Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-04-11
2002-07-02
Hallacher, Craig A. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S087000
Reexamination Certificate
active
06412931
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to an ink jet recording apparatus, an ink jet head cartridge mountable thereto and an ink container mountable thereto.
In a type of ink jet recording apparatus wherein ink is deposited on the recording material to effect the recording, an ink cartridge containing a predetermined quantity of the ink is exchangeable to replenish the ink jet recording apparatus with the ink. When the cost of the ink jet recording head is low, a head-container cartridge is used wherein the recording head and the ink container having a capacity of a predetermined quantity of the ink are constructed as a unit. In the latter type, the recording head is exchanged with fresh one each time after a predetermined amount of recording is effected. Therefore, the good recording quality can be maintained. Even if trouble leading to degraded recording quality occurred, the inoperable time period could be reduced, because the ink jet recording head which is the key element could be easily exchanged. In addition, the liability of introduction of foreign matter attributable to the replenishment of the ink can be avoided.
In such a head-container cartridge, the ink container containing the ink to be supplied to the ink ejector is provided, which is required to satisfy the following:
(1) The ink does not leak out;
(2) The ink does not evaporate;
(3) It contains a predetermined quantity of the ink and supplies it to the ejector; and
(4) It does not obstruct the ink ejection by the ejector.
In order to practically satisfy the above functional requirements, an ink container of an ink bag type or a sponge type are known. In the latter type, an ink absorbing material is disposed in the ink container, so that the ink in the ejector is under the vacuum.
The ink bag type involves the problem regarding the above requirement (4). More particularly, in order to avoid the influence by the static head of the ink to the ejector, the relative positional relation between the recording head and the ink container is more or less limited. In addition, the ink bag should be protected by an outside casing for the purpose of easy handling, which results in the cost increase.
The sponge type is free from the influence to the ejection by the static head of the ink.
Referring first to
FIG. 1
, there is shown a perspective view of an ink jet head cartridge of this type. The cartridge includes an ink container
160
, an ink jet recording head mounted to the ink container
160
, porous material
162
in the ink containing portion
160
a.
The porous material
162
is filled with the ink. The ink is supplied to the ink jet recording head
164
by way of an integrating passage not shown.
Ejection outlets
163
of the ink jet recording head
164
receive image signals from the main assembly of the apparatus to eject the ink droplet onto a recording material. A connector
165
establishes electric connection between the main assembly and the recording head.
A small chamber
160
c
is formed at a part of the container
160
. It communicates with the ink containing portion
160
a
in the container through a connecting groove
160
b.
An air venting hole
160
d
is formed in a part of the small chamber. Following the ink ejection for the image recording, the air is introduced through the air venting hole
160
d.
A cover
161
seals the ink containing portion
160
a
and the small chamber
160
c.
The ink jet cartridge described above is normally positioned in use with the recording head
164
at the bottom, and therefore, the air venting hole
160
d
at the top. Accordingly, the ink does not leak out of the cartridge.
The air venting hole is provided to compensate the pressure change due to the consumption of the ink in the ink container or due to the temperature change of the air in the ink container, by communication between the inside and outside of the container. However, in the conventional ink container, the ink is easily evaporated through the air venting hole (requirement (2)). The ink evaporates with time with the result of following problems.
For example, water-based ink which is widely used from the standpoint of safety, is generally constituted by water, dye and non-volatile solvent. With the evaporation, and therefore, reduction of the volatile contents such as water, decomposition of the ink significantly changes to such an extent that the recording property such as the fixing property and the image density is influenced and that the ejectors are clogged by the increase of the ink viscosity. In addition, usable quantity of the ink decreases so that it is not economical. It will be understood that the problems arising from the evaporation are significant particularly in the case of the ink container having a smaller capacity.
When the cartridge of the above-described example is left with the air venting hole at the bottom as shown in
FIG. 2
, or it is left in its horizontal position, the ink in the container gradually lowers due to the ambient temperature change or the like. Then, an ink layer is formed in the porous material
162
at the bottom at the side where the air venting communication groove is formed, and on the other hand, an air layer is formed at the top where the communication passage with the recording head is formed. If the temperature rises with this state, the inside pressure increases by the expansion of the air remaining in the container, so that the ink A is pushed to the outside through the communication groove
160
b
and through the air venting hole
160
d,
and therefore, the ink leaks out.
In addition, when an impact is applied to the ink container which is positioned with its air venting hole at the bottom, the ink droplets come out through the communication groove
160
b,
and the ink leaks out of the container through the air venting hole
160
d.
When the ink jet cartridge described above is used with the ink ejection outlets
163
at the bottom as shown in
FIG. 3
, the ink remains in the region I which is indicated by the hatched lines and which is remote from the ink jet head
164
without being consumed.
It would be considered to incline the bottom
162
b
of the ink container, in an attempt to prevent the ink from remaining. However, in order to accomplish this without reduction of the ink capacity, the ink jet recording head
164
has to be shifted downwardly toward the recording material. Then, the height of the entire apparatus
100
is increased, or the ink retaining performance decreases by the increase of the height of the ink absorbing material
162
. Then, the ink more easily leaks out through the ink ejection outlets
163
.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide an ink container, an ink jet recording head cartridge with the ink container as a unit and an ink jet recording apparatus using the same, wherein the evaporation of the ink can be suppressed for a long period of time, by which the good recording property can be stably maintained.
It is another object of the present invention to provide an ink container, an ink jet recording head with the ink container as a unit and an ink jet recording apparatus using the same wherein the leakage of the ink is effectively prevented.
It is a further object of the present invention to provide an ink container, an ink jet recording head cartridge with the ink container and an ink jet recording apparatus using the same, wherein the ink in the container is effectively supplied to the ink inlet of the recording head substantially without the ink remained in the container.
According to an aspect of the present invention, there is provided an ink jet head cartridge, comprising: a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an air venting opening for communication between said container and ambience to allow supply of the ink from said container to said recording head; wherein said air venting opening is constituted by an outside opening and an inside opening and a
Ebata Tokihide
Hirabayashi Hiromitsu
Koitabashi Noribumi
Kurata Mitsuru
Sugimoto Hitoshi
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