JPH1191122A - Ink container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent leakage of ink even if the volume of air in an ink con tainer is expanded caused by environmental fluctuation. SOLUTION: A first ink chamber 2 communicating with the atmosphere through an air hole 1a and a second ink chamber 3 having a supply port 6 are provided in an ink container 1. A flexible ink bag 4 is suspended from the ceiling into the first ink chamber 2. A region in the second ink chamber 3 is filled with an absorber 7 exhibiting affinity to ink and the remaining region is filled with ink 5. The ink bag 4 communicates with the second ink chamber 3 through a conduction hole 8 provided with a valve mechanism 9 comprising a conical plug 9a for opening/closing the conduction hole 8 and a spring 9b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink storage container for holding ink by a negative pressure generated therein and supplying ink to an ink jet head.

[0002]

2. Description of the Related Art Generally, an ink storage container holds ink by keeping the inside thereof at a constant negative pressure. Various types of negative pressure type ink storage containers have been proposed. For example, a type in which the entire ink storage container is filled with an ink-philic absorbent, a type in which the ink storage container has a room filled with the absorber and a room filled only with ink, or a type of negative pressure instead of the absorber There is a type in which an ink storage container is entirely filled with ink, which includes an adjustment mechanism.

In a type of ink storage container provided with an absorber, ink is impregnated into the absorber and the inside of the ink storage container is maintained at a constant negative pressure by the capillary force of the absorber. In a type of ink storage container having a negative pressure adjusting mechanism, a negative pressure adjusting mechanism is provided in an air hole formed in the ink storage container to maintain a constant negative pressure inside the ink storage container.

[0004] And, any type of ink storage container,
The volume of air consumed by printing is taken into the ink storage container to adjust the negative pressure in the ink storage container.

[0005]

As described above, in the conventional ink storage container, as described above, air corresponding to the volume of consumed ink is taken into the ink storage container. When the air volume in the ink storage container expands due to a rise in temperature or the like, the negative pressure in the ink storage container decreases, and the ink storage container may not be able to hold ink. In this case, the ink that could not be retained leaked from the air holes and the print head.

[0006]

Means for Solving the Problems To solve the above problems, a solution taken by the present invention is to provide a first ink chamber communicating with the atmosphere inside an ink storage container, and a first ink chamber. A flexible ink bag for storing ink, a supply port for supplying ink to the inkjet head, a second ink chamber filled with ink, and a second ink chamber filled with ink. An ink-absorbing member disposed in the ink chamber, an ink passage communicating the ink bag with the second ink chamber, and an ink bag disposed in the ink passage and opening and closing the ink passage to form an ink bag and a second ink passage. And a valve mechanism for reducing the pressure difference between the ink chamber and the ink chamber.

According to the above-described solution, when ink is consumed by printing, the negative pressure in the second ink chamber increases,
A pressure difference occurs between the ink bag and the ink bag. At this time, the valve mechanism opens the ink passage and puts the ink in the ink bag into the second ink chamber to reduce the pressure difference. Also, when the ink in the ink bag flows into the second ink chamber and the ink bag shrinks, air enters between the inner wall of the first ink chamber and the ink bag. When the pressure difference between the second ink chamber and the ink bag disappears, the valve mechanism closes the ink passage.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. Elements common to the drawings are denoted by the same reference numerals. FIG. 1 is a schematic sectional view of an ink storage container according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA of the ink storage container of FIG. 1, and FIG.
FIG. 2 is a diagram illustrating a state in which the ink storage container is filled with ink, and FIG. 2B is a diagram illustrating a state in which the ink in the ink storage container is low.

An ink storage container 1 (hereinafter referred to as an ink tank 1)
) Is a negative pressure type ink tank, in which a first ink chamber 2 is provided above and a second ink chamber 3 is provided below. The first ink chamber 2 is formed with an air hole 1a having a size through which air can easily enter and exit. Further, the first ink chamber 2 includes a flexible ink bag 4. The ink bag 4 is fixed to the ceiling of the first ink chamber 2 with an adhesive or the like at one ridge line, and is suspended from the ceiling. This ridge line is desirably in a direction parallel to the long side when the ceiling of the ink tank 1 has a substantially rectangular shape. The ink bag 4 is filled with the ink 5 in a state where no air is mixed therein. When the ink 5 is consumed by printing, the air corresponding to the consumed ink volume is supplied from the air hole 1a to the first ink chamber. 2 between the inner wall and the ink bag 4.

The second ink chamber 3 has a substantially concave shape, and has a supply port 6 formed therein. One half area of the second ink chamber 3 on the side of the supply port 6 is provided with an absorbent 7 having ink affinity.
And the other half area is filled with the ink 5 in a state where no air is mixed therein. The absorber 7 is filled with the ink 5 in a substantially saturated state, and the capillary force of the absorber 7 keeps the second ink chamber 3 at a constant negative pressure. An ink channel (not shown) is connected to the supply port 6, and ink is supplied to an inkjet head (not shown) via the ink channel.

The ink bag 4 and the second ink chamber 3 communicate with each other through a cylindrical communication hole 8 serving as a passage for the ink 5. A valve mechanism 9 is provided in the communication hole 8. Valve mechanism 9
Is a conical plug 9a that can open and close the communication hole 8 on the second ink chamber 3 side, and a spring 9b that pulls the plug 9a in the direction of arrow B.
It has. The spring 9b of the valve mechanism 9 is connected to the first ink chamber 2
In this embodiment, the ink bag 4 side of the communication hole 8 is narrower than the second ink chamber 3 side by the fixed area.

When there is no pressure (negative pressure) difference between the ink bag 4 and the second ink chamber 3, the tension of the spring 9b pulls the plug 9a in the direction of arrow B to close (close) the communication hole 8, When the negative pressure of the second ink chamber 3 becomes higher than the negative pressure of the ink bag 4, the stopper 9a is pulled in the direction of arrow C by this negative pressure to open the communication hole 8.

In the ink bag 4 and above the communication hole 8,
A hollow cylinder 10 is provided. One end of the cylinder 10 is in contact with the ceiling of the ink bag 4, and the other end is connected to the communication hole 8. A plurality of holes 10a are formed on the side surface of the cylinder 10, and when the ink 5 is filled in the ink bag 4, these holes 1a are formed.
The ink 5 enters the cylinder 10 from 0a, and the inside of the cylinder 10 is also filled with the ink 5. The liquid level of the ink 5 in the cylinder 10 does not change due to the capillary force even if the amount of the ink 5 in the ink bag 4 is reduced.

As can be seen from FIG.
The (first ink chamber 2) has a larger capacity than the second ink chamber 3, and therefore, the ink bag 4 stores a larger amount of ink than the second ink chamber 3.

Here, the pressure P applied to the valve mechanism 9 will be described. The pressure shown in the following equation is applied to the valve mechanism 9. P0 is the atmospheric pressure, ρ is the specific gravity of the ink 5, g
Represents the gravitational acceleration, and h represents the liquid level of the ink 5 in the ink bag 4. From the formula, the pressure P applied to the valve mechanism 9 changes only with the liquid level h of the ink 5 in the ink bag 4. I understand.

P = P0 + ρ · g · h (1) As described above, the ink bag 4 is suspended from the ceiling of the first ink chamber 2 and the cylinder 1
Even if the ink 5 in the ink bag 4 gradually decreases due to the capillary force of 0, the height h does not change until the ink 5 is almost exhausted, as shown in FIG. That is, the pressure P applied to the valve mechanism 9 does not change until the ink 5 in the ink bag 4 is almost exhausted.

Next, changes accompanying the printing operation of the ink tank 1 of the present embodiment will be described with reference to FIGS.

Each time the ink jet head ejects the ink 5 in the printing operation, the ink 5 in the second ink chamber 3
Is sucked toward the ink jet head, discharged from the supply port 6, and supplied to the ink jet head through the ink flow path. The negative pressure of the second ink chamber 3 becomes larger than the negative pressure of the ink bag 4 by the amount of the ink 5 discharged from the second ink chamber 3. Therefore, a difference is generated in the internal pressure between the second ink chamber 3 and the ink bag 4, and the stopper 9a is pulled in the direction of arrow C against the urging force of the spring 9b.

When the plug 9a is pulled, the communication hole 8
Is opened, and the ink 5 in the ink bag 4 flows into the second ink chamber 3 due to the negative pressure in the second ink chamber 3. As a result, the internal pressure of the second ink chamber 3 is reduced, and the pressure difference between the second ink chamber 3 and the ink bag 4 disappears. When the pressure difference disappears, the plug 9a is pulled in the direction of arrow B by the urging force of the spring 9b, and closes the communication hole 8. Therefore, the ink bag 4
Does not flow into the second ink chamber 3.

The ink 5 in the ink bag 4 is stored in the second ink chamber 3.
2A, the ink bag 4 changes (shrinks) from the state shown in FIG. 2A to the state shown in FIG. 2B, and the volume of the ink 5 consumed from the ink bag 4 Almost the same amount of air is taken into the first ink chamber 2 from the air hole 1a.

When the air in the first ink chamber 2 expands due to an environmental change, excess air is released from the air hole 1a.

In the present embodiment, the valve mechanism 9 operates to open and close the communication hole 8 to reduce the pressure difference between the second ink chamber 3 and the ink bag 4, so that the ink tank 1 4 can be used until the ink 5 is almost exhausted.

In this embodiment, by adjusting the tension of the spring 9b of the valve mechanism 9 according to the height h of the ink bag 4, the amount of the ink 5 stored in the first ink chamber 2 can be adjusted to a desired amount. Can be set to That is, the ink 5 absorbed by the absorber 7
The amount of ink in the ink bag 4 can be set regardless of the amount of ink and the amount of ink 5 in the second ink chamber 3. Conventionally, for example, when a type in which the ink tank was filled with an absorber was used, the height of the ink tank was limited because the ink holding force of the absorber was inversely proportional to the height of the volume. In the embodiment, the height of the ink tank 1 is not limited.

Since the valve mechanism 9 operates by the pressure difference between the second ink chamber 3 and the ink bag 4, the valve mechanism 9 may have a simple structure. Therefore, the space for installing the valve mechanism 9 is limited to the plug 9a of the valve mechanism 9.
It is sufficient if there is a space that can operate.

For example, specifically, the space for filling the ink 5 in the second ink chamber 3 may be 15 [mm] in width, 15 [mm] in depth, and 15 [mm] in height.

Further, since the ink bag 4, the communication hole 8, and the second ink chamber 3 are substantially airtight and air does not enter or exit, they are not affected by environmental changes. Therefore,
In one area filled with the absorber 7, the absorber 7 having a size that does not cause a pressure difference between the ink bag 4 and the second ink chamber 3 when the ink tank 1 is not used may be provided. Specifically, width 15 [mm], depth 15 [mm], height 10
[Mm].

That is, in this embodiment, the ink tank 1 having a limited capacity can be filled with the ink 5 to the maximum extent. That is, as the capacity of the ink tank 1 increases, the amount that can be filled with the ink 5 can be made larger than in the conventional configuration.

Further, since the air does not flow into and out of the ink bag 4, the communication hole 8, and the second ink chamber 3, the ink 5 in the second ink chamber 3 is absorbed by the absorber 7 by the expansion of the air generated due to the environmental change. Does not leak out of the supply port 6 when the ink 5 flows into the supply port 6 and cannot be completely absorbed by the absorber 7.
Further, even if the air in the first ink chamber 2 expands due to an environmental change, the air is released from the air hole 1a by the expanded amount.
The inflated air does not compress the ink bag 4.

In this embodiment, since the ink 5 in the ink tank 1 does not come into contact with air, the deterioration of the ink 5 due to the absence of printing for a long time does not occur.

In the present embodiment, the pressure applied from the ink 5 in the ink bag 4 to the valve mechanism 9 can be always kept constant by suspending the ink bag 4 from the ceiling of the first ink chamber 2. Therefore, the ink tank 1 can hold the ink with a substantially constant holding force. Therefore, the ink tank 1 can stably supply the ink 5 to the inkjet head.

In the present embodiment, one region of the second ink chamber 3 is filled with the absorber 7 and the remaining region is filled with the ink 5.
However, the second ink chamber 3 may be entirely filled with the absorber 7. In this case, a space in which the stopper 9a of the valve mechanism 9 can operate may be formed in the absorber by notches or the like.

[0032]

As described in detail above, the present invention provides
A flexible ink bag is fixedly disposed in a first ink chamber communicating with the atmosphere, and an ink-philic absorber is disposed in a second ink chamber filled with ink. By disposing a valve mechanism for reducing a pressure difference between the ink bag and the second ink chamber in an ink passage communicating the ink chamber and the second ink chamber, the ink is stored by an environmental change such as a rise in ambient temperature. Even if the volume of air in the container expands, ink does not leak from the ink storage container.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an ink storage container according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of the ink storage container of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink storage container 1a Air hole 2 1st ink chamber 3 2nd ink chamber 4 Ink bag 5 Ink 6 Supply port 7 Absorber 8 Communication hole 9 Valve mechanism

Claims (5)

[Claims] 1. An ink storage container for holding ink by a negative pressure generated therein and supplying ink to an ink jet head, comprising: a first ink chamber communicating with the atmosphere; and a part in the first ink chamber. A flexible ink bag that is fixedly arranged and stores ink; a second ink chamber filled with ink formed with a supply port for supplying ink to the ink jet head; and a second ink chamber filled with ink. An ink-absorbing member disposed; an ink passage communicating the ink bag with the second ink chamber; and an ink passage disposed in the ink passage. And a valve mechanism for reducing a pressure difference between the second ink chamber and the second ink chamber. 2. The ink supply device according to claim 2, wherein the valve mechanism includes a stopper that can open and close the ink passage, and an elastic member that holds the stopper and expands and contracts by an internal pressure between the ink bag and the second ink chamber. 2. The ink storage container according to claim 1, wherein when the negative pressure of the chamber becomes larger than the negative pressure of the ink bag, the stopper opens the ink passage by the elastic member to connect the ink bag to the second ink chamber. 3. The second ink chamber has one area filled with the ink-philic absorbent, and the other area filled with ink. The ink path is filled with ink in the second ink chamber. 3. The ink storage container according to claim 2, wherein the ink storage container communicates with the filled area. 4. The ink storage container according to claim 3, wherein said ink bag is fixed to a ceiling of said first ink chamber. 5. The ink storage container according to claim 4, wherein a hollow cylinder is provided in the ink bag at a position connected to the ink passage.