JPS58171969A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To make the inclination of recorded pictures constant regardless of the moving directions of a head by allowing initial ink particle and last ink particle to concurrently reach a recording medium when one scanning line is recorded by plural ink particles. CONSTITUTION:In an electrostatic deflection type ink jet recorder, all charged ink particles are allowed to reach a recording medium at the same time within the period of one scanning line. For example, when one scanning line is recorded by five ink particles 35a-35e, by using a drive voltage of 50kHz, it is necessary to shorten the flying distance of final ink particle 35e by 2mm. as compared with the flying distance of initial ink particle 35a. For this purpose, the recording is inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus, and particularly to a bidirectional scanning type inkjet recording apparatus.

FIG. 1 is a schematic diagram of an inkjet recording apparatus, in which 1 is a recording medium and 2 is a recorded image reproduced on the recording medium. 3
3 is an inkjet recording section, and 31 is a nozzle to which pressurized ink 32 is supplied. A piezoelectric element 33 is attached to the nozzle 31, and an excitation voltage 34 is applied to it, which applies forced vibration to the pressurized ink 32 in the nozzle 31. 35 is a generated ink particle, and 36 is an electric pole for charging the ink particle 35, to which an information signal 37 is applied.

Denoted at 38 are deflection electrodes arranged opposite to each other across the path of the ink particles 35, to which a deflection voltage 39 is applied. While the ink particles 35 are flying between the deflection electrodes, they are deflected according to the content of the information signal 37, and are reproduced as a recorded image 21 on the recording medium 1. Reference numeral 40 denotes a gutter for capturing the charged ink particles 35 so that they do not reach the recording medium 1, and the collected ink is reused.

FIG. 2(a) shows the waveform of the ri excitation voltage 34, which is a sine wave signal. FIG. 2(b) shows the generated ink particles 35,
FIG. 2C shows an example in which the information signal increases over time during one scanning period T, and the deflection angle of the ink droplet 35a becomes the minimum.

FIG. 3 shows an outline of the recording apparatus, and numeral 1 denotes a recording medium, which is transported in the direction of arrow Y by a drive device (not shown). Reference numeral 3 denotes an inkjet recording section, which is transported in the directions of arrows x and x' by a drive device (not shown).

Arrow X is for moving from left to right, and arrow X' is for moving from right to left, so-called moving in both directions and recording in both directions.

Here, when an ink particle is charged with the signal shown in FIG. 2(C) and moves in the direction of arrow X, the recording surface 11!2 becomes as shown in FIG.
a) When moving in the direction of the arrow X' force, the distribution th112 becomes as shown in FIG. 4(b), and the inclination of the image 2 changes depending on the direction of movement. Here, 35a to 35e are reproduced in one 1illi image 21 with five ink particles in one scanning period T, and are done in the order in which the ink particles 35 are generated. The slope varies depending on the direction. In order to solve this drawback, (1) Publication No. 52-11857 changes the magnitude of the information signal in FIG. 2(C) depending on the direction of movement. That is, when moving in the direction of arrow X' force,
By reducing the magnitude of the information signal over time, the inclination of the recording 1 and 2 is kept constant regardless of the direction of movement.

(2) Japanese Patent Application Laid-Open No. 56-46759 changes the mounting angle of the deflection electrode 8 depending on the moving direction to change the deflection electric field.

(3) In 1987-70968, two sets of deflection electrodes are provided and used depending on the direction of movement.

Other methods have been proposed, but they have the drawback that they are complicated, have moving parts, and cannot operate stably over long periods of time.

The present invention eliminates the drawbacks of the above-mentioned prior art and aims at simplifying and stabilizing the inkjet recording device.
I will provide a.

To achieve this objective, the arrival time of the ink droplets to the recording medium is made to be the same in one scanning line period.

In FIG. 4, one scanning line (image) is recorded with five ink particles -35a to -35e, and the ink particles are generated in the order of 35a, 35b, . . . 35e. Therefore, in the conventional method, the ink particles 35a first reach the recording medium 1, then 35b1, 35C, 35d, 35
e had reached.

In the present invention, one scanning line period T of ink particles 358 to 35e
Then, all the ink particles 35a to 35e reach the recording medium 1 at the same time.

For example, when the frequency of the excitation voltage 34 is 50 KHz and the pressure of the pressurized ink 2 is 3 kg/cm'', the flight speed of the ink particles 35 is about 20 m/s.

At a frequency of 50 KHz, the time interval between each ink droplet is 20 μs. Flying speed of ink particles [20m/
In the case of s, in 20 μs, it moves by Q, 4 mm. Therefore, compared to the flight distance of the first ink droplet, the flight distance of the next ink droplet is Q, 4 mm
Just make it shorter. In FIG. 4, one scan 11! il is recorded using five ink particles 358 to 35e. For this purpose, 1'ill put j is 2oμSX5:10
The flight distance f Q of the ink particles 35aKil, -C35e may be shortened by 4 mm x 5 = 2nl m by 0 μs%.

As a specific example of this, as shown in FIG. 5(a), the flight distances of the ink particles 35a and 35e may be shifted by 2 mm.

In this example, one scanning line is recorded with five ink droplets, but generally 7 to 9 ink droplets are used for alphanumeric characters and 18 to 20 for kanji characters, and various ink pressure frequencies are also selected. Even in such an example, if one scanning line is to be recorded, it is sufficient to select such that the first ink droplet 35a and the last ink droplet 35n reach the recording medium at the same time.

In reality, nine ink particles in the vertical direction and seven in the horizontal direction are appropriately charged and deflected using alphanumeric characters to form one character.

When charging ink particles with the signal shown in Fig. 2 (C), the ink particles at the same angle as the turtle (ink particles 35 in Fig. 2 (b)
The flight distance of a) is the longest.

As another example, in one scanning period T as shown in FIG. 2(d),
If the number of Iro becomes smaller as time passes, ink particles 3
The load '*t of 5a is the largest and the amount of deflection is also the largest. In this case, in order for the ink particles 35a to 35e to reach the recording medium 1 at the time of IEI, the configuration should be such that the flight distance of the ink particle 35e, which is emitted the latest in time, is minimized. , this configuration is shown in FIG. 5(b).

As explained above, according to the present invention, one scan #!
When recording with multiple ink droplets, by making the first ink droplet and the last ink droplet reach the recording medium at the same time, the inclination of the recording slag is maintained regardless of the moving direction of the inkjet recording section. Since it is constant, the device can be simplified and stabilized.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional inkjet recording device;
3 is a schematic diagram of the recording apparatus, FIG. 4 is an enlarged explanatory diagram of the recording Fjh1 rule, and FIG. 5 is a schematic diagram of the inkjet recording apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... Recording body, 2... Image 1#, 3... Ink side recording part, 31... Nozzle, 32... N-pressure ink, 33... Pressure 11 element, 34... ...Excitation voltage, 35
... Ink particles, 36 ... Charged electrode, 37 ... Information signal, 38 ... Deflection - whistle 2 figure rod 3 figure potato 4 figure

Claims (1)

[Scope of Claims] 1. It has a means for generating an ink droplet sound, a means for electrostatically deflecting and deflecting the ink droplets, the inkjet generating means is moved relative to the recording medium, and a plurality of sounds are generated within one scanning period. In an inkjet recording device that reproduces information on a recording medium by deflecting ink particles in the same direction as the moving direction of the recording medium, charged ink particles within one scanning line period reach the recording medium at the same time. An inkjet recording device with a patent for this. 2. An inkjet recording apparatus according to item 1, wherein the ink droplet deflection angle increases over time during one scanning period, and the ink droplet flight distance with the minimum deflection angle is the longest. 3. In item 1: - An inkjet recording device in which the deflection angle of the ink droplets decreases over time during one scanning period, and the inkjet recording device is designed to maximize the flight distance of the ink droplets at the maximum deflection angle.