JPH0235249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge recorder, and more specifically, to a discharge recorder having a large number of discharge electrodes arranged in parallel in a direction perpendicular to the feeding direction of discharge recording paper. .

The applicant has already filed several applications for this type of multi-needle electrode discharge recorder. For example, Japanese Patent Application No. 55-65747
No. 161176) uses a counter for sequentially scanning a multi-needle electrode energization control element (thyristor) and a successive approximation type A/D converter. Start counting the A/D
A recording electrode selection method is disclosed which compares the output of the converter and the counter and supplies a coloring signal to the thyristor at the point of coincidence. According to this, it is possible to select recording electrodes at high speed only by digital processing, and it is also advantageous for multi-channeling, that is, for overwriting multiple input signals on the same time axis. In order to increase the reproducibility of waveforms by speeding up the input signal sampling time, the following points need to be kept in mind. That is,
By increasing the scanning speed of the thyristor mentioned above, the sampling time can be shortened as a result, but a voltage application time of 7 μs or more is required for stable color development of the discharge recording paper, and the thyristor still has some drawbacks. The time required for an arc is approximately 0.7-1.0 μs. Furthermore, the feeding speed of the recording paper was increased to 100 cm/s.
In the above case, the current value required to cause sufficient discharge destruction on the recording paper reaches several times that of the low speed. For this reason, it is necessary to provide a sufficiently long turn-off time for the thyristors; if this time is insufficient, all the thyristors remain conductive and recording becomes impossible.

This invention overcomes the various limitations described above, and
The object of the present invention is to provide a discharge recorder capable of recording input signals at high speed and with high precision on discharge recording paper that is fed at a speed of, for example, 200 cm per second.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

As shown in the block diagram of Fig. 1, this discharge recorder has six input amplifier units 1 to enable simultaneous recording of, for example, six channels of signals, and a corresponding one for each of the input amplifier units 1. 6 analog input pulse position conversion units 2 connected to each other, a counter unit 3 including a clock pulse oscillator and outputting an operation control signal to the units 2, and a counter unit 3 that operates in synchronization with the counter unit 3 to scan the recording electrode. a decoder unit 4 that generates trigger pulses for
a head driver unit 5 for the recording electrodes connected to the output side of the recording electrode; and an OR circuit 6 for supplying the outputs of the respective analog input pulse position conversion units 2 as a pulse train to the head driver unit 5.
The power switch unit 7 includes a power switch unit 7. The recording electrodes are indicated by reference numeral 8 in FIG.
It is assumed that 200 wires are installed in parallel at a pitch of 0.5 mm.
Although not shown, this discharge recorder is equipped with a paper feeding unit for feeding the recording paper P at a predetermined speed.

Above analog input pulse position conversion unit 2
is inputted via the count value of the counter unit 3 and the amplifier unit 1 when the recording electrodes 8 from the zero position to the maximum scale position (199) are sequentially scanned by the decoder unit 4 so that they can be energized. This is a unit that generates a pulse for supplying a recording current to the recording paper P via the recording electrode 8 when the analog input level corresponds to the analog input level.
A D converter 10, a latch circuit 11 that temporarily holds the output value of this A/D converter 10, and a counter unit 3 that outputs the output value held in the latch circuit 11.
It consists of a comparison circuit 12 which compares the count value of , and a one-shot multivibrator 13 which operates in response to the output of this comparison circuit 12 .

The counter unit 3 includes an oscillator 14 for generating clock pulses. In this case, since the output of the A/D converter 10 is a binary code signal, it is desirable that the counter that controls this is also a binary code output type counter.
Therefore, in this embodiment, the counter unit 3 consists of an 8-bit 256-base binary counter,
Also, the frequency of the clock pulse is set to 10MHz. Therefore, this counter unit 3
One counting period is 25.6 μs.

The decoder unit 4 is for forming decimal trigger pulses to sequentially scan each gate of the thyristors 15 and to enable the thyristors to conduct electricity. In this case, the counter unit 3
If you try to convert the binary output from A synchronization relationship with the pulse will no longer hold, and the recording will be inaccurate.

Therefore, in the decoder unit 4 according to the present invention, as shown in FIG. Convert into 200 trigger pulses corresponding to each of the recording electrodes 8 up to
A BCD-decimal conversion circuit 23 is provided. That is, the counters 20 to 22 are configured to count clock pulses from the oscillator 14 applied to the terminal CP via the counter unit 3, and output signals of each digit of x1, x10, and x100, respectively. The counter unit 3 is a synchronous counter, and the counting operation is temporarily stopped or reset in synchronization with the counter unit 3 by a control signal applied via a terminal S, for example.

The BCD-decimal conversion circuit 23 is composed of, for example, a BCD-decimal converter (not shown) and a logic element, and converts the single-digit signals 0, 1, 2, . . . 9 output from the BCD counter to 2 digit signal 0,
10, 20, . . . 90 and the three-digit signals 0 and 100 are combined here and converted into 200 signals from 0 to 199. Each of these signals starts from number 0 above.
It is output to the head driver unit 5 as a trigger pulse for scanning each recording electrode 8 numbered 199.

According to the decoder unit 4 configured in this manner, a clock pulse can be converted into a decimal trigger pulse at high speed, there is no synchronization problem, and accurate signal recording is possible.

Here, while referring to the timing chart in FIG. 2, convert the analog input pulse position conversion unit 2.
The operation of the counter unit 3 and the counter unit 3 will be explained. Note that in the figure, hatched or dotted areas indicate a state in which the data content remains unchanged. The A/D converter 10 is, for example, an 8-bit successive approximation type A/D converter, and is controlled by an A/D conversion command signal output when the count value is "0" in the first counting period of the counter unit 3. , converts the analog signal into an 8-bit digital signal. Note that the time required for this conversion is approximately 7.5 μs. This A/D
The converted value is supplied to the latch circuit 11, and when the count value of the counter unit reaches, for example, "240", it is read into the latch circuit 11 and held. The A/D conversion value held in the latch circuit 11 is compared with the count value of the counter unit 3 by the comparator circuit 12 in the second counting period of the counter unit 3, and at the point of coincidence, the one-shot multivibrator 13
generates a 1.0μs pulse. A/D converter 10
When the counter unit 3 enters the second counting period and the count value is "0", it performs A/D conversion again, and this A/D conversion value is held in the latch circuit 11 in the same way as above, and then the counter unit 3 performs A/D conversion again. It is compared with its count value in the third counting period of unit 3.
That is, in this analog input pulse position conversion unit 2, the A/D converted value that is A/D converted in the n-th counting period of the counter unit 3 is temporarily held in the latch circuit 11, and is held in the latch circuit 11 once in the n+1st counting period of the counter unit 3. In the comparison circuit 12, the nth
It will be compared with the count value of +1 counting period.
In this case, the counting period of counter unit 3 is
The decoder unit 4, which operates in conjunction with this, scans the recording electrode 8 with a trigger pulse during the 200 counting periods from ``0'' to ``199'', and the remaining counting period is 25.6 μs. The "56" counting period (5.6 μs) is allocated to the rest period.
During this pause period, the A/D converter 10 and the latch circuit 1
This is to compensate for the stable color development time when data is exchanged between 1 and 199th recording electrode 8 is energized.

In this embodiment, one counting time of the counter unit 3 is 0.1 μs, and within this time, the signal is transferred from the decoder unit 4 to the gate of the thyristor 15 (see FIG. 3), which is the energization control element of the head driver unit 5. Even if a trigger pulse is supplied, it is difficult to reliably fire the thyristor 15. Therefore, the analog input pulse position conversion unit 2 uses the pulse of the one-shot multivibrator 13 that is generated at the time when the A/D conversion value and the count value of the counter unit 3 match, to generate a signal for the pulse generation period of, for example, 1.0 μs. During this period, the operation of the counter unit 3 is stopped and the counted value is maintained. In synchronization with this, the decoder unit 4 also temporarily stops scanning at that point, so that the thyristor 15 has a firing time of 1.0 μs. Therefore, one counting period of the counter unit 3 is:
25.6+0.9×nμs (n: number of channels used),
When using 6 channels, the sampling period is 31 μs. The above constant is set to 0.9 μs because the pulse generation period output from the one-shot multivibrator 13 is 1.0 μs.
This is because when viewed from the counter unit 3, one counting time of 0.1 μs is included in the 1.0 μs.

Next, the above power switch unit 7 will be explained. The purpose of this unit 7 is to supply a recording current to the recording electrode 8, which has been made energized via the decoder unit 4 by the operation of the counter unit 3 described above, for a period of time to obtain stable color development, and to supply a recording current to the recording electrode 8, which can be energized via the decoder unit 4 by the operation of the counter unit 3 described above. , to give the thyristor 15 sufficient turn-off time. The time required for stable color development is related to the paper quality of the discharge recording paper, that is, the color development performance, but at present, a recording pulse application time of approximately 10 μs is required. By the way, for example, when using 6 channels, assuming that the recording positions are scattered almost evenly over the entire surface of the recording paper P, the width of the recording pulse reaches a maximum of 20+0.9×6+10=35.4 μs. (Note that 10 μs in this formula is the recording pulse application time when the 199th thyristor is selected.) In other words,
25.6 + 0.9 which is the counting period of counter unit 3
By exceeding ×6=31 μs, in this case, not only the recording current continues to flow for 35.4 μs to the recording electrode 8 that was fired first, but also the recording current continues to flow to the recording electrode 8 that is fired first in the next counting cycle. Depending on the position of the thyristor 8, the thyristor 15 cannot be extinguished. Furthermore, if each input of the 6 channels is fluctuating in this state, 1 of the counter unit 3
Six recording electrodes remain energized in each counting cycle, and there is a risk that all 200 recording electrodes 8 will become energized in 34 cycles and lose their function as a recorder.

Therefore, in the present invention, in order to prevent the above-mentioned situation from occurring, the recording electrodes 8 and the corresponding thyristors 15 are divided into four groups of, for example, 50 thyristors in chronological order, and one switching element is assigned to each group. Assigned. That is, as shown in FIG. 3, the head driver unit 5
are divided into a first group 5a to a fourth group 5d, and each of these groups 5a to 5d is connected to a coloring power supply circuit 17 via high power switching transistors 16a to 16d, respectively. Correspondingly, this power switch unit 7 includes a gate circuit 18 that distributes the pulse train supplied from the OR circuit 6 to each group based on the count value from the counter unit 3, and an output side of this gate circuit 18. The switching transistors 16a to 16 described above
d and four one-shot multivibrators 19a to 19d connected between each base.

Next, the operation of this power switch unit 7 will be explained with reference to the timing chart shown in FIG. In this figure, the shaded area shows the state in which the counter unit 3 is performing a counting operation. Pulses generated from each one-shot multivibrator 13 of the analog input pulse position conversion unit 2 described above are supplied as a pulse train to one input terminal of a gate circuit 18 via an OR circuit 6. Therefore, the gate circuit 18
The pulse train is transmitted in chronological order according to the recording electrodes 8 divided into four groups as described above based on the count value applied to the other input terminal from the counter unit 3 and the time point of the pulse input supplied from the OR circuit 6. Sort it out. Based on the signals divided in this way, the corresponding one-shot multivibrators 19a to 19d provided in each of the four groups generate a 10 μs pulse, and the corresponding switching transistor is turned on during the generation period of this pulse. become. Therefore, a thyristor 15 is connected to the recording electrode 8 at the position corresponding to the A/D converted value A/D converted by the analog input pulse position conversion unit 2 (the gate of this thyristor is connected to the thyristor 15 from the decoder unit 4).
A 1.0μs trigger pulse is applied. ) is supplied with recording current. In this embodiment, when a 1.0 μs trigger pulse is applied to one thyristor 15 and that thyristor becomes conductive, the decoder unit 4 synchronizes with the counter unit 3 as described above. Temporarily stop electrode scanning for that period and switch to other thyristors.
Malfunctions are prevented by preventing the 0.1 μs trigger pulse from being output. In this way, the head driver unit 5 is divided into groups, and the switching transistors are turned on and off independently of each other.
By turning off the thyristor, the turn-off time of the thyristor can be sufficiently long. To explain more specifically, when two channels are used, for example, when the recording electrode at the first position and the recording electrode at the 50th position belonging to the first group 5a enter the recording state, 50 recordings are made. Electrode scanning time is 5μs,
Since the firing time of the two recording electrodes is 0.9×2 μs and the remaining time of applying the recording pulse to the recording electrode at the 50th position is 9 μs, the total time is 15.8 μs. On the other hand, one counting period of counter unit 3 during two channels is 25.6×
Since 0.9×2=27.4 μs, a turn-off time of at least 11.6 μs is obtained. This 11.6 μs is the minimum value for turn-off, and this time is enough to turn off the thyristor. Furthermore, as is clear from the above explanation, the operations of the groups 5a to 5d are independent of each other, and each group can obtain the turn-off time as described above, making it possible to perform extremely stable recording operations. can.

In the above example, 200 recording electrodes were connected to 50
Although each book is divided into four groups, the present invention is not limited to this. For example, 40 books each may be divided into five groups. Further, the pulse generation time of the one shot multivibrator 19 etc. that controls the switching transistor 16 can be appropriately determined depending on the quality of the discharge recording paper used, the applied current required for discharge breakdown, etc.

As is clear from the description of the embodiments described above, according to the present invention, the thyristors, which are the energization control elements of the recording electrodes, are divided into a predetermined number of groups in chronological order as described above, and each Switching elements are connected for each group, and a gate circuit connects the printing command pulses output from the analog input pulse position conversion unit to the switching elements belonging to each group according to the count value of the counter unit at the time when the pulse is output. By distributing the switching elements to one of the elements and turning on the corresponding switching element for a certain period of time, the turn-off time of the thyristor can be made sufficiently long regardless of the operating state of the other groups. Furthermore, in the decoder unit that operates in synchronization with the counter unit, the clock pulses are counted by a BCD counter and the decimal evolution trigger pulse is obtained from the output thereof, so that the conversion speed is fast. Therefore, the synchronization relationship between the trigger pulse and the print command pulse is accurately maintained. Therefore, in addition to stable recording operation, faster and more accurate recording is realized without being restricted by the turn-off time of the thyristor.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a discharge recorder according to the present invention, FIG. 2 is a timing chart for explaining its operation, and FIG. 3 is a block diagram showing a head driver unit and a power switch unit. 4 is a timing chart regarding the block diagram of FIG. 3, and FIG. 5 is a block diagram of the decoder unit. In the figure, 1 is an input amplifier unit, 2 is an analog input pulse position conversion unit, 3 is a counter unit, 4 is a decoder unit, 5 is a head driver unit, 7 is a power switch unit, 8 is a recording electrode, and 10 is an A/D Converter, 11 is a latch circuit, 12 is a comparison circuit, 13 and 19 are one-shot multivibrators, 14 is a clock pulse oscillator, 15 is a thyristor, 18 is a gate circuit, 2
0, 21, 22 are BCD counters, 23 is BCD-
This is a decimal conversion circuit.

Claims (1)

[Claims] 1. A discharge recorder that is fed continuously or intermittently, and includes a large number of recording electrodes arranged in parallel along a direction perpendicular to the paper feeding direction, and a thyristor connected to each of the recording electrodes. a head driver unit including;
an oscillator that generates clock pulses of a predetermined frequency; a counter unit that repeatedly counts the clock pulses from the oscillator at a constant counting cycle; and a decoder that devolves the clock pulses from the oscillator into 10 and sequentially supplies trigger pulses to each of the thyristors. converting an analog input signal into a digital signal in synchronization with the counting operation of the counter unit, and comparing the A/D conversion value with the count value of the counter unit in each counting period,
A discharge recorder comprising: an analog input pulse position conversion unit that outputs a print command pulse at the time of coincidence; and a power switch unit including a switching element that controls on/off the application of a recording voltage to the head driver unit according to the print command pulse. In this system, the thyristor groups of the head driver unit are divided into a predetermined number of groups in chronological order, the switching element is connected to each group, and the printing command pulse output from the analog input pulse position conversion unit is and a gate circuit that allocates the switching element to one of the switching elements belonging to each group according to the count value of the counter unit at the time when the pulse is outputted, and turns on the corresponding switching element for a certain period of time, and the counter unit outputs a binary code. The decoder unit operates in synchronization with the counter unit and counts clock pulses from the oscillator.
BCD counter that converts to BCD code and the BCD
A discharge recorder comprising: a BCD-to-decimal conversion circuit that forms a trigger pulse for energizing the thyristor based on a count output from a counter.