Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-11-26
2004-11-23
Hsieh, Shih-Wen (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06820973
ABSTRACT:
This application claims priority from Japanese Patent Application No. 2002-000168 filed Jan. 4, 2002, which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid supply apparatus that can supply a liquid to a container and a printing apparatus using this liquid supply apparatus.
2. Description of the Related Art
For conventional ink-jet printing apparatuses, many means for supplying ink to an ink-jet print head have been proposed and put to practical use. Serial scan ink-jet printing apparatuses employ various ink supplying means. The serial scan ink-jet printing apparatus has an ink-jet print head from which ink can be ejected and which is mounted on a carriage movable in a main scanning direction. In this case, an image is printed on a printing medium by performing an operation of ejecting ink from the print head on the basis of image data while moving the carriage in a main scanning direction together with the print head.
In these serial scan ink-jet printing apparatuses, the most classical supplying means is tube that is extended from ink tank in a printing apparatus main body to supply ink to the print head on the carriage. However, such tube supply means may cause ink to be unstably ejected because movement of the carriage affects the flow of ink through the tube in the direction in which the carriage moves. Thus, for printing apparatuses operating at increased printing speed, the behavior of ink through the tube must be controlled. Further, the tube must have a length corresponding to reciprocation of the carriage, so that the conventional supply means has various disadvantages. For example, to avoid problems resulting from the entry of air into the tube associated with the long-time storage of the printing apparatus, a large amount of ink may be allowed to flow through the tube from ink supply source such as ink tank during the initial period of use of the printing apparatus. In this case, the ink is wastefully consumed. Further, the tube simply form path through which ink is delivered from the ink tank to the ink-jet print head. Accordingly, in spite of that little added value, the tube has the various disadvantages of increasing the size of the printing apparatus and costs, complicating the structure, and the like.
In recent years, a so-called head tank on carriage method has been employed as an ink-jet printing apparatus that does not use the tube. With the head tank on carriage method, an ink-jet print head and ink tank are integrally or separable joined together, thus constituting a head cartridge (also referred to as an “ink-jet print head unit”)
3
mounted on a carriage
4
. The printing apparatus in
FIG. 1
alternately repeats an operation of causing ink to be ejected from the print head on the basis of image data while moving the carriage
4
with the head cartridge
3
in the main scanning direction, shown by arrow A, and a transporting operation of transporting a printing medium
2
in a sub-scanning direction shown by arrow B and which crosses the main scanning direction. By alternate repeating these operations, an image is printed on the printing medium. Reference numeral
1
denotes a guide shaft on which the carriage
4
is guided so as to be movable in the main scanning direction. Reference numeral
8
denotes a cap that can cap ink ejection openings of the print head. The print head can execute a recovery process of maintaining a good ink ejection state by (preliminarily) ejecting ink that does not contribute to printing of images, to the interior of the cap
8
. Further, a suction recovery process for maintaining a good ink ejection state can be executed by introducing negative pressure into the cap
8
, which caps the ink ejection openings of the print head, and forcibly sucking and discharging ink through the ink ejection openings of the print head.
The print head may comprise, for example, an electrothermal converter to eject ink droplet through the ink ejection opening. That is, the electrothermal converter generates heat to subject ink to film boiling, so that the resulting bubbling energy can be utilized to eject ink droplet through the ink ejection opening.
With this ink supply operation based on the head tank on carriage method, ink supply path is formed between the print head and ink tank constituting the head cartridge
3
. Accordingly, the configuration of the ink supply path is very simple. Further, the ink supply path is integrally contained in the print head or the ink tank, thus enabling the size of the apparatus and costs to be reduced. Furthermore, the ink supply path can be designed to be short and has a very small number of portions in which the direction in which they extend coincides with the movement direction of the carriage
4
. This substantially prevents unstable ejection of ink attributed to the behavior of the ink during high-speed printing.
However, with the head tank on carriage method, a large amount of ink mounted in the carriage
3
results in an inevitable increase in the volume of the ink tank, constituting the head cartridge
3
. This increases the weight of the entire carriage
4
, on which the head cartridge
3
is mounted, increases the size of a motor acting as a drive source for the carriage
4
, and increases a required drive current and the size and weight of the entire ink-jet printing apparatus.
On the other hand, for small-sized ink-jet printing apparatuses, since the size of the carriage is desired to be reduced, the capacity of the ink tank that can be mounted on the carriage is limited to an extremely small value. Thus, a user is forced to frequently replace the ink tank on the carriage with new one. Further, the frequent replacement of the ink tank is out of step with the current trend to strive to protect the environment.
A so-called pit-in method is means for solving these problems.
With the pit-in method, an ink-jet print head
11
and a sub-tank
6
are mounted on the carriage
4
guided on the guide shaft
1
as shown in FIG.
2
. When ink supplied to the print head
11
from the sub-tank is consumed to reduce the amount of ink in the sub-tank
6
below a predetermined value, the carriage
4
moves to a predetermined home position as shown in FIG.
2
. At the home position, ink from a main tank
7
is filled into the sub-tank
6
, and then a printing operation is resumed. In the example in
FIG. 2
, a connecting member
18
on the side of the main tank
7
is connected to a hollow needle
14
on the side of the sub-tank
6
to fill ink from the main tank
7
into the sub-tank
6
. The main tank
7
is provided with a bag
15
in which ink is accommodated. An ink supply path
16
composed of a channel constituting member including a flexible tube
17
is formed between the bag
15
and the connecting member
18
. When ink is filled, a moving member
13
moves leftward in the figure along the direction of arrow “a” to join its arms
13
A to the connecting member
18
. Subsequently, the moving member
13
moves upward in the figure along the direction of arrow “b” to join the connecting member
18
to the hollow needle
14
on the side of the sub-tank
6
.
The pit-in method serves to reduce the weight of the entire carriage
3
, on which the print head
11
and the small-capacity sub-tank
6
are mounted, and to enable high-speed printing based on high-speed scanning. Further, since ink from the main tank
7
is filled into the sub-tank
6
at the home position, the number of printing medium
2
to be actually printed is not limited. Furthermore, no tube is required compared to the tube supply method, described previously, thus simplifying the configuration of the entire apparatus.
To complete the technique for the pit-in method, the most important technical point is to reliably fill the sub-tank
6
with ink. That is, for a pit-in period when the carriage
3
is moved to the home position to supply the sub-tank
6
with ink, the most important technique is how to supply ink from the main tank
7
to the sub-tank
6
.
Fitzpatrick ,Cella, Harper & Scinto
Hsieh Shih-Wen
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