Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-10-04
2004-10-12
Feggins, K. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06802598
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet head and a production method of the same.
In an ink jet head employed in ink jet printers, a method is available in which a pressure pulse is generated in the ink chamber employing a piezoelectric element, and thus ink droplets are ejected from the nozzle. In said piezoelectric element, an electrode, which applies driving voltage, is essential, and said electrode is arranged, being in direct contact with ink. When the electrode is brought into contact with a water based ink, water in the ink is subjected to electrolysis which generates bubbles, while the electrode is dissolved resulting in disconnection while running. Further, even when oil based ink is employed, carbon chains are formed from organic materials in the ink to cause short circuit. Accordingly, it is desired to protect the electrode from ink. In order to achieve this goal, it is known that various types of organic or inorganic layers are formed on the electrode.
Listed as such inorganic layers are various types of oxides and nitrides. For instance, included are silicon-oxygen (SiO), silicon-nitrogen (SiN), silicon-oxygen-nitrogen (SiON), silicon-carbon (SiC), aluminum-nitrogen (AlN), silicon-aluminum-nitrogen (SiAlN), aluminum-oxygen (AlO), aluminum-silicon-oxygen (AlSiO), and silicon-aluminum (SiAl).
Employed as organic layers are various types of polymer layers, and it is proposed to employ polyparaxylene as representative polymers.
When bubbles are mixed in an ink channel, especially in an ink chamber to which pressure is applied employing a piezoelectric element, said bubbles absorb applied pressure which decreases the speed of ejected ink or occasionally results in no ink ejection. Accordingly, in the ink jet head, it is required that the interior of the ink channel be smooth and continuous.
SUMMARY OF THE INVENTION
From the foregoing, the present invention has been achieved. It is a first object of the present invention to provide an ink jet head in which degradation of the electrode of said ink jet head is minimized. It is a second object of the present invention to provide an ink jet head comprising a layer on the electrode which is readily formed. It is a third object of the present invention to provide an ink jet head in which each member in said ink jet head is not degraded and a smooth and continuous layer, which covers the electrode, can be easily formed.
In order to solve the aforementioned problems, as well as to achieve the objects, the present invention has been embodied as described below.
(1-1) An ink-jet head, comprises:
an ink chamber in which ink is stored;
a piezoelectric element to jet the ink from the ink chamber;
an electrode to apply an electric voltage onto the piezoelectric element;
a layer provided on the electrode by an electrodeposition method, the layer subjected to a process to change a surface energy.
According to (1-1), since materials, which are deposited employing electrodeposition, generally have a functional group, it is possible to control properties of a layer by controlling the amount of said functional group or by selecting the materials used. Thus it is possible to form a desired layer with response to the characteristics of an ink jet head as well as the ink itself. Further, when a treatment is carried out to vary surface energy, it is possible to markedly enhance the wettability between the ink jet head and the ink.
Further, when a layer is formed employing an electrodeposition method (even when a protective layer is formed employing materials which are inherently hydrophilic), the surface energy increases while minimizing the solubility of said surface layer in the ink. However, this causes a problem with insufficient wettability of the ink. In order to overcome this problem, when a treatment to vary the surface energy is carried out, it is possible to increase the wettability for the ink.
(1-2) In the ink-jet head of (1-1), the process to change a surface energy is a process to increase the surface energy.
(1-3) In the ink-jet head of (1-1), the process to change a surface energy is an oxidizing process.
(1-4) In the ink-jet head of (1-3), the oxidizing process is a plasma process.
(1-5) In the ink-jet head of (1-1), the layer contains polyimide.
(1-6) In the ink-jet head of (1-1), a thickness of the layer is 0.1 &mgr;m to 50 &mgr;m.
(1-7) An ink-jet head, comprises:
an ink chamber in which ink is stored;
a piezoelectric element to jet the ink from the ink chamber;
an electrode to apply an electric voltage onto the piezoelectric element;
a layer provided on the electrode by an electrodeposition method, the layer containing polyimide.
According to (1-7), when a polyimide layer is formed by electrodepositing a polyimide precursor followed by heating the deposited layer at relatively,high temperature, there is the possibility that the piezoelectric element, having a lower heat resistance, is damaged. However, it is possible to overcome this problem as follows. When the polyimide itself is electrodeposited, it becomes unnecessary to heat the piezoelectric element to a relatively high temperature. Thus it is possible to employ a piezoelectric element having a lower heat resistance. Further, when heated to a relatively high temperature, the polyimide melts to a fluid and the polyimide layer is partially removed to form pinholes. As a result, insulation degradation tends to occur. However, when the polyimide is electrodeposited, no heating is required to a relatively high temperature. As a result, it is possible to minimize such problems.
(1-8) In the ink-jet head of (1-7), the polyimide is made from 3,5-diaminobenzoic acid.
(1-9) In the ink-jet head of (1-7), a thickness of the layer is 0.1 &mgr;m to 50 &mgr;m.
(1-10) An ink-jet head, comprises:
an ink chamber in which ink is stored;
a piezoelectric element to jet the ink from the ink chamber;
an electrode to apply an electric voltage onto the piezoelectric element;
a first layer provided on the electrode by an electrodeposition method, and
a second layer provided on the electrode.
(1-11) In the ink-jet head of (1-10), the second layer is an organic layer.
(1-12) In the ink-jet head of (1-11), the organic layer contains polyparaxylylene.
(1-13) In the ink-jet head of (1-10), the first layer contains polyimide.
(1-14) In the ink-jet head of (1-10), a thickness of the layer is 0.1 &mgr;m to 50 &mgr;m.
(1-15) In the ink-jet head of (1-10), a thickness of a composite layer of the first layer and the second layer is 0.1 &mgr;m to 50 &mgr;m
(1-16) An ink-jet head, comprises:
an ink chamber in which ink is stored;
a piezoelectric element to jet the ink from the ink chamber;
an electrode to apply an electric voltage onto the piezoelectric element;
a first layer containing polyimide provided on the electrode, and
a second layer being an organic layer provided on the electrode.
(1-17) In the ink-jet head of (1-16), a thickness of a composite layer of the first layer and the second layer is 0.1 &mgr;m to 50 &mgr;m.
(1-18) In the ink-jet head of (1-16), the organic layer contains polyparaxylylene.
According to (1-10) or (1-16), it is possible to realize an ink jet head having ink resistance as well as insulation properties.
(1-19) A method of manufacturing an ink-jet head, comprises:
a step of forming a layer by an electrodeposition method on an electrode to drive a piezoelectric element to jet an ink from an ink chamber, and
a step of applying a process to change a surface energy onto the layer.
(1-20) A method of manufacturing an ink-jet head, comprises:
a step of forming a layer containing polyimide by an electrodeposition method on an electrode to drive a piezoelectric element to jet an ink from an ink chamber.
(1-21) A method of manufacturing an ink-jet head, comprises:
a step of forming a first layer by an electrodeposition method on an electrode to drive a piezoelectric element to jet an ink from an ink chamber, and
a step of forming a second layer on the electrode.
(1-22) A method of manufacturing an ink-jet head, comprises:
a step of forming a first lay
Ito Takeshi
Nomori Hiroyuki
Watanabe Hideo
Feggins K.
Konica Corporation
Muserlian Lucas and Mercanti
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