Medium feeding device, medium feeding method and control program

Abstract

To provide a medium feeding device, a medium feeding method and a control program which can reduce the time required for feeding a medium, while suppressing the medium from being multiply fed.SOLUTION: A medium feeding device comprises: a placement table; a feeding roller that feeds a medium; a separating roller arranged to oppose to the feeding roller; a pick roller arranged closer to an upstream side than the feeding roller and the separating roller in a medium conveying direction; a first sensor arranged closer to the upstream side than the pick roller, in the medium conveying direction; a second sensor arranged closer to a downstream side than the feeding roller and the separating roller, in the medium conveying direction; and a control part that rotates the pick roller and the feeding roller in the medium feeding direction to feed a plurality of media placed on the placement table. The control part stops the pick roller when the second sensor detects a tip of the preceding medium, and re-rotates the pick roller to make the medium following the preceding medium advance, when the first sensor detects a rear end of the preceding medium.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a medium feeding device, a medium feeding method, and a control program. [Background technology]

[0002] A medium feeding device such as a scanner feeds and captures a plurality of media one by one while separating them. In such a medium feeding device, it is required to reduce the time required for feeding the media. However, if the medium feeding speed is simply increased or the medium feeding interval is shortened, multiple media feeding may occur, making it necessary to reread the media, and as a result, the time required for feeding the media may increase.

[0003] A paper feeder that performs paper feeding and separation operations using a pick roller, a feed roller, and a retard roller has been disclosed (see Patent Document 1). In this paper feeder, the pick roller rotates in the transport direction to feed the paper S1 that it is in contact with, and transport it to a separation nip section consisting of a feed roller and a retard roller. When the trailing edge of paper S1 passes through the nip section of the pick roller, the pick roller continuously feeds paper S2 below paper S1, and performs an operation to bring the leading edge of paper S2 to the separation nip section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-105602 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a medium feeding device, it is required to reduce the time required to feed the media while suppressing the occurrence of double feeding of the media.

[0006] An object of the present invention is to provide a medium feeding device, a medium feeding method, and a control program that are capable of reducing the time required to feed a medium while suppressing the occurrence of double feeding of media. [Means for solving the problem]

[0007] A medium feeding device according to one aspect of the present invention has a loading platform, a feed roller for feeding a medium, a separation roller arranged opposite the feed roller, a pick roller arranged upstream of the feed roller and separation roller in the medium transport direction, a first sensor arranged upstream of the pick roller in the medium transport direction, a second sensor arranged downstream of the feed roller and separation roller in the medium transport direction, and a control unit that feeds multiple media placed on the loading platform by rotating the pick roller and the feed roller in the medium feed direction, and the control unit stops the pick roller when the second sensor detects the leading end of the leading medium, and re-rotates the pick roller to advance the trailing medium when the first sensor detects the trailing end of the leading medium.

[0008] A media feeding method according to one aspect of the present invention feeds multiple media placed on a loading table by rotating a feed roller and a pick roller arranged upstream of the feed roller and a separation roller arranged opposite the feed roller in the media transport direction in the media feeding direction, and when a second sensor arranged downstream of the feed roller and separation roller in the media transport direction detects the leading end of the leading medium, the pick roller is stopped, and when a first sensor arranged upstream of the pick roller in the media transport direction detects the rear end of the leading medium, the pick roller is rotated again to advance the trailing medium.

[0009] A control program according to one aspect of the present invention is a control program for a media transport device having a mounting table, a feed roller for feeding media, a separation roller arranged opposite the feed roller, a pick roller arranged upstream of the feed roller and separation roller in the media transport direction, a first sensor arranged upstream of the pick roller in the media transport direction, and a second sensor arranged downstream of the feed roller and separation roller in the media transport direction, and causes the media transport device to feed multiple media placed on the mounting table by rotating the pick roller and feed roller in the media feed direction, stop the pick roller when the second sensor detects the leading end of the leading medium, and re-rotate the pick roller to advance the trailing medium when the first sensor detects the trailing end of the leading medium. Effect of the Invention

[0010] According to the present invention, the medium feeding device, medium feeding method, and control program are capable of reducing the time required to feed the medium while suppressing the occurrence of double feeding of the medium. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a medium feeding device 100. [Diagram 2] 2 is a diagram for explaining a transport path inside the medium feeding device 100. FIG. [Diagram 3] 1A and 1B are schematic diagrams for explaining a first arm 131 and a second arm 132. FIG. [Figure 4] 1 is a block diagram showing a schematic configuration of a medium feeding device 100. FIG. [Diagram 5] FIG. 2 is a diagram showing a schematic configuration of a storage device 150 and a processing circuit 160. [Figure 6] 10 is a flowchart illustrating an example of the operation of a medium reading process. [Figure 7] 10 is a flowchart illustrating an example of the operation of a medium reading process. [Figure 8] 1A to 1C are schematic diagrams illustrating the feeding of a medium. [Figure 9] 1A to 1C are schematic diagrams illustrating the feeding of a medium. [Figure 10] 13 is a flowchart illustrating an example of an operation of a skew determination process. [Figure 11] 13 is a flowchart showing an example of an operation of a pasting determination process. [Figure 12] 13 is a flowchart illustrating an example of an operation of an image acquisition process. [Figure 13] FIG. 13 is a diagram showing a schematic configuration of a processing circuit 260 according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a medium feeding device, a medium feeding method, and a control program according to one aspect of the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiments, but extends to the inventions described in the claims and their equivalents.

[0013] 1 is a perspective view showing a medium feeding device 100 configured as an image scanner. The medium feeding device 100 conveys a medium, which is an original, and captures an image. The medium is paper, cardboard, card, or the like. The medium feeding device 100 may be a facsimile, a copier, a printer multifunction peripheral (MFP), or the like.

[0014] 1, arrow A1 indicates the substantially vertical direction (height direction), arrow A2 indicates the medium transport direction, arrow A3 indicates the medium discharge direction, and arrow A4 indicates the width direction perpendicular to the medium transport direction A2 or the medium discharge direction A3. In the following, upstream refers to the upstream of the medium transport direction A2 or the medium discharge direction A3, and downstream refers to the downstream of the medium transport direction A2 or the medium discharge direction A3.

[0015] The medium feeding device 100 includes a first housing 101, a second housing 102, a placement table 103, a discharge table 104, an operation device 105, a display device 106, and the like.

[0016] The second housing 102 is disposed inside the first housing 101 and rotatably engaged with the first housing 101 by a hinge so that the second housing 102 can be opened and closed when a medium is jammed or when the inside of the medium feeding device 100 is cleaned.

[0017] The placement table 103 engages with the first housing 101 so that the medium to be transported can be placed thereon. The placement table 103 is provided on the side surface of the first housing 101 on the medium supply side so as to be movable in the height direction A1. The placement table 103 is disposed at the bottom end position so that the medium can be easily placed thereon when the medium is not being transported, and when the medium is being transported, the uppermost medium placed on the placement table 103 rises to a position where it comes into contact with a pick roller, which will be described later.

[0018] The discharge stage 104 is formed on the second housing 102. The discharge stage 104 places the media discharged from the discharge ports of the first housing 101 and the second housing 102 thereon.

[0019] The operation device 105 has an input device such as a button and an interface circuit for acquiring a signal from the input device, accepts an input operation by a user, and outputs an operation signal according to the user's input operation. The display device 106 has a display including a liquid crystal, an organic EL (Electro-Luminescence), or the like, and an interface circuit for outputting image data to the display, and displays the image data on the display. The display device 106 may be a liquid crystal display with a touch panel function. In that case, the operation device 105 has an interface circuit for acquiring an input signal from the touch panel.

[0020] FIG. 2 is a diagram for explaining the transport path inside the medium feeding device 100. As shown in FIG.

[0021] The transport path inside the medium feeding device 100 has a first media sensor 111, a first encoder 112, a pick roller 113, a feed roller 114, a separation roller 115, a second encoder 116, a second media sensor 117, a third media sensor 118, a first skew sensor 119, a second skew sensor 120, an ultrasonic sensor 121, first to sixth transport rollers 122a-f, first to sixth driven rollers 123a-f, a fourth media sensor 124, and an imaging device 125, etc.

[0022] The number of each of the pick roller 113, the feed roller 114, the separation roller 115, the first to sixth conveyor rollers 122a-f, and / or the first to sixth driven rollers 123a-f is not limited to one, and may be more than one. In this case, the multiple feed rollers 114, the separation roller 115, the first to sixth conveyor rollers 122a-f, and / or the first to sixth driven rollers 123a-f are arranged at intervals in the width direction A4.

[0023] The second housing 102 is disposed opposite the first housing 101 across the medium transport path. The surface of the first housing 101 facing the second housing 102 forms a first guide 101a of the medium transport path, and the surface of the second housing 102 facing the first housing 101 forms a second guide 102a of the medium transport path.

[0024] The first medium sensor 111 is disposed on the mounting table 103, that is, upstream of the feed roller 114 and the separation roller 115, and detects the state of the medium on the mounting table 103. The first medium sensor 111 determines whether or not a medium is placed on the mounting table 103 by using a contact detection sensor that passes a predetermined current when the medium is in contact or not in contact. The first medium sensor 111 generates and outputs a first medium signal whose signal value changes depending on whether the medium is placed on the mounting table 103 or not. 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.

[0025] The first encoder 112 is an example of a first sensor. The first encoder 112 is disposed in the second housing 102 upstream of the feed roller 114 and the separation roller 115 in the medium conveying direction A2, and detects the movement of the medium in contact with the first encoder 112 to detect the rear end of the medium being fed. In particular, the first encoder 112 is disposed upstream of the pick roller 113 in the medium conveying direction A2, particularly in the vicinity of the pick roller 113. The first encoder 112 has a disk in which a large number of slits (light transmission holes) are formed and which is provided to rotate according to the medium being fed, and a light emitter and a light receiver which are provided to face each other across the disk. The light emitter is an LED (Light Emitting Diode) or the like, and emits light toward the disk (light receiver). The light receiver is a photodiode or the like, and receives the light emitted by the light emitter via the disk. The light receiver detects the number of times that the state changes from a state in which there is a slit between the light emitter and the light receiver to a state in which there is no slit and the light is blocked by the disk within a predetermined period. The light receiver detects the movement distance of the medium being fed by multiplying the detected number of changes by the distance that the outer circumferential surface of the first encoder 112 moves when the disk rotates by the distance between two adjacent slits. The first encoder 112 generates and outputs a distance signal indicating the detected movement distance. When the rear end of the medium being fed passes the position of the first encoder 112, the movement distance of the medium changes from a value greater than 0 to 0, so that the first encoder 112 can detect the rear end of the medium from the movement distance of the medium. Note that the first encoder 112 is not limited to an optical encoder, and may be any encoder such as a mechanical encoder, a magnetic encoder, or an electromagnetic induction encoder.

[0026] Pick roller 113 is disposed in second housing 102, upstream of feed roller 114 and separation roller 115 in media transport direction A2. Pick roller 113 comes into contact with the uppermost medium among the media placed on mounting table 103, which has been raised to approximately the same height as the media transport path, and transports the medium downstream. A one-way clutch is provided between pick roller 113 and a motor that imparts a driving force to pick roller 113, so as to restrict rotation of pick roller 113 in the opposite direction to media feed direction A11.

[0027] The feed roller 114 is provided in the second housing 102 downstream of the pick roller 113, and feeds the medium placed on the placement table 103 and fed by the pick roller 113 further downstream. When a plurality of feed rollers 114 are provided, each feed roller 114 is provided so as to rotate independently by a separate motor. The feed rollers 114 may also be provided so as to rotate integrally by a common motor. A one-way clutch is provided between the feed roller 114 and the motor that applies a driving force to the feed roller 114 so as to restrict the rotation of the feed roller 114 in the direction opposite to the medium feeding direction A12.

[0028] The separation roller 115 is disposed in the first housing 101 facing the feed roller 114. The separation roller 115 is a so-called brake roller or retard roller, and is provided so as to be rotatable or stoppable in the direction A13 opposite to the medium feeding direction. The feed roller 114 and the separation roller 115 function as a separation unit that separates the medium, and separates the medium and feeds it one by one. The feed roller 114 is disposed above the separation roller 115, and the medium feeding device 100 feeds the medium by a so-called top-down method. Note that the feed roller 114 may be disposed below the separation roller 115, and the medium feeding device 100 may feed the medium by a so-called bottom-up method.

[0029] A torque limiter that specifies the limit value of the torque applied to the separation roller 115 is provided between the separation roller 115 and the motor that applies a driving force to the separation roller 115. The limit value of the torque limiter is set to a value such that the rotational force via the torque limiter is cut off when there is one medium, and the rotational force via the torque limiter is transmitted when there are multiple media. As a result, when only one medium is transported, the separation roller 115 does not rotate according to the driving force from the motor, but follows the feed roller 114. On the other hand, when multiple media are transported, the separation roller 115 rotates in the opposite direction A13 to the medium feeding direction, and separates the medium in contact with the feed roller 114 from the other media, thereby preventing double feeding. At this time, the outer circumferential surface of the separation roller 115 may apply a force in the opposite direction A13 to the medium feeding direction to the medium while it is stopped without rotating in the opposite direction A13 to the medium feeding direction.

[0030] The separation roller 115 is supported by the first housing 101 by an arm 115a. The separation roller 115 is attached to one end of the arm 115a, and the other end of the arm 115a is attached to the first housing 101. The arm 115a is provided to the first housing 101 so as to be rotatable (swingable). A biasing force is applied to the arm 115a by a biasing member (not shown) such as a spring member or a rubber member in the upward direction, that is, in the direction in which the separation roller 115 moves toward the feed roller 114 side. In addition, a rotational force for rotating (swinging) is applied to the arm 115a by a driving force from a motor (not shown). The medium feeding device 100 adjusts the pressing force with which the separation roller 115 presses the feed roller 114 by rotating (swinging) the arm 115a.

[0031] The second encoder 116 is an example of a third sensor. The second encoder 116 is provided on the shaft, which is the rotation axis of the separation roller 115, in the second housing 102, and detects the rotation of the separation roller 115. The second encoder 116 has a disk in which a large number of slits (light transmission holes) are formed and which is provided to rotate according to the rotation of the separation roller 115, and a light emitter and a light receiver which are provided to face each other across the disk. The light emitter is an LED or the like, and emits light toward the disk (light receiver). The light receiver is a photodiode or the like, and receives the light emitted by the light emitter through the disk. The light receiver detects the number of changes in a predetermined period from a state in which there is a slit between the light emitter and the light receiver to a state in which there is no slit and the light is blocked by the disk. The light receiver detects the movement distance of the outer circumferential surface of the separation roller 115 by multiplying the detected number of changes by the distance that the outer circumferential surface of the separation roller 115 moves when the disk rotates by the distance between two adjacent slits. In addition, a fixed slit is provided between the light emitter and the light receiver to make the output signal (pulse) two-phase, and the light receiver detects the rotation direction of the disk based on the rising timing of the output signal of each phase. The second encoder 116 generates and outputs a rotation signal indicating the detected moving distance and the rotation direction of the disk (stop / forward / reverse). Note that the second encoder 116 is not limited to an optical encoder, and may be any encoder such as a mechanical encoder, a magnetic encoder, or an electromagnetic induction encoder.

[0032] The second medium sensor 117 is an example of a second sensor. The second medium sensor 117 is disposed downstream of the feed roller 114 and the separation roller 115 and upstream of the first conveying roller 122a and the first driven roller 123a in the medium conveying direction A2, and detects the medium conveyed to the arrangement position. In particular, the second medium sensor 117 is disposed near the feed roller 114 and the separation roller 115. The second medium sensor 117 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 emits light toward the medium conveying path. On the other hand, the light receiver is a photodiode or the like, and receives the light emitted by the light emitter and guided by the light guide tube. The second medium sensor 117 generates and outputs a second medium signal whose signal value changes depending on whether a medium is present or not at the position of the second medium sensor 117, based on the intensity of light received by the optical receiver.

[0033] The third medium sensor 118 is disposed downstream of the feed roller 114 and the separation roller 115 and upstream of the first conveyor roller 122a and the first driven roller 123a in the medium conveying direction A2, and detects the medium conveyed to the arrangement position. That is, the third medium sensor 118 is disposed between the feed roller 114 and the separation roller 115 and the first conveyor roller 122a and the first driven roller 123a in the medium conveying direction A2. In particular, the third medium sensor 118 is disposed downstream of the second medium sensor 117 in the medium conveying direction A2. The third medium sensor 118 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 emits light toward the medium conveying path. On the other hand, the light receiver 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 118 generates and outputs a third medium signal whose signal value changes depending on whether a medium is present or not at the position of the third medium sensor 118, based on the intensity of light received by the optical receiver.

[0034] The first skew sensor 119 and the second skew sensor 120 are disposed downstream of the feed roller 114 and the separation roller 115 and upstream of the first transport roller 122a and the first driven roller 123a in the medium transport direction A2, and detect the medium transported to their positions. In particular, the first skew sensor 119 and the second skew sensor 120 are disposed downstream of the third medium sensor 118 in the medium transport direction A2. The first skew sensor 119 and the second skew sensor 120 may be disposed upstream of the third medium sensor 118 in the medium transport direction A2. The first skew sensor 119 and the second skew sensor 120 are disposed at the same position in the medium transport direction A2 and arranged side by side with an interval in the width direction A4.

[0035] The first skew sensor 119 includes a light emitter and a light receiver provided on one side of the media transport path, and a light guide tube provided at a position facing the light emitter and the light receiver across the media transport path. The light emitter is an LED or the like, and emits light toward the media transport path. Meanwhile, the light receiver is a photodiode or the like, and receives the light emitted by the light emitter and guided by the light guide tube. The first skew sensor 119 generates and outputs a first skew signal, the signal value of which changes depending on whether a medium is present or not at the position of the first skew sensor 119, based on the intensity of the light received by the light receiver.

[0036] The second skew sensor 120 includes a light emitter and a light receiver provided on one side of the media transport path, and a light guide tube provided at a position facing the light emitter and the light receiver across the media transport path. The light emitter is an LED or the like, and emits light toward the media transport path. Meanwhile, the light receiver is a photodiode or the like, and receives the light emitted by the light emitter and guided by the light guide tube. The second skew sensor 120 generates and outputs a second skew signal whose signal value changes depending on whether a medium is present or not at the position of the second skew sensor 120, based on the intensity of the light received by the light receiver.

[0037] The ultrasonic sensor 121 is disposed downstream of the feed roller 114 and the separation roller 115 and upstream of the first conveyor roller 122a and the first driven roller 123a. The ultrasonic sensor 121 may be disposed downstream of the first conveyor roller 122a and the first driven roller 123a. The ultrasonic sensor 121 includes an ultrasonic transmitter 121a and an ultrasonic receiver 121b disposed in the vicinity of the medium conveying path and facing each other across the medium conveying path. The ultrasonic transmitter 121a emits ultrasonic waves. Meanwhile, the ultrasonic receiver 121b receives ultrasonic waves emitted by the ultrasonic transmitter 121a and passing through the medium, and generates and outputs an ultrasonic signal, which is an electrical signal corresponding to the received ultrasonic waves. The ultrasonic signal indicates the magnitude of the ultrasonic waves passing through the medium being fed.

[0038] The first to sixth conveying rollers 122a-f and the first to sixth driven rollers 123a-f are arranged facing each other downstream of the feed roller 114 and the separation roller 115 in the medium conveying direction A2. The first to sixth conveying rollers 122a-f and the first to sixth driven rollers 123a-f convey the medium fed by the feed roller 114 and the separation roller 115 downstream. The sixth conveying roller 122f and the sixth driven roller 123f discharge the medium to the discharge tray 104.

[0039] The fourth medium sensor 124 is disposed downstream of the first transport roller 122a and the first driven roller 123a and upstream of the second transport roller 122b and the second driven roller 123b in the medium transport direction A2, and detects the medium transported to the arrangement position. The fourth medium sensor 124 may be disposed downstream of the second transport roller 122b and the second driven roller 123b in the medium transport direction A2 and upstream of the imaging device 125. The fourth medium sensor 124 includes a light emitter and a light receiver provided on one side of the medium transport path, and a light guide tube provided at a position facing the light emitter and the light receiver across the medium transport path. The light emitter is an LED or the like, and emits light toward the medium transport path. On the other hand, the light receiver is a photodiode or the like, and receives the light emitted by the light emitter and guided by the light guide tube. The fourth medium sensor 124 generates and outputs a fourth medium signal whose signal value changes depending on whether a medium is present or not at the position of the fourth medium sensor 124, based on the intensity of light received by the optical receiver.

[0040] A reflective member such as a mirror may be used instead of a light guide in second medium sensor 117, third medium sensor 118, first skew sensor 119, second skew sensor 120 and / or fourth medium sensor 124. In each sensor, the light emitter and the light receiver may be disposed opposite each other with the medium transport path in between. Each sensor may detect the presence of the medium using a contact detection sensor or the like that passes a predetermined current when the medium is in contact or when the medium is not in contact.

[0041] The imaging device 125 is disposed downstream of the first and second transport rollers 122a-b in the medium transport direction A2, and captures images of the medium transported by the first and second transport rollers 122a-b and the first and second driven rollers 123a-b. The imaging device 125 includes a first imaging device 125a and a second imaging device 125b disposed opposite each other across the medium transport path. The first imaging device 125a is provided in the second housing 102, and the second imaging device 125b is provided in the first housing 101.

[0042] The first imaging device 125a has a line sensor using a CIS (Contact Image Sensor) of a life-size optical system type having imaging elements using CMOS (Complementary Metal Oxide Semiconductor) linearly arranged in the main scanning direction. The first imaging device 125a also has a lens that forms an image on the imaging elements, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging elements. The first imaging device 125a captures an image of the surface of the medium being transported, generates an input image, and outputs it.

[0043] Similarly, the second imaging device 125b has a line sensor using a CIS of a life-size optical system type having CMOS imaging elements arranged in a line in the main scanning direction. The second imaging device 125b also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The second imaging device 125b captures the back side of the medium being transported to generate an input image and output it.

[0044] The medium feeding device 100 may have only one of the first imaging device 125a and the second imaging device 125b arranged to read only one side of the medium. Also, instead of a CIS line sensor of an equal magnification optical system type having a CMOS imaging element, a CIS line sensor of an equal magnification optical system type having a CCD (Charge Coupled Device) imaging element may be used. Also, a reduction optical system type line sensor having a CMOS or CCD imaging element may be used.

[0045] The medium placed on the placement table 103 is transported between the first guide 101a and the second guide 102a in the medium transport direction A2 by the rotation of the pick roller 113 and the feed roller 114 in the medium feed direction A11 and A12, respectively. The medium feeding device 100 has a separation mode in which the medium is separated while being fed, and a non-separation mode in which the medium is not separated while being fed. The feeding mode is set by the user using the operation device 105 or an information processing device that is communicatively connected to the medium feeding device 100. When the feeding mode is set to the separation mode, the separation roller 115 rotates or stops in the direction of the arrow A13, i.e., in the opposite direction to the medium feeding direction. This restricts the feeding of media other than the separated medium (prevention of double feeding). On the other hand, when the feeding mode is set to the non-separation mode, the separation roller 115 rotates in the opposite direction to the arrow A13, i.e., in the medium feeding direction.

[0046] While being guided by first guide 101a and second guide 102a, first and second transport rollers 122a-b rotate in the directions of arrows A14-15, thereby sending the medium to an imaging position of imaging device 125, and the medium is imaged by imaging device 125. Furthermore, the medium is discharged onto discharge tray 104 by third to sixth transport rollers 122c-f rotating in the directions of arrows A16-19, respectively.

[0047] 3(A) and (B) are schematic diagrams for explaining the first arm 131 and the second arm 132. Fig. 3(A) shows a schematic diagram of the periphery of the separation roller 115 of the first housing 101 seen from above with the second housing 102 open, and Fig. 3(B) shows a schematic diagram of the periphery of the feed roller 114 and the separation roller 115 seen from the side.

[0048] 3A and 3B, the medium feeding device 100 has a first arm 131 and a second arm 132. In the example shown in Fig. 3A and 3B, the separation rollers 115 are arranged at intervals in the width direction A4 perpendicular to the medium transport direction. In this case, the feed rollers 114 are also arranged at intervals in the width direction A4 perpendicular to the medium transport direction so as to face each separation roller 115.

[0049] The first arm 131 is a plate-like member extending along the medium transport direction A2, and is provided on the first housing 101 so as to be swingable (rotatable) in the height direction A1 around the upstream end 131a. The first arm 131 is disposed between the separation rollers 115 in the width direction A4 perpendicular to the medium transport direction. The first arm 131 has a first protrusion 131b. The first protrusion 131b is provided so as to be swingable so as to protrude from the first guide 101a, i.e., from the guide surface of the medium, and is disposed upstream of the nip portion N between the feed roller 114 and the separation roller 115 in the medium transport direction A2 in a state protruding from the first guide 101a.

[0050] The second arm 132 is a plate-like member extending along the medium conveying direction A2, and is provided in the first housing 101 so as to be swingable (rotatable) in the height direction A1 around the upstream end 132a. The second arm 132 is disposed between the separation rollers 115 in the width direction A4 perpendicular to the medium conveying direction. A gap is provided in the center of the second arm 132 in the width direction A4, and the first arm 131 is disposed in the center (gap) of the second arm 132 in the width direction A4. The second arm 132 has a second protrusion 132b. The second protrusion 132b is provided so as to be swingable so as to protrude from the first guide 101a, i.e., from the guide surface of the medium, and is disposed so as to overlap the nip portion N of the feed roller 114 and the separation roller 115 in the medium conveying direction A2 when protruding from the first guide 101a. That is, the second protrusion 132b is disposed downstream of the first protrusion 131b in the medium transport direction A2.

[0051] The medium fed to the separation section is subjected to a pressing force from the pick roller 113 and the feed roller 114. As a result, the medium may buckle between the pick roller 113 and the feed roller 114, and the separation roller 115 may slip, causing the medium to jam. In response to this, the first protrusion 131b and the second protrusion 132b push up the center of the medium being fed in the width direction A4. As a result, the medium being fed bends in a wavy manner in the width direction A4, so that the medium feeding device 100 can stiffen the medium and improve the rigidity of the medium moving along the medium transport direction A2.

[0052] Therefore, even when a thin paper having a low stiffness is fed to the separation section as a medium, the medium feeding device 100 can suppress the occurrence of buckling of the medium and the occurrence of a jam of the medium. Also, even when a medium made of multiple sheets of paper such as an envelope or copy paper is fed to the separation section, the medium has a rigidity that can withstand the separating force of the separation roller 115, so the medium feeding device 100 can suppress the occurrence of a jam of the medium. In particular, the medium feeding device 100 stiffens the medium in two stages using the first protrusion 131b and the second protrusion 132b that are arranged at different positions in the medium conveying direction A2. As a result, the medium has a higher rigidity, so that the medium feeding device 100 can suppress the occurrence of buckling or jamming of the medium even when multiple media are fed to the separation section in an overlapping state.

[0053] FIG. 4 is a block diagram showing a schematic configuration of the medium feeding device 100. As shown in FIG.

[0054] In addition to the above-mentioned components, the medium feeding device 100 further includes a first motor 141, a second motor 142, a third motor 143, an interface device 144, a storage device 150, a processing circuit 160, and the like.

[0055] The first motor 141 includes one or more motors, and generates a driving force for rotating the feed roller 114 in the medium feed direction A12 in response to a control signal from the processing circuit 160, causing the feed roller 114 to feed the medium. When multiple feed rollers 114 are provided, a separate motor is provided for each feed roller 114 so that each feed roller 114 rotates independently. Note that the feed rollers 114 may be provided so as to rotate together with a common motor.

[0056] The second motor 142 is an example of a motor. The second motor 142 includes one or more motors, and generates a driving force for rotating the separation roller 115 in the direction A13 opposite to the medium feeding direction in response to a control signal from the processing circuit 160, causing the separation roller 115 to separate the medium.

[0057] The third motor 143 includes one or more motors, and rotates the pick roller 113 and the first to sixth transport rollers 122a-f to transport the medium in response to a control signal from the processing circuit 160. The first to sixth driven rollers 123a-f may be provided so as to rotate according to the driving force of the third motor 143, rather than being driven by the first to sixth transport rollers 122a-f. The third motor 143 also moves the mounting table 103 or oscillates the separation roller 115 in response to a control signal from the processing circuit 160.

[0058] The interface device 144 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (not shown, for example, a personal computer, a portable information terminal, etc.) to transmit and receive input images and various information. Also, instead of the interface device 144, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface circuit for transmitting and receiving signals through a wireless communication line in accordance with a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network). The communication unit may have a wired communication interface circuit for transmitting and receiving signals through a wired communication line in accordance with a communication protocol such as a wired LAN.

[0059] The storage device 150 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. The storage device 150 also stores computer programs, databases, tables, and the like used for various processes of the medium feeding device 100. The computer programs may be installed in the storage device 150 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or the like.

[0060] The processing circuit 160 operates based on a program previously stored in the storage device 150. The processing circuit is, for example, a CPU (Central Processing Unit). The processing circuit 160 may be, for example, a DSP (digital signal processor), an LSI (large scale integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array).

[0061] The processing circuit 160 is connected to the operation device 105, the display device 106, the first medium sensor 111, the first encoder 112, the second encoder 116, the second medium sensor 117, the third medium sensor 118, the first skew sensor 119, the second skew sensor 120, the ultrasonic sensor 121, the fourth medium sensor 124, the imaging device 125, the first motor 141, the second motor 142, the third motor 143, the interface device 144, the storage device 150, and the like, and controls each of these parts. The processing circuit 160 performs drive control of the first motor 141, the second motor 142, and the third motor 143, image capture control of the imaging device 125, and the like, based on signals received from each sensor. The processing circuit 160 acquires an input image from the imaging device 125, and transmits it to the information processing device via the interface device 144.

[0062] FIG. 5 is a diagram showing a schematic configuration of the storage device 150 and the processing circuit 160. As shown in FIG.

[0063] 5, the storage device 150 stores a control program 151, a detection program 152, a skew determination program 153, and an attachment determination program 154. Each of these programs is a functional module implemented by software that runs on a processor. The processing circuit 160 reads each program stored in the storage device 150 and operates according to the read program. As a result, the processing circuit 160 functions as a control unit 161, a detection unit 162, a skew determination unit 163, and an attachment determination unit 164.

[0064] 6 and 7 are flowcharts showing an example of the operation of the medium reading process of the medium feeding device 100. In FIG.

[0065] An example of the operation of the medium reading process of the medium feeding device 100 will be described below with reference to the flowcharts shown in Figures 6 and 7. The flow of the operation described below is executed mainly by the processing circuit 160 in cooperation with each element of the medium feeding device 100 based on a program previously stored in the storage device 150. This flowchart describes the case where the feeding mode is set to the separation mode.

[0066] First, the control unit 161 waits until a user inputs an instruction to read a medium using the operation device 105 or an information processing device, and an operation signal instructing the user to read a medium is received from the operation device 105 or the interface device 144 (step S101).

[0067] Next, control unit 161 acquires a medium signal from first medium sensor 111, and determines whether or not a medium is placed on placement table 103 based on the acquired medium signal (step S102). If no medium is placed on placement table 103, control unit 161 ends the series of steps.

[0068] On the other hand, when a medium is placed on the placement table 103, the control unit 161 sets the arrival flag, jam flag, and skew flag to OFF (step S103). The arrival flag is set to OFF every time a medium is fed, and is set to ON when it is determined in a process described below that the leading edge of the medium following the medium to be fed has reached the separation unit. The jam flag is set to OFF every time a medium is fed, and is set to ON when it is determined in a process described below that a medium jam has occurred. The skew flag is set to OFF every time a medium is fed, and is set to ON when it is determined in a skew determination process described below that a medium skew has occurred and the medium skew has been corrected.

[0069] Next, the control unit 161 drives the third motor 143 to move the placement table 103 to a position where the medium can be fed. The control unit 161 drives the third motor 143 to rotate the pick roller 113 in the medium feeding direction A11, and drives the first motor 141 to rotate the feed roller 114 in the medium feeding direction A12, thereby feeding the medium placed on the placement table 103. The control unit 161 drives the third motor 143 to rotate the first to sixth conveyance rollers 122a to f, thereby conveying the medium placed on the placement table 103. Furthermore, the control unit 161 controls the second motor 142 to generate a driving force to rotate the separation roller 115 in the opposite direction A13 to the medium feeding direction, thereby rotating the separation roller 115 in the opposite direction A13 to the medium feeding direction (step S104). Hereinafter, the driving force that rotates the separation roller 115 in the direction A13 opposite to the medium feeding direction may be referred to as a separation driving force.

[0070] The control unit 161 may control the second motor 142 to hold the separation roller 115. In this case, the control unit 161 controls the second motor 142 to hold (hold a stopped state) the separation roller 115 while energizing the second motor 142. In this case, the control unit 161 controls the second motor 142 to generate a separation driving force and rotate the separation roller 115 in the direction A13 opposite to the medium feeding direction when the second medium sensor 117 detects the leading edge of the medium.

[0071] If the separation roller 115 rotates in the opposite direction A13 to the medium feeding direction immediately after the start of feeding the medium, the medium waiting in the separation section is pushed out in the medium conveying direction A2 by the pick roller 113 and the feed roller 114 and pushed back by the separation roller 115. As a result, the medium waiting in the separation section vibrates as it repeatedly moves forward and backward, and the leading edge of the medium rises, making it easy for the medium to buckle or jam. In addition, a downward force is applied to the separation roller 115 by the pick roller 113 and the feed roller 114 through the medium waiting in the separation section. When a force to rotate in the opposite direction A13 to the medium feeding direction is applied to the separation roller 115, which is supported by the arm 115a so as to be swingable in the opposite direction A13 to the medium feeding direction, a downward moment acts on the separation roller 115, and the force pressing the separation roller 115 downward increases. This downward pushing force and the upward urging force from the urging member via arm 115a cause separation roller 115 to vibrate in height direction A1, making it easier for media to be fed in multiples (sloshing to the downstream side of the separation section).To address this, medium feeding device 100 holds separation roller 115 immediately after starting to feed the media, thereby preventing media jams and multiple feeds from occurring.

[0072] 8(A) to (C) and 9(A) to (C) are schematic diagrams for explaining the feeding of a medium.

[0073] Fig. 8(A) shows the state of each roller immediately after the medium feeding starts. As shown in Fig. 8(A), immediately after the medium feeding starts, the pick roller 113, the feed roller 114, and the first transport roller 122a are controlled to rotate in the medium feeding directions A11, A12, and A14, respectively, and the separation roller 115 is controlled to rotate in the opposite direction A13 to the medium feeding direction. However, due to the action of a torque limiter provided on the separation roller 115, the driving force from the second motor 142 is cut off, and the separation roller 115 does not rotate according to the driving force from the second motor 142, but rotates in the medium feeding direction A13' following the feed roller 114.

[0074] Next, control unit 161 waits until second medium sensor 117 detects the leading edge of the medium (step S105). Control unit 161 periodically acquires a second medium signal from second medium sensor 117, and determines that second medium sensor 117 has detected the leading edge of the medium when the signal value of the second medium signal changes from a value indicating that no medium is present to a value indicating that a medium is present.

[0075] Next, the control unit 161 controls the third motor 143 to stop the pick roller 113 (step S106). That is, when the second medium sensor 117 detects the leading end of the preceding medium, the control unit 161 stops the pick roller 113.

[0076] FIG. 8B shows a state in which the leading edge of the medium M1 to be fed, which is arranged at the top, has passed through the separation section. As shown in FIG. 8B, when the leading edge of the medium M1 has passed through the separation section, the control unit 161 stops the pick roller 113. At this time, only the medium M1 is present between the feed roller 114 and the separation roller 115. Due to the action of the torque limiter provided on the separation roller 115, the driving force from the second motor 142 is cut off, and the separation roller 115 is rotated in the medium feed direction A13' following the feed roller 114. The medium M1 is moved toward the downstream side by the feed roller 114 and the separation roller 115 which is rotated in the medium feed direction A11 following the feed roller 114. Therefore, the first encoder 112 continues to rotate in the medium feed direction A11.

[0077] Next, control unit 161 determines whether fourth medium sensor 124 has detected the leading edge of the medium (step S107). Control unit 161 periodically acquires a fourth medium signal from fourth medium sensor 124, and determines that fourth medium sensor 124 has detected the leading edge of the medium when the signal value of the fourth medium signal changes from a value indicating that no medium is present to a value indicating that a medium is present.

[0078] If the fourth medium sensor 124 has not yet detected the leading edge of the medium, the control unit 161 determines whether the separation roller 115 is stopped or rotating in the opposite direction A13 to the medium feeding direction (step S108). The control unit 161 periodically receives a rotation signal from the second encoder 116. The control unit 161 determines whether the separation roller 115 is stopped or rotating in the opposite direction A13 to the medium feeding direction based on the rotation direction indicated by the signal value of the received rotation signal.

[0079] The control unit 161 may further determine that the separation roller 115 is rotating in the opposite direction A13 to the medium feeding direction only when the moving distance indicated by the signal value of the received rotation signal, i.e., the moving distance of the outer circumferential surface of the separation roller 115, is equal to or greater than a predetermined distance. In this case, the control unit 161 determines that the separation roller 115 is rotating in the opposite direction A13 to the medium feeding direction only when the total moving distance when the signal value of the rotation signal indicates that the separation roller 115 is rotating in the opposite direction A13 to the medium feeding direction is equal to or greater than a predetermined distance. This makes it possible to prevent the control unit 161 from erroneously determining that the leading edge of the medium following the medium to be fed has reached the separation unit when the separation roller 115 rotates in the opposite direction A13 to the medium feeding direction with a slight slip. If the separation roller 115 is not rotating in the opposite direction A13 to the medium feeding direction, the control unit 161 does not execute any particular process and moves to step S110.

[0080] On the other hand, when the separation roller 115 is rotating in the direction A13 opposite to the medium feeding direction, the control unit 161 determines that the leading edge of the medium following the medium to be fed has reached the separation unit, and sets the arrival flag to ON (step S109).

[0081] Next, control unit 161 determines whether a predetermined time has elapsed since the start of feeding of the medium (step S110). The predetermined time is preset to a time that is the time required for the leading edge of the medium to move from the position at the downstream end of mounting table 103 to the position of fourth medium sensor 124, plus a margin. If the predetermined time has not elapsed since the start of feeding of the medium, control unit 161 returns the process to step S107 without performing any particular process.

[0082] On the other hand, if a predetermined time has elapsed since the start of feeding the medium, the control unit 161 determines that the medium has not been transported to the position of the first transport roller 122a within the predetermined time and that a medium jam has occurred, and sets the jam flag to ON (step S111).

[0083] On the other hand, if the fourth medium sensor 124 detects the leading edge of the medium in step S107, the control unit 161 controls the first motor 141 to stop the feed roller 114 (step S112). Thereafter, the medium is transported by the first transport roller 122a and the first driven roller 123a. By stopping the feed roller 114 after the medium has passed the position of the first transport roller 122a, the control unit 161 can prevent the medium from being pushed out by the feed roller 114 and bending, or from being pulled by the feed roller 114 and being damaged.

[0084] Next, the control unit 161 waits until the first encoder 112 detects the rear end of the medium (step S113). The control unit 161 periodically acquires a distance signal from the first encoder 112, and determines that the first encoder 112 has detected the rear end of the medium when the signal value of the distance signal changes from a value indicating that the medium is moving to a value indicating that the medium is not moving.

[0085] 8C shows a state in which the rear end of the medium M1 to be fed, which is arranged at the top, has passed the position of the first encoder 112. As shown in FIG. 8C, when the rear end of the medium M1 has passed the position of the first encoder 112, the first encoder 112 moves away from the medium M1 and comes into contact with the medium M2 arranged below the medium M1. At this time, the pick roller 113 and the feed roller 114 are stopped, and the medium M2 is not being fed (is not moving), so the first encoder 112 stops. By detecting that the first encoder 112 has stopped, the control unit 161 can detect that the rear end of the medium M1 being fed has passed the position of the first encoder 112.

[0086] Next, the detection unit 162 detects the size of the medium (step S114). The detection unit 162 detects the size of the preceding medium to be fed in the medium transport direction A2 based on the drive amount of the first motor 141 from when the leading edge of the medium passes the position of the second medium sensor 117 until the trailing edge of the medium passes the position of the first encoder 112. The detection unit 162 detects the sum of the movement distance of the outer circumferential surface of the feed roller 114 when the first motor 141 is driven by the above drive amount and the distance between the second medium sensor 117 and the first encoder 112 as the size of the medium. The detection unit 162 may determine whether the size of the medium is less than the predetermined size based on whether the trailing edge of the medium passes the position of the first encoder 112 while the leading edge of the medium advances a predetermined distance (for example, 60 mm) after passing the position of the second medium sensor 117. The predetermined size is the sum of the predetermined distance and the distance between the second medium sensor 117 and the first encoder 112. The predetermined size is set to, for example, the length in the longitudinal direction of an A7 size or the length in the longitudinal direction of an A8 size.

[0087] Next, the control unit 161 determines whether the size of the preceding medium detected by the detection unit 162 is less than a predetermined size (step S115). If the size of the preceding medium is less than the predetermined size, the control unit 161 proceeds to step S120 without executing the processes of steps S117 to S119. In other words, if the size of the preceding medium is less than the predetermined size, the control unit 161 does not re-rotate the pick roller 113 when the first encoder 112 detects the rear end of the preceding medium.

[0088] Since small media can be fed with a small force, it is highly likely that the media that are not in contact with the pick roller 113 and are arranged below the medium to be fed are also transported to the front of the nip of the separation section before feeding. The media that are transported to the front of the nip of the separation section before feeding are fed (pass through the separation section) in a short time. Therefore, when feeding small media, it is highly likely that the medium feeding device 100 can feed the following medium in a sufficiently short time even if the medium feeding device 100 does not start feeding the following medium before the rear end of the preceding medium passes through the separation section. In addition, since small media are light, if the leading edge of the following medium hits the nip of the separation section during the separation of the preceding medium, a medium jam may occur. In general, when multiple media are fed together, the sizes of the media are highly likely to be the same. When the preceding medium is a small medium, the control unit 161 does not start feeding the following medium before the rear end of the preceding medium passes through the separation unit, thereby allowing the following medium to be fed in a sufficiently short time while reducing the possibility of the medium jamming.

[0089] If the size of the preceding medium is equal to or larger than the predetermined size, the control unit 161 determines whether any of the arrival flag, jam flag, and skew flag is set to ON (step S116). If any of the arrival flag, jam flag, and skew flag is set to ON, the control unit 161 proceeds to step S120.

[0090] When the arrival flag is set to ON, that is, when the leading edge of the trailing medium has reached the nip portion of the separation portion, the control unit 161 does not re-rotate the pick roller 113 when the first encoder 112 detects the trailing edge of the leading medium. In other words, when the second encoder 116 detects that the separation roller 115 has stopped or is rotating in the direction A13 opposite to the medium feeding direction, the control unit 161 does not re-rotate the pick roller 113 when the first encoder 112 detects the trailing edge of the leading medium. This allows the control unit 161 to prevent the trailing medium M2 from being pushed out too far by the pick roller 113, causing double feeding, buckling, or jamming of the media.

[0091] When the jam flag is set to ON, that is, when a jam has occurred on the preceding medium, the control unit 161 does not re-rotate the pick roller 113 when the first encoder 112 detects the rear end of the preceding medium. This allows the control unit 161 to prevent a jam of the following medium from occurring following a jam of the preceding medium, causing damage to the medium.

[0092] When the skew flag is set to ON, that is, when skew of the preceding medium occurs, the control unit 161 does not re-rotate the pick roller 113 when the first encoder 112 detects the rear end of the preceding medium. This allows the control unit 161 to prevent the following medium from reaching the separation unit and hindering the correction of the skew of the medium by the feed roller 114.

[0093] On the other hand, if the arrival flag, jam flag, and skew flag are all set to OFF, the control unit 161 controls the third motor 143 to re-rotate the pick roller 113 (step S117). That is, when the first encoder 112 detects the rear end of the leading medium, the control unit 161 re-rotates the pick roller 113 to advance the trailing medium.

[0094] Fig. 9(A) shows the state after the rear end of the medium M1 to be fed, which is arranged at the top, has passed the position of the first encoder 112. As shown in Fig. 9(A), when the rear end of the medium M1 has passed the position of the first encoder 112 (before passing through the separation section), the pick roller 113 rotates again, and the following medium M2 advances toward the separation section together with the preceding medium M1. The control unit 161 advances the following medium M2 toward the separation section before the rear end of the preceding medium M1 passes through the separation section, thereby enabling the following medium M2 to be fed in a shorter time.

[0095] The control unit 161 sets the rotation speed of the pick roller 113 when the first encoder 112 detects the rear end of the leading medium to a speed lower than the rotation speed at which the pick roller 113 is rotated when feeding of the leading medium begins. By lowering the advancing speed of the trailing medium, the control unit 161 can prevent the leading end of the trailing medium from strongly colliding with the separation unit during feeding of the leading medium, causing a medium jam. Note that the control unit 161 may set the rotation speed of the pick roller 113 when the first encoder 112 detects the rear end of the medium to the same speed as the rotation speed of the pick roller 113 when feeding of the medium begins.

[0096] Next, the control unit 161 waits until the second encoder 116 detects that the separation roller 115 has stopped or is rotating in the opposite direction A13 to the medium feeding direction, or until the third motor 143 is rotated a predetermined amount after the pick roller 113 starts rotating again (step S118). The predetermined amount is determined in advance through a previous experiment as the amount of rotation required to move the medium from the downstream end of the mounting table 103 to the nip part of the separation unit. The control unit 161 determines whether the separation roller 115 has stopped or is rotating in the opposite direction A13 to the medium feeding direction, in the same manner as in the process of step S108.

[0097] Next, the control unit 161 controls the third motor 143 to stop the pick roller 113 again (step S119). That is, after the control unit 161 has restarted the rotation of the pick roller 113, when the second encoder 116 detects that the separation roller 115 has stopped or has rotated in the opposite direction A13 to the medium feeding direction, the control unit 161 stops the pick roller 113 again to stop the progress of the subsequent medium.

[0098] FIG. 9(B) shows a state in which the leading edge of the trailing medium M2 reaches the separation section from the state shown in FIG. 9(A). As shown in FIG. 9(B), when the leading edge of the medium M2 reaches the separation section, two media, the leading medium M1 and the trailing medium M2, are present between the feed roller 114 and the separation roller 115. Therefore, the separation driving force from the second motor 142 is transmitted to the separation roller 115, and the separation roller 115 stops or rotates in the opposite direction A13 to the medium feeding direction. The control unit 161 stops the pick roller 113 again at this timing to stop the progress of the trailing medium M2, thereby making it possible for the trailing medium M2 to wait in front of the separation section. Therefore, the medium feeding device 100 can feed the trailing medium M2 in a shorter time after the feeding of the leading medium M1 is completed.

[0099] In this way, when the second encoder 116 detects that the separation roller 115 has stopped or is rotating in the opposite direction A13 to the medium feeding direction, the control unit 161 stops the pick roller 113 again. By using the second encoder 116 to monitor the rotation of the separation roller 115, the control unit 161 can instantly and reliably detect that the following medium M2 has reached the separation unit. This allows the control unit 161 to prevent the following medium M2 from being pushed out too far by the pick roller 113, causing double feeding, buckling, or jamming of the media.

[0100] Furthermore, when the third motor 143 has rotated a predetermined amount since the start of re-rotation of the pick roller 113, that is, when a predetermined time has elapsed, the control unit 161 re-rotates the pick roller 113. By monitoring the rotation amount (or elapsed time) of the third motor 143, the control unit 161 can appropriately stop the trailing medium M2 even if the separation roller 115 is rotating along with the medium even though the trailing medium M2 has reached the separation unit.

[0101] Next, the control unit 161 waits until the second medium sensor 117 detects the rear end of the medium (step S120). The control unit 161 periodically acquires a second medium signal from the second medium sensor 117, and determines that the second medium sensor 117 has detected the rear end of the medium when the signal value of the second medium signal changes from a value indicating a state in which the medium is present to a value indicating a state in which the medium is not present. The control unit 161 determines whether the rear end of the medium being fed has passed through the nip portion of the feed roller 114 and the separation roller 115 by determining whether the second medium sensor 117 has detected the rear end of the medium. That is, the control unit 161 determines whether the rear end of the preceding medium M1 has passed through the feed roller 114 and the separation roller 115 after stopping the pick roller 113 again.

[0102] Next, control unit 161 determines whether or not media remain on mounting table 103 based on the medium signal received from first medium sensor 111 (step S121). If media remain on mounting table 103, control unit 161 returns the process to step S103 and repeats the processes from step S103 onwards. Each time control unit 161 repeats the processes of steps S103 to S121, it causes the multiple media placed on mounting table 103 to be fed in sequence.

[0103] In this case, in step S104, the control unit 161 drives the third motor 143 and the first motor 141 to rotate the pick roller 113 and the feed roller 114 in the medium feed directions A11 and A12, respectively, to feed the medium placed on the placement table 103. That is, when the rear end of the preceding medium M1 passes the feed roller 114 and the separation roller 115, the control unit 161 re-rotates the pick roller 113 to feed the following medium M2.

[0104] Fig. 9(C) shows a state in which the rear end of the leading medium M1 has passed through the separation section from the state shown in Fig. 9(B). As shown in Fig. 9(C), when the rear end of the leading medium M1 has passed through the separation section, the control unit 161 rotates the pick roller 113 and the feed roller 114 again to feed the trailing medium M2. This allows the control unit 161 to separate the trailing medium M2 from the leading medium M1, and feed the trailing medium M2 in a shorter time while maintaining an appropriate distance between the trailing medium M2 and the leading medium M1.

[0105] The control unit 161 sets the rotation speed of the pick roller 113 when the pick roller 113 is rotated again when the trailing end of the preceding medium passes the feed roller 114 and the separation roller 115 to a speed higher than the rotation speed of the pick roller 113 when the pick roller 113 is rotated again in step S117 when the first encoder 112 detects the trailing end of the preceding medium. The control unit 161 increases the advancement speed of the following medium when the feeding of the preceding medium is completed, thereby reducing the time required for feeding the following medium and reducing the time required for the medium conveying process. The control unit 161 may set the rotation speed of the pick roller 113 when the trailing end of the medium passes the feed roller 114 and the separation roller 115 to the same speed as the rotation speed of the pick roller 113 when the first encoder 112 detects the trailing end of the medium.

[0106] On the other hand, if there are no media remaining on the placement table 103, the control unit 161 controls the second motor 142 to stop the separation roller 115, and controls the third motor 143 to stop the first to sixth transport rollers 122a-f (step S122). Then, the control unit 161 ends the series of steps.

[0107] When the feeding mode is set to the non-separation mode, the processes of steps S103, S108 to S111, and S113 to S121 are omitted. In this case, in step S105, the control unit 161 controls the separation roller 115 to rotate in a driven manner with the feeding roller 114.

[0108] The processes in steps S108 to S109, S110 to S111, or S114 to S115 may be omitted.

[0109] The control unit 161 may also receive a setting from the user as to whether or not to start feeding the following medium before the rear end of the preceding medium passes through the separation unit. In this case, the control unit 161 receives the setting input by the user using the operation unit 105 or the information processing device from the operation unit 105 or the interface unit 144. When it is set that feeding of the following medium is not to start before the rear end of the preceding medium passes through the separation unit, the control unit 161 omits the processes of steps S108 to S111 and S113 to S119. The user can select which of reducing the time required for the medium transport process and preventing the occurrence of double feeding of media is to be prioritized according to the application or type of medium, and the medium feeding device 100 can improve the convenience for the user.

[0110] Furthermore, when it is detected in step S108 or S118 that the separation roller 115 is stopped or rotating in the direction A13 opposite to the medium feeding direction, the control unit 161 may change the pressure with which the separation roller 115 presses the feed roller 114. For example, the control unit 161 controls the third motor 143 to increase the pressure with which the separation roller 115 presses the feed roller 114. This allows the control unit 161 to increase the frictional force generated between the trailing medium and the separation roller 115, thereby preventing the trailing medium from being fed to the downstream side of the separation unit.

[0111] In that case, after the second medium sensor 117 detects the rear end of the medium in step S120, in step S104, the control unit 161 may reduce the pressing force with which the separation roller 115 presses the feed roller 114. For example, the control unit 161 controls the third motor 143 to reduce the pressing force with which the separation roller 115 presses the feed roller 114. In this way, the control unit 161 can increase the medium separation force of the feed roller 114 and the separation roller 115, thereby preventing the occurrence of double feeding of media.

[0112] FIG. 10 is a flowchart showing an example of the operation of the skew determination process of the medium feeding device 100.

[0113] An example of the operation of the skew determination process of the medium feeding device 100 will be described below with reference to the flowchart shown in Fig. 10. The flow of the operation described below is executed mainly by the processing circuit 160 in cooperation with each element of the medium feeding device 100 based on a program previously stored in the storage device 150. The flow of the operation shown in Fig. 10 is executed periodically during medium transport.

[0114] First, skew determining unit 163 receives a first skew signal and a second skew signal from first skew sensor 119 and second skew sensor 120, respectively, and stores each signal value of each received skew signal in storage device 150 (step S201).

[0115] Next, the skew determination unit 163 determines whether the skew condition is satisfied (step S202). The skew determination unit 163 determines whether the leading edge of the medium has reached each of the positions of the first skew sensor 119 and the second skew sensor 120. The skew determination unit 163 determines that the leading edge of the medium has reached the position of the first skew sensor 119 when the signal value of the first skew signal changes from a value indicating that the medium is not present to a value indicating that the medium is present. The skew determination unit 163 also determines that the leading edge of the medium has reached the position of the second skew sensor 120 when the signal value of the second skew signal changes from a value indicating that the medium is not present to a value indicating that the medium is present. The skew determination unit 163 determines that the skew condition is satisfied when the leading edge of the medium has reached one of the positions of the first skew sensor 119 and the second skew sensor 120 and has not reached the other position within a third predetermined time. The third specified time is set, for example, to the average, median, minimum or maximum value of the difference in the time at which the medium passes through each skew sensor when a medium jam occurs or a portion of the medium is missing in the input image, based on a prior experiment in which the medium is transported at an angle.

[0116] If the skew condition is not satisfied, the skew determining unit 163 determines that the medium skew has not occurred (step S203) and ends the series of steps. On the other hand, if the skew condition is satisfied, the skew determining unit 163 determines that the medium skew has occurred (step S204).

[0117] Next, the control unit 161 controls the multiple feed rollers 114 to correct the skew of the medium when the skew of the medium occurs (step S205). The control unit 161 corrects the skew of the medium by making the circumferential speeds of the feed rollers 114 different from one another. The control unit 161 changes the circumferential speed of each feed roller 114 so that the circumferential speed of the feed roller 114 arranged on the side where the progress of the medium is delayed in the width direction A4 is faster (higher) than the circumferential speed of the feed roller 114 arranged on the side where the progress of the medium is leading. The control unit 161 speeds up (increases) the circumferential speed of the feed roller 114 arranged on the side where the progress of the medium is lagging and / or slows down (decreases) the circumferential speed of the feed roller 114 arranged on the leading side.

[0118] Next, the skew determining unit 163 sets the skew flag to ON (step S206), and ends the series of steps.

[0119] 7, when the skew flag is set to ON, the control unit 161 does not re-rotate the pick roller 113 when the first encoder 112 detects the rear end of the preceding medium. This enables the control unit 161 to prevent the following medium from reaching the separation unit and hindering the correction of the skew of the preceding medium.

[0120] FIG. 11 is a flowchart showing an example of the operation of the attachment determination process of the medium feeding device 100.

[0121] An example of the operation of the attachment determination process of the medium feeding device 100 will be described below with reference to the flowchart shown in Fig. 11. The flow of the operation described below is executed mainly by the processing circuit 160 in cooperation with each element of the medium feeding device 100 based on a program previously stored in the storage device 150. The flow of the operation shown in Fig. 11 is executed periodically during medium transport.

[0122] First, the attachment determination unit 164 acquires an ultrasonic signal from the ultrasonic sensor 121 (step S301). Next, the attachment determination unit 164 determines whether the signal value of the acquired ultrasonic signal is equal to or greater than an overlap threshold (step S302). The overlap threshold is set to a value between the signal value of the ultrasonic signal when one sheet of paper is being conveyed and the signal value of the ultrasonic signal when overlapped paper feed occurs.

[0123] When the signal value of the ultrasonic signal is equal to or greater than the overlap threshold, the attachment determination unit 164 does not execute any particular process and ends the series of steps. On the other hand, when the signal value of the ultrasonic signal is less than the overlap threshold, the attachment determination unit 164 determines that a sticker such as a sticky note or a label (seal) is attached to the medium (step S303). Next, the attachment determination unit 164 notifies the user by transmitting information indicating that a sticker is attached to the medium via the interface device 144 to the information processing device (step S304), and ends the series of steps. On the other hand, when the signal value of the ultrasonic signal does not become less than the overlap threshold before the rear end of the medium passes the ultrasonic sensor 121, the attachment determination unit 164 determines that no sticker is attached to the medium.

[0124] In this way, the attachment determination unit 164 determines whether or not a sticker is attached to the medium based on the ultrasonic signal. During feeding of the medium, the feeding roller 114 is stopped in step S112 of FIG. 7. Also, if a duplicated medium feed occurs, the separation roller 115 is stopped or rotates in the direction A13 opposite to the medium feeding direction in step S118 of FIG. 7, and the pick roller 113 is stopped. Therefore, if an overlap of media is detected by the ultrasonic sensor 121 arranged downstream of the separation unit, it is unlikely that a duplicated medium feed occurs. Therefore, the medium feeding device 100 can identify that a sticker is attached to the medium when an overlap of media is detected by the ultrasonic sensor 121 arranged downstream of the separation unit.

[0125] FIG. 12 is a flowchart showing an example of the operation of the image acquisition process of the medium feeding device 100.

[0126] An example of the operation of the skew determination process of the medium feeding device 100 will be described below with reference to the flowchart shown in Fig. 12. The flow of the operation described below is executed mainly by the processing circuit 160 in cooperation with each element of the medium feeding device 100 based on a program previously stored in the storage device 150. The flow of the operation shown in Fig. 12 is executed periodically during medium transport.

[0127] First, control unit 161 waits until fourth medium sensor 124 detects the leading edge of the medium (step S401). Control unit 161 periodically acquires a fourth medium signal from fourth medium sensor 124, and determines that fourth medium sensor 124 has detected the leading edge of the medium when the signal value of the fourth medium signal changes from a value indicating that no medium is present to a value indicating that a medium is present.

[0128] Next, the control unit 161 causes the imaging device 125 to start imaging (step S402).

[0129] Next, control unit 161 waits until the rear end of the medium passes the imaging position (step S403). For example, control unit 161 periodically acquires a fourth medium signal from fourth medium sensor 124, and determines that fourth medium sensor 124 has detected the rear end of the medium when the signal value of the fourth medium signal changes from a value indicating a state in which the medium is present to a value indicating a state in which the medium is not present. Control unit 161 determines that the rear end of the medium has passed the imaging position when a second predetermined time has elapsed since fourth medium sensor 124 detected the rear end of the medium. The second predetermined time is set to the time it takes for the medium to move from fourth medium sensor 124 to the imaging position plus a margin.

[0130] Next, the control unit 161 causes the imaging device 125 to end imaging. The control unit 161 acquires an input image from the imaging device 125, and outputs the acquired input image by transmitting it to the information processing device via the interface device 144 (step S404), thereby completing the series of steps.

[0131] As described above in detail, the medium feeding device 100 temporarily stops the pick roller 113 when the leading edge of the leading medium passes through the separation section. The medium feeding device 100 resumes the rotation of the pick roller 113 when the trailing edge of the leading medium passes through the pick roller 113, and advances the next medium until the leading edge of the trailing medium reaches the separation section. This allows the medium feeding device 100 to promptly start feeding the trailing medium when the trailing edge of the leading medium passes through the separation section, while maintaining an appropriate distance between the trailing edge of the leading medium and the leading edge of the trailing medium. Therefore, the medium feeding device 100 can reduce the time required to feed the medium while suppressing the occurrence of double feeding of the medium.

[0132] In particular, medium feeding device 100 temporarily stops pick roller 113 when the leading edge of the preceding medium passes through the separation section. This prevents pick roller 113 from contacting the medium further below through the hole and feeding the medium below when a hole such as a punch hole is formed in the medium placed below the preceding medium. Furthermore, medium feeding device 100 can reduce unnecessary power consumption of medium feeding device 100 by temporarily stopping pick roller 113 when the leading edge of the preceding medium passes through the separation section.

[0133] In general, the degree to which the leading medium draws in the trailing medium changes depending on the type or condition of the medium, or the environment in which the medium feeding device 100 is installed. For example, when the coefficient of friction between the media is low, the degree to which the leading medium draws in the trailing medium is low, and when the trailing end of the leading medium passes through the separation section, the leading edge of the trailing medium is located at a position away from the separation section. On the other hand, when the coefficient of friction between the media is high, the degree to which the leading medium draws in the trailing medium is high, and when the trailing end of the leading medium passes through the separation section, the leading edge of the trailing medium is located at a position close to the separation section. When the trailing end of the leading medium passes through the pick roller 113, the medium feeding device 100 resumes rotation of the pick roller 113, and advances the next medium until the leading edge of the trailing medium reaches the separation section. As a result, the medium feeding device 100 can have the leading end of the trailing medium wait in front of the nip portion of the separation section when the trailing end of the leading medium has passed through the separation section, regardless of the type or condition of the medium or the environment in which the medium feeding device 100 is installed.

[0134] Furthermore, even if the leading edges of media set together on the mounting table 103 by a user are not aligned, the medium feeding device 100 can make the leading edge of the following medium wait in front of the nip section of the separation section when the trailing edge of the preceding medium passes through the separation section. The user no longer needs to carefully align the media when setting multiple media together on the mounting table 103, and the medium feeding device 100 can improve user convenience.

[0135] Furthermore, medium feeding device 100 can reduce the time required to feed a medium without increasing the feeding speed or transport speed of the medium. Therefore, medium feeding device 100 can reduce the time required to feed a medium while suppressing an increase in parts cost due to the use of high-spec parts, an increase in replacement part costs due to reduced part durability, or an increase in device power consumption.

[0136] Furthermore, medium feeding device 100 does not use an ultrasonic sensor or a thickness sensor, but uses second encoder 116 that detects the rotation of separation roller 115 to determine whether the leading edge of the subsequent medium has reached the position of separation roller 115. Therefore, even if a sticker is affixed to the preceding medium, medium feeding device 100 does not erroneously determine that the leading edge of the subsequent medium has reached the position of separation roller 115, and can determine with high accuracy whether the leading edge of the subsequent medium has reached the position of separation roller 115.

[0137] FIG. 13 is a diagram showing a schematic configuration of a processing circuit 260 of a medium feeding device according to another embodiment.

[0138] The processing circuit 260 is used in place of the processing circuit 160 of the medium feeding device 100, and executes the medium reading process and the like in place of the processing circuit 160. The processing circuit 260 has a control circuit 261, a detection circuit 262, a skew determination circuit 263, and an attachment determination circuit 264. Each of these components may be composed of an independent integrated circuit, microprocessor, firmware, or the like.

[0139] The control circuit 261 is an example of a control unit, and has the same functions as the control unit 161. The control circuit 261 receives an operation signal from the operation device 105 or the interface device 144. The control circuit 261 also receives a first medium signal, a second medium signal, a third medium signal, and a fourth medium signal from the first medium sensor 111, the second medium sensor 117, the third medium sensor 118, and the fourth medium sensor 124, respectively. The control circuit 261 also receives a distance signal and a rotation signal from the first encoder 112 and the second encoder 116, respectively. The control circuit 261 also reads out the skew determination result and the medium size detection result from the storage device 150. The control circuit 261 controls the first motor 141, the second motor 142, and the third motor 143 based on each received signal and / or each read information. The control circuit 261 also obtains an input image from the imaging device 125, and outputs it to the interface device 144.

[0140] The detection circuit 262 is an example of a detection unit, and has the same function as the detection unit 162. The detection circuit 262 receives a distance signal and a fourth medium signal from the first encoder 112 and the fourth medium sensor 124, respectively. The detection circuit 262 detects the size of the medium based on the received signals, and stores the detection result in the storage device 150.

[0141] The skew determination circuit 263 is an example of a skew determination section, and has the same function as the skew determination section 163. The skew determination circuit 263 receives a first skew signal and a second skew signal from the first skew sensor 119 and the second skew sensor 120, respectively. The skew determination circuit 263 determines whether or not a skew of the medium has occurred based on the received signals, and stores the determination result in the storage device 150.

[0142] The attachment determination circuit 264 is an example of an attachment determination section, and has the same function as the attachment determination section 164. The attachment determination circuit 264 receives an ultrasonic signal from the ultrasonic sensor 121. The attachment determination circuit 264 determines whether or not a sticker is attached to the medium based on the received ultrasonic signal, and outputs a warning to the interface device 144 according to the determination result.

[0143] As described above in detail, the medium feeding device is now able to more appropriately feed the medium even when the processing circuit 260 is used.

[0144] Although preferred embodiments have been described above, the embodiments are not limited thereto. For example, the medium feeding device 100 may use another sensor instead of the second encoder 116 to determine whether the leading edge of the following medium has reached the separation section. For example, the medium feeding device 100 uses an ultrasonic sensor to determine whether the leading edge of the following medium has reached the separation section. In this case, an ultrasonic sensor similar to the ultrasonic sensor 121 is disposed at a position overlapping the nip portion of the feed roller 114 and the separation roller 115 as viewed from the width direction A4. In step S108 or S118, the control unit 161 receives an ultrasonic signal from the ultrasonic sensor, and determines that the leading edge of the following medium has reached the separation section when the signal value of the received ultrasonic signal is less than the overlap threshold value.

[0145] Alternatively, the medium feeding device 100 may determine whether the leading edge of the following medium has reached the separation section based on the amount of current flowing through the second motor 142. In this case, a DC (Direct Current) motor is used as the second motor 142. Although a DC motor is low-cost and allows easy speed adjustment, the rotation speed of the DC motor varies depending on external factors such as load fluctuation. The lower the rotation speed of the motor, the greater the torque of the motor, and the greater the torque of the motor, the greater the amount of current flowing through the motor. In step S108 or S118, the control unit 161 receives the amount of current flowing through the second motor 142 from the second motor 142, and determines that the leading edge of the following medium has reached the separation section if the received amount of current is equal to or greater than the current threshold. The current threshold is set to the average, median, minimum, or maximum amount of current flowing through the DC motor when reverse rotation of the DC motor occurs, based on a prior experiment.

[0146] Alternatively, the medium feeding device 100 may use an optical sensor to determine whether the leading edge of the following medium has reached the separation section. In this case, the optical sensor is disposed so as to image from below the area of ​​the medium being fed that overlaps with the nip portion of the feeding roller 114 and the separation roller 115 as viewed from the width direction A4. The optical sensor has a light emitter and a light receiver provided on the same side of the medium transport path, and detects the movement of the medium in the medium transport direction A2 and the width direction A4. The light emitter is an LED or the like, and emits light toward the transport path. The light receiver captures an image according to the light received at regular intervals, and detects a common portion between the latest image and the image immediately before. The light receiver calculates the movement direction and movement speed of the transported medium based on the change in position of the detected common portion in the image, and generates and outputs a movement signal indicating the calculated movement direction and movement speed. The regular period is, for example, a period corresponding to 100 operating pulses of the second motor 142. In step S108 or S118, the control unit 161 receives a movement signal from the optical sensor, and if the signal value of the received movement signal indicates that the medium is moving from the upstream side to the downstream side, it determines that the leading edge of the trailing medium has reached the separation section.

[0147] Similarly, the medium feeding device 100 may use another sensor instead of the first encoder 112 to determine whether the trailing end of the preceding medium has passed the position of the pick roller 113. For example, the medium feeding device 100 uses an optical sensor to determine whether the trailing end of the preceding medium has passed the position of the pick roller 113. In this case, the optical sensor is disposed so as to capture an image from above of an area of ​​the medium placed on the placement table 103 that overlaps with the nip portion of the pick roller 113 when viewed from the width direction A4. In step S113, the control unit 161 receives a movement signal from the optical sensor, and determines that the trailing end of the preceding medium has passed the position of the pick roller 113 when the signal value of the received movement signal does not indicate that the medium is moving from the upstream side to the downstream side.

[0148] Furthermore, when the medium feeding device 100 uses the second encoder 116 to determine whether the leading edge of the following medium has reached the separation unit, the second encoder 116 may be used to execute other functions. For example, the control unit 161 acquires a rotation signal from the second encoder 116 while controlling the second motor 142 to rotate the separation roller 115 at the start of the medium feeding device 100. If the signal value of the rotation signal indicates that the separation roller 115 is not rotating, the control unit 161 determines that the separation roller 115 has failed to be attached or has been forgotten to be attached, or that a malfunction has occurred in the separation roller 115 or the second encoder 116. Furthermore, the control unit 161 acquires a rotation signal from the second encoder 116 while controlling the first motor 141 to rotate the feed roller 114 at the start of the medium feeding device 100. When the signal value of the rotation signal indicates that the separation roller 115 is not rotating, the control unit 161 determines that the surface of the feed roller 114 or the separation roller 115 is dirty and that the frictional force between the feed roller 114 and the separation roller 115 is reduced. In these cases, the control unit 161 notifies the user of the warning by transmitting information indicating the warning to the information processing device via the interface device 144.

[0149] The control unit 161 may also determine whether the following medium has reached the separation unit when the preceding medium to be fed has passed through the separation unit based on the rotation signal from the second encoder 116. If the following medium has not reached the separation unit while the preceding medium is passing through the separation unit, the separation roller 115 rotates in the medium feeding direction following the feeding roller 114. On the other hand, if the following medium has reached the separation unit while the preceding medium is passing through the separation unit, the separation roller 115 is stopped or rotating in the opposite direction A13 to the medium feeding direction. Therefore, when the signal value of the rotation signal indicates that the separation roller 115 is rotating in the medium feeding direction, the control unit 161 determines that the following medium has not reached the separation unit. On the other hand, when the signal value of the rotation signal indicates that the separation roller 115 is stopped or rotating in the opposite direction A13 to the medium feeding direction, the control unit 161 determines that the following medium has reached the separation unit. When the control unit 161 determines that the following medium has reached the separation unit when the preceding medium to be fed has passed the separation unit, it delays, for example, the timing of feeding by the feeding roller 114 and the pick roller 113. In this way, the control unit 161 can sufficiently increase the distance between the two media fed in succession to prevent collisions between the media or image defects in the input image. [Explanation of symbols]

[0150] 100 medium feeding device, 103 placement table, 112 first encoder, 113 pick roller, 114 feeding roller, 115 separation roller, 116 second encoder, 117 second medium sensor, 161 control unit, 162 detection unit

Claims

1. A placement table, A feeding roller for feeding a medium, A separation roller disposed opposite to the feeding roller, A pick-up roller disposed upstream of the feeding roller and the separation roller in the medium conveyance direction, A first sensor disposed upstream of the pick-up roller in the medium conveyance direction, A second sensor disposed downstream of the feeding roller and the separation roller in the medium conveyance direction, A control unit that feeds a plurality of media placed on the placement table by rotating the pick-up roller and the feeding roller in the medium feeding direction, The control unit, When the second sensor detects the leading end of the preceding medium, stops the pick-up roller, After the first sensor detects the trailing end of the preceding medium, rotates the pick-up roller again to advance the subsequent medium, The control unit changes the timing of rotating the pick-up roller again based on whether the separation roller has stopped or reversed, whether the second sensor has detected the leading end of the preceding medium before a predetermined time has elapsed since the feeding of the preceding medium was started, whether skew has occurred in the preceding medium, or whether the size of the preceding medium is less than a predetermined size. A medium conveyance device characterized by the above.

2. Further comprising a third sensor for detecting the rotation of the separation roller, The control unit, after rotating the pick-up roller again, when the third sensor detects the stop of the separation roller or rotation in the opposite direction to the medium feeding direction, stops the pick-up roller again to stop the advancement of the subsequent medium. The medium conveyance device according to Claim 1.

3. The control unit determines whether the trailing end of the preceding medium has passed through the feeding roller and the separation roller after stopping the pick-up roller again, and when the trailing end of the preceding medium has passed through the feeding roller and the separation roller, rotates the pick-up roller again to feed the subsequent medium. The medium conveyance device according to Claim 2.

4. The control unit sets the rotation speed of the pick-up roller when rotating the pick-up roller again when the trailing end of the preceding medium has passed through the feeding roller and the separation roller to a speed higher than the rotation speed of the pick-up roller when rotating the pick-up roller again when the first sensor detects the trailing end of the preceding medium. The medium conveyance device according to Claim 3.

5. further comprising a detection unit configured to detect the size of the medium, The media conveyance device according to claim 1 or 2, wherein when the size of the preceding medium is less than a predetermined size, the control unit does not re-rotate the pick roller when the first sensor detects the trailing end of the preceding medium.

6. The media conveyance device according to claim 2, wherein when the third sensor detects the stop of the separation roller or the rotation in the direction opposite to the media feeding direction, the control unit does not re-rotate the pick roller when the first sensor detects the trailing end of the preceding medium.

7. A mounting table, A feeding roller for feeding the medium, A separation roller disposed opposite to the feeding roller, A pick roller disposed upstream of the feeding roller and the separation roller in the media conveyance direction, A first sensor disposed upstream of the pick roller in the media conveyance direction, A second sensor disposed downstream of the feeding roller and the separation roller in the media conveyance direction, and a control unit configured to feed a plurality of media placed on the mounting table by rotating the pick roller and the feeding roller in the media feeding direction. The control unit, stops the pick roller when the second sensor detects the leading end of the preceding medium, re-rotates the pick roller to advance the subsequent medium when the first sensor detects the trailing end of the preceding medium, The control unit sets the rotation speed of the pick roller when re-rotating the pick roller when the first sensor detects the trailing end of the preceding medium to a speed lower than the rotation speed when rotating the pick roller at the start of feeding of the preceding medium. A media conveyance device characterized by the above.

8. By rotating a feeding roller and a pick roller disposed upstream of the feeding roller and the separation roller disposed opposite to the feeding roller in the media feeding direction, a plurality of media placed on a mounting table are fed, The pick roller is stopped when a second sensor disposed downstream of the feeding roller and the separation roller in the media conveyance direction detects the leading end of the preceding medium, After a first sensor disposed upstream of the pick roller in the media conveyance direction detects the trailing end of the preceding medium, the pick roller is re-rotated to advance the subsequent medium. Based on whether the separation roller has stopped or reversed, whether the second sensor has detected the leading edge of the leading medium before a predetermined time has elapsed since the feeding of the leading medium was started, whether skew has occurred in the leading medium, or whether the size of the leading medium is less than a predetermined size, the timing for re-rotating the pick roller is changed. A medium feeding method characterized by the above.

9. By rotating a feeding roller and a pick roller arranged upstream of the feeding roller and a separation roller arranged opposite to the feeding roller in the medium conveying direction in the medium conveying direction, a plurality of media placed on a mounting table are fed. When a second sensor arranged downstream of the feeding roller and the separation roller in the medium conveying direction detects the leading edge of the leading medium, the pick roller is stopped. When a first sensor arranged upstream of the pick roller in the medium conveying direction detects the trailing edge of the leading medium, the pick roller is re-rotated to advance the subsequent medium. When re-rotating the pick roller when the first sensor detects the trailing edge of the leading medium, the rotation speed of the pick roller is set to a speed lower than the rotation speed at which the pick roller is rotated at the start of feeding of the leading medium. A medium feeding method characterized by the above.

10. A control program for a medium conveying device having a mounting table, a feeding roller for feeding a medium, a separation roller arranged opposite to the feeding roller, a pick roller arranged upstream of the feeding roller and the separation roller in the medium conveying direction, a first sensor arranged upstream of the pick roller in the medium conveying direction, and a second sensor arranged downstream of the feeding roller and the separation roller in the medium conveying direction, wherein: By rotating the pick roller and the feeding roller in the medium feeding direction, a plurality of media placed on the mounting table are fed. When the second sensor detects the leading edge of the leading medium, the pick roller is stopped. After the first sensor detects the trailing edge of the leading medium, the pick roller is re-rotated to advance the subsequent medium. Based on whether the separation roller has stopped or reversed, whether the second sensor has detected the leading edge of the preceding medium before a predetermined time has elapsed since the feeding of the preceding medium was started, whether skew has occurred in the preceding medium, or whether the size of the preceding medium is less than a predetermined size, change the timing for re-rotating the pick roller. A control program, characterized in that the medium conveyance device is caused to execute this. **Claim 11**: A control program for a medium conveyance device, comprising: a mounting table; a feeding roller for feeding a medium; a separation roller arranged to face the feeding roller; a pick roller arranged upstream of the feeding roller and the separation roller in the medium conveyance direction; a first sensor arranged upstream of the pick roller in the medium conveyance direction; and a second sensor arranged downstream of the feeding roller and the separation roller in the medium conveyance direction. By rotating the pick roller and the feeding roller in the medium feeding direction, feed a plurality of media placed on the mounting table. When the second sensor detects the leading edge of the preceding medium, stop the pick roller. When the first sensor detects the trailing edge of the preceding medium, re-rotate the pick roller to advance the subsequent medium. When re-rotating the pick roller when the first sensor detects the trailing edge of the preceding medium, set the rotation speed of the pick roller to a speed lower than the rotation speed at which the pick roller is rotated at the start of feeding of the preceding medium. A control program, characterized in that the medium conveyance device is caused to execute this.

Images