JP6952504B2 - Image reader - Google Patents

Description

The present invention relates to a sheet transfer device having a function of detecting sheet overlap (sheet double feed) using ultrasonic waves, and an image reading device provided with the sheet transfer device.

In a sheet transfer device applied to scanners, printers, copiers, printing machines, ATMs (Automated Teller Machines), etc., since a plurality of sheets are continuously conveyed, the sheets are separated one by one and sequentially transferred. Feed into the device. In recent years, the development of a sheet transfer device that improves the reliability of transfer by adding a double feed detection function using ultrasonic waves to the sheet feeder has been progressing.

In the technique of Patent Document 1, a sheet transfer device capable of performing double feed detection while the sheet being conveyed is temporarily stopped has been proposed. As a result, by detecting whether or not the double feed is performed on the stopped sheet, the overlap of the sheets can be accurately detected, and the detection accuracy of the double feed can be improved.

In the technique of Patent Document 2, a sheet transfer device that detects the presence or absence of a sheet by using ultrasonic double feed detection has been proposed. This makes it possible to suppress the transmission of excessive ultrasonic waves and reduce the number of oscillation pulses in the state where the presence or absence of a sheet is detected, that is, in the section called between papers, which indicates between one sheet and the next sheet. Become.

In the technique of Patent Document 3, an ultrasonic detection device that transmits a plurality of ultrasonic waves at different transmission intervals has been proposed. By this, the user can change the burst transmission cycle in the burst transmission method of ultrasonic waves. It is possible to make the sound waves in the audible range less audible.

Japanese Patent No. 4242884 Japanese Patent No. 4695546 Japanese Unexamined Patent Publication No. 2012-148873

Here, in the conventional double feed detection device, there is a problem that the noise transmitted to the outside of the device due to the transmission of ultrasonic waves cannot be sufficiently reduced.

The present invention is to provide a effective reading images Ru can be reduced device noise due to the detection ultrasonic multifeed.

The image reading device of the present invention is provided in a sheet transport path and is provided so as to face a sound wave transmitting section that transmits ultrasonic waves and the sound wave transmitting section across the transport path, and a signal corresponding to the received sound wave. A sound wave receiving unit that outputs a sound wave, an ultrasonic wave receiving signal generating unit that amplifies a signal having a frequency in the ultrasonic band from the signal output from the sound wave receiving unit to generate an ultrasonic wave receiving signal, and the sound wave receiving signal. A double feed determination unit that determines whether or not a plurality of sheets are overlapped and conveyed in the transfer path based on the above, a transfer control unit that controls the transfer and stop of the sheets, and an image reading unit that reads an image of the sheets. In a state where the sheet is passing between the sound wave transmitting unit and the sound wave receiving unit and the image memory unit in which the reading data of the image read by the image reading unit is taken in, the sheet is stopped in response to the stop of the transport of the sheet. The transport control unit includes a sound wave transmission control unit that controls the sound wave transmission unit to stop the transmission of sound waves, and the transport control unit is in a state where the sheet passes between the sound wave transmission unit and the sound wave reception unit. The image memory unit is characterized in that the transfer of the sheet is stopped when there is no free area for capturing the read data or when the read data is waiting to be transferred to the transfer destination.

According to the present invention, it is possible to realize the effective reading images Ru can be reduced device noise due to the detection ultrasonic multifeed. For example, when the transfer of the sheet is stopped regardless of the presence or absence of the sheet between the ultrasonic wave transmitting unit and the ultrasonic wave receiving unit, the ultrasonic wave transmission is stopped, so that the operator makes an unpleasant sound due to the ultrasonic wave. Can provide products that do not give.

A document reader equipped with a function to detect overlapping of sheets using ultrasonic waves. Block diagram of the double feed detection device. Cross-sectional view of the double feed detection device. The flowchart which shows the ultrasonic wave transmission control of a document reading apparatus. The block diagram of the modification of the double feed detection device. The flowchart which shows the ultrasonic wave transmission control of the modification of the document reading apparatus. A flowchart showing ultrasonic control of the document reader according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Example 1)
FIG. 1 is a cross-sectional view schematically showing a document reading device having a function of detecting overlapping of sheets by using ultrasonic waves as a sheet transporting device according to an embodiment of the present invention.

Here, the sheet transport device according to the present embodiment is a document transport device that transports a sheet-shaped document F, but instead of the document F, a recorded material (sheet) that does not form an image is used as an image forming device. It can also be used as a recording material transporting device for transporting to an image forming means. Further, the document transporting device may be provided not in the device main body of the document reading device but in the device main body of the document post-processing device for binding or forming holes in the document F.

In FIG. 1, the document reading device 100 feeds a document table 1 on which a document F, which is a sheet before transfer, is loaded, and a document F mounted on the document table 1 one by one. A pickup roller 2 as a rotating body and a retard roller 3 as a separated rotating body for preventing the intrusion of a plurality of sheets are provided.

The document F is separated and conveyed one by one by passing through the pick roller 2 and the retard roller 3. The retard roller 3 may be a separation pad instead of a roller-shaped separation rotating body.

After the document F is fed into the apparatus, the document F passes between the sound wave transmitting unit 4a and the sound wave receiving unit 4b for detecting the overlap of the documents using ultrasonic waves. That is, the sound wave transmitting unit 4a and the sound wave receiving unit 4b form an ultrasonic wave detecting unit (sensor).

Further, the document reading device 100 includes a transport roller pair 5a, 5b and a transport roller pair 7a, 7b. Further, the document reading device 100 includes image reading sensors 6a and 6b on the front surface side and the back surface side of the document F.

The image reading sensors 6a and 6b read the image information on the front surface side and the back surface side of the conveyed document F, respectively, and output an image signal. Based on this output image signal, image data is generated by an image processing unit (not shown). The scanning intervals of the image reading sensors 6a and 6b are set according to the reading speed and resolution of the document F.

The document F ejected from the document reading device 100 is loaded on the paper ejection loading unit 8.
In FIG. 2, reference numeral 101 denotes a double feed detection device for detecting overlapping of documents using ultrasonic waves. The double feed detection device 101 includes a control unit 102, a sound wave transmitting unit 4a, and a sound wave receiving unit 4b.

The control unit 102 includes a CPU 102A, a ROM 102B, and a RAM 102C. The CPU 102A reads the program from the ROM 102B and controls the double feed detection device 101 using the RAM 102C as a work area. Further, the CPU 102A controls the start or stop of the transmission of the sound wave transmission unit 4a via the ultrasonic wave transmission circuit (ultrasonic wave transmission control unit) 102D. Further, the CPU 102A performs a calculation using the calculation unit 102F based on the reception result of the ultrasonic wave reception circuit 102E, and determines whether or not the document is double-fed. Further, the CPU 102A controls the transport unit 105 via the transport drive circuit 102G.

The sound wave transmitting unit 4a and the sound wave receiving unit 4b will be described. The sound wave transmitting unit 4a is an ultrasonic transmitter, and transmits ultrasonic waves to a document (sheet-like member) in a transport path. The sound wave receiving unit 4b is an ultrasonic wave receiver, and receives the ultrasonic waves transmitted by the sound wave transmitting unit 4a. The ultrasonic wave reception result (ultrasonic wave reception signal) by the sound wave receiving unit 4b is output to the ultrasonic wave receiving circuit 102E, and the signal is processed by the ultrasonic wave receiving circuit 102E.

As shown in the cross-sectional view of the double feed detection device of FIG. 3, the sound wave receiving unit 4b sandwiches the sound wave transfer path 202 of the document so that the ultrasonic wave transmitted through the document to be detected by the double feed can be received. It is installed so as to face the transmitting unit 4a. That is, the sound wave transmitting unit 4a is installed on one side of the transport path of the document 201 and transmits ultrasonic waves in the direction of the document 201. Further, the sound wave receiving unit 4b is installed on the other side of the transport path of the document 201, receives the ultrasonic waves transmitted by the sound wave transmitting unit 4a, and outputs the ultrasonic wave receiving signal to the ultrasonic wave receiving circuit 102E.

The sound wave transmitting unit 4a receives a pulse signal of several tens of kHz to several hundreds of kHz (hereinafter referred to as an ultrasonic signal) from the ultrasonic transmitting circuit 102D, and outputs an ultrasonic pulse. The ultrasonic signal supplied by the ultrasonic wave transmitting circuit 102D to the sound wave transmitting unit 4a is, for example, a signal that transmits a pulse signal of several tens of kHz to several hundreds of kHz for several cycles over a certain period of time. This is a method generally called burst transmission, and ultrasonic pulses are burst-transmitted every several hundred μSec.

FIG. 3 shows a cross-sectional view of the double feed detection device. 201 indicates a manuscript, and 202 indicates a wall of a transport path. Here, when the conveyed document 201 enters between the sound wave transmitting section 4a and the sound wave receiving section 4b, the ultrasonic waves transmitted from the sound wave transmitting section 4a are attenuated by the document 201 until they reach the sound wave receiving section 4b. Since the signal is very weak, the amplitude of the ultrasonic wave reception signal output by the sound wave receiving unit 4b is also weak.

In order to receive a weak signal, the ultrasonic wave receiving circuit 102E includes a signal amplifier circuit 110 that amplifies the ultrasonic wave receiving signal output by the sound wave receiving unit 4b, and can determine the double feed detection of the ultrasonic wave receiving signal. Amplifies to the signal amplitude.

The ultrasonic reception circuit 102E has an AD converter 111, samples an ultrasonic reception signal (analog signal) amplified by the signal amplification circuit 110, converts it into a digital signal, and outputs it to the CPU 102A. When the CPU 102A has a built-in AD converter, the ultrasonic reception signal (analog signal) amplified by the signal amplification circuit 110 is directly input to the CPU 102A.

The CPU 102A acquires the ultrasonic wave reception signal output from the ultrasonic wave reception circuit 102E and stores it in the work area RAM 102C as the amplitude information of the ultrasonic wave reception signal. Then, the CPU 102A performs a calculation using the calculation unit 102F based on the amplitude information held in the work area RAM 102C, and determines whether or not the document 201 is double-fed.

The transport drive circuit 102G is a circuit for transporting a sheet, and indicates a motor drive circuit, various seat detection sensors in which a transport path is arranged, and the like. The CPU 102A directly controls the transport drive circuit 102G, but if the scale of the device is large, a transport control CPU that is a slave of the CPU 102A may be provided.

The transfer drive circuit 102G can drive a transfer unit 105 composed of a motor, rollers, and the like, and can transfer and stop the sheet at a speed according to preset conditions under the control of the CPU 102A.

The situation in which the sheet transfer is stopped means that the image reading processing capacity is insufficient due to the sheet transfer, the processing capacity of the device connected to the device is insufficient, or the sheet transfer stop command is given by the device operator. , Etc., regardless of the presence or absence of a sheet between the sound wave transmitting unit 4a and the sound wave receiving unit 4b.

The CPU 102A controls the ultrasonic wave transmitting unit 4a to transmit ultrasonic waves via the ultrasonic wave transmitting circuit 102D while the sheet is conveyed by issuing a conveying command to the conveying drive circuit 102G.

The CPU 102A issues an stop command to the transfer drive circuit 102G to stop the transfer of the sheet regardless of the presence or absence of the sheet between the sound wave transmitting unit 4a and the sound wave receiving unit 4b, while the ultrasonic wave is emitted from the sound wave transmitting unit 4a. Is controlled so as not to transmit. It should be noted that the ultrasonic wave transmission from the ultrasonic wave transmission unit 4a is restarted in accordance with the restart of the sheet transfer.

Alternatively, the CPU 102A may control the ultrasonic wave transmitting unit 4a to transmit ultrasonic waves so as not to be heard in the human audible range while the transfer drive circuit 102G is issued a stop command to stop the sheet transfer. good. For example, when ultrasonic waves are burst-transmitted at regular intervals rather than constantly, and the burst transmission time interval is 500 μsec, the frequency becomes 2 kHz, which is from 20 Hz, which is considered to be the human audible range. It can be heard because it enters 20 kHz, but if the time interval of burst transmission is lengthened to 100 ms while the sheet transfer is stopped, the frequency becomes 10 Hz and it becomes inaudible outside the audible range. Alternatively, the time interval for burst transmission may be shortened.

FIG. 4 is a flowchart showing ultrasonic control of the document reading device according to the embodiment of the present invention.

The flow of ultrasonic wave control starting from step S401 of ultrasonic wave transmission control will be described with reference to FIG.

When the device operator executes the sheet transfer start step S402, the CPU, which is the control unit of the device, determines in step S403 whether or not the sheet is being transferred.

If it is determined in step S403 that the sheet is being conveyed, the ultrasonic wave transmission process is executed in step S404, the ultrasonic wave reception process is executed in step S405, and the ultrasonic wave reception signal is also executed in step S406. Detects double feeding of sheets. After that, in step S407, it is determined whether or not the sheet transfer is completed. If the sheet transfer is not completed, the process returns to the determination of whether or not the sheet transfer is in progress in step S403.

If it is determined in step S403 that the sheet transfer is not in progress, the ultrasonic wave stop process is executed in step S408, and it is determined in step S407 whether or not the sheet transfer is completed. If the sheet transfer is not completed, the process returns to the determination of whether or not the sheet transfer is in progress in step S403.

The situation where the sheet is not being transported even though the sheet has started to be transported is, for example, during the warm-up of the product body, waiting for the device operator to install the sheet, or to the reading data of the sheet or the sheet. It is assumed that the print data is waiting to be transferred.

If it is determined in step S407 that the sheet transfer is completed, the ultrasonic wave stop process is executed in step S409, and the sheet transfer is completed in step S410.

FIG. 7 is a flowchart showing ultrasonic control of the document reading device according to the embodiment of the present invention.

The flowchart of FIG. 7 describes ultrasonic control starting from step S701 of ultrasonic wave transmission control, assuming a scanner which is an input device for reading an image of a sheet connected to a PC.

When the scan start S702 is instructed by the device operator and the sheet transfer drive start step S703 is executed, the CPU, which is the control unit of the device, determines the free area of the image memory inside the scanner in step S704. If there is a free area in the image memory, the scanned image can be captured. Therefore, the next step is performed, and S705 determines whether or not the data can be transferred to the PC.

When it is determined in step S705 that data transfer to the PC is possible, the ultrasonic wave transmission process is executed in step S706, the ultrasonic wave reception process is executed in step S707, and the ultrasonic wave is transmitted in step S708. Detects double feeding of sheets based on the received signal. After that, in step S709, it is determined whether or not the sheet transfer is completed. If the sheet transfer is not completed, the process returns to the determination of the free area of the image memory in step S704 while continuing the sheet transfer.

If it is determined in step S704 that there is no free area in the image memory, or if it is determined in step S705 that data transfer to the PC is not possible, the sheet transfer drive is stopped in step S710 and the sheet transfer drive is stopped in step S711. Performs ultrasonic stop processing. After that, in step S709, it is determined whether or not the sheet transfer is completed. If the sheet transfer is not completed, the process returns to step S704 again to determine the free area of the image memory.

For example, the state in which the free area of the image memory is exhausted is a case where the image processing applied to the read image takes a long time, or a case where the sheet conveying capacity exceeds the image processing capacity of the scanner.

For example, a state in which data cannot be transferred to a PC means that it takes time to process an image or save an image on the PC, the data transfer speed to the PC is slow, or the PC shifts to a standby state or a hibernation state. If you have done so, etc.

If it is determined in step S709 that the sheet transfer is completed, the scan end process is executed in step S712, and the process ends in step S713.

(Example 2)
FIG. 5 is a diagram showing a double feed detection device 501 which is a modified example of the double feed detection device 101 for detecting the overlap of sheets by using ultrasonic waves.

The double feed detection device 501 of FIG. 5 has basically the same configuration as the document reading device 100 described above, and the same components are designated by the same reference numerals and duplicated description is omitted. The elements will be described.

In FIG. 5, the double feed detection device 501 is characterized by including an audible sound receiving circuit 102H in addition to the ultrasonic wave receiving circuit 102E described above as a circuit for receiving a signal output from the sound wave receiving unit 4b.

Assuming that the frequency of the ultrasonic wave used is 300 kHz, the signal amplifier circuit 110 in the ultrasonic wave receiving circuit 102E has a function of selectively amplifying a frequency in the vicinity of 300 kHz. By using an operational amplifier, it is possible to amplify a signal aiming at a specific frequency. Alternatively, a filter circuit that allows a specific frequency band to pass may be used.

The signal amplification circuit 112 in the audible sound receiving circuit 102H has a function of selectively amplifying a frequency of 20 Hz to 20 kHz. By using an operational amplifier, it is possible to amplify a signal aiming at a specific frequency. Alternatively, a filter circuit that allows a specific frequency band to pass may be used.

The CPU 102A controls to transmit ultrasonic waves from the sound wave transmitting unit 4a when the sheet is being conveyed by monitoring the sound of the sheet being conveyed in the audible range. FIG. 5 introduces a configuration in which the CPU 102A directly controls the transport drive circuit 102G, but the present invention is not limited to this, and a configuration having another CPU for transport control is also conceivable. When there are a plurality of control CPUs as described above, the function that the CPU 102A can independently monitor the sheet transport sound and control the transmission and stop of ultrasonic waves as in the present embodiment works effectively.

Further, from the output of the audible sound receiving circuit 102H, it has a function of not only detecting the presence or absence of transport of the sheet by the presence or absence of the transport sound, but also the presence or absence of a paper jam such as a jam and the presence or absence of step-out of the motor. You may let me.

Further, from the output of the audible sound receiving circuit 102H, not only the presence / absence of transport of the sheet may be detected by the presence / absence of the transport sound, but also a function of identifying a command based on the voice emitted by the device operator may be provided.

FIG. 6 is a flowchart showing ultrasonic control of a modified example of the document reading device according to the embodiment of the present invention.

The flow of ultrasonic wave control starting from step S601 of ultrasonic wave transmission control will be described with reference to FIG.

When the device operator executes the sheet transfer start step S602, the CPU, which is the control unit of the device, receives the audible sound in step S603, and determines from the audible sound whether or not the sheet is being transferred from the audible sound in step S604. ..

When it is determined in step S604 that the sheet is being conveyed, the ultrasonic wave transmission process is executed in step S605, the ultrasonic wave reception process is executed in step S606, and the ultrasonic wave reception signal is also executed in step S607. Detects double feeding of sheets. After that, in step S608, it is determined whether or not the sheet transfer is completed. If the sheet transfer is not completed, the process returns to the reception of the audible sound in step S603.

If it is determined in step S604 that the sheet transfer is not in progress, the ultrasonic wave stop process is executed in step S609, and it is determined in step S608 whether or not the sheet transfer is completed. If the sheet transfer is not completed, the process returns to the reception of the audible sound in step S603.

When it is determined in step S608 that the sheet transfer is completed, the ultrasonic wave stop process is executed in step S610, and the process ends in step S611.

Further, an object of the present invention is to supply a storage medium for storing a program code of software that realizes the functions of the above-described embodiments to a system or device, and to supply a computer (or CPU, MPU, etc.) of the system or device. Is also achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention. ..

The storage medium for supplying the program code includes, for example, a floppy (registered trademark) disk, a hard disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, or a DVD. -Optical discs such as RW and DVD + RW, magnetic tapes, non-volatile memory cards, ROMs and the like can be used. Alternatively, the program code may be downloaded via the network.

Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) running on the computer is based on the instruction of the program code. Etc. may perform a part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted in the computer or the function expansion unit connected to the computer, the extension function is based on the instruction of the program code. This includes the case where the CPU provided in the expansion board or the expansion unit performs a part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

100 Document reader 1 Document stand F Document 2 Pickup roller 3 Return roller 4a Sound wave transmitter 4b Sound wave receiver 5a, 5b Conveyor rollers 7a, 7b Conveyor rollers 6a Front side image reading sensor 6b Back side image reading sensor 8 Paper discharge loading unit 101 Double feed detection device 102 Control unit 102A CPU
102B ROM
102C RAM
102D Ultrasonic transmission circuit 102E Ultrasonic reception circuit 110 Signal amplifier circuit 111 AD converter 102F Calculation unit 102G Transport drive circuit 105 Transport unit 201 Manuscript 202 Transport path 501 Double feed detection device 102H Hearing sound reception circuit 112 Signal amplification circuit 113 AD converter

Claims (1)

A sound wave transmitter that is installed in the sheet transport path and emits ultrasonic waves,
A sound wave receiving unit provided so as to face the sound wave transmitting unit across the transport path and outputting a signal corresponding to the received sound wave, and a sound wave receiving unit.
An ultrasonic reception signal generation unit that amplifies a signal having a frequency in the ultrasonic band from the signal output from the sound wave reception unit to generate an ultrasonic reception signal, and an ultrasonic reception signal generation unit.
A double feed determination unit that determines whether or not a plurality of sheets are overlapped and transported in the transport path based on the ultrasonic reception signal.
A transport control unit that controls the transport and stop of the sheet,
An image reader that reads the image on the sheet and
An image memory unit that captures the read data of the image read by the image reading unit, and an image memory unit.
In a state where the sheet is passing between the sound wave transmitting unit and the sound wave receiving unit, a sound wave transmitting control unit that controls the sound wave transmitting unit to stop the transmission of ultrasonic waves in response to a stop of transporting the sheet, and a sound wave transmitting control unit. equipped with a,
The transfer control unit is in a state where the sheet is passing between the sound wave transmitting unit and the sound wave receiving unit, and when there is no free area for capturing the read data in the image memory unit, or to the transfer destination. An image reading device, characterized in that the transfer of a sheet is stopped when the reading data is waiting to be transferred.

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