Ultrasonic device and media transport device

Abstract

To solve a problem in which an ultrasonic device supporting a protective member on a shield part has difficulty of suppressing reduction of detection accuracy caused by multiple reflection of ultrasonic wave by the protective member and reflection of ultrasonic wave by the shield part.SOLUTION: An ultrasonic device comprises: an ultrasonic element which has a transmission surface transmitting an ultrasonic wave, and transmits the ultrasonic wave in a transmission direction crossing the transmission surface; a wiring which is arranged on a transmission surface outer periphery of the transmission surface, and connected to the ultrasonic element; a shield member covering the wiring; a holding member which is arranged on shield outer periphery of the shield member, and extended in the transmission direction; and a protective member which opposes the transmission surface, has pores through which the ultrasonic wave passes. A shield opening opposing the transmission surface is provided for the shield member; a holding member opening opposing the transmission surface is provided for the holding member; and the protective member is arranged for the holding member opening.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an ultrasonic device and a medium conveyance device.

Background Art

[0002] An ultrasonic device that detects an object using ultrasonic waves is known. The ultrasonic device described in Patent Document 1 detects double feeding of a sheet. The ultrasonic device includes an ultrasonic element, a shield portion, and a protection member. The ultrasonic element transmits ultrasonic waves along a first axis. The shield portion extends along the first axis and has a through hole that allows ultrasonic waves to pass through at an extending tip portion. The protection member is provided to cover the through hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an ultrasonic device that supports a protection member with a shield portion, it is difficult to suppress a decrease in detection accuracy due to multiple reflection of ultrasonic waves by the protection member and reflection of ultrasonic waves by the shield portion.

Means for Solving the Problems

[0005] The ultrasonic device of this disclosure includes an ultrasonic element having a transmitting surface for transmitting ultrasonic waves, transmitting ultrasonic waves in a transmitting direction intersecting the transmitting surface, wiring arranged on the outer periphery of the transmitting surface and connected to the ultrasonic element, a shielding member covering the wiring, a holding member arranged on the outer shield of the shielding member and extending in the transmitting direction, and a protective member facing the transmitting surface and having a hole for passing the ultrasonic waves, wherein the shielding member is provided with a shielding opening facing the transmitting surface, the holding member is provided with a holding member opening facing the transmitting surface, and the protective member is arranged in the holding member opening.

[0006] The media transport device of the present disclosure is a media transport device for transporting a medium, comprising: a media transport path for transporting the medium; a holding member having a holding member opening; an ultrasonic element disposed away from the media transport path relative to the holding member and transmitting ultrasonic waves; wiring disposed on the outer circumference of the transmitting surface of the ultrasonic element and connected to the ultrasonic element; a shielding member covering the wiring; and a protective member facing the transmitting surface of the ultrasonic element and having a hole for passing the ultrasonic waves, wherein the shielding member is provided with a shielding opening facing the transmitting surface, the holding member opening faces the transmitting surface, and the protective member is disposed in the holding member opening. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing the external configuration of an image scanner. [Figure 2] A diagram showing the general configuration of an image scanner. [Figure 3] A diagram showing the schematic configuration of the transmission unit. [Figure 4] A diagram showing the schematic configuration of the transmission unit. [Figure 5] A diagram showing the relationship between an ultrasonic array and wiring shielding. [Figure 6] A diagram showing the schematic configuration of a circuit board. [Figure 7] A diagram showing the schematic configuration of the array aperture. [Figure 8]A diagram showing the output distribution of ultrasound waves transmitted from an ultrasound array. [Figure 9] A diagram showing the relationship between an ultrasonic array and wiring shielding. [Figure 10] A diagram showing the general configuration of the filter. [Figure 11] A diagram showing the schematic configuration around the ultrasonic sensor. [Figure 12] A diagram showing the schematic configuration around the ultrasonic sensor. [Modes for carrying out the invention]

[0008] Figure 1 shows the external configuration of the image scanner 1. Figure 1 shows a perspective view of the image scanner 1. The image scanner 1 is an example of an electronic device equipped with an ultrasonic sensor 9. The image scanner 1 is a reading device that reads a document M. The image scanner 1 corresponds to an example of a media transport device. The document M corresponds to an example of a medium. The image scanner 1 comprises an outer casing 2 and a document support 3.

[0009] The outer casing 2 forms the outer perimeter of the image scanner 1. The outer casing 2 covers the reading unit 8, ultrasonic sensor 9, transport path 12, etc. The reading unit 8, ultrasonic sensor 9, and transport path 12 will be described later. The outer casing 2 is provided with a supply port 4 and an outlet port 5.

[0010] The document support 3 holds the document M. The document support 3 is configured to hold multiple documents M. The document support 3 is positioned above the outer casing 2. The document support 3 is located at a position where it connects to the feed port 4.

[0011] The supply port 4 supplies the document M, which is placed on the document support 3, into the interior of the outer casing 2. The supply port 4 is connected to the document support 3. The supply port 4 is located above the outer casing 2. The document M supplied from the supply port 4 is read by the scanning unit 8.

[0012] The discharge port 5 discharges the document M conveyed inside the exterior 2 to the outside of the exterior 2. The discharge port 5 discharges the document M read by the reading unit 8 to the outside of the exterior 2. The discharge port 5 is provided below the exterior 2.

[0013] FIG. 2 shows a schematic configuration of the image scanner 1. FIG. 2 schematically shows the image scanner 1. The image scanner 1 includes a conveyance mechanism 7, a reading unit 8, an ultrasonic sensor 9, and a control unit 11 inside the exterior 2.

[0014] The conveyance mechanism 7 conveys the document M supplied from the supply port 4 in the conveyance direction T toward the discharge port 5. The conveyance mechanism 7 conveys the document M from above to below the exterior 2. The document M is not limited to paper. The document M may be composed of a film, a fabric, or the like. The conveyance mechanism 7 conveys the documents M placed on the document support 3 one by one. The conveyance mechanism 7 corresponds to an example of a medium conveyance device. The conveyance mechanism 7 includes a conveyance path 12, a first conveyance roller pair 13, a second conveyance roller pair 14, a third conveyance roller pair 15, and a fourth conveyance roller pair 16.

[0015] The conveyance path 12 is a movement path of the document M from the supply port 4 to the discharge port 5. The document M is conveyed from the supply port 4 to the discharge port 5 along the conveyance path 12. Along the conveyance path 12, the first conveyance roller pair 13, the second conveyance roller pair 14, the third conveyance roller pair 15, and the fourth conveyance roller pair 16 are arranged. The conveyance path 12 corresponds to an example of a medium conveyance path.

[0016] The first conveyance roller pair 13 conveys the document M supplied to the supply port 4 along the conveyance path 12. When a plurality of documents M are placed on the document support 3, the first conveyance roller pair 13 supplies the document M located at the uppermost position among the plurality of documents M into the conveyance path 12. The first conveyance roller pair 13 includes a first driving roller 13a and a first driven roller 13b.

[0017] The first driving roller 13a transmits the driving force for conveying the document M. The first driving roller 13a is rotationally driven by the driving force of a conveyance motor 17 described later. The first driving roller 13a conveys the document M along the conveyance path 12 by rotationally driving.

[0018] The first driven roller 13b contacts the first driving roller 13a. The first driven roller 13b is driven to rotate passively when the first driving roller 13a is rotationally driven. The first driven roller 13b sandwiches the first driving roller 13a and the document M and conveys the document M along the conveyance path 12.

[0019] The second pair of conveyance rollers 14 is arranged downstream in the conveyance direction T with respect to the first pair of conveyance rollers 13. The second pair of conveyance rollers 14 conveys the document M conveyed by the first pair of conveyance rollers 13 along the conveyance path 12. The second pair of conveyance rollers 14 functions as a separating mechanism for separating the documents M conveyed by the first pair of conveyance rollers 13 one by one. The second pair of conveyance rollers 14 includes a second driving roller 14a and a second driven roller 14b.

[0020] The second driving roller 14a transmits the driving force for conveying the document M. The second driving roller 14a is rotationally driven by the driving force of the conveyance motor 17. The second driving roller 14a conveys the document M along the conveyance path 12 by rotationally driving.

[0021] The second driven roller 14b contacts the second driving roller 14a. The second driven roller 14b is driven to rotate passively when the second driving roller 14a is rotationally driven. The second driven roller 14b sandwiches the second driving roller 14a and the document M and conveys the document M along the conveyance path 12. The friction coefficient of the outer peripheral surface of the second driven roller 14b with respect to the document M is larger than the friction coefficient of the outer peripheral surface of the second driving roller 14a with respect to the document M. The documents M are separated one by one by the rotation of the second pair of conveyance rollers 14.

[0022] The third transport roller pair 15 is positioned downstream of the second transport roller pair 14 in the transport direction T. The third transport roller pair 15 transports the document M transported by the second transport roller pair 14 along the transport path 12. The third transport roller pair 15 comprises a third drive roller 15a and a third driven roller 15b.

[0023] The third drive roller 15a transmits the driving force to transport the document M. The third drive roller 15a is rotationally driven by the driving force of the transport motor 17. By rotating, the third drive roller 15a transports the document M along the transport path 12.

[0024] The third driven roller 15b is in contact with the third drive roller 15a. The third driven roller 15b rotates in response to the rotational drive of the third drive roller 15a. The third driven roller 15b grips the document M with the third drive roller 15a and transports the document M along the transport path 12.

[0025] The fourth transport roller pair 16 is positioned downstream of the third transport roller pair 15 in the transport direction T. The fourth transport roller pair 16 transports the document M transported by the third transport roller pair 15 along the transport path 12. The fourth transport roller pair 16 transports the document M toward the discharge port 5. The fourth transport roller pair 16 comprises a fourth drive roller 16a and a fourth driven roller 16b.

[0026] The fourth drive roller 16a transmits the driving force to transport the document M. The fourth drive roller 16a is rotationally driven by the driving force of the transport motor 17. By rotating, the fourth drive roller 16a transports the document M along the transport path 12.

[0027] The fourth driven roller 16b is in contact with the fourth drive roller 16a. The fourth driven roller 16b rotates in response to the rotational drive of the fourth drive roller 16a. The fourth driven roller 16b grips the document M with the fourth drive roller 16a and transports the document M along the transport path 12.

[0028] The reading unit 8 reads the original document M as it is transported along the transport path 12. The reading unit 8 is positioned along the transport path 12. In the image scanner 1 shown in Figure 2, the reading unit 8 is positioned between the third transport roller pair 15 and the fourth transport roller pair 16. The reading unit 8 comprises a first scanner 8a and a second scanner 8b.

[0029] The first scanner 8a reads the first surface of the document M being transported along the transport path 12. The first scanner 8a is positioned along the transport path 12, on one side of the transport path 12. The first scanner 8a reads the first surface of the document M and generates first read data. The first scanner 8a includes a first light source 18a and a first image sensor 19a.

[0030] The first light source 18a illuminates the first surface of the original document M. The first light source 18a is positioned opposite the first surface of the original document M. The first light source 18a illuminates the original document M along the original document width direction, which is perpendicular to the transport direction T of the original document M.

[0031] The first image sensor 19a receives light reflected from the first surface of the document M. By receiving this light, the first image sensor 19a reads the first surface of the document M. The first image sensor 19a is configured to extend in the width direction of the document.

[0032] The first scanner 8a illuminates the first surface of the original document M with light from the first light source 18a, and the first image sensor 19a receives the light reflected from the first surface of the original document M. The first image sensor 19a reads the first surface of the original document M by receiving the light reflected from the first surface of the original document M.

[0033] The second scanner 8b reads the second side of the document M as it is transported along the transport path 12. The second side of the document M is the back side of the first side of the document M. The second scanner 8b is positioned along the transport path 12, on the other side of the transport path 12. The second scanner 8b may be positioned opposite the first scanner 8a. The second scanner 8b reads the second side of the document M and generates second scan data. The second scanner 8b includes a second light source 18b and a second image sensor 19b.

[0034] The second light source 18b illuminates the second surface of the original document M. The second light source 18b is positioned opposite the second surface of the original document M. The second light source 18b illuminates the original document width direction perpendicular to the transport direction T of the original document M. The configuration of the second light source 18b may be the same as or different from that of the first light source 18a. It is preferable that the configuration of the second light source 18b is the same as that of the first light source 18a.

[0035] The second image sensor 19b receives light reflected from the second surface of the document M. By receiving this light, the second image sensor 19b reads the second surface of the document M. The second image sensor 19b is configured to extend in the document width direction. The configuration of the second image sensor 19b may be the same as or different from that of the first image sensor 19a. It is preferable that the configuration of the second image sensor 19b is the same as that of the first image sensor 19a.

[0036] The second scanner 8b illuminates the second surface of the original document M with light from the second light source 18b, and the second image sensor 19b receives the light reflected from the second surface of the original document M. The second image sensor 19b reads the second surface of the original document M by receiving the light reflected from the second surface of the original document M.

[0037] The scanning unit 8 comprises a first scanner 8a and a second scanner 8b. The scanning unit 8 can scan both sides of the original document M. The scanning unit 8 may scan one side of the original document M using either the first scanner 8a or the second scanner 8b. The scanning unit 8 comprises, but is not limited to, the first scanner 8a and the second scanner 8b. The scanning unit 8 may consist of either the first scanner 8a or the second scanner 8b.

[0038] The ultrasonic sensor 9 detects double feeding of the document M being transported along the transport path 12. In the image scanner 1 shown in Figure 2, the ultrasonic sensor 9 is positioned between the second transport roller pair 14 and the third transport roller pair 15. The ultrasonic sensor 9 is positioned along the transport path 12. The ultrasonic sensor 9 is used as part of the transport mechanism 7. The ultrasonic sensor 9 comprises a transmitting unit 21 and a receiving unit 61. The transmitting unit 21 and the receiving unit 61 are positioned on either side of the transport path 12. The ultrasonic sensor 9 corresponds to an example of an ultrasonic device.

[0039] The transmitting unit 21 transmits ultrasonic waves. The transmitting unit 21 transmits ultrasonic waves toward the transport path 12. When ultrasonic waves are transmitted while the document M is being transported to a position opposite the transmitting unit 21, the ultrasonic waves pass through the document M and are transmitted to the receiving unit 61. As the ultrasonic waves pass through the document M, the sound pressure of the ultrasonic waves is attenuated. The transmitting unit 21 corresponds to an example of an ultrasonic transmitting unit.

[0040] The receiving unit 61 receives ultrasonic waves. The receiving unit 61 receives ultrasonic waves transmitted from the transmitting unit 21 and that have passed through the transport path 12. When ultrasonic waves are transmitted while the document M is being transported to a position opposite the transmitting unit 21, the receiving unit 61 receives the ultrasonic waves that have passed through the document M. The receiving unit 61 generates a received signal corresponding to the sound pressure of the ultrasonic waves. The receiving unit 61 transmits the generated received signal to the control unit 11. The receiving unit 61 corresponds to an example of an ultrasonic receiving unit.

[0041] The transmitting unit 21 and the receiving unit 61 are configured to be identical or substantially identical. The configurations of the transmitting unit 21 and the receiving unit 61 will be described later. The ultrasonic sensor 9 comprises a transmitting unit 21 and a receiving unit 61, but is not limited to this configuration. The transmitting unit 21 may also have the functions of the receiving unit 61. The transmitting unit 21 receives ultrasonic waves reflected from the document M. The transmitting unit 21 generates a received signal corresponding to the sound pressure of the received ultrasonic waves. The transmitting unit 21 transmits the generated received signal to the control unit 11. The transmitting unit 21 and the receiving unit 61 are not limited to the arrangement shown in Figure 2. The transmitting unit 21 may be placed in the position of the receiving unit 61 shown in Figure 2. In this case, the receiving unit 61 is placed in the position of the transmitting unit 21 shown in Figure 2.

[0042] The control unit 11 is a controller that performs various types of control. For example, the control unit 11 is a processor having a CPU (Central Processing Unit). The control unit 11 may consist of one or more processors. The control unit 11 may also have semiconductor memory such as RAM (Random Access Memory) or ROM (Read Only Memory). The semiconductor memory functions as the work area of ​​the control unit 11. The control unit 11 functions as various functional units by executing control programs stored in memory (not shown).

[0043] The control unit 11 controls the transport of the document M by the transport mechanism 7 by controlling the drive of the transport motor 17. The control unit 11 transports the document M along the transport path 12 by driving the transport motor 17. The control unit 11 controls the timing of starting the transport of the document M, the transport speed of the document M, the stop of the transport of the document M, etc.

[0044] The control unit 11 controls the reading of the document M by controlling the drive of the reading unit 8. The control unit 11 causes the reading unit 8 to read the document M by operating the reading unit 8. The control unit 11 controls the reading start timing, reading stop timing, single-sided / double-sided reading, etc., of the reading unit 8.

[0045] The control unit 11 receives the received signal output by the ultrasonic sensor 9. Based on the received signal, the control unit 11 detects a double feed of the document M. When a double feed is detected, the control unit 11 stops the transport of the document M. The control unit 11 stops the transport of the document M by controlling the transport mechanism 7.

[0046] The transport motor 17 generates driving force to drive the various drive rollers. The transport motor 17 transmits the generated driving force to the various drive rollers via a drive transmission mechanism (not shown). The transport motor 17 rotates the first drive roller 13a, the second drive roller 14a, the third drive roller 15a, and the fourth drive roller 16a.

[0047] Figure 3 shows a schematic configuration of the transmitting unit 21 of the ultrasonic sensor 9. The configuration of the transmitting unit 21 shown in Figure 3 may also be used as the configuration of the receiving unit 61. Figure 3 is a view of the transmitting unit 21 from the -Y direction. To make it easier to see the configuration of the transmitting unit 21, Figure 3 omits the +Y direction and -Y direction faces of the holder 31. The transmitting unit 21 comprises a circuit board 25, an ultrasonic array 27, a wiring shield 29, a holder 31, a filter 33, and a connector 35.

[0048] Several figures, including Figure 3, show the XYZ coordinate system. The Z axis is parallel to the direction in which ultrasound is transmitted from the ultrasound array 27. The +Z direction is the direction in which ultrasound is transmitted. The -Z direction is the opposite direction in which ultrasound is transmitted. The X axis is perpendicular to the Z axis. The X axis is parallel to the long side of the circuit board 25. The +X direction is the direction from left to right in Figure 3. The -X direction is the direction from right to left in Figure 3. The Y axis is perpendicular to the Z axis. The Y axis is parallel to the short side of the circuit board 25. The +Y direction is the direction from front to back in Figure 3. The -Y direction is the direction from back to front in Figure 3.

[0049] The circuit board 25 supports the ultrasonic array 27 and the wiring shield 29 in the +Z direction. The circuit board 25 may also support the holder 31 in the +Z direction. The circuit board 25 connects to the connector 35 in the -Z direction. The circuit board 25 is a rectangular plate member having a long side and a short side. The circuit board 25 supports the element wiring 37, etc., which will be described later, in the +Z direction.

[0050] The ultrasonic array 27 transmits ultrasound from the array aperture 27a. The array aperture 27a is a part of the plane of the ultrasonic array 27 in the +Z direction. The array aperture 27a corresponds to an example of a transmitting plane. Details of the array aperture 27a will be described later. The ultrasonic array 27 transmits ultrasound in a transmitting direction intersecting the array aperture 27a. The ultrasound transmitted by the ultrasonic array 27 is a sound wave with a frequency of 100 kHz to 800 kHz. The frequency of the transmitted ultrasound is adjusted as appropriate. When the configuration shown in Figure 3 is the receiving unit 61, the ultrasonic array 27 receives ultrasound. The ultrasonic array 27 corresponds to an example of an ultrasonic element.

[0051] The ultrasonic array 27 is positioned on the plane of the circuit board 25 in the +Z direction. The array aperture 27a of the ultrasonic array 27 is located at an array aperture height Ha relative to the plane of the circuit board 25 in the +Z direction.

[0052] The wiring shield 29 covers the element wiring 37 that is placed on the circuit board 25. The wiring shield 29 shields the element wiring 37 by covering it. The wiring shield 29 is placed on the plane of the circuit board 25 in the +Z direction. The wiring shield 29 is placed on the outer periphery of the ultrasonic array 27.

[0053] The wiring shield 29 has a wiring shield surface 29s. The wiring shield surface 29s is located at a wiring shield height Hs relative to the +Z direction plane of the circuit board 25. The wiring shield height Hs is higher than the array aperture height Ha. By providing the wiring shield surface 29s at the wiring shield height Hs, the wiring shield 29 functions as a protective cover to protect the ultrasonic array 27. When the transmitting unit 21 is assembled by an operator, the wiring shield 29 can reduce the operator's contact with the ultrasonic array 27. The wiring shield 29 corresponds to an example of a shielding member. The wiring shield height Hs is preferably close to the array aperture height Ha. When the wiring shield height Hs is low, noise from multiple reflection components by the wiring shield 29 is suppressed.

[0054] The holder 31 supports the filter 33. The holder 31 is positioned on the outer periphery of the wiring shield 29 on the circuit board 25. The holder 31 is configured to cover the outer periphery of the wiring shield 29. The holder 31 is configured separately from the wiring shield 29. The holder 31 is configured to extend in the direction of ultrasonic transmission. The holder 31 is configured to have a predetermined height in the +Z direction. The holder 31 is provided with a holder opening 31a. The holder opening 31a is provided at a position in the +Z direction facing the ultrasonic array 27. The holder 31 corresponds to an example of a retaining member. The holder opening 31a corresponds to an example of a retaining member opening. The outer periphery of the wiring shield 29 corresponds to an example of a shield outer periphery.

[0055] The filter 33 protects the ultrasonic array 27. The filter 33 is supported by the holder 31. The filter 33 is provided in the holder opening 31a. The filter 33 is configured to face the +Z direction plane of the ultrasonic array 27. The filter 33 is positioned opposite the array opening 27a of the ultrasonic array 27 in the direction of ultrasonic transmission. The filter 33 has holes that allow ultrasonic waves to pass through. Details of the filter 33 will be described later. The filter 33 corresponds to an example of a protective member.

[0056] The filter 33 is positioned at an angle with respect to the array aperture 27a of the ultrasonic array 27. By positioning the filter 33 at an angle with respect to the array aperture 27a of the ultrasonic array 27, noise caused by multiple reflection components of ultrasound originating from the filter 33 is suppressed.

[0057] The filter 33 is positioned at a filter height Hf along the Z-axis from the center of the array aperture 27a of the ultrasonic array 27. The filter height Hf can be appropriately set by the shape of the holder 31. When ultrasonic waves are transmitted from the ultrasonic array 27, noise is generated due to multiple reflection components caused by the filter 33. If the filter height Hf is lower than a predetermined height, noise due to multiple reflection components caused by the filter 33 is superimposed on the received signal. The received signal is the signal received by the receiving unit 61. The noise due to multiple reflection components caused by the filter 33 reduces the accuracy of the received signal. If the filter height Hf is higher than a predetermined height, the received signal and the noise due to multiple reflection components caused by the filter are separated. The reduction in the accuracy of the received signal is suppressed. Since the filter height Hf can be appropriately set by the shape of the holder 31, noise due to multiple reflection components caused by the filter 33 can be separated from the received signal. The reduction in the accuracy of the received signal is suppressed.

[0058] The connector 35 is configured to allow the transmission unit 21 to be connected to the image scanner 1. The connector 35 is connected to the circuit board 25 on the -Z plane of the circuit board 25. The connector 35 transmits control signals and the like transmitted from the control unit 11 to the ultrasonic array 27. The connector 35 supplies power to the ultrasonic array 27 from a power supply (not shown). The connector 35 transmits the signals generated by the ultrasonic array 27 to the control unit 11.

[0059] Figure 4 shows a schematic configuration of the transmitting unit 21. Figure 4 is a view of the transmitting unit 21 from the +Z direction. The configuration of the transmitting unit 21 shown in Figure 4 may also be used as the configuration of the receiving unit 61. Figure 4 shows the unit without the filter 33.

[0060] The holder 31 covers the +Z direction surface of the circuit board 25. The holder opening 31a provided in the holder 31 is configured to allow the array opening 27a to be visible from the +Z direction. The shape of the holder opening 31a shown in Figure 4 is rectangular, but is not limited to this. As long as ultrasonic waves can pass through the holder opening 31a, its shape is not limited. The holder opening 31a is provided at a position opposite the array opening 27a along the +Z axis. The holder opening 31a shown in Figure 4 is an opening with a width Wh along the X and Y axes.

[0061] The ultrasonic array 27 has an array aperture 27a that transmits ultrasonic waves in the +Z direction plane. The array aperture 27a shown in Figure 4 is an aperture with an array aperture width Wa along the X and Y axes. The array aperture width Wa is shorter than the holder aperture width Wh. The holder aperture 31a is configured to be wider than the array aperture 27a. By configuring the holder aperture 31a to be wider than the array aperture 27a, noise due to multiple reflection components originating from the holder 31 is reduced.

[0062] The wiring shield 29 is provided with a wiring shield opening 29a. The wiring shield opening 29a corresponds to an example of a shield opening. The wiring shield opening 29a is located opposite the array opening 27a along the +Z axis. The wiring shield opening 29a shown in Figure 4 is an opening with a width Ws along the X and Y axes. The wiring shield opening width Ws is wider than the array opening width Wa. The wiring shield opening 29a is configured to be wider than the array opening 27a. By configuring the wiring shield opening 29a to be wider than the array opening 27a, noise due to multiple reflection components caused by the wiring shield 29 is reduced.

[0063] The wiring shield opening 29a is positioned opposite the holder opening 31a along the +Z axis. The wiring shield opening width Ws is narrower than the holder opening width Wh. The holder opening 31a is wider than the wiring shield opening 29a. By making the holder opening 31a wider than the wiring shield opening 29a, noise caused by multiple reflection components originating from the holder 31 is reduced.

[0064] The holder opening 31a is wider than the array opening 27a and the wiring shield opening 29a. Noise caused by multiple reflection components originating from the holder 31, and noise caused by multiple reflection components originating from the wiring shield 29, are suppressed.

[0065] Figure 5 shows the relationship between the ultrasonic array 27 and the wiring shield 29. Figure 5 omits the holder 31. Figure 5 shows a perspective view of the transmitting unit 21 excluding the holder 31.

[0066] The circuit board 25 has a first hole 25a. The first hole 25a is a hole that goes through the circuit board 25. The first hole 25a is used when the transmitting unit 21 is attached to the image scanner 1.

[0067] The wiring shield 29 is positioned around the outer circumference of the array opening 27a of the ultrasonic array 27. The wiring shield surface 29s of the wiring shield 29 is positioned in the +Z direction relative to the array opening 27a. The wiring shield surface 29s is positioned in the transmission direction relative to the array opening 27a. The wiring shield opening width Ws is configured to be such that it is difficult for the fingers or tools of an operator assembling the transmitting unit 21 to enter. The wiring shield opening width Ws is configured to be several centimeters. The wiring shield 29 functions as a protective cover during assembly.

[0068] The wiring shield 29 is positioned in the transmission direction relative to the array aperture 27a. The wiring shield aperture 29a is wider than the array aperture 27a. The wiring shield 29 functions as a protective cover to prevent workers or tools from coming into contact with the ultrasonic array 27 during the assembly of the transmitting unit 21. By configuring the wiring shield opening 29a to be wider than the array opening 27a, noise caused by multiple reflection components originating from the wiring shield 29 is suppressed.

[0069] Figure 6 shows the schematic configuration of the circuit board 25. Figure 6 shows the state with the holder 31, wiring shield 29, and ultrasonic array 27 removed. Figure 6 shows the element wiring 37 arranged on the circuit board 25. The element wiring 37 is covered by the wiring shield 29.

[0070] The element wiring 37 supplies power or signals to the ultrasonic array 27. The element wiring 37 is arranged on the outer periphery of the array aperture 27a. The element wiring 37 is wiring that connects to the ultrasonic array 27. The element wiring 37 comprises a first element wiring 37a, a second element wiring 37b, and a third element wiring 37c. The element wiring 37 corresponds to an example of wiring.

[0071] The first element wiring 37a transmits a control signal to the ultrasonic array 27. The control signal is transmitted from the control unit 11 to the ultrasonic array 27. The control signal is a signal that controls the operation of the ultrasonic array 27. The second element wiring 37b is a ground wire. The third element wiring 37c is a through-hole. The connector 35 and the ultrasonic array 27 are connected via the third element wiring 37c. The first element wiring 37a, the second element wiring 37b, and the third element wiring 37c are shielded by the wiring shield 29.

[0072] Figure 7 shows a schematic configuration of the array aperture 27a. Figure 7 shows a magnified view of a portion of the array aperture 27a. When the ultrasonic array 27 is placed in the transmitting unit 21, the array aperture 27a transmits ultrasonic waves. When the ultrasonic array 27 is placed in the receiving unit 61, the array aperture 27a receives ultrasonic waves. The array aperture 27a comprises an element substrate 41 and a piezoelectric element 43. The element substrate 41 and the piezoelectric element 43 are arranged along the Z-axis.

[0073] The element substrate 41 transmits or receives ultrasonic waves. The surface of the element substrate 41 in the +Z direction functions as either a transmitting section 21a or a receiving section 61a. The transmitting section 21a is the part of the transmitting unit 21 that transmits ultrasonic waves. The receiving section 61a is the part of the receiving unit 61 that receives ultrasonic waves. The element substrate 41 has a substrate body 45 and a diaphragm 47. The substrate body 45 and the diaphragm 47 are arranged along the Z axis. The diaphragm 47 is positioned in the -Z direction of the substrate body 45.

[0074] The substrate body 45 is made of a semiconductor substrate such as Si. The substrate body 45 supports a diaphragm 47 which is positioned in the -Z direction. The substrate body 45 has a plurality of openings 45a and partition walls 45b.

[0075] Multiple openings 45a are provided along the X and Y axes. The openings 45a penetrate the main body portion 45 of the substrate. The multiple openings 45a are separated by partition walls 45b. The openings 45a open in the +Z direction. The -Z direction surface of the openings 45a is composed of a diaphragm 47. The openings 45a expose the diaphragm 47.

[0076] The partition wall 45b divides the multiple openings 45a. The partition wall 45b supports the diaphragm 47. The partition wall 45b is a member that extends along the X-axis and the Y-axis. The partition wall 45b is constructed to a predetermined height along the Z-axis.

[0077] The diaphragm 47 transmits or receives ultrasonic waves by vibrating. The diaphragm 47 is positioned in the -Z direction of the substrate body 45. The diaphragm 47 is made of a laminate of SiO2 and ZrO2, etc. The diaphragm 47 is supported by the partition wall 45b of the substrate body 45. The vibrating surface 47a, which is the +Z direction surface of the diaphragm 47, constitutes the -Z direction surface of the opening 45a.

[0078] The piezoelectric element 43 vibrates the diaphragm 47 to transmit ultrasonic waves. Alternatively, the piezoelectric element 43 converts vibrations into a signal when the diaphragm 47 receives ultrasonic waves and vibrates. Multiple piezoelectric elements 43 are provided on the -Z direction surface of the diaphragm 47. The piezoelectric elements 43 are positioned in the -Z direction of the opening 45a. The piezoelectric element 43 has a first electrode 49, a piezoelectric film 51, and a second electrode 53. The first electrode 49 is positioned on the -Z direction surface of the diaphragm 47. The first electrode 49, the piezoelectric film 51, and the second electrode 53 are stacked in this order on the -Z direction surface of the diaphragm 47. The diaphragm 47 and one piezoelectric element 43 constitute an ultrasonic transducer 55.

[0079] The ultrasonic transducer 55 converts an electrical signal into ultrasound, or converts ultrasound into an electrical signal. When the ultrasonic array 27 having an array aperture 27a is provided in the transmitting unit 21, the ultrasonic transducer 55 converts an electrical signal into ultrasound and transmits the ultrasound. When the ultrasonic array 27 having an array aperture 27a is provided in the receiving unit 61, the ultrasonic transducer 55 receives the ultrasound and converts the ultrasound into an electrical signal. The array aperture 27a is formed by arranging multiple ultrasonic transducers 55 in a two-dimensional array structure.

[0080] The first electrode 49 is a common electrode connected to multiple piezoelectric elements 43. The first electrode 49 is provided on the -Z direction surface of the diaphragm 47. The first electrode 49 transmits an electrical signal to the piezoelectric film 51 of the multiple piezoelectric elements 43. Alternatively, the first electrode 49 receives an electrical signal from the piezoelectric film 51 of the multiple piezoelectric elements 43.

[0081] The piezoelectric film 51 expands and contracts in response to an electrical signal. The piezoelectric element 43 expands and contracts when a pulse wave voltage of a predetermined frequency is applied between the first electrode 49 and the second electrode 53. Due to the expansion and contraction of the piezoelectric film 51, the vibrating surface 47a vibrates at a frequency corresponding to the opening width of the opening 45a, etc. The ultrasonic transducer 55 transmits ultrasonic waves in the +Z direction. The piezoelectric film 51 transmits ultrasonic waves by expanding and contracting.

[0082] Alternatively, the piezoelectric film 51 expands and contracts when it receives ultrasonic waves. By expanding and contracting, the piezoelectric film 51 converts ultrasonic waves into electrical signals. The ultrasonic transducer 55 receives ultrasonic waves transmitted in the -Z direction. When the diaphragm 47 receives ultrasonic waves, the piezoelectric film 51 vibrates. When the piezoelectric film 51 vibrates, a potential difference is generated between the first electrode 49 and the second electrode 53. The piezoelectric element 43 generates an electrical signal corresponding to the potential difference. The generated electrical signal is output to the control unit 11 as a received signal.

[0083] Figure 8 shows the output distribution of ultrasound transmitted from the ultrasound array 27. Figure 8 also shows the directivity of the ultrasound. The horizontal axis of Figure 8 represents the transmission angle θ of ultrasound transmitted through the center of the array aperture 27a and parallel to the Z-axis, with 0° being the transmission angle θ. The angles shown on the horizontal axis represent the transmission angle θ of ultrasound transmitted through the center of the array aperture 27a with respect to an axis parallel to the Z-axis. A + sign in the angle indicates the +X direction, as an example. A - sign in the angle indicates the -X direction. The vertical axis of Figure 8 represents the intensity of the ultrasound. The vertical axis is normalized to 1.0, representing the intensity of ultrasound transmitted at a transmission angle θ of 0°.

[0084] Figure 8 shows the power distribution curve 71 transmitted by the ultrasonic array 27. The power distribution curve 71 shows that the intensity of the ultrasound differs depending on the transmission angle θ. The ultrasound transmitted by the ultrasonic array 27 has strong directivity when the transmission angle θ is 0°. The ultrasound transmitted by the ultrasonic array 27 has directivity in the +Z direction. The power distribution curve 71 shows the main lobe 71a and the side lobes 71b.

[0085] Main lobe 71a represents the main peak of the ultrasound. Main lobe 71a is a peak centered at a transmission angle of 0°. Main lobe 71a indicates that the ultrasound intensity is highest at a transmission angle θ of 0°.

[0086] The side lobe 71b shows the second highest ultrasonic intensity peak after the main lobe 71a. The side lobe 71b occurs at a wider transmission angle θ than the main lobe 71a. The side lobe 71b is a source of noise.

[0087] Figure 8 shows the side lobe half-value 73, which represents the half-value of the peak intensity of side lobe 71b. In Figure 8, the side lobe half-value angles θs that result in side lobe half-value 73 are +50° and -50°. Side lobe half-value 73 can be appropriately calculated based on the structure of the array aperture 27a.

[0088] Figure 9 shows the relationship between the ultrasonic array 27 and the wiring shield 29. Figure 9 shows the positional relationship between the ultrasonic array 27 and the wiring shield opening 29a. Figure 9 shows the vertical line VL, the virtual line EL, the edge angle θe, and the distance between members ds.

[0089] The vertical line VL is a perpendicular line passing through the center of the array aperture 27a. The vertical line VL corresponds to the position of transmission angle 0° shown in Figure 8.

[0090] The virtual line EL is a virtual line connecting the center of the array opening 27a and the end of the wiring shield opening 29e. The end of the wiring shield opening 29e is the end of the wiring shield opening 29a. The end of the wiring shield opening 29e is the end of the +Z direction face of the wiring shield 29.

[0091] The edge angle θe is the angle between the virtual line EL and the vertical line VL. The edge angle θe corresponds to the ultrasonic transmission angle θ. Ultrasonic waves with a transmission angle θ smaller than the edge angle θe pass through the wiring shield opening 29a. Ultrasonic waves with a transmission angle θ larger than the edge angle θe are reflected by the -Z plane of the wiring shield 29. The reflected ultrasonic waves become noise, reducing the sensitivity of the ultrasonic sensor 9.

[0092] The edge angle θe is preferably wider than the side lobe half-power angle θs. When the edge angle θe is wider than the side lobe half-power angle θs, the intensity of the ultrasound reflected from the -Z direction plane of the wiring shield 29 decreases. When the intensity of the ultrasound decreases, the effect of noise is reduced. The ultrasonic sensor 9 can suppress the decrease in measurement accuracy due to the effect of noise.

[0093] The inter-member distance ds is the distance between the +Z-direction plane of the ultrasonic array 27 and the +Z-direction plane of the wiring shield 29. When the inter-member distance ds is shortened, the edge angle θe increases, and the reflection of ultrasonic waves from the -Z-direction plane of the wiring shield 29 decreases. When the inter-member distance ds is lengthened, contact with the ultrasonic array 27 by the worker is reduced. The wiring shield opening width Ws of the wiring shield opening 29a is 2 × ds × tanθe. The wiring shield opening width Ws is preferably given by the following formula (1). Ws≧2×ds×tanθs…(1) When the wiring shield aperture width Ws satisfies the relationship given in equation (1), the intensity of the ultrasonic waves reflected from the -Z direction plane of the wiring shield 29 decreases. As the ultrasonic intensity decreases, the effect of noise is reduced. The ultrasonic sensor 9 can suppress the decrease in measurement accuracy due to the effect of noise.

[0094] The edge angle θe between the imaginary line EL connecting the wiring shield opening end 29e, which is the end of the wiring shield opening 29a, and the center of the array opening 27a, and the vertical line VL of the array opening 27a passing through the center of the array opening 27a, is preferably wider than the side lobe half-power angle θs, which is the half-power of the side lobe 71b of the ultrasonic waves transmitted from the array opening 27a. Reflection from the ultrasonic wiring shield 29, which forms the side lobe 71b, is suppressed. The ultrasonic sensor 9 can minimize the decrease in detection accuracy.

[0095] Figure 10 shows a schematic configuration of the filter 33. Figure 10 shows a magnified view of the filter 33. Figure 10 shows the first direction D1 and the second direction D2. The first direction D1 and the second direction D2 are orthogonal to each other. The filter 33 has a plurality of first wires 33a and a plurality of second wires 33b.

[0096] The first wire 33a extends along the second direction D2. The first wire 33a is a member with a wire diameter W1. Multiple first wires 33a are arranged along the first direction D1. Multiple first wires 33a are arranged at a pitch W3.

[0097] The second wire 33b extends along the first direction D1. The second wire 33b is a member with a wire diameter W1. Multiple second wires 33b are arranged along the second direction D2. Multiple second wires 33b are arranged at a pitch W3.

[0098] The first wire 33a and the second wire 33b are made of members with a wire diameter W1, but are not limited to this. The first wire 33a and the second wire 33b may each be made of members with different diameters. The multiple first wires 33a and the multiple second wires 33b are arranged at a pitch W3, but are not limited to this. The spacing between the multiple first wires 33a and the spacing between the multiple second wires 33b may be different.

[0099] The wire diameters W1 of the first wire 33a and the second wire 33b are preferably less than the wavelength of the ultrasound. By setting the wire diameter W1 to be less than the wavelength of the ultrasound, diffuse reflection of the ultrasound by the first wire 33a and the second wire 33b is suppressed.

[0100] The first wire 33a and the second wire 33b are made of metal materials such as copper, iron, brass, and SUS, or alloy materials, or synthetic resins such as nylon and polyester. Preferably, the first wire 33a and the second wire 33b are made of conductive materials. The first wire 33a and the second wire 33b can be made resistant to static electricity and electromagnetic waves.

[0101] The filter 33 is constructed as a mesh of first wires 33a and second wires 33b. The first wires 33a and second wires 33b are configured to intersect at 90°, but are not limited to this. The first wires 33a and second wires 33b may be arranged to intersect at angles other than 90°.

[0102] The filter opening 34 is formed by a first wire 33a and a second wire 33b. The filter opening 34 is formed by adjacent first wires 33a and adjacent second wires 33b. The filter opening 34 is composed of an opening W2. The opening W2 is the distance between adjacent first wires 33a. The opening W2 is the distance between adjacent second wires 33b. The opening W2 is preferably 1 mm or less. When the opening W2 is set to 1 mm or less, the possibility of foreign matter adhering to the ultrasonic array 27 is reduced. The filter opening 34 allows ultrasonic waves to pass through. The filter opening 34 corresponds to an example of a hole.

[0103] The porosity S of filter 33 is calculated by the following equation (2). S = 100 × (W2 / W3) 2 …(2) The porosity S is preferably 20% or more. The porosity S represents the area ratio of the filter opening 34 in the filter 33. When the porosity S is less than 20%, the sound transmission rate of the filter 33 is less than 50%. Sound transmission rate is the percentage of sound waves that pass through the filter 33. When the sound transmission rate is less than 50%, the detection sensitivity of the ultrasonic sensor 9 decreases. The ultrasonic sensor 9 becomes less able to detect double feeding of the document M occurring in the image scanner 1. When the porosity S is 20% or more, the sound transmission rate of the filter 33 is 50% or more. The filter 33 can suppress an excessive decrease in sound pressure, and the decrease in sensitivity of the ultrasonic sensor 9 for double feeding detection is suppressed.

[0104] The ultrasonic sensor 9 comprises an ultrasonic array 27 having an array aperture 27a for transmitting ultrasonic waves and transmitting ultrasonic waves in a transmission direction intersecting the array aperture 27a; element wiring 37 arranged on the outer periphery of the array aperture 27a and connected to the ultrasonic array 27; a wiring shield 29 covering the element wiring 37; a holder 31 arranged on the outer periphery of the wiring shield 29 and extending in the transmission direction; and a filter 33 facing the array aperture 27a and having a filter aperture 34 for passing ultrasonic waves. The wiring shield 29 is provided with a wiring shield aperture 29a facing the array aperture 27a. The holder 31 is provided with a holder aperture 31a facing the array aperture 27a. The filter 33 is positioned in the holder aperture 31a. By positioning the filter 33 on the holder 31, the distance between the wiring shield 29 and the ultrasonic array 27, and the position of the filter 33 can be set individually. This makes it possible to design an ultrasonic sensor 9 that is less susceptible to noise caused by multiple reflection components of ultrasonic waves due to the holder 31 and noise caused by multiple reflection components of ultrasonic waves due to the wiring shield 29, thereby suppressing a decrease in detection accuracy.

[0105] First Embodiment The first embodiment shows an image scanner 1 on which an ultrasonic sensor 9 is mounted, including a transmitting unit 21 and a receiving unit 61, both configured as shown in Figure 3. Figure 11 shows a schematic configuration around the ultrasonic sensor 9. Figure 11 shows an enlarged view of the ultrasonic sensor 9 and the transport path 12 shown in Figure 2. Figure 11 shows the transport path 12 horizontally. Figure 11 shows the ultrasonic sensor 9, the transport path 12, the first sensor support member 81, and the second sensor support member 83.

[0106] The ultrasonic sensor 9 comprises a transmitting unit 21 and a receiving unit 61. The transmitting unit 21 and the receiving unit 61 are positioned opposite each other across the transport path 12. The transmitting unit 21 and the receiving unit 61 are positioned at an inclination with respect to the transport path 12. By positioning the transmitting unit 21 and the receiving unit 61 at an inclination with respect to the transport path 12, the influence of noise can be reduced.

[0107] The transmitting unit 21 comprises a circuit board 25, an ultrasonic array 27, a wiring shield 29, a holder 31, and a filter 33. The ultrasonic array 27 of the transmitting unit 21 is positioned away from the transport path 12. The array aperture 27a of the ultrasonic array 27 transmits ultrasonic waves. The transmitting unit 21 is positioned at an angle to the transport path 12. A vertical line VL passing through the center of the ultrasonic array 27 of the transmitting unit 21 intersects the transport path 12 at an angle different from 90°.

[0108] The receiving unit 61 comprises a circuit board 25, an ultrasonic array 27, a wiring shield 29, a holder 31, and a filter 33. The ultrasonic array 27, wiring shield 29, holder 31, and filter 33 of the receiving unit 61 correspond to examples of a second ultrasonic element, a second shielding member, a second holding member, and a second protective member, respectively.

[0109] The ultrasonic array 27 of the receiving unit 61 has an array aperture 27a for receiving ultrasonic waves. The array aperture 27a of the receiving unit 61 corresponds to an example of a receiving surface. The ultrasonic array 27 of the receiving unit 61 is positioned away from the transport path 12 relative to the holder 31 of the receiving unit 61.

[0110] The circuit board 25 of the receiving unit 61 is positioned on the outer periphery of the array opening 27a of the receiving unit 61 and has element wiring 37 that connects to the ultrasonic array 27. The element wiring 37 provided on the circuit board 25 of the receiving unit 61 corresponds to an example of second wiring. The outer periphery of the array opening 27a of the receiving unit 61 corresponds to an example of the outer periphery of the receiving surface.

[0111] The wiring shield 29 of the receiving unit 61 covers the element wiring 37 arranged on the circuit board 25 of the receiving unit 61. The wiring shield 29 of the receiving unit 61 is provided with a wiring shield opening 29a at a position opposite to the array opening 27a of the receiving unit 61. The wiring shield opening 29a of the receiving unit 61 corresponds to an example of a second shield opening.

[0112] The holder 31 of the receiving unit 61 is positioned opposite the holder 31 of the transmitting unit 21, across the transport path 12. The holder 31 of the receiving unit 61 is provided with a holder opening 31a positioned opposite the array opening 27a of the transmitting unit 21. The holder opening 31a of the receiving unit 61 corresponds to an example of a second holding member opening.

[0113] The filter 33 of the receiving unit 61 is positioned opposite the array opening 27a of the receiving unit 61. The filter 33 of the receiving unit 61 allows the ultrasonic waves transmitted from the transmitting unit 21 to pass through. The filter 33 of the receiving unit 61 is located in the holder opening 31a of the receiving unit 61.

[0114] The receiving unit 61 is positioned at an angle to the transport path 12. The vertical line VL passing through the center of the ultrasonic array 27 of the receiving unit 61 intersects the transport path 12 at an angle different from 90°.

[0115] The transport path 12 is formed by a first transport guide 85 and a second transport guide 87. The document M moves within the transport path 12 between the first transport guide 85 and the second transport guide 87. The first transport guide 85 is located on the side of the transmitting unit 21. The second transport guide 87 is located on the side of the receiving unit 61.

[0116] The first transport guide 85 is provided with a first transport guide opening 85a. The first transport guide opening 85a allows ultrasonic waves transmitted from the transmitting unit 21 to pass through. The first transport guide opening 85a is positioned opposite the array opening 27a of the transmitting unit 21. The shape of the first transport guide opening 85a is formed as a square, a circle, or the like. The size of the first transport guide opening 85a is larger than the size of the holder opening 31a of the transmitting unit 21. By making the first transport guide opening 85a larger than the holder opening 31a, the generation of noise due to the reflection of ultrasonic waves in the first transport guide 85 is suppressed.

[0117] The second transport guide 87 is provided with a second transport guide opening 87a. The second transport guide opening 87a allows ultrasonic waves transmitted from the transmitting unit 21 to pass through. The second transport guide opening 87a is positioned opposite the array opening 27a of the receiving unit 61. The shape of the second transport guide opening 87a is formed as a square, a circle, or the like. The size of the second transport guide opening 87a is larger than the size of the holder opening 31a of the receiving unit 61. By making the second transport guide opening 87a larger than the holder opening 31a, the generation of noise due to the reflection of ultrasonic waves in the second transport guide 87 is suppressed.

[0118] The first sensor support member 81 supports the transmission unit 21. The first sensor support member 81 may be the housing of the image scanner 1, or a member supported by the housing. The first sensor support member 81 supports the transmission unit 21 in an inclined position with respect to the transport path 12.

[0119] The second sensor support member 83 supports the receiving unit 61. The second sensor support member 83 may be the housing of the image scanner 1, or a member supported by the housing. The second sensor support member 83 supports the receiving unit 61 in an inclined position with respect to the transport path 12.

[0120] The arrangement of the transmitting unit 21 and the receiving unit 61 is not limited to the arrangement shown in Figure 11. The transmitting unit 21 may be positioned on the side of the second transport guide 87, and the receiving unit 61 may be positioned on the side of the first transport guide 85.

[0121] The image scanner 1 that transports the original document M includes a transport path 12 for transporting the original document M, a holder 31 having a holder opening 31a, an ultrasonic array 27 positioned away from the transport path 12 relative to the holder 31 and transmitting ultrasonic waves, element wiring 37 positioned on the outer periphery of the array opening 27a of the ultrasonic array 27 and connected to the ultrasonic array 27, a wiring shield 29 covering the element wiring 37, and a filter 33 facing the array opening 27a of the ultrasonic array 27 and having a filter opening 34 that allows ultrasonic waves to pass through. The wiring shield 29 is provided with a wiring shield opening 29a facing the array opening 27a. The holder opening 31a faces the array opening 27a. The filter 33 is positioned in the holder opening 31a. By placing the filter 33 in the holder 31, the distance between the wiring shield 29 and the ultrasonic array 27, and the position of the filter 33 can be set individually. This makes it possible to design an image scanner 1 equipped with an ultrasonic sensor 9 that is less susceptible to noise caused by multiple reflection components of ultrasonic waves due to the holder 31 and noise caused by multiple reflection components of ultrasonic waves due to the wiring shield 29, thereby suppressing a decrease in detection accuracy.

[0122] The receiving unit 61 of the image scanner 1 comprises a holder 31 facing the holder 31 of the transmitting unit 21, an ultrasonic array 27 positioned away from the transport path 12 relative to the holder 31 and having an array aperture 27a for receiving ultrasonic waves, element wiring 37 arranged on the outer periphery of the array aperture 27a and connected to the ultrasonic array 27, a wiring shield 29 covering the element wiring 37, and a filter 33 facing the array aperture 27a of the ultrasonic array 27 and allowing ultrasonic waves to pass through. The wiring shield 29 of the receiving unit 61 is provided with a wiring shield aperture 29a facing the array aperture 27a of the receiving unit 61. The holder 31 of the receiving unit 61 is provided with a holder aperture 31a facing the array aperture 27a of the receiving unit 61. The filter 33 of the receiving unit 61 is positioned in the holder aperture 31a of the receiving unit 61. By positioning the filter 33 of the receiving unit 61 in the holder opening 31a of the receiving unit 61, it becomes possible to design an image scanner 1 that suppresses noise generated in the receiving unit 61.

[0123] Second Embodiment The second embodiment shows an image scanner 1 in which the first transport guide 85 functions as a holder 31 for the transmitting unit 21 in the configuration shown in Figure 3. The second embodiment shows an image scanner 1 in which the second transport guide 87 functions as a holder 31 for the receiving unit 61 in the configuration shown in Figure 3. Figure 12 shows a schematic configuration around the ultrasonic sensor 9. Figure 12 shows a configuration in which the first transport guide 85 supports the filter 33 of the transmitting unit 21. Figure 12 shows a configuration in which the second transport guide 87 supports the filter 33 of the receiving unit 61. Figure 12 shows the ultrasonic sensor 9, the transport path 12, the first sensor support member 81, and the second sensor support member 83.

[0124] The ultrasonic sensor 9 comprises a transmitting unit 21 and a receiving unit 61. The transmitting unit 21 and the receiving unit 61 are positioned opposite each other across the transport path 12. The transmitting unit 21 and the receiving unit 61 are positioned at an angle with respect to the transport path 12. By positioning the transmitting unit 21 and the receiving unit 61 at an angle with respect to the transport path 12, the influence of noise can be reduced.

[0125] The transmitting unit 21 consists of a circuit board 25, an ultrasonic array 27, a wiring shield 29, and a part of the first transport guide 85. The circuit board 25, ultrasonic array 27, and wiring shield 29 have the same configuration as the circuit board 25, ultrasonic array 27, and wiring shield 29 shown in Figure 3, etc. The ultrasonic array 27 of the transmitting unit 21 is positioned away from the transport path 12. The array aperture 27a of the ultrasonic array 27 transmits ultrasonic waves. The transmitting unit 21 is positioned at an angle with respect to the transport path 12. The vertical line VL passing through the center of the ultrasonic array 27 of the transmitting unit 21 intersects the transport path 12 at an angle different from 90°.

[0126] The first transport guide 85 functions as a holder 31 for the transmitting unit 21 shown in Figure 3. The first transport guide 85 is provided with a first transport guide opening 85a at a position opposite to the array opening 27a of the ultrasonic array 27. The first transport guide opening 85a has the same function as the holder opening 31a. The first transport guide opening 85a is provided at a position opposite to the array opening 27a. The first transport guide opening 85a supports the filter 33. The first transport guide 85 corresponds to an example of a retaining member. The first transport guide opening 85a corresponds to an example of a retaining member opening.

[0127] The receiving unit 61 consists of a circuit board 25, an ultrasonic array 27, a wiring shield 29, and a part of the second transport guide 87. The circuit board 25, ultrasonic array 27, and wiring shield 29 have the same configuration as the circuit board 25, ultrasonic array 27, and wiring shield 29 shown in Figure 3, etc. The ultrasonic array 27, wiring shield 29, and filter 33 of the receiving unit 61 correspond to examples of a second ultrasonic element, a second shielding member, and a second protective member, respectively. The ultrasonic array 27, wiring shield 29, and filter 33 of the receiving unit 61 have the same configuration as the ultrasonic array 27, wiring shield 29, and filter 33 of the receiving unit 61 of the first embodiment.

[0128] The second transport guide 87 functions as a holder 31 for the receiving unit 61 shown in Figure 11. The second transport guide 87 has a second transport guide opening 87a positioned opposite the array opening 27a of the receiving unit 61. The second transport guide opening 87a has the same function as the holder opening 31a of the receiving unit 61. The second transport guide opening 87a is positioned opposite the array opening 27a of the receiving unit 61. The second transport guide opening 87a supports the filter 33 of the receiving unit 61. The second transport guide 87 corresponds to an example of a second retaining member. The second transport guide opening 87a corresponds to an example of a second retaining member opening.

[0129] The first transport guide 85 and the second transport guide 87 form a transport path 12. The first transport guide 85 and the second transport guide 87 have a guiding function for guiding the document M and a function for supporting the filter 33.

[0130] The image scanner 1 that transports the original document M includes a transport path 12 for transporting the original document M, a first transport guide 85 having a first transport guide opening 85a, an ultrasonic array 27 positioned away from the transport path 12 relative to the first transport guide 85 and transmitting ultrasonic waves, element wiring 37 positioned on the outer periphery of the array opening 27a of the ultrasonic array 27 and connected to the ultrasonic array 27, a wiring shield 29 covering the element wiring 37, and a filter 33 facing the array opening 27a of the ultrasonic array 27 and having a filter opening 34 that allows ultrasonic waves to pass through. The wiring shield 29 is provided with a wiring shield opening 29a facing the array opening 27a. The first transport guide opening 85a faces the array opening 27a. The filter 33 is positioned in the first transport guide opening 85a. By positioning the filter 33 in the first transport guide opening 85a, the distance between the wiring shield 29 and the ultrasonic array 27, and the position of the filter 33 can be set individually. This makes it possible to design an image scanner 1 equipped with an ultrasonic sensor 9 that is less susceptible to noise caused by multiple reflection components of ultrasonic waves originating from the first transport guide 85 and noise caused by multiple reflection components of ultrasonic waves originating from the wiring shield 29, thereby suppressing a decrease in detection accuracy.

[0131] The receiving unit 61 of the image scanner 1 includes a second transport guide 87 facing the first transport guide 85 of the transmitting unit 21, an ultrasonic array 27 positioned away from the transport path 12 relative to the second transport guide 87 and having an array aperture 27a for receiving ultrasonic waves, element wiring 37 positioned on the outer periphery of the array aperture 27a and connected to the ultrasonic array 27, a wiring shield 29 covering the element wiring 37, and a filter 33 facing the array aperture 27a of the ultrasonic array 27 and allowing ultrasonic waves to pass through. The wiring shield 29 of the receiving unit 61 is provided with a wiring shield aperture 29a facing the array aperture 27a of the receiving unit 61. The second transport guide 87 of the receiving unit 61 is provided with a second transport guide aperture 87a facing the array aperture 27a of the receiving unit 61. The filter 33 of the receiving unit 61 is positioned at the second transport guide aperture 87a. By positioning the filter 33 of the receiving unit 61 in the second transport guide opening 87a, it becomes possible to design an image scanner 1 that suppresses noise generated in the receiving unit 61. [Explanation of symbols]

[0132] 1…Image scanner, 2…Outer casing, 3…Document support, 4…Feed port, 5…Outlet, 7…Conveyor mechanism, 8…Reading unit, 8a…First scanner, 8b…Second scanner, 9…Ultrasonic sensor, 11…Control unit, 12…Conveyor path, 13…First transport roller pair, 13a…First drive roller, 13b…First driven roller, 14…Second transport roller pair, 14a…Second drive roller, 14b…Second driven roller, 15…Third transport roller pair, 15a…Third drive roller, 15b…Third driven roller, 16…Fourth transport roller - Pair, 16a...4th drive roller, 16b...4th driven roller, 17...transport motor, 18a...1st light source, 18b...2nd light source, 19a...1st image sensor, 19b...2nd image sensor, 21...transmitting unit, 21a...transmitting section, 25...circuit board, 25a...1st hole, 27...ultrasonic array, 27a...array opening, 29...wiring shield, 29a...wiring shield opening, 29e...wiring shield opening end, 29s...wiring shield surface, 31...holder, 31a...holder opening, 33...filter, 33a...1st wire, 33b ...Second wire, 34...Filter opening, 35...Connector, 37...Element wiring, 37a...First element wiring, 37b...Second element wiring, 37c...Third element wiring, 41...Element substrate, 43...Piezoelectric element, 45...Substrate body, 45a...Opening, 45b...Partition, 47...Diaphragm, 47a...Vibrating surface, 49...First electrode, 51...Piezoelectric film, 53...Second electrode, 55...Ultrasonic transducer, 61...Receiving unit, 61a...Receiving section, 71...Output distribution curve, 71a...Main lobe, 71b...Side lobe, 73...Side lobe half-value, 81...First sensor - Support member, 83... Second sensor support member, 85... First transport guide, 85a... First transport guide opening, 87... Second transport guide, 87a... Second transport guide opening, D1... First direction, D2... Second direction, ds... Distance between members, Ha... Array opening height, Hf... Filter height, Hs... Wiring shield height, M... Original document, S... Void ratio, T... Transport direction, Wa... Array opening width, Wh... Holder opening width, Ws... Wiring shield opening width, θ... Transmission angle, θe... Edge angle, θs... Side lobe half-power angle, W1... Wire diameter, W2... Opening, W3... Pitch.

Claims

1. An ultrasonic element having a transmitting surface for transmitting ultrasonic waves, and transmitting the ultrasonic waves in a transmission direction intersecting the transmitting surface, A wiring is arranged on the outer circumference of the transmitting surface and connected to the ultrasonic element, A shielding member covering the aforementioned wiring, A retaining member is arranged on the outer circumference of the shield member and extends in the transmission direction, A protective member facing the transmitting surface and having a hole through which the ultrasonic waves pass, The shield member is provided with a shield opening facing the transmitting surface. The holding member is provided with a holding member opening facing the transmitting surface, The protective member is positioned in the opening of the retaining member. Ultrasonic device.

2. The holding member opening is wider than the transmitting surface and the shield opening. The ultrasonic apparatus according to claim 1.

3. The shielding member is positioned in the transmission direction relative to the transmission surface. The shielding opening is wider than the transmitting surface. The ultrasonic apparatus according to claim 1.

4. The angle between the imaginary line connecting the end of the shielding aperture and the center of the transmitting surface and the vertical line of the transmitting surface passing through the center of the transmitting surface is wider than the side lobe half-power angle, which is the half-power of the side lobes of the ultrasonic waves transmitted from the transmitting surface. The ultrasonic apparatus according to claim 3.

5. A media transport device for transporting media, A medium transport path for transporting the aforementioned medium, A retaining member having a retaining member opening, An ultrasonic element that transmits ultrasonic waves is positioned away from the medium transport path relative to the holding member, A wiring is arranged on the outer circumference of the transmitting surface of the ultrasonic element and connects to the ultrasonic element, A shielding member covering the aforementioned wiring, A protective member having a hole that allows the ultrasonic waves to pass through, facing the transmitting surface of the ultrasonic element, It is equipped with an ultrasonic transmitting unit having The shield member is provided with a shield opening facing the transmitting surface. The holding member opening faces the transmitting surface, The protective member is positioned in the opening of the retaining member. Media transport device.

6. A second retaining member facing the aforementioned retaining member, A second ultrasonic element is positioned away from the medium transport path relative to the second holding member and has a receiving surface for receiving the ultrasonic waves, A second wiring is arranged on the outer circumference of the receiving surface and connected to the second ultrasonic element, A second shielding member covering the second wiring, The ultrasonic receiving unit comprises a second protective member that faces the receiving surface of the second ultrasonic element and allows the ultrasonic waves to pass through, The second shield member is provided with a second shield opening facing the receiving surface, The second holding member is provided with a second holding member opening that faces the receiving surface. The second protective member is positioned in the opening of the second retaining member. The medium transport device according to claim 5.

Images