JPS61286141A - Liquid filling method for ink drip jet device - Google Patents

Abstract

PURPOSE:To reduce the quantity of the dissolved gas dissolved in a filling fluid to prevent the generation of bubbles, by substituting a deaired second filling fluid for a gas-dissolved first filling fluid in an ink drop jet device. CONSTITUTION:After being filled with a first filling fluid subjected to the treatment for facilitating the gas-dissolution, an ink drop jet device 1 is left to stand for a predetermined time to allow the bubbles remaining therein to dissolve in the first filling fluid. Thereafter, a filling fluid tank 22 is connected to the jet device 1 by a selector 23 to flow a deaired second filling fluid stored in the filling fluid tank 22 into the jet device 1, and in the meanwhile, solenoid valves 17 are opened to discharge the first filling fluid outside therethrough, thus substituting the second filling fluid for the first filling fluid. In this manner, the dissolved gas in the filling fluid results in decreasing in quantity, avoiding the generation of bubbles even if the saturated solubility of gas in the filling fluid lowers due to a change in temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION C1 Field of Industrial Application The present invention relates to an ink droplet ejecting device used in an inkjet printer that prints desired characters such as letters, figures, or graphics using a collection of minute ink droplets. This invention relates to a liquid filling method.

(b) Conventional technology Displacement of the ink chamber due to minute vibrations of the pressure lightning agitation plate, etc.? An ink droplet ejecting device that ejects ink droplets with a diameter of about 50 to 100 μm has a small displacement as described above, and therefore, once air bubbles enter the ink chamber, the ink droplet ejection operation is inhibited.

Therefore, it is required to fill the ink chamber of the ink droplet ejecting device immediately after manufacture without introducing air bubbles into the ink chamber. Conventionally, such ink filling was disclosed in Japanese Patent Application Laid-open No. 51-2.
Publication No. 1439 C: As disclosed, in a state where the ink supply port of the ink droplet ejecting device and the ink tank are directly connected,
This was done by forcibly reducing the pressure from the ink nozzle from which the ink droplets were to be ejected.

However, in recent years, along with the demand for higher resolution, the internal structure of ink droplet ejecting devices has tended to become more complex and detailed.
It becomes difficult to fill the ink reliably, causing a decrease in yield.

(C) Problems to be Solved by the Invention The present invention attempts to solve these drawbacks, namely, minute displacement C: obstructs the ink droplet ejecting operation of the ink droplet ejecting device that ejects the ink droplets. The purpose is to fill liquid without leaving any air bubbles and to reduce the amount of dissolved gas in the filling liquid to eliminate the generation of air bubbles.

(b) Means for Solving the Problems The present invention is characterized in that an ink droplet ejecting device is filled with a first filling liquid treated to easily dissolve gas, and the gas in the ink droplet ejecting device is transferred to the first filling liquid. After the ink droplet is dissolved in the filling liquid, the inside of the ink droplet ejecting device is replaced with a second filling liquid that is deaerated from the first filling liquid.

(E) Effect As mentioned above, the remaining air bubbles are dissolved in the filling liquid, and the filling liquid with these bubbles dissolved is replaced with the degassed filling liquid, so the temperature changes and the saturated solubility of the gas decreases. There is also no risk of air bubbles forming within the ink drop ejector.

(f) Example FIG.
This is a conceptual diagram when applied to the on-demand type metal diaphragm type ink droplet ejecting device (11) disclosed in the publication, and (2) is a conceptual diagram when applied to the on-demand type metal diaphragm type ink droplet ejecting device (11) disclosed in the publication. (3) is a horn-shaped displacement amplification chamber that amplifies the minute displacement of the vibrator (2) via the vibration propagation liquid; (4) is a metal diaphragm that vibrates in response to the amplified minute displacement; 5) is an ink chamber whose volume increases or decreases due to rapid minute displacement of the diaphragm (4), and ink is supplied to this ink chamber (5) via an ink supply pipe (7) brazed to the helad body (6). (8) is an ink nozzle that ejects the retained ink as ink droplets when the diaphragm (4) is displaced in a direction that reduces the volume of the ink chamber (5); An air nozzle is coaxially bored between the ink nozzle (8) and an air chamber αα, and an air flow supply snow (11
An air flow is supplied from an external air pump or the like (not shown) through the ink nozzle (8) to surround the ink droplets ejected from the ink nozzle (8) and assist their flight. The mackerel is a pinhole with a minute diameter etched into the metal diaphragm (4), and the ink chamber (5) is caused by the displacement of the metal diaphragm (4) from which ink droplets are to be ejected.
) does not obstruct the flow of ink within the ink.

0 is a pressure reducing means for reducing the pressure of the displacement amplification chamber (3), the ink chamber (5) and the air chamber αC of the ink droplet ejecting device (1) having the above structure, and the pressure reducing means a3 includes a vacuum pump a4 and the vacuum pump Connecting pipes (15a), (151:+), (15c) connecting 0 and each chamber (3), (5), αe, and connecting pipes (15a), (15b), (15c) A first solenoid valve σe and a second solenoid valve aD inserted in the middle of each,
Then, a hole is opened from the spacing body (6) of the ink droplet ejecting device Tll to form each of the displacement amplification chamber (3) and the ink chamber (5).
: Continuous connecting holes (18a) (18b) C above connecting pipe (1
Adapters (19a) and (19b) that enable detachable connection of 5a and 15b.

The first solenoid valve a61 is connected to the vacuum pump I and each chamber (3), (
5) and ao, and the second solenoid valve a port controls the opening and closing operation of each chamber (3), (5), and ao to the outside air.

(211 is an air pump that pumps pressurized air flow, (2z is the displacement amplification chamber (3), ink chamber (5), and air chamber α■
2111 Filling liquid tank (2111 Filling liquid tank (2111))
This is a selector that selects one of the ink chambers 2z and connects it via a connecting pipe Q4) connected to an ink supply pipe (7) connected to an ink chamber (5). Although not shown, a vacuum pump that acts as a defoaming device is connected to the filling liquid tank (22) via a solenoid valve.In other words, by reducing the pressure in the filling liquid tank (22+) with the vacuum pump, the inside of the tank is The filling liquid contained in the container is deaerated to facilitate the dissolution of air bubbles.

As shown in Figure 1, immediately after the manufacture of the ink droplet ejecting device (11), only air exists in the internal chambers (3), f51, (IG), and in such a state, the above Each room (
3), (5), and (11) are filled with a filling liquid such as ink or water. First, prior to filling, the air nozzle (9) is placed on the tape and sealed in a liquid-tight manner.

Next, with the first solenoid valve (161 closed), the second solenoid valve (17) is opened, and the air supply pump (211) and the ink chamber (5) are brought into communication by selecting the selector. This state When the air supply pump I211 is operated, the pressurized air flow formed by this air supply pump (211) flows through the connecting pipe (24a), the selector, the connecting pipe @, and the ink supply pipe (
7) and reaches the ink chamber (5).
) The pressurized air flow that enters is divided into three directions. That is, the first branch flow is connected to the connecting hole (18) which directly communicates with the ink chamber (5).
b), adapter (19b), connecting pipe (15b) to the second
flows through the thread path connecting the magnetic valve (171), and the second branch flows through the ink chamber (5), the pinhole (1z), the displacement amplification chamber (3), the connecting hole (18a), the adapter (19a), and the connecting tube (15a). )
The third branch flow reaches the second solenoid valve σn+ from the ink chamber (5), the ink nozzle (8), the air chamber (11° air supply pipe αD1 connection pipe (15c)) and the second solenoid valve 1n. Therefore, the pressurized air flow starting from the air supply pump (211) reaches each chamber (3), (5), 0 of the ink drop ejector (1).
ω and is emitted into the atmosphere from the second electromagnetic valve surface, and each chamber (3), (51, fi (I
The inside is pre-cleaned.

When the inside is cleaned, the operation of the air supply pump Q11 is stopped and the outlet of the selector ■ is closed, that is, the air supply pump (21
1 filling liquid tank (2'J) is all unselected, the first solenoid valve σB is opened and the second solenoid valve (17) is closed. In this state, the vacuum pump fi41 is operated and the connecting pipe (15a ), (15b), (15c), adapter (
19a), (19b), the pressure of the displacement amplification chamber (3), ink chamber (5), and air chamber αG in the ink droplet ejecting device (11), which are communicated via the air supply pipe αυ, is reduced.

After reducing the pressure to a predetermined pressure, the vacuum pump I is temporarily stopped and the selector, which is in the closed state, is switched to communicate the filling liquid tank (22+) and the ink droplet ejecting device (11).

At this time, the filling liquid stored in the filling liquid tank is
For example, the first filling liquid is water that has been deaerated to make it easier to dissolve gases. The fill liquid tank (
221 is selected to communicate with the ink droplet ejecting device (11), the first filling liquid contained in the filling liquid tank is transferred to the displacement amplification chamber (3) and the ink chamber (5) in a reduced pressure state.
, the air chamber αυ is filled based on the pressure difference. What should be noted in this filling liquid operation is that the first filling liquid to be filled has been treated to easily dissolve gas. Therefore, provisional C; each chamber (3), (5), which should be filled with the filling liquid;
(Since the structure of 111I is complex and fine, even if a few air bubbles remain after filling with the filling liquid, the solubility of the filling liquid is high, so the bubbles will dissolve in the filling liquid.

In this way, after filling the ink droplet ejecting device (11) with the first filling liquid, the ink droplet ejecting device (11) is filled with the filling liquid in order to dissolve the remaining air bubbles in the ink droplet ejecting device (1) into the filling liquid. (1) is left for a predetermined period of time.

After that, the ink droplet ejecting device (1) and the filling liquid tank are made to communicate with each other using the selector (■), the second solenoid valve αη is opened, and the air contained in the filling liquid tank is degassed by pressurization or pressure difference. The treated second filling liquid, such as water, ink, or glycol, is poured into the ink droplet ejecting device (11), and the first filling liquid is discharged to the outside via the second electromagnetic valve, and the second filling liquid is mixed with the first filling liquid. Replace with the second filling liquid.

When the inside of the ink droplet ejecting device (1) is replaced with the second filling liquid, there is very little gas dissolved in this filling liquid, so the temperature changes and the saturated solubility of the gas in the filling liquid decreases. However, no bubbles are generated.

In addition, air bubbles remaining in the ink droplet ejecting device [1]
If the solution is not sufficiently dissolved in the filling liquid, it will also be dissolved in the replaced filling liquid, so replacement may be performed multiple times as necessary.

C. In the above embodiment, prior to filling with the first filling liquid, cleaning was carried out by supplying a flow of pressurized air into the ink droplet ejecting device (1). When performing maintenance on the filled ink droplet ejecting device (11) or when air bubbles are generated, when refilling the ink droplet ejecting device (11) with the filling liquid, perform two steps C to ensure that the previously filled filling liquid is discharged to the outside. As well as drying the inside thereof, filling operation with new filling liquid can be facilitated.

(Effects of the Invention) As is clear from the above explanation, the filling method of the present invention is capable of removing C2 bubbles even if they remain during filling with the filling liquid because the bubbles are dissolved in the filling liquid. By replacing the filling liquid with one that has a small amount of dissolved gas, the generation of bubbles can be prevented even when the temperature changes, and there is no risk of interfering with the ejection operation of ink droplets.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the liquid filling method of the present invention. 1... Ink droplet ejecting device, 3... Displacement amplification chamber, 5
... Ink chamber, 10-- Air chamber, 13-- Depressurizing means, 22-- Filling liquid tank, 23-- Selector.

Claims (1)

[Claims] (1) A liquid filling method for an ink droplet ejecting device that ejects ink droplets by minute displacement, in which the first filling liquid treated to easily dissolve gas is filled into the ink droplet ejecting device,
After the gas in the ink droplet ejecting device is dissolved in the first filling liquid, the inside of the ink droplet ejecting device is replaced with a second filling liquid that is deaerated from the first filling liquid. A liquid filling method in an ink droplet ejecting device.