Reexamination Certificate
1997-08-12
2003-03-04
Barlow, John (Department: 2853)
Reexamination Certificate
active
06527813
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate that constitutes an ink jet head (hereinafter, simply referred to as an ink jet head) for discharging functional liquid, such as ink, onto recording media including paper sheet, plastic sheet, cloth, commodity, and the like, to record and print characters, symbols, images, and the like, while executing related operations. The invention also relates to an ink jet head formed by use of this substrate, and an ink jet pen that includes an ink reservoir unit to retain ink to be supplied to the ink jet head, as well as an ink jet apparatus having the ink jet head mounted on it.
In this respect, the ink jet pen referred to in the description of the present invention means to include a cartridge mode where the ink jet head and the ink reservoir unit are integrally formed, and a mode where the ink jet head and the ink reservoir unit are formed separately and detachably combined for use. The ink jet pen is structured to be detachably mountable on mounting means of the carriage or the like on the apparatus main body side.
Also, the ink jet recording apparatus referred to in the description of the present invention means to include a mode where it is formed integrally with or separately from a word processor, a computer, or some other information processing apparatus as its output device, and various modes where it operates as a copying system being combined with an information reader or the like, as a facsimile equipment having the functions of receiving and transmitting information, as a textile printing machine, or the like.
2. Related Background Art
An ink jet recording apparatus of the kind is characterized in that it discharges ink from the discharge opening as fine droplets for recording highly precise images at high speeds. Particularly, the ink jet recording apparatus of the type that it uses electrothermal transducing devices as energy generating means for generating energy to be utilized for discharging ink has, in recent years, attracted more attention, because it operates more suitably for recording images in higher precision at higher speeds, while making the recording head and apparatuses smaller, and also, making them more suitable for recording in colors. (For example, refer to the specifications of U.S. Pat. Nos. 4,723,129 and 4,740,796.)
FIG. 1
is a view which shows the general structure of the principal part of the head substrate used for an ink jet recording head described above.
FIG. 2
is a cross-sectional view which schematically shows the ink jet recording head substrate
2000
on the part corresponding to the ink flow path, taken along line
2
—
2
in FIG.
1
.
In
FIG. 1
, the ink jet recording head is provided with a plurality of discharge openings
1001
. Also, on the substrate
1004
, the electrothermal transducing devices
1002
that generate thermal energy to be utilized for discharging ink from these openings are arranged for each ink flow path
1003
, respectively. Each of the electrothermal transducing devices is formed mainly by the heat generating member
1005
, the electrode wiring
1006
that supplies electric power to it, and an insulation film
1007
that protects them.
Also, each of the ink flow paths
1003
is formed by a ceiling plate having a plurality of flow path walls
1008
, which is adhesively bonded, while its relative positions to the electrothermal transducing devices and others on the substrate
1004
are adjusted by means of image processing or the like. The end of each of the ink flow paths
1003
on the side opposite to the discharge opening
1001
is conductively connected with a common liquid chamber
1009
. In this common liquid chamber
1009
, ink supplied from an ink tank (not shown) is retained.
Ink supplied to the common liquid chamber
1009
is conducted to each of the ink flow paths
1003
from the chamber, and it is held in the vicinity of each discharge opening by means of meniscus that ink forms in such portion. At this juncture, when the electrothermal transducing devices are selectively driven, ink on the heat activation surface is abruptly heated to bring about film boiling by the utilization of thermal energy thus generated. Ink is discharged by means of its impulsive force at that time.
In
FIG. 2
, a reference numeral
2001
designates a silicon substrate, and
2002
, a heat accumulation layer.
A reference numeral
2003
designates a SiO film that dually functions to accumulate heat;
1004
, a heat generating resistive layer;
2005
, a metal wiring formed by Al, Al—Si, Al—Cu, or the like; and
2006
, a protection layer formed by SiO film, SiN film, or the like. Also, a reference numeral
2007
designates a anti-cavitation film that protects the protection film
2006
from the chemical and physical shock following the heat generation of the heat generating resistive layer
2004
, and
2008
, the heat activating portion of the heat generating resistive layer
2004
.
For the heat generating member used for the recording head of an ink jet recording apparatus, it is required to provide the following characteristics:
(1) As a heat generating member, it should have an excellent capability of responding to heat, thus making it possible to discharge ink instantaneously.
(2) It has a smaller amount of change in resistance values with respect to the high speed and continuous driving, thus presenting a stabilized state of ink foaming.
(3) It has an excellent capability of heat resistance and heat response, as well as a longer life with high reliability.
There is disclosed in Japanese Patent Application Laid-Open No. 7-125218, a structure that uses TaN film for the material of a heat generating member as the one for an ink jet head that satisfies these requirements. The characteristic stability of the TaN film (that is, the ratio of resistance changes, in particular, when recording is repeated for a long time) is closely correlated with the composition of the TaN film. Particularly, the heat generating member formed by tantalum nitride containing TaN
0.8hex
has a smaller ratio of resistance changes when recording is repeated for a long time, and presents an excellent stability of discharges.
Incidentally, besides the ink jet recording head that uses such heat generating member, there is a thermal printing head that also uses a heat generating member to be directly in contact with a thermo-sensitive sheet or an ink ribbon for recording.
As the heat generating member for such a thermal printing head, there is, for example, the one which is disclosed in the specification of Japanese Patent Application Laid-Open No. 53-25442. This head has an excellent life characteristic as a heat generating member when it operates to generate heat at high temperature. This member is formed by at least one kind of the first element selected from among Ti, Zr, Hf, V, Nb, Ta, W, and Mo; by the second element of N, and by the third element of Si, while being composed by the first element at 5 to 40 atomic %; the second element, at 30 to 60 atomic %; and the third element, at 30 to 60 atomic %. Or as disclosed in the specification of Japanese Patent Application Laid-Open No. 61-100476, there is one heat generating member having highly thermal stability and excellent printing quality, which is formed by an alloy of tantalum, high fusion point metal (such as Ti, Zr, Hf, V, Nb, Cr, Mo, or W) and nitrogen. Further, as disclosed in the specification of Japanese Patent Application Laid-Open No. 56-89578, there is a thermal head that uses a heat generating member having an excellent acid-proof capability and stability of resistance values, which contains the metal that forms nitride, silicon, and nitrogen. Also, as disclosed in the specification of Japanese Patent Publication No. 2-6201, there is a thermal head using Ta—Si—O thin film as the heat generating member, which has durability against high speed recording as well as against the use that requires a long life of the member.
At present, however, HfB
2
, TaN, TaAl or TaSi is used as material for the h
Imanaka Yoshiyuki
Miyakoshi Toshimori
Mochizuki Muga
Ogawa Masahiko
Ozaki Teruo
Barlow John
Brooke Michael S.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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