JP2013184818A - Medium supply device and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a chain of a skew state of a medium with a simple constitution.SOLUTION: A medium supply device 1 includes a feed roller 2 rotated by torque from a motor 8 transmitted to one feed shaft 21 and having two rollers 22a and 22b for carrying a medium S in the carrying direction, a brake roller 3 for making a predetermined carrying load act on the medium S of entering between the feed roller 2 and itself, by being brought into pressure contact with the feed roller 2, and a carrier roller 4 arranged on the downstream side in the carrying direction of the feed roller 2. One-way clutches 14a and 14b for allowing the roller to rotate in the carrying rotation direction for carrying the medium S in the carrying direction and regulating rotation in the reverse rotation direction of the carrying rotation direction, are individually arranged between the respective rollers 22a and 22b possessed by the feed roller 2 and the feed shaft 21. Peripheral velocity of the feed roller 2 can be controlled relatively slower than peripheral velocity of the carrier roller 4 by the motor 8.

Description

  The present invention relates to a medium supply device and an image reading device.

  In a medium supply device configured to separate and feed a medium sequentially from a plurality of stacked media, for example, the medium is skewed due to non-uniform pressure load between the rollers for feeding the medium or the influence of one piece. There is a case where a so-called skew occurs in a state of being sent in a posture. Once skew has occurred, the subsequent media is likely to be chained with skew.

  As a technique for correcting the skew, for example, Patent Document 1 includes a technique that includes two rollers in the transport width direction and independently drives and controls these rollers by two stepping motors, thereby correcting the skew of the medium. It is disclosed.

JP 2008-233330 A

  However, in the conventional skew correction method described in Patent Document 1, it is necessary to install a dedicated roller for skew correction or to independently control two rollers in the conveyance width direction by separate drive sources, which complicates the apparatus. There was a problem of increasing the size.

  In addition, in an image reading apparatus such as a scanner apparatus to which the medium supply apparatus is mainly applied or an inexpensive printer of consumer specification, the occurrence of a jam can be avoided, or if skew of the read image is inconspicuous, the skew is reduced. In many cases it is acceptable. In short, when skew occurs, even if the skew cannot be corrected with high accuracy, it is often sufficient to avoid even the skew being chained to the next medium.

  The present invention has been made in view of the above, and an object of the present invention is to provide a medium supply apparatus and an image reading apparatus that can suppress a chain of medium skew states with a simple configuration.

  In order to solve the above-described problems, the medium supply device according to the present invention is rotated by a driving force from a single driving source transmitted to one feeding shaft and transports the medium in the transport direction. A feeding roller having pressure, a brake means for contacting the feeding roller and applying a predetermined conveying load to the medium that has entered between the feeding roller, and a downstream side in the conveying direction of the feeding roller And a feeding roller disposed between the feeding roller and the feeding shaft between the feeding roller and the feeding shaft in a feeding rotation direction in which the roller carries the medium in the feeding direction. Rotation restricting means that allows rotation and restricts rotation in the direction opposite to the conveyance rotation direction is individually disposed, and the drive source converts the peripheral speed of the feeding roller to the peripheral speed of the conveyance roller. Characterized in that it is a more relatively slower controllable.

  In addition, the medium supply device includes a medium detection unit that is disposed on the downstream side in the conveyance direction of the feeding roller and detects the medium, and the medium has entered the conveyance roller by the medium detection unit. Is detected, it is preferable to execute control that causes the peripheral speed of the feeding roller to be relatively slower than the peripheral speed of the transport roller by the drive source.

  In the medium supply device, it is preferable that when the medium detection unit detects that the medium has entered the transport roller, the medium supply device performs control to stop the rotation of the feeding shaft by the drive source.

  In addition, the medium supply device includes a pickup roller having at least two rollers that can be rotated around one rotation shaft and is disposed on the upstream side in the conveyance direction of the feeding roller, and the roller that the pickup roller has Rotation that allows the roller to rotate in the conveyance rotation direction for conveying the medium in the conveyance direction and restricts rotation in the direction opposite to the conveyance rotation direction between each of the rotation axis and the rotation shaft It is preferable that the restricting means is individually arranged.

  In the medium supply device, it is preferable that the entire width of the feed roller in the feed axis direction is smaller than the width of the minimum set size of the medium.

In the medium supply device, the entire width of the feeding roller in the feeding axis direction is L1, the width of each of at least two rollers of the feeding roller is L2, and the number of the rollers of the feeding roller is n. As
n · L2 / L1 ≦ 0.95
It is preferable to satisfy.

  In order to solve the above-described problem, an image reading apparatus according to the present invention is disposed on the downstream side of the medium supply apparatus, the medium supply apparatus, and reads an image on the medium. It is preferable that a correction unit that corrects the inclination of the image of the medium read by the reading unit is provided.

  In the medium supply device according to the present invention, even when the medium that has entered the conveyance roller from the feeding roller is in a skew state, the rotation regulating means disposed on each roller of the feeding roller brings the roller into contact with the medium. Accordingly, each roller behaves differently, so that it is possible to suppress the skew from being transmitted to the next medium to be fed, and as a result, it is possible to suppress the chain of the skew state of the medium with a simple configuration. .

FIG. 1 is a cross-sectional view showing a schematic configuration of an image reading apparatus equipped with a medium supply apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view showing a schematic configuration when the medium supply device according to the first embodiment of the present invention is viewed from the direction of arrow A1 shown in FIG. FIG. 3 is a plan view for explaining the skew chain suppression operation by the medium supply device according to the first embodiment of the present invention. FIG. 4 is a plan view for explaining the skew chain suppression operation by the medium supply device according to the first embodiment of the present invention. FIG. 5 is a plan view for explaining the skew chain suppression operation by the medium supply device according to the first embodiment of the present invention. FIG. 6 is a graph for explaining the effect of suppressing the skew chain according to the first embodiment of the present invention. FIG. 7 is a cross-sectional view showing a schematic configuration of an image reading apparatus equipped with a medium supply device according to the second embodiment of the present invention. FIG. 8 is a plan view for explaining the skew chain suppression operation by the medium supply device according to the second embodiment of the present invention. FIG. 9 is a plan view for explaining the skew chain suppression operation by the medium supply device according to the second embodiment of the present invention. FIG. 10 is a plan view for explaining the skew chain suppression operation by the medium supply device according to the second embodiment of the present invention. FIG. 11 is a cross-sectional view showing a schematic configuration of an image reading apparatus equipped with a medium supply device according to the third embodiment of the present invention.

  Hereinafter, embodiments of a medium supply device and an image reading device according to the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS.

  First, the configuration of a medium supply device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a schematic configuration of an image reading apparatus equipped with a medium supply apparatus according to the first embodiment of the present invention, and FIG. 2 shows the medium supply apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view showing a schematic configuration when viewed from the direction of an arrow A1 shown in FIG.

  As shown in FIG. 1, the medium supply device 1 according to the present embodiment is a device that separates and supplies one by one from a plurality of stacked sheet-like media S. The medium supply device 1 is applied to, for example, an automatic document feeder (ADF) installed in an image reading device such as an image scanner, a copying machine, a facsimile, a character recognition device, or an image forming device such as a printer. The In the present embodiment, as an example, a case where the medium supply apparatus 1 is mounted on the image reading apparatus 10 and separates and conveys the sheet-like medium S will be described. The sheet-like medium S includes, for example, a sheet-like reading object such as a document or a business card, or a sheet-like recording medium such as a printing paper or a sheet.

  The medium supply device 1 is capable of supplying a plurality of types of media, and feeds the plurality of types of media with the center position of the medium in the width direction orthogonal to the transport direction as a reference position. The paper feed standard method is adopted. As shown in FIG. 1, the medium supply device 1 includes a feeding roller 2, a brake roller 3 (brake means), a conveyance roller 4, and a medium sensor 13 (medium detection) on a conveyance path that conveys the medium in the conveyance direction. Means) and a control device 7.

  The feeding roller 2 is a roller for feeding out the lowest medium S1 to be transported in the transport direction among a plurality of media S stacked on a hopper (not shown). As shown in FIGS. 1 and 2, the feed roller 2 includes a feed shaft 21 disposed substantially orthogonal to the transport direction, and two rollers 22 a and 22 b provided around the feed shaft 21. . The feeding shaft 21 is disposed below the medium conveyance path, and is rotationally driven by the operation of the motor 8 controlled by the control device 7.

  As shown in FIG. 2, the rollers 22a and 22b of the feeding roller 2 are arranged with a medium conveyance center C interposed therebetween in a direction substantially orthogonal to the conveyance direction. The rollers 22a and 22b are formed in a cylindrical shape by using a soft material that easily forms a nip width such as foam rubber in the inner layer, and one of the stacked media S that is closest to the feeding roller 2 is formed. The medium S1 can be contacted on the circumferential surface thereof. That is, the rollers 22a and 22b are rotated by the driving force transmitted from the motor 8, which is a single driving source, to the feeding shaft 21, thereby conveying the medium S1 that is in contact with the peripheral surface in the conveying direction. Can be conveyed.

  Further, as shown in FIG. 2, the feed roller 2 has a full width L1 in the direction of the feed shaft 21 that is smaller than the width of the minimum set size of the medium S. The medium S of a size is configured to be able to contact both the rollers 22a and 22b of the feeding roller 2.

In addition, as shown in FIG. 2, the feeding roller 2 has a total width L1 in the direction of the feeding shaft 21 of the feeding roller 2, L2 as the width of each of the rollers 22a and 22b, and the number of rollers of the feeding roller 2 as n. (N = 2 in this embodiment)
n · L2 / L1 ≦ 0.95
The feed roller 2 is configured so that a gap can be appropriately provided between the two rollers 22a and 22b. As a result, the inner surfaces of the rollers 22a and 22b can be prevented from coming into contact with each other, and the rollers 22a and 22b can be prevented from being obstructed by the contact between the rollers 22a and 22b.

  As shown in FIGS. 1 and 2, one-way clutches 14 a and 14 b (rotation restricting means) are individually provided between the two rollers 22 a and 22 b of the feeding roller 2 and the feeding shaft 21. . The one-way clutches 14a and 14b are arranged so as to allow the rollers 22a and 22b to rotate in the transport rotation direction for transporting the medium S1 to be transported in the transport direction and to restrict the rotation in the direction opposite to the transport rotation direction. Has been.

  That is, the rollers 22a and 22b of the feeding roller 2 can be integrally rotated by the driving force transmitted from the motor 8 as a single driving source to the feeding shaft 21, and the one-way clutch 14a provided in each of them. , 14b can be individually operated for rotation or stop.

  As specific configurations of the one-way clutches 14a and 14b, for example, a roller type, a cam type, a coil spring type, a ratchet type, a sprag type, and the like can be applied. Moreover, it is good also as a structure which arrange | positions support members, such as a sintered bearing, a resin bearing, a ball bearing, on the axial direction both sides of the one-way clutch 14a, 14b, and supports the radial load applied to the one-way clutch 14a, 14b.

  Note that the feeding roller 2 is generally a consumable item, and is appropriately replaced with use. The replacement unit of the feed roller 2 includes, for example, (1) a drive gear shaft integrated type including a feed shaft 21, rollers 22a and 22b, and a gear connecting the feed shaft 21 and the motor 8, and (2) a roller 22a. , 22b are integrally formed with the one-way clutches 14a, 14b provided therein, and are integrated with a roller that can be separated from the feeding shaft 21, and (3) the rollers 22a, 22b have the one-way clutches 14a, 14b inside, respectively. One roller type (including one-way clutch) that can be separated from the feeding shaft 21 in a state of being equipped, (4) One roller type that can separate each roller 22a, 22b from the one-way clutch 14a, 14b (one-way clutch is Another).

  The brake roller 3 is a roller for preventing a medium other than the single medium S1 to be conveyed among the plurality of mediums S stacked on a hopper (not shown) from being fed out in the conveying direction. The brake roller 3 is provided to face the feeding roller 2 and is in contact with the feeding roller 2. In the present embodiment, “contact pressure” means a state of pressing with an arbitrary contact pressure.

  The brake roller 3 includes a shaft 31 disposed substantially orthogonal to the conveying direction, and two rollers 32 a and 32 b provided around the shaft 31. The rollers 32a and 32b are arranged with the medium conveyance center C interposed therebetween in a direction substantially orthogonal to the conveyance direction. The rollers 32a and 32b are formed in a cylindrical shape using a soft material that easily forms a nip width such as foamed rubber in the inner layer.

  The rollers 32 a and 32 b of the brake roller 3 are in contact with the rollers 22 a and 22 b of the feeding roller 2. Thereby, between the roller 32a of the brake roller 3 and the roller 22a of the feeding roller 2, and between the roller 32b of the brake roller 3 and the roller 22b of the feeding roller 2, there is a contact surface between both rollers. A nip is formed. The medium S passes through the nip between the feed roller 2 and the brake roller 3 and is fed downstream in the transport direction. The nip width, which is the length of the nip in the conveying direction, can be adjusted by the degree of contact pressure of the brake roller 3 to the feeding roller 2.

  The brake roller 3 is configured to be driven to rotate according to the rotation of the feed roller 2 when receiving a torque greater than a predetermined driven rotational torque, and to generate a predetermined rotational load when receiving a torque smaller than the driven rotational torque. Has been. Specifically, such a configuration employs an FRR method in which the shaft 31 is a drive shaft and the shaft 31 rotates in a direction opposite to the conveyance direction to generate a load, or a simple FRR method in which the shaft 31 does not rotate in reverse. It can be realized by applying.

  When only one medium enters the nip, the brake roller 3 is driven and rotated by receiving a torque greater than the driven rotation torque, but when other media are also fed together and enter the nip. Since the friction coefficient of the nip becomes relatively small, the brake roller 3 generates a rotational load, and the medium that has entered the nip other than the medium S1 to be conveyed on the feeding roller 2 side is compared with the medium S1 to be conveyed. The medium is relatively moved and separated, and only the medium S1 to be conveyed is sent out from the nip, and the other medium is held in the nip, so that the medium other than the single medium S1 to be conveyed is fed out in the conveying direction. To prevent.

  The transport roller 4 is disposed on the downstream side in the transport direction of the feed roller 2 and transports the medium S1 that has passed through the feed roller 2 further downstream in the transport direction. The conveyance roller 4 includes a driving roller that is driven to rotate by a motor 9 and a driven roller that is driven to rotate by contact with the driving roller. The medium S1 passes between the driving roller and the driven roller and is conveyed downstream in the conveying direction.

  The medium sensor 13 is disposed on the transport path of the medium S1 and detects passage of the leading end of the medium S1. The medium sensor 13 is disposed immediately after the transport roller 4 in the transport direction. In the present embodiment, a pair of medium sensors 13 are arranged with the conveyance path of the medium S1 interposed therebetween, and face each other along the thickness direction of the medium S1. Then, it is detected that the medium S1 has passed between the opposing sensors. The medium sensor 13 may be disposed at an arbitrary position such as upstream of the conveyance roller 4 as long as it can detect that the medium S1 has entered the conveyance roller 4.

  An image reading unit 5 of the image reading device 10 is disposed on the downstream side of the conveying roller 4. When the medium S1 is conveyed to the reading position of the image reading unit 5 by the conveying roller 4, the image reading unit 5 scans the medium S1 and generates image data of the medium S1.

  A discharge roller 6 is further disposed on the downstream side of the image reading unit 5. The discharge roller 6 discharges the medium that has been read and scanned by the image reading unit 5 downstream. The discharge roller 6 includes a drive roller that is rotationally driven by a motor 9 and a driven roller that is driven to rotate by contact with the drive roller. That is, the transport roller 4 and the discharge roller 6 are configured to be rotatable by a common motor 9.

  The control device 7 controls each part of the medium supply device 1 and the image reading device 10. As shown in FIG. 1, the control device 7 is connected to the medium sensor 13, the motor 8, and the motor 9, and based on various sensor information such as the medium sensor 13, the feeding roller 2 to which the motor 8 is connected, The rotational drive of the conveyance roller 4 and the discharge roller 6 to which the motor 9 is connected is controlled. Further, although not shown in FIG. 1, the control device 7 is also connected to the image reading unit 5 and controls the image reading operation by the image reading unit 5.

  In particular, in the present embodiment, the control device 7 stops the operation of the motor 8 and determines that the medium S1 has reached the transport roller 4 when the medium sensor 13 detects the passage of the leading edge of the medium S1. Control for stopping the rotation of the roller 2 is performed. The control device 7 holds the image data of the medium S1 read by the image reading unit 5. Furthermore, the control device 7 (correction unit) can be configured to perform image processing for correcting the inclination of the image of the medium S1 read by the image reading unit 5.

  The control device 7 is physically a computer having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. All or part of each function of the control device 7 described above is realized by reading and writing data in the RAM or ROM by loading an application program held in the ROM into the RAM and executing it by the CPU. The

  Next, with reference to FIGS. 3 to 5, the operation of the medium carrying device according to the present embodiment will be described. 3 to 5 are plan views for explaining the skew chain suppression operation by the medium supply device according to the first embodiment of the present invention.

  3 to 5 are views of the feeding roller 2 and the conveying roller 4 of FIG. 1 viewed from the brake roller 3 side (the direction of the arrow A2 shown in FIG. 1). 3-5, the conveyance direction of the medium S is downward in the figure, and the medium S is conveyed from the upper side to the lower side in the figure. Further, among the stacked media S, only the first medium S1 that is the lowest and is the transport target, and only the second medium S2 that is stacked immediately above the medium S1 and is the next transport target of the medium S1. Is shown. That is, FIGS. 3 to 5 hierarchically illustrate the medium S2 first, the medium S1 next, and the feed roller 2 and the transport roller 4 in the back in the depth direction of the figure.

  As an initial state of the operation shown in FIGS. 3 to 5, the feeding roller 2 is rotationally driven in the direction of feeding the medium S <b> 1 in the transport direction by the motor 8, and the rollers 22 a and 22 b are also rotationally driven. The transport roller 4 on the downstream side in the transport direction from the feed roller 2 is also rotationally driven by the motor 9 in the direction of feeding the medium S1 in the transport direction. At this time, due to the influence of, for example, non-uniform pressure load between the rollers and per piece, the medium S1 to be transported is in a skew feeding state as shown in FIG. Consider a situation where the paper is inserted into the feed roller 2 with skew.

  When the medium S1 is inserted into the feeding roller 2, the feeding roller 2 comes into direct contact with the inserted medium S1 by the outer peripheral surfaces of the two rollers 22a and 22b. As shown in FIG. 3, the medium S <b> 1 receives a frictional force in the conveying direction from the outer peripheral surface of each of the rollers 22 a and 22 b of the feeding roller 2 by the rotational driving of the feeding roller 2 that contacts the medium S <b> 1. It is sent toward the downstream side of the direction. At this time, since the medium S1 is interposed between the second medium S2 stacked on the medium S1 and the feeding roller 2, the second medium S2 is in a non-contact state with the feeding roller 2, and in the transport direction. The power to is not transmitted.

  When the medium sensor 13 detects the passage of the medium S1, the control device 7 stops the motor 8 assuming that the medium S1 has reached the transport roller 4. Thereby, the rotation of the feeding roller 2 is stopped. At this time, the medium S1 is sent out to the downstream side in the transport direction by the rotational driving of the transport roller 4.

  As the medium S1 moves in the transport direction, the outer peripheral surfaces of the rollers 22a and 22b of the feeding roller 2 receive a frictional force f in the transport direction. This frictional force f is in the same direction as the frictional force that the medium S1 received from the rollers 22a and 22b by the rotational drive of the motor 8 described above. The one-way clutches 14a and 14b disposed between the rollers 22a and 22b and the feeding shaft 21 can be rotated by the frictional force f. Accordingly, both the rollers 22a and 22b are idled by the frictional force f, and are rotated by the rotational driving of the transport roller 4, so that the medium S1 is sent out in the transport direction.

  When the feeding of the medium S1 by the transport roller 4 proceeds, the medium S1 moves away from the feeding roller 2 and transitions to a state in which the second medium S2 is in contact with the feeding roller 2. As described above, since the skew is generated in the medium S1, in the process in which such a medium S1 is sent to the transport roller 4 side, as shown in FIG. 4, one roller 22a of the feeding roller 2 is provided. Is first separated from the medium S1, and the other roller 22b is in contact with the medium S1. In other words, the medium S1 passes through the nip of one roller 22a of the feeding roller 2 and is in the nip of the other roller 22b.

  At this time, the roller 22a from which the medium S1 has been removed does not receive the frictional force f in the transport direction from the medium S1, and therefore does not rotate following the transport roller 4 and stops rotating. For this reason, the roller 22a is in contact with the medium S2 to be fed next and the roller 22b, but does not pull it in. Furthermore, since the one-way clutch 14a restricts rotation in the direction opposite to the conveyance direction, even when the medium S2 receives a rotational load from the brake roller 3, the roller 22a does not rotate in the reverse direction due to this rotational load. There is also no behavior of returning to the direction opposite to the transport direction.

  On the other hand, the roller 22b that is in contact with the medium S1 receives the frictional force f in the conveyance direction by the medium S1, and thus idles due to the frictional force f and continues to rotate with respect to the conveyance roller 4. Since the medium S1 is still interposed between the medium S2 and the roller 22b, the medium S2 is not in contact with the roller 22b, and the frictional force f in the transport direction is not transmitted. That is, the medium S2 is in a different contact state with the rollers 22a and 22b of the feeding roller 2, but does not receive the rotational moment M in the skew angle direction.

  Then, as shown in FIG. 5, after the medium S1 has come out of the nips of both the rollers 22a and 22b of the feeding roller 2, the medium S2 does not transmit the skew of the medium S1, and the width direction of the medium S2 It is inserted into both rollers 22a and 22b of the feeding roller 2 at substantially the same timing while maintaining a posture substantially orthogonal to the transport direction.

  Next, effects of the medium supply device according to the present embodiment will be described.

  The medium supply apparatus 1 according to the present embodiment is rotated by a driving force from a single driving source (motor 8) transmitted to one feeding shaft 21, and has two rollers 22a for conveying the medium S1 in the conveying direction. A feeding roller 2 having 22 b, a brake roller 3 that is in contact with the feeding roller 2 to apply a predetermined conveying load to the medium S 2 that has entered between the feeding roller 2, and a conveying direction of the feeding roller 2 , And a medium sensor 13 that is disposed on the downstream side in the conveyance direction of the feeding roller 2 and detects the medium S1. In the medium supply device 1, between the rollers 22a and 22b of the feeding roller 2 and the feeding shaft 21, the rollers 22a and 22b rotate in the conveyance rotation direction for conveying the medium S1 in the conveyance direction. And one-way clutches 14a and 14b that individually restrict rotation in the direction opposite to the conveyance rotation direction. Further, when the medium sensor 13 detects that the medium S1 has entered the transport roller 4 by the medium sensor 13, the medium supply apparatus 1 executes control for stopping the rotation of the feeding shaft 21 by the motor 8.

  With this configuration, the one-way clutches 14a and 14b are individually arranged on the rollers 22a and 22b of the feeding roller 2, so that the left and right rollers 22a and 22b are in accordance with the contact state between the rollers 22a and 22b and the medium S1. Can behave differently. More specifically, for each of the rollers 22a and 22b, an operation of rotating following the rotation drive of the transport roller 4 while in contact with the medium S1 and an operation of stopping the rotation when not in contact with the medium S1. Can be done individually. As a result, even when a skew occurs in the medium S1 that has entered the transport roller 4 from the feed roller 2, the rotation of the feed shaft 21 by the motor 8 is stopped as the medium S1 enters the transport roller 4. If the control is performed, as described with reference to FIGS. 3 to 5, the left and right rollers 22 a and 22 b behave differently according to the contact state between the rollers 22 a and 22 b and the medium S <b> 1. It is possible to suppress the skew from being transmitted to the medium S2 to be fed to and to suppress the skew chain.

  Further, the feeding roller 2 is provided with the one-way clutches 14a and 14b for each of the rollers 22a and 22b, so that a single power source (motor) is conventionally provided without preparing a separate power source for each of the rollers 22a and 22b. It becomes possible to make each roller 22a, 22b perform a separate operation using only 8). As a result, the chain of skew states of the medium S can be suppressed with a simple configuration.

  Here, with reference to FIG. 6, the effect of suppressing the skew chain by the medium supply device 1 of the present embodiment will be described. FIG. 6 is a graph for explaining the effect of suppressing the skew chain according to the first embodiment of the present invention.

  FIG. 6 shows the number of sheets supplied when the A6 size medium S is set transversely to the transport direction (skew angle 0 degree) in the medium supply apparatus 1 of the present embodiment and is supplied without using the side guide. The skew angle is plotted. In addition, as a comparison target, experimental results in the related art including one common one-way clutch for each of the rollers 22a and 22b of the feeding roller 2 are also plotted.

  The horizontal axis in FIG. 6 indicates the number of sheets S supplied [sheets], and the vertical axis indicates the skew angle θ [deg]. Moreover, a white plot shows the experimental result of this embodiment, and a black plot shows the experimental result of the prior art.

  As shown in FIG. 6, in the prior art, as the number of fed sheets increases, the skew becomes obvious and tends to be gradually deteriorated. On the other hand, in the medium supply device 1 of the present embodiment, the skew angle θ is stable in the vicinity of 0 degrees even if the number of fed sheets is increased. As described above, it is shown that the present embodiment can suppress the deterioration of the skew.

  Further, in the medium supply device 1 of the present embodiment, the entire width L1 of the feed roller 2 in the direction of the feed shaft 21 is smaller than the width of the minimum set size of the medium S.

  Thereby, it is possible to enable contact with both the rollers 22a and 22b of the feeding roller 2 with respect to the medium S of all sizes targeted by the medium supply device 1, and to suppress skew chaining. Become.

In the medium supply device 1 of the present embodiment, the entire width of the feed roller 2 in the direction of the feed shaft 21 is L1, the widths of the two rollers 22a and 22b of the feed roller 2 are L2, and the feed roller 2 Let n be the number of rollers.
n · L2 / L1 ≦ 0.95
Meet.

  With this configuration, an appropriate gap can be provided between the two rollers 22 a and 22 b of the feeding roller 2. As a result, the inner surfaces of the rollers 22a and 22b can be prevented from coming into contact with each other, and the rollers 22a and 22b can be prevented from being obstructed by the contact between the rollers 22a and 22b.

  The image reading device 10 is arranged on the downstream side of the medium supply device 1, the image reading unit 5 that reads an image of the medium S, and the medium S read by the image reading unit 5. And a control device 7 for correcting the inclination of the image. As a result, the image data of the medium S can be subjected to image processing to correct the skew, so that the influence of the skew of the medium S can be further reduced to perform image reading.

[Modification of First Embodiment]
Note that the medium supply device 1 according to the present embodiment performs the operation when the medium sensor 13 detects that the medium S has entered the transport roller 4, instead of the operation of stopping the motor 8 of the feed roller 2. The motor 8 may be driven and controlled so that the peripheral speed of the feed roller 2 is relatively slower than the peripheral speed of the transport roller 4. In this case, in the operation of the medium supply device 1 shown in FIGS. 3 to 5, the motor 8 is switched from “drive” to “stop” in response to detection by the medium sensor 13. Change to switch to.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view showing a schematic configuration of an image reading apparatus equipped with a medium supply device according to the second embodiment of the present invention. 8 to 10 are plan views for explaining the skew chain suppression operation by the medium supply device according to the second embodiment of the present invention.

  As shown in FIG. 7, the medium supply device 1 a according to this embodiment has (1) a point that the feeding roller 2 and the conveying roller 4 are controlled by a single motor 15, and (2) the medium S is the conveying roller 4. This is different from the medium supply device 1 of the first embodiment in that the medium sensor 13 for detecting that the vehicle has entered is not provided.

  The motor 15 is connected to the feeding roller 2 and the conveying roller 4 via different gear trains (not shown), and rotationally drives the feeding roller 2 at a rotational speed V1 to drive the conveying roller 4 at a rotational speed V2. To rotate. These rotational speeds V1 and V2 are variable according to the driving force of the motor 15 controlled by the control device 7, but the relationship of V2> V1 is always maintained. In other words, in the medium supply device 1 a, the control device 7 can control the peripheral speed of the feed roller 2 relatively slower than the peripheral speed of the transport roller 4.

  Next, the operation of the medium supply device 1a will be described with reference to FIGS. The positional relationship among the feed roller 2, the transport roller 4, and the media S1 and S2 in FIGS.

  The feed roller 2 is rotationally driven at a peripheral speed V1 in a direction in which the medium S is sent in the transport direction by the motor 15. The transport roller 4 on the downstream side in the transport direction from the feed roller 2 is also rotationally driven at a peripheral speed V <b> 2 in a direction in which the medium S is sent out in the transport direction by the motor 15. At this time, as shown in FIG. 8, a situation is considered in which the medium S1 to be transported is inserted into the feed roller 2 with skew.

  When the medium S1 is inserted into the feeding roller 2, the feeding roller 2 comes into direct contact with the inserted medium S1 by the outer peripheral surfaces of the two rollers 22a and 22b. As shown in FIG. 8, the medium S <b> 1 receives a frictional force from the outer peripheral surface of each of the rollers 22 a and 22 b of the feeding roller 2 in the conveying direction by the rotational driving of the feeding roller 2 that contacts the medium S <b> 1. It is sent toward the downstream side of the direction. At this time, since the medium S1 is interposed between the second medium S2 stacked on the medium S1 and the feeding roller 2, the second medium S2 is in a non-contact state with the feeding roller 2, and in the transport direction. The power to is not transmitted.

  When the medium S1 reaches the transport roller 4, the medium S1 is simultaneously fed in the transport direction by the feeding roller 2 that is rotationally driven at the peripheral speed V1 and the transport roller 4 that is driven at the peripheral speed V2. Since V2> V1, the medium S1 is moving toward the conveying roller 4 at the relative speed V2-V1 when the feeding roller 2 is used as a reference.

  As the medium S1 moves in the transport direction, the outer peripheral surfaces of the rollers 22a and 22b of the feeding roller 2 receive a frictional force f in the transport direction. The frictional force f is in the same direction as the frictional force that the medium S1 receives from the rollers 22a and 22b by the rotational drive of the motor 15 described above. The one-way clutches 14a and 14b disposed between the rollers 22a and 22b and the feeding shaft 21 can be rotated by the frictional force f. Accordingly, both the rollers 22a and 22b are idled by the frictional force f, and are rotated by the rotational driving of the transport roller 4, so that the medium S1 is sent out in the transport direction.

  When the feeding of the medium S1 by the transport roller 4 proceeds, the medium S1 moves away from the feeding roller 2 and transitions to a state in which the second medium S2 is in contact with the feeding roller 2. As described above, since the medium S1 is in a skew state, in the process in which such a medium S1 is sent out to the transport roller 4 side, as shown in FIG. A state occurs in which the roller 22b is separated from the medium S1 and the other roller 22b is in contact with the medium S1. In other words, the medium S1 passes through the nip of one roller 22a of the feeding roller 2 and is in the nip of the other roller 22b.

  At this time, the roller 22a from which the medium S1 has come first does not receive the frictional force f in the transport direction from the medium S1, and therefore does not rotate following the transport roller 4. Furthermore, since the one-way clutch 14a restricts rotation in the direction opposite to the conveyance direction, even when the medium S2 receives a rotational load from the brake roller 3, the roller 22a does not rotate in the reverse direction due to this rotational load. There is also no behavior of returning to the direction opposite to the transport direction.

  On the other hand, the roller 22b that is in contact with the medium S1 receives the frictional force f in the conveyance direction by the medium S1, and thus idles due to the frictional force f and continues to rotate with respect to the conveyance roller 4. Since the medium S1 is still interposed between the medium S2 and the roller 22b, the medium S2 is not in contact with the roller 22b, and the frictional force f in the transport direction is not transmitted.

  Then, as shown in FIG. 10, after the medium S1 has come out of the nips of both the rollers 22a and 22b of the feeding roller 2, the medium S2 does not transmit the skew of the medium S1, and the width direction of the medium S2 It is inserted into both rollers 22a and 22b of the feeding roller 2 at substantially the same timing while maintaining a posture substantially orthogonal to the transport direction.

  As described above, the medium supply device 1a according to the present embodiment is rotated by the rotational force from the single drive source (motor 15) transmitted to one feed shaft 21, and transports the medium S1 in the transport direction 2. A feeding roller 2 having two rollers 22a and 22b, a brake roller 3 that contacts the feeding roller 2 and applies a predetermined conveying load to the medium S2 that has entered between the feeding roller 2 and a feeding roller. And a transport roller 4 disposed on the downstream side in the transport direction 2. In the medium supply device 1a, between each of the two rollers 22a and 22b of the feeding roller 2 and the feeding shaft 21, the rollers 22a and 22b rotate in the conveyance rotation direction for conveying the medium S1 in the conveyance direction. One-way clutches 14a and 14b that permit this and restrict rotation in the direction opposite to the conveyance rotation direction are individually arranged. Further, the medium supply device 1 a can control the peripheral speed V <b> 1 of the feeding roller 2 relatively slower than the peripheral speed V <b> 2 of the transport roller 4 by the motor 15.

  With such a configuration, even when the medium S1 entering the conveying roller 4 from the feeding roller 2 is in a skew state, as described with reference to FIGS. 8 to 10, the rollers 22a and 22b are in contact with the medium S1. Depending on the state, the left and right rollers behave differently, so that the skew can be prevented from being transmitted to the next medium S2 to be fed. Can be suppressed.

  The medium supply device 1a of the present embodiment is configured not to include the medium sensor 13, but may be configured to include the medium sensor 13 if the medium sensor 13 is not used for driving control of the feeding roller 2. .

[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view showing a schematic configuration of an image reading apparatus equipped with a medium supply device according to the third embodiment of the present invention.

  As shown in FIG. 11, the medium supply device 1 b of the present embodiment includes a pickup roller 16 on the upstream side in the transport direction of the feed roller 2, and the medium supply device 1 and the second embodiment of the first embodiment. This is different from the medium supply apparatus 1a.

  The pickup roller 16 is a roller for sending out the medium S1 to be transported in the lowermost layer among the stacked media S in the transport direction. The pickup roller 16 includes a rotating shaft 41 disposed substantially orthogonal to the transport direction, and two rollers 42 a and 42 b provided around the rotating shaft 41. The rotation shaft 41 is disposed below the conveyance path of the medium S and is rotationally driven by the operation of the motor 17 controlled by the control device 7. The rollers 42a and 42b are continuously arranged in a direction substantially orthogonal to the conveying direction, and are formed in a cylindrical shape using a soft material that easily forms a nip width such as foamed rubber in the inner layer, for example. The rollers 42a and 42b can contact the medium S1 to be conveyed from below on the circumferential surface thereof. The pickup roller 16 is rotated by the driving force transmitted from the motor 17 to the rotating shaft 41, and can contact the medium S1 to be transported from below to send out the medium S1 in the transport direction.

  Further, similarly to the feeding roller 2, one-way clutches 14a and 14b (rotation restricting means) are individually provided between the two rollers 42a and 42b of the pickup roller 16 and the rotation shaft 41, respectively. .

  With this configuration, even when the medium S1 that has entered the feeding roller 2 from the pickup roller 16 is in a skew state, the left and right rollers 42a are in accordance with the contact state between the left and right rollers 42a and 42b of the pickup roller 16 and the medium S1. , 42b behave differently, it is possible to suppress the skew from being transmitted to the next medium S2 to be fed, so that the skew chain can be further suppressed.

  As mentioned above, although embodiment of this invention was described, the said embodiment was shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  For example, the roller provided with the one-way clutches 14a and 14b may be the most upstream roller on the conveyance path of the medium S. In this case, when the most upstream roller on the conveyance path of the medium S is the feeding roller 2 as in the medium feeding device 1 of the first embodiment or the medium feeding device 1a of the second embodiment, the feeding roller 2 is provided with one-way clutches 14a and 14b. Further, in the configuration in which the pickup roller 16 is further provided upstream of the feeding roller 2 as in the medium supply device 1b of the third embodiment, the most upstream roller on the conveyance path of the medium S becomes the pickup roller 16, so that the pickup is performed. One-way clutches 14 a and 14 b are provided on the roller 16.

  In the above-described embodiment, the configuration in which the number of rollers included in the feeding roller 2, the brake roller 3, and the pickup roller 16 is two is illustrated. However, at least two feeding rollers 2, the brake roller 3, and the pickup roller 16 are included. As long as the roller is provided, three or more rollers may be provided.

  Further, the brake roller 3 according to the above-described embodiment can be applied to the medium S that has entered the space between the feeding roller 2 by contacting the feeding roller 2 with a predetermined pressure, for example, a separation pad or a separation belt. A configuration other than the brake roller 3 may be used.

  In the above-described embodiment, a type in which the lowermost one medium S1 among the plurality of mediums S stacked on the hopper is supplied as a conveyance target, that is, a so-called bottom take-out type medium supply device is illustrated. Can also be applied to an upper take-out type medium supply apparatus that feeds the uppermost medium of the medium S on the hopper as a conveyance target.

  In the above-described embodiment, a medium feeding reference type medium supply apparatus that feeds paper using the center position of the medium S in the width direction orthogonal to the transport direction as a reference position is illustrated, but the present invention is orthogonal to the transport direction. The present invention can also be applied to a medium supply apparatus of a one-side paper feed reference system in which one end side in the width direction is a reference position.

1, 1a, 1b Medium supply device 10 Image reading device 2 Feed roller 21 Feed shaft 22a, 22b Roller 3 Brake roller (brake means)
4 Conveying roller 5 Image reading unit 7 Control device (correction means)
8 Motor (drive source)
13 Medium sensor (medium detection means)
14a, 14b One-way clutch (rotation restricting means)
16 Pickup roller

Claims (7)

A feeding roller having at least two rollers that rotate by a driving force from a single driving source transmitted to one feeding shaft and that convey the medium in the conveying direction;
Brake means that contacts the feeding roller and applies a predetermined conveying load to the medium that has entered between the feeding roller;
A conveying roller disposed on the downstream side in the conveying direction of the feeding roller;
In a medium supply device comprising:
Between each of the rollers of the feed roller and the feed shaft, the roller is allowed to rotate in the transport rotation direction for transporting the medium in the transport direction, and rotates in the direction opposite to the transport rotation direction. Rotation restricting means for restricting rotation in the direction are individually arranged,
The medium supply device according to claim 1, wherein the drive source can control the peripheral speed of the feeding roller relatively slower than the peripheral speed of the transport roller. Arranged on the downstream side in the conveying direction of the feeding roller, and provided with a medium detecting means for detecting the medium,
When the medium detecting unit detects that the medium has entered the transport roller, the drive source performs control to make the peripheral speed of the feeding roller relatively slower than the peripheral speed of the transport roller. The medium supply device according to claim 1, wherein:   3. The medium according to claim 2, wherein when the medium detection unit detects that the medium has entered the transport roller, control is performed to stop rotation of the feeding shaft by the drive source. 4. Feeding device. A pickup roller having at least two rollers that can be rotated around one rotation axis, disposed on the upstream side in the conveying direction of the feeding roller;
Between each of the rollers of the pickup roller and the rotation shaft, the roller is allowed to rotate in the transport rotation direction for transporting the medium in the transport direction, and in a direction opposite to the transport rotation direction. The medium supply device according to any one of claims 1 to 3, wherein rotation restricting means for restricting the rotation of the medium is individually arranged.   5. The medium supply device according to claim 1, wherein a total width of the feed roller in the feed axis direction is smaller than a width of a minimum set size of the medium. The total width of the feeding roller in the feeding axis direction is L1, the width of each of at least two rollers of the feeding roller is L2, and the number of the rollers of the feeding roller is n.
n · L2 / L1 ≦ 0.95
The medium supply device according to claim 1, wherein: The medium supply device according to any one of claims 1 to 6,
An image reading unit disposed on the downstream side of the medium supply device and reading an image of the medium;
Correction means for correcting the inclination of the image of the medium read by the image reading unit;
An image reading apparatus comprising:

Images