JPS59167280A - Voltage application method in current supply transfer recording system - Google Patents

Abstract

PURPOSE:To prevent the pulling-off of a multi-head and to obtain good printing quality by low applied voltage in current supply transfer recording using a multi-stylus. CONSTITUTION:All styli (a) are divided into blocks each comprising N-number of styli and time sharing driving is performed so as not to partially superpose voltages applied to styli in each block. That is, one line is constituted so that needle like electrode 1 arranged in a zigzag pattern comprising 32 styli is divided into, for example, four blocks each comprising eight styli and pulse voltages based on image signals are simultaneously applied to the first, 9-th, 17-th and 25-th electrodes in each block while, simultaneously with the falling of these pulses, next pulse voltages are applied to the second, 10-th, 18-th and 26-th electrodes in each block. Hereinafter, pulse voltages are applied so as not to be superposed in each block. As mentioned above, by providing intervals between of adjacent electrodes to which voltages are simultaneously applied, the mutual action between the electrodes is avoided. Each interval is pref. provided at a four-dot pitch (each interval of the adjacent styli is one dot pitch) or more. By this mechanism, the pulling-off of a multi-head is eliminated and a vertical line is also certainly recorded in the same manner as a horizontal line while a noise-wise recording is also eliminated and good printing quality is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage application method in an electrical transfer method for recording dots on recording paper.

Previously, when recording using the electric transfer method, the drum was scanned with a single needle, but the recording speed was slow;
Therefore, the line density had to be coarsened, 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 a voltage is applied to each needle electrode and the return electrode, adjacent needle electrodes are shielded from each other by other electric fields and the needle electrodes The effective area of the current path from the acicular electrode to the return electrode becomes smaller and the resistance increases, resulting in a phenomenon in which the current flowing from the needle electrode to the return electrode becomes smaller. 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.

OBJECTS In view of the above circumstances, the present invention aims to provide a voltage application method in a multi-stylus current transfer system that prevents multi-dot omission and provides good print quality with a low applied voltage.

The structure of the present invention will be described below based on examples.

Figures 2 and 3 are electrode arrangement diagrams and applied voltage waveform diagrams for explaining the present invention in detail, and 1 is a staggered needle-shaped electrode consisting of 32 styli in one row, and 2 is a return path. The 32 styli electrodes are divided into, for example, 4 blocks of 8 each, and as shown in Figure 3, pulses based on image signals are simultaneously applied to the first, 9th, 17th, and 25th electrodes of each block. Apply voltage, and at the same time as this pulse falls, the next electrodes 2nd, 10th, 18th of each block
The next pulse voltage is applied to the 26th and 26th pulses.

Apply pulse voltages in the same manner to the 8th, 16th, 24th, and 32nd blocks so that they do not overlap (Staggered method) - Leave an interval between adjacent electrodes to which voltages are applied simultaneously in this way. This avoids interaction between the electrodes, and the spacing is 4 dots pitch (
The distance between adjacent styli is preferably 1 dot pinch or more, preferably 8 dot pinch or more. By the way, conventionally,
As shown in Figure 4, a voltage (pulse width 100 μs, voltage 170'V) was applied simultaneously to 32 styli; however, the voltage application method using the staggered method was more effective than the conventional simultaneous voltage method. The printing speed becomes 17N (N is the dot pitch). However, by increasing the applied voltage to 300V, the conventional 100μ
s, it is possible to record in a short time of 1/8 of 12°5μs, and the conventional printing speed of 300mm/S can be maintained.
Does not cause any practical problems. In addition, in the voltage application method using the staggered method, conventionally, as shown in Fig.
Since the voltage is applied at 2Duty, the dots corresponding to the 1st and 8th styli will have a deviation of 172 dot pitch (actually 30 μm at a linear velocity of 300 ns). It's 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, and the principle is based on the voltage application method (Staggere) shown in FIG.
d method), the only difference being that only the pulse width is doubled and overlaps with the adjacent stylus by 172 of the pulse width (modified staggered method). By extending the pulse width in this way, the applied voltage can 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 of FIG.
Two styli are applied simultaneously to the adjacent stylus in turn,
A decrease in current occurs.

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, 25th) and tail stylus (8th, 16th)
There is no overlap between the first half and the second half of the pulses applied to the stylus at the head and tail and the stylus at the middle, but the difference is not that great. Since it falls within the range of variation in dot density, there is no 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 1 to 1 of the drive circuit. A indicating a character specified from 10 such as CPU or address counter
Input DR to ROMII and output the character pattern. On the other hand, a signal S indicating the beginning of a character is transmitted to two monostable multivibrators 12 (MMO) and 13 (M
Enter in M1).

Monostable multivibrators 12 to 20 are all C
=0.01 μF+ Ro=4.3 kΩ, R1=6.
8 and Ω. The MMI outputs φ1 with a pulse width of 25 μs. Then, the inverted value of ψ1 is input to the next MM2, and ψ3, which rises when ψ1 falls, is obtained. Similarly, ψ5. ψ7 is obtained.

Also, from MMO's 100, it is 12.5 μs from the rise of S.
A pulse signal which is an inverted version of the pulse having a pulse width of 12.
A pulse φ2 of 25 μs width that rises with a delay of 5 μs is obtained,
Similarly, ψ4. ψ6. ψ8 is obtained. These ψ1~
Add ψ8 and character pattern output to AND circuit 21, and
D circuit output is applied to driver 22 to drive each stylus. Note that +5V is applied to (1) 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 lonilla. Also, it is not necessary to limit the division of the stylus to eight. In addition, the stylus is not divided into only one column, but is divided into two columns as shown in Fig. 9, and the stylus is also divided into two columns as shown in Fig.
It may be driven by the red 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 ψ1 to ψ8 are input to the AND circuit in FIG.

According to this method, in the case of FIG. 10, the fifth stylus becomes the first and second styli to which the pulse voltage is applied at the same time, and the fifth stylus is pulled out more independently than in the case of the embodiment of FIG. 6. A dot close to that of is 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 there is no noise in recording or marking, resulting in good print quality. In addition to being able to record at a lower voltage than the staggered method, the method has less adverse effect on the life of the multi-stylus and requires a lower breakdown voltage of the driver.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between the number of styli and the current flowing through the stylus (center), Fig. 2 is an electrode arrangement diagram for explaining the present invention in detail, and Fig. 3 is a diagram for explaining the principle of the present invention. FIG. 4 is a diagram showing a conventional voltage application method, FIG. 5 is a diagram showing dot misalignment, FIG. 6 is a diagram showing an example of a voltage application method according to the present invention, and FIG. 7 is a diagram showing a drive circuit according to the present invention. 8 is a timing chart, FIG. 9 is a diagram showing a modification of the embodiment of FIG. 6, and FIG. 10 is a diagram showing another embodiment of the voltage application method according to the present invention. be. 1... Needle electrode, 2... Return electrode, 1o... CPU or counter, etc., 11... ROM, 12-2o... monostable multivibrator, 21... AND circuit,
22... Driver. Figure 1

Claims (1)

[Claims] In the current transfer recording method using multi-styli,
In one or more stylus rows, all the styli in the row are divided into blocks of N styli, and voltage application to the styli in each block is driven in a time-division manner so that the voltages are partially overlapped. Application method.