JP2003103795A - Ink storage/outflow structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress as much as possible problems such as evaporation and a reverse flow of ink by communication with the atmosphere in an ink tank, and an ink discharge failure by a negative pressure rise in the tank. SOLUTION: A sliding part which makes the inside of the ink tank a negative pressure is formed of a high-viscosity fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for accommodating and discharging ink that is accommodated in a free state of a printing apparatus that uses liquid ink such as an ink jet printer.

[0002]

2. Description of the Related Art In an ink tank such as an ink jet printer, the ink may leak or blow out unless the pressure inside the ink tank is kept low with respect to the atmospheric pressure. Although the ink may leak due to the expansion of the volume, Japanese Patent No. 3185494 discloses an ink tank in which a movable piston for covering the rear end of the ink is arranged.

[0003]

However, in the case of providing the piston for making the inside of the ink tank a negative pressure by its own weight, there is a gap between the ink tank and the piston in order to make the piston slidable. Since it is formed and is in contact with the atmosphere, the ink gradually evaporates, and there is a problem that it can not be used because it will be exhausted if left unused for a long time, or it will dry even if the ink is not exhausted As a result, the viscosity of the ink increases, and there is a problem in that the ink does not flow out from the recording head, resulting in ejection failure. Further, when gas is present in the ink, if the volume expansion of the gas occurs, the ink will leak from the gap between the piston and the ink tank. In order to solve this problem, if the piston is formed with a rubber elastic body and the gap in the ink tank is eliminated, this time the sliding of the piston that works with ink ejection is impaired and the negative pressure in the ink tank rises further, There was a problem that it resulted in defective ink ejection.

[0004]

That is, according to the present invention, an ink outlet is provided in an upper portion of an ink storage chamber that stores ink in a free state and opens downward, in order to cause the ink to flow out by the suction force of the ink suction means. An ink storage / outflow structure is provided in which an ink storage chamber is sealed by arranging a fluid stopper that moves along with the interface movement due to the volume reduction of the ink stored in contact with the ink below the ink. Use as a summary.

[0005]

[Function] Since the liquid stopper is a liquid having a higher viscosity than ink and contacts the inner wall of the ink storage chamber and has wall resistance, the ink is kept in the ink tank and is not in communication with the atmosphere. In addition to suppressing the evaporation and backflow of the ink, even when the ink flows out during printing, it moves according to the degree of the outflow of ink.
Stable ink ejection can be obtained without excessive negative pressure.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example will be described below with reference to the drawings. 1 is an ink cartridge for a so-called raw ink type ink jet printer, in which the ink 1 is stored in a free state without being held by an ink occlusion body such as a fiber bundle, and the housing is Basically, it comprises a box portion 2, an ink tank passage forming member 3 and a lid body 4. The box portion 2 is an injection-molded product of polypropylene synthetic resin having excellent transparency and transparency of the ink 1. The remaining amount of the ink 1 is visible, and the ink 1 and the liquid stopper 6 are inside. It is housed and arranged to form an ink chamber. The box portion 2 has an ink ejection portion 2a connected to the print head on one side, and the ink ejection portion 2a has a slit 5 having a single letter shape.
This is an elastic valve 5 having a, and the slit 5a is opened at the time of connection with the print head.

An ink passage 3a communicating with the ink discharge portion 2a is formed inside the box portion 2 by an ink tank passage forming member 3. The ink tank passage 3a has an opening 8 at an uppermost position as an ink storage chamber as an inlet for the ink 1, and keeps a negative pressure in the ink storage chamber by the weight of the liquid stopper 6. In addition, the ink passage 3a
Is set so that the distance from the inner wall of the box portion 2 is 1 mm, and even if the ink 1 in the box portion 2 is reduced and the ink 1 is only in the ink tank passage 3a, the ink tank passage Capillary force acts on 3a itself so that ink ejection is unlikely to be hindered and ink dripping or leakage during printing is prevented.

The liquid stopper 6 has, for example, a viscosity of 541,000 mP · s and a surface tension of 57 mN, which is gelled by a gelling agent.
/ M and the contact angle with the inner wall of the box 2 is 73 °. A support 7 which is an injection-molded product of polypropylene resin is placed by being immersed in the liquid stopper 6.
This is because when the inner diameter of the box portion 2 is large, the cross-sectional area of the box portion 2 and the area of the ink interface are large, so the interface maintenance function of the liquid stopper 6 is more reliable against vibration during transportation and impact upon dropping. This is because Here, in order to prevent the support 7 from moving into the ink or coming out of the layer of the liquid stopper 6, a polypropylene synthetic resin having a specific gravity of 0.89 with respect to the specific gravity of 0.90 of the liquid stopper 6. It is made of injection molded products.

[0009]

As described above, according to the present invention, it is possible to obtain the one in which the problems of evaporation and backflow of ink and defective ejection of ink are suppressed as much as possible.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example.

[Explanation of symbols]

1 ink 2 boxes 3 Ink tank passage forming member 3a Ink tank passage 4 Lid 4a atmosphere communication hole 5 Elastic valve 5a slit 6 liquid stopper 7 Support 8 openings

Claims (5)

[Claims] 1. An ink outlet for accommodating ink in a free state and for discharging the ink in accordance with a suction force of an ink suction means is arranged at an upper portion of an ink storage chamber that opens downward, and an ink outlet is provided at a lower position of the ink. An ink storage / outflow structure in which a fluid stopper that moves in accordance with the interface movement due to a decrease in the volume of ink stored in contact with ink is arranged and the ink storage chamber is sealed. 2. A valve is provided between the ink suction means and the ink outlet to allow ink to flow out by opening with the suction force of the ink suction means. The ink storage / outflow structure according to claim 1, wherein the ink tank cartridge is detachable from the main body of the ink discharge structure. 3. The ink storage / outflow structure according to claim 2, wherein an ink holding portion is arranged inside the valve. 4. The ink accommodating / outflow structure according to claim 1, further comprising a support that is at least partially immersed in the fluid stopper. 5. The ink storage / outflow structure according to claim 1, wherein the viscosity of the liquid stopper is 100 mPa / s or more and 1,000,000 mPa / s or less (25 ° C.).