JP2010180009A - Sheet feed supply device and image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feed supply device capable of reducing the number of part items and the number of terminals constituting a circuit, to reduce a cost by making common a part of the circuits constituting a sheet detecting means and a double feed detecting means. <P>SOLUTION: The sheet feed supply device includes a light transmission type sensor S3 having a light emitting part S3-a and a photoreception part S3-b oppositely arranged in a position with a conveying route of a sheet L1 therebetween, an ultrasonic sensor S4 having a transmission part S4-a and a reception part S4-b oppositely arranged in a position with the conveying route of the sheet L1 therebetween, a control means B04 for detecting the sheet L1 conveyed on the conveying route based on an output signal from the photoreception part S3-b, and detecting the double feed of the sheet L1 conveyed on the conveying route based on an output signal from the reception part S4-b, and a drive means B01 for outputting the same drive signal to the light emitting part S3-a and the transmission part S4-a by the control of the control means B04. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus such as a scanner, or a sheet feeding apparatus mounted on an image forming apparatus such as a printer, a facsimile, or a copying machine, and an image reading apparatus including the sheet feeding apparatus.

  As a conventional sheet feeding apparatus of this type, as shown in FIG. 10, it is detected that a sheet L1 is being conveyed using a light transmission type sensor S3, and an ultrasonic sensor detects double feeding of the sheet L1. There exists what detects using S4 (patent document 1).

  The light transmission type sensor S3 includes a light emitter S3-a and a light receiver S3-b that are arranged opposite to each other at a position across the conveyance path of the sheet L1, and the ultrasonic sensor S4 is located at a position across the conveyance path of the sheet L1. A transmitter S4-a and a receiver S4-b are provided opposite to each other.

  The light emitted from the light emitter S3-a of the light transmission type sensor S3 does not pass through the sheet L1 when the sheet L1 exists in the conveyance path, and receives the light receiver S3-b when the sheet L1 does not exist in the conveyance path. Is received.

  The control circuit A07 supplies a light emission signal to the light emitter drive circuit A02 to cause the light emitter S3-a to emit light and to control the amount of light emitted. Since the light output from the light receiver S3-b when the light emitted from the light emitter S3-a is received by the light receiver S3-b is very small, the output signal is amplified by the amplifier circuit A03. The signal level is raised to a level at which the difference in the amount of transmitted light can be analyzed. The analog signal amplified by the amplifier circuit A03 is converted into a digital signal by the A / D converter A05 and output to the control circuit A07.

  The control circuit A07 outputs a light emission signal having a waveform P shown in FIG. 11 to the light emitter S3-a via the light emission drive circuit A02. Further, a signal output when the light receiver S3-b receives the light emitted from the light emitter S3-a is amplified by the amplifier circuit A03, and is converted into the A / D converter A05 as the light reception signal Q shown in FIG. To the control circuit A07.

  When the conveyed sheet L1 reaches between the light emitter S3-a and the light receiver S3-b, the light reception signal Q is greatly attenuated, and the control circuit A07 controls the paper of the sheet L1 based on the attenuation amount of the light reception signal. The presence or absence of the edge and the sheet L1 is detected.

  Further, the ultrasonic wave transmitted from the transmitter S4-a of the ultrasonic sensor S4 passes through the sheet L1 and is received by the receiver S4-b when the sheet L1 exists in the conveyance path, and the sheet L1 in the conveyance path. Is not received directly by the receiver S4-b.

  The control circuit A07 supplies a pulse signal having a period of, for example, 300 KHz to the ultrasonic transmitter drive circuit A01, and the transmitter S4-a is based on the pulse signal amplified by the ultrasonic transmitter drive circuit A01, Send sound waves.

  When the sheet L1 arrives between the transmitter S4-a and the receiver S4-b, the ultrasonic wave transmitted from the transmitter S4-a is attenuated before reaching the receiver S4-b. For this reason, the signal output from the receiver S4-b that has received the ultrasonic wave is amplified by the amplifier circuit A04 and raised to a signal amplitude that allows determination of double feed detection. The analog reception signal amplified by the amplifier circuit A04 is converted into a digital signal by the A / D converter A06 and output to the control circuit A07.

  The control circuit A07 outputs an ultrasonic wave transmission signal having a waveform R shown in FIG. 12 to the transmitter S4-a via the ultrasonic wave transmission drive circuit A01. After that, the reception signal having the waveform S shown in FIG. 12 received by the receiver S4-b and amplified by the amplifier circuit A04 after a time y delayed from the transmission signal by the speed of sound is supplied to the control circuit via the A / D converter A06. It is output to A07.

  When the sheet L1 is double-fed and conveyed on the conveyance path, the ultrasonic wave reaching the receiver S4-b is greatly attenuated by the air layer of the overlapping portion of the sheet L1, so that the control circuit A07 Based on the attenuation of the received signal, the presence / absence of double feeding of the sheet L1 is detected.

JP 2004-231403 A

  However, in the conventional sheet feeding apparatus, a dedicated circuit is required between the light transmission type sensor S3 and the control circuit A07 and between the ultrasonic sensor S4 and the control circuit A07. This increases the number of parts and the number of terminals, which hinders cost reduction.

  Therefore, the present invention makes it possible to reduce costs by reducing the number of parts and terminals constituting the circuit by sharing a part of the circuit constituting the sheet detection means and the double feed detection means. It is an object of the present invention to provide a feeding device and an image reading device including the sheet feeding device.

  In order to achieve the above object, a sheet feeding apparatus according to the present invention includes a light transmission type sensor having a light emitting portion and a light receiving portion arranged to face each other at a position sandwiching the sheet conveyance path, and a position sandwiching the sheet conveyance path. Based on an ultrasonic sensor having a transmitter and a receiver disposed opposite to each other and a light reception signal output from the light receiver, a sheet conveyed on the conveyance path is detected and output from the receiver. Control means for detecting double feeding of sheets conveyed along the conveyance path based on a received signal, and drive means for outputting the same drive signal to the light emitting section and the transmission section under the control of the control means It is characterized by providing.

  An image reading apparatus according to the present invention is an image reading apparatus that reads an image of a sheet fed to a conveyance path by a sheet feeding apparatus, and the sheet feeding apparatus is described in any one of claims 1 to 4. The sheet feeding device described is used.

  According to the present invention, since a part of the circuit constituting the sheet detecting means and the double feed detecting means can be shared, the number of parts and the number of terminals constituting the circuit can be reduced and the cost can be reduced. it can.

FIG. 3 is a block diagram for explaining a sheet feeding apparatus which is an example of an embodiment of the present invention. It is a figure which shows the circuit structural example of a sheet | seat detection means and a double feed detection means. It is a figure which shows an example of the waveform of the drive signal with respect to a light emitter and a transmitter, and the waveform of the signal output to a control circuit from a light receiver and a receiver. It is a figure which shows an example of a drive circuit. 1 is a configuration diagram of a drive circuit in Embodiment 1. FIG. It is a figure which shows the signal waveform output with respect to a light-emitting device from a drive circuit when a drive signal is output to a drive circuit from a control circuit. It is a figure which shows the signal waveform output with respect to a light-emitting device from a drive circuit when a drive signal is output to a drive circuit from a control circuit. It is a figure which shows the example of a waveform of the drive signal at the time of driving only a sheet | seat detection means. It is a figure which shows the example of a waveform of the drive signal at the time of driving only a double feed detection means. It is a figure which shows the example of a waveform of the drive signal at the time of driving both a sheet | seat detection means and an ultrasonic multifeed detection means with the same drive signal. It is a block diagram for explaining a conventional sheet feeding apparatus. It is a figure which shows the example of a waveform of a light emission signal and a light reception signal. It is a figure which shows the example of a waveform of a transmission signal and a received signal.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram for explaining a sheet feeding apparatus which is an example of an embodiment of the present invention. In the present embodiment, an image reading apparatus such as a scanner or a sheet feeding apparatus mounted on an image forming apparatus such as a printer, a facsimile, or a copying machine is taken as an example, but the present invention is not limited to this.

  As shown in FIG. 1, the sheet feeding apparatus according to the present embodiment uses a light transmission type sensor S3 to detect that the sheet L1 is being conveyed, and ultrasonically detects double feeding of the sheet L1. And a double feed detecting means for detecting using the sensor S4.

  The light transmission type sensor S3 includes a light emitter (light emitting unit S) 3-a and a light receiver (light receiving unit) S3-b that are disposed to face each other across the conveyance path of the sheet L1. The ultrasonic sensor S4 includes a transmitter (transmitting unit) S4-a and a receiver (receiving unit) S4-b that are arranged opposite to each other at a position across the conveyance path of the sheet L1.

  The light emitter S3-a of the light transmission type sensor S3 and the transmitter S4-a of the ultrasonic sensor S4 are connected to the control circuit B04 via a common drive circuit B01. The light receiver S3-b of the light transmission sensor S3 and the receiver S4-b of the ultrasonic sensor S4 are connected to the control circuit B04 via a common amplifier circuit B02 and a common A / D converter B03. The

  The control circuit B04 supplies a drive signal to the drive circuit B01 to drive the light emitter S3-a and the transmitter S4-a, whereby light is emitted from the light emitter S3-a and the transmitter S4. -A transmits ultrasonic waves.

  When the light emitted from the light emitter S3-a reaches the light receiver S3-b, the signal output from the light receiver S3-b and the ultrasonic wave transmitted from the transmitter S4-a are received by the receiver S4-b. The signal that is output from the receiver S4-b when the signal reaches is very small.

  For this reason, the signal output from the light receiver S3-b and the signal output from the receiver S4-b are amplified via the common amplifier circuit B02, so that the sheet can be detected and the double feed can be detected. Raised to level. The analog signal amplified by the amplifier circuit B02 is converted into a digital signal by the A / D converter B03 and output to the control circuit B04.

  FIG. 2 is a diagram illustrating a circuit configuration example of the sheet detection unit and the double feed detection unit.

  When a drive signal is output from the control circuit B04 to the light emitter S3-a and the transmitter S4-a via the drive circuit B01, the output waveforms shown in FIG. 3 are output from the light emitter S3-a and the transmitter S4-a. can get.

  As shown in FIG. 3, the light emitter S3-a and the transmitter S4-a are configured to output the number of drive signals necessary for the control circuit B04 to obtain a signal level for detecting a sheet and detecting a double feed. Is different. For example, the light emitter S3-a requires one drive signal, whereas the transmitter S4-a requires five drive signals.

  For this reason, in the present embodiment, the drive circuit B01 can output drive signals of a number of times suitable for the light emitter S3-a and the transmitter S4-a.

  The control circuit B04 outputs a signal having the waveform 303a shown in FIG. 3 to the light emitter S3-a via the drive circuit B01, and outputs a signal having the waveform 304b shown in FIG. 3 to the transmitter S4-a. To do. The signal output from the light receiver S3-b and the signal output from the receiver S4-b are each amplified by the common amplifier circuit B02. The light reception signal 303b and the reception signal 304b amplified by the amplifier circuit B02 are output to the control circuit B04 via the common A / D converter B03.

  At this time, the light emitter S3-a and the transmitter S4-a are driven by the same drive signal. Therefore, although the driving timings for light emission and transmission are the same, the timing at which the light from the light emitter S3-a reaches the light receiver S3-b and the ultrasonic wave from the transmitter S4-a reach the receiver S4-b. As shown in FIG. 3, a certain time difference z is generated. For this reason, in the sheet detection means and the double feed detection means, even if the drive circuit B01, the amplifier circuit B02, and the A / D converter B03 are shared, the output signals from the light receiver S3-b and the receiver S4-b are mutually connected. There is no impact.

  When the conveyed sheet L1 arrives between the light emitter S3-a and the light receiver S3-b, the light reception signal 303b is greatly attenuated, and the control circuit B04 determines whether the sheet L1 is based on the attenuation amount of the light reception signal 303b. The presence or absence of the paper edge and sheet L1 is detected. Further, when the sheet L1 is double-fed and conveyed on the conveyance path, the ultrasonic wave reaching the receiver S4-b is greatly attenuated by the air layer of the overlapping portion of the sheet L1, so that the control circuit B04 The presence / absence of double feeding of the sheet L1 is detected based on the attenuation amount of the sound wave reception signal 304b.

  FIG. 4 is a diagram illustrating an example of the drive circuit B01. 5 and 6 are diagrams showing waveforms of output signals to the light emitting device S3-a when the drive signal output from the control circuit B04 is input to the drive circuit B01 of FIG.

  In the time zone T1 in FIG. 5, when the Low signal 509a is output from the control circuit B04 to the input unit 9a of the drive circuit B01 shown in FIG. 4, the High signal 509b obtained by inverting the Low signal 509a in the inverting unit 9b in FIG. Is output. At this time, a high signal 509c is also output from the output unit 9c in the same manner as the inversion unit 9b, and a logical product of signals from the input unit 9a and the output unit 9c is output as a low signal 509d from the logical product unit 9d to the light emitter S3 -A is output.

  In the time zone T2, the high signal 509a is output from the control circuit B04 to the input unit 9a of the drive circuit B01 shown in FIG. 4, and accordingly, the low signal 509b is output from the inversion unit 9b. Here, since the output unit 9c is provided with a capacitor, the signal level changes more slowly on the Low level side than the inversion unit 9b. Therefore, the signal determination of the signal 509c is a High signal determination. As a result, in the time zone T2, since the signal levels at the input unit 9a and the output unit 9c are both high signals, the high signal 509d is output from the logical product unit 9d. Thereby, a drive signal is output from the drive circuit B01 to the light emitter S3-a, and light is emitted from the light emitter S3-a.

  In the time zone T3, the signal level 509a in the input unit 9a and the signal level 509b in the inversion unit 9b are the same as those in the time zone T2. As shown in FIG. 5, the output unit 9c enters the Low signal determination region, the signal level gradually changes as it is, the capacitance accumulated in the capacitor is released, and the signal level 509c becomes a completely Low signal. As a result, a low signal 509d is output from the logical product unit 9d. As a result, the drive signal from the drive circuit B01 to the light emitter S3-a is not output, and the light emitter S3-a is turned off.

  In the time zone T4, the low signal 509a is output from the control circuit B04 to the input unit 9a, and accordingly, the high signal 509b is output from the inversion unit 9b. At this time, the signal level at the output unit 9c becomes a high level, but first, since electric charge is accumulated in the capacitor, the signal level gradually changes toward the high signal level as shown in FIG. A low signal 509d is output from the logical product unit 9d.

  In the time zone T5, the signal levels 509a and 509b in the input unit 9a and the inverting unit 9b are the same as those in the time zone T4. At this time, in the output unit 9c, the signal level tends to become a high level as in the time zone T4, but the signal level gradually changes due to the accumulation of electric charges in the capacitor. Is a Low signal determination. As a result, a low signal 509d is output from the logical product unit 9d.

  In the time zone T6, the high signal 509a is output from the control circuit B04 to the input unit 9a, and accordingly, the low signal 509b is output from the inversion unit 9b. As a result, the signal from the output unit 9c also changes to the low level, but the signal level gradually changes to low because of the capacity accumulated in the capacitor. As a result, the Low signal 509d is continuously output from the logical product unit 9d from the time zone T5.

  In time zone T7, the same operation as in time zone T3 described above is performed, and in time zone T8, the same operation as in time zone T4 described above is performed.

  As shown in FIG. 5, when the signal 509a at a constant interval is continuously output from the control circuit B04 to the input unit 9a, the high signal 509d is output from the logical product unit 9d only in the time zone T2. Thereafter, the light emitter S3-a continues to be turned off, and the drive signal 509a is output only to the transmitter S4-a.

  Next, a case where the signal output from the control circuit B04 to the input unit 9a of the drive circuit B01 is inverted with respect to FIG. 5 will be described with reference to FIG.

  In the time zone T1 of FIG. 6, when the High signal 609a is output from the control circuit B04 to the input unit 9a of the drive circuit B01, the inverting unit 9b outputs the Low signal 609b obtained by inverting the High signal 609a. At this time, the low signal 609c is output from the output unit 9c similarly to the inverting unit 9b, and the logical product of the signals from the input unit 9a and the output unit 9c is output from the logical product unit 9d as the low signal 609d to the light emitter S3. -A is output.

  In the time zone T2, the low signal 609a is output from the control circuit B04 to the input unit 9a, and accordingly, the high signal 609b is output from the inversion unit 9b. Here, since a capacitor is arranged in the output unit 9c, first, charges are accumulated in the capacitor, and the signal level gradually changes to the High signal level side. At this time, the signal determination level is Low signal determination, and as a result, the Low signal 609d is output from the AND unit 9d.

  In the time zone T3, the signal levels at the input unit 9a and the inverting unit 9b are the same as in the time zone T2. In the output unit 9c, as shown in FIG. 6, the signal gradually changes to the High signal level side, but the signal determination level does not reach the High signal level. The low signal 609d is output in the same manner as T2.

  In the time zone T4, the high signal 609a is output from the control circuit B04 to the input unit 9a, whereby the low signal 609b is output from the inversion unit 9b. At this time, in the output unit 9c, the signal changes while the electric charge accumulated in the capacitor is released, so that it gradually changes toward the Low signal level. As a result, a low signal 609d is output from the logical product unit 9d.

  In the time zone T5, the signal level in the input unit 9a and the inversion unit 9b is the same as that in the time zone T4. However, in the output unit 9c, the signal changes while the charge accumulated in the capacitor is released. As shown in FIG. 6, the signal gradually changes to the low signal level side. As a result, a low signal 609d is output from the logical product unit 9d.

  In the time zone T6 to the time zone T8, the same operation as the time zone T2 to the time zone T4 described above is performed.

  When the signal 609a shown in FIG. 6 is continuously output from the control circuit B04 to the input unit 9a, the light emitter S3-a continues to be extinguished, and a signal is output only from the drive circuit B01 to the transmitter S4-a. It will be.

  From the operations of FIGS. 5 and 6, the sheet detection unit and the multifeed detection unit can be arbitrarily selected and operated by a drive signal output from the control circuit B04 to the drive circuit B01.

  When only the sheet detecting means is operated, a drive signal 709a shown in FIG. 7 is output from the control circuit B04 to the drive circuit B01, so that a signal 709d necessary for driving is output from the drive circuit B01 to the light emitter S3-a. Is done. On the other hand, since the signal 719a output from the driving circuit B01 to the transmitter S4-a is not a signal that is sufficiently necessary for driving, as a result, only the sheet detecting means can be operated. In FIG. 7, a signal 709a corresponds to the input unit 9a, a signal 709b corresponds to the inverting unit 9c, a signal 709c corresponds to the output unit 9c, and a signal 709d corresponds to the logical product unit 9d.

  When only the double feed detection means is operated, for the reason described in FIG. 6, the drive signal 809a shown in FIG. 8 is output from the control circuit B04 to the drive circuit B01, so that the drive circuit B01 outputs the transmitter S4-a. On the other hand, a signal 819a necessary for driving is output. On the other hand, since the signal 809a is not output from the drive circuit B01 to the light emitter S3-a, only the double feed detection unit can be operated as a result. In FIG. 8, a signal 809a corresponds to the input unit 9a, a signal 809b corresponds to the inverting unit 9c, a signal 809c corresponds to the output unit 9c, and a signal 809d corresponds to the logical product unit 9d.

  Further, by outputting the drive signal 909a shown in FIG. 9 from the control circuit B04 to the drive circuit B01, a signal 909d necessary for driving each of the light emitter S3-a and the transmitter S4-a from the drive circuit B01. And a signal 919a can be output. In FIG. 9, a signal 909a corresponds to the input unit 9a, a signal 909b corresponds to the inverting unit 9c, a signal 909c corresponds to the output unit 9c, and a signal 909d corresponds to the logical product unit 9d.

  As described above, in the present embodiment, since the drive circuit B01, the amplifier circuit B02, and the A / D converter B03 can be shared in the sheet detection unit and the double feed detection unit, the components constituting the circuit Costs can be reduced by reducing the number of points and the number of terminals.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

L1 sheet S3 light transmission sensor S3-a light emitter S3-b light receiver S4 ultrasonic sensor S4-a transmitter S4-b receiver B01 drive circuit B02 amplifier circuit B03 A / D converter B04 control circuit

Claims (5)

A light transmissive sensor having a light emitting portion and a light receiving portion arranged opposite to each other at a position sandwiching the sheet conveyance path;
An ultrasonic sensor having a transmitter and a receiver disposed opposite to each other at a position sandwiching the sheet conveyance path;
Based on a light reception signal output from the light receiving unit, a sheet conveyed through the conveyance path is detected, and based on a reception signal output from the reception unit, double feeding of the sheet conveyed through the conveyance path is performed. Control means for detecting;
Drive means for outputting the same drive signal to the light emitting part and the transmitting part under the control of the control means. The sheet feeding apparatus according to claim 1, further comprising a common amplifying unit that amplifies the signal output from the light receiving unit and the signal output from the receiving unit. A conversion means for converting the analog signal output from the amplification means into a digital signal and outputting the digital signal to the control means;
The sheet feeding apparatus according to claim 2, wherein the sheet feeding apparatus is a sheet feeding apparatus. The drive means controls the light emitting section and the transmitting section with a signal for driving only the light emitting section, a signal for driving only the transmitting section, and the light emitting section and the transmitting section under the control of the control means. Select and output signals that drive both.
The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus. An image reading device that reads an image of a sheet fed to a conveyance path by a sheet feeding device,
As the sheet feeding device, the sheet feeding device according to any one of claims 1 to 4, is used.
An image reading apparatus.

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