JPH0976494A - Ink jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the pressure wave generating in an ink chamber communicating with a nozzle, through which a liquid drop is discharged, from exerting influence upon other ink chambers. SOLUTION: Pressure wave, which is generated by the change of the volume of an ink chamber 4 through the deformation of a side wall 5, arrives a nozzle 50, resulting in discharging a liquid drop. And, since pressure wave, which is generated similarly and proceeds toward a common ink chamber 46 side, is absorbed by the airs retained in a water-repellent porous body 30, no presser wave spreads through the common ink chamber 46 to other ink chambers 4. Thus, even when ink is simultaneously discharged through a large number of the nozzles 50 in an ink jet device produced as mentioned above, the discharge speeds of ink liquid drops do not change from one another, resulting in allowing to carry out high quality recording.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet device, and more particularly to a drop-on-demand type multi-nozzle inkjet head device.

[0002]

2. Description of the Related Art In recent years, piezoelectric ink jet heads have been proposed. These heads are provided with a plurality of ink chambers filled with ink, and the volume of the ink chamber is changed by the dimensional displacement of the piezoelectric actuator to generate a pressure wave. The ink is ejected and the ink is introduced into the ink chamber when the volume is increased. Then, by ejecting ink from the ink chamber at a predetermined position, it is possible to form a desired character or image.

Such an ink jet head will be specifically described with reference to a perspective view of the ink jet head 1 shown in FIG. 2 and a partial sectional view of the ink jet head 1 shown in FIG.

By joining the piezoelectric ceramic plate 2 having a plurality of side walls 5 and polarized in the direction of the arrow 28 and the lid 6 to each other, a large number of parallels are formed which are spaced from each other in the lateral direction in FIG. The ink chamber 4 is configured. The ink chamber 4 has a rectangular cross section that is long and narrow, and the side wall 5 extends over the entire length of the ink chamber 4 and can be deformed perpendicularly to the central axis of the ink chamber 4. Therefore, the deformation of the side wall 5 changes the volume of the ink chamber 4 and changes the ink pressure in the ink chamber 4. A drive electrode 7 for applying a drive electric field is formed in a region of the lower half (or upper half) of the surface of the side wall 5, and the surface of the drive electrode 7 serves to insulate the ink from the drive electrode 7. Insulated. At one end of the piezoelectric ceramics plate 2 and the lid 6, a nozzle plate 60 having a nozzle 50 communicating with one end of each ink chamber 4 is provided with an adhesive 70.
Has been fixed by.

When, for example, the ink chamber 4B is selected in accordance with predetermined print data in the ink jet head 1, a driving electric field 10 is applied between the driving electrodes 7C and 7D and the driving electrodes 7E and 7F by a driving device (not shown). It At this time, since the driving electric field direction and the polarization direction are orthogonal to each other, the side walls 5B and 5C are deformed in a V shape toward the outside of the ink chamber 4B due to the piezoelectric thickness sliding effect. At this time, ink is supplied into the ink chamber 4B. After that, when the application of the driving electric field 10 is cut off, the side walls 5B and 5C return to their original positions. Due to this deformation, the ink pressure in the ink chamber 4B becomes a positive pressure, and ink droplets are ejected from the nozzle 50 corresponding to the ink chamber 4B. After that, the nozzle plate 6
0 is fixed to one end surfaces of the piezoelectric ceramic plate 2 and the lid 6 with an adhesive 70.

[0006]

However, in the conventional ink jet head 1 described above, the pressure wave generated by the volume change in the ink chamber 4B propagates to the ink supply path common to the ink chambers 4 and the above-mentioned again. Ink chamber 4B
Since the vibrations propagate to the nozzles 50 through the other ink chambers 4A and 4C and become vibrations that are the discharge energy of the liquid droplets, the vibrations become extra vibrations, which hinders stable discharge of the liquid droplets from the nozzles 50. was there.

In order to correct this problem, if the distance between the ink chambers 4 is increased so that the extra vibration is less likely to propagate to the other ink chambers 4A and 4B, there is a problem that the head becomes large. It was

The present invention has been made to solve the above-mentioned problems, and prevents the influence of extra pressure waves on other ink chambers due to the propagation of pressure waves generated from the ink chambers, and stabilizes the liquid droplets. It is an object of the present invention to provide an ink jet device capable of discharging the ink.

[0009]

In order to achieve this object, in a first aspect of the present invention, a plurality of nozzles for ejecting ink and a plurality of ink chambers communicating with the nozzles and filled with ink are provided. In an ink jet device in which a manifold member having a common ink chamber that communicates with each ink chamber is joined to an actuator member that is provided, ink droplet ejection is achieved by providing a water repellent porous member provided in the common ink chamber. Therefore, the pressure wave generated in the ink chamber is absorbed by the damper effect of the air held in the water-repellent porous member and is not propagated to other ink chambers. Further, the water-repellent porous body retains air even if the ink has a low surface tension.

Further, in the ink jet apparatus according to the present invention, the volume of the ink chamber is changed by the actuating portion of the actuator member, and the pressure wave generated in the ink chamber for ejecting the ink droplet is repelled. It is absorbed by the damper effect of the air held by the porous member having water content, and is not propagated to other ink chambers.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. However, the same members as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 is a sectional view showing an ink jet device of the present invention. A plurality of ink chambers 4 are formed by joining the piezoelectric ceramic plate 2 (FIG. 2) having a plurality of side walls 5 and the lid 6 (FIG. 2). At one end of the piezoelectric ceramic plate 2 and the lid 6, a nozzle plate 60 having a nozzle 50 communicating with one end of each ink chamber 4 is provided with an adhesive 70 (FIG. 2).
Has been fixed by. A manifold member 40 that supplies ink from an ink cartridge (not shown) is fixed to the other end by an adhesive. A common ink chamber 46 communicating with each ink chamber 4 is formed in the manifold member 40. Inside the common ink chamber 46, a porous body 30 having water repellency is provided at a position corresponding to each side wall 5.

Here, the porous body 30 having water repellency is
For example, a Teflon (PTFE resin) porous body can be used. In this example, a material (trade name: Gore-tex Japan Gore-tex Co., Ltd.) made of a Teflon porous body was used. Alternatively, a porous body having no water repellency that has been subjected to a surface treatment for imparting water repellency or the like may be used. In this case, for example, it is preferable to coat with a member containing a polymer having a fluorine-containing heterocyclic structure in the main chain. Examples of such a coating material include Cytop (Asahi Glass Co., Ltd.) and Teflon AF (DuPont).

The volume of the ink chamber 4 changes due to the deformation of the side wall 5, and the pressure wave generated thereby reaches the nozzle 50 to eject a droplet. Further, similarly generated pressure waves toward the common ink chamber 46 side of the manifold member 40 are absorbed by the air 31 held by the porous body 30 having water repellency, so that another ink passes through the common ink chamber 46. It does not propagate to chamber 4.

Even when the ink-jet apparatus of this embodiment thus manufactured was used to eject ink from a large number of nozzles 50 at the same time, the ejection speed of ink droplets did not change. Therefore, high quality recording can be performed.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in the present embodiment, the present invention is used in an inkjet device that ejects ink droplets by shear mode deformation of the piezoelectric element, but it may be used in an inkjet device that ejects ink droplets by direct mode deformation of the piezoelectric element. The present invention may be used. Further, the present invention may be applied to a known thermal jet type inkjet device.

[0017]

As is apparent from the above description, according to the ink jet apparatus of the first aspect, the ink droplet ejection is performed by including the water repellent porous member provided in the common ink chamber. Since the pressure wave generated in the ink chamber is absorbed by the damper effect of the air held in the porous member having water repellency and does not propagate to other ink chambers, stable droplet ejection is possible. Further, it is not necessary to increase the distance between the ink chambers so that the extra vibration does not easily propagate to the other ink chambers, unlike the conventional ink jet device, and thus the size can be reduced. Further, since the porous body has water repellency, even in an ink jet device using an ink having a low surface tension, the air retention property is extremely good, so that stable droplet ejection sustainability is good.

Further, according to the ink jet apparatus of the second aspect, the pressure wave generated in the ink chamber for ejecting ink droplets by changing the volume of the ink chamber by the actuating portion of the actuator member, It is absorbed by the damper effect of the air held in the water-repellent porous member, does not propagate to other ink chambers, and can stably discharge droplets. Since it is not necessary to increase the distance between the ink chambers so that the vibration does not easily propagate to other ink chambers, the size can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an inkjet device of the present invention.

FIG. 2 is a perspective view showing an inkjet device according to the related art and the present invention.

FIG. 3 is an explanatory diagram showing an operation of a conventional ink jet device and the present invention.

[Explanation of symbols]

 4 Ink Chamber 5 Side Wall 30 Porous Body 31 Air 50 Nozzle 40 Manifold Member 46 Common Ink Chamber

Claims (2)

[Claims] 1. An actuator member having a plurality of nozzles for ejecting ink and a plurality of ink chambers communicating with the nozzles and filled with ink, and a common ink chamber communicating with each ink chamber. An ink jet device in which a manifold member is joined, characterized by comprising a water repellent porous member provided in the common ink chamber. 2. The ink jet apparatus according to claim 1, wherein the actuator member includes an operating portion that changes the volume of the ink chamber to eject ink.