JPH047242A - Double detecting method and circuit thereof for measured object of paper or the like - Google Patents

Abstract

PURPOSE:To set an optimum discrimination level relating to a measured object by adjusting an output from a light receiver, related to a reference measured object, to a predetermined level in a condition that a quantity of light of a light projector is fixed thereafter by detecting the measured object. CONSTITUTION:First, paper P, which serves as a reference, is arranged between a light projector 1 and a light receiver 2. An amplifier 4 performs I/V conversion to generate an output to an MPU6 by projecting light of fixed quantity by the light projector 1 and allowing a current, in proportion to a quantity of light received through the paper P, to flow by the light receiver 2. An in-flow of the current is generated in the amplifier 4 by outputting a signal to a light receiving current variable amplifier 5 for setting the most efficient range of the amplifier 4 by the MPU6 based on its voltage value. A discrimination level is calculated by calculating an output from the amplifier 4, and an arithmetic result of the level is stored in a memory in the MPU6. Thereafter, a voltage value of an objective measured object is fetched, and when the value is different from the discrimination level, the discrimination result is output by driving an output relay circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for non-contact detecting overlap of paper or a transparent body (an object that transmits thin light), and an overlap detection circuit thereof.

[Prior Art] Conventionally, for example, in a sheet-fed printing press, paper is fed from a paper feed tray, and the paper is aligned in the front, back, left, and right directions on the feeder.
It is used to supply the printing press. In this type of sheet-fed printing press, in order to detect whether there is a single sheet of paper on the feeder without contact, an emitter and a light receiver are installed on the feeder, and the amount of light when the paper passes is electrically converted. Then, this output level is compared with a preset discrimination level, and the equipment is stopped according to the result.

In the case of paper, the preset judgment level needs to be changed depending on the unevenness, thickness, etc. of the paper. Conventionally, the following method has been used.

(b) A method of varying the light intensity of a projector and adding a certain estimated amount to the electrically converted amount of light transmitted through one sheet of paper to determine the judgment level.

(b) A sheet of paper is emitted and placed between the light receivers, the amount of light received in this state is converted to an amount of electricity, the amount of emitted light is changed to a level where the output is a straight line, and the amount of electricity is memorized, Next 2
A showing method in which a sheet of paper is emitted, placed between light receivers, and the amount of received light is converted into an amount of electricity, which is set as the discrimination level at the midpoint of the amount of electricity.

[Problem to be Solved by the Invention] However, in the method (a) above, due to the relationship between the amount of light emitted and the light-receiving element, when the amount of light received is large, the estimation margin is added to the non-linear part of the amplification amplifier, and when adding an estimation margin, there is only a small margin. cannot be added. For this reason, there is a problem that malfunctions may occur due to paper gaps or floating.Also, when the amount of light received is small, the gain of the amplifier is constant, so
You will soon become saturated. For this reason, the dynamic range of the light-receiving element cannot be directly reproduced by an amplifier, making it difficult to use it over a wide range.

On the other hand, in the method (b) above, by changing the amount of light emitted and using the linear part of the amplification amplifier, it is excellent when the amount of received light is small, but when the paper is thin or transparent The amount of light received increases, and in that case, the amount of light emitted is reduced, making it vulnerable to "gap unevenness", "disturbance light", "paper flapping", etc.

The purpose of this invention is to solve the above-mentioned problems by setting an optimal discrimination level for the object to be measured without causing malfunctions due to "unevenness" or "floating" disturbance light of the object to be measured. It is an object of the present invention to provide a method for detecting duplication of paper or transparent objects and a duplication detection circuit thereof, which can be performed extremely easily.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the first invention of the present application places a reference object to be measured between a light emitter and a light receiver, and measures the reference object while keeping the light intensity of the light emitter constant. The gist of this method is to adjust the output from a light receiver related to the object to be measured to a predetermined level, and then detect the object to be measured.

Moreover, the duplication detection circuit of the second invention is illuminated by a light emitter,
a light receiver that receives light transmitted through or reflected by the object to be measured;
a light receiver output variable circuit connected to the light receiver and varying the output from the light receiver; a converter connected to the light receiver and the light receiver output variable circuit to convert the output from the light receiver;
The gist thereof is to include a control circuit for driving the light receiver output variable circuit.

[Function] According to the first invention, when there is one reference measurement object, for example, the output from the light receiver is adjusted to a predetermined level convenient for measurement, and then two measurement objects are placed. Since the outputs from the light receivers are sometimes different, it is possible to detect that the objects to be measured are overlapping, and thereby the optimum discrimination level can be selected.

Alternatively, when there are two reference objects, for example, the output from the receiver is adjusted to a predetermined level convenient for measurement, and then when one object is placed, the output from the receiver will be different. It is possible to detect that there is only one object to be measured, and thereby the optimum discrimination level can be selected.

In the second aspect of the invention, a light receiver that receives light via a reference measurement object converts an output corresponding to the amount of light received via a converter. Further, the control circuit drives the photoreceiver output variable circuit to vary the output from the photoreceiver in order to set the conversion of the converter to a range that allows suitable conversion. As a result, the converter converts the output of the optical receiver at its preferred level.

[Example] Hereinafter, an example embodying the present invention will be described in detail with reference to FIG.

As shown in FIG. 1, a light projector 1 and a light receiver 2 are arranged facing each other with a predetermined distance therebetween. The light projector 1 projects a constant amount of light by a constant current circuit 3 driven by a microprocessor (hereinafter referred to as MPU) 6, which will be described later.

The photoreceiver 2 is composed of a photodiode, and is connected to the input terminal of an amplification amplifier 4 as a converter so as to be reverse biased. The amplification amplifier 4 is an I/V converter, and its output side is connected to the MPU 6. A light reception current variable amplifier 5 as a light receiver output variable circuit is connected to the MPU 6 as a control circuit. The light receiving current variable amplifier 5 is a V/I converter, and the amplification amplifier 4
The entire circuit constitutes a current summation circuit.

An output relay circuit 7 is connected to the MPU 6, and the MPU
The determination result of step 6 is output.

Now, the operation of the electric circuit configured as described above will be explained.

First, the floodlight 1. A paper P serving as a reference is placed between the light receivers 2. Emitter 1 emits light with a constant amount of light, and receiver 2 emits paper P.
Flows a current proportional to the amount of light received through the device. The amplification amplifier 4 performs I/V conversion and outputs it to the MPU 6. Based on the voltage value outputted at that time, the MPU 6 outputs a signal to the variable light receiving current amplifier 5 to drive it in order to set the amplifier 4 to the most efficient range, and the variable light receiving current amplifier 5 operates based on the signal. current to the amplification amplifier 4.

Then, the MPU 6 takes in the output from the amplifier 4 after the current from the variable light receiving current amplifier 5 flows into it, calculates the output, calculates the discrimination level, and stores the calculation result in the memory inside the MPU 6. do. From now on MP
U6 is driven so that the same current as when measuring the reference paper flows from the light receiving current variable amplifier 5 to the amplification amplifier 4.

After this, the object to be measured is placed on the projector 1.
When placed between the light receivers 2, the MPU 4 is an amplification amplifier 4.
If the voltage value is different from the discrimination level stored in the memory, the output relay circuit 7 is driven to output the discrimination result, and if it is the same as the discrimination level, it becomes the reference. The output relay circuit 7 is not driven.

Therefore, when one sheet of paper is used as the reference object to be measured, 1
Since the discrimination level for one sheet of paper is set, when two sheets of paper are placed between the emitter 1 and the receiver 2, the voltage value from the amplifier 4 is different from the discrimination level, so the MPU 6 outputs the output relay circuit 7. to drive.

Furthermore, when two sheets of paper are used as reference objects to be measured, the discrimination level for the two sheets of paper is set, so when one sheet of paper is placed between the emitter L and the receiver 2, the amplification amplifier 4 Since the voltage value is different from the discrimination level, the MPU 6 drives the output relay circuit 7.

In this embodiment, the setting is such that the amplification is performed in the efficient part of the amplifier 6, that is, in the linear part of the amplification factor.
etc., it can be accurately determined. Further, even when the amount of received light is small, the amplifier 4 does not become saturated immediately, and can be used over a wide range.

Variations in the measured object that occur when the light intensity of the projector is small (
Malfunctions are less likely to occur due to skimming (skimming), flapping, and ambient light.

Further, in the above embodiment, even if the light receiver is changed, the same circuit can be used, and the dynamic range of the light receiver itself or an inexpensive amplifier can be used.In other words, the dynamic range of the light receiving element can be reproduced as is with the amplifier. Can be used over a wide range. Furthermore, since the amount of light from the projector is constant, it has the advantage of being resistant to disturbance light.

In the above embodiment, the photodiode constituting the light receiver 2 is connected so as to have a reverse bias, but it may be connected so as to have a forward bias. In this case, the output of the amplification amplifier 4 becomes a negative potential.

Note that this invention is not limited to the above-mentioned embodiments, and the object to be measured may be a transparent body, and the light receiver may be placed on the same side as the projector to receive the light reflected from the transparent body. It is also possible to make arbitrary changes without departing from the spirit of the above.

[Effects of the Invention] As described in detail above, the present invention does not change the amount of light emitted by a conventional projector, but instead sets it so that the conversion is performed in the efficient part of the converter, that is, the linear part of the conversion rate. Therefore, it is possible to accurately discriminate against paper "skimming", "lifting", "disturbing light", "paper flapping", etc. Furthermore, even when the amount of light received is small, the converter does not become saturated immediately, and can be used over a wide range. Malfunctions are less likely to occur due to fluctuations in the object to be measured (skimming) and disturbance light that occur when the light intensity of the projector is small.

In addition, this invention allows the same circuit to be used even when the light receiver is changed, and the dynamic range of the light receiver itself can be handled with an inexpensive converter.In other words, the dynamic range of the light receiving element can be reproduced as is with the converter. , can be used over a wide range. Furthermore, since the amount of light from the projector is constant, it has an excellent effect of being resistant to external light.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an embodiment embodying the present invention: 1... Emitter, 2... Light receiver, 3... Constant current circuit, 4... As a converter. Amplifying amplifier, 5... A variable light receiving current amplifier as a light receiver output variable circuit, 6... A microprocessor as a control circuit. Figure 1

Claims (1)

[Claims] 1. A reference object to be measured is placed between a light emitter and a light receiver, and the output from the light receiver related to the reference object is adjusted to a predetermined level while the light intensity of the light emitter is kept constant. , and then detecting the object to be measured. 2. A light receiver that receives the light emitted from the light emitter and transmitted or reflected by the object to be measured; a light receiver output variable circuit connected to the light receiver and that varies the output from the light receiver; and the light receiver. and a converter connected to a light receiver output variable circuit and converting the output from the light receiver, and a control circuit that drives the light receiver output variable circuit. detection circuit.