Media transport device, control method, and control program

Abstract

Provided are a media conveyance device, a control method, and a control program, wherein when skewing of the media occurs, the media conveyance device is able to suitably correct the skewing of the media while stably conveying a large amount of media. This media conveyance device has: a placement base; a feeding roller for feeding the media placed on the placement base; a separation roller that is disposed opposite the feeding roller; a motor that generates a driving force; a plurality of conveying rollers that are disposed on the placement base upstream of the feeding roller and the separation roller in the media conveying direction and at intervals therebetween in a direction crossing the media conveying direction, the conveying rollers each rotating independently by means of the driving force and conveying the media; a determining unit that determines whether skewing of the media has occurred; and a control unit that controls the plurality of conveying rollers so as to correct the skewing of the media during feeding when it is determined that skewing of the media has occurred.

Description

Technical Field

[0001] The present disclosure relates to a medium conveyance device, a control method, and a control program, and particularly to a medium conveyance device, a control method, and a control program for correcting skew of a medium.

Background Art

[0002] A medium conveyance device such as a scanner that images while conveying a medium needs to convey a large amount of media together in order to improve the work efficiency of the user. In addition, in a medium conveyance device, skew (diagonal movement) may occur in which the medium is conveyed while being inclined, and the entire medium may not be imaged, or the medium may collide with the side wall of the conveyance path and cause a jam (paper jam) of the medium. In such a medium conveyance device, it is required to appropriately correct the skew of the medium while stably conveying a large amount of media.

[0003] A scanner is disclosed that includes a drive roller disposed at the center portion in the width direction of the apparatus on the paper placement surface, and a pair of driven rollers rotatably provided upstream of the drive roller in the feeding direction (see Patent Document 1). In this scanner, the pair of driven rollers are arranged symmetrically with respect to the center line of the paper placement surface in the width direction of the apparatus.

[0004] A sheet conveyance device is disclosed that includes a non-driven rotator that is rotatably supported around a first rotation axis located upstream of the separation unit in the conveyance direction and that can contact the lowermost sheet (see Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] In a media conveyance device, it is required to stably convey a large amount of media and appropriately correct the skew of the media when the skew of the media occurs.

[0007] An object of the media conveyance device, control method, and control program according to the embodiment is to be able to stably convey a large amount of media and appropriately correct the skew of the media when the skew of the media occurs.

[0008] A media conveyance device according to one aspect of the embodiment includes a mounting table, a feed roller for feeding the media mounted on the mounting table, a separation roller disposed opposite to the feed roller, a motor that generates a driving force, and a plurality of conveyance rollers that are disposed on the mounting table at intervals in a direction perpendicular to the media conveyance direction and upstream of the feed roller and the separation roller in the media conveyance direction, and that rotate independently by the driving force to convey the media. A one-way clutch that prevents the reverse rotation of the conveying roller, It has a determination unit that determines whether or not the skew of the media has occurred, and a control unit that controls the plurality of conveyance rollers so as to correct the skew of the media being fed when it is determined that the skew of the media has occurred.

[0009] Further, a control method according to one aspect of the embodiment is a control method of a media conveyance device, which feeds the media mounted on the mounting table by a feed roller, generates a driving force by a motor, and rotates a plurality of conveyance rollers that are disposed on the mounting table at intervals in a direction perpendicular to the media conveyance direction and upstream of the feed roller and the separation roller disposed opposite to the feed roller in the media conveyance direction, independently by the driving force to convey the media, determines whether or not the skew of the media has occurred, and controls the plurality of conveyance rollers so as to correct the skew of the media being fed when it is determined that the skew of the media has occurred. and 、 The one-way clutch prevents the reverse rotation of the conveying roller 。

[0010] Further, a control program according to an aspect of the embodiment includes a mounting table, a feed roller for feeding a medium mounted on the mounting table, a separation roller disposed opposite to the feed roller, a motor for generating a driving force, and a plurality of transport rollers that are disposed on the mounting table at intervals upstream of the feed roller and the separation roller in the medium transport direction and in a direction orthogonal to the medium transport direction, and that rotate independently by the driving force to transport the medium. , a one-way clutch that prevents the reverse rotation of the conveying roller A control program for a medium transport device having the above, which determines whether or not skew of the medium has occurred, and controls the plurality of transport rollers to correct the skew of the medium being fed when it is determined that skew of the medium has occurred, and causes the medium transport device to execute the above.

[0011] According to the present embodiment, the medium transport device, the control method, and the control program can appropriately correct the skew of the medium when the skew of the medium occurs while stably transporting a large amount of media.

[0012] The objects and effects of the present invention will be recognized and obtained by using the components and combinations particularly pointed out in the claims. Both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention described in the claims.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, a medium conveyance device, a control method, and a control program according to one aspect of the present disclosure will be described with reference to the drawings. However, note that the technical scope of the present invention is not limited to those embodiments, and extends to the invention described in the claims and its equivalents.

[0015] FIG. 1 is a perspective view showing a media conveyance device 100 configured as an image scanner. The media conveyance device 100 conveys, images, and discharges a medium that is an original. The medium may be paper, cardboard, a card, a booklet, a passport, or the like. The media conveyance device 100 may also be a facsimile machine, a copying machine, a multifunction peripheral (MFP), or the like.

[0016] In FIG. 1, arrow A1 indicates the media conveyance direction, arrow A2 indicates the width direction orthogonal to the media conveyance direction, and arrow A3 indicates the height direction orthogonal to the media conveyance path. Hereinafter, "upstream" refers to the upstream in the media conveyance direction A1, and "downstream" refers to the downstream in the media conveyance direction A1.

[0017] The media conveyance device 100 includes a lower housing 101, an upper housing 102, a placement table 103, a discharge table 104, an operation device 105, a display device 106, and the like.

[0018] The lower housing 101 is an example of a housing. The upper housing 102 is disposed at a position covering the upper surface of the media conveyance device 100 and is engaged with the lower housing 101 by a hinge so as to be openable and closable when loading the medium or cleaning the inside of the media conveyance device 100.

[0019] The placement table 103 is engaged with the lower housing 101 and places the medium to be fed and conveyed. The placement table 103 has a placement surface 103a for placing the medium.

[0020] The placement table 103 also has a first extension tray 103b and a second extension tray 103c. The first extension tray 103b is an example of an extension tray. The first extension tray 103b is provided so as to be pullable upstream in the medium conveyance direction A1 from the placement table 103. When not in use, the first extension tray 103b is stored inside the placement table 103, and when in use, it is pulled out from the placement table 103 to place the medium to be fed, particularly a medium with a large size. The second extension tray 103c is provided so as to be pullable further upstream from the first extension tray 103b. When not in use, the second extension tray 103c is stored inside the first extension tray 103b, and when in use, it is pulled out from the first extension tray 103b to place the medium to be fed, particularly a medium with an even larger size.

[0021] The first extension tray 103b and / or the second extension tray 103c may not be pullable and retractable, and may be foldably, detachably, or fixedly attached to the placement table 103 or the first extension tray 103b, respectively.

[0022] The discharge table 104 engages with the upper housing 102 and places the discharged medium. Note that the discharge table 104 may engage with the lower housing 101.

[0023] The operation device 105 has an input device such as a button and an interface circuit that acquires a signal from the input device, receives an input operation by the user, and outputs an operation signal corresponding to the user's input operation. The display device 106 has a display including a liquid crystal, an organic EL (Electro-Luminescence), etc., and an interface circuit that outputs image data to the display, and displays the image data on the display.

[0024] FIG. 2 is a schematic diagram for explaining the placement table 103. FIG. 2 is a perspective view of the placement table 103 in a state where it is removed from the lower housing 101 and the first extension tray 103b and the second extension tray 103c are stored.

[0025] As shown in FIG. 2, a plurality of first conveying rollers 111a and 111b, a plurality of contact detection sensors 112a and 112b, a plurality of driven rollers 113a and 113b, a plurality of side guides 114a and 114b, etc. are provided on the placement surface 103a of the placement table 103. Hereinafter, the first conveying rollers 111a and 111b, the contact detection sensors 112a and 112b, the driven rollers 113a and 113b, and the side guides 114a and 114b may be referred to as the first conveying rollers 111, the contact detection sensors 112, the driven rollers 113, and the side guides 114, respectively.

[0026] The plurality of first conveying rollers 111a and 111b are an example of a plurality of conveying rollers. The plurality of first conveying rollers 111a and 111b are arranged side by side on the placement table 103 at intervals in the width direction A2 orthogonal to the medium conveying direction. Each first conveying roller 111 is arranged so as to protrude from the placement surface 103a in the height direction A3, and conveys the medium placed on the placement table 103 toward the downstream side. The first conveying roller 111 is formed of a resin member such as POM (polyacetal), particularly a plastic member or a rubber member. The first conveying roller 111 is more preferably formed of a rubber member having a friction coefficient of 0.2 or more. Also, the friction coefficient of the first conveying roller 111 is preferably lower than the friction coefficients of the feeding roller and the separating roller described later. Thereby, the first conveying roller 111 can appropriately apply a conveying force to the medium while suppressing the occurrence of overfeeding of the medium (bending of the medium upstream of the feeding roller and the separating roller). Note that the number of the first conveying rollers 111 is not limited to two, and may be three or more.

[0027] The contact detection sensor 112 is an example of a sensor. A plurality of contact detection sensors 112a and 112b are respectively arranged around a plurality of first conveyance rollers 111a and 111b, and detect the contact between each of the plurality of first conveyance rollers 111a and 111b and the medium being fed by a feed roller. Each contact detection sensor 112 is arranged so as to overlap the corresponding first conveyance roller 111 in the width direction A2, that is, as viewed from the medium conveyance direction A1, and is arranged on the downstream side of the corresponding first conveyance roller 111 in the medium conveyance direction A1.

[0028] Each contact detection sensor 112 has an arm, a shielding member, a light emitter, and a light receiver, respectively. One end of the arm arranged inside the mounting table 103 is used as a rotation axis, and the other end projects outward from the mounting surface 103a of the mounting table 103 and is rotatably (oscillatably) attached so as to sink into the mounting table 103 by the medium placed on the mounting table 103. The shielding member is attached to the arm so as to rotate (oscillate) according to the rotation (oscillation) of the arm inside the mounting table 103.

[0029] The light emitter and the light receiver are arranged to face each other with the shielding member interposed therebetween. The light emitter irradiates light toward the light receiver. The light receiver receives the light irradiated by the light emitter and generates and outputs a contact detection signal, which is an electrical signal corresponding to the intensity of the received light. When the shielding member exists between the light emitter and the light receiver, the light irradiated by the light emitter is blocked by the shielding member, and when the shielding member does not exist between the light emitter and the light receiver, the light irradiated by the light emitter is received by the light receiver. Therefore, the signal value of the contact detection signal changes according to the position of the shielding member, that is, according to the position of the arm that moves together with the shielding member.

[0030] The arm is arranged such that the protruding amount from the placement surface 103a is smaller than the protruding amount from the placement surface 103a of the first conveyance roller 111. When the medium placed on the placement table 103 is placed on the first conveyance roller 111 and in contact with the first conveyance roller 111, the arm protrudes from the placement surface 103a without contacting the medium. On the other hand, when the rear end of the medium placed on the placement table 103 passes the position of the first conveyance roller 111 and separates from the first conveyance roller 111, the medium contacts the arm and the arm sinks into the placement table 103. The signal value of the contact detection signal changes when the medium placed on the placement table 103 changes from the state of being in contact with the first conveyance roller 111 to the state of separating from the first conveyance roller 111.

[0031] The plurality of driven rollers 113a, 113b are arranged at the central portion in the width direction A2 orthogonal to the medium conveyance direction on the placement table 103. Each driven roller 113 is arranged to protrude from the placement surface 103a in the height direction A3. Each driven roller 113 rotates in the direction of conveying the medium by being driven by the medium placed and fed on the placement table 103 to assist in the conveyance of the medium. The driven roller 113 is formed of a resin member such as POM (polyacetal), particularly a plastic member or a rubber member. In the example shown in FIG. 2, two driven rollers 113 are arranged side by side at intervals in the medium conveyance direction A1 at the central portion in the width direction A2. Note that the number of driven rollers 113 is not limited to two, and may be one or three or more. Also, each driven roller 113 may be arranged at an arbitrary position on the placement surface 103a.

[0032] The side guides 114 are provided to be movable in the width direction A2 and regulate the width direction of the medium placed on the placement table 103. The side guides 114a, 114b move in conjunction with each other so as to be always arranged symmetrically with respect to the central position of the placement table 103 in the width direction A2. Note that one of the side guides 114a, 114b may be fixed and only the other may be provided to be movable.

[0033] At the downstream end of the mounting table 103, an engaging portion 103d for engaging with the upstream end of the lower housing 101 is further provided. When the engaging portion 103d is engaged with the lower housing 101, the mounting table 103 is attached to the lower housing 101, and when the engagement between the engaging portion 103d and the lower housing 101 is released, the mounting table 103 is removed from the lower housing 101. Thus, the mounting table 103 is detachably provided on the lower housing 101.

[0034] FIG. 3 is a diagram for explaining the conveyance path inside the medium conveyance device 100.

[0035] The conveyance path inside the medium conveyance device 100 includes a medium sensor 121, a plurality of feed rollers 122a, 122b, a plurality of separation rollers 123a, 123b, a center sensor 124, a first side sensor 125, a second side sensor 126, a plurality of second conveyance rollers 127a, 127b, a plurality of third conveyance rollers 128a, 128b, an imaging device 129, a plurality of fourth conveyance rollers 130a, 130b, a plurality of fifth conveyance rollers 131a, 131b, and the like.

[0036] Hereinafter, the feed rollers 122a, 122b, the separation rollers 123a, 123b, the second conveyance rollers 127a, 127b, the third conveyance rollers 128a, 128b, the fourth conveyance rollers 130a, 130b, and the fifth conveyance rollers 131a, 131b may be respectively referred to as feed rollers 122, separation rollers 123, second conveyance rollers 127, third conveyance rollers 128, fourth conveyance rollers 130, and fifth conveyance rollers 131. Note that the number of each of the feed rollers 122, separation rollers 123, second conveyance rollers 127, third conveyance rollers 128, fourth conveyance rollers 130, and / or fifth conveyance rollers 131 is not limited to two, and may be one or three or more. When a plurality of each roller is provided, the rollers are arranged side by side at intervals in the width direction A2 orthogonal to the medium conveyance direction.

[0037] The upper surface of the lower housing 101 forms a lower guide 101a of the medium conveyance path, and the lower surface of the upper housing 102 forms an upper guide 102a of the medium conveyance path.

[0038] The media sensor 121 is disposed upstream of the feed roller 122 and the separation roller 123. The media sensor 121 has a contact detection sensor and detects whether a medium is placed on the mounting table 103. The media sensor 121 generates and outputs a media signal whose signal value changes between a state where a medium is placed on the mounting table 103 and a state where no medium is placed. Note that the media sensor 121 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 121.

[0039] The feed roller 122 is provided in the lower housing 101 and feeds the medium placed on the mounting table 103 in order from below. The separation roller 123 is provided in the upper housing 102 and is disposed opposite to the feed roller 122. Note that the feed roller 122 may be provided in the upper housing 102, the separation roller 123 may be provided in the lower housing 101, and the feed roller 122 may feed the medium placed on the mounting table 103 in order from above.

[0040] The second transport roller 127 and the third transport roller 128 are disposed opposite to each other downstream of the feed roller 122. The second transport roller 127 and the third transport roller 128 transport the medium fed by the feed roller 122 and the separation roller 123 to the imaging device 129.

[0041] The imaging device 129 is an example of an imaging unit and includes a first imaging device 129a and a second imaging device 129b disposed opposite to each other with the media transport path therebetween.

[0042] The first imaging device 129a has an imaging sensor of a contact image sensor (CIS) of an equal magnification optical system type having an imaging element made of CMOS (Complementary Metal Oxide Semiconductor) linearly arranged in the main scanning direction. Further, the first imaging device 129a has a lens that forms an image on the imaging element, and an A / D converter that amplifies an electrical signal output from the imaging element and performs analog / digital (A / D) conversion. The first imaging device 129a generates and outputs an input image obtained by imaging the surface of the conveyed medium.

[0043] Similarly, the second imaging device 129b has an imaging sensor of a CIS of an equal magnification optical system type having an imaging element made of CMOS linearly arranged in the main scanning direction. Further, the second imaging device 129b has a lens that forms an image on the imaging element, and an A / D converter that amplifies an electrical signal output from the imaging element and performs A / D conversion. The second imaging device 129b generates and outputs an input image obtained by imaging the back surface of the conveyed medium.

[0044] Note that the medium conveyance device 100 may arrange only one of the first imaging device 129a and the second imaging device 129b and read only one side of the medium. Further, as the imaging sensor, a line sensor of a CIS of an equal magnification optical system type including an imaging element made of a charge coupled device (CCD) may be used. Further, as the imaging sensor, a line sensor of a reduced optical system type including an imaging element made of CMOS or CCD may be used.

[0045] The fourth conveyance roller 130 and the fifth conveyance roller 131 are arranged to face each other on the downstream side of the imaging device 129 in the medium conveyance direction A1. The fourth conveyance roller 130 and the fifth conveyance roller 131 discharge the medium conveyed by the second conveyance roller 127 and the third conveyance roller 128 and imaged by the imaging device 129 to the discharge table 104.

[0046] The medium placed on the placement table 103 is conveyed between the lower guide 101a and the upper guide 102a in the medium conveyance direction A1 by the first conveyance roller 111 and the feeding roller 122 rotating in the directions of arrow A4 and arrow A5 in FIG. 3, that is, the medium feeding direction. When a large amount of media is placed on the placement table 103, the weight of the media placed on the upper side is applied to the media to be fed that is arranged on the lowermost side. Even when a large amount of media is placed on the placement table 103, since sufficient conveyance force is applied to the conveyed media by the first conveyance roller 111, the media is fed well. The separation roller 123 rotates in the direction of arrow A6, that is, the direction opposite to the medium feeding direction during medium conveyance. Due to the functions of the feeding roller 122 and the separation roller 123, when a plurality of media are placed on the placement table 103, only the media in contact with the feeding roller 122 among the media placed on the placement table 103 is separated. Thereby, the conveyance of the media other than the separated media is restricted (prevention of double feeding).

[0047] The medium is fed between the second conveyance roller 127 and the third conveyance roller 128 while being guided by the lower guide 101a and the upper guide 102a. The medium is fed between the first imaging device 129a and the second imaging device 129b by the second conveyance roller 127 and the third conveyance roller 128 rotating in the directions of arrow A7 and arrow A8 respectively. The medium read by the imaging device 129 is discharged onto the discharge table 104 by the fourth conveyance roller 130 and the fifth conveyance roller 131 rotating in the directions of arrow A9 and arrow A10 respectively.

[0048] FIG. 4 is a schematic diagram for explaining the arrangement positions of each roller and each sensor. FIG. 4 is a schematic diagram of the open medium conveyance device 100 viewed from above.

[0049] As shown in FIG. 4, the first conveyance roller 111 is disposed upstream of the feed roller 122 and the separation roller 123 in the medium conveyance direction A1. The first conveyance roller 111 applies a conveyance force to the medium placed on the mounting table 103 and is used to correct the skew of the medium when a skew (diagonal movement) occurs in which the medium is conveyed while being tilted. In the medium conveyance direction A1, the larger the distance L1 between the center position of the first conveyance roller 111 and the center position of the nip portion of the feed roller 122 and the separation roller 123, the larger the skew suppression moment, and the occurrence of skew is suppressed. On the other hand, the distance L1 needs to be set to a value smaller than the size of the medium for which the skew is to be corrected while applying the conveyance force. For example, the distance L1 is smaller than the size of the small medium (for example, 148 mm which is the length in the longitudinal direction of the A6 size), and is a value (for example, 138 mm) that is equal to or greater than the size obtained by subtracting a margin (for example, 10 mm) from the size of the small medium. Thereby, the first conveyance roller 111 can apply a conveyance force to the small medium and can appropriately correct the skew when the skew of the small medium occurs.

[0050] Also, in the width direction A2 orthogonal to the medium conveyance direction, the plurality of first conveyance rollers 111a, 111b are disposed sandwiching the feed roller 122 and the separation roller 123. That is, in the width direction A2 orthogonal to the medium conveyance direction, the plurality of first conveyance rollers 111a, 111b are respectively disposed outside (on the side guide 114a, 114b side) of the feed rollers 122a, 122b and the separation rollers 123a, 123b. The larger the distance L2 between the inner ends of the plurality of first conveyance rollers 111a, 111b in the width direction A2, the more efficiently the first conveyance roller 111 can rotate the medium and the more efficiently correct the skew of the medium. In particular, in the width direction A2, the distance L2 between the inner ends of the plurality of first conveyance rollers 111a, 111b is set to a value larger than the distance L3 between the outer ends of the plurality of feed rollers 122a, 122b. Thereby, the first conveyance roller 111 can efficiently correct the skew of the medium.

[0051] Also, similar to the distance L1, the distance L2 also needs to be set to a value smaller than the size of the medium for which skew is to be corrected while applying a conveying force. For example, the distance L1 is set to a value (e.g., 138 mm) that is smaller than the size of the small-sized medium (e.g., the longitudinal length of the A6 size, which is 148 mm) and equal to or greater than the size obtained by subtracting a margin (e.g., 10 mm) from the size of the small-sized medium. Thereby, the first conveying roller 111 can apply a conveying force to the small-sized medium and appropriately correct the skew when skew occurs in the small-sized medium.

[0052] The plurality of contact detection sensors 112a and 112b are arranged downstream of the first conveying roller 111 in the medium conveying direction A1 and overlap the corresponding first conveying rollers 111a and 111b when viewed from the medium conveying direction A1, that is, in the width direction A2. In particular, each of the contact detection sensors 112a and 112b is arranged close to the corresponding first conveying roller 111a and 111b. Thereby, the contact detection sensor 112 can more accurately determine whether the medium is in contact with the corresponding first conveying roller 111.

[0053] The driven roller 113 is arranged between the first conveying roller 111 and the feeding roller 122 and the separating roller 123, that is, downstream of the first conveying roller 111 and upstream of the feeding roller 122 and the separating roller 123 in the medium conveying direction A1. Also, in the width direction A2, the driven roller 113 is arranged in the region R between the two feeding rollers 122a and 122b (between the two separating rollers 123a and 123b). When the media bundle is placed on the mounting table 103, the placed media bundle is well guided downstream by the driven roller 113, so that it is well set at the feeding position of the media. Therefore, the media conveying device 100 can convey the media placed on the mounting table 103 well.

[0054] The center sensor 124, the first side sensor 125, and the second side sensor 126 are arranged downstream of the feeding roller 122 and the separating roller 123 and upstream of the second conveying roller 127 and the third conveying roller 128 in the medium conveying direction A1. Note that the center sensor 124, the first side sensor 125, and the second side sensor 126 may be arranged downstream of the second conveying roller 127 and the third conveying roller 128 and upstream of the imaging device 129 in the medium conveying direction A1. The center sensor 124, the first side sensor 125, and the second side sensor 126 are arranged side by side at intervals in the width direction A2. The center sensor 124 may be arranged upstream or downstream of the first side sensor 125 and the second side sensor 126.

[0055] The center sensor 124 is arranged at the center in the width direction A2, particularly between the two feeding rollers 122a and 122b (between the two separating rollers 123a and 123b). The first side sensor 125 and the second side sensor 126 are arranged outside the center sensor 124 in the width direction A2, that is, on the side walls Wa and Wb of the medium conveying path, respectively. The first side sensor 125 and the second side sensor 126 are arranged such that the distance in the width direction A2 between the first side sensor 125 and the second side sensor 126 is less than the minimum width of the medium supported by the medium conveying device 100.

[0056] The center sensor 124 includes a light emitter and a light receiver provided on one side with respect to the medium conveyance path, and a light guide member provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. 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 irradiates light toward the conveyance path. On the other hand, the light receiver is a photodiode or the like and receives the light irradiated by the light emitter and guided by the light guide member. When a medium exists at a position facing the center sensor 124, the light irradiated from the light emitter is blocked by the medium, so the light receiver does not detect the light irradiated from the light emitter. The light receiver generates and outputs a center signal whose signal value changes between a state where a medium exists and a state where no medium exists at the position of the center sensor 124 based on the intensity of the received light.

[0057] Similarly, the first side sensor 125 includes a light emitter and a light receiver provided on one side with respect to the medium conveyance path, and a light guide member provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light guide member is a light guide tube such as a U-shaped prism. The light emitter is an LED or the like and irradiates light toward the conveyance path. On the other hand, the light receiver is a photodiode or the like and receives the light irradiated by the light emitter and guided by the light guide member. The light receiver generates and outputs a first side signal whose signal value changes between a state where a medium exists and a state where no medium exists at the position of the first side sensor 125 based on the intensity of the received light.

[0058] Similarly, the second side sensor 126 includes a light emitter and a light receiver provided on one side with respect to the medium conveyance path, and a light guide member provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light guide member is a light guide tube such as a U-shaped prism. The light emitter is an LED or the like and irradiates light toward the conveyance path. On the other hand, the light receiver is a photodiode or the like and receives the light irradiated by the light emitter and guided by the light guide member. The light receiver generates and outputs a second side signal whose signal value changes between a state where a medium exists and a state where no medium exists at the position of the second side sensor 126 based on the intensity of the received light.

[0059] In addition, in the center sensor 124, the first side sensor 125, and / or the second side sensor 126, a reflecting member such as a mirror may be used instead of the light guide member. Further, in the center sensor 124, the first side sensor 125, and / or the second side sensor 126, the light emitter and the light receiver may be provided at positions facing each other across the conveyance path. Further, the center sensor 124, the first side sensor 125, and / or the second side sensor 126 may detect the presence of the medium by a contact detection sensor or the like that passes a predetermined current when the medium is in contact or when the medium is not in contact.

[0060] FIG. 5 is a schematic diagram for explaining the driving force transmission mechanism of the first conveyance roller 111. FIG. 5 is a schematic diagram of the periphery of the first conveyance roller 111 as viewed from above.

[0061] As shown in FIG. 5, the medium conveyance device 100 further includes first motors 132a, 132b, first transmission mechanisms 140a, 140b, and second transmission mechanisms 150a, 150b. The first transmission mechanisms 140a and 150a are mechanisms for transmitting the driving force from the first motor 132a to the first conveyance roller 111a. The first transmission mechanisms 140b and 150b are mechanisms for transmitting the driving force from the first motor 132b to the first conveyance roller 111b. The first transmission mechanisms 140a, 140b are examples of the first transmission unit and are provided in the lower housing 101. The second transmission mechanisms 150a, 150b are examples of the second transmission unit and are provided on the mounting table 103. Hereinafter, the first motors 132a, 132b, the first transmission mechanisms 140a, 140b, and the second transmission mechanisms 150a, 150b may be referred to as the first motor 132, the first transmission mechanism 140, and the second transmission mechanism 150, respectively.

[0062] The first motors 132a, 132b are examples of motors and are arranged in the lower housing 101, and generate driving forces for rotating the first conveyance rollers 111a, 111b, respectively, according to control signals from a processing circuit described later. Note that the first motor 132 may be arranged on the mounting table 103.

[0063] The first transmission mechanisms 140a and 140b each include a first belt 141a, 141b, a first gear 142a, 142b, a second gear 143a, 143b, a third gear 144a, 144b, a fourth gear 145a, 145b, etc. The second transmission mechanisms 150a and 150b each include a fifth gear 151a, 151b, a second belt 152a, 152b, a pulley 153a, 153b, a first shaft 154a, 154b, a one-way clutch 155a, 155b, etc.

[0064] Hereinafter, the fourth gears 145a and 145b and the fifth gears 151a and 151b may be referred to as the fourth gear 145 and the fifth gear 151, respectively. In the first transmission mechanism 140 and / or the second transmission mechanism 150, only one of the gear, or the pulley and the belt may be used. Also, the one-way clutches 155a and 155b may be omitted.

[0065] The first belts 141a and 141b are respectively stretched between the rotation shafts of the first motors 132a and 132b and the pulley portions of the first gears 142a and 142b. The gear portions of the first gears 142a and 142b are respectively engaged with the second gears 143a and 143b. The second gears 143a and 143b are respectively engaged with the third gears 144a and 144b. The third gears 144a and 144b are respectively engaged with the fourth gears 145a and 145b. The fourth gears 145a and 145b are respectively engaged with the gear portions of the fifth gears 151a and 151b.

[0066] The second belts 152a and 152b are respectively stretched between the pulley portions of the fifth gears 151a and 151b and the pulleys 153a and 153b. The pulleys 153a and 153b are respectively attached to the first shafts 154a and 154b via the one-way clutches 155a and 155b. The one-way clutches 155a and 155b are provided to prevent the first shafts 154a and 154b from rotating in the direction opposite to the rotation direction of the pulleys 153a and 153b. The first conveying rollers 111a and 111b are respectively attached to the first shafts 154a and 154b.

[0067] Next, the operations of the first transmission mechanism 140, the second transmission mechanism 150, and the first transport roller 111 will be described.

[0068] When the first motors 132a and 132b generate a driving force, the first belts 141a and 141b rotate in the direction of arrow A11. Accordingly, the first gears 142a and 142b, the second gears 143a and 143b, the third gears 144a and 144b, the fourth gears 145a and 145b, and the fifth gears 151a and 151b rotate in the directions of arrows A12, A13, A14, A15, and A16, respectively. Accordingly, the second belts 152a and 152b and the pulleys 153a and 153b rotate in the direction of arrow A16. As a result, the first transport rollers 111a and 111b rotate in the medium transport direction A17 together with the first shafts 154a and 154b that are the rotation shafts.

[0069] The plurality of first transport rollers 111a and 111b each rotate independently by the driving force from the first motors 132a and 132b to transport the medium. As a result, the first transport rollers 111a and 111b can apply different transport forces to different positions in the width direction A2 within the medium, and can appropriately correct the skew of the medium.

[0070] In addition, the first shafts 154a and 154b that are the rotation shafts of the plurality of first transport rollers 111a and 111b are arranged on the same straight line X. As a result, it is possible to suppress the application of a non-uniform transport force to the medium placed on the mounting table 103, and it is possible to suppress the occurrence of wrinkles in the medium or skew of the medium.

[0071] The first transmission mechanism 140 provided in the lower housing 101 is connected to the rotation shaft of the first motor 132 and is also connected to the second transmission mechanism 150 provided on the mounting table 103, and transmits the driving force from the first motor 132 to the second transmission mechanism 150. On the other hand, the second transmission mechanism 150 provided on the mounting table 103 is connected to the first transmission mechanism 140 provided in the lower housing 101, and transmits the driving force transmitted by the first transmission mechanism 140 to the plurality of first transport rollers 111.

[0072] The fourth gear 145 of the first transmission mechanism 140 and the fifth gear 151 of the second transmission mechanism 150 are provided so as to engage with each other when the mounting table 103 is attached to the lower housing 101 and to be separated from each other when the mounting table 103 is removed from the lower housing 101. Thereby, the medium conveying device 100 can rotate the first conveying roller 111 disposed on the mounting table 103 detachably provided on the lower housing 101 by the driving force from the first motor 132 disposed on the lower housing 101. Since no motor is provided in the mounting table 103, the medium conveying device 100 can reduce the weight of the mounting table 103. Thereby, the user can easily remove the mounting table 103 from the lower housing 101 and store it compactly, and the medium conveying device 100 can improve the convenience for the user.

[0073] Also, the one-way clutches 155a and 155b prevent the first shafts 154a and 154b from rotating in the direction opposite to the rotation direction of the pulleys 153a and 153b. Thereby, when the first motor 132 is stopped, the medium conveying device 100 can suppress the reverse rotation of the first conveying roller 111 due to the influence of the gap (so-called play) existing between the first shafts 154a and 154b and the pulleys 153a and 153b.

[0074] FIG. 6 is a block diagram showing a schematic configuration of the medium conveying device 100.

[0075] In addition to the above-described configuration, the medium conveying device 100 further includes a second motor 161, an interface device 162, a storage device 170, a processing circuit 180, and the like.

[0076] The second motor 161 includes one or more motors and rotates the feed roller 122, the separation roller 123, the second conveyance roller 127, the third conveyance roller 128, the fourth conveyance roller 130, and the fifth conveyance roller 131 according to a control signal from the processing circuit 180 to convey the medium. The feed rollers 122a and 122b are each driven by a separate motor and are provided to rotate independently to feed the medium, similar to the first conveyance rollers 111a and 111b. Note that one of the second conveyance roller 127 and the third conveyance roller 128 may be a driven roller that rotates following the other roller. Also, one of the fourth conveyance roller 130 and the fifth conveyance roller 131 may be a driven roller that rotates following the other roller.

[0077] The interface device 162 has an interface circuit conforming to a serial bus such as USB, for example, and is electrically connected to an information processing device (for example, a personal computer, a portable information terminal, etc.) (not shown) to transmit and receive an input image and various types of information. Further, instead of the interface device 162, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals through a wireless communication line according to 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 through a wired communication line according to a communication protocol such as a wired LAN.

[0078] The storage device 170 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 an optical disk. Further, the storage device 170 stores computer programs, databases, tables, etc. used for various processes of the media transport device 100. The computer program may be installed in the storage device 170 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), a DVD-ROM (digital versatile disc read only memory), or the like.

[0079] The processing circuit 180 operates based on a program stored in the storage device 170 in advance. The processing circuit is, for example, a CPU (Central Processing Unit). As the processing circuit 180, 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 may be used.

[0080] The processing circuit 180 is connected to an operating device 105, a display device 106, a contact detection sensor 112, a medium sensor 121, a center sensor 124, a first side sensor 125, a second side sensor 126, an imaging device 129, a first motor 132, a second motor 161, an interface device 162, a storage device 170, etc., and controls these respective parts. The processing circuit 180 performs drive control of the first motor 132 and the second motor 161, imaging control of the imaging device 129, etc., acquires an input image from the imaging device 129, and transmits it to an information processing device via the interface device 162. Further, the processing circuit 180 determines whether or not skew of the medium has occurred based on signals from the center sensor 124, the first side sensor 125, and the second side sensor 126, and when skew of the medium has occurred, controls the first motor 132 to correct the skew of the medium.

[0081] FIG. 7 is a diagram showing a schematic configuration of the storage device 170 and the processing circuit 180.

[0082] As shown in FIG. 7, a control program 171, a determination program 172, etc. are stored in the storage device 170. These respective programs are functional modules implemented by software operating on a processor. The processing circuit 180 reads each program stored in the storage device 170 and operates according to each read program. Thereby, the processing circuit 180 functions as a control unit 181 and a determination unit 182.

[0083] FIG. 8 is a flowchart showing an example of the operation of the medium reading process of the medium conveyance device 100.

[0084] Hereinafter, an example of the operation of the medium reading process of the medium conveyance device 100 will be described while referring to the flowchart shown in FIG. 8. Note that the operation flow described below is mainly executed by the processing circuit 180 in cooperation with each element of the medium conveyance device 100 based on a program stored in the storage device 170 in advance.

[0085] First, the control unit 181 waits until an instruction to read a medium is input by the user using the operation device 105 or the information processing device and an operation signal instructing the reading of the medium is received from the operation device 105 or the interface device 162 (step S101).

[0086] Next, the control unit 181 acquires a medium signal from the medium sensor 121 and determines whether a medium is placed on the mounting table 103 based on the acquired medium signal (step S102). If no medium is placed on the mounting table 103, the control unit 181 ends the series of steps.

[0087] On the other hand, if a medium is placed on the mounting table 103, the control unit 181 drives the first motor 132 and the second motor 161. Thereby, the control unit 181 rotates the first transport roller 111, the feed roller 122, the separation roller 123, the second transport roller 127, the third transport roller 128, the fourth transport roller 130, and / or the fifth transport roller 131 to transport the medium (step S103). Note that the control unit 181 controls the first motor 132 and the second motor 161 so that the moving speed of the surface of the first transport roller 111 is the same as the moving speed of the surface of the feed roller 122. Thereby, the control unit 181 can suppress the medium from being pushed downstream by the first transport roller 111 and causing a jam of the medium, and the medium from being pulled upstream by the first transport roller 111 and increasing the load on the medium.

[0088] Next, the determination unit 182 acquires a contact detection signal, a center signal, a first side signal, and a second side signal from the contact detection sensor 112, the center sensor 124, the first side sensor 125, and the second side sensor 126, respectively. The determination unit 182 stores each acquired signal in the storage device 170 in association with the acquired time (step S104).

[0089] Next, the determination unit 182 determines whether it has already identified whether skew has occurred in the medium currently being conveyed (step S105). If it has already identified whether skew has occurred in the medium currently being conveyed, the determination unit 182 transfers the process to step S110.

[0090] On the other hand, if it has not yet identified whether skew has occurred in the medium currently being conveyed, the determination unit 182 determines whether skew has occurred in the medium (step S106).

[0091] The determination unit 182 detects the passing times when the leading end of the medium passes the positions of the center sensor 124, the first side sensor 125, and the second side sensor 126 based on the center signal, the first side signal, and the second side signal. The determination unit 182 detects, as the passing time of the center sensor 124, the time when the signal value changes from a value indicating a state where the medium does not exist to a value indicating a state where the medium exists in each center signal acquired so far. Similarly, the determination unit 182 detects, as the passing time of the first side sensor 125, the time when the signal value changes from a value indicating a state where the medium does not exist to a value indicating a state where the medium exists in each first side signal acquired so far. Similarly, the determination unit 182 detects, as the passing time of the second side sensor 126, the time when the signal value changes from a value indicating a state where the medium does not exist to a value indicating a state where the medium exists in each second side signal acquired so far.

[0092] If each signal value has not yet changed from a value indicating a state where the medium does not exist to a value indicating a state where the medium exists, the determination unit 182 determines that the leading end of the medium has not yet passed the position of each sensor. If the leading end of the medium has not yet passed the position of any sensor, the determination unit 182 has not yet determined whether skew has occurred in the medium.

[0093] Next, based on the detected passing time, the determination unit 182 determines whether the leading end of the medium has passed the position of the first side sensor 125 or the position of the second side sensor 126 before passing the position of the center sensor 124.

[0094] When the leading end of the medium has passed the position of the first side sensor 125 or the second side sensor 126 first, the determination unit 182 calculates the difference time from the passing time of the side sensor that passed first to the passing time of the center sensor 124. When the leading end of the medium has not yet passed the position of the center sensor 124, the determination unit 182 calculates the elapsed time from the passing time of the side sensor that passed first to the present. When the difference time or the elapsed time is greater than the skew threshold, the determination unit 182 determines that skew of the medium has occurred. When the difference time is less than or equal to the skew threshold, the determination unit 182 determines that no skew of the medium has occurred. On the other hand, when the leading end of the medium has not yet passed the position of the center sensor 124 and the elapsed time is less than or equal to the skew threshold, the determination unit 182 has not yet determined whether skew of the medium has occurred.

[0095] That is, when the center sensor 124 does not detect the medium within the time of the skew threshold after any one of the first side sensor 125 and the second side sensor 126 detects the medium, the determination unit 182 determines that skew has occurred. The skew threshold is set to a value (for example, 1 second) between the difference time when the medium tilts and collides with the side wall of the conveyance path and the difference time when the medium does not collide with the side wall of the conveyance path through prior experiments. Note that the skew threshold may be set to 0. In that case, the determination unit 182 determines that skew has occurred when the medium is tilted and conveyed even slightly.

[0096] On the other hand, when the leading end of the medium has passed the position of the center sensor 124 first, the determination unit 182 decides not to determine whether skew of the medium has occurred.

[0097] FIG. 9(A) and (B) are schematic diagrams for explaining the skew of the medium. FIG. 9(A) shows an example in which the medium M1 is tilted and conveyed and first passes through the position of the first side sensor 125. FIG. 9(B) shows an example in which the medium M2 is tilted and conveyed and first passes through the position of the center sensor 124.

[0098] As shown in FIG. 9(A), when the medium M1 first passes through the position of the first side sensor 125, the determination unit 182 can specify that the medium M1 is tilted and conveyed toward the second side sensor 126. On the other hand, as shown in FIG. 9(B), when the medium M2 first passes through the position of the center sensor 124, the determination unit 182 cannot surely specify whether the direction in which the medium M2 is heading is the first side sensor 125 side or the second side sensor 126 side. When the center sensor 124 first detects the medium, the determination unit 182 does not determine whether the skew of the medium has occurred, thereby preventing the control unit 181 from erroneously correcting the skew of the medium.

[0099] When it is not determined by the determination unit 182 that the skew of the medium has occurred, the control unit 181 does not execute the correction of the skew of the medium (step S107) and transfers the process to step S110.

[0100] On the other hand, when the determination unit 182 determines that the skew of the medium has occurred, it determines whether the first transport rollers 111a and 111b are in contact with the medium being fed by the feed roller 122 (step S108).

[0101] The determination unit 182 determines whether each of the first transport rollers 111a and 111b is in contact with the medium being fed, based on, for example, the contact detection signals acquired from the respective contact detection sensors 112a and 112b. When the signal value of the contact detection signal changes from a value indicating that the arm is not in contact with the medium to a value indicating that the arm is in contact with the medium, the determination unit 182 determines that the trailing end of the medium has passed the position of the corresponding first transport roller 111. The determination unit 182 determines that each of the first transport rollers 111 is in contact with the medium being fed from the start of feeding of the medium until the trailing end of the medium passes the position of each first transport roller 111. On the other hand, after the trailing end of the medium has passed the position of each first transport roller 111, the determination unit 182 determines that each of the first transport rollers 111 is not in contact with the medium being fed.

[0102] The determination unit 182 may determine whether each of the first transport rollers 111a and 111b is in contact with the medium being fed by the feed roller 122, based on the center signal, the first side signal, and the second side signal. The determination unit 182 detects the passing times of the center sensor 124, the first side sensor 125, and the second side sensor 126 at the leading end of the medium, in the same manner as the process of step S106. When the difference between the passing time of the center sensor 124 and the passing time of one of the side sensors is equal to or less than the first threshold value and the difference between the passing time of the center sensor 124 and the passing time of the other side sensor is equal to or greater than the second threshold value, the determination unit 182 determines that the medium is being transported in a skewed manner. In this case, the determination unit 182 determines that the medium does not exist on the other side sensor in the width direction A2. The first threshold value is set to a sufficiently small time, and the second threshold value is set to a value greater than the first threshold value. When the determination unit 182 determines that the medium does not exist on any of the side sensors in the width direction A2, the determination unit 182 assumes that the medium also does not exist on the first transport roller 111 disposed on the side of that side sensor.

[0103] FIG. 10(A) is a schematic diagram for explaining the skew of the medium. FIG. 10(A) shows an example in which the medium M3 with a small width is placed closer to one side guide 114a.

[0104] As shown in FIG. 10(A), when the difference between the passing time of the center sensor 124 and the passing time of the first side sensor 125 is sufficiently small, it is highly likely that the medium M3 is not being conveyed while tilted. In that case, if the width of the medium M3 is sufficiently large, the difference between the passing time of the center sensor 124 and the passing time of the second side sensor 126 will also be sufficiently small. If the difference between the passing time of the center sensor 124 and the passing time of the second side sensor 126 is large despite the difference between the passing time of the center sensor 124 and the passing time of the first side sensor 125 being sufficiently small, it is highly likely that the medium is biased toward the side guide 114a. In this case, as shown in FIG. 10, it is highly likely that the medium does not contact the first conveying roller 111b disposed on the side opposite to the side guide 114a in the width direction A2.

[0105] Therefore, the determination unit 182 can accurately determine, based on the center signal, the first side signal, and the second side signal, whether each of the first conveying rollers 111a and 111b is in contact with the medium being fed by the feeding roller 122.

[0106] When it is determined that neither of the first conveying rollers 111a and 111b is in contact with the medium being fed by the feeding roller 122, the control unit 181 does not execute skew correction of the medium (step S107) and transfers the process to step S110. When the control unit 181 cannot correct the skew of the medium by the plurality of first conveying rollers 111, it can suppress the deterioration of the state of the medium by not executing the skew correction of the medium.

[0107] On the other hand, when it is determined that both of the first conveying rollers 111a and 111b are in contact with the medium being fed by the feeding roller 122, the control unit 181 executes skew correction of the medium (step S109).

[0108] The control unit 181 corrects the skew of the medium by making the peripheral speeds of the plurality of feed rollers 122a and 122b different from each other and the peripheral speeds of the plurality of first conveying rollers 111a and 111b different from each other for a predetermined time. In the width direction A2, the control unit 181 changes the peripheral speed of the feed roller 122 arranged on the side where the progress of the medium is delayed to be faster (higher) than the peripheral speed of the feed roller 122 arranged on the leading side. Also, in the width direction A2, the control unit 181 changes the peripheral speed of the first conveying roller 111 arranged on the side where the progress of the medium is delayed to be faster (higher) than the peripheral speed of the first conveying roller 111 arranged on the leading side. For example, the control unit 181 makes the peripheral speed of the roller arranged on the side where the progress of the medium is delayed faster than the peripheral speed when no skew of the medium occurs and / or makes the peripheral speed of the roller arranged on the leading side slower than the peripheral speed when no skew of the medium occurs. The control unit 181 sets each peripheral speed so that, for example, the peripheral speed of the roller arranged on the side where the progress of the medium is delayed is 3 times or more and 10 times or less the peripheral speed of the roller arranged on the leading side.

[0109] Further, the control unit 181 sets the peripheral speeds of the feed roller 122 and the first conveying roller 111 so that the moving speed of the surface of the feed roller 122 arranged on the same side in the width direction A2 is the same as the moving speed of the surface of the first conveying roller 111. That is, the control unit 181 sets the peripheral speed of each roller so that the moving speed of the surface of the feed roller 122a is the same as the moving speed of the surface of the first conveying roller 111a and the moving speed of the surface of the feed roller 122b is the same as the moving speed of the surface of the first conveying roller 111b. Thereby, the control unit 181 can suppress a non-uniform force from being applied to each position of the medium and the medium from being bent.

[0110] As shown in FIG. 9(A), when the medium M1 is fed while being inclined toward the second side sensor 126, the leading end of the medium M1 passes through the center sensor 124 after passing through the first side sensor 125. In that case, the greater the inclination of the medium M1, the longer the time from when it passes through the first side sensor 125 until it passes through the center sensor 124.

[0111] Therefore, when the leading end of the medium does not pass through the center sensor 124 within the skew threshold time from the passing time of the first side sensor 125, the control unit 181 determines that the medium is being conveyed while being inclined toward the second side sensor 126. In that case, the control unit 181 changes the peripheral speed of each feed roller 122 so that the peripheral speed of the feed roller 122b arranged on the second side sensor 126 side becomes faster than the peripheral speed of the feed roller 122a arranged on the first side sensor 125 side. As a result, the medium rotates toward the direction A21 of the first side sensor 125, and the skew of the medium is corrected. Further, the control unit 181 changes the peripheral speed of each first conveyance roller 111 so that the peripheral speed of the first conveyance roller 111b arranged on the second side sensor 126 side becomes faster than the peripheral speed of the first conveyance roller 111a arranged on the first side sensor 125 side. Thereby, the medium is assisted by the first conveyance roller 111 and smoothly rotates toward the direction A21 of the first side sensor 125, and the skew of the medium is corrected well.

[0112] Conversely, when the leading end of the medium does not pass through the center sensor 124 within the time of the skew threshold from the passing time of the second side sensor 126, the control unit 181 determines that the medium is being fed while tilted toward the first side sensor 125. In that case, the control unit 181 changes the peripheral speeds of the respective feed rollers 122 so that the peripheral speed of the feed roller 122a arranged on the first side sensor 125 side becomes faster than the peripheral speed of the feed roller 122b arranged on the second side sensor 126 side. Thereby, the medium rotates toward the second side sensor 126, and the skew of the medium is corrected. Further, the control unit 181 changes the peripheral speeds of the respective first transport rollers 111 so that the peripheral speed of the first transport roller 111a arranged on the first side sensor 125 side becomes faster than the peripheral speed of the first transport roller 111b arranged on the second side sensor 126 side. Thereby, the medium is assisted by the first transport roller 111 and rotates smoothly toward the second side sensor 126, and the skew of the medium is corrected well.

[0113] Note that the control unit 181 may set the respective peripheral speeds so that the difference in the peripheral speeds of the respective feed rollers 122 and the first transport rollers 111 becomes larger as the time from the passing time of the first side sensor 125 or the second side sensor 126 to the passing time of the center sensor 124 is larger. Thereby, the control unit 181 can correct the skew of the medium in a shorter time. Further, the control unit 181 may set the peripheral speeds of the feed rollers 122 and the first transport rollers 111 arranged on the leading side to 0. Thereby, in the width direction A2, the medium portion on the trailing side can be advanced while keeping the medium portion on the leading side at that position, so that the skew of the medium can be corrected more reliably. Alternatively, the control unit 181 may set the peripheral speeds of both of the plurality of feed rollers 122 and the peripheral speeds of both of the plurality of first transport rollers 111 to values greater than 0 and different from each other. Thereby, the control unit 181 can transport the medium while correcting the skew of the medium, so that the medium can be transported in a shorter time.

[0114] In this way, when the determination unit 182 determines that skew of the medium has occurred, the control unit 181 controls the plurality of first conveyance rollers 111 together with the plurality of feed rollers 122 to correct the skew of the medium being fed. The control unit 181 corrects the skew of the medium being fed using at least one of the plurality of first conveyance rollers 111a and 111b. Thereby, the control unit 181 can appropriately correct the skew of the medium. Note that the control unit 181 may correct the skew of the medium by making only the peripheral speeds of the plurality of first conveyance rollers 111a and 111b different from each other without making the peripheral speeds of the plurality of feed rollers 122a and 122b different from each other. Also in that case, the control unit 181 can correct the skew of the medium.

[0115] Next, in the same manner as the process of step S108, the determination unit 182 determines whether or not the medium being fed is in contact with the first conveyance rollers 111a and 111b and the feed rollers 122 (step S110). When it is determined that both of the first conveyance rollers 111a and 111b and the medium being fed are in contact, the control unit 181 does not execute any particular process and proceeds to step S112.

[0116] On the other hand, when it is determined that either one of the first conveyance rollers 111a and 111b is not in contact with the medium being fed, the control unit 181 stops the rotation of the first conveyance roller 111 that is not in contact with the medium being fed (step S111). The control unit 181 controls the first motor 132 that rotates the first conveyance roller 111 so as to stop the rotation of the first conveyance roller 111 that is not in contact with the medium being fed. For example, the control unit 181 stops the rotation of the first conveyance roller 111 by turning off the power supply of the corresponding first motor 132. Note that the control unit 181 may excite the corresponding first motor 132 so as to lock the first conveyance roller 111. Thereby, the control unit 181 can more reliably stop the first conveyance roller 111.

[0117] FIG. 10(B) is a schematic diagram for explaining the contact between the first conveying roller 111 and the medium being fed. FIG. 10(B) shows an example in which a plurality of media M4 and M5 are collectively placed on the mounting table 103 and are fed in the order of the medium M4 and the medium M5.

[0118] As shown in FIG. 10(B), after the rear end of the medium M4 being fed passes the position of the first conveying roller 111, the first conveying roller 111 contacts the next medium M5 to be fed. The leading end of the next medium M5 to be fed is stopped by the separating roller 123 and does not move until the rear end of the medium M4 being fed passes the positions of the feeding roller 122 and the separating roller 123. In this state, when the first conveying roller 111 attempts to convey the medium M5, the medium M5 will bend, and there is a possibility that skew or jam of the medium will occur during the feeding of the medium M5. Also, as in the case of the medium M3 shown in FIG. 10(A), when the medium being fed is in contact with only one of the first conveying rollers 111, only the other first conveying roller 111 contacts the next medium to be fed. If only the other first conveying roller 111 attempts to convey the next medium to be fed, the medium will tilt, and there is a possibility that skew or jam of the medium will occur during the feeding of the medium. Also, there is a possibility that double feeding of the medium will occur when the next medium to be fed is pushed out by the first conveying roller 111b.

[0119] The control unit 181 controls the first motor 132 so as not to rotate the first conveying roller 111 that is not in contact with the medium being fed by the feeding roller 122. Thereby, the control unit 181 can suppress the occurrence of skew, jam, or double feeding of the next medium to be fed during the feeding of the medium.

[0120] Next, the control unit 181 determines whether the rear end of the medium has passed through the imaging position by the imaging device 129 (step S112). The control unit 181 determines that the rear end of the medium has passed through the imaging position by the imaging device 129 when the second predetermined time has elapsed since the rear end of the medium passed through the position of the center sensor 124. The second predetermined time is set to a time obtained by adding a margin to the time required for the medium to move from the position of the center sensor 124 to the imaging position. Note that the control unit 181 may determine that the rear end of the medium has passed through the imaging position by the imaging device 129 when the third predetermined time has elapsed since the start of feeding the medium. If the rear end of the medium has not yet passed through the imaging position by the imaging device 129, the control unit 181 returns the process to step S104 and repeats the processes of steps S104 to S111.

[0121] On the other hand, when the rear end of the medium has passed through the imaging position by the imaging device 129, the control unit 181 acquires an input image from the imaging device 129 and outputs it by transmitting it to the information processing device via the interface device 162 (step S113).

[0122] Next, the control unit 181 determines whether there is any medium remaining on the mounting table 103 based on the medium signal received from the medium sensor 121 (step S114). If there is any medium remaining on the mounting table 103, the control unit 181 returns the process to step S104 and repeats the processes of steps S104 to S113.

[0123] On the other hand, if there is no medium remaining on the mounting table 103, the control unit 181 stops the first motor 132 and the second motor 161. Thereby, the control unit 181 stops the first conveying roller 111, the feeding roller 122, the separating roller 123, the second conveying roller 127, the third conveying roller 128, the fourth conveying roller 130, and the fifth conveying roller 131 (step S115), and ends a series of steps.

[0124] Note that the process of step S108 and / or the processes of steps S110 to S111 may be omitted.

[0125] As described in detail above, in the medium conveyance device 100, in order to correct the skew of the medium, a plurality of first conveyance rollers 111 that rotate independently by the driving force from the first motor 132 are provided on the mounting table 103. Even when a large amount of media is placed on the mounting table 103, the medium conveyance device 100 can apply sufficient conveyance force to the fed medium by the first conveyance rollers 111 and feed the medium well. Thereby, the medium conveyance device 100 can apply sufficient conveyance force to the fed medium regardless of the amount of the medium. Further, when the skew of the medium occurs, the medium conveyance device 100 can appropriately assist in correcting the skew of the medium by the first conveyance rollers 111. Therefore, the medium conveyance device 100 has become capable of stably conveying a large amount of media and appropriately correcting the skew of the medium when the skew of the medium occurs.

[0126] Generally, considering the working efficiency of the user, it is desirable for the medium conveyance device to continuously convey and read as large an amount of media as possible. However, when a large amount of media is placed on the mounting table, the weight of the media placed on the upper side is applied to the medium to be fed at the lowermost side, so the conveyance performance of the media deteriorates and the skew of the media may occur. Since the medium conveyance device 100 stably conveys a large amount of media and appropriately corrects the skew of the media when the skew occurs, the user can place a large amount of media on the mounting table 103 at once and have the medium conveyance device 100 execute the medium reading process. Therefore, the medium conveyance device 100 has become capable of improving the working efficiency of the user and improving the convenience of the user.

[0127] In addition, even when a slippery medium such as a card or glossy paper is placed on the medium conveyance device 100, the first conveyance roller 111 can apply sufficient conveyance force to the conveyed medium, enabling the medium to be fed properly. As a result, the medium conveyance device 100 can apply sufficient conveyance force to the conveyed medium regardless of the type of the medium. Therefore, the medium conveyance device 100 can stably convey various types of media and, when skew of the medium occurs, can appropriately correct the skew of the medium.

[0128] Note that the first conveyance roller 111 may be a driven roller that rotates in a driven manner with respect to the conveyed medium. Even in that case, the first conveyance roller 111 can suppress the rotation of the medium when skew of the medium is about to occur while applying conveyance force to the medium. Therefore, the medium conveyance device 100 can stably convey a large amount of media and, when skew of the medium occurs, can appropriately correct the skew of the medium.

[0129] FIG. 11(A) is a schematic diagram for explaining the contact detection sensors 212a and 212b of the medium conveyance device 200 according to another embodiment.

[0130] The medium conveyance device 200 has each part that the medium conveyance device 100 has. However, the medium conveyance device 200 has a plurality of contact detection sensors 212a and 212b instead of the plurality of contact detection sensors 112a and 112b. Hereinafter, the contact detection sensors 212a and 212b may be referred to as the contact detection sensor 212.

[0131] The plurality of contact detection sensors 212a and 212b are arranged side by side on the mounting table 103 downstream of the first conveying roller 111 in the medium conveying direction A1 and at intervals in the width direction A2. The contact detection sensor 212 is an optical sensor having a light emitter and a light receiver provided in the mounting table 103, and detects the movement of the medium in the medium conveying direction A1 and the width direction A2. The light emitter is, for example, an LED or the like, and emits light toward the medium placed on the mounting table 103 from the mounting surface 103a. The light receiver captures an image corresponding to the light received at regular intervals, and detects a common portion from the latest image and the immediately preceding image. Based on the change in the position of the detected common portion within the image, the light receiver calculates the moving speed of the medium in the medium conveying direction A1 and the width direction A2, and generates and outputs a contact detection signal indicating the calculated moving speed. The regular interval is, for example, a period corresponding to 100 operation pulses of the first motor 132. The light receiver has a resolution of, for example, 400 dpi (Dots Per inch) and is provided so as to be able to detect a movement of up to 304.8 mm per second. A known optical sensor can be used as the contact detection sensor 212.

[0132] Similar to the medium conveying device 100, the medium conveying device 200 executes the medium reading process shown in FIG. 8. However, in steps S108 and S110, the determination unit 182 determines whether or not each of the first conveying rollers 111a and 111b is in contact with the medium being fed by the feeding roller 122 based on the contact detection signals acquired from the respective contact detection sensors 212a and 212b.

[0133] When the difference in the moving speed in the medium conveyance direction A1 in each contact detection signal acquired from each contact detection sensor 212 is equal to or greater than a predetermined difference, the determination unit 182 determines that each contact detection sensor 212 is facing a separate medium. In that case, the determination unit 182 determines that the first conveyance roller 111 disposed on the side of the contact detection sensor 212 with the lower moving speed in the medium conveyance direction A1 is not in contact with the medium being fed, but is in contact with the medium disposed above the medium being fed. Note that when the difference in the moving speed in the width direction A2 in each contact detection signal acquired from each contact detection sensor 212 is equal to or greater than a predetermined difference, the determination unit 182 may determine that each contact detection sensor 212 is facing a separate medium. In that case, the determination unit 182 determines that the first conveyance roller 111 disposed on the side of the contact detection sensor 212 with the higher moving speed in the width direction A2 is not in contact with the medium being fed, but is in contact with the medium disposed above the medium being fed.

[0134] In the example shown in FIG. 11(A), a medium M7 having a larger width is disposed on a medium M6 having a smaller width on the mounting table 103, and the medium M6 is closer to one side guide 114a. In this case, the medium M6 is fed toward the downstream side, but the medium M7 remains without being fed. Therefore, the moving speed in the medium conveyance direction A1 detected by the contact detection sensor 212b facing the medium M7 is lower than the moving speed in the medium conveyance direction A1 detected by the contact detection sensor 212a facing the medium M6. Further, since a conveying force is applied to the medium M7 that remains without being fed from the first conveyance roller 111b, the medium M7 tilts slightly. Therefore, the moving speed in the width direction A2 detected by the contact detection sensor 212b facing the medium M7 is higher than the moving speed in the width direction A2 detected by the contact detection sensor 212a facing the medium M6.

[0135] Therefore, the determination unit 182 can accurately determine whether or not each first conveyance roller 111a, 111b is in contact with the medium being fed based on the contact detection signals acquired from the contact detection sensors 212a, 212b.

[0136] Also, in the placement table 103, when the contact detection sensor 212, which is an optical sensor, is provided in the medium transport device 200, the determination unit 182 may determine whether or not skew of the medium has occurred based on the contact detection signal from the contact detection sensor 212. In that case, the determination unit 182 periodically receives the contact detection signal from the contact detection sensor 212, and determines that skew of the medium has occurred when the moving speed of the medium in the width direction A2 indicated by the signal value of the contact detection signal is equal to or higher than a predetermined speed. Since the medium transport device 200 determines whether or not skew of the medium has occurred using the contact detection sensor 212 disposed on the placement table 103, the skew of the medium can be corrected at an early stage. In particular, since the medium transport device 200 can correct the skew of the medium before the medium is strongly sandwiched by the feed roller 122 and the separation roller 123, the skew of the medium can be corrected better, and the occurrence of wrinkles in the medium such as thin paper can be suppressed.

[0137] Also, in the medium transport device 200, instead of the contact detection sensor 212, a contact detection sensor may be provided on the central side (inner side) surface in the width direction A2 of the side guides 114a and 114b. Each contact detection sensor generates and outputs a contact detection signal whose signal value changes between a state where the medium is in contact with each of the side guides 114a and 114b and a state where the medium is not in contact. The determination unit 182 periodically receives the contact detection signal from each contact detection sensor. When the signal value of the contact detection signal received from one contact detection sensor indicates that the medium is in contact, and the signal value of the contact detection signal received from the other contact detection sensor indicates that the medium is not in contact, the determination unit 182 determines that the medium is placed on one side reference. When the medium transport device 200 determines that the medium is placed on one side reference, it assumes that the first transport roller 111 disposed on the side guide 114 side where the medium is not in contact and the medium being fed are not in contact.

[0138] Also, the determination unit 182 may receive from the user whether or not the medium is placed on one side reference using the operation device 105.

[0139] As described in detail above, even when the medium conveyance device 200 determines the contact between the first conveyance roller 111 and the medium being fed using the optical sensor, while stably conveying a large amount of media, if skew of the media occurs, the skew of the media can be appropriately corrected.

[0140] FIG. 11(B) is a schematic diagram for explaining the contact detection sensors 312a and 312b of the medium conveyance device 300 according to still another embodiment.

[0141] The medium conveyance device 300 has each part that the medium conveyance device 200 has. However, instead of the plurality of contact detection sensors 212a and 212b, the medium conveyance device 200 has a plurality of contact detection sensors 312a and 312b. Hereinafter, the contact detection sensors 312a and 312b may be referred to as the contact detection sensor 312.

[0142] The plurality of contact detection sensors 312a and 312b are arranged side by side on the mounting table 103 at the center in the width direction A2, for example, between the plurality of feed rollers 122 and at intervals in the medium conveyance direction A1. The contact detection sensor 312a arranged on the upstream side is preferably arranged so as to overlap the first conveyance rollers 111a and 111b in the medium conveyance direction A1, that is, as viewed from the width direction A2. The contact detection sensor 312 is the same optical sensor as the contact detection sensor 212, and generates and outputs a contact detection signal indicating the moving speed of the medium in the medium conveyance direction A1 and the width direction A2.

[0143] Similar to the medium conveyance device 200, the medium conveyance device 300 executes the medium reading process shown in FIG. 8. However, in steps S108 and S110, the determination unit 182 determines whether or not each of the first conveyance rollers 111a and 111b is in contact with the medium being fed by the feed roller 122 based on the contact detection signals acquired from the respective contact detection sensors 312a and 312b.

[0144] When the difference in the moving speed in the medium conveyance direction A1 in each contact detection signal acquired from each contact detection sensor 312 is equal to or greater than a predetermined difference, the determination unit 182 determines that each contact detection sensor 312 is facing a separate medium. In particular, when the moving speed detected by the upstream contact detection sensor 312a is lower than the moving speed detected by the downstream contact detection sensor 312b, the determination unit 182 determines that each contact detection sensor 312 is facing a separate medium. In that case, the determination unit 182 determines that neither of the first conveyance rollers 111a and 111b is in contact with the medium being fed, and is in contact with the medium placed on the medium being fed.

[0145] In the example shown in FIG. 11(B), a plurality of media M8 and M9 are collectively placed on the mounting table 103 and fed in the order of the medium M8 and the medium M9. In this case, after the rear end of the medium M8 being fed passes the position of the first conveyance roller 111, the next medium M9 to be fed comes into contact with the first conveyance roller 111. This medium M9 remains in a slightly deflected state without being fed. Therefore, the moving speed in the medium conveyance direction A1 detected by the upstream contact detection sensor 312a facing the medium M9 is smaller than the moving speed in the medium conveyance direction A1 detected by the downstream contact detection sensor 312b facing the medium M8.

[0146] Therefore, based on the contact detection signals acquired from the contact detection sensors 312a and 312b, the determination unit 182 can accurately determine whether or not the first conveyance roller 111 is in contact with the medium being fed.

[0147] Note that the medium conveyance device 300 may determine whether or not skew of the medium has occurred based on the contact detection signal from the contact detection sensor 312 in the same manner as the medium conveyance device 200.

[0148] As described in detail above, even when the optical sensors are arranged side by side along the medium conveyance direction A1, the medium conveyance device 300 can stably convey a large number of media and appropriately correct the skew of the medium when the skew of the medium occurs.

[0149] FIG. 12 is a schematic diagram for explaining first transmission mechanisms 440a and 440b of a medium transport device 400 according to still another embodiment.

[0150] The medium transport device 400 has each part that the medium transport devices 100, 200, or 300 has. However, in the medium transport device 400, one of the plurality of first motors 132a and 132b is omitted. Hereinafter, the case where the first motor 132b is omitted will be described. Further, the medium transport device 400 has a plurality of first transmission mechanisms 440a and 440b instead of the plurality of first transmission mechanisms 140a and 140b. Hereinafter, the first transmission mechanisms 440a and 440b may be referred to as the first transmission mechanism 440.

[0151] The first transmission mechanisms 440a and 440b each have each part that the first transmission mechanisms 140a and 140b have. However, in the first transmission mechanisms 440a and 440b, the first belt 141b on the side of the omitted first motor 132b is omitted, and the first gear 142b on the side of the omitted first motor 132b does not have a pulley portion. Further, the first transmission mechanisms 440a and 440b further have second shafts 446, electromagnetic clutches 447a and 447b, and third shafts 448a and 448b. Hereinafter, the electromagnetic clutches 447a and 447b may be referred to as the electromagnetic clutch 447.

[0152] The second shaft 446 is provided between the first gear 142a and the first gear 142b so that the first gear 142b rotates as the first gear 142a rotates. The first gears 142a and 142b are engaged with the electromagnetic clutches 447a and 447b, respectively. The electromagnetic clutches 447a and 447b are respectively attached to the third shafts 448a and 448b, and second gears 143a and 143b are respectively attached to the third shafts 448a and 448b.

[0153] The electromagnetic clutch 447 is a clutch capable of electromagnetically changing the torque limit value according to a control signal from the processing circuit 180, and transmits the driving force from the first motor 132a to the first carrier rollers 111a and 111b. The electromagnetic clutch 447 is, for example, a micropowder clutch. The electromagnetic clutch 447 may be another type of clutch such as a hysteresis clutch.

[0154] In the first transmission mechanism 440, when the first motor 132a generates a driving force, the first belt 141a rotates in the direction of arrow A11. Accordingly, the first gear 142a rotates in the direction of arrow A12, and the first gear 142b rotates in the direction of arrow A12 via the second shaft 446. Further, with the rotation of the first gears 142a and 142b, the electromagnetic clutches 447a and 447b rotate in the direction of arrow A13, respectively, and the second gears 143a and 143b rotate in the direction of arrow A13 via the third shafts 448a and 448b, respectively.

[0155] Similar to the media transport devices 100, 200, or 300, the media transport device 400 executes the media reading process shown in FIG. 8. However, in step S109, the control unit 181 corrects the skew of the media by stopping the rotation of either one of the plurality of first carrier rollers 111a and 111b. The control unit 181 controls the electromagnetic clutch 447 arranged on the leading side so that the driving force from the first motor 132a is not transmitted to the first carrier roller 111 arranged on the leading side in the width direction A2.

[0156] The media transport device 400 can reduce the number of motors by driving the plurality of first carrier rollers 111 with one first motor 132a, and can reduce the device cost and the device size.

[0157] As described in detail above, even when the media transport device 400 drives the plurality of first carrier rollers 111 with one first motor 132a, it is possible to stably transport a large amount of media and appropriately correct the skew of the media when the skew of the media occurs.

[0158] FIG. 13 is a schematic diagram for explaining first transmission mechanisms 540a and 540b of a medium transport device 500 according to still another embodiment.

[0159] The medium transport device 500 has each part that the medium transport devices 100, 200, or 300 has. However, the medium transport device 500 has a plurality of first transmission mechanisms 540a and 540b instead of the plurality of first transmission mechanisms 140a and 140b. Hereinafter, the first transmission mechanisms 540a and 540b may be referred to as the first transmission mechanism 540.

[0160] The first transmission mechanisms 540a and 540b each have each part that the first transmission mechanisms 140a and 140b have. However, the first transmission mechanisms 540a and 540b further have fourth shafts 549a and 549b.

[0161] The fourth shaft 549a is provided between the third gear 144a and the feed roller 122a so that the feed roller 122a rotates as the third gear 144a rotates. Thereby, the first transmission mechanism 140a transmits the driving force from the first motor 132a to the first transport roller 111a and also to the feed roller 122a. Similarly, the fourth shaft 549b is provided between the third gear 144b and the feed roller 122b so that the feed roller 122b rotates as the third gear 144b rotates. Thereby, the first transmission mechanism 140b transmits the driving force from the first motor 132b to the first transport roller 111b and also to the feed roller 122b. That is, the first motors 132a and 132b generate a driving force for rotating the feed rollers 122a and 122b in addition to the first transport rollers 111a and 111b, respectively.

[0162] In the first transmission mechanism 540, when the third gears 144a and 144b rotate in the direction of arrow A14, the feed rollers 122a and 122b rotate in the medium feed direction A14 via the fourth shafts 549a and 549b.

[0163] Thus, the first conveying roller 111 and the feeding roller 122 are provided to rotate by the driving force from the first motor 132. By sharing the motor between the first conveying roller 111 and the feeding roller 122, the medium conveying device 500 can reduce the number of motors, and can reduce the device cost and the device size.

[0164] Note that, similar to the medium conveying device 400, the medium conveying device 500 may drive a plurality of first conveying rollers 111 and a plurality of feeding rollers 122 with one first motor 132a. In that case, in the medium conveying device 500, one of the plurality of first motors 132a and 132b is omitted, and instead, a second shaft for transmitting the driving force between the first gear 142a and the first gear 142b is provided. Further, in the medium conveying device 500, an electromagnetic clutch for switching ON / OFF of the transmission of the driving force between the first gears 142a and 142b and the second gears 143a and 143b is provided. Thereby, the medium conveying device 500 can further reduce the number of motors, and can reduce the device cost and the device size.

[0165] As described in detail above, when the medium conveying device 500 drives the first conveying roller 111 and the feeding roller 122 with the common first motor 132, it is possible to stably convey a large amount of media and appropriately correct the skew of the media when the skew of the media occurs.

[0166] FIG. 14 is a schematic diagram for explaining the first conveying rollers 611a and 611b of a medium conveying device 600 according to still another embodiment.

[0167] The media conveyance device 600 has each part that the media conveyance devices 100, 200, 300, 400, or 500 have. However, instead of the plurality of first conveyance rollers 111a, 111b and the plurality of contact detection sensors 112a, 112b, the media conveyance device 600 has a plurality of first conveyance rollers 611a, 611b and a plurality of contact detection sensors 612a, 612b. Hereinafter, the first conveyance rollers 611a, 611b and the contact detection sensors 612a, 612b may be referred to as the first conveyance rollers 611 and the contact detection sensors 612.

[0168] The first conveyance roller 611 has the same structure and function as the first conveyance roller 111. However, the first conveyance roller 611 is arranged at the upstream end of the mounting table 103 in the media conveyance direction A1. Also, the first conveyance roller 611 is arranged so as to overlap with the first extension tray 103b when viewed from the media conveyance direction A1, that is, in the width direction A2. That is, the first conveyance roller 611 is arranged around the downstream end of the first extension tray 103b.

[0169] The plurality of contact detection sensors 612a, 612b are arranged downstream of the first conveyance roller 611 in the media conveyance direction A1 and overlap with the corresponding first conveyance rollers 611a, 611b when viewed from the media conveyance direction A1, that is, in the width direction A2. The contact detection sensor 612 has the same configuration as the contact detection sensor 112. In the media conveyance device 600, the above-described contact detection sensor 212 or 312 may be provided instead of the contact detection sensor 612.

[0170] FIG. 15 is a schematic diagram showing the media M10 placed on the mounting table 103 of the media conveyance device 600. FIG. 15 is a schematic diagram of the periphery of the mounting table 103 viewed from the side.

[0171] As described above, the first extension tray 103b is provided so as to be pullable upstream in the medium conveyance direction A1 from the mounting table 103. Therefore, as shown in FIG. 15, a step is formed between the mounting surface 103a of the mounting table 103 and the mounting surface 103e of the first extension tray 103b. Since the first conveyance roller 611 is disposed at the upstream end of the mounting table 103 where the step is formed, the contact area between the first conveyance roller 611 and the medium M10 placed on the mounting table 103 increases by the amount of the step. Therefore, the medium conveyance device 600 can increase the apparent coefficient of friction between the first conveyance roller 611 and the medium M10 placed on the mounting table 103, and can efficiently apply a conveyance force to the medium M10.

[0172] As described in detail above, the medium conveyance device 600 can stably convey a large amount of media even when the first conveyance roller 611 is disposed at the upstream end of the mounting table 103, and can appropriately correct the skew of the media when the skew of the media occurs.

[0173] FIG. 16 is a schematic diagram for explaining the second transmission mechanisms 750a and 750b of a medium conveyance device 700 according to still another embodiment.

[0174] The medium conveyance device 700 has each part that the medium conveyance devices 100, 200, 300, 400, 500, or 600 has. However, the medium conveyance device 700 has second transmission mechanisms 750a and 750b instead of the second transmission mechanisms 150a and 150b.

[0175] The second transmission mechanisms 750a and 750b have each part that the second transmission mechanisms 150a and 150b have. However, the second transmission mechanisms 750a and 750b have pulleys 753a and 753b and first shafts 754a and 754b instead of the pulleys 153a and 153b and the first shafts 154a and 154b. The second transmission mechanisms 750a and 750b further have fifth shafts 756a and 756b, support members 757a and 757b, and elastic members 758a and 758b.

[0176] The fifth shafts 756a and 756b are respectively disposed between the pulleys 753a and 753b and the first shafts 754a and 754b. Both ends of the fifth shafts 756a and 756b and the receiving portions provided on the pulleys 753a and 753b and the first shafts 754a and 754b have a universal joint structure. Thereby, the fifth shafts 756a and 756b are respectively tiltably connected to the pulleys 753a and 753b, rotate following the rotation of the pulleys 753a and 753b, and rotate the first shafts 754a and 754b.

[0177] The support members 757a and 757b are provided such that their upper ends support the first shafts 754a and 754b and their lower ends are attached to the upper ends of the elastic members 758a and 758b.

[0178] The elastic members 758a and 758b are spring members such as screw recoil springs. Note that the elastic members 758a and 758b may be other spring members such as leaf springs or rubber members. The elastic members 758a and 758b are respectively provided such that their upper ends are attached to the lower ends of the support members 757a and 757b and their lower ends are fixed to the bottom surface of the mounting table 103 or the like. The elastic members 758a and 758b generate a pressing force that presses the first shafts 754a and 754b upward via the support members 757a and 757b. Thereby, the elastic members 758a and 758b respectively press a plurality of first conveyance rollers 111a and 111b attached to the first shafts 754a and 754b toward the medium side mounted on the mounting table 103.

[0179] FIG. 17(A) is a schematic diagram showing a state in which a large amount of medium group M11 is placed on the mounting table 103 of the medium conveyance device 700, and FIG. 17(B) is a schematic diagram showing a state in which a small amount of medium group M12 is placed on the mounting table 103 of the medium conveyance device 700. FIGS. 17(A) and (B) are schematic diagrams of the periphery of the mounting table 103 viewed from the side.

[0180] As shown in FIG. 17(A), when a large amount of media group M11 is placed on the placement table 103, due to the weight of the media group M11, the elastic members 758a and 758b are pressed, and the first transport roller 111 sinks. In this case, among the media group M11, the lowermost media is pressed by the media arranged on the upper side, so the apparent coefficient of friction between the first transport roller 111 and the lowermost media increases.

[0181] On the other hand, as shown in FIG. 17(B), when a small amount of media group M12 is placed on the placement table 103, among the media group M12, the pressing force that the lowermost media is pressed toward the first transport roller 111 by the weight of the media arranged on the upper side is small. In this case, the elastic members 758a and 758b are not strongly pressed by the weight of the media group M12, and the first transport roller 111 does not sink. Therefore, the contact area between the lowermost media among the media group M12 and the first transport roller 111 increases. Thus, the media transport device 700 can increase the apparent coefficient of friction between the first transport roller 111 and the lowermost media.

[0182] That is, the media transport device 700 can apply an appropriate amount of transport force to the lowermost media whether the amount of media placed on the placement table 103 is large or small.

[0183] As described in detail above, even when the media transport device 700 has the elastic members 758a and 758b that press the first transport roller 111 toward the media side, it is possible to stably transport a large amount of media and appropriately correct the skew of the media when the skew of the media occurs.

[0184] FIG. 18 is a diagram showing a schematic configuration of a processing circuit 880 in a medium transport apparatus according to still another embodiment. The processing circuit 880 is used in place of the processing circuit 180 of the medium transport apparatus 100, and executes medium reading processing and the like in place of the processing circuit 180. The processing circuit 880 includes a control circuit 881, a determination circuit 882, and the like. Note that each of these units may be configured by an independent integrated circuit, microprocessor, firmware, or the like.

[0185] The control circuit 881 is an example of a control unit and has the same functions as the control unit 181. The control circuit 881 receives an operation signal from the operation device 105 or the interface device 162, a medium signal from the medium sensor 121, and a center signal from the center sensor 124. The control circuit 881 controls the first motor 132 and the second motor 161 based on each received piece of information, acquires an input image from the imaging device 129, and outputs it to the interface device 162. The control circuit 881 reads the determination result of the skew of the medium and the contact between the first transport roller 111 and the medium from the storage device 170, and controls the first motor 132, the second motor 161, and / or the electromagnetic clutch 447 to correct the skew of the medium based on the read determination result.

[0186] The determination circuit 882 is an example of a determination unit and has the same functions as the determination unit 182. The determination circuit 882 receives a center signal from the center sensor 124, a first side signal from the first side sensor 125, a second side signal from the second side sensor 126, and a contact detection signal from the contact detection sensors 112, 212, 312, or 612. The determination circuit 882 determines whether or not the skew of the medium has occurred and whether or not the first transport roller 111 is in contact with the medium based on each received signal, and stores the determination result in the storage device 170.

[0187] As described in detail above, even when the processing circuit 880 is used, the medium transport apparatus can stably transport a large amount of media and appropriately correct the skew of the medium when the skew of the medium occurs.

Description of Reference Numerals

[0188] 100, 200, 300, 400, 500, 600 Media conveying device 101 Lower housing 103 Placing table 103b First extension tray 111, 611 First conveying roller 112, 212, 312, 612 Contact detection sensor 113 Driven roller 122 Feeding roller 123 Separating roller 132 First motor 140, 440, 540 First transmission mechanism 150, 750 Second transmission mechanism 181 Control unit 182 Judgment unit 758a, 758b Elastic member

Claims

1. A mounting table, a feeding roller for feeding a medium placed on the mounting table, a separating roller arranged to face the feeding roller, a motor for generating a driving force, a plurality of conveying rollers arranged on the mounting table upstream of the feeding roller and the separating roller in the medium conveying direction and spaced apart in a direction orthogonal to the medium conveying direction, and independently rotating by the driving force to convey the medium, a one-way clutch for preventing reverse rotation of the conveying roller, a determination unit for determining whether skew of the medium has occurred, a control unit for controlling the plurality of conveying rollers to correct the skew of the medium being fed when it is determined that skew of the medium has occurred, A medium conveying device, characterized by comprising the above components.

2. The medium conveying device according to claim 1, wherein the rotation axes of the plurality of conveying rollers are arranged on the same straight line.

3. The medium conveying device according to claim 1 or 2, wherein the plurality of conveying rollers are arranged outside the feeding roller and the separating roller in a direction orthogonal to the medium conveying direction.

4. The medium conveying device according to any one of claims 1 to 3, wherein the feeding roller is provided to rotate by the driving force.

5. A housing in which the motor is arranged, a first transmission part provided on the housing, connected to the motor, and transmitting the driving force, a second transmission part provided on the mounting table, connected to the first transmission part, and transmitting the driving force transmitted by the first transmission part to the plurality of conveying rollers, and further comprising, The medium conveying device according to any one of claims 1 to 4, wherein the mounting table is detachably provided on the housing.

6. The medium conveying device according to any one of claims 1 to 5, further comprising a driven roller arranged between the plurality of conveying rollers and the feeding roller and the separating roller in the medium conveying direction and rotating following the fed medium.

7. The medium conveying device according to any one of claims 1 to 6, further comprising an elastic member for pressing the plurality of conveying rollers against the medium placed on the mounting table.

8. The medium conveying device according to any one of claims 1 to 7, further comprising a sensor for detecting contact between each of the plurality of conveying rollers and the medium being fed by the feeding roller, wherein the control unit controls not to rotate the conveying roller that is not in contact with the medium being fed by the feeding roller.

9. Further comprising an extension tray that is provided so as to be pullable upstream in the medium conveyance direction from the placement table, The plurality of conveyance rollers are arranged at an end portion upstream of the placement table in the medium conveyance direction, and the medium conveyance device according to any one of claims 1 to 8.

10. A control method for a medium conveyance device, comprising: Feeding the medium placed on the placement table by a feeding roller, Generating a driving force by a motor, On the placement table, a plurality of conveyance rollers are arranged at intervals in a direction orthogonal to the medium conveyance direction and upstream of the feeding roller and the separation roller arranged opposite to the feeding roller in the medium conveyance direction, and the medium is conveyed by independently rotating each of them by the driving force, Determining whether skew of the medium has occurred, When it is determined that skew of the medium has occurred, controlling the plurality of conveyance rollers to correct the skew of the medium being fed, Preventing reverse rotation of the conveyance roller by a one-way clutch, A control method characterized by the above.

11. A control program for a medium conveyance device having a placement table, a feeding roller for feeding the medium placed on the placement table, a separation roller arranged opposite to the feeding roller, a motor for generating a driving force, and a plurality of conveyance rollers arranged on the placement table at intervals in a direction orthogonal to the medium conveyance direction and upstream of the feeding roller and the separation roller, and independently rotating by the driving force to convey the medium, and a one-way clutch for preventing reverse rotation of the conveyance roller, comprising: Determining whether skew of the medium has occurred, When it is determined that skew of the medium has occurred, controlling the plurality of conveyance rollers to correct the skew of the medium being fed, A control program characterized by causing the medium conveyance device to execute the above.

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