JPS62249852A - Detecting method for duplicate feed of cut sheet and mixing of different-type sheet - Google Patents

Abstract

PURPOSE:To detect the duplicate feed or the mixing of a differenttype sheet by allowing sheets to pass a detecting optical system in sequence, determining the average value of permeated light quantities at multiple sample points for each sheet, and checking whether the measured value of the inserted sheet is different from the average value. CONSTITUTION:No specific reference value is set, average values of permeated light quantities at multiple sample points for each sheet are averaged in sequence, this average value is compared with the average value at sample points for the next sheet, and if this difference is outside the predetermined range, the duplicate feed or the mixing of a different-type sheet is judged. When the permeated light quantity is remarkably increased or decreased due to the breakage, contamination, etc. of the sheet, it gives a large impact to the average value of permeated light quantities, thus this sample value is discarded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for detecting double feeding or mixing of different types of sheets in a paper conveyance system that separates cut sheets one by one and conveys them sequentially.

(Prior Art) In banknote counters and the like, it has conventionally been common to detect double feeding or mixing of different types of banknotes by utilizing variations in the amount of light that passes through the banknotes.

However, the double feed detection system that uses fluctuations in the amount of transmitted light as described above assumes in advance a reference amount of light that passes through a specific banknote, and if the amount of transmitted light decreases significantly from the reference value, double feed is detected. If the type of banknotes to be counted changes, it is necessary to change the setting of the reference value, which is cumbersome to operate, and the detection optical system changes over time. Since its characteristics change due to dirt or temperature fluctuations, there is a high possibility of malfunction and frequent maintenance is required.

In order to solve this problem, the inventor of the present application has already calculated the average value of the amount of transmitted light at multiple sample points on each sheet,
The average value of the transmitted light amount of each sheet is calculated in sequence, and the average value is compared with the average value of the transmitted light amount of multiple sample points of the next sheet, and the value is significantly lower or higher than the average value of each sheet. The idea is to determine that if a value exists, it is due to electrical transmission or foreign contamination, or to calculate the value by adding the absolute value of the difference between adjacent values of transmitted light amount at multiple sample points on each sheet. Sequentially calculate the average value and compare this average value with the value obtained by adding the absolute value of the difference between adjacent values of transmitted light amount of multiple sample points on the next sheet,
We have applied for a patent on the idea that if there is a value significantly lower or higher than the above average value, it will be determined as double feeding or contamination of different types, but even with this method, there will be cases where the sheet is damaged at the sample point, etc. If the sample point crosses the edge of the sheet due to defects or slips in the sheet conveyance system, or if the sheet is soiled with ink, etc., the amount of transmitted light will significantly increase or decrease, and the amount of transmitted light will decrease. There is a defect in that the light amount has a large effect on the average value of the amount of transmitted light at a plurality of sample points on each sheet, or the sum of the absolute values of the differences between adjacent values of the amount of transmitted light, and there is a possibility of malfunction. Ta.

(Object of the Invention) The present invention has been made in order to eliminate the defects of the double feed detection device using the conventional transmission optical system as described above. In addition to being able to perform double feed detection, the double feed detection rate is less affected by changes in the characteristics of the optical system, and frequent maintenance is not required, and there is no possibility of malfunction due to sheet damage, slipping, or staining. The purpose of the present invention is to provide a method for detecting double feeding of cut sheets and mixing of different types of sheets with less □.

(Summary of the Invention) In order to achieve the above-mentioned object, the method for detecting double feeding and mixing of different types of sheets according to the present invention is performed as follows.

That is, the sheets fed into the device are sequentially passed through the detection optical system, the average value of the transmitted light amount at multiple sample points of each sheet is calculated, the average value of the transmitted light amount of each sheet is sequentially calculated, and the average value of the transmitted light amount of each sheet is calculated. Compare the average value of transmitted light amount of multiple sample points of the next sheet, and if the value is significantly lower or higher than the average value of each sheet, double feeding or mixing of different types is detected, or The absolute value of the difference between adjacent values of the amount of transmitted light of multiple sample points on each sheet is added to obtain a value, and the average of these values is calculated sequentially. When comparing the sum of the absolute values of the differences between adjacent values of the amount of transmitted light, and if the value is significantly lower or higher than the average value, it is determined that there is double feeding or contamination of different types. If the amount of transmitted light at a sample point on the next sheet has a value significantly higher or lower than the average value of the amount of transmitted light at a plurality of sample points on each sheet, the transmitted light 1 of that sample point is removed. The average value of the amount of transmitted light of the secondary sheet or the sum of the absolute values of the differences between adjacent values is calculated, and this value is used to detect double feeding or mixing of different types.

(Example) The present invention will be described in detail below based on an example shown in the drawings.

Figure 2 is a diagram showing the general configuration of a banknote container to which the method for detecting double feeding and mixing of different types according to the present invention is applied.

In the figure, reference numeral 1 denotes a stacker for banknotes to be counted, and a feed roll 2 sends out banknotes one by one and deposits them in a stocker 3. A light emitting element 4 and a light receiving element 5 are provided facing each other near the feed roll 2, and when a banknote passes between these two, the amount of transmitted light is measured at a predetermined sample point on the two banknotes. The amount of transmitted light is measured using the light receiving element 5.
The output of CPtJ is passed through amplifier 6 and A/D converter 7.
8 and performs necessary calculations. Here, the presence or absence of double feeding is determined, and if it is determined that double feeding is occurring, the power supply circuit 10 of the drive system 9 of the feed roll 2 is shut off. Conventionally, the method of determining the presence or absence of double feeding is to assume in advance a reference amount of light that passes through a specific banknote, and if the amount of transmitted light is significantly lower than the reference value, it is determined that double feeding has occurred. Therefore, if the type of banknotes to be counted changes, it is necessary to change the setting of the reference value, which is cumbersome to operate, and the detection optical system is subject to aging, dirt, or temperature fluctuations. As mentioned above, there is a high possibility of malfunction because the characteristics vary depending on the paper, and furthermore, the double feed detection rate is greatly affected by sheet damage, slippage, or staining.

In order to solve this problem, the following method is used in the present invention.

First, without setting a specific reference value, the average value of the amount of transmitted light at multiple sample points on each sheet is sequentially averaged, and this average value is compared with the average value of the amount of transmitted light at multiple sample points on the next sheet. If the value falls outside the predetermined threshold above or below the average value, it is determined that there is double feeding or a different type of sheet is mixed in. If the sheet is damaged, etc., a sample is taken by step 7. If the point straddles the edge of the sheet, or if the sheet is soiled with ink, etc., the amount of transmitted light will significantly increase or decrease, and this will greatly affect the average value of the amount of transmitted light of each sheet. Compare the transmitted sight of multiple sample points of the sheet with the average value of the transmitted light amount of each sheet up to the previous sheet, and if there is a value significantly higher or lower than the average value, that sample value is is removed and the averaged value is used as the average value of the transmitted view of the 9th sheet to detect double feeding and mixing of different types of sheets.

By doing this, it is possible to eliminate abnormal values of the amount of transmitted light due to sheet damage, slippage, or staining, and the possibility of erroneous detection of double feeding and mixing of different types of sheets is extremely reduced.

The procedure of the above processing is as shown in the flowchart of FIG. 1 (at).

The above has only described the method of detecting double feeding and mixing of different types of sheets by sequentially averaging the average value of the amount of transmitted light at multiple sample points of each sheet. This method may also be applied to the case of detecting double feeding and mixing of different types of sheets by sequentially averaging the sum of the absolute values of the differences between adjacent values. The processing procedure in this case is shown in Figure 1 (
This is as shown in the flowchart b).

Note that the average value of the amount of light passing through the plurality of sample points of each sheet described above may be calculated using an arithmetic mean or a geometric mean.

In addition, as a method of adding the average value of the light transmission signal at a plurality of sample points of each sheet or the absolute value of the difference between adjacent values and sequentially averaging the nine values, each of the above-mentioned @1[1
(As shown in cl and (d), the average value of the transmitted scenes from the 1st frame to the mth frame or the value obtained by adding the absolute value of the difference may be simply arithmetic averaged, or (e) and (f)
As shown in , the average of the first and second sheets and the average value of the transmitted light amount of the third sheet or the sum of the absolute value of the difference are averaged and 1
Then, a method may be used in which the average value of the amount of transmitted light of the fourth wc sheet or the added value of the absolute value of the difference is calculated.

Alternatively, as shown in [g) and (hl) of the same figure, the geometric mean of the first and second sheets and the sum of the average value or absolute value of the difference of the amount of transmitted light of the third sheet is the geometric mean. death.

Then, a method may be used in which the geometric mean of this and the average value of the amount of transmitted light of the fourth sheet or the added value of the absolute value of the difference may be calculated.

Although only the case in which the present invention is applied to a banknote number counter has been described above, it goes without saying that the present invention can also be applied to devices that identify various cut sheets or count the number of sheets, such as a banknote identification device.

(Effects of the Invention) Since the present invention detects double feeding of cut sheets and mixing of different types of sheets using the method described above, there is no need to set judgment criteria for specific sheets, so different types of sheets can be processed. Even in the event of an accident, there is no need to re-set the standards, and the system is easy to operate and there is no risk of erroneous operation1.
,.

There is fruit. Furthermore, since double feeding is not detected based on specific predetermined criteria, it is not affected by changes in characteristics due to aging, dirt, or temperature fluctuations in the optical system, so there is no possibility of malfunction. It is possible to extend the interval between maintenance and remove abnormal values of the amount of transmitted light at sample points due to sheet damage, slipping, or staining, which reduces the possibility of erroneous detection of double feeding or mixing of different types of sheets. It also has the effect of becoming.

[Brief explanation of drawings]

FIG. 1 (at and (bl) are flowcharts for explaining different basic methods of detecting double feeding of cut sheets and mixing of different sheets according to the present invention, respectively, and FIGS. 1 (cl to (hl)
2 are flowcharts illustrating different transmitted light amount averaging methods used in the present invention, and FIG. 2 is a diagram showing the configuration of a banknote counter to which the present invention is applied. Patent applicant: Toyo Tsushinki Co., Ltd. Figure l ((2)

Claims (9)

[Claims] (1) The mth sheet (m=1, 2,
The average value of the amount of light transmitted through multiple sample points of each cut sheet up to The average value after removing multiple sample values of the m+1th cut sheet is the mth
The average amount of transmitted light of the +1st cut sheet is compared, and this average value is compared with the average value up to the mth cut sheet, and the average value for the m+1th cut sheet is above and below that of the mth cut sheet. Double feeding of cut sheets characterized in that when the threshold for detecting double feeding or mixing of different types of sheets is exceeded, the (m+1)th sheet is detected as a double feeding or a different type of sheet. and a method for detecting the mixing of different types of sheets. (2) The mth sheet (m=1, 2,
The sum of the absolute values of the differences between adjacent values of the amount of light transmitted through the plurality of sample points of each cut sheet up to 3...) is sequentially averaged. Remove multiple sample values of the m+1 cut sheet that are outside the threshold set in advance to remove abnormal values above and below the average value of the amount of light transmitted through the sample points. Calculate the value by adding the absolute value of the difference between adjacent values, and add this and the m
The average value up to the mth cut sheet is compared, and the value for the m+1 cut sheet is set above and below the average value up to the mth sheet from a predetermined threshold for detecting double feeding or mixing of different types of sheets. A method for detecting double feeding of cut sheets and mixing of different kinds of sheets, characterized in that, if the cut sheets are separated, the m+1th sheet is detected as a double feed or a different kind of sheet. (3) Claim (1) characterized in that the average value of the amount of light transmitted through a plurality of sample points of each cut sheet is calculated using an arithmetic mean or a geometric mean.
Or the method for detecting double feeding of cut sheets and mixing of different types of sheets as described in (2). (4) Average value L_i (i=1,
2,..., m; m=1, 2,...) is the average of (L_1+
The method for detecting double feeding of cut sheets and mixing of different types of sheets according to claim (1) or (2), characterized in that the method is executed based on the formula: L_2+...+L_m)/m. (5) A value T_i (i=1, 2, . . . , m; m=
The average of 1, 2, ...) is (T_1+T_2+...+T_
The method for detecting double feeding of cut sheets and mixing of different types of sheets according to claim (2), characterized in that the method is executed based on the formula: m)/m. (6) Average value L_i (i=1,
2, ..., m; m = 1, 2, ...) average value M_m is M
_m=L_m (m=1), M_m=(L_m+M_m_
-_1)/2 (m=2, 3,...)
2) Method for detecting double feeding of cut sheets and mixing of different types of sheets. (7) A value T_i (i=1, 2, . . . , m; m=
1, 2, ...), the average value U_m of U_m=T_m(m=
1), U_m=(T_m+U_m_-_1)/2(m=
2, 3, ...) A method for detecting double feeding of cut sheets and mixing of different types of sheets according to claim 2, wherein the method is executed based on the following equations. (8) Average value L_i (i=1,
2, ..., m; m = 1, 2, ...) average value M_m is M
_m=L_m (m=1), M_m=√(L_m×M_m
Claim (1) or (2) is characterized in that the method is executed based on the formula (m=2, 3, . . .)
) Method for detecting double feeding of cut sheets and mixing of different types of sheets. (9) A value T_i (i=1, 2, . . . , m; m=
1, 2, ...), the average value U_m of U_m=T_m(m=
1), U_m=√(T_m×U_m_-_1)(m=2
, 3, .