Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1996-11-08
2002-04-16
Nguyen, Judy (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S050000
Reexamination Certificate
active
06371604
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink jet recording head comprising a recording element substrate and a driving element which are pressed together, wherein the recording element substrate comprises recording elements for ejecting ink, and the driving element substrate comprises driving elements for driving the recording elements in response to externally inputted image signals.
Regarding the terminology in the present invention, a word “recording” means “attaching meaningful patterns such as letters or geometrical figures to a recording medium as well as “attaching meaningless patterns to a recording medium.”
(A) The present invention is applicable to an apparatus such as a printer which records patterns on a recording medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics. It is also applicable to an apparatus such as a copying machine, a facsimile machine comprising a communication system, or a word processor comprising a printing section. Further, it is applicable to an industrial recording apparatus integrally comprising a printing section and various processing apparatuses.
FIG.
1
(
a
) is a plan view of the structure of a conventional recording element substrate of an ink jet recording head employed in an ink jet recording apparatus or the like, and FIG.
1
(
b
) is a section of the structure illustrated in FIG.
1
(
a
), at A-A
1
line.
Referring to FIGS.
1
(
a
) and
1
(
b
), a reference numeral
1501
designates a substrate on which recording elements are disposed;
1502
, a heat generating element, that is, a layer of heat generating resistor, for example, HfB
2
;
1503
, a common electrode composed of aluminum;
1504
, an individual electrode composed of aluminum;
1505
a
and
1505
b,
patterned Al wiring;
1506
, a photosensitive polyimide layer as an anti-oxidation layer as well as an insulative layer; and a reference numeral
1508
designates a Ta layer as an anti-cavitation layer.
The recording element substrate illustrated in FIGS.
1
(
a
) and
1
(
b
) generates thermal energy from the HfB
2
layer as electric current is flowed through the HfB
2
layer
1510
as a heat generating resistor layer. More specifically, in order to generate thermal energy in the heat generating element
1502
, driving current is externally flowed into the HfB
2
layer
1502
through the individual electrode
1504
and the patterned wiring
1505
a,
and is flowed out through the patterned wiring
1505
b
and the common electrode
1503
.
(B)
FIG. 2
illustrates the structure of a recording element unit employing the recording element substrate described above. This recording element unit is provided with ink paths
1520
which lead to corresponding ejection orifices
1521
. In each ink path
1520
, a heating element is disposed. Ink is supplied into a liquid chamber
1530
through an ink supply port (unillustrated) of a top plate
1540
, and is delivered to the ink path
1520
from the liquid chamber
1530
.
As a driving signal is given to the heating element, a bubble is developed in the ink in the ink path, whereby the ink is ejected from the ejection orifice
1521
.
Normally, a plurality of the heat generating elements
1502
, which are constituted of a combination of the HfB
2
1510
, the dedicated electrode
1504
, the patterned wiring
1505
a,
and the patterned wiring
1505
b,
are disposed on a single recording substrate. Deposing a plurality of heat generating elements on a single recording element substrate makes it possible to realize an ink jet recording apparatus capable of printing a plurality of dots at the same time, increasing recording speed. In particular, in the present situation in which demands for high density and high recording speed are rather high, it is quite common that a plurality of lines are recorded at the same time through a single scanning pass, and also, a recording element unit in which a large number of heat generating elements are disposed in high density is very common.
In order to record a plurality of dots by disposing a plurality of recording elements in a single recording unit, each recording element must be independently controlled (turned on or off). Such control is possible by providing the recording element unit with a means for selectively driving each of the heat generating elements (hereinafter, driving element). However, in the case of a long recording unit, that is, a recording unit comprising a large number of heat generating elements, the driving means is formed on a separate substrate (hereinafter, driving element substrate), and is connected to the recording unit. The reason for rendering the recording element unit and the driving element substrate independent from each other is due to the problem that when the recording element and the driving element are disposed on the same substrate, presence of a defect in either the recording element or the driving element causes the entire unit to stop functioning.
As for the technology (method) for electrically connecting the recording element substrate to the driving element substrate, there is a method disclosed in U.S. Pat. No. 5,243,363.
According to the aforementioned connecting method, a structure substantially the same as the structure illustrated in FIGS.
1
(
a
) and
1
(
b
) is employed. More specifically, a bump-like portion is formed on each of the dedicated electrodes, and, a recording element substrate
7001
attached to the main base board
7005
is joined with the driving element substrate
7002
having a driving IC
7003
, by the application of pressure.
Japanese Laid-Open Patent Application No. 302,829/1989 discloses a different method which employs an electrical connecting member. FIGS.
4
(
a
)-
4
(
c
) depict the connecting method disclosed the above patent application.
In
FIG. 4
, a reference numeral
1704
designates a recording element substrate;
1705
, a driving element substrate;
1714
and
1715
, electrode portions; and reference numerals
1719
and
1720
designate insulative film. Further, a reference numeral
1703
designates an electrically connective member;
1717
, an electrically conductive member; and a reference numeral
1718
designates a supportive member for supporting the electrically conductive member
1717
. The pitch of the electrically conductive member
1717
is narrower than those of the electrodes
1714
and
1715
.
First, the recording element substrate
1704
, driving element substrate
1705
, and electrically connective member
1703
are arranged as shown in FIG.
4
(
a
), and then, are pressed together as shown in FIG.
4
(
b
). FIG.
4
(
c
) gives the overall appearance of the joined three members. Since the pitch of the electrically conductive member
1717
is smaller than those of the electrodes
1714
and
1715
, it is unnecessary to precisely position them; the electrodes
1714
and
1715
can be electrically connected through the electrically conductive member
1717
, simply by pressing them together.
FIGS. 5 and 6
illustrate an example of a recording head constituted of a recording element and a separate driving element substrate.
FIG. 5
is a perspective view of the recording head, and
FIG. 6
is a section thereof, as seen from the direction indicated by an arrow mark in FIG.
5
.
In the recording head illustrated in
FIGS. 5 and 6
, a recording element substrate
8001
and a driving element substrate
8002
are fixed to a main base board
8005
and an auxiliary substrate
8004
, respectively. A filter for removing the bubbles and foreign matter within the recording liquid is fixed to the main base board
8005
.
As for the method for electrically connecting the recording element substrate
8001
and the driving element substrate
8002
, first, the connective electrode of the driving element substrate
8002
is accurately positioned relative to the connective electrode of the recording element substrate
8001
, and the, the auxiliary base board
8004
is pressed toward the main base board by the pressing plate
8007
, with an elastic member
Hirosawa Toshiaki
Yamane Toru
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