JP3603329B2 - Ink degassing method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an ink deaeration method, and more particularly, to an ink deaeration method for an inkjet recording ink.
[0002]
[Prior art]
The ink jet recording method is easily affected by bubbles and dissolved gas in the ink.In particular, the ink jet recording method using the piezo method is based on dissolved gas such as air dissolved in the ink and bubbles trapped in the container. There is a problem that injection abnormality often occurs. For this reason, proposals have been made for removing dissolved gas in the ink and preventing air bubbles from being trapped in the container.
[0003]
For example, JP-A-52-74406 and JP-A-53-61412 disclose a method of dissolving an oxygen scavenger in an aqueous ink to remove oxygen from air dissolved in the ink. Methods for reducing the amount of dissolved gas have been proposed. Japanese Patent Application Laid-Open No. Sho 62-121062 proposes a method of manufacturing an ink cartridge for an ink jet printer in which highly degassed ink is vacuum-packed under a high vacuum at the time of filling. Japanese Patent Application Laid-Open No. 2-91165 discloses that when an ink produced using a production apparatus having a heating means and a reflux means is placed in an environment of 70 ° C. for 160 hours after degassing, the amount of nitrogen generated during that time is as follows. There has been proposed a method for producing an ink jet recording ink having a step of controlling a heating means so as to be 2 to 10 ppm.
[0004]
[Problems to be solved by the invention]
In the methods described in JP-A-52-74406 and JP-A-53-61412, only oxygen can be removed by the oxygen scavenger, and the dissolved gas cannot be completely removed. Alternatively, there is a problem in that a reaction product after the oxygen scavenger is oxidized by oxygen adversely affects the stability of the ink. The method described in Japanese Patent Application Laid-Open No. Sho 62-121062 has a problem that the ink composition tends to change due to evaporation of the ink component having a low boiling point due to high degassing. The method described in Japanese Patent Application Laid-Open No. Hei 2-91165 has a problem that the heating at a high temperature of 80 ° C. or higher and the subsequent heating at 70 ° C. for 160 hours not only evaporates the low-boiling components but also easily deteriorates the ink. Was.
[0005]
The problem to be solved by the present invention is to provide an ink degassing method that effectively removes bubbles and dissolved gas in ink without causing a change in the ink composition or deterioration of the ink and without impairing the stability of the ink. It is in.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have solved the present invention.
[0007]
That is, in order to solve the above-described problems, the present invention fills an ink bag having a gas barrier property with ink, seals the ink bag, and then seals the lower portion from the top of the ink bag while holding the ink bag so as to sandwich air bubbles. An ink degassing method is provided.
[0008]
In the method of the present invention, (1) in the above-described ink deaeration method in which a portion from the top to the bottom of the ink bag is sealed so as to sandwich air bubbles while standing the ink bag, a bag thickness adjusting jig is used; (2) After filling and sealing the ink in the ink bag, the ink bag is heated to 50 ° C. or higher, and the lower portion of the ink bag is sealed from the top to the bottom while the ink bag is standing, (3) Filling and / or sealing the ink in the ink bag is performed at room temperature under reduced pressure to below atmospheric pressure. (4) At room temperature, the pressure is reduced to below atmospheric pressure, preferably 50 mmHg or less, to fill the ink bag with ink and / or Sealing, (5) Filling and / or sealing the ink in the ink bag by heating the ink at normal pressure to a temperature of 50 ° C or higher, preferably 50 ° C or higher and lower than 70 ° C, is more effective. It is possible to perform the degassing of the ink.
[0009]
Hereinafter, the configuration of the present invention will be described in detail with reference to the drawings.
[0010]
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), nylon, or polychlorinated on the outer surface. A laminate composed of two or more laminated films of a plastic material having excellent gas barrier properties such as vinyl, polyvinylidene chloride, and polyvinyl alcohol, and preferably having a metal foil or metal deposited layer of aluminum or the like between the inner and outer surfaces. Film is preferred.
[0011]
The ink b to be filled in the ink bag can be either an aqueous ink or an oil-based ink containing a low-boiling or high-boiling organic solvent as a main solvent.
[0012]
The filling c of the ink into the ink bag does not require the deaeration operation of the ink to be performed in advance, but preferably does not change the ink composition using a conventionally known deaeration means such as heating or decompression. The ink may be degassed d in advance. The heating temperature at this time is preferably 50 ° C. or more, and the reduced pressure is more preferably 50 mmHg or less.
[0013]
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 can be sucked out with a suction needle provided on the printer side. It is more preferable that the rubber stopper and the ink in the bag are separated by a plastic molded product at the outlet, since high sealing properties can be maintained when the ink cartridge is not used.
[0014]
The sealing of the ink bag a after filling the ink bag of FIG. 2 with the ink, that is, the upper seal f is performed by a sealing method such as an impulse seal or a heat seal. The sealing may be performed at normal temperature and atmospheric pressure, but is preferably performed. Is preferably performed at normal temperature and at atmospheric pressure or lower, more preferably at a vacuum g of 50 mmHg or lower. A pressure-reducing seal under heating is not always preferable because the ink tends to boil.
[0015]
Heating of the ink bag a after sealing the ink bag in FIG. 3 is performed using a constant temperature device h or the like, and the temperature is preferably 50 ° C. or more and less than 70 ° C. at normal pressure. As a result, the gas dissolved in the ink is generated as a bubble i in the ink bag. If 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 liable to become bubbles during storage, which causes ink not to be ejected. At 70 ° C. or higher, deterioration and deterioration of the ink bag become remarkable.
[0016]
Heating the ink bag after sealing the ink bag, if the heating time is short, insufficient generation of dissolved gas bubbles, cavitation due to vibration of the piezo element at a high drive frequency, long-term storage of bagged ink and hot When the ink is stored in a place, the dissolved gas remaining in the ink is bubbled to cause ejection failure. Therefore, it is preferable to perform the heating for 3 hours or more in a heating temperature range of 50 ° C. to 70 ° C. However, if the ink is heated at a high temperature for a long time, the quality of the ink itself and the quality of the bag container will be affected.
[0017]
When a highly volatile substance is contained as an ink component, it is difficult to deaerate in advance, but it is possible to deaerate without changing the ink composition by heating and secondary sealing of the ink bag after sealing the ink bag. Become.
[0018]
The so-called secondary seal shown in FIG. 4 is such that after filling, sealing and heating of the ink in the ink bag, the portion j below the upper seal i of the ink bag is immediately sandwiched with the bubble i together with the ink b while standing up the ink bag a. A secondary seal is performed to expel bubbles in the ink bag. In order to eliminate variations in the amount of bubbles expelled from the ink bag and the variation in the amount of ink in the ink bag, it is preferable to use a bag thickness adjusting jig k as shown in FIG.
[0019]
After the secondary sealing, the side l of the upper end of the bag where the air bubbles are trapped may be left attached to the bag body, but may be cut off.
[0020]
As a means to check the amount of dissolved gas and bubbles in the ink bag, air is a problem for most inks.If the dissolved gas is air, measure the amount of dissolved oxygen using a commercially available dissolved oxygen meter. However, the method of estimating the total air amount is the simplest. In the case of other gases, direct analysis with ink is also possible if the equipment can be analyzed.However, in the case of general gas, the ink is heated in a sealed system using the phenomenon of solubility reduction due to heating, and the amount of gas generated Can also be measured.
[0021]
In addition, the inkjet printer using the piezo method is very susceptible to dissolved gas and air bubbles, and particularly when continuous ejection is performed, an ink non-ejection phenomenon occurs due to the influence of the dissolved gas and air bubbles. The continuous injection test is an effective means for examining the degassing effect, and is practical.
[0022]
【Example】
Next, the present invention will be described more specifically with reference to ink examples, examples and comparative examples.
[0023]
(Ink example 1)
C. I. Solvent Black 43 8.0 parts by weight Joncryl 682 11.0 parts by weight (Styrene acrylic acid copolymer resin manufactured by Johnson Polymer Co.)
Dibutyl sebacate 1.0 part by weight Ethanol 80.0 parts by weight After sufficiently stirring and dissolving the above mixture, the solution was filtered using a 0.5 μm membrane filter without deaeration, and the mixture was filtered. The ink used in the example was obtained.
[0024]
(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 90.5 parts by weight ion-exchanged water 90.5 parts by weight After mixing and dissolving each of the above components, the remaining components are additionally dissolved, and the pore size is 0.5 μm. Filtration was performed without performing deaeration with a membrane filter to obtain an ink used in this example.
[0025]
(Example 1)
An ink bag made of a PET / aluminum / PE laminate film was filled with the ink obtained in Ink Example 1 at normal 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, hold it with a holder made of a rigid plastic material, seal the lower part from the top of the bag so that air bubbles are sandwiched, degas the ink, and fill the bag with 100 cc of ink. Got.
[0026]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo-type ink jet printer and performing continuous ejection, 30 out of 100 ink cartridges resulted in non-ejection of ink two to three times in the middle. , And the remaining 70 nozzles could be ejected to the end without any ink non-discharge.
[0027]
When the upper portion of the bag of ink in which the ink was not ejected was sucked out with a micro syringe, bubbles having a capacity of about 0.03 cc were captured.
[0028]
(Example 2)
An ink bag composed of a PET / aluminum / PE laminate film was filled with the ink of Ink Example 1 at normal temperature and normal pressure, and sealed using an impulse sealer to obtain a bag-filled ink. Next, the bag-filled ink is heated at 50 ° C. for 5 hours, and the bag is held by hand. While standing, the lower part of the bag is sealed so as to sandwich air bubbles, and the ink is degassed. A stuffed ink was obtained.
[0029]
As a result of attaching the ink cartridge containing the bagged ink in the hard case to the piezo-type ink jet printer and performing continuous ejection, 50/100 ink cartridges failed to discharge ink 2 to 5 times in the middle. , And the remaining 50 could be ejected to the end without any non-ejection of ink.
[0030]
When the upper part of the bag of ink in which the ink was not ejected was sucked out with a micro syringe, bubbles having a capacity of about 0.05 cc to 0.1 cc were captured.
[0031]
(Example 3)
In Example 2, after heating the bag-filled ink at 50 ° C. for 5 hours, instead of holding the bag by hand, hold the bag with a holder made of a rigid plastic material and seal the lower part of the bag from the top to the bottom so that air bubbles are interposed therebetween. Then, the ink was degassed to obtain a packaged ink containing 100 cc of the ink.
[0032]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo-type ink jet printer and performing continuous ejection, 10 out of 100 ink cartridges caused non-ejection of ink 2 to 5 times in the middle. , And the remaining 90 could be ejected to the end without any ink non-discharge.
[0033]
When the upper portion of the bag of ink in which the ink was not ejected was sucked out with a micro syringe, bubbles having a capacity of about 0.02 cc were captured.
[0034]
(Example 4)
An ink bag composed of a PET / aluminum / PE laminated film was filled with the ink of Ink Example 2 at room temperature and normal pressure, and sealed using a vacuum chamber type impulse sealing machine under a reduced pressure of 30 mmHg to obtain a bagged ink. . Next, the bag-filled ink is heated at 60 ° C. for 15 hours, and the bag is held by hand, and while standing, the lower part of the bag is sealed so as to sandwich bubbles, and the ink is degassed. A stuffed ink was obtained.
[0035]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo type ink jet printer and performing continuous ejection, one of the 100 ink cartridges did not eject ink once in the middle, but the ink was ejected to the end The remaining 99 ink jets could be ejected to the end without any non-ejection of ink.
[0036]
When the upper part of the bag of the ink in which the ink was not ejected was sucked out with a micro syringe, bubbles having a capacity of about 0.01 cc were captured.
[0037]
(Example 5)
An ink bag made of a PET / aluminum / PE laminate film was filled with the ink of Ink Example 2 after heating at normal pressure and 70 ° C. for 1 hour, and then sealed with an impulse sealer 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 lower part of the bag is sealed so as to sandwich air bubbles, and the ink is degassed. Ink was obtained.
[0038]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo-type inkjet printer and performing continuous ejection, the ink was not ejected 2 to 5 times in 5 out of 100 ink cartridges. , And the remaining 95 inks could be ejected to the end without any non-ejection of ink.
[0039]
When the upper portion of the bag of ink in which the ink was not ejected was sucked out with a micro syringe, bubbles having a capacity of about 0.01 cc to 0.05 cc were captured.
[0040]
(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 the bag with a holder made of a rigid plastic material, the lower portion of the bag was sealed so as to sandwich air bubbles. The ink was degassed to obtain a bagged ink containing 100 cc of the ink.
[0041]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo type inkjet printer and performing continuous ejection, all the ink cartridges out of 100 ink cartridges can be ejected to the end without ink discharge in the middle Met.
[0042]
No air bubbles were observed in the bagged ink bag.
[0043]
(Comparative Example 1)
An ink bag composed of a PET / aluminum / PE laminated film was filled with the ink of Ink Example 1 at room temperature and pressure, and sealed using an impulse sealer to obtain a bagged ink containing 100 cc of ink.
[0044]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo type ink jet printer and performing continuous ejection, all 100 ink cartridges frequently fail to eject ink halfway and cannot be ejected to the end Was.
[0045]
When the upper portion of the bag of ink in which the ink was not ejected was sucked out with a syringe, bubbles having a capacity of about 0.5 cc to 1 cc were captured.
[0046]
(Comparative Example 2)
An ink bag composed of a PET / aluminum / PE laminated film was filled with the ink of Ink Example 2 at room temperature and normal pressure, and sealed using an impulse sealer to obtain a bagged ink containing 100 cc of ink.
[0047]
As a result of mounting the ink cartridge containing the bagged ink in the hard case to the piezo type ink jet printer and performing continuous ejection, all 100 ink cartridges frequently fail to eject ink halfway and cannot be ejected to the end Was.
[0048]
When the upper portion of the bag of ink in which the ink was not ejected was sucked out with a syringe, bubbles having a capacity of about 0.5 cc to 1 cc were captured.
[0049]
【The invention's effect】
After filling and sealing the ink in the ink bag having gas barrier properties, if the ink bag is set up and sealed so that air bubbles are sandwiched from the upper part to the lower part of the ink bag, the ink can be effectively degassed. .
[0050]
The use of a bag thickness adjusting jig allows more effective degassing when sealing the lower portion of the ink bag from above while holding the ink bag so as to sandwich air bubbles.
[0051]
After filling the ink bag with the gas barrier property with the ink and sealing it, the ink bag is heated to 50 ° C. or more, and the ink bag is raised while the ink bag is sealed so that air bubbles are sandwiched from the upper part to the lower part of the ink bag. Ink can be effectively degassed.
[0052]
When the ink filling and / or sealing is performed at room temperature and the pressure is reduced to the atmospheric pressure or less to perform the degassing of the ink, more effective degassing becomes possible.
[0053]
Filling and / or sealing the ink at normal temperature, preferably at 50 mmHg or less, or while heating the ink at 50 ° C. or more at normal pressure, enables more effective deaeration.
[0054]
Heating the ink bag after sealing the ink bag is preferably performed at a temperature of 50 ° C. or more and less than 70 ° C., so that effective degassing can be performed and the influence on the ink and the ink bag can be minimized. Become.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an ink bag used in the present invention and a process of filling the ink bag with ink.
FIG. 2 is a schematic view showing a process of sealing an ink bag.
FIG. 3 is a schematic diagram showing a heating step of the 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 same.
[Explanation of symbols]
a Ink bag b Ink c Filling port d Deaeration e Ink removal port f Upper seal section g Vacuum system h Thermostat i Bubbles j Secondary seal section k Bag thickness adjustment jig l Bubble confinement section

Claims (8)

After filling the ink into an ink bag having a gas barrier property and sealing the upper portion of the ink bag by sealing , air bubbles are sandwiched between the upper portion and the lower portion of the ink bag while the ink bag is standing. A secondary seal as described above. An ink bag having a gas barrier property is filled with ink, and the ink bag is sealed with an upper seal portion f. Then, while the ink bag is standing, air bubbles are sandwiched between the lower portion and the upper portion of the ink bag by the secondary seal portion j. And a secondary seal. The ink degassing method according to claim 1 or 2, wherein a bag thickness adjusting jig is used when performing the secondary sealing. 3. The ink degassing method according to claim 1, wherein the ink bag is heated to 50 [deg.] C. or more before filling and sealing the ink bag and before performing the secondary sealing. The ink degassing method according to claim 1, wherein the filling and / or sealing of the ink in the ink bag is performed at a normal temperature while reducing the pressure to an atmospheric pressure or less. 6. The ink degassing method according to claim 5, wherein the filling and / or sealing of the ink in the ink bag is performed at 50 mmHg or less. The ink degassing method according to claim 1 or 2, wherein the filling and / or sealing of the ink in the ink bag is performed while heating the temperature of the ink to 50 ° C or more at normal pressure. The ink degassing method according to claim 4, wherein a heating temperature of the ink bag after sealing the ink bag and before performing the secondary sealing is 50C or more and less than 70C.

Images