Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-09-29
2002-08-20
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S063000
Reexamination Certificate
active
06435660
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate intended to configure an ink jet recording head (hereinafter also called an ink jet head) which performs operations, such as recording or printing characters, symbols, images, etc. by ejecting functional liquid, such as ink, against record bearing media, including paper, a plastic sheet, cloth, and an article; an ink jet head, which is configured by using the substrate; a recording unit which includes an ink reservoir for reserving ink to be fed to the ink jet head such as an ink jet pen; and an ink jet apparatus in which the ink jet head is installed.
Recording units according to the present invention, such as an ink jet pen, include those of a cartridge type into which an ink jet head and an ink reservoir are integrated and those of a combination type into which an ink jet head and an ink reservoir are combined so that the head and reservoir can be removed independently of each other. A recording unit, such as an ink jet pen, is adapted so that it can removably be attached to mounting means in an apparatus body, such as a carriage. Ink jet recording apparatuses according to the present invention include those which are provided integrally or separately as an output terminal for information processing equipment, such as word processors and computers; copying machines combined with an information reader etc., facsimile machines which send and receive information; and equipment which prints cloth.
2. Related Background Art
An ink jet recording apparatus can characteristically record a fine image fast by ejecting fine ink droplets from an ejection orifice at high speed. As disclosed in U.S. Pat. No. 4,723,129 and U.S. Pat. No. 4,740,796, ink jet recording apparatuses of such a type that ink is ejected using ink bubbling due to energy, especially thermal energy produced by an electric converter as energy producing means for producing energy used to eject ink have been the focus of attention because they can form a fine image and make a record at high speed and are suitable for reducing recording heads and recording apparatuses in size and providing color recording heads and recording apparatuses.
FIG. 1
shows a typical configuration of an ink jet head as described above.
FIG. 2
is a schematic sectional view of an ink jet recording head substrate
2000
, taken along a line
2
—
2
passing through an ink path in FIG.
1
.
In
FIG. 1
, the ink jet recording head has a plurality of ejection orifices
1001
, and an electrothermal converting element
1002
which produces thermal energy used to eject ink through the ejection orifices is provided on a substrate
1004
for each ink path
1003
.
The electrothermal converting element
1002
mainly comprises a heating resistor
1005
, electrode wiring
1006
which supplies power to a heating resistor, and insulating film
1007
which protects the resistor and wiring. The ink paths
1003
are formed by jointing together a plurality of top plates with which a path wall
1008
is integrated with, while aligning the plates with the electrothermal converting elements or the like on the substrate
1004
. Each ink path
1003
communicates at its end opposite to the ejection nozzle
1001
with a common liquid chamber
1009
, in which ink from an ink tank (not shown) is reserved. After fed to the common liquid chamber
1009
, ink is directed therefrom into each ink path
1003
and held when it forms a meniscus near the ejection nozzles
1001
. Thermal energy produced by selectively driving an electrothermal converting element
1002
is used to rapidly boil ink on a heating surface, so that ink is ejected by impulse due to boiling.
In
FIG. 2
, reference numerals
2001
and
2002
denote a silicon substrate and a heat storing layer (interlayer film) consisting of SiO
2
film (heat oxidation film), SiN film, etc. Reference numeral
2003
denotes a heater;
2004
, a heating resistor layer;
2005
, wiring made of Al, Al—Si, Al—Cu, etc.;
2006
, a least one protective layer consisting of SiO
2
film, SiN film, etc.;
2010
, a cavitation-resistant layer made of Ta film or the like, which protects the protective layer
2006
from chemical and physical impulse accompanying heat production by the heating resistor layer
2004
; and
2008
, a heating section of the heating resistor layer
2004
.
The heating section
2008
generates heat due to pulse application caused by ink bubbling, and ink on the section rapidly boils when the section reaches about 300° C. or more.
To bubble ink in such a way, the heating section is kept hot. In addition, to stabilize bubbling by inhibiting head quality variations and those in body driving, more energy than is required for ink to bubble need to be fed. As a result, the temperature of the heating section further increases. Under normal driving conditions, the temperature appears to reach 450° C. to 550° C.
Such a high temperature reached may cause a serious problem affecting the life of the head. The problem is that dye or pigment ink is exposed to high temperature, so that decomposition products produced by molecular chain cutting are deposited as “scorches” on the heating section; that is, “kogation” occurs.
Owing to this “kogation” decomposition products are gradually deposited on the heating section, finally making it difficult to make ink bubble stably, affecting head life.
To prevent this phenomenon, various measures have been taken, including modifying ink components, such dyes, and adding to ink a component which prevents scorches.
However, a variety of demands are made on an image which an ink jet printer prints by ejecting ink. For example, these demands include increasing printed matter water resistance, preventing intercolor breed, and improving wear resistance. To meet these demands, ink components must be further modified. However, such modification may neutralize the effects of thus far taken measures for preventing scorches, thus reposing the problem of scorches. The present invention intends to prevent scorch deposits on the heating section and prolong recording head life even if such ink is used.
Japanese Patent Application Laid-Open No. 11-240156 discloses that water-repellent film is formed in an area corresponding to the heating section to prevent scorches from being easily deposited on the heating section and thereby inhibit bubbling efficiency reduction so that ink can stably bubble.
Japanese Patent Application Laid-Open No. 11-42798 discloses that a liquid which is low in surface tension and volatility than ink to be ejected is introduced into an ink path to break hydrophobic film on the internal surface of the ink path before ink to be ejected is introduced into the path, thereby helping ink wet the internal surface so that ink is easily introduced into the path. However, the publication does not disclose prevention of scorch deposits on the heating section. The method disclosed in the publication is not expected to provide hydrophilicity strong enough to satisfactorily prevent scorch deposits.
“Chemistry and Industry” (No. 48, pp. 1256 to 1258, 1995) describes glass which is made hydophilic so that soil comes off spontaneously. “Chemistry and Industry” [No. 49(6), pp. 764 to 767, 1996] also describes the effect of photo catalyst.
“Applied Physics” [No. 64 (8), pp. 803 to 807, 1995] describes physical properties of material.
These descriptions relate to preventing soil deposits on a substrate surface or decomposing them by making the surface phydrophilic or forming a photo catalyst phydrophilic layer on the surface.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink jet recording head substrate, an ink jet recording head, an ink jet recording unit, and an ink jet recording apparatus which allow scorch deposits on the heating section to be prevented by exerting on the section effect of providing super-hydrophilicity, which is given by reinforcing the effect of providing hydrophilicity or effect of providing photo catalyst hydrophilicity.
It is anothe
Kanda Hidehiko
Katsuragi Ryuji
Shirota Koromo
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