JPS5889667A - Fluid ink for printer - Google Patents

Abstract

PURPOSE:The titled ink, prepared by adding a chelating agent to an ink, having improved stability and storability for a long term, and good storability even at high temperatures and in glass heads, scarcely generating impurities, and suitable for ink jet recording apparatuses, etc. CONSTITUTION:A fluid ink prepared by adding (ii) 0.01-0.5pts.wt. chelating agent, e.g. ethylenediaminetetraacetic acid, to (i) an ink of 12-13.5pH at 20 deg.C, and adding (B) a pH adjustor, e.g. potassium hydroxide, (C) 10pts.wt. or less dye, (D) 5-45pts.wt. wetting agent, e.g. ethylene glycol, and (E) water to (A) the resultant ink. USE:Usable for all the printers using a fluid ink.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid ink for printers based on inkjet recording devices, and is concerned with the long-term stability of 'liK ink,
This invention relates to a water-based ink for inkjet recording with improved storage stability.

The field of inkjet recording sickle device is 50-1507m.
Desired printing is made possible by means of generating ink droplets of minute diameter and means of flying the droplets to a predetermined position on the recording paper. The droplet is a pressurized ink of 50~
An electrostatic deflection type inkjet system, in which the droplets are ejected from a fine nozzle orifice with a diameter of 100 mm, and the droplets are charged and then fly to a predetermined position on the recording paper by operating an electric field. There is a drop-on demand type inkjet method that generates droplets only where needed from multiple nozzles and flies them directly onto the recording paper. Since both are inkjet methods, they have the following problems in handling liquid ink.

1) The ink dries in the nozzle orifice, which has a fine diameter of sO to 150 pm, and the nozzle orifice becomes clogged due to an increase in the viscosity of the ink at the nozzle orifice, or due to precipitation of dye, etc.

2) It takes time for the 113 ink particles to dry after directly adhering to the recording paper, that is, printing drying time.

5) Since the ink cannot be pressurized in the ink pressurizing chamber of the recording head due to air bubbles being mixed in or generated in the ink distribution path, minute droplets of ink are generated from the nozzle orifice and the ink is not filled.

4) The dot circularity and dot contrast of the ink droplets adhering to the recording paper are insufficient.

In view of these problems, the requirements for an inkjet recording ink are: a) the ink should not cause clogging in the nozzle orifice of the recording head;

b) When the ink is transferred to the writing paper, it dries quickly.

C) The ink does not contain components that generate gas by themselves.

d) The ink does not deteriorate over a long period of time and has good storage properties.

e) The ink does not corrode materials in contact with the ink.

f) When the density of the ink is high and it is transferred to paper, the circularity and contrast of the dots are clear.

etc. can be mentioned. As an ink that satisfies these conditions a) to f), the ink ('
? In other words, there is an ink in which the ink droplet size is adjusted to 12 to 1 to 5 at 20°C.

The wrinkle ink has a very high pH value of 12 to 155, dissolves the sizing agent and surface treatment agent used to improve the water resistance of the paper, and quickly penetrates into the pulp. Therefore, the ink dries quickly while maintaining the circularity and contrast of the dots, and does not stain the paper or fingers after printing.However, the ink has a PH Due to the high value, when the ink was stored for a long period of time, insoluble matter precipitated, resulting in insufficient long-term stability and loading properties of the ink.

In addition, the ink sometimes reacted with the glass in the printing bed (made of white glass), causing insoluble matter to be scrutinized.

The present invention eliminates such drawbacks, SL) to f)
It is an object of the present invention to provide an ink for inkjet 1 brass that satisfies the following conditions, is stable over a long period of time, has a high shelf life, and does not easily generate insoluble matter. 'When stored for a long time, the causes of precipitation such as insoluble matter are 1) Reaction products between dye and strong alkali 2) Preservation bottles (
It is thought that reaction products between ions eluted from glass and dyes may be produced, and the present inventor has determined 2) K, and in order to mask the metals eluted from glass, the inventors added a chelating reagent to the ink for a long period of time. I saved it and got good results.

As ink, dye, humectant glycerin, pH 1
．． Inkum (L
1wt ethylenecyaminetetraacetic acid disodium (ED)
Ink 1 containing T-munisodium) was added at room temperature and 4
When stored in a 5c environment for one month, inkum precipitated in both environments, especially in large amounts at 65°C.

On the other hand, regarding ink In, no precipitation occurred in either ring jlHc, and the ink was stable.

It is thought that there are many metal ions in the ink in addition to the metal ions eluted from the glass, and the metal ions M
is ID Tem Aeon! It is thought that no insoluble matter is generated because a chelate compound is formed with 4° and masks the metal ions.

For example, when ν・ and Oa are eluted from glass or contained in dyes, they are chelated with EDT and stabilized in water in the form of y・ and OaY, and other than ν・ and Oa. Preventing the impact on .

Furthermore, the ink containing 1 chelating reagent showed excellent rolling stability even at high temperatures, making it possible to extend the storage range of the ink.

Chelating reagents include, in addition to the above-mentioned ID-muni-sodium, $'C, ICD-muni-sodium, and tetrasodium;
tD'rm can also be used because it can be dissolved as is. Other examples include trans-1,2-shift-tetra-hexane-tetraacetic acid (0yDT), glycol ether cyagine-tetraacetic acid (GIDT), diethylenetriaminepenta-acetic acid (D! fam), triethylene-tetra-enhexane (TT11), ), nitori-tetravinegar 12 (Nτm), tetraethylenepentadenhebutavinegar @ ('rP11m), M-(cohydroxyethyl)-ethylenecyamine-M, M',
N'-triacetic acid (IDTA O!II), ethylenecyamine-N.

M, N', M'-? ,,) 5-propionic acid (I
DTP) There is a cape.

The content of the chelating reagent in the ink is that the amount of metal ions is very small! The amount sufficient for skinning is sufficient, and it is sufficient to contain a5 parts by weight based on the total amount of ink. In addition, if the ink is contained in a large amount, clogging is likely to occur when the ink dries in the nozzle orifice.

The ink of the present invention is characterized by containing one chelating reagent in the ink of I'H12-1&5, and the composition consists of a KPHIII agent, a dye, a wetting agent, and water in addition to the chelating reagent.

The pH adjuster is used to make the ink permeate into the writing paper more quickly and dry quickly when the Pli of the ink is adjusted to 12 to 1&5. Therefore, basic substances are preferable, and stable strong basic substances with excellent solubility in water and wetting agents are suitable, and alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and lithium hydroxide are suitable. There is. In addition, alkaline earth metal hydroxides, alkali metal carbonates, ammonia, amines, etc. can also be used.

The dye is preferably a water-soluble direct dye or a disperse dye in order to first improve the water resistance and light resistance of printed matter.
Also, the greater the solubility and dispersion in water and wetting agents, the more likely it is that the nozzle orifice will become clogged due to dye precipitation.
Therefore, dyes with high solubility and dispersion in water and II#lI agents are preferred.

For example, Kayakv Dir@ot Dtep B1
aakX Mu-Kayaku Dir@ot 8p@oi
al BlaakmXM.

Kayaset Beak 00? Kayaset
Blackolo, Kayasst Blaak 02
1. Kayas@tBlaok 922. Kayaru
s 8upro 8oarlstBNL, Kayaka
lan #oarlstGL, Kayas*tRed
O04, Kayaset R@1 008. Kay
art1m Turguois* Blue GL (all exhibited at Nippon Kakenten), etc.The amount of dye added is preferably 10 parts by weight or less, since if it exceeds 10 parts by weight, clogging of the nozzle orifice tends to occur.

Wetting agents lower the overall vapor pressure of the ink, making the ink ±.

In addition to slowing down the evaporation of water, dyes and basic substances are also dissolved, thereby preventing clogging of the nozzle orifice. Therefore, first of all, it is preferable to use wetting agents that have good solubility in water, have water absorption properties, and also have high dye yield and basic substance solubility, such as alkyl ether derivatives of aliphatic polyhydric alcohols, Acetate derivatives of alcohols are excellent. The A-bodies include ethylene glycol, diethylene glycol, triethylene glycol, tetrapyrene glycol, polyethylene glycol, polyhydric alcohols of Cape Grishichisun, ethylene glycol monomethyl ether, sweat terenda glycol monoethyl ether, and diethylene glycol monoethyl ether. , alkyl ether derivatives of polyhydric alpools such as diethylene glycol motuptyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, glycer diacetate, There are acetate conductors of polyhydric alcohols such as glycer diacetate. It is also possible to use mixtures of the above-mentioned polyhydric alcohols, alkyl ether derivatives of polyhydric alcohols, and acetate derivatives of polyhydric alcohols.

As for the amount of wetting agent added, if it is too small, clogging in the nozzle orifice is likely to occur, and if it is too large, the viscosity of the entire ink increases, which is not preferable. This is because as the ink viscosity increases, the response frequency of the inkjet recording head decreases and the driving voltage decreases.
This is because it has been confirmed by the present invention.

Therefore, it is preferable to add 5 to 45 parts by weight of the agent, and the viscosity is also 15 to 1? It is possible to adjust to a range of 11 centipoise.

Furthermore, it is also possible to add hydroxyalkyl-2-pyrrolidones represented by ou and y-alkyl-2-pyrrolidones represented by ou to the present invention, and these components are added in an amount of 1 to 14 parts by weight. It has been recognized that the effect of clogging the nozzle orifice and stopping spinning is improved when used in combination with a humectant.

In addition, for long-term ink storage, known anti-mold agents such as dioxin, sodium tehyde, and Houcide LX-H (anti-mold agent manufactured by Hokuko Chemical Co., Ltd.) may be used to suppress the growth of bacteria and mold. However, in the case of the ink of the present invention,
Since the PIE value of the ink was high, no bacteria were observed even if no antifungal agent was added.

Note that the ink of the present invention can also be used in printers using all fluid inks, and is not limited to ink for inkjet printers.

As described above, according to the present invention, not only can the requirements a) to f) above be satisfied, but the ink has excellent long-term stability and storage stability, and also has excellent stability and storage stability even in high-temperature environments. It also has a good shelf life even in glass heads, and its effects are very significant.

The present invention will be explained below by giving Examples, but these Examples explain the present invention more specifically, and the embodiments are not limited thereto.

Example 1 2t capacity 41K equipped with stirrer and reflux device.

Add distilled water and 1 sot of glycerin, stir, and add 1 F of sodium Davidtetraacetate.

10f of potassium hydroxide was added. Gradually heat the container to confirm that the additive has dissolved, then add 1 ton of sodium ethylenediaminetetraacetate, and when it is completely dissolved, add K.
ayaku nir@ot DeepB'1aak! 20 tons of aluminum were gradually added. Stirring was continued for 6 hours while keeping the temperature inside the container constant at 60C. After cooling to room temperature, it was left open for about 24 hours, and then filtered through a 1 μ thick bore membrane filter. The obtained ink is as follows.

(Composition) The viscosity of the obtained ink was 20°C'Q 1.8 c p%
The surface tension was 54 d7ne10n at 20C, and the P H was 12.7 at 20C.

When this ink was filled in our prototype multi-nozzle head (nozzle orifice diameter: 40 Pm) and jet printing was performed, a stamped brass with clear black color and high printing quality was obtained. The drying time of the ink on the paper after printing was approximately 5 seconds, indicating sufficient quick-drying properties for use.

In addition, when an ink made of borosilicate glass having the above composition was put into the ink and left in a 65C environment for 5 tons, no precipitation of insoluble matters was observed in the ink.

Example 2 An ink having the following composition was prepared by the method described in Example 1.

(Composition) The viscosity of the obtained ink was 20t! 2a, p,, surface tension is 20C and 46 dyne/am%PH H value is 2
IL7 at 0°C.

Example 5 An ink having the following composition was prepared by the method described in Example 1.

(Composition) The obtained ink has a viscosity of t, 8c, p at 20C, and a surface tension of 55 dyne/am, P at 20C! I is 2o
It was 114 in e.

Example 4 An ink having the following composition was prepared by the method described in Example 1.

(Composition) The obtained ink had a viscosity of 1.8 aep at 20C, a surface tension of 61 dyne/am at 200C, and a PH value of 125 at 20C.

The inks of Examples 1 to 4 were applied to our prototype multi-nozzle head (
When the nozzle orifice diameter was 40 μm) and jet printing was performed, the print quality was high and the print quality was high, and it dried in about 5 seconds after printing.

For clogging of the nozzle orifice, leave the nozzle orifice open to the atmosphere for 10 minutes after jet printing for 1 hour.
After 0 hours, re-jetting was carried out.→(, The ink of this example was successfully re-jetted without any clogging. Also, from borosilicate glass.

When the inks of Examples 1 to 4 were placed in a container, sealed tightly, and left at room temperature and 45°C for an evening, the inks were always stable and did not precipitate insoluble matter, and were very stable. The shelf life was also high and good.

Furthermore, our prototype multi-nozzle head (made of white glass)
Even when the inks of Examples 1 to 4 were filled so as not to evaporate and left in an environment of room temperature and 65° C. for a period of KA, no insoluble matter was generated in the head, and good results were obtained.

that's all Applicant: Shinshu Seiki Co., Ltd. Representative Patent Attorney Mogami

Claims (1)

[Scope of Claims] 1) A fluid ink for a printer, characterized in that the ink has a pH value in the range of 12 to 1&5 at 20 tl:l and contains a chelating reagent. . 2) The fluid ink for printers according to item 1 of the patent, wherein the chelating reagent is ethylenedianetetraacetic acid and/or an alkali salt thereof.