JPH07304187A - Ink degassing method - Google Patents

Abstract

PURPOSE:To obtain an ink deaerating method for effectively removing bubbles and dissolved gas in an ink without changing and decomposing the ink composition and without damaging stability by filling an ink bag having gas barrier property with the ink and sealing it, and sealing a lower part of the bag from an upper part of the bag so as to sandwich bubbles while the bag is being erected. CONSTITUTION:Immediately after an ink bag is filled with an ink, sealed, and heated, secondary sealing is performed by sealing a lower part (j) of the ink bag from an upper seal of the ink bag so as to sandwich bubbles (i) together with the ink (b) while the ink bag (a) is being erected so as to discharge the bubbles in the bag. In order to eliminate irregularities in the discharge quantity and the quantity of the ink in the ink bag, a bag thickness adjusting jig (k) is used at the time of the secondary sealing. After the secondary sealing, a side 1 at an upper end of the bag confining bubbles may remain attached to the bag body, or it may be cut off. As a means for confirming quantities of dissolved gas and the bubbles in the ink bag, when the dissolved gas is air, quantity of dissolved oxygen is measured by using a dissolved oxygen meter on the market so as to estimate entire quantity of air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink degassing method,
More specifically, it relates to an ink degassing method for ink jet recording ink.

[0002]

2. Description of the Related Art The ink jet recording method is easily affected by bubbles and dissolved gas in the ink. Especially, the ink jet recording method using the piezo method is confined in a dissolved gas such as air dissolved in the ink or a container. There is a problem that an abnormal ejection is often caused by the bubbles that are present. Therefore, proposals have been made to remove dissolved gas in the ink and prevent bubbles from being trapped in the container.

For example, JP-A-52-74406 and JP-A-53-61412 disclose that oxygen is removed from air dissolved in an ink by dissolving an oxygen scavenger in an aqueous ink. By doing so, a method of reducing the amount of dissolved gas has been proposed. JP 62-1210
In Japanese Patent Laid-Open No. 62-62, there is proposed a method for manufacturing an ink cartridge for an inkjet printer, in which highly deaerated ink is vacuum-packed under a higher vacuum at the time of filling. JP-A-2
No. 91165 discloses an ink manufactured by using a manufacturing apparatus equipped with a heating means and a reflux means, at 70 ° C. after degassing.
There is proposed a method for producing an inkjet recording ink, which has a step of controlling the heating means so that the amount of nitrogen generated during the 160 hours in the environment is 2 to 10 ppm.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the methods described in JP 406 and JP-A-53-61412, only the oxygen can be removed by the oxygen absorber, the dissolved gas cannot be completely removed, and the oxygen absorber or the oxygen absorber is oxygen. However, there is a problem in that the reaction product after being oxidized by the composition adversely affects the stability of the ink. The method described in Japanese Patent Application Laid-Open No. 62-121062 has a problem that the ink composition is likely to change due to evaporation of the low boiling point ink component due to high deaeration. JP-A-2-
In the method described in Japanese Patent No. 91165, heating at a high temperature of 80 ° C. or higher and subsequent heating at 70 ° C. for 160 hours,
There is a problem that not only evaporation of the low boiling point component but also deterioration of the ink is likely to occur.

The problem to be solved by the present invention is to provide an ink degassing method for effectively removing air bubbles and dissolved gas in the ink without changing the ink composition or degrading the ink and without impairing the stability of the ink. To provide.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have solved the present invention.

That is, in order to solve the above problems, the present invention fills an ink bag having a gas barrier property with ink,
Provided is an ink deaeration method in which after sealing, an ink bag is stood up and air bubbles are sandwiched between the upper part and the lower part of the ink bag.

In the method of the present invention, further, (1) a bag thickness adjusting jig is used in the above-described ink deaeration method in which the ink bag is erected and sealed so that air bubbles are sandwiched between the upper part and the lower part of the ink bag. Use, (2) filling and sealing the ink in the ink bag, then heating the ink bag to 50 ° C. or higher, and sealing the air bag from the upper part to the lower part while sandwiching the ink bag, (3) Filling and / or sealing the ink in the ink bag under reduced pressure below atmospheric pressure at room temperature. (4) Filling the ink bag with ink below atmospheric pressure, preferably below 50 mmHg at room temperature. And / or sealing, and (5) filling and / or sealing the ink in the ink bag with the temperature of the ink being 5 at normal pressure.
By heating at 0 ° C. or higher, preferably at 50 ° C. or higher and lower than 70 ° C., the ink can be degassed more effectively.

The structure of the present invention will be described below in detail with reference to the drawings.

The ink bag a having a gas barrier property of the present invention shown in FIG. 1 has, for example, a heat-weldable plastic material such as polyethylene (PE) or polypropylene (PP) on the inner surface and polyethylene terephthalate (PET) on the outer surface.
Consists of a laminate film of two or more layers of plastic materials with excellent gas barrier properties such as nylon, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol,
A laminate film having a layer of a metal foil such as aluminum or a metal vapor deposition film between the inner surface and the outer surface is preferable.

The ink b filled in the ink bag may be either a water-based ink or an oil-based ink containing a low boiling point or high boiling point organic solvent as a main solvent.

The filling c of the ink into the ink bag does not require deaeration of the ink in advance, but it is preferable to use a conventionally known deaeration means such as heating or decompression to prepare the ink composition. Ink degassing d may be performed in advance to the extent that there is no change. The heating temperature at this time is preferably 50 ° C. or higher, and the reduced pressure is more preferably 50 mmHg or lower.

The ink outlet e is plugged with, for example, a rubber material or a rubber material held by a plastic molding, and when the ink cartridge is set in the printer, the ink is sucked out by a suction needle provided on the printer side. You can It is more preferable that the rubber stopper and the ink in the bag are partitioned by the plastic molded product of the outlet because high sealability is maintained when the ink cartridge is unused.

Sealing of the ink bag a after filling the ink bag shown in FIG. 2, that is, the upper seal f is performed by a sealing method such as impulse sealing or heat sealing, but the sealing may be performed at room temperature and atmospheric pressure. However, it is desirable to carry out at room temperature under atmospheric pressure or less, more preferably under vacuum g of 50 mmHg or less. The depressurized seal under heating tends to cause boiling of the ink and is not always preferable.

Heating of the ink bag a after sealing the ink bag of FIG. 3 is carried out by using a thermostatic device h or the like, and the temperature thereof is preferably 50 ° C. or more and less than 70 ° C. under normal pressure. As a result, the gas dissolved in the ink is generated as bubbles i in the ink bag. When the heating temperature after sealing the ink bag is less than 50 ° C., even if the bubbles are expelled from the ink bag, the dissolved gas is likely to become bubbles during storage, which causes ink ejection failure. 70
At temperatures above ℃, the deterioration and deterioration of the ink bag becomes remarkable.

In the heating of the ink bag after sealing the ink bag, if the heating time is short, the bubbles of the dissolved gas are insufficiently generated, causing cavitation due to vibration of the piezo element at a high driving frequency, and long-term bagging ink. When stored or stored in a hot place, the dissolved gas remaining in the ink becomes bubbles and causes ejection failure.
It is desirable to perform the heating for 3 hours or more in the heating temperature range of 0 ° C. However, when ink is heated at high temperature for a long time,
Since the quality of the ink itself and the quality of the bag container are affected, it is preferable to keep the heating time within 200 hours under heating conditions of 50 ° C or higher and lower than 70 ° C.

When a highly volatile substance is contained as an ink component, it is difficult to perform degassing operation in advance, but degassing without changing the ink composition by heating and secondary sealing of the ink bag after sealing the ink bag Is possible.

In the so-called secondary seal of FIG. 4, after the ink bag is filled with ink, sealed and heated, the ink bag a is immediately raised while the ink seal b is erected and the portion j below the ink seal b is bubbled along with the ink b. A secondary seal is inserted so as to sandwich the ink and the air bubbles in the ink bag are expelled. In order to eliminate variations in the amount of bubbles expelled from the ink bag and the amount of ink in the ink bag, it is advisable to use a bag thickness adjusting jig k as shown in FIG. 5 at the time of secondary sealing.

After the secondary sealing, the side 1 of the upper end of the bag in which air bubbles are trapped may be left attached to the bag body or may be separated.

As a means for confirming the amount of dissolved gas and bubbles in the ink bag, air is a problem in most inks. When the air dissolved gas is air, the dissolved oxygen is measured using a commercially available dissolved oxygen meter. The simplest method is to measure the volume and estimate the total volume of air. In case of other gases, it is possible to analyze directly with ink if instrumental analysis is possible, but for general gases, the amount of gas generated by heating the ink in a sealed system by utilizing the solubility decrease phenomenon due to heating. Can also be measured.

Further, the ink jet printer using the piezo method is very susceptible to the influence of dissolved gas and bubbles, and in particular, when continuous jetting is performed, an ink ejection failure phenomenon occurs due to the influence of dissolved gas and bubbles. The continuous injection test using is an effective means to investigate the degassing effect, and is practical.

[0022]

EXAMPLES Next, the present invention will be described more specifically with reference to ink examples, examples and comparative examples.

(Ink Example 1) C. I. Solvent Black 43 8.0 parts by weight Jonkryl 682 11.0 parts by weight (Johnson Polymer styrene acrylic acid copolymer resin) Dibutyl sebacate 1.0 parts by weight Ethanol 80.0 parts by weight The above composition is sufficiently stirred, After dissolution, this solution was
Filtration was carried out using a 5μ membrane filter without degassing operation to obtain an ink used in this example.

(Ink Example 2) C. I. Direct Blue 199 1.5 parts by weight Diethylene glycol 3.0 parts by weight Isopropyl alcohol 5.0 parts by weight Ion-exchanged water 90.5 parts by weight After the above components are mixed and dissolved, the remaining components are additionally dissolved to obtain a pore size of 0.5 μm. Filtration was performed without deaeration with a membrane filter to obtain the ink used in this example.

Example 1 PET / Aluminum / PE
The ink obtained in Ink Example 1 was filled in an ink bag made of the laminated film of No. 1 at room temperature and normal pressure and sealed using an impulse sealing machine to obtain a bag-filled ink. Next, instead of holding the bag by hand, while holding it with a holder made of a rigid plastic material, the bag is filled with 100 cc of ink by degassing the ink by sealing the upper and lower parts of the bag so that air bubbles are sandwiched. Got

As a result of mounting the ink cartridge containing the bag-filled ink in a hard case on a piezo type ink jet printer and performing continuous ejection, 30 out of 100 ink cartridges failed to eject ink 2 to 3 times in the middle. However, it was possible to eject to the end, and the remaining 70 inks could be ejected to the end without any ink ejection failure.

When the upper portion of the bag of the bag-filled ink in which ink was not ejected was sucked out by a microsyringe, a bubble having a capacity of about 0.03 cc was captured.

(Example 2) PET / aluminum / PE
The ink of Ink Example 1 was filled in an ink bag made of the laminated film of No. 1 at room temperature and normal pressure and sealed using an impulse sealing machine to obtain a bag-filled ink. Next, add 5 bags of ink
The bag was heated at 0 ° C. for 5 hours, and the bag was held by hand. While standing, the bag was filled with 100 cc of ink by degassing the ink by sealing the upper part and the lower part of the bag so as to sandwich air bubbles.

As a result of mounting the ink cartridge containing the bag-filled ink in a hard case on a piezo-type ink jet printer and performing continuous ejection, 50 out of 100 ink cartridges failed to eject ink 2 to 5 times in the middle. However, it was possible to eject to the end, and the remaining 50 inks could be ejected to the end without any ink ejection failure.

When the upper portion of the bag of the bag-filled ink in which ink was not ejected was sucked out by a microsyringe, a bubble having a capacity of about 0.05 cc to 0.1 cc was captured.

Example 3 In Example 2, after heating the bagged ink at 50 ° C. for 5 hours, instead of holding the bag by hand, holding the bag with a holder made of a hard plastic material, The ink was degassed by sealing the portion so as to sandwich air bubbles, and a bag-filled ink containing 100 cc of the ink was obtained.

The ink cartridge containing the bag-filled ink in the hard case was attached to the piezo type ink jet printer and the continuous jetting was performed. As a result, 10 out of 100 ink cartridges failed to eject the ink 2 to 5 times on the way. However, it was possible to eject to the end, and the remaining 90 inks could be ejected to the end without any ink ejection failure.

When the upper portion of the bag of the bag-filled ink in which ink was not ejected was sucked out by a microsyringe, a bubble having a capacity of about 0.02 cc was captured.

Example 4 PET / Aluminum / PE
The ink of Ink Example 2 was filled in an ink bag made of the laminated film of No. 2 at room temperature and normal pressure and sealed under a reduced pressure of 30 mmHg using a vacuum chamber type impulse sealer to obtain a bagd ink. Next, the bag-filled ink is heated at 60 ° C. for 15 hours, and the bag is held by hand. While standing, the bag is filled with 100 cc of ink by degassing the ink from the upper part to the lower part of the bag with air bubbles sandwiched between them. I got the filling ink.

The ink cartridge containing the bag-filled ink in the hard case was attached to the piezo type ink jet printer and the continuous ejection was performed. As a result, one out of 100 ink cartridges failed to eject ink once in the middle. It was possible to eject to the end, and the remaining 99 inks could be ejected to the end without any ink ejection failure.

When the upper portion of the bag of the bag-filled ink in which ink was not ejected was sucked out by a microsyringe, a bubble having a capacity of about 0.01 cc was trapped.

Example 5 PET / Aluminum / PE
The ink of Ink Example 2 was heated at 70 ° C. for 1 hour at normal pressure in an ink bag made of the laminated film of Example 1 and then filled, and sealed using an impulse sealing machine to obtain a bag-filled ink. Next, the bag-filled ink is heated at 60 ° C. for 10 hours, and the bag is held by hand. While standing, the bag is sealed so that air bubbles are sandwiched between the upper part and the lower part of the bag, and the ink is deaerated.
A bagged ink containing cc was obtained.

As a result of mounting the ink cartridge containing the bag-filled ink in a hard case on a piezo-type ink jet printer and performing continuous ejection, 5 out of 100 ink cartridges failed to eject ink 2 to 5 times in the middle. However, it was possible to eject to the end, and the remaining 95 inks could be ejected to the end without any ink ejection failure.

When the upper part of the bag of the bag-filled ink in which the ink was not ejected was sucked out by a microsyringe, bubbles having a capacity of about 0.01 cc to 0.05 cc were captured.

Example 6 In Example 5, after heating the bag-filled ink at 60 ° C. for 10 hours, instead of holding the bag by hand, while holding it with a holder made of a hard plastic material, the part from the top to the bottom of the bag The ink was degassed by sealing so as to sandwich air bubbles, and a bag-filled ink containing 100 cc of ink was obtained.

The ink cartridge containing the bag-filled ink in the hard case was attached to the piezo type ink jet printer, and as a result of continuous ejection, all the ink cartridges out of 100 ink cartridges were not ejected in the middle to the end. Injection was possible.

No bubbles were observed in the bag-filled ink bag.

(Comparative Example 1) PET / aluminum / PE
The ink bag made of the laminated film of No. 1 was filled with the ink of Ink Example 1 at room temperature and normal pressure and sealed using an impulse sealing machine to obtain a bag-filled ink containing 100 cc of ink.

As a result of mounting the ink cartridge containing the bag-filled ink in a hard case on a piezo type ink jet printer and performing continuous ejection, all 100 ink cartridges are frequently ejected in the middle of the ink.
I couldn't jet until the end.

When the upper portion of the bag of the ink containing the ink that has not ejected is sucked out by a syringe, the capacity is about 0.5 cc.
1 cc of air bubbles were trapped.

(Comparative Example 2) PET / aluminum / PE
The ink of the ink example 2 was filled in an ink bag made of the laminated film of No. 2 at room temperature and normal pressure and sealed using an impulse sealer to obtain a bag-filled ink containing 100 cc of ink.

As a result of mounting the ink cartridge containing the bag-filled ink in a hard case on a piezo type ink jet printer and performing continuous ejection, all 100 ink cartridges frequently fail to eject ink on the way,
I couldn't jet until the end.

When the upper part of the bag of the ink-filled bag in which ink was not ejected was sucked out by a syringe, the capacity was about 0.5 cc.
1 cc of air bubbles were trapped.

[0049]

The ink can be effectively removed by filling the ink bag having the gas barrier property with the ink, sealing the ink bag, and then sealing the ink bag while raising the ink bag so that air bubbles are sandwiched between the upper part and the lower part of the ink bag. You can be careful.

A more effective deaeration can be performed by using a bag thickness adjusting jig when the upper and lower parts of the ink bag are sealed while air bubbles are sandwiched while the ink bag is being raised.

After filling the ink bag having a gas barrier property with the ink and sealing the ink bag, the ink bag is heated to 50 ° C. or higher,
The ink can be degassed more effectively when the ink bag is stood up and sealed so that air bubbles are sandwiched between the upper part and the lower part of the ink bag.

If the ink filling and / or sealing is reduced to atmospheric pressure or less at room temperature to degas the ink, more effective degassing becomes possible.

If the ink filling and / or sealing is performed at room temperature, preferably 50 mmHg or less, or while heating the ink temperature to 50 ° C. or more under normal pressure, more effective degassing is possible. .

Heating the ink bag after sealing the ink bag is preferably carried out at 50 ° C. or higher and lower than 70 ° C. to achieve effective deaeration and to minimize the influence on the ink and the ink bag. Is possible.

[Brief description of drawings]

FIG. 1 is a schematic view showing an ink bag used in the present invention and a step of filling the ink bag with ink.

FIG. 2 is a schematic diagram showing a process of sealing an ink bag.

FIG. 3 is a schematic diagram showing a heating process of an ink bag and bubbles generated in the bag by heating.

FIG. 4 is a front view of the ink bag after the secondary sealing.

FIG. 5 is a side view of a bag thickness adjusting jig k and a side view of an ink bag after secondary sealing using the jig.

[Explanation of symbols]

 a ink bag b ink c filling port d degassing e ink ejection port f upper seal part g vacuum system h constant temperature device i bubble j secondary seal part k bag thickness adjusting jig l bubble confinement part

Claims (7)

[Claims] 1. An ink degassing device, comprising filling an ink bag having a gas barrier property with ink and sealing the ink bag, and then sealing the ink bag so that air bubbles are sandwiched between the upper part and the lower part of the ink bag while standing up. Method. 2. The ink deaeration method according to claim 1, wherein a jig for adjusting the bag thickness is used when the ink bag is sealed and the lower part of the ink bag is sealed so that air bubbles are sandwiched between the ink bag and the ink bag. . 3. An ink bag having a gas barrier property is filled with ink and sealed, and then the ink bag is heated to 50 ° C. or higher so that air bubbles are sandwiched between the upper part and the lower part of the ink bag while the ink bag is standing up. The ink degassing method according to claim 1, wherein sealing is performed. 4. The ink degassing method according to claim 1, wherein filling and / or sealing of the ink in the ink bag is performed at a room temperature under a reduced pressure below atmospheric pressure. 5. The ink bag is filled with ink and / or sealed at 50 mmHg or less.
Ink degassing method described. 6. The ink degassing method according to claim 1, wherein filling and / or sealing of the ink in the ink bag is performed while heating the ink temperature to 50 ° C. or higher under normal pressure. . 7. The ink degassing method according to claim 3, wherein the heating temperature of the ink bag after sealing the ink bag is 50 ° C. or higher and lower than 70 ° C.