JP3739840B2 - ink cartridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink cartridge used by being mounted on a detachable printer or the like, and more particularly to a technique for preventing ink leakage during transportation and storage.
[0002]
[Prior art]
Conventionally, in an image forming apparatus such as a printer, a method of supplying ink to a print head using an ink cartridge has been used. In this method, an ink cartridge in which ink is contained in a case is mounted at a predetermined position of the printer and connected to the print head, whereby ink is supplied from the ink cartridge to the print head as needed. However, in this ink supply method using the ink cartridge, as the ink is supplied, the ink level in the cartridge, i.e., the case, is lowered and a negative pressure is generated in the case. There is a drawback in that it is obstructed and blurring occurs in printing. Therefore, in order to eliminate such a drawback, a cartridge, that is, a case in which a vent hole is provided in a case is used. However, in such a cartridge, although the vent hole is provided at a position where the cartridge is mounted on the printer and not immersed in the ink in the cartridge (case), the cartridge is mounted on the printer when the cartridge is transported or stored. When tilted or tilted to a state different from the state, there is a risk that the air hole is immersed in the ink and the ink leaks from the air hole. For this reason, conventionally, a filter that allows air to pass through the cartridge (case) but does not allow liquid to pass (leak) has been attached.
[0003]
[Problems to be solved by the invention]
However, even when a cartridge having a filter attached to the vent hole is used, if the cartridge is left in a state where the ink and the filter are in contact with each other and the temperature rises rapidly, the ink may leak. This is because positive pressure is applied to the liquid level of the ink in the cartridge (case) due to thermal expansion of air in the space in the cartridge (case) or evaporation of the ink, and the ink is pressed against the filter. That is, as described above, the filter can prevent the passage (leakage) of liquid at normal pressure, but the liquid can pass (leakage) when the liquid is pressed against the pressure at a certain pressure. It is. Although it is possible to prevent leakage of the liquid by reducing the pore diameter of the filter, in this case, there is a possibility that it is impossible to secure the air flow necessary for normal outflow of ink.
[0004]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink cartridge having a vent hole and capable of preventing ink leakage during transportation and storage. Is.
[0005]
[Means for Solving the Problems]
In the ink cartridge according to the present invention, ink is accommodated in a case in which air holes are formed at two or more locations, and air is allowed to pass through each of the two or more air holes. A filter that does not pass is attached, and the case inner side surface of the filter that is attached to at least one of the two or more vent holes is buried in the ink, regardless of the position of the case. It is something that is supposed to not.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the ink cartridge of the present invention, the ink is accommodated in a case in which air holes are formed at two or more locations, and air is allowed to pass through each of the two or more air holes. A filter that does not pass is attached, and the case inner side surface of the filter that is attached to at least one of the two or more vent holes is buried in the ink, regardless of the position of the case. Therefore, even if a positive pressure is generated in the space inside the case due to temperature rise, this positive pressure is quickly eliminated by a filter whose inner side surface is not buried in ink, and immediately The space inside the case returns to the same pressure as the outside of the cartridge. Therefore, even if a positive pressure is generated in the space inside the case, the ink is not pressed against any of the filters attached to the two or more vent holes, and ink leakage can be prevented. .
[0007]
In the present invention, the filter is not particularly limited as long as the filter allows air to pass but does not allow ink to pass at normal pressure. It is preferable to use a porous film made of a fluororesin such as ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer. This is because the porous film made of fluororesin does not deteriorate in air permeability and ink resistance over a long period of time, and can prevent ink leakage for a long period of time, and is low in price, thereby reducing the product cost. This is because it can be reduced. The average pore diameter of the porous membrane made of a fluororesin is generally 0.05 to 10 μm, preferably 0.1 to 4 μm. When the average pore diameter is smaller than 0.05 μm, the air permeability tends to be reduced, and it becomes difficult to quickly eliminate the positive pressure generated in the space inside the case. When the average pore diameter is larger than 10 μm, the membrane The strength tends to decrease, and stability due to long-term use tends to be difficult to obtain. The porosity is generally 30 to 90%, preferably 60 to 85%. When the porosity is smaller than 30%, the air permeability is lowered, and it tends to be difficult to quickly eliminate the positive pressure generated in the space inside the case. When the porosity is larger than 90%, The film strength tends to decrease, and stability due to long-term use tends to be difficult to obtain.
[0008]
【Example】
FIG. 1 is a cross-sectional view showing the configuration of an ink cartridge according to an embodiment of the present invention. In the figure, ink 2 is contained in a case 1. An ink injection hole 31 is formed in a predetermined portion of the upper plate of the case 1. After the ink 2 is injected into the case 1 from here, the ink injection hole 31 is sealed with a cap 32. A vent hole 34 is formed in the cap 32, and a filter 33 made of a polytetrafluoroethylene porous membrane is attached to the vent hole 34. A vent hole 42 is formed in a predetermined portion of the lower plate of the case 1, and a filter 41 made of a polytetrafluorothiethylene porous film is attached to the vent hole 42. Here, the vent holes 34 and the vent holes 42 are formed at the same time in the ink 2 regardless of the position of the cartridge (case 1) on the inner side surface of the case 1 of the filters 33 and 41 attached to the vent holes 34 and 41, respectively. The position is not buried. As a matter of course, the amount of ink 2 accommodated is adjusted to an amount necessary to obtain such a positional relationship. The cartridge (case 1) is provided with an ink supply port (not shown) connected to the print head in a state where the cartridge is mounted at a predetermined position of the printer. Further, the ink injection hole 31 or the vent holes 34 and 42 may be used as the ink supply port without providing a special ink supply port in the cartridge (case 1). In this case, when the cartridge (case 1) is mounted at a predetermined position of the printer, the cap 32 is removed and the ink injection hole 31 is connected to the print head. Alternatively, in a state where the cartridge (case 1) is mounted at a predetermined position of the printer, the filter 33 (41) in the air hole 34 or the air hole 42 is removed, and the air hole 34 or the air hole 42 is connected to the print head. The
[0009]
Hereinafter, the present invention will be described in more detail with reference to experimental examples.
[0010]
Sample 1
The ink cartridge shown in FIG. 2 was created. In FIG. 2, a cylindrical plastic container 11 having a diameter of 2 cm and a height of 12 cm is filled with 4 cm ^{3 of} commercially available water-based ink (surface tension 33 dyne / cm) 12, and both ends of the container 11 are made of plastic. Caps 21 and 23 are attached. At the center of each of the caps 21 and 23, vent holes 22 and 24 having a diameter of 5 mm are formed, and filters 33 and 41 are thermally welded to the inner side surfaces thereof. Here, the filters 33 and 41 are polytetrafluoroethylene porous membranes (manufactured by Nitto Denko Corporation) having a thickness of 240 μm, an average pore diameter of 0.6 μm, and a porosity of 71%.
[0011]
Sample 2
The ink cartridge shown in FIG. 3 was produced. 3, the same reference numerals as those in FIG. 2 denote the same or corresponding parts. This ink cartridge is different from that shown in FIG. 2 in that the air holes 22 are not formed in the cap 21 and the filter 33 is not attached.
[0012]
Prepare 5 ink cartridges of Samples 1 and 2 above, put them in a cold cycle tester, and keep 5 cycles in an atmosphere of −30 ° C. for 5 hours and then immediately in an atmosphere of 70 ° C. for 5 hours. The cycle was repeated. After 5 cycles, the filter 41 in contact with the ink was observed. As a result of the observation, no ink leakage was observed in the filter 41 in any of the five ink cartridges of the sample 1, and no ink leakage was observed in the filter 41 in any of the five ink cartridges of the sample 2.
[0013]
From the above experimental results, the effectiveness of the present invention was confirmed.
[0014]
In the above-described examples and experimental examples, the description has been given of the cartridge in which the ventilation holes are provided in two places of the case and the filter is attached to each ventilation hole. However, the present invention is not limited to this, and Needless to say, the same effect can be obtained even if three or more locations are provided with vent holes and a filter is attached to each vent hole.
[0015]
【The invention's effect】
As described above, according to the ink cartridge of the present invention, ink is accommodated in a case in which air holes are formed at two or more locations, and air passes through each of the two or more air holes. However, a filter that does not allow ink to pass through is attached at normal pressure, and the filter attached to at least one of the two or more ventilation holes, regardless of the posture of the case. Since the case inner side surface is not buried in the ink, the inner space of the cartridge is attached to one of the two or more ventilation holes regardless of the posture of the cartridge. As a result, even if the cartridge is exposed to a rapid temperature rise, the pressure inside the cartridge will increase. Flip not, it is possible to prevent ink leakage.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an ink cartridge according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a configuration of an ink cartridge used in an experimental example of the present invention.
FIG. 3 is a cross-sectional view showing a configuration of an ink cartridge used in an experimental example of the present invention.
[Explanation of symbols]
1 Case 2 Ink 31 Ink injection hole 32 Cap 33 Filter 34 Vent hole 41 Filter 42 Vent hole

Claims (3)

Ink is accommodated in a case in which air holes are formed at two or more locations, and a filter that allows air to pass through each of the two or more air holes but does not pass the ink at normal pressure is attached. An ink cartridge in which an inner side surface of the case of the filter attached to at least one of the two or more ventilation holes is not buried in the ink regardless of the posture of the case. . The ink cartridge according to claim 1, wherein the filter is a porous film made of a fluororesin. The ink cartridge according to claim 2, wherein the fluororesin is polytetrafluoroethylene.

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