JP2021084230A - Inkjet printing device, inkjet printing method, and glossiness control method of printed image - Google Patents

Abstract

To provide an inkjet printing device which can cope with gloss control of both low gloss and high gloss, and can suppress occurrence of color unevenness of a printed image even with high productivity.SOLUTION: An inkjet printing device has an ink storage part for storing ink, a discharge head for discharging the ink to form a printed layer, and heating means for heating a printed matter. The ink has clear ink containing a resin and water and color ink containing a resin, a pigment and water. The color ink contains cyan ink, a mass ratio (P/R) of a content P of a cyan pigment to a content R of a resin in the cyan ink satisfies 0.08 or more and 0.20 or less. The inkjet printing device is a printing device for printing the clear ink onto the color ink and has a low gloss printing mode that is a printing mode for imparting low gloss and a high gloss printing mode that is a printing mode for imparting high gloss. When a temperature of the printed matter in the low gloss printing region for performing printing in the low gloss printing mode when the clear ink is attached onto the color ink is represented by Tlow(°C), and a temperature of the printed matter in the high gloss printing region for performing printing in the high gloss printing mode when the clear ink is attached onto the color ink is represented by Thigh(°C), the heating means heats the printed matter so as to satisfy a following expression Tlow>Thigh.SELECTED DRAWING: None

Description

The present invention relates to an inkjet printing apparatus, an inkjet printing method, and a method for controlling glossiness of a printed image.

In order to improve durability such as light resistance, water resistance, and abrasion resistance in industrial applications such as advertisements and signboards, and packaging materials for foods, beverages, daily necessities, etc., for example, impermeable recording media such as plastic films are used. Various inks used for such impermeable recording media have been developed.

As such inks, for example, solvent-based inks using an organic solvent as a solvent, ultraviolet (UV) curable inks containing a polymerizable monomer as a main component, and the like are widely used. However, the solvent-based ink is concerned about the influence on the environment due to the evaporation of the organic solvent. In the ultraviolet curable ink, the choice of polymerizable monomer used may be limited from the viewpoint of safety.
Therefore, in recent years, many ink sets containing water-based inks, which have a low environmental load and can be directly recorded on a non-penetrating recording medium, have been proposed.

On the other hand, various inkjet recording devices having a gloss control function have been developed.
When the ink is landed on a non-penetrating recording medium as described above to form a film, the glossiness of the appearance can be controlled by the degree of unevenness of the ink film, giving a high-class feeling or giving a matte texture. It is possible to give it.

For example, a liquid injection device has been proposed in which the degree of film formation on the surface of the ink droplet is controlled by heating at a film formation control temperature corresponding to the minimum film formation temperature at which film formation on the surface of the ink droplet starts. For example, see Patent Document 1).

Further, two types of ink layers having different minimum film forming temperatures are formed, which are heated and pressurized using the first fixing means, then heated and pressurized using the second fixing means, cooled, and then peeled off. An inkjet recording method has been proposed (see, for example, Patent Document 2). High gloss and low gloss are controlled by keeping the minimum film forming temperature of the two types of ink layers and the temperatures at the time of heating and pressurization in the two types of fixing means in a specific relationship.

In addition, it has color ink and clear ink that are cured by irradiation with active light, and when the ink on the recording medium is irradiated with ultraviolet rays to temporarily cure the ink, the amount of irradiation light is set for each irradiated portion to create a matte texture. And an inkjet recording device that forms a glossy texture has been proposed (see, for example, Patent Document 3).

On the other hand, in inkjet recording devices, there is a strong market demand for improving productivity. In wide-width inkjet printing equipment used in the sine graphic field, the multi-pass method in which the head scans in the media width direction (main scanning direction) and the media is conveyed perpendicular to the head scanning direction (secondary scanning direction) is used. It is common. In order to improve productivity in such a multi-pass method, in order to increase the printing area in one pass, a plurality of nozzle rows in which a plurality of nozzle holes for ejecting ink are arranged in the sub-scanning direction orthogonal to the main scanning direction are arranged. Although it is effective to use a head equipped with the above, there is a side effect that ink droplets are likely to be misaligned, and it is an issue to achieve both productivity and image quality.

It contains a specific pigment type, and the pigment content in cyan ink, magenta ink, and yellow ink is 1.5 to 6% by weight, respectively, and the pigment content ratio is cyan: magenta: yellow = 1: 1 to 1. By setting the ratio to 2: 1 to 3, it is possible to obtain excellent printing suitability on a substrate having low water absorption such as coated paper, art paper, and vinyl chloride sheet, to obtain a high quality image, and to have ejection stability. Ink for inkjet excellent in the above has been proposed (see, for example, Patent Document 4).

An object of the present invention is to provide an inkjet printing apparatus capable of supporting both low gloss and high gloss control and suppressing the occurrence of color unevenness in a printed image even with high productivity.

The inkjet printing apparatus of the present invention as a means for solving the above-mentioned problems includes an ink accommodating portion for accommodating ink, an ejection head for ejecting ink to form a printing layer, and a heating means for heating an object to be printed. The ink has a clear ink containing resin and water and a color ink containing resin, pigment, and water, and the color ink contains cyan ink. The mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less, and the inkjet printing apparatus prints clear ink on the color ink. The printing apparatus has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. _{The temperature of the object} to be printed in the low-gloss printing area to be printed in the low-gloss printing mode when adhering to is set to Low (° C.), and printing is performed in the high-gloss printing mode when the clear ink is adhered to the color ink. Assuming that the temperature of the object to be printed in the high-gloss printing area is T _high (° C.), heating is performed so as to satisfy the _{following equation, T low} > T _high.

According to the present invention, it is possible to provide an inkjet printing apparatus capable of supporting both low gloss and high gloss control and suppressing the occurrence of color unevenness in a printed image even with high productivity.

FIG. 1 is a diagram showing an example of an image forming apparatus that implements the image forming method of the present invention. FIG. 2 is a perspective explanatory view showing an example of the main tank of the image forming apparatus of FIG.

(Inkjet printing device and inkjet printing method)
One aspect of the inkjet printing apparatus of the present invention is an inkjet printing apparatus having an ink accommodating portion for accommodating ink, an ejection head for ejecting ink to form a printing layer, and a heating means for heating an object to be printed. The ink has a clear ink containing resin and water and a color ink containing resin, pigment, and water, and the color ink contains cyan ink, and the content of the resin in the cyan ink. The mass ratio (P / R) of the cyan pigment content P to R satisfies 0.08 or more and 0.20 or less, and the inkjet printing apparatus is a printing apparatus that prints clear ink on color ink. It has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. _{The temperature of the object} to be printed in the low-gloss print area to be printed in the glossy print mode is set to Low (° C.), and the object to be printed in the high-gloss print area to be printed in the high-gloss print mode when the clear ink is adhered onto the color ink. When the temperature of is T _high (° C.), it is _{heated so as to satisfy the following equation, T low} > T _high , and further has other means if necessary.

Further, one aspect of the inkjet printing apparatus of the present invention is an inkjet printing apparatus having an ink accommodating portion for accommodating ink, an ejection head for ejecting ink to form a printing layer, and a heating means for heating an object to be printed. The ink has a clear ink containing resin and water and a color ink containing resin, pigment, and water, and the color ink contains cyan ink and is a resin in the cyan ink. The mass ratio (P / R) of the cyan pigment content P to the content R satisfies 0.08 or more and 0.20 or less, and the inkjet printing apparatus is a printing apparatus that prints clear ink on color ink. It has a low-gloss printing mode which is a printing mode for imparting low gloss and a high-gloss printing mode which is a printing mode for imparting high gloss, and the temperature of the heating means in the low-gloss printing mode is set to HT _low (° C.). _Assuming that the temperature of the heating means in the high-gloss printing mode is HT high (° C.), the _{heating means is heated so as to satisfy the following equation, HT low} > H _high , and further has other means as needed.

The inkjet printing method of the present invention is an inkjet printing method including a printing step of ejecting ink onto a printed object to provide a printing layer and a heating step of heating the printed object to be printed, wherein the ink is a resin. , And a clear ink containing water, and a color ink containing resin, a pigment, and water. The color ink contains a cyan ink, and the content of the cyan pigment with respect to the content R of the resin in the cyan ink. The mass ratio (P / R) of P satisfies 0.08 or more and 0.20 or less, and the inkjet printing method is a printing method for printing clear ink on color ink in a printing mode for imparting low gloss. It has a low-gloss printing mode and a high-gloss printing mode that imparts high gloss, and prints in the low-gloss printing mode when the clear ink is adhered onto the color ink in the heating step. _{The temperature of the object} to be printed in the print area is T _{low (° C.), and the temperature of the object} to be printed in the high-gloss print area to be printed in the high-gloss printing mode when the clear ink is adhered onto the color ink is High (° C.). Then, it is heated so as to satisfy the following equation, T _low > T _high , and further includes other steps as necessary.

Conventionally, a method of controlling the glossiness of a formed image by adjusting the minimum film forming temperature of the ink has been proposed.
However, a color ink containing a coloring material as in Patent Document 1 cannot obtain a sufficient difference between high gloss and low gloss due to the influence of unevenness of the coloring material, and cannot cope with both low gloss and high gloss control. .. Further, even when a clear ink containing no coloring material is used in combination with the color ink as in Patent Document 2, it is difficult to control the film formation state of the ink layer, and a sufficient difference between high gloss and low gloss can be obtained. It is not possible to support both low-gloss and high-gloss control.
On the other hand, Patent Document 3 has a problem that it has a strong odor because it is an ultraviolet (UV) curable ink, although it can obtain a sufficient glossiness with low gloss and high gloss, and the odor remains in the printed matter. , Not suitable for printed matter for indoor use. For this reason, the installation location of the inkjet printing device also requires an environment in which exhaust can be exhausted, and the installation location is limited. Further, the ultraviolet curable ink requires an ultraviolet irradiation device, and there is a problem that the device becomes large and the cost increases.
Further, Cited Document 4 describes a water-based ink for inkjet that is excellent in printing suitability on a substrate having low water absorption and can obtain a high-quality image, but does not describe color unevenness. It is considered difficult to suppress color unevenness when productivity is increased.
The inkjet printing apparatus and the inkjet printing method of the present invention are based on these findings.

The inkjet printing apparatus and inkjet printing method of the present invention use clear ink containing resin and water and color ink containing resin, pigment, and water, and have both high gloss and low gloss by controlling the heating temperature. Take control. The inkjet printing apparatus and inkjet printing method of the present invention have a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. The low-gloss printing mode is a mode in which the heating temperature is controlled in order to perform low-gloss printing. The high-gloss printing mode is a mode in which the heating temperature is controlled in order to perform high-gloss printing.
When low gloss is applied, printing is performed at a higher printing temperature than in the high gloss printing mode. Since the temperature at the time of printing is high, the clear ink containing resin suppresses the wetting and spreading of dots and the coalescence of adjacent dots, and forms dots having a high dot sphere height (pile height). These dots form surface irregularities and impart low gloss.
On the other hand, when high gloss is applied, printing is performed at a lower temperature than in the low gloss printing mode. Since the temperature at the time of printing is low, the clear ink containing the resin promotes the wetting and spreading of dots and the coalescence of adjacent dots, forms a smooth surface, and imparts high gloss.

Therefore, the inkjet printing apparatus of the present invention uses a clear ink containing resin and water and a color ink containing resin, pigment, and water to impart low gloss to the low gloss printing mode and the low gloss printing mode. It has a high-gloss printing mode, which is a printing mode for imparting high gloss, and the heating means is the temperature of the _{object to be printed in the low-gloss printing area where clear ink is printed on the color ink in the low-gloss printing mode.} When a high-gloss print region of the substrate temperature _{T high} printing a clear ink onto the color ink in high gloss print mode (℃), but heating to satisfy the following _equation, T _{low> T high,} or, The temperature of the heating means when printing the clear ink on the color ink in the low-gloss printing mode HT _low (° C) and the temperature of the heating means when printing the clear ink on the color ink in the high-gloss printing mode HT _high ( By satisfying the following equation, HT _low > HT _high , it is possible to support both low-gloss and high-gloss control.

The heating means of the printing apparatus of the present invention heats the printed matter so that the temperature of the printed matter _{satisfies the following equation, T low} > T _high , and the following equation, T _{low −} T _high ≧ 10 ° C. It is preferable, and it is more preferable to heat so as to satisfy _{the following formula, T low −} T _{high ≧ 20 ° C.}
As a result, in the low-gloss printing mode, the heating temperature is raised, the wet spread of the dots is suppressed, dots with a high pile height are formed, and a surface having large irregularities is formed. On the other hand, in the high-gloss printing mode, the heating temperature can be lowered to promote the wetting and spreading of dots, and the coalescence of adjacent dots can form a smooth surface.

_{The temperature of the object to} be printed in the low-gloss printing area for printing the clear ink on the color ink in the low-gloss printing mode is preferably 50 ° C. or higher, more preferably 50 ° C. or higher and 80 ° C. or lower.
_{The temperature (° C.) of the object to} be printed in the high-gloss printing area where the clear ink is printed on the color ink in the high-gloss printing mode is preferably 70 ° C. or lower, more preferably 60 ° C. or lower.
By setting such a temperature range, it is possible to realize a large change in glossiness in each printing mode using clear ink.
The temperature of the object to be printed in the low-gloss print area and the high-gloss print area can be measured, for example, by installing a thermocouple on the recording medium as the object to be printed and directly measuring the temperature of the recording medium, or using a heater for heating the recording medium. Examples thereof include a method of measuring the temperature and using it as the recording medium temperature, and a method of measuring the ambient temperature of the recording medium in a non-contact manner with a radiation type thermometer or the like and using it as the recording medium temperature.

_{In the present invention, assuming} that the print rate of the low-gloss print image printed in the low-gloss print mode is D low and the print rate of the high-gloss print image printed in the high-gloss print mode is D _high , the following equation, D _high > It is preferable to satisfy D _low , and it is more preferable to satisfy the following formula, D _high −D _low > 10%.
The higher the printing rate, the easier it is for a smooth surface to be formed. Therefore, in the high-gloss printing mode, the image has a high printing rate. On the other hand, in the low-gloss printing mode, when the printing rate is high, adjacent dots are coalesced and surface irregularities are less likely to be formed, so that the image has a low printing rate.
Here, the printing rate means the following.
Printing rate (%) = number of clear ink printing dots / (vertical resolution x horizontal resolution) x 100
(However, in the above formula, the "number of clear ink printing dots" is the number of dots actually printed with clear ink per unit area, and the "vertical resolution" and "horizontal resolution" are the resolutions per unit area, respectively. When the clear inks are printed in layers so that the dot positions are the same, the "clear ink printing dot number" is represented by the total number of dots actually printed with the clear ink per unit area.)
The printing rate of 100% means the maximum weight of a single color ink with respect to a pixel.

<Ink storage>
The ink accommodating portion stores ink.
The ink accommodating portion is not particularly limited as long as it is a member capable of accommodating ink, and examples thereof include an ink accommodating container and an ink tank.
The ink container includes the ink contained in the container, and further includes other members appropriately selected as needed.
The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, an ink bag made of an aluminum laminate film, a resin film, or the like can be used. At least those who have it can be mentioned.
Examples of the ink tank include a main tank and a sub tank.

<Discharge head>
The ejection head ejects ink to form a print layer.
The discharge head has a nozzle plate, a pressurizing chamber, and a stimulus generating means.

-Nozzle plate-
The nozzle plate has a nozzle substrate and an ink-repellent film on the nozzle substrate.

-Pressure chamber-
The pressurizing chamber is a plurality of individual flow paths that are individually arranged corresponding to the plurality of nozzle holes provided in the nozzle plate and communicate with the nozzle holes, and are an ink flow path, a pressurized liquid chamber, and the like. It may also be called a pressure chamber, a discharge chamber, a liquid chamber, or the like.

-Stimulation generating means-
The stimulus generating means is a means for generating a stimulus applied to the ink.
The stimulus in the stimulus generating means is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include heat (temperature), pressure, vibration and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferably mentioned.
Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generator, an ultrasonic oscillator, and a light. Specific examples of the stimulus generating means include a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes an electrothermal conversion element such as a heat generating resistor to utilize a phase change due to boiling of an ink film, and a metal phase change due to a temperature change. Examples thereof include a shape memory alloy actuator using the above and an electrostatic actuator using an electrostatic force.

When the stimulus is "heat", heat energy corresponding to the recording signal is applied to the ink in the ink ejection head by using, for example, a thermal head. Examples thereof include a method in which bubbles are generated in the ink by the heat energy and the ink is discharged as droplets from the nozzle holes of the nozzle plate by the pressure of the bubbles.
When the stimulus is "pressure", for example, the piezoelectric element bends by applying a voltage to the piezoelectric element adhered to a position called the pressure chamber in the ink flow path in the ink ejection head. .. As a result, the volume of the pressure chamber contracts, and the ink is ejected as droplets from the nozzle hole of the ink ejection head.
Among these, the piezo method in which a voltage is applied to the piezo element to fly the ink is preferable.

<Heating means>
The heating means heats the printed matter.
Examples of the heating means include means for heating and drying the printed surface and the back surface of the recording medium as the printed matter, and examples thereof include an infrared heater, a warm air heater, and a heating roller. These may be used alone or in combination of two or more.

The method for drying the recording medium as the object to be printed is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a heated fluid such as warm air is used as a drying means on the recording medium to which the ink is applied. A method of contacting a recording medium to which ink is applied and a heating member to heat by heat transfer, a method of heating a recording medium to which ink is applied by irradiating energy rays such as infrared rays and far infrared rays. And so on.
The heating can be performed at least before printing, during printing, and after printing.
By heating before and during printing, it becomes possible to print on a heated medium, and by heating after printing, the printed matter can be dried.
The heating time is not particularly limited as long as the surface temperature of the recording medium can be controlled to a desired temperature, and can be appropriately selected depending on the intended purpose.
The heating time is preferably controlled by controlling the transport speed of the recording medium as the printed matter.

_{As described above, the temperature HT (° C.) of the heating means is the temperature HT low} (° C.) of the heating means when printing the clear ink on the color ink in the low gloss printing mode and the clear ink in the high gloss printing mode. It is preferable that _{the temperature HT high} (° C.) of the heating means when printing on the color ink _{satisfies the following equation, HT low} > HT _high , and HT _low −HT _{high ≧ 10 ° C.} The temperature HT (° C.) of the heating means is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the set temperature of the heating means can be used.

(ink)
As the ink, clear ink and color ink are used.
The clear ink means a colorless and transparent ink that does not substantially contain a coloring material, and the color ink means an ink that contains a coloring material such as a pigment or a dye.
The clear ink and the color ink are preferably a clear ink and a color ink containing water as a solvent, and may contain an organic solvent if necessary.
The clear ink and the color ink contain water and a resin, preferably contain a surfactant, and further contain other components as necessary.

The cyan ink contained in the color ink satisfies the mass ratio (P / R) of the content P of the cyan pigment to the content R of the resin in the cyan ink of 0.08 or more and 0.20 or less.
Color unevenness that occurs due to landing misalignment or the like when the productivity of an inkjet printing apparatus is improved is particularly easy to recognize in cyan color. Therefore, reducing the density of one dot of cyan ink has a high effect of suppressing color unevenness. Further, in order to achieve both color unevenness and the fastness of the ink coating film, it is possible to cover by lowering the mass ratio (P / R) of the pigment content / resin content in the ink (increasing the resin content). I found it. Further, in order to achieve both color reproducibility, when forming a mixed black composed of black ink, cyan ink, magenta ink, and yellow ink, the pigment contents of the black ink and the magenta ink are made the same to make gray. We found that the balance was improved.
Further, in order to obtain the above effect, the content of the cyan pigment is preferably 0.8% by mass or more and 1.5% by mass or less, and 1.0% by mass or more and 1.3% by mass or less. Is more preferable. Further, both the content of the black pigment and the content of the magenta pigment are preferably 2.0% by mass or more and 4.0% by mass or less, and 2.5% by mass or more and 3.5% by mass or less. More preferred.
As described above, the ink of the present invention can suppress color unevenness, but in particular, it is provided with an ejection means having four or more nozzle rows in which a plurality of nozzle holes for ejecting ink are arranged in a sub-scanning direction orthogonal to the main scanning direction. It is preferably used in a wide printing apparatus, and more preferably used in a wide printing apparatus provided with ejection means having 8 or more nozzle rows. This enables high-speed printing and greatly improves productivity.

The clear ink and the color ink of the present invention will be described below. Hereinafter, these may be collectively referred to simply as "ink".

<Water>
The water is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ion-exchanged water, ultrafiltration water, reverse osmosis water, pure water such as distilled water, and ultrapure water. .. These may be used alone or in combination of two or more.
The water content is preferably 15% by mass or more and 60% by mass or less with respect to the total amount of ink. When the content is 15% by mass or more, high viscosity can be prevented and discharge stability can be improved. On the other hand, when it is 60% by mass or less, the wettability to the impermeable recording medium becomes preferable, and the image quality can be improved.

<Resin>
The resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyurethane resin, a polyester resin, an acrylic resin, a vinyl acetate resin, a styrene resin, a butadiene resin, a styrene-butadiene resin, and a vinyl chloride resin can be selected. , Acrylic-styrene resin, acrylic-silicone resin and the like.
When producing ink, it is preferable to add it as resin particles made of these resins.
Resin particles may be added to the ink in the form of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. These may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles. Among these, polyurethane resin is preferable as the clear ink. By adding the polyurethane resin, the coating film itself becomes tough when an ink film is formed using clear ink. As a result, it is preferable because it is easy to prevent the inside of the coating film from being broken and a part of the coating film from being peeled off or the surface state of the coating film being changed to change the color of the friction portion.
Further, the color ink is also preferably a polyurethane resin. Not only is it difficult for the pigment to settle on a non-permeable recording medium, but when the amount of adhesion between colors is different, fine irregularities are generated on the image surface, which causes color unevenness. By including the urethane resin in the ink, it is possible to improve both the fixability on the non-permeable recording medium and the uniformity of the image surface.

-Polyurethane resin-
Examples of the polyurethane resin include a polyether polyurethane resin, a polycarbonate polyurethane resin, and a polyester polyurethane resin.

The polyurethane resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polyurethane resin obtained by reacting a polyol with a polyisocyanate.

-Polyol-
Examples of the polyol include polyether polyols, polycarbonate polyols, polyester polyols and the like. These may be used alone or in combination of two or more.

-Polyether polyol-
Examples of the polyether polyol include those obtained by addition polymerization of an alkylene oxide using at least one compound having two or more active hydrogen atoms as a starting material.

Examples of the compound having two or more active hydrogen atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylolglycol, 1,3-butanediol, 1,4-butanediol, and 1,6-hexane. Examples thereof include diol, glycerin, trimethylolethane, and trimethylolpropane. These may be used alone or in combination of two or more.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran. These may be used alone or in combination of two or more.

The polyether polyol is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining an ink binder capable of imparting extremely excellent scratch resistance, polyoxytetramethylene glycol and polyoxy Propylene glycol is preferred. These may be used alone or in combination of two or more.

-Polycarbonate polyol-
Examples of the polycarbonate polyol that can be used in the production of the polyurethane resin include those obtained by reacting a carbonic acid ester with a polyol, and those obtained by reacting phosgene with bisphenol A and the like. These may be used alone or in combination of two or more.

Examples of the carbonic acid ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like. These may be used alone or in combination of two or more.

Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1, 2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8 − Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcin , Bisphenol-A, Bisphenol-F, 4,4'-biphenol and other relatively low molecular weight dihydroxy compounds; Polyether polyols such as polyethylene glycol, polypropylene glycol and polyoxytetramethylene glycol; Polyhexamethylene adipate, polyhexamethylene Examples thereof include polyester polyols such as succinate and polycaprolactone. These may be used alone or in combination of two or more.

-Polyester polyol-
Examples of the polyester polyol include those obtained by esterifying a low molecular weight polyol and a polycarboxylic acid, polyester obtained by ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymerization thereof. Examples include polyester. These may be used alone or in combination of two or more.

Examples of the low molecular weight polyol include ethylene glycol and propylene glycol. These may be used alone or in combination of two or more.
Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, dodecandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, anhydrides or ester-forming derivatives thereof. These may be used alone or in combination of two or more.

-Polyisocyanate-
Examples of the polyisocyanate include aromatic diisocyanates such as phenylenediocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalenedi isocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxyl Examples thereof include aliphatic or alicyclic diisocyanates such as range isocyanate and 2,2,4-trimethylhexamethylene diisocyanate. These may be used alone or in combination of two or more. Among these, alicyclic diisocyanate is preferable from the viewpoint of weather resistance.

Further, by using at least one kind of alicyclic diisocyanate, it becomes easy to obtain the desired coating film strength and scratch resistance.
Examples of the alicyclic diisocyanate include isophorone diisocyanate and dicyclohexylmethane diisocyanate.
The content of the alicyclic diisocyanate is preferably 60% by mass or more with respect to the total amount of the isocyanate compound.

[Manufacturing method of polyurethane resin]
The polyurethane resin is not particularly limited and can be obtained by a conventionally commonly used production method, and examples thereof include the following methods.
First, an isocyanate-terminated urethane prepolymer is produced by reacting the polyol with the polyisocyanate at an equivalent ratio in which the isocyanate group becomes excessive in the absence of a solvent or in the presence of an organic solvent.
Then, the anionic group in the isocyanate-terminated urethane prepolymer is neutralized with a neutralizing agent if necessary, and then reacted with a chain extender, and finally the organic solvent in the system is removed if necessary. Can be obtained by

Examples of the organic solvent that can be used for producing the polyurethane resin include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetate esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide. , N-Methylpyrrolidone, N-ethylpyrrolidone and other amides. These may be used alone or in combination of two or more.
Examples of the chain extender include polyamines and other active hydrogen group-containing compounds.

Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazin, isophoronediamine, 4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexane. Diamines such as diamines; Polyamines such as diethylenetriamine, dipropylenetriamine, and triethylenetetramine; Hydradins such as hydrazine, N, N'-dimethylhydrazine, and 1,6-hexamethylenebishydrazine; dihydrazide succinate, dihydrazide adipic acid , Glutarate dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide and other dihydrazides. These may be used alone or in combination of two or more.

Examples of the other active hydrogen group-containing compound include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and hexamethylene glycol. Glycos such as saccharose, methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone, etc. Kind: Water and the like. These may be used alone or in combination of two or more as long as the storage stability of the ink is not deteriorated.

As the polyurethane resin, a polycarbonate-based polyurethane resin is preferable from the viewpoints of water resistance, heat resistance, abrasion resistance, weather resistance, and scratch resistance of images due to the high cohesive force of carbonate groups. In the case of the polycarbonate-based polyurethane resin, an ink suitable for a recorded material used in a harsh environment such as outdoor use can be obtained.

As the polyurethane resin, a commercially available product may be used, for example, U-coat UX-485 (polyurethane-based polyurethane resin), U-coat UWS-145 (polyurethane-based polyurethane resin), Permarin UA-368T (polyurethane-based polyurethane resin), and the like. Permarin UA-200 (polyether-based polyurethane resin) (all manufactured by Sanyo Kasei Kogyo Co., Ltd.) and the like can be mentioned. These may be used alone or in combination of two or more.

The content of the resin contained in the clear ink is preferably 8% by mass or more, preferably 8% by mass or more and 25% by mass, from the viewpoint that low gloss and high gloss can be controlled with a small amount of clear ink and the ejection stability of the ink is improved. The following is more preferable. When the resin content is 8% by mass or more, low gloss and high gloss can be controlled with a small amount of clear ink.

Low gloss is realized by forming isolated dots with a high height of the dot sphere (pile height) and imparting irregularities on the surface.
When the content of the resin in the clear ink is large, dots having a high pile height are likely to be formed, which is preferable from the viewpoint of easily imparting low gloss.
On the other hand, high gloss imparts smoothness by filling the unevenness of the surface with clear ink to form a smooth surface. In order to fill the unevenness of the surface with clear ink, it is preferable that the content of the resin in the clear ink is large because the unevenness of the surface can be filled with a small amount of clear ink and high gloss can be easily imparted.

<Surfactant>
The ink preferably contains a surfactant.
By adding a surfactant to the ink, the surface tension is reduced and the ink droplets permeate into the recording medium after landing on the recording medium such as paper, so that feathering and color bleeding can be reduced. Can be done.
Surfactants are classified into nonionic, anionic and amphoteric according to the polarity of the hydrophilic group.
Further, it is classified into fluorine type, silicone type, acetylene type and the like according to the structure of the hydrophobic group.

As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, and side chain double-ended modified polydimethylsiloxane. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. The counterions of the salts in these fluorine-based surfactants are Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). _3rd grade can be mentioned.
Examples of the amphoteric tenside agent include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, salt of polyoxyethylene alkyl ether sulfate, and the like.
These may be used alone or in combination of two or more.

（但し、一般式（Ｓ−１）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ−６１８、ＫＦ−６４２、ＫＦ−６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ−ＳＳ−５６０２、ＳＳ−１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ−２１０５、ＦＺ−２１１８、ＦＺ−２１５４、ＦＺ−２１６１、ＦＺ−２１６２、ＦＺ−２１６３、ＦＺ−２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ−３３、ＢＹＫ−３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain-modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, side. Examples thereof include polydimethylsiloxane modified at both ends of the chain, and a polyether-modified silicone-based surfactant having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as modifying groups exhibits good properties as an aqueous surfactant, and is particularly effective. preferable.
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. As commercially available products, for example, they can be obtained from Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above-mentioned polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polyalkylene oxide structure represented by the general formula (S-1) is dimethylpoly. Examples thereof include those introduced into the Si part side chain of siloxane.
[General formula (S-1)]

(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R'represents an alkyl group.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like can be mentioned.

上記一般式（Ｆ−１）で表される化合物において、水溶性を付与するためにｍは０〜１０の整数が好ましく、ｎは０〜４０の整数が好ましい。 As the fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorine-based surfactant include a perfluoroalkyl phosphate compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferable because they have low foaming property, and are particularly fluorine-based compounds represented by the general formulas (F-1) and (F-2). Surfactants are preferred.
[General formula (F-1)]

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40 in order to impart water solubility.

[General formula (F-2)]
C _n F _{2n + 1-} CH ₂ CH (OH) CH _2- O- (CH ₂ CH ₂ O) _a- Y
In the compound represented by the above general formula (F-2), Y is H or CmF _{2m + 1} and m is an integer of 1 to 6, or CH ₂ CH (OH) CH _2- CmF _{2m + 1} and m is 4 to 6. It is an integer, or CpH _{2p + 1} and p is an integer of 1-19. n is an integer of 1-6. a is an integer of 4 to 14.
Commercially available products may be used as the above-mentioned fluorine-based surfactant.
Examples of this commercially available product include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by The Chemours Company); FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omniova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc. Among these, FS-3100, FS-34, and FS-300 manufactured by The Chemours Company are found to significantly improve good print quality, particularly color development, paper permeability, wettability, and leveling property. , FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omniova Co., Ltd. and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. Is particularly preferable.

The content of the surfactant in the clear ink is preferably 2.0% by mass or less, more preferably 0.05% by mass or more and 2% by mass or less, and further preferably 0.1% by mass or more and 2% by mass or less. By setting the content of the surfactant to 2% by mass or less, a large decrease in glossiness can be obtained in the low gloss printing mode.
On the other hand, the content of the surfactant in the color ink is not particularly limited and can be appropriately selected depending on the intended purpose. However, 0.001 is obtained because it is excellent in wettability and ejection stability and the image quality is improved. It is preferably by mass% or more and 5% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less.
Further, from the viewpoint of improving color unevenness, it is preferable that the surfactant of the color ink contains a siloxane compound.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. For example, polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds and the like can be mentioned. The term "water-soluble" means that, for example, 5 g or more is dissolved in 100 g of water at 25 ° C.

Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2 , 3-Butandiol, 3-Methyl-1,3-Butandiol, Triethylene Glycol, Polyethylene Glycol, Polypropylene Glycol, 1,2-Pentanediol, 1,3-Pentanediol, 1,4-Pentanediol, 2, 4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1 , 2,6-Hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3 -Polyhydric alcohols such as pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. Polyhydric alcohol aryl ethers such as polyhydric alcohol alkyl ethers, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1, Nitrogen-containing heterocyclic compounds such as 3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide. , Amids such as 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate and the like. Be done. These may be used alone or in combination of two or more.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used.
Examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Examples of the glycol ether compound include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Kind: Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of ink drying property and ejection reliability. More preferably, it is 20% by mass or more and 60% by mass or less.

<Pigment>
The color ink of the present invention has a pigment.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Moreover, you may use a mixed crystal.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy color pigment such as gold or silver, a metallic pigment, or the like can be used.
As the inorganic pigment, for example, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, it is produced by a known method such as a contact method, a furnace method, or a thermal method. Carbon black can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acidic dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).
Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36 and the like. These may be used alone or in combination of two or more.

When a pigment is used as a coloring material, as a method of dispersing the pigment in the ink, for example, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, or a method of coating the surface of the pigment with a resin and dispersing the pigment. Examples thereof include a method and a method of dispersing using a surfactant or a polymer-type dispersant.
Examples of the method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment include a self-dispersing pigment in which a functional group such as a sulfone group or a carboxyl group is added to a pigment (for example, carbon) so that the pigment can be dispersed in water. Can be mentioned.
As a method of coating the surface of the pigment with a resin and dispersing it, for example, a method in which the pigment is encapsulated in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin coating pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effects of the present invention are not impaired. May be.
Examples of the method of dispersing using a surfactant or a polymer-type dispersant include a method of dispersing using a known surfactant and a polymer-type dispersant.
Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants and the like.
Examples of the polymer-type dispersant include polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-alkyl ester copolymer, and styrene-. Acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid-acrylic acid alkyl ester copolymer, stin-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer Polymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-maleic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl-ethylene homoweight Examples thereof include coalescence, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer, modified polyurethane and the like.
In addition, a naphthalene sulfonate Na formalin condensate or the like can also be used as a dispersant.
These may be used alone or in combination of two or more.
<Pigment dispersion>

It is possible to obtain an ink by mixing materials to be added to the ink such as pigments, water, organic solvents, and other materials. Further, it is preferable to add water, a pigment, and if necessary, a dispersant to form a pigment dispersion to obtain an ink.
The pigment dispersion is obtained by mixing water, a pigment, a pigment dispersant, and other components as necessary, dispersing them with a disperser, and adjusting the particle size.
The particle size of the pigment is not particularly limited, but when the maximum frequency is 20 nm or more and 150 nm or less in terms of the maximum number, the dispersion stability of the pigment is good, and the image quality such as ejection stability and image density is also improved. Higher and preferable. The particle size of the pigment can be measured using a particle size analyzer (Microtrack MODEL UPA9340, manufactured by Nikkiso Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.1% by mass or more and 50% by mass or less, and 0.1% by mass or more and 30% by mass or more. The following is more preferable.
If necessary, the pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifuge, or the like.

<Additives>
The ink may contain an antifoaming agent, an antiseptic antifungal agent, a rust preventive agent, a pH adjuster and the like as other components, if necessary.

-Defoamer-
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

-Preservatives and fungicides-
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

-Rust inhibitor-
The rust preventive is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

-PH regulator-
The pH adjusting agent is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

<Ink physical characteristics>
The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80L) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'x R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less, more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, more preferably 8 to 11, from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

(Printed matter)
The printed matter is not limited to that used as a recording medium, and for example, wallpaper, flooring materials, building materials such as tiles, clothing cloth such as T-shirts, textiles, leather and the like can be appropriately used. By adjusting the configuration of the path for transporting the recording medium, ceramics, glass, metal, or the like can be used as the printed matter.
The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, or the like can be used, but good image formation can be achieved even if a non-permeable base material is used.
The non-permeable base material is a base material having a surface having low water permeability and low absorbability, and includes a material that does not open to the outside even if there are many cavities inside, and more quantitatively. , A base material having a water absorption amount of 10 mL / m ² or less from the start of contact to 30 msec ^{1/2 in the Bristow method.}
As the non-permeable substrate, for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, an acrylic resin film, a polypropylene film, a polyethylene film, or a polycarbonate film can be preferably used.

In the present invention, in the low-gloss printing mode, it is preferable to use a printed matter having a high glossiness. A printed matter having a high glossiness is preferable because the low gloss effect of the clear ink is easily emphasized.
On the other hand, in the high-gloss printing mode, it is preferable to use a printed matter having a low glossiness. A printed matter having a low glossiness is preferable because the high gloss effect of the clear ink is easily emphasized.
Therefore, the glossiness of the substrate used in the low gloss printing mode and _{G low,} the glossiness of the substrate and _{G high} for use in high gloss print mode, it is preferable to satisfy the following _{equation, low> G high,} the following equation , G _{low −} G _high ≧ 100, more preferably.

(Gloss control method for printed images)
The gloss control method for a printed image of the present invention is a gloss control method for a printed image including a printing step of ejecting ink to a printed matter to provide a print layer and a heating step of heating the printed printed matter. The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water. The color ink contains cyan ink, and the resin content R in the cyan ink. The mass ratio (P / R) of the content P of the cyan pigment to the amount P is 0.08 or more and 0.20 or less, and the gloss control method of the printed image is a low gloss printing mode and a high gloss printing mode which imparts low gloss. It has a high-gloss printing mode, which is a printing mode for imparting gloss, and when printing in the low-gloss printing mode, control is performed to raise the heating temperature as compared with the case of printing in the high-gloss printing mode. When printing in the high-gloss printing mode, control is performed to lower the heating temperature as compared with the case of printing in the low-gloss printing mode.
When printing in the low-gloss printing mode, the heating temperature is higher than in the case of printing in the high-gloss printing mode, which means that the absolute temperature (thermodynamic temperature) of the printing medium heated by the heating means in the low-gloss printing mode is high. ) Is higher than the absolute temperature (thermodynamic temperature) of the printing medium heated by the heating means in the high-gloss printing mode.
Further, when printing in the high-gloss printing mode, the heating temperature is lowered as compared with the case of printing in the low-gloss printing mode, which means that the absolute temperature (heat) of the printing medium heated by the heating means in the high-gloss printing mode is set. It means that the dynamic temperature) is lower than the absolute temperature (thermodynamic temperature) of the printing medium heated by the heating means in the low gloss printing mode.

(Printed matter)
The printed matter is a printed matter having a printed matter and a printed layer on the printed matter.
The printing layer is composed of a color ink layer containing a resin and a clear ink layer.
The printed matter has a low-gloss print image printed in the low-gloss print mode and a high-gloss print image printed in the high-gloss print mode.
The glossiness difference (Ga-Gb) between the 60 ° glossiness Ga of the high-gloss printed image and the 60 ° glossiness Gb of the printed matter used in the high-gloss printing mode is 20 or more.
The glossiness difference (Gc−Gd) between the 60 ° glossiness Gc of the low-gloss printed image and the 60 ° glossiness Gd of the printed matter used in the low-gloss printing mode is −20 or less.
The printed matter can be obtained by forming an image on a recording medium by the inkjet printing apparatus and the inkjet printing method of the present invention.

(Recording device, recording method)
In the following description of the recording device and the recording method, the case where black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink are used will be described, but in addition to these, clear ink will be described. Should be used.
The clear ink used in the present invention can be suitably used for various recording devices by an inkjet recording method, for example, a printer, a facsimile device, a copying device, a printer / fax / copier multifunction device, a three-dimensional modeling device, and the like.
Unless otherwise specified, the inkjet printing apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head.
Further, the inkjet printing device includes not only a desktop type but also a wide recording device and a continuous book printer capable of using, for example, continuous paper wound in a roll shape as a recording medium.
In the present invention, the recording device and the recording method are devices capable of ejecting ink and various processing liquids to a recording medium, and a method of recording using the device. The recording medium means a medium to which ink and various treatment liquids can adhere even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means related to feeding, transporting, and discharging paper of a recording medium, and other devices called pretreatment devices and posttreatment devices. ..
Further, the recording device and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, those that form patterns such as geometric patterns and those that form a three-dimensional image are also included.
Further, the recording device includes both a serial type device that moves the discharge head and a line type device that does not move the discharge head, unless otherwise specified.
Further, for this recording device, it is possible to use not only a desktop type but also a wide recording device capable of printing on an A0 size recording medium, for example, continuous paper wound in a roll shape as a recording medium. A continuous line printer is also included.
An example of the recording device will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective explanatory view of the recording device. FIG. 2 is a perspective explanatory view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanical unit 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink container 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is, for example, an aluminum laminate film or the like. It is made of packaging members. The ink container 411 is housed in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided behind the opening when the cover 401c of the apparatus main body is opened. A main tank 410 is detachably attached to the cartridge holder 404. As a result, each ink ejection port 413 of the main tank 410 and the ejection head 434 for each color communicate with each other via the supply tube 436 for each color, and ink can be ejected from the ejection head 434 to the recording medium.

This recording device can include not only a portion that ejects ink, but also a device called a pretreatment device, a posttreatment device, and the like.
As one aspect of the pretreatment device and the posttreatment device, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a liquid having a pretreatment liquid and a posttreatment liquid. There is an embodiment in which a storage unit and a liquid discharge head are added, and the pretreatment liquid and the posttreatment liquid are discharged by an inkjet recording method.
As another aspect of the pretreatment device and the posttreatment device, there is a mode in which a pretreatment device and a posttreatment device by, for example, a blade coating method, a roll coating method, and a spray coating method are provided other than the inkjet recording method.

The method of using the ink is not limited to the inkjet recording method, and can be widely used. In addition to the inkjet recording method, examples thereof include a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, and a spray coating method.

The use of the ink is not particularly limited and can be appropriately selected depending on the purpose, and can be applied to, for example, printed matter, paint, coating material, base material and the like. Further, it can be used not only as an ink to form two-dimensional characters and images, but also as a material for three-dimensional modeling for forming a three-dimensional three-dimensional image (three-dimensional model).
A known three-dimensional modeling device can be used for modeling the three-dimensional object, and the device is not particularly limited, but for example, an device provided with ink accommodating means, supply means, ejection means, drying means, and the like is used. be able to. The three-dimensional model includes a three-dimensional model obtained by overcoating with ink. In addition, a molded product obtained by processing a structure in which ink is applied on a base material such as a recording medium is also included. The molded product is, for example, a sheet-shaped or film-shaped recorded material or structure that has been subjected to molding processing such as heat stretching or punching, and is, for example, an automobile, OA equipment, or electricity. -Suitably used for molding after decorating the surface of electronic devices, meters for cameras, panels of operation parts, etc.

In addition, image formation, recording, printing, printing, etc. in the terms of the present invention are all synonymous.

Recording media, media, and printed matter are all synonymous.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

(Manufacturing Example 1)
<Preparation of Polycarbonate Polyurethane Resin Emulsion 1>
Polycarbonate diol (reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1,200)) 1,500 mass in a reaction vessel containing a stirrer, a reflux cooling tube, and a thermometer. 220 parts by mass of 2,2-dimethylolpropionic acid (hereinafter, also referred to as "DMPA"), and 1,347 parts by mass of N-methylpyrrolidone (hereinafter, also referred to as "NMP") are nitrogen. It was charged under an air stream and heated to 60 ° C. to dissolve DMPA.
Next, 1,445 parts by mass of 4,4'-dicyclohexylmethane diisocyanate and 2.6 parts by mass of dibutyltin dilaurylate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was carried out over 5 hours to carry out a urethanization reaction at the isocyanate terminal. Urethane prepolymer was obtained. The reaction mixture was cooled to 80 ° C., 149 parts by mass of triethylamine was added thereto, 4,340 parts by mass was extracted from the mixture, and 5,400 parts by mass of water and 15 parts by mass of triethylamine were extracted under strong stirring. Was added to the mixed solution of.
Next, 1,500 parts by mass of ice was added, and 626 parts by mass of a 35% by mass 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction so that the solid content concentration became 30% by mass. The solvent was distilled off from the mixture to obtain a polycarbonate-based polyurethane resin emulsion 1.
The obtained polycarbonate-based polyurethane resin emulsion was measured with a "film-forming temperature tester" (manufactured by Imoto Seisakusho Co., Ltd.), and the minimum film-forming temperature was 55 ° C.

(Manufacturing Example 2)
<Preparation of acrylic resin emulsion 1>
900 parts by mass of ion-exchanged water and 1 part by mass of sodium lauryl sulfate were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer, and the temperature was raised to 70 ° C. while substituting nitrogen under stirring. Keep the internal temperature at 70 ° C., add 4 parts by mass of potassium persulfate as a polymerization initiator, and after dissolution, 450 parts by mass of ion-exchanged water, 3 parts by mass of sodium lauryl sulfate, 20 parts by mass of acrylamide, 365 parts by mass of styrene, The emulsion prepared by adding 545 parts by mass of butyl acrylate and 10 parts by mass of methacrylic acid under stirring was continuously added dropwise into the reaction solution over 4 hours. After completion of the dropping, the mixture was held for 3 hours. After cooling the obtained aqueous emulsion to room temperature, ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the pH to 8, to obtain acrylic resin emulsion 1 (solid content concentration: 30% by mass).

(Manufacturing Example 3)
<Manufacturing of clear ink A>
Polyurethane resin emulsion 1 (solid content concentration: 30% by mass) of Production Example 1 50% by mass, 1,2-propanediol 20% by mass, 1,3-propanediol 11% by mass, 1,2-butanediol 3% by mass , Polysiloxane surfactant (trade name: KF-6017, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) as a surfactant, 1.2% by mass, and a total of 100% by mass of high pure water was added, and the mixture was mixed and stirred. The mixture was prepared.
Next, the obtained mixture was filtered through a polypropylene filter having an average pore size of 0.2 μm (trade name: Betafine polypropylene pleated filter PPG series, manufactured by 3M) to prepare clear ink A.

(Manufacturing Examples 4 to 8)
<Manufacturing of clear inks B to F>
Clear inks B to F were produced in the same manner as in Production Example 3 except that the ink composition was changed to that shown in Table 1.

(Manufacturing Example 9)
<Manufacturing of cyan pigment dispersion>
A cyan pigment dispersion was obtained in the same manner as described in "-Method A- of [Pigment surface modification treatment]" of JP2012-207202A.
Specifically, C.I. I. Pigment Blue 15: 3 (trade name: Chromofine Blue, manufactured by Dainichiseika Kogyo Co., Ltd.), 20 mmol of the compound of the following structural formula (1), and 200 mL of ion-exchanged water in a Slurry mixer at room temperature (25 ° C). (6,000 rpm (0.6 mass%)) was mixed to obtain a slurry. If the pH of the resulting slurry was higher than 4, 20 mmol of nitric acid was added. After 30 minutes, sodium nitrite (20 mmol) dissolved in a small amount of ion-exchanged water was slowly added to the slurry. Further, the mixture was heated to 60 ° C. with stirring and reacted for 1 hour. The C.I. I. A modified pigment having the compound of the following structural formula (1) added to the surface of Pigment Blue 15: 3 was obtained.
Next, the pH was adjusted to 10 with an aqueous NaOH solution to obtain a modified pigment dispersion after 30 minutes. It has a bisphosphonic acid group as a hydrophilic functional group having a pigment concentration of 15% by mass by performing ultrafiltration using a dialysis membrane using the modified pigment dispersion and ion-exchanged water and further performing ultrasonic dispersion. A cyan pigment dispersion (self-dispersed type) was obtained.

[Structural formula (1)]

(Manufacturing Example 10)
<Manufacturing of magenta pigment dispersion>
In Production Example 9 of the pigment dispersion, C.I. I. Pigment Blue 15: 3 (trade name: Chromofine Blue, manufactured by Dainichiseika Kogyo Co., Ltd.) 20 g, C.I. I. Pigment Red 122 (trade name: Toner Magenta EO02, manufactured by Clariant Japan Co., Ltd.) A magenta pigment dispersion having a pigment concentration of 15% by mass was produced in the same manner as in Production Example 9 of the pigment dispersion except that the pigment was changed to 20 g. did.

(Manufacturing Example 11)
<Manufacturing of yellow pigment dispersion>
In Production Example 9 of the pigment dispersion, C.I. I. Pigment Blue 15: 3 (trade name: Chromofine Blue, manufactured by Dainichiseika Kogyo Co., Ltd.) 20 g, C.I. I. Pigment Yellow 74 (trade name: First Yellow 531; manufactured by Dainichiseika Kogyo Co., Ltd.) A yellow pigment dispersion having a pigment concentration of 15% by mass in the same manner as in Production Example 9 of the pigment dispersion except that it was changed to 20 g. Was produced.

(Manufacturing Example 12)
<Manufacturing of black pigment dispersion>
In Production Example 9 of the pigment dispersion, C.I. I. Pigment Blue 15: 3 (trade name: Chromofine Blue, manufactured by Dainichiseika Kogyo Co., Ltd.) was changed to 20 g of carbon black (NIPEX160, manufactured by degussa) in the same manner as in Production Example 9 of the pigment dispersion. A black pigment dispersion having a pigment concentration of 15% by mass was prepared.

(Manufacturing Example 13)
<Manufacturing of color ink set a>
Cyan ink a, magenta ink a, yellow ink a, and black ink a produced as follows were combined to form a color ink set a.
-Manufacturing of cyan ink a-
Cyan pigment dispersion 6.7% by mass, 1,3-butanediol (trade name: 1,3-butanediol, manufactured by Daicel Chemical Co., Ltd.) 20% by mass, 3-methoxy-N, N-dimethylpropionamide (commodity) Name: Equamid M-100, manufactured by Idemitsu Kosan Co., Ltd. 10% by mass, diethylene glycol diethyl ether (trade name: Highsolve EDE, manufactured by Toho Chemical Industry Co., Ltd.) 5% by mass, triethylene glycol butylmethyl ether (trade name: Highsolve BTM) , Toho Chemical Industry Co., Ltd.) 5% by mass, Polycarbonate urethane resin particle solution (Takelac W6110, Mitsui Chemicals Co., Ltd., solid content concentration: 30% by mass) 27.8% by mass, siloxane compound (trade name: FZ2110, Toray) -A membrane filter having an average pore size of 0.8 μm (manufactured by Dow Co., Ltd., active ingredient concentration 100% by mass) 2.5% by mass, and a total of 100% by mass of high pure water added, mixed and stirred. Product name: DISMIC-25cs, manufactured by Advantech Co., Ltd.) to obtain cyan ink a.

-Making magenta ink a-
Magenta ink a was obtained in the same manner as in the production of cyan ink a, except that 6.7% by mass of the cyan pigment dispersion was changed to 20.0% by mass of the magenta pigment dispersion in the production of cyan ink a.

-Making yellow ink a-
In the production of cyan ink a, yellow ink a was obtained in the same manner as in the production of cyan ink a, except that 6.7% by mass of the cyan pigment dispersion was changed to 13.3% by mass of the yellow pigment dispersion.

-Making black ink a-
In the production of cyan ink a, black ink a was obtained in the same manner as in the production of cyan ink a, except that 6.7% by mass of the cyan pigment dispersion was changed to 20.0% by mass of the black pigment dispersion.

(Manufacturing Examples 14 to 25)
<Making color ink sets b to m>
In Production Example 13, the same as in Production Example 13 except that the compositions and contents of cyan ink a, magenta ink a, yellow ink a, and black ink a are changed to the ink compositions and contents shown in Tables 2 to 6. Then, the ink sets b to m of Production Examples 14 to 25 were obtained.
However, as the materials in the table not described above, the following materials were used.
* Acrylic resin emulsion (Boncoat CF-6140, manufactured by DIC Corporation, solid content concentration: 30% by mass)
* Fluorine compound: Zonir FS-300 (manufactured by DuPont)
* Nonion compound: Triton HW1000 (manufactured by Dow Chemical Co., Ltd.)

(Example 1)
<Inkjet printing>
The ink cartridge of the modified machine (manufactured by Ricoh Co., Ltd.), which has one more main tank of the inkjet printer GXe5500 and is capable of ejecting five colors, is filled with the clear ink A of Production Example 3 and the color ink set a of Production Example 13 to fill the ink. The filled ink cartridge was attached to the inkjet printer GXe5500 remodeling machine, and inkjet printing was performed.
The inkjet printer GXe5500 remodeling machine is provided with a heater (temperature control controller, model MTCD, manufactured by Misumi) so that the recording medium can be heated from the back surface before, during, and after printing. As a result, it is possible to print on the recording medium heated by the heater before and during printing, and after printing, the printed matter can be heated and dried by the heater.
Printing was performed by changing the type of recording medium, heating conditions, and printed image in the high-gloss printing mode and the low-gloss printing mode.
The image is printed so that the color ink is on the first layer and the clear ink is on the second layer so that the clear ink print image is printed on the color ink print image, and the two layers are printed at the same time. Post-drying was performed. As for printing, two layers of color ink and clear ink were printed in one printing.

-Recording medium-
In the high-gloss printing mode, synthetic paper VJFN160 (white polypropylene film, glossiness 16 (60 ° gloss value)) manufactured by YUPO Co., Ltd. was used as the recording medium 1.
In the low-gloss printing mode, a window film GIY-0305 (transparent polyethylene terephthalate (PET) film, glossiness 159 (60 ° gloss value)) manufactured by Lintec Sign System Co., Ltd. was used as the recording medium 2.

-Heating conditions-
As for the heating conditions, in the high gloss printing mode, the heating temperatures of the heaters arranged before, during, and after printing were set to 50 ° C, 50 ° C, and 70 ° C. In the low-gloss printing mode, the heating temperatures of each heater were set to 70 ° C, 70 ° C, and 70 ° C. When the temperature of the recording medium during printing was measured, the recording medium temperature (= _High ) in the high-gloss printing mode was 49 ° C., and the recording medium temperature (= T _low ) in the low-gloss printing mode was 68 ° C.
The temperature of the recording medium during printing was measured by a digital radiation temperature sensor FT-H10 (manufactured by KEYENCE CORPORATION).
The temperature HT (° C.) of the heating means was based on the temperature of the heating means during printing.

-Printed image-
In both the high-gloss printing mode and the low-gloss printing mode, the color ink print image was a 4C composite image having an image resolution of 600 dpi × 600 dpi, a printing rate of 10% for each color, and a total of 40% for the four colors. .. Here, the 4C composite image is an image made of four colors of yellow ink, magenta ink, cyan ink, and black ink.
The clear ink print image is a full image with an image resolution of 600 dpi × 600 dpi and a print rate of 100% when printed in the high gloss print mode, and an image resolution of 600 dpi × 600 dpi when printed in the low gloss print mode. It was a halftone image with a 600 dpi printing rate of 40%.
The clear ink image was printed smaller than the 4C composite image. The 4C composite image was partially covered with a clear ink image, but was printed so that only a part of the 4C composite image without clear ink was printed.

-Print rate-
The printing rate here means the following.
Printing rate (%) = number of clear ink printing dots / (vertical resolution x horizontal resolution) x 100
(However, in the above formula, the "number of clear ink printing dots" is the number of dots actually printed with clear ink per unit area, and the "vertical resolution" and "horizontal resolution" are the resolutions per unit area, respectively. When printing clear inks in layers so that they have the same dot position, the "clear ink printing dot number" is represented by the total number of dots actually printed with clear ink per unit area.)
In both the low-gloss printing mode and the high-gloss printing mode, clear ink A was directly applied once on the 4C composite image so as to overlap at the same dot position.

(Examples 2 to 13, Comparative Examples 1 to 4)
Printed matter of Examples 2 to 13 and Comparative Examples 1 to 4 were obtained in the same manner as in Example 1 except that the printing conditions were changed to the conditions shown in Table 7 in Example 1.

Next, each printed matter of Examples 1 to 13 and Comparative Examples 1 to 4 was evaluated by the evaluation method shown below.

<Glossiness>
Measure each of the two-layer printing part on which the color ink and clear ink ink were printed and the print part on which only the color ink was printed, and set "(Glossiness of the clear ink printing part)-(Glossiness of the printing part of the color ink only). ) ”Was calculated. In the high gloss mode, the larger the value, the higher the gloss tends to be, and in the low gloss mode, the smaller the value, the lower the gloss tends to be. The results are shown in Table 8.
It was measured using a glossiness measuring device (Microtrigloss, manufactured by BYK). The 60 ° gloss value was used.

<Glossy>
"(Glossiness of the clear ink printed part)-(Glossiness of the printed part of color ink only)" of _{the printed matter printed in the high gloss mode is GH} , and "(Glossiness of the clear ink printed part) of the printed matter printed in the low gloss mode. gloss) - a (glossiness of the printed portion of only the color ink) "and G _L, and calculates the G _H -G _L, were evaluated by the following criteria. The results are shown in Table 8. The _{larger the value of GH} - _GL , the sufficient difference between high gloss and low gloss can be obtained. In addition, Δ or more is the actual usable level.
[Evaluation criteria]
⊚: _GH - _GL is 111 or more 〇: _GH - _GL is 91 or more and 110 or less Δ: _GH - _GL is 71 or more and 90 or less ×: _GH - _GL is 70 or less

<Image color unevenness>
The printed matter was visually observed and the color unevenness of the image was evaluated based on the following criteria. The results are shown in Table 8. In addition, Δ or more is the actual usable level.
[Evaluation criteria]
⊚: Color unevenness is not recognized at a distance of less than 30 cm from the image 〇: Color unevenness is not recognized at a distance of 30 cm or more and less than 1 m from the image Δ: Color unevenness is not recognized at a distance of 1 m or more and less than 3 m from the image ×: From the image Color unevenness can be recognized at a distance of 3 m or more

From the results in Table 8, Examples 1 to 13 in which _{T low} > T _high are particularly color ink and clear as compared with Comparative Example 3 in which _{T low} = T _{high and Comparative Example 4 in which T low} <T _high. Looking at the results of the difference in glossiness between the two-layer printing portion of the ink and the printing portion containing only color ink, it was found that the gloss was greatly reduced in the low-gloss printing mode and the gloss was greatly increased in the high-gloss printing mode. As a result, a sufficient difference in glossiness was obtained between high gloss and low gloss, and the glossiness was good.
Further, comparing Example 1 and Example 2, Example 1 having a D _high- D _low of 60% has higher gloss and lower gloss than Example 2 having _{a D high-} D _{low of 10%.} A sufficient difference in glossiness was obtained and the glossiness was improved.
Further, when Example 1 and Example 5 are compared, Example 1 in which the resin content in the clear ink is 8% by mass or more corresponds to Example 5 in which the resin content in the clear ink is less than 8% by mass. In comparison, a sufficient difference in glossiness was obtained between high gloss and low gloss, and the glossiness was good.
Further, comparing Example 1 and Example 9, Example 1 in which the content of the surfactant is 2% by mass or less is compared with Example 9 in which the content of the surfactant exceeds 2% by mass. It was found that in the low-gloss printing mode, a large gloss change can be obtained in the portion printed with the clear ink as compared with the portion printed with only the color ink.
Further, comparing Example 1 and Example 3, Example 1 having a T _low- T _high of 10 ° C. or higher has a higher gloss than that of Example 3 having _{a T low-} T _{high of less than 10 ° C.} With low gloss, a sufficient difference in glossiness was obtained, and the glossiness was good.
Further, in Examples 1 to 13, in which the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink is 0.08 or more and 0.20 or less, the P / R is 0.08. It was found that the color unevenness of the printed matter was superior to that of Comparative Example 1 which was less than 0.2 and Comparative Example 2 which was larger than 0.2.
Comparing Example 1, Example 7, Example 8, and Example 12, Example 1 in which the content of the cyan pigment in the cyan ink is 0.8% by mass or more and 1.5% by mass or less is cyanide. The color unevenness of the printed matter is better than that of Examples 7 and 8 in which the pigment content is more than 1.5% by mass and Example 12 in which the cyan pigment content is less than 0.8% by mass. all right.
Further, when Example 1, Example 6 and Example 11 are compared, the content of the black pigment in the black ink and the content of the magenta pigment in the magenta ink are all 2.0% by mass or more and 4.0% by mass or less. Example 1 is compared with Example 6 in which the content of the black pigment and the magenta pigment is more than 4.0% by mass, and Example 11 in which the content of the black pigment and the magenta pigment is less than 2.0% by mass. It was found that the color unevenness of the printed matter was good.

The mode of the present invention is, for example, as follows.
<1> Ink accommodating part for accommodating ink and
An ejection head that ejects ink to form a print layer,
An inkjet printing apparatus having a heating means for heating a printed matter.
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The inkjet printing device is a printing device that prints clear ink on color ink, and has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. Have and
_{When the heating means adheres the clear ink onto the color ink, the temperature of the object} to be printed in the low-gloss printing area to be printed in the low-gloss printing mode is set to Low (° C.), and the clear ink is applied onto the color ink. Assuming that the temperature of the object to be printed in the high-gloss printing area to be printed in the high-gloss printing mode at the time of adhesion is T _high (° C.), it is characterized by heating so as to satisfy the _{following equation, T low} > T _high. It is an inkjet printing device.
<2> The inkjet printing apparatus according to <1>, wherein the heating means heats so as to satisfy the following formula, T _{low −} T _{high ≧ 10 ° C.}
<3> Assuming that the glossiness of the printed matter used in the low gloss printing mode is G _low and the glossiness of the printed matter used in the high gloss printing mode is G _high , the following equation, G _low > G _high , is satisfied. The inkjet printing apparatus according to any one of <1> to <2>.
<4> The inkjet printing apparatus according to any one of <1> to <3>, wherein the content of the resin in the clear ink is 8% by mass or more.
<5> The inkjet printing apparatus according to any one of <1> to <4>, wherein the resin in the clear ink is a polyurethane resin.
<6> The inkjet printing apparatus according to any one of <1> to <5>, wherein the clear ink further contains a surfactant and the content of the surfactant is 2.0% by mass or less. ..
<7> The inkjet printing apparatus according to any one of <1> to <6>, wherein the content of the cyan pigment in the cyan ink is 0.8% by mass or more and 1.5% by mass or less.
<8> The color ink contains black ink and magenta ink, and the content of the black pigment in the black ink and the content of the magenta pigment in the magenta ink are both 2.0% by mass or more and 4.0% by mass or less. The inkjet printing apparatus according to any one of <1> to <7>.
<9> The inkjet printing apparatus according to any one of <1> to <8>, wherein the resin in the color ink is a polyurethane resin.
<10> Ink accommodating part for accommodating ink and
An ejection head that ejects ink to form a print layer,
An inkjet printing apparatus having a heating means for heating a printed matter.
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The inkjet printing device is a printing device that prints clear ink on color ink, and has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. And
_Assuming that the temperature of the heating means in the low-gloss printing mode is HT low (° C.) and the temperature of the heating means in the high-gloss printing mode is HT _high (° C.), the following equation, HT _low > HT _high , is satisfied. It is an inkjet printing apparatus characterized by heating as described above.
<11> A printing process in which ink is ejected onto a printed matter to provide a printed layer, and
A heating process that heats the printed matter to be printed,
Inkjet printing method including
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The inkjet printing method is a printing method for printing clear ink on color ink, and has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. And
_{In the heating step, the temperature of the object} to be printed in the low-gloss printing area to be printed in the low-gloss printing mode when the clear ink is adhered onto the color ink is set to Low (° C.), and the clear ink is applied onto the color ink. Assuming that the temperature of the object to be printed in the high-gloss printing area to be printed in the high-gloss printing mode at the time of adhesion is T _high (° C.), it is characterized by heating so as to satisfy the _{following equation, T low} > T _high. This is an inkjet printing method.
<12> A method for controlling gloss of a printed image, which includes a printing step of ejecting ink onto a printed matter to provide a printing layer and a heating step of heating the printed matter to be printed.
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The gloss control method for a printed image has a low gloss print mode, which is a print mode for imparting low gloss, and a high gloss print mode, which is a print mode for imparting high gloss.
When printing in the low-gloss printing mode, the heating temperature is controlled to be higher than in the case of printing in the high-gloss printing mode.
When printing in the high-gloss printing mode, the glossiness control method for a printed image is characterized in that the heating temperature is controlled to be lower than that in the case of printing in the low-gloss printing mode.

400 Image forming device 401 Exterior 401c cover 404 Cartridge holder 410, 410k, 410c, 410m, 410y Main tank 411 Ink storage unit 413 Ink discharge port 414 Storage container case 420 Mechanical unit 434 Discharge head 436 Supply tube L Ink storage container

Japanese Unexamined Patent Publication No. 2015-3397 Japanese Unexamined Patent Publication No. 2016-203626 Japanese Unexamined Patent Publication No. 2012-232529 Japanese Unexamined Patent Publication No. 2014-205767

Claims (12)

An ink storage unit that stores ink and
An ejection head that ejects ink to form a print layer,
An inkjet printing apparatus having a heating means for heating a printed matter.
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The inkjet printing device is a printing device that prints clear ink on color ink, and has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. Have and
_{When the heating means adheres the clear ink onto the color ink, the temperature of the object} to be printed in the low-gloss printing area to be printed in the low-gloss printing mode is set to Low (° C.), and the clear ink is applied onto the color ink. Assuming that the temperature of the object to be printed in the high-gloss printing area to be printed in the high-gloss printing mode at the time of adhesion is T _high (° C.), it is characterized by heating so as to satisfy the _{following equation, T low} > T _high. Ink printing equipment. The inkjet printing apparatus according to claim 1, wherein the heating means heats so as to satisfy the following formula, T _{low −} T _{high ≧ 10 ° C.} Assuming that the glossiness of the printed matter used in the low-gloss printing mode is G _low and the glossiness of the printed matter used in the high-gloss printing mode is G _high , the following equation, G _low > G _high , is satisfied. 2. The inkjet printing apparatus according to any one of 2. The inkjet printing apparatus according to any one of claims 1 to 3, wherein the content of the resin in the clear ink is 8% by mass or more. The inkjet printing apparatus according to any one of claims 1 to 4, wherein the resin in the clear ink is a polyurethane resin. The inkjet printing apparatus according to any one of claims 1 to 5, wherein the clear ink further contains a surfactant, and the content of the surfactant is 2.0% by mass or less. The inkjet printing apparatus according to any one of claims 1 to 6, wherein the content of the cyan pigment in the cyan ink is 0.8% by mass or more and 1.5% by mass or less. The claim that the color ink contains black ink and magenta ink, and the content of the black pigment in the black ink and the content of the magenta pigment in the magenta ink are both 2.0% by mass or more and 4.0% by mass or less. The inkjet printing apparatus according to any one of 1 to 7. The inkjet printing apparatus according to any one of claims 1 to 8, wherein the resin in the color ink is a polyurethane resin. An ink storage unit that stores ink and
An ejection head that ejects ink to form a print layer,
An inkjet printing apparatus having a heating means for heating a printed matter.
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The inkjet printing device is a printing device that prints clear ink on color ink, and has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. And
_Assuming that the temperature of the heating means in the low-gloss printing mode is HT low (° C.) and the temperature of the heating means in the high-gloss printing mode is HT _high (° C.), the following equation, HT _low > HT _high , is satisfied. An inkjet printing apparatus characterized in that it is heated in such a manner. A printing process in which ink is ejected onto a printed matter to provide a printed layer,
A heating process that heats the printed matter to be printed,
Inkjet printing method including
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The inkjet printing method is a printing method for printing clear ink on color ink, and has a low-gloss printing mode, which is a printing mode for imparting low gloss, and a high-gloss printing mode, which is a printing mode for imparting high gloss. And
_{In the heating step, the temperature of the object} to be printed in the low-gloss printing area to be printed in the low-gloss printing mode when the clear ink is adhered onto the color ink is set to Low (° C.), and the clear ink is applied onto the color ink. Assuming that the temperature of the object to be printed in the high-gloss printing area to be printed in the high-gloss printing mode at the time of adhesion is T _high (° C.), it is characterized by heating so as to satisfy the _{following equation, T low} > T _high. Ink printing method. A method for controlling gloss of a printed image, which includes a printing step of ejecting ink to a printed matter to provide a printing layer and a heating step of heating the printed matter to be printed.
The ink has a clear ink containing resin and water, and a color ink containing resin, pigment, and water.
The color ink contains cyan ink, and the mass ratio (P / R) of the cyan pigment content P to the resin content R in the cyan ink satisfies 0.08 or more and 0.20 or less.
The gloss control method for a printed image has a low gloss print mode, which is a print mode for imparting low gloss, and a high gloss print mode, which is a print mode for imparting high gloss.
When printing in the low-gloss printing mode, the heating temperature is controlled to be higher than in the case of printing in the high-gloss printing mode.
A method for controlling the glossiness of a printed image, which comprises controlling the heating temperature to be lower when printing in the high gloss printing mode as compared with the case of printing in the low gloss printing mode.

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