Medium transport device

Abstract

To provide a medium carrying device capable of excellently switching whether or not to transmit driving force from a driving source to a separation roller.SOLUTION: The medium conveying apparatus includes a drive source configured to generate a driving force, a separation roller configured to separate a medium by the driving force, a mechanical clutch including a drive wheel configured to rotate by the driving force from the drive source and a driven wheel configured to transmit the driving force from the drive wheel to the separation roller in a state where the driven wheel is coupled to the drive wheel, and an application unit configured to apply a frictional force to the driven wheel.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a media transport device. [Background technology]

[0002] Generally, media transport devices such as scanners and printers have a separation roller that can separate media, and have a separation mode in which multiple media are transported while being separated, and a non-separation mode in which the media are transported without being separated.

[0003] A sheet feeding device is disclosed that includes a feeding unit that can switch between a separation mode in which sheets are separated and fed one by one from a sheet stacking unit and a non-separation mode in which sheets are fed without separation (see Patent Document 1). A retard roller of this sheet feeding device is connected to a clutch such as an electromagnetic clutch as part of a drive transmission system from a drive unit, and this clutch turns the drive of the retard roller on and off. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-188279 Summary of the Invention [Problem to be solved by the invention]

[0005] In a medium transport device, it is required to be able to smoothly switch whether or not to transmit a driving force from a driving source to a separation roller.

[0006] An object of the present invention is to provide a medium transport device that can effectively switch whether or not to transmit a driving force from a driving source to a separation roller. [Means for solving the problem]

[0007] A media conveying device according to one aspect of the present invention comprises a mechanical clutch including a drive source that generates a drive force, a separation roller that separates the media using the drive force, a drive wheel that rotates using the drive force from the drive source, and a driven wheel that can be switched between connection and disconnection with the drive wheel depending on the rotation of the drive wheel and that transmits the drive force from the drive wheel to the separation roller while connected to the drive wheel, and an application unit that applies a frictional force to the driven wheel that limits the rotation of the driven wheel relative to the drive wheel, and the frictional force applied by the application unit is greater than the frictional force between the drive wheel and the driven wheel. [Effects of the Invention]

[0008] According to the present invention, the medium transport device can effectively switch whether or not to transmit the driving force from the driving source to the separation roller. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view illustrating a medium transport device according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating a transport path inside the medium transport device. [Figure 3] FIG. 2 is a schematic diagram for explaining a drive mechanism. [Figure 4] 5(A) to 5(D) are schematic diagrams for explaining the operation of the clutch. [Figure 5] 5(A) to 5(D) are schematic diagrams for explaining the operation of the clutch. [Figure 6] 5A and 5B are schematic diagrams for explaining an application unit and a pressing unit. [Figure 7] FIG. 2 is a block diagram showing a schematic configuration of a medium transport device. [Figure 8] FIG. 2 is a diagram showing a schematic configuration of a storage device and a processing circuit. [Figure 9] 10 is a flowchart illustrating an example of the operation of a medium transport process. [Figure 10] FIG. 10 is a schematic diagram for explaining another application unit. [Figure 11] FIG. 10 is a diagram showing a schematic configuration of another processing circuit. DETAILED DESCRIPTION OF THE INVENTION

[0010] A medium transport device according to one aspect of the present invention will be described below with reference to the drawings. However, please note that the technical scope of the present invention is not limited to the embodiments described therein, but extends to the inventions set forth in the claims and their equivalents.

[0011] FIG. 1 is a perspective view showing a medium conveying device configured as an image scanner.

[0012] The medium conveying device 100 conveys, captures an image of, and discharges a medium that is an original. The medium may be paper, cardboard, a card, a booklet, a passport, etc. The medium conveying device 100 may also be a facsimile machine, a copier, a multifunction printer (MFP), etc.

[0013] 1, arrow A1 indicates the medium transport direction, arrow A2 indicates the width direction perpendicular to the medium transport direction, and arrow A3 indicates the height direction perpendicular to the medium transport path. Hereinafter, "upstream" refers to the upstream side of the medium transport direction A1, and "downstream" refers to the downstream side of the medium transport direction A1. The width direction A2 is an example of a direction that intersects with the medium transport direction.

[0014] The medium transport device 100 includes a lower housing 101, an upper housing 102, a loading table 103, an ejection table 104, a display operation device 105, and the like.

[0015] The upper housing 102 is disposed in a position that covers the top surface of the medium conveying device 100, and is engaged with the lower housing 101 by a hinge so that it can be opened and closed when a medium becomes jammed or when cleaning the inside of the medium conveying device 100, for example.

[0016] The mounting table 103 engages with the lower housing 101 and is rotatably provided by a hinge. When the medium conveying device 100 is not in use, the mounting table 103 is positioned to cover the lower housing 101 and the upper housing 102, and functions as an exterior cover. On the other hand, when the medium conveying device 100 is in use, the mounting table 103 is positioned to allow media to be placed thereon, and media to be fed and conveyed are placed on the mounting table 103. The discharge table 104 engages with the lower housing 101 and places discharged media on it. The discharge table 104 may also engage with the upper housing 102 by a hinge or the like.

[0017] The display operation device 105 has a display such as a liquid crystal display, an organic electroluminescence (EL) display, or the like, and an interface circuit for outputting image data to the display, and displays the image data on the display. The display operation device 105 also has a touch panel type input device and an interface circuit for acquiring signals from the input device, accepts operations by a user, and outputs signals according to the user's input. The display device and the operation device may be provided separately.

[0018] FIG. 2 is a diagram for explaining a transport path inside the medium transport device.

[0019] The transport path inside the medium transport device 100 includes a medium sensor 111, a feed roller 112, a separation roller 113, a first transport roller 114, a second transport roller 115, an imaging device 116, a first discharge roller 117, and a second discharge roller 118.

[0020] The number of each of the feed roller 112, separation roller 113, first conveyance roller 114, second conveyance roller 115, first discharge roller 117, and / or second discharge roller 118 is not limited to one, and may be multiple. In this case, the multiple feed rollers 112, separation rollers 113, first conveyance roller 114, second conveyance roller 115, first discharge roller 117, and / or second discharge roller 118 are arranged at intervals in the width direction A2. The first conveyance roller 114, second conveyance roller 115, first discharge roller 117, and / or second discharge roller 118 are examples of conveyance rollers.

[0021] The top surface of the lower housing 101 forms a lower guide 101a of the medium transport path, and the bottom surface of the upper housing 102 forms an upper guide 102a of the medium transport path. As shown in Fig. 2, the medium transport path has a so-called straight path mechanism in which the vertical positional relationship between the front and back surfaces of the medium does not change between the state before transport when the medium is placed on the loading tray 103 and the state after ejection when the medium is placed on the ejection tray 104. Because the medium transport path has a straight path mechanism, the medium transport device 100 can be formed compactly.

[0022] The media sensor 111 is disposed upstream of the feed roller 112 and the separation roller 113. The media sensor 111 has a contact detection sensor and detects whether or not a medium is placed on the placement table 103. The media sensor 111 generates and outputs a media signal whose signal value changes depending on whether or not a medium is placed on the placement table 103. Note that the media sensor 111 is not limited to a contact detection sensor, and any other sensor capable of detecting the presence or absence of a medium, such as an optical detection sensor, may be used as the media sensor 111.

[0023] The feed roller 112 is provided in the lower housing 101, and separates and feeds the media placed on the mounting table 103, starting from the bottom. The separation roller 113 is a so-called brake roller or retard roller, and is disposed in the upper housing 102 opposite the feed roller 112, and separates the media placed on the mounting table 103. The separation roller 113 is provided so as to be rotatable or stoppable in the direction A5 opposite the medium feeding direction. Note that a separation pad may be used instead of the separation roller 113.

[0024] The first conveying roller 114 and the second conveying roller 115 are disposed facing each other downstream of the feed roller 112 and the separation roller 113 in the medium conveying direction A1. The first conveying roller 114 and the second conveying roller 115 convey the medium fed by the feed roller 112 and the separation roller 113 to the imaging device 116.

[0025] The imaging device 116 captures an image of the medium transported by the first transport roller 114. The imaging device 116 includes a first imaging device 116a and a second imaging device 116b that are arranged opposite each other across the medium transport path.

[0026] The first imaging device 116a has an imaging sensor based on a CIS (Contact Image Sensor) of a life-size optical system having CMOS (Complementary Metal Oxide Semiconductor) imaging elements linearly arranged in the main scanning direction. The first imaging device 116a also has a lens that forms an image on the imaging element and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The first imaging device 116a captures images of the surface of the medium being transported, sequentially generating and outputting input images.

[0027] Similarly, the second imaging device 116b has an imaging sensor using a CIS of a 1x1 optical system with CMOS imaging elements arranged linearly in the main scanning direction. The second imaging device 116b also has a lens that forms an image on the imaging element and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The second imaging device 116b captures the back side of the medium being conveyed, sequentially generating and outputting line images.

[0028] The medium conveying device 100 may have only one of the first and second imaging devices 116a and 116b, and may read only one side of the medium. Alternatively, a CIS line sensor with a life-size optical system equipped with a CCD (Charge Coupled Device) imaging element may be used as the imaging sensor. Alternatively, a reduction optical system line sensor with a CMOS or CCD imaging element may be used as the imaging sensor.

[0029] The first discharge roller 117 and the second discharge roller 118 are disposed facing each other downstream of the imaging device 116 in the medium conveying direction A1. The first discharge roller 117 and the second discharge roller 118 discharge the medium that has been conveyed by the first conveying roller 114 and the second conveying roller 115 and processed (imaged) by the imaging device 116 onto the discharge tray 104.

[0030] The media placed on the mounting table 103 are transported between the lower guide 101a and the upper guide 102a in the media transport direction A1 by the rotation of the feed roller 112 in the direction of arrow A4 in FIG. 2, i.e., the media feed direction. The medium transport device 100 has two operating modes: a separation mode in which, when multiple media are placed on the mounting table 103, the media are separated and fed, and a non-separation mode in which the media are fed without being separated. When operating in the separation mode, the separation roller 113 rotates or stops in the direction of arrow A5, i.e., the opposite direction to the media feed direction, when feeding media. When multiple media are placed on the mounting table 103, the feed roller 112 and the separation roller 113 function to separate only the media placed on the mounting table 103 that are in contact with the feed roller 112. This restricts the transport of media other than the separated media (preventing double feeding). On the other hand, when operating in the non-separation mode, the separation roller 113 rotates in the opposite direction of the arrow A5, that is, in the medium feeding direction, following the feed roller 112 during medium feeding.

[0031] The medium is guided by lower guide 101a and upper guide 102a and fed between first conveyor roller 114 and second conveyor roller 115. The medium is fed between first imaging device 116a and second imaging device 116b as first conveyor roller 114 and second conveyor roller 115 rotate in the directions of arrows A6 and A7, respectively. The medium read by imaging device 116 is discharged onto discharge tray 104 as first discharge roller 117 and second discharge roller 118 rotate in the directions of arrows A8 and A9, respectively.

[0032] 3 is a schematic diagram for explaining the drive mechanisms of the separation roller, the transport roller, and the discharge roller, and is a perspective view of the drive mechanisms of the rollers as seen from above.

[0033] As shown in FIG. 3, the drive mechanism for the separation roller 113, the first conveying roller 114, and the first discharge roller 117 includes a first motor 121, first to third pulleys 122a to 122c, a belt 123, first to eleventh gears 124a to 124k, first to fourth shafts 125a to 125d, a torque limiter 126, a clutch 130, etc.

[0034] The first motor 121 is an example of a drive source, and generates a drive force for rotating the separation roller 113, the first conveyance roller 114, and the first discharge roller 117 in response to a control signal from a processing circuit (described later). The first motor 121 is, for example, a DC (Direct Current) motor. The first motor 121 may be a motor other than a DC motor, such as a stepping motor. The first motor 121 generates a drive force for rotating the separation roller 113 in the direction A5 opposite the medium feeding direction and for rotating the first conveyance roller 114, the second conveyance roller 115, the first discharge roller 117, and the second discharge roller 118 in the medium conveyance directions A6 to A9, respectively. The second conveyance roller 115 and the second discharge roller 118 may be driven rollers that rotate following the rotation of the first conveyance roller 114 and the first discharge roller 117, respectively. Furthermore, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117 and / or the second discharge roller 118 may be provided so as to rotate by a driving force generated by a motor other than the first motor 121.

[0035] A first pulley 122a is attached to the rotating shaft of the first motor 121, and a belt 123 is stretched between the first pulley 122a, second pulley 122b, and third pulley 122c. The second pulley 122b is attached to a first shaft 125a, to which a first discharge roller 117 is further attached. The third pulley 122c is attached to a second shaft 125b, to which a first conveyor roller 114 is further attached.

[0036] The gear portion of the third pulley 122c is engaged with the first gear 124a. The first gear 124a is engaged with the second gear 124b. The second gear 124b is engaged with the third gear 124c. The third gear 124c is engaged with the fourth gear 124d. The fourth gear 124d is engaged with the fifth gear 124e. The fifth gear 124e is engaged with the sixth gear 124f.

[0037] The clutch 130 is a mechanical clutch and includes a driving wheel 131 and a driven wheel 132. A gear is formed on the outer periphery of the driving wheel 131, and a sixth gear 124f is engaged with the driving wheel 131. The driven wheel 132 is provided so as to be switchable between connection and disconnection with the driving wheel 131. The driven wheel 132 is provided so as to rotate in conjunction with the seventh gear 124g.

[0038] The seventh gear 124g is engaged with the eighth gear 124h. The eighth gear 124h is attached to the third shaft 125c, and the ninth gear 124i is further attached to the third shaft 125c. The ninth gear 124i is engaged with the tenth gear 124j. The tenth gear 124j is engaged with the eleventh gear 124k. The eleventh gear 124k is attached to the fourth shaft 125d, and the separation roller 113 is further attached to the fourth shaft 125d.

[0039] A torque limiter 126 is provided on the fourth shaft 125d. The torque limiter 126 defines a limit value for the torque applied to the separation roller 113. The limit value of the torque limiter 126 is set to a value such that the rotational force via the torque limiter 126 is cut off when one medium is being conveyed, and the rotational force via the torque limiter 126 is transmitted when multiple media are being conveyed. As a result, when only one medium is being conveyed, the separation roller 113 does not rotate according to the driving force from the first motor 121 but instead follows the rotation of the feed roller 112. On the other hand, when multiple media are being conveyed, the separation roller 113 rotates in the direction A5 opposite the medium feeding direction to separate the medium in contact with the feed roller 112 from the other media, preventing double feeding. At this time, the outer circumferential surface of the separation roller 113 may apply a force in the direction A5 opposite the medium feeding direction to the media while the outer circumferential surface is stopped and not rotating in the direction A5 opposite the medium feeding direction.

[0040] The operation of each roller and its driving mechanism will be described below.

[0041] Hereinafter, of the driving forces generated by the first motor 121, the driving force that rotates in the direction of arrow B1 in FIG. 3 may be referred to as the "first driving force," and the driving force that rotates in the opposite direction of arrow B1 in FIG. 3 may be referred to as the "second driving force." When the first motor 121 generates the first driving force, the first pulley 122a rotates in the direction of arrow B1, and the second pulley 122b and the third pulley 122c rotate in the directions of arrows B2 and B3, respectively. As a result, the first discharge roller 117 rotates in the medium conveying direction A8 together with the first shaft 125a, which is the rotation axis, by the first driving force from the first motor 121, and conveys the medium. In addition, the first conveying roller 114 rotates in the medium conveying direction A6 together with the second shaft 125b, which is the rotation axis, by the first driving force from the first motor 121, and conveys the medium.

[0042] Although not shown, gears, pulleys, belts, or the like are provided between the gear portion of the third pulley 122c and the shaft that is the rotation axis of the second conveyance roller 115, and / or between the gear portion of the second pulley 122b and the shaft that is the rotation axis of the second discharge roller 118. As a result, the second conveyance roller 115 rotates in the medium conveyance direction A7 by the first driving force from the first motor 121, and conveys the medium. In addition, the second discharge roller 118 rotates in the medium conveyance direction A9 by the first driving force from the first motor 121, and conveys the medium.

[0043] Additionally, the first to sixth gears 124a-f rotate in the directions of arrows B4-B9, respectively, and the drive wheel 131 of the clutch 130 rotates in the direction of arrow B10. In this manner, the drive wheel 131 rotates due to the first drive force from the first motor 121. When the driven wheel 132 is coupled to the drive wheel 131, the seventh gear 124g, which rotates in conjunction with the driven wheel 132, rotates in the direction of arrow B10. The eighth to eleventh gears 124h-k rotate in the directions of arrows B11-B14, respectively. As a result, the separation roller 113 rotates in the direction A5 opposite the medium feeding direction together with the fourth shaft 125d, which is the rotation axis, due to the first drive force from the first motor 121, and separates the medium. In this manner, the driven wheel 132, coupled to the drive wheel 131, transmits the drive force from the drive wheel 131 to the separation roller 113. On the other hand, when the driven wheel 132 is not connected to the driving wheel 131, the driving force from the first motor 121 is not transmitted to the seventh to eleventh gears 124g-124k and is not transmitted to the separation roller 113.

[0044] When the first motor 121 generates the second driving force, the first conveyance roller 114, the second conveyance roller 115, the first discharge roller 117, and the second discharge roller 118 each rotate in the opposite direction to the medium conveying directions A6 to A9. Furthermore, when the first motor 121 generates the second driving force, the drive wheel 131 rotates in the opposite direction of arrow B10. At this time, if the driven wheel 132 is connected to the drive wheel 131, the separation roller 113 rotates in the medium feeding direction (the opposite direction of arrow A5 in FIG. 3) and feeds the medium. On the other hand, if the driven wheel 132 is not connected to the drive wheel 131, the driving force from the first motor 121 is not transmitted to the separation roller 113.

[0045] Figures 4(A) to (D) and 5(A) to (D) are schematic diagrams for explaining the operation of the clutch. In Figures 4(A) to (D) and 5(A) to (D), the right-hand diagrams are schematic diagrams of the inside of the drive wheel as seen from the opposite side of the driven wheel, and the left-hand diagrams are schematic diagrams of the inside of the driven wheel as seen from the opposite side of the drive wheel.

[0046] 4(A) to 4(D) and 5(A) to 5(D), the clutch 130 includes an operating wheel 133 in addition to the driving wheel 131 and the driven wheel 132. The operating wheel 133 is disposed inside the clutch 130.

[0047] A groove 131a is formed inside the drive wheel 131. The groove 131a includes a first groove 131b formed in an arc shape, and a second groove 131c and a third groove 131d formed to extend from the center of the first groove 131b toward the center of the drive wheel 131. A claw 131e is also provided inside the drive wheel 131 so as to be able to swing. The swing axis of the claw 131e is located closer to the center of the drive wheel 131 than the first groove 131b. A protrusion is formed at the swing end of the claw 131e so as to protrude toward the groove 131a so that the claw 131e can move within the groove 131a. The claw 131e is provided so as to be able to swing from a position blocking the entrance of the second groove 131c to a position blocking the entrance of the third groove 131d.

[0048] A plurality of recesses 132a are formed inside the driven wheel 132. Each recess 132a is formed in the center of the driven wheel 132 (closer to the center than the position facing the first groove portion 131b) so as to open from the center side of the driven wheel 132 toward the circumferential side.

[0049] An arm 133a is provided on the operating wheel 133. The arm 133a is provided so as to be able to swing around a swing shaft 133b. An arm pin 133c is provided at the swing end of the arm 133a. The arm pin 133c protrudes toward the driving wheel 131 side so as to move within the groove 131a, and also protrudes toward the driven wheel 132 side so as to be able to enter the recess 132a. A pressure is applied to the arm 133a by a pressure member (not shown), such as a torsion coil spring, so that the arm pin 133c moves toward the center of the driving wheel 131 and the driven wheel 132.

[0050] 4(A), the arm pin 133c is located at the end of the first groove portion 131b of the drive wheel 131 on the second groove portion 131c side, and the claw portion 131e is located at a position that blocks the entrance of the second groove portion 131c. At this time, the arm pin 133c is located outside the recessed portion 132a of the driven wheel 132, and the drive wheel 131 and the driven wheel 132 are not connected.

[0051] When the drive wheel 131 rotates a predetermined amount in the direction opposite to the arrow B10 from the state shown in Fig. 4(A), the groove 131a rotates in the direction opposite to the arrow B10, and the arm pin 133c is positioned near the entrance of the second groove 131c, as shown in Fig. 4(B). At this time, the swing end of the claw 131e is moved toward the third groove 131d by the arm pin 133c, opening the entrance of the second groove 131c.

[0052] When the drive wheel 131 rotates in the direction of arrow B10 from the state shown in FIG. 4(B), the arm pin 133c is applied with pressure by the pressure applying member so as to move toward the center of the drive wheel 131, and as shown in FIG. 4(C), the arm pin 133c enters the second groove portion 131c. On the driven wheel 132 side, the arm pin 133c engages with the recess 132a of the driven wheel 132. As a result, when the first motor 121 generates a first driving force and the drive wheel 131 rotates in the direction of arrow B10, the rotational force of the drive wheel 131 is transmitted to the driven wheel 132 via the arm 133a, and the driven wheel 132 rotates in conjunction with the rotation of the drive wheel 131. In this way, the driven wheel 132 is coupled to the drive wheel 131 so as to transmit the first driving force from the first motor 121 to the separation roller 113.

[0053] When the drive wheel 131 rotates in the direction opposite to the arrow B10 from the state shown in FIG. 4(C), the groove 131a rotates in the direction opposite to the arrow B10, and the arm pin 133c moves from the second groove 131c to the first groove 131b, as shown in FIG. 4(D). As a result, the arm pin 133c is positioned outside the recess 132a of the driven wheel 132, and the drive wheel 131 and the driven wheel 132 are disconnected. Thereafter, the arm pin 133c abuts against the claw 131e, causing the claw 131e to swing toward the third groove 131d and to be positioned to block the entrance of the third groove 131d. Although a pressure is applied to the arm pin 133c by the pressure member so as to move it toward the center of the drive wheel 131, the claw 131e prevents the arm pin 133c from entering the third groove 131d.

[0054] When the drive wheel 131 further rotates in the opposite direction of arrow B10 from the state shown in Figure 4(D), the groove portion 131a rotates in the opposite direction of arrow B10, as shown in Figure 5(A), and the arm pin 133c reaches the end of the first groove portion 131b of the drive wheel 131 on the third groove portion 131d side.

[0055] When the drive wheel 131 rotates a predetermined amount in the direction of arrow B10 from the state shown in Fig. 5(A), the groove 131a rotates in the direction of arrow B10, and the arm pin 133c is positioned near the entrance of the third groove 131d, as shown in Fig. 5(B). At this time, the swing end of the claw 131e is moved toward the second groove 131c by the arm pin 133c, opening the entrance of the third groove 131d.

[0056] When the drive wheel 131 rotates in the direction opposite to the arrow B10 from the state shown in FIG. 5(B), the arm pin 133c is applied with pressure by the pressure applying member so as to move toward the center of the drive wheel 131, and as shown in FIG. 5(C), the arm pin 133c enters the third groove portion 131d. On the driven wheel 132 side, the arm pin 133c engages with the recessed portion 132a of the driven wheel 132. As a result, when the first motor 121 generates a second driving force and the drive wheel 131 rotates in the direction opposite to the arrow B10, the rotational force of the drive wheel 131 is transmitted to the driven wheel 132 via the arm 133a, and the driven wheel 132 rotates in conjunction with the rotation of the drive wheel 131. In this way, the driven wheel 132 is coupled to the drive wheel 131 so as to transmit the second driving force from the first motor 121 to the separation roller 113.

[0057] When the drive wheel 131 rotates in the direction of arrow B10 from the state shown in FIG. 5(C), the groove 131a rotates in the direction of arrow B10, and the arm pin 133c moves from the third groove 131d to the first groove 131b, as shown in FIG. 5(D). As a result, the arm pin 133c is positioned outside the recess 132a of the driven wheel 132, and the drive wheel 131 and the driven wheel 132 are disconnected. Thereafter, the arm pin 133c abuts against the claw 131e, causing the claw 131e to swing toward the second groove 131c and to be positioned to block the entrance of the second groove 131c. Although a pressure is applied to the arm pin 133c by the pressure member so as to move toward the center of the drive wheel 131, the claw 131e prevents the arm pin 133c from entering the second groove 131c.

[0058] When the drive wheel 131 further rotates in the direction of arrow B10 from the state shown in Figure 5(D), the groove portion 131a rotates in the direction of arrow B10, as shown in Figure 4(A), and the arm pin 133c reaches the end of the first groove portion 131b of the drive wheel 131 on the second groove portion 131c side.

[0059] 4(A), if the drive wheel 131 continues to rotate in the direction opposite to the arrow B10, the claw 131e prevents the arm pin 133c from entering the third groove 131d, and the arm pin 133c reaches the end of the first groove 131b on the third groove 131d side. Similarly, if the drive wheel 131 continues to rotate in the direction of the arrow B10 from the state shown in FIG. 5(A), the claw 131e prevents the arm pin 133c from entering the second groove 131c, and the arm pin 133c reaches the end of the first groove 131b on the second groove 131c side. Therefore, if the drive wheel 131 continues to rotate in one direction in the state shown in FIG. 4(A) or FIG. 5(B), the driven wheel 132 is not coupled to the drive wheel 131, and the clutch 130 does not transmit the first driving force and the second driving force from the first motor 121 to the separation roller 113.

[0060] In this way, the driven wheels 132 are provided so as to be switchable between connection and disconnection with the driving wheels 131 by the rotation of the driving wheels 131 .

[0061] FIG. 6 is a schematic diagram for explaining the application unit and the pressing unit.

[0062] As shown in FIG. 6, the medium conveying device 100 further includes an applying unit 141 and a pressing unit 142.

[0063] The applying unit 141 is formed of rubber, resin, metal, or the like, and is provided so as to come into contact with the driven wheel 132. The applying unit 141 applies a frictional force to the driven wheel 132 that limits the rotation of the driven wheel 132 following the drive wheel 131. As described above, the driven wheel 132 is provided so as to be switchable between connection and disconnection with the drive wheel 131 by the rotation of the drive wheel 131. On the other hand, if the driven wheel 132 rotates along with the drive wheel 131 when the drive wheel 131 is rotated to switch between connection and disconnection of the drive wheel 131 and the driven wheel 132, it will be impossible to appropriately switch between connection and disconnection. The medium conveyance device 100 can appropriately switch between connection and disconnection with the drive wheel 131 by applying a frictional force to the driven wheel 132 that limits the rotation of the driven wheel 132 following the drive wheel 131.

[0064] The frictional force applied by the applying unit 141 is set in advance to be greater than the frictional force between the drive wheel 131 and the driven wheel 132. This allows the medium conveying device 100 to prevent the driven wheel 132 from rotating together with the drive wheel 131, and allows appropriate switching between connection and disconnection with the drive wheel 131.

[0065] Furthermore, the frictional force applied by the application unit 141 is preferably set to a magnitude that does not apply a load that separates the media to the separation roller 113 operating in the non-separation mode. In other words, the frictional force applied by the application unit 141 is preferably set to be smaller than the back load that separates the media by the separation roller 113. This allows the separation roller 113 to properly follow the feed roller 112 and feed the media well without separating the media when operating in the non-separation mode.

[0066] The applying portion 141 is provided so as to come into contact with the side surface of the driven wheel 132, i.e., the surface that intersects with the rotation axis, particularly the side surface opposite the drive wheel 131. This allows the applying portion 141 to efficiently apply a frictional force to the driven wheel 132 and appropriately suppress the rotation of the driven wheel 132.

[0067] The pressing portion 142 is a spring member such as a compression coil spring. The pressing portion 142 may be another spring member such as a leaf spring or a rubber member. One end of the pressing portion 142 is attached to a frame 102b fixed to the upper housing 102, and the other end of the pressing portion 142 is attached to the surface of the applying portion 141 opposite the driven wheel 132. The pressing portion 142 presses the applying portion 141 toward the driven wheel 132. This allows the medium conveyance device 100 to effectively apply to the driven wheel 132 a frictional force that limits the rotation of the driven wheel 132 following the drive wheel 131, and allows the drive wheel 131 and the driven wheel 132 to be appropriately connected and disconnected. Note that instead of the pressing portion 142, a fixing portion or the like may be provided to fix the applying portion 141 at a position where it contacts the driven wheel 132.

[0068] FIG. 7 is a block diagram showing a schematic configuration of the medium transport device.

[0069] In addition to the above-described configuration, the medium conveying device 100 further includes a second motor 151, an interface device 152, a storage device 160, a processing circuit 170, and the like.

[0070] The second motor 151 generates a driving force for rotating the feed roller 112 in response to a control signal from the processing circuit 170. The second motor 151 is, for example, a DC motor. The second motor 151 may be a motor other than a DC motor, such as a stepping motor. The second motor 151 generates a driving force for rotating the feed roller 112 in the medium feed direction A4. The feed roller 112 may be configured to be driven by the driving force from the first motor 121. Furthermore, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and / or the second discharge roller 118 may be configured to be driven by the driving force from the second motor 151.

[0071] The interface device 152 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (not shown) (for example, a personal computer, a personal digital assistant, etc.) to transmit and receive input images and various information. Instead of the interface device 152, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals via a wireless communication line in accordance with a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network). The communication unit may have a wired communication interface device for transmitting and receiving signals via a wired communication line in accordance with a communication protocol such as a wired LAN.

[0072] The storage device 160 includes a memory device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or optical disk. The storage device 160 also stores computer programs, databases, tables, and the like used for various processes of the medium conveying device 100. The computer programs may be installed into the storage device 160 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a CD-ROM (Compact Disc Read Only Memory) or a DVD-ROM (Digital Versatile Disc Read Only Memory). The computer programs may also be distributed from a server or the like and installed into the storage device 160.

[0073] The processing circuit 170 operates based on a program stored in advance in the storage device 160. The processing circuit is, for example, a CPU (Central Processing Unit). The processing circuit 170 may be a DSP (Digital Signal Processor), an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or the like.

[0074] The processing circuit 170 is connected to and controls the display operation device 105, the medium sensor 111, the imaging device 116, the first motor 121, the second motor 151, the interface device 152, the storage device 160, etc. Based on the medium signal acquired from the medium sensor 111, the processing circuit 170 performs drive control of the first motor 121 and the second motor 151, image capture control of the imaging device 116, etc. The processing circuit 170 acquires an input image from the imaging device 116 and transmits it to the information processing device via the interface device 152.

[0075] FIG. 8 is a diagram showing a schematic configuration of a storage device and a processing circuit.

[0076] 8, the storage device 160 stores a control program 161, an image acquisition program 162, and the like. Each of these programs is a functional module implemented by software running on a processor. The processing circuitry 170 reads each program stored in the storage device 160 and operates in accordance with the read program. As a result, the processing circuitry 170 functions as a control unit 171 and an image acquisition unit 172.

[0077] FIG. 9 is a flowchart illustrating an example of the operation of the medium conveyance process of the medium conveyance device.

[0078] An example of the operation of the medium conveying process of medium conveying device 100 will be described below with reference to the flowchart shown in Fig. 9. The flow of the operation described below is executed mainly by processing circuit 170 in cooperation with each element of medium conveying device 100 based on a program stored in memory device 160 in advance.

[0079] The control unit 171 sets the clutch 130 to connect the drive wheel 131 and the driven wheel 132 when the medium conveying device 100 is started (such as when the power is turned on or the mounting table 103 is opened). In particular, the control unit 171 connects the drive wheel 131 and the driven wheel 132 when the medium conveying device 100 is started so that the first drive force from the first motor 121 is transmitted to the separation roller 113. The control unit 171 drives the first motor 121 to rotate the drive wheel 131 by a first predetermined amount in the direction of arrow B10 (FIGS. 4 and 5), rotate it by a second predetermined amount in the direction opposite to the arrow B10, and further rotate it by a third predetermined amount in the direction of arrow B10. The first, second, and third predetermined amounts are determined in advance according to the specifications of the clutch 130. As a result, when the first motor 121 is subsequently driven to rotate the drive wheel 131 in the direction of arrow B10 (to generate a first drive force), the first drive force from the first motor 121 is transmitted to the first conveying roller 114, the second conveying roller 115, the first discharge roller 117, and the second discharge roller 118, as well as to the separation roller 113.

[0080] The separation roller 113 operates in either a separation mode or a non-separation mode. In the separation mode, the separation roller 113 separates the medium using a first driving force from the first motor 121. On the other hand, in the non-separation mode, the separation roller 113 feeds the medium using a second driving force from the first motor 121, and then the driving force from the first motor 121 is cut off and the separation roller 113 is driven by the feed roller 112. Typically, the non-separation mode is set when special media such as cards, booklets, or passports are being transported, and the separation mode is set when general paper is being transported. Therefore, in the medium transport device 100, the non-separation mode is generally set less frequently than the separation mode. By connecting the drive wheel 131 and the driven wheel 132 when the device is started, the medium transport device 100 reduces the possibility of needing to switch the clutch 130 during the medium transport process, thereby reducing the processing time for the medium transport process.

[0081] First, the control unit 171 waits until the user inputs an instruction to read a medium using the display operation device 105 or the information processing device, and an operation signal instructing the user to read a medium is received from the display operation device 105 or the interface device 152 (step S101). The operation signal includes the operation mode (separation mode / non-separation mode) of the medium conveying device 100 specified by the user using the display operation device 105 or the information processing device along with the instruction to read. Note that the operation mode may not be included in the operation signal, and may be set before the medium reading process is executed.

[0082] Next, control unit 171 acquires a medium signal from medium sensor 111, and determines whether or not a medium is placed on mounting table 103 based on the acquired medium signal (step S102). If no medium is placed on mounting table 103, control unit 171 ends the series of steps.

[0083] On the other hand, if a medium is placed on the placement table 103, the control unit 171 determines whether the operating mode of the medium conveying device 100 is the separation mode or the non-separation mode (step S103).

[0084] When the operating mode is the separation mode, the drive wheel 131 and the driven wheel 132 are already coupled to transmit the first driving force from the first motor 121 to the separation roller 113, so the control unit 171 does not switch the clutch 130. Next, the control unit 171 controls the first motor 121 and the second motor 151 to rotate the rollers and transport the medium (step S104). The control unit 171 causes the second motor 151 to generate a driving force to rotate the feed roller 112 in the medium feeding direction A4. The control unit 171 also causes the first motor 121 to generate a first driving force to rotate the separation roller 113 in the direction A5 opposite the medium feeding direction, and to rotate the first transport roller 114, the second transport roller 115, the first discharge roller 117, and the second discharge roller 118 in the medium transport directions A6 to A9, respectively.

[0085] Next, the image acquisition unit 172 causes the imaging device 116 to capture an image of the medium, acquires an input image from the imaging device 116, and outputs the acquired input image by transmitting it to the information processing device via the interface device 152 (step S105).

[0086] Next, control unit 171 determines whether or not a medium remains on mounting table 103 based on the medium signal received from medium sensor 111 (step S106). If a medium remains on mounting table 103, control unit 171 returns the process to step S105 and repeats the processes of steps S105 to S106.

[0087] On the other hand, if there are no media remaining on the mounting table 103, the control unit 171 controls the first motor 121 and the second motor 151 to stop the feed roller 112, the separation roller 113, the first conveying roller 114, the second conveying roller 115, the first discharge roller 117, and / or the second discharge roller 118 (step S107). At this time, the drive wheel 131 and the driven wheel 132 are connected to transmit the first drive force from the first motor 121 to the separation roller 113, so the control unit 171 does not switch the clutch 130 and ends the series of steps.

[0088] On the other hand, if the operating mode is the non-separation mode in step S103, the control unit 171 couples the drive wheel 131 and the driven wheel 132 to transmit the second drive force from the first motor 121 to the separation roller 113 (step S108). The control unit 171 drives the first motor 121 to rotate the drive wheel 131 by a fourth predetermined amount in the direction opposite to the arrow B10 (FIGS. 4 and 5), by a fifth predetermined amount in the direction of the arrow B10, and further by a sixth predetermined amount in the direction opposite to the arrow B10. The fourth, fifth, and sixth predetermined amounts are determined in advance according to the specifications of the clutch 130. As a result, when the first motor 121 is subsequently driven to rotate the drive wheel 131 in the opposite direction of the arrow B10 (to generate a second drive force), the second drive force from the first motor 121 is transmitted to the first conveying roller 114, the second conveying roller 115, the first discharge roller 117 and the second discharge roller 118, as well as to the separation roller 113.

[0089] Next, the control unit 171 controls the first motor 121 and the second motor 151 to rotate the rollers to transport the medium (step S109). The control unit 171 causes the second motor 151 to generate a driving force to rotate the feed roller 112 in the medium feed direction A4. The control unit 171 also causes the first motor 121 to generate a second driving force to rotate the separation roller 113 in the medium feed direction. At this time, the first transport roller 114, the second transport roller 115, the first discharge roller 117, and the second discharge roller 118 rotate in the direction opposite to the medium transport directions A6 to A9, respectively. However, because the leading edge of the medium has not yet reached the positions of the first transport roller 114, the second transport roller 115, the first discharge roller 117, and the second discharge roller 118, no problem occurs.

[0090] Next, the control unit 171 waits until the leading edge of the medium passes through the nip portion between the feed roller 112 and the separation roller 113 (step S109). For example, the control unit 171 determines that the leading edge of the medium has passed through the nip portion between the feed roller 112 and the separation roller 113 when a predetermined time has elapsed since the start of feeding of the medium. The predetermined time is set to the time required for the leading edge of the medium to move from the upstream end of the nip portion between the feed roller 112 and the separation roller 113 to the downstream end of the nip portion, plus a margin.

[0091] In addition, a second media sensor may be provided in the medium feeding device 100 between the feed roller 112 and the first transport roller 114 in the medium transport direction A1, particularly near the feed roller 112. The second media sensor includes, for example, a light emitter and a light receiver provided on one side of the medium transport path, and a light guide member provided opposite the light emitter and the light receiver across the medium transport path. The light guide member is a light guide tube such as a U-shaped prism. The light emitter is an LED (Light Emitting Diode) or the like, and emits light toward the transport path. Meanwhile, the light receiver is a photodiode or the like, and receives the light emitted by the light emitter and guided by the light guide member. Based on the intensity of the received light, the light receiver generates and outputs a second media signal whose signal value changes depending on whether a medium is present or absent at the position of the second media sensor. The second media sensor may also be a contact detection sensor or the like that passes a predetermined current when the medium is in contact with the sensor or when the medium is not in contact with the sensor. The control unit 171 determines that the leading edge of the medium has passed through the nip between the feed roller 112 and the separation roller 113 when the signal value of the second medium signal output from the second medium sensor changes from a value indicating that the medium is not present to a value indicating that the medium is present.

[0092] Next, the control unit 171 causes the first motor 121 to generate a first driving force, thereby disengaging the drive wheel 131 from the driven wheel 132 (step S111). As a result, when the first motor 121 is subsequently driven to rotate the drive wheel 131 in the direction of arrow B10 (to generate the first driving force), the first driving force from the first motor 121 is transmitted to the first conveyance roller 114, the second conveyance roller 115, the first discharge roller 117, and the second discharge roller 118, but is not transmitted to the separation roller 113. Therefore, the separation roller 113 is driven by the feed roller 112, and the first conveyance roller 114, the second conveyance roller 115, the first discharge roller 117, and the second discharge roller 118 convey the medium by the first driving force.

[0093] As described above, in the non-separation mode, there is a high possibility that special media, especially thick media, such as cards, booklets, or passports will be transported. When starting to feed the medium, the medium transport device 100 rotates the separation roller 113 using the second driving force from the first motor 121, thereby ensuring the medium feeding force and allowing the medium to be fed stably. After the medium has passed the separation roller 113, the medium transport device 100 causes the separation roller 113 to follow the feed roller 112, thereby reducing the load on the medium and preventing damage to the medium.

[0094] Next, the image acquisition unit 172 acquires an input image from the imaging device 116 in the same manner as in the process of step S105, and outputs the acquired input image by transmitting it to the information processing device via the interface device 152 (step S112).

[0095] Next, the control unit 171 controls the first motor 121 and the second motor 151 to stop the feed roller 112, the separation roller 113, the first conveying roller 114, the second conveying roller 115, the first discharge roller 117 and / or the second discharge roller 118 (step S113).

[0096] Next, control unit 171 determines whether or not a medium remains on mounting table 103 based on the medium signal received from medium sensor 111 (step S114). If a medium remains on mounting table 103, control unit 171 returns the process to step S108 and repeats the processes of steps S108 to S114.

[0097] On the other hand, if no media remain on the mounting table 103, the control unit 171 sets the clutch 130 to connect the drive wheel 131 and the driven wheel 132 in the same manner as when the medium conveying device 100 is started up (step S109), and ends the series of steps. In particular, the control unit 171 connects the drive wheel 131 and the driven wheel 132 to transmit the first driving force from the first motor 121 to the separation roller 113. As a result, when the first motor 121 is subsequently driven to rotate the drive wheel 131 in the direction of arrow B10 (to generate the first driving force), the first driving force from the first motor 121 is transmitted to the first conveyance roller 114, the second conveyance roller 115, the first discharge roller 117, and the second discharge roller 118, as well as to the separation roller 113.

[0098] In this way, after the medium conveyance is completed, the control unit 171 sets the clutch 130 to connect the drive wheel 131 and the driven wheel 132. This reduces the possibility that the medium conveyance device 100 will need to switch the clutch 130 in the next medium conveyance process, and can reduce the processing time for the medium conveyance process.

[0099] In step S108, the control unit 171 may disconnect the drive wheel 131 from the driven wheel 132 rather than connecting the drive wheel 131 and the driven wheel 132 so as to transmit the second drive force from the first motor 121 to the separation roller 113. In this case, the control unit 171 drives the first motor 121 to rotate the drive wheel 131 by a seventh predetermined amount in the direction opposite to the arrow B10 (FIGS. 4 and 5). The seventh predetermined amount is determined in advance according to the specifications of the clutch 130. In this case, in step S109, the control unit 171 causes the first motor 121 to generate a first drive force, thereby rotating the first conveyance roller 114, the second conveyance roller 115, the first discharge roller 117, and the second discharge roller 118 in the medium conveyance directions A6 to A9, respectively. This first drive force is not transmitted to the separation roller 112, and the separation roller 112 is driven by the feed roller 112.

[0100] Furthermore, the control unit 171 may couple the drive wheel 131 and the driven wheel 132 so as to transmit the second drive force from the first motor 121 to the separation roller 113 when the device is started up and / or after the medium transport is completed. In this case, if the control unit 171 determines in step S103 that the operation mode is the non-separation mode, it does not execute any particular process, but if it determines that the operation mode is the separation mode, it couples the drive wheel 131 and the driven wheel 132 so as to transmit the first drive force from the first motor 121 to the separation roller 113. Furthermore, the control unit 171 may release the coupling between the drive wheel 131 and the driven wheel 132 when the device is started up and / or after the medium transport is completed. Alternatively, the control unit 171 may not execute the setting of the clutch 130 when the device is started up and / or after the medium transport is completed. In these cases, if the control unit 171 determines in step S103 that the operation mode is the non-separation mode, it connects the drive wheel 131 and the driven wheel 132 so as to transmit the second drive force from the first motor 121 to the separation roller 113. On the other hand, if the control unit 171 determines in step S103 that the operation mode is the separation mode, it connects the drive wheel 131 and the driven wheel 132 so as to transmit the first drive force from the first motor 121 to the separation roller 113.

[0101] As described above in detail, the medium conveying device 100 applies a frictional force to the clutch 130, which is a mechanical clutch, that limits the rotation of the driven wheel 132 following the drive wheel 131. This makes it possible for the medium conveying device 100 to appropriately switch between coupling and non-coupling of the drive wheel 131 and the driven wheel 132, and to effectively switch between transmitting and not transmitting the driving force from the first motor 121 to the separation roller 113.

[0102] Furthermore, by using the clutch 130, which is a mechanical clutch, the media conveying device 100 eliminates the need to apply voltage to the clutch 130 during media separation, as opposed to when an electromagnetic clutch is used, thereby making it possible to reduce power consumption.

[0103] FIG. 10 is a schematic diagram for explaining an application unit in a medium transport device according to another embodiment.

[0104] The medium conveying device according to this embodiment has the same parts as the medium conveying device 100. However, the medium conveying device according to this embodiment has a supplying unit 241 and a pressing unit 242 instead of the supplying unit 141 and the pressing unit 142. The supplying unit 241 and the pressing unit 242 have the same configurations and functions as the supplying unit 141 and the pressing unit 142, respectively.

[0105] However, the providing unit 241 is provided so as to come into contact with the outer peripheral surface of the driven wheel 132. This allows the providing unit 241 to appropriately suppress the rotation of the driven wheel 132. Furthermore, by providing the providing unit 241 so as to come into contact with the outer peripheral surface of the driven wheel 132, the frictional force between the providing unit 241 and the driven wheel 132 can be easily adjusted, and the design cost of the medium conveying device can be reduced.

[0106] The applying portion 241 is provided so as to come into contact with the driven wheel 132 from above. This allows the applying portion 241 to efficiently suppress the rotation of the driven wheel 132 by utilizing its own weight.

[0107] One end of the pressing portion 242 is attached to a frame 102b fixed to the upper housing 102, and the other end of the pressing portion 242 is attached to the surface of the applying portion 241 opposite to the driven wheel 132. The pressing portion 242 presses the applying portion 241 toward the driven wheel 132. This allows the medium conveyance device to effectively apply to the driven wheel 132 a frictional force that limits the rotation of the driven wheel 132 following the drive wheel 131, and allows appropriate switching between connection and disconnection with the drive wheel 131. A weight may be used as the pressing portion 242 instead of a spring member, a rubber member, or the like.

[0108] The pressing unit 242 may be omitted. Even in this case, the applying unit 241 can suppress the rotation of the driven wheel 132 by its own weight. The medium conveying device can appropriately suppress the rotation of the driven wheel 132 while reducing the device cost and device weight.

[0109] As described above in detail, the media conveying device is now able to effectively switch whether or not to transmit the driving force from the first motor 121 to the separation roller 113, even when the application section 241 contacts the outer surface of the driven wheel 132 and / or when it contacts the driven wheel 132 from above.

[0110] FIG. 11 is a diagram showing a schematic configuration of a processing circuit in a medium conveyance device according to yet another embodiment.

[0111] The processing circuit 370 is used in place of the processing circuit 170 of the medium conveying device 100, and executes media reading processing and the like in place of the processing circuit 170. The processing circuit 370 includes a control circuit 371 and an image acquisition circuit 372. Note that these may each be configured as an independent integrated circuit, microprocessor, firmware, or the like.

[0112] The control circuit 371 is an example of a control unit, and has the same functions as the control unit 171. The control circuit 371 receives an operation signal from the display operation device 105 or the interface device 152, and a medium signal from the medium sensor 111. The control circuit 371 controls the first motor 121 and the second motor 151 based on the received information.

[0113] The image acquisition circuit 372 is an example of an image acquisition unit, and has the same function as the image acquisition unit 172. The image acquisition circuit 372 acquires an input image from the imaging device 116 and outputs it to the interface device 152.

[0114] As described above in detail, the medium conveying device can effectively switch whether or not to transmit the driving force from the first motor 121 to the separation roller 113, even when using the processing circuit 370.

[0115] Although the above has described preferred embodiments, the embodiments are not limited thereto. For example, the medium transport path of the medium transport device may have a so-called U-turn path mechanism, which feeds and transports the media placed on the loading tray from the top to the bottom and discharges them onto the discharge tray. In this case, the separation roller is disposed below the feed roller and faces the feed roller.

[0116] Furthermore, the medium transport device may have an image forming device instead of or in addition to the imaging device 116. The image forming device is a printer such as an inkjet type or laser type, and is placed at a position corresponding to the position where the imaging device 116 is placed, and forms an image (prints predetermined information) on the transported medium. [Explanation of symbols]

[0117] 100 medium conveying device, 112 feeding roller, 113 separation roller, 114 first conveying roller, 115 second conveying roller, 117 first discharge roller, 118 second discharge roller, 121 first motor, 130 clutch, 131 driving wheel, 132 driven wheel, 141, 241 applying section, 142, 242 pressing section, 171 control section

Claims

1. a driving source that generates a driving force; a separation roller that separates the medium by the driving force; a mechanical clutch including a drive wheel that rotates by a drive force from the drive source, and a driven wheel that is capable of switching between connection and disconnection with the drive wheel by the rotation of the drive wheel and that transmits the drive force from the drive wheel to the separation roller in a state that the driven wheel is connected to the drive wheel; an applying unit that applies a frictional force to the driven wheel to limit the rotation of the driven wheel following the drive wheel; The friction force applied by the application unit is greater than the friction force between the drive wheel and the driven wheel. A medium transport device characterized by:

2. It further has a feed roller, the separation roller operates in either a separation mode in which the separation roller separates the medium by the driving force or a non-separation mode in which the separation roller is driven by the feeding roller; 2. The media transport device of claim 1, wherein the friction force applied by the application unit is set to a magnitude that is greater than the friction force between the drive wheel and the driven wheel and does not apply a load that separates the media to the separation roller operating in the non-separation mode.

3. It further has a feed roller, the separation roller operates in either a separation mode in which the separation roller separates the medium by the driving force or a non-separation mode in which the separation roller is driven by the feeding roller; The medium transport device according to claim 1 , further comprising a transport roller that is disposed downstream of the separation roller in the medium transport direction and that transports the medium by the driving force.

4. The medium transport device according to claim 1 , further comprising a pressing portion that presses the application portion toward the driven wheel.

5. The medium transport device according to claim 1 , wherein the applying portion contacts the driven wheel from above.

6. The medium transport device according to claim 1 , wherein the applying portion contacts a surface of the driven wheel that intersects with the rotation axis of the driven wheel.

7. The medium transport device according to claim 1 , wherein the applying portion contacts an outer peripheral surface of the driven wheel.

8. The media transport device according to claim 1 , further comprising a control unit that sets the mechanical clutch to couple the drive wheel and the driven wheel when the device is started or after media transport is completed.

Images