JPH05112005A - Ink jet printer head - Google Patents

Abstract

PURPOSE:To prevent an ink jet printer head from crosstalk and to improve the quality of printing and printing speed. CONSTITUTION:Two main body plates 26 wherein the apex part is a piezoelectric member 22 and the end part is a non-piezoelectric member 23 and a number of partition walls 24 are stood, are provided and the piezoelectric member 22 on another partition wall 24 is positioned between non-piezoelectric members 23 of pertition walls 24 of one side by integrating these main body plates 26 and structural crosstalk is prevented from occurrence by pressing an ink in a pressurizing room 28 by means of a piezoelectric member 2 and electrode layers 20 and 21 on adjoining partition walls 24 are separated from each other to prevent also electric crosstalk from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink jet printer head.

[0002]

2. Description of the Related Art At present, as an inkjet printer head capable of quiet and high-density printing, an inkjet printer head for ejecting ink droplets from an orifice to fix the ink onto a printing paper has been put into practical use.

For example, an on-demand type ink jet printer head has a structure in which a pressure generating means at least the surface of which is displaceable is provided in a pressure chamber communicating with each of the orifices arranged in an array. Then, in such an inkjet printer head, the pressure generating means is vibrated by the drive power corresponding to the print image, and the ink in the pressure chamber is ejected as an ink droplet from the orifice.

At present, it has been proposed to use a pre-polarized piezoelectric member as the pressure generating means of the ink jet printer head as described above. Therefore,
As a conventional example of such an ink jet printer head, two devices disclosed in Japanese Patent Laid-Open No. 2-208050 are shown in FIG.
And it demonstrates based on FIG. First, as illustrated in FIG. 4, the first inkjet printer head 1 has a piezoelectric member 4 having upper and lower electrode layers 2 and 3 formed on the upper and lower surfaces thereof.
A main body plate 7 in which the partition walls 5 made of non-piezoelectric material are continuously provided on a base substrate 6 made of a non-piezoelectric member is provided, and the two main body plates 7 are integrally joined to form a recess between the one partition wall 5 and the other partition wall 5. A structure in which pressure chambers 8 are formed by sealing at the top surface of the above, and an orifice plate 10 having an orifice 9 formed at a position communicating with these pressure chambers 8 is integrally joined to the end faces of the two main body plates 7. Has become. In this inkjet printer head 1, the piezoelectric member 4 of each body plate 7 is polarized from the upper electrode layer 2 toward the lower electrode layer 3. Further, in the inkjet printer head 1, the upper electrode layers 2 that are in contact with each other in a disposition manner are insulated from each other by forming an insulating protective film (not shown) on the surfaces of the two body plates 7.

In the ink jet printer head 1 having such a structure, the three piezoelectric members 4 surrounding one pressure chamber 8 are simultaneously driven by selectively switching the energization direction, so that the predetermined orifice 9 is discharged. It is designed to eject ink drops.

In the body plate 7 of the ink jet printer head 1 as described above, for example, the lower electrode layer 3, the piezoelectric member 4 and the upper electrode layer 2 are sequentially laminated on the base substrate 6 and then the concave groove is cut. It is manufactured by processing.

Further, another ink jet printer head 11 disclosed in the above publication, as illustrated in FIG.
Piezoelectric member 14 having electrode layers 12 and 13 formed on both side surfaces
A main body plate 16 having a partition wall 15 formed therein is provided, and the other partition wall 15 is disposed in the concave groove between the one partition wall 15 by integrally joining the two main body plates 16, and the RTV is provided between the side surfaces of these partition walls 15. (Room Temperature Valcanization)
The pressure chamber 18 is formed by sealing with the rubber 17.
In the ink jet printer head 11, the piezoelectric member 14 of each body plate 16 has one electrode layer 12
Is polarized toward the other electrode layer 13.

In such a structure, the ink jet printer head 11 also drives the three piezoelectric members 14 surrounding one pressure chamber 18 at the same time by selectively switching the energizing direction similarly to the ink jet printer head 1 described above. By doing so, ink droplets are ejected from the predetermined orifice 9.

[0009]

In the ink jet printer heads 1 and 11 disclosed in the above publication, the three piezoelectric members 4 and 14 are simultaneously driven to form one orifice 9
It is designed to eject ink droplets from.

However, in the ink jet printer heads 1 and 11 described above, since the piezoelectric members 4 and 14 are structurally communicated with the three pressure chambers 8 and 18, the ink in one pressure chamber 8 and 18 is ink. When the three piezoelectric members 4 and 14 are deformed to pressurize them, the piezoelectric members 4 and 14 are deformed.
The pressure fluctuations inevitably occur in the ink in the other pressure chambers 8 and 18 communicating with. When unnecessary pressure fluctuations occur in the pressure chambers 8 and 18 that are not driven in this way, minute ink droplets may protrude from the orifice 9 that communicates with the pressure chambers 8 and 18, and Print quality will be degraded due to crosstalk.

Further, the piezoelectric members 4 and 14 as described above.
Even if the crosstalk can be prevented by the drive control of the ink, it is difficult to stably eject the ink in the pressure chambers 8 and 18 in which the pressure fluctuations act as ink droplets until the vibration is reduced. The speed will decrease.

When ink droplets are ejected from a certain orifice 9, the piezoelectric members 4 and 14 facing the pressure chambers 8 and 18 in the vertical direction expand in the vertical direction and contract in the horizontal direction. The ink in the pressure chambers 8 and 18 located at is depressurized and ink droplets cannot be ejected. Similarly, the piezoelectric members 4 and 14 located in the left and right directions of the pressure chambers 8 and 18 for ejecting ink droplets pressurize the other left and right direction pressure chambers 8 and 18, but the up and down direction pressure chambers 8 and 18.
Since 18 is depressurized, ink droplets cannot project. That is, in the inkjet printer heads 1 and 11,
At the same time, the number of orifices 9 that can pressurize the pressure chambers 8 and 18 to cause the ink droplets to project is half the total number, and therefore the printing speed thereof is reduced.

The present invention provides an ink jet printer head for high quality printing at high speed.

[0014]

A pre-polarized piezoelectric member is arranged in a pressure chamber in which an orifice and an ink supply passage communicate with each other, and ink supplied from the ink supply passage and held in the pressure chamber is retained. In an inkjet printer head configured to pressurize with the piezoelectric member that deforms according to applied power and to discharge from the orifice, the piezoelectric member having electrode layers on the upper and lower surfaces forms a front end and a non-end end. A large number of partition walls formed of piezoelectric members are provided on a flat base to provide two main body plates, and these main body plates are integrally joined to each other so that one partition wall has a non-piezoelectric member and the other partition wall has a piezoelectric element. The sex member was arranged.

[0015]

Since the ink in one pressure chamber can be individually pressurized by one piezoelectric member, it is possible to prevent the print quality from deteriorating due to structural crosstalk, and to prevent the electrode layers of the adjacent partition walls from being separated from each other. Can be separated,
It is possible to prevent deterioration of print quality due to electrical crosstalk, and it is possible to drive each piezoelectric member at the same time, so that the printing speed can be increased, and an inkjet printer head that performs high-quality printing at high speed. Is what you get.

[0016]

Embodiments of the present invention will be described with reference to FIGS. Note that FIG. 1 illustrated here is a vertical sectional front view of the inkjet printer head 19 illustrated in FIG. 2 taken along line BB, and FIG. 2 illustrates the inkjet printer head 19 illustrated in FIG. It is a vertical side view taken along a line. First, as shown in FIG. 1, the ink jet printer head 19 has a piezoelectric member 22 having electrode layers 20 and 21 formed on the upper and lower surfaces at the front end and a non-piezoelectric member 23 at the end. A plurality of separated partition walls 24 are provided on the base portion 25 with two main body plates 26 erected in a comb-like shape, and these main body plates 26 are integrally joined to each other between the non-piezoelectric members 23 of one partition wall 24. The piezoelectric member 22 of the partition wall 24 is arranged. Therefore, in the ink jet printer head 19, the space formed by the top surface of the piezoelectric member 22 and the concave groove 27 between the partition walls 24 is a pressure chamber 28, which faces each of the pressure chambers 28. An orifice plate (not shown) having an orifice formed in a through hole is joined to the front surfaces of the two body plates 26 integrally joined.

In the ink jet printer head 19, the non-piezoelectric member 23 of the partition wall 24 of the main body plate 26 and the base portion 25 are integrally formed by cutting an insulating substrate, and the two main body plates are formed. 26 is joined by the convex portions 29 on both sides of the partition wall 24 which are formed in substantially the same shape as the non-piezoelectric member 23. In the inkjet printer head 19, the electrode layer 2
An insulating layer 30 and an adhesive layer 31 are formed between each of the electrode layers 20, 21 and the piezoelectric member 22.
The terminal portions 32 and 33 formed at the end portion of 21 are divided by the insulating layer 30. Further, as illustrated in FIG. 2, a step 34 is formed at the rear edge portion of the base portion 25 of the body plate 26 in which the terminal portions 32 and 33 are located, and the step 34 forms the two body portions. The terminal portions 32 and 33 of the plate 26 are separated. In the inkjet printer head 19, the electrode layer 20 located on the top surface of the piezoelectric member 22 is an individual electrode and the other electrode layer 21 is a common electrode, as shown in FIG. 3 (b). Further, the terminal portion 33 of the electrode layer 21 which is the common electrode has a shape communicating with the main scanning direction, and the terminal portion 32 of the electrode layer 20 which is the individual electrode is divided for each piezoelectric member 22.
Further, as illustrated in FIG. 2, a long groove 35 communicating from the surface to the pressure chamber 28 is formed in at least one of the two main body plates 26 in the main scanning direction, and is formed by the long groove 35. An ink tank (not shown) is connected to the ink supply path.

With this arrangement, the ink jet printer head 19 has the long groove 3 extending from the ink tank.
In the state where ink is supplied into each pressure chamber 28 in 5, the predetermined piezoelectric member 22 is expanded and contracted by selective energization,
The ink in the pressure chamber 28 facing the piezoelectric member 22 is pressurized to eject ink droplets from the orifice.

At this time, the ink jet printer head 19 has a structure in which the ink in one pressure chamber 28 is individually pressurized by one piezoelectric member 22, so that the print quality is deteriorated due to structural crosstalk. Is prevented. Further, the selective driving of the piezoelectric member 22 as described above is performed by selectively applying a low voltage to a predetermined electrode layer 20 while a high voltage is constantly applied to the electrode layer 21. In the inkjet printer head 19,
Since the electrode layers 20 and 21 of the partition walls 24 that are structurally adjacent to each other are separated from each other, deterioration of print quality due to electrical crosstalk is also prevented. That is, in such an inkjet printer head 19, the non-piezoelectric member 2
It is conceivable to omit 3 and form the partition wall 24 entirely with the piezoelectric member 22, but in this case, since the electrode layers 20 and 21 of the adjacent partition walls 24 are extremely close to each other, charge transfer occurs and driving is performed. As a result, crosstalk is generated on both sides of the piezoelectric member 22 which causes the print quality to deteriorate. Therefore, in the inkjet printer head 19 of the present invention, the electrical crosstalk is achieved by separating the electrode layers 20 and 21 so that the piezoelectric member 22 is located between the non-piezoelectric members 23 by the combination of the partition walls 24. To improve print quality. Further, in the ink jet printer head 19, since the electrical and structural crosstalk is prevented as described above, it is possible to drive the piezoelectric members 22 at the same time, and the deformation of the piezoelectric member 22 is also possible. Since it is not necessary to control the speed and the restoration speed to be different, the printing speed can be increased.

Specific examples of materials and manufacturing methods for the respective parts of the main body plate 26 of the ink jet printer head 19 will be described below. First, a step 34 is formed by cutting or the like on an insulating substrate made of a ceramic such as alumina or a resin such as polysulfone and a non-piezoelectric member such as glass, and a plate thickness of 0.05 to 1.0 (mm) and a front-rear length of 1.0 are formed on the step 34. ~ 30 (m
A piezoelectric member 22 made of PZT (Lead Zirco Titanate) of about m) is joined by an adhesive layer 31. The plate thickness of the piezoelectric member 22 is preferably 0.1 to 0.5 (mm), and its front-rear length is defined based on the required discharge characteristics, the lateral width of the pressure chamber 28, and the like.

Then, as illustrated in FIG. 3A, the insulating substrate and the piezoelectric member 22 integrally joined as described above.
And the insulating layer 30 and the electrode layer 20 are sequentially formed on the substrate and the terminal portion 32 of the electrode layer 20 is formed by patterning by photoetching. As illustrated in FIG. The partition walls 24 are formed by dividing the electrode layer 20 by forming a large number of concave grooves 27 at positions between 32 by dicing. By doing so, the electrode layer 20 has the same shape as the piezoelectric member 22 and therefore has good conductivity characteristics. In this inkjet printer head 19, an insulating layer 30 for separating the electrode layers 20 and 21 behind the piezoelectric member 22 is also provided between the piezoelectric member 22 and the electrode layer 20. It is also possible to remove the 30 from the piezoelectric member 22 by photoetching or the like and then provide the electrode layer 20 to improve the current-carrying characteristics. Similarly, a thin film adhesive layer 31 is provided between the piezoelectric member 22 and the electrode layer 21. In this case, the adhesive layer 31 is used.
It is practicable to improve the current-carrying characteristics by forming a conductive adhesive.

Here, the concave groove 27 formed by the dicing process as described above inevitably has an unnecessary radius at the rear edge thereof as illustrated in FIG. 2, but this is filled with resin or the like. Can be easily sealed with a material. It is also conceivable to use the rounded portion at the end of the concave groove 27 for the ink supply path. If the opening is too large, the piezoelectric member 22 is extended rearward to open the opening. It is possible to adjust the size. Since the electrode layers 20 and 21 are exposed close to the cut surface at the rounded portion of the concave groove 27 by the dicing process as described above, an insulating coating (not shown) is formed here to prevent discharge. It is possible to do it. In addition, such an insulating coating is used for the piezoelectric member 22.
This can be omitted by forming the wiring directly on the upper electrode layer 20 and not forming the electrode layer 20 on the rounded portion of the concave groove 27.

The two body plates 26 formed as described above are integrally joined to each other, so that the partition walls 24 are combined with each other so that the lateral width is 0.05 to 1.0 (mm) and the vertical width is 0.02 to 0.2 ( mm) pressure chambers 28 are formed. Therefore, an orifice plate having an orifice with a diameter of about 0.02 to 0.08 (mm) is integrally formed on each pressure chamber 28 on the front surface of the main body plate 26. The production of the printer head 19 is completed. In the inkjet printer head 19, there is a gap communicating with the pressure chamber 28 between the side faces of the adjacent partition walls 24, but since this gap is extremely thin and long, the pressure loss of the piezoelectric member 22 is very small.
It is also possible to fill such a gap with rubber or the like.

In the ink jet printer head 19, since the step 34 is formed at the trailing edge of the insulating substrate, the terminal portions 32 of the main body plate 26 integrally joined,
A wiring material (not shown) such as an FPC (Flexible Printed Circuit) can be easily connected to the 33. However, if the wiring material is connected before the main body plate 26 is joined, the work is extremely simple. ..

In the ink jet printer head 19 of this embodiment, the main plate 26 is integrally joined by the convex portion 29 from which the electrode layers 20 and 21 and the insulating layer 30 are removed, so that the adjacent electrode layers 20 and 21 can be completely removed. Although it is assumed that they are separated from each other, the present invention is not limited to the above structure. That is, in the inkjet printer head 19, it is sufficient that the electrode layers 20 and 21 of the adjacent partition walls 24 are separated from each other by a distance capable of ensuring insulation, so that the two main body plates 26 are integrally joined on the electrode layer 20. It is also feasible. Further, in the ink jet printer head 19 of the present embodiment, it has been illustrated that the electrode layers 21 adjacent to each other are used as the common electrode to effectively prevent the electric crosstalk, but the present invention is limited to the above-mentioned form. However, even if the electrode layer 21 is used as an individual electrode, electrical crosstalk can be substantially prevented.

[0026]

As described above, according to the present invention, a pre-polarized piezoelectric member is arranged in the pressure chamber in which the orifice and the ink supply passage communicate with each other, and the piezoelectric member is supplied from the ink supply passage and held in the pressure chamber. In an ink jet printer head configured to pressurize the ejected ink with the piezoelectric member that deforms according to the applied power and eject the ink from the orifice, a tip portion is formed by the piezoelectric member provided with electrode layers on upper and lower surfaces. Provided are two body plates in which a large number of partition walls whose end portions are formed of non-piezoelectric members are erected on a flat plate-shaped base portion, and the body plates are integrally joined to each other between the non-piezoelectric members of one partition wall. By arranging the piezoelectric members of the partition walls, the ink in one pressure chamber can be individually pressurized by one piezoelectric member, so that a printed product with structural crosstalk It is possible to prevent the deterioration of the print quality due to the electrical crosstalk because the electrode layers of the adjacent partition walls can be separated from each other, and it is possible to drive each piezoelectric member at the same time. Therefore, the printing speed can be increased, and an ink jet printer head that performs high-quality printing at high speed can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of the embodiment of the present invention taken along the line BB in FIG.

FIG. 2 is a vertical sectional side view of FIG. 1 taken along the line AA.

FIG. 3 is a plan view showing a manufacturing process of a main part.

FIG. 4 is a vertical sectional front view showing a first conventional example.

FIG. 5 is a vertical sectional front view showing a second conventional example.

[Explanation of symbols]

 19 Inkjet printer head 20, 21 Electrode layer 22 Piezoelectric member 23 Non-piezoelectric member 24 Partition wall 25 Base portion 26 Main body plate 28 Pressure chamber

Claims (1)

[Claims] 1. A pre-polarized piezoelectric member is arranged in a pressure chamber in which an orifice and an ink supply passage communicate with each other, and ink supplied from the ink supply passage and held in the pressure chamber is deformed according to an applied power. In an inkjet printer head in which pressure is applied by the piezoelectric member to eject from the orifice, the piezoelectric member having electrode layers on the upper and lower surfaces has a tip formed of a non-piezoelectric member. Provided are two body plates in which a large number of formed partition walls are erected on a flat base, and the piezoelectric members of the other partition wall are arranged between the non-piezoelectric members of one partition wall by integrally joining these body plates. An inkjet printer head characterized by the above.