JP5953589B2 - Paper feeder - Google Patents

Description

  The present invention relates to a sheet feeding device, and more particularly, to a sheet feeding device including an ultrasonic multifeed sensor.

  When feeding sheets one by one from the stacked sheets, double feeding may occur. Appropriate detection of this double feed is extremely important in the quality of the paper feeder. For this double feed detection, an optical double feed sensor that detects double feed based on the amount of light received by the light receiving sensor may be used. However, in a paper feeder that mainly feeds paper on which an image has already been recorded, such as a newspaper advertisement, it may be difficult to detect double feed based on the amount of received light. In such a case, an ultrasonic sensor in which an ultrasonic oscillator and a geophone are arranged across the paper conveyance path is effective for detecting the multifeed.

  However, when an ultrasonic sensor is used for double feed detection, there is a possibility that erroneous detection may occur due to external noise. On the other hand, when a plurality of ultrasonic sensors are provided corresponding to a plurality of paper feed shelves, a technique has been proposed that enables switching between shelves that notify double feeding and shelves that are not notified for each shelf (for example, Patent Document 1).

JP 2011-168400 A

  Some paper feeding devices are provided with a plurality of paper feeding shelves. In this case, a plurality of ultrasonic sensors are provided corresponding to each of the plurality of paper feed shelves. When such multi-feed detection is performed in such a sheet feeding device, interference due to ultrasonic waves generated from the ultrasonic sensors of other sheet feeding shelves occurs, resulting in erroneous detection. In the above-mentioned Patent Document 1, a technique for switching a shelf for notifying a double feed and a shelf for which no notification is made for each shelf is described. In order to solve the above problem, the frequency of each sensor between adjacent shelves is set. Since it corresponds to not changing, modulating the output, or shifting the position, complicated structure and control are required. Further, even when these measures are introduced, it is difficult to eliminate erroneous detection when simultaneously feeding sheets from a plurality of sheet feeding mechanisms.

  The present invention has been made in view of such problems, and an object thereof is to reduce erroneous detection of double feeding using an ultrasonic sensor.

In order to solve the above problems, a sheet feeding device according to an aspect of the present invention is provided corresponding to each of a plurality of sheet feeding shelves, and a plurality of sheet feeding units that respectively feed sheets from the corresponding sheet feeding shelves to a sheet conveyance path. When there is a mechanism and a plurality of paper feed mechanisms, an oscillator that oscillates ultrasonic waves, and a geophone that is placed across the oscillator and the paper transport path, and the paper passes through the paper transport path Corresponds to multiple ultrasonic sensors and multiple ultrasonic sensors that respectively detect double feed when paper is sent out from the corresponding paper feed mechanism based on the ultrasonic waveform received by the geophone and provided, the corresponding ultrasonic sensor geophone sheet conveyance downstream vicinity arranged plate-shaped sound absorbing material of the includes a sheet conveyance direction upstream side of the periphery of the receiving shakers communicates with the external space It is .
Also, another aspect of the sheet feeding apparatus of the present invention are provided corresponding to the plurality of sheet feeding shelves, a plurality of paper feed mechanism for feeding the corresponding sheet feeding shelf paper to the paper conveying plate respectively, An oscillator that oscillates an ultrasonic wave and is placed in correspondence with each of a plurality of paper feeding mechanisms, and a vibrator that is disposed across the oscillator and the paper transport path, and when the paper passes through the paper transport path Provided corresponding to any of a plurality of ultrasonic sensors and a plurality of ultrasonic sensors for detecting double feeding when paper is fed out from the corresponding paper feeding mechanism based on the ultrasonic waveform received by A plate-like sound absorbing material disposed near the downstream side of the paper conveyance of the corresponding ultrasonic sensor geophone, and a space through which the paper passes, with the paper conveyance plate as the lower end and at least a part of the sound absorbing material as the upper end And having.
The sheet feeding device according to another aspect of the present invention is provided corresponding to each of a plurality of sheet feeding shelves, and includes a plurality of sheet feeding mechanisms that respectively feed sheets from the corresponding sheet feeding shelves to a sheet conveyance path, and a plurality of sheet feeding mechanisms. Each of the paper feed mechanisms has an oscillator that oscillates ultrasonic waves and a geophone that is placed across the oscillator and the paper conveyance path. When the paper passes through the paper conveyance path, the vibration is received by the geophone. A plurality of ultrasonic sensors for detecting double feeding when the paper is sent out from the corresponding paper feeding mechanism based on the waveform of the ultrasonic wave, and provided corresponding to any of the plurality of ultrasonic sensors; A plate-like sound absorbing material disposed in the vicinity of the paper conveyance downstream side of the corresponding ultrasonic sensor geophone, and both sides in the direction perpendicular to the paper conveyance direction of the sound absorption material on the paper conveyance downstream side of the paper feed mechanism And is fed from the paper feed mechanism Further with feeding the sheet conveyance downstream side sheet comprises a shroud disposed to surround the geophones with sound absorbing material, the.

  In many cases, a sheet feeding shelf or the like exists on the upstream side of the sheet conveyance of the ultrasonic sensor geophone, and is widely open to the external space. On the other hand, there are usually many components on the downstream side of the sheet conveyance of the ultrasonic sensor geophone. For this reason, when a plurality of ultrasonic sensors are provided, the ultrasonic waves oscillated from other ultrasonic sensors mainly reach and interfere from the downstream side of the paper conveyance of the geophone, which is a cause of erroneous detection. Is likely. According to this aspect, ultrasonic waves that interfere with the geophone from the downstream side of the sheet conveyance can be suppressed.

A sheet feeding device according to another aspect of the present invention is provided corresponding to each of a plurality of sheet feeding shelves, and includes a plurality of sheet feeding mechanisms that respectively feed sheets from the corresponding sheet feeding shelves to a sheet conveyance path, and a plurality of sheet feeding units. Each of the mechanisms is provided with an oscillator that oscillates an ultrasonic wave and a geophone that is disposed across the oscillator and the paper conveyance path, and is received by the geophone when the paper passes through the paper conveyance path. A plurality of ultrasonic sensors that respectively detect double feeding when paper is sent out from the corresponding paper feeding mechanism based on the waveform of the ultrasonic wave, and a plurality of ultrasonic sensors are provided correspondingly. A plate-shaped sound absorbing material disposed near the paper conveyance downstream side of the ultrasonic sensor geophone and a paper conveyance mechanism provided downstream of the paper conveyance mechanism, and further feeding the paper fed from the paper supply mechanism further to the paper conveyance downstream side. A pair of rollers for feeding Sound absorbing material is disposed between the pair of rollers, surrounding the geophone with a pair of rollers.

As a result of the inventor's earnest research and development, the sound absorbing material is arranged between the pair of rollers as described above, and the vibration receiving device is surrounded by the pair of rollers and the sound absorbing material. It has been found that interference can be suppressed. Therefore, according to this aspect, it is possible to appropriately suppress erroneous detection of double feeding due to ultrasonic interference.

You may further provide the elastic film arrange | positioned so that it may overlap with a sound-absorbing material. According to this aspect, it is possible to suppress ultrasonic waves that cannot be sufficiently absorbed by the sound absorbing material among the external ultrasonic waves received by the geophone. For this reason, erroneous detection of double feeding can be appropriately suppressed.

Intake sound material, provided with at least correspond to the ultrasonic sensor for detecting the double feed of the paper feed mechanism oscillator corresponding to the paper feed mechanism in which the adjacent than the paper conveyance path of the paper feed mechanism adjacent located near Also good.

As a result of the inventor's diligent research and development, for example, in a paper feeding device in which an oscillator is disposed below with a geophone and a paper conveyance path interposed, an oscillator from an oscillator provided corresponding to the upper adjacent paper feeding mechanism is used. It was found that interference was caused by sound waves. Further, it has been found that when the arrangement of the oscillator and the geophone is turned upside down, interference occurs due to the ultrasonic wave from the oscillator provided corresponding to the paper feeding mechanism adjacent below. Therefore, according to this aspect, it is possible to appropriately suppress the interference caused by the ultrasonic waves oscillated from the oscillator of the ultrasonic sensor corresponding to the adjacent paper feeding mechanism.

  According to the present invention, it is possible to reduce erroneous detection of double feeding using an ultrasonic sensor.

It is a front view of the paper feeder concerning this embodiment. It is a figure which shows a paper feeding mechanism and its periphery. FIG. 3 is a view of a sheet feeding mechanism viewed from a viewpoint P in FIG. 2. It is a figure which shows the detection signal of an ultrasonic sensor when a 1st sound-absorbing material unit is removed. It is a figure which shows the detection signal of an ultrasonic sensor when a 1st sound-absorbing material unit is attached. Detection of the geophone of the first-stage ultrasonic sensor when ultrasonic waves are oscillated from the ultrasonic sensor oscillator only in the uppermost (first-stage) paper feed shelf and the lower (second-stage) paper feed shelf. It is a figure which shows a result. It is a figure which shows the detection result of the geophone of a 2nd level ultrasonic sensor when an ultrasonic wave is oscillated from the oscillator of an ultrasonic sensor only in the 1st level paper supply shelf and the 2nd level paper supply shelf. It is a figure which shows the detection result of the geophone of an ultrasonic sensor when the 1st sound absorption material which concerns on this embodiment is used. It is a figure which shows the detection result of the geophone of an ultrasonic sensor when it replaces with a 1st sound absorption material and the sound absorption material (henceforth a "short sound absorption material") which has a width substantially the same as the width of an ultrasonic sensor is used. is there.

  Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings.

  FIG. 1 is a front view of a sheet feeding device 10 according to the present embodiment. In order to facilitate understanding, FIG. 1 shows the internal structure of the sheet feeding device 10. The sheet feeding device 10 includes a main body 12, a multistage sheet feeding mechanism 14, and a horizontal transport mechanism 16. The main body 12 has a casing that is long in the vertical direction. The horizontal transport mechanism 16 is disposed below the inside of the main body 12. The horizontal transport mechanism 16 includes a belt and paper feed rollers extending in the horizontal direction, and transports the paper transported from the multi-stage paper feed mechanism 14 in the horizontal direction.

  The multistage sheet feeding mechanism 14 includes a plurality of sheet feeding shelves 20, a plurality of sheet feeding mechanisms 22, and a belt transport mechanism 24. The plurality of paper feed shelves 20 are arranged at intervals in the vertical direction. Each of the plurality of paper feed shelves 20 is disposed to be inclined to the left. In the present embodiment, ten paper feed shelves 20 are provided. Of course, the number of paper feed shelves 20 is not limited to ten.

  The plurality of sheet feeding mechanisms 22 are provided corresponding to the plurality of sheet feeding shelves 20, respectively. The paper feed mechanisms 22 are arranged around the left end portion of the corresponding paper feed mechanism 22, and each feeds paper from the corresponding paper feed shelf 20.

  The belt transport mechanism 24 is disposed further to the left of the paper feed mechanism 22. The belt conveyance mechanism 24 includes a belt 30, a tension roller 32, a conveyance roller 34, and a paper guide 36. The belt 30 extends over the entire length of the multi-stage sheet feeding mechanism 14 in the vertical direction. One tension roller 32 is provided above and below. The belt 30 is hung on the tension roller 32. The tension roller 32 gives the belt 30 an appropriate tension.

  The paper guide 36 is disposed on the right surface of the belt 30 with an interval, and guides the paper fed between the paper guide 36 and the belt 30. Therefore, between the belt 30 and the sheet guide 36 is a common conveyance path 38 through which the sheets fed from the plurality of sheet feeding mechanisms 22 are conveyed. In this common conveyance path 38, the sheets fed from the plurality of sheet feeding mechanisms 22 are overlapped and conveyed integrally as a sheet bundle. For this reason, the sheet feeding device 10 functions as a collating device.

  A pair of transport rollers 34 is arranged corresponding to each of the plurality of paper feed mechanisms 22. The pair of transport rollers 34 feeds the paper fed from the corresponding paper feed mechanism 22 to the common transport path 38.

  FIG. 2 is a diagram showing the paper feed mechanism 22 and its surroundings. The paper feed mechanism 22 has a paper separation mechanism 40. The paper separation mechanism 40 includes a paper feed roller 41, a pickup roller 42, a separation member 44, and a paper transport plate 46. The pickup roller 42 sends out the uppermost sheet among the sheets on the sheet conveying plate 46 between the sheet feeding roller 41 and the separating member 44. The paper feed roller 41 is disposed on the downstream side in the paper conveyance direction of the pickup roller 42 (hereinafter simply referred to as “downstream side”), and the separation member 44 is formed of a material having a high friction coefficient and elasticity such as rubber. It is disposed below the paper feed roller 41 so as to contact the roller 41. When a plurality of sheets sent out by the pickup roller 42 are overlapped, the sheet feeding roller 41 and the separating member 44 separate them and send out the uppermost sheet one by one. The paper separated and sent out by the paper feed roller 41 and the separating member 44 is transported on a substantially horizontal paper transport plate 46 and sent out to the paper bundle transport path 90 by a pair of horizontal transport rollers 88. Hereinafter, the paper passage path on the paper transport plate 46 is referred to as a paper transport path.

  The sheet feeding device 10 includes a plurality of double feed detection mechanisms 50 that detect double feed of the paper sent out by the paper separation mechanism 40. The double feed detection mechanism 50 includes an ultrasonic sensor 54, a first sound absorbing material unit 56, and a second sound absorbing material 58.

  One ultrasonic sensor 54 is provided for each of the plurality of paper feeding mechanisms 22. The ultrasonic sensor 54 has an oscillator 62 and a geophone 64. The oscillator 62 oscillates ultrasonic waves. The geophone 64 receives the ultrasonic wave oscillated by the oscillator 62. The geophone 64 is disposed so as to face the oscillator 62 across the paper conveyance path. In this embodiment, the oscillator 62 is disposed below the paper transport path, and the vibration receiving device 64 is disposed above the paper transport path. A second plate 52 is disposed on the downstream side of the paper feed roller 41. The geophone 64 is attached to the second plate 52.

  Further, the oscillator 62 is disposed on the downstream side of the geophone 64. For this reason, the ultrasonic wave oscillated from the oscillator 62 travels upward and obliquely rearward and is received by the geophone 64. Thus, by arranging the oscillator 62 and the geophone 64 obliquely, it is possible to suppress the sheet of paper to be transported and the ultrasonic wave reflected by the paper transport plate 46 and returning to the oscillator 62. The ultrasonic sensor 54 detects double feeding based on a difference in attenuation amount of ultrasonic waves between when a single sheet passes and when double feeding occurs.

  Here, when a plurality of ultrasonic sensors 54 are provided in one sheet feeding device 10 in this way, there is a possibility that ultrasonic waves generated by other ultrasonic sensors 54 are received and erroneous detection is performed. When a plurality of paper supply shelves 20 are arranged in the vertical direction as in the paper supply device 10, the ultrasonic sensor 54 is upstream of the ultrasonic sensor 54 (hereinafter simply referred to as “upstream side”), that is, the ultrasonic sensor 54. The right side communicates with the external space from between the paper feed shelves 20. Therefore, the ultrasonic wave oscillated from the ultrasonic sensor 54 is released to the external space as it is, and is unlikely to be reflected by any member and reach the vibration receiver 64 of another ultrasonic sensor 54.

  In contrast, on the downstream side of the ultrasonic sensor 54, that is, on the left side of the ultrasonic sensor 54, there are many parts such as the belt 30. For this reason, there is a possibility that the ultrasonic wave oscillated from the other ultrasonic sensor 54 is reflected by such a component and received by the vibration receiver 64 of the ultrasonic sensor 54. Further, since the common conveyance path 38 exists downstream from the ultrasonic sensor 54, ultrasonic waves oscillated from the other ultrasonic sensors 54 pass through the common conveyance path 38 to the geophone 64 of the ultrasonic sensor 54. There is also the possibility of passing through.

  In order to suppress interference by the other ultrasonic sensor 54 as described above, a second sound absorbing material 58 is provided below the geophone 64. The second sound absorbing material 58 is formed in a cylindrical shape in order to secure a region through which ultrasonic waves from the lower oscillator 62 pass. The second sound absorbing material 58 is made of urethane foam, silicon, nonwoven fabric, wool, or sponge. It is needless to say that the material of the second sound absorbing material 58 is not limited to this, and other ultrasonic absorbing materials having the ability to absorb ultrasonic waves may be used. However, as a result of the inventor's research and development, the cylindrical second sound absorbing material 58 alone cannot sufficiently absorb the ultrasonic waves from the other ultrasonic sensors 54, and there is a possibility that erroneous detection of double feeding may occur. It has been found.

  For this reason, in this embodiment, the 1st sound-absorbing material unit 56 is provided corresponding to each of the some ultrasonic sensor 54. FIG. The first sound absorbing material unit 56 includes a first sound absorbing material 66 and an elastic film 68. The common conveyance path 38 exists downstream of the ultrasonic sensor 54, and the first sound absorbing material 66 is disposed so as to be interposed between the oscillator 62 of the ultrasonic sensor 54 and the common conveyance path 38. Accordingly, the first sound absorbing material 66 is disposed in the vicinity of the downstream side of the sheet conveyance of the vibration receiving device 64 of the corresponding ultrasonic sensor 54.

  The first sound absorbing material 66 is formed in a flat plate shape having a rectangular outer shape. Of course, the shape of the first sound absorbing material 66 is not limited to this, and may be formed in a shape other than a rectangle or a curved plate shape. The first sound absorbing material 66 is formed of urethane foam, silicon, nonwoven fabric, wool, or sponge. Of course, the material of the first sound absorbing material 66 is not limited to this, and other ultrasonic absorbing materials having the ability to absorb ultrasonic waves may be used.

  The elastic film 68 is disposed so as to overlap the first sound absorbing material 66. The elastic film 68 is made of a material having higher specific gravity and rigidity than the first sound absorbing material 66, and functions as an ultrasonic reflecting material. The elastic film 68 is formed of a flexible resin. In the present embodiment, the elastic film 68 is fixed to the downstream surface of the first sound absorbing material 66 by adhesion. Thus, the first sound absorbing material unit 56 is formed by the first sound absorbing material 66 and the elastic film 68.

  A first plate 51 is disposed above the second plate 52. The first sound absorbing material unit 56 has an upper end attached to the first plate 51. At this time, the first sound absorbing material unit 56 is attached so that the elastic film 68 is positioned downstream of the first sound absorbing material 66. The second plate 52 has an inclined surface that descends toward the downstream side, and the first sound-absorbing material unit 56 is fixed against the inclined surface. Therefore, the first sound absorbing material unit 56 is disposed so as to be inclined downward toward the downstream side. By arranging the first sound absorbing material unit 56 so as to be inclined as described above, even when the fed paper hits the vicinity of the lower end of the first sound absorbing material unit 56, the paper can be guided downward. . The elastic film 68 may be provided on the upstream side of the first sound absorbing material 66. As a result, when the fed sheet floats upward and hits the vicinity of the lower end of the first sound absorbing material unit 56, the sheet can be smoothly guided downward by the elastic force. Further, the elastic film 68 may be attached to both surfaces of the first sound absorbing material 66.

  In the present embodiment, one first sound absorbing material unit 56 is provided for each of the paper feed shelves 20. The first sound absorbing material unit 56 may be provided corresponding to each of the paper feed shelves 20 other than at least the uppermost paper feed shelf 20 among the plurality of paper feed shelves 20. For example, the first sound absorbing material unit 56 corresponding to the uppermost sheet feeding shelf 20 may be deleted, and the first sound absorbing material unit 56 may be disposed corresponding to the sheet feeding racks 20 other than the uppermost sheet.

  As a result of research and development by the inventor, in the configuration of the ultrasonic sensor 54 in which the oscillator 62 is disposed below and the geophone 64 is disposed above, the ultrasonic wave oscillated from the ultrasonic sensor 54 corresponding to the upper paper feed shelf 20 is obtained. Interfering with the geophone 64 of the ultrasonic sensor 54 corresponding to the paper feed shelf 20 below. For this reason, the first sound absorbing material 66 detects an ultrasonic wave that detects the double feed of the paper feed mechanism 22 in which the oscillator 62 corresponding to the adjacent paper feed mechanism 22 is located closer to the paper feed path in the adjacent paper feed mechanism 22. It is provided corresponding to at least the sensor 54.

  Specifically, when a plurality of paper feed mechanisms 22 in which the oscillator 62 is disposed below the paper transport path and the geophone 64 is disposed above the paper transport path are arranged side by side, one of the paper feed mechanisms The oscillator 62 corresponding to 22 is disposed below the sheet conveyance path. For this reason, at least the first sound absorbing material 66 is provided in the sheet feeding mechanism 22 located near the oscillator 62, that is, the ultrasonic sensor 54 of the sheet feeding mechanism 22 adjacent to the lower side. Therefore, when the ultrasonic sensors 54 are provided in all of the plurality of sheet feeding mechanisms 22 arranged vertically, the first sound absorbing material 66 is provided in the sheet feeding mechanism 22 excluding the uppermost sheet feeding mechanism 22. Become.

  Further, the first sound absorbing material unit 56 is disposed so as to surround the vibration receiving device 64 together with the feed roller 60 disposed further downstream of the double feed detection mechanism 50. With reference to FIG. 3, the relationship with the delivery roller 60 will be described.

  FIG. 3 is a view of the sheet feeding mechanism 22 viewed from the viewpoint P of FIG. The paper feed mechanism 22 has a pair of shafts 70 to which a pair of feed rollers 60 are attached. The pair of delivery rollers 60 is provided on the downstream side of the paper conveyance mechanism 22 and conveys the paper delivered from the paper supply mechanism 22 further downstream of the paper conveyance mechanism. The first sound absorbing material 66 is disposed between the pair of delivery rollers 60 and surrounds the vibration receiving device 64 together with the pair of delivery rollers 60. Thereby, the ultrasonic wave which goes around from the side of the 1st sound-absorbing material unit 56, and advances to the direction of the geophone 64 can be suppressed. For this reason, the interference by the ultrasonic wave from the outside to the geophone 64 can be suppressed, and accurate double feed detection can be realized.

  Furthermore, it is preferable that the distance between the lower end of the first sound absorbing material 66 and the upper surface of the paper transport plate 46 be as narrow as possible. By doing so, in addition to the feeding roller 60, the vibration receiving device 64 including the paper conveying plate 46 is enclosed, and interference from ultrasonic waves from the outside can be more effectively suppressed.

  FIG. 4 is a diagram illustrating a detection signal of the ultrasonic sensor 54 when the first sound absorbing material unit 56 is removed. In the example illustrated in FIG. 4, a detection signal of the ultrasonic sensor 54 when double feeding is occurring is illustrated. The horizontal line at the center of the graph is a threshold value, and when this received value is equal to or less than the threshold value, it is determined to be double feeding. The second sound absorbing material 58 is attached at the time of measurement. As described above, when the first sound absorbing material unit 56 is deleted, it can be seen that the detection signal of the ultrasonic sensor 54 frequently exceeds the threshold value. For this reason, there is a possibility that erroneous detection occurs in this example.

  FIG. 5 is a diagram illustrating a detection signal of the ultrasonic sensor 54 when the first sound absorbing material unit 56 is attached. The example shown in FIG. 5 also shows a detection signal of the ultrasonic sensor 54 when double feeding occurs. The horizontal line at the center of the graph is a threshold value, and when this received value is equal to or less than the threshold value, it is determined to be double feeding. The second sound absorbing material 58 is attached at the time of measurement. It can be seen that external noise can be significantly reduced by attaching the first sound absorbing material unit 56 in this manner. For this reason, by attaching the first sound absorbing material unit 56, it is possible to greatly suppress the occurrence frequency of erroneous determination of double feeding.

  FIG. 6 shows the first level when the ultrasonic wave is oscillated from the oscillator 62 of the ultrasonic sensor 54 only in the uppermost (first) paper feed shelf 20 and the lower (second) paper feed shelf 20. It is a figure which shows the detection result of the geophone 64 of the ultrasonic sensor 54. FIG. Thus, even if an ultrasonic wave is oscillated from the ultrasonic sensor 54 of the lower paper feed shelf 20, the reception value of the ultrasonic sensor 54 of the upper paper feed shelf 20 has little influence.

  FIG. 7 shows the geophone 64 of the second-stage ultrasonic sensor 54 when ultrasonic waves are oscillated from the oscillator 62 of the ultrasonic sensor 54 only in the first-stage sheet feed shelf 20 and the second-stage sheet feed shelf 20. It is a figure which shows the detection result. As described above, when an ultrasonic wave is oscillated from the ultrasonic sensor 54 of the upper paper feed shelf 20, the received value of the ultrasonic sensor 54 of the lower paper feed shelf 20 is greatly affected. For this reason, when the paper feed shelf 20 provided with the ultrasonic sensor 54 exists in the upper stage, it turns out that the effect by attaching the 1st sound-absorbing material unit 56 is very large.

  FIG. 8 is a diagram illustrating a detection result of the geophone 64 of the ultrasonic sensor 54 when the first sound absorbing material 66 according to the present embodiment is used. FIG. 9 shows a geophone of the ultrasonic sensor 54 when a sound absorbing material having a width substantially the same as the width of the ultrasonic sensor 54 (hereinafter referred to as “short sound absorbing material”) is used in place of the first sound absorbing material 66. It is a figure which shows 64 detection results. Both show the detection results when double feeding occurs. Although the short sound-absorbing material is disposed between the pair of delivery rollers 60, a large gap is formed between the pair of delivery rollers 60, so that the geophone 64 cannot be enclosed together with the pair of delivery rollers 60.

  As can be seen from FIGS. 8 and 9, the value of the reception value by double feeding is lower when the first sound absorbing material 66 is used than when the short sound absorbing material is used. In the case of FIG. 9 as well, the received value is kept below the threshold value. For example, in order to detect double feeding of paper that is difficult to transmit ultrasonic waves, the threshold value may be set low. As shown in FIG. 9, the possibility of erroneous detection increases with a waveform showing a higher value. For this reason, by arranging the first sound absorbing material 66 so as to surround the vibration receiving device 64 together with the pair of delivery rollers 60, the vibration receiving value at the time of double feeding can be suppressed to be low, and erroneous detection can be suppressed.

  The present invention is not limited to the above-described embodiments, and an appropriate combination of the elements of each embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can also be included in the scope of the present invention.

  In a modification, the geophone 64 is disposed below the paper transport path, and the oscillator 62 is disposed above the paper transport path. Also in this case, the first sound absorbing material 66 detects the double feed of the paper feed mechanism 22 in which the oscillator 62 corresponding to the adjacent paper feed mechanism 22 is located closer to the paper feed path in the adjacent paper feed mechanism 22. It is provided corresponding to at least the acoustic wave sensor 54.

  Specifically, when a plurality of paper feed mechanisms 22 in which the oscillator 62 is disposed above the paper transport path and the geophone 64 is disposed below the paper transport path are arranged side by side, one of the paper feed mechanisms The oscillator 62 corresponding to 22 is disposed above the sheet conveyance path. For this reason, at least the first sound absorbing material 66 is provided in the sheet feeding mechanism 22 located near the oscillator 62, that is, the ultrasonic sensor 54 of the sheet feeding mechanism 22 adjacent to the upper side. Therefore, when the ultrasonic sensors 54 are provided in all of the plurality of sheet feeding mechanisms 22 arranged vertically, the first sound absorbing material 66 is provided in the sheet feeding mechanism 22 except the lowest sheet feeding mechanism 22. Become.

  DESCRIPTION OF SYMBOLS 10 Paper feeder, 12 Main body, 14 Multi-stage paper feed mechanism, 16 Horizontal conveyance mechanism, 20 Paper feed shelf, 22 Paper feed mechanism, 24 Belt conveyance mechanism, 30 Belt, 32 Tension roller, 34 Conveyance roller, 36 Paper guide, 38 Common transport path, 40 Paper separation mechanism, 41 Paper feed roller, 42 Pickup roller, 44 Separation member, 50 Double feed detection mechanism, 51 First plate, 52 Second plate, 54 Ultrasonic sensor, 56 First sound absorbing material unit, 58 second sound absorbing material, 60 delivery roller, 62 oscillator, 64 geophone, 66 first sound absorbing material, 68 elastic film.

Claims (6)

A plurality of paper feed mechanisms that are provided corresponding to the plurality of paper feed shelves, respectively, and that respectively feed paper from the corresponding paper feed shelves to the paper transport path;
Each of the plurality of paper feeding mechanisms includes an oscillator that oscillates an ultrasonic wave, and a vibration receiver that is disposed across the oscillator and the paper conveyance path, and the paper passes through the paper conveyance path. A plurality of ultrasonic sensors for detecting double feed when the paper is fed from the corresponding paper feed mechanism based on the waveform of the ultrasonic wave sometimes received by the geophone,
A plate-like sound absorbing material provided corresponding to any of the plurality of ultrasonic sensors, and disposed in the vicinity of the paper transport downstream side of the geophone of the corresponding ultrasonic sensor;
With
Sheet feeding apparatus sheet conveying direction upstream side of the periphery of the receiving shakers is it characterized in that communicates with the outside space. A plurality of paper feed mechanisms provided respectively corresponding to a plurality of paper feed shelves, each for feeding paper from the corresponding paper feed shelves onto a paper transport plate;
Each of the plurality of paper feeding mechanisms includes an oscillator that oscillates an ultrasonic wave, and a vibration receiver that is disposed across the oscillator and the paper conveyance path, and the paper passes through the paper conveyance path. A plurality of ultrasonic sensors for detecting double feed when the paper is fed from the corresponding paper feed mechanism based on the waveform of the ultrasonic wave sometimes received by the geophone,
A plate-like sound absorbing material provided corresponding to any of the plurality of ultrasonic sensors, and disposed in the vicinity of the paper transport downstream side of the geophone of the corresponding ultrasonic sensor;
A paper feeding device comprising: a space through which a paper passes, with the paper conveying plate as a lower end and at least a part of the sound absorbing material as an upper end. A plurality of paper feed mechanisms that are provided corresponding to the plurality of paper feed shelves, respectively, and that respectively feed paper from the corresponding paper feed shelves to the paper transport path;
Each of the plurality of paper feeding mechanisms includes an oscillator that oscillates an ultrasonic wave, and a vibration receiver that is disposed across the oscillator and the paper conveyance path, and the paper passes through the paper conveyance path. A plurality of ultrasonic sensors for detecting double feed when the paper is fed from the corresponding paper feed mechanism based on the waveform of the ultrasonic wave sometimes received by the geophone,
A plate-shaped sound absorbing material provided corresponding to any of the plurality of ultrasonic sensors, and disposed in the vicinity of the sheet conveying downstream side of the geophone of the corresponding ultrasonic sensor,
Provided on both sides in the direction orthogonal to the sheet conveying direction of the sound absorbing material on the sheet conveying downstream side of the sheet feeding mechanism, and further sends out the sheet fed from the sheet feeding mechanism to the sheet conveying downstream side, and A surrounding member arranged to surround the geophone together with a material;
A sheet feeding device comprising: A plurality of paper feed mechanisms that are provided corresponding to the plurality of paper feed shelves, respectively, and that respectively feed paper from the corresponding paper feed shelves to the paper transport path;
Each of the plurality of paper feeding mechanisms includes an oscillator that oscillates an ultrasonic wave, and a vibration receiver that is disposed across the oscillator and the paper conveyance path, and the paper passes through the paper conveyance path. A plurality of ultrasonic sensors for detecting double feed when the paper is fed from the corresponding paper feed mechanism based on the waveform of the ultrasonic wave sometimes received by the geophone,
A plate-like sound absorbing material provided corresponding to any of the plurality of ultrasonic sensors, and disposed in the vicinity of the paper transport downstream side of the geophone of the corresponding ultrasonic sensor;
A pair of rollers that are provided on the downstream side of the paper feed of the paper feed mechanism and that further feeds the paper fed from the paper feed mechanism to the downstream side of the paper feed;
With
The sound-absorbing material is disposed between the pair of rollers, and surrounds the vibration receiver together with the pair of rollers. Sheet feeding apparatus according to any one of claims 1 to 4, characterized in that it comprises further an elastic film disposed so as to overlap with the sound absorbing material The sound absorbing material is provided at least in correspondence with an ultrasonic sensor that detects a double feed of a paper feed mechanism in which an oscillator corresponding to the adjacent paper feed mechanism is located closer to the paper feed path in the adjacent paper feed mechanism. sheet feeding apparatus according to any one of claims 1 to 5, characterized in that.

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