Media transport device, media feeding method, and control program

Abstract

To provide a media transport device that can separate media more effectively. [Solution] The media transport device includes a feed roller for feeding media, a separation roller positioned opposite the feed roller, a restricting guide that is movable between a first position that restricts contact of the media with the feed roller and the separation roller and a second position that does not restrict contact of the media with the feed roller and the separation roller, a first motor for driving the feed roller, a second motor for driving the separation roller, a third motor for moving the restricting guide, and a control unit that controls the first motor, the second motor and the third motor so that when media feeding begins, the feed roller rotates only after the rotating separation roller has contacted the media.

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, it is required to better separate the media so that double feeding of the media does not occur.

[0003] A document separation device including a feed roller, a reverse roller, a lever for detecting a document on a document table, and a reading motor for rotating the reverse roller based on detection information of the lever is disclosed (see Patent Document 1). This document separation device rotates the reverse roller without rotating the feed roller when the reading motor detects a document on the document table by the lever.

[0004] A feeding device including a support portion that supports a medium set in a set portion and moves so that the medium contacts a feeding roller when feeding the medium by the feeding roller is disclosed (see Patent Document 2). This feeding device drives the feeding roller prior to the movement of the support portion when feeding the medium by the feeding roller.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] In a medium conveyance device, it is required to better separate the media.

[0007] The media transport device, media feeding method, and control program according to this embodiment aim to separate the media more effectively.

[0008] A media transport device according to one aspect of the embodiment includes a feed roller for feeding media, a separation roller positioned opposite the feed roller, a restricting guide provided to be movable between a first position that restricts contact of the media with the feed roller and the separation roller and a second position that does not restrict contact of the media with the feed roller and the separation roller, a first motor for driving the feed roller, a second motor for driving the separation roller, a third motor for moving the restricting guide, and a control unit that controls the first motor, the second motor and the third motor so that, at the start of media feeding, the feed roller rotates only after the rotating separation roller has contacted the media.

[0009] A media transport device according to one aspect of the embodiment includes a feed roller for feeding media, a separation roller positioned opposite the feed roller, a restricting guide provided to be movable between a first position that restricts contact of the media with the feed roller and the separation roller and a second position that does not restrict contact of the media with the feed roller and the separation roller, a first motor for driving the feed roller, a second motor for driving the separation roller and moving the restricting guide, and a control unit that controls the first motor and the second motor so that, at the start of media feeding, the feed roller rotates only after the rotating separation roller has contacted the media.

[0010] A media feeding method according to one aspect of the embodiment involves feeding a medium with a feeding roller, and controlling a first motor for driving the feeding roller, a second motor for driving the separating roller, and a third motor for moving a restricting guide that is movable between a first position that restricts contact between the medium and the feeding roller and the separating roller, and a second position that does not restrict contact between the medium and the feeding roller and the separating roller, so that when the feeding of the medium begins, the separating roller, which is positioned opposite the feeding roller in a rotated state, makes contact with the medium before the feeding roller starts to rotate.

[0011] A media feeding method according to one aspect of the embodiment involves feeding a medium using a feeding roller, and controlling a first motor for driving the feeding roller and a second motor for moving a restricting guide that is movable between a first position that drives the feeding roller and the separating roller, and a second position that does not restrict contact of the medium with the feeding roller and the separating roller, so that at the start of medium feeding, the separating roller, which is positioned opposite the feeding roller in a rotated state, makes contact with the medium before the feeding roller starts to rotate.

[0012] A control program relating to one aspect of the embodiment is a control program for a media transport device having a feed roller for feeding a medium, a separation roller positioned opposite the feed roller, a restricting guide provided to be movable between a first position that restricts contact of the medium with the feed roller and the separation roller and a second position that does not restrict contact of the medium with the feed roller and the separation roller, a first motor for driving the feed roller, a second motor for driving the separation roller, and a third motor for moving the restricting guide, wherein the control program causes the media transport device to control the first motor, the second motor, and the third motor so that when the feeding of the medium begins, the rotating separation roller makes contact with the medium before the feed roller starts to rotate.

[0013] A control program relating to one aspect of the embodiment is a control program for a media transport device having a feed roller for feeding a medium, a separation roller positioned opposite the feed roller, a restricting guide provided to be movable between a first position that restricts contact of the medium with the feed roller and the separation roller and a second position that does not restrict contact of the medium with the feed roller and the separation roller, a first motor for driving the feed roller, and a second motor for driving the separation roller and moving the restricting guide, wherein the control program causes the media transport device to control the first motor and the second motor so that, at the start of medium feeding, the rotating separation roller contacts the medium before the feed roller starts to rotate.

[0014] According to this embodiment, the media transport device, media feeding method, and control program are capable of separating the media more effectively.

[0015] The object and effect of the present invention will be recognized and obtained, in particular, by using the components and combinations indicated in the claims. Both the general description above and the detailed description below are illustrative and descriptive, and do not limit the present invention as described in the claims. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing a media transport device 100 according to an embodiment. [Figure 2] This is a diagram illustrating the transport path inside the media transport device 100. [Figure 3] This is a schematic diagram to explain regulatory guideline 112, etc. [Figure 4] This is a schematic diagram illustrating the operation of regulatory guide 112, etc. [Figure 5] This is a schematic diagram illustrating the housing section 134. [Figure 6] This is a block diagram showing the schematic configuration of the media transport device 100. [Figure 7] This figure shows the schematic configuration of the storage device 140 and the processing circuit 150. [Figure 8] This flowchart shows an example of how the media reading process works. [Figure 9] This flowchart shows an example of how the media reading process works. [Figure 10] This graph illustrates the speed changes of the feed roller 115, etc. [Figure 11] This flowchart shows an example of how the double-feed detection process works. [Figure 12] This is a schematic diagram illustrating the operation of returning the media to the mounting tray 103. [Figure 13] This is a diagram illustrating the transport path inside the other media transport device 200. [Figure 14] It is a diagram showing a schematic configuration of another processing circuit 350.

Embodiments for Carrying out the Invention

[0017] Hereinafter, a media conveyance 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.

[0018] FIG. 1 is a perspective view showing a media conveyance device 100 configured as an image scanner. The media conveyance device 100 conveys and images a media that is a document. The media is paper, tissue paper, cardboard, card, booklet, passport, or the like. The media conveyance device 100 may also be a facsimile machine, a copying machine, a printer multifunction peripheral (MFP), or the like. Note that the conveyed media may not be a document but a printing object or the like, and the media conveyance device 100 may be a printer or the like.

[0019] The media conveyance device 100 includes a lower housing 101, an upper housing 102, a placement table 103, a discharge table 104, an operation device 105, a display device 106, and the like. 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.

[0020] The upper housing 102 is disposed at a position covering the upper surface of the media conveyance device 100 and is engaged with the lower housing 101 by a hinge so as to be openable and closable when loading the media or during cleaning inside the media conveyance device 100.

[0021] 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.

[0022] The operating device 105 has input devices such as buttons and an interface circuit that acquires signals from the input devices, accepts input operations from the 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.

[0023] Figure 2 is a diagram illustrating the transport path inside the media transport device 100.

[0024] The transport path inside the media transport device 100 includes a first media sensor 111, a regulating guide 112, a cam member 113, a flap 114, a feeding roller 115, a separation roller 116, a second media sensor 117, an ultrasonic sensor 118, a transport 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, among others.

[0025] Note that the number of each of the feeding rollers 115, separating rollers 116, conveying rollers 119, first opposing rollers 120, discharge rollers 123 and / or second opposing rollers 124 is not limited to one, but may be multiple. In that case, the multiple feeding rollers 115, separating rollers 116, conveying rollers 119, first opposing rollers 120, discharge rollers 123 and / or second opposing rollers 124 are arranged side by side with spacing between them in the width direction A2 perpendicular to the media conveying direction.

[0026] The upper surface of the lower housing 101 forms the lower guide 101a of the media transport path, and the lower surface of the upper housing 102 forms the upper guide 102a of the media transport path.

[0027] The first medium sensor 111 is positioned upstream of the feeding 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 depending on whether or not a medium is placed on the mounting table 103. 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 a light detection sensor, may be used as the first medium sensor 111.

[0028] The feeding roller 115 is provided on the lower housing 101 and separates and feeds the medium placed on the mounting table 103 from the bottom up. The separation roller 116 is a so-called brake roller or retard roller and is provided on the upper housing 102 and positioned opposite the feeding roller 115. The separation roller 116 is provided so as to be rotatable or stoppable in the opposite direction to the medium feeding direction. Alternatively, the feeding roller 115 may be provided on the upper housing 102 and the separation roller 116 on the lower housing 101, and the feeding roller 115 may feed the medium placed on the mounting table 103 from the top up.

[0029] The second medium sensor 117 is positioned downstream of the feed roller 115 and upstream of the transport roller 119, and detects the medium transported to that position. The second medium sensor 117 includes a light emitter and a light receiver provided on one side of the medium transport path, and a light guide tube provided opposite the light emitter and light receiver across the medium transport path. The light emitter is an LED (Light Emitting Diode) or the like, and emits light toward the medium transport path. The light receiver, on the other hand, is a photodiode or the like, and receives the light emitted by the light emitter and guided by the light guide tube. When a medium is present at a position opposite the second medium sensor 117, the light emitted from the light emitter is blocked by the medium, so the light receiver does not detect the light emitted from the light emitter. The second medium sensor 117 generates and outputs a second medium signal whose signal value changes depending on whether a medium is present or absent at the position of the second medium sensor 117, based on the intensity of the light received by the light receiver.

[0030] In addition, a reflective material such as a mirror may be used instead of the light guide tube. Furthermore, the light emitter and light receiver may be provided opposite each other across the medium transport path. The second medium sensor 117 may also detect the presence of the medium by using a contact detection sensor or the like that which supplies a predetermined current when the medium is in contact or when the medium is not in contact.

[0031] The ultrasonic sensor 118 is positioned downstream of the feed roller 115, particularly downstream of the second medium sensor 117 and upstream of the transport 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 positioned near the medium transport path, facing each other across the transport path. The ultrasonic transmitter 118a emits ultrasonic waves. On the other hand, the ultrasonic receiver 118b receives ultrasonic waves emitted by the ultrasonic transmitter 118a and transmitted through the medium, and generates and outputs an ultrasonic signal, which is an electrical signal corresponding to the received ultrasonic waves. When multiple media are transported overlapping, the ultrasonic waves transmitted through the media are attenuated by the air layer between the overlapping media. Therefore, the medium transport device 100 can detect overlapping transport of media based on the ultrasonic signal.

[0032] The transport roller 119 and the first opposing roller 120 are arranged facing each other downstream of the feed roller 115 and the separation roller 116 in the media transport direction A1. The transport roller 119 is provided on the upper housing 102 and transports the media supplied by the feed roller 115 and the separation roller 116 to the imaging device 122. Alternatively, the transport roller 119 may be provided on the lower housing 101 and the first opposing roller 120 on the upper housing 102.

[0033] The third medium sensor 121 is positioned downstream of the transport roller 119 and upstream of the imaging device 122, and detects the medium being transported to its position. The third medium sensor 121 includes a light emitter and a light receiver provided on one side of the medium transport path, and a light guide tube provided opposite the light emitter and light receiver across the medium transport path. The light emitter is an LED or the like, and emits light toward the medium transport path. The light receiver, on the other hand, is a photodiode or the like, and receives the light emitted 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 depending on whether a medium is present or absent at the position of the third medium sensor 121, based on the intensity of the light received by the light receiver.

[0034] In addition, a reflective material such as a mirror may be used instead of the light guide tube. Furthermore, the light emitter and light receiver may be provided opposite each other across the medium transport path. The third medium sensor 121 may also detect the presence of the medium by using a contact detection sensor or the like that which supplies a predetermined current when the medium is in contact or when the medium is not in contact.

[0035] The imaging device 122 is an example of an imaging unit and is positioned downstream of the transport roller 119 and the first opposing roller 120 in the media transport direction A1, and images the media transported by the transport roller 119 and the first opposing roller 120. The imaging device 122 includes a first imaging device 122a and a second imaging device 122b, which are positioned opposite each other across the media transport path.

[0036] The first imaging device 122a has a line sensor using a 1:1 optical system type CIS (Contact Image Sensor) with CMOS (Complementary Metal Oxide Semiconductor) image sensors arranged linearly in the main scanning direction. The first imaging device 122a also has a lens that forms an image on the image sensor and an A / D converter that amplifies the electrical signal output from the image sensor and performs analog-to-digital (A / D) conversion. The first imaging device 122a captures the surface of the transported medium according to control from a processing circuit described later, generates an input image, and outputs it.

[0037] Similarly, the second imaging device 122b has a line sensor with a CIS of the 1:1 optical system type, which has CMOS image sensors arranged linearly in the main scanning direction. The second imaging device 122b also has a lens that forms an image on the image sensor and an A / D converter that amplifies the electrical signal output from the image sensor and performs analog-to-digital (A / D) conversion. The second imaging device 122b generates and outputs an input image by imaging the back surface of the transported medium according to the control from the processing circuit described later.

[0038] Furthermore, the media transport device 100 may have only one of the first imaging device 122a and the second imaging device 122b, and may read only one side of the media. Also, instead of a CIS line sensor of the 1:1 optical system type equipped with a CMOS image sensor, a CIS line sensor of the 1:1 optical system type equipped with a CCD (Charge Coupled Device) image sensor may be used. Alternatively, a reduction optical system type line sensor equipped with a CMOS or CCD image sensor may be used.

[0039] The discharge roller 123 and the second opposing roller 124 are arranged facing each other in the media transport direction A1, downstream from the imaging device 122, that is, downstream from the transport roller 119 and the first opposing roller 120. The discharge roller 123 is provided on the upper housing 102 and transports the media transported by the transport roller 119 and the first opposing roller 120 further downstream and discharges it to the discharge table 104. Alternatively, the discharge roller 123 may be provided on the lower housing 101 and the second opposing roller 124 on the upper housing 102.

[0040] The media placed on the mounting table 103 is transported between the lower guide 101a and the upper guide 102a toward the media transport direction A1 by the feeding roller 115 rotating in the direction of arrow A4, i.e., the media feeding direction. The media transport device 100 has two feeding modes: a separation mode in which the media is fed while being separated, and a non-separation mode in which the media is fed without being separated. The feeding mode is set by the user using the operating device 105 or an information processing device that communicates with the media transport device 100. When the feeding mode is set to separation mode, the separation roller 116 rotates or stops in the direction of arrow A5, i.e., in the opposite direction to the media feeding direction. Due to the action of the feeding roller 115 and the separation roller 116, when multiple media are placed on the mounting table 103, only the media that are in contact with the feeding roller 115 among the media placed on the mounting table 103 are separated. This restricts the transport of media other than the separated media (prevention of double feeding). On the other hand, when the feeding mode is set to non-separation mode, the separation roller 116 rotates in the opposite direction of arrow A5, i.e., in the media feeding direction.

[0041] The medium is fed between the transport roller 119 and the first opposing roller 120, guided by the lower guide 101a and the upper guide 102a. The medium is then fed between the first imaging device 122a and the second imaging device 122b as the transport roller 119 and the first opposing roller 120 rotate in the directions of arrows A6 and A7, respectively. The medium read by the imaging device 122 is then discharged onto the discharge platform 104 as the discharge roller 123 and the second opposing roller 124 rotate in the directions of arrows A8 and A9, respectively.

[0042] Furthermore, as shown in Figure 2, the media transport device 100 has a first motor 131, a second motor 132, and a third motor 133 as drive sources for each roller.

[0043] The first motor 131 is located in the lower housing 101 and is connected to the feed roller 115 via the first transmission mechanism 131a to drive the feed roller 115. The first motor 131 generates a driving force to drive the feed roller 115 in response 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 the 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. As a result, the first motor 131 rotates the feed roller 115 and feeds the medium. The first motor 131 may also be located in the upper housing 102.

[0044] The second motor 132 is provided separately from the first motor 131 in the upper housing 102 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 to drive the separation roller 116 in response 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 the 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. As a result, the second motor 132 rotates the separation roller 116, causing the medium to be separated, fed, and transported to the separation roller 116. The second motor 132 may also be located in the lower housing 101.

[0045] 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 transport roller 119, the discharge roller 123, and the cam member 113 via the third transmission mechanism 133a, and drives the transport roller 119, the discharge roller 123, and the cam member 113. The third motor 133 generates a driving force to drive the transport roller 119, the discharge roller 123, and the cam member 113 in response 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 transport roller 119, the shaft 123a, which is the rotation axis of the discharge 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 conveyor roller 119, the discharge roller 123, and the cam member 113. This causes the third motor 133 to rotate the conveyor roller 119 and the discharge roller 123, thereby transporting and discharging the medium to and from the conveyor roller 119 and the discharge roller 123. In other words, the conveyor roller 119 and the discharge roller 123 are configured to be driven by the third motor 133. The third motor 133 also rotates the cam member 113, moving the regulating guide 112 that contacts the cam member 113. The third motor 133 may be located in the lower housing 101.

[0046] Thus, in the media conveying device 100, a common motor is used to drive the conveying roller 119 and the discharge roller 123, as well as to move the regulating guide 112. This makes it possible to reduce the number of motors in the media conveying device 100, thereby reducing the device cost and weight.

[0047] The first opposing roller 120 is a driven roller that rotates in accordance with the conveying roller 119, and the second opposing roller 124 is a driven roller that rotates in accordance with the discharge roller 123. The first opposing roller 120 and / or the second opposing roller 124 may be provided 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.

[0048] Figure 3 is a schematic diagram illustrating the regulating guide 112, cam member 113, and flap 114. Figure 3 is a schematic diagram of the regulating guide 112, cam member 113, and flap 114 viewed from the side before media feeding.

[0049] As shown in Figure 3, the regulating guide 112 is a guide for setting the media (group) M1 placed on the mounting base 103. The regulating guide 112 is positioned opposite the feed roller 115 and the separation roller 116 in the media transport direction A1. The regulating guide 112 is rotatably (swingingly) supported by the lower housing 101 and supports the lower surface of the media M1 placed on the mounting base 103 when the media M1 is not being fed. Hereafter, as shown in Figure 3, the position in which the regulating guide 112 supports the lower surface of the media M1 placed on the mounting base 103 may be referred to as the set position.

[0050] The cam member 113 is a moving member for moving the regulating guide 112. The cam member 113 is positioned downstream of the regulating guide 112 in the medium transport direction A1. The cam member 113 is rotatably (oscillated) by the third motor 133. The cam member 113 is supported by the lower housing 101 so as to be rotatable according to the driving force from the third motor 133, and when no medium is being fed, it contacts the downstream end of the regulating guide 112 to hold the regulating guide 112 in the set position.

[0051] The flap 114 is a stopper that prevents the medium M1 from entering the nip portion of the feeding roller 115 and the separation roller 116 before the medium is fed. The flap 114 is positioned opposite the regulating guide 112 in the medium transport direction A1. The flap 114 is pivotably mounted on the upper housing 102 and engages with the regulating guide 112, which is in the set position, when the feeding of the medium M1 is not being performed, thereby preventing the medium M1 from entering the nip portion of the feeding roller 115 and the separation roller 116.

[0052] In other words, the regulating guide 112 restricts the contact of the medium M1 with the feeding roller 115 and the separation roller 116 at the set position. The set position is an example of a first position.

[0053] Figure 4 is a schematic diagram illustrating the operation of the regulating guide 112, the cam member 113, and the flap 114. Figure 4 is a schematic diagram of the regulating guide 112, the cam member 113, and the flap 114 viewed from the side during media feeding.

[0054] As shown in Figure 4, when the medium M1 is fed, the cam member 113 swings (rotates) downward (in the direction of arrow A11) according to the driving force from the third motor 133 and moves away from the downstream end of the regulating guide 112. As the downstream end of the regulating guide 112 moves away from the cam member 113 and is no longer held by the cam member 113, it swings downward (in the direction of arrow A12) from the medium transport surface and moves away from the lower surface of the medium M1 placed on the mounting table 103. Hereafter, as shown in Figure 4, the position in which the regulating guide 112 is separated 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 placed in 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 edge of the medium M1 placed on the mounting base 103 and swings downstream (in the direction of arrow A13), allowing the medium M1 to enter the nip portion of the feeding roller 115 and the separation roller 116. In this way, the flap 114 allows the medium M1 to enter the nip portion of the feeding roller 115 and the separation roller 116 when the regulating guide 112 is in the release position.

[0055] In other words, the restricting guide 112 does not restrict the contact of the medium M1 with the feeding roller 115 and the separation roller 116 in the released position. The released position is an example of a second position. The restricting guide 112 is provided to be movable between the set position and the released position. The restricting guide 112 is provided to move by the rotation of the cam member 113.

[0056] Furthermore, as shown in Figures 3 and 4, the feeding roller 115 is provided with an outer circumferential surface 115b and a one-way clutch 115c, etc. The one-way clutch 115c is positioned on the shaft 115a, which is the rotation axis of the feeding roller 115. The one-way clutch 115c prevents the feeding roller 115 (or its outer circumferential surface 115b) from rotating in the opposite direction to the medium feeding direction A4 relative to the shaft 115a. This prevents the feeding roller 115 from being dragged by the separation roller 116, which rotates in the opposite direction A5 to the medium feeding direction, and rotating in the opposite direction to the medium feeding direction A4.

[0057] The transport roller 119 transports the medium at a faster transport speed than the feed roller 115. Therefore, when the medium reaches the position of the transport roller 119, it is held between the feed roller 115 and the separation roller 116 and pulled by the transport roller 119. At this time, the outer surface 115b of the feed roller 115 rotates according to the medium it is holding due to the action of the one-way clutch 115c, and does not obstruct the transport of the medium. The transport roller 119 may also transport the medium at the same transport speed as the feed roller 115.

[0058] Furthermore, the separation roller 116 is provided with an outer circumferential surface 116b and a torque limiter 116c, etc. The torque limiter 116c is positioned on the shaft 116a, which is the rotation axis of the separation roller 116. The torque limiter 116c defines the maximum torque applied to the separation roller 116. The limit value of the torque limiter 116c is set such that when there is only one medium, the rotational force via the torque limiter 116c is cut off, and when there are multiple mediums, the rotational force via the torque limiter 116c is transmitted. As a result, when only one medium is being transported, the separation roller 116 follows the feed roller 115 without rotating according to the driving force from the second motor 132. On the other hand, when multiple mediums are being transported, the separation roller 116 rotates in the opposite direction A5 to the medium feeding direction, separating the medium in contact with the feed roller 115 from the other medium, thereby preventing double feeding. At this time, the outer circumferential surface 116b of the separation roller 116 may remain stationary without rotating in the opposite direction A5 to the medium supply direction, and a force in the opposite direction A5 to the medium supply direction may be applied to the medium.

[0059] Figure 5 is a schematic diagram illustrating the housing section 134.

[0060] As shown in Figure 5, the lower housing 101 is provided with a storage section 134. The storage section 134 stores any attached material such as paper dust or debris that adheres to the conveyed medium, or any attached material that adheres from the conveyed medium to the feed roller 115 or the separation roller 116. The lower guide 101a, which is the medium guide surface of the lower housing 101, has an opening 101b for positioning the feed roller 115. The storage section 134 is positioned below the feed roller 115, facing the opening 101b, and stores any attached material that falls from the conveyed medium, the feed roller 115, or the separation roller 116 and enters through the gap between the feed roller 115 and the opening 101b. The storage section 134 is also detachably mounted from the lower housing 101, i.e., from the medium conveying device 100. The storage section 134 allows the media transport device 100 to properly collect paper dust or debris, and prevents paper dust or debris from accumulating in the media transport path.

[0061] Figure 6 is a block diagram showing the schematic configuration of the media transport device 100.

[0062] In addition to the configuration described above, the media transport device 100 further includes an interface device 135, a storage device 140, and a processing circuit 150.

[0063] The interface device 135 has an interface circuit similar to a serial bus such as USB, and electrically connects to an information processing device (not shown) (e.g., a personal computer, a portable information terminal, etc.) to transmit and receive input images and various types of information. Alternatively, instead of the interface device 135, a communication unit may be used that has an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals via a wireless communication line according to a predetermined communication protocol. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network). The communication unit may also have a wired communication interface device for transmitting and receiving signals via a wired communication line according to a communication protocol such as a wired LAN.

[0064] The storage device 140 includes memory devices such as RAM (Random Access Memory) and ROM (Read Only Memory), fixed disk devices such as hard disks, or portable storage devices such as flexible disks and optical disks. The storage device 140 also stores computer programs, databases, tables, etc., used for various processes of the media transport device 100. The computer programs may be installed into the storage device 140 from a computer-readable portable recording medium using a known setup program. Examples of portable recording media include CD-ROMs (compact disc read-only memory) and DVD-ROMs (digital versatile disc read-only memory).

[0065] The processing circuit 150 operates based on a program pre-stored in the memory device 140. The processing circuit is, for example, a CPU (Central Processing Unit). A DSP (digital signal processor), LSI (large scale integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), etc., may be used as the processing circuit 150.

[0066] The processing circuit 150 is connected to the operating device 105, display device 106, first medium sensor 111, second medium sensor 117, ultrasonic sensor 118, third medium sensor 121, imaging device 122, first motor 131, second motor 132, third motor 133, interface device 135, and storage device 140, and controls each of these parts. Based on the medium signals received from each medium sensor, the processing circuit 150 controls the drive of each motor, the imaging of the imaging device 122, etc. The processing circuit 150 acquires the input image from the imaging device 122 and transmits it to the information processing device via the interface device 135. In addition, based on the ultrasonic signal received from the ultrasonic sensor 118, the processing circuit 150 determines whether or not a double feed of the medium has occurred, and if a double feed of the medium has occurred, it controls each motor to return the medium to the mounting table 103.

[0067] Figure 7 shows a schematic configuration of the storage device 140 and the processing circuit 150.

[0068] As shown in Figure 7, the storage device 140 stores control programs 141 and determination programs 142, etc. Each of these programs is a functional module implemented by software running on the processor. The processing circuit 150 reads each program stored in the storage device 140 and operates according to each program it has read. In this way, the processing circuit 150 functions as a control unit 151 and a determination unit 152.

[0069] Figures 8 and 9 are flowcharts illustrating examples of the operation of the media reading process of the media transport device 100.

[0070] The following describes an example of the operation of the media reading process of the media transport device 100, referring to the flowcharts shown in Figures 8 and 9. The operation flow described below is mainly executed by the processing circuit 150 in cooperation with each element of the media transport device 100, based on a program pre-stored in the storage device 140.

[0071] First, the control unit 151 waits until the user inputs an instruction to read the medium using the operating device 105 or the information processing device, and receives an operation signal instructing the reading of the medium from the operating device 105 or the interface device 135 (step S101).

[0072] Next, the control unit 151 acquires a medium signal from the first medium sensor 111 and determines whether or not a medium is placed on the mounting table 103 based on the acquired medium signal (step S102). If no medium is placed on the mounting table 103, the control unit 151 terminates the series of steps.

[0073] On the other hand, when 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 Figure 3, moving the regulating guide 112 in the direction of arrow A12 in Figure 3, i.e., from the set position to the release position. Also, by driving the third motor 133, the control unit 151 rotates the transport 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 Figure 2, respectively.

[0074] Next, the control unit 151 drives the second motor 132 to rotate the separation roller 116 in the opposite direction to the medium supply direction (in the direction of arrow A5 in Figure 2) (step S104).

[0075] Next, the control unit 151 drives the first motor 131 to rotate the feed roller 115 in the medium feeding direction (in the direction of arrow A4 in Figure 2) and feed the medium (step S105).

[0076] Figure 10 is a graph illustrating the speed changes of the feeding roller 115, the separating roller 116, and the conveying roller 119.

[0077] In Figure 10, graph G11 shows the speed change of the feed roller 115, graph G12 shows the speed change of the separation roller 116, and graph G13 shows the speed change of the conveying roller 119. Since the speeds of the first opposing roller 120, discharge roller 123, and second opposing roller 124 change in the same way as the speed of the conveying roller 119, the speed change of the conveying roller 119 will be described below as a representative example. In each of graphs G11 to G13, the horizontal axis represents time and the vertical axis represents speed.

[0078] Meanwhile, 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. In graphs G14 and G15, the horizontal axis represents time, and the vertical axis represents the signal value. In this 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.

[0079] In Figure 10, time T1 indicates the start of media feeding. As described above, the control unit 151 starts driving the third motor 133, the second motor 132, and the first motor 131 in that order, so the transport roller 119, the separation roller 116, and the feed roller 115 start rotating sequentially at times T1, T2, and T3. The speed (surface movement speed) V2 of the separation roller 116 is set to a lower speed (surface movement speed) V1 of the feed roller 115. Also, the speed (surface movement speed) V3 of the transport roller 119 is set to a higher speed (surface movement speed) V1 of the feed roller 115.

[0080] Furthermore, the control unit 151 starts driving the third motor 133, the second motor 132, and the first motor 131 in that order. Therefore, when the restricting guide 112 moves from its set position and the restriction of the media by the flap 114 is released, that is, when the leading edge of the media placed on the mounting table 103 contacts the separation roller 116 and the feeding roller 115, the feeding roller 115 and the separation roller 116 are stopped. The separation roller 116 starts rotating before the feeding roller 115 starts rotating. Thus, as shown in Figure 4, the media group M1 placed on the mounting table 103 contacts the separation roller 116 before entering the nip portion of the feeding roller 115 and the separation roller 116. The leading edge of the media group M1 is handled by the separation roller 116, which rotates in the opposite direction to the media feeding direction, so that the upper media are positioned further upstream. This prevents multiple media from entering the nip portion of the feed roller 115 and the separation roller 116 together when the feed roller 115 starts to rotate, thereby suppressing the occurrence of double feeding of media.

[0081] Furthermore, by having the separation roller 116 start rotating before the feed roller 115 starts rotating, the separation roller 116 is prevented from being followed by the feed roller 115 before it starts rotating, allowing the separation roller 116 to separate the medium effectively.

[0082] The control unit 151 may perform the processing in step S104 before the processing in step S103, and operate the second motor 132 before the third motor 133 when the medium feeding starts. In that case, when the regulating guide 112 moves from its set position and the leading edge of the medium contacts the separation roller 116 and the feeding roller 115, the separation roller 116 is rotating and the feeding roller 115 is stopped. Therefore, even in that case, the medium transport 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 medium. The leading edges of the medium group M1 are handled by the separation roller 116, which rotates in the opposite direction to the medium feeding direction, so that the upper medium is positioned further upstream. As a result, when the feed roller 115 starts to rotate, multiple media enter the nip portion of the feed roller 115 and the separation roller 116 together, which suppresses the occurrence of double feeding of media.

[0083] Furthermore, by having the separation roller 116 start rotating before the feed roller 115 starts rotating, the separation roller 116 is prevented from being followed by the feed roller 115 before it starts rotating, allowing the separation roller 116 to separate the medium effectively.

[0084] In this way, the control unit 151 controls the first motor 131, the second motor 132, and the third motor 133 so that when the medium feeding starts, the rotating separation roller 116 contacts the medium before the feeding roller 115 starts to rotate. In particular, when the medium feeding starts, the control unit 151 operates the second motor 132 and the third motor 133 before operating the first motor 131. This allows the control unit 151 to suppress the occurrence of double feeding of the medium when the medium feeding starts.

[0085] As described above, the restricting guide 112 is provided to move as the cam member 113 rotates, and the restricting guide 112 and the flap 114 engage with each other to restrict contact of the medium with the feeding roller 115 and the separation roller 116. Therefore, after the third motor 133 is driven, it takes some time for the restricting guide 112 and the flap 114 to move and for the medium to come into contact with the feeding roller 115 and the separation roller 116. The control unit 151 can shorten the time required for feeding the medium by driving the third motor 133 to start the movement of the restricting guide 112 and the flap 114 before driving the first motor 131 to start the rotation of the feeding roller 115.

[0086] The control unit 151 may wait for a first predetermined time between driving the third motor 133 in step S103 and 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 edge of the medium, which was restricted by the flap 114, comes into contact with the separation roller 116, which rotates in the opposite direction to the medium feeding direction. This allows the control unit 151 to reliably apply a separation force from the separation roller 116 to the medium group before the feeding force from the feeding roller 115 is applied, thereby more reliably suppressing the occurrence of double feeding of the medium.

[0087] Furthermore, as described above, a torque limiter 116c is provided on the shaft 116a of the separation roller 116. Depending on the position of the torque limiter 116c, there may be a gap (backlash component) between the shaft 116a and the separation roller 116 (outer surface 116b) where the driving force is not transmitted. Therefore, depending on the position of the torque limiter 116c, it may take some time for the driving force from the second motor 132 to be transmitted to the separation roller 116. The control unit 151 can eliminate the gap (backlash component) between the shaft 116a and the separation roller 116 by driving the second motor 132 to start the rotation of the separation roller 116 before driving the first motor 131 to start the rotation of the feed roller 115. As a result, the control unit 151 can reliably apply the separation force from the separation roller 116 to the media group before the feeding force from the feed roller 115 is applied, thereby suppressing the occurrence of double feeding of the media.

[0088] The control unit 151 may wait for a second predetermined time between driving the second motor 132 in step S104 and 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 is reliably rotating. This allows the control unit 151 to more reliably suppress the occurrence of double feeding of the medium.

[0089] Next, the control unit 151 waits until the leading edge of the transported 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 determines that the leading edge of the medium has passed the position of the second medium sensor 117 when the signal value of the second medium signal changes from a value indicating the absence of medium to a value indicating the presence of medium.

[0090] Next, the control unit 151 controls the second motor 132 to stop the separation roller 116 (step S107).

[0091] In Figure 10, time T4 indicates the time when the signal value of the second medium signal changes from L to H, that is, when the leading edge of the medium passes the position of the second medium sensor 117. As shown in Figure 10, the rotation of the separation roller 116 stops when the leading edge of the medium passes the position of the second medium sensor 117. When the leading edge of the medium passes the position of the second medium sensor 117, it has already passed the nip portion of the feeding roller 115 and the separation roller 116, and the separation of the medium is complete. Therefore, by stopping the separation roller 116, the control unit 151 can reduce the power consumption and temperature of the medium transport device 100 while properly separating the medium.

[0092] Next, the control unit 151 waits until the leading edge of the conveyed medium passes the position of the conveying roller 119 (step S108). The control unit 151 periodically acquires a third medium signal from the third medium sensor 121, and determines that the leading edge of the medium has passed the position of the third medium sensor 121 when the signal value of the third medium signal changes from a value indicating the absence of medium to a value indicating the presence of medium. When 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 conveying roller 119.

[0093] Next, the control unit 151 controls the first motor 131 to stop the feed roller 115 (step S109).

[0094] In Figure 10, time T5 indicates the time when the signal value of the third medium signal changes from L to H, that is, when the leading edge of the medium passes the position of the third medium sensor 121. As shown in Figure 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. As a result, the medium is then transported by the transport roller 119, and the feed roller 115 is carried along by the transported medium. By stopping the feed roller 115, the control unit 151 can suppress the occurrence of medium jamming, which would occur if the medium were pushed by the feed roller 115 and bent between the feed roller 115 and the transport roller 119.

[0095] Next, the control unit 151 instructs the imaging device 122 to start imaging the medium (step S110).

[0096] Next, the control unit 151 waits until the trailing end of the transported 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 determines that the trailing end of the medium has passed the position of the second medium sensor 117 when the signal value of the second medium signal changes from a value indicating the presence of medium to a value indicating the absence of medium.

[0097] Next, the control unit 151 determines whether or not there is any medium remaining on the mounting tray 103 based on the first medium signal received from the first medium sensor 111 (step S112).

[0098] If there is any media remaining on the mounting table 103, the control unit 151 controls the second motor 132 to re-rotate the separation roller 116 in the opposite direction to the media supply direction (in the direction of arrow A5 in Figure 2) (step S113).

[0099] Next, the control unit 151 controls the first motor 131 to re-rotate the feed roller 115 in the medium feeding direction (in the direction of arrow A4 in Figure 2) to feed the subsequent medium (step S114).

[0100] In Figure 10, time T6 indicates the time when the signal value of the second medium signal changes from H to L, that is, when the trailing end of the medium passes the position of the second medium sensor 117. As described above, the control unit 151 starts driving the second motor 132 and the first motor 131 in that order, so the separation roller 116 and the feeding roller 115 start rotating sequentially at times T6 and T7.

[0101] As a result, the control unit 151 can apply a separating force from the separating roller 116 to the media remaining on the mounting table 103 before the feeding force from the feeding roller 115 is applied. Therefore, the leading edges of the media remaining on the mounting table 103 are separated by the separating roller 116, which rotates in the opposite direction to the media feeding direction, so that the upper media are positioned further upstream, before they enter the nip portion between the feeding roller 115 and the separating roller 116. This prevents multiple media from entering the nip portion between the feeding roller 115 and the separating roller 116 together when the feeding roller 115 begins to rotate, thus preventing double feeding of media.

[0102] Furthermore, by having the separation roller 116 start rotating before the feed roller 115 starts rotating, the separation roller 116 is prevented from being followed by the feed roller 115 before it starts rotating, allowing the separation roller 116 to separate the medium effectively.

[0103] In this way, the control unit 151 controls the first motor 131 and the second motor 132 to rotate the separation roller 116 before rotating the feed roller 115 when feeding the second and subsequent media from among the media set in the regulating guide 112 begins. As a result, the control unit 151 can suppress the occurrence of double feeding of media when feeding the second and subsequent media begins.

[0104] Next, the control unit 151 waits until the rear end of the preceding medium passes the imaging position of the imaging device 122 (step S115). The control unit 151 periodically acquires a third medium signal from the third medium sensor 121, and determines that the rear end of the preceding medium has passed the position of the third medium sensor 121 when the signal value of the third medium signal changes from a value indicating the presence of medium to a value indicating the absence of medium. The control unit 151 determines that the rear end of the preceding medium has passed the imaging position when a third predetermined time has elapsed since the rear end of the preceding medium passed the position of the third medium sensor 121. The third predetermined time is set to a value that includes a margin over the time required for the medium to move from the position of the third medium sensor 121 to the imaging position.

[0105] Next, the control unit 151 acquires an 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).

[0106] Next, the control unit 151 returns to step S106 and repeats the processing from step S106 onward for the subsequent medium. In this case, in step S106, the control unit 151 waits until the leading edge of the subsequent medium passes the position of the second medium sensor 117 (time T8 in Figure 10), and in step S107, controls the second motor 132 to stop the separation roller 116. Furthermore, in step S108, the control unit 151 waits until the leading edge of the subsequent medium passes the position of the transport roller 119 (time T9 in Figure 10), and in step S109, controls the first motor 131 to stop the feed roller 115.

[0107] On the other hand, if no medium remains on the mounting table 103 in step S112, the control unit 151 waits in the same manner as in step S115 until the rear end of the transported medium passes the imaging position of the imaging device 122 (step S117).

[0108] Next, the control unit 151 acquires an 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).

[0109] Next, the control unit 151 waits until the rear end of the conveyed medium passes the position of the discharge roller 123 (step S119). The control unit 151 determines that the rear end of the medium has passed the position of the discharge roller 123 when a fourth predetermined time has elapsed since the rear end of the medium passed the position of the third medium sensor 121. The fourth predetermined time is set to a value that includes a margin over 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.

[0110] Next, the control unit 151 controls the third motor 133 to stop the transport roller 119, the first opposing roller 120, the discharge roller 123 and / or the second opposing roller 124 (step S120).

[0111] Next, the control unit 151 controls the third motor 133 (reverse rotation) (step S121) so that the cam member 113 rotates in the opposite direction to arrow A11 in Figure 3, moving the regulating guide 112 in the opposite direction to arrow A12 in Figure 3, i.e., from the release position to the set position. As a result, the regulating guide 112 is positioned in the set position, and the flap 114 is positioned to engage with the regulating guide 112 in the set position, preventing the medium from entering the nip portion of the feeding roller 115 and the separation roller 116 (the position shown in Figure 3). At this time, the transport roller 119, the first opposing roller 120, the discharge roller 123 and / or the second opposing roller 124 rotate in the opposite direction to arrows A6, A7, A8, and A9 in Figure 2, respectively, but no problems occur because there is no medium in the medium transport path.

[0112] Next, the control unit 151 controls the third motor 133 to stop the cam member 113 (step S122).

[0113] Next, the control unit 151 controls the first motor 131 or the second motor 132 to rotate the feeding roller 115 or the separation roller 116 (step S123). The control unit 151 controls the first motor 131 or the second motor 132 to rotate either one or both of the feeding roller 115 and the separation roller 116 in the medium feeding direction. By rotating one of the rollers of the feeding roller 115 and the separation roller 116, the control unit 151 can cause the other roller to rotate as a driven.

[0114] Specifically, when no medium is being fed, the control unit 151 controls the first motor 131 or the second motor 132 to rotate the feeding roller 115 or the separation roller 116 with the regulating guide 112 in the set position. The control unit 151 rotates the feeding roller 115 or the separation roller 116 to move any attached material. As the feeding roller 115 and the separation roller 116 rotate, any attached material from the fed medium falls off the feeding roller 115 or the separation roller 116 and is collected in the storage unit 134. In addition, as the feeding roller 115 and the separation roller 116 rotate, any attached material on each roller or material clumped around each roller is dispersed. As a result, the contact area between the medium and the rubber portion of each roller is ensured, and the medium conveying device 100 can suppress a decrease in the medium feeding force and separation force.

[0115] 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 the series of steps.

[0116] Steps S103, S104, and S105 may be executed in any order. Also, steps S113 and S114 may be executed in any order. Furthermore, steps S123 and S124 may be executed at any time when no media is being supplied. Alternatively, steps S123 and S124 may be omitted.

[0117] Figure 11 is a flowchart showing an example of the operation of the double-feed detection process of the media transport device 100.

[0118] The following describes an example of the operation of the double-feed detection process of the media transport device 100, referring to the flowchart shown in Figure 11. The operation flow described below is mainly executed by the processing circuit 150 in cooperation with each element of the media transport device 100, based on a program stored in the memory device 140 beforehand. The operation flow shown in Figure 11 is executed periodically during media transport.

[0119] First, the determination unit 152 acquires an ultrasonic signal from the ultrasonic sensor 118 (step S201).

[0120] Next, the determination unit 152 determines whether or not a double feed of the medium has occurred based on the acquired ultrasonic signal (step S202). The determination unit 152 determines that a double feed of the medium has not occurred if the signal value of the ultrasonic signal is equal to or greater than the double feed threshold, and determines that a double feed of the medium has occurred if the signal value of the ultrasonic signal is less than the double feed threshold. The double feed threshold is set to a value between the signal value of the ultrasonic signal when one sheet of paper is being transported and the signal value of the ultrasonic signal when a double feed of paper occurs. If it is determined that a double feed of the medium has not occurred, the determination unit 152 returns to step S201 and repeats the process from steps S201 to S202.

[0121] On the other hand, if the determination unit 152 determines that a double feed of the media has occurred, the control unit 151 temporarily stops the media reading process (step S203).

[0122] 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). The determination unit 152 detects that a double feed of the medium has occurred when the leading edge of the double-feeded medium passes the position of the ultrasonic sensor 118. At this time, the leading edge of the medium has not reached the position of the transport roller 119. Therefore, the control unit 151 controls the third motor 133 to keep the transport roller 119, the first opposing roller 120, the discharge roller 123 and / or the second opposing roller 124 rotating. This allows the control unit 151 to continue transporting the medium that was fed before the double-feeded medium.

[0123] Next, the control unit 151 controls the second motor 132 to re-rotate the separation roller 116 in the opposite direction to the medium feeding direction (in the direction of arrow A5 in Figure 2) (step S205).

[0124] Next, the control unit 151 controls the first motor 131 (reverse rotation) to rotate the feed roller 115 in the opposite direction to the medium feeding direction (opposite direction of arrow A4 in Figure 2), thereby returning the medium that has been fed in double feed 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, is higher than the peripheral speed of the outer surface 115b of the feed roller 115 that is driven by the separation roller 116.

[0125] Thus, if the determination unit 152 determines that a double feed 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, is higher than the peripheral speed of the outer surface 115b of the feed roller 115 that is driven by the separation roller 116.

[0126] Figure 12 is a schematic diagram illustrating the operation of returning the double-feeded medium M2 to the mounting table 103. Figure 12 is a schematic diagram of the feed roller 115 and separation roller 116 viewed from the side when double feeding occurs.

[0127] 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 rotational force is transmitted via the torque limiter 116c when there are multiple media. When the shaft 115a, which is the rotation axis of the feed roller 115, is rotated in the opposite direction A21 to the media feeding direction, the outer circumferential 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 circumferential surface 115b of the feed roller 115 rotates in the opposite direction A22 to the media feeding direction, following the separation roller 116.

[0128] The shaft 115a of the feeding roller 115 is configured to rotate at a faster peripheral speed than the peripheral speed of the outer surface 115b of each feeding roller 115, which rotates in conjunction with the separating roller 116. As a result, the outer surface 115b of the feeding roller 115 rotates in accordance with the rotation of the outer surface 116b of the separating roller 116 without being hindered by the one-way clutch 115c. In this way, the feeding roller 115 is configured to rotate in the opposite direction A22 to the medium feeding direction, in conjunction with the separating roller 116. The separating roller 116 also rotates in the opposite direction A5 to the medium feeding direction without being subjected to any load by the feeding roller 115.

[0129] Therefore, even when multiple media M2 are fed in a double-feed manner between the separation roller 116 and the feeding roller 115, the media transport device 100 can return all of the multiple media M2 to the mounting table 103 by reversing the rotation of the first motor 131.

[0130] As described above, the shaft 116a of the separation roller 116 is equipped with a torque limiter 116c, and depending on the position of the torque limiter 116c, there may be a component of play between the shaft 116a and the separation roller 116 in which driving force is not transmitted. 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 rotating before the separation roller 116 is locked. In this case, the medium is not sufficiently fixed by the separation roller 116 and is in an unstable state, and wrinkles may occur in the medium in contact with the feed roller 115 (the medium located at the bottom) when the shaft 115a of the feed roller 115 starts rotating. Furthermore, the separation roller 116 starts rotating before the outer circumferential surface 115b of the feed roller 115 is locked. The media is not sufficiently fixed by the outer surface 115b of the feeding roller 115 and is in an unstable state, which may cause wrinkles to form in the media in contact with the separating roller 116 (the media located at the top) when the separating roller 116 starts rotating.

[0131] The media conveying device 100 rotates the separation roller 116 first, and then rotates the shaft 115a of the feed roller 115. As a result, when the separation roller 116 starts to rotate, the outer surface 115b of the feed roller 115 is supported by the shaft 115a of the feed roller 115, and the media is stabilized by the feed roller 115. Therefore, the media conveying device 100 can suppress the occurrence of wrinkles in the media in contact with the separation roller 116 (the media located at the top). Also, when the shaft 115a of the feed roller 115 starts to rotate, there is no play between the separation roller 116 and the shaft 116a, and the media is stabilized by the separation roller 116. Therefore, the media conveying device 100 can suppress the occurrence of wrinkles in the media in contact with the feed roller 115 (the media located at the bottom).

[0132] The control unit 151 may wait for a fifth predetermined time between re-rotating the separation roller 116 in step S205 and reversing the feed roller 115 in step S206. The fifth predetermined time is set to the time required for the separation roller 116 to rotate by the amount of the play component between the separation roller 116 and the shaft 116a. This allows the control unit 151 to start rotating the shaft 115a of the feed roller 115 only after the play component between the separation roller 116 and the shaft 116a has been completely eliminated, thereby more reliably suppressing the occurrence of wrinkles in the media.

[0133] 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 determines that the downstream end of the reverse-moving medium has passed the position of the second medium sensor 117 when the signal value of the second medium signal changes from a value indicating the presence of medium to a value indicating the absence of medium. The control unit 151 determines that the medium has returned to the mounting table 103 when a sixth predetermined time has elapsed since the downstream end of the medium passed the position of the second medium sensor 117. The sixth predetermined time is set to a value that includes a margin over the time required for the reverse-moving medium to move from the position of the second medium sensor 117 to the upstream end of the nip portion of the feed roller 115 and the separation roller 116.

[0134] 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 S208).

[0135] Next, the control unit 151 restarts the media reading process (step S209). Since the transport 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 restarts the media reading process from step S104 in Figure 8. The control unit 151 then returns to step S201 and repeats the processes from steps S201 to S209.

[0136] The feeding roller 115 may not have a one-way clutch 115c, and its outer surface 115b may be provided to rotate in accordance with the rotation of the shaft 115a. In this case as well, the control unit 151 controls the second motor 132 in step S205 to re-rotate the separation roller 116 in the opposite direction to the medium feeding direction, and controls the first motor 131 in step S206 to rotate the feeding roller 115 in the opposite direction to the medium feeding 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 so that the separation roller 116 is rotated first, and then the feeding 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 so that the moving speed of the outer surface 115b of the feeding roller 115 is higher than the moving speed of the outer surface 116b of the separation roller 116.

[0137] In this case as well, when multiple media M2 are fed in a double-feed manner between the separation roller 116 and the feeding roller 115, the media transport device 100 can return all of the multiple media M2 to the mounting table 103 by reversing the rotation of the first motor 131.

[0138] If double feeding of media occurs, the media that has been double-fed will be on top of the lowest-most media in contact with the feed roller 115, and the weight of the double-fed media will be applied to the media in contact with the feed roller 115. Therefore, if the feed roller 115 is rotated before the separation roller 116 is rotated, the lowest-most media will be subjected to a downward force due to the weight of the double-fed media and an upstream force from the feed roller 115. As a result, the lowest-most media will be subjected to a force that causes it to twist, which may result in wrinkles.

[0139] The media transport device 100 rotates the separation roller 116 first, and then the feed roller 115. There is no media on top of the uppermost media in contact with the separation roller 116. Therefore, when the separation roller 116 is rotated before the feed roller 115 is rotated, only the upstream force from the separation roller 116 is applied to the media in contact with the separation roller 116, making it unlikely that wrinkles will occur. Thus, the media transport device 100 can suppress the occurrence of wrinkles in the media by rotating the separation roller 116 first, and then the feed roller 115.

[0140] Furthermore, the control unit 151 sets the movement speed of the outer surface 115b of the feed roller 115 higher than the movement speed of the outer surface 116b of the separation roller 116. This allows the control unit 151 to bring the lowest medium in contact with the feed roller 115 closer to the uppermost medium in contact with the separation roller 116. Consequently, the control unit 151 can synchronize the timing of returning each medium that has been fed in a double-feed manner back to the mounting table 103, enabling the recovery of the medium to be completed earlier.

[0141] The control unit 151 may also control the first motor 131 and the second motor 132 so that the amount of rotation of the separation roller 116 (the amount of movement of the outer surface 116b) is greater than the amount of rotation of the feed roller 115 (the amount of movement of the outer surface 115b). By increasing the amount of rotation of the separation roller 116, the control unit 151 can reliably return the upper medium, which was fed together with the medium to be fed, to the mounting table 103. In addition, by decreasing the amount of rotation of the feed roller 115, the control unit 151 can suppress the return of the lower medium, which may cause wrinkles in the medium.

[0142] Furthermore, the media transport device 100 does not need to perform a double-feed detection process.

[0143] As detailed above, the media transport device 100 is provided with 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 regulating guide 112, all of which are provided separately. In the media transport device 100, at the start of media feeding, the first motor 131, the second motor 132, and the third motor 133 are controlled so that the feed roller 115 rotates only after the rotating separation roller 116 has made contact with the media. As a result, the media transport device 100 is able to effectively handle the leading edge of the media group placed on the mounting table 103 with the separation roller 116, thereby enabling better separation of the media.

[0144] Furthermore, the media transport device 100 is provided with a first motor 131 for driving the feed roller 115 and a second motor 132 for driving the separation roller 116. When a double feed occurs and the media is returned to the mounting table 103, the media transport device 100 controls the first motor 131 and the second motor 132 to rotate the separation roller 116 first, and then rotate the shaft 115a of the feed roller 115. As a result, the media transport device 100 can stably return the double-fed media to the mounting table 103, and can recover the media more appropriately when a double feed occurs.

[0145] Furthermore, the media transport device 100 can reliably separate media regardless of the number of media being transported together or the type of media being transported, and can reliably return the media that have been fed in multiples to the mounting table 103. In addition, the media transport device 100 can suppress the occurrence of media jams when returning the media that have been fed in multiples to the mounting table 103.

[0146] Figure 13 is a diagram illustrating the transport path inside the media transport device 200 according to another embodiment.

[0147] The media transport device 200 has all the parts of the media transport device 100. However, the media transport device 200 has a second motor 232, a third motor 233, a second transmission mechanism 232a, and a third transmission mechanism 233a instead of a second motor 132, a third motor 133, a second transmission mechanism 132a, and a third transmission mechanism 133a.

[0148] The second motor 232 and the second transmission mechanism 232a 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 to drive the separation roller 116 and the cam member 113 based on 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 shaft 116a, which is the rotation axis of the separation roller 116, and the rotation axis 113a of the cam member 113. In particular, one or more gears are provided between the shaft 116a of the separation roller 116 and the rotation axis 113a of the cam member 113 to make the rotation direction of the separation roller 116 and the rotation direction of 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. As a result, the second motor 232 rotates the separation roller 116, causing the medium to be separated, fed, and transported to the separation roller 116. The second motor 232 also rotates the cam member 113, moving the regulating guide 112 that contacts the cam member 113. In other words, in the medium transport device 200, the cam member 113 is rotatably mounted by the second motor 232, and the regulating guide 112 is movably mounted by the second motor 232.

[0149] The third motor 233 and the third transmission mechanism 233a have the same configuration as the third motor 133 and the third transmission mechanism 133a, respectively. However, the third motor 233 is connected to the transport 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 to drive the transport roller 119 and the discharge roller 123 based on a control signal from the processing circuit 150. The third transmission mechanism 233a includes one or more pulleys, belts, gears, etc., provided between the third motor 233 and the shaft 119a, which is the rotation axis of the transport roller 119, and the shaft 123a, which is the rotation axis of the discharge roller 123. The third transmission mechanism 133a transmits the driving force generated by the third motor 133 to the transport roller 119 and the discharge roller 123. As a result, the third motor 133 rotates the conveying roller 119 and the discharge roller 123, causing the medium to be conveyed to and discharged by the conveying roller 119 and the discharge roller 123.

[0150] In the media transport device 200, the control unit 151 and the determination unit 152 perform the media reading process shown in Figures 8 and 9, and the double-feed determination process shown in Figure 11.

[0151] In step S103, the control unit 151 drives the third motor 233 to rotate the transport 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 regulating guide 112 from the set position to the released position. In step S105, the control unit 151 drives the first motor 131 to rotate the feed roller 115. In this way, the control unit 151 controls the first motor 131 and the second motor 232 so that when the feed roller 115 rotates, the rotating separation roller 116 comes into contact with the medium. Also, when the feed roller 131 starts, the control unit 151 operates the second motor 232 first and then the first motor 131.

[0152] In step S107, the control unit 151 controls the second motor 232 to stop the separation roller 116, and in step S113, the control unit 151 controls the second motor 232 to restart the separation roller 116. In these steps, the regulating guide 112 does not move from the released position. Also, in step S114, the control unit 151 controls the first motor 131 to restart the feed roller 115. As a result, when feeding the second and subsequent media from the media set in the regulating guide 112 begins, the control unit 151 controls the first motor 131 and the second motor 232 to rotate the separation roller 116 before rotating the feed roller 115.

[0153] In step S120, the control unit 151 controls the third motor 233 to stop the transport 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 to move the regulating guide 112 from the release position to the set position. At this time, the separation roller 116 rotates in the medium feeding direction, but no problem occurs because there is no medium on the mounting table 103.

[0154] In step S123, the control unit 151 controls the first motor 131 to rotate the feed roller 115. That is, when no medium is being fed, the control unit 151 controls the first motor 131 or the second motor 232 to rotate the feed roller 115 with the regulating guide 112 in the set position. The control unit 151 rotates the feed roller 115 to move any deposits attached 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.

[0155] Furthermore, in steps S204, S205, and S208 of the double-feed detection process, the control unit 151 controls the second motor 232 to stop or restart the separation roller 116. In these steps, the regulating guide 112 does not move from the release position.

[0156] As detailed above, the media transport device 200 is now able to separate the media more effectively even when the separation roller 116 and the regulating guide 112 are driven by a common second motor 232. Furthermore, the media transport device 200 is now able to recover the media more appropriately in the event of double feeding, even when the separation roller 116 and the regulating guide 112 are driven by a common second motor 232.

[0157] Figure 14 shows a schematic configuration of a processing circuit 350 in a media transport device according to yet another embodiment. The processing circuit 350 is used in place of the processing circuit 150 of the media transport devices 100 and 200, and performs media reading processing, double-feed detection processing, etc., instead of the processing circuit 150. The processing circuit 350 includes a control circuit 351 and a detection circuit 352, etc. Each of these parts may be composed of an independent integrated circuit, microprocessor, firmware, etc.

[0158] The control circuit 351 is an example of a control unit and has the same functions as the control unit 151. The control circuit 351 receives operation signals from the operating device 105 or 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. The control circuit 351 also receives the determination result of double feeding of the medium from the determination circuit 352. Based on the received information, the control circuit 351 controls the first motor 131, the second motor 132 or 232, and the third motor 133 or 233, and also acquires an input image from the imaging device 122 and outputs it to the interface device 135.

[0159] 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 or not a double feed of the medium has occurred based on the received ultrasonic signal, and outputs the determination result to the control circuit 351.

[0160] As detailed above, the media transport device is now able to separate media more effectively, even when using the processing circuit 350. Furthermore, even when using the processing circuit 350, the media transport device is now able to recover media more appropriately in the event of double feeding. [Explanation of Symbols]

[0161] 100, 200 Media transport device, 103 Mounting platform, 112 Regulating guide, 113 Cam member, 115 Feeding roller, 115c One-way clutch, 116 Separation roller, 116c Torque limiter, 119 Transport roller, 131 First motor, 132, 232 Second motor, 133, 233 Third motor, 151 Control unit, 152 Determination unit

Claims

1. A separation unit for separating and feeding the medium, It has a restricting member that is movable between a first position that restricts contact of the medium with the separation part and a second position that does not restrict contact of the medium with the separation part, The regulating member is capable of moving from the first position to the second position and from the second position to the first position. The separation section includes a feeding roller and a separation roller. The feeding roller feeds the medium after the separating roller comes into contact with the medium. The medium fed by the feeding roller comes into contact with the separating roller, to which the driving force is transmitted, before entering the nip portion between the feeding roller and the separating roller. A media transport device characterized by the following features.

2. A separation unit for separating and supplying a medium, It has a restricting member that is movable between a first position that restricts contact of the medium with the separation part and a second position that does not restrict contact of the medium with the separation part, The regulating member is capable of moving from the first position to the second position and from the second position to the first position. The separation section includes a feeding roller and a separation roller. The feeding roller feeds the medium after the separating roller comes into contact with the medium. The medium fed by the feeding roller comes into contact with the separating roller while the motor of the separating roller is rotating, before it enters the nip portion between the feeding roller and the separating roller. A media transport device characterized by the following features.

3. The media transport device according to claim 1 or 2, further comprising a moving member that contacts the restricting member and moves the restricting member.

4. The media transport device according to claim 3, wherein the moving member is arranged in a direction intersecting the media transport direction such that it does not overlap with the shaft which is the rotation axis of at least one roller included in the separation section.

5. The guide surface of the medium has an opening formed therein that allows any deposits attached to the medium to pass through. The media conveying device according to claim 3 or 4, wherein the opening is located below at least one roller included in the separation section.

6. The media transport device according to claim 5, further comprising a storage section for storing deposits that have passed through the opening.

7. The media transport device according to any one of claims 3 to 6, wherein the moving member has a cam mechanism.

8. Further comprising a drive unit that generates driving force, The media transport device according to any one of claims 1 to 7, wherein the restricting member is capable of moving from the first position to the second position and from the second position to the first position by the driving force.

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