JP3157269B2 - INK JET PRINT HEAD AND ELECTRONIC EQUIPMENT WITH THE SAME - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet print head and an electronic apparatus, such as a printer, a word processor, a facsimile, and a plotter, equipped with the ink jet print head.

[0002]

2. Description of the Related Art There is a Kaiser type ink jet print head mounted on various electronic devices such as a printer and a word processor. A Kaiser-type print head is generally shown in FIG.
(Plan view) and FIG. 7 (cross-sectional view along line BB in FIG. 6)
As shown in FIG. 5, an ink path plate 50 in which a large number of individual ink paths 51 are formed at regular intervals, and all the individual ink paths 5
1 is provided with a diaphragm (not shown for the sake of convenience) joined to the ink path plate 50 so as to cover the ink path 1, and a piezoelectric element 60 affixed to each part of the diaphragm located on the individual ink path 51. The individual ink path 51 includes a supply path 52, a pressure chamber 53, and a nozzle 5.
4, each piezoelectric element 60 (only one is shown) is located on the pressure chamber 53 of the individual ink path 51. In such a print head, an electric field is applied to the piezoelectric element 60 to displace the piezoelectric element 60, and the ink is pushed out from the nozzle 54 of the individual ink path 51 by moving the corresponding portion of the vibration plate with the displacement.

[0003]

In the above-mentioned Kaiser type print head, the ink path plate 50 and the vibration plate 70 are often joined by heating such as fusing, and as shown in FIG. A joint 80 is formed. However, in the joint portion 80, particularly in a portion where the supply passage 52 and the nozzle 54 of the individual ink passage 51 are arranged at equal intervals (see FIG. 6), the joint area between the ink passage plate 50 and the vibration plate 70 increases.

For this reason, for example, if the coefficient of thermal expansion of the ink path plate 50 is larger than that of the vibration plate 70, immediately after joining, as shown in FIG. Due to the difference in the coefficient of thermal expansion, the diaphragm 70 rises from the ink path plate 50 as shown in FIG. 9, and in a severe case, the diaphragm 70 may be broken. Also, if the bonding area between the ink path plate 50 and the vibration plate 70 is large, foreign matter is interposed on the bonding surfaces of the two, and poor bonding is likely to occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet print head which is free from defects such as floating or cracks at the joint surface between an ink path plate and a vibration plate, has a large joint strength and high reliability, and this print head. An electronic device including a head is provided.

[0006]

In order to achieve the above object, an ink jet print head according to the present invention comprises a conventional ink jet print head as described above.
The individual ink paths extend from the rear end of the ink
Narrow supply path, wide pressure chamber, and narrow nozzle
Ink path plate which is formed by
Between the narrow ink supply paths and the narrow
An island-shaped groove is formed between the spills and both ends.
Outside the individual ink path,
Thus, a groove extending from the rear end to the front end is formed, and the ink path plate and the vibration plate are joined so as to cover all the individual ink paths and grooves.

In the print head of the present invention, since a large number of grooves different from the individual ink paths are formed in the ink path plate, when compared with a head of the same size, the connection between the ink path plate and the vibration plate is smaller than before. The area can be reduced, and defects such as floating and cracks due to the difference in thermal expansion coefficient between the ink path plate and the diaphragm can be eliminated. In addition, by reducing the bonding area, it is possible to reduce bonding defects due to foreign matter intervention on the bonding surface.

Of course, the groove formed in the ink path plate does not communicate with the individual ink path, but is separated from the individual ink path. It is important that the joint area between the diaphragm and the diaphragm be as small as possible and that sufficient joint strength be ensured. For this purpose, as described in the following embodiments, grooves formed at equal intervals from the edge of the ink path plate and the individual ink paths are optimal, and the depth of the grooves is preferably the same as that of the individual ink paths. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet print head of the present invention and an electronic apparatus having the same will be described based on embodiments. FIG. 1 is a sectional view of a main part of an embodiment of a print head mounted on an electronic device such as a printer or a word processor. The structure of the electronic device other than the print head is not much different from the usual structure, and the print head will be mainly described here. The print head shown in FIG. 1 includes an ink path plate 10 in which a large number of individual ink paths 11 are formed at regular intervals, and an ink path plate 10 that covers all the individual ink paths 11 and grooves (described later).
, A common electrode 31 provided on the vibration plate 20, and a vibration plate 20 positioned on the individual ink path 11.
(That is, the piezoelectric element 3 attached to each part on the common electrode 31)
0 and an individual electrode 32 provided on each piezoelectric element 30.

The individual ink path 11 has a shape as shown in FIG. 2, and is composed of a supply path 12, a pressure chamber 13, and a nozzle 14 that extend from the rear end to the front end of the ink path plate 10. Further, grooves 15 to 18, which are features of the present invention, are formed in the ink path plate 10. These grooves 15-18
Are equally spaced from the edge of the ink path plate 10 and the individual ink paths 11 and along the individual ink paths 11.
Of these, the left and right grooves 15 and 16 extend from the rear end to the front end of the ink path board 10, and the grooves 17 and 18 existing between the individual ink paths 11 at the rear end and the front end of the ink path board 10.
Extend by the length of the supply path 12 and the length of the nozzle 14, respectively. FIG. 3 is a sectional view of the ink path board 10 having such grooves 15 to 18 taken along line AA. As can be seen from FIG. 3, the individual ink path 11 and the grooves 15 to 18 have the same depth.

Each piezoelectric element 30 affixed on the vibration plate 20 is located on the pressure chamber 13 of the individual ink path 11 as shown by a two-dot chain line in FIG. In the print head having such a configuration, when a voltage is applied to the common electrode 31 and the individual electrode 32, an electric field is applied to the piezoelectric element 30 sandwiched between the electrodes 31 and 32, and the piezoelectric element 30 is displaced.
Due to this displacement, the corresponding portion of the vibration plate 20 is deformed, the ink volume of the individual ink path 11 increases and decreases, and the ink of the individual ink path 11 whose ink volume has started to decrease is ejected from the nozzle 14.

Next, the production of the print head will be briefly described, except that the formation of a groove is added, and the production process is exactly the same as the conventional one. That is, first, the ink path plate 1
For example, the individual ink paths 11 and the grooves 15 to 18 are formed by, for example, etching. In this etching, the ink path plate 10 may be etched using a mask having a pattern as shown in FIG. It is not necessary to add the step of.

After the etching, the ink path plate 10 and the separately prepared vibration plate 20 are aligned, and both are heated and fused while being pressed. FIG. 4 shows the joined state immediately after the fusion. FIG. 4 is an enlarged sectional view of a portion corresponding to line AA shown in FIG. The ink path plate 10 and the vibration plate 20 are joined to each other at a joint 4 at a partition wall between the supply path 12 of the individual ink path 11 and the groove 17.
A value of 0 indicates mutual close contact. Of course, all the contact portions between the ink path 10 and the vibration plate 20 are in such a joined state. When cooling after heating, the ink
Since the joint area between the diaphragm 20 and the diaphragm 20 is small, even if, for example, the coefficient of thermal expansion of the ink path plate 10 is larger than that of the diaphragm 20, the joint 40 does not peel off as shown in FIG. The diaphragm 20 is only slightly curved upward, and no lifting or cracking of the diaphragm 20 at the joint surface occurs.

Next, after the common electrode 31 is provided on the vibration plate 20, the piezoelectric elements 30 are attached to each part of the common electrode 31 located on the pressure chamber 13 of the individual ink path 11, and Are provided with individual electrodes 32. Then, the produced print head is incorporated in a cartridge for mounting on an electronic device. Note that the shapes of the individual ink paths and the grooves shown in the above embodiments are merely examples, and it goes without saying that various forms can be taken. Further, in the above embodiment, similarly to the individual ink path, the groove may penetrate the edge of the ink path plate. In this case, when the ink path plate and the vibration plate are joined, the air in the groove is exposed to the outside. , It becomes easier to join.

[0015]

As described above, the ink jet print head of the present invention has the following effects because the ink path plate has grooves formed separately from the individual ink paths. (1) The joint surface between the ink path plate and the vibration plate is free from defects such as floating and cracking, and the yield is improved. (2) The same manufacturing process as the conventional one is required, and the bonding strength is high and the reliability is high. (3) Form a groove by providing a space between individual ink paths
Not the empty space between the individual ink paths and both ends
Since a groove is formed in the space outside the individual ink path of
Miniaturization and high density are not impaired.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a print head according to an embodiment of the present invention.

FIG. 2 is a plan view of an ink path plate in the print head shown in FIG.

3 is a cross-sectional view of the ink path board shown in FIG. 2, taken along line AA.

FIG. 4 is a partially enlarged cross-sectional view showing a state immediately after the ink path plate and the vibration plate have been heated and joined in the manufacture of the print head shown in FIG. 1;

FIG. 5 is a partially enlarged cross-sectional view showing a joined state of the ink path plate and the vibration plate when cooled from the state shown in FIG. 4;

FIG. 6 is a plan view of an ink path plate in a print head according to a conventional example.

FIG. 7 is a sectional view of the ink path board shown in FIG. 6 taken along line BB.

8 is a partially enlarged cross-sectional view showing a state immediately after the ink path plate and the vibration plate are heated and joined in the manufacture of the print head having the ink path plate shown in FIG. 6;

FIG. 9 is a partially enlarged cross-sectional view showing a joined state of the ink path plate and the diaphragm when cooled from the state shown in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ink path plate 11 Individual ink path 15-18 Groove 20 Vibration plate 30 Piezoelectric element 40 Joining part between ink path plate and vibration plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-344252 (JP, A) JP-A-5-16344 (JP, A) JP-A-3-293143 (JP, A) JP-A-4-344 345856 (JP, A) JP-A-55-82664 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/045 B41J 2/01 B41J 2/055

Claims (2)

(57) [Claims] An ink path plate formed with a large number of individual ink paths extending from one end to the other end at regular intervals; a vibration plate joined to the ink path plate so as to cover all the individual ink paths;
An ink jet print head comprising: a piezoelectric element provided at each portion on a vibration plate located on an individual ink path; wherein the individual ink path is directed from a rear end to a front end of the ink path plate.
The narrow supply path, the wide pressure chamber and the narrow width
Ink composed of nozzles and forming this individual ink path
Narrow width between supply paths and narrow width between individual ink paths on road board
In addition, an island-shaped groove is formed between the nozzles of
Each individual ink path outside the individual ink path at the end
A groove extending from the rear end to the front end along the line, and the ink path plate and the vibration plate are joined so as to cover all the individual ink paths and grooves. 2. An electronic apparatus comprising the inkjet print head according to claim 1.