Ultrasonic device

Abstract

To provide an ultrasonic device which has little risk of sensitivity of an ultrasonic element lowering due to a fine foreign object.SOLUTION: An ultrasonic device 9 includes: an ultrasonic element 20 which executes at least one of transmitting ultrasonic waves 23 along a first axis 26 and receiving the ultrasonic waves 23 inputted along the first axis 26; and a protective member 25 provided on the first axis 26, and for covering the ultrasonic element 20. The protective member 25 includes: a first surface 25a in which at least one hole part 27 is provided for allowing the ultrasonic waves 23 travelling along the first axis 26 to pass; and a second surface 25b which crosses with the first surface 25a, and in which a first opening 28 is provided for discharging a foreign object which has entered from at least one hole part 27.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to ultrasound devices. [Background technology]

[0002] Printers and scanners equipped with a paper feed device are widely used. These devices are equipped with a multi-feed detection device for detecting when multiple sheets of paper are fed at the same time. For example, Patent Document 1 discloses a multi-feed detection device equipped with an ultrasonic device. According to this document, the ultrasonic device includes an ultrasonic element. Because the ultrasonic element is fragile, it is housed inside a housing that protects the ultrasonic element. A wire mesh is installed in the housing in the area where the ultrasonic waves pass through. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-25242 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the protective wire mesh of Patent Document 1 allows fine foreign matter, such as paper dust and dirt, generated from the paper to pass through the wire mesh and enter the housing. The foreign matter that enters can adhere to and accumulate on the ultrasonic element. Furthermore, the configuration of Patent Document 1 does not include a mechanism for expelling foreign matter that has adhered to the ultrasonic element. In other words, with the prior art, there was a risk that the sensitivity of the ultrasonic element would be reduced by fine foreign matter. [Means for solving the problem]

[0005] The ultrasonic device comprises an ultrasonic element that performs at least one of transmitting ultrasonic waves along a first axis and receiving the ultrasonic waves input along the first axis, and a protective member that is provided on the first axis and covers the ultrasonic element, the protective member having a first surface that is provided with at least one hole that allows the ultrasonic waves traveling along the first axis to pass through, and a second surface that intersects the first surface and is provided with a first opening that expels foreign matter that has entered through the at least one hole. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic perspective view showing the configuration of an image scanner according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional side view showing the configuration of a conveying unit of the image scanner. [Figure 3] FIG. 1 is a schematic perspective view showing the configuration of an ultrasound device. [Figure 4] FIG. 1 is a schematic perspective view showing the configuration of an ultrasound device. [Figure 5] FIG. 1 is a schematic side view showing the configuration of an ultrasound device. [Figure 6] FIG. 1 is a schematic cross-sectional side view showing the configuration of an ultrasound device. [Figure 7] FIG. 2 is a schematic cross-sectional side view of a main part showing the configuration of an ultrasonic element. [Figure 8] FIG. 3 is a schematic side view illustrating the arrangement of a transmitter and a receiver. [Figure 9] FIG. 2 is a control block diagram showing the control configuration of the image scanner. [Figure 10] FIG. 10 is a schematic cross-sectional side view for explaining boundary conditions of the simulation. [Figure 11] FIG. 10 is a schematic cross-sectional side view for explaining boundary conditions of the simulation. [Figure 12] FIG. 10 is a diagram for explaining a simulation result. [Figure 13] FIG. 10 is a schematic cross-sectional side view showing the configuration of an ultrasound device according to a second embodiment. [Figure 14] FIG. 10 is a diagram for explaining a simulation result. [Figure 15]FIG. 10 is a schematic perspective view of an ultrasound device according to a third embodiment. [Figure 16] FIG. 10 is a schematic plan view of an ultrasonic device according to a fourth embodiment. [Figure 17] FIG. 1 is a schematic plan view of an ultrasound device. [Figure 18] FIG. 1 is a schematic plan view of an ultrasound device. [Figure 19] FIG. 10 is a schematic side view of an ultrasound device according to a fifth embodiment. [Figure 20] FIG. 10 is a diagram for explaining a simulation result in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0007] First embodiment In this embodiment, a characteristic example of an image scanner and an ultrasound device mounted on the image scanner will be described.

[0008] The image scanner 1 shown in Figure 1 is an example of an electronic device. The image scanner 1 comprises a device main body 2 and a paper support 3. The device main body 2 has a feed slot 4 at the connection point with the paper support 3. Paper is supplied from the feed slot 4. The direction in which the paper is supplied is the transport direction, downstream direction, and T-positive direction. The T-negative direction is the upstream direction. Of the directions perpendicular to the T-positive direction on the paper at the feed slot 4, the direction facing left in the figure is the S-positive direction. The device main body 2 has an exit slot 5 located on the T-positive side of the feed slot 4. The paper from which the image has been read is discharged from the exit slot 5. Of the directions perpendicular to the S-positive and T-positive directions, the direction facing upper left in the figure is the U-positive direction. The U-positive direction is the thickness direction of the paper at the paper support 3.

[0009] 2, the device main body 2 is provided with a transport unit 7 that transports paper sheets 6 as an object, a scanning unit 8 that reads an image of the transported paper sheets 6, an ultrasonic device 9 that detects double feeding of paper sheets 6, and a control unit 11 that controls the image scanner 1. Note that in this embodiment, paper sheets 6 are used as the object, and an example in which the ultrasonic device 9 detects double feeding of paper sheets 6 is shown, but this is not limiting. The object can be various media, such as film or fabric, for example.

[0010] Paper sheets 6 placed on paper support 3 are fed one sheet at a time to feed opening 4. The fed paper sheets 6 are transported by transport unit 7 along a predetermined transport path 12 within device main body 2. Then, after the image is read by scanning unit 8 at a reading position along the transport, the paper is discharged from discharge opening 5, which opens at the front lower part of device main body 2. The feed opening 4 side of transport path 12 is the upstream side. The discharge opening 5 side of transport path 12 is the downstream side.

[0011] The transport unit 7 transports multiple sheets of paper 6 set on the paper support 3 one by one in the transport direction. The transport unit 7 feeds the paper 6 sent from the feed opening 4 into the device main body 2. The transport unit 7 transports the fed paper 6 along a predetermined transport path 12.

[0012] The transport unit 7 includes a first pair of feed rollers 13 arranged upstream of the transport path 12. Furthermore, the transport unit 7 includes a second pair of feed rollers 14 arranged downstream of the first pair of feed rollers 13. Furthermore, the transport unit 7 includes a first pair of transport rollers 15 arranged upstream of the scanning unit 8. Furthermore, the transport unit 7 includes a second pair of transport rollers 16 arranged downstream of the scanning unit 8.

[0013] The first feeding roller pair 13 is composed of a first driving roller 13a and a first driven roller 13b. The second feeding roller pair 14 is composed of a second driving roller 14a and a second driven roller 14b. The first transport roller pair 15 is composed of a third driving roller 15a and a third driven roller 15b. The second transport roller pair 16 is composed of a fourth driving roller 16a and a fourth driven roller 16b.

[0014] The first drive roller 13a, the second drive roller 14a, the third drive roller 15a, and the fourth drive roller 16a are driven to rotate by the power of a transport motor 17, which is a power source. The transport motor 17 is controlled by the control unit 11. The first driven roller 13b, the second driven roller 14b, the third driven roller 15b, and the fourth driven roller 16b are driven by the first drive roller 13a, the second drive roller 14a, the third drive roller 15a, and the fourth drive roller 16a, respectively.

[0015] The second driven roller 14b of the second feed roller pair 14 is a retard roller. The coefficient of friction of the outer circumferential surface of the second driven roller 14b with respect to the paper 6 is greater than the coefficient of friction of the outer circumferential surface of the second drive roller 14a with respect to the paper 6. Therefore, the second feed roller pair 14 functions as a separation mechanism that separates the paper 6 one by one and sends it out in the positive direction T. As the first feed roller pair 13 rotates, the multiple paper sheets 6 stacked on the paper support 3 are fed one by one, starting from the top one, through the feed opening 4 into the device main body 2. As the second feed roller pair 14 rotates, the paper sheets 6 are separated one by one. Next, the paper sheets 6 are fed downstream along the transport path 12.

[0016] An ultrasonic device 9 is provided between the second feeding roller pair 14 and the first transport roller pair 15. The ultrasonic device 9 is a double feed sensor that detects double feed of the paper 6 transported by the transport unit 7.

[0017] The ultrasonic device 9 is provided with a pair of ultrasonic elements 20. One of the pair of ultrasonic elements 20 is a transmitting unit 21. The transmitting unit 21 transmits ultrasonic waves. The other of the pair of ultrasonic elements 20 is a receiving unit 22. The receiving unit 22 receives ultrasonic waves.

[0018] The transmitter 21 and receiver 22 are arranged on either side of the transport path 12 along which the paper 6 is transported. The transmitter 21 transmits ultrasonic waves 23 toward the paper 6 being transported along the transport path 12 by the transport unit 7. The ultrasonic waves 23 transmitted from the transmitter 21 pass through the paper 6. The receiver 22 receives the ultrasonic waves 23 that have passed through the paper 6. The receiver 22 outputs a reception signal corresponding to the sound pressure of the received ultrasonic waves 23 to the controller 11. The controller 11 detects double feeding of the paper 6 based on the intensity of the sound pressure indicated by the reception signal.

[0019] A scanning unit 8 that reads an image on the paper 6 is provided between the first pair of transport rollers 15 and the second pair of transport rollers 16 on the transport path 12. The scanning unit 8 is made up of a first scanning unit 8a and a second scanning unit 8b that are provided on either side of the transport path 12.

[0020] The scanning unit 8 is made up of a light source 18 that irradiates light onto the paper 6 being transported, and an image sensor 19 that extends in the S-positive direction. The S-positive direction in which the image sensor 19 extends is called the main scanning direction. The first scanning unit 8a and the second scanning unit 8b each have a light source 18 and an image sensor 19. The side of the paper 6 facing the U-negative direction is the front side. In the normal reading mode in which the front side of the paper 6 is read, the first scanning unit 8a performs the reading operation. In the double-sided reading mode in which both the front and back sides of the paper 6 are read, both the first scanning unit 8a and the second scanning unit 8b perform the reading operation. The light source 18 and the image sensor 19 are electrically connected to the control unit 11. The control unit 11 controls the scanning process to read the image on the paper 6. After the scanning process is completed, the paper 6 is discharged from the discharge port 5.

[0021] As shown in FIGS. 3 to 6, the ultrasonic device 9 includes a circuit board 24. The circuit board 24 is a rectangular plate. One of the longitudinal directions of the circuit board 24 is the X-positive direction. One of the lateral directions of the circuit board 24 is the Y-positive direction. One of the thickness directions of the circuit board 24 is the Z-positive direction. The X-positive direction, the Y-positive direction, and the Z-positive direction are perpendicular to one another. FIG. 3 is a view of the ultrasonic device 9 as seen from the X-negative direction, the Y-negative direction, and the Z-positive direction. FIG. 4 is a view of the ultrasonic device 9 as seen from the X-negative direction, the Y-positive direction, and the Z-positive direction. FIG. 5 is a view of the ultrasonic device 9 as seen from the Y-negative direction. FIG. 6 is a view of the cross section taken along line AA in FIG. 5.

[0022] The surface of the circuit board 24 facing the positive Z direction is the board front surface 24a. The surface of the circuit board 24 facing the negative Z direction is the board back surface 24b. The ultrasonic device 9 has an ultrasonic element 20 and a protective member 25 on the board front surface 24a. The ultrasonic element 20 is a transmitting unit 21 or a receiving unit 22. The transmitting unit 21 transmits ultrasonic waves 23 along a first axis 26. The receiving unit 22 receives ultrasonic waves 23 input along the first axis 26. The ultrasonic element 20 performs at least one of transmitting ultrasonic waves 23 along the first axis 26 and receiving ultrasonic waves 23 input along the first axis 26.

[0023] The protective member 25 is provided on the first axis 26. The protective member 25 covers the ultrasonic element 20. The protective member 25 has a first surface 25a, a second surface 25b, a third surface 25c, a fourth surface 25d, and a fifth surface 25e. The first surface 25a is disposed in the Z positive direction of the ultrasonic element 20. The first surface 25a is provided with a plurality of holes 27 that allow the ultrasonic waves 23 traveling along the first axis 26 to pass through. Each hole 27 is an elongated hole, and the longitudinal direction of each hole 27 is parallel to the longitudinal direction of the circuit board 24. When the ultrasonic element 20 is the transmitting unit 21, the ultrasonic waves 23 transmitted by the transmitting unit 21 travel through the hole 27 toward the receiving unit 22. When the ultrasonic element 20 is the receiving unit 22, the ultrasonic waves 23 traveling from the transmitting unit 21 travel through the hole 27 toward the receiving unit 22. Note that the number of holes 27 may be one as long as the ultrasonic waves 23 can pass through the hole 27. At least one hole 27 is provided in the first surface 25a. When the number of holes in the hole 27 is one, the size of the hole 27 is preferably equal to or larger than the size of the ultrasonic element 20. This can reduce reflection of the ultrasonic waves 23 at the hole 27.

[0024] First surface 25a faces the positive Z direction and the negative X direction. Of the ultrasonic waves 23 transmitted by transmitter 21, those reflected by protective member 25 on the back side of first surface 25a are directed toward circuit board 24 rather than toward transmitter 21. This reduces the influence of ultrasonic waves 23 reflected by protective member 25 on transmitter 21.

[0025] The second surface 25b faces the negative Y direction. The second surface 25b is disposed in the negative Y direction of the ultrasonic element 20. The second surface 25b intersects with the first surface 25a. The second surface 25b is provided with a first opening 28 that discharges foreign matter that has entered through the multiple holes 27.

[0026] According to this configuration, the ultrasonic element 20 can be protected by the protective member 25. Small foreign matter can enter through the multiple holes 27 provided in the protective member 25. The small foreign matter is paper dust and dirt generated from the paper. When the paper 6 moves between the transmitting unit 21 and the receiving unit 22, an air flow 30 is generated as the paper 6 moves. By causing the air flow 30 to enter through the multiple holes 27 and pass through the first opening 28, the foreign matter can be expelled from the first opening 28 of the second surface 25b. As a result, it is possible to prevent the sensitivity of the ultrasonic element 20 from being reduced by the foreign matter.

[0027] The third surface 25c faces the Y-positive direction. The third surface 25c intersects with the first surface 25a. The third surface 25c faces the second surface 25b across the ultrasonic element 20. The third surface 25c is provided with a second opening 29 that discharges foreign matter that has entered through the multiple holes 27.

[0028] According to this configuration, by causing the air flow 30 to enter through the plurality of holes 27 and pass through the second openings 29, foreign matter can be added to the first openings 28 of the second surface 25b and discharged from the second openings 29 of the third surface 25c. As a result, it is possible to prevent the sensitivity of the ultrasonic element 20 from being reduced by foreign matter.

[0029] The fourth surface 25d faces in the negative X direction. A third opening 31 is disposed between the second surface 25b and the fourth surface 25d. Small foreign particles pass through the third opening 31 and move out of the protective member 25. Therefore, accumulation of small foreign particles between the second surface 25b and the fourth surface 25d is suppressed.

[0030] The fifth surface 25e faces in the X-positive direction. A fourth opening 32 is disposed between the second surface 25b and the fifth surface 25e. Small foreign matter passes through the fourth opening 32 and moves out of the protective member 25. Therefore, accumulation of small foreign matter between the second surface 25b and the fifth surface 25e is suppressed.

[0031] A fifth opening 33 is disposed between the third surface 25c and the fourth surface 25d. Small foreign matter passes through the fifth opening 33 and moves out of the protective member 25. Therefore, accumulation of small foreign matter between the third surface 25c and the fourth surface 25d is suppressed.

[0032] A sixth opening 34 is disposed between the third surface 25c and the fifth surface 25e. Small foreign matter passes through the sixth opening 34 and moves out of the protective member 25. Therefore, accumulation of small foreign matter between the third surface 25c and the fifth surface 25e is suppressed.

[0033] The protective member 25 has a first protrusion 25f protruding in the negative Z direction on the fourth surface 25d. The circuit board 24 has a first hole 24c at a position corresponding to the first protrusion 25f. The first protrusion 25f is inserted into the first hole 24c. The protective member 25 has a second protrusion 25g protruding in the negative Z direction on the fifth surface 25e. The circuit board 24 has a second hole 24d at a position opposite the second protrusion 25g. The second protrusion 25g is inserted into the second hole 24d. The first protrusion 25f and the second protrusion 25g protrude from the back surface 24b of the board.

[0034] As shown in Figure 5, the circuit board 24 has a ground terminal 35 on the back surface 24b of the board that surrounds the first hole 24c. The circuit board 24 has a ground terminal 35 on the back surface 24b of the board that surrounds the second hole 24d. The first protrusion 25f and the second protrusion 25g are fixed to the ground terminal 35 by soldering. The protective member 25 is made of a conductive member such as metal. The ground terminal 35 is electrically connected to metal components of the device main body 2. The protective member 25 protects the ultrasonic element 20 from static electricity and electromagnetic waves.

[0035] 3 and 4, the circuit board 24 has a third hole 24e in the positive X direction of the protective member 25. The third hole 24e is used when fixing the ultrasonic device 9 with a screw.

[0036] As shown in FIG. 7, when the ultrasonic element 20 is the transmitting unit 21, the ultrasonic element 20 includes an element substrate 36 and a piezoelectric element 37. The element substrate 36 includes a substrate main body 38 and a diaphragm 39. The diaphragm 39 is provided on one side of the substrate main body 38. One side of the substrate thickness direction of the element substrate 36 is the Z positive direction. The Z positive direction is the direction in which the ultrasonic waves 23 are transmitted. The Z positive direction is parallel to the first axis 26. The substrate main body 38 is a substrate that supports the diaphragm 39. The substrate main body 38 is made of a semiconductor substrate such as Si. The substrate main body 38 has an opening 38a that penetrates the substrate main body 38 along the Z direction. When viewed from the Z positive direction, the opening 38a overlaps with the piezoelectric element 37.

[0037] The diaphragm 39 is made of a laminate of SiO2 and ZrO2 or the like. The diaphragm 39 is provided on the negative Z side of the substrate main body 38. The diaphragm 39 is supported by a partition wall 38b of the substrate main body 38 that forms the opening 38a. The diaphragm 39 closes the negative Z side of the opening 38a. When viewed from the positive Z direction, the part of the diaphragm 39 that overlaps with the opening 38a is the vibrating part 39a.

[0038] The piezoelectric element 37 is provided on the vibration plate 39 on the negative Z direction side. When viewed from the positive Z direction, the piezoelectric element 37 is provided at a position overlapping with each vibration portion 39a. The piezoelectric element 37 includes a first electrode 41, a piezoelectric film 42, and a second electrode 43. The first electrode 41, the piezoelectric film 42, and the second electrode 43 are laminated in this order on the vibration plate 39.

[0039] One ultrasonic transducer 44 is configured by one vibration part 39a and one piezoelectric element 37. In the ultrasonic element 20, the ultrasonic transducers 44 are arranged in a two-dimensional array structure.

[0040] When the ultrasonic element 20 is the transmitting unit 21, a pulse wave voltage of a predetermined frequency is applied between the first electrode 41 and the second electrode 43 of each ultrasonic transducer 44, causing the piezoelectric film 42 to expand and contract. The expansion and contraction of the piezoelectric film 42 causes the vibrating unit 39a to vibrate at a frequency that corresponds to the opening width of the opening 38a, etc. Ultrasonic waves 23 are transmitted from the vibrating unit 39a in the positive Z direction along the first axis 26. The surface of the element substrate 36 on the positive Z direction side becomes the transmission surface 45 of the transmitting unit 21 for transmitting the ultrasonic waves 23.

[0041] When the ultrasonic element 20 is the receiving unit 22, the receiving unit 22 has the same configuration as the transmitting unit 21. The transmitting surface 45 becomes the receiving surface 46. The receiving unit 22 receives ultrasonic waves 23 input from the positive Z direction side toward the negative Z direction side. When ultrasonic waves 23 are input from the opening 38a along the first axis 26, the vibrating unit 39a vibrates in the receiving unit 22. This generates a potential difference between the first electrode 41 side and the second electrode 43 side of the piezoelectric film 42, and a reception signal corresponding to this potential difference is output from the receiving unit 22 to the control unit 11. The control unit 11 detects the intensity of the ultrasonic waves 23.

[0042] Next, the arrangement of the transmitter 21 and the receiver 22 will be described using Figure 8. The image scanner 1 has a first guide plate 47 and a second guide plate 48. The paper 6 passes between the first guide plate 47 and the second guide plate 48. The first guide plate 47 has a first passing hole 47a. The second guide plate 48 has a second passing hole 48a. The centers of the first passing hole 47a and the second passing hole 48a are positioned on the first axis 26. The ultrasonic waves 23 transmitted by the transmitter 21 pass through the first passing hole 47a and the second passing hole 48a and reach the receiver 22.

[0043] When there is no paper 6 between the first passing hole 47a and the second passing hole 48a, the intensity of the ultrasonic waves 23 that reach the receiving unit 22 is stronger than when there is paper 6. By determining the intensity of the ultrasonic waves 23 received by the receiving unit 22, it is possible to detect whether or not there is paper 6 between the first passing hole 47a and the second passing hole 48a.

[0044] When there are two sheets of paper 6 between the first passing hole 47a and the second passing hole 48a, the intensity of the ultrasonic waves 23 that reach the receiving unit 22 is weaker than when there is one sheet of paper 6. By determining the intensity of the ultrasonic waves 23 received by the receiving unit 22, it is possible to detect whether there is one or two sheets of paper 6 between the first passing hole 47a and the second passing hole 48a.

[0045] The first guide plate 47 has a first support portion 47b on the U-positive side. The circuit board 24 of the transmitter 21 is fixed to the first guide plate 47 with screws. The second guide plate 48 has a second support portion 48b on the U-negative side. The circuit board 24 of the receiver 22 is fixed to the second guide plate 48 with screws.

[0046] The transmitting unit 21 and the receiving unit 22 are disposed in opposing positions. The first axis 26 of the transmitting unit 21 and the first axis 26 of the receiving unit 22 are coaxial. The transmitting unit 21 transmits ultrasonic waves 23 toward the paper 6. The receiving unit 22 receives the ultrasonic waves 23 input from the paper 6.

[0047] According to this configuration, the transmitting unit 21 transmits ultrasonic waves 23 to the paper 6. The ultrasonic waves 23 transmitted from the transmitting unit 21 are input to the paper 6, and the ultrasonic waves 23 that have passed through the paper 6 are received by the receiving unit 22. Because the transmitting unit 21 and the receiving unit 22 are arranged coaxially, the receiving unit 22 can receive the ultrasonic waves 23 with good sensitivity.

[0048] The first axis 26 is inclined at a first angle 49 with respect to the normal to the surface of the paper 6. With this configuration, it is possible to suppress multiple reflections that occur between the paper 6 and the transmitter 21. In other words, the paper 6 and the transmission surface 45 of the transmitter 21 are not parallel. Of the ultrasonic waves 23 transmitted by the transmitter 21, the ultrasonic waves 23 that are reflected by the surface of the paper 6 do not travel in the direction of the transmitter 21. Therefore, it is possible to suppress multiple reflections.

[0049] In the protective member 25 of the transmitting unit 21, the normal to the first surface 25a is inclined at a second angle 51 with respect to the normal to the surface of the paper 6. In the protective member 25 of the receiving unit 22, the normal to the first surface 25a is also inclined at a second angle 51 with respect to the normal to the surface of the paper 6. The surface of the first surface 25a and the paper 6 are not parallel.

[0050] This configuration can suppress multiple reflections that occur between the paper 6 and the first surface 25a of the protective member 25. The second angle 51 on the transmitting unit 21 side and the second angle 51 on the receiving unit 22 side may be the same as or different from each other.

[0051] In the protective member 25 of the transmitting unit 21, the normal to the first surface 25a is inclined at a third angle 52 with respect to the first axis 26. In the protective member 25 of the receiving unit 22, the normal to the first surface 25a is also inclined at a third angle 52 with respect to the first axis 26. The first surface 25a and the surface of the ultrasonic element 20 are not parallel to each other.

[0052] This configuration can suppress multiple reflections that occur between the first surface 25a of the protective member 25 and the ultrasonic element 20. The third angle 52 on the transmitting unit 21 side and the third angle 52 on the receiving unit 22 side may be the same as or different from each other.

[0053] It is preferable that at least one of the first angle 49, the second angle 51, and the third angle 52 is an angle of 5° or more. In this embodiment, for example, the first angle 49 is 20°, the second angle 51 is 10°, and the third angle 52 is 10°.

[0054] According to this configuration, when first angle 49 is 5° or greater, multiple reflections occurring between paper 6 and ultrasonic element 20 can be suppressed. When second angle 51 is 5° or greater, multiple reflections occurring between paper 6 and first surface 25a of protective member 25 can be suppressed. When third angle 52 is 5° or greater, multiple reflections occurring between first surface 25a of protective member 25 and ultrasonic element 20 can be suppressed.

[0055] In the ultrasonic device 9 provided with the transmitting unit 21, when multiple reflections of the ultrasonic waves 23 occur, the residual vibrations affect the next transmitted ultrasonic waves 23. In the ultrasonic device 9 provided with the receiving unit 22, the ultrasonic device 9 converts the waveform of the ultrasonic waves 23 into a received signal. When multiple reflections of the ultrasonic waves 23 occur, the residual vibrations affect the received signal. By suppressing the multiple reflections as in the above embodiment, the effects of the residual vibrations can be suppressed.

[0056] 9, the circuit board 24 on which the transmitting unit 21 is mounted is a transmitting circuit board 53. A transmitting circuit 54 is provided on the transmitting circuit board 53. The transmitting circuit 54 is electrically connected to each ultrasonic transducer 44 of the transmitting unit 21. The transmitting circuit 54 generates a drive signal for driving each ultrasonic transducer 44.

[0057] The circuit board 24 on which the receiving unit 22 is mounted is the receiving circuit board 55. The receiving circuit board 55 is provided with a receiving circuit and the like that processes the received signal and outputs it to the control unit 11. The receiving circuit is composed of a bandpass filter 56, an amplifier 57, a sample-and-hold circuit 58, a comparator 59, and the like. The received signal output from the receiving unit 22 is input to the bandpass filter 56. The bandpass filter 56 removes noise components and the like from the received signal. The amplifier 57 amplifies the received signal so that it has a predetermined signal strength or higher. Next, the received signal is input to the sample-and-hold circuit 58. The sample-and-hold circuit 58 samples the received signal at a predetermined frequency. The sampled received signal is input to the comparator 59. The comparator 59 detects, from the sampled received signals, those whose signal strength exceeds a predetermined judgment strength. The comparator 59 transmits the received signal that exceeds the judgment strength to the control unit 11.

[0058] The control unit 11 includes a calculation unit 61 configured with a CPU (Central Processing Unit) and the like, and a storage unit 62 configured with a storage circuit such as a memory. The control unit 11 is electrically connected to the transport motor 17 of the transport unit 7, the scan unit 8, the transmission circuit 54 of the transmission circuit board 53, and the comparator 59 of the reception circuit board 55. The control unit 11 controls the driving of the transport motor 17, the scan unit 8, the transmission unit 21, and the reception unit 22. The control unit 11 is electrically connected to an interface unit 63. The interface unit 63 receives various data and signals input from an external device 64 such as a personal computer. The interface unit 63 outputs the read data read by the image scanner 1 to the external device 64.

[0059] The memory unit 62 stores various data and programs for controlling the image scanner 1. The calculation unit 61 reads the various programs stored in the memory unit 62. The calculation unit 61 executes various functions in accordance with the various programs. The calculation unit 61 functions as a transport control unit 65, a reading control unit 66, a multifeed determination unit 67 as a state detection unit, and the like.

[0060] The transport control unit 65 controls the transport motor 17 of the transport unit 7. The transport control unit 65 causes the transport motor 17 to rotate the first feed roller pair 13, the second feed roller pair 14, the first transport roller pair 15, and the second transport roller pair 16. The transport control unit 65 feeds the paper 6 set on the paper support 3 one sheet at a time into the device main body 2. The transport control unit 65 causes the fed paper 6 to be transported along the transport path 12. The reading control unit 66 controls the scanning unit 8 while the paper 6 is being transported. The reading control unit 66 causes the scanning unit 8 to read the image on the paper 6.

[0061] The multifeed determination unit 67 detects the multifeed state of the paper 6. The receiving unit 22 receives ultrasonic waves 23 from the paper 6 and outputs a received signal. The multifeed determination unit 67 controls the ultrasonic device 9 to input the received signal from the receiving unit 22. The multifeed determination unit 67 determines the state of the paper 6 based on the received signal. The state of the paper 6 indicates whether or not it has been multifed. Specifically, if the voltage value of the received signal is smaller than the determination value, the multifeed determination unit 67 determines that the paper 6 has been multifed. If the multifeed determination unit 67 determines that the paper 6 has been multifed, the conveyance control unit 65 stops conveying the paper 6. The multifeed determination unit 67 is included in the ultrasonic device 9.

[0062] According to this configuration, when the receiving unit 22 receives the ultrasonic waves 23, it outputs a reception signal corresponding to the sound pressure of the ultrasonic waves 23 received by the receiving unit 22. The degree of penetration of the ultrasonic waves 23 through the paper 6 can be detected based on the signal strength of the reception signal. The multifeed determination unit 67 detects the degree of penetration of the ultrasonic waves 23 through the paper 6 based on the reception signal. The multifeed determination unit 67 can detect the thickness and type of the paper 6 and whether or not a multifeed state has occurred based on the degree of penetration of the ultrasonic waves 23.

[0063] Next, a simulation of air being discharged from the first opening 28 and the second opening 29 will be described. As shown in Fig. 10, in the simulation model, a guide plate 68 is installed in the Z positive direction of the first surface 25a. The guide plate 68 corresponds to the first guide plate 47 and the second guide plate 48. When viewed from the Z positive direction, the guide plate 68 has a passing hole 68a at a location overlapping with the ultrasonic element 20. The air flow 30 passes through the passing hole 68a and reaches the first surface 25a.

[0064] Guide plate 68 is connected to circuit board 24 in the negative X direction. Support portion 69 is disposed on fifth surface 25e in the positive X direction. Support portion 69 connects circuit board 24 and guide plate 68 together.

[0065] Fig. 11 is a cross-sectional view taken along line BB in Fig. 10. As shown in Fig. 11, guide plates 68 are also arranged on the Y negative side of second surface 25b and on the Y positive side of third surface 25c.

[0066] In Figure 12, air flow 30 is fast in dark places. Air flow 30 is slow in bright places. The arrows indicate the direction of air flow 30. Air flow 30 passes through hole 27 and enters the interior of protective member 25. Air flow 30 reaches ultrasonic element 20 or circuit board 24. After reaching ultrasonic element 20 or circuit board 24, air flow 30 changes direction to the positive Y direction or the negative Y direction. Air flow 30 moving in the negative Y direction passes through first opening 28 and proceeds to the outside of protective member 25. Air flow 30 moving in the positive Y direction passes through second opening 29 and proceeds to the outside of protective member 25.

[0067] Therefore, the air flow 30 flows smoothly inside the protective member 25. The flow rate of the air flow 30 is high and the flow speed is fast above the ultrasonic element 20. Therefore, fine foreign matter is less likely to adhere to the ultrasonic element 20. Even if fine foreign matter adheres to the ultrasonic element 20, it is moved to the outside of the protective member 25 by the air flow 30. As a result, it is possible to prevent the sensitivity of the ultrasonic element 20 from being reduced by fine foreign matter.

[0068] 20 shows a comparative example. Protective member 71 of the comparative example does not have first opening 28 or second opening 29. Air flow 30 passes through hole portion 27 and enters the interior of protective member 71. Air flow 30 circulates inside protective member 71. At this time, the air pressure inside protective member 71 increases, making it difficult for air flow 30 to enter the interior of protective member 71.

[0069] Therefore, the air flow 30 tends to stagnate inside the protective member 71. Because the flow rate and speed of the air flow 30 above the ultrasonic elements 20 are low, small foreign matter tends to adhere to the ultrasonic elements 20. When small foreign matter adheres to the ultrasonic elements 20, it remains there. As a result, there is a risk that the sensitivity of the ultrasonic elements 20 will decrease due to the small foreign matter.

[0070] Second embodiment This embodiment differs from the first embodiment in that the protective member does not have the second opening 29. In the following description, the same reference numerals will be used to designate items that have already been described, and description thereof will be omitted or simplified.

[0071] 13, an ultrasonic device 72 includes a protective member 73. The protective member 73 includes a hole 27 on a first surface 73a. The protective member 73 includes a first opening 28 on a second surface 73b. The protective member 73 does not include an opening on a third surface 73c. ​​The first surface 73a, the second surface 73b, and the third surface 73c correspond to the first surface 25a, the second surface 25b, and the third surface 25c of the first embodiment, respectively.

[0072] The light and dark areas and arrows in Figure 14 are the same as those in Figure 12. As shown in Figure 14, air flow 30 passes through hole 27 and enters the interior of protective member 73. Air flow 30 reaches ultrasonic element 20 or circuit board 24. After reaching ultrasonic element 20 or circuit board 24, air flow 30 changes direction to the positive Y direction or the negative Y direction. Air flow 30 moving in the negative Y direction passes through first opening 28 and proceeds to the outside of protective member 73. Air flow 30 moving in the positive Y direction circulates inside protective member 73.

[0073] Therefore, the air flow 30 flows smoothly inside the protective member 73 in the Y-negative direction. The air flow 30 has a large flow rate and a fast flow speed above the ultrasonic elements 20 in the Y-negative direction. Fine foreign matter is less likely to adhere to the ultrasonic elements 20. Even when fine foreign matter adheres to the ultrasonic elements 20, it is moved to the outside of the protective member 73 by the air flow 30. As a result, it is possible to prevent the sensitivity of the ultrasonic elements 20 from being reduced by fine foreign matter on the Y-negative direction side.

[0074] The protective member 73 intersects with the first surface 73a and has a second surface 73b provided with first openings 28 that discharge foreign matter that has entered through the multiple holes 27. With this configuration, the ultrasonic element 20 can be protected by the protective member 73. Foreign matter may enter through the multiple holes 27 provided in the protective member 73. By passing a stream of air through the multiple holes 27, this foreign matter can be discharged from the first openings 28 in the second surface 73b. As a result, it is possible to prevent the sensitivity of the ultrasonic element 20 from being reduced by foreign matter.

[0075] Third embodiment This embodiment differs from the first embodiment in that a sound absorbing portion is provided on the first surface 25a of the protective member 25. In the following description, the same reference numerals will be used to designate items that have already been described, and their description will be omitted or simplified.

[0076] 15, a sound absorbing portion 77 is provided on the first surface 25a of the protective member 25 of the ultrasonic device 76, surrounding the multiple holes 27. When viewed from the Z direction, the sound absorbing portion 77 is frame-shaped. The sound absorbing portion 77 is formed by providing a porous member such as urethane. The first guide plate 47 and the second guide plate 48 may be roughened on the surfaces facing the first surface 25a to scatter the ultrasonic waves 23.

[0077] According to this configuration, a sound absorbing section 77 is provided on the first surface 25a. The sound absorbing section 77 does not reflect the ultrasonic waves 23. Therefore, it is possible to suppress multiple reflections of the ultrasonic waves 23 between the first surface 25a and the paper 6. If multiple reflection components are received by the ultrasonic element 20, the received signal will be large, which may prevent the paper 6 from being properly detected. In this embodiment, it is possible to suppress the multiple reflection components, and it is possible to properly determine whether the paper 6 is being fed multiple times.

[0078] Fourth embodiment In this embodiment, the shape of the hole 27 is different from that of the first embodiment. In the following description, the same reference numerals will be used to designate items that have already been described, and description thereof will be omitted or simplified.

[0079] 16, an ultrasonic device 81 includes a protective member 82. The protective member 82 has a plurality of holes 83 on a first surface 82a. The longitudinal direction of each hole 83 is parallel to the lateral direction of the circuit board 24. The ultrasonic waves 23 and the air flow 30 pass through each hole 83.

[0080] As shown in Figure 17, an ultrasonic device 86 includes a protective member 87. The protective member 87 has a first surface 87a with a plurality of holes 88. The holes 88 include a circular first hole 88a and a long, slotted second hole 88b. When viewed from the positive Z direction, the first hole 88a is disposed at the center of the ultrasonic element 20. The second hole 88b is disposed radially around the first hole 88a. Ultrasonic waves 23 and air flow 30 pass through each hole 88.

[0081] As shown in FIG. 18, an ultrasonic device 91 includes a protective member 92. The protective member 92 has a plurality of holes 93 on a first surface 92a. The holes 93 include a first hole 93a to a ninth hole 93j. The first hole 93a to the ninth hole 93j are arranged in a matrix. When viewed from the Z positive direction, the first hole 93a is arranged at the center of the ultrasonic element 20. The first hole 93a is square.

[0082] The second hole 93b is disposed in the X positive direction of the first hole 93a. The second hole 93b is generally rectangular, with an arc-shaped side on the X positive direction side. The third hole 93c is disposed in the X positive direction and Y negative direction of the first hole 93a. The third hole 93c is generally triangular, with an arc-shaped side on the X positive direction side and Y negative direction side.

[0083] A fourth hole 93d is located in the negative Y direction from the first hole 93a. The fourth hole 93d is generally rectangular, with an arc-shaped side on the negative Y direction side. A fifth hole 93e is located in the negative X direction and negative Y direction from the first hole 93a. The fifth hole 93e is generally triangular, with arc-shaped sides on the negative X direction and negative Y direction side.

[0084] A sixth hole 93f is located in the negative X direction from the first hole 93a. The sixth hole 93f is generally rectangular, with an arc-shaped side on the negative X direction side. A seventh hole 93g is located in the negative X direction and positive Y direction from the first hole 93a. The seventh hole 93g is generally triangular, with arc-shaped sides on the negative X direction side and positive Y direction side.

[0085] An eighth hole 93h is arranged in the Y-positive direction from the first hole 93a. The eighth hole 93h is approximately rectangular, with the side on the Y-positive side forming an arc. A ninth hole 93j is arranged in the X-positive and Y-positive directions from the first hole 93a. The ninth hole 93j is approximately triangular, with the sides on the X-positive and Y-positive sides forming an arc. The ultrasonic waves 23 and the air flow 30 pass through each hole 93.

[0086] The arrangement and shape of the holes are not particularly limited, such as holes 83, 88, and 93, which correspond to the multiple holes 27 in the first embodiment. It is preferable to arrange holes 93 large enough to allow the ultrasonic waves 23 and air flow 30 to flow through. The hole may be a single hole. The hole may be a hole in which the first hole 93a to the ninth hole 93j are connected. The shape of the holes is not particularly limited. The shape of the holes may be circular or rectangular.

[0087] Fifth embodiment In this embodiment, the shapes of the first opening 28 and the second opening 29 are different from those in the first embodiment. In the following description, the same reference numerals will be used to designate items that have already been described, and description thereof will be omitted or simplified.

[0088] 19, an ultrasonic device 96 includes a protective member 97. The protective member 97 includes a first opening 98 on a second surface 97b. The protective member 97 includes a second opening 99 on a third surface 97c. The second surface 97b and the third surface 97c correspond to the second surface 25b and the third surface 25c of the first embodiment, respectively.

[0089] The first opening 98 and the second opening 99 are substantially rectangular. As described above, the second surface 25b and the third surface 25c in the first embodiment may have any shape that allows the air flow 30 to flow easily, and the shapes of the first opening 98 and the second opening 99 are not particularly limited.

[0090] Sixth embodiment In the first embodiment, the transmitting unit 21 was the ultrasonic element 20 that transmitted the ultrasonic waves 23. The receiving unit 22 was the ultrasonic element 20 that received the ultrasonic waves 23. A configuration may be adopted in which one transmitting / receiving unit is provided that performs transmission and reception processing of the ultrasonic waves 23. One of the transmitting / receiving units may transmit the ultrasonic waves 23, and the other may receive the ultrasonic waves 23.

[0091] Seventh embodiment In the first embodiment, the ultrasonic device 9 detects double feeding of the paper 6. The ultrasonic device 9 may be used for purposes other than detecting the paper 6. For example, the ultrasonic device 9 of the first embodiment may be used in a data transmission device that transmits data by ultrasonic waves 23. The ultrasonic device 9 of the first embodiment may be used in an insect repellent device or an animal repellent device that repels insects and animals using ultrasonic waves 23. The ultrasonic device 9 of the first embodiment may be used in an ultrasonic device such as a tactile transmission device that uses ultrasonic waves 23. This device may be configured to include only the transmitting unit 21. The ultrasonic device 9 of the first embodiment may be used in a data receiving device that receives ultrasonic signals transmitted from a data transmission device that uses ultrasonic waves 23. This device may be configured to include only the receiving unit 22.

[0092] The ultrasonic device 9 may be used as a distance measuring sensor that measures the distance from the ultrasonic element 20 to the measurement object. The distance measuring sensor measures the distance from the ultrasonic element 20 to the measurement object based on the time from when the transmitter 21 transmits ultrasonic waves 23 to the measurement object to when the receiver 22 receives the ultrasonic waves 23 reflected by the measurement object.

[0093] The ultrasonic device 9 can achieve the same effect as described above even when used for purposes other than detecting double feed of paper 6. In an ultrasonic device 9 provided with a transmitter 21, transmission sensitivity decreases when foreign matter adheres to the surface of the transmitter 21. In an ultrasonic device 9 provided with a receiver 22, reception sensitivity decreases when foreign matter adheres to the surface of the receiver 22. By introducing air flow 30 through multiple holes 27 and passing it through first opening 28 and second opening 29, foreign matter can be expelled from first opening 28 and second opening 29. As a result, it is possible to prevent the sensitivity of the ultrasonic element 20 from being reduced by foreign matter. [Explanation of symbols]

[0094] 6...paper as target object, 9,72,76,81,86,91,96...ultrasonic device, 20...ultrasonic element, 21...transmitting unit, 22...receiving unit, 23...ultrasonic wave, 25a,73a,82a,87a,92a...first surface, 25b,73b,97b...second surface, 25c,73c,97c...third surface, 25,71,73,82,87,92,97...protective member, 26...first axis, 27,83,88,93...hole portion, 28,98...first opening, 29,99...second opening, 49...first angle, 51...second angle, 52...third angle, 67...multiple feed detection unit as status detection unit, 77...sound absorbing unit.

Claims

1. transmitting an ultrasonic wave along a first axis; and receiving the ultrasonic wave along the first axis. and receiving an ultrasonic signal from an ultrasonic element. a protective member provided on the first axis and covering the ultrasonic element, The protective member includes at least one ultrasonic wave passage member that passes the ultrasonic wave traveling along the first axis. a first surface on which the hole is provided; a first opening intersecting the first surface and configured to discharge foreign matter entering through the at least one hole; a second surface on which the The ultrasonic element is disposed between the first surface and the second surface. and a third surface provided with a second opening for discharging foreign matter that has entered through the two holes. Ultrasound device.

2. 10. The ultrasound device of claim 1, The first surface is provided with a sound absorbing portion surrounding the at least one hole. Ultrasound device.

3. 3. The ultrasound device according to claim 1 or 2, The ultrasonic element transmits the ultrasonic waves toward or from an object. receiving the ultrasonic wave input from a The first axis is inclined at a first angle relative to a normal to the surface of the object. Sonic device.

4. 4. The ultrasound device of claim 3, a normal to the first surface is inclined at a second angle with respect to a normal to the surface of the object; Ultrasound device.

5. 5. The ultrasound device of claim 4, a normal to the first surface inclined at a third angle with respect to the first axis; wave device.

6. 6. The ultrasound device of claim 5, At least one of the first angle, the second angle, and the third angle is an angle of 5 degrees or more. An ultrasonic device characterized by the above.

7. 3. The ultrasound device according to claim 1 or 2, A pair of the ultrasonic elements is provided, and one of the pair of the ultrasonic elements transmits the ultrasonic waves. The other of the pair of ultrasonic elements is a receiving unit that receives the ultrasonic waves. 、 The transmitting unit and the receiving unit are provided at positions facing each other on the first axis. An ultrasonic device characterized by:

8. 8. The ultrasound device of claim 7, the receiving unit receives the ultrasonic waves from an object and outputs a received signal; a state detection unit that detects the state of the object based on the received signal, Ultrasound device.

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