JPH0764058B2 - Ink jet head and method of manufacturing the same - Google Patents

Description

The present invention relates to an inkjet head and a method for manufacturing the same, and more particularly to an inkjet head used in an ink recording apparatus and a method for manufacturing the same.

[Conventional technology]

Among the inkjet recording technologies, on-demand type inkjet heads have been expected to provide a recording apparatus with a simple structure, small size, and low cost.

FIG. 6 is a sectional view of an example of a conventional inkjet head.

As shown in FIG. 6, the ink jet head has a pressure chamber 12 for applying a pulse-like pressure to the ink inside a flat plate-integrated structure 1b made of a ceramic material, and a nozzle 11 for connecting the pressure chamber 12 and ejecting the ink. And ink reservoir 13,
An ink supply port (14) for replenishing the ink consumed by the ink ejection.

An actuator 4 made of a piezoelectric material is provided on the outer wall of the pressure chamber 12.
Is fixed, and the actuator 4 is operated by the voltage pulse from the drive circuit 5 to deform the outer wall of the pressure chamber 12 to eject the ink.

In such an inkjet head, it is known that when the viscosity of the ink changes, the speed and volume of the ink droplets ejected from the nozzle 11 change even if a voltage pulse having the same drive voltage waveform is applied.

In general, the ink used in the inkjet head greatly changes with temperature, so that the print quality is degraded due to the change in the size of the printed dots and the print position.

In order to prevent this, conventionally, a heater is attached to the outside of the inkjet head, or a heating element is printed on the outer wall of the head to control the temperature of the head to be constant.

Further, there is an ink recording apparatus that uses a so-called hot melt ink that is solid at room temperature and is heated to be a liquid at the time of use. The structure of the inkjet head used in the apparatus is the same as that of the above-described inkjet head. However, in this case, the entire inkjet head is used by being heated to a temperature at which the ink changes. Even when hot melt ink is used, it is common to heat the inkjet head with a heater from the outside.

[Problems to be solved by the invention]

In the conventional inkjet head described above, the heater is heated from the outer wall of the structure, and the heater comes into contact with only a part of the structure. Therefore, the temperature rises locally, and the entire structure has a uniform temperature. It is difficult to do so.

Further, generally, in a water-based ink, when the temperature becomes high, air bubbles are generated inside and ink deterioration due to a chemical change occurs. Therefore, it is necessary to suppress the heating temperature by the heater low, and local heating causes the entire structure to be damaged. The drawback is that it takes time to warm up.

Furthermore, if a heating element is formed on the outer wall of the structure by printing or the like, it is possible to heat the entire head uniformly.
As shown in FIG. 7, it has a drawback that it cannot be applied to the actuators formed on both sides of a flat plate structure.

An object of the present invention is to provide an inkjet head that can uniformly heat the entire structure and a method for manufacturing the inkjet head.

[Means for solving problems]

The inkjet head of the present invention is a flat plate integrated structure made of a ceramic material having electromechanical conversion characteristics,
In an inkjet head having a plurality of holes that serve as a plurality of ink channels including a nozzle and a pressure chamber inside the structure, a plurality of heat generating members that are embedded alongside the holes and are arranged side by side by sandwiching the holes, and the pressure. And a plurality of actuators arranged so as to sandwich the heat generating material in the chamber region.

A method of manufacturing an inkjet head according to the present invention comprises a step of forming an ink flow path pattern having a nozzle hole, an ink flow path, a pressure chamber and an ink supply port on a film with a photosensitive resin, and a ceramic having an electromechanical conversion characteristic. A step of forming a first electrode on a first green sheet containing a material, a step of forming a second electrode on a second green sheet containing a ceramic material, and a step of forming a third electrode containing the ceramic material. Forming a heating element and a wiring conductor made of a resistor and a conductive material on the green sheet; the ink flow path pattern separated from the film; the first green sheet; the second green sheet; and the third green sheet.
And the green sheets are laminated in a predetermined order to form a green sheet group, the green sheet group is pressure-bonded to form an integrated laminate, and the ink flow path pattern of the laminate is removed. And then forming the holes to sinter the laminated body.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of the first embodiment of the present invention.

As shown in FIG. 1, in the present embodiment, a flat plate-integrated structure 1 made of a ceramic material, and a nozzle 11 inside the structure 1.
And a pressure chamber 12, an ink reservoir 13, and an ink supply port 14, which serve as a plurality of ink flow paths, a heating element 3 embedded in the structure 1 along the holes 2, and a pressure chamber. The actuator 4 includes an actuator 4 made of a piezoelectric material, which is provided on the outer wall portion of the structure 1 which is the outer wall of 12, and a drive circuit 5 which applies a drive voltage to the actuator 4.

By applying a drive voltage to the electrodes of the actuator 4, the outer wall of the pressure chamber 12 vibrates due to the piezoelectric effect, and the nozzle 11
Ink drops are ejected from.

As shown in FIG. 1, when the actuators 4 are formed on the upper and lower outer walls with the pressure chamber 12 interposed therebetween, the vibrations of the upper and lower outer walls are in opposite phases to each other, so that the vibration transmitted to the entire structure 1 is canceled out and becomes small. Become. Therefore, the vibration energy is efficiently used for the ink ejection, and the vibration of the inkjet head is suppressed to a small level, so that the vibration noise is reduced.

2 is a transverse sectional view taken along the line AA 'in FIG.

As shown in FIG. 2, the plate-integrated structure 1 has the holes 2 shown in FIG. 1 therein, and the holes 2 are formed by a plurality of nozzles 11.
And a plurality of pressure chambers 12 each connected to the nozzle 11,
It has an ink reservoir 13 to which all the pressure chambers 12 are connected, and an ink supply port 14 connected to the ink reservoir 13. An actuator 4 is provided on the outer wall of each pressure chamber 12.

FIG. 3 is a plan view of the heating element shown in FIG.

As shown in FIG. 3, the heating element 3 is the structure 1 shown in FIG.
A plurality of heating resistors 16 are provided in the wall including the holes 2 along the holes 2, and the electrodes 15 at both ends are connected to each other at substantially equal pitches. Thereby, uniform heating can be performed over the entire structure 1. The shape of the heating element 3 is not limited to this, and may be any shape as long as the heating resistance 16 is evenly distributed.

A generally known method can be used as a drive control method for the heating element 3. That is, by fixing the temperature sensor to a part of the outer wall of the structure 1 and controlling the current supply to the heating element 3 by the detection signal of this temperature sensor, the structure 1 can be maintained at the set temperature.

Next, FIG. 4 is a sectional view of a second embodiment of the present invention.

As shown in FIG. 4, the difference between the second embodiment of the present invention and the embodiment of the first invention shown in FIG. 1 is that the embodiment of the second invention has a structure 1 _a . The electrode 18 is formed of a ceramic material having a piezoelectric effect, and the electrode 18 is provided inside the wall of the hole 2 inside the structure 1 _a sandwiching the pressure chamber 12, and the electrode 19 parallel to the electrode 18 is provided on the outer wall of the structure 1 _a. That is.

By applying a drive voltage from the drive circuit 5 between the electrodes 18 and 19, the wall of the pressure chamber 12 is vibrated by the pressure of the piezoelectric effect and the nozzle
Ink is ejected from 11.

As described above, by forming the structure 1 _a with the piezoelectric ceramic material and providing the electrodes on the structure 1 _a , the productivity of the inkjet head can be improved.

Next, FIGS. 5 (a) to 5 (f) are cross-sectional views of the inkjet head showing the order of steps for explaining the manufacturing method of the second embodiment of the present invention.

As shown in FIG. 5A, a photosensitive resin 22 is coated on a carrier film 21 such as polyester and dried. In this case, the coating thickness is determined by the pore thickness. As the photosensitive resin 22, for example, an acrylic ultraviolet curable polymer material is used.

Next, as shown in FIG. 5B, a photosensitive resin is used by using a photomask 23 having a hole forming pattern such as nozzles and pressure chambers.
Exposed to 22.

Next, as shown in FIG. 5C, the unexposed portion of the photosensitive resin 22 is removed by development to form an ink flow path pattern 24.

Next, as shown in FIG. 5D, a ceramic green sheet 25 made of a piezoelectric material is prepared, and an electrode pattern 26 including electrodes and wiring having a predetermined shape is printed thereon. Platinum or a silver-palladium alloy is used for the metal material of the electrode. Further, via holes for leading out the internal electrodes to the outside are also formed in these green sheets at predetermined positions. Further, a heating element pattern 27 is printed on another green sheet 25 by using a resistor made of a terium oxide-based paste.

Next, as shown in FIG. 5 (e), these ceramic green sheets and the ink flow path pattern previously formed
The layer 24 separated from the carrier film 21 is laminated in a predetermined order and laminated and pressure-bonded to form a layered body 28 in which the electrode pattern 26, the heating element pattern 27, and the ink flow path pattern 24 are embedded.

Next, as shown in FIG. 5 (f), by heating the laminated body 28 at around 500 ° C. to remove the binder, the ink flow path pattern 24 is decomposed and the space occupied by the ink flow path pattern 24 is decomposed. Becomes the hole 2. Then, by sintering at about 1000 ° C., the electrodes 18 and 19 parallel to the inner and outer walls and the heating element 3 embedded in the inside are provided, and the holes 2 sandwiched by the heating element 3 are formed.
The structure 1 _a shown in FIG.

In the above-described embodiments, the actuators or the electrodes for piezoelectric are arranged in the upper and lower pressure chambers, but the present invention is not limited to this and one side may be used. Further, the electrode structure is not limited to two layers and may be a multilayer.

Further, as the ink to be used, it is also possible to use a hot melt ink which becomes a liquid when heated at room temperature and solid. In particular, in the ink jet head according to the present invention, since the heating element is inside the structure, the hot melt ink can be efficiently heated, and the waiting time when used in the recording apparatus can be shortened.

Further, when the structure becomes thick, it is possible to make the internal heat generation distribution more uniform by embedding a layer containing a heat generating element in multiple layers.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, according to the inkjet head and the manufacturing method thereof of the present invention, the electrodes and wiring for the actuator formed on the outer wall of the structure by embedding the heating element for heating in the structure of the inkjet head. There is an effect that the entire structure can be heated uniformly without any restrictions. Further, since uniform heating is possible, there is an effect that the entire structure can be heated to a desired temperature in a short time. Further, by embedding the heating element inside the structure, the productivity is improved and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view of the heating element of FIG. 1, FIG. 4 is a cross-sectional view of the second embodiment of the present invention, and FIGS. 5 (a)-(f). ) Are sectional views of the ink jet head shown in the order of steps for explaining the manufacturing method of the second embodiment of the present invention, FIG. 6 is a sectional view of the first example of the conventional ink jet head, and FIG. It is sectional drawing of the 2nd example of the conventional inkjet head. 1,1 _a , 1 _b …… Structure, 2 …… Void, 3 …… Heating element, 4 ・ ・ ・
… Actuator, 5 …… Drive circuit, 11 …… Nozzle, 12
...... Pressure chamber, 13 ...... Ink reservoir, 14 ...... Ink supply port,
15 …… electrode, 16 …… heat resistance, 18,19 …… electrode, 21 ……
Carrier film, 22 ... Photosensitive resin, 23 ... Photo mask, 24 ... Ink flow path pattern, 25 ... Green sheet, 26 ... Electrode pattern, 27 ... Heating element pattern.

Claims (2)

[Claims] 1. An ink jet head having a flat plate integrated structure made of a ceramic material having electromechanical conversion characteristics, and pores forming a plurality of ink flow paths including nozzles and pressure chambers inside the structure. An ink jet head comprising: a plurality of heat-generating members that are arranged alongside the holes and are embedded so as to sandwich the holes; and a plurality of actuators that are arranged so as to sandwich the heat-generating members in the pressure chamber region. 2. A step of forming an ink flow path pattern having a nozzle hole, an ink flow path, a pressure chamber and an ink supply port on a film by using a photosensitive resin, and a first step including a ceramic material having electromechanical conversion characteristics. Forming a first electrode on the green sheet, forming a second electrode on the second green sheet containing the ceramic material, and forming a resistor on the third green sheet containing the ceramic material. A step of forming a heating element and a wiring conductor made of a body and a conductive material, and the ink flow path pattern separated from the film, the first green sheet, the second green sheet, and the third green sheet. Stacking the green sheets in a predetermined order to form a green sheet group, pressing the green sheet group to form an integrated laminate, and A method of manufacturing an ink jet head which comprises a step of sintering the laminate after the holes by removing the ink flow path pattern.