JP5407227B2 - Image acquisition device - Google Patents

Description

  The present invention relates to an image acquisition device for acquiring an image of a medium to be inspected by obtaining optical information from the medium to be inspected using a light receiving sensor.

  As is well known in the art, an image acquisition apparatus that acquires an image of a medium to be inspected using a light receiving sensor is used as a determination apparatus that determines the authenticity of paper sheets such as banknotes, securities, and checks. That is, the image acquisition device emits light from a light source to an inspection medium such as a bill. An image of the medium to be inspected is obtained by receiving the reflected light reflected from the medium to be inspected or the transmitted light transmitted through the medium to be inspected by the light receiving sensor. The medium to be inspected is discriminated by comparing it with the reference image.

  In such an image acquisition apparatus, the medium to be inspected is conveyed at a constant speed along a reference plane that is set horizontally. Then, the medium to be inspected passes below the light receiving sensor array configured by arranging a plurality of light receiving sensors in an array in a direction perpendicular to the conveyance direction of the medium to be inspected and parallel to the reference plane. To do. Each light receiving surface of each light receiving sensor faces the above-described reference surface.

  The light receiving sensor array receives reflected light or transmitted light from the inspection medium existing below the light receiving sensor array, that is, in a region facing each light receiving surface. Then, when the medium to be inspected conveyed at a constant speed passes below the light receiving sensor array, the reflected light or transmitted light from the medium to be inspected is output as a detection signal at regular time intervals. An overall image of the medium to be inspected is obtained from the detection signals obtained at this time.

  In such an image acquisition apparatus, a technique using a roller as means for conveying a medium to be inspected is well known (for example, Patent Document 1). The image acquisition apparatus includes a plurality of pairs of two rollers that sandwich the reference surface in the vertical direction, that is, from the direction perpendicular to the reference surface described above. And these rollers convey this to-be-inspected medium along a reference plane by conveying in the state which pinched | interposed the to-be-inspected medium. These rollers are arranged so as to sandwich both ends of the medium to be inspected in the arrangement direction of the light receiving sensors before and after the medium to be inspected passes under the light receiving sensor array. For this purpose, a plurality of pairs of rollers are arranged before and after the light receiving sensor array in the transport direction. As a result, the medium to be inspected is transported in a fixed state along the reference plane when passing under the light receiving sensor array.

By the way, depending on the structure of the image acquisition device, the roller may not be provided in the above-described arrangement, that is, before and after the light receiving sensor array in the transport direction. In that case, for example, by providing a transport plate having a transport surface along the reference surface, and placing the medium to be inspected on the transport surface and transporting it, the medium to be inspected is in a state along the reference surface. The lower side of the light receiving sensor array is passed.
JP 2000-172898 A

  However, when fixing the medium to be inspected to the reference surface by the transport plate before and after the light receiving sensor array in the transport direction, unlike the case of fixing by the roller, the medium to be inspected is sandwiched from above and below. Since the medium to be inspected cannot be fixed to the surface, there is a possibility that so-called fluttering occurs such that the medium to be inspected partially floats on the reference surface and wrinkles occur. When such fluttering occurs, there is a difference between the respective light receiving sensors constituting the light receiving sensor array and the respective separation distances between the regions of the medium to be inspected corresponding to the respective light receiving sensors. As a result, a problem such as occurrence of unevenness occurs in the acquired image. For example, when the image acquisition device is used as the above-described determination device, the determination performance is deteriorated.

  Accordingly, an object of the present invention is to follow the reference plane when passing the medium to be inspected below the light receiving sensor array, even if the rollers cannot be provided in the front and rear in the conveyance direction of the light receiving sensor array. An object of the present invention is to provide an image acquisition device that can prevent flapping by fixing.

  In order to achieve the above object, according to the present invention, the image acquisition device has the following features.

That is, the image acquisition device according to the present invention includes a light receiving unit including a light receiving sensor array and a transport plate having a transport surface facing the light receiving surface of the light receiving sensor array. The light receiving sensor array includes a plurality of light receiving sensors arranged in an array in a direction perpendicular to the transport direction of the medium to be inspected transported on the transport surface of the transport plate, and from the light source Light emitted and reflected from the medium to be inspected is received. In addition, the light receiving unit includes a suppression mechanism that is configured by a linear body that causes the medium to be inspected that passes under the light receiving unit to adhere to the transport surface with a pressure that can be moved.

  In the image acquisition device according to the present invention, the light receiving unit including the light receiving sensor array includes a suppression mechanism. And by this suppression mechanism, the to-be-inspected medium which passes under a light-receiving part is closely_contact | adhered with the pressure which can move on a conveyance surface. Therefore, the medium to be inspected is transported under the light receiving unit in a state of being fixed along the transport surface from the vertical direction, that is, the direction perpendicular to the transport surface, by the suppression mechanism and the transport plate. Therefore, in the image acquisition device according to the present invention, even when the rollers cannot be provided before and after the light receiving sensor array in the transport direction, the above-described flapping can be prevented, and as a result, the acquired image is uneven. It can be prevented from occurring.

  Hereinafter, an image acquisition device according to an embodiment of the present invention will be described with reference to the drawings. Each drawing merely schematically shows the shape, size, and arrangement relationship of each component to the extent that the present invention can be understood. Therefore, the configuration of the present invention is not limited to the illustrated configuration example.

<First Embodiment>
In the first embodiment, an image acquisition device including a suppression mechanism configured by a linear body in the form of a circle or an ellipse ring will be described.

  FIGS. 1A and 1B are diagrams schematically showing a main part of an image acquisition apparatus according to the first embodiment of the present invention. FIG. 1B is a cross-sectional view of the cross section taken along the line I-I shown in FIG.

  The image acquisition apparatus according to the first embodiment includes a light receiving unit 13 including a light receiving sensor array 11, a light source 21, and a transport plate 17 that mounts and transports a medium to be inspected 15.

  The image acquisition apparatus according to the first embodiment acquires an image of the inspection surface 15a of a flat inspection target medium 15 such as banknotes, checks, securities, and the like conveyed along a horizontally set reference surface. To be used. Therefore, in the first embodiment, by providing the transport surface 17a of the transport plate 17 on which the inspection medium 15 is placed so as to coincide with the reference surface, the inspection medium 15 is horizontally aligned along the reference surface. Transport to. In addition, the conveyance direction of the to-be-inspected medium 15 is shown by the arrow in FIG. 1 (A) and (B).

  Further, the medium to be inspected 15 is conveyed by a conveying means such as a known roller. In the case of the configuration example shown in FIG. 1A, for example, a roller (not shown) is provided on the right side of the paper surface, and a part of the medium 15 to be inspected from above and below, that is, a direction perpendicular to the surface 15a to be inspected. Carry it in between.

  The light receiving unit 13 includes a light receiving sensor array 11 for receiving light emitted from a light source 21 to be described later and reflected from the inspection medium 15.

  The light receiving sensor array 11 includes a plurality of light receiving sensors 19 arranged in an array in a direction perpendicular to the transport direction of the medium 15 to be inspected and in parallel to the reference surface, that is, the transport surface 17a. 1A and 1B show a configuration example in which five light receiving sensors 19a, 19b, 19c, 19d, and 19e are arranged in an array.

  The light receiving sensor array 11 includes a light receiving surface 11a of the light receiving sensor array 11, that is, each light receiving surface 19aa, 19ba, 19ca, 19da, and 19ea of each light receiving sensor 19 constituting the light receiving sensor array 11. The surfaces 19aa to 19ea may be referred to as facing the transport surface 17a.

  Here, in the image acquisition apparatus according to the first embodiment, the entire inspection medium 15 or a part of the region to be inspected is located on the lower side of the light receiving sensor array 11, that is, each light receiving surface 19 aa of each light receiving sensor 19. The inspected medium 15 is transported so as to pass through a region 20 (hereinafter also simply referred to as a “facing region 20”) where ˜19ea is facing. 1A and 1B, the light receiving surface 19aa of the light receiving sensor 19a is a facing region 20a, the light receiving surface 19ba of the light receiving sensor 19b is a facing region 20b, and the light receiving surface of the light receiving sensor 19c. Reference numeral 19ca faces the facing area 20c, the light receiving surface 19da of the light receiving sensor 19d faces the facing area 20d, and the light receiving surface 19ea of the light receiving sensor 19e faces the facing area 20e. 1A and 1B, a configuration in the case where optical information is obtained from a part of the inspection medium 15, that is, a part of the inspection medium 15 passes through the facing area 20. An example is shown.

  The light receiving sensor array 11 is connected to the inspection medium 15 existing in the facing area 20 of each light receiving surface 19aa to 19ea of each light receiving sensor 19 when the medium 15 to be inspected passes below the light receiving sensor array 11. The reflected light is received to obtain optical information. Then, the inspection medium 15 is conveyed at a constant speed, and optical information from the inspection medium 15 existing in each facing area 20 of the light receiving surfaces 19aa to 19ea at each time point is received by the light receiving sensor array 11 at predetermined time intervals. get. Thereby, an image of the inspection medium 15 passing under the light receiving sensor array 11 is acquired. In the image acquisition apparatus according to the first embodiment, the optical information obtained from the light receiving sensor array 11 is converted into, for example, an MPU (microprocessor unit) and a memory via a known light receiving circuit and an A / D converter. An image is acquired by connecting to a data processing device (not shown). The light receiving circuit and the A / D converter amplify the optical information received by the light receiving sensor array 11 by the light receiving circuit, convert it to digital data by the A / D converter, and input it to the data processing device. Further, the data processing apparatus performs image processing on the optical information input as digital data, and stores the image processed data.

  The light source 21 is, for example, an LED, a fluorescent lamp, or other conventionally known light-emitting element, and is configured to emit beam-like emitted light. In the image acquisition apparatus according to the first embodiment, the light source 21 irradiates light onto the inspection surface 15a of the inspection target medium 15 being conveyed.

  If the light source 21 can emit light to the inspection medium 15 and the emitted light can be reflected by the inspection medium 15 at an angle at which the light receiving sensor array 11 can receive light, The arrangement location and the number of arrangement can be arbitrarily determined according to the design. In the configuration example of FIGS. 1A and 1B, a plurality of light receiving sensors 19 are arranged along the arrangement direction, and the rear side surface in the transport direction along the arrangement direction of the light receiving sensors 19 of the light receiving unit 13. It is arranged adjacent to 13b.

  Furthermore, in the first embodiment, the light receiving unit 13 includes a suppression mechanism 23.

  The suppression mechanism 23 is provided for the purpose of bringing the medium to be inspected 15 into close contact with the pressure that can be moved onto the conveying surface 17a when the medium to be inspected 15 passes under the light receiving unit 13. As a result, in the first embodiment, the inspected medium 15 is moved along the set reference surface, that is, the transport surface 17a from the vertical direction, that is, the direction perpendicular to the transport surface, by the suppression mechanism 23 and the transport plate 17. In a fixed state, the light passes through the facing area 20 of the light receiving surfaces 19aa to 19ea of the light receiving sensor 19 below the light receiving sensor array 11, that is, the light receiving sensors 19.

  In order to achieve the purpose of this close contact, in the first embodiment, the suppression mechanism 23 is composed of two linear bodies 25 in the form of two circular or elliptical rings. In the configuration example of FIGS. 1A and 1B, the linear body constituting the suppression mechanism 23 is shown as an elliptical ring.

  In 1st Embodiment, the linear body 25 used as the suppression mechanism 23 is comprised, for example using the piano wire, the metal wire, etc. as a material. Then, by providing the linear body 25 in the form of this ring, with respect to the inspection medium 15 passing under the light receiving unit 13, from the inspection surface 15a side of the inspection medium 15 in the direction perpendicular to the transport surface 17a. Pressure is applied. As a result, the inspected medium 15 passing under the light receiving unit 13 is sandwiched between the suppression mechanism 23 and the inspected surface 15a under the light receiving unit 13, so that the above-described fluttering does not occur and the lower side of the light receiving sensor array 11 is generated. Pass through.

  Further, the suppression mechanism 23 prevents light received on the light receiving surface 11a of the light receiving sensor array 11, that is, the light receiving surfaces 19aa to 19ea of each light receiving sensor 19, so as not to interfere with the optical information acquired by the light receiving sensor array 11. Outside the optical path, it is connected to the light receiving unit 13. For this purpose, the suppression mechanism 23 is connected to an outer part of the light receiving unit 13 where the light receiving sensor array 11 is provided.

  And in 1st Embodiment, the area | region which passes the lower side of the photosensor array 11 of the to-be-inspected medium 15 out of the optical path of the light received by such a light-receiving surface 11a, ie, a favorable balance. In order to hold the medium 15 to be inspected on the transport plate 17 with a balance that can suppress fluttering over the entire surface, the linear bodies 25 in the form of two rings are disposed at both ends of the light receiving unit 13 in the arrangement direction of the light receiving sensors 19. The suppression mechanism 23 is preferably provided in a state where the light receiving portions 13 are respectively passed through the rings. In the first embodiment, the light source 21 is adjacent to the light receiving unit 13 on the rear side surface 13b in the transport direction along the arrangement direction of the light reception sensors 19, and along the arrangement direction of the light reception sensors 19. Are arranged. In that case, it is preferable to provide the suppression mechanism 23 in a state where both ends of the light receiving unit 13 including the light source 21 are passed through the ring. In this case, of course, the suppression mechanism 23 is disposed outside the optical path of the reflected light received by each of the light receiving surfaces 19aa to 19ea and outside the optical path of the outgoing light emitted from the light source 21. It is preferable to do this.

  The suppression mechanism 23 is connected to the light receiving unit 13 using, for example, a well-known adhesive, solder, or the like.

  Here, in the first embodiment, the suppression mechanism 23 moves the medium 15 to be inspected by the suppression mechanism 23 so that the medium 15 can be moved onto the transport surface 17a, that is, without interfering with the transport. It is necessary to set the pressure to suppress suitably. Therefore, in the first embodiment, the medium to be inspected 15 at each separation distance W1 while changing the separation distance W1 between the contact portion 25a of the linear body 25 with the medium to be inspected 15 and the conveyance surface 17a. Test to actually transport. From this test, the separation distance W1 is determined experimentally such that the medium 15 to be inspected is in close contact with the conveyance surface 17a and the suppression mechanism 23 can pass under the light receiving unit 13 without delaying conveyance. Then, with the separation distance W1 determined experimentally in this way, the medium to be inspected 15 of the suppression mechanism 23 according to the thickness and mass of, for example, banknotes, securities, checks, etc., assumed as the medium to be inspected 15 Set the pressure to hold down.

  In the image acquisition device according to the first embodiment, the light receiving unit 13 including the light receiving sensor array 11 includes a suppression mechanism 23 configured by linear bodies 25 in the form of two rings. And by this suppression mechanism 23, the to-be-inspected medium 15 which passes under the light-receiving part 13 is closely_contact | adhered with the pressure which can move on the conveyance surface 17a. Therefore, under the light receiving unit 13, the medium 15 to be inspected is fixed along the set reference surface, that is, the transport surface 17a from the vertical direction, that is, the direction perpendicular to the transport surface 17a, by the suppression mechanism 23 and the transport plate 17. It is conveyed in the state. Therefore, in the image acquisition device according to the first embodiment, even when the rollers cannot be provided before and after the light receiving sensor array 11 in the transport direction, the suppression mechanism 23 prevents the above-described flapping. As a result, it is possible to prevent unevenness in the acquired image.

<Second Embodiment>
In the second embodiment, an image acquisition apparatus including a suppression mechanism configured with a J-shaped linear body will be described.

  The image acquisition device according to the second embodiment is different from the image acquisition device according to the first embodiment described above in that the suppression mechanism is composed of a plurality of J-shaped linear bodies. . Since other components and operational effects are the same as those of the first embodiment described above, common components are denoted by the same reference numerals, and redundant description thereof is omitted.

  FIGS. 2A and 2B are diagrams schematically showing a main part of an image acquisition apparatus according to the second embodiment of the present invention. FIG. 2B is a cross-sectional view taken along the line II-II shown in FIG.

  In the image acquisition device according to the second embodiment, the light receiving unit 13 includes a suppression mechanism 27. Similar to the suppression mechanism 23 according to the first embodiment described above, the suppression mechanism 27 moves the inspection medium 15 on the conveyance surface 17a when the inspection medium 15 to be conveyed passes under the light receiving unit 13. It is provided for the purpose of bringing it into close contact with a movable pressure. As a result, in the second embodiment, similarly to the first embodiment described above, the medium to be inspected 15 is moved vertically by the suppression mechanism 23 and the transport plate 17, that is, from the direction perpendicular to the transport surface. In a state of being fixed along the set reference surface, that is, the conveyance surface 17a, the light passes through the facing region 20 on the lower side of the light receiving sensor array 11, that is, on the light receiving surfaces 19aa to 19ea of each light receiving sensor 19.

  In order to achieve the purpose of this close contact, in the second embodiment, the suppression mechanism 27 includes a plurality of connecting portions 29a and a J-shaped linear body including a curved portion 29b extending from the connecting portion 29a. 29.

  In the second embodiment, as in the first embodiment described above, the J-shaped linear body 29 used as the suppression mechanism 27 is made of, for example, a piano wire, a metal wire, or the like. By providing the J-shaped linear body 29, pressure is applied from the inspection surface 15a side of the inspection medium 15 to the inspection medium 15 passing under the light receiving unit 13 in a direction perpendicular to the transport surface 17a. Will be added. As a result, the inspected medium 15 passing under the light receiving unit 13 is sandwiched between the suppression mechanism 27 and the inspected surface 15a under the light receiving unit 13, so that the above-described fluttering does not occur and the lower side of the light receiving sensor array 11 is generated. Pass through.

  Further, the suppression mechanism 27 is similar to the first embodiment described above, so that the optical information acquired by the light receiving sensor array 11 is not hindered, that is, the light receiving surface 11 a of the light receiving sensor array 11, that is, each light receiving sensor 19. The light receiving surfaces 19aa to 19ea are connected to the light receiving unit 13 outside the optical path of the light received. For this purpose, the suppression mechanism 27 is connected to the side surface 13a or 13b of the light receiving unit 13 in the connecting portion 29a of the J-shaped linear body 29, which is perpendicular to the conveying surface 17a and along the arrangement direction of the light receiving sensors 19. . Then, the curved portion 29b provided to hold the inspection medium 15 as the inspection medium 15 exists outside the optical path of the light received by the light receiving surfaces 19aa to 19ea of the respective light receiving sensors 19. Is arranged.

  In the second embodiment, the light received by the light receiving surface 11a is outside the optical path and has a good balance, that is, the region passing through the lower side of the light receiving sensor array 11 of the medium 15 to be inspected. In order to hold the medium 15 to be inspected on the transport plate 17 with a balance that can suppress fluttering on the entire surface, the light receiving unit 13 is moved in the arrangement direction of the light receiving sensors 19 perpendicular to the transport surface 17a by a plurality of linear bodies 29. It is preferable to arrange it between both side surfaces 13a and 13b along. In FIGS. 2A and 2B, the suppression mechanism 27 is composed of two linear bodies 29 at each of the three ends of the light receiving unit 13 in the arrangement direction of the light receiving sensor 19 and the light receiving unit. The example of a structure which has arrange | positioned 13 on both sides 13a and 13b is shown.

  In the second embodiment, similarly to the first embodiment described above, the light source 21 is placed on the light receiving unit 13 and the rear surface 13b in the transport direction along the arrangement direction of the light receiving sensors 19 is used. A plurality of the light receiving sensors 19 are arranged adjacent to each other along the arrangement direction of the light receiving sensors 19. In that case, it is preferable to provide the suppression mechanism 27 so as to be sandwiched from both side surfaces 13 a and 13 b of the light receiving unit 13 with the light source 21 therebetween. In this case, of course, the suppression mechanism 27 is disposed outside the optical path of the reflected light received by each of the light receiving surfaces 19aa to 19ea and outside the optical path of the outgoing light emitted from the light source 23. It is preferable to do this.

  Moreover, the suppression mechanism 27 is connected to the light receiving unit 13 using, for example, a well-known adhesive, solder, or the like, as in the first embodiment described above.

  And in 2nd Embodiment, in order to make the to-be-inspected medium 15 move on the conveyance surface 17a by the suppression mechanism 27 similarly to 1st Embodiment mentioned above, ie, to contact | adhere without disturbing conveyance. A test for actually transporting the inspection medium 15 at each separation distance W2 is performed while changing the separation distance W2 between the contact portion 29c of the linear body 29 with the inspection medium 15 and the transport surface 17a. From this test, the separation distance W2 is determined experimentally such that the medium 15 to be inspected is in close contact with the conveyance surface 17a and the suppression mechanism 27 can pass under the light receiving unit 13 without being delayed. Then, with the separation distance W2 determined experimentally in this way, the medium to be inspected 15 of the suppression mechanism 27 according to the thickness and mass of, for example, banknotes, securities, checks, etc., assumed as the medium to be inspected 15 Set the pressure to hold down.

  In the image acquisition apparatus according to the second embodiment, a J-shaped linear body 29 is used as the suppression mechanism 27. Therefore, unlike the first embodiment in which a linear body in the form of a ring is used as the suppression mechanism, the J-shaped curved portion 29b is arranged away from the optical path of the light received by each of the light receiving surfaces 19aa to 19ea. Thus, the entire suppression mechanism 27 can be disposed outside this optical path. Therefore, in the image acquisition device according to the second embodiment, the location where the suppression mechanism 27 is connected is not limited to only both ends of the light receiving unit 13 in the arrangement direction of the light receiving sensors 19. Therefore, in the second embodiment, a suitable number of linear bodies 29 corresponding to the thickness and mass of the medium 15 to be inspected and the area of the region to be inspected are used as the suppression mechanism 27 in the arrangement direction of the light receiving sensors 19. Can be connected to suitable locations on both side faces 13a and 13b. As a result, in the image acquisition device according to the second embodiment, in preventing the flutter described above, the inspected medium 15 is arranged with a better balance of arrangement compared to the image acquisition device according to the first embodiment. I can hold it down.

<Third Embodiment>
In the third embodiment, an image acquisition apparatus including a cover that covers a light receiving surface of a light receiving sensor array will be described as a suppression mechanism.

  The image acquisition device according to the third embodiment is different from the image acquisition devices according to the first and second embodiments described above in that the suppression mechanism is a cover that covers the light receiving surface of the light receiving sensor array. is there. Since other components and operational effects are the same as those of the first and second embodiments described above, common components are denoted by the same reference numerals, and redundant description thereof is omitted.

  FIGS. 3A and 3B are diagrams schematically showing a main part of an image acquisition apparatus according to the third embodiment of the present invention. FIG. 3B is a cross-sectional view of the cross section taken along the line III-III shown in FIG.

  In the image acquisition device according to the third embodiment, the light receiving unit 13 includes a suppression mechanism 31. In the suppression mechanism 31, similarly to the suppression mechanism 23 according to the first embodiment and the suppression mechanism 27 according to the second embodiment, the medium to be inspected 15 passes under the light receiving unit 13. At this time, it is provided for the purpose of bringing the medium to be inspected 15 into close contact with the pressure that can be moved onto the transport surface 17a. As a result, in the third embodiment, similarly to the first and second embodiments described above, the medium to be inspected 15 is moved vertically by the suppression mechanism 31 and the transport plate 17, that is, perpendicular to the transport surface. From the direction, in a state of being fixed along the set reference surface, that is, the transport surface 17a, the light passes through the facing region 20 on the lower side of the light receiving sensor array 11, that is, on the light receiving surfaces 19aa to 19ea of each light receiving sensor 19. .

  In order to achieve the purpose of this close contact, in the third embodiment, the suppression mechanism 31 has a semicircular, semi-elliptical shape, or a shape that tapers as it approaches the conveyance surface 17a. It is a cover and is provided so as to cover the light receiving surface 11 a of the light receiving sensor array 11. 3A and 3B show the case where the suppression mechanism 31 is a cover having a semi-elliptical cut along the conveyance direction.

  In the third embodiment, by providing a cover as the suppression mechanism 31, the medium to be inspected 15 is inspected in a direction perpendicular to the transport surface 17 a with respect to the medium to be inspected 15 passing under the light receiving unit 13. Pressure is applied from the surface 15a side. As a result, the inspected medium 15 passing under the light receiving unit 13 is sandwiched between the suppression mechanism 31 and the inspected surface 15a under the light receiving unit 13, so that the above-described fluttering does not occur and the lower side of the light receiving sensor array 11 is generated. Pass through.

  In the third embodiment, similarly to the first and second embodiments described above, the cover used as the suppression mechanism 31 is not covered so as not to interfere with the optical information acquired by the light receiving sensor array 11. It is made of a material that can transmit reflected light from the inspection medium 15, that is, a light-transmitting material. In the third embodiment, the cover is formed of translucent glass, plastic, or other suitable material according to the design.

  In the third embodiment, the medium 15 to be inspected is transported with a good balance, i.e., a balance that can suppress fluttering in the entire area of the area under the photosensor array 11 of the medium to be inspected 15. 17, it is preferable to provide the light receiving unit 13 with a cover that covers the entire light receiving surface 11 a of the light receiving sensor array 11 as the suppression mechanism 31. Depending on the mass and thickness of the medium 15 to be inspected and the area of the region to be inspected, a plurality of covers that partially cover the light receiving surface 11 a are arranged as the suppression mechanism 31 along the arrangement direction of the light receiving sensors 19. They may be provided apart from each other. 3A and 3B show a configuration example in the case where a cover that covers the entire light receiving surface 11a of the light receiving sensor array 11 is provided as the suppression mechanism 31 in the light receiving unit 13. FIG.

  In addition, the suppression mechanism 31 is connected to the light receiving unit 13 using, for example, a known adhesive, solder, or the like, as in the first and second embodiments described above.

  In the third embodiment, similarly to the first and second embodiments described above, the restraint mechanism 31 allows the medium 15 to be inspected to be moved on the transport surface 17a, that is, without interfering with transport. Therefore, a test for actually transporting the inspection medium 15 at each separation distance W3 while changing the separation distance W3 between the contact portion 31a of the cover as the suppression mechanism 31 with the inspection medium 15 and the transport surface 17a. Do. From this test, a separation distance W3 is experimentally determined such that the medium 15 to be inspected is in close contact with the transport surface 17a and can be passed under the light receiving unit 13 without being transported by the suppression mechanism 31. Then, with the separation distance W3 determined experimentally in this way, the medium to be inspected 15 of the suppression mechanism 31 corresponding to the thickness and mass of, for example, banknotes, securities, checks, etc., assumed as the medium to be inspected 15 Set the pressure to hold down.

  In the image acquisition device according to the third embodiment, the suppression mechanism 31 is a cover having a semicircular, semi-elliptical, or tapered shape that cuts in the direction of conveyance along the conveyance surface 17a, and transmits light. It has a cover made of sex material. In the image acquisition apparatus according to the third embodiment, a cover as the suppression mechanism 31 is provided on the light receiving unit 13 so as to cover the light receiving surface 11 a of the light receiving sensor array 11.

  For this reason, in the image acquisition device according to the third embodiment, the cover as the suppression mechanism 31 covers the light receiving surface 11a of the light receiving sensor array 11 so that the light receiving sensor array 11 has a light receiving surface 11a. The to-be-inspected medium 15 that passes through the facing region 20 of the surfaces 19aa to 19ea can be pressed down by the suppression mechanism 31 entirely. As a result, in the image acquisition device according to the third embodiment, in preventing the flutter described above, the inspected with a better arrangement balance than the image acquisition devices according to the first and second embodiments. The medium 15 can be pressed.

FIGS. 1A and 1B are diagrams schematically showing a main part of an image acquisition apparatus according to a first embodiment of the present invention. FIG. 1B is a diagram showing an I shown in FIG. It is sectional drawing which looked at the cross section cut along the -I line | wire from the arrow direction. FIGS. 2A and 2B are diagrams schematically showing a main part of an image acquisition apparatus according to a second embodiment of the present invention, and FIG. 2B is a diagram II shown in FIG. It is sectional drawing which looked at the cross section cut along the -II line from the arrow direction. FIGS. 3A and 3B are diagrams schematically showing a main part of an image acquisition apparatus according to a third embodiment of the present invention, and FIG. 3B is a diagram showing III shown in FIG. It is sectional drawing which looked at the cross section cut along the -III line from the arrow direction.

Explanation of symbols

11: Light receiving sensor array 13: Light receiving unit 15: Medium to be inspected 17: Transport plate 19: Light receiving sensor 20: Directly facing area 21: Light source 23, 27, 31: Suppression mechanism 25, 29: Linear body

Claims (3)

A light receiving unit including a light receiving sensor array;
A transport plate having a transport surface facing the light receiving surface of the light receiving sensor array;
The light receiving sensor array includes a plurality of light receiving sensors arranged in an array in a direction perpendicular to a transport direction of a medium to be inspected transported on the transport surface of the transport plate, and a light source Receiving the light emitted from and reflected from the inspected medium,
The image acquisition device, wherein the light receiving unit includes a suppression mechanism configured by a linear body that causes the medium to be inspected that passes under the light receiving unit to adhere to the transport surface with pressure that can be moved. . The image acquisition device according to claim 1,
The suppression mechanism, two, a the linear body in the form of a circle or ellipse ring,
The light receiving sensor is connected to the light receiving unit at both ends in the arrangement direction of the light receiving sensor, with the light receiving unit passing through the ring, and outside the optical path of the light received by the light receiving surface. A characteristic image acquisition device. The image acquisition device according to claim 1,
The suppression mechanism has a plurality of, a the linear body of J-shaped,
The light receiving unit is sandwiched from both side surfaces along the arrangement direction of the light receiving sensors perpendicular to the transport surface, and is connected to the light receiving unit outside the optical path of the light received by the light receiving surface. An image acquisition device.

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