JPH0587946A - Tablet detector - Google Patents

Abstract

PURPOSE:To obtain a highly reliable tablet detector free from effect by pollution of a photodetecting section and slow changes in disturbance such as temperature change in the perimeter. CONSTITUTION:This apparatus is provided with an optical coupling element 9 to detect a tablet optically, a differentiation circuit 3 to differentiate an output of the optical coupling element and a threshold level generation circuit 4. It is also provided with a comparator circuit 5 to compare an output of the threshold level generation circuit with an output of the differentiation circuit 3 and a conversion circuit 7 to convert an output of the comparator circuit into a pulse having a specified time width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tablet detecting device for detecting a falling tablet.

[0002]

2. Description of the Related Art Generally, a tablet feeder (hereinafter referred to as a tablet case) which discharges tablets one by one in a tablet packaging machine has been installed in order to confirm the discharge of tablets.
As disclosed in Japanese Patent No. 9295, a device for detecting a tablet is provided by blocking the discharged tablet from passing through an optical path from a light emitting element to a light receiving element to block light.

However, since the above-mentioned configuration is to detect by utilizing the voltage change due to the change in the amount of received light depending on the presence or absence of light shielding of the tablet, fine powder of the tablet or dust in the air adheres to the light emitting surface or the light receiving surface. Then, there is a problem that false detection is likely to occur.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 61-99882, the output of the optical coupling element is compared with the reference voltage, and the reference voltage is changed according to the output voltage of the element. Then, the thing which prevents false detection was proposed.

[0005]

However, according to the above construction, it is necessary to provide a means for varying the reference voltage in accordance with the output voltage of the optical coupling element, and it is possible to deal with the slow variation of the disturbance such as the ambient temperature variation. On the other hand, there is a case where the reference voltage is delayed and cannot follow, and there is a problem that even if there is a tablet detection output, the output of the comparator does not change and the tablet cannot be detected.

The present invention has been made in view of the above circumstances, and provides a highly reliable tablet detecting apparatus which is not affected by a slow fluctuation of disturbance such as dirt on the photodetector or temperature change. With the goal.

[0007]

SUMMARY OF THE INVENTION The present invention provides an optical coupling element for optically detecting a tablet, a differentiating circuit for differentiating the output of the optical coupling element, a threshold level generating circuit, and a threshold level generating circuit. A comparison circuit for comparing the output with the output of the differentiating circuit and a conversion circuit for converting the output of the comparison circuit into a pulse having a predetermined time width are provided.

[0008]

According to the tablet detecting apparatus of the present invention having the above-mentioned structure, the DC output of the photocoupling element is cut by the differentiating circuit, and only the pulse waveform output when the tablet passes through the photocoupling element is used to increase the pulse height. If it is above a certain level, it can be judged that the tablet has passed and the output of the comparison circuit can be output and it is not affected by the slow fluctuations of disturbance such as dirt on the optical coupling element and temperature change. Can be improved. Also, since the output of the threshold level generation circuit is input to the comparison circuit, it is possible to input it to the comparison circuit with the output waveform of the optical coupling element and the output waveform of the differentiating circuit adjusted, which improves the reliability of tablet detection. Can be further improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a tablet supply device 6 (hereinafter referred to as a tablet case).

The tablet case 6 is formed in a vertically elongated columnar shape (length 300 mm), and has a cylindrical (diameter 46 mm) and transparent tablet case 1 for accommodating tablets at the top.
2, a prismatic mechanism 13 is detachably formed at the bottom.

The mechanism portion 13 has a groove 60 for vertically aligning a plurality of tablets at one side portion, a guide surface 61 inclined downwardly toward the groove 60, and a tablet passage on the outer periphery. An aligning member 59 having a circularly-arranged aligning member 62 formed on the guide surface 61, and a semicircular disk-shaped bearing member 98 fixed to the case to support a drive shaft 99 of the aligning member. A disk-shaped fixing plate 66 having a notch 63 for dropping tablets on a part of the outer periphery thereof, and a partition plate 65 mounted on a slit 64 formed in the middle of the groove 60, and a support having a rectangular column shape. A base 67, a connecting frame 100 for connecting the support base and the tablet case 12, and the alignment body 59 mounted on the support base 67, with the drive shaft 99 provided at the center of the alignment body serving as a fulcrum for the groove. Position where the partition plate 65 is interposed in 60 (position shown in FIG. 2 Swinging mechanism for swinging into a position without intervention and (not shown), (not shown) this is built into the support base 67 to swing mechanism to drive the gear reducer
And a drive device 70 including a DC motor 69.

Reference numeral 85 denotes a detection body which is connected to a tablet discharge passage 86 provided on the support base 67 and is detachably mounted on the upper surface of the support base 67. The structure is such that the light receiving elements 89 face each other, and the tablet passes through the recess 87 to block light, thereby generating a signal.

Then, the tablet case 12 and the support base 67 are connected to each other through the connecting frame 100, so that the tongue piece 105 is formed.
Is inserted into the recess 87 of the detection body 85 so as to cover the exposed portions of the light emitting element 88 and the light receiving element 89 of the detection body 85.

Therefore, when the tablet case 12 is inserted into the connecting frame 100 fixed to the supporting base 67, the recess 87 of the detecting body 85 also mounted on the supporting base 67 and the four sides of the connecting frame 100. The notch 63 of the fixed plate 66 is adapted to coincide with the discharge passage 86 only by inserting it into the protruding portion 95 that is protruded.

The tablet case 6 constructed in this way
When a tablet take-out signal is input from the controller of the tablet packing machine (not shown), the DC motor 69 that constitutes the drive device 70 is rotated, and the swinging mechanism converts the rotary motion into the swinging motion. This swinging motion is transmitted to the alignment body 59, and the alignment body 59 is driven by the drive shaft 9 of the alignment body as described above.
The position where the partition plate 65 is interposed in the groove 60 with the fulcrum 9 (FIG. 2).
Rocking in the horizontal direction between a position (shown in Fig. 2) and a position without interposition.

The tablets stored in the tablet case 12 enter the groove 60 by the guide surface 61, but when the aligning body 59 is at the position shown in FIG. At rest.

After that, when the alignment body 59 swings, the partition plate 65 disappears in the groove 60, and the tablet at the bottom stopped on the partition plate 65 drops onto the fixed plate 66. Then,
The aligning body 59 again starts to swing toward the position shown in FIG. 2, and one tablet dropped onto the fixing plate 66 is returned to the groove 60 below the partition plate 65, and the notch 63 of the fixing plate 66 is discharged. Aisle 86
Is discharged through.

At this time, since the falling tablets pass through the recess 87 of the detector 85, a signal that one tablet has been ejected from the tablet case 6 is detected, and this signal is the control device of the tablet packing machine. Sent to.

FIG. 1 shows a tablet detection circuit, which is an optical coupling detection circuit 1 including a light emitting element 88 and a light receiving element 89 for optically detecting a drop of a tablet, a reference voltage generating circuit 2, and the optical coupling detection circuit 1. , A threshold level generating circuit 4, a comparing circuit 5 for comparing the output of the threshold level generating circuit with the output of the differentiating circuit 3, and the output of the comparing circuit for a predetermined time. It is composed of a conversion circuit 7 for converting it into a pulse having a width and a transistor 8 for inverting the output level of this conversion circuit.

The optical coupling detection circuit 1 includes two light emitting elements 88 connected in series and three light receiving elements 89 connected in series.
And a variable resistor 14 connected in series with the light receiving element 89, a resistor 10 connected in series with the light receiving element 89, and a variable resistor 14 from the light emitting element 88 to the light receiving element 89. When the optical path to reach is not shielded, an L level potential appears at point A, and when the optical path from the light emitting element 88 to the light receiving element 89 is shielded from the tablet, the potential at H level is applied to point A. Appears. (Refer to the waveform at point A in FIG. 1) The reference voltage generating circuit 2 includes two resistors 1 connected to a power source.
5, 16 and a comparator 17 which inputs the output between the resistors 15 and 16 to the + terminal and feeds back the output to the-terminal to generate a reference voltage.

The differentiating circuit 3 is composed of a resistor 18 and a capacitor 19 which are connected in series between the output side of the optical coupling detecting circuit 1 and the output side of the reference voltage generating circuit 2. The output is cut, and as shown by the waveform at point B in FIG. 1, the output of the waveform that passes only the pulse when the tablet is shielded from light is obtained.

The threshold level generating circuit 4 includes a variable resistor 20 and a resistor 21 connected in series to the output side of the reference voltage generating circuit 2, and a diode 22 and a resistor 23 connected in series to the feedback line of the output of the comparison circuit 5. And a hysteresis is provided by the diode 22 and the resistor 23 so that the voltage level at the point C becomes high to prevent the comparison circuit 5 from returning to the original state.

The output of the threshold level generating circuit 4 is input to the + terminal of the comparing circuit 5, and the output of the differentiating circuit 3 is input to the-terminal of the comparing circuit 5 for comparison. That is, the comparison circuit 5 compares only the heights of the pulse waveforms whose direct current output has been cut by the differentiating circuit 3, and outputs an L level signal when the heights are above a certain level (for example, above 2V). To do. As a result, the optical coupling element 9 is not affected by disturbance fluctuations that are slower than the tablet passage signal, such as contamination of the optical coupling element 9, a decrease in light output, and a change in the saturation voltage of the optical coupling element 9 due to ambient temperature fluctuations. The output signal of the comparison circuit 5 can be output.

The conversion circuit 7 inputs a parallel circuit of the resistor 24 and the diode 25 connected to the output side of the comparison circuit 5 and the output of this parallel circuit to the + terminal and outputs the output of the reference voltage generation circuit 2 to the − terminal. It is composed of a comparator 26 which is connected to the comparator 26, a capacitor 27 which is connected in series with a parallel circuit of the resistor 24 and a diode 25, and a capacitor 28 which is connected to an auxiliary terminal of the comparator 26. The resistor 24 and the diode 25 instantaneously discharge the voltage of the capacitor 28 when a tablet is detected, and the potential at the point D maintains the L level for a certain period of time even after the tablet has passed. That is, the output of the comparison circuit 5 is charged in the capacitor 28 through the resistor 24 having a high resistance, and the potential at the point D is held at the L level until the capacitor voltage reaches the reference voltage.

The output of the conversion circuit 7 is inverted to H level by the transistor 8 and taken out as a tablet detection signal.

Further, 29 is a resistor 30, 3 connected in series.
This is a dirt amount setting circuit consisting of 1.

Reference numeral 32 denotes a dirt detection circuit, which includes a resistor 33 and a capacitor 34 (low frequency pass circuit) connected in series.
The comparator 35 having the output of the midpoint input to the-terminal and the output of the midpoint of the dirt amount setting circuit 29 input to the + terminal
And a resistor 36 connected from the output side of the comparator 35 to the feedback path of the + terminal, and a diode 37 connected to the output side of the comparator 25.

Then, the filter circuit consisting of the resistor 33 and the capacitor 34 takes out an output in which a rapid voltage change at the time of passing the tablet is cut out, and a dirt amount setting circuit 29.
A predetermined voltage level that is considered to be dirty is set by the resistors 30 and 31, and the amount of dirt is detected by comparing these outputs with the comparator 35. That is, normally, when the tablet does not pass, the output of the filter circuit is high, and the voltage level of the + terminal is set higher by the feedback resistor 36 of the comparator 35, so the output of the comparator 35 is at the H level. ..
Then, if the optical coupling element 9 becomes dirty, the output level of the filter circuit becomes low and the feedback resistor 36 does not feed back the signal. 35
Is output from. As a result, the L-level signal of the comparator 35 becomes the H-level signal by the comparator 26 and the transistor 8, whereby the dirt of the optical coupling element 9 can be detected, and this signal can be used as a warning lamp or an alarm device. The connection improves the maintenance of the tablet feeder.

38, 39 and 40 are capacitors, 41
Is a resistor and 42 is a terminal plate.

[0031]

As described above, according to the present invention, the DC output of the photocoupling element is cut by the differentiating circuit, and only the pulse waveform generated when the tablet passes through the photocoupling element is used to increase the pulse height. If it is above a certain level, it can be judged that the tablet has passed and the output of the comparison circuit can be output and it is not affected by the slow fluctuations of disturbance such as dirt on the optical coupling element and temperature change. Can be improved. Also, since the output of the threshold level generation circuit is input to the comparison circuit, it is possible to input it to the comparison circuit with the output waveform of the optical coupling element and the output waveform of the differentiating circuit adjusted, which improves the reliability of tablet detection. Can be further improved.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a tablet detection device.

FIG. 2 is a perspective view of a tablet case.

[Explanation of symbols]

 3 Differentiation circuit 4 Threshold level generation circuit 5 Comparison circuit 7 Conversion circuit 9 Optical coupling element

Claims (1)

[Claims] 1. An optical coupling element for optically detecting a tablet,
A differentiating circuit for differentiating the output of the optical coupling element, a threshold level generating circuit, a comparing circuit for comparing the output of the threshold level generating circuit with the output of the differentiating circuit, and the output of the comparing circuit for a predetermined time width. And a conversion circuit for converting the pulse into a pulse.