JPH08252912A - Ink jet head - Google Patents

Abstract

PURPOSE: To easily assemble piezoelectric elements applying pressure to pressure chambers and nozzles ejecting ink droplets by applied pressure inclusive of the positioning of them in an ink jet head even in the case of a multinozzle head. CONSTITUTION: Grooves 13 for fitting a plurality of piezoelectric elements 2b being integrated pressure applying members are formed to a pressure chamber base 31b for forming pressure chambers and a nozzle member 6b having the nozzles 5b corresponding to the piezoelectric elements 2b is supported on the front of the base 31b and the space parts formed by the grooves 13 between the piezoelectric elements 2b and the nozzle member are formed as pressure chambers to constitute an ink jet head. Since the piezoelectric elements 2b and the nozzle member 6b are combined to be supported on the pressure chamber base 31b forming the pressure chambers, the assembling of the respective members containing the pressure chambers inclusive of the positioning of them becomes easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head in an inkjet recording apparatus, and more particularly to improvement of an ink-on-demand type inkjet head.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view schematically illustrating an example of a conventional ink-on-demand type ink jet head. In this figure, the left end of the rod-shaped piezoelectric body 2 is fixed to the left end of the support block 1. A pressure chamber block 3 is fixed to the right end of the support block 1. The pressure chamber block 3 includes a pressure chamber 4, and the right end of the rod-shaped piezoelectric body 2 is inserted from the left end of the pressure chamber 4 in a liquid-tight and slidable manner. The right end of the pressure chamber 4 is closed by a nozzle plate including a nozzle 5.

An ink supply hole 7 for supplying ink from an ink source (not shown) communicates with the pressure chamber 4. The rod-shaped piezoelectric body 2 is provided with a pair of electrodes 8, which are connected to a recording signal voltage source Vs. In the ink jet head configured as described above, one set of electrodes 8 from the recording signal voltage source Vs is used.
When a recording signal is applied to the rod-shaped piezoelectric body 2, the rod-shaped piezoelectric body 2 extends a little due to the lateral effect. Therefore, ink droplets in the pressure chamber 4 are ejected from the rod-shaped piezoelectric body 2.

[0004]

In the conventional ink jet head shown in FIG. 4, the support block 1 for supporting the pressure chamber block 3 having the pressure chamber 4 and the piezoelectric body 2 is provided.
Since it is necessary to position the piezoelectric body 2 and the pressure chamber block 3 etc. on the support block 1 in the assembly in order to separately provide them, not only the alignment becomes troublesome but also the assembly becomes very troublesome. Was there.

In addition, as the ink jet head, when a large number of nozzles 5 are arranged in parallel, each nozzle 5
Therefore, the pressure chamber 4 is required, and the piezoelectric body 2 is also required to be provided. Therefore, in the case of a multi-nozzle head having a large number of nozzles 5, it is difficult to reduce the size. Moreover, in order to reduce the size, it is necessary to make the piezoelectric body 2 thin or small, and it is important to surely support the piezoelectric body on the support block. That is, since the piezoelectric body 2 becomes thin, it may be damaged during driving or may be damaged during assembly unless the support is performed reliably.

In view of the above-mentioned problems, the present invention provides an ink jet head having a structure that facilitates the assembly of the ink jet head and can prevent the pressure applying member applied to the pressure chamber from being damaged during assembly. is there.

[0007]

An ink jet head for achieving the above object according to the present invention is one in which pressure is applied to a pressure chamber and ink in the pressure chamber is ejected from a nozzle, the pressure chamber being formed. It is characterized in that a member for applying pressure and a nozzle member having the above-mentioned nozzle are combined and supported on a pressure chamber base for carrying out.

In such a structure, since the nozzle member and the member for applying pressure, for example, the piezoelectric body are also supported by the pressure chamber base, the alignment on the same member is simplified and the assembly is facilitated. . Particularly in the case of a multi-nozzle head, assembly including positioning becomes easy.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a view showing the structure of an inkjet head according to the first embodiment of the present invention.
FIG. 1A is a cross-sectional view schematically showing the inkjet head, and FIG. 1B is a partially enlarged view.

The structure of the ink jet head according to the present invention will be described with reference to these drawings. The elongated rod-shaped piezoelectric body 2a is provided in the groove of the pressure chamber base 31a and is a member for applying pressure. The left end of a certain rod-shaped piezoelectric body 2a is fixed to the left end of the pressure chamber base 31a. The rod-shaped piezoelectric body 2a is provided with a pair of electrodes 8a, and the piezoelectric body and the electrodes are covered with a seal film 9.

A nozzle member 6a including a nozzle 5a is fixed to the right end of the pressure chamber base 31a. The pressure chamber 4 is provided between the right end of the rod-shaped piezoelectric body 2a and the nozzle member 6a.
a is formed, and the pressure chamber base 31a is covered by the pressure chamber cover plate 32a.

Ink supply holes 7a for supplying ink to the pressure chambers 4a are formed in the pressure chamber cover plate 32a. An ink tube fixing plate 33a for fixing the ink tube 10 is further fixed on the pressure chamber cover plate 32a. The ink tube 10 guides ink from an ink source (not shown) to the ink supply hole.

The seal film 9 improves the liquid tightness of the pressure chamber 4a and the slidability of the rod-shaped piezoelectric body 2a. Further, when the pressure chamber base 31a and the pressure chamber cover plate 32a are made of a metal material, the seal film 9 has the pressure chamber components 31a and 32a and the electrode 8a.
Acts as an insulating material between and.

It will be understood that the ink jet head thus constructed can operate similarly to the conventional ink jet head shown in FIG. Therefore, in FIG.
In the ink jet head having the structure shown in (A),
Groove of pressure chamber base 31a and pressure chamber cover plate 32a
In the elongated space formed by the rod-shaped piezoelectric body 2
The pressure chamber base 31a is supported so that most of the length of "a" is included. Therefore, the rod-shaped piezoelectric body 2a
Is held in the space and mechanically protected, and can be made much thinner than the conventional rod-shaped piezoelectric body 2.

As a result, the ink jet head of FIG. 1A can be made smaller than the conventional ink jet head. In particular, when a multi-nozzle is constructed by using an inkjet head as shown in FIG. 1A, the effect of downsizing becomes more remarkable.

Assuming now that FIG. 1A shows a cross section of such a multi-nozzle head, FIG. 1C shows a cross section along line 1C-1C in FIG. 1A. Shows a part of. That is, when a multi-nozzle head is configured, since a plurality of rod-shaped piezoelectric bodies 2a are arranged in parallel, even if the thickness of each rod-shaped piezoelectric body is slightly reduced, the size of the multi-nozzle head is reduced as a whole. It can be understood that it can greatly contribute to

In addition, as shown in FIG. 1, the rod-shaped piezoelectric body 2a
Including the nozzle member 6a in which the nozzle 5a is formed,
It is supported and fixed on the pressure chamber base 31a. Therefore, the pressure chamber 4a and the piezoelectric body 2 are associated with a plurality of nozzles.
It will be understood that since a, the nozzle member 6a, etc. are provided on the pressure chamber base 31a, the positioning and the like at that time are determined by the same member of the pressure chamber base 31a, so that the work of assembling them is very simple.

FIG. 2 is an exploded perspective view showing another embodiment of the present invention for further simplifying the assembly in the multi-nozzle head. In this multi-nozzle head, a pressure chamber base 31b having a plurality of elongated grooves 13
As shown in the figure, a comb-shaped piezoelectric body 2b including a plurality of elongated branches is fitted on the upper side of the lower spacer 11a. Each branch of the comb-shaped piezoelectric body 2b has a pair of electrodes 8 on the front and back.
b is provided. The front end of the groove 13 of the pressure chamber base 31b is closed by a nozzle member 6b having a plurality of nozzles 5b. That is, the nozzle member 6a is supported by the pressure chamber base 31b together with the comb-shaped piezoelectric body 2b.

As a result, a plurality of spaces formed between the tips of the branches of the comb-shaped piezoelectric body 2b and the nozzle member 6b are formed as pressure chambers. A plurality of ink supply holes 7b for supplying ink to the plurality of pressure chambers are correspondingly formed in the pressure chamber cover plate 32b provided on the piezoelectric body 2b via the upper spacer 11b. An ink tube fixing plate 33b is further fixed on the pressure chamber cover plate 32b. The ink tube fixing plate 33b is formed with a plurality of ink tube fixing holes 14 corresponding to the plurality of ink supply holes 7b.

In the multi-nozzle head configured as described above, by applying a recording signal voltage to a selected set of the plurality of sets of electrodes 8b, ink droplets can be ejected from the corresponding nozzle 5b. Be understood. In the multi-nozzle head of FIG.
As shown in the figure, the comb-shaped piezoelectric body 2b having a plurality of slender branches is fitted into the pressure chamber base 31b of the one body having the plurality of three, so that individual inkjet heads are assembled to form the multi-nozzle. It will be appreciated that it is much easier to assemble as compared to a conventional multi-nozzle head based.

Further, the multi-nozzle head of FIG. 2 can make the ejection characteristics among the nozzles uniform as compared with the conventional multi-nozzle head in which individual ink jets are assembled.

Here, as shown in FIG. 2, in the multi-nozzle head, the comb-shaped piezoelectric body 2b is fitted in the groove 12 in the pressure chamber base 31b through the spacers 11a and 11b from above and below to support the nozzle member 6b. Then, the pressure chamber cover plate 32b is covered and fixed from the upper side to be assembled. Therefore, not only the assembly is very simple, but also the piezoelectric members 2b are arranged in the nozzle member 6 during the assembly.
It can be easily incorporated including the positioning of b. This uses the pressure chamber base 31b as a substrate and the pressure chamber 4a.
This is because the piezoelectric body 2b and the nozzle 5b corresponding thereto are supported.

FIG. 3 is a perspective view showing another embodiment of the comb-shaped piezoelectric body used in the multi-nozzle head according to the present invention. The comb-shaped piezoelectric body 2c of FIG. 3 is similar to the comb-shaped piezoelectric body 2b of FIG. 2, but the comb-shaped piezoelectric body 2c of FIG.
An integrated circuit 12 is provided. The integrated circuit 12 includes a driver circuit for generating a recording signal voltage to be applied to the electrodes 8c provided on each of the elongated branches of the piezoelectric body. By doing so, it is possible to significantly reduce the number of wires to the piezoelectric body in the multi-nozzle head.

[0024]

As described above, according to the ink jet head of the present invention, the pressure chamber base for forming the pressure chamber and the like is configured to support the pressure applying member and the nozzle member having the nozzle. As a result, the assembly of the head is very easy.

Particularly in the case of a multi-nozzle head, the positioning and assembly thereof are greatly simplified by providing the regions for supporting the pressure chamber base individually.

[Brief description of drawings]

FIG. 1 is a sectional view showing an internal structure of an inkjet head according to the present invention, (A) is an overall sectional view of the inkjet head in an ink droplet ejection direction, and (B) is an enlarged sectional view showing an ink pressure chamber portion. , (C) are sectional views taken along line 1C-1C in (A).

FIG. 2 is an exploded perspective view showing a configuration of another inkjet head according to the present invention in an assembled state.

FIG. 3 is a schematic perspective view showing another embodiment of the comb-shaped piezoelectric body in the multi-nozzle head of the present invention.

FIG. 4 is a sectional view schematically showing a conventional inkjet head.

[Explanation of symbols]

 2a (2b, 2c) Piezoelectric body 4a Pressure chamber 5a (5b) Nozzle 6a (6b) Nozzle member 13 Groove 31a (31b) Pressure chamber base 32a (32b) Pressure chamber cover plate

Claims (1)

[Claims] 1. An ink jet head for applying pressure to a pressure chamber and ejecting ink in the pressure chamber from nozzles, wherein a member for applying pressure to a pressure chamber base for forming the pressure chamber, An inkjet head configured to support together with a nozzle member having the above nozzle.