JP2000079685A - Line head for ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high speed high image quality line head realizing high density high image quality print of multicolor (more than five colors) ink in which high productivity can be attained through a simple structure. SOLUTION: The line head comprises an ink nozzle 5, an ink passage 6, an ink chamber 7, and a ferroelectric piezoelectric element 4 for ejecting ink from the ink nozzle through the ink passage by varying the volume of the ink chamber wherein a silicon substrate 1 is employed for forming the ink nozzle and the ink passage. A ferroelectric thin film of the ferroelectric piezoelectric element is formed by introducing a photosensitive group to a ferroelectric precursor sol formed by sol-gel method, applying the precursor sol to a basic material and fine patterning a ferroelectric gel thin film thus obtained by optical fabrication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line head for an ink jet printer, and more particularly, to a piezoelectric actuator that changes the volume of an ink chamber filled with ink, and at this time, ejects ink from an ink nozzle through an ink path. The present invention relates to a line head of an ink jet printer that performs desired printing according to the present invention, and this line head is used by being built in an ink jet printer such as a word processor, a facsimile, and a plotter.

[0002]

2. Description of the Related Art In a printer such as a word processor, a facsimile or a plotter, an ink jet printer using a piezoelectric actuator has been put into practical use, and there are several types of printers.

As one system of an ink jet printer, for example, US Pat. No. 4,189,734 and US Pat.
A Kaiser method disclosed in, for example, Japanese Patent No. 16483 is known. This Kaiser type printer head is generally configured as follows. That is, on the base of the printer head, an individual ink path branching from the common ink path is provided toward the ejection nozzle. Further, a diaphragm is attached to the base of the printer head so as to cover the individual ink path, and the diaphragm is flexed and vibrated to change the volume of the individual ink path so that the vibration is changed for each vibration of the diaphragm. Ink is ejected toward the paper. Then, in order to apply a vibration driving force to the vibration plate, a piezoelectric element is fixed to the vibration plate at a position corresponding to the individual ink path, and by applying a voltage to a desired selected piezoelectric element, the piezoelectric element is moved. By displacing the diaphragm, the diaphragm at that portion is vibrated.
As a result, the volume of the individual ink path corresponding to the vibration of the diaphragm changes, as described above, so that the ink can be pushed out from the ejection nozzle.

Such a Kaiser type ink jet printer is disclosed in, for example, JP-A-63-252750 and JP-A-63-247051, and corresponding US Pat. Nos. 4,879,568 and 488710.
No. 0, No. 4992808, No. 500
Various further improvements have been made as disclosed in, for example, US Pat. Nos. 3,679 and 5,028,936. It is alleged that these improved printer heads can operate at low energy and provide an ink jet printer with a high ink ejection density.

[0005]

However, in recent ink-jet printers, the required printing speed and image quality are further increased, and the above-mentioned ordinary Kaiser type line head is required to have such a high speed. It is also very difficult to deal with high image quality.
That is, in the related art, there is a limit in the fine processing of the ink head, and it is very difficult to further increase the pitch and size of the ink nozzles and ink paths.

[0006] Further, with the conventional technique, fine processing of the ferroelectric piezoelectric element cannot be performed. Further, in the related art, since the number of nozzles is small, reproducibility of a document image is poor.

At present, from the above circumstances, it is difficult to increase the number of colors to five or more according to the prior art. Further, with a line head manufactured by the conventional technique, it is very difficult to achieve high speed and high image quality. That is, if a line head for an ink-jet printer by high-definition processing can be provided, multicolor printing can be performed, and high-speed printing can be performed as well as faithful reproduction of a document image.

Accordingly, an object of the present invention is to realize high-density and high-quality printing, to achieve a simple structure and high productivity, and to obtain multicolor (five or more) inks. An object of the present invention is to provide a line head of an ink jet printer capable of performing high-speed printing and high-quality printing.

[0009]

The invention according to claim 1 is
A plurality of ink nozzles, an ink path individually connected to each of the ink nozzles, and an ink chamber individually connected to each of the ink paths. In a line head of an ink jet printer having a ferroelectric piezoelectric element for ejecting ink from the ink nozzle through a passage, a silicon substrate is used as a substrate on which the ink nozzle and the ink passage are formed. And

According to a second aspect of the present invention, in the line head according to the first aspect, the ink nozzles and the ink paths on the substrate are finely processed by using a silicon plasma etching method, which is an integrated circuit design technique. And

According to a third aspect of the present invention, there is provided an ink jet printer having a plurality of ink nozzles, ink paths individually connected to the respective ink nozzles, and ink chambers individually connected to the respective ink paths. In a line head of an ink jet printer having a ferroelectric piezoelectric element for individually changing the volume of a chamber and ejecting ink from the ink nozzle through the ink path, a ferroelectric thin film of the ferroelectric piezoelectric element However, a photosensitive group is introduced into a ferroelectric precursor sol formed by a sol-gel method, and the precursor sol is applied to a substrate, and a ferroelectric gel thin film obtained is finely patterned by optical fabrication. It is characterized by being formed.

In the line head of the ink jet printer according to the first aspect of the present invention, micromachining of an anisotropic silicon substrate can be performed, and fine processing of ink nozzles and ink paths formed on the substrate can be performed. Become. In the line head according to the third aspect of the present invention, fine patterning of a ferroelectric thin film becomes possible with introduction of a photosensitive group into a sol of a ferroelectric precursor derived from a sol-gel method. Fine processing of the element becomes possible.

As described above, in comparison with the line head of the ink jet printer which can be manufactured by using the prior art, the line head according to the present invention has a high precision processing of the ink head portion (reduction of the nozzle shape, reduction of the nozzle pitch). Miniaturization, ink path miniaturization, etc.)
Multicoloring is possible due to the fine patterning of the ferroelectric thin film of the ferroelectric piezoelectric element that controls the ink head part,
Not only faithful reproduction of the original image but also high-speed printing is possible.

[0014]

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

FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a partially enlarged longitudinal sectional view of a line head of an ink jet printer, and FIG. FIG. 3 is an overall plan view of the line head as viewed from the ink nozzle side, and FIG. 4 is an overall plan view of the line head as viewed from the piezoelectric element side. It is a top view. However, FIG. 4 shows a plan view with the ink tank removed, and the illustration of the piezoelectric element is omitted.

The line head of this ink jet printer is configured by bonding a silicon substrate 1 and an inorganic thin film substrate 2 made of zirconia, silicon or the like, and providing a ferroelectric piezoelectric element 4 on the inorganic thin film substrate 2 side. . Inorganic thin film substrate 2
Is formed by bonding a plurality of thin plates, and one thin plate in contact with the ferroelectric piezoelectric element 4 becomes the diaphragm 3.
A large number of ink nozzles 5 are formed in the silicon substrate 1, and ink paths 6 individually communicating with the respective ink nozzles 5 are formed in the silicon substrate 1. The pitch of the ink nozzles 5 is, for example, about 20 μm. In the inorganic thin film substrate 2, ink chambers 7 individually communicating with the respective ink paths 6 are formed. Further, an ink supply port 11 is formed in the inorganic thin film substrate 2, and the ink supply port 11 and the ink chamber 7 are provided in the silicon substrate 1.
And an ink passage 12 that communicates with the ink passage.

An ink tank 13 is mounted on the inorganic thin film substrate 2 so as to cover the entire surface thereof. Ink is supplied from the ink tank 13 to the ink supply port 11, and the ink passes through the ink passage 12 and passes through the ink chamber 12. 7 is introduced. The ink tank 13 is formed in a rod shape as shown by a two-dot chain line in FIG. 4, and ink tanks for respective colors, for example, a cyan ink tank 13a, a yellow ink tank 13b, a magenta ink tank 13
c, a large number of five color ink tanks of a light cyan ink tank 13d and a light magenta ink tank 13e are arranged in one direction, and the inorganic thin film substrate 2
Cover the side.

The ferroelectric piezoelectric element 4 has a structure in which an upper electrode pattern 9 and a lower electrode pattern 10 are formed on both sides of a ferroelectric layer 8. The arrangement pitch of the ferroelectric piezoelectric elements 4 is equal to the pitch of the ink nozzles 5, for example, 20.
It is about μm.

The silicon substrate 1 is formed by laminating a plurality of thin plates produced by plasma etching. On the other hand, the ferroelectric piezoelectric element 4 has a ferroelectric layer 8 in which a ferroelectric gel thin film formed by a sol-gel method is finely patterned by optical fabrication between an upper electrode pattern 9 and a lower electrode pattern 10. It is formed so as to sandwich it.

The following three methods are favorably used for optical fabrication of a ferroelectric gel thin film. The first method is to impart photosensitivity to a ferroelectric precursor sol and a binder, apply a coating solution (photosensitive paste) containing both to a substrate, and then expose the coating film through a photomask,
The pattern is formed by removing an unexposed portion of the coating film using a developer. The second method is a method of forming a polymer coating film or a partially crystallized gel film as a protective film on a ferroelectric precursor gel film, and performing patterning using special development with water or the like. A third method is to prepare a pattern from a dry film in advance, and then cast a ferroelectric precursor sol into the pattern to form a pattern. The method involves controlling the wettability of the pattern surface of the dry film. To form a fine pattern.

Regarding the method of manufacturing the ferroelectric piezoelectric element 4,
PZT (lead zirconate titanate: P
This will be specifically described by taking an example in which b (Zr, Ti) O ₃ ) is used. First, a photosensitive paste having a thickness of 10 μm was applied to a substrate on which a platinum (Pt) electrode was patterned, and was dried at a temperature of 100 ° C. for 30 minutes.
This photosensitive paste is, for example, 7.5 parts by weight of hydroxypropylcellulose (HPC-L) manufactured by Nippon Soda Co., Ltd. as a photopolymerizable binder, and is manufactured by Kyoeisha Chemical Co., Ltd. as a photopolymerizable monomer. Polyethylene glycol dimethacrylate 14EG: 2.5 parts by weight, polyethylene glycol dimethacrylate 9E manufactured by the company
G: 2.5 parts by weight and pentaerythritol triacrylate manufactured by the company: 2.5 parts by weight, and as a photopolymerization initiator, for example, Cure 1800 manufactured by Ciba Geigy Corporation:
0.9 parts by weight, and further, 85 parts by weight of PZT-05L and 30 parts by weight of ethyl cellosolve (solvent) manufactured by Kyoto Elex Co., Ltd. Regarding the exposure and development, through a mask pattern, for example, 30 mW / c using a mask aligner manufactured by Mikasa Corporation.
After exposure for 1 minute at m ² , immersion development was performed for 1 minute with distilled water. As a result, a patterning result having a line width of 1 μm to 150 μm was obtained. This substrate was fired to obtain a patterned PZT piezoelectric element.

When a photosensitive group is introduced into a hydroxyl group or the like of a ferroelectric precursor sol to enable photo-patterning, for example, PZT-05L manufactured by Kyoto Elex Co., Ltd. as a photosensitive paste: 65 weight Division and PZT
Using a precursor sol: 25 parts by weight, a PZT piezoelectric element having a predetermined pattern was produced by the same procedure as described above. The ferroelectric precursor sol used at this time was
For example, it is prepared by the following method.

A magnetic stirrer is placed in a 2 liter four-necked round bottom flask equipped with a drying tube, a Dimroth condenser, a thermometer and a septum made of silicone rubber. 0.1 mol (28.42 g) of tetraisopropoxy titanium is dispensed into a flask and dissolved in 500 ml of dehydrated isopropyl alcohol. Into another container, 0.1 mol (1.80 g) of 0.001N hydrochloric acid solution is taken, diluted with 500 ml of dehydrated isopropyl alcohol, and the obtained solution is put into a flask using a micro tube pump. Drip. The drop speed at this time is 4 m
about 1 / min. After mixing the solution in the flask, the mixed solution is refluxed for 8 hours by heating using an oil bath, and the solution is naturally cooled after the reflux. The obtained solution is referred to as “solution A”.

A magnetic stirrer is placed in a 2 liter four-necked round bottom flask equipped with a drying tube, a Dimroth condenser, a thermometer and a septum made of silicone rubber. In a flask, 0.1 mol (38.37 g) of tetranormal butoxyzirconium was taken and placed in a flask.
Dissolve in ml of dehydrated isopropyl alcohol. Also, 0.2 mol (20.02 g) of acetylacetone was dissolved in 100 ml of dehydrated isopropyl alcohol,
This solution is added to the tetranormal butoxyzirconium solution in the flask, and the mixed solution is stirred. Then, by heating using an oil bath, the mixed solution is refluxed for one hour, and after the reflux, the solution is naturally cooled.

In a separate container, 0.1 mol (1.80 g) of 0.001N aqueous hydrochloric acid was taken, diluted with 500 ml of dehydrated isopropyl alcohol, and the obtained solution was transferred using a microtube pump. Drop into flask. The dropping speed at this time is about 4 ml / min. After mixing the solution in the flask, the mixed solution is refluxed for 8 hours by heating using an oil bath, and the solution is naturally cooled after the reflux. Let the obtained solution be B liquid.

A solution of 0.033 mol (0.60 g) of 0.001 N hydrochloric acid in water is diluted with 150 ml of dehydrated isopropyl alcohol, and the obtained solution is dropped into the solution A using a microtube pump. The drop speed at this time is 4 m
about 1 / min. The mixed solution is stirred at room temperature for 30 minutes. The resulting solution is designated as solution C.

The solution B is added to the solution C, and the mixed solution is refluxed for 2 hours by heating using an oil bath. After the reflux, the solution is cooled naturally. The resulting solution is designated as solution D.

Pb2-aminoethoxy-acetate [P
b (NH₂CH₂CH₂O) (CH ₃COO)] 0.2
Mole (65.26 g) in 200 ml of dehydrated isopropyl
Dissolve in alcohol and add the resulting solution to solution D
You. Mixing solution for 2 hours by heating using oil bath
Reflux and allow the solution to cool after reflux.

Thereafter, the obtained solution is concentrated to a predetermined concentration at a temperature of 70 ° C. or less using a rotary evaporator. Thus, a PZT precursor sol was obtained.

When comparing the number of ink nozzles in the line head according to the prior art with the number of ink nozzles in the line head according to the present invention, for example, the number is 6 / head in the case of the prior art (chemical etching). In the case of using the processing technology (plasma etching technology) in the present invention, the number is 30 / head. In addition, PZT for the case according to the prior art and the case according to the technology of the present invention.
Comparing the L / S (line / space) in the patterning of, for example, the PZT paste according to the prior art is 300 μm L / S, while the sol-gel PZT + photosensitive material according to the present invention is 20 μm L / S. / S.

[0031]

According to the line head of the ink jet printer according to the first aspect of the present invention, fine processing of ink nozzles and ink paths can be performed, and the line head according to the third aspect of the present invention has a ferroelectric thin film. According to the present invention, it is possible to manufacture a high-definition line head, and it is possible to perform high-speed and high-quality ink jet printing. Expression printers can be provided.

[Brief description of the drawings]

FIG. 1 is a partially enlarged longitudinal sectional view of a line head of an ink jet printer according to an embodiment of the present invention.

FIG. 2 is a partially enlarged plan view of the line head shown in FIG. 1 as viewed from a surface on a piezoelectric element side (an upper surface side in FIG. 1).

FIG. 3 is an overall plan view of the line head shown in FIG. 1 as viewed from a surface on an ink nozzle side.

FIG. 4 is an overall plan view of the line head shown in FIG. 1 as viewed from a surface on a piezoelectric element side.

[Explanation of symbols]

 Reference Signs List 1 silicon substrate 2 inorganic thin film substrate 3 diaphragm 4 ferroelectric piezoelectric element 5 ink nozzle 6 ink path 7 ink chamber 8 ferroelectric layer 9 upper electrode pattern 10 lower electrode pattern 11 ink supply port 12 ink path 12 13 ink tank

Claims (3)

[Claims] 1. An ink supply system comprising: a plurality of ink nozzles; an ink path individually connected to each of the ink nozzles; and an ink chamber individually connected to each of the ink paths. In a line head of an ink jet printer provided with a ferroelectric piezoelectric element for ejecting ink from the ink nozzle through the ink path, a silicon substrate is used as a substrate on which the ink nozzle and the ink path are formed. A line head of an ink-jet printer characterized by the following. 2. The line head of an ink-jet printer according to claim 1, wherein the ink nozzles and the ink paths on the substrate are finely processed by using a silicon plasma etching method. 3. A plurality of ink nozzles, an ink path individually connected to each ink nozzle, and an ink chamber individually connected to each ink path, wherein the volume of each ink chamber is individually set. Wherein the ferroelectric thin film of the ferroelectric piezoelectric element is formed by a sol-gel method. Photosensitive groups are introduced into the ferroelectric precursor sol formed in step 1. The ferroelectric gel thin film obtained by applying the precursor sol to the substrate is finely patterned by optical fabrication. Line head of an ink jet printer.