JP2007099422A - Sheet material feeder, image forming device and image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material feeder capable of stabilizing separation of the sheet material, preventing double-feeding of the sheet material and shortening an action time relating to prevention of double-feeding without requiring complicated control by a simple and small sized constitution. <P>SOLUTION: The sheet material feeder is provided with a returning lever 13 for returning the sheet materials on or after second sheets intruding to a separation part to a loading part; and a separation roller holder 26 contactably/leavably retaining a separation roller 12 relative to a feeding roller 11. Further, a restriction part 26b for restricting the number of sheets of the sheet material intruding between the feeding roller and it in an upstream side in a conveying direction of the separation part is integrally provided on the separation roller holder. When the separation roller is left, the sheet materials on and after the second sheet intruding to the separation part are returned to the loading part by the returning lever. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet material feeding apparatus, an image forming apparatus, and an image reading apparatus for feeding a sheet material such as a recording material, a copying material, or a document one by one.

  Sheet material feeding apparatuses are widely used in image forming apparatuses (or recording apparatuses) such as printers, copiers, printing apparatuses, facsimile machines or scanners, image reading apparatuses, and the like. In these devices, the sheet material feeding device separates and feeds a sheet material (for example, a sheet) such as a recording material, a copying material, or a document one by one to an image recording unit, a copying unit, or a reading unit. is there.

  This type of sheet material feeding device separates and feeds sheet materials one by one to a predetermined position, so that a double feed prevention mechanism for preventing two or more sheet materials from being fed simultaneously at the same time It has. As a sheet material feeding device provided with a double feed prevention mechanism, a retard roller method, a return lever method, or a combination of both methods is known. The retard roller system is a system that uses a roller that is forcibly rotated in the direction opposite to the conveying direction of the sheet material via a torque limiter. The return lever method is a method in which the return lever is operated every time a predetermined number of sheet materials are conveyed to return the sheet material remaining in the feeding unit to a predetermined position of the stacking unit.

  For example, Patent Document 1 discloses a return lever type sheet material feeding device. This is because the feed roller is rotated in the forward direction by the drive source of the sheet feeding device to perform the feeding operation, and after the feeding roller is rotated once and the feeding operation is completed, the drive source is rotated in the reverse direction. By moving the return lever, the leading end of the sheet material is returned to a predetermined position. Further, a combined system in which a retard roller and a return lever are combined is disclosed in Patent Document 2, for example. The retard roller of Patent Document 2 is forcibly driven to rotate in the direction opposite to the sheet material conveying direction via a feeding roller and a torque limiter. In Patent Document 2, the retard roller is separated in conjunction with the operation of separating the stacked sheet material from the feeding roller, and the return lever is operated almost simultaneously with the separation to operate the second and subsequent sheet materials. The tip is configured to return to a predetermined position.

In addition to the double feed prevention mechanism, as a means for further improving the separation margin, for example, Patent Document 3 proposes a configuration that regulates the number of sheets that enter the separation portion. This is to regulate the number of sheets that enter the sheet material by forming irregularities in the gap in the axial direction of the feed roller in a separation pad type feeding device, which is one of the friction separation methods. In this case, the concavo-convex gap is formed by a protrusion provided on the upstream side of the separation pad and a protrusion formed by protruding a part of the sheet cassette toward the feed roller.
JP-A-10-181904 JP-A-10-167502 JP-A-8-2721

  However, the conventional sheet feeding device has the following technical problems in terms of the configuration and operation of the double feed prevention mechanism. In other words, in a sheet material feeding device using a retard roller, a torque limiter that maintains an appropriate release torque is provided, and the roller needs to be reversed during the feeding operation, which complicates the mechanism and increases the size of the device. Or, the cost was increased. Further, in the friction separation method using a retard roller or a separation pad, when a plurality of coated papers or OHPs having a high friction coefficient enter between the separation member and the feeding roller, there is a tendency that double feeding tends to occur. Furthermore, since the return lever is operated after a series of feeding operations is completed, it is necessary to provide time for the return lever operation separately from the feeding operation, and the operation time for preventing double feeding becomes longer. There was a trend. Furthermore, since there is a protrusion in the vicinity of the sheet material conveyance path, a scratch is generated due to rubbing between the protrusion and the sheet material when the separated sheet material is conveyed, and a friction load (back tension) is generated. There was also a problem.

  The present invention has been made in view of such technical problems. The object of the present invention is to stabilize the separation of the sheet material with a simple and small configuration and to prevent the sheet material from being double fed, and to reduce the operation time related to the prevention of double feeding without requiring complicated control. It is providing the sheet material feeding apparatus which can do.

  The present invention provides a feeding roller that feeds a sheet material, a stacking unit that holds the sheet material so as to be able to come into contact with and away from the feeding roller, and is urged by the feeding roller during feeding. The present invention relates to a sheet material feeding device including a separating unit for separating sheet materials one by one. The sheet material feeding apparatus according to the present invention includes a return means for returning the second and subsequent sheet materials that have entered between the feeding roller and the separating means to the stacking unit, and the separating means for feeding the sheet. And a separating means holding member for holding the roller so as to be able to contact and separate. In the present invention, a gap that regulates the number of sheets that enter the separation unit is formed between the separation roller and the feeding roller at a position upstream of the separation unit in the conveyance direction, integrally with the separation unit holding member. A restricting section is provided for this purpose. Therefore, in the present invention, when the separating means is separated via the separating means holding member, the second and subsequent sheet materials that have entered between the feeding roller and the restricting portion are moved by the return means. It is configured to return to the loading section.

  According to the present invention, the separation of the sheet material can be stabilized with a simple and small configuration and the sheet material can be prevented from being double-fed, and the operation time relating to the prevention of double-feed can be reduced without requiring complicated control. There is provided a sheet material feeding apparatus capable of performing the above.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 11 is a cross-sectional view showing an image forming apparatus and an image reading apparatus having a sheet material feeding apparatus to which the present invention is applied. FIG. 11 exemplifies the case of an image reading and recording apparatus in which the image forming apparatus and the image reading apparatus are integrated, but the present invention is naturally applicable to a single image forming apparatus or an image reading apparatus as well. Is. The image reading and recording apparatus of FIG. 11 is configured by integrating an image forming apparatus 50 that records an image on a sheet material with a recording unit based on recording information and an image reading apparatus 70 that reads an original with a reading unit.

  In FIG. 11, an image forming apparatus 50 supports and supports a carriage 53 that can reciprocate in the width direction of the sheet material along a guide shaft 51 and a guide rail 52, and the carriage 53 is a recording head that is a recording unit. 54 is mounted. The illustrated image forming apparatus 50 is an ink jet recording method, and is configured to form an image by ejecting ink from the ejection ports of the recording head 54 based on image information. A platen 59 for supporting the recording sheet P is disposed at a position facing the recording head 54. Conveying means including a conveying roller 55 and a pinch roller 56 is disposed on the upstream side of the recording head 54 in the conveying direction, and discharging means including a discharge roller 57 and a spur 58 are disposed on the downstream side in the conveying direction. . The image forming apparatus 50 as a main body is provided with a sheet material feeding device 100 for separating and feeding the uppermost sheet material P such as a stacked recording sheet to the conveying means 55 and 56. ing. The sheet material P recorded while being conveyed by the conveying means 55 and 56 is discharged out of the main body by the paper discharging means 57 and 58.

  In FIG. 11, an image reading device 70 is configured to read a sheet material (original) P conveyed between a contact image sensor 61 for reading an image and a white plate 62 as a white reference. The contact image sensor 61 constitutes reading means for reading a document. A conveying means consisting of a conveying roller 65 and a pinch roller 66 is arranged upstream of the reading means 61 in the conveying direction, and a discharging means consisting of a discharging roller 67 and a spur 68 is arranged downstream of the reading means in the conveying direction. It is installed. The image reading device 70 is also provided with a sheet material feeding device 100 for separating the uppermost sheet material P such as a stacked document and feeding it to the conveying means 65 and 66. The document (sheet material) P whose image has been read while being conveyed between the contact image sensor 61 and the white plate 62 by the conveying means 65 and 66 is discharged out of the main body by the discharging means 67 and 68. The sheet material feeding device according to the present invention is a sheet material such as a recording sheet or a document, such as the sheet material feeding device of the image forming apparatus 50 as described above and the sheet material feeding device of the image reading device 70 as described above. The present invention can be widely applied to a device for separating and feeding.

  Generally, a sheet material feeding device is designed on the assumption that it is used in an integrated manner with an image forming apparatus (or recording apparatus) such as a printer, a copying machine, a printing apparatus, a facsimile machine or a scanner, or an image reading apparatus. . The sheet material feeding apparatus according to the present embodiment does not include a drive source, and is driven by a driving force transmitted from an image forming apparatus or an image reading apparatus (hereinafter abbreviated as a main body). As a matter of course, a configuration in which a drive source is provided in the sheet material feeder itself may be used. Further, the image forming apparatus includes a recording apparatus that forms (records) an image on a sheet material that is a recording medium by a recording unit based on image information, and the image is formed on the sheet material regardless of a latent image or a visible image. Refers to all devices to be formed. Here, the image includes characters and symbols. The image reading apparatus is an apparatus that reads a document by reading means. Furthermore, the image forming apparatus is not limited to an ink jet type (ink jet recording apparatus) that records ink by ejecting ink from a recording head, as well as any recording method such as a thermal transfer type, a laser beam type, a thermal type, and a wire dot type. It may be a thing.

  FIG. 1 is a perspective view of an embodiment of a sheet feeding apparatus according to the present invention. FIG. 2 is a front view of the sheet material feeding apparatus of FIG. FIG. 3 is a side view showing the drive mechanism of the sheet material feeding apparatus according to the present embodiment as seen from line 3-3 in FIG. FIG. 4 is a cross-sectional side view in which the sheet material feeding device according to the present embodiment is sectioned along the line 4-4 in FIG. 1 to 4, a sheet material feeding apparatus 100 according to the present embodiment is a rotating body for feeding a sheet material (for example, a sheet) P such as a recording material, a copying material, or a document to a conveyance unit. A feed roller 11 is provided. The feed roller 11 is rotatably supported by a feed shaft 10 on a base portion 15 made of a frame or the like.

  The sheet material feeding apparatus 100 includes a separation unit including a separation roller 12 having a torque limiter 12a related to separation of the sheet material P, a return unit including a return lever 13 related to prevention of sheet material double feeding, and the return lever. And a return lever control cam 14 to be driven. Further, the sheet material feeding device includes a pressure plate 16 that stacks a plurality of sheet materials and is biased toward the feeding roller 11. A side guide 17 for restricting the position in a direction orthogonal to the sheet material conveyance direction is movably mounted on the pressure plate 16 constituting the sheet material stacking unit. A feeding roller 18 is provided on the side of the feeding roller 11 to prevent the sheet material released from the feeding roller from coming into contact with the feeding roller.

  The sheet material feeding apparatus includes a sheet material stacking unit, a feeding / separating unit, and a multifeed preventing unit, which will be described separately below. In the present embodiment, the sheet material stacking portion is formed of a pressure plate 16 that supports the front half of the sheet material and a base portion 15 that supports the rear half. The sheet material stacking portion is formed of a sheet material placement surface that is inclined at an angle of about 30 to 90 degrees with respect to a horizontal plane. The sheet material stacking unit is provided with a conveyance reference unit 15 a formed integrally with the base unit 15. This conveyance reference portion serves as a positioning reference in a direction orthogonal to the conveyance direction of the sheet material stacked on the pressure plate 16. The opposite side portion of the sheet material stacked on the pressure plate is positioned by a side guide 17 mounted on the pressure plate so as to be movable (slidable). In a standby state in which the sheet material feeding device is not performing a conveying operation, the pressure plate 16 is held at a separated position away from the feeding roller 11, and a plurality of sheets are interposed between the feeding roller 11 and the pressure plate 16. Sufficient clearance is secured to load the material.

  The sheet material feeding apparatus 100 is designed to be adapted to a sheet material of an arbitrary size within a predetermined range. First, a plurality of sheet materials are inserted between the feeding roller 11 and the pressure plate 16, and a bundle of the sheet materials is stacked on the pressure plate in a state along the conveyance reference portion 15a. Next, the side guide 17 is moved in the direction of arrow C in FIG. 1 to match the width of the sheet material (to be along the opposite side). As a result, the bundle of sheet materials set on the stacking unit (pressure plate 16) is restricted in position in the direction orthogonal to the conveyance direction, and is in a state where stable separation / feeding and conveyance are possible. The side guide 17 slidably attached to the pressure plate 16 can be engaged and fixed with a latch groove formed in the pressure plate 16 so as not to move carelessly. Therefore, when the side guide 17 is moved, the lever 17a provided on the side guide is operated to release the latch and move it.

The sheet material loaded on the pressure plate 16 descends downward due to the gravity, and the tip of the sheet material hits the tip reference portion 15 b provided on the base portion 15. The tip reference portion 15b is formed in a rib shape in order to reduce the load during feeding of the sheet material.
The pressure plate 16 can be rotated (swinged) about a fulcrum provided at the upper end thereof. The operation of the pressure plate is controlled by a spring and a cam. That is, the pressure plate is urged toward the feeding roller 11 by the pressure plate spring 19. The movement of the pressure plate in the direction away from the feed roller 11 is forced by the cam 22a provided on the feed shaft gear 22 fixed to one end of the feed shaft 10 pushing the pressure plate against the pressure plate spring. Done. Such an urging (pressing) / separating operation is performed at a predetermined timing as described later, whereby the sheet material feeding operation is performed.

  Next, the feeding / separating unit will be described. The pressure plate 16 spring-biased toward the feed roller 11 is operated at a predetermined timing according to the rotation of the feed roller 11 by a cam 22 a provided on the feed shaft gear 22. The bundle of sheet materials placed on the pressure plate stacking unit is pressed against the feeding roller by the operation of the pressure plate. The pressed sheet material is conveyed by frictional force by the rotation of the feeding roller 11 so that the uppermost sheet that contacts the feeding roller is used. Since the sheet material is separated, fed, and conveyed by frictional force, the material of the feeding roller 11 is rubber, urethane foam, or the like having a higher friction coefficient than the sheet material. In this embodiment, for example, rubber such as EPDM (ethylene / propylene / diene copolymer) having a hardness of about 20 to 40 degrees (A scale) is used.

  First, the driving mechanism of the feeding / separating unit will be described with reference to FIGS. 3 and 4. 3 and 4, the driving mechanism of the feeding / separating unit has an input gear 20, and the driving on the main body side of the image forming apparatus, the image reading apparatus, etc. is transmitted from this input gear to the sheet material feeding apparatus. . The drive mechanism of the feed / separation unit includes a double gear 21 that meshes with the input gear 20, a feed shaft gear 22 that is fixed to the feed shaft 10 while meshing with the double gear, and a control gear 23 that meshes with the feed shaft gear. I have. The drive mechanism further includes a return lever control cam 14 that controls the return lever 13. The control gear 23 controls the separation roller 12 having the torque limiter 12a.

  The relative positions of the return lever 13 and the return lever control cam 14 which are return means are urged in one direction by a return lever spring 24. Further, the separation roller 12 as a separation means is rotatably supported on a separation roller holder 26 as a separation means holding member. The separation roller holder 26 is urged by a spring 25 in a direction in which the separation roller is pressed against the feeding roller 11. The spring 25 functions as a separation roller pressing spring.

  The input gear 20 rotates in the direction of arrow B in FIG. 3 by the driving force transmitted from the main body side gear such as an image forming apparatus or an image reading apparatus. This driving force is transmitted to the feed shaft gear 22 while being decelerated via the double gear 21, and the feed shaft gear 22 rotates in the direction of arrow A in FIG. Further, this driving force is transmitted from the feed shaft gear 22 to the control gear 23. Here, the feed shaft gear 22 and the control gear 23 are connected at a reduction ratio of 1: 1, and always rotate at a synchronized angular phase. A cam 23 a is formed on one side of the control gear 23. The return lever control cam 14 is urged in one direction by a return lever spring 24 so that the cam follower portion 14b always follows the cam 23a of the control gear 23. Accordingly, the return lever control cam 14 is driven and controlled in synchronization with the feed shaft 10.

  Furthermore, a cam (not shown) is also provided on the surface opposite to the control gear 23, that is, the surface opposite to the cam 23a, and the separation roller control cam 27 (FIG. 4) is driven by this cam. The separation roller control cam controls the position of the separation roller 12 in synchronization with the rotational position of the feeding shaft 10. That is, as described above, the separation member made of the separation roller 12 is rotatably held by the separation member holding member made of the separation roller holder 26, and the separation roller holder 26 is also supported rotatably about the fulcrum 26a. Yes. Further, the separation roller 12 with the torque limiter 12 a is urged toward the feeding roller 11 by the action of the separation roller pressing spring 25. The separation roller control cam 27 performs drive control so that the separation roller 12 is separated from the feeding roller 11 by releasing this bias at a predetermined timing described later.

  Next, the configuration of the feeding / separating unit will be described. In FIG. 1 to FIG. 4, the uppermost sheet of a bundle of sheet materials stacked on the stacking unit including the pressure plate 16 and the like is conveyed by the feeding roller 11. Basically, the frictional force between the feeding roller 11 and the uppermost sheet material is often larger than the frictional force between the uppermost sheet material and the sheet material immediately below the uppermost sheet material. In many cases, only the sheet material is conveyed. However, a plurality of sheet materials may be pulled out at a time by the feeding roller 11. This is the case, for example, when there is an effect of burrs at the edges that can occur when cutting sheet materials, when there is sticking between sheet materials due to static electricity, or when using sheet materials with a very large surface friction coefficient. is there. In that case, in the present embodiment, only the uppermost sheet material is separated by the following method.

  The separation roller 12 is pressed so as to contact the feeding roller 11 at a position downstream of the feeding direction from the point where the feeding roller 11 and the sheet material P first contact each other. The separation roller is only held rotatably with respect to the separation roller holder 26, and is not actively driven to rotate. However, the separation roller is configured not to rotate below a predetermined torque by the torque limiter 12a. That is, a predetermined torque needs to be maintained in order to rotate the separation roller 12.

  10A and 10B are diagrams illustrating the configuration of the separation roller 12 with the torque limiter 12a, wherein FIG. 10A is a longitudinal sectional view of the center portion, and FIG. 10B is an end view as viewed from line bb in FIG. It is. 10 (a) and 10 (b), the support shaft 12-1 of the torque limiter 12a is fixed to the separation roller holder 26, and is made of metal or plastic between the support shaft 12-1 and the torque limiter 12a. The coil spring 12-2 is housed. In a normal state (initial state), the inner diameter portion of the coil spring 12-2 fastens the surface of the support shaft 12-1. Torque (friction torque, etc.) in the direction of the arrow in (b) acts on the separation roller 12, the separation roller rotates to a predetermined angle against the coil spring 12-2, and the inner diameter of the coil spring 12-2 expands. Then, the coil spring and the support shaft slide relatively with respect to the support shaft 12-1. Thus, a predetermined torque needs to be maintained in order to rotate the separation roller 12.

  The separation roller 12 has a high friction coefficient such as EPDM (ethylene / propylene / diene copolymer) having a hardness of about 20 to 40 degrees (A scale) so as to have a friction coefficient equivalent to that of the feeding roller 11. It is made of rubber or urethane foam. With such a configuration, when there is no sheet material between the feeding roller 11 and the separation roller 12 with the torque limiter 12a, the separation roller 12 is rotated in accordance with the rotation of the feeding roller 11. Further, when one sheet material enters between the feeding roller 11 and the separation roller 12, the frictional force between the feeding roller 11 and the sheet material is larger than the torque value of the torque limiter 12a. Therefore, the sheet material is conveyed while the separation roller 12 is driven to rotate.

  FIG. 5 is a partial side view showing a state when a plurality of sheet materials are about to enter between the feeding roller and the separation roller in the sheet material feeding apparatus according to the present embodiment. FIG. 6 is a perspective view of the feeding roller portion of the sheet material feeding apparatus according to the embodiment as seen obliquely from above. FIG. 7 is a side sectional view showing the configuration and operation of the main part of the sheet material feeding apparatus according to this embodiment. In the present embodiment, the separating roller holder 26 is integrally provided with a restricting portion 26b for restricting the number of sheets P entering the separating portion. The restricting portion 26b restricts entry of the sheet material into the separating portion by setting the sheet material conveying gap formed between the feeding roller 11 to a predetermined amount (gap m in FIG. 5). (Suppress).

  The number of sheets entering when a plurality of sheet materials are about to enter between the feeding roller and the separation roller is regulated by a regulation portion 26 b provided integrally with the separation roller holder 26. Therefore, for example, as shown in FIG. 5, when two or more sheet materials enter between the feeding roller 11 and the separation roller 12, slippage occurs between the sheet materials. That is, the frictional force between the feeding roller and the sheet material on the feeding roller side is larger than the frictional force between the sheet material and the sheet material, and the rotation start torque of the torque limiter 12a is between the sheet material and the sheet material. Therefore, slippage occurs between the sheet material and the sheet material. As a result, one sheet material on the feeding roller 11 side is conveyed, and the other sheet materials are not conveyed.

  Next, the double feed prevention unit of the sheet material feeding device according to the present embodiment will be described. As described above, even when two or more sheet materials enter the nip portion (contact portion) between the feeding roller 11 and the separation roller 12, it is possible to separate the uppermost sheet. However, when, for example, static electricity is generated between the sheet materials and the adhesion is increased, there is a possibility that multiple feeds in which a plurality of sheet materials are simultaneously conveyed may occur. In this multi-sheet feeding, after a plurality of sheet materials are contained and only the sheet material on the feeding roller side is conveyed, the next sheet material is continuously fed while leaving the sheet material near the nip portion. May also occur. In order to prevent such double feed, a double feed prevention unit is provided.

  The double feed prevention unit in this embodiment includes the return lever control cam 14 and the return lever 13 in the drive mechanism of the feeding / separating unit described above. In FIG. 3, the return lever control cam 14 is provided at one end of the return lever 13 having a structure extending in a direction intersecting with the conveying direction of the sheet material feeding apparatus. In this case, the return lever control cam 14 is provided so as to be rotatable integrally with the return lever 13. Therefore, the return lever 13 can be rotated in the sheet material return direction by rotating the return lever control cam 14 in the direction of arrow C in FIG. Further, the return lever 13 and the return lever control cam 14 operate in synchronization with the rotation of the control gear 23 as described in the drive mechanism of the feeding / separating unit.

  FIG. 8 is a partial side cross-sectional view illustrating the operation of the sheet material feeding device according to the present embodiment in order of (a), (b), (c) and (d). Hereinafter, the operation of the return lever 13 when the sheet material is fed will be described with reference to FIGS. 3, 7, and 8. As shown in FIG. 4, the feeding roller 11 has a D shape when viewed from the axial direction of the feeding shaft 10, that is, a shape obtained by cutting a part of the outer peripheral surface of the cylindrical body into a flat surface. Accordingly, during the rotation of the feeding roller 11 once, the cut surface 11a of the feeding roller 11 is brought into contact with the separation roller 12 after the leading end of the fed sheet material is nipped by the main body side (conveying roller pair or the like). By facing each other, a gap is formed between these rollers. That is, the second half of the sheet material passes between the feeding roller and the separation roller in a state where the roller surface of the feeding roller 11 does not contact the sheet material.

  At this time, since the sheet material conveyance path in the separation portion is bent in a dogleg shape, the sheet material P tends to be wound around the roller surface of the feeding roller 11 by its rigidity. Therefore, if nothing is done, the sheet material comes into contact with the roller surface of the feeding roller 11 having a large friction coefficient, and a large friction load (back tension) is exerted on the conveying force of the conveying means on the main body (not shown). Will occur. In order to prevent this frictional load, a feeding roller 18 as shown in FIGS. 1 and 2 is provided in the vicinity of the feeding roller 11 of the feeding shaft 10. The feeding roller is formed of a rotating body that has a low coefficient of friction and is easily driven. Thus, after the sheet material being fed is gripped on the main body side, the sheet material is conveyed along a conveyance path in contact with the feeding roller 11 as indicated by an imaginary line X in FIG. Become.

  Next, the operation of the return lever 13 synchronized with one rotation of the feeding roller 11 will be described with reference to FIG. 8 showing the drive timing of the return lever 13 which is a return means. FIG. 8A shows a standby state of sheet material feeding. When feeding is started from this standby state, the control gear 23 starts to rotate in the direction of arrow D in synchronization with the rotation of the feeding shaft 10 of the feeding roller. As the control gear rotates in the direction of arrow D, the cam follower portion 14b of the return lever control cam 14 disengages the cam 23a of the control gear 23. As a result, the return lever 13 integrated with the return lever control cam 14 rotates in the sheet material conveying direction (in the direction of arrow E in FIG. 8B) by the urging force of the return lever spring 24, and (c) in FIG. ) As shown in FIG. 7.

  At this time, the protrusion 14a of the return lever control cam 14 comes into contact with the flange portion 23b of the control gear 23, whereby the rotation of the return lever control cam 14 is stopped and the retracted position of the return lever 13 is determined. When the return lever 13 is completely retracted from the sheet material conveyance path X, the fixing of the pressure plate 16 (fixing to the separation position) by the cam 22a of the feeding shaft gear 22 is released, and the pressure plate 16 is fed by the pressure plate spring 19 to the feeding roller 11. Biased in the direction. As a result, the bundle of sheet materials stacked on the pressure plate is pressed against the feeding roller, and the uppermost sheet material is brought into pressure contact with the feeding roller 11. When the sheet material is pressed against the feeding roller, feeding of the sheet material is started.

  Then, when one sheet material separated and fed by the feeding roller 11 is held or gripped by the conveying means on the main body side, and the cooperative conveyance by the feeding roller 11 and the conveying means is started, The operation enters the double feed prevention operation. The pressure plate 16 is pushed (moved) in a direction away from the feeding roller 11 by the cam 22a of the feeding shaft gear 22. When the pressure plate 16 is separated, the pressure contact of the uppermost sheet material to the feeding roller 11 is released, so that the conveying force of the sheet material decreases. Immediately after this, the cut surface 11 a of the D-shaped feeding roller 11 starts to face the pressure plate 16. However, the separation roller 12 and the feed roller 11 are still in pressure contact, and the separated sheet material continues to be conveyed.

  When the conveyance rotation of the feeding roller 11 continues further from the state of FIG. 8C and the control gear 23 rotates in the direction of arrow D to the position shown in FIG. 8D, the cam 23a of the control gear 23 is returned to the return lever control cam 14. Again comes into contact with the cam follower portion 14b. As a result, the return lever 13 is rotated together with the control cam 14 in the direction of arrow F in FIG. 8D (the direction opposite to the transport direction) against the return lever spring 24. When the return lever 13 starts to rotate in the direction of arrow F, the separation roller control cam 27 (FIG. 7) is driven by a cam (not shown) provided on the surface of the control gear 23 opposite to the cam 23a.

  The separation roller control cam 27 thus driven causes the separation roller holder 26 to rotate clockwise in FIG. 7 about the fulcrum 26a (FIG. 7) against the separation roller pressing spring 25 (FIG. 7). It is done. By the rotation of the separation roller holder, the separation roller 12 on the separation roller holder 26 moves in a direction away from the feeding roller 11. As a result, the pressure contact force of the separation roller 12 to the feeding roller 11 disappears, and the sheet material holding force (sheet material conveying force) in the sheet material feeding device is lost. However, at this time, the sheet material P is held so as to be conveyed by the conveying means (conveying roller or the like) on the main body side as described above. Each portion such as the return lever 13 and the separation roller holder 26 is configured to move from a position indicated by a solid line in FIG. 7 to a position indicated by a broken line at a predetermined timing.

  Further, in accordance with the timing when the sheet material holding force in the sheet material feeding device is lost, as will be described later, the front end portion 13a of the return lever 13 starts to enter the sheet material conveyance path X in the separation unit. As a result, except for the uppermost sheet material, the leading edge of the next sheet material or a plurality of sheet materials that has entered the separating portion is returned to the position of the leading edge reference 15b of the stacking portion. That is, the sheet material other than the uppermost sheet that has entered the separation unit is returned to the original position of the stacking unit by the return lever 13. The movement locus of the tip 13a of the return lever at this time is shown by a line 13c in FIG. Then, when the control gear 23 and the cam 23a are rotated by a predetermined amount from the position of FIG. 8 (d), the return lever control cam 14 is rotated by a predetermined amount in the counterclockwise direction shown in FIG. ). By the operation of the return lever 13 as described above, it is possible to prevent the second-order (second and subsequent) sheet material from being lowered (or taken out) accompanying the feeding of the uppermost sheet material.

  FIG. 9 is a partial side view showing operations of separation / feeding and prevention of double feeding of the sheet material feeding apparatus according to the present embodiment. In this embodiment, as shown in FIGS. 4, 5, 7, and 9, the separation roller holder 26 regulates the number of sheets that enter the separation portion while the separation roller 12 is in pressure contact with the separation roller holder 26. A restricting portion 26b (for example, restricting to 2 to 3 sheets or less) is integrally provided. The restricting portion 26b is disposed so as to form a conveyance path with a predetermined gap m (FIG. 5) at a position upstream of the nip portion between the feeding roller 11 and the separation roller 12 in the conveyance direction. As described above, when the return lever 13 starts to rotate in the direction of arrow F (the sheet material return direction) as shown in FIG. 8D, a cam (not shown) provided in the control gear 23 is used. The separation roller control cam 27 is driven.

  The separation roller holder 26 is rotated by the action of the separation roller control cam 27, so that the separation roller 12 is separated from the feeding roller 11. That is, as shown in FIG. 9, with the separation operation of the separation roller holder 26 from the feeding roller 11, the restricting portion 26b moves from the solid line to the broken line in FIG. 9 and retracts from the sheet material conveyance path. As shown in FIG. 6, the restricting portion 26 b in the present embodiment has a shape structure that extends in the roller axial direction so that the vicinity of the roller surface of the feeding roller 11 substantially straddles the length in the feeding roller axial direction. .

  With such a configuration, as shown in FIG. 9, the second lever (second sheet) is formed between the sheet material contact surface 13b of the return lever 13 and the top surface 26c from the top end portion 26d of the restricting portion 26b to the separation nip portion. Thereafter, an increase in driving load during conveyance can be prevented. At the same time, generation of a friction load (back tension) with the sheet material at the top end portion 26d of the restricting portion can be prevented. Further, the feeding roller 11 is rotated once and stopped while the leading end of the fed sheet material is held by the conveying means on the main body side. At this time, since the gap is formed by the cut surface 11a of the feeding roller 11 facing the separation roller 12, the image forming (recording) operation or image on the main body side is stopped after the feeding roller is stopped. During the conveyance accompanying the reading operation, the latter half of the sheet material passes through this gap.

  In the above-described embodiment, the configuration in which the sheets are separated and fed one by one from the top of the plurality of sheet materials stacked on the upper surface of the base portion 15 has been described as an example. The same can be applied to a configuration in which separation / feeding is performed from the bottom of the stack of stacked sheets. In other words, the present invention is similarly applied regardless of the uppermost or lowermost sheet material as long as it is the first-stage sheet material that enters the separating portion regardless of the uppermost or lowermost sheet material. be able to. Moreover, although the case where the D-cut-shaped feeding roller 11 is used has been illustrated in the above-described embodiment, the present invention is widely applied regardless of the shape structure of the feeding roller, such as when a round-shaped feeding roller is used. It is possible.

  In the embodiment described above, the separation roller with a torque limiter that does not have a drive source is provided so as to be able to contact the feeding roller, and by rotating the feeding roller, the uppermost one of the stacked sheet materials is fed to the feeding roller. And the separation roller. According to such a configuration, it is possible to easily prevent double feeding of the sheet material with a simple configuration without using a complicated separation mechanism such as a retard roller system and without causing an increase in size and cost of the apparatus. .

  In addition, a restricting portion facing the feeding roller is provided integrally with a holder that can move while holding the separation roller. According to this configuration, the separation operation can be stabilized by limiting the number of sheets that enter the separation portion of the sheet material. Further, by retracting the holder that holds the separation roller from the sheet material conveyance path during the sheet material feeding operation, the return lever can be operated while separating the separation roller. As a result, unnecessary interference between the sheet material and the restricting portion can be prevented, and an increase in driving load and generation of friction load (back tension) can be prevented. Furthermore, it is possible to shorten the feeding operation time related to prevention of double feeding without requiring complicated control.

  In the above-described embodiment, the case where the sheet material feeding device is used in the serial type image forming apparatus that records with the recording head mounted on the carriage has been described. The present invention can also be used in an image forming apparatus using a full line head or the like, and has the same effects. Further, in the above-described embodiment, the case where the image forming apparatus is an inkjet recording method has been described as an example. The sheet material feeding apparatus according to the present invention can be similarly applied to any recording type image forming apparatus such as a thermal transfer type, a thermal type, a laser beam irradiation type, and a wire dot type. The effect of this is achieved.

  The present invention can be applied in the same manner regardless of the structure and number of recording means (recording heads) and can achieve the same effect. Furthermore, the image forming apparatus and the image reading apparatus according to the present invention can be widely applied not only to a single apparatus but also to complex devices and systems. That is, the present invention can be widely applied to apparatuses and systems that handle sheet materials, such as composite apparatuses that combine copiers, facsimiles, captured image forming apparatuses, and the like, and input / output devices of composite apparatuses such as computer systems. The same effect is obtained.

It is a perspective view of one embodiment of a sheet material feeding device by the present invention. It is a front view of the sheet material feeding apparatus of FIG. It is a side view which shows the drive mechanism of the sheet material feeding apparatus which concerns on this embodiment seeing from the line 3-3 in FIG. FIG. 4 is a cross-sectional side view of the sheet material feeding device according to the present embodiment taken along a line 4-4 in FIG. 2 at a feeding roller portion. It is a partial side view showing a state when a plurality of sheet materials are about to enter between a feeding roller and a separation roller in the sheet material feeding device according to the present embodiment. It is the perspective view which looked at the part of the feed roller of the sheet material feeding apparatus which concerns on this embodiment from diagonally upward. It is side surface sectional drawing which shows the structure and operation | movement of the principal part of the sheet material feeding apparatus which concern on this embodiment. It is a partial side sectional view which shows operation of a sheet material feeding device concerning this embodiment in order with (a), (b), (c), and (d). It is a partial side view which shows the operation | movement of separation / feeding and the double feed prevention of the sheet material feeding apparatus which concerns on this embodiment. It is a figure which illustrates the composition of the separation roller with a torque limiter used by this embodiment, (a) is a central section longitudinal section, and (b) was seen from line bb in (a). It is an end view. 1 is a cross-sectional view illustrating a configuration example of a recording apparatus and an image reading apparatus that include a sheet material feeding apparatus to which the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Feed shaft 11 Feed roller 11a Cut surface 12 Separation means (separation roller)
12a Torque limiter 12-1 Support shaft 12-2 Coil spring 13 Return means (return lever)
13a Return lever tip 13b Sheet material contact surface 13c Movement trajectory of tip 13a 14 Return lever control cam 15 Base portion (stacking portion)
15a conveyance reference part 15b tip reference part 16 pressure plate (stacking part)
17 Side guide 18 Feed roller 19 Pressure plate spring 20 Input gear 22 Feed shaft gear 22a Cam 23 Control gear 23a Cam 24 Return lever spring 25 Spring (separating roller pressing spring)
26 Separation means holding member (separation roller holder)
26a fulcrum (center of rotation)
26b restricting portion 26c top surface 26d of restricting portion 26b top end portion of restricting portion 26b 27 separation roller control cam 50 image forming apparatus 54 recording means (recording head)
61 Reading means (contact image sensor)
62 White plate 70 Image reading device 100 Sheet material feeding device P Sheet material

Claims (7)

A feeding roller that feeds the sheet material, a stacking unit that holds the sheet material so as to be able to contact and separate from the feeding roller, and a sheet material at the time of feeding by being urged by the feeding roller. In a sheet material feeding device provided with separation means for separating sheets one by one,
A return means for returning the second and subsequent sheets that have entered between the feeding roller and the separating means to the stacking section, and the separating means are held so as to be able to contact and separate from the feeding roller. A separating means holding member,
Restriction for forming a gap for restricting the number of sheets that enter the separation portion between the feeding roller and the feeding roller at a position upstream of the separating means at the time of feeding integrally with the separating means holding member. Set up a section,
When the separating means is separated via the separating means holding member, the second and subsequent sheets that have entered between the feeding roller and the restricting portion are returned to the stacking portion by the returning means. Characteristic sheet material feeding device.   The sheet material feeding device according to claim 1, wherein the separation unit is separated from the feeding roller after the stacking unit is separated from the feeding roller.   The sheet material feeding device according to claim 1, wherein the stacking portion is inclined at an angle of about 30 to 90 degrees with respect to a horizontal plane.   The sheet material feeding device according to any one of claims 1 to 3, wherein the separating means is a roller with a torque limiter that does not have a driving source.   An image forming apparatus for recording an image on a sheet material by a recording unit based on recording information, comprising the sheet material feeding device according to claim 1.   The image forming apparatus according to claim 5, wherein the recording unit is an inkjet recording unit that discharges and records ink from an ejection port.   An image reading apparatus for reading a document by a reading unit, comprising the sheet material feeding device according to claim 1.

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