JPS59634Y2 - Recording paper detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a recording paper detection device that automatically detects the presence or absence of recording paper.

For example, in a thermal recorder, it is necessary to prevent unnecessary temperature rise and wear of the recording head by detecting the presence or absence of recording paper and stopping power to the recording head and stopping the paper feed motor.

Conventionally, there are methods for detecting the presence or absence of recording paper, such as: ■ detecting the recording paper using a mechanical switch such as a microswitch, and ■ detecting the recording paper using an optical method. It has drawbacks such as being complicated and requiring expensive parts.

The present invention has been made to improve these points, and is designed to detect the presence or absence of recording paper using a simple configuration.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a configuration explanatory diagram showing an embodiment of the main parts of the recording paper detecting device of the present invention, and here, a case where the device of the present invention is applied to a thermal recorder is taken as an example.

In FIG. 1, numeral 1 is a roll of thermal recording paper, 2 is a routing head, and 3 is a rubber roller for paper feeding arranged opposite to this head.

4 and 5 are planar electrodes, one or both of which are made of an elastic material.

The recording head 2 and electrode 4 are fixed to the main body of the recorder (not shown), and the rubber roller 3 and electrode 5 are attached to the lid of the recorder (not shown).

This lid can be rotated in the direction of the arrow Y-Y', and the figure shows a state in which it has been rotated in the Y' direction, which is a closed state.

To load the recording paper 1, rotate the lid in the Y direction, separate the paper feeding rubber roller 3 and the electrode 5 from the recording head 2 and the electrode 4, and place the leading end of the recording paper 1 between the recording head 2 and the electrode. 4 side, the lid is moved in the direction of arrow Y' to press the roller 3 against the head 2 through the recording paper 1, and to press the electrode 5 against the electrode 4.

Thereafter, by energizing a paper feed motor (not shown) and the recording head 2, the recording paper 1 is sent out at a constant speed in the direction of arrow X, and the recording head 2 prints on the recording paper 1.

When the lid is closed, the electrode 5 is pressed against the electrode 4 through the recording paper 1, so that an appropriate tension is applied to the recording paper 1 by the electrodes 4 and 5, and this electrode 4.5 is applied to the recording paper 1. It also functions as a guide.

Here, (■) During normal operation (recording paper 1 is present and the lid is closed), the electrodes 4 and 5 form a capacitor with the recording paper 1 as a dielectric, and the capacitance C is C-εOεγ 5- (1) Represented by α.

Here, εO = Dielectric constant of vacuum εγ = Relative dielectric constant of recording paper 1 S = Opposing area of electrodes 4 and 5 d = Distance between electrodes 4 and 5 (thickness of recording paper 1) ◎ The lid is closed. In this state, when the recording paper 1 runs out, the electrodes 4 and 5 are short-circuited due to their elasticity.

◎ When the cover is opened to replace the recording paper 1 (including cases where the cover is opened carelessly during normal operation), the electrode 5 is connected to the electrode 4.
, and the capacitance C becomes almost zero.

If the capacitance C formed by the electrode 4°5 is detected in the state of ■~O as described above, then the above ■~
In other words, it is possible to detect the presence or absence of recording paper and the state at the time of replacing the recording paper.

Various electric circuits can be used to detect the state of the capacitance C, one example of which is shown in FIG.

In FIG. 2, IT is a terminal to which an input pulse is applied;
PD is an integral type pulse edge detection circuit, and the inverter I
It consists of an integrating circuit consisting of V, a resistor R, and a capacitor C, and a NAND cable (NG).

The capacitance formed between the electrodes 4 and 5 described in FIG. 1 is used for the capacitor C in the integrating circuit.

The MO is a retriggerable monomulti, and its input end is connected to the output end of the pulse edge detection circuit PD, and the output end of the MO is connected to the output terminal OUT.

The operation of the circuit shown in FIG. 2 will be explained as follows using the operational waveform diagram of FIG. 3.

During normal operation, the capacitance C formed by the electrodes 4 and 5 shown in FIG. 1 and expressed by equation (1) is added to the circuit in FIG. 2 as the RC time constant C.

An input pulse shown at E in FIG. 3 is applied to the input terminal IT.

The edge of this pulse input is detected by the pulse edge detection circuit PD, and the output of the NAND game 1-NG is the third
The waveform will look like waveform F in the figure.

This edge is applied to a retriggerable monomulti MO, and the output of this multi becomes <H'' (by) as shown in G in FIG. 3, and this l/H// signal is taken out from the output terminal OUT.

Next, when the recording paper 1 runs out, the electrodes 4 and 5 are short-circuited, so the edge shown at F in FIG.
l (low).

Also, even if the lid is opened to replace the recording paper 1, the capacitance C becomes almost zero, so no edge is detected in the same way, and the output of the retriggerable monomulti MO is III, /
Becomes I.

Therefore, if the above-mentioned conditions ■ to ○ are detected by the signal taken out from the output terminal OUT, and the power supply to the paper feed motor and the recording head 2 is controlled based on this detection signal, unnecessary temperature rises in the recording head can be avoided. Also, wear and tear can be prevented.

In the device of the present invention having such a configuration, the capacitance between a pair of opposing plate electrodes is detected through the recording paper, so the presence or absence of the recording paper and the state when replacing the recording paper can be extremely monitored. It can be detected with a simple mechanism.

Another advantage is that the state of the capacitance can be detected using a relatively simple electric circuit.

In addition, although the above-mentioned example illustrated the case where the device of the present invention is applied to a thermal recorder, the present invention is not limited to a thermal recorder, and can also be applied to a recorder using ink writing recording paper or discharge recording paper. equipment can be applied.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the configuration of the main parts of an embodiment of the device of the present invention, Fig. 2 is a connection diagram of an example of an electric circuit used in the device shown in Fig. 1, and Fig. 3 explains the operation of the circuit shown in Fig. 2. FIG. 1... Recording paper, 4, 5... Planar electrode.

Claims (2)

[Scope of utility model registration request] (1) A first planar electrode fixed to the main body of the recording instrument and provided in the middle of the moving recording paper, which is attached to the lid of the recording instrument and rotatably movable with respect to the first planar electrode. and a second planar electrode that is pressed into contact with the first planar electrode through the recording paper when the lid of the recording instrument is closed, and the recording device is equipped with a second planar electrode that is pressed into contact with the first planar electrode through the recording paper, and the recording device is controlled by the capacitance between the pair of planar electrodes. A recording paper detection device characterized by detecting the presence or absence of paper. (2) the state of the capacitance is determined by an integral edge detection circuit in which a rectangular wave input is applied and the capacitance between the pair of planar electrodes is applied to a capacitor of the integral circuit;
A recording paper detecting device according to claim 1, wherein detection is performed by a retriggerable monomulticircuit provided with the output of the integral edge detecting circuit.