JPH0558482B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

This invention detects dimensional abnormalities of approximately rectangular paper sheets, mainly banknotes, measured in the conveying direction.
Relating to a method in which photoelectric sensors arranged in an array in a direction perpendicular to the conveyance direction are divided into several groups, the dimensions are measured based on signals from each group, and detection is performed based on the measurements. .

[Prior art and its problems]

A conventional method for detecting dimensional abnormalities of approximately rectangular paper sheets, mainly banknotes, is as follows. 6th
In the figure, the banknote 9 is conveyed in the longitudinal direction of the arrow, and the longitudinal dimension of the banknote 9 is determined by two photoelectric sensors 1 arranged at appropriate intervals perpendicular to the conveyance direction.
It is obtained based on the shading time of 1. Further, the dimension in the width direction is determined by scanning the light-shielded state of the photoelectric sensors 1 arranged in an array in the width direction. Generally, dimensional abnormalities due to defects in banknotes often occur on the long sides of banknotes, so the above-described conventional method can be said to be appropriate. However, recently, the direction of conveyance of banknotes has increasingly been carried out in the width direction perpendicular to the longitudinal direction, that is, in the direction of the short side. This is because there has been a growing demand to improve banknote processing speed or increase the number of banknotes processed per unit time. In FIG. 7, it is insufficient to detect the dimension in the conveying direction of the banknote 9, that is, the dimension of the short side indicated by the arrow, with about two or three photoelectric sensors 11 as in the conventional method, and the photoelectric sensor 1 are arranged in an array, and it is necessary to detect the entire length. When considered as an extension of the conventional method, this method has the following two types. The first method is to detect the dimension in the transport direction using photoelectric sensors arranged in an array. The second method is to detect the dimensions by scanning the state of each photoelectric sensor arranged in an array. The first method requires as many dimension measuring circuits, such as counters, as the number of photoelectric sensors arranged in an array, which is not economical and has problems in practical use. Furthermore, the second method has the disadvantage that dimension measurement accuracy is not achieved because the scanning is performed in a direction perpendicular to the direction in which the measurement is to be made.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for detecting dimensional abnormalities in paper sheets based on a highly accurate and economical dimensional measuring method, which eliminates the problems of the conventional method.

[Key points of the invention]

The main points of the present invention to achieve the above objects are as follows:
The number of dimension detection circuits is reduced by dividing the photoelectric sensors arranged in an array in a direction perpendicular to the conveyance direction of paper sheets into several groups and collecting dimension information for each group. - It is based on the idea that That is, as shown in the block diagram of FIG. 1, the configuration of the present invention includes photoelectronics arranged linearly at approximately equal intervals over the entire width of the paper sheet in the width direction perpendicular to the conveying direction. With an appropriate number of photoelectric sensor groups Ga, Gb, Gc each consisting of an appropriate number of adjacent sensors 1, and a paper sheet presence detection signal from each photoelectric sensor 1 belonging to each photoelectric sensor group Ga, Gb, Gc, Each width determination circuit 2A, 2B, 2C outputs a normal width signal indicating that the width of the paper sheet corresponding to each of the photoelectric sensor groups Ga, Gb, Gc is normal, for example, the presence of the paper sheet. An AND circuit that outputs a normal width signal only when all of the detection signals are present, and each dimension detection circuit 3A, 3B, 3 that outputs a signal corresponding to the dimension in the conveying direction based on each of the normal width signals.
C, a counter that receives, for example, the regular width signal, a clock pulse, and a reset signal issued each time each paper sheet arrives; , for example, a common dimension that outputs a dimension abnormality signal only when this signal exceeds the upper and lower limit set values, or only when the difference between the maximum and minimum values in this signal exceeds a predetermined value. It is equipped with an abnormality determination circuit 4, and is capable of detecting an abnormality existing in any of the dimensions measured in the conveyance direction of paper sheets corresponding to each photoelectric sensor group Ga, Gb, and Gc. . Therefore, the present invention provides the dimension detection circuit 3A,
The number of sensors 3B and 3C only needs to be the number of photoelectric sensor groups Ga, Gb, and Gc, that is, three in this case. Moreover, the photoelectric sensor 1 covers the entire width, and the size detection is performed based on the light-blocking time due to conveyance of the paper sheet, so that the detection accuracy is good.

[Embodiments of the invention]

The embodiment described below with reference to the drawings relates to a method for detecting an abnormal width dimension when a banknote is conveyed in the direction of its short side. FIG. 2 is an explanatory diagram showing the arrangement of transported banknotes and photoelectric sensors in one embodiment, FIG. 3 is a time chart of the operation of each photoelectric sensor, and FIG. 4 is a block circuit diagram showing the configuration of one embodiment. FIG. 5 is an explanatory diagram showing a dimension detection error when a banknote is conveyed in an inclined manner. In FIG. 2, banknotes 9 are conveyed in the direction of arrow P, and photoelectric sensors 1 are arranged parallel to the longitudinal direction of the banknotes 9 so as to cover the entire width thereof. This photoelectric sensor 1 is, for example, a combination of a light emitting diode and a phototransistor. In the example shown in this figure, 15 photoelectric sensors 1 are arranged at equal intervals and equally divided into three groups G1, G2, and G3, and each group G1, G2, and G3 controls the length of the banknote 9 in the longitudinal direction. Detection of defective parts is shared. Each group includes five photoelectric sensors 1. Now, the front edge and the rear edge of the banknote 9 have defective parts F1 and F1, respectively.
Suppose there is F2. Next, photoelectric sensor 1 belonging to photoelectric sensor group G2
A, 1b, 1c, 1d, and 1e will specifically describe how the above-mentioned defective parts F1 and F2 are detected. The photoelectric sensors 1a, 1b, 1c, 1d, and 1e are
When the banknote 9 is transported, the bill 9 is initially in a light-receiving state, but is blocked by the front edge including the defective part F1 crossing it, and then returns to the light-receiving state by passing the trailing edge including the defective part F2. Become. In FIG. 2, broken lines drawn horizontally from the center of each photoelectric sensor represent lines of relative movement between the banknote 9 and each photoelectric sensor, and the points where they intersect with the edge lines of each defective part F1 and F2 are A1, B1, C1, D1, E1, A2,
Let them be B2, C2, D2, and E2. In addition, Lo is the length of the short side of the banknote 9, Lf1, Lf2 are the missing part F1,
Depth measured in the short side direction of E2, Ln is the dimension of the unbroken part measured in the short side direction, Ln=Lo−
(Lf1+Lf2). The state of light reception or light shielding of each photoelectric sensor or the voltage generated by light reception or light shielding is represented by symbols H and L, and the relationship between these and time is as shown in the time chart of FIG. Figure a shows the photoelectric sensor 1a, and similarly, Figures b to e show the states of the photoelectric sensors 1b to 1e. Note that the two vertical broken lines in FIG. 3 indicate when the front edge and rear edge of the banknote 9 cross the photoelectric sensors 1a to 1e. In other words, in the defect portion F1, the state changes from state H to state L with a time delay from the leading edge depending on the degree of the defect.
On the other hand, in the defective part F2, the state changes from L to H temporally earlier than in the trailing edge. Therefore, the time Tf during which all the photoelectric sensors 1a to 1e are shielded from light corresponds to the dimension Ln (see FIG. 2) of the portion without a defect, measured in the short side direction. In other words, while the bill 9 is passing from the front edge to the rear edge and any one of the photoelectric sensors 1a to 1e is receiving light, a defective portion exists. Next, the configuration of one embodiment will be explained with reference to the block circuit diagram of FIG. This block circuit diagram is
One photoelectric sensor group G2 among the three photoelectric sensor groups G1, G2, and G3 in Fig. 2, the corresponding width judgment circuit, dimension detection circuit, and common dimensional abnormality judgment circuit (see Fig. 1) It shows. From the left side of the figure, photoelectric sensors 1a belonging to one group G2 (see Figure 2) are arranged at equal intervals.
~1e, an input circuit 10 that converts the change in photoelectric current due to light reception into a voltage and further amplifies it; when the output from this input circuit 10 is an L active signal, when receiving this L active signal, an AND condition is satisfied; H
A NOR circuit 20 that outputs an active signal, a counter 30 that receives the output of this NOR circuit 20, a reset signal R corresponding to the arrival of banknotes, and a clock pulse CL, an upper limit comparator 40A that receives the output of this counter 30, and a lower limit comparator 40A. A container 40B is placed. With the above-mentioned components, photoelectric sensors 1a to 1
e, input circuit 10, NOR circuit 20, counter 3
Three sets are provided corresponding to the photoelectric sensor groups G1, G2, G3 (see FIG. 2) up to 0, and one set of comparators 40A, 40B below are provided in common. In addition, in this invention, the "width determination circuit" corresponds to the above-mentioned NOR circuit 20, the "dimension detection circuit" also corresponds to the counter 30, and the "dimensional abnormality determination circuit" similarly corresponds to the comparators 40A and 40B. The operation of the above-described embodiment shown in the block circuit diagram of FIG. 4 is as follows. Voltage signals are input to the NOR circuit 20 via the input circuit 10 from the photoelectric sensors 1a to 1e that receive and block light.
This NOR circuit 20 is an AND circuit having an L active input terminal and an H active output terminal, and outputs an H active signal when all the photoelectric sensors 1a to 1e are shielded from light and an L active signal is input. Therefore, the period during which the H active signal is output corresponds to the time Tf in FIG. 3, and at the same time corresponds to the dimension Ln in FIG. 2. Each time a banknote arrives, the counter 30 returns the count value to zero by a reset signal R.
In other words, a signal corresponding to the dimension Ln is output, which corresponds to the period Tf during which the above-mentioned H active signal is output. The output from the counter 30 is commonly input to the next two comparators 40A and 40B, and an upper limit set value and a lower set value are respectively input in advance. The comparator 40A is designed to output only when the value obtained by subtracting the output of the counter 30 from the upper limit setting value becomes negative. Similarly, the comparator 40B is designed to output only when the value obtained by subtracting the lower limit set value from the output of the counter 30 becomes negative. That is, the counter 30
A signal is output only when the output exceeds the upper and lower limit settings. Therefore, this output signal is a detection signal indicating a dimensional abnormality. As described above, in this embodiment, the photoelectric sensors 1a to 1e are arranged at regular intervals, and each photoelectric sensor group is composed of the same number of photoelectric sensors. This is because the probability of occurrence is the same no matter where on the long side it occurs. In addition, since it is provided with not only the upper limit comparator 40A but also the lower limit comparator 40B, the banknote 9 can be used not only when the bill 9 has a missing part exceeding the set value but also when it has an additional part exceeding the set value. Dimensional abnormalities can be detected. The above-mentioned sensor detects the dimensions while all of the photoelectric sensors 1a to 1e are shielded from light, and is suitable for banknotes. but,
In the case of general paper sheets, depending on the purpose, a defect with a small width, for example, a defect so small that only one photoelectric sensor receives light, may not be considered a "defect." There is also. In other words, the criteria for determining defective parts are relaxed. In this case, instead of the NOR circuit in FIG. 4, a summator and a comparator are arranged in series, and when the total value of the output from the input circuit 10 is, for example, 4L or more, an H active signal is output. All you have to do is output it. In addition, as mentioned above, instead of defining "dimensional abnormality" as when the absolute value of the dimension of the non-defective part measured in the conveyance direction exceeds the upper and lower limit set values, When the difference value exceeds a predetermined setting value, it may be set to -. This judgment method can be applied when the problem is the relative degree of deformation of the edge line due to the defect rather than the absolute value of the defect in the insulation, and although it is inappropriate for banknotes, it is suitable for general rectangular paper sheets. It can be taken in cases like this. Next, the dimension detection error when the banknote 9 is skewed in the direction of the arrow will be described with reference to FIG.
When a group of N photoelectric sensors 1 arranged in a straight line with an interval a detects a banknote 9 that is traveling diagonally as shown in the figure, even though the banknote 9 is not completely damaged, the non-defective part is detected. The dimension of is detected apparently as if it were Lm. In this case, if the apparent defect size is Lfm and the angle of inclination is θ, then when θ is small, Lfm=Lo−Lm=2a(N−1)θ This Lfm means that the banknote 9 will run diagonally. This can be said to be a dimension detection error caused by.

【Effect of the invention】

This invention divides photoelectric sensors arranged in an array in a direction perpendicular to the conveying direction of paper sheets into several groups, and collects dimension information for each group, thereby increasing the number of dimension detection circuits. reduce the
In other words, the number of dimension detection circuits is reduced only by the number of photoelectric sensor groups;
This is done based on the light-blocking time due to the conveyance of paper sheets. Therefore, the present invention has the following superior effects compared to the conventional one. (1) Size detection is performed based on the light-blocking time during paper sheet transportation, so detection accuracy is high. (2) It is economical because the number of dimension detection circuits is only the number of photoelectric sensor groups. Compared to the case where a dimension detection circuit is simply provided in correspondence to each photoelectric sensor, the number is significantly reduced. For example, if there are 40 photoelectric sensors and four groups are formed of 10 photoelectric sensors each, the number of dimension detection circuits may be four, which is 1/10. (3) In connection with the preceding paragraph, processing time is reduced. (4) According to the embodiment, the degree of defects to be detected can be relaxed or the viewpoint of detection can be changed depending on the purpose.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is an explanatory diagram showing the arrangement of conveyed banknotes and photoelectric sensors in one embodiment, FIG. 3 is a time chart of the operation of each photoelectric sensor, and FIG. 4 5 is a block circuit diagram showing the configuration of one embodiment, FIG.
FIG. 6 is an explanatory diagram showing the arrangement of photoelectric sensors in a conventional example when banknotes are conveyed in the longitudinal direction, and FIG. 7 is an explanatory diagram showing the arrangement of photoelectric sensors in the conventional example when banknotes are conveyed in the width direction perpendicular to the longitudinal direction. An explanatory diagram showing each is shown. Code explanation G1, G2, G3, Ga, Gb, Gc:
Photoelectric sensor group, CL: clock pulse, R: reset signal, 1, 1a to 1e: photoelectric sensor, 2A,
2B, 2C: width determination circuit, 3A, 3B, 3C: dimension detection circuit, 4: dimension abnormality determination circuit, 9: banknote,
10: Input circuit, 20: NOR circuit, 30: Counter, 40A, 40B: Upper and lower limit comparators.

Claims (1)

[Scope of Claims] 1. A method for detecting an abnormality in the dimension of a substantially rectangular paper sheet that is transported in the direction of one side, as measured in the transport direction, including: (a) in the width direction perpendicular to the transport direction; (b) an appropriate number of photoelectric sensor groups G each consisting of an appropriate number of adjacent photoelectric sensors 1 arranged linearly at approximately equal intervals over the entire width of the paper sheet; (b) each of the photoelectric sensors; Each width outputs a normal width signal indicating that the width of the paper sheet corresponding to each photoelectric sensor group G is normal based on the paper sheet presence detection signal from each photoelectric sensor 1 belonging to the group G. (c) each dimension detection circuit 3 that outputs a signal corresponding to the dimension in the transport direction based on each of the normal width signals; (d) a signal corresponding to the dimension in the transport direction based on each of the normal width signals and a predetermined A common dimensional abnormality determination circuit 4 outputs a dimensional abnormality signal based on the set value, and detects an abnormality existing in any of the dimensions measured in the conveyance direction of paper sheets corresponding to each photoelectric sensor group G. A method for detecting dimensional abnormalities in paper sheets, which is characterized by being able to detect them. 2 In the method described in claim 1,
A dimensional abnormality detection method for paper sheets, characterized in that each photoelectric sensor group G has approximately the same number of photoelectric sensors 1. 3. In the method described in claim 1 or 2, each width determination circuit 2 is an AND circuit that outputs a normal width signal only when all of the paper sheet presence detection signals are present. A method for detecting dimensional abnormalities in paper sheets. 4. In the method described in claim 1 or 2, each width determination circuit 2 is a comparison circuit that outputs a normal width signal only when the paper sheet presence detection signal is a predetermined number or more. A method for detecting dimensional abnormalities in paper sheets. 5 In the method described in any one of claims 1 to 4, each dimension detection circuit 3
A method for detecting dimensional abnormalities in paper sheets, characterized in that the counter is a counter that receives as input the normal width signal, a clock pulse, and a reset signal issued each time each paper sheet arrives. 6 In the method described in any one of claims 1 to 5, the dimensional abnormality determination circuit 4 determines whether the signal corresponding to each dimension in the conveyance direction falls within the range of the predetermined upper limit and lower limit setting values. A dimensional abnormality detection method for paper sheets, characterized in that a dimensional abnormality signal is output only when the size exceeds the limit. 7 In the method described in any one of claims 1 to 5, the dimensional abnormality determination circuit 4 determines the difference value between the maximum value and the minimum value of the signals corresponding to each dimension in the conveyance direction. A dimensional abnormality detection method for paper sheets, characterized in that a dimensional abnormality signal is output only when the dimensional abnormality exceeds a predetermined value.