JPS59106971A - Ink jet printing head - Google Patents

Abstract

PURPOSE:To provide the titled printing head good in energy efficiency, generating almost no sound and prevented from the undesired injection of ink, constituted by providing a vibration generator for generating pressure for injecting the ink in an ink communication part. CONSTITUTION:A vibration generator 13 acting as a vibrator is arranged in a pressure chamber 11 and, for example, constituted of a bimorph type electrostriction element. Therefore, when voltage is applied to the vibration generator 13, the vibration generator 13 is curved and an ink droplet 15 is injected from an orifice 12 by this action. When the vibration generator 13 is curved, negative pressure is generated in the tank side thereof and the ink is sucked in the pressure chamber 11 while the ink flow is stopped when pressure is balanced. In this case, when the interval of the vibration generator 13 and the wall of the pressure chamber 11 is made narrow, the vibration resistance of the ink stream can be made large and vibration can be rapidly attenuated. Because the vibration generator is present in the ink, vibration can be extremely reduced.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an ink jet print head that ejects ink droplets to form dots of ink on a paper surface to print an image pattern.

Prior Art and Problems When printing data processing results on paper using a data processing device, there are dot printers that use dot wires to form dots on the paper surface. It requires a large driving force to drive up to 100 degrees, and there are also problems such as the generation of impact noise. Therefore, inkjet print heads that do not require such a large driving force and generate little noise during printing are used in output devices of data processing apparatuses.

A conventional inkjet print head includes a tank 1 in which ink is stored and a plurality of pressure chambers 2, as shown in FIG.
(only one is shown in FIG. 1), and an orifice 3 is arranged at the tip of the pressure chamber 2, and each of the plurality of pressure chambers 2 communicates with the tank 1 through a communication pipe section. By selectively deforming a plurality of pressure chambers 2, ink droplets 4 are ejected from an orifice 6 communicating with the pressure chambers 2 to form ink dots 9 on a sheet of paper (not shown).

In this case, as shown by the arrow in FIG. 1, when pressure is applied to the pressure chamber 2, the clay wall portion of the pressure chamber 2 bends inward as shown by the dotted line, so the volume of the pressure chamber 2 decreases. In response to this, ink droplets 4 are ejected from the orifice 3. As a means for applying pressure, a pressure chamber 2 is used as shown in FIG.
An electrostrictive element 5 is arranged in correspondence with each pressure chamber on the earthen wall portion 2-1.

By selectively applying a voltage to the electrostrictive element 5, the electrostrictive element 5 is deformed, thereby deforming the thin metal earth wall portion as shown by the dotted line in FIG. has been done.

As another example, as shown in FIG. 3, an ink vibro communicating with a tank is surrounded by an electrostrictive element 7, and by applying a voltage thereto, the ink vibro is partially contracted, and from the orifice 8 part. Eject ink droplets.

In either case, the OriSwiss and tank are in direct communication, and there is no pump or pulp, and equilibrium is maintained by the surface tension of the ink at the tip of the orifice.

Equilibrium is maintained such that ink does not flow out and air does not enter the interior.

Therefore, with this method, as shown by the dotted line in Figure 1, a large amount of energy is required to push and deform the pressure chamber 2, and the pressure causes the ink to return not only to the orifice side but also to the tank 1 side. , energy efficiency is not good. Moreover, since the pressure chamber is deformed and vibrated from outside, sound leaks to the outside. The ink that has returned to the tank 1 then returns to the pressure chamber 2 side again, causing vibration of the ink. Therefore, the ink surface at the tip of the orifice is not stable and a second ink droplet may be ejected, making high-speed printing difficult.

OBJECTS OF THE INVENTION It is an object of the present invention to improve the above-mentioned drawbacks and to provide an energy-efficient and almost no-sound generating device.

An object of the present invention is to provide an inkjet print head that prevents undesired jetting of ink.

Structure of the Invention To achieve the above object, the inkjet printhead of the present invention includes a tank portion, an inkjet orifice, and an inkjet means for generating pressure to eject ink droplets from the inkjet orifice. An oscillator that generates pressure for ink ejection is provided in an ink communication portion between the tank portion and the ink ejection orifice.

The present invention is characterized in that the ejection of ink droplets from the p-ink ejection orifice is controlled by driving and controlling this oscillator.

Embodiment of the Invention An embodiment of the present invention will be described with reference to FIGS. 4 and 5.

FIG. 4 is a block diagram of a main part of an embodiment of the present invention, and FIG. 5 is an explanatory diagram of its operation.

In the figure, 10 is a tank, 11 is a pressure chamber, 12 is an orifice, 13 is an oscillator, 14 is a column, and 15 is an ink droplet.

In the present invention, an oscillating body 13 that acts as a vibrating body is arranged inside the pressure chamber 11. This oscillator 13 is.

Similar to the electrostrictive element 5 in FIG. 2, the electrostrictive element 9 is composed of, for example, an electrostrictive element manufactured by a bimorph shop. Therefore, when a voltage is applied to the oscillator 13, the oscillator 13 is bent as shown by the solid line in FIG. 5, and an ink droplet 15 is ejected from the orifice 12.

When the oscillator 13 bends, a negative pressure is generated on the tank side, and ink is sucked from the tank into the pressure chamber 11, and when the pressure is balanced, the flow of ink stops.

Therefore, unlike the conventional method which applies positive pressure to the tank chamber, it is very efficient. Moreover, when the oscillator 13 is restored to the state shown by the dotted line in FIG. 5, since it is inside the ink, there is less resistance when it returns, and the oscillator 13 returns slowly, making it possible to suppress ink vibration. At this time, the oscillating body 13 and the pressure chamber 11
If the distance between the walls is narrowed, the vibration resistance of the ink flow can be increased, and the vibrations can be quickly damped. In conventional devices, if the communication tube is made thinner to suppress vibrations, the supply of ink to create ink droplets is restricted.
The particle formation frequency cannot be increased, and the printing speed will be suppressed.

Since the oscillator 13 is inside the ink, the vibration noise is attenuated and can be made very small. Also.

In the conventional type, the outer wall of the pressure chamber has two walls, as shown in Figure 2.
As shown in -1, a thin metal plate is commonly used, and as a result, it is susceptible to mutual interference due to the vibration of the electrostrictive element 5. However, since an oscillator is placed individually in each pressure chamber,
There will be no mutual interference. Moreover, there is no need to curve the outer wall.

This can be constructed with a thick material, and mutual interference and vibration noise can be further suppressed.

In addition to placing the oscillator 13 in the pressure chamber as shown, it is coated with glass, and a portion of the pressure chamber is made of a material such as rubber that allows the oscillator to be inserted. It can also be configured as

The oscillating body is not limited to electrostrictive elements but other vibrating bodies.

For example, a magnetostrictive element or the like can also be used. Furthermore, if the oscillator itself excites vibration, then l''!: Not limited.

A similar effect can be obtained even if vibrations are excited from other external oscillators. The oscillator does not necessarily have to face the orifice, but the direction of the oscillator is not limited as long as the channel structure has the effect of propagating waves to the orifice.

Another embodiment of the invention will be described in FIG.

In the example of FIG. 6, the oscillator 16 arranged in the pressure chamber 17
is shaped so that the ink can easily flow in the direction of the orimeter 18 and difficult to flow in the opposite direction. For example, if the oscillating body 16 is made into a hemispherical shape and its spherical part is placed on the tank 19 side, when the oscillating body 16 vibrates inflectionally in the direction of the orifice 18, the ink flow will be strongly pushed out in the direction of the orifice. However, when it returns, the two spherical surfaces come to face the flow path, and the fluid resistance becomes smaller than when the ink is ejected, resulting in a smooth recovery without generating a large negative pressure on the orifice side. Therefore, it is possible to effectively prevent malfunction due to air being sucked in from the oriice, and it is also possible to increase the speed of printing by smoothing the flow of ink.

Of course, the shape of the oscillator is not limited to a hemispherical shape,
Other shapes 9 may also be used, such as a mortar shape or a conical shape.

Effects of the Invention According to the present invention, it is possible to construct an inkjet print head that can eject ink droplets efficiently and at high speed with a relatively simple configuration, and also to reduce vibration noise and quickly converge the ink.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a conventional inkjet print head, FIG. 6 is an example of another configuration of a conventional inkjet print head, FIG. 4 is a configuration diagram of an embodiment of the present invention, and FIG. The operation explanatory diagram, FIG. 6, is another embodiment of the present invention. In the figure, 1 is a tank, 2 is a pressure chamber, 3 is an orifice, 4 is an ink droplet, 5 is an electrostrictive element, and 10 is a tank. 11 is a pressure chamber, 12 is an orifice, and 13 is an oscillator. 14 is a support, 15 is an ink droplet, and 16 is an oscillator. 17 is a pressure chamber, 18 is an orifice, and 19 is a tank. Patent applicant Fujitsu Ltd. Representative Patent Attorney Akira Yamatani

Claims (2)

[Claims] (1) In an inkjet print head having a tank portion, an ink ejection orifice, and an ink ejection means that generates pressure to eject ink droplets from the ink ejection orifice, in an ink communication portion between the tank portion and the ink ejection orifice. 1. An inkjet print head comprising: an oscillator that generates pressure for ejecting ink; and by driving and controlling the oscillator, the ejection of ink droplets from an ink ejection orifice is controlled. (2) The inkjet print head according to claim 1, wherein the oscillator is configured to have different fluid resistance when it is displaced toward the oriice side and when it is displaced toward the tank section.