JP2020070124A - Sheet carrier - Google Patents

Abstract

To provide a duplication-of-feed detector that in the case a plurality of ultrasonic sensors are arranged, there is no possibility to cause an erroneous detection due to an interference with an ultrasonic sensor adjacent to the ultrasonic receiving unit in a pair.SOLUTION: A sheet carrier in the present invention comprises transport means that carries a sheet P along a transport path 11 and first and second ultrasonic detection means that detect a sheet in the transport path. The respective ones of the first and second ultrasonic detection means are juxtaposed mutually orthogonally to a sheet-transport direction, and arranged in directions that no interference takes places mutually between an ultrasonic wave going from a first ultrasonic transmitting unit 20a the first ultrasonic detection means has to a first ultrasonic receiving unit 30a through the transport path and an ultrasonic wave going from a second ultrasonic transmitting unit the second ultrasonic transmitting unit 20b has to a second ultrasonic receiving unit 30b through the transport path.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheet detection device that detects the presence or absence of a conveyed sheet and whether or not a double feed has occurred in a sheet, a double feed determination device that uses the sheet detection device, and an image reading device.

  Scanners, printers, copiers, printers, ATMs (Automated Teller Machines), etc. are provided with a mechanism for separating and conveying sheet-like members one by one. However, there is a possibility that two or more sheet-shaped members may be conveyed while only one sheet-shaped member is conveyed, with some or all of them overlapping. For this reason, an apparatus that conveys sheet-shaped members needs a function of detecting double feeding of the sheet-shaped members. As a mechanism for detecting the double feeding of the sheet-shaped member, a double feeding detecting device using ultrasonic waves is widely used.

  Here, in such a double feed detection device, when ultrasonic waves are radiated vertically to the sheet-shaped member, a part of the ultrasonic waves is reflected from the sheet surface, and the reflected wave is transmitted to the sheet surface and the ultrasonic wave. It is known to diffusely reflect between vessels. The diffusely reflected signal may be received by the ultrasonic receiver as a noise component, which is one of the causes of degrading the sensor performance. Therefore, a configuration is adopted in which ultrasonic waves are obliquely applied to the sheet surface.

WO13 / 001762

  When a plurality of ultrasonic sensors are arranged side by side, there is a possibility that the ultrasonic sensors adjacent to each other interfere with the adjacent ultrasonic sensors to cause erroneous detection.

  Further, by arranging the ultrasonic sensors obliquely with respect to the paper surface, it is possible to prevent the ultrasonic waves diffusely reflected from the paper surface from interfering with other ultrasonic sensors. However, the above measures alone cannot completely prevent the interference with the adjacent ultrasonic sensors, and the interference is prevented by controlling the transmission of each ultrasonic sensor and shifting the timing. Therefore, there is a problem that complicated control is required and the process becomes complicated.

In order to solve the above problems, the sheet conveying device of the present invention,
Transporting means for transporting the sheet along the transport path,
First and second ultrasonic wave detecting means for detecting a sheet in the conveyance path,
Each of the first and second ultrasonic wave detecting means is provided side by side in a direction orthogonal to the sheet conveying direction, and the first ultrasonic wave transmitting portion of the first ultrasonic wave detecting means sandwiches the conveying path. 1 in a direction in which the ultrasonic wave toward the ultrasonic wave receiving section and the ultrasonic wave toward the second ultrasonic wave receiving section across the carrier path from the second ultrasonic wave transmitting section of the second ultrasonic wave transmitting section do not interfere with each other Characterized by arranging,
Sheet transport device.

  By using the solving means, it is possible to improve the accuracy of double feed detection while suppressing erroneous detection due to interference with the ultrasonic sensor adjacent to the paired ultrasonic wave receiving unit. It is possible to suppress erroneous detection due to interference between adjacent ultrasonic sensors without using complicated control. Further, it is possible to perform double feed detection corresponding to various types of sheet materials.

The schematic structure figure which looked at the principal part of the double feed detection device concerning Embodiments 1 to 4 of the present invention from the side. 1 is a schematic diagram showing a configuration of a main part of a double-feed detection device according to Embodiments 1 to 4 of the present invention. FIG. 6 is a schematic diagram showing a configuration of signal processing of the double-feed detection device according to the first to fourth embodiments of the present invention. 1 is a schematic configuration diagram showing a sheet processing apparatus according to Embodiments 1 to 4 of the present invention. Internal structure of the sheet-shaped member conveying device main body 801 according to Embodiments 1 to 4 of the present invention The schematic structure figure which looked at the double feed detection apparatus concerning Embodiments 1 to 4 of the present invention from the side. FIG. 6 is a diagram illustrating a jam that occurs when a document that is stapled is fed. The figure which showed the flowchart of the double feed detection which concerns on Embodiment 4 of this invention. The figure which showed the flowchart of the transmission of the double feed detection apparatus which concerns on Embodiments 2-4 of this invention. The figure which showed the transmission / reception timing of the ultrasonic pulse in the double feed detection apparatus which concerns on Embodiments 2-4 of this invention. The figure which showed the interference with the adjacent sensor in the conventional double feed detection apparatus.

(Example 1)
FIG. 1 is a diagram showing a schematic configuration of a double feed detection device according to a first embodiment of the present invention. In addition, FIG. 2 is a schematic schematic diagram showing a configuration of a main part of the double-feed detection device according to the first embodiment of the present invention.

  As shown in FIGS. 1 and 2, the multi-feed detection device 10 of the present embodiment is arranged in a conveyance path along which a sheet-shaped member (hereinafter, simply referred to as a sheet material) is conveyed, and a plurality of sheet materials are overlapped. It is a device that detects the double feed conveyed by the ultrasonic method.

Specifically, as shown in FIG. 1, a transport path 11 is provided in the sheet transport path for planarly transporting the sheet material P in the horizontal direction. The transport path 11 includes both upper guide guide plates (transport path forming members) 12 on the upper surface side and lower transport guide plates (transport path forming members) 13 on the lower surface that face each other across a planar transport space 11a. It is covered by the space between the plates 12 and 13. In the double-feed detection device 10 having such a configuration, the ultrasonic wave transmission unit 20 is disposed as an ultrasonic wave transmission (transmission) means above and opposite to each other with the conveyance path 11 interposed therebetween, and the ultrasonic wave reception means is disposed below as an ultrasonic wave reception means. The part 30 is provided.
Here, when the double feed of the sheet material is detected by using the ultrasonic sensor including the ultrasonic wave transmitting unit 20 and the ultrasonic wave receiving unit 30, the following detection performance peculiar to the ultrasonic wave is obtained.
(1) Since the detection is performed in a non-contact state where the sheet material does not come into contact with the sheet material, the conveyance of the sheet material is not disturbed.
(2) Since it can be detected regardless of the thickness of the sheet material, it is possible to detect even a double feed in which sheet materials having different thicknesses are mixed.
(3) Since the structure can be detected without being affected by the color of the sheet material, no adjustment is required even if the color of the sheet material changes.

  Therefore, the use of the ultrasonic sensor makes it possible to detect the double feeding of the sheet material with high sensitivity. On the other hand, when the sheet material is irradiated with ultrasonic waves, a part of the ultrasonic waves may be reflected from the sheet surface, and the reflected wave may be diffusely reflected between the sheet surface and the transmitter. Therefore, depending on the arrangement of the ultrasonic wave transmitter and the receiver, the reflected wave that is diffusely reflected may be received by the receiver as a noise component, and the noise component due to the diffused reflection may be one of the factors that deteriorate the sensor performance. .. Therefore, the traveling direction of the ultrasonic wave is inclined (angled) with respect to the sheet material (conveyance path), and the reflected wave is reflected in a direction different from that of the transmitter.

  Further, when a plurality of ultrasonic sensors are arranged, there is a risk that interference may occur in the ultrasonic sensor receiving section adjacent to the ultrasonic sensor forming a pair, resulting in double feed and erroneous detection.

  FIG. 11 shows interference with an adjacent sensor in the conventional double feed detection device. The ultrasonic wave traveling from the second ultrasonic wave transmitting unit 20b to the second ultrasonic wave receiving unit 30b across the conveyance path is reflected by both the conveyance guide plates 12 and 13 to become a reflected wave 14. When the first ultrasonic wave reception unit 30a receives the reflected wave 14, the first ultrasonic wave reception unit 30a may interfere with each other to cause erroneous detection.

  Therefore, the first and second ultrasonic wave detecting means and the first and second ultrasonic wave detecting means for detecting the sheet in the conveying path are provided side by side in the directions orthogonal to the sheet conveying direction.

  An ultrasonic wave (not shown) directed from the first ultrasonic wave transmitting unit 20a included in the first ultrasonic wave detecting unit to the first ultrasonic wave receiving unit 30a across the transport path, and a second ultrasonic wave included in the second ultrasonic wave transmitting unit. The ultrasonic waves (not shown) traveling from the transmitting unit 20b to the second ultrasonic receiving unit 30b across the transport path are opposite to each other.

  The first ultrasonic wave detecting means and the second ultrasonic wave detecting means may be arranged so as to face in a direction different by 90 degrees from the conveying direction.

  The angle of inclination to the end of the transport path is not 90 degrees perpendicular to the transport direction, but may be changed according to the directivity of the ultrasonic wave transmission unit.

  Hereinafter, the control configuration of the above-described double-feed detection device 10 will be described in detail with reference to FIG. FIG. 3 is a block diagram of a control circuit incorporated in the double feed detection device. The double-feed detection device 10 according to the present embodiment includes an oscillation circuit 22 as a signal generation unit that generates a signal of a predetermined frequency (for example, 300 kHz) on the ultrasonic wave transmission side, and a signal amplification unit that amplifies the signal from the oscillation circuit 22. And an amplifier circuit 23 as Further, on the ultrasonic wave reception side, a filter for removing noise and an amplification circuit 32 for amplifying the received signal, and a judgment circuit 33 as a double feeding judgment means for judging by comparing the received signal with a reference value. Are arranged.

  Then, the electric signal of the predetermined frequency output from the oscillation circuit 22 described above is amplified to a predetermined value by the amplification circuit 23, and then input to the ultrasonic wave transmission unit 20 to generate the ultrasonic wave generation element in the ultrasonic wave transmission unit 20. Are converted into ultrasonic waves U by. The converted ultrasonic waves U are radiated toward the receiver 30 via the sheet material P conveyed to the conveyance path 11.

  Further, the ultrasonic wave U emitted from the ultrasonic wave transmitting unit 20 hits the sheet material P conveyed in the conveying path 11, and a part thereof is radiated to the outside as a reflected wave R. The ultrasonic wave U ′ that has passed through the sheet material P is received by the ultrasonic wave receiving unit 30 and converted into an electric signal by the piezoelectric element or the MEMS element of the ultrasonic wave receiving unit 30. The signal converted into an electric signal is processed by a filter circuit and an amplifier circuit 32 having a filter function for removing noise and an amplifying function. Then, the determination circuit 33 determines whether one sheet material P has been conveyed or a plurality of sheet materials P has been conveyed by comparing with a threshold value, and based on the result, the presence or absence of double feeding of the sheet material P is determined. Detect. This determination signal is sent to the sheet material conveyance control system (control unit such as CPU) 34.

  Since the first ultrasonic wave detecting means and the second ultrasonic wave detecting means are arranged so as to face in a direction different by 90 degrees from the transport direction, the influence of noise components on the receiving unit can be minimized. ..

  As a result, the first ultrasonic wave detecting means and the second ultrasonic wave detecting means can accurately perform the double feed determination without interfering with each other.

  FIG. 4 is a diagram showing an example of the configuration of a sheet-shaped member conveying device provided with the double feed detecting device of the present invention.

  In FIG. 4, reference numeral 801 denotes a main body of an image reading apparatus (hereinafter, referred to as a sheet-like member conveying apparatus main body) as a sheet-like member conveying apparatus including the double feed detecting device 10. Reference numeral 802 is a feed port, 803 is a paper feed tray, 804 is an operation unit, 805 is a paper ejection port, and 806 is a paper ejection tray.

  When a scan instruction information is input from the operation unit 804, one sheet-shaped member (not shown) stacked on the sheet feeding tray 803 is inserted into the sheet-shaped member conveying apparatus main body 801 from the sheet feeding port 802. They are transported one by one. The image information of the sheet-shaped member conveyed inside the sheet-shaped member conveyance device main body 801 is read by an image reading sensor (not shown). After that, the sheet-shaped member is conveyed in the discharge direction, and is discharged from the sheet discharge port 805 to the outside of the sheet-shaped member conveying device main body 801. Then, the sheet-shaped members discharged to the outside of the sheet-shaped member conveying device main body 801 are sequentially stacked on the sheet discharge tray 806.

  FIG. 5 is a cross-sectional view showing the internal structure of the sheet-shaped member conveying device body 801 shown in FIG. 4, in which the same parts as those in FIG. 4 are designated by the same reference numerals.

  In FIG. 5, 901 is a feed roller, 902 is a retard roller, and a torque limiter 903 is provided between the rotation roller and the rotary shaft. By the action of the feed roller 901 and the retard roller 902, the sheet-shaped members 201 stacked on the sheet feeding tray 803 are separated one by one, and the sheet-shaped member conveying device main body 801 is fed from the sheet feeding port 802 into the sheet-shaped member conveying device main body 801 by an arrow in the figure. It is conveyed in the B direction. A conveying roller 904 is for further conveying the sheet-shaped members, which are conveyed one by one by the action of the feed roller 901 and the retard roller 902, toward the sheet discharge port 805.

  An image reading unit (back surface image reading unit) 905 reads the back surface of the sheet-shaped member. An image reading unit (front surface image reading unit) 906 reads the surface of the sheet-shaped member. This constitutes both image reading units. Inside the back image reading unit 905 and the front image reading unit 906, a light source (not shown) for irradiating the sheet-shaped member and an image reading sensor (not shown) for reading image information of the sheet-shaped member are incorporated.

  Further, both image reading units read the image of the sheet-shaped member. Reference numeral 907 denotes a first platen roller, which presses the conveyed sheet-shaped member so as to be in close contact with the back side image reading unit 905 at the reading position A.

  A second platen roller 908 presses the conveyed sheet-like member so as to come into close contact with it at the reading position A of the front surface image reading unit 906.

  A sheet discharge roller 909 discharges the conveyed sheet-shaped member from the sheet discharge port 805 to the outside of the sheet-shaped member conveying apparatus main body 801. Reference numeral 910 is a conveyance drive source, which is generally a conveyance motor. The transport drive source 910 is connected to the rotation shafts of the rollers by a gear mechanism or a belt mechanism (not shown). As a result, when the transport drive source 910 rotates, the rollers rotate, so that the sheet-shaped member is transported in a predetermined direction at a predetermined speed. When the transport driving source 910 rotates in the clockwise direction in FIG. 5, the sheet-shaped member is transported from the sheet feeding port 802 to the sheet discharging port 805. A document detection sensor 911 detects whether or not there is a sheet-like member in the paper feed port 802. Reference numeral 912 denotes a pre-paper feed detection sensor that detects the end of the sheet-shaped member that has been conveyed.

  An ultrasonic wave transmitting unit 103 and an ultrasonic wave receiving unit 104 for detecting the double feeding state of the sheet-shaped members to be fed are arranged on the upstream side of the conveying roller 904. The ultrasonic wave transmitting unit 103 and the ultrasonic wave receiving unit 104 are arranged so that the ultrasonic wave transmitted by the ultrasonic wave transmitting unit 103 can be received by the ultrasonic wave receiving unit 104 through the sheet-shaped member that is the target of double-feed detection. The strip-shaped members are installed so as to face each other across the transport path. The ultrasonic wave transmitting unit 103 and the ultrasonic wave receiving unit 104 may be provided downstream of the transport roller 904.

  As shown in FIG. 6, the ultrasonic wave transmitting unit 20 and the ultrasonic wave receiving unit 30 may have a configuration of three pairs or more. Ultrasonic waves traveling from the first ultrasonic wave transmission unit 20a included in the first ultrasonic wave detection unit to the first ultrasonic wave reception unit 30a across the transport path, and the second ultrasonic wave transmission unit 20b included in the second ultrasonic wave transmission unit. The ultrasonic waves traveling from the sheet to the second ultrasonic wave receiving unit 30b with the conveyance path sandwiched therebetween are arranged in a direction orthogonal to and opposite to the sheet conveyance direction, and the third ultrasonic wave included in the third ultrasonic wave transmission means. The ultrasonic waves traveling from the transmitting unit 20c to the third ultrasonic wave receiving unit 30c across the conveyance path may be inclined along the sheet conveyance direction.

  In addition, an ultrasonic wave from the first ultrasonic wave transmission unit 20a included in the first ultrasonic wave detection unit to the first ultrasonic wave reception unit 30a across the transport path, and a second ultrasonic wave transmission included in the second ultrasonic wave transmission unit. An ultrasonic wave traveling from the portion 20b to the second ultrasonic wave receiving unit 30b across the transport path, and a third ultrasonic wave receiving unit sandwiching the transport path from the third ultrasonic wave transmitting unit 20c included in the third ultrasonic wave transmitting means. A configuration may be adopted in which at least one of the ultrasonic waves traveling toward 30c is inclined toward the end portion side of the conveyance path in the direction orthogonal to the sheet conveyance direction.

(Example 2)
Next, a double feed detection device according to a second embodiment of the present invention to which the above means is applied will be described. The schematic configuration of the double feed detection device according to the second embodiment is similar to that of the first embodiment. (See Figure 1)

  The structure of the main part of the double feed detection apparatus according to the second embodiment is similar to that of the first embodiment. (See Figure 2)

  The control configuration of the double feed detection device according to the second embodiment is the same as that of the first embodiment. (See Figure 3)

  FIG. 9 is a diagram showing a control flow of ultrasonic wave transmission in the double feed detection apparatus according to the second embodiment.

  The sheet material transportation control system (CPU) 34 transmits a control command to the transportation driving source 910. When the conveyance driving source 910 is driven, the feed roller 901 is rotated, and the sheet material P is separated by the retard roller 902 that rotates in the opposite direction, thereby feeding the sheet. The conveyance roller 904 is rotated to convey the sheet material P. (S901)

  The CPU 34 sends a command to the ultrasonic wave transmitting unit 20. The first ultrasonic wave transmitter 20a transmits for t1 [s] and the second ultrasonic wave transmitter 20b transmits for t2 [s] (S902), and then stops. (S903) The CPU 34 determines whether or not the conveyance is completed (S904), and when the conveyance is continued, the first ultrasonic wave transmission unit 20a and the second ultrasonic wave transmission unit 20b each time tw [s] elapses. Call again.

  When the conveyance is completed, the series of operations for double feed detection is completed.

  In the present embodiment, the first ultrasonic wave detecting means and the second ultrasonic wave detecting means are arranged so as to face in a direction different by 90 degrees from the conveying direction, so that the ultrasonic wave receiving unit 30 is not affected by reverberation noise. Can be minimized.

  Therefore, as shown in FIG. 10, it is possible to simultaneously transmit the first ultrasonic wave detecting means and the second ultrasonic wave detecting means.

(Example 3)
Next, a multi-feed detection device according to a fourth embodiment of the present invention to which the above means is applied will be described.
The schematic configuration of the double feed detection device according to the third embodiment is similar to that of the first and second embodiments. (See Figure 1)

  The structure of the main part of the double feed detection apparatus according to the third embodiment is similar to that of the first and second embodiments. (See Figure 2)

  The control configuration of the double feed detection device according to the third embodiment is similar to that of the first and second embodiments. (See Figure 3)

  The ultrasonic pulse oscillated from the ultrasonic transmitter 20 is received by the ultrasonic receiver 30.

  The ultrasonic pulse received by the ultrasonic wave receiving unit 30 is attenuated by passing through the sheet material P, but the attenuation rate differs depending on the “type of sheet material P”.

  The ultrasonic pulse received by the ultrasonic receiving unit 30 is input to the filter circuit amplifier 32, and the “band centered on the frequency of the transmitted ultrasonic pulse” is extracted.

  The band-extracted ultrasonic pulse (ultrasonic signal amplitude) is amplified by the filter circuit amplifier 32 to a “level at which it is easy to determine double feed detection” and transmitted to the determination circuit 33.

  Then, the determination circuit 33 makes a comparison determination with the double feed thresholds Vth1 and Vth2 to determine whether or not the double feed is performed.

  The determination result of the comparison determination is transmitted to the CPU 34.

  Vth1 and Vth2 described here indicate the respective double feed determination thresholds in the first ultrasonic wave detecting means and the second ultrasonic wave detecting means. By using a plurality of threshold values provided individually, it becomes possible to relax the restriction on the sheet material P and widen the range in which double feed can be detected.

  In the present embodiment, the first ultrasonic wave detecting means and the second ultrasonic wave detecting means are arranged so as to face in a direction different by 90 degrees from the conveying direction, so that the ultrasonic wave receiving unit 30 is not affected by reverberation noise. Can be minimized.

  As a result, the first ultrasonic wave detecting means and the second ultrasonic wave detecting means can respectively judge in a wider range. Further, by setting a large difference between Vth1 and Vth2 for the comparison determination, it is possible to accurately perform the double feeding detection of the sheet materials P having different attenuation rates and having various thicknesses.

(Example 4)
Next, a double-feed detection device according to a fifth embodiment of the present invention to which the above means is applied will be described. The schematic configuration of the double-feed detection device according to the fourth embodiment is similar to that of the first to third embodiments. (See Figure 1)

  The structure of the main part of the double feed detection apparatus according to the fourth embodiment is similar to that of the first to third embodiments. (See Figure 2)

  The control configuration of the double feed detection device according to the fourth embodiment is similar to that of the first to third embodiments. (See Figure 3)

  FIG. 8 is a diagram showing a control flow of the double feed detection apparatus according to the fourth embodiment.

  The sheet material transportation control system (CPU) 34 transmits a control command to the transportation driving source 910. When the transport driving source 910 is driven, the feed roller 901 is rotated, and the sheet material P is separated by the retard roller 902 that rotates in the opposite direction, thereby feeding the sheet. (S801)

  The conveyance roller 904 is rotated to convey the sheet material P. (S802)

  The plurality of ultrasonic wave receiving units 104 detect whether or not the sheet material being conveyed is multi-fed (S803), and a command to stop the conveyance from the CPU 34 is detected when the multi-feed is detected or the sheet material P is exhausted. Continue transport until received. (S804)

Of the plurality of ultrasonic wave receiving units 104, when one of the ultrasonic double feed detecting units detects the double feed and when the other ultrasonic double feed detecting unit also detects the double feed, the separation roller is detected. Check if the load increases above a certain value. A pressure sensor for measuring the pressure of the separation roller or a DC motor for the conveyance drive unit may be used as the confirmation unit to measure the current value.
When the load is increased, it is determined that the sheet material P is jammed in the conveyance path, and the conveyance drive unit is stopped.

  If the load has not increased, it is determined that the sheet is a general double feed, and the sheet material P is stopped at the sheet discharge unit 805.

  The ultrasonic wave U emitted from the ultrasonic wave transmitting unit 20 hits the sheet material P conveyed in the conveying path 11, and a part thereof is radiated to the outside as a reflected wave R. The ultrasonic wave U ′ that has passed through the sheet material P is received by the ultrasonic wave receiving unit 30 and converted into an electric signal by the piezoelectric element or the MEMS element of the ultrasonic wave receiving unit 30. The signal converted into an electric signal is processed by a filter circuit and an amplifier circuit 32 having a filter function for removing noise and an amplifying function. Then, the determination circuit 33 determines whether one sheet material P has been conveyed or a plurality of sheet materials P has been conveyed (double feeding) by comparing with a threshold value, and based on the result, the weight of the sheet material P is determined. The presence or absence of sending is detected. The determination signal is sent to the CPU 34.

  When one ultrasonic wave double-feed detection is detected and the other ultrasonic wave double-feed detection is detected, it is determined that the sheet is a normal double-feed, and the sheet member is stopped at the paper discharge unit.

  A sectional view showing the internal structure of the sheet-shaped member conveying device main body 801 is also the same as in the first to third embodiments. (See Figure 5)

  By the action of the feed roller 901 and the retard roller 902, the sheet-shaped members 201 stacked on the sheet feeding tray 803 are separated one by one, and the sheet-shaped member conveying device main body 801 is fed from the sheet feeding port 802 into the sheet-shaped member conveying device main body 801 by an arrow in the figure. It is conveyed in the B direction.

  However, when the sheet bundle is bound by a metal fastening member such as staple, the sheet material P may be damaged because the sheet bundle cannot be separated by the feed roller 901 and the retard roller 902. (See Figure 7)

  Generally, metal fastening members such as staples are often used to bind the front end portion, the rear end portion, the left end portion, and the right end portion of the sheet bundle.

  In this embodiment, ultrasonic waves are transmitted to the end of the transport path. When the sheet bundle is bound by the metal fastening member, the gap between the sheet materials is smaller than that in the normal double feeding, so that the attenuation rate is also small. The staple SP1 is detected using this difference.

  By providing the ultrasonic wave detecting portions on the sheet regulating portions (not shown) on the left and right of the sheet feeding tray 803, the staple SP1 can be effectively detected.

10 Double-Feed Detection Device 11 Conveyance Path 11a Conveyance Space 12 Upper Conveyance Guide Plate 12a Inlet 13 Lower Conveyance Guide Plate 13a Outlet 14 Reflected Wave 20 Ultrasonic Wave Transmitting Unit 20a First Ultrasonic Wave Transmitting Unit 20b Second Ultrasonic Wave Transmitting Unit 20c Third ultrasonic wave transmitting section 21 Substrate having circuit board including fixing member and drive circuit 22 Oscillation circuit 23 Amplifying circuit 30 Ultrasonic wave receiving section 30a First ultrasonic wave receiving section 30b Second ultrasonic wave receiving section 30c Third ultrasonic wave Receiver 31 Substrate having a circuit board including a fixing member and an amplifier circuit 32 Filter circuit amplifier 33 Judgment circuit 34 Sheet conveyance control system (CPU)
103 Ultrasonic Transmitter 104 Ultrasonic Receiver A Reading Position P Sheet Material (Original)
P'sheet bundle R reflected wave U ultrasonic waves emitted from the transmitter U'ultrasonic waves SP1 staple passing through the sheet material

Claims (4)

Transporting means for transporting the sheet along the transport path,
First and second ultrasonic wave detecting means for detecting a sheet in the conveyance path,
Each of the first and second ultrasonic wave detecting means is provided side by side in a direction orthogonal to the sheet conveying direction, and the first ultrasonic wave transmitting portion of the first ultrasonic wave detecting means sandwiches the conveying path. 1 in a direction in which the ultrasonic wave toward the ultrasonic wave receiving section and the ultrasonic wave toward the second ultrasonic wave receiving section across the carrier path from the second ultrasonic wave transmitting section of the second ultrasonic wave transmitting section do not interfere with each other A sheet conveying device characterized by being arranged.   The sheet conveying apparatus according to claim 1, wherein the first ultrasonic wave transmission unit and the second ultrasonic wave transmission unit transmit at the same timing. The first ultrasonic wave detection means detects a double feed of sheets by comparing a signal transmitted from the first ultrasonic wave transmission unit and received by the first ultrasonic wave reception unit with a detection reference, and 2 The ultrasonic detecting means is a sheet conveying device which detects the double feeding of sheets by comparing the signal transmitted from the second ultrasonic transmitting portion and received by the second ultrasonic receiving portion with a detection reference,
3. The sheet conveying apparatus according to claim 1, wherein the first and second ultrasonic wave detecting units have different detection standards. The document conveyance by the conveyance unit is interrupted when at least one of the first and second ultrasonic wave detection units and the second ultrasonic wave detection unit determines a double feed. The sheet conveying device according to any one of 1 to 3.

Images