JPS5848353B2 - inkjet plotter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink jet printer having a plurality of two nozzles and printing by charging and deflecting ink droplets ejected from each nozzle.

FIG. 1 is a diagram showing an example of a conventionally well-known inkjet printer. In the figure, numerals 10, 20, and 30 are inkjet heads, and for example, 60 inkjet heads are arranged perpendicularly to the traveling direction of the recording paper 40. They are lined up.

In addition, IL21 and 31 are ultrasonic transducers such as electrostrictive transducers,
12, 22.32 are charged electrodes, 1 3a, 1 3b
, 23a, 23b, 33a-33b are deflection electrodes, 1
4, 24, and 34 indicate an unnecessary ink drop collection gutter, and as is well known, the inkjet head 1 is driven once by an excitation signal applied between terminals a and b, and an ink liquid column is ejected from its nozzle. When the ink liquid column is separated into ink droplets by applying a charging voltage according to the printing information signal between the terminals crd, the ink liquid column is selectively charged, and the deflection electrode is used to charge the ink droplet in a direction perpendicular to the traveling direction of the recording paper 40. For example, desired characters, symbols, figures, etc. are printed on the recording paper by applying a deflection of 60 dont/5 mm to each nozzle, while unnecessary ink droplets not used for printing are collected by the ink collection gutter 14.24.
34 into the ink tank 50, and the pump 60,
The ink is returned to the inkjet head 1 through a filter 70 for reuse.

In the above-mentioned type of inkjet printer, it is difficult to adjust the seam between the printing parts of each nozzle. For example, if the printing part by the inkjet head 10 and the printing part by the inkjet head 20 are too far apart,
As shown in Figure 2b, it appears as a white sushi, and if it is brought too close, it appears as a black streak as shown in Figure 2b, which is not desirable in terms of quality.

Furthermore, even if the adjustment is made initially, there is a risk that the adjustment may be lost due to changes in the ink over time, fluctuations in the input voltage, or the like.

The present invention eliminates the drawbacks of the prior art as described above, and improves the overall image quality by making the seams of the nozzle printing part less noticeable. An example of this is shown in Fig. 3. .

In FIG. 3, 100 is, for example, a 60×60 dot shift register, 110 is a switching circuit, 120 is a charging electrode array, 130 is a charging pulse generation circuit, 140 is a charging information signal generation circuit, 150 is a charging information signal amplification circuit, and 160 is a charging information signal amplification circuit. An AC or nozzle signal generation circuit, 170 is an excitation circuit, 180 is an ultrasonic vibrator, reads data into the shift register 100 by a data clock, and then
The transferred data is transferred to the switching circuit 110 by the printing clock, and only when the output of the shift register 100 is at a high level, the switching circuit 110 is opened and the charging electrodes of the charging electrode array 120 are transferred to the switching circuit 110. A voltage is applied to charge the ink droplets.

Next, the optimal charging phase for charging the ink droplet is detected by a detection electrode (not shown), and the charging pulse generation circuit 130 is controlled based on this optimal charging phase to determine the timing of charging, and the charging information signal generation circuit 140 detects, for example, 60 stages. A charge information signal amplification circuit 160 performs digital-to-analog conversion to generate, for example, a 60-step staircase wave signal.

It is well known that ink droplets are loaded with this step wave signal, but if this is done, white streaks and black streaks appear at the seams between the printing sections of each nozzle as described above, resulting in poor image quality.

The present invention was made to eliminate such drawbacks,
As shown, an AC or nozzle signal generation circuit 160 is provided, and a signal from the AC or nozzle signal generation circuit 160 (see FIG. 4b) is applied to the ink to be deflected to the end of the printing section of each nozzle. The excitation circuit 170 receives the step wave signal (see FIG. 4a) when a droplet is cut from the ink column.
(see Fig. 4C), the ultrasonic transducer 1
If the amplitude or phase of the excitation voltage applied to 80 is changed appropriately, the diameter of the ejected ink droplets will change slightly, the printing position will be slightly shifted, and although the resolution of the seam will be slightly worse, there will be no white smudges or black streaks. becomes less noticeable, and the overall image quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional inkjet processor, FIG. 2 is a diagram showing an image printed by the conventional inkjet printer, and FIG. 3 is an example of an inkjet processor according to the present invention. Electrical circuit diagram for illustrating examples, No. 4
The figure is an electrical signal waveform diagram for explaining the operation of the circuit of FIG. 3. 10, 20, 30... Inkjet head,
11,21.31... Ultrasonic transducer, 1 2
, 22, 32... charged electrode, 13a-13b,
23a, 23b, 33a, :33b-.・．． deflection electrode,
14, 24, 34... Ink collection gutter
40... Recording paper, 5 0... -...Ink tank, 60...Pump, 70...Filter, 100...Shift register, 110...
...Switching circuit, 120...Charging electrode array, 130...Charging pulse generation circuit,
140... Charge information signal generation circuit, 150...
... Charge signal amplification circuit, 160 ... AC or noise signal generation circuit, 170 ... Excitation circuit,
180... Ultrasonic vibrator.

Claims (1)

[Claims] 1. In an inkjet processor having a plurality of nozzles, a plurality of charging electrodes for charging ink droplets ejected from each nozzle, and a plurality of deflection electrodes for deflecting the charged ink droplets, each The amplitude or phase of an excitation signal that excites the nozzle and causes the ink droplet to be ejected from the nozzle is controlled when the ink deflected from the nozzle to the outermost printing part is separated into ink droplets from the ink liquid column. An inkjet professional soter characterized by slight changes.