Medium conveyance device, determination method, and control program

Abstract

To provide a medium conveyance device capable of properly determining a state of a medium while suppressing increase in device cost, and to provide a determination method and a control program.SOLUTION: A medium conveyance device includes: a driving signal output part for outputting a driving signal at predetermined timing; a first sound wave transmitter for outputting sound waves at least including audible sound and ultrasonic waves based on the driving signal outputted at predetermined timing; a first sound wave receiver for outputting a first sound wave signal according to the received sound waves; a second sound wave transmitter for outputting sound waves at least including audible sound and ultrasonic waves based on the driving signal outputted at predetermined timing; a second sound wave receiver for outputting a second sound wave signal according to the received sound waves; a determination part for determining the state of the medium based on the first sound wave signal and the second sound wave signal; and an output part for outputting the first sound wave signal and the second sound wave signal to the determination part alternately at different timing.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In a medium transport device such as a scanner that captures an image of a medium while transporting it, it is necessary to properly determine the position of the medium so that the image can be properly captured from the leading edge to the trailing edge of the medium. Generally, the medium transport device has a function of detecting whether a double feed, in which multiple media are transported together, has occurred, and automatically stopping the transport of the media when a double feed has occurred.

[0003] An apparatus for detecting a plurality of documents in a document transport system is disclosed (see US Pat. No. 5,399,633). The apparatus comprises a first transmitter for emitting a first signal during a first interval, a first sensor for detecting the first signal, a second transmitter for emitting a second signal during a second interval, and a second sensor for detecting the second signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-175570 A Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable for a medium conveying device to be able to appropriately determine the state of the medium while suppressing increases in device costs.

[0006] An object of the present invention is to provide a medium conveying device, a determination method, and a control program that are capable of appropriately determining the state of a medium while suppressing an increase in device costs. [Means for solving the problem]

[0007] A medium transport device according to one aspect of the present invention comprises a transport section which transports a medium along a transport path, a drive signal output section which outputs a drive signal at a predetermined timing, a first sound wave transmitter which outputs sound waves including at least audible sound or ultrasonic sound based on the drive signal output at the predetermined timing, a first sound wave receiver which is arranged opposite the first sound wave transmitter across the transport path and which outputs a first sound wave signal corresponding to the received sound waves, a second sound wave transmitter which outputs sound waves including at least audible sound or ultrasonic sound based on the drive signal output at the predetermined timing, a second sound wave receiver which is arranged opposite the second sound wave transmitter across the transport path and which outputs a second sound wave signal corresponding to the received sound waves, a judgment section which judges the state of the medium based on the first sound signal and the second sound signal, and an output section which outputs the first sound signal and the second sound signal to the judgment section at mutually different timings.

[0008] In addition, a determination method according to one aspect of the present invention includes a transport unit transporting a medium along a transport path, a drive signal output unit outputting a drive signal at a predetermined timing, a first sound wave transmitter outputting sound waves including at least audible sound or ultrasonic wave based on the drive signal output at the predetermined timing, a first sound wave receiver arranged opposite the first sound wave transmitter across the transport path outputting a first sound wave signal corresponding to the received sound waves, a second sound wave transmitter outputting sound waves including at least audible sound or ultrasonic wave based on the drive signal output at the predetermined timing, a second sound wave receiver arranged opposite the second sound wave transmitter across the transport path outputting a second sound wave signal corresponding to the received sound waves, an output unit outputting the first sound wave signal and the second sound wave signal at different timings from each other, and determining the state of the medium based on the first sound wave signal and the second sound wave signal output by the output unit.

[0009] In addition, a control program according to one aspect of the present invention is a control program for a medium conveying device having a conveying section that conveys a medium along a conveying path, a drive signal output section that outputs a drive signal at a predetermined timing, a first sound wave transmitter that outputs sound waves including at least audible sound or ultrasonic sound based on the drive signal output at the predetermined timing, a first sound wave receiver that is arranged opposite the first sound wave transmitter across the conveying path and outputs a first sound wave signal corresponding to the received sound waves, a second sound wave transmitter that outputs sound waves including at least audible sound or ultrasonic sound based on the drive signal output at the predetermined timing, a second sound wave receiver that is arranged opposite the second sound wave transmitter across the conveying path and outputs a second sound wave signal corresponding to the received sound waves, and an output section that outputs the first sound signal and the second sound signal at different timings from each other, and causes the medium conveying device to determine the state of the medium based on the first sound signal and the second sound signal output by the output section. Effect of the Invention

[0010] According to the present invention, the medium conveying device, the determination method, and the control program are capable of appropriately determining the state of the medium while suppressing an increase in device costs. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a medium conveying device 100 according to an embodiment. [Diagram 2] 2 is a diagram for explaining a transport path inside the medium transport device 100. FIG. [Diagram 3] 1 is a schematic diagram for explaining a first acoustic wave sensor 115 and the like. FIG. [Figure 4] 1 is a block diagram showing a schematic configuration of a medium conveying device 100. FIG. [Diagram 5] FIG. 2 is a diagram showing a schematic configuration of a storage device 140 and a processing circuit 150. [Figure 6] 10 is a flowchart illustrating an example of the operation of a medium reading process. [Figure 7] (A) and (B) are graphs showing the characteristics of the magnitude of sound waves. [Figure 8] 10 is a flowchart illustrating an example of an operation of a sound wave signal reception process. [Figure 9] FIG. 2 is a schematic diagram for explaining a plurality of drive signal amplifiers. [Figure 10] FIG. 2 is a schematic diagram for explaining a plurality of sound wave signal amplifiers. [Figure 11] FIG. 13 is a schematic diagram for explaining a drive signal delay circuit 426. [Figure 12] FIG. 13 is a schematic diagram for explaining a sound wave signal delay circuit 526. [Figure 13] FIG. 13 is a diagram showing a schematic configuration of a processing circuit 650 in another medium conveying device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0013] FIG. 1 is a perspective view showing a medium conveying device 100 configured as 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 or the like. The medium also includes a medium to which an attachment such as a label (sticker) or a small piece of paper (photograph, clipping, postage stamp, revenue stamp, etc.) is affixed. The medium conveying device 100 may be a facsimile, a copier, a multifunction printer (MFP, Multifunction Peripheral), or the like. Note that the medium being conveyed may not be an original document, but may be a printed object, etc., and the medium conveying device 100 may be a printer, etc.

[0014] 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.

[0015] The second housing 102 is disposed above the medium conveying device 100, and engages with the first housing 101 by a hinge so as to be openable and closable when a medium is jammed, when the inside of the medium conveying device 100 is cleaned, and the like.

[0016] The placement table 103 engages with the first housing 101 so that the transported media can be placed thereon. The placement table 103 is provided on the side of the first housing 101 on the media supply side so that it can move in a substantially vertical direction (height direction) A1 by a motor (not shown). The placement table 103 is disposed at a lower end position so that the media can be easily placed on it when the media is not being transported, and when the media is being transported, the placement table 103 rises to a position where the uppermost medium placed on the placement table 103 comes into contact with a pick roller (described later). The discharge table 104 is formed on the second housing 102 so that it can hold the discharged media, and it stacks the discharged media.

[0017] The operation device 105 has an input device such as a button and an interface circuit for acquiring a signal from the input device, accepts an input operation by a user, and outputs an operation signal according to the input operation by the user. The display device 106 has a display including a liquid crystal, an organic EL (Electro-Luminescence), or the like, and an interface circuit for outputting image data to the display, and displays the image data on the display.

[0018] 1, arrow A2 indicates the medium transport direction, arrow A3 indicates the medium discharge direction, and arrow A4 indicates the width direction perpendicular to the medium transport direction. In the following, upstream refers to the upstream of the medium transport direction A2 or the medium discharge direction A3, and downstream refers to the downstream of the medium transport direction A2 or the medium discharge direction A3.

[0019] FIG. 2 is a diagram for explaining a transport path inside the medium transport device 100. As shown in FIG.

[0020] The transport path inside the medium transport device 100 includes a medium sensor 111, a pick roller 112, a feed roller 113, a separation roller 114, a first ultrasonic sensor 115, a second ultrasonic sensor 116, first to eighth transport rollers 117a-h, first to eighth driven rollers 118a-h, and an imaging device 119.

[0021] The pick roller 112, the feed roller 113, the separation roller 114, the first to eighth transport rollers 117a-h, and the first to eighth driven rollers 118a-h are an example of a transport unit, and are arranged along the transport path of the medium to transport the medium along the transport path. Note that the number of each of the pick roller 112, the feed roller 113, the separation roller 114, the first to eighth transport 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 separation roller 114, the first to eighth transport rollers 117a-h, and / or the first to eighth driven rollers 118a-h are arranged at intervals in the width direction A4.

[0022] The medium conveying device 100 has a so-called U-turn path. The surface of the first housing 101 facing the second housing 102 forms a first guide 101a of the medium conveying path, and the surface of the second housing 102 facing the first housing 101 forms a second guide 102a of the medium conveying path.

[0023] The media sensor 111 is disposed on the mounting table 103, that is, upstream of the feed roller 113 and the separation roller 114, and detects the state of the medium on the mounting table 103. The 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 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 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 media sensor 111.

[0024] Pick roller 112 is provided in second housing 102, and comes into contact with a medium placed on placement table 103 elevated to approximately the same height as the medium transport path, to feed the medium downstream.

[0025] The feed roller 113 is provided in the second housing 102 downstream of the pick roller 112, and feeds the medium placed on the placement table 103 and fed by the pick roller 112 further downstream. The separation roller 114 is provided in the first housing 101 facing the feed roller 113. The feed roller 113 and the separation roller 114 perform a medium separation operation, separate the media, and feed them one by one. The feed roller 113 is provided above the separation roller 114, and the medium conveying device 100 feeds the media by a so-called top-take method.

[0026] The first and second sonic sensors 115 and 116 are disposed downstream of the feed roller 113 and the separation roller 114 and upstream of the first conveyor roller 117a and the first driven roller 118a. The first and second sonic sensors 115 and 116 are disposed side by side with a gap in the width direction A4. The first and second sonic sensors 115 and 116 may be disposed at any position downstream of the feed roller 113 and the separation roller 114 and upstream of the eighth conveyor roller 117h and the eighth driven roller 118h. The first and second sonic sensors 115 and 116 may be disposed side by side with a gap in the medium conveying direction A2. The first and second sonic sensors 115 and 116 may be disposed to have any positional relationship.

[0027] The first sonic sensor 115 includes a first sonic transmitter 115a and a first sonic receiver 115b. The first sonic transmitter 115a and the first sonic receiver 115b are disposed near the transport path of the medium, facing each other across the transport path. The second sonic sensor 116 includes a second sonic transmitter 116a and a second sonic receiver 116b. The second sonic transmitter 116a and the second sonic receiver 116b are disposed near the transport path of the medium, facing each other across the transport path. Details of the first sonic sensor 115 and the second sonic sensor 116 will be described later.

[0028] 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 separation roller 114, and transport the medium fed by the feed roller 113 and the separation roller 114 downstream. The first to eighth transport rollers 117a-h and the first to eighth driven rollers 118a-h are disposed opposite each other with the medium transport path in between.

[0029] The imaging device 119 is disposed downstream of the second conveying roller 117b and the second driven roller 118b and upstream of the third conveying roller 117c and the third driven roller 118c. The imaging device 119 may be disposed at any position downstream of the feed roller 113 and the separation roller 114 and upstream of the eighth conveying roller 117h and the eighth driven roller 118h. The imaging device 119 includes a first imaging device 119a and a second imaging device 119b. The first imaging device 119a and the second imaging device 119b are disposed near the medium conveying path and facing each other across the conveying path.

[0030] 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.

[0031] 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 A / D converts the electrical signal output from the imaging element. The second imaging device 119b captures the back side of the medium being transported to generate an input image and output it.

[0032] The medium conveying device 100 may be arranged 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.

[0033] The medium placed on the mounting table 103 is transported between the first guide 101a and the second guide 102a in the medium transport direction A2 by the rotation of the pick roller 112 and the feed roller 113 in the medium feed directions A5 and A6, respectively. Meanwhile, when multiple media are placed on the mounting table 103, only the media in contact with the feed roller 113 is separated from the media placed on the mounting table 103 by the rotation of the separation roller 114 in the direction A7 opposite to the medium feed direction.

[0034] 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 arrows A8-A9, and is imaged by the imaging device 119. Furthermore, the medium is discharged onto the discharge table 104 by the rotation of the third to eighth transport rollers 117c-h in the directions of arrows A10-A15, respectively.

[0035] FIG. 3 is a schematic diagram for explaining the first acoustic wave sensor 115 and the second acoustic wave sensor 116. As shown in FIG.

[0036] As shown in FIG. 3, the medium conveying device 100 further includes a drive signal generator 121, a drive signal amplifier 122, an output unit 123, a sound wave signal amplifier 124, an A / D converter 125, and the like.

[0037] The drive signal generator 121 is an example of a drive signal output unit, and outputs a drive signal at a predetermined timing. The drive signal generator 121 outputs a drive signal to the drive signal amplifier 122 according to control from a predetermined circuit described later. The drive signal is a signal for driving the first sonic wave oscillator 115a and the second sonic wave oscillator 116a, and is a clock signal that changes ON / OFF at regular intervals.

[0038] The drive signal amplifier 122 is an example of an amplifier, and amplifies the drive signal output from the drive signal generator 121 and outputs the amplified signal to the first sound wave oscillator 115a and the second sound wave oscillator 116a.

[0039] The first sonic wave transmitter 115a outputs sonic waves based on the drive signal output from the drive signal amplifier 122, i.e., based on the drive signal output from the drive signal generator 121 at a predetermined timing. The sonic waves include at least audible sounds or ultrasonic waves. The frequency of the audible sounds is 20 Hz or more and 20 kHz or less, and the frequency of the ultrasonic waves is greater than 20 kHz and less than 300 MHz. The sonic waves may further include sonic waves less than 20 Hz and / or sonic waves greater than 300 MHz. On the other hand, the first sonic wave receiver 115b receives the sonic waves output by the first sonic wave transmitter 115a and passing through the medium, and generates and outputs a first sonic wave signal, which is an electric signal corresponding to the received sonic waves. The first sonic wave signal indicates the magnitude of the sonic waves received by the first sonic wave receiver 115b, i.e., the magnitude of the sonic waves passing through the medium transported by the transport unit. In addition, the first acoustic signal may indicate, in addition to or instead of the magnitude of the acoustic waves received by the first acoustic receiver 115b, the magnitude of the phase shift of the acoustic waves received by the first acoustic receiver 115b relative to the phase of the acoustic waves emitted by the first acoustic transmitter 115a.

[0040] The second sonic wave transmitter 116a outputs sonic waves based on the drive signal output from the drive signal amplifier 122, i.e., based on the drive signal output from the drive signal generator 121 at a predetermined timing. The sonic waves include audible sounds and ultrasonic waves. The frequency of the audible sounds is 20 Hz or more and 20 kHz or less, and the frequency of the ultrasonic waves is greater than 20 kHz and less than 300 MHz. On the other hand, the second sonic wave receiver 116b receives the sonic waves output by the second sonic wave transmitter 116a and passing through the medium, and generates and outputs a second sonic wave signal, which is an electrical signal corresponding to the received sonic waves. The second sonic wave signal indicates the magnitude of the sonic waves received by the second sonic wave receiver 116b, i.e., the magnitude of the sonic waves passing through the medium transported by the transport unit. In addition, the second sonic signal may indicate, in addition to or instead of the magnitude of the sonic waves received by the second sonic receiver 116b, the magnitude of the phase shift of the sonic waves received by the second sonic receiver 116b relative to the phase of the sonic waves emitted by the second sonic wave transmitter 116a.

[0041] The first sound wave transmitter 115a and the second sound wave transmitter 116a output sound waves based on a common (same) drive signal output from the drive signal generator 121. As shown in FIG. 3, the distance D1 between the first sound wave transmitter 115a and the first sound wave receiver 115b is different from the distance D2 between the second sound wave transmitter 116a and the second sound wave receiver 116b. Therefore, the timings at which sound waves simultaneously output from the first sound wave transmitter 115a and the second sound wave transmitter 116a based on the same drive signal reach the first sound wave receiver 115b and the second sound wave receiver 116b are different from each other. Therefore, the timing at which the first sound wave receiver 115b outputs the first sound wave signal is different from the timing at which the second sound wave receiver 116b outputs the second sound wave signal.

[0042] For example, each sonic sensor is arranged so that the difference between the distance D1 between the first sonic transmitter 115a and the first sonic receiver 115b and the distance D2 between the second sonic transmitter 116a and the second sonic receiver 116b is 5 mm or more. The timing at which the sonic waves output from each sonic transmitter reach each sonic receiver is shifted by the value obtained by dividing the difference between the distance D1 and the distance D2 by the speed of sound, so the difference in time from when each sonic transmitter outputs a sonic wave to when each sonic receiver receives the sonic wave is 10 μsec or more. In other words, the time difference between the timing at which the first sonic receiver 115b outputs a first sonic signal based on a drive signal output at a predetermined timing and the timing at which the second sonic receiver 116b outputs a second sonic signal based on that drive signal is 10 μsec or more. Therefore, the medium conveying device 100 can fully determine the state of the medium at each of the positions of the multiple acoustic sensors by using each of the multiple acoustic signals output by the multiple acoustic receivers.

[0043] The output device 123 is an example of an output unit. The first sound signal output from the first sound receiver 115b and the second sound signal output from the second sound receiver 116b are input to the output device 123. The output device 123 switches the signal to be output and outputs either the first sound signal output from the first sound receiver 115b or the second sound signal output from the second sound receiver 116b. As described above, the timing at which the first sound receiver 115b outputs the first sound signal and the timing at which the second sound receiver 116b outputs the second sound signal are different from each other, so that the first sound signal and the second sound signal are input to the output device 123 at different timings. The output device 123 is provided to output the first sound signal when the first sound signal is input, and to output the second sound signal when the second sound signal is input. In the above example, the time difference between the timing at which the first sound wave signal is input to output device 123 and the timing at which the second sound wave signal is input is 10 μsec or more, so that output device 123 can reliably distinguish between the first sound wave signal and the second sound wave signal and output them.

[0044] In addition, since the timings at which the first and second sound signals are input to the output device 123 are different from each other, the output device 123 may combine and output the input first and second sound signals instead of switching the signal to be output. However, by switching the signal to be output, the output device 123 can output the first and second sound signals without causing mutual interference even when the first and second sound signals are input in an overlapping manner.

[0045] In this way, the distance D1 between the first sound wave transmitter 115a and the first sound wave receiver 115b is different from the distance D2 between the second sound wave transmitter 116a and the second sound wave receiver 116b, so that the output device 123 outputs the first sound wave signal and the second sound wave signal at different timings. This allows the processing circuit to appropriately determine the state of the medium by using each of the first sound wave signal and the second sound wave signal.

[0046] The sound wave signal amplifier 124 is an example of an amplifier, and amplifies the first sound wave signal and the second sound wave signal output from the output unit 123 and outputs the amplified signal to the A / D converter 125 .

[0047] The A / D converter 125 samples the analog first and second sound signals output from the sound signal amplifier 124 at regular intervals, digitally converts the samples to generate digital first and second sound signals, and outputs the digital first and second sound signals to the processing circuit. That is, the output unit 123 outputs the first and second sound signals to the processing circuit via the sound signal amplifier 124 and the A / D converter 125. The sound signal amplifier 124 outputs the first and second sound signals to the processing circuit via the A / D converter 125.

[0048] In this way, in the medium conveying device 100, the drive signal generator 121 that generates the drive signals input to the multiple sonic sensors is shared, and the A / D converter 125 and processing circuit that process the sonic signals output from the multiple sonic sensors are shared. This allows the medium conveying device 100 to reduce the device cost and weight while having multiple sonic sensors.

[0049] Generally, when a sonic transmitter is driven for a long time, the sonic transmitter generates heat, and the waveform of the sonic wave output from the sonic transmitter is distorted due to the influence of the heat. Therefore, it is desirable that the period during which a drive signal (pulse) is input to the sonic transmitter is set as short as possible within a range in which the sonic receiver can properly detect the sonic waves output from the sonic transmitter and the processing circuit can properly process the sonic signal output from the sonic receiver. In other words, it is preferable that the length of the sonic signal output from the sonic receiver is the minimum length that the processing circuit can process. In that case, if the first sonic signal and the second sonic signal are input to the output device at the same time, the output device cannot output the first sonic signal and the second sonic signal without mutual interference and with a length that the processing circuit can process.

[0050] In the medium conveying device 100, the first and second sound signals are input to the output device 123 at different timings. Therefore, the output device 123 can output the first and second sound signals to the processing circuit without mutual interference and with a length that the processing circuit can process. Therefore, the processing circuit can determine the state of the medium based on each of the first and second sound signals.

[0051] FIG. 4 is a block diagram showing a schematic configuration of the medium conveying device 100. As shown in FIG.

[0052] In addition to the components described above, 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.

[0053] The motor 131 includes one or more motors, and rotates the pick roller 112, the feeding roller 113, the separation roller 114, and the first to eighth transport rollers 117a-h to feed and transport the medium in response to a control signal from the processing circuit 150. The first to eighth driven rollers 118a-h may be provided so as to rotate by the driving force from the motor, rather than being driven to rotate in accordance with the rotation of the transport rollers.

[0054] 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, for example, a personal computer, a mobile information terminal, etc.) to transmit and receive input 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 in accordance with a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network).

[0055] The storage device 140 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. The storage device 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 portable recording medium using a known setup program or the like. The portable recording medium is, for example, a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or the like.

[0056] The processing circuit 150 operates based on a program previously stored in the storage device 140. The processing circuit 150 is, for example, a CPU (Central Processing Unit). As the processing circuit 150, a DSP (digital signal processor), an LSI (large scale integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or the like may be used.

[0057] The processing circuit 150 is connected to the operation device 105, the display device 106, the medium sensor 111, the imaging device 119, the drive signal generator 121, the A / D converter 125, 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 acquire an input image, and transmits the acquired input image to the information processing device via the interface device 132. The processing circuit 150 also controls the drive signal generator 121 to cause the first sound wave transmitter 115a and the second sound wave transmitter 116a to output sound waves, and determines the state of the medium based on the first sound wave signal and the second sound wave signal received from the A / D converter 125.

[0058] FIG. 5 is a diagram showing a schematic configuration of the storage device 140 and the processing circuit 150. As shown in FIG.

[0059] 5, the storage device 140 stores 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 program 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.

[0060] FIG. 6 is a flowchart showing an example of the operation of the medium reading process.

[0061] An example of the operation of the medium reading process of the medium conveying device 100 will be described below with reference to the flowchart shown in Fig. 6. Note that the flow of the operation described below is executed mainly by the processing circuit 150 in cooperation with each element of the medium conveying device 100 based on a program stored in advance in the storage device 140.

[0062] First, the control unit 151 waits until a user inputs an instruction to read a medium using the operation device 105 or an information processing device, and an operation signal instructing the user to read a medium is received from the operation device 105 or the interface device 132 (step S101).

[0063] Next, control unit 151 acquires a medium signal from medium sensor 111, and determines whether or not a medium is placed on placement table 103 based on the acquired medium signal (step S102). If no medium is placed on placement table 103, control unit 151 returns the process to step S101 and waits until a new operation signal is received from operation device 105 or interface device 132.

[0064] On the other hand, when a medium is placed on the placement table 103, the control unit 151 drives a motor for moving the placement table 103 to move the placement 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 separation roller 114, the first to eighth transport rollers 117a-h, and / or the first to eighth driven rollers 118a-h. In this way, the control unit 151 feeds and transports the medium placed on the placement table 103 (step S103).

[0065] Next, the processing circuit 150 executes a sonic signal reception process (step S104). In the sonic signal reception process, the determination unit 152 receives the first sonic signal output from the first sonic receiver 115b and the second sonic signal output from the second sonic receiver 116b from the A / D converter 125. The sonic signal reception process will be described later.

[0066] Next, the determination unit 152 determines whether or not a double feed of media has occurred as a state of the media (step S105). The determination unit 152 determines whether or not a double feed of media has occurred based on the first sound signal output from the first sound receiver 115b and the second sound signal output from the second sound receiver 116b. When the magnitude of the sound wave indicated by the first sound signal is less than the first sound threshold, the determination unit 152 determines that an overlap of media has occurred at the position of the first sound sensor 115. On the other hand, when the magnitude of the sound wave indicated by the first sound signal is equal to or greater than the first sound threshold, the determination unit 152 determines that an overlap of media has not occurred at the position of the first sound sensor 115. Furthermore, when the magnitude of the sound wave indicated by the second sound signal is less than the second sound threshold, the determination unit 152 determines that an overlap of media has occurred at the position of the second sound sensor 116. On the other hand, when the magnitude of the sound waves indicated by the second sound signal is equal to or greater than the second sound threshold, the determining unit 152 determines that no overlap of media has occurred at the position of the second sound sensor 116 .

[0067] 7(A) and 7(B) are graphs 700 and 710 showing characteristics of the magnitude of sound waves shown in the first sound signal. Note that the characteristics of the second sound signal are similar to those of the first sound signal, so in the following, only the characteristics of the first sound signal will be described as a representative example.

[0068] The horizontal axis of graphs 700 and 710 indicates time, and the vertical axis indicates the magnitude of the sound wave indicated by the first sound signal. Graph 700 indicates the magnitude of the sound wave when one PPC sheet is conveyed, and graph 710 indicates the magnitude of the sound wave when two PPC sheets are conveyed overlapping each other. In graphs 700 and 710, the leading edge of the sheet reaches the position of the first sound wave sensor 115 at time T1, and the trailing edge of the sheet passes the position of the first sound wave sensor 115 at time T2. When a sheet is present at the position of the first sound wave sensor 115, the sound wave output from the first sound wave generator 115a is attenuated by the sheet. Therefore, as shown in graph 700, when a sheet is present at the position of the first sound wave sensor 115, the magnitude of the sound wave is reduced compared to when no medium is present at the position of the first sound wave sensor 115. Furthermore, when two sheets of paper are present at the position of the first ultrasonic sensor 115, the sound waves output from the first ultrasonic transmitter 115a are further attenuated by the air layer between the two sheets of paper. Therefore, as shown in graph 710, when two sheets of paper are present at the position of the first ultrasonic sensor 115, the magnitude of the sound waves is reduced compared to when only one sheet of paper is present at the position of the first ultrasonic sensor 115.

[0069] The first acoustic threshold S1 is set to a value between the magnitude of the sound waves indicated by the first acoustic signal when one sheet of paper is present at the position of the first acoustic sensor 115 and the magnitude of the sound waves indicated by the first acoustic signal when two sheets of paper are present at the position of the first acoustic sensor 115. Similarly, the second acoustic threshold S2 is set to a value between the magnitude of the sound waves indicated by the second acoustic signal when one sheet of paper is present at the position of the second acoustic sensor 116 and the magnitude of the sound waves indicated by the second acoustic signal when two sheets of paper are present at the position of the second acoustic sensor 116. The determination unit 152 can appropriately determine whether or not media overlap has occurred at the position of each acoustic sensor by comparing the magnitude of the sound waves indicated by each acoustic signal with each acoustic threshold.

[0070] When a sheet of paper is present at each sonic sensor, the phase of the sound waves output from each sonic transmitter is shifted by the sheet of paper. Therefore, when a sheet of paper is present at each sonic sensor, the phase shift of the sound waves is greater than when no medium is present at each sonic sensor. Furthermore, when two sheets of paper are present at each sonic sensor, the phase shift of the sound waves output from each sonic transmitter is further increased by the air layer between the two sheets of paper. Therefore, when two sheets of paper are present at each sonic sensor, the phase shift of the sound waves is greater than when only one sheet of paper is present at each sonic sensor.

[0071] Therefore, the determination unit 152 may determine whether or not an overlap of media has occurred based on the magnitude of the phase shift of the sound waves indicated by the first and second sound signals. In this case, the determination unit 152 determines that an overlap of media has occurred at the position of the first sound sensor 115 when the magnitude of the phase shift indicated by the first sound signal is greater than the first phase threshold. On the other hand, the determination unit 152 determines that an overlap of media has not occurred at the position of the first sound sensor 115 when the magnitude of the phase shift indicated by the first sound signal is equal to or less than the first phase threshold. Furthermore, the determination unit 152 determines that an overlap of media has occurred at the position of the second sound sensor 116 when the magnitude of the phase shift indicated by the second sound signal is greater than the second phase threshold. On the other hand, the determination unit 152 determines that an overlap of media has not occurred at the position of the second sound sensor 116 when the magnitude of the phase shift indicated by the second sound signal is equal to or less than the second phase threshold.

[0072] The first phase threshold is set to a value between the magnitude of the phase shift indicated by the first acoustic signal when one sheet of paper is present at the position of the first acoustic sensor 115 and the magnitude of the phase shift indicated by the first acoustic signal when two sheets of paper are present at the position of the first acoustic sensor 115. The second phase threshold is set to a value between the magnitude of the phase shift indicated by the second acoustic signal when one sheet of paper is present at the position of the second acoustic sensor 116 and the magnitude of the phase shift indicated by the second acoustic signal when two sheets of paper are present at the position of the second acoustic sensor 116. In this case as well, the determination unit 152 can appropriately determine whether or not media overlap has occurred.

[0073] The determination unit 152 may also determine whether or not an overlap of media has occurred based on both the magnitude of the sound waves and the magnitude of the phase shift of the sound waves. For example, the determination unit 152 determines that an overlap of media has occurred when both the magnitude of the sound waves and the phase shift of the sound waves indicate that an overlap of media has occurred, and determines that an overlap of media has not occurred when either of them indicates that an overlap of media has not occurred. In this case, the determination unit 152 determines that an overlap of media has occurred at the position of the first sound sensor 115 when the magnitude of the sound waves indicated by the first sound signal is less than the first sound threshold and the magnitude of the phase shift is greater than the first phase threshold. On the other hand, the determination unit 152 determines that an overlap of media has not occurred at the position of the first sound sensor 115 when the magnitude of the sound waves indicated by the first sound signal is equal to or greater than the first sound threshold or when the magnitude of the phase shift is equal to or less than the first phase threshold. Furthermore, when the magnitude of the sound waves indicated by the second sound signal is less than the second sound threshold and the magnitude of the phase shift is greater than the second phase threshold, the determination unit 152 determines that an overlap of media has occurred at the position of the second sound sensor 116. On the other hand, when the magnitude of the sound waves indicated by the second sound signal is equal to or greater than the second sound threshold or when the magnitude of the phase shift is equal to or less than the second phase threshold, the determination unit 152 determines that an overlap of media has not occurred at the position of the second sound sensor 116. In this case, the determination unit 152 can more accurately determine whether or not an overlap of media has occurred.

[0074] The determination unit 152 may change the first and second sound thresholds based on the magnitude of the phase shift indicated in the first sound signal and the magnitude of the phase shift indicated in the second sound signal, respectively. For example, the determination unit 152 sets the first sound threshold when the magnitude of the phase shift indicated in the first sound signal is greater than the first phase threshold to a value greater than the first sound threshold when the magnitude is equal to or less than the first phase threshold. The determination unit 152 sets the second sound threshold when the magnitude of the phase shift indicated in the second sound signal is greater than the second phase threshold to a value greater than the second sound threshold when the magnitude is equal to or less than the second phase threshold. In this case, the determination unit 152 can also more accurately determine whether or not the media overlap.

[0075] The determination unit 152 determines that a double feed of media has occurred when an overlap of media has occurred at least one of the positions of the first sonic sensor 115 and the second sonic sensor 116. On the other hand, the determination unit 152 determines that a double feed of media has not occurred when an overlap of media has not occurred at both the positions of the first sonic sensor 115 and the second sonic sensor 116. Note that the determination unit 152 may determine that a medium with a sticker affixed thereto is being transported and that a double feed of media has not occurred when an overlap of media has occurred at one of the positions of the first sonic sensor 115 and the second sonic sensor 116 and an overlap of media has not occurred at the other.

[0076] When the determination unit 152 determines that a duplicated medium feed has occurred, the control unit 151 executes an abnormality process (step S106) and ends the series of steps. As the abnormality process, the control unit 151 stops the motor 131 to stop the feeding and transporting of the medium by the transport unit. As the abnormality process, the control unit 151 notifies the user by displaying information indicating that a duplicated medium feed has occurred on the display device 106 or by transmitting the information to the information processing device via the interface device 132. As the abnormality process, the control unit 151 may eject the medium currently being transported and then stop the medium reading process. As the abnormality process, the control unit 151 may drive the motor 131 and control the transport unit to reverse the medium, return it to the placement table 103, and then re-feed it. This eliminates the need for the user to re-mount the medium on the placement table 103 and re-feed it, and the control unit 151 can improve the user's convenience.

[0077] On the other hand, if it is determined in step S105 that a duplicated medium feed has not occurred, the determination unit 152 determines whether or not the leading edge of the medium has reached the imaging start position as the state of the medium (step S107). The determination unit 152 determines whether or not the leading edge of the medium has reached the imaging start position based on the first acoustic signal output from the first acoustic receiver 115b and the second acoustic signal output from the second acoustic receiver 116b.

[0078] If the magnitude of the sound waves indicated in the previously received first sound signal is greater than the third sound threshold and the magnitude of the sound waves indicated in the currently received first sound signal is equal to or less than the third sound threshold, the determination unit 152 determines that the tip of the medium has reached the position of the first sound sensor 115. If the magnitude of the sound waves indicated in the previously received second sound signal is greater than the fourth sound threshold and the magnitude of the sound waves indicated in the currently received second sound signal is equal to or less than the fourth sound threshold, the determination unit 152 determines that the tip of the medium has reached the position of the second sound sensor 116.

[0079] As shown in Fig. 7(A) and Fig. 7(B), the third sound threshold S3 and the fourth sound threshold S4 are set to values ​​greater than the first sound threshold S1 and the second sound threshold S2, respectively. The third sound threshold S3 is set to a value between the magnitude of the sound wave indicated by the first sound signal when no paper is present at the position of the first sound sensor 115 and the magnitude of the sound wave indicated by the first sound signal when a sheet of paper is present at the position of the first sound sensor 115. The fourth sound threshold S4 is set to a value between the magnitude of the sound wave indicated by the second sound signal when no paper is present at the position of the second sound sensor 116 and the magnitude of the sound wave indicated by the second sound signal when a sheet of paper is present at the position of the second sound sensor 116.

[0080] The determination unit 152 may determine whether the leading edge of the medium has reached the position of the first ultrasonic sensor 115 and whether the leading edge of the medium has reached the position of the second ultrasonic sensor 116 based on the magnitude of the phase shift of the sound waves indicated in the first ultrasonic signal and the second ultrasonic signal. In this case, the determination unit 152 determines that the leading edge of the medium has reached the position of the first ultrasonic sensor 115 when the magnitude of the phase shift indicated in the previously received first ultrasonic signal is less than the third phase threshold and the magnitude of the phase shift indicated in the currently received first ultrasonic signal is equal to or greater than the third phase threshold. The determination unit 152 also determines that the leading edge of the medium has reached the position of the second ultrasonic sensor 116 when the magnitude of the phase shift indicated in the previously received second ultrasonic signal is less than the fourth phase threshold and the magnitude of the phase shift indicated in the currently received second ultrasonic signal is equal to or greater than the fourth phase threshold.

[0081] The third and fourth phase thresholds are set to values ​​smaller than the first and second phase thresholds, respectively. The third phase threshold is set to a value between the magnitude of the phase shift indicated by the first acoustic signal when no paper is present at the position of the first acoustic sensor 115 and the magnitude of the phase shift indicated by the first acoustic signal when a sheet of paper is present at the position of the first acoustic sensor 115. The fourth phase threshold is set to a value between the magnitude of the phase shift indicated by the second acoustic signal when no paper is present at the position of the second acoustic sensor 116 and the magnitude of the phase shift indicated by the second acoustic signal when a sheet of paper is present at the position of the second acoustic sensor 116.

[0082] The determination unit 152 may also determine whether or not the leading edge of the medium has reached the position of each sonic sensor based on both the magnitude of the sound waves and the magnitude of the phase shift of the sound waves. For example, the determination unit 152 determines that the medium has reached the position of the sonic sensor when either the magnitude of the sound waves or the phase shift of the sound waves indicates that the medium is present, and determines that the medium has not reached the position of the sonic sensor when both indicate that the medium is not present. In this case, the determination unit 152 can more accurately determine whether or not the leading edge of the medium has reached the position of each sonic sensor.

[0083] The determination unit 152 may change the third sound threshold and the fourth sound threshold based on the magnitude of the phase shift indicated by the first sound signal and the magnitude of the phase shift indicated by the second sound signal, respectively. For example, the determination unit 152 sets the third sound threshold when the magnitude of the phase shift indicated by the first sound signal is greater than the third phase threshold to a value greater than the third sound threshold when the magnitude is equal to or less than the third phase threshold. The determination unit 152 also sets the fourth sound threshold when the magnitude of the phase shift indicated by the second sound signal is greater than the fourth phase threshold to a value greater than the fourth sound threshold when the magnitude is equal to or less than the fourth phase threshold. In this case, the determination unit 152 can more accurately determine whether the leading edge of the medium has reached the position of each sound sensor.

[0084] The determination unit 152 determines that the leading edge of the medium has reached the imaging start position when the leading edge of the medium has reached at least one of the positions of the first ultrasonic sensor 115 or the second ultrasonic sensor 116, or when a first predetermined time has elapsed thereafter. The first predetermined time is set to the time required for the medium to move from the position of the first ultrasonic sensor 115 or the position of the second ultrasonic sensor 116 to a predetermined position upstream of the imaging device 119.

[0085] Furthermore, the determination unit 152 may use a second medium sensor (not shown) different from the first sonic sensor 115 and the second sonic sensor 116 to determine whether the leading edge of the medium has reached the imaging start position. In this case, the second medium sensor is disposed at an arbitrary position downstream of the feed roller 113 and the separation roller 114 and upstream of the imaging device 119. For example, the second medium sensor includes a light emitter and a light receiver provided on one side of the medium transport path, and a light guide tube provided at a position facing the light emitter and the light receiver across the medium transport path. The light emitter is an LED (Light Emitting Diode) or the like, and irradiates light toward the medium transport path. On the other hand, the light receiver is a photodiode or the like, and receives the light irradiated by the light emitter and guided by the light guide tube. The second medium sensor generates and outputs a second medium signal whose signal value changes depending on whether a medium is present or not at the position of the medium sensor based on the intensity of the light received by the light receiver.

[0086] The determination unit 152 determines that the leading edge of the medium has reached the position of the second medium sensor when the signal value of the second medium signal changes from a value indicating a state in which the medium is not present to a state in which the medium is present. The determination unit 152 determines that the leading edge of the medium has reached the imaging start position when the leading edge of the medium has reached the position of the second medium sensor, or when a second predetermined time has elapsed thereafter. The second predetermined time is set to the time required for the medium to move from the position of the second medium sensor to a predetermined position upstream of the imaging device 119. Alternatively, the determination unit 152 may determine that the leading edge of the medium has reached the imaging start position when a predetermined time has elapsed since feeding of the medium began.

[0087] If the leading edge of the medium has not yet reached the image capture start position, the control unit 151 does not execute any particular process and moves the process to step S109.

[0088] On the other hand, when the leading edge of the medium reaches the image capture start position, the control unit 151 causes the image capture device 119 to start capturing an image of the medium (step S108).

[0089] Next, the determination unit 152 determines whether or not the rear end of the medium has passed the imaging position as the state of the medium (step S109). The determination unit 152 determines whether or not the rear end of the medium has passed the imaging position based on the first acoustic signal output from the first acoustic receiver 115b and the second acoustic signal output from the second acoustic receiver 116b.

[0090] If the magnitude of the sound waves indicated in the previously received first sound signal is equal to or less than the third sound threshold and the magnitude of the sound waves indicated in the currently received first sound signal is greater than the third sound threshold, the determination unit 152 determines that the rear end of the medium has passed the position of the first sound sensor 115. Furthermore, if the magnitude of the sound waves indicated in the previously received second sound signal is equal to or less than the fourth sound threshold and the magnitude of the sound waves indicated in the currently received second sound signal is greater than the fourth sound threshold, the determination unit 152 determines that the rear end of the medium has passed the position of the second sound sensor 116.

[0091] The determination unit 152 may determine whether the rear end of the medium has passed the position of the first ultrasonic sensor 115 and whether the rear end of the medium has passed the position of the second ultrasonic sensor 116 based on the magnitude of the phase shift of the sound waves indicated by the first and second ultrasonic signals. In this case, the determination unit 152 determines that the front end of the medium has reached the position of the first ultrasonic sensor 115 when the magnitude of the phase shift indicated by the previously received first ultrasonic signal is equal to or greater than the third phase threshold and the magnitude of the phase shift indicated by the currently received first ultrasonic signal is less than the third ultrasonic threshold. The determination unit 152 also determines that the front end of the medium has reached the position of the second ultrasonic sensor 116 when the magnitude of the phase shift indicated by the previously received second ultrasonic signal is equal to or greater than the fourth phase threshold and the magnitude of the phase shift indicated by the currently received second ultrasonic signal is less than the fourth ultrasonic threshold.

[0092] The determination unit 152 may also determine whether or not the rear end of the medium has passed the position of each sonic sensor based on both the magnitude of the sound wave and the magnitude of the phase shift of the sound wave. For example, if both the magnitude of the sound wave and the phase shift of the sound wave indicate that the medium is not present, the determination unit 152 determines that the medium has passed the position of the sonic sensor, and if either indicates that the medium is present, the determination unit 152 determines that the medium has not passed the position of the sonic sensor. In this case, the determination unit 152 can more accurately determine whether or not the rear end of the medium has passed each sonic sensor.

[0093] The determination unit 152 determines that the rear end of the medium has passed the imaging position when a third predetermined time has elapsed since the rear end of the medium passed both the position of the first ultrasonic sensor 115 and the position of the second ultrasonic sensor 116. The third predetermined time is set to the time required for the medium to move from the position of the first ultrasonic sensor 115 or the position of the second ultrasonic sensor 116 to the imaging position of the imaging device 119.

[0094] Furthermore, the determination unit 152 may use the second medium sensor to determine whether or not the rear end of the medium has passed the imaging position. In this case, the determination unit 152 determines that the rear end of the medium has passed the position of the second medium sensor when the signal value of the second medium signal changes from a value indicating a state in which the medium is present to a state in which the medium is not present. The determination unit 152 determines that the rear end of the medium has passed the imaging position when a fourth predetermined time has elapsed since the rear end of the medium passed the position of the second medium sensor. The fourth predetermined time is set to the time required for the medium to move from the position of the second medium sensor to the imaging position of the imaging device 119. Alternatively, the determination unit 152 may determine that the rear end of the medium has passed the imaging position when a predetermined time has elapsed since feeding of the medium began.

[0095] If the rear end of the medium has not yet passed the imaging position, the control unit 151 returns the process to step S104, and repeats the processes from step S104 onwards.

[0096] On the other hand, when the rear end of the medium has passed the imaging position, the control unit 151 determines that the entire medium has been imaged. The control unit 151 acquires an input image from the imaging device 119, and outputs the acquired input image by transmitting it to the information processing device via the interface device 132 (step S110).

[0097] Next, control unit 151 determines whether or not a medium remains on mounting table 103 based on the medium signal received from medium sensor 111 (step S111). If a medium remains on mounting table 103, control unit 151 returns the process to step S104, and repeats the processes from step S104 onwards.

[0098] On the other hand, if there are no media remaining on the placement table 103, the control unit 151 stops the motor 131. As a result, the control unit 151 stops the pick roller 112, the feeding roller 113, the separation roller 114, the first to eighth conveying rollers 117a-h, and / or the first to eighth driven rollers 118a-h (step S112). With the above, the control unit 151 ends the series of steps.

[0099] The processes in steps S105 and S106 may be omitted, and the determination unit 152 may not need to determine whether or not a multiple feeding of media has occurred as the state of the media.

[0100] The determination unit 152 may also determine whether a medium jam has occurred as the state of the medium. The determination unit 152 determines whether a medium jam has occurred based on the first sound signal output from the first sound receiver 115b and the second sound signal output from the second sound receiver 116b. The determination unit 152 determines that a medium jam has occurred when the leading edge of the medium does not reach either the position of the first sound sensor 115 or the position of the second sound sensor 116 within a predetermined time after the start of feeding of the medium. When the determination unit 152 determines that a medium jam has occurred, the control unit 151 stops the motor 131 as an abnormality process and stops the feeding and conveying of the medium by the conveying unit. The control unit 151 also notifies the user as an abnormality process by displaying information indicating that a medium jam has occurred on the display device 106 or transmitting the information to the information processing device via the interface device 132. As a result, when a medium jam occurs, medium conveying device 100 can prevent damage to the medium caused by continuing to apply a load to the medium.

[0101] The determination unit 152 may also determine whether or not a skew of the medium has occurred as the state of the medium. The determination unit 152 determines whether or not a skew of the medium has occurred based on the first sonic signal output from the first sonic receiver 115b and the second sonic signal output from the second sonic receiver 116b. The determination unit 152 determines that a skew of the medium has occurred when the leading edge of the medium reaches one of the positions of the first sonic sensor 115 and the second sonic sensor 116 and does not reach the other within a predetermined time. When the determination unit 152 determines that a skew of the medium has occurred, the control unit 151 stops the motor 131 as an abnormality process and stops the feeding and conveying of the medium by the conveying unit. The control unit 151 also notifies the user as an abnormality process by displaying information indicating that a skew of the medium has occurred on the display device 106 or transmitting the information to the information processing device via the interface device 132. As a result, when the medium becomes skewed, the medium conveying device 100 can prevent the medium from colliding with the side wall of the conveying path and causing damage to the medium.

[0102] 8 is a flowchart showing an example of the operation of the sound wave signal reception process. The flow of the operation shown in FIG. 8 is executed in step S104 of the flowchart shown in FIG.

[0103] First, the control unit 151 controls the drive signal generator 121 to output a drive signal for a predetermined period. As a result, the control unit 151 drives the first sound wave sensor 115 and the second sound wave sensor 116 for the predetermined period, causing the first sound wave transmitter 115a and the second sound wave transmitter 116a to output sound waves (step S201). The predetermined period may be set to a period shorter than the time difference between the timing at which the output unit 123 receives the first sound wave signal generated based on the drive signal output at a predetermined timing and the timing at which the output unit 123 receives the second sound wave signal generated based on the drive signal. The predetermined period is set to, for example, a time shorter than 10 μsec.

[0104] Next, the determination unit 152 waits until a first time has elapsed since the control unit 151 caused the drive signal generator 121 to output a drive signal (step S202). The first time is set in advance to the time from when the control unit 151 caused the drive signal generator 121 to output a drive signal to when the A / D converter 125 outputs a first sound wave signal generated based on the drive signal.

[0105] Next, the determination unit 152 receives the signal output from the A / D converter 125. As a result, the determination unit 152 receives the first sound wave signal generated based on the drive signal output from the drive signal generator 121 in step S201 (step S203).

[0106] Next, the determination unit 152 waits until a second time has elapsed since the control unit 151 caused the drive signal generator 121 to output a drive signal (step S204). The second time is set in advance to a time from when the control unit 151 caused the drive signal generator 121 to output a drive signal to when the A / D converter 125 outputs a second sound wave signal generated based on the drive signal.

[0107] Next, the determination unit 152 receives the signal output from the A / D converter 125. As a result, the determination unit 152 receives the second sound wave signal generated based on the drive signal output from the drive signal generator 121 in step S201 (step S205), and ends the series of steps.

[0108] As described above in detail, the medium conveying device 100 standardizes the drive system of each sonic sensor and the signal processing system of each sonic signal output from each sonic sensor by making the timing of output of the sonic signal from the multiple sonic sensors using a common drive signal different from each other. This allows the medium conveying device 100 to use a common drive signal generator 121 and A / D converter 125 for the multiple sonic sensors, and can suppress an increase in parts costs. In addition, the medium conveying device 100 can drive multiple sonic sensors collectively by controlling one drive signal generator 121, and can collectively acquire multiple sonic signals output from the multiple sonic sensors from one A / D converter 125. Therefore, the medium conveying device 100 can simplify the drive process of each sonic sensor and the signal processing of each sonic signal output from each sonic sensor, and suppress an increase in development costs related to each process. Therefore, the medium conveying device 100 can appropriately determine the state of the medium while suppressing an increase in the device cost.

[0109] In particular, the medium conveying device 100 outputs each sound signal at a different timing because the distance D1 between the first sound wave transmitter 115a and the first sound wave receiver 115b is different from the distance D2 between the second sound wave transmitter 116a and the second sound wave receiver 116b. This allows the medium conveying device 100 to determine the state of the medium using each sound signal without having special components for differentiating the output timing of each sound signal, making it possible to further suppress increases in device costs.

[0110] FIG. 9 is a schematic diagram for explaining a first drive signal amplifier 222a and a second drive signal amplifier 222b in a medium conveyance device according to another embodiment.

[0111] The medium conveying device according to this embodiment has the same components as the medium conveying device 100. However, as shown in Fig. 9, the medium conveying device according to this embodiment has a first drive signal amplifier 222a and a second drive signal amplifier 222b instead of the drive signal amplifier 122. The drive signal generator 121 outputs drive signals to each of the first drive signal amplifier 222a and the second drive signal amplifier 222b.

[0112] The first drive signal amplifier 222a is an example of a first amplifier, and amplifies the drive signal output from the drive signal generator 121 and outputs it to the first sound wave oscillator 115a. The second drive signal amplifier 222b is an example of a second amplifier, and amplifies the drive signal output from the drive signal generator 121 and outputs it to the second sound wave oscillator 116a.

[0113] The medium conveying device 100 amplifies the drive signals input to the first sound wave generator 115a and the second sound wave generator 116a using one drive signal amplifier 122, thereby reducing the number of components in the medium conveying device 100 and the weight and cost of the device. However, the medium conveying device 100 distributes the drive signal output from the drive signal amplifier 122 so that it is input to both the first sound wave generator 115a and the second sound wave generator 116a. Since the drive signal is attenuated when distributed, the drive signal amplifier 122 needs to greatly amplify the drive signal taking into account the attenuation. If the drive signal is greatly amplified, the waveform of the drive signal may be distorted and the amount of EMI (Electromagnetic Interference) generated by the drive signal may increase.

[0114] In the medium conveying device according to the present embodiment, the drive signals input to the first sonic generator 115a and the second sonic generator 116a are amplified using separate drive signal amplifiers, so that it is not necessary to distribute the drive signals amplified using each drive signal amplifier. Therefore, each drive signal amplifier can amplify the drive signal to an appropriate level, improving the quality of the waveform of the drive signal and reducing the amount of EMI generated by the drive signal.

[0115] As described above in detail, the medium conveying device is capable of appropriately determining the state of the medium while suppressing increases in device costs, even when the drive signals input to the first sound wave oscillator 115a and the second sound wave oscillator 116a are amplified using separate drive signal amplifiers.

[0116] FIG. 10 is a schematic diagram for explaining a first sound signal amplifier 324a and a second sound signal amplifier 324b in a medium conveying device according to yet another embodiment.

[0117] The medium conveying device according to this embodiment has each of the components of the medium conveying device 100. However, as shown in Fig. 10, the medium conveying device according to this embodiment has a first sonic signal amplifier 324a and a second sonic signal amplifier 324b instead of the sonic signal amplifier 124. The first sonic receiver 115b outputs a first sonic signal to the first sonic signal amplifier 324a, and the second sonic receiver 116b outputs a second sonic signal to the second sonic signal amplifier 324b.

[0118] The first sonic signal amplifier 324a is an example of a first amplifier, and amplifies the first sonic signal output from the first sonic receiver 115b and outputs it to the output device 123. The second sonic signal amplifier 324b is an example of a second amplifier, and amplifies the second sonic signal output from the second sonic receiver 116b and outputs it to the output device 123. The first sonic signal output from the first sonic signal amplifier 324a and the second sonic signal output from the second sonic signal amplifier 324b are input to the output device 123. The output device 123 switches the signal to be output, and outputs either the first sonic signal output from the first sonic signal amplifier 324a or the second sonic signal output from the second sonic signal amplifier 324b to the A / D converter 125. Alternatively, the output unit 123 synthesizes the input first and second sound wave signals and outputs the result to the A / D converter 125.

[0119] The medium conveying device 100 amplifies the first and second sound signals input to the A / D converter 125 using one sound signal amplifier 124, thereby reducing the number of components in the medium conveying device 100 and reducing the weight and cost of the device. However, since the sound signal amplifier 124 amplifies the first and second sound signals switched and output by the output device 123 at a predetermined timing, there is a possibility that the sound signal amplifier 124 may also amplify noise generated when the output device 123 switches signals. On the other hand, in the medium conveying device according to this embodiment, the first sound signal amplifier 324a and the second sound signal amplifier 324b amplify the first and second sound signals before inputting them to the output device 123, and therefore do not amplify noise generated when the output device 123 switches signals. Therefore, the medium conveying device according to this embodiment can improve the quality of the first and second sound signals.

[0120] Furthermore, in the medium conveying device according to the present embodiment, the distance on the signal line between each sound signal receiver and each sound signal amplifier is shortened by arranging each sound signal amplifier between each sound signal receiver and each sound signal amplifier between the sound signal receiver and each sound signal amplifier. Therefore, the noise generated on the signal line between each sound signal receiver and each sound signal amplifier and input to each sound signal amplifier is reduced. Therefore, the medium conveying device according to the present embodiment can suppress the amplification of noise and improve the quality of the first sound signal and the second sound signal.

[0121] In this embodiment, instead of the drive signal amplifier 122, a first drive signal amplifier 222a and a second drive signal amplifier 222b may be used.

[0122] As described above in detail, the medium conveying device is capable of appropriately determining the condition of the medium while suppressing increases in device costs, even when the first and second acoustic signals are amplified using separate acoustic signal amplifiers.

[0123] FIG. 11 is a schematic diagram for explaining a drive signal delay circuit 426 in a medium conveyance device according to yet another embodiment.

[0124] The medium conveying device according to this embodiment has each of the components of the medium conveying device 100. However, as shown in FIG. 11, the medium conveying device according to this embodiment has a second sonic sensor 416 instead of the second sonic sensor 116, and further has a drive signal delay circuit 426. The second sonic sensor 416 includes a second sonic transmitter 416a and a second sonic receiver 416b. The drive signal amplifier 122 outputs an amplified drive signal to the first sonic transmitter 115a and the drive signal delay circuit 426.

[0125] The drive signal delay circuit 426 is an example of a signal delay circuit. The drive signal delay circuit 426 is a delay circuit including a capacitor, a resistor, and the like, and is disposed between the drive signal amplifier 122 (a signal distributor to the first sound wave oscillator 115a and the second sound wave oscillator 416a) and the second sound wave oscillator 416a. The drive signal delay circuit 426 delays the drive signal input from the drive signal amplifier 122 by a predetermined time and outputs the delayed signal to the second sound wave oscillator 416a. The predetermined time is set to, for example, 10 μsec.

[0126] The second sonic wave transmitter 416a and the second sonic wave receiver 416b have the same configuration and function as the second sonic wave transmitter 116a and the second sonic wave receiver 116b. However, the second sonic sensor 416 is disposed so that the distance between the second sonic wave transmitter 416a and the second sonic wave receiver 416b is the same as the distance D1 between the first sonic wave transmitter 115a and the first sonic wave receiver 115b.

[0127] The drive signal delay circuit may be disposed between the drive signal amplifier 122 (signal distribution unit) and the first sound wave oscillator 115a, and may delay the drive signal input from the drive signal amplifier 122 and output it to the first sound wave oscillator 115a. When the first drive signal amplifier 222a and the second drive signal amplifier 222b are provided as shown in FIG. 9, the drive signal delay circuit may be disposed between the drive signal generator 121 (signal distribution unit) and the second drive signal amplifier 222b, and may delay the drive signal input from the drive signal generator 121 and output it to the second drive signal amplifier 222b. Alternatively, the drive signal delay circuit may be disposed between the second drive signal amplifier 222b and the second sound wave oscillator 416a, and may delay the drive signal input from the second drive signal amplifier 222b and output it to the second sound wave oscillator 416a. Alternatively, the drive signal delay circuit may be disposed between the drive signal generator 121 (signal distribution unit) and the first drive signal amplifier 222a, and may delay the drive signal input from the drive signal generator 121 and output it to the first drive signal amplifier 222a. Alternatively, the drive signal delay circuit may be disposed between the first drive signal amplifier 222a and the first acoustic wave oscillator 115a, and may delay the drive signal input from the first drive signal amplifier 222a and output it to the first acoustic wave oscillator 115a.

[0128] In the medium conveying device according to this embodiment, a drive signal delay circuit is provided between the drive signal generator 121 and the first or second sound wave transmitter, so that the output device 123 outputs the first and second sound wave signals to the processing circuit 150 at different timings. This reduces the influence of manufacturing errors in the placement position of the sound wave sensor, and allows the medium conveying device to reliably and accurately set the time difference between the first and second sound wave signals. In addition, in the medium conveying device, the distance between the sound wave transmitter and sound wave receiver in each sound wave sensor is the same, which makes it easier to design and implement.

[0129] Also in this embodiment, instead of the sonic signal amplifier 124, a first sonic signal amplifier 324a and a second sonic signal amplifier 324b may be used.

[0130] As described above in detail, the medium conveying device is able to appropriately determine the state of the medium while suppressing increases in device costs, even when the drive signal is delayed by the drive signal delay circuit.

[0131] FIG. 12 is a schematic diagram for explaining a sound wave signal delay circuit 526 in a medium conveying device according to yet another embodiment.

[0132] The medium conveying device according to this embodiment has the same components as the medium conveying device 100. However, as shown in FIG. 12, the medium conveying device according to this embodiment has a second sonic sensor 416 instead of the second sonic sensor 116, and further has a sonic signal delay circuit 526.

[0133] The sonic signal delay circuit 526 is an example of a signal delay circuit. The sonic signal delay circuit 526 is a delay circuit including a capacitor, a resistor, and the like, and is disposed between the second sonic receiver 416b and the output device 123. The second sonic receiver 416b outputs a second sonic signal to the sonic signal delay circuit 526. The sonic signal delay circuit 526 delays the sonic signal input from the second sonic receiver 416b by a predetermined time and outputs the delayed signal to the output device 123. The predetermined time is set to, for example, 10 μsec.

[0134] In addition, the sonic signal delay circuit may be disposed between the first sonic receiver 115b and the output device 123, and may delay the drive signal input from the first sonic receiver 115b and output it to the output device 123. As shown in FIG. 10, when the first sonic signal amplifier 324a and the second sonic signal amplifier 324b are provided, the sonic signal delay circuit may be disposed between the second sonic receiver 416b and the second sonic signal amplifier 324b, and may delay the sonic signal input from the second sonic receiver 416b and output it to the second sonic signal amplifier 324b. Alternatively, the sonic signal delay circuit may be disposed between the second sonic signal amplifier 324b and the output device 123, and may delay the sonic signal input from the second sonic signal amplifier 324b and output it to the output device 123. Alternatively, the sonic signal delay circuit may be disposed between the first sonic receiver 115b and the first sonic signal amplifier 324a, and may delay the sonic signal input from the first sonic receiver 115b and output it to the first sonic signal amplifier 324a. Alternatively, the sonic signal delay circuit may be disposed between the first sonic signal amplifier 324a and the output device 123, and may delay the sonic signal input from the first sonic signal amplifier 324a and output it to the output device 123.

[0135] In this way, in the medium conveying device according to this embodiment, a sound signal delay circuit is provided between the first or second sound receiver and the output device, so that the output device 123 outputs the first sound signal and the second sound signal to the processing circuit 150 at different timings. This allows the medium conveying device to reduce the effects of manufacturing errors in the placement position of the sound sensor, and to reliably and accurately set the time difference between the first sound signal and the second sound signal. In addition, in the medium conveying device, the distance between the sound transmitter and the sound receiver in each sound sensor is the same, which makes it easier to design and implement.

[0136] In this embodiment, instead of the drive signal amplifier 122, a first drive signal amplifier 222a and a second drive signal amplifier 222b may be used.

[0137] As described above in detail, the medium transport device is able to appropriately determine the state of the medium while suppressing increases in device costs, even when the sound signal is delayed by the sound signal delay circuit.

[0138] FIG. 13 is a diagram showing a schematic configuration of a processing circuit 650 of a medium conveying device according to another embodiment.

[0139] The processing circuit 650 is used in place of the processing circuit 150, and executes media reading processing and the like in place of the processing circuit 150. The processing circuit 650 has a control circuit 651, a determination circuit 652, and the like. Note that each of these units may be composed of an independent integrated circuit, microprocessor, firmware, and the like.

[0140] The control circuit 651 is an example of a control unit, and has the same functions as the control unit 151. The control circuit 651 receives an operation signal from the operation device 105 or the interface device 132, a medium signal from the medium sensor 111, and a determination result of the state of the medium from the determination circuit 652, and controls the motor 131 to transport the medium based on each piece of received information. The control circuit 651 obtains an input image from the imaging device 119, and outputs it to the interface device 132. The control circuit 651 also controls the drive signal generator 121 to output a drive signal.

[0141] The determination circuit 652 is an example of a determination unit, and has the same function as the determination unit 152. The determination circuit 652 receives the first and second sound wave signals from the A / D converter 125, determines the state of the medium based on the received first and second sound wave signals, and outputs the determination result to the control circuit 651.

[0142] As described above in detail, even when the processing circuit 650 is used, the medium conveying device is able to appropriately determine the state of the medium while suppressing increases in device costs.

[0143] Although preferred embodiments have been described above, the embodiments are not limited to these. For example, the number of sonic sensors is not limited to two, and may be any number of three or more. In this case, the sonic sensors are disposed at any positions different from each other. The sonic sensors are disposed such that the distances between the sonic transmitter and the sonic receiver of each sonic sensor are different from each other. Alternatively, a signal delay circuit is provided between the drive signal generator 121 and each sonic transmitter, or between each sonic receiver and the output device 123. As a result, the output device 123 is provided so as to output the sonic signals output from the sonic receivers of each sonic sensor at different timings. The determination unit 152 determines the state of the medium based on the sonic signals output from each sonic sensor.

[0144] The medium transport device may also have a so-called straight path, and feed and transport the medium placed on the loading table from the bottom up, and discharge the medium onto the discharge table. In this case, the separation roller is disposed above the feed roller, facing the feed roller. In this case, too, the medium transport device can appropriately determine the state of the medium while suppressing increases in device costs. [Explanation of symbols]

[0145] 100 medium conveying device, 112 pick roller, 113 feeding roller, 114 separation roller, 117a-h first to eighth conveying rollers, 118a-h first to eighth driven rollers, 115a first sound wave transmitter, 115b first sound wave receiver, 116a, 416a second sound wave transmitter, 116b, 416b second sound wave receiver, 121 drive signal generator, 122 drive signal amplifier, 123 output device, 124 sound wave signal amplifier, 152 determination unit, 222a first drive signal amplifier, 222b second drive signal amplifier, 324a first sound wave signal amplifier, 324b second sound wave signal amplifier, 426 drive signal delay circuit, 526 sound wave signal delay circuit

Claims

1. A medium transport device that transports a medium along a transport path, a first sound wave transmitter and a second sound wave transmitter that output sound waves including audible sounds or ultrasonic waves; a first sonic wave receiver disposed opposite the first sonic wave transmitter across the transport path and configured to output a first sonic wave signal in response to the received sonic wave; a second sonic wave receiver disposed opposite the second sonic wave transmitter across the transport path and configured to output a second sonic wave signal in response to the received sonic wave; a determination unit that determines the state of the medium based on the first sound wave signal and the second sound wave signal, the distance between the first acoustic wave transmitter and the first acoustic wave receiver is different from the distance between the second acoustic wave transmitter and the second acoustic wave receiver; A medium transport device characterized by:

2. A medium conveying device as described in claim 1, further having an output unit that outputs the first sonic signal and the second sonic signal to the judgment unit at mutually different timings.

3. The device further includes a drive signal output unit that outputs drive signals at predetermined timings to cause the first sound wave transmitter and the second sound wave transmitter to output the sound waves; A medium conveying device as described in claim 2, wherein a signal delay circuit is provided between the drive signal output unit and the first acoustic wave transmitter or the second acoustic wave transmitter, or between the first acoustic wave receiver or the second acoustic wave receiver and the output unit, so that the output unit outputs the first acoustic wave signal and the second acoustic wave signal to the determination unit at mutually different timings.

4. The medium conveying device according to claim 3 , further comprising an amplifier that amplifies the drive signal output from the drive signal output section and outputs the amplified signal to the first sound wave oscillator and the second sound wave oscillator.

5. a first amplifier that amplifies the drive signal output from the drive signal output unit and outputs the amplified drive signal to the first acoustic wave oscillator; The medium conveying device according to claim 3 , further comprising: a second amplifier that amplifies the drive signal output from the drive signal output section and outputs the amplified signal to the second sound wave oscillator.

6. The medium conveying device according to claim 2 , further comprising an amplifier that amplifies the first sound wave signal and the second sound wave signal output from the output unit and outputs the amplified signal to the determination unit.

7. a first amplifier that amplifies the first sound wave signal output from the first sound wave receiver and outputs the amplified first sound wave signal to the output unit; The medium conveying device according to claim 2 , further comprising: a second amplifier that amplifies the second sound wave signal output from the second sound wave receiver and outputs the amplified second sound wave signal to the output section.

8. A first sound wave transmitter and a second sound wave transmitter output sound waves including audible sounds or ultrasonic waves, a first sonic wave receiver disposed opposite the first sonic wave transmitter across a transport path along which the medium is transported outputs a first sonic wave signal corresponding to the received sonic wave; a second sonic wave receiver disposed opposite the second sonic wave transmitter across the conveyance path outputs a second sonic wave signal corresponding to the received sonic wave; determining a state of the medium based on the first acoustic signal and the second acoustic signal; the distance between the first acoustic wave transmitter and the first acoustic wave receiver is different from the distance between the second acoustic wave transmitter and the second acoustic wave receiver; A determination method characterized by:

9. A control program for a media transport device that transports a medium along a transport path, the control program comprising: a first sound wave transmitter and a second sound wave transmitter that output sound waves including audible sounds or ultrasonic waves; a first sound wave receiver that is disposed opposite the first sound wave transmitter across the transport path and that outputs a first sound wave signal in response to the received sound waves; and a second sound wave receiver that is disposed opposite the second sound wave transmitter across the transport path and that outputs a second sound wave signal in response to the received sound waves, determining a state of the medium based on the first and second acoustic signals; the distance between the first acoustic wave transmitter and the first acoustic wave receiver is different from the distance between the second acoustic wave transmitter and the second acoustic wave receiver; A control program comprising:

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