JP3384418B2 - Inkjet recording head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated type ink jet recording head.

[0002]

2. Description of the Related Art In order to make a recording head more compact, an ink jet recording head using a piezoelectric electrostrictive film type actuator that exerts a bending displacement force in a direction perpendicular to a plate surface by a lateral effect of electric field induced strain JP-A-6-40
It is disclosed in Japanese Patent Publication No. 030.

In this type of recording head, as shown in FIG. 2, a nozzle plate b having a plurality of nozzle holes a is provided.
And a plate unit h for forming an ink flow path, which is a stack of an ink supply plate g having a supply port f connecting the reservoir plate d forming the ink flow path part c and the pressure chamber e.
A spacer plate i forming a pressure chamber e, a vibration plate j covering the opening of the spacer plate i, and an ink supply plate g on the back surface of the ink flow path forming plate unit h.
And a connection plate 1 having a communication port k for connecting with the pressure chamber forming plate unit m formed by stacking green sheets, and formed on the outer surface of the diaphragm j by a film forming method. A piezoelectric / electrostrictive element q including the electrodes n and o and the piezoelectric / electrostrictive layer p is formed.

The plate-shaped unit h for forming the ink flow path is made of plastic, metal such as nickel and stainless steel,
The pressure chamber forming plate-shaped unit m is formed as an integrally fired product of ceramics.

[0005] However, in such Printout recording apparatus, FIG. 3, as shown in FIG. 4, the pressure chamber forming plate unit m
There results that are surrounded by the head supporting base r, have occurred frequently inconvenient when exposed to a low-temperature environment.

As a result of investigating the cause, the shape of the head supporting substrate r and the heat capacities of the ink channel forming plate unit h and the pressure chamber forming plate unit m are related to the damage of the pressure chamber e. I understood it.

The ink in the recording head exposed in a low temperature environment is cooled from a portion which is in direct contact with cold outside air and freezes while expanding in volume.

That is, in FIG. 3 and FIG. 4, since the head supporting base body r is configured to be firmly fixed including the recording head and the flexible circuit board t connected to the piezoelectric / electrostrictive element q, a pressure chamber is formed. Since the plate-shaped unit m side does not come into direct contact with the outside air, and the accommodating recess s of the pressure-chamber forming plate-shaped unit m is in a sealed state, it is in direct contact with the cold outside air when exposed to a low temperature environment. As a result of the ink on the nozzle plate b side being cooled first and the ink inside being frozen in the flow path portion, the ink on the pressure chamber forming plate-shaped unit m side that was frozen later in the pressure chamber e causes volume expansion. Since the location of the output is determined on the diaphragm j side, an excessive force is applied to the diaphragm j, and the joint portion or the diaphragm j itself is damaged.

Further, the smaller the heat capacity of the constituent members, the faster the cooling. Therefore, even in the case of the recording head alone, when the ink flow path forming plate unit h is made of plastic or in the pressure chamber forming plate shape. When the shape of the unit m becomes large, the heat capacity of the plate-shaped unit m for forming the pressure chamber becomes larger than that of the plate-shaped unit h for forming the ink flow path. I found it to cause.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and its purpose is to prevent damage to the pressure chamber even when exposed to a low temperature environment. It is to provide a new laminated type ink jet recording head which does not exist.

[0011]

That is, according to the present invention, as an ink jet recording head for achieving such a subject, a series of ink passages from an ink supply portion to a nozzle via a pressure chamber is laminated with a plurality of thin plate materials. In the recording head assembly constituted by the body, the heat capacity of the pressure chamber forming plate unit fixed to the back surface of the ink channel forming plate unit reaching the nozzle is set to The recording head assembly is formed so as to have a smaller heat capacity than that of the recording head assembly, and is integrally attached to a support base formed so that the pressure chamber forming plate-shaped unit side communicates with the outside air.

[0012]

With this configuration, even when the ink jet recording head is placed in a low temperature environment, the ink on the side of the pressure chamber forming plate-shaped unit having a small heat capacity is frozen first, and the ink volume-expanded is used as ink. The pressure applied to the diaphragm is released by escaping into the flow path on the side of the flow path forming plate unit, and the damage is suppressed in advance.

[0013]

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

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, an ink flow path forming plate-like unit 10 is provided with a nozzle plate 12 in which a large number of nozzles 11 are arranged in rows, a through hole 13 communicating with the nozzles 11 and an ink supply on a support substrate (not shown). A reservoir plate 15 having a reservoir chamber 14 communicating with the passage, and a nozzle 1
1 and the ink supply plate 18 having a through hole 16 connecting the reservoir chamber 14 and the pressure chamber 24 to each other, and both widthwise ends of the nozzle 11 in the direction orthogonal to the row. Is directly fixed to the top surface of a support base (not shown).

On the other hand, the pressure chamber forming plate unit 20 integrally fixed to the back surface of the ink flow path forming plate unit 10 with an adhesive is the reservoir chamber 14
And a connection plate 23 having a through hole 21 connecting the pressure chamber 24 and a through hole 22 connecting the pressure chamber 24 and the nozzle 11,
A spacer plate 25 in which the pressure chamber 24 is formed and a vibrating plate 26 covering the opening of the pressure chamber 24 are integrally sintered as a substrate made of a ceramic material, and the density, specific heat and volume of the ceramic material are The heat capacity determined by the product of the above is smaller than the heat capacity of the ink flow path forming plate unit 10 described above.

Reference numeral 30 is a support base for supporting a recording head assembly comprising the ink flow path forming plate-like unit 10 and the pressure chamber forming plate-like unit 20. The support base 30 has a top surface 31. A stepped recess 32 for positioning and fixing both widthwise ends of the plate unit 10 for forming the ink flow path.
Is formed, and the inner side thereof is a window hole 34 that opens to the back surface through the accommodation recess 33 of the pressure chamber forming plate unit 20.
And a plate-shaped unit 10 for forming an ink flow path
The pressure chamber forming plate-shaped unit 20 fixed to the back surface is directly contacted with the outside air.

[0018] Thus configured, and if the ink jet recording head in which ink is filled inside is now placed under a low temperature environment, through the window hole 34 provided in the supporting base 30
The pressure chamber forming plate unit on 20 is in direct contact with the outer air,
It is exposed to the same temperature conditions as the ink flow path forming plate unit 10. Therefore, the plate unit 1 for forming the ink flow path
Than the thermal capacity of 0 Ink small fence formed minute pressure chamber forming plate unit 20 is frozen is cooled faster than the ink in the ink flow path forming plate unit 10, the frozen
Through holes 16 and 1 on the side of the plate unit 10 for forming the ink flow path, in which the ink volume-expanded by binding has not frozen yet
The pressure applied to the vibrating plate 26 is reduced as much as possible while allowing it to escape into the inside 7 to prevent damage to this portion made of the ceramic material.

Following this, the ink on the ink channel forming plate-shaped unit 10 side also begins to freeze within the channel, and the channels provided here are the ink supply channel side of the support base 30 and the nozzle 11 side. Since the ink is opened in the and, the ink corresponding to the volume expansion escapes to these passages and suppresses the damage on the ink flow path forming plate unit 10 side.

Thus, the pressure chamber forming plate-like unit 2
In order for 0 to freeze first, the heat capacity must be smaller than that of the ink flow path forming plate unit 10.

In addition, a material satisfying the above-mentioned conditions in constructing the recording head will be described.

The ink flow path forming plate-like unit 10 is required to have highly precise fine holes such as the nozzle 11, the through hole 13, the through hole 16 and the through hole 17. Metals such as stainless steel and nickel were suitable as the material for achieving this.

Further, the pressure chamber forming plate unit 20 is required to be capable of easily securing the sealing property of the ink flow path and having good manufacturability. As a material for achieving this, it is possible to perform integral firing. Ceramics were suitable.

In this way, the material of the plate unit 10 for forming the ink flow path is metal, and the plate unit 2 for forming the pressure chamber is used.
When the material of No. 0 is ceramics, the heat capacity of the pressure chamber forming plate unit 20 can be made smaller than that of the ink flow path forming plate unit 10.

In this embodiment, the pressure chamber forming plate-shaped unit 20 can be brought into direct contact with the outside air, and at the same time, the flexible circuit board 28 connected to the actuator 27 by using the window 34 is impossible. There is also an effect that this can be pulled out of the support base 31 without being bent.

[0026]

As described above, according to the present invention, the heat capacity of the pressure chamber forming plate unit in the laminated ink jet recording head assembly is higher than that of the ink flow path forming plate unit. small form, by supporting the support base to thus recording head assembly for opening the pressure chamber forming plate unit to the outside air, even if the ink jet recording head is put under extreme low temperature environment, the ink
And earlier frozen small not ink in the pressure chamber forming plate unit side heat capacity than the flow path forming plate unit, volume expanded the minute ink ink flow path forming plate unit <br/> side it is possible to prevent the damage of the pressure chamber I'm to be released to.

[Brief description of drawings]

FIG. 1 is a side view of a recording head assembly showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing a conventional inkjet recording head.

FIG. 3 is a side sectional view showing a conventional inkjet recording head.

FIG. 4 is a front sectional view showing a conventional inkjet recording head.

[Explanation of symbols]

10 Ink flow path forming plate unit 20 Plate-shaped unit for pressure chamber formation 30 support substrate 32 Stepped recess for positioning and fixing plate unit 33 Ceramic base recess 34 window hole

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-6-40030 (JP, A) JP-A-5-261919 (JP, A) JP-A-4-355147 (JP, A) JP-A-5- 220952 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/175

Claims (2)

(57) [Claims] 1. In a recording head assembly in which a series of ink passages from an ink supply unit to a nozzle via a pressure chamber is composed of a laminate of a plurality of thin plate materials, an ink flow path forming plate material unit to the nozzle is formed. The heat capacity of the pressure chamber forming plate member unit fixed to the back surface is formed to be smaller than the heat capacity of the ink flow path forming plate unit, and the recording head assembly is attached to the pressure chamber forming plate unit side. An ink jet recording head, wherein the ink jet recording head is integrally attached to a supporting base formed so as to communicate with the outside air. 2. The ink jet recording head according to claim 1, wherein the plate material unit for forming the ink flow path is made of metal, and the plate unit for forming the pressure chamber is made of ceramics.