JPS6135257A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To make it possible to make a nozzle having a good responding property and into a multinozzle easy by applying a potential difference between the inside electrode of a section contacting to the ink in the ink chamber and the outside electrode at the front or the rear side of the ink discharge port. CONSTITUTION:A discharge port 6 is provided at the end of the ink chamber 7 of an ink nozzle 20, and an inside electrode 8 is provided at a section contacting to the ink in the ink chamber. An outside electrode 9 is provided at the same side of the discharge port 6 facing recording paper 10, and the front surface 11 of the electrode is positioned flush with the front surfact of the nozzle 12 or somewhat in the rear thereof. The ink is changed into drops 14 and fly against the recording paper 10, owing to the force applied to the ink at the tip of the ink discharge port 6 by static electricity, when potential difference is generated between the inside electrode 8 and the outside electrode 9 by the signal source 13. Therefore, the distance between the outside electrode 9 and the discharge port 6 is shorten to a several mm. tenths, and the potential difference between the inside electrode 8 and the outside electrode 9 can be reduced to a several handred volts, and a miniaturizing of the signal source and the promotion of a safety can be achieved. And it is also possible to narrow a distance between nozzles, and to manufacture as a multinozzle head.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inkjet recording apparatus that uses electrostatic force to eject ink droplets.

Structure of a conventional example and its problems FIG. 1 shows an example of a conventional inkjet recording apparatus that utilizes electrostatic force. Nozzle 1 filled with ink
When a potential difference is provided between the signal source 3 and the counter electrode 2, the ink in the nozzle 1 becomes an ink droplet 6 and flies toward the counter electrode 2 due to the electrostatic force generated by the potential difference. Characters, figures, etc. are formed on the recording paper 4 placed on the front side.

To describe the principle of ink ejection in detail, for example, when a positive potential is applied to nozzle 1, negative charges are concentrated on the ink meniscus generated at the tip of nozzle 1, and this negative charge is transferred to the opposite electrode. Because it is attracted by the positive potential of 2,
The ink in the nozzle 1 becomes a negatively charged ink droplet 5
It flies next to me.

However, in general, the mass of the ink droplet 6 is very large in proportion to the electrons, etc., and the distance between the tip of the nozzle 1 and the counter electrode 2 is maintained at a certain distance for practical purposes, and is at least one group or more. is necessary, so it is necessary to make the potential difference between the ink inside the nozzle 1 and the counter electrode 2 very large, and usually 1 to
It is customary to provide a potential difference of several kilovolts. Therefore, especially when attempting to increase density by providing multiple nozzles, there are disadvantages such as an increase in the size of the signal power source and a decrease in safety, and it is not suitable for colorization or miniaturization of products as printers. There was a problem.

Purpose of the Invention It is an object of the present invention to provide an inkjet recording device that eliminates the above-mentioned drawbacks, utilizes electrostatic force, has a small potential difference, has good responsiveness, and is easily adaptable to multiple nozzles. .

Structure of the Invention In order to achieve the above object, the present invention forms an internal electrode in a part of an ink chamber adjacent to an ink discharge port of an ink nozzle that contacts ink, and an external electrode is formed on the same plane as the front surface of the ink discharge port or at a position behind this. This is an inkjet recording device in which electrodes are provided and a potential difference is applied between an internal electrode and an external electrode.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a first embodiment showing the basic configuration of the present invention. Reference numeral 20 denotes an ink nozzle, which has an ink ejection port 6 at the ψ:Ili portion of the ink chamber 7, and an internal electrode 8 at a portion of the ink chamber 7 that contacts the ink.

The external electrode 9 is provided on the same side of the recording paper 1Q as the ink ejection port 6, and the external electrode 9 is positioned so that the electrode front surface 11 is on the same surface as the nozzle front surface 12 or slightly rearward. The signal source 13 connects the inner ', IL pole 8 and outer electrode 9
When a potential difference is created between the
and flies onto the recording paper 1o. A feature of the present invention is that the ink droplets 14 can be ejected even if the external electrode 9 is located on the same plane as the ink ejection port 6 or slightly behind the ink ejection port 6. Due to this configuration, the distance between the external electrode 9 and the ink ejection port 6 can be shortened to 10 minutes, and the potential difference between the internal electrode 8 and the external electrode 9 can be reduced to several hundred volts. , the signal power source 13 can be made smaller, and safety can be improved.

FIG. 3 is another embodiment of the invention. The same parts as in Figure 2 are indicated with the same symbols. Air nozzles 21 are provided around the ink nozzles 20.

Air flow 16 through a pressure source (not shown) such as an air pump
An air nozzle 21 provided around the external electrode 9 generates
Air flow 16 is allowed to flow out through opening 15 of. A pressure gradient due to the air flow spreads in the space in front of the ink discharge port 6. This pressure gradient and the electrostatic force due to the potential difference between the internal electrode 8 and the external electrode 9 act together, causing the ink droplet to
The formation of the ink droplet becomes easier and the ink droplet 1 is formed with a small potential difference.
4 can occur.

FIG. 4 shows a third embodiment of the invention. The same parts as in Figure 3 are indicated with the same symbols. An air flow 16 is generated from a pressure source (not shown), such as an air pump, and is connected to an air nozzle 2.
An air flow 16 exits from the opening 15 of 1 . A pressure gradient due to the air flow spreads in the space in front of the ink discharge port 6. The external electrode 9 is arranged outside the opening 15 of the air nozzle 21. The pressure gradient caused by the air flow and the electrostatic force caused by the internal electric potential (the potential difference between the water 8 and the external electrode 9) act together to form ink droplets in the same way.

The position 14 of the external electrode 9 is effective in preventing ink dripping from the ink discharge port 6 from reaching the external chamber (; plate 9) and causing electrical troubles such as short circuits through the opening 15. It has the advantage that the signal line can be taken out in one piece, making the head manufacturing easier.As a matter of course, compared to the embodiment shown in Fig. 2, which has no air flow, the potential difference is smaller. This enables the generation of ink droplets.

1. As is clear from the examples shown in FIGS. 2 to 4,
The nozzle spacing can be made extremely close, /l
:Effects of the invention of a multi-nozzle head that self-tacks on lightning suction As described above, the present invention forms an internal electrode in the part of the ink chamber adjacent to the ink discharge port that contacts the ink, and forms the internal electrode on the same side as the front surface of the ink discharge port. In an inkjet recording device, an external electrode is provided on the surface or at a position behind this, and a potential difference is applied between the internal electrode and the external electrode.The internal electrode and the external electrical connection can be provided very close to each other, so the potential difference is (driving voltage) is lower, miniaturization of the signal power supply and improvement in safety are achieved. In addition, the nozzle spacing can be narrowed, and it can also be manufactured as a multi-nozzle head.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing an example of a conventional inkjet recording device, FIG. 2 is a cross-sectional side view showing the structure of an embodiment of the inkjet recording device according to the present invention, and FIGS.
Each figure is a cross-sectional side view showing the structure of another embodiment of the inkjet recording apparatus according to the present invention. 6...Ink discharge port, 8...Internal electrode, 9...External electrode, 12...Nozzle front, 13...Signal power supply , 14... Ink droplet, 16... Opening, 16... Air flow. Name of agent: Patent attorney Toshio Nakao? 1 or 1 person @
Figure 1 Figure 3 Figure 4

Claims (3)

[Claims] (1) An ink ejection port is provided at one end of the ink chamber of the ink nozzle, and an internal electrode in contact with the ink in the ink chamber is located on the nozzle side with respect to the object to be recorded and is on the same plane as compared to the front surface of the nozzle. Alternatively, an inkjet recording apparatus is characterized in that a potential difference is applied between the inkjet ink and an external electrode provided at the rear, and ink is ejected from an ink ejection port and stopped by this potential difference to perform printing. (2) The inkjet recording apparatus according to claim 1, characterized in that an external electrode is provided on the outer periphery of the nozzle opening. (3) The inkjet recording apparatus according to claim 1, wherein an air flow is caused to flow from around the nozzle.