulses reaches a predetermined number of pulses A, the first electromagnetic clutch ECL1 is turned off (ST32 to ST33). As a result, the feeding roller 30 and the paper feed roller 31 are temporarily stopped. At this time, the leading edge of the document is abutted against the nip portion of the registration roller pair 33 to form a deflection, aligning the leading edge of the document, and correcting the skew (skew) of the document.

  The registration operation 1 is executed, and the second electromagnetic clutch ECL2 is turned on with the leading edge of the document abutting against the nip portion of the registration roller pair 33 (ST5). As a result, the registration roller pair 33 is rotationally driven, and the document is conveyed to the contact glass 2. The document conveyed to the contact glass 2 by the registration roller pair 33 is conveyed along the upper surface of the contact glass 2, and is discharged to the paper discharge tray 21 by the lead roller pair 34 and the paper discharge roller pair 35. Note that the document is read by the reading unit in the process of being conveyed along the upper surface of the contact glass 2. Further, after the second electromagnetic clutch ECL2 is turned on, when the trailing edge of the document conveyed by the registration roller pair 33, the lead roller pair 34, and the paper discharge roller pair 35 is detected by the registration sensor S2, the first electromagnetic clutch is again detected. The clutch ECL1 is turned on to start feeding the next original (ST6, ST2).

  Next, a description will be given of a double-sided reading operation for reading both sides of a document. When the empty sensor S1 detects that a document is placed on the paper feed tray 20, the drive motor MT is driven to rotate in the forward direction. The clutch ECL1 is turned on (ST11 to ST12). As a result, the feeding roller 18 and the paper feeding roller 19 are rotationally driven to feed the original. Similar to the single-sided reading operation, the registration operation 1 (ST4) is executed when the registration sensor S2 detects the leading edge of the document, and the leading edge of the document is aligned (ST13, ST14).

  When the leading edge of the document is aligned by the registration operation 1, the second electromagnetic clutch ECL2 is turned on, and the document is transported and passed through the contact glass 2 by the registration roller pair 33 (ST15). In the process of passing through the contact glass 2, the surface of the document is read by the reading means.

  The document that has passed through the contact glass 2 is fed onto the paper discharge tray 21 by the lead roller 34 and the paper discharge roller 35. Then, the number of drive pulses of the drive motor MT is counted from the time when the registration sensor S2 detects the trailing edge of the document, and when the count value reaches a predetermined number of pulses B, the drive motor MT is switched from forward rotation to reverse rotation ( ST16-18). As a result, the paper discharge roller pair 35 is switched from normal rotation to reverse rotation, and the original is switched back on the paper discharge path 25. The predetermined pulse number B described above is the drive pulse number of the drive motor MT corresponding to the distance from the registration sensor S2 to the predetermined position between the flapper 36 and the paper discharge roller pair 35.

  The document switched back by the discharge roller pair 35 is guided toward the registration roller pair 33 along the switch pack path 26. When the leading edge of the document is detected again by the registration sensor S2, registration operation 2 is executed (ST19 to ST20).

  In the registration operation 2, the second electromagnetic clutch ECL2 is turned off and the registration roller pair 33 is stopped (ST41). At the same time, counting of the number of drive pulses of the drive motor is started, and the drive motor MT is driven in reverse until the number of pulses reaches a predetermined number of pulses A (ST42). As a result, the leading edge of the document is abutted against the nip portion of the registration roller pair 33 to form a bend (registration loop), and the leading edge of the document is aligned. When the number of pulses of the drive motor MT reaches a predetermined number of pulses (pulse A), the drive motor MT is switched from the reverse drive to the normal drive (ST43).

  When the registration operation 2 is executed, the second electromagnetic clutch ECL2 is turned on (ST21). As a result, the resist roller pair 33 is driven to rotate forward, and the document is conveyed onto the contact glass 2 while being reversed. Then, the back side of the document is read by the reading means.

  Thereafter, the trailing edge of the document whose back side is read is detected by the registration sensor S2, and when the document is conveyed by a predetermined number of pulses B, the drive motor MT is switched from normal rotation to reverse rotation (ST22 to ST24). As a result, the paper discharge roller pair 35 is switched from forward rotation to reverse rotation. Then, when the rotation direction of the paper discharge roller pair 35 is switched, the document is switched back again in the paper discharge path 25 and sent toward the registration roller pair 33 along the switchback path 26. When the registration sensor S2 detects the leading edge of the document, the registration operation 2 (ST20) is executed again (ST25 to ST26).

  After the registration operation 2 is executed, the second electromagnetic clutch ECL2 is turned on (ST27). As a result, the registration roller pair 33 is rotationally driven, and the document is reversed and conveyed to the contact glass 2. Then, after passing through the contact glass 2, the original is conveyed to the paper discharge tray 21 by the lead roller pair 34 and the paper discharge roller pair 35. Note that the operations in steps 25 to 27 are operations for aligning the page order of the documents stored in the paper discharge tray 21. For this reason, reading of the document passing through the contact glass 2 is not performed here.

  When the trailing edge of the document reversed for page alignment is detected by the registration sensor S2, the first electromagnetic clutch ECL1 is turned on again to start feeding the next document (ST28, ST12).

  Here, the paper feed unit is provided with holding means for holding the feeding roller 30 in the upper standby position. 5 is a cross-sectional view showing the configuration of the holding means, FIG. 6 is a perspective view showing the configuration of the holding means, and FIGS. 7 and 8 are schematic views showing the operating state of the holding means.

  As shown in FIG. 5, the holding means allows the holding member 50 to abut against the feeding roller 30 to prevent it from descending, the holding position for holding the feeding member 50 in the retracted position, and the feeding roller 30 to be lowered. It comprises an urging spring 60 as an urging member for moving to the retracted position.

  The holding member 50 is formed in an L shape including a first portion 51 and a second portion 52 bent from the first portion 51. A rotation shaft 56 is provided on each side surface of the first portion 51 of the L-shaped holding member 50, that is, both side surfaces of the central corner of the holding member 50. The rotation shaft 56 is rotatably attached to a pair of rib-shaped shaft support portions 71 protruding inside the paper feed cover 70. The holding member 50 is provided with a regulating piece 59 that abuts against a protrusion 73 formed on the inner side of the paper feed cover 70 and regulates the clockwise rotation of the holding member 50. The counterclockwise rotation of the holding member 50 is restricted by the outer surface 53 of the second portion 52 of the L-shaped holding member 50 coming into contact with the protrusion 73 of the paper feed cover 70. In this embodiment, as shown in FIG. 7A, a sponge 74 is attached to a protrusion 73 formed on the inner side of the paper feed cover 70, and the regulating piece 54 of the holding member 50 and one end side of the holding member 50 are attached. The impact and noise when the outer surface 50c of the portion 50a abuts against the protrusion 63 is reduced.

  One end of the biasing spring 60 is attached to a mounting pin 57 provided in the first portion 51 of the L-shaped holding member 50. On the other hand, the other end of the urging spring 60 is attached to the hook 72 a of the attachment portion 72 protruding from the inside of the paper feed cover 60. The attachment pin 57 and the attachment portion 72 are provided so as to sandwich the rotating shaft 56, and are arranged so that the urging direction of the holding member 50 is switched depending on the position of the attachment pin 57.

  Reference numeral 58 denotes a guide member that extends along the shaft 30 a of the feeding roller 30. The guide member 58 is integrally formed with the holding member 50. When the holding member 50 is in the holding position, that is, when the feeding roller 30 is in the standby position, the document set on the paper feed tray 20 is set at the downstream setting position. To guide. In particular, the document whose tip is deformed to the upper side is prevented from coming into contact with the feeding roller 30 and its peripheral parts, thereby preventing document conveyance failure.

  Next, the holding / releasing operation of the holding means will be described with reference to FIGS. The holding member 50 moves from the holding position to the retracted position when the feeding roller 30 moves from the standby position to the feeding position, and moves from the retracted position to the holding position when the feeding roller 30 moves from the feeding position to the standby position. It is configured.

  First, the movement of the holding member 50 from the holding position to the retracted position will be described. When the feeding roller 30 is in the standby position, the holding member 50 is rotated counterclockwise by the biasing spring 60 as shown in FIG. The outer side surface 53 abuts on the protrusion 73 of the paper feed cover 70 and stops. The shaft 30a of the feeding roller 30 is in contact with the inner side surface 55 (first contact surface) of the first portion 51 of the L-shaped holding member 50, and the lowering of the feed roller 30 is prevented.

  When the drive motor MT is driven to rotate forward from the state shown in FIG. 7A, the support holder 40 rotates downward about the shaft 31 a of the paper feed roller 31. As a result, the feeding roller 30 is lowered, and the shaft 30 a of the feeding roller 30 pushes down the first portion 51 of the L-shaped holding member 50 against the biasing force of the biasing spring 60. The holding member 30 rotates in the clockwise direction by the pressing operation by the feeding roller 30. Then, as shown in FIG. 7B, the position of the mounting pin 57 of the holding member 50 is below the straight line X connecting the mounting point A to which one end of the biasing spring 60 is mounted and the rotation fulcrum B of the holding member 50. The biasing spring 60 acts to rotate the holding member 50 in the clockwise direction. The holding member 50 rotates in the clockwise direction by the action of the biasing spring 60, and the holding member 50 stops when the regulating piece 59 of the holding member 50 contacts the protrusion 73 of the paper feed cover 70. That is, the holding member 50 is rotated by the lowering of the feeding roller 50 up to the position of the straight line X in the drawing, and is rotated by the action of the biasing spring 60 from the position of the straight line X.

  On the other hand, the feeding roller 30 is lowered by the forward rotation drive of the drive motor MT, and comes into contact with the upper surface of the original on the paper feed tray 20 as shown in FIG.

  Next, the movement of the holding member 50 from the retracted position to the holding position will be described. When the feeding roller 30 is in the feeding position, the holding member 50 is rotated clockwise by the biasing spring 60 as shown in FIG. The restricting piece 59 is abutted against the protrusion 73 of the paper feed cover 70 and stopped at the retracted position. At this time, the feeding roller 30 contacts the upper surface of the document or the placement surface of the paper feed tray 20, and the first portion 51 of the holding member 50 is in a position retracted from the raising / lowering locus of the feeding roller 30.

  When the drive motor MT is driven in reverse from the state shown in FIG. 8A, the support holder 40 rotates upward with the shaft 31a of the paper feed roller 31 as a fulcrum. As a result, the feeding roller 30 rises and the shaft 31 a of the paper feed roller 31 comes into contact with the inner side surface 54 (second contact portion) of the second portion 52 of the holding member 50. Then, the shaft 30 a of the feeding roller 30 pushes up the second portion 52 of the L-shaped holding member 50 against the biasing force of the biasing spring 60. The holding member 30 rotates counterclockwise by the pushing-up operation of the feeding roller 30. When the position of the mounting pin 57 of the holding member 50 moves upward beyond the straight line X as shown in FIG. 8B, the biasing spring 60 acts to rotate the holding member 50 in the clockwise direction. To do. The holding member 50 rotates counterclockwise by the action of the biasing spring 60, and stops at the holding position when the outer surface 53 of the second portion 52 of the holding member 50 comes into contact with the protrusion 73 of the paper feed cover 70. To do. At this time, as shown in FIG. 6, the portion of the support holder 40 that supports the feeding roller 30 comes into contact with an elastic member 75 such as rubber attached to the inside of the paper feed cover 70 and stops. The inner surface 55 of the portion 51 moves to a position that prevents the feeding roller 30 from being lowered by its own weight. Therefore, even if the electromagnetic clutch is turned off in the state shown in FIG. 7A, the shaft 30a of the feeding roller 30 abuts against the inner surface 55 of the first portion 51 of the holding member 50, and the lowering of the feeding roller 30 is prevented. The Further, even if the driving unit is disconnected by the opening operation of the paper feed cover 70, the feeding roller 30 can be held at the standby position.

  In the above embodiment, the shaft 30a of the feeding roller 30 is in contact with the inner side surface 55 of the first portion 51 and the inner side surface 54 of the second portion 52 of the holding member 50. As shown in FIG. 4, the operating piece 80 is protruded from one side of the support holder 40 (side of the extending direction of the shaft 30 a of the feeding roller 30), and the operating piece 80 is inserted into the first portion 51 of the holding member 50. The side surface 55 and the inner side surface 54 of the second portion 52 may be in contact with each other, and the holding means 50 may be held and released.

  In the above embodiment, an example in which the paper feeding device of the present invention is applied to an original conveying device has been described. However, the paper feeding device of the present invention is applied to a paper feeding unit of an image forming apparatus such as a printer or a copying machine. Of course, it may be.

  According to the above embodiment, the movement of the holding member 50 from the holding position to the retracted position is moved by the lowering of the feeding roller 50 to the position of the straight line X in the drawing, and the biasing spring is moved from the position of the straight line X. It is moved by the action of 60. On the other hand, the movement of the holding member 50 from the retracted position to the holding position is moved by the raising of the feeding roller 50 to the position of the straight line X, and is moved from the position of the straight line X by the action of the biasing spring 60.

  With such a configuration, even when the drive mechanism is disconnected, the feeding roller is reliably held at the standby position with a simple configuration, and the document can be easily set on the paper feed tray. Can do.

  In order to hold the feeding roller at the standby position, it is also conceivable to form a curved portion with a "<" shape at the tip of a plate spring made of resin or metal, and to fit and hold the feeding roller in this curved portion. . However, if a leaf spring is used, the holding force is impaired due to deformation over time or attachment errors, and the feeding roller may fall. On the other hand, according to the holding means in the present embodiment, the feeding roller can be reliably held at the standby position.

DESCRIPTION OF SYMBOLS 1 Reading apparatus main body 10 Document conveying apparatus 20 Paper feed tray 30 Feeding roller 31 Paper feed roller 40 Support holder 50 Holding member 58 Guide 60 Biasing spring 70 Paper feed cover MT Drive motor ECL1 1st electromagnetic clutch

Claims (8)

A sheet feeding tray on which a sheet is placed, a feeding roller for feeding the sheet in contact with the sheet on the sheet feeding tray, a sheet feeding roller for separating and feeding the fed sheet into one sheet, and a separating member. In a sheet feeding apparatus comprising: a separating unit; and a lifting unit that moves up and down to a feeding position where the feeding roller is in contact with the sheet and a standby position separated from the sheet.
A holding position that holds the feeding roller at the standby position and a holding member that is movably provided at a retracted position that is retracted from the holding position;
The holding member, the move to rise thus the holding position of the feed roller, paper feeding apparatus, characterized in that to move down to the result the retracted position of the feed roller.
The sheet feeding device according to claim 1, wherein a rotation shaft that rotates the holding member is provided, and the holding member rotates between the holding position and the retracted position with the rotation shaft as a fulcrum. The supporting means for supporting the feeding roller is provided, and the supporting means abuts on the holding member by moving the feeding roller up and down to move the holding member. Paper feeder. The restriction member for restricting the movement of the holding member at the holding position, and the biasing member for biasing the holding member on the restriction member side are provided. Paper feeder. The said holding member is provided with the guide member which guides the upper surface of the sheet | seat mounted on the said paper feed tray in the said holding position to the downstream side. Paper feeder. The sheet feeding tray includes a sheet feeding tray, a feeding roller that feeds the sheet in contact with the sheet on the sheet feeding tray, a sheet feeding roller that separates the fed sheet into a single sheet, and a separating member. In a sheet feeding apparatus comprising: a separating unit; and a lifting unit that moves up and down to a feeding position where the feeding roller is in contact with the sheet and a standby position separated from the sheet.
A holding means for holding the feeding roller at the standby position;
The holding means is
A holding position for holding the feeding roller in a standby position, and a holding member provided movably in a retracted position retracted from the holding position;
When the position of the holding member is closer to the holding position than the predetermined position, the holding member is urged toward the holding position, and when the position of the holding member is closer to the retracted position than the predetermined position A biasing member disposed on the position side so as to bias the holding member,
The holding member moves from the holding position to the predetermined position when the shaft of the feeding roller or a part of the support holder that supports the feeding roller comes into contact with the lowering of the feeding roller, and the predetermined member is moved by the biasing member. The sheet feeding device moves from the position to the retracted position, moves from the retracted position to the predetermined position by the raising of the feeding roller, and moves from the predetermined position to the holding position by the biasing member. . A drive shaft that rotatably supports the holder member, a drive means for driving the drive shaft, and a clutch means for controlling transmission of the drive of the drive means to the drive shaft. The sheet feeding device according to claim 6. The holding member is formed into an L-shaped resin, and the L-shaped holding member is provided on a side surface of a central corner of the L-shaped holding member, and a rotation shaft for rotating the holding member. A first abutting portion provided on an inner surface side of the L-shaped holding member and a portion of the feeding roller shaft or a part of the support holder abuts when the feeding roller descends; And a second abutting portion that is provided on an inner surface side of the holding member and that abuts on a shaft of the feeding roller or a part of the support holder when the feeding roller ascends. The sheet feeding device according to claim 6 or 7.

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