JP2012096851A - Sheet conveying device and image reading device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device which can specify a failure occurring spot in conveyance of a sheet with simple constitution, and an image reading device including the sheet conveying device.SOLUTION: A transmitting side opening 103C and a transmitting side opening 103B, and a receiving side opening 104C and a receiving side opening 104B are arranged across a second separation roller 34 and a second separation piece 35 in an X-axis direction. The transmitting side opening 103B and a transmitting side opening 103A, and the receiving side opening 104B and a receiving side opening 104A are arranged across a conveying roller 36 and a driven roller for conveyance 37 in the X-axis direction. Whether or not the failure occurs in the conveyance of the sheet is determined based on time when an ultrasonic wave is received by an ultrasonic wave receiving part 106 through the receiving side openings 104A to 104C and an amplitude value of the ultrasonic wave received by the ultrasonic wave receiving part 106. When determining that the failure occurs in the conveyance of the sheet, the failure occurring spot is specified.

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet, and an image reading apparatus including the sheet conveying apparatus.

  2. Description of the Related Art Conventionally, there has been proposed a sheet conveying apparatus that determines whether or not an abnormality such as a jam has occurred in conveying a conveyed sheet while conveying the sheet. As an example, the sheet conveying apparatuses disclosed in Patent Documents 1 and 2 include a plurality of sensors along the conveying path, and specify in which part of the conveying path an abnormality has occurred.

JP-A-9-290550 JP-A-7-301963

  However, the sheet conveying apparatus disclosed in Patent Document 1 needs to provide a plurality of sensors, that is, a plurality of ultrasonic transmission units and a plurality of ultrasonic reception units, along the conveyance path. Therefore, the configuration for specifying an abnormality occurrence location is complicated.

  The present invention has been made in order to solve the above-described problems, and has a sheet conveyance device that can identify an abnormal position of sheet conveyance with a simple configuration, and an image reading apparatus including the sheet conveyance device. The purpose is to provide.

  In order to achieve the above object, the present invention according to claim 1 is a sheet conveying apparatus for conveying a sheet, wherein an ultrasonic wave generating unit that generates pulsed ultrasonic waves, and the conveying direction of the sheet The ultrasonic waves generated by the ultrasonic wave generation unit are arranged at different positions, connected to the plurality of transmission side openings for transmitting the ultrasonic waves, the ultrasonic wave generation unit, and the plurality of transmission side openings. A transmission-side transmission unit that transmits sound waves to the plurality of transmission-side openings, and a plurality of transmission-side openings that are arranged at positions different from each other with respect to the sheet conveyance direction. A plurality of reception side openings for receiving the ultrasonic waves transmitted by the transmission side openings, a plurality of reception units for receiving the ultrasonic waves received by the plurality of reception side openings, and a plurality of the receptions Side opening and the super sound A receiving side transmission unit coupled to a receiving unit and transmitting the ultrasonic waves received by the plurality of receiving side openings to the ultrasonic receiving unit; and the ultrasonic receiving units via the plurality of receiving side openings. A determination unit that determines whether or not an abnormality has occurred in the conveyance of the sheet based on a time when the ultrasonic wave is received by the unit and an amplitude value of the ultrasonic wave received by the ultrasonic wave reception unit; The path length of the plurality of paths from the ultrasonic wave generation unit to the ultrasonic wave reception unit through the transmission side transmission unit, the plurality of transmission side openings, and the plurality of reception side openings is , Which are of different lengths.

  According to a second aspect of the present invention, in the first aspect of the invention, the plurality of transmission side openings are provided in the invention according to the first aspect, wherein the plurality of transmission portions are arranged along the conveyance direction of the sheet and act on the sheet. Are arranged with the plurality of action portions sandwiched in the sheet conveyance direction, and the plurality of reception side openings are arranged with the plurality of action portions sandwiched in the sheet conveyance direction. Is.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, at least three of the transmission side openings are provided, and at least three of the transmission side openings are provided. Among them, the distance between two transmission side openings adjacent to each other in the transmission side transmission part, and two reception sides adjacent to each other in the reception side transmission part among at least three reception side openings The distance between the openings is a distance equal to or more than half the value obtained by multiplying the reverberation time and the sound speed depending on the configuration of the transmission-side transmission unit and the reception-side transmission unit, respectively. It is characterized by being.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the transmission-side transmission unit and the reception-side transmission unit include a bent portion. is there.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the transmission-side transmission unit, the plurality of transmission-side openings, the reception-side transmission unit, and the plurality of the transmission units Each of the reception side openings is constituted by a voice tube.

  A sixth aspect of the present invention is the invention according to any one of the first to fifth aspects, further comprising a notifying unit for notifying occurrence of abnormality based on a determination result of the determining unit. It is.

  The present invention according to claim 7 is an image reading apparatus, wherein the sheet conveying apparatus according to any one of claims 1 to 6, and a reading unit that reads an image of the sheet conveyed by the sheet conveying apparatus, It is characterized by providing.

  According to the sheet conveying apparatus of the first aspect, the ultrasonic wave generation unit and the plurality of transmission side openings are connected by the transmission side transmission unit. Further, the ultrasonic wave receiving unit and the plurality of reception side openings are connected by the reception side wave transmission unit. Therefore, only by generating an ultrasonic wave from one ultrasonic wave generation unit, the ultrasonic wave is transmitted through the transmission side transmission unit and transmitted from a plurality of transmission side openings. The ultrasonic waves received by the plurality of reception side openings are transmitted through the reception side transmission unit and received by one ultrasonic reception unit. Therefore, it is not necessary to transmit ultrasonic waves separately from the plurality of ultrasonic transmission units, and it is not necessary to receive ultrasonic waves separately from the plurality of ultrasonic reception units. Therefore, it is possible to identify the location where the sheet conveyance abnormality has occurred with a simple configuration.

  According to the sheet conveying apparatus according to claim 2, since the plurality of transmission side openings and the plurality of reception side openings are arranged with the plurality of action parts sandwiched in the sheet conveyance direction, the action part determines the sheet. It is possible to specify whether or not a conveyance abnormality has occurred. Note that the action unit includes a conveyance unit that conveys a sheet, a separation unit that conveys the sheet while separating the sheet, and an image forming unit that forms an image by discharging ink or the like onto the sheet.

  According to the sheet conveying apparatus according to claim 3, the reverberation generated in the reception-side transmission unit when the ultrasonic wave is received by the specific reception-side opening among the plurality of reception-side openings is the specific reception. After the side opening receives the ultrasonic wave, it does not remain in the reception-side transmission unit until the ultrasonic wave is received by the opening adjacent to the specific reception side opening. If reverberation remains until an ultrasonic wave is received by the adjacent reception side opening, the ultrasonic wave received by the adjacent reception side opening and the reverberation are superimposed. If the ultrasonic wave and the reverberation are superposed in this way, the accuracy of specifying the abnormality occurrence location is affected. Therefore, according to the sheet conveying apparatus of the third aspect, it is possible to prevent the reverberation from affecting the accuracy of specifying the abnormality occurrence location.

  According to the sheet conveying apparatus of the fourth aspect, it is possible to increase the distance in the conveying direction by bending the ultrasonic path in the transmitting side transmitting unit and the receiving side transmitting unit. Therefore, in order to avoid the influence of reverberation, it is not necessary to increase the distance in the conveyance direction between the plurality of transmission side openings and the plurality of reception side openings. Accordingly, it is possible to specify the location where the sheet conveyance abnormality has occurred with a simple configuration while reducing the size of the apparatus in the conveyance direction.

  According to the sheet conveying apparatus of the fifth aspect, the transmission-side transmission unit, the plurality of transmission-side openings, the reception-side transmission unit, and the plurality of reception-side openings are each configured by a voice tube. Therefore, the number of parts is reduced for the transmission side transmission unit, the plurality of transmission side openings, the reception side transmission unit, and the plurality of reception side openings, respectively, as compared with the case where separate components are used. be able to.

  According to the sheet conveying apparatus of the sixth aspect, it is possible to notify the user of whether or not a sheet abnormality has occurred. Therefore, it can be notified to the user whether or not the user is reliably transported without any abnormality.

  According to the image reading apparatus of the seventh aspect, the ultrasonic wave generation unit and the plurality of transmission side openings are connected by the transmission side transmission unit. Further, the ultrasonic wave receiving unit and the plurality of reception side openings are connected by the reception side wave transmission unit. Therefore, only by generating an ultrasonic wave from one ultrasonic wave generation unit, the ultrasonic wave is transmitted through the transmission side transmission unit and transmitted from a plurality of transmission side openings. The ultrasonic waves received by the plurality of reception side openings are transmitted through the reception side transmission unit and received by one ultrasonic reception unit. Therefore, it is not necessary to transmit ultrasonic waves separately from the plurality of ultrasonic transmission units, and it is not necessary to receive ultrasonic waves separately from the plurality of ultrasonic reception units. Therefore, it is possible to identify the location where the sheet conveyance abnormality has occurred with a simple configuration.

1 is a perspective view showing an image reading apparatus 1 according to first and second embodiments of the present invention. FIG. 2 is an explanatory diagram for explaining an internal configuration of the image reading apparatus 1. FIG. 3 is a side view showing a detection unit 10 of the image reading apparatus 1. It is a front view which shows the said detection part. It is explanatory drawing for demonstrating generation | occurrence | production, transmission, and reception of the ultrasonic wave by the said detection part. It is explanatory drawing for demonstrating the influence on the detection accuracy of a sheet | seat by superimposition of an ultrasonic wave and reverberation. 2 is a block diagram showing an electrical configuration of the image reading apparatus 1. FIG. 3 is a flowchart illustrating control of the image reading apparatus 1 according to the first embodiment of the present invention. It is explanatory drawing for demonstrating the jam detection by the said detection part. 6 is a flowchart illustrating control of the image reading apparatus 1 according to a second embodiment of the present invention. It is a top view which shows 200 A of ultrasonic transmission parts which concern on the modification of this invention. It is a top view which shows the ultrasonic transmission part 300A which concerns on one modification of this invention.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[Appearance of image reader]
FIG. 1 is a perspective view showing an appearance of the image reading apparatus 1 of the present embodiment. As illustrated in FIG. 1, the image reading apparatus 1 includes a paper feed tray 2, a reading unit 3, a paper discharge tray 4, a setting unit 5, and a display unit 6. The image reading apparatus 1 according to the present embodiment is a sheet feed scanner that reads a plurality of sheets SH placed on a paper feed tray 2 by a user while being conveyed in a reading unit 3.

  The reading unit 3 pulls the sheet SH placed on the paper feed tray 2 into the reading unit 3. The reading unit 3 conveys the pulled sheet SH from the paper feed tray 2 toward the paper discharge tray 4 inside the reading unit 3. The reading unit 3 reads an image of the conveyed sheet SH inside the reading unit 3.

  The paper discharge tray 4 receives the sheet SH conveyed by the reading unit 3. The setting unit 5 has a power switch and various setting buttons. The display unit 6 is configured by a liquid crystal display. The display unit 6 can display an image read by the reading unit 3. For example, the display unit 6 can display a message “abnormality occurrence” indicating that an abnormality has occurred in the conveyance of the sheet SH.

[Internal structure of image reading apparatus]
FIG. 2 is an explanatory diagram for explaining the internal structure of the image reading apparatus 1. As shown in FIG. 2, the image reading apparatus 1 includes a detection unit 10, a reading sensor 31, a first separation roller 32, a first separation piece 33, and a second separation roller 34 inside the reading unit 3. The second separation piece 35, the conveyance roller 36, the conveyance driven roller 37, the discharge roller 38, the discharge driven roller 39, and the control unit 7. The sheet SH is transported in a transport path FP formed between the upper part and the lower part of the image reading apparatus 1.

  The first separation roller 32 pulls the plurality of sheets SH placed on the paper feed tray 2 into the image reading apparatus 1 by frictional force. The first separation roller 32 is driven by a motor (not shown). The first separation piece 33 separates the plurality of sheets SH by a frictional force. It is desirable that the plurality of sheets SH be separated into one sheet SH by the first separation piece 33, but even in the presence of the first separation piece 33, the plurality of sheets SH can be separated into one sheet SH. It may not be separated. The second separation piece 35 is configured so that the sheet SH can be separated into one sheet SH as much as possible when the plurality of sheets SH are not separated into one sheet SH by the first separation piece 33. The separation piece 33 is provided on the downstream side in the conveyance direction.

  The second separation roller 34 is driven by a motor (not shown) and conveys the sheet SH. The second separation piece 35 is disposed to face the second separation roller 34. The second separation roller 34 and the second separation piece 35 sandwich the sheet SH between the second separation roller 34 and the second separation piece 35. The sheet SH is conveyed in the conveyance path FP by the frictional force between the second separation roller 34 and the second separation piece 35.

  The detection unit 10 detects the conveyed sheet SH. The detection unit 10 is configured by an ultrasonic sensor. The detection unit 10 includes an ultrasonic transmission unit 10A and an ultrasonic reception unit 10B. The ultrasonic transmission unit 10A transmits pulsed ultrasonic waves to the conveyed sheet SH. The ultrasonic receiver 10B receives the ultrasonic waves transmitted by the ultrasonic transmitter 10A. When the sheet SH passes between the ultrasonic transmission unit 10A and the ultrasonic reception unit 10B, the ultrasonic wave transmitted through the sheet SH and reaching the ultrasonic reception unit 10B is received by the ultrasonic reception unit 10B. . Although not shown in detail in FIG. 2, the conveyance path FP includes a hole that allows passage of ultrasonic waves from the ultrasonic transmission unit 10A to the ultrasonic reception unit 10B.

  Thereafter, as shown in FIG. 2, the sheet SH is conveyed in the X-axis direction, on a plane parallel to the surface of the sheet SH being conveyed, and in the Y-axis direction perpendicular to the X-axis direction. A direction perpendicular to the surface of the sheet SH is defined as the Z-axis direction. Therefore, for example, a plane parallel to the surface of the sheet SH conveyed between the ultrasonic transmission unit 10A and the ultrasonic reception unit 10B is parallel to the XY plane. In the following, “upper” or “front” means the positive direction of the Z-axis indicated by the arrow shown in FIG. 2, and “lower” or “back” shows the same in FIG. It shall mean the negative direction of the Z axis. The definitions of the X-axis direction, the Y-axis direction, and the Z-axis direction are common to other drawings. Strictly speaking, the transport path FP is curved, and the transport direction of the sheet SH transported in the transport path FP changes according to the arrival point of the sheet SH in the transport path FP. However, for clarification of the explanation, in FIG. 2 and other drawings, an example is described as the X-axis direction, and in the following description, an example is described as the X-axis direction. The same applies to the Y-axis direction and the Z-axis direction.

  The conveyance roller 36 is driven by a motor (not shown) to convey the sheet SH. As shown in FIG. 2, the conveyance roller 36 is disposed between the ultrasonic transmission unit 10A and the ultrasonic reception unit 10B. The transport driven roller 37 is disposed to face the transport roller 36. The conveyance roller 36 and the conveyance driven roller 37 sandwich the sheet SH between the conveyance roller 36 and the conveyance driven roller 37. The sheet SH is transported in the transport path FP by the frictional force between the transport roller 36 and the transport driven roller 37.

  The reading sensor 31 includes a pair of contact image sensors (Contact Image Sensor, hereinafter referred to as “CIS”) 31A and 31B that are opposed to each other with the conveyance path FP interposed therebetween. The CISs 31A and 31B are line type image sensors in which a plurality of light receiving elements are arranged in the Y-axis direction. The reading sensor 31 reads images on the front surface and the back surface of the sheet SH.

  The discharge roller 38 is disposed on the downstream side of the reading sensor 31 in the transport path FP. The discharge driven roller 39 is disposed to face the discharge roller 38. The discharge roller 38 and the discharge driven roller 39 sandwich the sheet SH between the discharge roller 38 and the discharge driven roller 39. The sheet SH is conveyed in the conveyance path FP by the frictional force between the discharge roller 38 and the discharge driven roller 39. The discharge roller 38 sends the sheet SH conveyed in the conveyance path FP to the sheet discharge tray 4 shown in FIG. The discharge roller 38 is driven by a motor (not shown). The sheet SH is discharged to the discharge tray 4 shown in FIG.

  The control unit 7 is configured by a computer having a CPU, ROM, RAM, flash ROM, and the like.

[Appearance of detector]
FIG. 3 is a front view showing the appearance of the detection unit 10 (a view seen from the positive direction of the Y axis). FIG. 4 is a side view showing the appearance of the detection unit 10 (viewed from the positive direction of the X axis). In FIG. 4, the sheet SH is shown together with the detection unit 10.

  As shown in FIGS. 3 and 4, the detection unit 10 includes an ultrasonic transmission unit 10 </ b> A and an ultrasonic reception unit 10 </ b> B. As illustrated in FIG. 3, the ultrasonic transmission unit 10A includes an ultrasonic wave generation unit 101, a transmission-side transmission unit 102, and transmission-side openings 103A, 103B, and 103C. As illustrated in FIG. 3, the ultrasonic receiving unit 10 </ b> B includes reception-side openings 104 </ b> A, 104 </ b> B, and 104 </ b> C, a reception-side transmission unit 105, and an ultrasonic reception unit 106.

  The ultrasonic wave generation unit 101 generates pulsed ultrasonic waves. The transmission-side transmission unit 102 is connected to the ultrasonic wave generation unit 101 and the transmission-side openings 103A, 103B, and 103C. The transmission-side transmission unit 102 transmits the ultrasonic waves generated by the ultrasonic generation unit 101 to the transmission-side openings 103A, 103B, and 103C. As shown in FIG. 3, the transmission-side transmission unit 102 extends in the X-axis direction. Therefore, the transmission-side transmission unit 102 can transmit the ultrasonic wave generated by the ultrasonic wave generation unit 101 in the X-axis direction.

  The transmission side openings 103A, 103B, 103C are arranged at different positions in the X-axis direction as shown in FIG. That is, the transmission side openings 103A, 103B, and 103C are arranged at different coordinate positions in the X-axis direction. The transmission side openings 103A, 103B, and 103C are arranged at the same position with respect to the Y-axis direction. That is, the transmission side openings 103A, 103B, and 103C are arranged at the same coordinate position in the Y-axis direction. As shown in FIG. 3, each of the transmission side openings 103A, 103B, and 103C is arranged with the opening portion directed toward the Z-axis negative direction. In FIG. 3, the sheet SH is conveyed in the positive direction of the X axis between the ultrasonic transmitter 10 </ b> A and the ultrasonic receiver 10 </ b> B with the surface parallel to the XY plane. The transmission-side transmission unit 102 and the transmission-side openings 103A, 103B, 103C are configured by a hollow transmission tube made of a hard plastic material.

  In the present embodiment, the first distance L1 from the ultrasonic wave generation unit 101 to the transmission-side opening 103A and the second distance L2 from the ultrasonic wave generation unit 101 to the transmission-side opening 103C in the X-axis direction are respectively the first. The distance L1 = 40 mm and the second distance L2 = 50 mm. Therefore, the first distance L1 <the second distance L2. That is, the first distance L1 and the second distance L2 are different distances.

  As shown in FIG. 2, the transmission-side opening 103C and the transmission-side opening 103B are arranged with the second separation roller 34 and the second separation piece 35 interposed therebetween in the X-axis direction. The transmission side opening 103B and the transmission side opening 103A are arranged with the conveyance roller 36 and the conveyance driven roller 37 in between in the X-axis direction.

  The reception side openings 104A, 104B, and 104C receive the ultrasonic waves transmitted through the transmission side openings 103A, 103B, and 103C, respectively. When the sheet SH is conveyed between the transmission side openings 103A, 103B, and 103C and the reception side openings 104A, 104B, and 104C, the reception side openings 104A, 104B, and 104C are respectively transmitted to the transmission side openings 103A, The ultrasonic waves that have reached the receiving-side openings 104A, 104B, and 104C are received via the 103B and 103C and the sheet SH. As shown in FIG. 3, the reception side openings 104A, 104B, and 104C are arranged at different positions with respect to the X-axis direction. That is, the receiving side openings 104A, 104B, and 104C are arranged at different coordinate positions in the X-axis direction. The reception side openings 104A, 104B, 104C are arranged at the same position with respect to the Y-axis direction. That is, the receiving side openings 104A, 104B, and 104C are arranged at the same coordinate position in the Y-axis direction. As shown in FIG. 3, each of the reception side openings 104A, 104B, and 104C is disposed with the opening portion directed toward the Z axis positive direction.

  The reception side openings 104A, 104B, and 104C are located at the same positions as the transmission side openings 104A, 104B, and 104C, respectively, with respect to the X-axis direction. Therefore, the distance from the ultrasonic wave receiving unit 106 to the reception side opening 104A in the X-axis direction is equal to the first distance L1. The distance from the ultrasonic wave receiving unit 106 to the reception side opening 104C in the X-axis direction is equal to the second distance L2. Therefore, the distance from the ultrasonic receiving unit 106 to the receiving side opening 104A in the X-axis direction is different from the distance from the ultrasonic receiving unit 106 to the receiving side opening 104C.

  As shown in FIG. 2, the reception side opening 104 </ b> C and the reception side opening 104 </ b> B are arranged with the second separation roller 34 and the second separation piece 35 interposed therebetween in the X-axis direction. The reception side opening 104B and the reception side opening 104A are arranged with the conveyance roller 36 and the conveyance driven roller 37 in between in the X-axis direction.

  The reception-side transmission unit 105 is connected to the reception-side openings 104A, 104B, 104C and the ultrasonic reception unit 106. As shown in FIG. 3, the reception-side transmission unit 105 extends in the X-axis direction. Therefore, the reception-side transmission unit 105 can transmit the ultrasonic waves received by the reception-side openings 104A, 104B, and 104C in the X-axis direction. The reception-side transmission unit 105 transmits the ultrasonic waves received by the reception-side openings 104A, 104B, and 104C to the ultrasonic reception unit 106. The ultrasonic receiving unit 106 receives the ultrasonic waves received by the reception side openings 104A, 104B, and 104C. The reception-side transmission unit 105 and the reception-side openings 104A, 104B, and 104C are configured by a hollow transmission tube made of a hard plastic material.

  As shown in FIG. 3, the transmission side opening 103B, the reception side opening 104B, the ultrasonic wave generation unit 101, and the ultrasonic wave reception unit 106 are arranged at the same position in the X-axis direction.

  As shown in FIG. 4, the ultrasonic transmission unit 10A and the ultrasonic reception unit 10B are configured such that the sheet SH is between the transmission side openings 103A, 103B, and 103C and the reception side openings 104A, 104B, and 104C in the X-axis direction. Are opposed to each other in the Z-axis direction with the sheet SH interposed therebetween. The ultrasonic transmitter 10A and the ultrasonic receiver 10B are arranged at the same position with respect to the X-axis direction.

  As described above, the first distance L1 from the ultrasonic wave generation unit 101 to the transmission side opening 103A and the second distance L2 from the ultrasonic wave generation unit 101 to the transmission side opening 103C in the X-axis direction are different distances. is there. Further, the first distance L1 from the ultrasonic wave receiving unit 106 to the reception side opening 104A and the second distance L2 from the ultrasonic wave reception unit 106 to the reception side opening 104C in the X-axis direction are different distances. Therefore, the path length from the ultrasonic wave generation unit 101 to the ultrasonic wave reception unit 106 via the transmission side transmission unit 102, the transmission side opening 103A, and the reception side opening 104A, and the ultrasonic wave generation unit 101 The path length from the ultrasonic wave generation unit 101 to the transmission side transmission unit 102 through the transmission side transmission unit 102, the transmission side opening 103B, and the reception side opening 104B to the ultrasonic reception unit 106. The path length of the path from the transmission side opening 103C and the reception side opening 104C to the ultrasonic wave reception unit 106 is a different length.

  The ultrasonic wave passing through the transmission-side opening 103C is attenuated when the sheet SH exists at the specific location AC shown in FIG. 2 and passes through the sheet SH at that time. The ultrasonic wave passing through the transmission side opening 103B is attenuated when the sheet SH exists at the specific location AB and passes through the sheet SH at that time. The ultrasonic wave passing through the transmission side opening 103A is attenuated when the sheet SH exists at the specific location AA and passes through the sheet SH at that time. Therefore, by detecting the ultrasonic wave via the transmission side openings 103A, 103B, and 103C, it is possible to specify in which part of the transport path FP the sheet SH is present. Further, by detecting the ultrasonic waves via the transmission side openings 103A, 103B, 103C and detecting the standby time of the sheet SH at the specific locations AA, AB, AC, the sheet SH is out of the specific locations AA, AB, AC. If it is determined in any of the cases that it has been waiting for a predetermined time or more, it can be determined that a jam has occurred at the specific location.

  In addition, the frequency with which an ultrasonic wave is generated per unit time by the ultrasonic wave generation unit 101 is very high. Therefore, when the sheet SH is conveyed under the transmission side opening 103C, under the transmission side opening 103B, and under the transmission side opening 103A, the transmission side opening 103C and the transmission side opening are always provided to the sheet SH at least once. The ultrasonic waves transmitted through the part 103B and the transmission side opening 103A are transmitted.

  With reference to FIG. 5, transmission / reception of ultrasonic waves by the above-described detection unit 10 will be described. In FIG. 5A, the horizontal axis indicates a time TM during which ultrasonic waves are generated by the ultrasonic wave generation unit 101. In FIG. 5A, the vertical axis indicates the amplitude AM of the ultrasonic wave generated by the ultrasonic wave generation unit 101. In FIG. 5B, the horizontal axis is a diagram showing the time TM during which ultrasonic waves are transmitted from the transmission side openings 103A, 103B, 103C. In FIG. 5B, the vertical axis indicates the amplitude AM of the ultrasonic wave transmitted from the transmission side openings 103A, 103B, 103C. In FIG. 5C, the horizontal axis indicates the time TM when the ultrasonic wave is received by the ultrasonic wave receiving unit 106. In FIG. 5C, the vertical axis represents the amplitude AM of the ultrasonic wave received by the ultrasonic wave receiving unit 106. However, (C) in FIG. 5 illustrates that when the sheet SH is not interposed between the transmission side openings 103A, 103B, and 103C and the reception side openings 104A, 104B, and 104C, ultrasonic waves are transmitted from the transmission side openings 103A, The amplitude AM of the ultrasonic wave received by the ultrasonic wave receiving unit 106 when transmitted from the 103B and 103C to the reception side openings 104A, 104B and 104C is shown. In FIGS. 5A, 5B, and 5C, the time TM is indicated by a common time axis, and the amplitude AM is indicated by a common unit. Therefore, for example, the time point TG1 shown in FIG. 5A and the time point TG1 shown in FIGS. 5B and 5C are the same time TM.

  As shown in FIG. 5A, the pulsed ultrasonic waves generated by the ultrasonic generator 101 at times TG1 to TG2 are first superposed at times TT1 to TT2 as shown in FIG. It is transmitted from the transmission side opening 103B located on the Z-axis negative direction side of the sound wave generation unit 101. Hereinafter, for example, the time from the time TG1 to the time TG2 is expressed as “time TG1 to TG2”. The ultrasonic wave travels through the transmission-side transmission unit 102. Since the first distance L1 <the second distance L2, the ultrasonic wave transmitted through the transmission side transmission unit 102 is transmitted from the transmission side opening 103A at time TT3 to TT4 as shown in FIG. 5B. The Thereafter, the ultrasonic wave is transmitted from the transmission-side opening 103C at times TT5 to TT6. As described above, the distance from the ultrasonic wave generation unit 101 to the transmission side openings 103A, 103B, and 103C in the transmission side transmission unit 102 is different, so that the transmission side opening is not required without controlling the transmission timing of the ultrasonic waves. The timing at which ultrasonic waves are transmitted from the units 103A, 103B, and 103C can be shifted. The pulse width of the pulsed ultrasonic wave generated by the ultrasonic wave generation unit 101 is such that the ultrasonic waves transmitted from the transmission side openings 103A, 103B, and 103C do not overlap as shown in FIG. Is preset. The set value of the pulse width is a value determined by the first distance L1 and the second distance L2.

  The ultrasonic waves transmitted from the transmission side opening 103B at time TT1 to TT2 are received by the reception side opening 104B. The ultrasonic wave WB received by the reception side opening 104B is received by the ultrasonic wave receiving unit 106 at times TR1 and TR2, as shown in FIG. The ultrasonic waves transmitted from the transmission side opening 103A at the times TT3 to TT4 shown in FIG. 5B are received by the reception side opening 104A. The ultrasonic wave WA received by the reception side opening 104A travels through the reception side transmission unit 105 and is received by the ultrasonic reception unit 106 at times TR3 to TR4. The ultrasonic waves transmitted from the transmission side opening 103C at the times TT5 to TT6 are received by the reception side opening 104C. The ultrasonic wave WC received by the reception side opening 104C is transmitted through the reception side transmission unit 105 and is received by the ultrasonic reception unit 106 at times TR5 to TR6. As described above, since the distance from the ultrasonic wave receiving unit 106 to each of the reception side openings 104A, 104B, and 104C in the reception side transmission unit 105 is different, the transmission side opening is not required without controlling the transmission timing of ultrasonic waves. The timing at which each ultrasonic wave received by the units 104A, 104B, and 104C is received by the ultrasonic wave receiving unit 106 can be shifted. That is, the ultrasonic waves received by the reception side openings 104 </ b> A, 104 </ b> B, and 104 </ b> C do not overlap when received by the ultrasonic wave receiving unit 106. Accordingly, it is possible to reliably identify an abnormality occurrence location in the conveyance of the sheet SH.

  The ultrasonic wave generation unit 101 generates an ultrasonic wave next to the ultrasonic wave generated at the time TG1 to TG2 at the time TG3 to TG4. The time interval PR from when the ultrasonic wave is generated at the previous time TG1 to TG2 to when the ultrasonic wave is generated at the later time TG3 to TG4 is as shown in FIGS. 5 (A) and 5 (C). In addition, when the time P1 between the time points TT2 to TT3, the time P2 between the time points TT4 and TT5, and the time PS between the time points TG1 and TG2, the PR> 2 × (3 × PS + P1 + P2) is set in advance. Is set. The preset time interval PR is stored in advance in the ROM included in the control unit 7. Since the time PS is an ultrasonic vibration time, if the frequency of the ultrasonic wave is a frequency FR, PS = (the wave number of the ultrasonic wave generated by one transmission) / FR is satisfied. The time PS + P1, which is the sum of the time PS and the time P1, is from when the ultrasonic wave generated by the ultrasonic wave generation unit 101 is transmitted from the transmission side opening 103B until it is transmitted by the transmission side opening 103A. It's time. Accordingly, the time PS + P1 shown in FIG. 5B satisfies PS + P1 = L1 / SS because the distance from the ultrasonic wave generation unit 101 to the transmission side opening 103A is the distance L1 when the sound speed is the sound speed SS. . Similarly, the time PS + P2 from when the ultrasonic wave generated by the ultrasonic wave generation unit 101 is transmitted by the transmission side opening 103A until it is transmitted by the transmission side opening 103C is from the ultrasonic wave generation unit 101 to the transmission side opening. It is determined by the difference between the distance L1 to the portion 103A and the distance L2 from the ultrasonic wave generator 101 to the transmission side opening 103C. That is, the time PS + P2 shown in FIG. 5B satisfies PS + P2 = (L2−L1) / SS. On the other hand, the time taken for the ultrasonic wave received by the reception side opening 104B to be received by the ultrasonic wave reception unit 106 and the time period until the ultrasonic wave received by the reception side opening 104A is received by the ultrasonic wave reception unit 106. The time difference is PS + P1 (= L1 / SS). In addition, the time taken for the ultrasonic wave received by the reception side opening 104A to be received by the ultrasonic wave reception unit 106 and the time period until the ultrasonic wave received by the reception side opening 104C is received by the ultrasonic wave reception unit 106. The time difference is time PS + P2 = (L2−L1) / SS. Therefore, in FIG. 5C, as shown at times TR1 to TR3, the ultrasonic wave generated from the ultrasonic wave generation unit 101 is transmitted through the transmission side opening 103B and the reception side opening 104B. The signal received by the ultrasonic receiving unit 106 via the transmission side opening 103A and the reception side opening 104A is delayed by 2 × (PS + P1) with respect to the signal received at 106. Further, in FIG. 5C, as shown at times TR1 to TR5, the ultrasonic wave generated from the ultrasonic wave generation unit 101 is transmitted through the transmission side opening 103B and the reception side opening 104B. The signal received through the transmission side opening 103C and the reception side opening 104C is delayed by 2 × (PS + P1) + 2 × (PS + P2) = 2 × (2 × PS + P1 + P2) with respect to the signal received at 106. . Further, in FIG. 5C, as shown at times TR5 to TR6, time PS is required to complete the reception of the signal received through the transmission side opening 103C and the reception side opening 104C. . Therefore, the time interval PR at which the ultrasonic wave is generated by the ultrasonic wave generation unit 101 is set to satisfy PR> 2 × (3 × PS + P1 + P2) as shown in FIG. The ultrasonic wave receiving unit 106 prevents the ultrasonic wave derived from the ultrasonic wave generated at the previous time TG1 to TG2 and the ultrasonic wave derived from the ultrasonic wave generated at the subsequent time TG3 to TG4 from being received in an overlapping manner. be able to. Accordingly, it is possible to reliably identify an abnormality occurrence location in the conveyance of the sheet SH.

  The first distance L1 and the second distance L2 are half the values obtained by multiplying the reverberation time depending on the configurations of the transmission-side transmission unit 102 and the reception-side transmission unit 105 and the sound speed. This is the distance. The reverberation time depends on the configurations of the transmission-side transmission unit 102 and the reception-side transmission unit 105, that is, the material and structure of the voice tube. In the detection unit 10 of the present embodiment, the reverberation time is 200 μs. In the present embodiment, the sound velocity is a sound velocity of 331.5 m / s under the slowest condition of 0 ° C. under a temperature range of 0 ° C. to 40 ° C. that is assumed as a condition for using the image reading apparatus 1. Accordingly, since the first distance L1 = 40 mm and the second distance L2 = 50 mm, the first distance L1 and the second distance L2 are 33.15 mm (= 200 μs × 331.5 m / s ÷ 2) <L1 <L2 Meet. When the first distance L1 and the second distance L2 satisfy 33.15 mm <L1 <L2, it is possible to prevent the reverberation from affecting the accuracy of specifying an abnormality occurrence location. That is, the reverberation generated in the reception-side transmission unit 105 when an ultrasonic wave is received by a specific opening of the reception-side openings 104A, 104B, and 104C is generated after the specific opening receives the ultrasonic waves. The ultrasonic wave is not left in the reception-side transmission unit 105 until the ultrasonic wave is received by the openings adjacent to each other in the specific opening. As shown in FIG. 6, when reverberation remains until an ultrasonic wave is received by an adjacent opening, the ultrasonic wave and reverberation received by the adjacent openings overlap each other. When the ultrasonic wave and the reverberation are superposed in this manner, the amplitude of the ultrasonic wave increases or decreases. Therefore, the superimposition of the ultrasonic wave and the reverberation hinders the determination accuracy when determining whether or not an abnormality has occurred in the conveyance of the sheet SH. However, if the first distance L1 and the second distance L2 satisfy 33.15 mm <L1 <L2, it is possible to prevent the accuracy in determining the occurrence of an abnormality in the sheet SH being conveyed due to reverberation.

[Electrical configuration of image reading apparatus]
With reference to FIG. 7, an electrical configuration related to specifying an abnormality occurrence location in the electrical configuration of the image reading apparatus 1 will be described. FIG. 7 is a diagram illustrating an electrical configuration related to specifying an abnormality occurrence location in the electrical configuration of the image reading apparatus 1. As shown in FIG. 7, the control unit 7 includes a CPU 71, a RAM 72, a ROM 73, a drive signal generation unit 74, an amplification unit 75, a sample hold circuit 76, an AD conversion unit 77, and a bus 78. Prepare.

  The CPU 71 is an arithmetic processing device that executes various functions provided in the image reading apparatus 1 by executing various information processing programs. The RAM 72 is an area for temporarily storing various data such as ultrasonic amplitude data received by the ultrasonic receiving unit 106 and image data of the sheet SH read by the reading sensor 31. The ROM 73 stores various information processing programs executed by the CPU 71. The ROM 73 stores the time interval PR, the time P1, the time P2, the time PS, the amplitude value of the ultrasonic wave received by the ultrasonic wave receiving unit 106 when not passing through the sheet SH (hereinafter referred to as “threshold”), and the like. Various data are also stored. The ROM 73 is configured by a flash memory that is a nonvolatile memory. The CPU 71, RAM 72, and ROM 73 are respectively connected to a data communication bus 78, and transmit and receive various types of information via the bus 78. The bus 78 is connected to the setting unit 5 and the display unit 6. When the CPU 71 determines that an abnormality has occurred, command information for notifying the display unit 6 of the occurrence of the abnormality is supplied via the bus 78.

  The drive signal generation unit 74 generates a drive signal for driving the ultrasonic transmission unit 10A. The drive signal generation unit 74 supplies the generated drive signal to the ultrasonic transmission unit 10A. The ultrasonic transmission unit 10A generates ultrasonic waves based on the supplied drive signal. As illustrated in FIG. 3 and the like, the ultrasonic transmission unit 10A transmits the generated ultrasonic waves toward the ultrasonic reception unit 10B. When the sheet SH is conveyed between the ultrasonic transmission unit 10A and the ultrasonic reception unit 10B, the ultrasonic wave is attenuated and received by the ultrasonic reception unit 10B.

  The amplifying unit 75 amplifies the ultrasonic analog signal received by the ultrasonic receiving unit 10B. The sample hold circuit 76 samples the peak value of the ultrasonic analog signal amplified by the amplification unit 75. The sample hold circuit 76 temporarily holds the sampled values in association with the predetermined time points TS1, TS2, and TS3 during the time PS shown in FIG. The predetermined time points TS1, TS2, and TS3 are obtained by the CPU 71 each time an ultrasonic wave is received by the ultrasonic wave receiving unit 106 based on the data of the time interval PR, the time P1, the time P2, and the time PS stored in the ROM 73. It is determined. The time points TS1, TS2, and TS3 correspond to the time points at which the ultrasonic wave reception unit 106 receives ultrasonic waves through the reception side openings 104B, 104A, and 104C, respectively. By sampling and temporary holding by the sampling hold circuit 76, the amplitude of the ultrasonic wave received by the ultrasonic wave receiving unit 106 is determined in association with the time point when the ultrasonic wave is received by the ultrasonic wave receiving unit 106. The AD converter 77 converts the ultrasonic analog data temporarily held by the sample hold circuit 76 into digital data. The RAM 72 temporarily stores the ultrasonic data converted into digital data by the AD conversion unit 77 in association with the time when the ultrasonic wave is received by the ultrasonic receiving unit 106. That is, as shown in FIG. 5C, the RAM 72 generates three ultrasonic waves derived from one ultrasonic wave generated by the ultrasonic wave generation unit 101 at each time interval PR, respectively, at time points TS1, TS2, and Store in association with TS3.

[Control of image reading apparatus]
Hereinafter, the control of the image reading apparatus 1 will be described with reference to FIG. FIG. 8 is a flowchart showing the control of the image reading apparatus 1. A series of processing is executed by the CPU 71 shown in FIG. When the user presses the power switch of the setting unit 5, a power ON command is supplied from the setting unit 5 to the CPU 71. When a power-on command is supplied to the CPU 71, the image reading apparatus 1 starts to be driven. At the same time, the CPU 71 executes a series of processes shown below.

  In the process shown in FIG. 8, first, various parameters, flags, and the like are initialized (step 0, hereinafter referred to as “S0”). In S0, the number of times of arrival at the specific location shown below is set to zero.

  When initialization is performed, the ultrasonic transmission unit 10A is driven (S1). That is, an ultrasonic wave is generated. The generated ultrasonic wave is transmitted from the ultrasonic wave transmitting unit 10A. The ultrasonic waves transmitted from the ultrasonic transmission unit 10A are received by the ultrasonic reception unit 10B. The received ultrasonic analog signal is amplified by the amplifying unit 75, and the sample hold circuit 76 performs sampling and temporary holding of the peak value of the amplified ultrasonic analog signal. When sampling and temporary holding are performed, the analog analog data of the ultrasonic wave temporarily held by the sample hold circuit 76 is converted into digital data by the AD conversion unit 77. The ultrasonic data converted into digital data is temporarily stored in the RAM 72 as ultrasonic waves WA, WB, and WC associated with the time points TS1, TS2, and TS3.

  When the reception up to the time point TS3 is completed, the data of the three ultrasonic waves WA, WB, and WC stored in the RAM 72 are read from the RAM 72 together with the time points TS1, TS2, and TS3 (S2).

  It is determined whether there is a data value less than a threshold value among the read ultrasonic wave WA, WB, and WC data (S3). That is, the ultrasonic waves WA, WB, and WC are compared with the threshold value of the amplitude value of the ultrasonic wave received by the ultrasonic wave receiving unit 106 when not passing through the sheet SH stored in the ROM 73. If it is determined that there is no data value less than the threshold value among the read ultrasonic wave WA, WB, and WC data (S3: No), the process proceeds to S6. In S <b> 6, it is determined whether or not the conveyance of the sheet SH has ended, that is, whether or not the setting unit 5 has been operated and an end command has been supplied to the control unit 7. If it is determined that the conveyance of the sheet SH has not ended (S6: No), the process returns to S1. If it is determined that the conveyance of the sheet SH has been completed (S6: Yes), after resetting the number of arrivals at the specific location in S8, all the processes shown in FIG. 8 are completed.

  In S3, when it is determined that there is a data value less than the threshold value among the read data of the ultrasonic waves WA, WB, and WC (S3: Yes), the number of arrivals at the specific location is incremented (S4). That is, when it is determined in S3 that the ultrasonic wave WA is attenuated, the AA arrival count indicating that the sheet SH has reached the specific location AA is incremented. If it is determined in S3 that the ultrasonic wave WB is attenuated, the AB arrival count indicating that the sheet SH has reached the specific location AB is incremented. If it is determined in S3 that the ultrasonic wave WC is attenuated, the number of AC arrivals indicating that the sheet SH has reached the specific location AC is incremented. The number of times of arrival at the specific location is configured by the number of times of reaching AA, the number of times of reaching AB, and the number of times of reaching AC. The specific location arrival count is stored in the RAM 72.

  When the specific part arrival count is incremented, it is determined whether or not the sheet SH is waiting in any one of the specific parts WA, WB, and WC for a predetermined time or more (S5). That is, it is determined whether or not there are more than the predetermined number stored in advance in the ROM 73 among the AA arrival times, the AB arrival times, and the AC arrival times. If there are more than a predetermined number of AA arrival times, AB arrival times, and AC arrival times, the sheet SH waits for a predetermined time or more at a specific location corresponding to each number. Therefore, it can be determined that a jam has occurred in any one of the specific locations AA, AB, and AC. If it is determined that the sheet SH is not waiting in any one of the specific locations WA, WB, and WC for a predetermined time or longer (S5: No), the process proceeds to S6.

  The processes shown in S3, S4, and S5 will be described in detail with reference to FIG. In FIG. 9, the horizontal axis indicates a time TM during which an ultrasonic wave is received by the ultrasonic wave receiver 106. In FIG. 9, the vertical axis indicates the amplitude AM of the ultrasonic wave received by the ultrasonic receiving unit 106.

  As shown in FIG. 9, when the sheet SH reaches the specific location AB, the amplitude of the ultrasonic wave WB obtained through the reception side opening 104B is attenuated. When a jam occurs at the specific location AB, the sheet SH continues to stay at the specific location AB. Therefore, as shown in FIG. 9, the attenuated ultrasonic wave WB data continues to be received. If the attenuated ultrasonic wave WB continues to be received, the AB arrival count continues to be incremented, and the AB arrival count increases. Therefore, when the number of times AB has reached a predetermined number of times or more set in advance, it can be seen that the sheet SH remains at the specific location AB, and it can be detected that a jam has occurred at the specific location AB.

  If it is determined that the sheet SH has been waiting for one or more of the specific locations WA, WB, and WC for a predetermined time (S5: Yes), the location where the abnormality has occurred is notified (S7). In other words, the display unit 6 is supplied with an image signal for displaying a message “jamming” indicating that a jam has occurred and a message indicating the location where the jam has occurred. The display unit 6 displays a message based on the supplied image signal. For example, when it is determined that the sheet SH is waiting at the specific location WB, a message “Jam is generated near the conveyance roller” is displayed.

  When the abnormality occurrence location is notified, the specific location arrival count is reset (S8). That is, the number of times of arrival at the specific location is initialized to zero. When the number of times of arrival at the specific location is reset, all processing of the image reading apparatus 1 is completed.

(Second Embodiment)

  In the first embodiment, as an example of abnormality detection, the image reading apparatus 1 detects whether or not a jam has occurred at a specific location by the detection unit 10. However, the present invention is not limited to jamming, and for example, abnormality detection such as double feeding and idle feeding may be performed. As an example, an example in which the detection unit 10 is applied to double feed detection in the second embodiment described below will be described.

  The image reading apparatus 1 in the second embodiment has the same mechanical configuration and electrical configuration as the image reading apparatus 1 in the first embodiment. The image reading apparatus 1 in the second embodiment performs control that is partially different from that of the image reading apparatus 1 in the first embodiment only for control. FIG. 10 is a flowchart showing a part of the control in the second embodiment. A series of processing is executed by the CPU 71 shown in FIG. When the user presses the power switch of the setting unit 5, a power ON command is supplied from the setting unit 5 to the CPU 71. When a power-on command is supplied to the CPU 71, the image reading apparatus 1 starts to be driven. At the same time, the CPU 71 executes a series of processes shown below.

  In the process shown in FIG. 10, first, various parameters, flags, and the like are initialized (step X0, hereinafter referred to as “SX0”). In S0, the following number of non-conveyance states is set to zero.

  When initialization is performed, the ultrasonic transmission unit 10A is driven (SX1). That is, an ultrasonic wave is generated. The generated ultrasonic wave is transmitted from the ultrasonic wave transmitting unit 10A. The ultrasonic waves transmitted from the ultrasonic transmission unit 10A are received by the ultrasonic reception unit 10B. The received ultrasonic analog signal is amplified by the amplifying unit 75, and the sample hold circuit 76 performs sampling and temporary holding of the peak value of the amplified ultrasonic analog signal. When sampling and temporary holding are performed, the analog analog data of the ultrasonic wave temporarily held by the sample hold circuit 76 is converted into digital data by the AD conversion unit 77. The ultrasonic data converted into digital data is temporarily stored in the RAM 72 as ultrasonic waves WA, WB, and WC associated with the time points TS1, TS2, and TS3.

  When the reception up to the time point TS3 is completed, the data of the three ultrasonic waves WA, WB, and WC stored in the RAM 72 are read from the RAM 72 together with the time points TS1, TS2, and TS3 (SX2).

  It is determined whether there is data less than the first threshold among the read ultrasonic wave WA, WB, and WC data (SX3). That is, the ultrasonic waves WA, WB, and WC are compared with the first threshold value of the amplitude value of the attenuated ultrasonic wave received by the ultrasonic wave receiving unit 106 when two or more sheets SH stored in the ROM 73 are passed through. The If it is determined that there is a data value less than the first threshold among the read ultrasonic wave WA, WB, and WC data, that is, it is determined that double feed has occurred at a specific location (SX3: Yes), double feed The occurrence location is notified (SX4). That is, the display unit 6 is supplied with an image signal for displaying a message “double feed occurrence” indicating that a double feed has occurred and a message indicating a location where the double feed has occurred. The display unit 6 displays a message based on the supplied image signal. For example, if it is determined that double feed has occurred at the specific location WB, a message “Double feed has occurred near the transport roller” is displayed. When the double feed occurrence location is notified, the process proceeds to SX9, and a reset of the number of non-conveyance states described later is executed (SX9).

  If it is determined that there is no data value less than the first threshold value among the read ultrasonic wave WA, WB, and WC data, that is, no double feed has occurred (SX3: No), the ultrasonic waves WA and WB. , It is determined whether there is data less than the second threshold among the WC data (SX5). That is, the amplitude values of the ultrasonic waves WA, WB, and WC are compared with the second threshold value of the amplitude value of the attenuated ultrasonic wave received by the ultrasonic wave receiving unit 106 when passing through one sheet SH stored in the ROM 73. The If it is determined that there is data less than the second threshold value, that is, one sheet is normally conveyed at any of the specific locations (SX5: Yes), the process returns to SX1. If it is determined that there is no data value less than the second threshold value, that is, it is determined that the sheet SH is not being transported in any of the specific locations (SX5: No), the number of non-transport states is incremented ( SX6). The number of non-conveyance states is the number of times indicating the length of time when the sheet SH is not being conveyed in the image reading apparatus 1. When the number of non-conveyance states exceeds a predetermined number of times, it is detected that the sheet SH has not been conveyed in the image reading device 1 for a predetermined time or more, that is, the user has not used the image reading device 1 for a predetermined time or more. can do.

  When the non-conveyance state count is incremented, it is determined whether or not the sheet SH has not been conveyed for a predetermined time or more (SX7). That is, it is determined whether or not the number of non-conveyance states exceeds a predetermined number stored in the ROM 73. If it is determined that the sheet SH is being conveyed (SX7: No), the process returns to SX1. If it is determined that the sheet SH has not been conveyed for a predetermined time or longer (SX7: Yes), whether or not the conveyance of the sheet SH has been completed, that is, whether the setting unit 5 has been operated and an end command has been supplied to the control unit 7 It is determined whether or not (SX8). If it is determined that the conveyance of the sheet SH has not been completed (SX8: No), the process returns to SX1. If it is determined that the conveyance of the sheet SH has been completed (SX8: Yes), after resetting the number of non-conveyance states in SX9, all the processes shown in FIG. 10 are completed.

(Modification)
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. An example of the modification will be described below. In the modification shown below, the same structure as the said embodiment is attached | subjected and demonstrated with the same number.

  In the above embodiment, the detection unit 10 has a shape in which the transmission-side transmission unit 102 and the reception-side transmission unit 105 extend in the X-axis direction. However, the present invention is not limited to this, and the transmission-side transmission unit and the reception-side transmission unit meander in the sheet conveyance direction, for example, like the transmission-side transmission units 202 and 302 shown in FIGS. It may be a shape. Since the transmission-side transmission unit and the reception-side transmission unit meander in the sheet conveyance direction, the transmission-side transmission unit and the reception-side transmission unit are as shown in FIG. 11 and FIG. A bent portion CR is provided. An ultrasonic transmission unit 200A illustrated in FIG. 11 includes an ultrasonic generation unit 201, a transmission-side transmission unit 202, and transmission-side openings 203A, 203B, 203C, and 203D. An ultrasonic transmission unit 300A illustrated in FIG. 12 includes an ultrasonic generation unit 301, a transmission-side transmission unit 302, and transmission-side openings 303A, 303B, 303C, and 303D. 11 and 12, the transmission side openings 303A to 303D and the transmission side openings 303A to 303D are formed below the transmission side transmission parts 202 and 302, respectively. Reference numeral 12 denotes a broken line. In the modification shown in FIGS. 11 and 12, the reception-side transmission unit has the same configuration as the transmission-side transmission units 202 and 302 shown in FIGS. As shown in FIGS. 11 and 12, by configuring the transmission-side transmission unit and the reception-side transmission unit, the ultrasonic path in the transmission-side transmission unit and the reception-side transmission unit can be bent. it can. Therefore, for example, ultrasonic waves meander as shown by an arrow MD shown in FIG. 11 in the transmission-side transmission unit 202 from the transmission-side opening 203B to the transmission-side opening 203A. On the other hand, when the transmission-side transmission unit extends in the conveyance direction, the ultrasonic wave is indicated by an arrow ST shown in FIG. 11 in the transmission-side transmission unit 202 from the transmission-side opening 203B to the transmission-side opening 203A. So go straight. Therefore, like the transmission-side transmission units 202 and 302 shown in FIGS. 11 and 12, the transmission unit includes the bent portion CR, so that the distance can be increased in the conveyance direction. In order to avoid the influence of reverberation, it is usually considered to increase the distance in the transport direction between the plurality of transmission openings and the reception openings. However, when the distance in the conveyance direction between the plurality of transmission openings and the plurality of reception openings is increased, there arises a problem that the apparatus becomes large. In this modification, in order to avoid the influence of reverberation, it is not necessary to increase the distance in the transport direction between the plurality of transmission side openings and the plurality of reception side openings. Accordingly, it is possible to specify the location where the sheet conveyance abnormality has occurred with a simple configuration while reducing the size of the apparatus in the conveyance direction. The transmission-side transmission unit and the reception-side transmission unit may have any shape as long as it has a bent portion such as a spiral shape or a coil shape other than the shape meandering in the sheet conveyance direction.

  In the above-described embodiment, the action unit acting on the sheet includes a conveyance roller 36 that is a conveyance unit that conveys the sheet, a first separation piece 33 that is a separation unit that conveys the sheet while separating the sheet, and a second separation piece 35. Etc. However, the present invention is not limited to this, and the action unit may be, for example, an image forming unit that forms an image by discharging ink or the like onto a sheet.

  In the above embodiment, the detection unit 10 includes the transmission side openings 103A, 103B, and 103C, and the reception side openings 104A, 104B, and 104C, and the three reception side openings. However, the present invention is not limited to this, and the detection unit may include, for example, two transmission-side openings and two reception-side openings, or a number of transmission-side openings and reception-side openings. Also good.

  In the above embodiment, the ultrasonic transmitter 10A and the ultrasonic receiver 10B are arranged at the same position with respect to the X-axis direction as shown in FIG. However, the present invention is not limited thereto, and the ultrasonic transmission unit and the ultrasonic reception unit may be arranged so that, for example, a line connecting the transmission side opening and the reception side opening crosses the sheet surface obliquely. . Note that “obliquely intersect” means that the reflected waves of the ultrasound intersect at an angle so that they do not return to the ultrasound transmitter. For example, this intersection angle may be set from geometric conditions such as the opening size of the transmission side opening, the distance from the reflecting sheet, or the reflection state of the reflected wave. By configuring the detection unit in this way, the ultrasonic wave transmitted from the transmission side opening and reflected by the sheet does not return to the transmission side opening again. Therefore, it is possible to prevent the amplitude value of the ultrasonic wave received by the ultrasonic wave receiving unit from becoming unstable due to the influence of the reflected wave. Therefore, compared with the case where the transmission side opening and the reception side opening are arranged so that the line connecting the transmission side opening and the reception side opening is orthogonal to the sheet to be conveyed, the abnormality is more accurate. It can be connected to the location of occurrence.

  In the above embodiment, the ultrasonic generator 101 and the ultrasonic receiver 106 are arranged at the same position in the Y-axis direction. However, the present invention is not limited to this. For example, the ultrasonic wave generation unit 101 and the ultrasonic wave reception unit 106 may be arranged at positions shifted from each other in the Y-axis direction within a range that does not hinder the location of the abnormality occurrence. Good.

  In the above-described embodiment, the transmission-side transmission unit 102 and the transmission-side openings 103A, 103B, and 103C, and the reception-side transmission unit 105 and the reception-side openings 104A, 104B, and 104C are hollow acoustic tubes made of a hard plastic material. It was made up of. However, not limited to this, for example, the transmission-side transmission unit and the reception-side transmission unit may be configured by solid elements that are not hollow.

  In the above-described embodiment, the sheet feed scanner has been described as an example of the image reading apparatus. However, the image feeding apparatus is not limited thereto, and may be, for example, a reading unit of a multifunction machine with a FAX and an automatic conveyance function. Further, the detection unit may be used for specifying an abnormality occurrence location in the paper feed mechanism of the printing press.

  In the above embodiment, the reception side openings 104A, 104B, and 104C are located at the same positions as the transmission side openings 103A, 103B, and 103C in the Y-axis direction, respectively. However, the present invention is not limited to this, and for example, the receiving side openings may be positioned about 0.1 mm away from the transmitting side openings in the Y-axis direction. That is, each reception side opening may be located at a position where at least the ultrasonic wave transmitted from the transmission side opening can be received in the Y-axis direction.

  In the above-described embodiment, the image reading apparatus 1 notifies the occurrence of the abnormality by the display unit 6 when the occurrence of the abnormality is detected. However, the present invention is not limited to this. You may alert | report by stopping reading operation on the way.

  In the above embodiment, the image reading apparatus 1 determines whether or not an abnormality has occurred in the sheet SH. However, the present invention is not limited to this. For example, the detection unit 10 may include a determination unit, and the detection unit 10 may determine whether an abnormality has occurred in the sheet SH.

  In order to reduce reverberation, for example, the detection unit may include a sound absorbing material at both ends of the transmission-side transmission unit and the reception-side transmission unit.

  You may use a detection part as a sensor for detecting whether the sheet | seat is mounted in the paper feed tray together with abnormality detection. In this case, the transmission-side transmission unit and the reception-side transmission unit are extended to the vicinity of the paper feed tray, and transmitted from the transmission side opening on the paper feed tray to the reception side opening below the paper feed tray. What is necessary is just to provide the through-hole etc. through which the ultrasonic wave to be passed. In this case, after the detection unit detects that the sheet is placed on the paper feed tray, the conveyance and reading of the sheet may be started.

  The sheet may be anything as long as it is conveyed, such as paper, cardboard, plastic card, fabric, or a sheet fed from a roll sheet.

DESCRIPTION OF SYMBOLS 1 Image reader 6 Display part 10 Detection part 10A Ultrasonic transmission part 10B Ultrasonic reception part 101 Ultrasonic wave generation part 102 Transmission side transmission part 103A, 103B, 103C Transmission side opening part 104A, 104B, 104C Reception side opening part 105 Receiving side transmission unit 106 Ultrasonic wave receiving unit 31 Reading sensor 32 Pickup roller 33 First separation piece 34 Second separation roller 35 Second separation piece 36 Conveying roller 37 Conveying driven roller 71 CPU
72 RAM
73 ROM
200A Ultrasonic transmitter 201 Ultrasonic generator 202 Transmission side transmission unit 203A, 203B, 203C Transmission side opening 300A Ultrasonic transmission unit 301 Ultrasonic generation unit 302 Transmission side transmission unit 303A, 303B, 303C Transmission side opening

Claims (7)

A sheet conveying apparatus for conveying a sheet,
An ultrasonic generator that generates pulsed ultrasonic waves;
A plurality of transmission side openings that are arranged at different positions with respect to the conveyance direction of the sheet and transmit the ultrasonic waves;
A transmission-side transmission unit coupled to the ultrasonic generation unit and the plurality of transmission-side openings, and transmitting the ultrasonic waves generated by the ultrasonic generation unit to the plurality of transmission-side openings;
A plurality of the ultrasonic waves transmitted from the plurality of transmission side openings are arranged at positions different from each other in the sheet conveyance direction, are opposed to the plurality of transmission side openings with the sheet interposed therebetween. A receiving side opening;
An ultrasonic receiver for receiving the ultrasonic waves received by the plurality of receiving side openings;
A reception-side transmission unit coupled to a plurality of reception-side openings and the ultrasonic reception unit, and transmitting the ultrasonic waves received by the plurality of reception-side openings to the ultrasonic reception unit;
Abnormality in the conveyance of the sheet based on the time when the ultrasonic wave is received by the ultrasonic wave receiving unit through the plurality of reception side openings and the amplitude value of the ultrasonic wave received by the ultrasonic wave receiving unit A determination unit that determines whether or not
The path lengths of the plurality of paths from the ultrasonic wave generation unit to the ultrasonic wave reception unit via the transmission side transmission unit, the plurality of transmission side openings, and the plurality of reception side openings are different. A sheet conveying apparatus having a length. A plurality of action portions arranged along the conveyance direction of the sheet and acting on the sheet;
The plurality of transmission side openings are arranged with the plurality of action portions sandwiched in the sheet conveyance direction,
The sheet conveying apparatus according to claim 1, wherein the plurality of reception side openings are arranged with the plurality of action portions interposed therebetween in the sheet conveying direction. Comprising at least three transmitting side openings and at least three receiving side openings;
Of the at least three transmission side openings, the distance between the two transmission side openings adjacent in the transmission side transmission part, and among the at least three reception side openings, the reception side transmission The distance between two reception side openings adjacent to each other in the unit is obtained by multiplying the reverberation time and the sound speed depending on the configuration of the transmission side transmission unit and the reception side transmission unit, respectively. The sheet conveying apparatus according to claim 1, wherein the distance is equal to or greater than half of the value.   The sheet transmission device according to claim 1, wherein the transmission-side transmission unit and the reception-side transmission unit include a bent portion.   5. The transmission-side transmission unit, the plurality of transmission-side openings, the reception-side transmission unit, and the plurality of reception-side openings are each configured by a voice tube. The sheet conveying apparatus in any one of.   The sheet conveying apparatus according to any one of claims 1 to 5, further comprising a notifying unit for notifying whether or not an abnormality has occurred based on a determination result of the determining unit. A sheet conveying device according to any one of claims 1 to 6;
An image reading apparatus comprising: a reading unit that reads an image of the sheet conveyed by the sheet conveying apparatus.

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