JPH01226539A - Sensitivity correcting equipment for label sensor - Google Patents

Abstract

PURPOSE:To enable adjustment so that the voltage for the detecting signal, which is put in the label detecting part, can maintain an appropriate detecting level even when there are differences in the characteristics of a photo-sensor, by providing a voltage adjusting main, which can alternate the output voltage, at the output port of the photo-sensor. CONSTITUTION:An initial correcting signal is put out from correcting signal output ports 151-153 to transistors Tr1-Tr2, and all the voltage adjusting circuits 141-143 are closed. Then the combined resistance for a sensitivity correcting equipment 14 including a resistor 11 becomes minimum, and the detecting signal to be put out becomes a minimum value. For example, if resistors R1, R2, R3, which are connected in parallel, have been set at 1OMEGA, 2OMEGA, 3OMEGA, respectively, depending on the combination, seven types of combined resistances can be obtained. Thus, the voltage of the detecting signal can be corrected in seven steps. Therefore, by providing the voltage adjusting device, even when there is a difference in the characteristics of a photo-sensor due to manufacturing error on the optical element in use, the adjustment to make the input voltage for the level detecting part maintain an appropriate detecting level is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sensitivity correction device for a label sensor used in various types of electronic toll scales with label printers. etc.

The presence or absence of the label paper, the label position, etc. are detected based on the output signal of a label sensor using a photoelectric conversion element or the like.

An example of such a conventional label sensor 1 will be explained based on FIG. 3. First, as a light emitting section and a light receiving section, a light emitting diode 2 and a phototransistor 3 are arranged facing each other with a gap therebetween, forming a photosensor 4. next,
The label is prepared as a label paper (not shown) in which the label is attached to a long mount, and a label conveyance path (not shown) is prepared so that the label paper passes between the optical elements of the photosensor 4. ) is formed. On the other hand, an A/D converter 5 functioning as an output voltage detecting means and a detector 6 are connected to constitute a label detecting section 7. Therefore, the input port 8 of this label detection section 7 is connected to the photo sensor 4.
is connected to output port 9 of. Further, a resistor 11 is connected between the output port 9 and the ground 10.

In such a configuration, the operation of the label sensor 1 will be explained. First, the light emitting diode 2 is connected to the label conveyance path (
A light (
(not shown), and the light transmitted through the phototransistor 3 enters the phototransistor 3. Here, when the light is irradiating the label, the transmittance is low because the label and the mount form a nail, and the light intensity of the transmitted light is extremely weak.On the other hand, when the light is irradiating the gap between the labels, When the light is on, the light passes through only the mount, so the transmittance is high and the intensity of the transmitted light is strong. moreover.

When the mount is removed, the light is directed directly to the phototransistor 3.
Since the light is incident on the light beam, the light intensity reaches its maximum value. Therefore,
The resistance value of the phototransistor 3 changes approximately in proportion to the light intensity of the transmitted light and the direct light. At this time, the resistor 11 is set in advance based on the voltage of a power source (not shown), the resistance value of the phototransistor 3, the output voltage level necessary for the label detection section 7, and the like. The ratio of the resistance value of the resistor 11 set in this way and the resistance value of the phototransistor 3 is equal to the ratio of the voltage between the terminals of the ground 10 and the voltage between the terminals of the photosensor 4. Therefore, phototransistor 3
By changing the resistance value of the label detector 7, a detection signal of a voltage suitable for the label detector 7 can be obtained from the constant voltage of the power supply applied thereto. This detection signal is input from the input port 8 to the label detection section 7, and within the label detection section 7, the A/D converter 5 converts the analog waveform detection signal into a digital value signal. Furthermore, a detector 6 reads this digital value every moment, and the presence or absence of label paper, the label position, etc. are detected from the difference in voltage.

Problems to be Solved by the Invention A double label sensor uses elements such as a light emitting diode in its light emitting part and a phototransistor in its light receiving part. However, even these precisely manufactured elements have manufacturing errors. Therefore, since the characteristics of photosensors are not necessarily uniform, there may be differences in response characteristics between devices.On the other hand, due to temperature changes, etc., the voltage of the signal output by the photosensor may fluctuate and deviate from the detection level. Sometimes. As a result, errors occur in label detection, and the performance of the device becomes unstable.

Means to Solve the Problem In a label sensor in which a photosensor that optically detects the label paper is provided in the label conveyance path, and a label detection section that detects the label paper from the input voltage is connected to the photosensor, the output of the photosensor is A voltage adjustment means for varying the output voltage was provided at the port.

By providing a voltage mW means for varying the output voltage at the output port of the working photo sensor, label detection is possible even if the optical element used has manufacturing errors and there are differences in the characteristics of the photosensor. The voltage of the detection signal input to the section can be adjusted so as to maintain an appropriate detection level, and is stabilized approximately equally.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. Note that the same parts as those described in the conventional example described above are designated by the same reference numerals, and the description thereof will be omitted.

First, the sensitivity correction device for the label sensor 12 of this embodiment] 3
As for the configuration, for example, three voltage adjustment circuits 14, which are voltage adjustment means, are installed in the circuit from the output port 9 of the photosensor 4 to the input port 8 of the label detection section 7. , 14
2.14. is formed. This voltage adjustment circuit 141
．． 142.14. are resistors R,, R2, R, and transistors Tr1. Tr, Tr3, and the terminals are grounded. and the transistor T L”i
, T r2. Tr, are connected to the correction signal dose capos 1-151, 15□, 153 of the detector 6, respectively.

In such a configuration, the operation of the sensitivity correction device 13 of the label sensor 12 will be explained with reference to the flowchart shown in FIG. First, if it is determined that correction of the detection signal is necessary, the device is switched to a diagnostic mode (self-diagnosis mode) by operating a dip switch or the like. At this time, if there is no label paper in the label transport path, measurement will not be possible, so after preparing and confirming this, for example, by operating the ■ key, the device enters the correction start state. At this time, first, the correction signal output port 15 of the detection Wt6. The initial correction signal corresponding to 7 is output from the transistors 141 to 15 to the transistors 141 to 14. are all closed. Therefore, the combined resistance of the sensitivity correction device 13 including the resistor 11 becomes the minimum, and the output detection signal becomes the minimum value. In addition.

The correction signals to each of the transistors Tr to Tr3 described above are each 1 bit, and are performed using binary numbers of 0 and 1. Therefore, three transistors Tr□ to Tr.

The correction signal for closing is initialized by 111=7. Therefore, for example, the resistor R1 connected in parallel,
By setting R, , R, to 1Ω, 2Ω, 3Ω, etc., seven types of combined resistances can be obtained by combining them, and the voltage of the detection signal can be corrected in seven stages.

Next, the detection signal that has reached the minimum value as described above is input to the A/D converter 5, which acts as an output voltage detection means type. This A/D converter 5 will not overflow if the voltage of the signal input to it is below a certain value, so if the voltage of the detection signal is not above a certain value, the detector 6
cannot detect the presence or absence of label paper, etc. Therefore, if the detector 6 reads the input signal and the A/D converter is overflowing at that point, no further signal correction can be performed. Since it is not necessary, the correction work is completed. Furthermore, if the A/D converter 5 does not overflow, the sensitivity correction device 13 further corrects the detection signal to a level that allows label detection.
The correction signal is sequentially increased from 7 to 6 so that the combined resistance of
, 5, and so on. and,
This detection signal correction work is repeated until the A/D converter 5 overflows, at which point it ends. It is also conceivable that the correction signal drops to 0 even though the A/D converter has not overflowed. In this case, there is a high possibility that there is another cause, such as a poor contact of one of the light emitting diodes, so the detector 6 displays an error and ends the operation.

Effects of the Invention As described above, the present invention provides a voltage adjustment means for varying the output voltage at the output port of the photosensor. Even if there is a difference in the characteristics of the label detector, the voltage of the detection signal input to the label detector will be approximately equal, so there will be no difference in response characteristics between devices. Since the voltage can be adjusted to maintain an appropriate detection level, there is no error in detecting the presence or absence of label paper or the position of the label.
This has the effect of making the sensitivity of the label sensor stable and accurate.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a flowchart, and FIG. 3 is a circuit diagram of a conventional example. 4... Photo sensor, 7... Label detection section, 9...
- Output boat, 12... Label sensor, 13... Sensitivity correction device, 14... Voltage adjustment means

Claims (1)

[Claims] A label sensor in which a photosensor for optically detecting a label paper is provided in a label conveyance path, and a label detection unit for detecting the label paper from an input voltage is connected to the photosensor, the output voltage is connected to an output port of the photosensor. A sensitivity correction device for a label sensor, characterized in that a voltage adjustment means for varying the voltage is provided.