Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-06-03
2001-08-07
Fuller, Benjamin R. (Department: 2855)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S068000
Reexamination Certificate
active
06270193
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ink-jet recording apparatus for performing printing on an objective print medium by utilizing displacement of piezoelectric elements to discharge ink droplets from nozzles.
DESCRIPTION OF THE RELATED ART
An ink-jet head, which is included in a conventional ink-jet recording apparatus, is shown in FIG.
18
. As shown in
FIG. 18
, a plurality of electrodes (hereinafter abbreviated as “head electrode”)
82
, which are connected to a plurality of piezoelectric elements for constructing the ink-jet head
80
, are formed on both side surfaces of the ink-jet head
80
. Flexible printed circuit boards (hereinafter abbreviated-as “FPC”)
84
are electrically connected to the respective electrodes
82
. A driver IC chip-on-board (hereinafter referred to as “COB”)
88
, on which a driver IC chip
86
is carried, is electrically connected to FPC
84
. The driver IC chip
86
is electrically connected to an unillustrated control circuit through electrodes
90
. Namely, when the ink-jet head
80
is installed to the ink-jet recording apparatus, the electrodes
90
are connected to electrodes for mating with the electrodes
90
respectively, and thus the driver IC chip
86
electrically communicates with the control circuit.
The driver IC chip
86
outputs driving signals to the respective piezoelectric elements in accordance with the timing of input of a control signal outputted from the control circuit. Ink contained in an ink chamber is pressurized in response to displacement of the piezoelectric elements, and ink droplets are discharged from nozzles
81
. Thus, printing is performed on an objective print medium.
The printing is performed by simultaneously driving the many piezoelectric elements at a short interval to discharge ink droplets from the nozzles
81
. During this process, electric power loss occurs in the driver IC chip
86
. For this reason, the driver IC chip
86
reaches a high temperature in a short period of time.
However, in the case of the conventional ink-jet head
80
described above, the driver IC chip
86
is carried on COB
88
. The heat of the driver IC chip
86
is radiated in accordance with natural cooling based on contact with the outside air. Accordingly, it is impossible to obtain a sufficient heat radiation effect. Therefore, a problem arises in that the driver IC chip
86
may be possibly damaged due to overheat.
Especially, in the case of recent ink-jet recording apparatuses, printing is performed at an increasingly high resolution, the number of simultaneously driven nozzles is increased, and the driving interval is shortened. For these reasons, a much larger driving voltage is concentrated on the driver IC chip, and the driver IC chip inevitably has a high temperature. Therefore, it is an object to improve the heat radiation efficiency of the driver IC chip.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an ink-jet head which makes it possible to improve the heat radiation efficiency of an IC chip used for operating a driving circuit for piezoelectric elements accommodated in the ink-jet head, and an ink-jet recording apparatus including the ink-jet head.
Another object of the present invention is to provide a method for installing an IC chip to an ink-jet head without damaging the IC chip by heat when the IC chip containing a circuit for driving piezoelectric elements is installed to the ink-jet head for discharging an ink by driving the piezoelectric elements.
According to a first aspect of the present invention, there is provided an ink-jet head comprising:
a main head body including ink chambers formed therein;
piezoelectric elements for changing a volume of each of the ink chambers in accordance with application of a driving voltage; and
an IC chip including a driving circuit for driving the piezoelectric elements;
the IC chip being attached to an outer wall surface of the main head body via a resin material intervened therebetween.
According to a second aspect of the present invention, there is provided an ink-jet recording apparatus comprising:
an ink-jet head including:
a main head body including ink chambers formed therein;
piezoelectric elements for changing a volume of each of the ink chambers in accordance with application of a driving voltage; and
an IC chip including a driving circuit for driving the piezoelectric elements, the IC chip being attached to an outer wall surface of the main head body via a resin material intervened therebetween; and
a carriage for carrying the ink-jet head and an ink cartridge, the carriage being relatively movable with respect to an objective print medium.
According to the ink-jet head concerning the first aspect and the ink-jet recording apparatus concerning the second aspect, the IC chip is attached to the outer wall surface of the main head body via the resin material intervened therebetween. Accordingly, the heat, which is generated in the IC chip, can be transferred to the ink-jet head (main head body) through the resin material such as a potting material. The ink-jet head includes portions containing the ink, such as the ink chambers and an ink manifold. Therefore, the heat transferred to the ink-jet head is transferred to the ink contained in the foregoing portions, and the ink is jetted from the nozzles. As a result, the heat generated in the IC chip is radiated to the outside of the ink-jet head. Therefore, it is possible to provide the ink-jet head and the ink-jet recording apparatus which are excellent in heat radiation efficiency as compared with the conventional ink-jet head based on natural heat radiation for the IC chip.
The ink-jet head of the present invention and the inkjet recording apparatus including the ink-jet head may be arranged as follows. Namely, head electrodes connected to the piezoelectric elements are formed on one outer wall surface of the main head body, and chip electrodes electrically connected to the driving circuit are formed on one surface of the IC chip. The IC chip is attached to the outer wall surface of the main head body so that the one outer wall surface of the main head body is opposed to the one surface of the IC chip, and the head electrodes are electrically connected to the chip electrodes. The resin is charged between the one outer wall surface of the main head body and the one surface of the IC chip. According to the foregoing arrangement of the ink-jet head, the heat generated in the IC chip can be efficiently radiated through the resin charged between the opposing surfaces of the main head body and the IC chip. Further, the heat generated in the IC chip can be radiated through the chip electrodes and the head electrodes.
The head electrodes and the chip electrodes may be electrically connected to one another by the aid of a conductive adhesive or solder. By electrically connecting them with the conductive adhesive or solder, the IC chip can be fixedly secured to the outer wall surface of the main head body by the conductive adhesive or the solder. Moreover, the heat generated from the IC chip can be radiated through the conductive adhesive or the solder.
In the ink-jet head and the ink-jet recording apparatus according to the present invention, the IC chip may be attached to a cover plate or a piezoelectric ceramic plate for constructing the main head body via the resin material intervened therebetween. The resin may be an epoxy resin.
It is preferable that the IC chip is attached to the outer wall surface of. the main head body via the resin material intervened therebetween, and the IC chip is covered with the resin material. Because the same material is used for the resin material charged between the main head body and the IC chip and for the resin material for covering the IC chip, it is possible to simultaneously perform the step of charging the resin material between the main head body and the IC chip, and the step of covering the IC chip. Thus, it is possible to improve the efficiency of production.
According to a third aspect of the present invention, there is prov
Brother Kogyo Kabushiki Kaisha
Dickens C.
Fuller Benjamin R.
Oliff & Berridg,e PLC
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