JPH0351136A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To increase the use efficiency of an electric field and reduce a voltage applied to an electrode by charging ink in an ink feed path and generating an electric field for ink discharge control at an electrode for ink discharge control provided near an ink nozzle. CONSTITUTION:Ink is negatively charged by supplying a negative charge to the ink using an ink charging electrode 12 in an initial state. The ink charged by the ink charging electrode 12 runs in an ink discharge outlet direction, reaching a position near an ink discharge control electrode 13. No potential difference is present between the ink discharge control electrodes 13, 14 during ink discharge, and the charged ink 11 is discharged from an ink nozzle 10 without receiving an electric resistance by shifting the electrodes by a potential equal to an ink charging potential. When ink discharge is controlled, a potential difference is provided between the ink discharge control electrodes 13, 14 so that the electrode 13 becomes negative and the electrode 14 becomes positive.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inkjet recording apparatus that controls ink ejection using electrostatic force.

Conventional technology Conventionally, as an inkjet recording method using electrostatic force,
For example, an ink ejection method as described in Japanese Unexamined Patent Publication No. 56-8268 is known.

This method charges the ink by placing an electrode inside the ink.
Ink is drawn out and recorded using a back electrode placed on the back of the recording paper.

Problems to be Solved by the Invention In the above recording method, due to the long distance between the ink and the back electrode, it is necessary to apply a high voltage between the ink internal electrode and the back electrode in order to draw out the ink, which reduces the energy of the electric field. It was not used efficiently.

The present invention solves the above-mentioned drawbacks. Conventionally, there was a distance between the ink electrode and the back electrode, so the electric field was dispersed and required a high voltage. However, by efficiently concentrating the electric field, the voltage can be reduced. The purpose of the present invention is to provide a new type of inkjet recording device that makes it possible to achieve the following.

Means for Solving the Problems The present invention achieves the above object by charging ink within an ink supply path and generating an electric field for controlling ink discharge with an electrode for controlling ink discharge provided near an ink nozzle. It is.

Function: With the above-described structure, the present invention efficiently generates a force for controlling the ink ejection flow within the ink nozzle, and efficiently performs ink ejection.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

The figure is a sectional view of an ink nozzle in one embodiment of the present invention.

In the figure, 10 is an ink nozzle, 11 is ink, and 12 is an ink nozzle.
is an ink charging electrode, 13 is a first ink discharge control electrode,
14 is a second ink ejection control electrode.

The operation of the above configuration will be explained below.

The ink 11 in the ink nozzle 10 has an ink nozzle 10
A constant pressure P is applied from one side (the left side in the figure). There is no particular restriction on the method of applying this constant pressure P. This pressure causes ink to flow from one side of the ink nozzle 10 to the other at a constant flow rate.

In this initial state, the ink charging electrode 12 supplies a negative charge to the ink 11 to charge the ink negatively. The ink charged by the ink charging electrode 12 flows toward the ink discharge port, and the ink discharge control electrode 1
It reaches around 3. During ink ejection, there is no potential difference between the ink ejection control electrodes 13 and 14, and the charged ink 11 is shifted to the negative side by the same potential as the ink charging potential, so that the charged ink 11 is not subjected to electrical resistance and is moved toward the ink nozzle 1.
Discharge from 0. When controlling ink discharge, a potential difference is provided between the ink discharge control electrodes 13 and 14 so that the ink discharge control electrode 13 side is negative and the ink discharge control electrode 14 side is positive. Due to this potential difference, the charged ink 11 within the ink nozzle 10 receives a force in the opposite direction to the ink ejection direction, thereby preventing ink ejection.

If you want to completely stop ink ejection, you can give the charged ink a force that overcomes the pressure of the ink.

When the ink ejection control electrodes 13 and 14 are ring-shaped, the electric field strength is weakest on the center line of the ink nozzle 10 and becomes stronger toward the outer periphery. Therefore, when the ink 11 is not to be ejected, the force generated on the charged ink 1 by the electric field strength formed by the ink ejection control electrodes 13 and 14 is made to be a force greater than the pressure P on the ink nozzle center line. . As described above, the electric field strength is formed in the ink nozzle 10 so that it becomes stronger from the center to the outer circumference, so by decreasing the potential difference applied to the ink ejection control electrodes 13 and 14, the shutter It is possible to control the amount of ink ejected so that the opening is opened. Since the ink ejection control electrodes 13 and 14 are located near the ink nozzles, the electric field can be used efficiently. Ink ejection control electrode 13.
It is better to make the interval 14 as close as possible in order to use the electric field more efficiently. Further, it is better to make the ink nozzle diameter as small as possible in order to efficiently utilize the electric field, but since there is a trade-off with the ink ejection amount, it is necessary to balance the nozzle diameter and the pressure P.

In the figure, the ink is negatively charged, but it may also be positively charged. However, in that case, it is necessary to reverse the polarity of the ink ejection control electrodes 13 and 14.

In the figure, the ink ejection control electrode 111 and the electrode 13, ]/I are provided at two locations, but the ink charging electrode 12 may also serve as the ink ejection control electrode 13 and the electrodes may be provided at two locations.

Note that the ink nozzle 10, the ink 11. Ink charging electrode 12, first electrode 1 for generating electric field for controlling ink ejection
3. Second electrode 14 for generating an electric field for controlling ink ejection
The configuration is not limited to that shown in the figure, and the configuration is not limited as long as it has a similar effect, that is, generates an electric field to prevent ink flow.

By arranging two or more ink nozzles 10 as described above and applying a recording signal to each, a multi-nozzle inkjet head in which each ink nozzle 10 can independently eject ink 11 can be easily created.

Effects of the Invention According to this embodiment, the ink ejection control electrode is provided near the ink nozzle to form an electric field to prevent ink ejection, so the electric field is used efficiently and the voltage applied to the electrode is lowered. be able to. In addition, an inkjet recording head that can modulate the ink dot diameter and that can easily be configured with multiple nozzles can be produced.

[Brief explanation of drawings]

The figure is a sectional view showing one embodiment of the inkjet recording apparatus of the present invention. 10. Ink nozzle, 1 ink, 12... ink charging electrode, 13.14... ink ejection control electrode.

Claims (1)

[Claims] means for supplying a constant flow of ink to an ink nozzle; means for charging the ink; a pair of ink ejection control electrodes provided near the ink ejection opening of the ink nozzle; An inkjet recording apparatus characterized by comprising means for generating an electric field in a direction opposite to the direction in which ink flows.