JPS601196B2 - Electrostatic recording device using multi-stylus head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic recording device using a multi-stylus head used in a facsimile machine, printer/plotter, etc., and more specifically relates to a recording pulse voltage applied to a needle electrode and a control electrode and control The present invention relates to an electrostatic recording device having a novel configuration for applying a pulse voltage.

FIG. 1 is a perspective view of a multi-stylus head currently in use, showing a base 2, a needle electrode row 3, a control electrode row 4, a connector 5 provided with a lead-out terminal 51 for each needle electrode, and a connector 5 for each control electrode. It consists of a connector 6 equipped with a pull-out terminal 61, and currently has a total number of 2 that can record the full width of B4 size at a resolution of 8/Yanagi.
A multi-stylus head with 0.48 needle electrodes is in use.

FIG. 2 is a conceptual diagram showing the basic structure of an electrostatic recording device using a multi-stylus head. The roller 11 is at a predetermined potential due to the elastic force of the spring 10 so that the roller 11 is in contact with the needle electrode and the control electrode of the multi-stylus head 1.
As the roller 11 rotates in the direction of arrow A, it is sent in the direction of arrow B.

FIG. 3 is a block diagram for explaining the driving method of a conventional electrostatic recording device using a multi-stylus head 1 having 204 needle electrodes.
The first and second needle electrode drive circuits 16 are synchronized with the needle electrode drive circuits 14 and 15 and have different output states and apply recording pulse voltages VA and VB to each needle electrode under the control of an image signal. 65 pairs of control electrode rows 4 (hereinafter referred to as C1, C2, etc.) are provided on both sides of the needle electrode row 3.
...displayed as C65) and set the control pulse voltage V.
This is a control electrode drive circuit that applies c.

2048 needle electrode row 3 (hereinafter each needle electrode is numbered #1 in the order of arrangement)
, #2, . . . #2048.

) is #1, #65, #129, etc. every 64 lines.
...Group 1 (hereinafter referred to as GI), #2, #66, #1, in which 32 #1985 wires are connected in parallel.
30,.・・・．・・・．・・・． ...G2 with #1986 connected in parallel, and G64 connected in the same way, a total of 64
are grouped into groups. Further, the first half of each group is connected to the terminal of the first needle electrode drive circuit 14 in parallel in the order of arrangement, and subgroup A (hereinafter referred to as SG
Display as A. ), and similarly, the latter 3Z' are each connected in parallel to the second drive circuit 15 to form a subgroup B (hereinafter referred to as SGB). Control electrode CI corresponds to 16 needle electrodes #1 to #16, and control electrode C2 corresponds to 3 needle electrodes #17 to #48.
In the same manner, each control electrode C64 corresponds to 32 needle electrodes, and the last control electrode C65 corresponds to 16 needle electrodes. however,
In the above explanation, in order to keep the shape of the control electrode constant, C6
4 and C65 are shown separately, but in reality they do not need to be driven independently, so usually the two electrodes are electrically connected. Note that if the recording pulse voltages VA, VB and the control pulse voltage Vc are applied independently, the electrostatic recording paper 7
The value is set so that a static lightning latent image cannot be formed on the insulating layer 9, and a charge image is formed only in the portion of the needle electrode to which both voltages are applied simultaneously.

FIG. 4 shows the recording pulse voltage V outputted to the output terminal selected by the needle electrode drive circuits 14 and 15 according to the image signal.
A, VB and the waveform of the control pulse voltage Vc applied to each control electrode CI to C65 by the control electrode drive circuit 16. Control electrodes C2 to C64 are each sequentially shifted by a time period t. A control pulse voltage Vc is applied in the form of
#1 to #2048 are applied alternately at a time of 64t.
The needle electrode is configured to finish recording until (hereinafter referred to as
This period 64t is called one scanning period.

), then the recording paper 7 is advanced by one line, and the same recording is repeated to form a sequential latent image of the image, and the image is reproduced through a developing and fixing process. Incidentally, the image reproduced in this manner may have vertical stripes of light and shade, which may degrade the quality of the reproduced image.

The reason why these vertical stripes occur will be explained with reference to FIG. Figure 5 shows the case of recording with needle electrodes #1 to #64, and Figure 5A shows the correspondence between needle electrodes #1 to #64 and control electrodes CI to C3 corresponding to these needle electrodes. The figure shown in FIG. 1B is a diagram showing voltage waveforms at various parts.

In order to record with needle electrodes #1 to #32, a predetermined needle electrode is selected from subgroup SGA according to the image signal and a recording pulse voltage VA is applied to it, and at the same time control electrodes CI and C2 are selected.
When a control pulse voltage Vc is applied to the insulating layer 9 of the recording paper 7 facing the selected needle electrode, the potential of the insulating layer 9 of the recording paper 7 becomes VA + Vc, but this voltage is necessary to form a static exposure latent image on the recording paper. Since the value is set to a certain value, a static exposure latent image is formed by the selected needle electrode.

Next, in order to record with needle electrodes #33 to #64, a recording pulse voltage VB is applied to sample group B, and a control pulse voltage is simultaneously applied to control electrodes C2 and C3.

In this way, VB+Vc is also applied to the recording paper facing the needle electrodes #33 to #64, and a static latent image is formed, but in reality, the size of the static latent image, and therefore the density of the reproduced image, is In addition to the above-mentioned Vc+VA or VB+Vc, the potential on the base paper 8 side of the recording paper has a large influence. That is, if the potential on the base paper side is Vo, then the density D is D=Na(V
A+Vc,V) or D=〆(VB+Vc,Vo)
However, since this Vc is not constant, density unevenness occurs. The voltage waveform on the base paper side of the recording paper 8 is normally the result of differentiating the applied control pulse voltage, and is as shown by Vc to Vc3 in FIG. 5B.
In this waveform, if the voltage in the first half period t is Vp, the voltage in the second half period t is Vq, and the recording pulse voltage is VA=VB=V, then the recording density D in the range of needle electrodes #1 to #32 is D,
=〆(V + Vct Vp), D2 = in #33 to #48
(V + Vc, vq), in #49 to #64, D3=〆(
It can be expressed as V+Vc,vp). When the potential on the base paper side of the recording paper 8 becomes low, the accumulated charge escapes, so for the density D, ~D3, D, = D.
There is a relationship: 2>D3. Above, we have considered the case of recording with needle electrodes #1 to #64, but if we think in the same way, the reproduced image will be dark in the first half where the control pulse voltage Vc is applied, and pale in the latter half, so the vertical It can be seen that shading stripes occur in the direction. The purpose of this invention is to eliminate unevenness in density of reproduced images without reducing the recording speed using a current multi-stylus head. A recording pulse voltage VA or VB is applied to the electrodes. The recording apparatus according to the present invention will be explained below with reference to voltage waveform diagrams shown in FIGS. 3 and 6. Recording pulse voltage VA, V
In B, VA is applied from the drive circuit 14 to the needle electrode selected from among the needle electrodes belonging to SGA during the period from time 0 to time 2 in the first half of one scanning period, and during the period from time t32 to time t64 in the second half, VA is applied to the selected needle electrode from the drive circuit 14. VB is applied from the circuit 15 to a selected needle electrode among the needle electrodes belonging to SGB.

On the other hand, the control pulse voltage Vc is applied to the control electrodes CI and C2 from time 0 to time t, and applied to the control electrodes C3 and C4 from time t to t2, and thereafter is sequentially shifted in the same manner to the time Between t3 and t32, control electrodes C63, C64,
After VA is applied to C65, the recording pulse voltage is switched to VB, and the control electrodes are shifted to control electrodes C2 and C3 between time t32 and t33, and control electrodes C4 and C5 between time t33 and t34, and so on. Finally, the voltage Vc is applied to the control electrodes C64 and C65 between times t and 4 to end the recording of one line. Thereafter, the recording paper 7 is fed one line and the same recording is repeated to form a static lightning latent image, which is no different from the conventional apparatus. Note that in order to perform such driving, it is necessary to insert the order of the image signals, but this is done using a shift register or R
This can be easily realized using memory circuits such as AM.

When such driving is performed, recording is performed only once while the voltage Vc is applied to each control electrode, so the voltage waveform on the base paper 8 side of the recording paper 7 becomes vp, which is always constant. Therefore, the vertical stripes mentioned above are eliminated and the quality of the reproduced image is improved.

Note that when such driving is performed, in order to obtain a reproduced image with an appropriate density, if the recording pulse voltage Vc and the recording pulse voltages VA, VB are each DC voltages of 600 to 700 V, the control pulse voltage Vc The application time is 2 to 3
s is sufficient, and it is possible to record at the same speed as the conventional device, and in the case of the above embodiment, it was possible to record one line of the full width of B4 size at a high speed of 2 ms or less including the feeding time.

FIG. 7 shows a timing pulse generation circuit for controlling the drive circuit 16 through which the control electrodes are driven as described above.
To simplify the explanation, a case is shown in which a single needle control electrode is driven.

In the figure, 17 and 18 are shift pulse generators composed of decoders or ring counters, 21 to 36 are OR circuits, and 17, 18, and 21 to 36 constitute a timing pulse generation circuit 19. The shift pulse generators 17, 18 sequentially send shift pulses alternately from left to right. In the OR circuit that receives this shift pulse, first, 21 and 22 output a control pulse voltage, then in the next step, 23 and 24 output, and in the same manner, control pulses that are shifted one by one are outputted. From this example, a timing pulse generation circuit that outputs N control pulses can be easily constructed. The present invention provides a multi-stylus having a large number of needle electrodes arranged in a line, and a plurality of control electrodes formed in a size similar to that of a predetermined number of needle electrodes disposed near the needle electrode array. In a recording device using a head, during a period when a control pulse voltage is applied to a control electrode, among a plurality of needle electrodes facing the control electrode, the needle electrode facing the picture element of the image signal to be recorded is selected. This feature is characterized in that the recording pulse voltage is selectively applied only once at the same time, and can have a great practical effect in that unevenness in density of reproduced images can be removed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of a multi-stylus head;
Figure 2 is a conceptual diagram showing the basic configuration of an electrostatic recording device;
The figure is a block diagram for explaining the scanning method, Figure 4 is a waveform diagram of the recording pulse voltage and control pulse voltage in the conventional scanning method, and Figure 5 explains the reason for the occurrence of shading in the charge image in the conventional scanning method. FIG. 6 is a waveform diagram for explaining the scanning method according to the present invention, and FIG. 7 is a circuit diagram showing the configuration of a timing pulse generation circuit suitable for application to the present invention. In the figure, 1 is a multi-stylus head, 3 is a needle electrode array, 4 is a control electrode array, 5 and 6 are connectors, 7 is electrostatic recording paper, 9 is an insulating layer, 10 is a spring, 11 is a roller, 14, 15
1 is a needle electrode drive circuit, 16 is a control electrode drive circuit, #1 to #
2048 is a needle electrode, and CI to C65 are control electrodes. Note that the same reference numerals in the figures indicate the same or corresponding parts. Figure 1 Figure 3 Figure 2 Figure 4 Figure 5 Figure 7 Figure 6

Claims (1)

[Claims] 1. A large number of needle electrodes arranged in a line on the path along which the electrostatic recording paper is conveyed, and these needle electrodes are divided into a plurality of groups, and the needle electrodes are provided facing the needle electrodes so as to span each of these groups. Using a multi-stylus head having a plurality of control electrodes, when a control pulse voltage is applied to the control electrode and an image signal is applied to the needle electrode facing the control electrode, charge is accumulated on the electrostatic recording paper. In this apparatus, recording is performed by making one round of the needle electrodes in the row within one running period of the image signal, in which the number of odd-numbered groups of the needle electrodes to be recorded on the electrostatic recording paper is a first needle electrode driving circuit that sequentially applies an image signal corresponding to an odd number group in each group during the first half (or second half) period of one scanning period of the image signal; The image signal corresponding to the even number group to be recorded on the recording paper is stored in the second half (or first half) of one scanning period of the image signal.
Synchronized with the drive timing of the second needle electrode drive circuit and the two needle electrode drive circuits, which sequentially apply data to each group during the period, the two control electrodes facing the drive needle electrode group are sequentially controlled at the same time and with the same time width. and a control electrode drive circuit that applies a pulse voltage, and is characterized in that only one group of needle electrodes is driven when the control pulse voltage of the same time width is applied to the two control electrodes at the same time. Electrostatic recording device using a multi-styler head.