JP7601669B2 - MEDIUM CONVEYING DEVICE, CONTROL METHOD, AND CONTROL PROGRAM - Google Patents

Description

The present invention relates to a medium conveying device, a control method, and a control program.

In general, a media transport device such as a scanner that transports and captures media sequentially separates and feeds multiple media stacked on a loading platform. However, if multiple media are bound with staples or the like, there is a risk that the media may be damaged when separating them. Therefore, there is a demand for a media transport device that can properly detect such bound media.

In order to prevent damage to documents caused by the transport of bound media, a media transport device is known that uses an ultrasonic sensor to detect overlaps in fed media and stops transport when overlaps are detected (see, for example, Patent Document 1).

JP 2020-132373 A

There was a need for a media transport device that could more appropriately detect bound media and stop transport.

The purpose of the media transport device, control method, and control program is to properly detect the binding media.

The medium conveying device according to the embodiment includes a separation roller for separating the medium, a plurality of medium detection sensors arranged downstream in the medium conveying direction from the separation roller along a direction perpendicular to the conveying direction, a plurality of overlap detection sensors arranged downstream in the conveying direction from each of the medium detection sensors for detecting overlapping of the medium, a determination unit that determines whether the medium is a bound medium based on the detection results of the plurality of medium detection sensors and the plurality of overlap detection sensors, and a control unit that executes abnormality processing when it is determined that the medium is a bound medium, and the determination unit determines that the medium is a bound medium when, after the first medium detection sensor among the plurality of medium detection sensors detects the medium, an overlap detection sensor downstream of the media detection sensor does not detect an overlapping of the medium and an overlap detection sensor other than the overlap detection sensor detects an overlapping of the medium.

The control method according to the embodiment is a control method for a media conveying device having a separation roller for separating media, a plurality of media detection sensors arranged downstream in the media conveying direction from the separation roller along a direction perpendicular to the conveying direction, and a plurality of overlap detection sensors arranged downstream in the conveying direction from each media detection sensor for detecting overlapping of media, and includes determining whether the medium is a bound medium based on the detection results of the plurality of media detection sensors and the plurality of overlap detection sensors, and executing abnormality processing if the medium is determined to be a bound medium, and in the determination, if the first media detection sensor among the plurality of media detection sensors detects the medium, the overlap detection sensor downstream of the media detection sensor does not detect overlapping of media, and an overlap detection sensor different from the overlap detection sensor detects overlapping of media, the medium is determined to be a bound medium.

The control program according to the embodiment is a control program for a media transport device having a separation roller for separating media, multiple media detection sensors arranged downstream of the separation roller in the media transport direction along a direction perpendicular to the transport direction, and multiple overlap detection sensors arranged downstream of each media detection sensor in the transport direction for detecting overlapping of media. The control program causes the media transport device to determine whether the medium is a bound medium based on the detection results of the multiple media detection sensors and the multiple overlap detection sensors, and to execute abnormality processing if the medium is determined to be a bound medium. In the determination, if the first media detection sensor among the multiple media detection sensors detects the medium, the overlap detection sensor downstream of the media detection sensor does not detect overlapping of media, and an overlap detection sensor other than the overlap detection sensor detects overlapping of media, the control program determines that the medium is a bound medium.

According to the embodiment, the media conveying device, the control method, and the control program enable proper detection of the binding media.

The objects and advantages of the invention will be realized and obtained by means of the elements and combinations particularly pointed out in the claims. Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

1 is a perspective view of a medium conveying device 100 according to an embodiment. 2 is a diagram for explaining a medium transport path in the medium transport device 100. FIG. 11 is a diagram for explaining an example of the arrangement of a second medium sensor 115 and the like. FIG. 1 is a block diagram showing a schematic configuration of a medium conveying device 100. FIG. FIG. 2 is a diagram showing a schematic configuration of a storage device 140 and a processing circuit 150. FIG. 11 is a flow diagram showing an example of the flow of a medium reading process. FIG. 11 is a flow diagram showing an example of the flow of a determination process. FIG. 11 is a flow diagram showing an example of the flow of a determination process. FIG. 11 is a flow diagram showing an example of the flow of a determination process. 13A and 13B are diagrams for explaining a determination result when a binding medium is conveyed. 13A and 13B are diagrams for explaining a determination result when a binding medium is conveyed. 13A and 13B are diagrams for explaining a determination result when multiple feeding occurs. 13A and 13B are diagrams for explaining a determination result when a card medium is transported. 13 is a diagram for explaining another example of the arrangement of the second medium sensor 215 and the like. FIG. 13A and 13B are diagrams for explaining a determination result when a binding medium is conveyed. 13A and 13B are diagrams for explaining a determination result when a card medium is transported. FIG. 2 is a diagram showing an example of a schematic configuration of a processing circuit 350.

Below, a medium conveying device, a control method, and a control program according to one aspect of the present invention will be described with reference to the drawings. However, please note 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.

FIG. 1 is a perspective view showing a medium transport device 100 configured as an image scanner. The medium transport device 100 transports a medium, which is an original document, and captures an image of the medium. The medium is paper or cardboard, etc. The medium also includes bound media in which multiple media are bound together with staples, string, clips, etc., and card media that are smaller and thicker than paper, such as driver's licenses and IC cards. The medium transport device 100 may be a facsimile, a copier, a multifunction printer (MFP, Multifunction Peripheral), etc. The medium transport device 100 may also be a printer, etc., in which case the transported medium is a printed object, etc.

The medium transport device 100 includes a first housing 101, a second housing 102, a loading platform 103, a discharge platform 104, an operation device 105, and a display device 106.

The first housing 101 is disposed on the upper side of the media transport device 100 and engages with the second housing 102 by a hinge so that it can be opened and closed when the media is jammed or when cleaning the inside of the media transport device 100, etc.

The loading platform 103 engages with the second housing 102 so that the transported media can be placed thereon. The loading platform 103 is provided on the side of the second housing 102 on the media supply side so that it can move in a substantially vertical direction (height direction) A1 by a motor (not shown). The loading platform 103 is positioned at the bottom end so that media can be easily loaded when media is not being transported, and when media is being transported, it rises to a position where the uppermost medium loaded comes into contact with a pick roller (described later). The ejection platform 104 is formed on the first housing 101 so that it can hold the ejected media, and loads the ejected media.

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

In FIG. 1, arrow A2 indicates the media transport direction, arrow A3 indicates the media discharge direction, and arrow A4 indicates the width direction perpendicular to the media transport direction. In the following, upstream refers to the upstream side of the media transport direction A2 or the media discharge direction A3, and downstream refers to the downstream side of the media transport direction A2 or the media discharge direction A3.

Figure 2 is a diagram for explaining the transport path inside the media transport device 100. The transport path inside the media transport device 100 includes a first media sensor 111, a pick roller 112, a feed roller 113, a brake roller 114, multiple second media sensors 115A-C, multiple ultrasonic sensors 116A-C, first to eighth transport rollers 117a-h, first to eighth driven rollers 118a-h, a first imaging device 119a, and a second imaging device 119b. Below, each of the second media sensors 115A-C may be referred to as a second media sensor 115. Also, each of the ultrasonic sensors 116A-C may be referred to as an ultrasonic sensor 116. Also, the first imaging device 119a and the second imaging device 119b may be collectively referred to as an imaging device 119.

The number of each of the pick roller 112, the feed roller 113, the brake roller 114, the first to eighth conveyor rollers 117a-h, and/or the first to eighth driven rollers 118a-h is not limited to one, and may be more than one. In this case, the multiple pick rollers 112, the feed roller 113, the brake roller 114, the first to eighth conveyor rollers 117a-h, and/or the first to eighth driven rollers 118a-h are arranged at intervals in the width direction A4.

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

The first media sensor 111 is disposed on the mounting table 103, i.e., upstream of the feed roller 113 and the brake roller 114, and detects the state of the medium on the mounting table 103. The first media 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 media sensor 111 generates and outputs a first media signal whose signal value changes depending on whether or not the medium is placed on the mounting table 103. Note that the first media 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 media sensor 111.

The pick roller 112 is provided in the first housing 101, and contacts the medium placed on the mounting table 103, which is elevated to approximately the same height as the media transport path, and feeds the medium downstream.

The feed roller 113 is provided in the first housing 101 downstream of the pick roller 112, and feeds the media fed by the pick roller 112 further downstream. The brake roller 114 is provided in the second housing 102 facing the feed roller 113. The feed roller 113 and the brake roller 114 are examples of separation rollers, and perform a media separation operation, separate the media, and feed them one by one. The feed roller 113 is provided above the brake roller 114, and the media transport device 100 feeds the media using a so-called top-loading method.

The second media sensor 115 is disposed downstream of the feed roller 113 and the brake roller 114 and upstream of the ultrasonic sensor 116. The second media sensor 115 is an example of a media detection sensor, and detects whether or not a medium is present at that position. The second media sensor 115 is a regression prism sensor, and includes a light-emitting element, a light-receiving element, and a light-guiding member.

The light emitting element and the light receiving element are arranged outside the medium transport path, sandwiching the second guide 102a. The light guide member is a light guide tube such as a U-shaped prism, and is arranged outside the medium transport path, sandwiching the first guide 101a, with both ends facing the light emitting element and the light receiving element, respectively. The light emitting element is an LED (Light Emitting Diode) or the like, and irradiates light toward the light guide member across the medium transport path. The light receiving element receives light irradiated from the light emitting element and guided by the light guide member. The light receiving element generates and outputs a second medium signal, which is an electrical signal corresponding to the intensity of the received light. When a medium is present at the position of the second medium sensor 115, the light irradiated from the light emitting element is blocked by the medium, so that the signal value of the second medium signal changes depending on whether a medium is present or not at the position of the second medium sensor 115.

The configuration of the second media sensor 115 is not limited to the above example. For example, a reflective member such as a mirror may be used instead of the light-guiding member. The second media sensor 115 may also be composed of only a light-emitting element and a light-receiving element. In this case, the light-emitting element and the light-receiving element are respectively arranged in the first housing 101 and the second housing 102 so as to face each other across the media transport path. The second media sensor 115 may also be a contact detection sensor similar to the first media sensor 111.

The ultrasonic sensor 116 is disposed downstream of the feed roller 113 and the brake roller 114 and upstream of the first to eighth conveyor rollers 117a-h and the first to eighth driven rollers 118a-h. The ultrasonic sensor 116 has an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic transmitter and the ultrasonic receiver are disposed near the medium conveying path, facing each other across the conveying path. The ultrasonic transmitter is disposed outside the medium conveying path across the first guide 101a, and the ultrasonic receiver is disposed outside the medium conveying path across the second guide 102a. The ultrasonic transmitter emits ultrasonic waves. The ultrasonic receiver receives ultrasonic waves emitted by the ultrasonic transmitter that have passed through the medium, and generates and outputs an ultrasonic signal, which is an electrical signal corresponding to the magnitude of the received ultrasonic waves.

The ultrasonic waves emitted by the ultrasonic transmitter are attenuated when passing through a medium. In particular, when ultrasonic waves pass through multiple media, they are significantly attenuated by the air layers in the multiple media, so that overlapping of media is detected based on the magnitude of the ultrasonic waves received by the ultrasonic receiver. The ultrasonic sensor 116 is an example of an overlap detection sensor for detecting overlapping of media.

The first to eighth transport rollers 117a-h and the first to eighth driven rollers 118a-h are provided downstream of the feed roller 113 and the brake roller 114, and transport the medium fed by the feed roller 113 and the brake roller 114 downstream. The first to eighth transport rollers 117a-h and the first to eighth driven rollers 118a-h are arranged opposite each other with the medium transport path in between.

The first imaging device 119a is provided downstream of the first and second transport rollers 117a-b and the first and second driven rollers 118a-b in the medium transport direction A2, i.e., downstream of the ultrasonic sensor 116. The first imaging device 119a has a line sensor using a CIS (Contact Image Sensor) of a 1:1 optical system type having imaging elements using CMOS (Complementary Metal Oxide Semiconductor) arranged in a line in the main scanning direction. The first imaging device 119a has a lens that forms an image on the imaging element, and an A/D converter that amplifies the electrical signal output from the imaging element and performs analog-to-digital (A/D) conversion. The first imaging device 119a captures the surface of the medium being transported to generate an input image and output it.

The second imaging device 119b is provided downstream of the first and second transport rollers 117a-b and the first and second driven rollers 118a-b in the medium transport direction A2, i.e., downstream of the ultrasonic sensor 116. The second imaging device 119b has a line sensor using a CIS (Contact Image Sensor) of a 1:1 optical system type having imaging elements using CMOS (Complementary Metal Oxide Semiconductor) arranged in a line in the main scanning direction. The second imaging device 119b has a lens that forms an image on the imaging element, and an A/D converter that amplifies the electrical signal output from the imaging element and performs analog-to-digital (A/D) conversion. The second imaging device 119b images the back side of the medium being transported to generate an input image and output it.

The medium conveying device 100 may be configured with only one of the first imaging device 119a and the second imaging device 119b, and may 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.

The medium placed on the mounting table 103 is transported between the first guide 101a and the second guide 102a in the media transport direction A2 by the rotation of the pick roller 112 and the feed roller 113 in the media feed directions A5 and A6, respectively. On the other hand, when multiple media are placed on the mounting table 103, only the media placed on the mounting table 103 that is in contact with the feed roller 113 is separated by the rotation of the brake roller 114 in the opposite direction A7 to the media feed direction. A torque limiter is provided on the brake roller 114. As a result, when only one medium is placed on the mounting table 103, the brake roller 114 does not prevent the medium from being transported in the media transport direction A2.

The medium is guided by the first guide 101a and the second guide 102a and sent to the imaging position of the imaging device 119 by the rotation of the first and second transport rollers 117a-b in the directions of the arrows A8-A9, and is imaged by the imaging device 119. The medium is then discharged onto the discharge tray 104 by the rotation of the third to eighth transport rollers 117c-h in the directions of the arrows A10-A15, respectively. The discharge tray 104 holds the medium discharged by the eighth transport roller 117h.

Figure 3 is a diagram for explaining an example of the arrangement of the second medium sensor 115 and the ultrasonic sensor 116. Figure 3 is a schematic diagram of the second housing 102 viewed from above with the first housing 101 open.

In the example shown in FIG. 3, three second media sensors 115A-C are arranged downstream of the brake roller 114 in the media transport direction A2, spaced apart along the width direction A4 perpendicular to the transport direction. All three second media sensors 115A-C are arranged at approximately the same position in the media transport direction A2.

In the example shown in FIG. 3, three ultrasonic sensors 116A-C are arranged downstream of the second media sensors 115A-C in the media transport direction A2. Each ultrasonic sensor 116A-C is arranged so that at least a portion of it overlaps with each second media sensor 115A-C in the width direction A4, that is, so that at least a portion of it overlaps with each second media sensor 115A-C when viewed from the media transport direction A2. All three ultrasonic sensors 116A-C are arranged at approximately the same position in the media transport direction A2.

The number of second medium sensors 115 and ultrasonic sensors 116 is not limited to three, but may be any number equal to or greater than two.

Figure 4 is a diagram showing an example of the schematic configuration of the medium conveying device 100. In addition to the above-mentioned configuration, the medium conveying device 100 further includes a motor 131, an interface device 132, a storage device 140, and a processing circuit 150.

The motor 131 includes one or more motors, and rotates the pick roller 112, the feed roller 113, the brake roller 114, and the first to eighth transport rollers 117a-h in response to a control signal from the processing circuit 150 to feed and transport the medium. Note that the first to eighth driven rollers 118a-h may be arranged to rotate by the driving force from the motor, rather than being driven to rotate in accordance with the rotation of each transport roller.

The interface device 132 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (not shown) (e.g., a personal computer, a portable information terminal, etc.) to transmit and receive scanned images and various information. Also, instead of the interface device 132, 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 according to a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network).

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. Computer programs may be installed into the storage device 140 from a computer-readable, non-transient portable recording medium using a known setup program or the like. Portable recording media include, for example, a CD-ROM (compact disc read only memory), a DVD-ROM (digital versatile disc read only memory), etc.

The processing circuit 150 is a circuit that operates based on a program that is pre-stored 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.

The processing circuit 150 is connected to the operation device 105, the display device 106, the first medium sensor 111, the second medium sensor 115, the ultrasonic sensor 116, the imaging 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 imaging 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 determines whether the medium being transported is a bound medium based on the second medium signal received from the second medium sensor 115 and the ultrasonic signal received from the ultrasonic sensor 116.

Figure 5 shows the schematic configuration of the memory device 140 and the processing circuit 150.

The storage device 140 stores various programs such as a control program 141 and a judgment program 142. Each of these programs is a functional module implemented by software running on a processor. The processing circuit 150 reads each program stored in the storage device 140 and operates according to the read programs, thereby functioning as a control unit 151 and a judgment unit 152. Note that the control unit 151 and the judgment unit 152 may each be configured as an integrated circuit, a microprocessor, firmware, etc. that is independent of the processing circuit 150.

Figure 6 is a flow diagram showing an example of the operation of a media reading process executed by the media conveying device 100. The media reading process is realized by the processing circuit 150 working in cooperation with each element of the media conveying device 100 based on a program stored in the storage device 140.

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 into 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 into the information processing device.

Then, 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 111 (S102). If no medium is placed on the placement table 103 (S102-No), the control unit 151 ends the medium reading process.

If a medium is placed on the table 103 (S102-Yes), the control unit 151 drives the 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 112, the feed roller 113, the brake roller 114, and the first to eighth transport rollers 117a-h, and feeds and transports the medium placed on the table 103 (S103).

Then, the determination unit 152 executes a determination process (S104). In the determination process, the determination unit 152 determines whether the transported medium is a bound medium, whether a double feed has occurred, and the like. The details of the determination process will be described later.

Then, the control unit 151 judges whether or not the conveyed medium is judged to be a binding medium in the judgment process (S105). If the conveyed medium is judged to be a binding medium (S105-Yes), the control unit 151 outputs a notification that the medium is a binding medium (S106). The control unit 151 outputs the notification that the medium is a binding medium by displaying it on the display device 106, and notifies the user. The control unit 151 may output a notification signal indicating the notification that the medium is a binding medium by transmitting it to the information processing device via the interface device 132, and notify the user. Next, the control unit 151 stops the motor 131 to stop the conveyance of the medium (S112), and ends the medium reading process. Note that outputting the notification that the medium is a binding medium and stopping the conveyance of the medium are examples of abnormal processing.

By stopping the transport of the medium when bound media is transported, the control unit 151 can prevent the occurrence of media jams and damage to the medium. The control unit 151 can also prevent staples or clips, etc., that have bound the medium from entering the transport path of the medium and damaging the glass surface of the imaging device 119, etc. This eliminates the need for the user to check whether the transported medium is stapled before transporting the medium, and the medium transport device 100 can improve user convenience and reduce the processing time of the medium reading process.

If it is determined that the transported medium is not a bound medium (S105-No), the control unit 151 determines whether the trailing edge of the medium has passed the imaging position of the imaging device 119 (S107). For example, the control unit 151 periodically acquires second medium signals from each second medium sensor 115, and determines that the trailing edge of the medium has passed the position of the second medium sensor 115 when the signal value of any of the second medium signals changes from a value indicating that the medium is present to a value indicating that the medium is not present. The control unit 151 determines that the trailing edge of the medium has passed the imaging position when a predetermined time has elapsed since the trailing edge of the medium passed the position of the second medium sensor 115. The predetermined time is set to the time it takes for the medium to be transported from the second medium sensor 115 to the imaging position plus a margin. If the trailing edge of the medium has not yet passed the imaging position (S107-No), the control unit 151 returns the process to S104 and repeats the processes of S104 to S107.

When the rear end of the medium has passed the imaging position (S107-Yes), the control unit 151 acquires an input image from the imaging device 119. The control unit 151 transmits the acquired input image to the information processing device via the interface device 132 (S108).

Then, the control unit 151 judges whether or not it has been judged in the judgment process that a multi-feed of media has occurred (S109). If it is judged that a multi-feed of media has occurred (S109-Yes), the control unit 151 outputs a notification that a multi-feed has occurred (S110). The control unit 151 outputs the notification that a multi-feed has occurred by displaying it on the display device 106, and notifies the user. The control unit 151 may output a notification signal indicating the notification that a multi-feed has occurred by transmitting it to the information processing device via the interface device 132, and notify the user. Next, the control unit 151 stops the motor 131 to stop the transport of the media (S112), and ends the media reading process. Note that outputting the notification that a multi-feed has occurred and stopping the transport of the media are examples of abnormality processing.

The control unit 151 may stop the motor 131 after a predetermined time has elapsed since the input image was transmitted in S108. The predetermined time is the time from when the medium that has passed the position of the imaging device 119 is discharged from the medium conveying device 100 to when it is placed on the discharge tray 104, plus a margin. This prevents the medium from remaining inside the medium conveying device 100 when the motor 131 is stopped.

Then, 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 111 (S111). If a medium is placed on the placement table 103 (S111-Yes), the control unit 151 returns the process to S104 and repeats the processes of S104 to S111. If a medium is not placed on the placement table 103 (S111-No), the control unit 151 stops the motor 131 (S112) and ends the medium reading process.

Figures 7 to 9 are flow diagrams showing an example of the operation of the determination process. The determination process is executed in S104 of Figure 6.

During the execution of the judgment process, the judgment unit 152 periodically determines whether each second medium sensor 115 has detected a medium in parallel with the judgment process. The judgment unit 152 periodically acquires a second medium signal from each second medium sensor 115, and when the signal value of each second medium signal changes from a value indicating the absence of a medium to a value indicating the presence of a medium, the judgment unit 152 determines that the second medium sensor 115 has detected a medium. Furthermore, during the execution of the judgment process, the judgment unit 152 periodically determines whether each ultrasonic sensor 116 has detected an overlap of media in parallel with the judgment process. The judgment unit 152 periodically acquires an ultrasonic signal from each ultrasonic sensor 116, and when the signal value of each ultrasonic signal is equal to or less than the overlap threshold, the judgment unit 152 determines that the ultrasonic sensor 116 has detected an overlap of media. The overlap threshold is set to a value between the signal value of the ultrasonic signal output when one PPC (Plain Paper Copier) sheet is conveyed and the signal value of the ultrasonic signal output when two PPC sheets are conveyed.

First, as shown in FIG. 7, the determination unit 152 waits until one of the multiple second media sensors 115 detects a medium (S201).

When any of the second media sensors 115 detects a medium, the determination unit 152 determines whether the ultrasonic sensor 116 downstream of the second media sensor 115 has detected an overlap of media (S202). The ultrasonic sensor 116 downstream of the second media sensor 115 is the ultrasonic sensor 116 arranged corresponding to the second media sensor 115, and is arranged so that at least a portion of the ultrasonic sensor 116 overlaps with the second media sensor 115 when viewed from the upstream side of the media transport direction A2. The determination unit 152 continues to determine whether the ultrasonic sensor 116 has detected an overlap of media until the first time has elapsed since the second media sensor 115 detected the medium or the ultrasonic sensor 116 detects an overlap of media. The first time is set to the time it takes for the medium to be transported from the second media sensor 115 to the ultrasonic sensor 116 plus a margin.

If the ultrasonic sensor 116 does not detect overlapping media before the first time has elapsed (S202-No), as shown in FIG. 8, the determination unit 152 determines whether the other second media sensor 115 has detected the media (S203). The other second media sensor 115 is a second media sensor 115 different from the second media sensor 115 that first detected the media. The determination unit 152 continues to determine whether the other second media sensors 115 have detected the media until the second time has elapsed since the first second media sensor 115 detected the media or until each of the other second media sensors 115 detects the media. The second time is set to the time difference between the times when the leading edge of the media reaches the position of each second media sensor 115 when the media is transported tilted at the maximum angle guaranteed by the media transport device 100, plus a margin.

If none of the other second media sensors 115 detects a medium before the second time has elapsed (S203-No), the determination unit 152 determines that the medium is a small medium such as a receipt and that multiple media feeds have not occurred (S204), and ends the determination process. A small medium is a medium in which the length of at least one side is shorter than the spacing between the multiple second media sensors 115.

If any of the other second media sensors 115 detects a medium before the second time has elapsed (S203-Yes), the determination unit 152 determines whether or not each ultrasonic sensor 116 downstream of the second media sensor 115 that detected the medium has detected overlapping media (S205). The determination unit 152 continues to determine whether or not each ultrasonic sensor 116 has detected overlapping media until the first time has elapsed since the other second media sensor 115 detected the medium or until each ultrasonic sensor 116 detects overlapping media.

If any of the ultrasonic sensors 116 detects overlapping media before the first time has elapsed (S205-Yes), the determination unit 152 determines that the media is a bound medium (S206) and ends the determination process. In this way, the determination unit 152 determines whether the media is a bound medium based on the detection results of the multiple second media sensors 115 and the multiple ultrasonic sensors 116. In particular, the determination unit 152 determines that the media is a bound medium when the first second media sensor 115 among the multiple second media sensors 115 detects the media, but after that second media sensor 115 detects the media, the ultrasonic sensor 116 downstream of that second media sensor 115 does not detect overlapping media and an ultrasonic sensor 116 other than that ultrasonic sensor 116 detects overlapping media.

If none of the ultrasonic sensors 116 detects overlapping media before the first time has elapsed (S205-No), the determination unit 152 determines that the media are normal media and that a double feed of media has not occurred (S207), and ends the determination process. A normal medium is a medium that is not bound media or card media, and is larger than a small medium.

If the ultrasonic sensor 116 downstream of the second media sensor 115 that first detected the medium detects overlapping media before the first time has elapsed (S202-Yes), as shown in FIG. 9, the determination unit 152 determines that the medium is not a bound medium (S208). In this way, the determination unit 152 determines that the medium is not a bound medium when the first second media sensor 115 among the multiple second media sensors 115 detects the medium, and then the ultrasonic sensor 116 downstream of the second media sensor 115 detects overlapping media.

Then, the determination unit 152 determines whether or not another second media sensor 115 has detected a medium (S209). The determination unit 152 continues to determine whether or not another second media sensor 115 has detected a medium until the second time has elapsed since the second media sensor 115 that first detected the medium detected the medium or until another second media sensor 115 detects the medium.

If none of the other second media sensors 115 detect the medium before the second time has elapsed (S209-No), the determination unit 152 determines that the medium is a card medium and that a duplicate feed of media has not occurred (S210), and ends the determination process. Because card media are thick, ultrasonic waves that pass through the card medium are significantly attenuated, and the signal value of the ultrasonic signal may fall below the overlap threshold. However, because card media are small in size, the determination unit 152 can accurately determine whether a duplicate feed of media has occurred or whether the card medium is being transported by determining whether multiple second media sensors 115 have detected the medium.

If any of the other second media sensors 115 detects a medium before the second time has elapsed (S209-Yes), the determination unit 152 determines whether or not each ultrasonic sensor 116 downstream of the second media sensor 115 that detected the medium has detected overlapping media (S211). The determination unit 152 continues to determine whether or not each ultrasonic sensor 116 has detected overlapping media until the first time has elapsed since the other second media sensor 115 detected the medium or until each ultrasonic sensor 116 detects overlapping media.

If any of the ultrasonic sensors 116 does not detect overlapping media before the first time has elapsed (S211-No), the determination unit 152 determines that a double feed of a normal medium and a small medium has occurred (S212) and ends the determination process. In this case, the determination unit 152 may determine that a sticker, stamp, or other attachment has been affixed to the medium and that a double feed of media has not occurred.

If all ultrasonic sensors 116 detect overlapping media before the first time has elapsed (S211-Yes), the determination unit 152 determines that a double feed of normal media has occurred (S213) and ends the determination process. In this way, the determination unit 152 determines that a double feed of media has occurred when the first second media sensor 115 among the multiple second media sensors 115 detects a medium, and then an ultrasonic sensor 116 downstream of that second media sensor 115 detects overlapping media, and an ultrasonic sensor 116 other than that ultrasonic sensor 116 also detects overlapping media. This allows the determination unit 152 to determine with high accuracy whether a double feed of media has occurred.

In addition, in S209, the determination unit 152 may determine that the medium is a card medium in S210 when the number of the second media sensors 115 that detected the medium is less than the specific number, and may proceed to S211 when the number of the second media sensors 115 that detected the medium is equal to or greater than the specific number. The specific number is preset to a number equal to or greater than 2. In that case, the determination unit 152 may determine whether or not each ultrasonic sensor 116 downstream of each second media sensor 115 that detected the medium detected an overlap of media even when the number of the second media sensors 115 that detected the medium is less than the specific number. The determination unit 152 determines that a double feed of small media has occurred when any of the ultrasonic sensors 116 downstream of each second media sensor 115 that detected the medium did not detect an overlap of media. On the other hand, the determination unit 152 determines that the medium is a card medium when all of the ultrasonic sensors 116 downstream of each second media sensor 115 that detected the medium detected an overlap of media. In this way, the determination unit 152 determines that the medium is a card medium when only a predetermined number of the ultrasonic sensors 116 among the multiple ultrasonic sensors 116 detect overlapping media. This allows the determination unit 152 to determine with high accuracy whether the medium being transported is a card medium or not.

The processes of S203 to S204 may be omitted, and in S205, the determination unit 152 may determine whether an ultrasonic sensor 116 other than the ultrasonic sensor 116 downstream of the second media sensor 115 that first detected the medium has detected overlapping media. Similarly, the processes of S209 to S210 may be omitted, and in S211, the determination unit 152 may determine whether an ultrasonic sensor 116 other than the ultrasonic sensor 116 downstream of the second media sensor 115 that first detected the medium has detected overlapping media. The processes of S209 to S211 may be omitted, and the determination unit 152 may determine that a double feed of media has occurred if the ultrasonic sensor 116 downstream of the second media sensor 115 that first detected the medium has detected overlapping media.

Below, we will explain the detection results of the second media sensor 115 and the ultrasonic sensor 116 when various types of media are transported in the example of the sensor arrangement shown in Figure 3.

Figures 10 (A) to (D) are schematic diagrams for explaining examples of sensor detection results when binding media are transported. Figure 10 (A) is a diagram seen from above showing a state in which binding media M1, which is made up of multiple media bound together, is fed and the leading end in the media transport direction A2 reaches the positions of the feed roller 113 and the brake roller 114. The binding media M1 is bound with one end (upper right end) on the downstream side in the media transport direction A2 set as the binding position S.

Figure 10 (B) is a diagram showing a state after time has passed since Figure 10 (A). Medium M2, which is stapled at the top of the binding medium M1 and is in contact with the feed roller 113, is pushed in the media transport direction A2 by the feed roller 113. On the other hand, medium M3 of the binding medium M1 that is not in contact with the feed roller 113 is subjected to a force in the opposite direction to the transport direction A2 by the brake roller 114 and is held in place. As a result, as shown in Figure 10 (B), medium M2 rotates around the binding position S so that the end (upper left end) opposite the binding position S in the width direction A4 advances in the media transport direction A2, and reaches the position of the second media sensor 115A arranged on the opposite side of the binding position S in the width direction A4. As a result, of the second media sensors 115A to C, the second media sensor 115A detects the medium first.

Figure 10 (C) is a diagram showing the state after further time has passed from Figure 10 (B). Medium M2 is pushed further in the medium transport direction A2 by the feed roller 113. As a result, as shown in Figure 10 (C), medium M2 reaches the position of ultrasonic sensor 116A downstream of second medium sensor 115A, which first detected the medium. In this state, only medium M2 has reached the position of ultrasonic sensor 116A, so ultrasonic sensor 116A does not detect the overlap of media.

As a result of medium M2 being pushed out in the media transport direction A2, medium M3 is subjected to a force pulling it in the media transport direction A2 from medium M2 at the binding position S. At the same time, medium M3 is subjected to a force in the opposite direction to the media transport direction A2 by the brake roller 114. As a result, as shown in FIG. 10(C), medium M3 rotates around the point of contact with the brake roller 114 so that the end (upper right end) on the binding position S side in the width direction A4 moves in the media transport direction A2.

Figure 10 (D) is a diagram showing the state after further time has passed since Figure 10 (C). Medium M2 is pushed further in the medium transport direction A2 by the feed roller 113. Also, medium M3 is pulled by medium M2 through the binding position S and proceeds in the medium transport direction A2 against the rotational force of the brake roller 114. As a result, medium M3 reaches the position of the ultrasonic sensor 116C arranged on the binding position S side in the width direction A4. Because medium M2 and medium M3 overlap at the position of the ultrasonic sensor 116C, the ultrasonic sensor 116C detects the overlap.

As shown in Figures 10 (A) to (D), when the binding medium M1 is transported, the second media sensor 115A, which is located on the opposite side of the binding position S in the width direction A4, detects the medium first. Then, the ultrasonic sensor 116A downstream of the second media sensor 115A that first detected the medium does not immediately detect the overlap of the media, but the ultrasonic sensor 116C, which is located on the binding position S side in the width direction A4, immediately detects the overlap of the media. Note that examples of the detection results of the second media sensor 115 and the ultrasonic sensor 116 when the binding medium is transported are not limited to the examples described above.

Figures 11 (A) and (B) are diagrams for explaining the detection results of the sensor when a binding medium M1 smaller than the example shown in Figure 10 is transported. Figure 11 (A) is a diagram showing a state corresponding to Figure 10 (B). As shown in Figure 11 (A), medium M2 bound at the top of binding medium M1 rotates around binding position S and reaches the position of second media sensor 115A arranged on the opposite side of binding position S in width direction A4. As a result, of second media sensors 115A to 115C, second media sensor 115A detects the medium first.

Figure 11 (B) is a diagram showing a state corresponding to Figure 10 (D). As shown in Figure 11 (B), medium M3 is pulled by medium M2 through binding position S and advances in medium transport direction A2 against the rotational force of brake roller 114. Because the width of medium M3 is smaller than that of the example shown in Figure 10 (D), as shown in Figure 11 (B), medium M3 does not reach the position of ultrasonic sensor 116C arranged on the binding position S side in width direction A4, but reaches the position of ultrasonic sensor 116B arranged in the center. Because medium M2 and medium M3 overlap at the position of ultrasonic sensor 116B, ultrasonic sensor 116B detects the overlap.

As shown in Figures 11 (A) and (B), when a small binding medium M1 is transported, the second medium sensor 115A, which is located on the opposite side of the binding position S in the width direction A4, detects the medium first. Then, the ultrasonic sensor 116A downstream of the second medium sensor 115A that first detected the medium does not immediately detect the overlap of the media, but the ultrasonic sensor 116B, which is located in the center in the width direction A4, immediately detects the overlap of the media.

As described with reference to Figures 10 and 11, different ultrasonic sensors 116 detect overlapping media depending on the size of the media. However, in either case, when the binding media is transported, the ultrasonic sensor 116 downstream of the second media sensor 115 that first detected the media does not immediately detect the overlapping media, but an ultrasonic sensor 116 different from that ultrasonic sensor 116 immediately detects the overlapping media. Therefore, the binding media is properly detected by the determination process of S202, S203, and S205.

Figures 12 (A) and (B) are schematic diagrams for explaining the detection results of the sensors when card media is transported. Figure 12 (A) is a diagram showing the state in which card media M4 has been fed and has reached the position of the second media sensor 115. As shown in Figure 12 (A), card media M4 has reached the position of the second media sensor 115B in the center in the width direction A4, so the second media sensor 115B detects the media.

Figure 12 (B) is a diagram showing the state after some time has passed since Figure 12 (A). As shown in Figure 12 (B), card medium M4 has reached the position of ultrasonic sensor 116B downstream of second medium sensor 115B, which detected the medium. Because card medium M4 is thicker than normal media, ultrasonic sensor 116B detects overlapping media. As shown in Figure 12 (B), card medium M4 is smaller in width direction A4 than normal media, so it does not reach the positions of second medium sensors 115A, C and ultrasonic sensors 116A, C, which are located on the end side in width direction A4. Therefore, second medium sensors 115A, C do not detect the medium, and ultrasonic sensors 116A, C do not detect overlapping media.

As explained using FIG. 12, when card medium M4 is transported, only the second medium sensor 115B located at the center in the width direction A4 detects the medium. Then, only the ultrasonic sensor 116B downstream of the second medium sensor 115B that detects the medium detects the overlap of the media.

In the example shown in FIG. 12, the width of the card medium M4 is smaller than the distance in the width direction A4 between adjacent second media sensors 115, so only one second media sensor 115 detects the medium, and only one ultrasonic sensor 116 detects the overlap of the media. However, depending on the relationship between the width of the card medium and the distance in the width direction of the second media sensor 115, multiple second media sensors 115 may detect the medium, or multiple ultrasonic sensors 116 may detect the overlap of the media. That is, when the card medium is transported, only a predetermined number of second media sensors 115 (one in the example shown in FIG. 12) including the second media sensor 115 that first detected the medium detects the medium, and only the ultrasonic sensor downstream of each second media sensor 115 that detected the medium detects the overlap of the media. The predetermined number is appropriately determined based on the relationship between the width of the card medium supported by the media transport device 100 and the distance in the width direction of the second media sensor 115. Therefore, the card medium is appropriately detected by S202 and S209 of the judgment process.

Figures 13 (A) and (B) are schematic diagrams for explaining the detection results of the sensors when a double feed occurs. Figure 13 (A) is a diagram showing a state in which multiple media M5 are transported overlapping each other and reach the position of the second media sensor 115. As shown in Figure 13 (A), since the medium M5 reaches the positions of the second media sensors 115A-C, the second media sensors 115A-C detect the medium at approximately the same time. In the following description, it is assumed that the second media sensor 115A detects the medium first.

Figure 13 (B) is a diagram showing the state after some time has passed since Figure 13 (A). As shown in Figure 13 (B), medium M5 is transported in the medium transport direction A2 in an overlapping state and reaches the positions of ultrasonic sensors 116A-C. As a result, ultrasonic sensors 116A-C each detect the overlap of the media.

As explained using FIG. 13, when a double feed occurs, the ultrasonic sensor 116A located downstream of the second media sensor 115A that first detected the media detects the overlap of the media, and the other ultrasonic sensors 116A and C also detect the overlap of the media. Therefore, the occurrence of a double feed is properly detected by the determination processes S202 and S211.

As described above, the medium conveying device 100 according to the embodiment uses multiple second medium sensors 115 and multiple ultrasonic sensors 116 to determine whether the medium being conveyed is a bound medium. This enables the medium conveying device 100 to properly detect the bound medium.

The media conveying device 100 detects the bound medium without detecting the lifting of the medium. This allows the media conveying device 100 to detect the bound medium with high accuracy. Furthermore, the media conveying device 100 detects the bound medium using only the media detection sensor and overlap detection sensor that are included in a typical media conveying device, making it possible to detect the bound medium while suppressing increases in device costs and component mounting space.

Figure 14 is a diagram illustrating an example of the arrangement of another second medium sensor 215 and ultrasonic sensor 216.

In the example shown in FIG. 14, instead of the multiple second medium sensors 115A-C and the multiple ultrasonic sensors 116A-C, multiple second medium sensors 215A-D and multiple ultrasonic sensors 216A-D are provided. Below, each second medium sensor 215A-D may be referred to as a second medium sensor 215. Also, each ultrasonic sensor 216A-D may be referred to as an ultrasonic sensor 216. Each second medium sensor 215 has a similar configuration to the second medium sensor 115. Also, each ultrasonic sensor 216 has a similar configuration to the ultrasonic sensor 116.

The four second media sensors 215A-D are spaced apart and arranged in a line along the width direction A4, which is perpendicular to the transport direction. Of the four second media sensors 215A-D, the second media sensors 215B and C, which are arranged in the center in the width direction A4, are arranged further downstream in the media transport direction A2 than the second media sensors 215A and D, which are arranged at the ends.

The four ultrasonic sensors 216A-D are arranged downstream of the second media sensors 215A-D in the media transport direction A2. Each ultrasonic sensor 216A-D is arranged so that at least a portion of it overlaps with the second media sensors 215A-D in the width direction A4, that is, so that at least a portion of it overlaps with the second media sensors 215A-D when viewed from the media transport direction A2. Of the four ultrasonic sensors 216A-D, ultrasonic sensors 216B and C, which are arranged in the center in the width direction A4, are arranged further downstream in the media transport direction A2 than the ultrasonic sensors 216A and D arranged on the end sides.

The number of second medium sensors 215 and ultrasonic sensors 216 is not limited to four, but may be any number equal to or greater than three.

In the example shown in FIG. 14, the second media sensors 215A and D, which are positioned outside the brake roller 114 in the width direction A4, are positioned downstream of the downstream end of the brake roller 114 in the media transport direction A2. This example is not limited to this, and the second media sensors 215A and D may be positioned upstream of the downstream end of the brake roller 114 in the media transport direction A2. In addition, the ultrasonic sensors 216A and D, which are located downstream of the second media sensors 215A and D, respectively, may be positioned upstream of the downstream end of the brake roller 114 in the media transport direction A2.

Figures 15 (A) to (D) are diagrams for explaining the detection results of the sensors when the binding medium is transported in the example of the sensor arrangement shown in Figure 14. Figure 15 (A) is a diagram showing the state in which the binding medium M1 is placed on one side (the binding position S side) on the loading table 103 and transported, and the leading edge in the media transport direction A2 reaches the positions of the feed roller 113 and the brake roller 114.

Figure 15 (B) is a diagram showing a state after time has passed since Figure 15 (A). Medium M2, which is stapled at the top of binding medium M1 and is in contact with the feed roller 113, is pushed in the media transport direction A2 by the feed roller 113. On the other hand, medium M3 of binding medium M1 that is not in contact with the feed roller 113 is subjected to a force in the opposite direction to the media transport direction A2 by the brake roller 114 and is held in place. As a result, as shown in Figure 15 (B), medium M2 rotates around the binding position S so that the end (upper left end) opposite the binding position S in the width direction A4 advances in the media transport direction A2, and reaches the position of the second media sensor 215B arranged in the center in the width direction A4. As a result, of the second media sensors 215A to D, the second media sensor 215B detects the medium first.

Figure 15 (C) is a diagram showing the state after further time has passed since Figure 15 (B). Medium M2 is pushed further in the medium transport direction A2 by the feed roller 113. As a result of medium M2 being pushed in the medium transport direction A2, medium M3 is subjected to a force pulling it in the medium transport direction A2 from medium M2 at the binding position S. At the same time, medium M3 is subjected to a force in the opposite direction to the medium transport direction A2 by the brake roller 114. As a result, as shown in Figure 15 (C), medium M3 rotates around the point of contact with the brake roller 114 so that the end (upper right end) on the binding position S side in the width direction A4 advances in the media transport direction A2.

Figure 15 (D) is a diagram showing the state after further time has passed since Figure 15 (C). Medium M2 is pushed further in the medium transport direction A2 by the feed roller 113. Also, medium M3 is pulled by medium M2 through the binding position S and proceeds in the medium transport direction A2 against the rotational force of the brake roller 114. As a result, medium M3 reaches the position of the ultrasonic sensor 216D arranged on the binding position S side in the width direction A4. Because medium M2 and medium M3 overlap at the position of the ultrasonic sensor 216D, the ultrasonic sensor 216D detects the overlap.

As shown in Figures 15 (A) to (D), when binding medium M1 is transported, the second media sensor 215B detects the medium first. Then, the ultrasonic sensor 216B downstream of the second media sensor 215B that first detected the medium does not immediately detect the overlap of the media, but the ultrasonic sensor 216D arranged on the binding position S side in the width direction A4 immediately detects the overlap of the media.

In particular, in this embodiment, the second media sensors 215A, D and the ultrasonic sensors 216A, D arranged at both ends of the width direction A4 are arranged upstream of the second media sensors 215B, C and the ultrasonic sensors 216B, C arranged in the center. As described above, when the binding medium M1 is transported toward the binding position S, the leading edge of the separated medium M2 is first detected by the second media sensors 215B, C arranged in the center. On the other hand, since the binding position S of the binding medium M1 faces the ultrasonic sensor 216D arranged at the end of the width direction A4, the overlap of the binding medium M1 is detected by the ultrasonic sensor 216D. In this embodiment, by arranging the ultrasonic sensor 216D arranged at the end of the width direction A4 on the upstream side, the determination unit 152 can detect the overlap of the media earlier and stop the transport of the media earlier, thereby suppressing the occurrence of damage to the media. In addition, by arranging the ultrasonic sensors 216B and C located at the center of the width direction A4 on the downstream side, it takes a sufficient amount of time for the leading edge of the medium M3 remaining on the upstream side to reach the position of the ultrasonic sensors 216B and C located at the center. Therefore, the determination unit 152 can prevent the medium from being damaged by erroneously determining that a double feed of unstitched media has occurred even though bound media is being transported, without stopping the transport of the media.

In addition, by reducing the spacing between the multiple second media sensors 215 and the multiple ultrasonic sensors 216, the media conveying device can detect the binding medium well even if the size of the binding medium in the width direction A4 is small, thereby improving the detection accuracy of the binding medium.

Figures 16 (A) and (B) are schematic diagrams for explaining the detection results of the sensors when card media is transported in the example of the sensor arrangement shown in Figure 14. Figure 16 (A) is a diagram showing the state in which card media M4 has been fed and has reached the position of the second media sensor 215. As shown in Figure 16 (A), card media M4 has reached the positions of the second media sensors 215B and C in the center in the width direction A4, so the second media sensors 215B and C detect the media.

Figure 16 (B) is a diagram showing the state after some time has passed since Figure 16 (A). In Figure 16 (B), card medium M4 has reached the positions of ultrasonic sensors 216B and C downstream of second media sensors 215B and C that detected the medium. Because card medium M4 is thicker than normal media, ultrasonic sensors 216B and C each detect the overlap of media. On the other hand, because card medium M4 is smaller than normal media in width direction A4, it does not reach the positions of second media sensors 215A, D and ultrasonic sensors 216A, D. Therefore, second media sensors 215A, D do not detect the medium, and ultrasonic sensors 216A, D do not detect the overlap of media.

As explained using FIG. 16, when card medium M4 is transported, only the second media sensors 215B and C located at the center in the width direction A4 detect the medium. Then, only the ultrasonic sensors 216B and C downstream of the second media sensors 215B and C that detected the medium detect overlapping media. In other words, when card media is transported, only a predetermined number of second media sensors 215 (two in the example shown in FIG. 16) including the second media sensor 215 that first detected the medium detect the medium, and only the ultrasonic sensors 216 downstream of each second media sensor 215 that detected the medium detect overlapping media.

In this way, the media conveying device is able to properly detect the bound media even when the multiple second media sensors 215 and the multiple ultrasonic sensors 216 are positioned offset in the media conveying direction A2.

In the above embodiment, an ultrasonic sensor is used as the overlap detection sensor, but a thickness sensor that detects the thickness of the medium may be used as the overlap detection unit. The thickness sensor is placed at the position where each ultrasonic sensor is placed. The thickness sensor includes a pair of a light emitter and a light receiver provided on one side of the medium transport path, and a pair of a light emitter and a light receiver provided on the other side. The thickness sensor detects the distance from each pair to each surface of the medium based on the time from when one pair irradiates one surface of the medium with light to when it receives the reflected light, and the time from when the other pair irradiates the other surface of the medium with light to when it receives the reflected light. The thickness sensor generates a signal indicating the subtraction value obtained by subtracting each detected distance from the distance between the two pairs as a thickness signal corresponding to the thickness of the medium.

In this case, in the determination process, the determination unit 152 periodically acquires a thickness signal from each thickness sensor, and when the signal value of each thickness signal is equal to or greater than the thickness threshold, determines that the thickness sensor has detected an overlap of media. The thickness threshold is set to a value between the signal value of the thickness signal output when one PPC sheet is conveyed and the signal value of the thickness signal output when two PPC sheets are conveyed.

In addition, in the above-described embodiment, the feed roller 113 is disposed above the brake roller 114 and feeds the media placed on the mounting table 103 in order from the top, but the feed roller may be disposed below the brake roller so that the media placed on the mounting table is fed in order from the bottom.

Figure 17 is a diagram showing a schematic configuration of a processing circuit 350 in a medium conveying device according to another embodiment. The processing circuit 350 is used in place of the processing circuit 150 of the medium conveying device 100, and executes the medium reading process. The processing circuit 350 includes a control circuit 351 and a determination circuit 352. Each of these components may be configured as an independent integrated circuit, microprocessor, firmware, etc.

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 111, and a judgment result in the judgment process from the judgment circuit 352, and controls the motor 131 based on the received signals and judgment results. The control circuit 351 also receives an input image from the imaging device 119, stores it in the storage device 140, and transmits it to the information processing device via the interface device 132.

The judgment circuit 352 is an example of a judgment unit, and has the same function as the judgment unit 152. The judgment circuit 352 receives a second medium signal and an ultrasonic signal from the second medium sensor 115 and the ultrasonic sensor 116, respectively. Based on the received signals, the judgment circuit 352 judges whether the medium is a bound medium and whether a double feed of media has occurred, and outputs the judgment result to the control circuit 351.

As described above, the media conveying device is capable of properly detecting the binding media even when using the processing circuit 350.

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-described embodiments and modifications may be implemented in appropriate combinations within the scope of the present invention.

REFERENCE SIGNS LIST 100 Medium conveying device 113 Feeding roller 115 Second medium sensor 116 Ultrasonic sensor 151 Control unit 152 Determination unit

Claims (8)

a separation roller for separating the media;
a plurality of medium detection sensors disposed downstream of the separation roller in a medium transport direction and along a direction perpendicular to the transport direction;
a plurality of overlap detection sensors disposed downstream of each of the medium detection sensors in the transport direction for detecting overlap of the medium;
a determination unit that determines whether the medium is a bound medium based on detection results of the plurality of medium detection sensors and the plurality of overlap detection sensors;
A control unit that stops conveyance of the medium when the medium is determined to be a binding medium,
the determination unit determines that the medium is a bound medium when, after a medium detection sensor that first detects a medium among the plurality of medium detection sensors detects the medium, an overlap detection sensor downstream of the medium detection sensor does not detect an overlap of media, and an overlap detection sensor different from the medium detection sensor detects an overlap of media.
A medium transport device comprising: The medium conveying device according to claim 1, wherein the determination unit determines that the medium is not a bound medium when an overlap detection sensor downstream of a media detection sensor that first detects a medium detects the medium after the first media detection sensor detects the medium. The medium conveying device according to claim 2, wherein the determination unit determines that a duplicated medium feed has occurred when an overlap detection sensor downstream of a media detection sensor that first detects a medium detects the medium, and an overlap detection sensor different from the overlap detection sensor also detects an overlap of media, after the first media detection sensor detects the medium. The medium conveying device according to claim 2 or 3, wherein the determination unit determines that the medium is a card medium when only a predetermined number of the overlap detection sensors among the plurality of overlap detection sensors detect an overlap of the medium. A medium transport device according to any one of claims 1 to 4, wherein, of the plurality of medium detection sensors, a medium detection sensor arranged at the center in a direction perpendicular to the transport direction is arranged further downstream in the transport direction than the medium detection sensors arranged at the ends. The medium transport device according to claim 5, wherein the overlap detection sensor corresponding to the medium detection sensor arranged in the center is arranged further downstream in the transport direction than the overlap detection sensor corresponding to the medium detection sensor arranged on the end side. A control method for a medium transport device having a separation roller for separating a medium, a plurality of medium detection sensors arranged downstream of the separation roller in a medium transport direction and along a direction perpendicular to the transport direction, and a plurality of overlap detection sensors arranged downstream of each of the medium detection sensors in the transport direction for detecting overlapping of the media, the method comprising the steps of:
determining whether the medium is a bound medium based on detection results of the plurality of medium detection sensors and the plurality of overlap detection sensors;
If the medium is determined to be a bound medium, stopping the transport of the medium ;
In the determination, if a media detection sensor that first detects a medium among the plurality of media detection sensors detects the medium, and then an overlap detection sensor downstream of the media detection sensor does not detect an overlap of media, and an overlap detection sensor other than the first overlap detection sensor detects an overlap of media, the medium is determined to be a bound medium.
A control method comprising: A control program for a medium transport device having a separation roller for separating a medium, a plurality of medium detection sensors arranged downstream of the separation roller in a medium transport direction and along a direction perpendicular to the transport direction, and a plurality of overlap detection sensors arranged downstream of each of the medium detection sensors in the transport direction for detecting overlapping of the media, the control program comprising:
determining whether the medium is a bound medium based on detection results of the plurality of medium detection sensors and the plurality of overlap detection sensors;
when the medium is determined to be a bound medium, stopping the transport of the medium ;
In the determination, if a media detection sensor that first detects a medium among the plurality of media detection sensors detects the medium, and then an overlap detection sensor downstream of the media detection sensor does not detect an overlap of media, and an overlap detection sensor other than the first overlap detection sensor detects an overlap of media, the medium is determined to be a bound medium.
A control program comprising:

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