JP2010260296A - Cleaning liquid for inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning liquid for inkjet printers which is used for an inkjet printer which uses nonaqueous inkjet ink containing pigments as inkjet ink, and is excellent in detergency (image density recoverability and recoverability of number of discharge nozzles) of cleaning liquid and in stability against ink when the cleaning liquid is mixed with the ink (preventability of precipitate generation and preventability of the mean particle size change). <P>SOLUTION: The cleaning liquid for inkjet printers which is used for the inkjet printer which uses the nonaqueous inkjet ink containing pigments as the inkjet ink has an organic solvent solution containing water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cleaning liquid for an ink jet printer, and more particularly to a cleaning liquid for an ink jet printer that is used in an ink jet printer that uses a non-aqueous ink jet ink containing a pigment as the ink jet ink.

  Inkjet printers are used in various markets, from home and office printers that print on absorbent media such as plain paper, to large format printers for signs that print on non-absorbent media.

  Among these, for sign applications, solvent ink and UV curable ink that can be printed on a water-resistant non-absorbent substrate are used because durability outdoors is required. Also, pigments are widely used as colorants from the viewpoint of image fastness, and the pigment content in the ink tends to increase in order to obtain a strong visual effect.

  An ink jet printer forms an image by ejecting ink droplets from a nozzle onto a recording material. In such an ink jet printer, it is important that stable ejection is performed, recording with a clear color tone and sufficiently high density is possible.

  Possible causes of unstable ink ejection include ink thickening near the nozzle and ink flow path, pigment aggregation, and foreign matter adhesion. Conventionally, a technique for periodically purging or sucking ink for such an ink ejection failure, a nozzle surface wiping technique (for example, see Patent Documents 1 and 2), an ink flow path cleaning technique (for example, Patent Document 3) has been reported. In these techniques, since the cleaning liquid flows into the ink container of the apparatus main body, a solvent similar to the ink-containing solvent is used in consideration of dispersion destruction and changes in ink physical properties. Organic solvents are widely used for cleaning liquids for non-aqueous inks such as solvent inks and ultraviolet curable inks (see, for example, Patent Documents 4 and 5). However, there has been a problem that such a cleaning liquid does not provide sufficient stable discharge.

JP 59-111856 A JP-A-8-1953 JP 10-337882 A JP 2004-182875 A JP 2007-253401 A

  The present invention has been made in view of the above problems, and an object of the present invention is used in an ink jet printer that uses a non-aqueous ink jet ink containing a pigment as an ink jet ink. Inkjet printer cleaning liquid with excellent discharge nozzle recovery performance and excellent ink stability (precipitation suppression and average particle size change suppression) when the cleaning liquid is mixed with ink It is to provide.

  1. An inkjet printer cleaning liquid used in an inkjet printer using a non-aqueous inkjet ink containing a pigment as the inkjet ink, wherein the inkjet printer cleaning liquid includes an organic solvent solution containing water. Cleaning liquid.

  2. 2. The inkjet printer cleaning liquid according to 1, wherein the inkjet printer cleaning liquid has a water content of 15 to 90% by mass.

  3. 2. The inkjet printer cleaning liquid according to item 1, wherein the inkjet printer cleaning liquid has a water content of 60 to 90% by mass.

  4). 4. The inkjet printer cleaning liquid according to any one of 1 to 3, wherein the inkjet printer cleaning liquid contains a water-soluble organic solvent.

  As a result of various studies, the present inventor has come up with an invention of a cleaning liquid suitable for non-aqueous ink.

  The thickening of the ink and the aggregation of the pigment can be cleaned with a cleaning liquid mainly composed of an organic solvent. On the other hand, the cause of the adhesion of foreign matter includes foreign matter in the ink flow path component, contamination of foreign matter during manufacture, and precipitation of components in the ink. To this end, measures can be taken to some extent by cleaning the parts, cleaning the flow path after assembly, installing a filter, etc. However, it is necessary to clean the ink components. However, cleaning with the organic solvent cleaning liquid described above is insufficient in cleaning, and as a result, a serious reliability problem such as unstable ejection occurs.

  In addition to pigment aggregates, the precipitates in the ink contain water-soluble impurities that cannot be cleaned with the organic solvent cleaning liquid as described above. Considering the use of a cleaning liquid containing water in an organic solvent, it has been found that the discharge stability can be improved even in a non-aqueous ink containing a pigment, and the present invention has been achieved.

  In order to dissolve the thickened ink and the aggregated pigment, the water content of the cleaning liquid of the present invention is preferably 15 to 90% by mass. In addition, the water content is more preferably 60 to 90% by mass from the viewpoint of dispersion destruction and deterioration of storage stability when a cleaning liquid (a cleaning liquid containing water) is mixed with ink (non-aqueous ink).

  In addition, the use of a water-soluble solvent further improves the detergency of water-soluble impurities.

  According to the present invention, it is used in an ink jet printer that uses a non-aqueous ink jet ink containing a pigment as an ink jet ink, and is excellent in cleaning properties (image density recoverability and ejection nozzle number recoverability) of a cleaning solution, and a cleaning solution. It is possible to provide a cleaning liquid for an ink jet printer which is excellent in ink stability (precipitation of precipitates and suppression of change in average particle size) when mixed with ink.

The figure which shows the serial system inkjet recording device for UV curable ink provided with the piezo-type inkjet nozzle. The figure which shows the inkjet recording device for solvent ink provided with the piezo-type inkjet nozzle.

  Hereinafter, although the form for implementing this invention is demonstrated, this invention is not limited to these.

  The present invention is a cleaning liquid for an ink jet printer used in an ink jet printer using a non-aqueous ink jet ink containing a pigment as an ink jet ink, wherein the cleaning liquid for an ink jet printer includes an organic solvent solution containing water. To do.

  In the present invention, in particular, the cleaning liquid for an ink jet printer has an organic solvent solution containing water, so that the cleaning liquid has excellent cleaning properties (image density recoverability and discharge nozzle number recoverability), and In addition, an ink jet printer cleaning liquid excellent in ink stability (precipitation generation suppression and average particle size change suppression) when the cleaning liquid is mixed with ink can be obtained.

  Hereinafter, the present invention will be described in detail.

《Non-aqueous inkjet ink》
In the present invention, the non-aqueous inkjet ink refers to a solvent ink or an ultraviolet curable ink.

  Solvent ink is an ink that forms an image by adhering to a base material by dissolving or swelling the base material with a volatile solvent as the main solvent, and has a solubility in soft polyvinyl chloride such as cyclohexanone. In recent years, there are a variety of solvents that use glycol ether as the main solvent to suppress odor.

  The ultraviolet curable ink is an ink that forms an image by being cured by ultraviolet rays, and includes an ink that undergoes cationic polymerization and an ink that undergoes radical polymerization.

(Pigment)
The pigment contained in the non-aqueous inkjet ink in the present invention is a conventionally known pigment, for example, an organic pigment such as an insoluble pigment or a lake pigment, and an inorganic pigment such as carbon black.

  The insoluble pigment is not particularly limited, for example, azo, azomethine, methine, diphenylmethane, triphenylmethane, quinacridone, anthraquinone, perylene, indigo, quinophthalone, isoindolinone, isoindoline, azine, oxazine, thiazine, Insoluble pigments such as dioxazine, thiazole, phthalocyanine and diketopyrrolopyrrole are preferred.

  Specific pigments that can be preferably used include the following pigments.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 168, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 222, C.I. I. Pigment red 254, C.I. I. Pigment violet 19, and the like.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 15: 3, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 130, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 213, C.I. I. Pigment yellow 214, and the like.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment green 7, and the like.

In addition to the above, when red, green, blue and intermediate colors are required, the following pigments are preferably used alone or in combination. I. Pigment Red 209, 224, 177, 194;
C. I. Pigment Orange 43;
C. I. Vat Violet 3;
C. I. Pigment Violet 19, 23, 37;
C. I. Pigment Green 36, 7;
C. I. Pigment Blue 15: 6;
Etc. are used.

  Examples of black pigments include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7, and the like.

<Inkjet printer cleaning solution>
The inkjet printer cleaning liquid of the present invention comprises an organic solvent containing water. In the present invention, the organic solvent solution containing water means an organic solvent solution containing water dissolved at 20 ° C. without separation.

(water)
Water is a central medium for the cleaning liquid of the inkjet printer of the present invention, and preferable water is pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, and distilled water for the purpose of reducing ionic impurities as much as possible. Water or ultrapure water can be used. In addition, it is preferable to use water sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like because generation of mold and bacteria can be prevented when the cleaning solution is stored for a long period of time.

  The water content of the cleaning liquid of the present invention is preferably 15 to 90% by mass from the viewpoint of dissolving the thickened ink and the aggregated pigment. Further, the water content is more preferably 60 to 90% by mass from the viewpoint of suppressing dispersion failure and storage stability deterioration when the cleaning liquid is mixed with the ink.

(Organic solvent)
As the organic solvent used in the cleaning liquid of the present invention, an organic solvent solution containing water according to the present invention, that is, an organic solvent solution that is dissolved and contained without separation of water at 20 ° C. There is no particular limitation even if it is a single solvent or a mixed solvent. For example, it can be appropriately used from a water-soluble organic solvent to other water-insoluble organic solvents. Among these, a water-soluble organic solvent is preferable from the viewpoint of detergency of water-soluble impurities.

  In the present invention, the water-soluble organic solvent according to the present invention means an organic solvent that can contain 1 g or more of water dissolved in 100 g of an organic solvent without separation at 20 ° C.

In the present invention, as a method for measuring the mass of water contained in 100 g of an organic solvent without separation at 20 ° C., the mass of water in the organic solvent 100 g is 5 g more than the amount of dissolved water. ), Stirred and mixed at 20 ° C. for 30 minutes, and allowed to stand (centrifugation may be used in combination). After removing the separated water, the organic solvent contained by dissolving water Weigh the mass W (g) of the following formula, W (g) -100 (g)
Therefore, the mass W (g) of water contained by being dissolved in 100 g of an organic solvent without being separated at 20 ° C. is determined. In this invention, when W (g) is 1 g or more, it determines with it being the water-soluble organic solvent which concerns on this invention.

  Although the example of the organic solvent used for the washing | cleaning liquid of this invention is given to the following, this invention is not limited to these.

  Glycol ethers (for example, ethylene glycol monoethyl, ethylene glycol monobutyl, diethylene glycol monobutyl, triethylene glycol monobutyl, propylene glycol monopropyl, dipropylene glycol monomethyl, tripropylene glycol monomethyl, diethylene glycol dimethyl ether, etc.); alcohols ( For example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, etc.); polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, Polypropylene glycol, butylene glycol , Hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.); amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine) , Diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.); amides (eg, formamide, N, N-dimethylformamide, N-methylacetamide, N, N- Dimethylacetamide, N, N-diethylacetamide, β-lactam, δ-lactam, ε-caprolactam, laurolactam, etc.); heterocycles For example, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, pyridine, etc.); sulfoxides (eg, dimethyl sulfoxide, etc.); esters (For example, ethyl acetate, butyl acetate, amyl acetate, isoamyl acetate, methyl isoamyl acetate, secondary hexyl acetate, 2-ethyl-butyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, benzyl acetate, propionic acid Butyl, isoamyl propionate, butyl butyrate, isobutyl butyrate, isoamyl butyrate, methyl lactate, ethyl lactate, butyl lactate, amyl lactate, isoamyl lactate, etc.); ketones (eg, acetone, methyl ethyl ketone, cyclohexanone, tilamyl keto) , Methyl-n-hexyl ketone, di-n-propyl ketone, diacetone alcohol, acetonyl acetone, isophorone, phorone, cyclohexanone, methylcyclohexanone, acetophenone, etc .; lactones (for example, lactones having 3 to 6 carbon atoms) Γ-butyrolactone, α-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-laurolactone, δ-valerolactone, hexanolactone, etc .; ethers (eg, dioxane, morpholine) Aromatic hydrocarbons (eg, toluene, benzyl alcohol, etc.); aliphatic hydrocarbons (eg, cyclohexane, 1,2-dichloroethane, nitroethane, etc.); and the like.

  Moreover, you may add surfactant and an antifoamer to the washing | cleaning liquid of this invention. By adding the surfactant to the cleaning liquid, the surface energy of the cleaning liquid can be adjusted, and wettability with respect to the ink jet printer can be improved. Moreover, it is possible to prevent bubbles from being generated in the cleaning liquid by adding an antifoaming agent to the cleaning liquid.

<Inkjet printer cleaning method>
Next, a method for cleaning the ink jet printer will be described.

  The inkjet printer or some parts are cleaned using the cleaning liquid of the present invention. As the cleaning method, the cleaning liquid of the present invention is circulated in the ink path of the ink jet printer, the cloth wetted with the cleaning liquid of the present invention or the ink jet blade is used to wipe the ink jet printer or its components, and the cleaning liquid of the present invention is used for the ink jet printer or the same. A method of immersing in a component, a method of applying an cleaning agent of the present invention to an inkjet printer or its component, and then contacting an absorbent with the inkjet printer or its member, and sucking the cleaning solution with the absorbent, a cleaning solution of the present invention as an inkjet printer or its component After the coating, there is a method of removing the cleaning liquid by performing air suction, air supply, etc. on the ink jet printer or its components. In particular, circulation to the ink path is effective. In order to increase the cleaning effect in ink circulation, it is preferable to increase the temperature of the cleaning liquid and the supply pressure rather than conditions such as increasing the number of circulations, ink temperature at the time of printing, and supply pressure. The temperature at this time is preferably 40 to 80 ° C.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. Unless otherwise specified, “part” or “%” in the examples represents “part by mass” or “mass%”.

Example 1
[Preparation of cleaning solution]
Cleaning liquids 101 to 123, 201 to 224, and 301 to 324 were prepared with the compositions shown in Table 1, Table 2, and Table 3. Each cleaning solution was sufficiently stirred and then filtered using a membrane filter having a pore size of 1 μm to prepare the cleaning solutions shown in Table 1, Table 2, and Table 3.

[Preparation of solvent ink, UV curable radical ink, and UV curable cationic ink]
<< Preparation of solvent ink >>
<Preparation of dispersion a>
(Preparation of yellow pigment dispersion a)
Pigment Yellow 150 (manufactured by LANXESS, E4GN-GT CH20015) 12 parts Solspers 24000 (made by IC Japan) 5 parts N-methyl-2-pyrrolidone 3 parts diethylene glycol diethyl ether 82 parts After putting in a glass bottle together with 200 g of 0.3 mm zirconia beads and sealing with a paint shaker for 4 hours, the zirconia beads were removed to prepare a yellow pigment dispersion.

(Preparation of magenta pigment dispersion a)
A magenta pigment dispersion a was prepared in the same manner as in the preparation of the yellow pigment dispersion a, except that Pigment Red 122 (CFR-321 manufactured by Dainichi Seika Co., Ltd.) was used instead of Pigment Yellow 150.

(Preparation of cyan pigment dispersion a)
In the preparation of the yellow pigment dispersion a, a cyan pigment dispersion a was prepared in the same manner except that Pigment Blue 15: 4 (Blue No. 32 manufactured by Dainichi Seika Co., Ltd.) was used instead of Pigment Yellow 150. did.

(Preparation of black pigment dispersion a)
In the preparation of the yellow pigment dispersion a, a black pigment dispersion a was prepared in the same manner except that Pigment Black 7 (# 52, manufactured by Mitsubishi Chemical Corporation) was used instead of Pigment Yellow 150.

<Preparation of ink a>
(Preparation of yellow ink a)
Dimethyl sulfoxide 1 part Diethylene glycol diethyl ether 69 parts Ethylene glycol diacetate 20 parts Vinyl chloride-vinyl acetate copolymer (VYHD, manufactured by Dow Chemicals) 10 parts were mixed, and after confirming that they were sufficiently dissolved, this mixing 50 parts of the solution was added little by little to 50 parts of the yellow pigment dispersion a prepared above while stirring. After stirring for 15 minutes, the mixture was filtered with a PP3 μm disk filter manufactured by Loki Techno Co. to prepare yellow ink a.

(Preparation of magenta ink a)
Magenta ink a was prepared in the same manner as in the preparation of yellow ink a, except that magenta pigment dispersion liquid a was used instead of yellow pigment dispersion liquid a.

(Preparation of cyan ink a)
Cyan ink a was prepared in the same manner as in the preparation of yellow ink a, except that cyan pigment dispersion liquid a was used instead of yellow pigment dispersion liquid a.

(Preparation of black ink a)
A black ink a was prepared in the same manner as in the preparation of the yellow ink a, except that the black pigment dispersion liquid a was used instead of the yellow pigment dispersion liquid a.

<< Preparation of UV curable radical ink >>
<Preparation of dispersion>
(Preparation of yellow pigment dispersion b)
Each of the following compounds was placed in a stainless beaker and dissolved by stirring and heating for 1 hour while heating on a hot plate at 65 ° C.

PB821 (Dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.) 9 parts Tetraethylene glycol diacrylate 71 parts After cooling to room temperature, add 20 parts of Pigment Yellow 150 to this and put it in a glass bottle with 200 g of zirconia beads having a diameter of 0.3 mm and plug tightly. After the dispersion treatment for 4 hours with a paint shaker, the zirconia beads were removed to prepare a yellow pigment dispersion b.

(Preparation of magenta pigment dispersion b)
A magenta pigment dispersion b was similarly prepared except that Pigment Red 122 was used instead of Pigment Yellow 150 in the preparation of the yellow pigment dispersion b.

(Preparation of cyan pigment dispersion b)
A magenta pigment dispersion b was prepared in the same manner as in the preparation of the yellow pigment dispersion b, except that Pigment Yellow 15: 4 was used instead of the Pigment Yellow 150.

(Preparation of black pigment dispersion b)
A magenta pigment dispersion b was prepared in the same manner as in the preparation of the yellow pigment dispersion b except that Pigment Black 7 was used instead of the pigment Yellow 150.

<Preparation of ink>
(Preparation of yellow ink b)
Lauryl acrylate (monofunctional) 15.0 parts Tetraethylene glycol diacrylate (bifunctional) 42.5 parts Trimethylolpropane triacrylate (trifunctional) 20.0 parts Irgacure 184 (manufactured by Ciba Japan) 2.5 parts Irgacure 907 (Ciba Japan) 2.5 parts

Were mixed and the solution was added to 17.5 parts of the yellow pigment dispersion b prepared above while stirring, stirred for 15 minutes, and then a PP3 μm disc manufactured by Loki Techno Co., Ltd. Filtration through a filter prepared yellow ink b.

(Preparation of magenta ink b)
A magenta ink b was prepared in the same manner as in the preparation of the yellow ink b except that the magenta pigment dispersion liquid b was used instead of the yellow pigment dispersion liquid b.

(Preparation of cyan ink b)
Cyan ink b was prepared in the same manner as in the preparation of yellow ink b, except that cyan pigment dispersion b was used instead of yellow pigment dispersion b.

(Preparation of black ink b)
A black ink b was prepared in the same manner as in the preparation of the yellow ink b except that the black pigment dispersion liquid b was used instead of the yellow pigment dispersion liquid b.

<< Preparation of UV curable cationic ink >>
<Preparation of dispersion>
(Preparation of yellow pigment dispersion c)
Each of the following compounds was placed in a stainless beaker and dissolved by stirring and heating for 1 hour while heating on a hot plate at 65 ° C.

PB821 (dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.) 9 parts OXT-221 (Oxetane compound manufactured by Toagosei Co., Ltd.) 71 parts After cooling to room temperature, 20 parts of Pigment Yellow 180 (E4GN-GT manufactured by Dainichi Seika Co., Ltd.) is added. Then, 200 g of zirconia beads having a diameter of 0.3 mm were put in a glass bottle and sealed, and after a dispersion treatment for 4 hours with a paint shaker, the zirconia beads were removed to prepare a yellow pigment dispersion c.

[Preparation of magenta pigment dispersion c]
A magenta pigment dispersion c was prepared in the same manner as in the preparation of the yellow pigment dispersion c, except that Pigment Red 122 was used instead of Pigment Yellow 180.

(Preparation of cyan pigment dispersion c)
A cyan pigment dispersion c was prepared in the same manner as in the preparation of the yellow pigment dispersion c except that Pigment Yellow 15: 4 was used instead of the pigment Yellow 180.

(Preparation of black pigment dispersion c)
In the preparation of the yellow pigment dispersion c, a black pigment dispersion c was prepared in the same manner except that Pigment Black 7 was used instead of Pigment Yellow 180.

<Preparation of ink>
(Preparation of yellow ink c)
Oxetane OXT-221 (Oxetane compound manufactured by Toagosei Co., Ltd.) 47.45 parts Oxetane OXT-212 (Oxetane compound manufactured by Toagosei Co., Ltd.) 5 parts Oxetane OXT-101 (Oxetane compound manufactured by Toagosei Co., Ltd.) 5 parts Alicyclic epoxy compound 20 Part Photoacid generator 2.5 parts Polymerization inhibitor (triisopropanol) 0.1 part

Were mixed and added to 20 parts of the yellow pigment dispersion c prepared above while stirring, and stirred for 15 minutes, and then with a PP3 μm disk filter manufactured by Loki Techno Co., Ltd. Filtration was performed to prepare yellow ink c.

(Preparation of magenta ink c)
A magenta ink c was prepared in the same manner as in the preparation of the yellow ink c except that the magenta pigment dispersion c was used instead of the yellow pigment dispersion c.

(Preparation of cyan ink c)
Cyan ink c was prepared in the same manner as in the preparation of yellow ink c, except that cyan pigment dispersion liquid c was used instead of yellow pigment dispersion liquid c.

(Preparation of black ink c)
A black ink c was prepared in the same manner as in the preparation of the yellow ink c except that the black pigment dispersion liquid c was used instead of the yellow pigment dispersion liquid c.

[Inkjet printer]
<< Inkjet printer using solvent ink >>
Each ink prepared above was loaded into an ink jet recording apparatus-1 having the structure shown in FIG. 2 provided with a piezo ink jet nozzle, and image formation was performed.

  In the recording apparatus, the recording medium 2 is transported along the transport direction B as each transport roller 7 rotates. An image recording unit (carriage) 4 for recording an image on the recording surface of the recording medium 2 is installed above the platen 6 inside the housing. The image recording unit 4 is arranged in a direction A perpendicular to the conveyance direction B. Reciprocate along.

  The head portion is heated according to the viscosity of each ink, and multi-size dots having a droplet amount of 2 to 15 pl are set to a resolution of 720 × 720 dpi (dpi represents the number of dots per 2.54 cm). It was driven so that it could be discharged, and ink was continuously discharged.

  The recording material was heated to 40 ° C. by a surface heater.

  The inkjet image was formed by printing in an environment of 25 ° C. and 50% RH according to the above method.

<< Inkjet printer using UV curable ink >>
Each of the inks prepared above was loaded into a serial inkjet recording apparatus-2 having the configuration shown in FIG. 1 having a piezo inkjet nozzle, and image formation was performed.

In the recording apparatus, the recording medium 2 is transported along the transport direction B as each transport roller 7 rotates. An image recording unit (carriage) 4 for recording an image on the recording surface of the recording medium 2 is installed above the platen 6 inside the housing. The image recording unit 4 is arranged in a direction A perpendicular to the conveyance direction B. Reciprocate along. The both ends in the scanning direction A, and irradiated with ultraviolet light of 300 mJ / cm ² in the ink landed on the recording medium 2, the light source to cure instantly (less than 0.5 seconds after landing) is installed, a reciprocating movement of the carriage Can be moved.

  The head portion is heated in accordance with the viscosity of each ink, and multi-sized dots having a droplet amount of 2 to 15 pl can be ejected at a resolution of 720 × 720 dpi (dpi represents the number of dots per 2.54 cm). The ink was continuously discharged.

  The recording material was heated to 40 ° C. by a surface heater.

  The inkjet image was formed by printing in an environment of 25 ° C. and 50% RH according to the above method.

[Evaluation methods]
<Detergency of cleaning liquid>
The detergency of the cleaning liquid is evaluated by the following image density recoverability and discharge nozzle number recoverability.

<Image density recovery>
These inks were mounted on an ink jet recording apparatus, and a solid image of 10 cm × 10 cm was recorded on JT5929PM (manufactured by Mactac) which is a recording medium made of polyvinyl chloride. Thereafter, the system was operated for 12 hours / day for 30 days.

  Thereafter, the ink flow path was washed using 10 ml of the washing liquid. After washing, the ink was refilled, and a solid image was printed at 10 cm × 10 cm on a recording medium JT5929PM (manufactured by Mactac).

The image density was measured using X-Rite 900 (manufactured by Nihon Hakusho Kaisha Co., Ltd.), and the image density ratio after washing was calculated as a percentage when the image density before continuous injection was taken as 100%. Based on this, the image density recovery was evaluated. The better the image density recoverability, the better the washability of the cleaning liquid.
A: Concentration ratio 91-100%
○: Concentration ratio 81-90%
Δ: Concentration ratio 71 to 80%
×: Density ratio 70% or less
At the time of measuring <image density recovery>, the number of ink droplet ejection nozzles during image printing is measured by observing with a microscope (magnification: 200 times), and the number of ink droplet ejection nozzles during image printing after washing. / The percentage of the number of ink droplet ejection nozzles at the time of image printing before continuous ejection was determined, and the recoverability of the number of ejection nozzles was evaluated based on the following evaluation criteria. The more the discharge nozzle number recoverability, the better the cleaning performance of the cleaning liquid.
: Discharge nozzle ratio 91-100%
○: Ejection nozzle ratio 81-90%
Δ: Discharge nozzle ratio 71 to 80%
×: Discharge nozzle ratio 70% or less << Stability at the time of cleaning liquid-ink mixing >>
Regarding the stability against ink when the cleaning liquid is mixed with the ink, the stability during mixing of the cleaning liquid and ink is evaluated by the following suppression of precipitate generation and suppression of change in average particle diameter.

<Precipitation generation suppression>
Mix 5 ml each of ink and cleaning liquid, put them in a glass bottle and seal them, and visually check for the occurrence of precipitates.

<Inhibition of average particle size change>
After mixing 5 ml each of ink and cleaning liquid and carrying out the promotion treatment of storage at 70 ° C. for 1 week in a light-shielding container, the average particle size value is obtained as follows, and the average particle size value of the sample before storage is From the difference, the average particle size change was determined, and the average particle size change inhibitory property was evaluated based on the following evaluation criteria. The better the average particle size change suppression, the better the storage stability when mixing the cleaning liquid with the ink.

The average particle size value was measured with a photon correlation method Zetasizer 1000HS manufactured by Malvern after dilution to about 0.5% by mass in terms of pigment concentration.
○: Particle size change less than 50 nm Δ: Particle size change from 50 nm to less than 100 ×: Particle size change of 100 nm or more The results are shown in Tables 1 to 3.

  From Table 1, Table 2, and Table 3, in the case of the present invention, as a cleaning liquid for an inkjet printer used in an inkjet printer using a non-aqueous inkjet ink containing a pigment, the cleaning performance of the cleaning liquid (image density recoverability, and It can be seen that the discharge nozzle number recoverability is excellent, and the stability against ink when the cleaning liquid is mixed with ink (precipitation suppression of precipitates and average particle size change suppression) is excellent.

  Moreover, it is found that the water content of the cleaning liquid for an ink jet printer is preferably 15 to 90% by mass, more preferably 60 to 90% by mass, and particularly preferably 70% by mass.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Recording medium 3 Recording head 3Y, 3M, 3C, 3K Recording head 4 Carriage 5 Guide member 6 Platen 7 Recording medium conveyance apparatus N Nozzle

Claims (4)

An inkjet printer cleaning liquid used in an inkjet printer using a non-aqueous inkjet ink containing a pigment as the inkjet ink, wherein the inkjet printer cleaning liquid includes an organic solvent solution containing water. Cleaning liquid. The cleaning liquid for an ink jet printer according to claim 1, wherein the water content of the cleaning liquid for the ink jet printer is 15 to 90% by mass. 2. The cleaning liquid for an ink jet printer according to claim 1, wherein the water content of the cleaning liquid for the ink jet printer is 60 to 90% by mass. The inkjet printer cleaning liquid according to claim 1, wherein the inkjet printer cleaning liquid contains a water-soluble organic solvent.

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