JP2002355962A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent clogging of a nozzle hole or a pressure chamber with a dust intruding during manufacture by a simple arrangement and to realize high quality recording by absorbing pressure variation without requiring any special arrangement additionally thereby preventing crosstalk. SOLUTION: A substrate 11 having a plurality of pressure chambers 20 formed planarly, substrates 15, 16 and 17 having a common ink chamber 23 formed therein, and a substrate 13 having a plurality of filter holes 25 facing the other end of respective pressure chambers are laminated and ink is supplied from the common ink chamber 23 through the filter hole 25 to each pressure chamber. Furthermore, a space is formed in the substrate 13 on the side opposite to the common ink chamber wherein the region of the substrate 13 corresponding to the space is deformable as the pressure in the common ink chamber 23 varies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an ink jet head.

[0002]

2. Description of the Related Art An ink jet head supplies ink from an ink tank to a common ink chamber, distributes the ink from the common ink chamber to a plurality of pressure chambers, and selectively applies pressure to each pressure chamber. Ink droplets are ejected from the nozzle holes. A filter is provided at the opening of the ink jet head to which the ink tank is connected so as to prevent dust and the like from entering so that the nozzle hole and the pressure chamber are not blocked by foreign matter or the like that enters from the outside.

[0003]

However, dust and the like may enter the ink-jet head during manufacturing, and cannot be removed by the above-mentioned filter, thereby blocking the nozzle holes and the pressure chambers. . It is conceivable to provide a filter for nozzle holes and pressure chambers,
In a multi-nozzle type ink jet head, a large number must be provided in a fine portion.

Further, in order to prevent crosstalk due to pressure fluctuation at the time of ink ejection, a special configuration is required, and the structure is complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the possibility of closing a nozzle hole or a pressure chamber with dust or the like entering during manufacturing, and to realize it with a simple configuration. To provide an inkjet head that performs Furthermore, without adding a special structure, pressure fluctuations are absorbed to prevent crosstalk, thereby realizing excellent quality recording.

[0006]

According to the present invention, a common ink chamber is formed to be long in a row direction formed by a plurality of pressure chambers each having one end communicating with an ink discharge nozzle. The other end of each pressure chamber is opened in the common ink chamber, and in the ink jet head for supplying ink from the common ink chamber to each pressure chamber, a first substrate in which the plurality of pressure chambers are formed in one plane is provided. A second substrate formed in one plane parallel to a plane formed by the plurality of pressure chambers, and the common ink chamber is located between the two substrates;
A structure is provided in which a third substrate having a plurality of filter holes is stacked in a region facing the other end of each of the pressure chambers that opens into the common ink chamber.

As described above, by interposing the filter holes between the plurality of pressure chambers and the common ink chamber, dust or the like that enters during the manufacture of the ink jet head flows from the common ink chamber into the pressure chamber and enters the pressure chamber. To reduce the probability of existing in the flow path from the nozzle to the nozzle hole, and prevent the pressure chamber and the nozzle hole from being blocked. In addition, a third substrate having a filter hole is interposed between a first substrate having a plurality of pressure chambers and a second substrate having a common ink chamber, whereby a filter is provided for each of the plurality of pressure chambers. Enables easy installation.

Preferably, in the ink jet head, the third substrate extends in parallel with the common ink chamber, a space is provided on the opposite side of the common ink chamber, and the third substrate corresponding to the space is provided. Is made deformable in accordance with the pressure fluctuation in the common ink chamber, thereby absorbing the pressure fluctuation in the common ink chamber and preventing crosstalk.

The thickness of the third substrate is about 5 μm to
By making the diameter of the filter hole about 20 μm and the diameter of the filter hole about 15 μm, the above configuration can be easily realized.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

The ink jet head includes a cavity plate set 10 and an actuator unit 30.
The cavity plate set 10 has a structure in which a plurality of substrates 11 to 19 in which openings serving as ink flow paths are formed by etching are stacked and adhered to each other. The uppermost substrate 11 has a plurality of pressure chambers 20 arranged in a plurality of rows, for example, two rows and in one plane, and the lowermost substrate 19 has a plurality of nozzle holes 21 for discharging ink droplets. The other substrates 12 to 18 located between the two substrates each have a communication hole 22 for communicating one end of each pressure chamber 20 to the nozzle hole 21. The fifth to seventh substrates 15 to 17 are provided in each of the pressure chambers 2.
There are common ink chambers 23, 23 extending below the row of 0 corresponding to the row. The other end of each pressure chamber 20 is a restricted flow path 20a having a reduced cross-sectional area.
0a is a communication passage 24 of the second substrate 12 and a filter hole 2 of the third substrate 13 as shown in detail in FIGS.
The fifth and fourth substrates 14 communicate with the common ink chamber 23 through the communication holes 26. The third substrate 13 is a thin plate having a thickness of 5 to 20 μm and manufactured by electroforming and having elasticity, and has a diameter of 1 mm at a position facing the end of the communication passage 24 and the communication hole 26.
It has many filter holes 25 of 5 μm or less.

The two rows of pressure chambers 20 are positioned so that the ends on the nozzle hole 21 side face each other, and the pressure chambers 20 of each row extend in a direction crossing over the common ink chamber 23.
The communication hole 26 communicating with the other end of each of the pressure chambers 20 opens along the longitudinal side edge of the common ink chamber 23.
Between one end of the two rows of pressure chambers 20 and the two rows of communication holes 22 that connect the nozzle holes 21, a return path 27 is provided between the substrates 15-1.
8. That is, the common ink chambers 23, 23 and the return path 27 are parallel to a plane defined by the plurality of pressure chambers 20.
Located in two planes.

The return path 27 includes two common ink chambers 23,
23 extend parallel to their longitudinal direction, and one end thereof communicates with the same side end of both common ink chambers 23, 23. The other end of the return path 27 is connected to the cavity plate set 10.
The two common ink chambers 2 communicate with the opening 28
The other end of each of the third and third members communicates with an opening 29 that opens on the upper surface of the cavity plate set 10.

The actuator unit 30 is disclosed in
In a configuration similar to that described in JP-A-274159, piezoelectric ceramic layers and electrodes are alternately stacked and fixed on the upper surface of the cavity plate set 10, and at least one of the electrodes sandwiching the piezoelectric ceramic layer is connected to the pressure chamber 20. Are substantially similar to and slightly smaller than the above-mentioned plane shape. By applying a voltage between two electrodes sandwiching the piezoelectric ceramic layer, the piezoelectric ceramic layer in a portion corresponding to the pressure chamber 20 is deformed to apply pressure to the ink in the pressure chamber 20, and the ink is ejected from the nozzle holes 21. can do. The actuator unit 30 may apply an ejection pressure to the ink using a force such as local boiling of the ink due to static electricity or heat, in addition to the piezoelectric or electrostrictive deformation.

As shown in FIG. 3, an ink supply source, that is, an ink tank 40, stores ink therein,
It has two ink supply ports 41, 41 facing the respective openings 29, 29 of the two common ink chambers 23, 23, and a return port 42 facing the opening 28 of the return path 27. The three openings 28, 29, 29 of the cavity plate set 10 are located side by side on one side of the upper surface of the cavity plate set 10, and the ink tank 40 connects the ink supply ports 41, 41 and the return port 42 to each of the openings 28. , 29, 29 and can be easily and detachably mounted on one side thereof.

The ink tank 40 has a first chamber 44 which communicates an internal ink storage chamber with the ink supply ports 41, 41.
And a second wall 45 communicating with the return port 42. A one-way flow passage means for allowing the flow of ink from the second chamber 45 to the first chamber 44 is provided on the partition wall 43. 46. The first chamber 44 is connected to a flow unit 47 that applies pressure to the ink so that the ink in the room flows from the ink supply ports 41 into the cavity plate set 10. As the flow means 47, for example, a means for increasing the pressure in the first chamber 44 by a blower, a compressor, or the like to pressure-feed the ink from the ink supply ports 41, 41, or a liquid pump disposed in the ink supply ports 41, 41 is used. Can be used. One-way channel means 46
Known one-way flow valve, or
Two valve means can be used, similar to that described in US Pat. The flow means 47 and the one-way flow path means 46 constitute a forced circulation means.

In a normal recording state, the flowing means 47 is not driven. After or before the ink is ejected from the pressure chamber 20, ink is supplied from the common ink chamber 23 to the pressure chamber 20 with the deformation of the actuator unit 30, and the ink is supplied from the ink tank 40 to the common ink chamber 23. Replenish through mouth 41.

At this time, the common ink chamber 23 and the pressure chamber 2
Since a large number of filter holes 25 are located in the flow path to zero,
It is possible to reduce the probability that dust or the like that has entered during the manufacturing process flows from the common ink chamber into the pressure chamber and is present in the flow path from the pressure chamber to the nozzle hole. Can also be prevented from flowing into the pressure chamber, and the flow path from the pressure chamber 20 to the nozzle hole 21 can be prevented from being blocked. The filter may be provided not only in the above-mentioned filter but also in the opening 29.

When the flow means 47 is driven to remove air bubbles and dust accumulated in the common ink chamber 23 and the like, the ink in the ink tank 40 is discharged at a higher speed than in the normal recording state. Through the common ink chamber 23
And flows from the common ink chamber 23 to the first chamber 44 of the ink tank through the return path 27, the return port 42 of the ink tank, and the one-way flow path means 46. Bubbles and dust in the common ink chamber 23 and the like can be collected in the ink tank 40 together with the rapid flow of the ink. At this time, it is desirable that the nozzle holes 21 of the cavity plate set 10 be covered with a known cap 50. Cap 5 if necessary
0, the pressure chamber 20, the communication hole 23,
By sucking the ink in the nozzle holes 21, air bubbles, ink that has started to dry, and the like therein can be removed. By the ink circulation operation and the suction operation, the ink ejection state can be recovered or maintained satisfactorily. In the suction operation, it is not necessary to discharge a large amount of ink in the common ink chamber 23, so that there is little wasted ink.

Further, in order to prevent crosstalk due to pressure fluctuation at the time of ink ejection, the mechanical rigidity of a part of the common ink chamber 23 is reduced. For example, as shown in FIG. 2, at the end opposite to the opening 29 of the common ink chamber 23, that is, at the end connected to the return path 27, the other end of each pressure chamber is separated from the region communicating with the common ink chamber. In the region, a portion 23a wider than the region where the other end of the pressure chamber communicates with the common ink chamber is provided. As shown in FIG. 4, the portions of the substrates 12, 14 corresponding to the wide portions 23a are openings 12a, 14a, and the lower surface of the corresponding portion of the substrate 13 faces the wide portion 23a. By doing so, the portion of the substrate 13 is elastically deformed by pressure fluctuation.

With the above configuration, when ink is ejected from a number of pressure chambers 20 at the same time, the pressure fluctuates from the pressure chambers 20 to the common ink chamber 23. Since a relatively fast ink flow is generated from the opening 29 to the wide portion 23a side in the ink chamber 23, the pressure wave generated in the common ink chamber 23 is caused by the ink flow, The pressure fluctuation is buffered by the fact that the common ink chamber 23 has an enlarged cross-sectional area at the wide portion 23a. Further, the substrate 13 corresponding to the wide portion 23a is elastically deformed to absorb the pressure fluctuation, and it is possible to prevent the crosstalk in which the pressure fluctuation is exerted on the pressure chamber at the next ink discharge.

The provision of the wide portion 23a and the elastic deformation of the substrate 13 are most effective when used together, but only one of them may be used. The upper portion of the wide portion 23a may be provided only with the substrate 14 without providing the substrates 11 to 13, and the lower portion may be provided with only the substrate 19, so that the substrates 14, 19 may be elastically deformed. In other words, the portion (13 or 14, 19) of the cavity plate set 10 that forms the wide portion 23a has a significantly wider mechanical rigidity than the other portions by including a wide space, and the pressure fluctuation It is easy to absorb
It is preferable that it is thinner like the substrate 13.

At this time, if the rigidity of the portion of the common ink chamber 23 corresponding to the pressure chamber is weakened, the mechanical rigidity of the cavity plate set 10 varies between the center and both ends of the row of pressure chambers, and The pressure generated varies.
Although it becomes impossible to perform the ink ejection uniformly, as described above, by forming the wide portion 23a in a region away from the region where the other end of the pressure chamber communicates with the common ink chamber, the rigidity with respect to all the pressure chambers is increased. And the ink can be discharged uniformly.

Since the filter hole 25 is interposed between the pressure chamber 20 and the common ink chamber 23 as described above, the pressure wave from the pressure chamber 20 to the common ink chamber 23 is And the crosstalk prevention effect can be further enhanced. Further, since the wide portion 23a is formed wide on the opposite side to the return path 27, the wide section 23a can be provided without limiting the size and arrangement of the return path 27, and the ink jet head can be reduced in size.

[0025]

As is apparent from the above description,
The present invention reduces the probability that dust or the like entering during the manufacture of an inkjet head flows from the common ink chamber into the pressure chamber and exists in the flow path from the pressure chamber to the nozzle hole, and closes the pressure chamber and the nozzle hole. Can be prevented. Also,
By interposing a third substrate having a filter hole between a first substrate having a plurality of pressure chambers and a second substrate having a common ink chamber, a filter can be easily formed for each of the plurality of pressure chambers. Can be installed.

Further, a space is formed on the third substrate on the side opposite to the common ink chamber, and a region of the third substrate corresponding to the space is deformable in accordance with a pressure change in the common ink chamber. Crosstalk can be prevented by absorbing the pressure fluctuation in the ink chamber, and as a result, excellent quality printing can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an inkjet head according to an embodiment of the present invention, which is a cross-sectional view taken along line AA of FIG.

FIG. 2 is a plan view of the inkjet head of FIG. 1 with an actuator unit removed.

3 is a cross-sectional view showing a state in which an ink tank is mounted on the inkjet head of FIG. 1, and is a cross-sectional view corresponding to a cross-sectional position taken along line BB of FIG. 2;

FIG. 4 is a sectional view taken along line CC of FIG. 2;

FIG. 5 is an enlarged sectional view of a filter hole portion of FIG.

FIG. 6 is an enlarged perspective view of a filter hole part of FIG. 1;

[Explanation of symbols]

 11 to 19 substrate 20 pressure chamber 23 common ink chamber 25 filter hole 27 return path 40 ink tank

Claims (3)

[Claims] 1. A common ink chamber is formed to be long in a column direction formed by a plurality of pressure chambers each having one end communicating with a nozzle for discharging ink, and the other end of each pressure chamber is opened into the common ink chamber. In an ink-jet head for supplying ink from a common ink chamber to each pressure chamber, a first substrate in which the plurality of pressure chambers are formed in one plane, and a plane formed by the plurality of pressure chambers as the common ink chamber A second substrate formed in one parallel plane and a third substrate having a plurality of filter holes in a region located between the two substrates and opposed to the other end of each of the pressure chambers opened to the common ink chamber; An ink jet head comprising: a substrate; 2. The third substrate extends in parallel with the common ink chamber, a space is provided on the opposite side of the common ink chamber, and a region of the third substrate corresponding to the space is provided with common ink. 2. The ink jet head according to claim 1, wherein the ink jet head can be deformed in accordance with a change in pressure in the room. 3. The thickness of the third substrate is from about 5 μm to about 2 μm.
3. The ink jet head according to claim 1, wherein the diameter of the filter hole is about 15 [mu] m.