Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-04-14
2002-11-05
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06474780
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head and a head cartridge used for a printer, a video printer, or the like, which serves as an output terminal of a copying machine, a facsimile equipment, a wordprocessor, a host computer, or the like. The invention also relates to a liquid discharge apparatus provided with such liquid discharge head, and a method for manufacturing liquid discharge heads. More particularly, the invention relates to a liquid discharge head which discharges ink or some other liquid for use of recording as flying droplets from its discharge ports (orifices) to record by allowing such liquid to adhere to a recording medium. The invention also relates to a head cartridge and a liquid discharge recording apparatus provided with such head, as well as a method for manufacturing liquid discharge heads.
2. Related Background Art
Conventionally, an ink jet recording apparatus, which performs recording, as a liquid discharge recording apparatus, by discharging ink from the orifices of the liquid discharge head, is known as an excellent recording apparatus in that it has lower noises, and higher recording speeds, among some other advantages. As to the ink jet recording methods for such ink jet recording apparatuses, there have been proposed many methods, and some of them have been implemented as products and already put on the market after some improvements, while some of them are still under study at present for the implementation of its practical use.
As an example of the liquid discharge head used for the ink jet recording apparatus, there is one which is schematically shown in FIG.
1
and FIG.
2
.
FIG. 1
is a cross-sectional view which shows a part of the liquid discharge head manufactured by the conventional art.
FIG. 2
is an exploded perspective view which schematically shows the liquid discharge head represented in FIG.
1
.
As shown in FIG.
1
and
FIG. 2
, the conventional liquid discharge head comprises an orifice plate
440
having a plurality of discharge ports (orifices)
441
for discharging ink; a ceiling plate
400
for the formation of plural liquid flow paths
401
communicated with each of the discharge ports
441
; and an elemental substrate
100
having a plurality of electrothermal transducing devices (heaters)
101
on it for the generation of thermal energy to discharge ink from the discharge ports
441
. Therefore, the head is formed by the ceiling plate
400
, and the head substrate
200
which is provided with the plural electrothermal converting elements
101
and liquid flow paths
401
. Then, the orifice plate
400
is directly bonded to the head substrate
200
by use of bonding agent.
On the orifice plate
440
, fine discharge ports
441
are formed for ink discharges as described above. Each of the discharge ports
441
is an important constituent of a liquid discharge head upon which its performance depends greatly. Then, in order to stabilize the directions in which ink droplets are discharged from each of the discharge ports
441
, it is known that the circumference of each discharge port
441
of the orifice plate
440
should desirably be provided with the liquid repellency (hereinafter referred to as ink repellency or an ink repellent layer to make the description simpler) at least on its outer surface side. Therefore, it has been practiced to form the ink repellent layer on the surface of the orifice plate for the provision of the ink repellency on the circumference of each discharge port.
However, the outer surface
440
a
of the orifice plate where the ink repellent layer is formed is rubbed by the cleaning blade for wiping, which is needed for the maintenance of ink discharge condition by the execution of the recovery process thereof. As a result, there may be a case where the ink repellent layer is scraped by the cleaning blade and worn out or damaged depending on the material of the ink repellent layer, the formation method thereof, the material of the blade, or the like. Then, it is becomes difficult to maintain the ink repellency of the kind in good condition for a long time in some cases.
Therefore, attention has been given to this worn-out problem of the ink repellent layer, and for example, it has been proposed to disperse the ink repellent material in the material with which to form the orifice plate as disclosed in the specification of Japanese Patent Application Laid-Open No. 57-157765.
Nevertheless, when the material having ink repellency in it is used as the material of the orifice plate, there is encountered a new problem that in general, the higher the ink repellency contained in a material, the lower becomes the bonding power between the orifice plate and the head substrate. As a result, it has not been implemented as yet to provide a highly reliable liquid discharge head which is capable of maintaining the ink repellency of the orifice plate in good condition, while presenting the firm bonding between the orifice plate and the head substrate. This problem has been dealt with only by the improvement attempted to provide the ink repellent layer more effectively so far.
Under the circumstances, the inventors hereof have studies and acquired the knowledge that with the surface treatment given to the orifice plate at least on its bonding surface side, it becomes possible to bond the orifice plate with the head substrate in good condition even when adopting the fluororesin having an excellent ink repellency or the resin having the ink repellent material dispersed in it as the orifice plate material.
SUMMARY OF THE INVENTION
The present invention is designed with such new knowledge that the inventors hereof have acquired. It is an object of the invention to provide a liquid discharge head for which the bonding force is secured firmly between the head substrate, and the orifice plate having ink repellency on it to be made capable of maintaining a good ink repellency for a long time, and to provide a head cartridge using such head as well. It is also the object of the invention to provide a liquid discharge apparatus using such head, and a method for manufacturing ink jet heads.
In this respect, the orifice plate is a thin film sheet of approximately several tens of pm in some cases, depending on the modes to be adopted. Then, when resin or the like is used as the material of the orifice plate, the strength of the orifice plate becomes weaker to make its handling difficult. Also, the orifice plate is subjected to expansion or deformation due to heat if a high temperature treatment is given when the orifice plate is bonded to a head substrate. Particularly, since the thermal expansion coefficient is different depending on the material to be used, this phenomenon tends to exert influence on the bonding of the orifice plate and head substrate.
It is another object of the invention to provide a liquid discharge head whose orifice plate is capable of maintaining a good ink repellency for a long time even when a thin resin material having ink repellency or the like is used for the orifice plate which is bonded to the head substrate at a high temperature, and also, it is made possible to prevent the orifice plate from being expanded or deformed by the application of heat so as to bond the orifice plate assuredly to the head substrate. It is still another object of the invention to provide a head cartridge, a liquid discharge recording apparatus provided with such head, and a method for manufacturing liquid discharge heads as well.
In order to achieve the objects described above, an ink jet head of the present invention comprises a head substrate provided with a plurality of ink paths, and at the same time, each of the pressure generating devices being arranged for each of the paths; and an orifice plate provided with ink discharge openings each communicated with each of the ink paths. Then, the bonding surface side of the orifice plate to the substrate is provided at least with the surface treatment.
The orifice plate is resin containing fluorine.
The
Hiroki Tomoyuki
Iketani Masaru
Kashino Toshio
Kubota Masahiko
Ono Takayuki
Barlow John
Brooke Michael S
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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