JPH055666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electrical transfer recording device that records dots on recording paper.

Prior Art Conventionally, in recording by the current transfer method, recording was performed by scanning a drum with a single needle, but the recording speed was slow, so the linear density had to be coarse, and the resolution was low. Therefore, an ink sheet is brought into contact with the recording paper, and a large number of needle-like electrodes arranged in a row on this ink sheet are in contact with return-path electrodes arranged at predetermined intervals. A multi-stylus current transfer recording method has been proposed in which an image signal voltage is applied between the electrode and the ink sheet directly below the needle-shaped electrode to melt the portion and transfer it to recording paper. However, in such a recording method, interaction occurs between the needle electrodes, and when voltage is applied to each needle electrode and the return electrode,
Adjacent needle-shaped electrodes are shielded from each other by other electric fields, and the effective area for the current path from the needle-shaped electrode to the return electrode becomes smaller, increasing the resistance, and as a result, the current flowing from the needle-shaped electrode to the return electrode becomes smaller. A phenomenon occurs. Figure 1 is a diagram explaining this phenomenon, where the horizontal axis shows the number of needle-like electrodes and the vertical axis shows the current flowing through the needle-like electrode (center).The current decreases as the number of needle-like electrodes increases. . If the current decreases in this manner, the ink sheet will not be sufficiently melted, resulting in multi-dot omission, uneven printing, and especially the problem that no vertical lines will appear.

Purpose In view of the above circumstances, the present invention aims to provide a multi-stylus current transfer recording device that can prevent multi-dot omission and provide good print quality with a low applied voltage.

Configuration In order to achieve the above object, the present invention divides a plurality of electrodes into blocks of N electrodes, simultaneously applies a pulse based on an image signal only to a predetermined first electrode of each block, Next, in an electric transfer recording apparatus that sequentially applies pulses to the second, third, ..., Nth electrodes of each block based on the image signal, the pulses applied to the electrodes being driven in the block are This is characterized in that the pulse applied to the next electrode in the block partially overlaps in time. The following will explain based on examples.

Figures 2 and 3 are electrode arrangement diagrams and applied voltage waveform diagrams for explaining the principle of the present invention, where 1 is a staggered needle-like electrode with one row consisting of 32 styli, and 2 is a return path. It is an electrode. For example, the 32 styli are divided into 4 blocks of 8 each, and as shown in Figure 3, pulse voltages based on image signals are applied simultaneously to the first electrodes 1, 9, 17, and 25 of each block. However, at the same time as this pulse falls, the next electrodes of each block, 2nd, 10th, 18th, etc.
Apply the next pulse voltage at the 26th point. The pulse voltages are similarly applied to the 8th, 16th, 24th, and 32nd blocks so that they do not overlap (staggered method). Interaction between electrodes is avoided by providing a spacing between adjacent electrodes to which voltages are applied at the same time, and this spacing is at least 4 dot pitches (the spacing between adjacent styli is 1 dot pitch), preferably at least 8 dot pitches. is good. By the way, conventionally, voltage (pulse width) was applied simultaneously to 32 styli as shown in Figure 4.
100μS, voltage 170V) was applied, but
In the voltage application method using the staggered method, the printing speed is 1/N (however, N is dot pitch) compared to the conventional simultaneous voltage method. However, by increasing the applied voltage to 300V, it became possible to record for a short time of 12.5μS, 1/8 of the conventional 100μS.
The conventional printing speed of 300mm/S can be maintained without causing any practical problems. In addition, in the voltage application method using the Staggered method, conventionally, as shown in Figure 5, 1/2
Since the voltage is applied at the duty, the dots corresponding to the 1st and 8th styli will be shifted by 1/2 dot pitch (actually 30 μm at a linear velocity of 300 mmS), but this is hidden by the variation in the dot size and is not visible to the naked eye. is not a problem.

However, when time-division driving is performed so that the drive pulses do not overlap at all, the applied voltage must be as high as 300V in order to maintain the conventional printing speed, which adversely affects the stylus and reduces overall reliability. In addition, it requires a driver with higher pressure, which is disadvantageous in practice.

FIG. 6 is a diagram showing an embodiment of the voltage application method according to the present invention. The principle is exactly the same as the voltage application method (Staggered method) shown in FIG. 3, except that only the pulse width is doubled. The only difference is that the pulse width overlaps with the adjacent stylus by 1/2 of the pulse width (modified staggered method). By extending the pulse width in this way, the applied voltage could be lowered, and in this example, recording was possible at 230V. However, in this modified staggered method, the pulses applied to each stylus are not completely separated and independent among the eight pulses in one block, and in the example shown in Figure 6, the pulses applied to the adjacent stylus are alternated by 1/2 of the pulse width. are applied simultaneously, resulting in a decrease in current. In this case, the current decreases by 20 to 25%, which corresponds to the case of changing from a single stylus to a dual stylus in Figure 1, but with this degree of decrease, the dot density is almost the same as in the case of a single stylus. is obtained, and there is no problem in practical use. Also, the stylus at the head of each block (1st, 9th, 17th
The first half and the second half of the pulses applied to the head and tail styli (8th, 16th, 24th, and 32nd) do not overlap with each other; Although there is a difference in dot density, the difference is not that large and falls within the range of variation in dot density, so it does not pose a problem visually.

FIG. 7 is a diagram showing an example of a drive circuit according to the present invention, and FIG. 8 is a timing chart thereof.
An ADR indicating a character designated by 10 such as the CPU or an address counter is input to the ROM 11, and a character pattern is output. On the other hand, a signal S indicating the beginning of a character is input to two monostable multivibrators 12 (MM0) and 13 (MM1). Monostable multivibrator 12~
All 20 are C = 0.01μF, R ₀ = 4.3kΩ, R ₁ = 6.8kΩ
It is. MM1 outputs φ1 with a pulse width of 25 μS. Then, φ3, which rises when φ1 falls, is obtained. Similarly below, φ5, φ7
is obtained. In addition, from MM0, a pulse signal which is an inverted version of the pulse having a pulse width of 12.5 μS from the rising edge of S is obtained, and by inputting this to MM5, a pulse signal φ2 with a width of 25 μS that rises 12.5 μS later than φ1 is obtained. is obtained, and φ4, φ6, and φ8 are obtained in the same way. These φ1 to φ8 and character pattern output
In addition to the AND circuit 21, the AND circuit output is applied to the driver 22 to drive each stylus. In addition,
+5V is applied to V1, and a recording voltage is applied to V2.
In FIG. 7, only the driving of 32 styli in one row has been described, but it is sufficient to repeat exactly the same process for the staggered structure of 32×2 styli. Furthermore, the stylus is not limited to a staggered structure, but may have a single row, and the return electrode may not be integrated with the needle electrode, but may be provided separately, for example with a roller or the like. Also, it is not necessary to limit the division of the stylus to eight. Also, the stylus is divided into 1
Instead of using just the columns, it may be divided into two columns as shown in FIG. 9, and similarly driven using the modified staggered method.

FIG. 10 is a diagram showing a voltage application method in another embodiment of the present invention, in which the order of the applied pulses within one block of FIG. 6 is reversed. This can be achieved by simply changing the order in which φ1 to φ8 are input to the AND circuit in FIG. According to this method, the first
In the case of Figure 0, the fifth stylus is the first and second stylus to which the pulse voltage is applied at the same time, and they are further apart than in the example of Figure 6.
Dots that are closer to individual dots can be obtained.

Effects As described above, according to the voltage application method of the present invention, multi-dot omission is eliminated, vertical lines are recorded as reliably as horizontal lines, and noisy recording is eliminated, resulting in good print quality. as well as obtained
It can record at a lower voltage than the staggered method, has less negative impact on the lifespan of the multi-stylus, and requires a lower withstand voltage of the driver.

[Brief explanation of drawings]

Figure 1 shows the number of styli and the stylus (center)
Figure 2 is an electrode arrangement diagram to explain the principle of the present invention, Figure 3 is a diagram to explain the principle of the present invention, Figure 4 is a graph showing the relationship between the current flowing through the FIG. 5 is a diagram showing dot misalignment. FIG. 6 is a diagram showing an embodiment of the voltage application method according to the present invention. FIG. 7 is a diagram showing an embodiment of the drive circuit according to the present invention. Figure 8 is a timing chart.
FIG. 9 is a diagram showing a modification of the embodiment shown in FIG. 6, and FIG.
The figure is a diagram showing another embodiment of the voltage application method according to the present invention. 1... Needle electrode, 2... Return electrode, 10...
CPU or counter, etc., 11...ROM, 12-2
0... Monostable multivibrator, 21
...AND circuit, 22...driver.

Claims (1)

[Claims] 1 Divide the plurality of electrodes into blocks of N electrodes, apply pulses based on the image signal simultaneously only to the predetermined first electrode of each block, and then apply pulses to the second, third, and third electrodes of each block simultaneously. . . ., in a current transfer recording apparatus that sequentially applies pulses to the Nth electrode based on an image signal, a pulse applied to the electrode being driven in the block;
An electrical transfer recording apparatus characterized in that a pulse applied to an electrode subsequently driven within the block is made to partially overlap in time.