Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-02-25
2004-12-14
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S085000
Reexamination Certificate
active
06830322
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liquid ejection apparatus and, more particularly, it relates to a liquid ejection apparatus of the type adapted to generate negative pressure in the liquid ejection head by means of the water head difference between the liquid ejection head and the liquid bag containing liquid to be supplied to the liquid ejection head.
2. Related Background Art
Liquid ejection apparatuses (ink-jet printers) are designed to record images on a recording medium by ejecting liquid such as ink from a liquid ejection means (liquid ejection head) onto the recording medium. Such apparatuses provide a number of advantages including that the liquid ejection means can be easily down-sized, that the apparatus can record high definition images on plain paper without any particular treatment at low running cost, that they are of the no-impact type and hence emit little noise, and that they can record color images by using inks of different colors without difficulty.
The liquid ejection means (liquid ejection head) of the liquid ejection apparatus of the above-identified type is designed to eject liquid from a liquid ejection port by utilizing film boiling that is produced in the liquid such as ink by means of thermal energy generated by an electrothermal transducer or a heat-emitting element. The liquid ejection means (liquid ejection head) of the type that is adapted to eject liquid by utilizing thermal energy as described above can be manufactured by forming its components including the electrothermal transducer, the electrodes, the walls of the liquid flow path and the ceiling plate on a substrate, utilizing a semiconductor manufacturing process that typically involves techniques such as etching, evaporation and sputtering. The manufacturing process makes it possible to densely arrange liquid flow paths and liquid ejection ports without difficulty in order to provide a down-sized liquid ejection means. It is also possible to produce an oblong and/or flat (two-dimensional) liquid ejection means (liquid ejection head) by exploiting the advantages of IC technologies and micro-processing technologies. Then, a liquid ejection apparatus can be equipped with a plurality of liquid ejection means that are mounted densely in the liquid ejection apparatus.
FIG. 6
of the accompanying drawings schematically illustrates a known liquid ejection apparatus of the type under consideration. Referring to
FIG. 6
, a plurality of (four in
FIG. 6
) liquid ejection heads (liquid ejection means)
201
are mounted on a carriage
210
. The liquid ejection heads
201
are provided respectively with electrothermal transducers (not shown) for generating thermal energy, liquid flow paths through which liquid is supplied, and liquid ejection ports (not shown), and are adapted to eject liquid through the liquid ejection ports, utilizing the pressure change generated by growth and contraction of bubbles due to film boiling of liquid produced by the thermal energy that is generated by the electrothermal transducers. The carriage
210
is reciprocatingly guided by a guide shaft
211
and a guide plate
212
. It is driven to reciprocate by a carriage motor
213
by way of a timing belt mechanism
214
. An image (including characters and/or signs) is recorded on a recording medium
215
, which may typically be a sheet of recording paper, by driving the liquid ejection heads
201
according to recording information applied to them in synchronism with the reciprocating movement of the carriage
210
.
As a recording session is completed for a single line, the recording medium
215
is moved forward by a distance corresponding to the line by feed rollers (not shown) and delivery rollers
216
. Then, the next recording session starts for the next line, moving the carriage
210
relative to the recording medium
215
that is now lying still. In this way, the image recording operation proceeds until all of the intended image is recorded on the recording medium
215
, alternately repeating the intermittent forward movement of the recording medium and the recording session. In
FIG. 6
, reference symbol
202
denotes cartridges communicating with the respective liquid ejection heads
201
by way of tubes
203
and operating as supply source of liquid such as ink for the liquid ejection heads
201
. The cartridges are removably fitted to the main body of the liquid ejection apparatus. In
FIG. 6
, reference symbol
217
denotes spurs that cooperate with the delivery rollers
216
to forwardly move the recording medium
215
.
Liquid ejection recovery system
220
is provided at a position located within the limits of movement of the liquid ejection heads
201
but outside the recording area of the heads, in order to avoid defective liquid ejection (including non-ejection) and maintain the normal function of liquid ejection of the liquid ejection heads
201
. The liquid ejection recovery system
220
comprises caps
221
for hermetically sealing (capping) the corresponding liquid ejection ports of the liquid ejection heads
201
and a suction pump (not shown in FIG.
6
), which is connected to the inside of the caps
221
. The suction pump is driven to operate while the liquid ejection heads
201
are capped so as to apply negative pressure to the liquid ejection ports and draw out of the ejection ports foreign objects, such as thickened liquid, air bubbles and dust, with liquid. The foreign objects that are thus drawn out are then driven out through tubes
222
.
As pointed out above, a liquid flow path of the known liquid ejection apparatus comprises liquid ejection heads, liquid cartridges and a liquid ejection recovery system that are typically arranged in a manner as shown in FIG.
2
. Referring now to
FIG. 2
, the liquid cartridge
102
(which corresponds to liquid cartridge
202
in
FIG. 6
) comprises a liquid bag
103
, a housing
104
containing the liquid bag
103
, a rubber peg
105
forming a supply port for leading liquid out of the liquid bag
103
, a rubber peg holder
106
and a detector plate
107
for detecting the amount of the remaining liquid. The rubber peg holder
106
is made of resin and adapted to hold the rubber peg
105
. It has an end whose outer periphery is held in tight contact with the inner surface of the liquid bag
103
. The rubber peg holder
106
has a flange
108
that is rigidly fitted to the housing
104
. The liquid bag
103
has two oppositely disposed sides whose areas are the largest among all the sides of the bag. One of these two sides, which faces downward, is securely fitted to a side of the housing
104
by means of an adhesive or bonding agent, while the other side, which faces upward, holds the detector plate
107
, which is rigidly fitted to a part of that side of the bag.
The apparatus main body comprises a cartridge-containing section
109
for containing a liquid cartridge
102
. A hollow needle
110
is arranged at the cartridge-containing section
109
and communicates with the liquid ejection head
101
by way of a supply tube
111
so that, as the liquid cartridge
102
is put into the cartridge-containing section
109
, the hollow needle
110
is driven to go through the rubber peg
105
of the liquid bag
103
. Then, liquid can be supplied from the liquid bag
103
to the liquid ejection head
101
.
In the instance of
FIG. 6
, four liquid cartridges
202
are provided for the four liquid ejection heads
201
. When recording color images, typically cyan, magenta, yellow and black inks are contained respectively in the four liquid cartridges
202
for the four liquid ejection heads
201
so that the liquid ejection heads
201
can record images using these color inks. As seen from
FIG. 2
, a plastic liquid bag
103
is put in each of the liquid cartridges (
202
in
FIG. 6 and 102
in
FIG. 2
) and ink is supplied from the liquid bag
103
to the corresponding liquid ejection head
101
by way of the supply tube
111
.
As liquid is supplied from the liquid bag
103
in the liquid cartridge
102
and ejecte
Kanome Osamu
Shihoh Makoto
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