Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-07-09
2003-08-26
Nghiem, Michael (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06609782
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid jet recording head for ejecting a recording liquid in the form of droplets through minute ejection orifices, thereby recording an image on a recording medium, and a method of manufacturing the liquid jet recording head.
2. Description of the Related Art
A liquid jet recording apparatus is one of the so-called non-impact type recording apparatuses, and has the features that it is capable of recording an image on various types of recording media at a high speed, and hardly generates noise during the recording. Because of those features, the liquid jet recording apparatus has been widely employed as a recording mechanism in printers, word processors, facsimiles, copying machines, etc.
As a typical example of liquid jet recording techniques for use in that type of liquid jet recording apparatus, there is known one using an electrothermal transducer as an ejection energy generating element. According to this technique, droplets of a recording liquid are ejected through minute ejection orifices to record an image on a recording medium. A liquid jet recording apparatus employing such a technique comprises, generally, a recording head including ejection nozzles to form droplets, and a recording liquid supply system for supplying a recording liquid to the recording head. A liquid jet recording head using electrothermal transducers is constructed such that the electrothermal transducers are arranged in a pressurized chamber, an electrical pulse representing a recording signal is applied to each of the electrothermal transducers for giving thermal energy to a recording liquid, and droplets of the recording liquid are ejected by utilizing bubble pressure resulting from bubbling (boiling) of the recording liquid, which is produced as a result of a phase change of the recording liquid caused upon application of the thermal energy.
Furthermore, the liquid jet recording head using electrothermal transducers is divided into two types, i.e., one (edge shooter type) wherein the recording liquid is ejected parallel to the board on which the electrothermal transducers are arranged, and the other (side shooter type) wherein the recording liquid is ejected perpendicular to the board on which the electrothermal transducers are arranged.
FIG. 11
(consisting actually of
FIGS. 11A
,
11
B and
11
C) shows a conventional typical board (referred to as a “recording element substrate” hereinafter) on which electrothermal transducers are arranged and which has the function of ejecting a recording liquid. Specifically,
FIG. 11A
is a plan view,
FIG. 11B
is a bottom view, and
FIG. 11C
is a side view.
FIG. 12
shows the recording element substrate of
FIG. 11
connected to a wiring board.
As shown in
FIGS. 11A
to
11
C, a recording element substrate
101
has a through hole (recording liquid supply port)
103
formed therein for supply of a recording liquid from the rear surface side of the board
101
. A plurality of electrothermal transducers (not shown) for applying ejection energy to the recording liquid are arranged on the surface of a substrate
102
on both sides of the through hole
103
. Further, an ejection plate
105
is disposed on the substrate
102
, and a plurality of ejection orifices
106
are formed in the ejection plate
105
opposite to the plurality of electrothermal transducers in a one-to-one relation. A plurality of electrodes
107
are provided on the surface of the substrate
102
at both ends thereof for electrical connection to the plurality of electrothermal transducers.
Also, as shown in
FIG. 12
, a recording element unit
120
is constructed such that the plurality of electrodes
107
provided on the recording element substrate
101
and a plurality of electrode leads
113
provided on a flexible film member
111
are electrically connected to each other by the TAB technique, for example. These electrical connection areas are each entirely coated by a sealing resin
119
for protection against corrosion caused by the recording liquid and breakage of wires due to externally acting forces.
FIG. 13
is an external appearance perspective view showing one structural example of a conventional liquid jet recording head in which the recording element unit of
FIG. 12
is incorporated.
European Patent Application Laid-Open Publication No. EP0822078A2 shows a liquid jet recording head which is one example of the conventional liquid jet recording head, shown in
FIG. 13
, in which the recording element unit of
FIG. 12
is incorporated.
FIG. 14
is a partial enlarged sectional view, taken along line A—A in
FIG. 13
, of the liquid jet recording head of that Publication.
In the liquid jet recording head disclosed in that Publication, as shown in
FIGS. 13 and 14
, the recording element unit is fixedly bonded to an upper surface of a support member
108
by a bonding resin A
121
. Further, a support plate
109
is fixedly bonded to the upper surface of the support member
108
by a bonding resin B
122
, and the flexible film member
111
is fixedly bonded to an upper surface of the support plate
109
by a bonding resin C
123
. Also, a second wiring board
116
is held on and fixed to a lateral surface of the support member
108
, and an external input pad
115
for applying an electrical signal, such as recording information, to the liquid jet recording head from the body side of a recording apparatus is provided on the second wiring board
116
. The second wiring board
116
is electrically connected to a plurality of recording element units through flexible film members
111
a
,
111
b
,
111
c
and
111
d.
Thus, in the liquid jet recording head of European Patent Application Laid-Open Publication No. EP0822078A2, the recording element substrate and the wiring board are electrically connected to each other by leads, and a second sealing resin is applied to an electrical connection area between both the boards. Then, the recording element substrate is fixedly joined to the support member, the wiring board is fixedly bonded to the support plate, and a first sealing resin is filled into a recess formed between the support plate and the recording element substrate. Stated otherwise, since the first sealing resin is filled into the recess formed between the support plate and the recording element substrate in a state where the second sealing resin has been applied to the electrical connection area between the recording element substrate and the wiring board, a hollow space often occurs below the electrical connection area. In such a case, the recording liquid may enter the hollow space and corrode wires formed on the flexible film member
111
.
In view of the above problem, U.S. patent application Ser. No. 09/488,931 proposes a method of employing a thermosetting material as the first sealing resin, and very reliably filling the first sealing resin, under heating, into a space below the electrical connection area to which the second sealing resin has been applied. This invention utilizes the property of the thermosetting material that it has a higher fluidity in an initial state of the heating and is then hardened.
Also, in a liquid jet recording head disclosed in that U.S. patent application, materials having substantially the same components are used as the first sealing resin filled into the space around the recording element substrate
101
and the second sealing resin sealing the electrical connection area between the recording element substrate
101
and the wiring board
111
. The first sealing resin and the second sealing resin are heated and hardened in the same step. Because the material selected for sealing the electrical connection area between the recording element substrate
101
and the wiring board
111
is required to become very hard after hardening, for protection against external forces, a material containing an epoxy resin as a main ingredient is used for both the first and second sealing resins.
SUMMARY OF THE INVENTION
However, the recording element substrate
1
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