JPH069106A - Double feeding detecting circuit for paper sheet, etc. - Google Patents

Abstract

PURPOSE:To reduce control processing load by eliminating the need for adjusting work for a double feeding detecting part. CONSTITUTION:A transmitted luminous energy measuring part 1 measures the sheet transmitted luminous energy of a carrying document. An amplifier 2 voltage-converts a measuring value voltage with a constant magnification. A white reference memory part 4 previously stores street transmitted luminous energy value information at the time of no document carrying. A reference value correcting part 5 compares white reference information from the white reference memory part 4 with sheet transmitted luminous energy value information corresponding to street thickness from a carrying control part 8. The reference correcting part 5 forms its comparative arithmetic result into white reference variation portion to correct the A/D conversion reference value set in a reference value setting part 6. An A/D converting part 7 outputs the transmitted luminous energy measured value of the carried document as street thickness value information from the corrected A/D conversion reference value. A carrying control part 8 compares the sheet thickness value information with the double feeding value information from a sheet thickness memory part 8 to detect the double feeding of the document.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet double feed detection circuit, and more particularly to a sheet double feed detection circuit in OCR (optical character reading device) document conveyance.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of a conventional double feed detection circuit for paper sheets.

The double feed detection circuit in the optical character reader of this embodiment is an amplifier having a transmitted light amount measuring unit 1 for photoelectrically converting the amount of transmitted light on a sheet of paper and a variable resistor 11 for adjusting the measured voltage. 2 and. The measured amount of transmitted light is then A / D based on the analog / digital conversion (hereinafter A / D conversion) reference value set in the reference value setting unit 6.
An electric signal is converted by the D converter 7.

The transport controller 8 refers to the converted output value of the A / D converter 7 as paper thickness value information. At this time, in the amplifier 2, the variable resistor 11 is adjusted so that the paper thickness value information obtained by conveying the standard form (adjustment form) in which the paper thickness is defined in advance becomes a specified value. The paper thickness storage unit 9 stores paper thickness information (double feed value information) at the time of double feeding of documents.
Is stored. The presence / absence of double-feeding of documents is determined by the conveyance control unit 8 by comparing and calculating the double-feed value information and the sheet thickness information output from the A / D conversion unit 7.

[0005]

In the double feed detection circuit in the conventional optical character reading device, the transmitted light amount measurement value fluctuates due to the characteristic deviation of circuit components, the temporal change, and the ambient environment. Adjustment with a variable resistor using an adjustment form is required.

Further, in order to detect the presence / absence of double feed, it is necessary to perform a complicated process of referring to and comparing the previously registered double feed value information and the actually measured sheet thickness value information, respectively. There is a problem.

[0007]

SUMMARY OF THE INVENTION A double-feed detection circuit for paper sheets according to the present invention is a white reference for storing paper-transmitted light quantity value information measured by a sensor on a conveyance path for conveying paper sheets in the absence of paper. The storage unit includes a storage unit and a reference value correction unit that calculates a reference value used for an electric signal conversion process when the paper sheet is conveyed.

Then, a double feed determining section for detecting the presence or absence of double feed based on the value of the amount of light transmitted through the paper may be added.

[0009]

The present invention will be described below with reference to the drawings. 1 and 2 are block diagrams showing first and second embodiments of a double feed detection circuit for paper sheets according to the present invention.

In the first embodiment, the transmitted light amount measuring unit 1 photoelectrically converts the measured value after measuring the sheet transmitted light amount of the conveyed form. The amplifier 2 converts the measured value voltage into a voltage by a fixed factor by the added fixed resistor 3. The white reference storage unit 4 stores in advance the sheet transmitted light amount value information (white reference information) when the form is not conveyed (state where the form is not present). The reference value correction unit 5 compares the white reference information from the white reference storage unit 4 with the sheet transmitted light amount value information according to the sheet thickness of the form defined by the transport control unit 8.

Further, the reference value correction unit 5 uses the calculated result as the white reference variation amount, corrects the A / D conversion reference value set in the reference value setting unit 6, and outputs it to the A / D conversion unit 7. . A
The / D conversion unit 7 converts the transmitted light amount measurement value of the transport form into an electric signal from the corrected A / D conversion reference value and outputs it as paper thickness value information. The conveyance control unit 8 compares and calculates the paper thickness value information and the multi-feed value information stored in the paper thickness storage unit 9 to perform the multi-feed detection process of the form.

Next, the second embodiment has a configuration in which the double feed determining section 10 is added to the circuit configuration of the first embodiment.

First, when the form is conveyed, the amount of transmitted light of the form is measured by a procedure similar to the procedure in the first embodiment described above, and the paper thickness value information is output from the A / D converter 7. The multi-feed determination unit 10 refers to the multi-feed value information read from the paper thickness storage unit 9 in synchronization with the input of the paper thickness value information, and immediately outputs the determination information of the presence or absence of the multi-feed to the conveyance control unit 8 from the comparison result. Output.

[0014]

As described above, according to the present invention, in the double feed detection circuit of the optical character reading device, it is possible to correct the fluctuation of the measured value of the transmitted light amount of the form. Has the effect of becoming unnecessary. Further, by separating the form multifeed determination process from the transport control unit, there is an effect of reducing the transport control process load.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a double feed detection circuit for paper sheets according to the present invention.

FIG. 2 is a block diagram showing a second embodiment of a double feed detection circuit for paper sheets according to the present invention.

FIG. 3 is a block diagram showing an example of a conventional double feed detection circuit for paper sheets.

[Explanation of symbols]

 1 Transmitted light amount measuring unit 2 Amplifier 3 Fixed resistor 4 White reference storage unit 5 Reference value correction unit 6 Reference value setting unit 7 A / D conversion unit 8 Transport control unit 9 Paper thickness storage unit 10 Double feed determination unit

Claims (2)

[Claims] 1. A white reference storage unit for storing information about the amount of transmitted light of a paper measured by a sensor on a conveyance path for conveying the paper without a paper, and used for an electric signal conversion process when the paper is conveyed. A double feed detection circuit for paper sheets, comprising: 2. The double-feed detection circuit for paper sheets according to claim 1, further comprising a double-feed determination unit that detects the presence or absence of double-feed based on the value of the amount of light transmitted through the paper.