JPS6057625B2 - Paper sheet detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper sheet detection device that detects the presence or absence of defects (holes, tears, folds, etc.) at the edges of paper sheets, such as tickets and printed matter.

Conventionally, the following devices have been used to detect whether paper sheets have defects such as holes, tears, folds, etc.

That is, as shown in FIG. 6, for paper sheets P being conveyed in the direction of the arrow, the light receivers 9, .
92, . ,
90, .
, 90, . . . 99, and if a bright signal is obtained from the light receivers 9, , 92, . . . 9, a defect in the paper sheet P is detected. It is determined that the

In the case of this conventional device, the output of the detector changes also when the paper sheet being conveyed moves in a direction perpendicular to the conveyance direction, or due to a change in the figure printed on the paper sheet. Therefore, a complex circuit is required to determine whether a change in the output from the detector is due to a detected defect or other conditions such as those mentioned above, and this determination requires a This method has the disadvantage that detection is extremely uncertain because it depends on the condition of the leaf (for example, soiling or deterioration of the entire paper sheet). In view of the above circumstances, it is an object of the present invention to provide a paper sheet detection device that can reliably detect the presence or absence of defects at the edges of paper sheets.

The present invention will be described below with reference to illustrated embodiments. Paper sheets 1 are conveyed along a conveyance path 2 in the direction of the arrow.

This conveyance path 2 is composed of four sets of belts 3, 4, 5, and 6, and each belt 3, 4, 5, and 6 consists of two belts, upper and lower, which grip and convey paper sheets 1. It's becoming like that. Here, two types of paper sheets 1 are handled, the maximum length is 10, the minimum length is 1, and one end has a tear D as shown (FIG. 1). A diffusion plate 16 is installed near the top surface of the transportation path 2 in parallel with the transportation path 2, and a slit 7 is installed parallel to the diffusion plate 16 near the bottom surface of the transportation path 2. The diffuser plate 16 is made of, for example, opal glass and diffuses the incident light.
is for blocking disturbance light. On the other hand, the light source 8a,
8b1 light receivers 9a and 9b are installed facing each other. However, the optical axes of the light sources 8a and 8b are directed toward the front in the transport direction of the transport path 2, and the configuration is such that indirect light from the light sources 8a and 8b enters the diffuser plate 16. Light receiver 9a, 9
b is arranged at a position where both ends of the two types of paper sheets 1 can be detected, and has a field of view greater than the difference in length between the two types of paper sheets 1 (12-11=d). The light receivers 9a and 9b are amplifiers 10
The amplifier 10 is connected to integrators 11a, 11b, and the integrators 11a, 11b are connected to comparators 12a, 12b. The integration time of integrators 11a and 11b is controlled by gate signals A, B, and C. The gate signal B is transmitted to the front end of the paper sheet 1 being conveyed to the light receiver 9a.
, 9b, the integrators 11a and 11b are activated when the gate signals A and C are detected by the paper sheets 1 and 9b, respectively.
The integrators 11a and 11b are activated when the central and rear end portions of the light beams are detected by the light receivers 9a and 9b. The gate signals A, B, and C are predetermined based on the conveyance speed of the conveyance path 2. Comparators 12a and 12b output output signals G and H when input signals exceeding predetermined comparison levels E and Fl are received, respectively.
, H is controlled by a timing signal D. Next, the operation of the above configuration will be explained. First, a case where the paper sheet 1 does not have a tear D will be explained with reference to FIG. 4. The paper sheet 1 is conveyed along the conveyance path 2 in the direction of the arrow while being held by the belts 3, 4, 5, and 6! Ru.

When the front end of the paper sheet 1 faces the slit 7, a gate signal B is applied to the integrator 11a. Since the light receivers 9a and 9b receive the transmitted light of the paper sheet 1, they output a dark signal (a signal at a level shown as 0V in FIG. 4).
Therefore, since the gate signal B is applied, the integrator 11a performs negative integration. The output level of this integrator 11a is maintained until the next gate signal is applied. Then, when the center of the sheet 1 faces the slit 7, the gate signal A is applied to the integrators 11a, 11.
b. Therefore, the integrators 11a and 11b perform positive integration. At this time, the output level of the integrator 11a returns to 0V, while the output level of the integrator 11b becomes a value exceeding the illustrated comparison level. Each level is maintained until the next gate signal is applied. Next, when the trailing end of the paper sheet 1 faces the slit 7, the gate signal C is applied to the integrator 11b, and therefore integration is performed on the negative side, and the output level of the integrator 11b returns to 0V. Timing signal D is then applied to comparators 12a and 12b for comparison, but integrators 11a and 11b
At this time, the output levels of both are O■, which is less than or equal to the comparison levels E and F, so the signals G and H are not output. Therefore, it is detected that the paper sheet 1 has no defects. Next, a case where one end of the paper sheet 1 has a tear (defect) D as shown in FIG. 1 will be explained with reference to FIG. 5. When the paper sheet 1 is transported by the transport path 2 and the front end of the paper sheet 1 faces the sulin 7, the gate signal B is applied to the integrator 11a in the same manner as described above.

Therefore, integration is performed from the initial level of 0V to the negative side in the integrator 11a. When the application of gate signal B ends, the output level of integrator 11a is maintained.
The paper sheet 1 is further conveyed, and the center part is slit 7.
When facing the gate signal A, the gate signal A is applied to the integrators 11a and 11b. Therefore, the integrator 11a performs integration from the previous level to the positive side, but since the paper sheet 1 has a defect D,
Since the output of the photodetector 9a becomes a bright signal (higher level than the dark signal described above), the integrator 11a as shown in FIG.
The output level becomes +V, which exceeds the comparison level E. And this level is maintained. On the other hand, since the gate signal A is also applied to the integrator 11b, positive integration is performed and this integrated value is temporarily held. Next, when the rear end of the paper sheet 1 faces the slit 7, the gate signal C is applied to the integrator 11b, and negative integration is performed. At this time,
The light receiver 9b is connected to the amplifier 10 in parallel with the light receiver 9a. Therefore, the integration on the negative side of the integrator 11b is performed up to the level of the bright signal, and is held at this level +V. When the timing signal is applied to the comparators 12a and 12b, both comparators 12a and 12b have inputs that exceed the comparison levels E and F, so comparison outputs G and H are output, and the paper sheet 1 is It is detected that defect D has occurred. Note that since the photoreceivers 9a and 9b are connected in parallel to the amplifier 10, if either photoreceiver 9a or 9b detects a defect, it is determined that a defect has been detected, but each receives an independent detection signal. The position of the detected defect may also be detected at the same time.

Further, the diffuser plate 6 sufficiently diffuses the indirect light from the light sources 8a and 8b to evenly and uniformly illuminate the surface of the paper sheet 1,
It functions to ensure reliable detection.

As detailed above, the present invention has the following effects.

lThe detection target is divided into predetermined areas, and the output of photoelectric conversion of transmitted light (reflected light may also be used) for each area is integrated, and defects are detected by comparing the integrated values. Detection can be performed reliably without being affected by misalignment of the conveyance position or changes in the shape of the paper sheet.

2. The light receiver is arranged so as to detect the edge of the paper sheet to be handled, and the field of view of the light receiver is set to be greater than or equal to the difference between the maximum and minimum length of the paper sheet, so that the paper sheet is at right angles to the conveyance direction. Even if the paper sheet moves slightly in the direction, the paper sheet is unlikely to be out of the field of view of the light receiver, so it can be detected reliably. 3 By setting multiple integration periods, a single integrator performs integration of positive and negative polarity in the preceding and succeeding integration periods, which not only simplifies the configuration, but also allows an integrator to be provided for each. Since the characteristics of the integrator are more consistent than those of the above, accurate detection can be performed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a side view of the same example, FIG. 3 is a block diagram of the same example, FIGS. 4 and 5 are timing charts of the same example, and FIG. 6 is an explanatory diagram of a conventional example. 1... Paper sheets, 2... Conveyance path, 9a,
9b... Light receiver, 11a, 11b... Integrator, 12a, 12b... Comparator, A, B, C...
...Gate signal, D...Tear (defect), E,
F... Comparison level, G, H... Detection signal, 12... Maximum length of paper sheets, 11... Minimum length of paper sheets, d... ...Difference between maximum length and minimum length.

Claims (1)

[Claims] 1 A conveyance path for conveying paper sheets, a light receiver that receives transmitted light or reflected light from the paper sheets for each predetermined area of the paper sheets, and a light receiver that integrates the output of this light receiver for a predetermined period of time. It has an integrating means for holding the paper sheet, and a comparing means for comparing the output of the integrating means with a predetermined comparison level at a predetermined timing, and the light receiver detects the end of the paper sheet in a direction perpendicular to the conveyance direction. and the light receiver has a field of view greater than the difference between the maximum length and the minimum length of the paper sheet, and the integrating means sets a plurality of integration periods in the conveyance direction of the paper sheet, A paper sheet detection device characterized in that integration characteristics in preceding and succeeding integration periods have polarity of positive and negative polarities.