JPS591596B2 - Inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus that applies an information signal to ink particles to record and reproduce an information image.

This type of inkjet recording device reproduces an information image by controlling minute ink particles using information signals and adhering them to a recording medium to form dots. There are various negative effects such as being subjected to air resistance and the subsequent ink particles not being properly charged by the preceding charged particles when the ink particles are charged, resulting in so-called recording distortion in which dots are not formed in the correct position. Ta.

One possible solution to this problem is, for example, to charge the ink droplets with an information signal whose amplitude decreases over time as shown in Figure 3e, and to form the ink droplets in order from the one with the largest amount of deflection to the one with the smallest amount of deflection. However, as described below, it was not always satisfactory.

FIG. 1 is a schematic diagram of an inkjet recording apparatus. Reference numeral 1 indicates a nozzle to which pressurized ink 2 is supplied, and the nozzle 1 is subjected to vibration by a piezoelectric element 3 excited by a high frequency power source 4.

Ink particles 5 are generated every vibration period of the nozzle 1.

Reference numeral 6 denotes a charging electrode j to which an information signal source 1 for imparting charge to the ink particles 5 is connected.

Of the pair of deflection electrodes Ba and 8b, a predetermined deflection voltage is applied to Ba from a deflection voltage source 9, and 8b is grounded. When the polarity of the deflection voltage source 9 is reversed with respect to the charging polarity of the ink droplets, the charged ink droplets 5 are deflected toward the deflection electrode Ba, reach the recording medium 10, and are recorded. The uncharged ink particles travel almost straight, hit the gutter 11, and are removed so as not to reach the recording medium 10. 5. Figures 2a to 2c show the recording dot pattern 12, and Figure 2a is the pattern to be recorded, which is assumed to be recorded in the numerical order of the dots.

For the sake of simplicity, to explain the case where one pattern is recorded using a dot matrix with 4 rows and 5 columns, first, the dots in the 1st row are recorded, followed by the dots in the 2nd, 3rd, and 4th rows. A dot is recorded. The time during which each row is recorded will be referred to as one scanning period T.

FIG. 3 shows the signal waveform for recording this FIG. 2a.

FIG. 3a shows a high frequency signal waveform applied to the piezoelectric element 3, which causes ink particles to be generated from the tip of the nozzle 1 with a phase as shown in b.

c is a waveform-shaped signal of the high-frequency signal a, which is the information signal source 7.
used as a clock signal. d is an output signal from a character signal source, such as a character generator, e is an information signal converted by a known method, and in this case, T1-T'4 are each 1. During the scanning period, for example, the first line in FIG. 2a is recorded at T1, the second line at T2, and the fourth line at T4. Naturally, the time intervals T1-T2-T3-T4 are all the same. Figures 2B and 2c show examples of dot patterns recorded when the pressure of the pressurized ink supplied to the nozzle 1 in Figure 1 is varied; Figure 2b is the case when the pressure is low;
The printing position of the first column is different between each row, particularly the first and fourth lines where only one particle of the first column is printed, and the third and fourth lines where ink particles are continuously charged, and there is a deviation d1. Furthermore, 3,4
In the row, there is a gap D2 between the first column and the second column. FIG. 2C shows the case where the pressure is increased.

In this case, the printing position in the first column of each row is almost the same, but there is a gap D3 between the first and second columns of the third and fourth rows, where ink particles are charged successively. Only. FIG. 4 shows an example actually recorded, in which the aperture of the tip of the nozzle 1 in FIG.
When the recording width is D-20m71L1 and the number of ink particles in one scanning period is 32 at 5KHz, a is the ink pressure - 0.751<g/Clll, and b is the ink pressure - 0.751<g/Clll.
9kg/? This is an example when

It can be seen that the trend is as shown in Fig. 2 B and c. To this end, conventionally proposed methods of lowering the information signal level of mere preceding ink particles or isolated ink particles, or increasing the information signal level of ink particles following the preceding ink particles, are as shown in Fig. 2. It was not possible to correctly correct the distortion of b, that is, the misalignment and gap in the print.

The present invention has been made in view of the above, and an object of the present invention is to provide an ic-jet recording device that can electrically prevent recording distortion.

The present invention can be applied to the leading ink droplet when two or more ink particles are charged in succession, the isolated ink droplet that is not consecutively charged but only one ink droplet, or the first column of each scanning period (the head of the matrix). The charging information signal level of the ink droplet corresponding to the position) is lowered by the correction signal.

FIG. 5 shows the circuit configuration of one embodiment of the information signal source of the present invention,
FIG. 6 shows the signal waveforms of the main parts.

In FIG. 5, 21 is a waveform shaping circuit whose output signal waveform is shown in FIG. 6a and is used as the following clock signal (same as in FIG. 3C). 22 is a counter for determining one scanning period T and controlling the character signal generation source 23.

FIG. 6b shows the output signal of the character signal generation source 23, and FIG. 3d shows the output signal of the character signal generation source 23.
is the same as

24 is a detection circuit for detecting preceding ink particles and isolated ink particles, and is composed of, for example, a monostable multivibrator.

Its Q output is shown in FIG. 6C. 25 is an AND circuit which performs an AND operation between FIG. 6a and FIG. 6b, and outputs FIG. 6d.

26 is a function generator which outputs the signal f in FIG.

Although a staircase wave generator is used in this example, a sawtooth wave generator may also be used. 27 is a pulse width converter, and its Q output waveform is shown in FIG. 6g.

This signal has the same time relationship as the information signal that charges the ink droplets in the first column of each row. 28 is an OR circuit which connects the Q output of the detection circuit 24 (FIG. 6c) and the Q output of the pulse width converter 27.
Output (in the inverse relationship of Fig. 6g).

) and outputs h in Figure 6. 29 is an AND circuit, which outputs the Q output of the detection circuit 24, Fig. 6G, Fig. 6b
AND is performed and the result shown in FIG. 6 is output.

30 is a differential amplifier which inputs the signals shown in the figure and outputs the signal shown in FIG. 6j.

In Fig. 6j, ERl is the correction amount due to signal 1, ER
2 is the correction amount due to the signal h. Reference numeral 31 denotes a synthesizing circuit which synthesizes FIG. 6 d and FIG. 6 j and outputs FIG. 6 k.

32 is an image amplifier which inputs the signal k in FIG. 6 and amplifies it to a required value for charging the ink droplets.

The waveform shape is the same as that in FIG. 6k. In Fig. 6k, the solid line indicates the first correction (corresponding to ERl in Fig. 6j);
The second correction (corresponding to ER2 in FIG. 6j) is performed, and the dotted line is the signal level when these corrections are not performed (corresponding to FIG. 3e).

From FIG. 6, for example, isolated ink particles (corresponding to 1 in FIG. 2), preceding ink particles (corresponding to 2 in FIG. 2), and even third
The signal levels of the particles in the row 1 column (corresponding to 7 in FIG. 2) and the particles in the 4th row and 1 column (corresponding to 12 in FIG. 2) are lower than the conventional signal level by the second correction signal ER2, Other than the above ink particles (corresponding to 3 to 6 and 8 to 11 in Figure 2)
is the first correction signal ERl and is higher than the conventional signal level.

By charging the ink particles with this signal, the
It is possible to obtain a recording example that is almost similar to the pattern of . FIG. 4C shows an example of recording when correction was actually performed using the correction signals ERl and ER, and there was no recording distortion like that shown in FIGS. 4A and 4B, and a practically sufficient recording example could be obtained. As explained above, the present invention detects the charging of an isolated recording ink droplet or the leading one of a continuous charging, and the charging of the recording ink droplet at the matrix position at the beginning of each row. Since the information signal level for charging recording ink particles is corrected to a low level, a good information image without recording distortion can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an outline of the IC jet recording device, Fig. 2 is an example of dot pattern recording, Fig. 3 is a conventional operation signal waveform diagram, Fig. 4 is an information image actually recorded, and Fig. 5 is an example of recording a dot pattern. FIG. 6 is a block diagram showing the circuit configuration of the information signal source, and FIG. 6 is a diagram of its operating signal waveforms. 1... Nozzle, 2... Pressurized ink, 3
...Piezoelectric element, 4...High frequency power supply, 5
...Ink particles, 6...Charging electrode, 7
... Information signal source, 8 ... Deflection electrode, 9
... Deflection voltage source, 10 ... Recording body, 2
1...Waveform shaping circuit, 22...Counter, 23...Character signal generation source, 24...
・Detection circuit, 26...Function generator, 27...
... Pulse width converter, 28 ... OR circuit, 3
0...Differential amplifier.

Claims (1)

[Claims] 1 means for generating ink particles; means for generating an information signal whose signal level gradually decreases over time within one scanning period; means for charging recording ink particles with the information signal; a deflecting means for deflecting recording ink particles by an amount corresponding to the amount of charge and adhering to the recording medium, and a row of dots formed by the recording ink particles adhering to the recording medium in an arrangement in the deflection direction. In an inkjet recording apparatus in which a dot matrix is formed by arranging a plurality of dots in a plurality of rows in a direction perpendicular to the recording ink droplet, a first detection means detects whether a recording ink particle is isolatedly charged or is at the forefront of a continuous charge; A second detection means detects that the recording ink particles at the first matrix position of each row are charged, and a correction means lowers the information signal level based on the outputs of the first and second detection means. An inkjet recording device characterized by: