Medium transport device, medium transport method, and control program

Abstract

To provide a medium transport device which can determine whether or not a medium should be subject to abnormality control with higher accuracy.SOLUTION: A medium transport device includes: a pick roller; first and second lifting sensors which are respectively disposed at one side and the other side relative to the pick roller at the downstream side relative to the pick roller and detect lifting of the medium; first and second detection sensors which are respectively disposed at the same sides as the first and second lifting sensors relative to the pick roller and detect the medium; a determination unit which determines whether or not the medium is a predetermined medium based on detection results of lifting of the medium; and a control unit which executes abnormality control if it is determined that the medium is the predetermined medium. The determination unit makes the medium less likely to be determined to be the predetermined medium based on the detection result of lifting of the medium by the first lifting sensor if the one side of the medium precedes the other side.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Generally, a media conveying device such as a scanner that conveys media and captures images sequentially separates and conveys multiple media stacked on a placement table. However, if multiple media are bound with staples or the like, the media may be damaged when separating the media. Therefore, it is required for the media conveying device to appropriately detect such bound media and perform abnormality control such as stopping conveyance.

[0003] Patent Document 1 describes an image reading device that has first to third sheet detection means arranged on a medium transport path to detect the medium, and determines whether the medium is a bound medium based on the time difference between the times when each sheet detection means detects the medium. Since the bound medium is skewed when separated, it is possible to determine whether the medium is a bound medium based on the difference in detection time caused by the skew of the medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-24711 Summary of the Invention [Problem to be solved by the invention]

[0005] A medium conveying device is required to determine with high accuracy whether or not a medium is a bound medium, for which abnormality control should be executed.

[0006] An object of the present invention is to provide a medium conveying device, a control method, and a control program that are capable of determining with a high degree of accuracy whether or not abnormal control should be executed for a medium. [Means for solving the problem]

[0007] A medium transport device according to an embodiment of the present invention includes a pick roller that feeds a medium, a first lift sensor that is arranged on one side of the pick roller in the transport direction of the medium downstream of the upstream end of the nip width of the pick roller and detects lifting of the medium, a second lift sensor that is arranged on the other side of the pick roller in the transport direction downstream of the upstream end of the nip width of the pick roller and detects lifting of the medium, a first detection sensor that is arranged on the same side of the pick roller as the first lift sensor and detects the medium, a second detection sensor that is arranged on the same side of the pick roller as the second lift sensor and detects the medium, a determination unit that determines whether the medium is a specified medium based on a detection result of the lifting of the medium by the first or second lift sensor, and a control unit that executes abnormal control when it is determined that the medium is a specified medium, and is characterized in that when the first and second detection sensors detect that the first detection sensor side of the medium is leading the second detection sensor side, the determination unit makes it difficult to determine that the medium is a specified medium based on the detection result of the lifting of the medium by the first lift sensor.

[0008] A media transport method according to an embodiment of the present invention includes feeding a medium with a pick roller, detecting the floating of the medium with a first floating sensor arranged on one side of the pick roller in the transport direction downstream of the upstream end of the nip width of the pick roller, detecting the floating of the medium with a second floating sensor arranged on the other side of the pick roller in the transport direction downstream of the upstream end of the nip width of the pick roller, detecting the medium with a first detection sensor arranged on the same side of the pick roller as the first floating sensor, and detecting the medium with a second detection sensor arranged on the same side of the pick roller as the second floating sensor, determining whether the medium is a specified medium based on a detection result of the floating of the medium by the first or second floating sensor, and if it is determined that the medium is a specified medium, executing abnormality control, and is characterized in that in the determination, if the first and second detection sensors detect that the first detection sensor side of the medium is leading the second detection sensor side, it is made difficult to determine that the medium is a specified medium based on the detection result of the floating of the medium by the first floating sensor.

[0009] A control program according to an embodiment of the present invention is a control program for a medium conveying device having a pick roller that feeds a medium, a first lift sensor that is arranged on one side of the pick roller in the conveying direction of the medium downstream of the upstream end of the nip width of the pick roller and detects lifting of the medium, a second lift sensor that is arranged on the other side of the pick roller in the conveying direction downstream of the upstream end of the nip width of the pick roller and detects lifting of the medium, a first detection sensor that is arranged on the same side of the pick roller as the first lift sensor and detects the medium, and a second detection sensor that is arranged on the same side of the pick roller as the second lift sensor and detects the medium, the control program causing the medium conveying device to execute and determine whether the medium is a specified medium based on a detection result of the lifting of the medium by the first or second lift sensor, and if it is determined that the medium is a specified medium, the control program is characterized in that, when the first and second detection sensors detect that the first detection sensor side of the medium is ahead of the second detection sensor side, it becomes difficult to determine that the medium is a specified medium based on the detection result of the lifting of the medium by the first lift sensor. Effect of the Invention

[0010] The medium conveying device, the control method, and the control program according to the present invention make it possible to determine with a high degree of accuracy whether or not a medium is one for which abnormality control should be executed. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of the medium conveying device 100. [Diagram 2] 2 is a diagram showing a transport path inside the medium transport device 100. FIG. [Diagram 3] FIG. 2 is a perspective view of the floating sensor 112. [Figure 4] 1 is a diagram showing a schematic arrangement of a floating sensor 112, a second medium sensor 115, and a tilt sensor 116. FIG. [Diagram 5] 1 is a functional block diagram of a medium conveying device 100. FIG. [Figure 6] FIG. 1 is a functional block diagram of a memory device 140 and a processing circuit 150. [Figure 7] FIG. 11 is a flowchart showing the flow of a medium transport process. [Figure 8] FIG. 11 is a flowchart showing the flow of a determination process. [Figure 9] 1A is a schematic diagram of a binding medium viewed from the side, and FIG. 1B is a schematic diagram of a binding medium viewed from above. [Figure 10] 1A is a schematic diagram of a medium transported at an angle when viewed from above, and FIG. 1B is a schematic diagram of a medium transported at an angle when viewed in the transport direction A2. [Figure 11] 2 is a diagram showing a transport path inside the medium transport device 200. FIG. [Figure 12] 13 is a diagram showing a schematic arrangement of a floating sensor 112, a second medium sensor 115, and a tilt sensor 216. FIG. [Figure 13] FIG. 11 is a flowchart showing the flow of a medium transport process. [Figure 14] FIG. 3 is a functional block diagram of a processing circuit 350. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the inventions described in the claims and their equivalents.

[0013] FIG. 1 is a perspective view showing a medium conveying device 100 according to an embodiment. The medium conveying device 100 is an image scanner. The medium conveying device 100 conveys a medium, which is an original document, and captures an image of the medium. The medium is paper, cardboard, card, or the like. The medium conveying device 100 may be a facsimile, a copier, a multifunction printer (MFP, Multifunction Peripheral), or the like. The medium conveying device 100 may also be a printer or the like that conveys a medium, which is an object to be printed.

[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 transport direction A2 or discharge direction A3. In the following, upstream refers to the upstream of the transport direction A2 or discharge direction A3, and downstream refers to the downstream of the transport direction A2 or discharge direction A3.

[0015] The medium conveying 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 first housing 101 and the second housing 102 are examples of housings. The second housing 102 is disposed inside the first housing 101 and rotatably engaged with the first housing 101 by a hinge so as to be openable and closable when a jam occurs or when cleaning the inside of the medium conveying device 100.

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

[0018] A pair of side guides 103a that regulate the width of the medium are disposed on both ends in the width direction A4 of the upper surface of the mounting table 103. The side guides 103a protrude upward from the upper surface of the mounting table 103 and extend in the transport direction A2. The medium is placed between the pair of side guides 103a.

[0019] The discharge tray 104 is formed on the upper surface of the second housing 102. The discharge tray 104 has a placement surface for placing media thereon, and the media discharged from the discharge ports of the first housing 101 and the second housing 102 are placed thereon.

[0020] The operation device 105 has an input device such as a button and an interface circuit that acquires a signal from the input device. The operation equipment 105 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 that outputs image data to the display. The display device 106 displays image data on the display. The display device 106 may be a liquid crystal display with a touch panel function. In this case, the operation device 105 has an interface circuit that acquires an input signal from the touch panel.

[0021] FIG. 2 is a diagram showing a transport path inside the medium transport device 100. As shown in FIG.

[0022] The medium conveying device 100 has, on its internal conveying path, a first medium sensor 110, a pick roller 111, a lift sensor 112, a feed roller 113, a separation roller 114, a second medium sensor 115, a tilt sensor 116, first to fifth conveying rollers 117a-e, first to fifth driven rollers 118a-e, and an imaging device 119, etc.

[0023] The number of each of the pick roller 111, the feed roller 113, the separation roller 114, the first to fifth conveyor rollers 117a-e, and / or the first to fifth driven rollers 118a-e is not limited to one, and may be more than one. In this case, the multiple pick rollers 111, the feed roller 113, the separation roller 114, the first to fifth conveyor rollers 117a-e, and / or the first to fifth driven rollers 118a-e are arranged at intervals in the width direction A4.

[0024] The surface of first housing 101 facing second housing 102 forms first guide 101a of the medium transport path, and the surface of second housing 102 facing first housing 101 forms second guide 102a of the transport path.

[0025] The first medium sensor 110 is disposed on the mounting table 103, which is upstream of the feed roller 113 and the separation roller 114, and detects whether or not a medium is placed on the mounting table 103. The first medium sensor 110 detects 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 110 generates and outputs a first medium signal having a different signal value depending on whether or not a medium is placed on the mounting table 103. Note that the first medium sensor 110 may be any other sensor capable of detecting whether or not a medium is placed on the mounting table 103, such as a light detection sensor.

[0026] Pick roller 111 is disposed in second housing 102. Pick roller 111 comes into contact with a medium placed on placement table 103 that has been raised to approximately the same height as the medium transport path, and feeds the medium downstream.

[0027] Floating sensor 112 is disposed inside second housing 102 and downstream of pick roller 111. Floating sensor 112 detects floating of the medium fed by pick roller 111. Floating of the medium refers to the fed medium being bent toward second housing 102 with respect to the transport path. Floating sensor 112 detects floating of the medium by generating and outputting a floating signal having a different signal value depending on whether the medium is floating or not. The configuration of floating sensor 112 will be described later with reference to FIG. 3.

[0028] The feed roller 113 is disposed inside the second housing 102 and downstream of the pick roller 111. The feed roller 113 feeds the medium fed by the pick roller 111 further downstream. The separation roller 114 is disposed inside the first housing 101 so as to face the feed roller 113. The separation roller 114 is a so-called brake roller or retard roller, and can rotate in the opposite direction to the direction in which the medium is fed, or can be stopped. The feed roller 113 and the separation roller 114 separate the medium and feed it one by one. The feed roller 113 is disposed above the separation roller 114, and the medium conveying device 100 feeds the medium by a so-called top-down method. The feed roller 113 may be disposed below the separation roller 114, and the medium conveying device 100 may feed the medium by a so-called bottom-up method.

[0029] The second medium sensor 115 is disposed downstream of the feed roller 113 and the separation roller 114. The second medium sensor 115 detects the medium. The second medium sensor 115 is a regression type prism sensor, and includes a light emitting element such as an LED (Light Emitting Diode) and a light receiving element such as a photodiode disposed inside the first housing 101, and a light guiding member such as a prism disposed inside the second housing 102. The light guiding member faces the light emitting element and the light receiving element across the medium transport path, and is disposed so as to guide the light irradiated from the light emitting element to the light receiving element. The second medium sensor 115 generates and outputs a signal having a signal value according to the intensity of the light detected by the light receiving element, that is, a signal having a different signal value depending on whether the light irradiated from the light emitting element is blocked by the medium, as a second medium signal. For example, the second medium sensor 115 detects the medium when the second medium signal indicates that the light irradiated from the light emitting element is blocked by the medium. The second medium sensor 115 may be any other sensor capable of detecting the medium, such as a contact detection sensor.

[0030] The tilt sensor 116 is disposed downstream of the feed roller 113 and the separation roller 114. The tilt sensor 116 detects the tilt of the medium. The tilt sensor 116 has a first detection sensor 116-1 and a second detection sensor 116-2 that are disposed at an interval in the width direction A4 and detect the medium at the disposed position.

[0031] The first detection sensor 116-1 is a regression type prism sensor similar to the second medium sensor 115, and includes a light emitting element such as an LED and a light receiving element such as a photodiode arranged inside the first housing 101, and a light guiding member such as a prism arranged inside the second housing 102. The first detection sensor 116-1 generates and outputs a first detection signal having a signal value according to the intensity of light detected by the light receiving element, that is, a signal having a different signal value depending on whether or not the light irradiated from the light emitting element is blocked by the medium. For example, the first detection sensor 116-1 detects the leading edge of the medium when the first detection signal changes from a state indicating that the light irradiated from the light emitting element is not blocked by the medium to a state indicating that the light irradiated from the light emitting element is blocked by the medium.

[0032] The second detection sensor 116-2 is also a regression type prism sensor similar to the second medium sensor 115, and includes a light emitting element such as an LED and a light receiving element such as a photodiode arranged inside the first housing 101, and a light guiding member such as a prism arranged inside the second housing 102. The second detection sensor 116-2 generates and outputs a second detection signal having a signal value according to the intensity of light detected by the light receiving element, that is, a signal having a signal value that differs depending on whether or not the light irradiated from the light emitting element is blocked by the medium. For example, the second detection sensor 116-2 detects the leading edge of the medium when the second detection signal changes from a state indicating that the light irradiated from the light emitting element is not blocked by the medium to a state indicating that the light irradiated from the light emitting element is blocked by the medium.

[0033] The tilt sensor 116 detects that the medium is tilted when the time difference between the time when the first detection sensor 116-1 detects the leading edge of the medium and the time when the second detection sensor 116-2 detects the leading edge of the medium is equal to or greater than a threshold value.

[0034] The first to fifth conveying rollers 117a-e and the first to fifth driven rollers 118a-e are provided facing each other downstream of the feeding roller 113 and the separation roller 114. The first to fourth conveying rollers 117a-d and the first to fourth driven rollers 118a-d convey the medium fed by the feeding roller 113 and the separation roller 114 downstream. The fifth conveying roller 117e and the fifth driven roller 118e discharge the medium conveyed by the first to fourth conveying rollers 117a-d and the first to fourth driven rollers 118a-d onto the discharge tray 104.

[0035] The imaging device 119 is disposed downstream of the first transport roller 117a in the transport direction A2, and captures an image of the medium transported by the first transport roller 117a and the first driven roller 118a. The imaging device 119 has a first imaging device 119a and a second imaging device 119b disposed opposite each other across the transport path of the medium.

[0036] The first imaging device 119a 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 119a 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 119a captures an image of the surface of the medium being transported, generates an input image, and outputs it.

[0037] Similarly, the second imaging device 119b 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 119b 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 119b captures an image of the back side of the medium being transported, generates an input image, and outputs it.

[0038] The imaging device 119 may include only one of the first imaging device 119a and the second imaging device 119b and may read only one side of the medium. The first imaging device 119a and the second imaging device 119b may include a CIS line sensor of an equal-magnification optical system type having an imaging element based on a CCD (Charge Coupled Device) instead of a CIS line sensor of an equal-magnification optical system type having an imaging element based on a CMOS. The first imaging device 119a and the second imaging device 119b may include a line sensor of a reduction optical system type having an imaging element based on a CMOS or CCD.

[0039] The medium placed between the pair of side guides 103a of the placement table 103 is conveyed between the first guide 101a and the second guide 102a along the conveying direction A2 by the rotation of the pick roller 111 and the feed roller 113 in the direction in which the medium is fed. The user can set the feeding mode of the medium conveying device 100 to either a separation mode in which the medium is separated while being fed, or a non-separation mode in which the medium is fed without being separated. The feeding mode is set by the user operating the operation device 105 or an information processing device that is communicatively connected to the medium conveying device 100. When the feeding mode is set to the separation mode, the separation roller 114 rotates in the opposite direction to the feeding direction of the medium or stops. This restricts the feeding of media other than the separated medium, and prevents double feeding. On the other hand, when the feeding mode is set to the non-separation mode, the separation roller 114 rotates in the feeding direction of the medium.

[0040] The medium is transported between first guide 101a and second guide 102a by first transport roller 117a rotating in the direction in which the medium is fed, and is sent to the imaging position of imaging device 119, where it is imaged by imaging device 119. Furthermore, the medium is discharged onto discharge tray 104 by second to fifth transport rollers 117b to e each rotating in the direction in which the medium is fed.

[0041] 3 is a perspective view of the floating sensor 112. The floating sensor 112 has an arm 112a and a horseshoe-shaped sensor 112b.

[0042] The arm 112a is provided above the medium transport path so as to extend in the transport direction A2, and is disposed so that its lower surface faces the first guide 101a at a predetermined distance. A plurality of lift sensors 112 may be disposed at intervals in the width direction A4. In this case, each arm 112a is disposed so as to have the same height relative to the first guide 101a. The downstream end 112c of the arm 112a is rotatably engaged with the second housing 102 so that the upstream end 112d swings. As a result, when the medium is lifted, the medium comes into contact with the arm 112a, and the medium rotates the arm 112a to raise it. When the medium is not lifted, the distance between the lower surface of the arm 112a and the first guide 101a is appropriately set according to the magnitude of the bending of the medium that needs to be detected by the lift sensor 112.

[0043] The horseshoe-shaped sensor 112b has a light-emitting element 112e, a light-receiving element 112f, and a connection portion 112g that connects the light-emitting element 112e and the light-receiving element 112f. The light-emitting element 112e and the light-receiving element 112f are arranged to face each other. The light-emitting element 112e is an LED or the like, and emits light toward the light-receiving element 112f. The light-receiving element 112f is a photodiode or the like. The light-emitting element 112e and the light-receiving element 112f are examples of a light-emitting unit and a light-receiving unit, respectively. The light-receiving element 112f is provided facing the light-emitting element 112e across the arm 112a, and detects light from the light-emitting element 112e. The light-receiving element 112f generates and outputs a lift-up detection signal, which is an electrical signal according to the intensity of the detected light. The horseshoe-shaped sensor 112b is an example of a detector.

[0044] The arm 112a is disposed between the light emitting element 112e and the light receiving element 112f in the initial state, and is disposed at a position not facing the light emitting element 112e and the light receiving element 112f in the raised state. That is, the arm 112a is formed so as to block the light from the light emitting element 112e to the light receiving element 112f in the not raised state, and to allow the light from the light emitting element 112e to pass to the light receiving element 112f in the raised state. The horseshoe-shaped sensor 112b generates a signal having a signal value according to the intensity of the light detected by the light receiving element 112f as a lifting signal, that is, a signal having a different signal value depending on whether the medium being fed is lifted or not. For example, the lifting sensor 112 detects the lifting of the medium when the intensity of the light detected by the light receiving element 112f, which is indicated by the lifting signal, is equal to or greater than a threshold value.

[0045] 4 is a diagram showing the arrangement of the floating sensor 112, the second medium sensor 115, and the tilt sensor 116. FIG. 4 is a diagram showing the transport path as viewed from above.

[0046] The floating sensor 112 has a first floating sensor 112-1 and a second floating sensor 112-2. The first floating sensor 112-1 is disposed on the left side of the pick roller 111 and the feed roller 113 in the transport direction A2, i.e., in the width direction A4. The second floating sensor 112-2 is disposed on the right side of the pick roller 111 and the feed roller 113 in the transport direction A2, i.e., in the width direction A4. The configuration of the first floating sensor 112-1 and the configuration of the second floating sensor 112-2 are the same except that they are symmetrical with respect to the width direction A4.

[0047] The first lifting sensor 112-1 and the second lifting sensor 112-2 are disposed at a predetermined distance in the width direction A4 from the pick roller 111 and the feed roller 113. The predetermined distance is set so that when a medium (e.g., A5 size) having the smallest length in the width direction A4 among media that are generally likely to be bound with staples, clips, or the like is transported through the center in the width direction A4, the end of the medium in the width direction A4 passes under the arm 112a. This allows the lifting sensor 112 to reliably detect the lifting of a bound medium when bound media bound with staples, clips, or the like is transported.

[0048] An upstream end 112d of the arm 112a of the first lift sensor 112-1 and the second lift sensor 112-2 is located upstream of the upstream end of the nip width 111a of the pick roller 111. In addition, a downstream end 112c of the arm 112a of the first lift sensor 112-1 and the second lift sensor 112-2 is located downstream of the downstream end of the nip width 113a of the feed roller 113 and the separation roller 114. In this way, the lift sensor 112 detects lift of the medium between the upstream end of the nip width 111a of the pick roller 111 and the downstream end of the nip width 113a of the feed roller 113 and the separation roller 114.

[0049] The second medium sensor 115 is disposed downstream of the feed roller 113 and the separation roller 114. The second medium sensor 115 is disposed between the two feed rollers 113, for example, at the center in the width direction A4. Note that a plurality of second medium sensors 115 may be disposed side by side at intervals along the width direction A4.

[0050] The first detection sensor 116-1 and the second detection sensor 116-2 of the tilt sensor 116 are arranged side by side at an interval in the width direction A4 downstream of the second medium sensor 115. The first detection sensor 116-1 is arranged on the left side of the pick roller 111 and the feed roller 113 toward the transport direction A2, i.e., in the width direction A4. The second detection sensor 116-2 is arranged on the right side of the pick roller 111 and the feed roller 113 toward the transport direction A2, i.e., in the width direction A4. That is, the first detection sensor 116-1 is arranged on the same side of the pick roller 111 as the first lift sensor 112-1, and the second detection sensor 116-2 is arranged on the same side of the pick roller 111 as the second lift sensor 112-2.

[0051] 5 is a block diagram showing an example of a schematic configuration of the medium conveying device 100. The medium conveying device 100 further includes a motor 131, an interface device 132, a storage device 140, a processing circuit 150, and the like, in addition to the above-mentioned configuration.

[0052] The motor 131 includes one or more motors. The motor 131 rotates the pick roller 111, the feed roller 113, the separation roller 114, and the first to fifth transport rollers 117a-e in response to a control pulse from the processing circuit 150 to feed and transport the medium. Note that the first to fifth driven rollers 118a-e may be rotated by the motor 131, rather than being driven by the rotation of each transport roller.

[0053] The interface device 132 has an interface circuit conforming to a serial bus such as USB. The interface device 132 is electrically connected to an information processing device (not shown) (for example, a personal computer, a mobile information terminal, etc.) to transmit and receive an input image and various information. Instead of the interface device 132, the medium conveying device 100 may include a communication unit having an antenna for transmitting and receiving wireless signals and a communication interface circuit for transmitting and receiving signals through a wireless communication line. The communication protocol used by the communication interface circuit is, for example, a wireless LAN (Local Area Network).

[0054] The storage device 140 includes a memory device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. The storage device 140 also stores computer programs, databases, tables, and the like used for various processes of the medium conveying device 100. The computer programs may be installed in the storage device 140 from a computer-readable and non-transitory portable recording medium using a known setup program or the like. The portable recording medium is, for example, a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or the like.

[0055] The processing circuit 150 operates based on a program stored in advance in the storage device 140. The processing circuit 150 is, for example, a CPU (Central Processing Unit). The processing circuit 150 may be a DSP (Digital Signal Processor), an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or the like.

[0056] The processing circuit 150 is connected to the operation device 105, the display device 106, the first medium sensor 110, the lift sensor 112, the second medium sensor 115, the tilt sensor 116, the image capture device 119, the motor 131, the interface device 132, the storage device 140, etc., and controls each of these components. The processing circuit 150 controls the motor 131 to transport the medium, controls the image capture device 119 to obtain an input image, and transmits the obtained input image to the information processing device via the interface device 132. The processing circuit 150 also receives a lift detection signal received from the lift sensor 112, a second medium signal received from the second medium sensor 115, and the tilt sensor 116 from the image capture device 119. Based on the signal received from 6, it is determined whether the medium being conveyed is a binding medium.

[0057] FIG. 6 is a diagram showing a schematic configuration of the storage device 140 and the processing circuit 150. As shown in FIG.

[0058] The storage device 140 stores various programs such as a control program 141 and a determination program 142. Each of these programs is a functional module implemented by software that runs on a processor. The processing circuit 150 reads each of the programs stored in the storage device 140 and operates according to the read programs, thereby functioning as a control unit 151 and a determination unit 152.

[0059] 7 is a flow diagram showing the operation flow of the medium conveying process executed by the medium conveying device 100. The medium conveying process is realized by the processing circuit 150 cooperating with each element of the medium conveying device 100 based on a program stored in the storage device 140.

[0060] First, the control unit 151 waits until it receives an operation signal instructing to read a medium (S101). The operation signal is supplied from the operation device 105 to the control unit 151 in response to a user inputting an instruction to read a medium to the operation device 105. The operation signal may be supplied from the information processing device via the interface device 132 in response to a user inputting an instruction to read to the information processing device.

[0061] Next, control unit 151 determines whether or not a medium is placed on placement table 103 based on the first medium signal output from first medium sensor 110 (S102). If no medium is placed on placement table 103 (S102-No), the medium imaging process ends.

[0062] If a medium is placed on the table 103 (S102-Yes), the control unit 151 drives a motor for moving the table 103, and raises the table 103 to a position where the medium can be fed. The control unit 151 drives the motor 131 to rotate the pick roller 111, the feed roller 113, the separation roller 114, and the first to fifth transport rollers 117a-e, and feeds and transports the medium placed on the table 103 (S103).

[0063] Next, the control unit 151 determines whether or not a medium has been detected by the second medium sensor 115 based on the second medium signal output from the second medium sensor 115 (S104). When the second medium signal changes from a state indicating that the light irradiated from the light emitting element is not blocked by the medium to a state indicating that the light is blocked by the medium, the control unit 151 determines that the leading edge of the medium has reached the position of the second medium sensor 115 and the medium has been detected by the second medium sensor 115. When the medium has not been detected by the second medium sensor 115 (S104-No), the process returns to S104, and the control unit 151 waits until the medium is detected by the second medium sensor 115.

[0064] If the medium is detected by the second medium sensor 115 (S104-Yes), the determination unit 152 executes a determination process to determine whether the medium is a bound medium (S105). The details of the determination process will be described later.

[0065] Next, the control unit 151 obtains the result of the determination process from the determination unit 152 and determines whether the medium is a bound medium (S106). If the medium is a bound medium (S106-Yes), the control unit 151 stops the motor 131 to stop the transport of the medium (S107). The control unit 151 also causes the display device 106 to display a screen indicating that an abnormality has occurred in the transport of the medium. This ends the medium transport process. Note that stopping the transport of the medium and causing the display device 106 to display a screen indicating that an abnormality has occurred in the transport of the medium are examples of executing abnormality control.

[0066] If the medium is not a bound medium (S106-No), the control unit 151 captures an image of the medium (S108). The control unit 151 waits until the leading edge of the medium reaches an imaging start position between the second medium sensor 115 and the imaging device 119. For example, the control unit 151 determines that the leading edge of the medium has reached the imaging start position when the leading edge of the medium has been transported a predetermined distance since reaching the position of the second medium sensor 115. When the leading edge of the medium has reached the imaging start position, the control unit 151 controls the imaging device 119 to sequentially capture images of the medium as the medium is transported, thereby generating an input image. The control unit 151 transmits the generated input image to the information processing device via the interface device 132.

[0067] Next, the control unit 151 determines whether or not a medium is placed on the placement table 103 based on the first medium signal output from the first medium sensor 110 (S109). If a medium is placed on the placement table 103 (S109-Yes), the medium conveying process returns to S104, and the control unit 151 waits until the next medium is detected by the second medium sensor 115. If no medium is placed on the placement table 103 (S109-No), the control unit 151 stops the motor 131. This ends the medium conveying process.

[0068] 8 is a flow diagram showing the flow of the determination process executed in S105 of the medium conveying process by the medium conveying device 100. In the determination process, it is determined whether or not the medium is a bound medium.

[0069] First, the determination unit 152 starts counting the determination period (S201). The determination period is the period from when the medium reaches the second medium sensor 115 until the medium is transported a predetermined distance. In this case, the determination unit 152 starts counting the control pulses supplied to the motor 131 that drives the first to fifth transport rollers 117a-e. The determination period may be the period from when the medium reaches the second medium sensor 115 until a predetermined time has elapsed. In this case, the determination unit 152 starts measuring the elapsed time from the time when the medium reaches the second medium sensor 115. For example, the determination period is set to the period until the rear end of a medium of a standard size (e.g., A4 size) passes through the feed roller 113 and the separation roller 114.

[0070] Next, the determination unit 152 determines whether or not the lifting of the medium has been detected by the lifting sensor 112 based on the lifting signal output by the lifting sensor 112 (S202). The determination unit 152 determines that the lifting of the medium has been detected when the intensity of the light detected by the light receiving element 112f, as indicated by the lifting signal, is equal to or greater than a threshold value.

[0071] When the floating sensor 112 detects that the medium is floating (S202-Yes), the determination unit 152 determines that the medium is a bound medium (S203). This ends the determination process.

[0072] If the lift sensor 112 does not detect lifting of the medium (S202-No), the determination unit 152 determines whether or not the tilt detection sensor 116 has detected that the medium is tilted (S204). The determination unit 152 determines that the medium is tilted when the first detection sensor 116-1 side of the medium leads the second detection sensor 116-2 side, or when the second detection sensor 116-2 side of the medium leads the first detection sensor 116-1 side.

[0073] For example, when the leading edge of the medium is detected by the first detection sensor 116-1 and the leading edge of the medium is not detected by the second detection sensor 116-2 even after a predetermined time has elapsed since the time when the first detection sensor 116-1 detected the leading edge of the medium, the determination unit 152 determines that the first detection sensor 116-1 side of the medium is ahead of the second detection sensor 116-2 side. Also, when the leading edge of the medium is detected by the second detection sensor 116-2 and the leading edge of the medium is not detected by the second detection sensor 116-2 even after a predetermined time has elapsed since the time when the second detection sensor 116-2 detected the leading edge of the medium, the determination unit 152 determines that the second detection sensor 116-2 side of the medium is ahead of the first detection sensor 116-1 side.

[0074] If the leading edge of the medium is not detected by either the first detection sensor 116-1 or the second detection sensor 116-2, the determination unit 152 determines that the medium is not detected as being tilted. If the leading edge of the medium is detected by only one of the first detection sensor 116-1 or the second detection sensor 116-2 but a predetermined time has not elapsed since the medium was detected, the determination unit 152 also determines that the medium is not detected as being tilted. If the medium is detected by one of the first detection sensor 116-1 or the second detection sensor 116-2 before a predetermined time has elapsed since the time when the medium was detected by the other, the determination unit 152 also determines that the medium is not detected as being tilted.

[0075] The predetermined time is set based on the allowable tilt of the medium. As described below, the detection of the tilt of the medium is for detecting whether the rear end of the medium rides up on the side guide 103a, so the allowable tilt is set, for example, to a range in which the rear end of the medium does not contact the side guide 103a when the leading edge of the medium is positioned at the center of the width direction A4. The predetermined time is set to the time difference between the time when the first detection sensor 116-1 detects the leading edge of the medium and the time when the second detection sensor 116-2 detects the leading edge of the medium when a medium having the maximum allowable tilt is transported.

[0076] When the inclination of the medium is detected (S204-Yes), the determination unit 152 makes it difficult to determine that the medium is a binding medium based on the detection result of the floating of the medium by the floating sensor 112 on the leading side of the medium out of the first floating sensor 112-1 and the second floating sensor 112-2 (S205). That is, when the determination unit 152 detects that the first detection sensor 116-1 side of the medium is leading the second detection sensor 116-2 side, it makes it difficult to determine that the medium is a binding medium based on the detection result of the first floating sensor 112-1. Also, when the determination unit 152 detects that the second detection sensor 116-2 side of the medium is leading the first detection sensor 116-1 side, it makes it difficult to determine that the medium is a binding medium based on the detection result of the second floating sensor 112-2.

[0077] Making it difficult to determine that the medium is a binding medium based on the detection result of the lifting of the medium by the lifting sensor 112 on the leading side of the medium means, for example, not using the detection result of the lifting sensor 112 on the leading side to determine that the medium is a binding medium. For example, when the first detection sensor 116-1 side of the medium is leading, the determination unit 152 determines that the medium is a binding medium when the second lifting sensor 112-2 detects the lifting of the medium in S202, but does not determine that the medium is a binding medium when only the first lifting sensor 112-1 detects the lifting of the medium. Similarly, when the second detection sensor 116-2 side of the medium is leading, the determination unit 152 determines that the medium is a binding medium when the first lifting sensor 112-1 detects the lifting of the medium in S202, but does not determine that the medium is a binding medium when only the second lifting sensor 112-2 detects the lifting of the medium.

[0078] If the tilt of the medium is not detected (S204-No), the determination process proceeds to S206.

[0079] Next, the determination unit 152 determines whether or not the determination period has ended (S206). For example, the determination unit 152 determines whether or not the determination period has ended based on the number of control pulses supplied to the motor 131 after the medium is detected by the second medium sensor 115.

[0080] If the determination period has not ended (S206-No), the determination process proceeds to S202.

[0081] If the determination period has ended (S206-Yes), the determination process ends.

[0082] The principle of the determination process will be described below.

[0083] FIG. 9A is a schematic side view of the bound medium that has reached the position of the feed roller 113 and the separation roller 114. In the example shown in FIG. 9A, the bound medium is a lower medium M1 and an upper medium M2 bound by the binding portion S. When the bound medium reaches the position of the feed roller 113 and the separation roller 114, the lower medium M1 is stopped by the rotation of the separation roller 114, and only the upper medium M2 attempts to advance in the conveying direction A2 by the rotation of the feed roller 113. At this time, since the leading end of the upper medium M2 is fixed to the lower medium M1 by the binding portion S, lifting occurs between the region T of the upper medium M2 that contacts the feed roller 113 and the binding portion S. Therefore, it is possible to determine whether the medium is a bound medium based on whether the lifting sensor 112 detects the lifting of the medium.

[0084] 9(B) is a schematic plan view of the bound medium that has reached the positions of the feed roller 113 and the separation roller 114. As shown in FIG. 9(B), the upper medium M2 tries to proceed in the conveying direction A2 due to the rotation of the feed roller 113, but since one side of the leading edge is bound by the binding portion S, the upper medium M2 is tilted so that the side opposite the binding portion S leads in the conveying direction A2. In other words, when the bound medium is being conveyed, one side of the leading edge of the medium leads in the conveying direction A2, and the other side is lifted up.

[0085] Fig. 10(A) is a schematic diagram showing a plan view of a normal medium (meaning a medium that is not a bound medium) transported at an angle with respect to the transport direction A2, and Fig. 10(B) is a schematic diagram showing a normal medium transported at an angle as viewed in the transport direction A2. If the medium is significantly tilted, the rear end of the medium may ride up on side guide 103a of loading platform 103 as the medium is fed. In this case, lifting occurs between portion V of the medium that rides up on side guide 103a and area T with which pick roller 111 comes into contact. Therefore, even when a normal medium is transported at an angle, lifting of the medium is detected by lifting sensor 112.

[0086] When the trailing end of the medium rides up on side guide 103a, the medium is tilted, and the side that rides up on side guide 103a leads the other side in the width direction A4. In the example shown in Figures 10(A) and (B), the right side of the medium in the transport direction A2 leads the left side, so the right side of the trailing end rides up on side guide 103a. Therefore, the medium also lifts up on the right side with respect to pick roller 111. In other words, when the medium is normally transported at an angle, one side of the leading end of the medium in the transport direction A2 leads, and lifting occurs on that one side.

[0087] Therefore, by making it difficult for the determination unit 152 to determine that the medium is a binding medium based on the detection result of the medium floating by the floating sensor 112 on the leading side of the medium, it is possible to prevent the medium that is transported at an angle from being mistakenly detected as a binding medium.

[0088] As described above, when one side of the medium is ahead of the other side in the conveying direction A2, the medium conveying device 100 makes it difficult to determine that the medium is a bound medium based on the detection result of the lifting of the medium by the lifting sensor 112 on one side. This enables the medium conveying device 100 to distinguish between a bound medium and a normal medium conveyed at an angle, and to more accurately determine whether or not the medium is one for which abnormality control should be executed.

[0089] In the above description, in S205 of the determination process, the determination unit 152 does not use the detection result of the floating sensor 112 on the leading side of the medium to determine whether the medium is bound, but this is not limited to the example. The determination unit 152 may shorten the determination period for the floating sensor 112 on the leading side.

[0090] In this case, in S201 of the determination process, the determination unit 152 starts measuring the determination period for each of the first lifting sensor 112-1 and the second lifting sensor 112-2. In S205, the determination unit 152 shortens the determination period for the leading lifting sensor 112 by a predetermined time. In addition, in S206, the determination unit 152 determines whether or not the determination period has ended for each of the first lifting sensor 112-1 and the second lifting sensor 112-2. If the determination period for only one of the first lifting sensor 112-1 and the second lifting sensor 112-2 has ended, the determination unit 152 does not use the detection result of the lifting sensor 112 whose determination period has ended for determining the binding medium, and the determination process returns to S202. If the determination periods for both the first lifting sensor 112-1 and the second lifting sensor 112-2 have ended, the determination process ends. By appropriately setting the judgment period after the change, the media conveying device 100 can distinguish between bound media and media conveyed at an angle with high accuracy, and can more accurately determine whether or not the media is one for which abnormal control should be performed.

[0091] In the above description, the lift sensor 112 has the arm 112a and the horseshoe-shaped sensor 112b, but is not limited to this example. The lift sensor 112 may be an optical distance measuring sensor including a light-emitting element such as an LED arranged above the medium transport path, and a light-receiving element such as a photodiode that detects light emitted from the LED and reflected by the medium. In this case, the lift sensor 112 outputs a signal as a lift signal indicating a different value depending on the time from when the light-emitting element emits light to when the light-receiving element receives the light. For example, the lift sensor 112 detects the lift of the medium when the time indicated by the lift signal from when the light-emitting element emits light to when the photodiode receives the light is equal to or less than a threshold value.

[0092] In this case, in S205 of the determination process, the determination unit 152 may further reduce the threshold value of the lift sensor 112 on the leading side of the medium, so that it is difficult to determine that the medium is a bound medium based on the detection result of the lift of the medium by the lift sensor 112 on the leading side of the medium. For example, when the first detection sensor 116-1 side of the medium is leading, the determination unit 152 reduces the threshold value of the first lift sensor 112-1. Also, when the second detection sensor 116-2 side of the medium is leading, the determination unit 152 reduces the threshold value of the second lift sensor 112-2. By appropriately setting the changed threshold value, the medium conveying device 100 can accurately distinguish between a bound medium and a tilted medium, and can more accurately determine whether the medium is a medium for which abnormality control should be performed.

[0093] 11 is a diagram showing a transport path of a medium transport device 200 according to another embodiment. The medium transport device 200 differs from the medium transport device 100 in that it has a tilt sensor 216 instead of the tilt sensor 116.

[0094] The tilt sensor 216 is disposed upstream of the pick roller 111. The tilt sensor 216 detects the tilt of the medium. The tilt sensor 216 has a first speed sensor 216-1 and a second speed sensor 216-2 that are disposed at an interval in the width direction A4 and detect the speed of the medium.

[0095] The first speed sensor 216-1 is, for example, a slit-type encoder. The first speed sensor 216-1 includes a rotating member having a slit and rotating as the medium passes, a light-emitting element such as an LED, and a light-receiving element such as a photodiode. Light pulses are generated when light emitted from the light-emitting element such as an LED passes through the rotating slit. The first speed sensor 216-1 generates and outputs a signal corresponding to the width or interval of the light pulse detected by the light-receiving element, that is, a signal corresponding to the moving speed of the medium, as a first speed signal.

[0096] The second velocity sensor 216-2 has a configuration similar to that of the first velocity sensor 216-1. The second velocity sensor 216-2 generates and outputs a signal corresponding to the width or interval of the light pulse detected by the light receiving element, that is, a signal corresponding to the moving speed of the medium, as a second velocity signal.

[0097] The tilt sensor 216 detects that the medium is tilted when the difference between the moving speed of the medium indicated by the first speed signal and the moving speed of the medium indicated by the second speed signal is equal to or greater than a threshold value.

[0098] The first speed sensor 216-1 and the second speed sensor 216-2 may be magnetic encoders that detect a change in magnetism caused by the rotation of a rotating member having a magnet.

[0099] 12 is a diagram showing a schematic arrangement of the floating sensor 112, the second medium sensor 115, and the tilt sensor 216. FIG. 12 is a diagram showing the transport path as viewed from above.

[0100] An upstream end 112d of the arm 112a of the first lift sensor 112-1 and the second lift sensor 112-2 is located upstream of the upstream end of the nip width 111a of the pick roller 111. Further, a downstream end 112c of the arm 112a of the first lift sensor 112-1 and the second lift sensor 112-2 is located downstream of the upstream end of the nip width of the first conveyor roller 117a. In this way, the lift sensor 112 detects lift of the medium between the upstream end of the nip width 111a of the pick roller 111 and the upstream end of the nip width of the first conveyor roller 117a.

[0101] The first speed sensor 216-1 and the second speed sensor 216-2 of the tilt sensor 216 are arranged side by side with an interval in the width direction A4 on the upstream side of the pick roller 111. The first speed sensor 216-1 is arranged on the left side of the pick roller 111 and the feed roller 113 toward the conveying direction A2, i.e., in the width direction A4. The second speed sensor 216-2 is arranged on the right side of the pick roller 111 and the feed roller 113 toward the conveying direction A2, i.e., in the width direction A4. In other words, the first speed sensor 216-1 is arranged on the same side of the pick roller 111 as the first lifting sensor 112-1, and the second speed sensor 216-2 is arranged on the same side of the pick roller 111 as the second lifting sensor 112-2.

[0102] Fig. 13 is a flow diagram showing the operational flow of the medium conveying process executed by medium conveying device 200. The medium conveying process is realized by processing circuit 150 working in cooperation with each element of medium conveying device 200 based on a program stored in storage device 140. The processes of S301 to S303 and S307 to S311 in Fig. 13 are similar to the processes of S101 to S103 and S105 to S109 in Fig. 7, so their explanation will be omitted and only S304 to S306 will be explained below.

[0103] After the motor 131 is driven in S303, the determination unit 152 determines whether or not the tilt detection sensor 216 has detected that the medium is tilted (S304). The determination unit 152 determines that the tilt of the medium has been detected when the first speed sensor 216-1 side of the medium is ahead of the second speed sensor 216-2 side, or when the second speed sensor 216-2 side of the medium is ahead of the first speed sensor 216-1 side. For example, the determination unit 152 determines that the tilt of the medium has been detected by the tilt detection sensor 216 when the difference between the moving speed of the medium indicated by the first speed signal and the moving speed of the medium indicated by the second speed signal is equal to or greater than a threshold value.

[0104] If it is detected that the medium is tilted (S304-Yes), the judgment unit 152 makes it difficult to determine that the medium is a bound medium based on the detection result of the medium floating by the floating sensor 112, which is the leading side of the medium, of the first floating sensor 116-1 and the second floating sensor 116-2 (S305).

[0105] If it is not detected that the medium is skewed (S304-No), the medium transport process proceeds to S306.

[0106] Next, control unit 151 determines whether or not the medium has been detected by second medium sensor 115 based on the second medium signal output from second medium sensor 115 (S306). If the medium has not been detected by second medium sensor 115 (S306-No), control unit 151 returns to S304 and waits until the tilt sensor 216 detects the tilt of the medium or until the medium is detected by second medium sensor 115.

[0107] In the determination process executed by the medium conveying device 200, the processes of S204 and S205 are omitted.

[0108] In this way, the medium conveying device 200 detects the inclination of the medium by the inclination sensor 216 arranged upstream of the pick roller. This allows the medium conveying device 200 to stop conveyance at that point in time when the lifting sensor 112 detects the lifting of the medium before the second medium sensor 115 detects the medium, making it possible to prevent damage to the bound medium.

[0109] 14 is a diagram showing a schematic configuration of a processing circuit 350 included in a medium conveying device according to another embodiment. The processing circuit 350 is used in place of the processing circuit 150, and executes a medium conveying process. The processing circuit 350 includes a control circuit 351 and a determination circuit 352. Each of these components may be formed of an independent integrated circuit, microprocessor, firmware, or the like.

[0110] The control circuit 351 is an example of a control unit, and has the same functions as the control unit 151. The control circuit 351 receives an operation signal from the operation device 105, a first medium signal from the first medium sensor 110, and a determination result in the determination process from the determination circuit 352, and controls the motor 131 based on the received signals and the determination result. The control circuit 351 also receives an input image from the imaging device 119, and transmits it to the information processing device via the interface device 132.

[0111] The determination circuit 352 is an example of a determination unit, and has the same function as the determination unit 152. The determination circuit 352 receives a lift detection signal, a second medium signal, and first and second detection signals, etc., from the lift sensor 112, the second medium sensor 115, and the tilt sensor 116, respectively. The determination circuit 352 determines whether the medium is a binding medium or not, etc., based on each received signal, and outputs the determination result to the control circuit 351.

[0112] As described above, the medium conveying device is capable of appropriately detecting the bound medium even when the processing circuit 350 is used.

[0113] It should be understood by those skilled in the art that various changes, substitutions, and modifications can be made to the present invention without departing from the spirit and scope of the present invention. For example, the above-mentioned embodiments and modifications may be appropriately combined within the scope of the present invention. [Explanation of symbols]

[0114] 100 Media transport device 111 Pick roller 112 Floating sensor 113 Feeding roller 114 Separation roller 115 Second Media Sensor 116 Tilt Sensor 151 Control section 152 Judgment section

Claims

1. A pick roller for feeding a medium, A first lift sensor disposed on one side with respect to the pick roller in the conveyance direction of the medium, downstream of the upstream end of the nip width of the pick roller, for detecting the lifting of the medium, A second lift sensor disposed on the other side with respect to the pick roller in the conveyance direction, downstream of the upstream end of the nip width of the pick roller, for detecting the lifting of the medium, A first detection sensor disposed on the same side as the first lift sensor with respect to the pick roller, for detecting the medium, A second detection sensor disposed on the same side as the second lift sensor with respect to the pick roller, for detecting the medium, A determination unit that determines that the medium is a predetermined medium when the height of the lifting of the medium detected by the first or second lift sensor is equal to or greater than a threshold value, A control unit that executes abnormal control when the medium is determined to be the predetermined medium, and has, The determination unit increases the threshold value for the first lift sensor when it is detected by the first and second detection sensors that the side of the first detection sensor of the medium precedes the side of the second detection sensor, A medium conveyance device characterized by the above.

2. Further comprising a separation roller disposed downstream of the pick roller in the conveyance direction, The first and second detection sensors are medium sensors that are disposed at intervals in a direction orthogonal to the conveyance direction, downstream of the downstream end of the nip width of the separation roller, and detect the medium at the disposed positions, The medium conveyance device according to claim 1.

3. Further comprising a separation roller disposed downstream of the pick roller in the conveyance direction, The first and second detection sensors are speed sensors that are disposed at intervals in a direction orthogonal to the conveyance direction, upstream of the upstream end of the nip width of the separation roller, and measure the speed of the medium, The medium conveyance device according to claim 1.

4. Further comprising a separation roller disposed downstream of the pick roller in the conveyance direction, The determination unit, When the lifting of the medium is detected by the first or second lift sensor within a predetermined determination period immediately after the medium has passed through the separation roller, determines that the medium is the predetermined medium, When it is detected that the side of the first detection sensor of the medium precedes the side of the second detection sensor, the determination period for the first lifting sensor is shortened. The medium conveyance device according to claim 1.

5. Feeding a medium by a pick roller, Detecting the lifting of the medium by a first lifting sensor disposed on one side with respect to the pick roller in the conveyance direction of the medium, downstream of the upstream end of the nip width of the pick roller; Detecting the lifting of the medium by a second lifting sensor disposed on the other side with respect to the pick roller in the conveyance direction, downstream of the upstream end of the nip width of the pick roller; Detecting the medium by a first detection sensor disposed on the same side as the first lifting sensor with respect to the pick roller; Detecting the medium by a second detection sensor disposed on the same side as the second lifting sensor with respect to the pick roller; When the height of the lifting of the medium detected by the first or second lifting sensor is equal to or greater than a threshold value, determining that the medium is a predetermined medium; When it is determined that the medium is the predetermined medium, executing abnormal control, including: In the determination, when it is detected by the first and second detection sensors that the side of the first detection sensor of the medium precedes the side of the second detection sensor, increasing the threshold value for the first lifting sensor; A medium conveyance method characterized by the above.

6. A control program for a medium conveyance device, comprising: a pick roller that feeds a medium; a first lifting sensor that is disposed on one side with respect to the pick roller in the conveyance direction of the medium, downstream of the upstream end of the nip width of the pick roller, and detects the lifting of the medium; a second lifting sensor that is disposed on the other side with respect to the pick roller in the conveyance direction, downstream of the upstream end of the nip width of the pick roller, and detects the lifting of the medium; a first detection sensor that is disposed on the same side as the first lifting sensor with respect to the pick roller and detects the medium; and a second detection sensor that is disposed on the same side as the second lifting sensor with respect to the pick roller and detects the medium, When the height of the lifting of the medium detected by the first or second lifting sensor is equal to or greater than a threshold value, determining that the medium is a predetermined medium; When it is determined that the medium is the predetermined medium, cause the medium conveyance device to execute abnormal control. In the determination, when it is detected by the first and second detection sensors that the side of the first detection sensor of the medium is ahead of the side of the second detection sensor, increase the threshold value for the first lifting sensor. A control program characterized by the above.

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