Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-06-06
2001-04-10
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S048000
Reexamination Certificate
active
06213592
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liquid discharging method typified by an ink jet recording method of discharging liquid droplets, a liquid discharging head typified by an ink jet recording head, a liquid discharging head cartridge and an ink jet recording apparatus.
2. Related Background Art
An ink jet recording method of discharging minutes ink droplets from a nozzle (discharge port) to thereby effect the recording of characters, figures, etc. has been attracting attention as a recording method in an apparatus for effecting recording, such as a printer, a copying apparatus, a facsimile apparatus or a plotter. The ink jet recording method has the excellent advantage that the outputting of highly minute images and high-speed printing are possible. Particularly, a method of producing air bubbles in liquid by an electro-thermal converting member (hereinafter also referred to as the heater) and using this produced bubble pressure, i.e., the so-called bubble jet method, is characterized in that the downsizing of the apparatus and the higher density of image are easy to realize.
Now, the liquid discharged from the nozzle by the bubble pressure is not limited to ink liquid, but it is possible to discharge other liquids. So, herein, a method of discharging not only ink, but generally liquids is called the liquid discharging method, and in the liquid discharging method, a method of discharging ink liquid to a recording medium to thereby effect recording is called the ink jet recording method.
In the field of ink jet recording, the requirement for the coloring of recording is high. As the construction of an ink jet recording apparatus which satisfies the requirement for the coloring, there is adopted, for example, one in which color recording is effected with ink jet recording heads of various colors are arranged in parallel along the scanning direction on a carriage, or one in which color ink jet recording heads comprising ink tanks containing therein yellow, magenta and cyan inks used for color recording and recording heads for discharging these inks, the ink tanks and the recording heads being arranged in parallel so as to make a unit, and a single ink jet recording head for black only are disposed on a carriage and color recording is effected.
FIG. 20
of the accompanying drawings is a schematic cross-sectional view of the ink flow path portion of a recording head of the conventional bubble jet type using an electro-thermal converting member to produce air bubbles to thereby discharge ink liquid droplets. A heater portion
91
is embedded in an ink flow path
92
, one end of which communicates with a discharge port
93
, and the ink flow path
92
is filled with ink. Heat produced by the heater portion
91
acts on the ink filling the ink flow path
92
, whereby the ink on the heater portion
91
causes a sudden state change (bubbling phenomenon) and some of the ink in the ink flow path
92
is discharged and flies from the discharge port
93
to a recording medium, whereby recording is effected. The bubble produced by the heat generation of the heater portion
91
shrinks and disappears when the heating by the heater portion
91
ends, and the ink flow path
92
again becomes filled with ink (the ink refill process).
However, in the conventional recording head as shown in
FIG. 20
, the bubble produced may become larger than necessary and in such case, much time is required for the disappearance of the bubble. Also, at the same time as the energy during bubbling is transmitted from the heater portion
91
toward the discharge port
93
(in Q direction), the energy is greatly transmitted toward the upstream side (in P direction) which is the ink supply side and therefore, there is the problem to be solved that much time is required for refilling the ink flow path
92
with the ink. A pressure wave propagated to the upstream side with the production of the air bubble is herein called a back wave.
The recording head of such flow path construction as shown in
FIG. 20
could coped with the printing speed in the recording apparatus as is conventional, but in the recent recording apparatus wherein higher speed recording is desired, the ink refill time has been not enough for the printing speed and in some cases, the non-discharge of the ink has occurred.
Also, in an ordinary ink jet recording head, a common ink chamber for supplying ink to a plurality of ink flow paths is provided upstream of the flow paths, but when such a back wave is strongly transmitted to the upstream side of the ink, this back wave may be propagated to other ink flow path through the common liquid chamber and may adversely affect the discharged state of the ink in that flow path.
The above-noted facts that much refill time is required and that there is the adverse effect of the back wave have been problems to be solved that generally apply to liquid discharging heads utilizing air bubbles to discharge liquid droplets.
Various propositions have heretofore been made in order to solve such problems. Description will hereinafter be made of propositions made to an ink jet recording head, and it is apparent that the following construction is generally applicable to liquid discharging heads.
For example, as described in Japanese Laid-Open Patent Application No. 55-100169, there is known a construction in which a fluid resistance portion is provided upstream of a heater portion in an ink flow path for generating heat energy. The structure of such ink jet recording head is shown in
FIG. 21
of the accompanying drawings. As shown in
FIG. 21
, ink
904
flows from an inlet opening
903
at one end of an ink flow path
902
into the ink flow path
902
communicating with a discharge port
901
for discharging the ink. Near the discharge port
901
at the other end of the ink flow path
902
, a heater
905
for generating heat energy utilized to form air bubbles and discharge the ink is disposed on a wall surface, and a barrier
906
is protrudingly provided on the upstream side (the inlet opening
903
side) of the heater
905
on the wall surface on which this heater
905
is disposed. In such recording head, when an electrical signal is inputted to the heater
905
, an air bubble is produced in the ink
904
and by the action thereof, ink droplets
907
are discharged from the discharge port
901
toward a recording medium
908
. At the same time, the acting force of the air bubble acts also in the anti-discharging direction (the direction toward the inlet opening
903
), but due to the barrier
906
provided in the anti-discharging direction, the fluid resistance in the anti-discharging direction becomes greater than the fluid resistance in the discharging direction, and the acting force of the air bubble is effectively utilized for the discharging of the ink droplets
907
.
Also, as a method of preventing the loss of energy toward the upstream side of such a heater, there is disclosed in Japanese Laid-Open Patent Application No. 59-199256 a method of providing, besides discharge energy generating means directly concerned in the discharge, second energy generating means which is not directly concerned in the discharge. By using the second energy generating means, the loss of the energy generated by the discharge energy generating means toward the upstream side is prevented.
Also, in Japanese Laid-Open Patent Application No. 62-240558, there is disclosed a method of providing heating means in a liquid chamber, in addition to the heater arrangement of Japanese Laid-Open Patent Application No. 59-199256.
In Japanese Laid-Open Patent Application No. 63-102945, there is disclosed structure in which discretely from a discharge heater for controlling discharge, second energy generating means is provided so as to be orthogonal to a flow path so that the component in the direction of the flow path width of this second energy generating means may become greater than the flow path width.
Further, Japanese Laid-Open Patent Application No. 63-197652 or Japanese Laid-Open Patent Applic
Asakawa Yoshie
Kashino Toshio
Kimura Makiko
Kudo Kiyomitsu
Okazaki Takeshi
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hallacher Craig A.
LandOfFree
Method for discharging ink from a liquid jet recording head... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for discharging ink from a liquid jet recording head..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for discharging ink from a liquid jet recording head... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2546826