JPH07237296A - Ink jet recording and device thereof - Google Patents

Abstract

PURPOSE:To eliminate a recording dot of being out of place without degrading recording speed. CONSTITUTION:This ink jet recording device provided with plural nozzle electrodes 12a, 12b, 12c,... which discharge ink droplets 10 by electrostatic force, an electrode plate 16 with an opening part 14 which generates an electric field between the nozzle electrodes 12a,... and passes the ink droplets 10 discharged from the nozzle electrodes 12a,..., and an electric charge generator 20 which supplies ions 18 whose polarity is opposite to electric charges which ink droplets own to the ink droplets 10 which have passed through the opening 14. The opening 14 is formed into a circular shape around the flying route of the discharge ink droplets 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called multi-nozzle electrostatic suction type ink jet recording method and apparatus in which ink is drawn out from a plurality of nozzles by an electrostatic force and ejected.

[0002]

2. Description of the Related Art A conventional ink jet recording apparatus of this type comprises a plurality of nozzle electrodes for concentrating an electric field and a common electrode located on the back surface of a recording medium and facing the nozzle electrodes to generate an electric field. It was The ink droplets extracted by the concentrated electric field are attracted to the common electrode, reach the recording medium, and form recording dots.

[0003]

However, in this conventional ink jet recording apparatus, the ink droplets drawn out are charged with the same polarity as the voltage applied to the nozzle electrodes. Therefore, if another ink droplet is ejected from a nozzle electrode in the vicinity before the ink droplet ejected from one nozzle electrode reaches the recording medium, these ink droplets generate a repulsive force due to mutual electric charges. As a result, since the flight path of the ink droplet is affected, there is a problem that the position of the recording dot is displaced.

In order to avoid this problem, there is a method in which the ink droplets are not ejected from the adjacent nozzle electrodes until the ink droplets reach the recording medium. However, this method has a problem that the recording speed is limited because it is necessary to control the driving sequence of each nozzle electrode.

[0005]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an ink jet recording method and apparatus which eliminates the positional deviation of recording dots without reducing the recording speed.

[0006]

The ink jet recording method according to the present invention has been made in order to achieve the above-mentioned object, and ejects ink droplets by electrostatic force, and the electric charge of the ejected ink droplets is reduced. Then, the neutralized ink droplets are attached to the recording medium.

The ink jet recording apparatus according to the present invention is
Using the inkjet recording method according to the present invention, a plurality of nozzle electrodes for ejecting ink droplets by electrostatic force and an ink droplet ejected from the nozzle electrode while generating an electric field between the nozzle electrodes. And an electric charge generator that supplies ions having a polarity opposite to the electric charge of the ink droplet to the ink droplet that has passed through the opening.

[0008]

The ink droplet ejected from one nozzle electrode by electrostatic force advances toward the electrode plate and passes through the opening by the momentum thereof. The ink droplet that has passed through the opening is electrically neutralized by being supplied with ions having a polarity opposite to that of the charge of the ink droplet, by the charge generator. Therefore, no Coulomb force is generated between the ink droplets ejected from the plurality of nozzle electrodes.

[0009]

1 and 2 show an embodiment of an ink jet recording apparatus according to the present invention, and FIG. 1 shows I--I in FIG.
2 is a vertical sectional view taken along the line, and FIG. 2 is a horizontal sectional view taken along the line II-II in FIG. Hereinafter, the present invention will be described with reference to the drawings.

The ink jet recording apparatus has a plurality of nozzle electrodes 12a, 1 for ejecting ink droplets 10 by electrostatic force.
2b, 12c, ... And a nozzle electrode 12a ,.
・ Aperture 14 for passing ink droplets 10 ejected from
And an electric charge generator 20 that supplies ions 18 having a polarity opposite to the electric charge of the ink droplet 10 to the ink droplet 10 that has passed through the opening 14. The opening 14 is formed in a circular shape centering on the flight path of the ejected ink droplet 10.

The nozzle electrodes 12a, ... Are thin conductors and are provided on a flat plate 30 made of an electrical insulator such as synthetic resin or ceramics. The flat plate 30 is provided with a gap 34 of about 100 [μm] and faces the flat plate 32 which is also made of an electrical insulator. Ink 36 is supplied to the gap 34 from an ink supply unit (not shown). Ink drop 10
When the ink is ejected, the consumed ink 36 is replenished, so that the ink meniscus is always formed in the gap 34. That is, the nozzle electrodes 12a, ..., The flat plate 30,
The recording head 37 as a slit-shaped nozzle is constituted by 32, the gap 34, and the like. In addition, the nozzle electrode 1
A drive pulse source 38 and a bias voltage source 40 are connected to 2a, ....

The electrode plate 16 includes nozzle electrodes 12a, ...
And a recording medium 42, and is formed in a box shape from a conductor such as metal. A charge generator 20 is housed inside the electrode plate 16. Since the electrode plate 16 is grounded as shown in FIG. 1, the nozzle electrodes 12a ,.
An electric field for drawing out the ink 36 can be generated between and. It also functions as a shield plate for the charge generator 20.

The charge generator 20 includes a charger wire 4
4, 46 and a high voltage power supply 48 for applying an AC high voltage between the charger wires 44, 46.

Next, the operation of the ink jet recording apparatus according to the present invention will be described.

A bias voltage of about 700 [V] is applied to the nozzle electrodes 12a, ..., A drive pulse of about 300 [V] is superimposed on the bias voltage from a driver (not shown) according to the recording pattern. Is applied. The ink 36 is not drawn out only by the bias voltage, but when a drive pulse is applied, the ink 36 is drawn out from the ink meniscus,
The ink drops 10 fly and fly. The ink droplet 10 ejected from the recording head 37 passes through the opening 14 of the electrode plate 16 and enters the charge generator 20. An AC voltage of -1 [kV] to 1 [kV] is applied to the charger wires 44 and 46 of the charge generator 20, and the electrode plate 16 is filled with ions 18 having positive and negative polar charges. is doing. Therefore, the ink droplet 10 immediately after being ejected has a positive charge of the same polarity as that applied to the nozzle electrodes 12a, ..., However, after entering the charge generator 20, the charge of the ink droplet 10 is changed. Is instantly neutralized. The ink droplet 10 then continues to fly due to inertia, reaches the recording medium 42, and forms a recording dot. Since the charge of the ink droplet 10 that has entered the charge generator 20 is immediately neutralized, before the ink droplet 10 ejected from one nozzle electrode 12a, ...
Another ink droplet 1 from the adjacent nozzle electrodes 12a, ...
Even if 0 is ejected, the repulsive force that changes the flight paths of the ink droplets 10 does not occur, so the recording dot position does not shift.

[0016]

According to the present invention, the Coulomb force acting on the ink droplets interacts with each other by neutralizing the charge of the ink droplets discharged by the electrostatic force between the nozzle electrode and the electrode plate by the charge generator. Can be suppressed. Therefore, even if the ejection of the ink droplets between the adjacent nozzle electrodes is not adjusted in time, the positional deviation of the recording dots does not occur, and the high-speed and high-quality recording can be performed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view taken along the line II in FIG. 2, showing an embodiment of an inkjet recording apparatus according to the present invention.

2 is a cross-sectional view taken along line II-II in FIG. 1, showing an embodiment of the inkjet recording apparatus according to the present invention.

[Explanation of symbols]

 10 Ink Drops 12a, 12b, 12c Nozzle Electrode 14 Opening of Electrode Plate 16 Electrode Plate 18 Ion 20 Charge Generator

Claims (3)

[Claims] 1. An inkjet recording method comprising ejecting an ink droplet by electrostatic force, neutralizing the electric charge of the ejected ink droplet, and adhering the neutralized ink droplet to a recording medium. 2. A plurality of nozzle electrodes for ejecting ink droplets by electrostatic force, and an electrode plate having an opening portion for generating an electric field between the nozzle electrodes and passing ink droplets ejected from the nozzle electrodes. An ink jet recording apparatus comprising: a charge generator that supplies, to an ink droplet that has passed through the opening, ions having a polarity opposite to that of the charge of the ink droplet. 3. The inkjet recording apparatus according to claim 2, wherein the opening has a circular shape centered on a flight path of the ejected ink droplet.