Medium transport device, medium transport method and controlling program

Abstract

To provide a medium transport device capable of more appropriately recovering a medium when a duplicated medium is fed.SOLUTION: The medium transport device includes: a mounting table; a feed roller for feeding a medium placed on the mounting table; a separation roller arranged opposite the feed roller; a first motor for driving the feed roller, a second motor for driving the separation roller; a determination unit for determining whether or not a double feed of media has occurred; and a control unit for controlling the first motor and the second motor to return the medium to the mounting table when the determination unit determines that a double feed of media has occurred, the control unit controlling the first motor and the second motor to rotate the separation roller and then the feed roller when returning the medium to the mounting table.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present disclosure relates to a medium conveyance device, a medium feeding method, and a control program.

Background Art

[0002] In a medium conveyance device such as a scanner that sequentially feeds and images while separating a plurality of media, when double feeding of the media occurs, the user needs to take out the media from the housing and reset it on the mounting table. In a medium conveyance device, in order to improve the convenience for the user, it is desired to automatically recover the media to the mounting table when double feeding of the media occurs.

[0003] A paper feeding device is disclosed that includes a conveyance roller, a shaft that is connected to the conveyance roller via a one-way clutch structure and rotates in a first direction and a second direction by the driving force of a first drive motor, and a separation roller to which the driving force of a second drive motor is transmitted (see Patent Document 1). This paper feeding device has a first mode in which the shaft is rotated in the first direction to rotate the conveyance roller in the first direction, and a second mode in which the shaft is rotated in the second direction to release the restriction on the rotation of the conveyance roller in the second direction. In the second mode, the paper feeding device drives the second drive motor after starting the drive of the first drive motor so as to rotate the shaft in the second direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In a medium conveyance device, when double feeding of the media occurs, it is desired to more appropriately recover the media.

[0006] The medium conveyance device, medium feeding method, and control program according to the embodiment are intended to more appropriately recover the medium when double feeding of the medium occurs.

[0007] The medium conveyance device according to one aspect of the embodiment includes a mounting table, a feeding roller for feeding the medium mounted on the mounting table, a separating roller disposed opposite to the feeding roller, a first motor that generates a first driving force for driving the feeding roller, a second motor that generates a second driving force for driving the separating roller, a first transmission unit that transmits the first driving force to the feeding roller, a second transmission unit that transmits the second driving force to the separating roller, a determination unit that determines whether double feeding of the medium has occurred, and a control unit that controls the first motor and the second motor so as to return the medium to the mounting table when it is determined by the determination unit that double feeding of the medium has occurred. The control unit controls the first motor and the second motor so that the separating roller rotates and then the feeding roller rotates when returning the medium to the mounting table, and at least one of the first transmission unit and the second transmission unit has a play component.

[0008] The medium feeding method according to one aspect of the embodiment includes feeding the medium mounted on the mounting table by a feeding roller, determining whether double feeding of the medium has occurred, and when it is determined that double feeding of the medium has occurred, controlling a first motor that generates a first driving force for driving the feeding roller and a second motor that generates a second driving force for driving a separating roller disposed opposite to the feeding roller so as to temporarily stop the medium and then return it to the mounting table, and controlling the first motor and the second motor so that the separating roller rotates and then the feeding roller rotates when returning the medium to the mounting table. At least one of a first transmission unit that transmits the first driving force to the feeding roller and a second transmission unit that transmits the second driving force to the separating roller has a play component.

[0009] A control program according to one aspect of the embodiment includes a mounting table, a feeding roller for feeding a medium placed on the mounting table, a separating roller disposed opposite to the feeding roller, a first motor that generates a first driving force for driving the feeding roller, a second motor that generates a second driving force for driving the separating roller, a first transmission unit that transmits the first driving force to the feeding roller, and a second transmission unit that transmits the second driving force to the separating roller. The control program determines whether double feeding of the medium has occurred. When it is determined that double feeding of the medium has occurred, the first motor and the second motor are controlled so that the medium is temporarily stopped and then returned to the mounting table. When returning the medium to the mounting table, the first motor and the second motor are controlled so that the separating roller is rotated first and then the feeding roller is rotated. The medium conveyance device is caused to execute this. At least one of the first transmission unit and the second transmission unit has a play component.

[0010] According to the present embodiment, the medium conveyance device, the medium feeding method, and the control program can more appropriately recover the medium when double feeding of the medium occurs.

[0011] 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

[0012]

Figure 1

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Figure 11

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Figure 14

Embodiments for Carrying Out the Invention

[0013] Hereinafter, a media transport device, a media feeding 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.

[0014] FIG. 1 is a perspective view showing a media transport device 100 configured as an image scanner. The media transport device 100 transports and images a media that is a document. The media is paper, thin paper, thick paper, card, booklet, passport, or the like. The media transport device 100 may be a facsimile machine, a copier, a printer multifunction peripheral (MFP), or the like. Note that the transported media may not be a document but a printing object or the like, and the media transport device 100 may be a printer or the like.

[0015] 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, etc. 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.

[0016] 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 cleaning inside the media conveyance device 100 or when handling media.

[0017] The placement table 103 is engaged with the lower housing 101 and places the media to be fed and conveyed. The discharge table 104 is engaged with the upper housing 102 and places the discharged media. Note that the discharge table 104 may be engaged with the lower housing 101.

[0018] The operation device 105 has an input device such as a button and an interface circuit that acquires signals from the input device, receives an input operation by a user, and outputs an operation signal corresponding to the user's input operation. The display device 106 has a display including liquid crystal, organic EL (Electro-Luminescence), etc. and an interface circuit that outputs image data to the display, and displays the image data on the display.

[0019] FIG. 2 is a diagram for explaining the conveyance path inside the media conveyance device 100.

[0020] The conveyance path inside the media conveyance device 100 includes a first media sensor 111, a regulating guide 112, a cam member 113, a flap 114, a feed roller 115, a separation roller 116, a second media sensor 117, an ultrasonic sensor 118, a conveyance roller 119, a first opposing roller 120, a third media sensor 121, an imaging device 122, a discharge roller 123, and a second opposing roller 124, etc.

[0021] Note that the number of each of the feed roller 115, the separation roller 116, the conveying roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124 is not limited to one, and a plurality may be provided. In that case, the plurality of feed rollers 115, separation rollers 116, conveying rollers 119, first opposing rollers 120, discharge rollers 123, and / or second opposing rollers 124 are arranged side by side at intervals in the width direction A2 orthogonal to the medium conveying direction.

[0022] The upper surface of the lower housing 101 forms the lower guide 101a of the medium conveying path, and the lower surface of the upper housing 102 forms the upper guide 102a of the medium conveying path.

[0023] The first medium sensor 111 is arranged upstream of the feed roller 115 and the separation roller 116. The first medium sensor 111 has a contact detection sensor and detects whether or not a medium is placed on the mounting table 103. The first medium sensor 111 generates and outputs a medium 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 first medium sensor 111 is not limited to a contact detection sensor, and any other sensor capable of detecting the presence or absence of a medium, such as an optical detection sensor, may be used as the first medium sensor 111.

[0024] The feed roller 115 is provided on the lower housing 101 and sequentially separates and feeds the medium placed on the mounting table 103 from below. The separation roller 116 is a so-called brake roller or retard roller, is provided on the upper housing 102, and is arranged to face the feed roller 115. The separation roller 116 is provided so as to be rotatable or stoppable in the direction opposite to the medium feed direction. Note that the feed roller 115 may be provided on the upper housing 102, the separation roller 116 may be provided on the lower housing 101, and the feed roller 115 may sequentially feed the medium placed on the mounting table 103 from above.

[0025] The second media sensor 117 is disposed downstream of the feed roller 115 and upstream of the conveyance roller 119, and detects the media conveyed to that position. The second media sensor 117 includes a light emitter and a light receiver provided on one side with respect to the media conveyance path, and a light guide pipe provided at a position facing the light emitter and the light receiver with the media conveyance path therebetween. The light emitter is, for example, an LED (Light Emitting Diode) or the like, and irradiates light toward the media conveyance path. On the other hand, the light receiver is, for example, a photodiode or the like, and receives the light irradiated by the light emitter and guided by the light guide pipe. When media exists at a position facing the second media sensor 117, the light irradiated from the light emitter is blocked by the media, so the light receiver does not detect the light irradiated from the light emitter. The second media sensor 117 generates and outputs a second media signal whose signal value changes between a state where media exists and a state where media does not exist at the position of the second media sensor 117 based on the intensity of the light received by the light receiver.

[0026] Note that instead of the light guide pipe, a reflecting member such as a mirror may be used. Also, the light emitter and the light receiver may be provided to face each other with the media conveyance path therebetween. Further, the second media sensor 117 may detect the presence of the media by a contact detection sensor or the like that passes a predetermined current when the media is in contact or not in contact.

[0027] The ultrasonic sensor 118 is disposed downstream of the feed roller 115, particularly downstream of the second media sensor 117 and upstream of the conveyance roller 119. The ultrasonic sensor 118 includes an ultrasonic transmitter 118a and an ultrasonic receiver 118b. The ultrasonic transmitter 118a and the ultrasonic receiver 118b are disposed in the vicinity of the media conveyance path so as to face each other with the conveyance path therebetween. The ultrasonic transmitter 118a transmits ultrasonic waves. On the other hand, the ultrasonic receiver 118b receives the ultrasonic waves transmitted by the ultrasonic transmitter 118a and transmitted through the media, and generates and outputs an ultrasonic signal which is an electrical signal corresponding to the received ultrasonic waves. When a plurality of media are conveyed overlapping each other, the ultrasonic waves transmitted through the media are attenuated in the air layer between the overlapping media. Therefore, the media conveyance device 100 can detect double feeding of the media based on the ultrasonic signal.

[0028] The conveying roller 119 and the first opposing roller 120 are arranged to face each other on the downstream side of the feeding roller 115 and the separating roller 116 in the medium conveying direction A1. The conveying roller 119 is provided on the upper housing 102 and conveys the medium fed by the feeding roller 115 and the separating roller 116 to the imaging device 122. Note that the conveying roller 119 may be provided on the lower housing 101 and the first opposing roller 120 may be provided on the upper housing 102.

[0029] The third medium sensor 121 is arranged on the downstream side of the conveying roller 119 and the upstream side of the imaging device 122, and detects the medium conveyed to that position. The third medium sensor 121 includes a light emitter and a light receiver provided on one side of the medium conveying path, and a light guide tube provided at a position facing the light emitter and the light receiver across the medium conveying path. The light emitter is an LED or the like and irradiates light toward the medium conveying 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 tube. The third medium sensor 121 generates and outputs a third medium signal whose signal value changes between a state where a medium exists and a state where no medium exists at the position of the third medium sensor 121 based on the intensity of the light received by the light receiver.

[0030] Note that instead of the light guide tube, a reflecting member such as a mirror may be used. Also, the light emitter and the light receiver may be provided to face each other across the medium conveying path. Further, the third medium sensor 121 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 not in contact.

[0031] The imaging device 122 is an example of an imaging unit, and is arranged on the downstream side of the conveying roller 119 and the first opposing roller 120 in the medium conveying direction A1, and images the medium conveyed by the conveying roller 119 and the first opposing roller 120. The imaging device 122 includes a first imaging device 122a and a second imaging device 122b arranged to face each other across the medium conveying path.

[0032] The first imaging device 122a has a line sensor using a CIS (Contact Image Sensor) 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 122a 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 122a generates and outputs an input image by imaging the surface of the conveyed medium according to control from a processing circuit described later.

[0033] Similarly, the second imaging device 122b has a line sensor using 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 122b 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 second imaging device 122b generates and outputs an input image by imaging the back surface of the conveyed medium according to control from a processing circuit described later.

[0034] Note that the medium conveyance device 100 may arrange only one of the first imaging device 122a and the second imaging device 122b and read only one side of the medium. Further, instead of the line sensor using a CIS of an equal magnification optical system type including an imaging element made of CMOS, a line sensor using a CIS of an equal magnification optical system type including an imaging element made of CCD (Charge Coupled Device) may be used. Further, a line sensor of a reduced optical system type including an imaging element made of CMOS or CCD may be used.

[0035] The discharge roller 123 and the second opposing roller 124 are arranged to face each other downstream of the imaging device 122 in the medium conveyance direction A1, that is, downstream of the conveyance roller 119 and the first opposing roller 120. The discharge roller 123 is provided on the upper housing 102, further conveys the medium conveyed by the conveyance roller 119 and the first opposing roller 120 to the downstream side, and discharges it onto the discharge table 104. Note that the discharge roller 123 may be provided on the lower housing 101 and the second opposing roller 124 may be provided on the upper housing 102.

[0036] The medium placed on the placement table 103 is conveyed in the medium conveyance direction A1 between the lower guide 101a and the upper guide 102a by the feeding roller 115 rotating in the direction of arrow A4, that is, the medium feeding direction. The medium conveyance device 100 has, as feeding modes, a separation mode in which the medium is fed while being separated and a non-separation mode in which the medium is fed without being separated. The feeding mode is set by the user using the operation device 105 or an information processing device communicatively connected to the medium conveyance device 100. When the feeding mode is set to the separation mode, the separation roller 116 rotates or stops in the direction of arrow A5, that is, the direction opposite to the medium feeding direction. By the actions of the feeding roller 115 and the separation roller 116, when a plurality of media are placed on the placement table 103, only the medium in contact with the feeding roller 115 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). On the other hand, when the feeding mode is set to the non-separation mode, the separation roller 116 rotates in the direction opposite to arrow A5, that is, in the medium feeding direction.

[0037] The medium is fed between the conveyance roller 119 and the first opposing roller 120 while being guided by the lower guide 101a and the upper guide 102a. The medium is fed between the first imaging device 122a and the second imaging device 122b by the conveyance roller 119 and the first opposing roller 120 rotating in the directions of arrows A6 and A7, respectively. The medium read by the imaging device 122 is discharged onto the discharge table 104 by the discharge roller 123 and the second opposing roller 124 rotating in the directions of arrows A8 and A9, respectively.

[0038] Also, as shown in FIG. 2, the medium conveyance device 100 includes a first motor 131, a second motor 132, and a third motor 133 as drive sources for the respective rollers.

[0039] The first motor 131 is provided in the lower housing 101 and is connected to the feed roller 115 via a first transmission mechanism 131a to drive the feed roller 115. The first motor 131 generates a driving force for driving the feed roller 115 according to a control signal from the processing circuit. The first transmission mechanism 131a includes one or more pulleys, belts, gears, etc. provided between the first motor 131 and a shaft 115a which is the rotation axis of the feed roller 115, and transmits the driving force generated by the first motor 131 to the feed roller 115. Thereby, the first motor 131 rotates the feed roller 115 to feed the medium. The first motor 131 may be disposed in the upper housing 102.

[0040] The second motor 132 is provided in the upper housing 102 separately from the first motor 131, and is connected to the separation roller 116 via a second transmission mechanism 132a to drive the separation roller 116. The second motor 132 generates a driving force for driving the separation roller 116 according to a control signal from the processing circuit. The second transmission mechanism 132a includes one or more pulleys, belts, gears, etc. provided between the second motor 132 and a shaft 116a which is the rotation axis of the separation roller 116. The second transmission mechanism 132a transmits the driving force generated by the second motor 132 to the separation roller 116. Thereby, the second motor 132 rotates the separation roller 116 to separate, feed, and convey the medium to the separation roller 116. The second motor 132 may be disposed in the lower housing 101.

[0041] The third motor 133 is provided in the upper housing 102 separately from the first motor 131 and the second motor 132. The third motor 133 is connected to the conveying roller 119, the discharging roller 123, and the cam member 113 via a third transmission mechanism 133a, and drives the conveying roller 119, the discharging roller 123, and the cam member 113. The third motor 133 generates a driving force for driving the conveying roller 119, the discharging roller 123, and the cam member 113 according to a control signal from the processing circuit. The third transmission mechanism 133a includes one or more pulleys, belts, gears, etc. provided between the third motor 133 and the shaft 119a which is the rotation axis of the conveying roller 119, the shaft 123a which is the rotation axis of the discharging roller 123, and the rotation axis 113a of the cam member 113. The third transmission mechanism 133a transmits the driving force generated by the third motor 133 to the conveying roller 119, the discharging roller 123, and the cam member 113. Thereby, the third motor 133 rotates the conveying roller 119 and the discharging roller 123, and conveys and discharges the medium to and from the conveying roller 119 and the discharging roller 123. That is, the conveying roller 119 and the discharging roller 123 are provided to be driven by the third motor 133. Further, the third motor 133 rotates the cam member 113 and moves the regulating guide 112 that abuts on the cam member 113. The third motor 133 may be disposed in the lower housing 101.

[0042] Thus, in the medium conveying device 100, a common motor is used as the motor for driving the conveying roller 119 and the discharging roller 123, and the motor for moving the regulating guide 112. Thereby, the medium conveying device 100 can reduce the number of motors, and can reduce the device cost and the device weight.

[0043] The first opposing roller 120 is a driven roller that rotates in a driven manner with respect to the conveying roller 119, and the second opposing roller 124 is a driven roller that rotates in a driven manner with respect to the discharge roller 123. Note that the first opposing roller 120 and / or the second opposing roller 124 may be provided so as to be driven by the driving force from the third motor 133. In that case, one or more gears are further provided between the shaft 119a of the conveying roller 119 and the shaft 120a which is the rotation axis of the first opposing roller 120 and / or between the shaft 123a of the discharge roller 123 and the shaft 124a which is the rotation axis of the second opposing roller 124. The third transmission mechanism 133a further transmits the driving force generated by the third motor 133 to the first opposing roller 120 and / or the second opposing roller 124.

[0044] FIG. 3 is a schematic diagram for explaining the regulating guide 112, the cam member 113, and the flap 114. FIG. 3 is a schematic diagram of the regulating guide 112, the cam member 113, and the flap 114 before media feeding as viewed from the side.

[0045] As shown in FIG. 3, the regulating guide 112 is a guide for setting the medium (group) M1 placed on the mounting table 103. The regulating guide 112 is disposed at a position facing the feeding roller 115 and the separating roller 116 in the medium conveying direction A1. The regulating guide 112 is rotatably (oscillatably) supported by the lower housing 101 and supports the lower surface of the medium M1 placed on the mounting table 103 when the feeding of the medium M1 is not being performed. Hereinafter, as shown in FIG. 3, the position where the regulating guide 112 supports the lower surface of the medium M1 placed on the mounting table 103 may be referred to as the set position.

[0046] The cam member 113 is a moving member for moving the regulating guide 112. The cam member 113 is disposed downstream of the regulating guide 112 in the medium conveying direction A1. The cam member 113 is provided so as to be rotatable (oscillatable) by the third motor 133. The cam member 113 is rotatably supported by the lower housing 101 according to the driving force from the third motor 133 and contacts the downstream end of the regulating guide 112 to hold the regulating guide 112 in the set position when the feeding of the medium is not being performed.

[0047] The flap 114 is a stopper for preventing the medium M1 from entering the nip portion of the feed roller 115 and the separation roller 116 before the medium is fed. The flap 114 is disposed at a position facing the regulation guide 112 in the medium conveyance direction A1. The flap 114 is swingably provided on the upper housing 102 and engages with the regulation guide 112 disposed at the set position when the feeding of the medium M1 is not being executed, thereby preventing the medium M1 from entering the nip portion of the feed roller 115 and the separation roller 116.

[0048] That is, the regulation guide 112 regulates the contact of the medium M1 with the feed roller 115 and the separation roller 116 at the set position. The set position is an example of the first position.

[0049] FIG. 4 is a schematic diagram for explaining the operations of the regulation guide 112, the cam member 113, and the flap 114. FIG. 4 is a schematic diagram of the regulation guide 112, the cam member 113, and the flap 114 when feeding the medium, as viewed from the side.

[0050] As shown in FIG. 4, when the feeding of the medium M1 is executed, the cam member 113 swings (rotates) downward (in the direction of arrow A11) according to the driving force from the third motor 133 and separates from the downstream end of the regulating guide 112. When the downstream end of the regulating guide 112 separates from the cam member 113 and is no longer held by the cam member 113, the regulating guide 112 swings downward (in the direction of arrow A12) from the medium conveying surface and separates from the lower surface of the medium M1 placed on the mounting table 103. Hereinafter, as shown in FIG. 4, the position where the regulating guide 112 separates from the lower surface of the medium M1 placed on the mounting table 103 may be referred to as the release position. When the regulating guide 112 is disposed at the release position, the engagement between the flap 114 and the regulating guide 112 is released. As a result, the flap 114 is pushed by the leading end of the medium M1 placed on the mounting table 103 and swings downstream (in the direction of arrow A13), and the medium M1 can enter the nip portion between the feeding roller 115 and the separating roller 116. In this way, when the regulating guide 112 is disposed at the release position, the flap 114 allows the medium M1 to enter the nip portion between the feeding roller 115 and the separating roller 116.

[0051] That is, the regulating guide 112 does not restrict contact with the feeding roller 115 and the separating roller 116 of the medium M1 at the release position. The release position is an example of the second position. The regulating guide 112 is provided so as to be movable between the set position and the release position. The regulating guide 112 is provided so as to move when the cam member 113 rotates.

[0052] Also, as shown in FIGS. 3 and 4, the feeding roller 115 is provided with an outer peripheral surface 115b, a one-way clutch 115c, and the like. The one-way clutch 115c is disposed on the shaft 115a which is the rotation axis of the feeding roller 115. The one-way clutch 115c prevents the outer peripheral surface 115b of the feeding roller 115 from rotating in the direction opposite to the medium feeding direction A4 with respect to the shaft 115a. Thereby, it is prevented that the feeding roller 115 is dragged by the separating roller 116 rotating in the direction A5 opposite to the medium feeding direction and rotates in the direction opposite to the medium feeding direction A4.

[0053] The conveying roller 119 conveys the medium at a conveying speed higher than the feeding speed of the feeding roller 115. Therefore, when the medium reaches the position of the conveying roller 119, the medium is pulled by the conveying roller 119 while being sandwiched between the feeding roller 115 and the separating roller 116. At this time, the outer peripheral surface 115b of the feeding roller 115 rotates according to the medium being clamped due to the function of the one-way clutch 115c, without hindering the conveyance of the medium. Note that the conveying roller 119 may convey the medium at the same conveying speed as the feeding speed of the feeding roller 115.

[0054] In addition, the separating roller 116 is provided with an outer peripheral surface 116b, a torque limiter 116c, etc. The torque limiter 116c is disposed on the shaft 116a which is the rotation shaft of the separating roller 116. The torque limiter 116c defines the maximum torque applied to the separating roller 116. The limit value of the torque limiter 116c is set to a value such that when there is one medium, the rotational force via the torque limiter 116c is cut off, and when there are multiple media, the rotational force via the torque limiter 116c is transmitted. Thereby, when only one medium is conveyed, the separating roller 116 is driven passively according to the feeding roller 115 without rotating according to the driving force from the second motor 132. On the other hand, when multiple media are conveyed, the separating roller 116 rotates in the direction A3 opposite to the medium feeding direction, separates the medium in contact with the feeding roller 115 from the other media, and prevents the occurrence of double feeding. At this time, the outer peripheral surface 116b of the separating roller 116 may apply a force in the direction A5 opposite to the medium feeding direction to the medium while remaining stopped without rotating in the direction A5 opposite to the medium feeding direction.

[0055] FIG. 5 is a schematic diagram for explaining the housing portion 134.

[0056] As shown in FIG. 5, a housing portion 134 is provided in the lower housing 101. The housing portion 134 accommodates deposits such as paper dust or dust adhering to the medium being conveyed, or deposits adhering to the feed roller 115 or the separation roller 116 from the medium being conveyed. The lower guide 101a, which is the medium guide surface of the lower housing 101, has an opening 101b for arranging the feed roller 115. The housing portion 134 is arranged below the feed roller 115 so as to face the opening 101b, and accommodates deposits that have fallen from the medium being conveyed, the feed roller 115, or the separation roller 116 and entered through the gap between the feed roller 115 and the opening 101b. Further, the housing portion 134 is detachably provided from the lower housing 101, that is, from the medium conveying device 100. With the housing portion 134, the medium conveying device 100 can appropriately collect paper dust or dust, and can suppress the accumulation of paper dust or dust in the medium conveying path.

[0057] FIG. 6 is a block diagram showing a schematic configuration of the medium conveying device 100.

[0058] In addition to the above-described configuration, the medium conveying device 100 further includes an interface device 135, a storage device 140, a processing circuit 150, and the like.

[0059] The interface device 135 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (for example, a personal computer, a mobile information terminal, etc.) (not shown) to transmit and receive input images and various information. Further, instead of the interface device 135, 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.

[0060] The storage device 140 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 140 stores computer programs, databases, tables, etc. used for various processes of the medium transport device 100. The computer program may be installed in the storage device 140 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.

[0061] The processing circuit 150 operates based on a program stored in the storage device 140 in advance. The processing circuit is, for example, a CPU (Central Processing Unit). As the processing circuit 150, 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.

[0062] The processing circuit 150 is connected to an operation device 105, a display device 106, a first medium sensor 111, a second medium sensor 117, an ultrasonic sensor 118, a third medium sensor 121, an imaging device 122, a first motor 131, a second motor 132, a third motor 133, an interface device 135, a storage device 140, etc., and controls each of these components. The processing circuit 150 performs drive control of each motor, imaging control of the imaging device 122, etc., based on each medium signal received from each medium sensor. The processing circuit 150 acquires an input image from the imaging device 122 and transmits it to an information processing device via the interface device 135. Further, the processing circuit 150 determines whether or not double feeding of the medium has occurred based on the ultrasonic signal received from the ultrasonic sensor 118, and when double feeding of the medium has occurred, controls each motor to return the medium to the mounting table 103.

[0063] FIG. 7 is a diagram showing a schematic configuration of the storage device 140 and the processing circuit 150.

[0064] As shown in FIG. 7, a control program 141, a determination program 142, etc. are stored in the storage device 140. These programs are functional modules implemented by software operating on a processor. The processing circuit 150 reads each program stored in the storage device 140 and operates according to each read program. Thereby, the processing circuit 150 functions as a control unit 151 and a determination unit 152.

[0065] FIGS. 8 and 9 are flowcharts showing examples of operations of the medium reading process of the medium conveyance device 100.

[0066] Hereinafter, an example of the operation of the medium reading process of the medium conveyance device 100 will be described with reference to the flowcharts shown in FIGS. 8 and 9. Note that the operation flow described below is mainly executed by the processing circuit 150 in cooperation with each element of the medium conveyance device 100 based on a program stored in the storage device 140 in advance.

[0067] First, the control unit 151 waits until an instruction to read a medium is input by the user using the operation device 105 or the information processing device, and it receives an operation signal for instructing the reading of the medium from the operation device 105 or the interface device 135 (step S101).

[0068] Next, the control unit 151 acquires a medium signal from the first medium sensor 111, and based on the acquired medium signal, determines whether a medium is placed on the mounting table 103 (step S102). If no medium is placed on the mounting table 103, the control unit 151 ends the series of steps.

[0069] On the other hand, if a medium is placed on the mounting table 103, the control unit 151 first drives the third motor 133 (step S103). By driving the third motor 133, the control unit 151 rotates the cam member 113 in the direction of arrow A11 in FIG. 3, and moves the regulation guide 112 in the direction of arrow A12 in FIG. 3, that is, from the set position to the release position. Also, by driving the third motor 133, the control unit 151 rotates the conveyance roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124 in the directions of arrows A6, A7, A8, and / or A9 in FIG. 2, respectively.

[0070] Next, the control unit 151 rotates the separation roller 116 in the direction opposite to the medium feeding direction (in the direction of arrow A5 in FIG. 2) by driving the second motor 132 (step S104).

[0071] Next, the control unit 151 rotates the feeding roller 115 in the medium feeding direction (in the direction of arrow A4 in FIG. 2) by driving the first motor 131 to feed the medium (step S105).

[0072] FIG. 10 is a graph for explaining the speed changes of the feeding roller 115, the separation roller 116, and the conveyance roller 119.

[0073] In FIG. 10, graph G11 shows the speed change of the feeding roller 115, graph G12 shows the speed change of the separating roller 116, and graph G13 shows the speed change of the conveying roller 119. Since the speeds of the first opposing roller 120, the discharging roller 123, and the second opposing roller 124 change in the same manner as the speed of the conveying roller 119, hereinafter, the speed change of the conveying roller 119 will be described as a representative. The horizontal axis of each of the graphs G11 to G13 indicates time, and the vertical axis indicates speed.

[0074] On the other hand, graph G14 shows the change in the signal value of the second medium sensor 117, and graph G15 shows the change in the signal value of the third medium sensor 121. The horizontal axis of each of the graphs G14 and G15 indicates time, and the vertical axis indicates the signal value. In the present embodiment, when there is no medium at the position of each sensor, the signal value of the corresponding signal becomes L, and when there is a medium at the position of each sensor, the signal value of the corresponding signal becomes H.

[0075] In FIG. 10, time T1 indicates the start of medium feeding. As described above, since the control unit 151 starts driving the third motor 133, the second motor 132, and the first motor 131 in this order, the conveying roller 119, the separating roller 116, and the feeding roller 115 start rotating sequentially at times T1, T2, and T3. Note that the speed (surface moving speed) V2 of the separating roller 116 is set to a speed lower than the speed (surface moving speed) V1 of the feeding roller 115. Also, the speed (surface moving speed) V3 of the conveying roller 119 is set to a speed higher than the speed (surface moving speed) V1 of the feeding roller 115.

[0076] Further, the control unit 151 starts driving the third motor 133, the second motor 132, and the first motor 131 in this order. Therefore, when the regulation guide 112 moves from the set position and the regulation of the medium by the flap 114 is released, that is, when the leading end of the medium placed on the mounting table 103 contacts the separation roller 116 and the feed roller 115, the feed roller 115 and the separation roller 116 are stopped. Then, before the feed roller 115 starts rotating, the separation roller 116 starts rotating. Thus, as shown in FIG. 4, before the medium group M1 placed on the mounting table 103 enters the nip portion between the feed roller 115 and the separation roller 116, it contacts the separation roller 116. The leading end of the medium group M1 is deflected by the separation roller 116 rotating in the direction opposite to the medium feed direction so that the upper medium is arranged more upstream. Thereby, when the feed roller 115 starts rotating, it is suppressed that a plurality of media enter the nip portion between the feed roller 115 and the separation roller 116 together, and the occurrence of double feeding of the media is suppressed.

[0077] Also, since the separation roller 116 starts rotating before the feed roller 115 starts rotating, it is suppressed that the separation roller 116 is driven by the feed roller 115 before the separation roller 116 starts rotating, and the separation roller 116 can separate the media well.

[0078] Note that the control unit 151 may execute the process of step S104 before the process of step S103, and may operate the third motor 133 after operating the second motor 132 at the start of media feeding. In that case, when the regulation guide 112 moves from the set position and the tip of the media contacts the separation roller 116 and the feeding roller 115, the separation roller 116 rotates and the feeding roller 115 stops. Therefore, also in that case, the media conveyance device 100 controls the first motor 131, the second motor 132, and the third motor 133 so that the feeding roller 115 rotates after the rotating separation roller 116 contacts the media. The tip of the media group M1 is deflected by the separation roller 116 rotating in the direction opposite to the media feeding direction so that the upper media is arranged more upstream. Thereby, when the feeding roller 115 starts to rotate, a plurality of media enter the nip portion of the feeding roller 115 and the separation roller 116 together, and it is possible to suppress the occurrence of double feeding of the media.

[0079] Further, since the separation roller 116 starts to rotate before the feeding roller 115 starts to rotate, it is possible to suppress the separation roller 116 from being driven by the feeding roller 115 before the separation roller 116 starts to rotate, and the separation roller 116 can separate the media well.

[0080] As described above, the control unit 151 controls the first motor 131, the second motor 132, and the third motor 133 so that the feeding roller 115 rotates after the rotating separation roller 116 contacts the media at the start of media feeding. In particular, the control unit 151 operates the first motor 131 after operating the second motor 132 and the third motor 133 at the start of media feeding. Thereby, the control unit 151 can suppress the occurrence of double feeding of the media at the start of media feeding.

[0081] Note that, as described above, the regulation guide 112 is provided to move as the cam member 113 rotates, and the regulation guide 112 and the flap 114 regulate contact with the media feed roller 115 and the separation roller 116 by engaging with each other. Therefore, after driving the third motor 133, it takes a certain amount of time until the regulation guide 112 and the flap 114 move and the media comes into contact with the feed roller 115 and the separation roller 116. The control unit 151 can shorten the time required for feeding the media by driving the third motor 133 to start the movement of the regulation guide 112 and the flap 114 before driving the first motor 131 to start the rotation of the feed roller 115.

[0082] Note that the control unit 151 may wait for a first predetermined time after driving the third motor 133 in step S103 until driving the first motor 131 in step S105. The first predetermined time is set to the time from driving the third motor 133 until the leading end of the media regulated by the flap 114 comes into contact with the separation roller 116 that rotates in the direction opposite to the media feed direction. Thereby, the control unit 151 can surely apply the separating force by the separation roller 116 to the media group before the feeding force by the feed roller 115 is applied, and can more surely suppress the occurrence of double feeding of the media.

[0083] Also, as described above, a torque limiter 116c is provided on the shaft 116a of the separation roller 116. Depending on the arrangement position of the torque limiter 116c, there may be a gap (play component) where the driving force is not transmitted between the shaft 116a and the separation roller 116 (the outer peripheral surface 116b thereof). Therefore, depending on the arrangement position of the torque limiter 116c, it may take a certain amount of time until the driving force from the second motor 132 is transmitted to the separation roller 116. Before driving the first motor 131 to start the rotation of the feed roller 115, the control unit 151 drives the second motor 132 to start the rotation of the separation roller 116, thereby removing the gap (play component) between the shaft 116a and the separation roller 116. Thereby, the control unit 151 can surely apply the separating force by the separation roller 116 to the media group before the feeding force by the feed roller 115 is applied, and can suppress the occurrence of double feeding of the media.

[0084] Note that the control unit 151 may wait for a second predetermined time from driving the second motor 132 in step S104 until driving the first motor 131 in step S105. The second predetermined time is set to the time from driving the second motor 132 until the separation roller 116 surely rotates. Thereby, the control unit 151 can more surely suppress the occurrence of double feeding of the media.

[0085] Next, the control unit 151 waits until the leading end of the conveyed medium passes the position of the second medium sensor 117 (step S106). The control unit 151 periodically acquires a second medium signal from the second medium sensor 117, and when the signal value of the second medium signal changes from a value indicating the absence of the medium to a value indicating the presence of the medium, it is determined that the leading end of the medium has passed the position of the second medium sensor 117.

[0086] Next, the control unit 151 controls the second motor 132 to stop the separation roller 116 (step S107).

[0087] In FIG. 10, time T4 indicates the time when the signal value of the second medium signal changes from L to H, that is, the time when the leading edge of the medium passes the position of the second medium sensor 117. As shown in FIG. 10, when the leading edge of the medium passes the position of the second medium sensor 117, the rotation of the separation roller 116 stops. When the leading edge of the medium passes the position of the second medium sensor 117, it has already passed through the nip portion between the feed roller 115 and the separation roller 116, and the separation of the medium is completed. Therefore, by stopping the separation roller 116, the control unit 151 can appropriately separate the medium while reducing the power consumption and the device temperature of the medium conveyance device 100.

[0088] Next, the control unit 151 waits until the leading edge of the conveyed medium passes the position of the conveyance roller 119 (step S108). The control unit 151 periodically acquires the third medium signal from the third medium sensor 121, and when the signal value of the third medium signal changes from a value indicating the absence of the medium to a value indicating the presence of the medium, it is determined that the leading edge of the medium has passed the position of the third medium sensor 121. The control unit 151 determines that the leading edge of the medium has passed the position of the conveyance roller 119 when the leading edge of the medium passes the position of the third medium sensor 121.

[0089] Next, the control unit 151 controls the first motor 131 to stop the feed roller 115 (step S109).

[0090] In FIG. 10, time T5 indicates the time when the signal value of the third medium signal changes from L to H, that is, the time when the leading edge of the medium passes the position of the third medium sensor 121. As shown in FIG. 10, after the leading edge of the medium passes the position of the third medium sensor 121, the control unit 151 stops the feed roller 115. Thereby, thereafter, the medium is conveyed by the conveyance roller 119, and the feed roller 115 is rotated by the conveyed medium. By stopping the feed roller 115, the control unit 151 can suppress the medium from being pushed by the feed roller 115 and being bent between the feed roller 115 and the conveyance roller 119, thereby preventing a jam of the medium.

[0091] Next, the control unit 151 causes the imaging device 122 to start imaging the medium (step S110).

[0092] Next, the control unit 151 waits until the rear end of the conveyed medium passes the position of the second medium sensor 117 (step S111). The control unit 151 periodically acquires a second medium signal from the second medium sensor 117, and when the signal value of the second medium signal changes from a value indicating the presence of the medium to a value indicating the absence of the medium, it is determined that the rear end of the medium has passed the position of the second medium sensor 117.

[0093] Next, the control unit 151 determines whether there is any medium remaining on the mounting table 103 based on the first medium signal received from the first medium sensor 111 (step S112).

[0094] If there is any medium remaining on the mounting table 103, the control unit 151 controls the second motor 132 to rotate the separation roller 116 in the direction opposite to the medium feeding direction (the direction of arrow A5 in FIG. 2) (step S113).

[0095] Next, the control unit 151 controls the first motor 131 to rotate the feeding roller 115 in the medium feeding direction (the direction of arrow A4 in FIG. 2) to feed the subsequent medium (step S114).

[0096] In FIG. 10, time T6 indicates the time when the signal value of the second medium signal changes from H to L, that is, the time when the rear end of the medium passes the position of the second medium sensor 117. As described above, since the control unit 151 starts driving the second motor 132 and the first motor 131 in this order, the separation roller 116 and the feeding roller 115 start rotating sequentially at times T6 and T7.

[0097] As a result, the control unit 151 can apply the separating force of the separating roller 116 to the stack of media remaining on the mounting table 103 before the feeding force of the feeding roller 115 is applied. Therefore, the leading edge of the stack of media remaining on the mounting table 103 is deflected by the separating roller 116 that rotates in the direction opposite to the media feeding direction so that the upper media are arranged more upstream before entering the nip portion between the feeding roller 115 and the separating roller 116. Therefore, when the feeding roller 115 starts to rotate, it is possible to suppress a plurality of media from entering the nip portion between the feeding roller 115 and the separating roller 116 together and causing double feeding of the media.

[0098] In addition, since the separating roller 116 starts to rotate before the feeding roller 115 starts to rotate, it is possible to suppress the separating roller 116 from being driven by the feeding roller 115 before the separating roller 116 starts to rotate, and the separating roller 116 can separate the media well.

[0099] In this way, when starting to feed the second and subsequent media among the media set on the regulation guide 112, the control unit 151 controls the first motor 131 and the second motor 132 to rotate the separating roller 116 and then rotate the feeding roller 115. As a result, the control unit 151 can also suppress double feeding of the media when starting to feed the second and subsequent media.

[0100] Next, the control unit 151 waits until the trailing edge of the preceding media passes through the imaging position of the imaging device 122 (step S115). The control unit 151 periodically acquires a third media signal from the third media sensor 121, and when the signal value of the third media signal changes from a value indicating the presence of media to a value indicating the absence of media, it determines that the trailing edge of the preceding media has passed through the position of the third media sensor 121. The control unit 151 determines that the trailing edge of the preceding media has passed through the imaging position when a third predetermined time has elapsed after the trailing edge of the preceding media has passed through the position of the third media sensor 121. The third predetermined time is set to a value obtained by adding a margin to the time required for the media to move from the position of the third media sensor 121 to the imaging position.

[0101] Next, the control unit 151 acquires the input image from the imaging device 122, and outputs the acquired input image by transmitting it to the information processing device via the interface device 135 (step S116).

[0102] Next, the control unit 151 returns the process to step S106, and repeats the processes after step S106 for the subsequent medium. In this case, in step S106, the control unit 151 waits until the leading end of the subsequent medium passes the position of the second medium sensor 117 (time T8 in FIG. 10), and in step S107, controls the second motor 132 to stop the separation roller 116. Further, in step S108, the control unit 151 waits until the leading end of the subsequent medium passes the position of the conveyance roller 119 (time T9 in FIG. 10), and in step S109, controls the first motor 131 to stop the feed roller 115.

[0103] On the other hand, in step S112, when no medium remains on the mounting table 103, the control unit 151 waits until the trailing end of the conveyed medium passes the imaging position of the imaging device 122 in the same manner as the process of step S115 (step S117).

[0104] Next, the control unit 151 acquires the input image from the imaging device 122, and outputs the acquired input image by transmitting it to the information processing device via the interface device 135 (step S118).

[0105] Next, the control unit 151 waits until the trailing end of the conveyed medium passes the position of the discharge roller 123 (step S119). The control unit 151 determines that the trailing end of the medium has passed the position of the discharge roller 123 when the fourth predetermined time has elapsed after the trailing end of the medium has passed the position of the third medium sensor 121. The fourth predetermined time is set to a value obtained by adding a margin to the time required for the medium to move from the position of the third medium sensor 121 to the position of the discharge roller 123.

[0106] Next, the control unit 151 controls the third motor 133 so as to stop the conveyance roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124 (step S120).

[0107] Next, the control unit 151 controls the third motor 133 so as to rotate the cam member 113 in the direction opposite to the arrow A11 in FIG. 3 and move the regulation guide 112 in the direction opposite to the arrow A12 in FIG. 3, that is, from the release position to the set position (rotate reversely) (step S121). As a result, the regulation guide 112 is disposed at the set position, and the flap 114 engages with the regulation guide 112 disposed at the set position and is disposed at a position (the position shown in FIG. 3) that blocks the entry of the medium into the nip portion between the feed roller 115 and the separation roller 116. At this time, the conveyance roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124 rotate in the directions opposite to the arrows A6, A7, A8, A9 in FIG. 2, respectively. However, since there is no medium in the medium conveyance path, no problem occurs.

[0108] Next, the control unit 151 controls the third motor 133 so as to stop the cam member 113 (step S122).

[0109] Next, the control unit 151 controls the first motor 131 or the second motor 132 so as to rotate the feed roller 115 or the separation roller 116 (step S123). The control unit 151 controls the first motor 131 or the second motor 132 so as to rotate either one or both of the feed roller 115 and the separation roller 116 in the medium feed direction. The control unit 151 can rotate one of the feed roller 115 and the separation roller 116 to rotate the other roller in a driven manner.

[0110] That is, when the medium is not being fed, the control unit 151 controls the first motor 131 or the second motor 132 to rotate the feed roller 115 or the separation roller 116 with the regulation guide 112 arranged at the set position. The control unit 151 rotates the feed roller 115 or the separation roller 116 to move the deposits adhering to the feed roller 115 or the separation roller 116. As the feed roller 115 and the separation roller 116 rotate, the deposits adhering to the feed roller 115 or the separation roller 116 from the fed medium fall off the feed roller 115 or the separation roller 116 and are accommodated in the accommodation unit 134. Also, as the feed roller 115 and the separation roller 116 rotate, the deposits adhering to each roller or the deposits accumulated around each roller are diffused. Thereby, the contact area between the medium and the rubber portion of each roller is ensured, and the medium conveyance device 100 can suppress a decrease in the feeding force and the separating force of the medium.

[0111] Next, the control unit 151 controls the first motor 131 or the second motor 132 to stop the feed roller 115 or the separation roller 116 (step S124), and ends a series of steps.

[0112] Note that the processes of steps S103, S104, and S105 may be executed in any order. Also, the processes of steps S113 and S114 may be executed in any order. Also, the processes of steps S123 and S124 may be executed at any timing when the medium is not being fed. Alternatively, the processes of steps S123 and S124 may be omitted.

[0113] FIG. 11 is a flowchart showing an example of the operation of the double-feed determination process of the medium conveyance device 100.

[0114] Hereinafter, an example of the operation of the double-feed determination process of the medium conveyance device 100 will be described with reference to the flowchart shown in FIG. 11. Note that the flow of the operation described below is mainly executed by the processing circuit 150 in cooperation with each element of the medium conveyance device 100 based on a program stored in the storage device 140 in advance. The flow of the operation shown in FIG. 11 is periodically executed during the conveyance of the medium.

[0115] First, the determination unit 152 acquires an ultrasonic signal from the ultrasonic sensor 118 (step S201).

[0116] Next, the determination unit 152 determines whether double-feed of the medium has occurred based on the acquired ultrasonic signal (step S202). When the signal value of the ultrasonic signal is equal to or greater than the double-feed threshold value, the determination unit 152 determines that double-feed of the medium has not occurred. When the signal value of the ultrasonic signal is less than the double-feed threshold value, the determination unit 152 determines that double-feed of the medium has occurred. The double-feed threshold value is set to a value between the signal value of the ultrasonic signal when a single sheet of paper is being conveyed and the signal value of the ultrasonic signal when double-feed of the paper has occurred. When it is determined that double-feed of the medium has not occurred, the determination unit 152 returns the process to step S201 and repeats the processes of steps S201 to S202.

[0117] On the other hand, when it is determined by the determination unit 152 that double-feed of the medium has occurred, the control unit 151 temporarily stops the medium reading process (step S203).

[0118] Next, the control unit 151 controls the first motor 131 and the second motor 132 to stop the feed roller 115 and the separation roller 116 (step S204). Note that the determination unit 152 detects that double feeding of the medium has occurred when the leading end of the medium fed by double feeding passes the position of the ultrasonic sensor 118. At this time, the leading end of the medium has not reached the position of the conveying roller 119. Therefore, the control unit 151 controls the third motor 133 to continue rotating the conveying roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124. Thereby, the control unit 151 can continue to convey the medium that was fed in front of the medium fed by double feeding.

[0119] Next, the control unit 151 controls the second motor 132 to rotate the separation roller 116 in the direction opposite to the medium feeding direction (in the direction of arrow A5 in FIG. 2) again (step S205).

[0120] Next, the control unit 151 controls the first motor 131 to rotate the feed roller 115 in the direction opposite to the medium feeding direction (in the direction opposite to arrow A4 in FIG. 2) (reverse rotation) to return the medium fed by double feeding to the mounting table 103 (step S206). The control unit 151 controls the first motor 131 and the second motor 132 so that the peripheral speed of the shaft 115a, which is the rotation axis of the feed roller 115, becomes higher than the peripheral speed of the outer peripheral surface 115b of the feed roller 115 that is driven by the separation roller 116.

[0121] In this way, when it is determined by the determination unit 152 that double feeding of the medium has occurred, the control unit 151 controls the first motor 131 and the second motor 132 to return the medium to the mounting table 103. When returning the medium to the mounting table 103, the control unit 151 controls the first motor 131 and the second motor 132 to rotate the separation roller 116 first and then rotate the feed roller 115. When returning the medium to the mounting table 103, the control unit 151 controls the first motor 131 and the second motor 132 so that the peripheral speed of the shaft 115a, which is the rotation axis of the feed roller 115, becomes higher than the peripheral speed of the outer peripheral surface 115b of the feed roller 115 that is driven by the separation roller 116.

[0122] FIG. 12 is a schematic diagram for explaining an operation of returning the retransmitted medium M2 to the mounting table 103. FIG. 12 is a schematic diagram of the feed roller 115 and the separation roller 116 when retransmission occurs, as viewed from the side.

[0123] As described above, the limit value of the torque limiter 116c provided on the shaft 116a of the separation roller 116 is set to a value such that the rotational force is transmitted through the torque limiter 116c when there are a plurality of media. When the shaft 115a, which is the rotation axis of the feed roller 115, is rotated in the direction A21 opposite to the medium feed direction, the outer peripheral surface 115b of the feed roller 115 does not rotate according to the driving force from the first motor 131 due to the action of the one-way clutch 115c. The outer peripheral surface 115b of the feed roller 115 rotates in the direction A22 opposite to the medium feed direction following the separation roller 116.

[0124] The shaft 115a of the feed roller 115 is provided to rotate at a peripheral speed higher than the peripheral speed of the outer peripheral surface 115b of each feed roller 115 that rotates following the separation roller 116. Thereby, the outer peripheral surface 115b of the feed roller 115 rotates following the rotation of the outer peripheral surface 116b of the separation roller 116 without being inhibited by the one-way clutch 115c. In this way, the feed roller 115 is provided to rotate in the direction A22 opposite to the medium feed direction following the separation roller 116. Further, the separation roller 116 rotates in the direction A5 opposite to the medium feed direction without receiving a load from the feed roller 115.

[0125] Therefore, even when a plurality of media M2 are retransmitted and fed between the separation roller 116 and the feed roller 115, the medium conveyance device 100 can return all the plurality of media M2 to the mounting table 103 by rotating the first motor 131 in the reverse direction.

[0126] As described above, a torque limiter 116c is provided on the shaft 116a of the separation roller 116. Depending on the arrangement position of the torque limiter 116c, there may be a play component where the driving force is not transmitted between the shaft 116a and the separation roller 116. Therefore, if the shaft 115a of the feed roller 115 is rotated before the separation roller 116, the shaft 115a of the feed roller 115 may start to rotate while the separation roller 116 is not locked. In this case, the medium is not sufficiently fixed by the separation roller 116 and is in an unstable state. When the shaft 115a of the feed roller 115 starts to rotate, wrinkles may occur in the medium (the lowermost medium) in contact with the feed roller 115. Further, the separation roller 116 starts to rotate while the outer peripheral surface 115b of the feed roller 115 is not locked. The medium is not sufficiently fixed by the outer peripheral surface 115b of the feed roller 115 and is in an unstable state. When the separation roller 116 starts to rotate, wrinkles may occur in the medium (the uppermost medium) in contact with the separation roller 116.

[0127] The medium conveying device 100 rotates the separation roller 116 and then rotates the shaft 115a of the feed roller 115. Thereby, at the start of rotation of the separation roller 116, the outer peripheral surface 115b of the feed roller 115 is supported by the shaft 115a of the feed roller 115, and the medium is in a stable state by the feed roller 115. Therefore, the medium conveying device 100 can suppress the occurrence of wrinkles in the medium (the uppermost medium) in contact with the separation roller 116. Also, at the start of rotation of the shaft 115a of the feed roller 115, there is no play component between the separation roller 116 and the shaft 116a, and the medium is in a stable state by the separation roller 116. Therefore, the medium conveying device 100 can suppress the occurrence of wrinkles in the medium (the lowermost medium) in contact with the feed roller 115.

[0128] Note that the control unit 151 may wait for a fifth predetermined time from when the separation roller 116 is rotated again in step S205 until the feeding roller 115 is rotated reversely in step S206. The fifth predetermined time is set to the time during which the separation roller 116 rotates by the amount of the play component between the separation roller 116 and the shaft 116a. Thereby, the control unit 151 can start rotating the shaft 115a of the feeding roller 115 after the play component between the separation roller 116 and the shaft 116a has surely disappeared, and can more surely suppress the occurrence of wrinkles in the medium.

[0129] Next, the control unit 151 waits until the medium returns to the mounting table 103 (step S207). The control unit 151 periodically acquires a second medium signal from the second medium sensor 117, and when the signal value of the second medium signal changes from a value indicating the presence of the medium to a value indicating the absence of the medium, it is determined that the downstream end of the reversely running medium has passed the position of the second medium sensor 117. The control unit 151 determines that the medium has returned to the mounting table 103 when a sixth predetermined time has elapsed after the downstream end of the medium has passed the position of the second medium sensor 117. The sixth predetermined time is set to a value obtained by adding a margin to the time required for the reversely running medium to move from the position of the second medium sensor 117 to the upstream end of the nip portion between the feeding roller 115 and the separation roller 116.

[0130] Next, the control unit 151 controls the first motor 131 and the second motor 132 to stop the feeding roller 115 and the separation roller 116 (step S208).

[0131] Next, the control unit 151 resumes the medium reading process (step S209). Since the conveyance roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124 are already rotating, the control unit 151 resumes the medium reading process from the process of step S104 in FIG. 8. Further, the control unit 151 returns the process to step S201 and repeats the processes of steps S201 to S209.

[0132] Note that the feed roller 115 may be provided without a one-way clutch 115c such that the outer peripheral surface 115b rotates following the rotation of the shaft 115a. Also in this case, in step S205, the control unit 151 controls the second motor 132 to re-rotate the separation roller 116 in the direction opposite to the medium feed direction, and in step S206, controls the first motor 131 to rotate the feed roller 115 in the direction opposite to the medium feed direction. That is, when returning the medium to the mounting table 103, the control unit 151 controls the first motor 131 and the second motor 132 such that the separation roller 116 is rotated first and then the feed roller 115 is rotated. However, when returning the medium to the mounting table 103, the control unit 151 controls the first motor 131 and the second motor 132 such that the moving speed of the outer peripheral surface 115b of the feed roller 115 becomes higher than the moving speed of the outer peripheral surface 116b of the separation roller 116.

[0133] Also in this case, when a plurality of media M2 are fed in a double-feed manner between the separation roller 116 and the feed roller 115, the medium conveyance device 100 can return all the plurality of media M2 to the mounting table 103 by rotating the first motor 131 in the reverse direction.

[0134] When double-feed of the medium occurs, there is a medium that is double-fed and fed above the lowermost medium that is in contact with the feed roller 115, and the gravity of the double-fed and fed medium is applied to the medium in contact with the feed roller 115. Therefore, if the feed roller 115 is rotated before the separation roller 116 is rotated, a downward force due to the gravity of the double-fed and fed medium and an upstream-side force due to the feed roller 115 are applied to the lowermost medium. Therefore, a force is applied to the lowermost medium such that the medium is twisted, and wrinkles may occur.

[0135] The media conveyance device 100 rotates the separation roller 116 and then rotates the feed roller 115. There is no media on top of the uppermost media that is in contact with the separation roller 116. Therefore, when the separation roller 116 is rotated before the feed roller 115 is rotated, only the force directed upstream by the separation roller 116 is applied to the media in contact with the separation roller 116, so the possibility of wrinkles occurring is low. Thus, the media conveyance device 100 can suppress the occurrence of wrinkles in the media by rotating the separation roller 116 and then rotating the feed roller 115.

[0136] Also, the control unit 151 makes the moving speed of the outer peripheral surface 115b of the feed roller 115 higher than the moving speed of the outer peripheral surface 116b of the separation roller 116. Thereby, the control unit 151 can cause the lowermost media in contact with the feed roller 115 to catch up with the uppermost media in contact with the separation roller 116. Thus, the control unit 151 can match the timing to return each media that has been fed in multiple sheets to the placement table 103, and can complete the recovery of the media earlier.

[0137] Note that the control unit 151 may control the first motor 131 and the second motor 132 so that the rotation amount of the separation roller 116 (the movement amount of the outer peripheral surface 116b) is larger than the rotation amount of the feed roller 115 (the movement amount of the outer peripheral surface 115b). By increasing the rotation amount of the separation roller 116, the control unit 151 can reliably return the upper media fed together with the media to be fed to the placement table 103. Also, by decreasing the rotation amount of the feed roller 115, the control unit 151 can suppress the lower media from being returned too much and causing wrinkles in the media.

[0138] Also, the media conveyance device 100 may not execute the double-feed determination process.

[0139] As described in detail above, in the medium conveyance device 100, a first motor 131 for driving the feed roller 115, a second motor 132 for driving the separation roller 116, and a third motor 133 for driving the regulation guide 112 are provided separately. In the medium conveyance device 100, at the start of medium feeding, the first motor 131, the second motor 132, and the third motor 133 are controlled so that the feed roller 115 rotates after the rotating separation roller 116 contacts the medium. Thereby, the medium conveyance device 100 can appropriately handle the leading end of the medium group placed on the mounting table 103 by the separation roller 116, and can separate the mediums better.

[0140] Also, in the medium conveyance device 100, a first motor 131 for driving the feed roller 115 and a second motor 132 for driving the separation roller 116 are provided separately. When returning the medium to the mounting table 103 during double feed occurrence, the medium conveyance device 100 controls the first motor 131 and the second motor 132 so that the separation roller 116 rotates and then the shaft 115a of the feed roller 115 rotates. Thereby, the medium conveyance device 100 can stably return the double-fed medium to the mounting table 103, and can more appropriately recover the medium when double feed of the medium occurs.

[0141] Also, the medium conveyance device 100 can stably separate the mediums and stably return the double-fed medium to the mounting table 103 regardless of the number of mediums conveyed together or the type of the conveyed mediums. Also, the medium conveyance device 100 can suppress the occurrence of medium jams when returning the double-fed medium to the mounting table 103.

[0142] FIG. 13 is a diagram for explaining a conveyance path inside a medium conveyance device 200 according to another embodiment.

[0143] The media conveyance device 200 has each part that the media conveyance device 100 has. However, instead of the second motor 132, the third motor 133, the second transmission mechanism 132a, and the third transmission mechanism 133a, the media conveyance device 200 has a second motor 232, a third motor 233, a second transmission mechanism 232a, and a third transmission mechanism 233a.

[0144] The second motor 232 and the second transmission mechanism 232a each have the same configuration as the second motor 132 and the second transmission mechanism 132a, respectively. However, the second motor 232 is connected to the separation roller 116 and the cam member 113 via the second transmission mechanism 232a and drives the separation roller 116 and the cam member 113. The second motor 232 generates a driving force for driving the separation roller 116 and the cam member 113 according to a control signal from the processing circuit 150. The second transmission mechanism 232a includes one or more pulleys, belts, gears, etc. provided between the second motor 232 and the rotation shaft 116a of the separation roller 116 and the rotation shaft 113a of the cam member 113. In particular, between the rotation shaft 116a of the separation roller 116 and the rotation shaft 113a of the cam member 113, one or more gears are provided to make the rotation directions of the separation roller 116 and the cam member 113 different. The second transmission mechanism 232a transmits the driving force generated by the second motor 232 to the separation roller 116 and the cam member 113. Thereby, the second motor 232 rotates the separation roller 116 to separate, feed, and convey the media to the separation roller 116. Also, the second motor 232 rotates the cam member 113 to move the regulation guide 112 that abuts against the cam member 113. That is, in the media conveyance device 200, the cam member 113 is rotatably provided by the second motor 232, and the regulation guide 112 is movably provided by the second motor 232.

[0145] The third motor 233 and the third transmission mechanism 233a each have the same configuration as the third motor 133 and the third transmission mechanism 133a. However, the third motor 233 is connected to the conveyance roller 119 and the discharge roller 123 via the third transmission mechanism 233a, but is not connected to the cam member 113. The third motor 233 generates a driving force for driving the conveyance roller 119 and the discharge roller 123 according to a control signal from the processing circuit 150. The third transmission mechanism 233a includes one or a plurality of pulleys, belts, gears, etc. provided between the third motor 233 and the shaft 119a which is the rotation shaft of the conveyance roller 119 and the shaft 123a which is the rotation shaft of the discharge roller 123. The third transmission mechanism 133a transmits the driving force generated by the third motor 133 to the conveyance roller 119 and the discharge roller 123. Thereby, the third motor 133 rotates the conveyance roller 119 and the discharge roller 123 to convey and discharge the medium to and from the conveyance roller 119 and the discharge roller 123.

[0146] In the medium conveyance device 200, the control unit 151 and the determination unit 152 execute the medium reading process shown in FIGS. 8 and 9 and the double feed determination process shown in FIG. 11.

[0147] In step S103, the control unit 151 drives the third motor 233 to rotate the conveyance roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124. In step S104, the control unit 151 drives the second motor 232 to rotate the separation roller 116 and rotates the cam member 113 to move the regulation guide 112 from the set position to the release position. In step S105, the control unit 151 drives the first motor 131 to rotate the feed roller 115. Thereby, the control unit 151 controls the first motor 131 and the second motor 232 such that the rotating separation roller 116 contacts the medium and then the feed roller 115 rotates at the start of feeding the medium. Further, the control unit 151 operates the second motor 232 and then operates the first motor 131 at the start of feeding the medium.

[0148] In step S107, the control unit 151 controls the second motor 232 to stop the separation roller 116. In step S113, the control unit 151 controls the second motor 232 to rotate the separation roller 116 again. In these operations, the regulation guide 112 does not move from the release position. Also, in step S114, the control unit 151 controls the first motor 131 to rotate the feed roller 115 again. Thereby, the control unit 151 controls the first motor 131 and the second motor 232 so that the separation roller 116 rotates and then the feed roller 115 rotates at the start of feeding of the second and subsequent media among the media set on the regulation guide 112.

[0149] In step S120, the control unit 151 controls the third motor 233 to stop the conveyance roller 119, the first opposing roller 120, the discharge roller 123, and / or the second opposing roller 124. In step S121, the control unit 151 controls the second motor 232 to rotate the cam member 113 and move the regulation guide 112 from the release position to the set position. At this time, although the separation roller 116 rotates in the media feeding direction, since there is no media on the placement table 103, no problem occurs.

[0150] In step S123, the control unit 151 controls the first motor 131 to rotate the feed roller 115. That is, the control unit 151 controls the first motor 131 or the second motor 232 to rotate the feed roller 115 in a state where the regulation guide 112 is arranged at the set position when the media is not being fed. The control unit 151 rotates the feed roller 115 to move the deposits adhering to the feed roller 115 or the separation roller 116. In step S124, the control unit 151 controls the first motor 131 to stop the feed roller 115.

[0151] Also, in S204, S205, and S208 of the double-feed determination process, the control unit 151 controls the second motor 232 to stop or rotate the separation roller 116 again. In these operations, the regulation guide 112 does not move from the release position.

[0152] As described in detail above, even when the medium conveyance device 200 drives the separation roller 116 and the regulation guide 112 with the common second motor 232, it becomes possible to separate the medium better. Further, even when the medium conveyance device 200 drives the separation roller 116 and the regulation guide 112 with the common second motor 232, when double feeding of the medium occurs, it becomes possible to more appropriately recover the medium.

[0153] FIG. 14 is a diagram showing a schematic configuration of a processing circuit 350 in a medium conveyance device according to still another embodiment. The processing circuit 350 is used in place of the processing circuit 150 of the medium conveyance devices 100 and 200, and executes medium reading processing, double feeding determination processing, etc. in place of the processing circuit 150. The processing circuit 350 includes a control circuit 351, a determination circuit 352, and the like. Note that each of these units may be configured by an independent integrated circuit, microprocessor, firmware, or the like.

[0154] The control circuit 351 is an example of a control unit and has the same function as the control unit 151. The control circuit 351 receives an operation signal from the operation device 105 or the interface device 135, a first medium signal from the first medium sensor 111, a second medium signal from the second medium sensor 117, and a third medium signal from the third medium sensor 121. Further, the control circuit 351 receives the determination result of double feeding of the medium from the determination circuit 352. The control circuit 351 controls the first motor 131, the second motor 132 or 232, and the third motor 133 or 233 based on each received piece of information, acquires an input image from the imaging device 122, and outputs it to the interface device 135.

[0155] The determination circuit 352 is an example of a determination unit and has the same function as the determination unit 152. The determination circuit 352 receives an ultrasonic signal from the ultrasonic sensor 118, determines whether double feeding of the medium has occurred based on the received ultrasonic signal, and outputs the determination result to the control circuit 351.

[0156] As described in detail above, even when the processing circuit 350 is used, the medium conveyance device can separate the medium more favorably. Further, even when the processing circuit 350 is used, when double feeding of the medium occurs, the medium conveyance device can recover the medium more appropriately.

Explanation of Signs

[0157] 100, 200 Medium conveyance device, 103 Mounting table, 112 Regulation guide, 113 Cam member, 115 Feeding roller, 115c One-way clutch, 116 Separation roller, 116c Torque limiter, 119 Conveyance roller, 131 First motor, 132, 232 Second motor, 133, 233 Third motor, 151 Control unit, 152 Determination unit

Claims

1. A mounting table; a feeding roller for feeding the medium placed on the placement table; a separation roller disposed opposite the feed roller; a first motor that generates a first driving force for driving the feed roller; a second motor that generates a second driving force for driving the separation roller; a first transmission unit that transmits the first driving force to the feed roller; a second transmission unit that transmits the second driving force to the separation roller; a determination unit that determines whether or not a duplicate feed of media has occurred; a control unit that controls the first motor and the second motor to return the medium to the placement table when the determination unit determines that a multifeed of the medium has occurred, the control unit controls the first motor and the second motor so as to rotate the separation roller and then the feed roller when returning the medium to the placement table; At least one of the first transmission part and the second transmission part has a backlash component. A medium transport device comprising:

2. a one-way clutch that is disposed on a rotation shaft of the feed roller and restricts the feed roller from rotating in a direction opposite to the medium feed direction with respect to the rotation shaft; 2. The medium transport device of claim 1, wherein the control unit controls the first motor and the second motor so that, when returning the medium to the placement table, the peripheral speed of the rotating shaft of the feed roller is higher than the peripheral speed of the outer circumferential surface of the feed roller that is driven by the separation roller.

3. 2. The medium transport device of claim 1, wherein the control unit controls the first motor and the second motor so that, when returning the medium to the placement table, the movement speed of the outer surface of the feed roller is higher than the movement speed of the outer surface of the separation roller.

4. a regulating guide that is movable between a first position that regulates contact of the medium with the feed roller and the separation roller and a second position that does not regulate contact of the medium with the feed roller and the separation roller; a conveying roller disposed downstream of the feed roller and the separation roller in a medium conveying direction; 4. The medium transport device according to claim 1, further comprising: a third motor for moving the regulating guide and driving the transport roller.

5. A feeding roller feeds the medium placed on the placement table, determining whether a media multifeed has occurred; when it is determined that a duplicated medium feed has occurred, a first motor that generates a first driving force for driving the feed roller and a second motor that generates a second driving force for driving a separation roller disposed opposite the feed roller are controlled so as to stop the medium once and then return it to the placement table; controlling the first motor and the second motor so as to rotate the separation roller and then the feed roller when returning the medium to the placement table; a backlash component is present in at least one of a first transmission unit that transmits the first driving force to the feed roller and a second transmission unit that transmits the second driving force to the separation roller; A medium feeding method comprising:

6. 1. A control program for a medium transport device having a mounting table, a feed roller for feeding a medium mounted on the mounting table, a separation roller disposed opposite the feed roller, a first motor for generating a first driving force for driving the feed roller, a second motor for generating a second driving force for driving the separation roller, a first transmission unit for transmitting the first driving force to the feed roller, and a second transmission unit for transmitting the second driving force to the separation roller, determining whether a media multifeed has occurred; When it is determined that a duplicated medium feed has occurred, the first motor and the second motor are controlled so as to stop the medium once and then return it to the placement table; causing the medium transport device to control the first motor and the second motor so as to rotate the separation roller and then the feed roller when returning the medium to the placement table; At least one of the first transmission part and the second transmission part has a backlash component. A control program comprising:

Images