JP2015085568A - Image recording method and image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording method for obtaining an image having satisfactory image quality and sufficiently securing abrasion resistance by securing solid uniformity without causing bleeding by using a heater and aqueous ink during printing when printed on a non-porous recording medium.SOLUTION: There is provided an image recording method of creating an image by adhering ink on a non-porous recording medium by discharging ink from a nozzle, the method comprising: a printing step of creating an image by controlling the surface temperature on the recording surface side of the non-porous recording medium at 40°C or more and 60°C or less; and a step of drying and fixing an unfixed image by heating, where the ink contains at least water, a water-soluble organic solvent, a coloring agent and resin fine particles, the water-soluble organic solvent contains no solvent having a boiling point of more than 250°C and in the printing step, the surface temperature of the non-porous recording medium is reduced according to the increase in the number of printing scans.

Description

  The present invention relates to an ink jet recording method using an aqueous ink jet ink that is optimal for recording on a non-porous recording medium, and an ink jet recorded matter.

Ink jet printers have advantages such as low noise, low running cost, and easy color printing, and are therefore widely used as digital signal output devices in general households.
In recent years, it is used not only for home use but also for industrial use such as a display, a poster, and a bulletin board. However, for industrial use, porous recording media have problems with durability such as light resistance, water resistance, and abrasion resistance, so non-porous recording media such as plastic films are used. It has been developed. For example, solvent-based ink-jet inks using an organic solvent as a vehicle and UV-curable ink-jet inks mainly composed of a polymerizable monomer have been widely used.

  However, solvent-based ink-jet inks are not preferable from the viewpoint of environmental burden because they evaporate a large amount of solvent into the atmosphere. The ultraviolet curable ink-jet ink may have skin sensitization depending on the monomer used, and the application field is limited because an expensive ultraviolet irradiation device needs to be incorporated in the printer body.

  Against this background, recently, an ink-jet ink that can be directly printed on a non-porous recording medium has been developed with a water-based ink-jet ink that has been used as a home-use ink-jet ink, and has a low environmental impact. Yes. Examples of such attempts include the techniques described in Patent Document 1 and Patent Document 2, for example.

However, it has been pointed out that these water-based inks are generally inferior in image quality as compared with solvent-based inkjet inks.
First, the ink does not penetrate into the base material of the non-porous recording medium, so the ink on the base material must be dried immediately, but with water itself, which is the main solvent of the water-based ink, and additives. A certain water-soluble organic solvent deteriorates the drying property and easily causes poor drying. For this reason, a heater for assisting drying is used in combination. As the heater, a post-printing heater that completely dries the ink, an in-printing heater that can be dried immediately after printing, and a pre-printing heater are used in combination.

  When poor drying occurs, the fixing property after drying deteriorates and the image is peeled off by rubbing. Therefore, it is necessary to dry the moisture and solvent sufficiently with a heater after printing. In order to suppress energy used for drying an image, it is required to improve the drying property of the ink. However, when the drying property of the ink is increased, the drying is promoted even at the meniscus of the head, so that it tends to cause ejection failure.

  Since non-porous recording media do not undergo osmotic drying, unlike porous recording media, osmotic drying immediately after printing cannot be obtained. For this reason, drying immediately after printing is promoted using a heater during printing so as to obtain drying immediately after printing (for example, Patent Document 3). If the heating value of this heater is weak, poor drying immediately after printing is caused, and image quality deterioration such as dot fusion due to drying delay occurs. On the other hand, if the amount of heat generated by the heater is too strong, the radiation heat to the nozzle portion of the head is too great, and the meniscus is dried, causing a discharge failure. In addition, the faster the ink drying speed, the lower the temperature that can be fixed, which saves energy. However, if the drying speed becomes too high due to the heater during printing, the dot spread of the image is small, resulting in a decrease in solid uniformity and image density. End up. These phenomena depend on both the drying characteristics of the ink and the drying power of the heater, and vary depending on the print mode and the ink type. Therefore, in order to obtain a good printed matter, the user actually changes the setting of the print mode and the heater temperature and repeatedly prints to obtain a desired image.

  The present invention obtains an image with good image quality that does not cause bleeding using a heater and water-based ink during printing when printed on a non-porous recording medium, and ensures solid uniformity and sufficient scratch resistance. The purpose is to provide a recording method.

  The object of the present invention is to provide a surface temperature on the recording surface side of the nonporous recording medium in the image recording method of forming an image by adhering ink onto the nonporous recording medium by ejecting ink from a nozzle. A printing process for forming an image by adhering the ink within a range of 40 ° C. or more and 60 ° C. or less, and a drying process for heating and fixing an image that has not been fixed; Contains water, a water-soluble organic solvent, a colorant, and resin fine particles, and the water-soluble organic solvent does not contain a solvent having a boiling point exceeding 250 ° C. In the printing process, according to an increase in the number of print scans. An image recording method characterized by lowering the surface temperature of the non-porous recording medium.

  According to the present invention, when printing on a non-porous recording medium, an image with good image quality that does not cause bleeding using a heater and water-based ink during printing, ensures solid uniformity, and sufficiently ensures scratching. Can be provided.

It is the schematic which shows an ink cartridge. It is a modification of the ink cartridge shown in FIG. It is the schematic showing an example of the image recording device of this invention. It is the schematic which looked at the carriage part in FIG. 3 from the upper surface side. It is a whole block explanatory drawing showing the outline | summary of an example of the control part of an image recording device. It is a graph showing the relationship between the evaporation rate about each ink prepared in the Example, and elapsed time. It is a graph showing the relationship between the number of scans and the optimum temperature for the ink sets 1 and 3 prepared in the examples.

  The ink used in the present invention contains at least water, a water-soluble organic solvent, a pigment, and resin fine particles. By using water as a solvent, the amount of organic matter generated at the time of drying can be reduced, and VOC can be reduced as compared with ether-based solvent printing used for printing on non-porous recording media. Moreover, the heater calorie | heat amount of a drying process can be reduced by not containing the water-soluble organic solvent whose boiling point exceeds 250 degreeC. Moreover, since the amount of the organic solvent remaining after drying can be reduced, the scratch resistance and solvent resistance of the ink coating film can be improved.

  By containing resin fine particles in the ink, it can function as a binder for fixing a pigment to a non-porous recording medium. Moreover, the surface of an ink coating film can be smoothed and glossiness can be provided.

As the drying characteristics of the ink, it is preferable that the mass change rate up to 25% by mass change rate of the ink at an ink exposure surface area of 5 mg / mm ² , 25 ° C. and 10% RH or less is 0.2% by mass / min or more. Thereby, when printing is performed in the range of 40 to 60 ° C. on the recording surface side of the non-porous recording medium, a good image without color bleeding or dot fusion can be formed.
The ink exposure surface area is an area where the ink is exposed to the space, and is a surface area of the gas-liquid interface between the ink and the atmosphere when the drying characteristics are evaluated. Since the drying proceeds from this gas-liquid interface, the drying speed varies depending on the area of the interface. Therefore, the drying speed was measured at a constant surface area and determined as the drying characteristics.

  In addition, by reducing the surface temperature according to the increase in the number of print scans, excessive drying immediately after printing can be suppressed, and the dot diameter can be increased, the resulting solid uniformity can be improved, and the image density can be improved. I can do it.

  Furthermore, when 50% by mass or more of the water-soluble organic solvent used in the ink has a boiling point of 200 ° C. or less, it can be further improved, and the amount of energy required for drying due to improvement in coating film characteristics and reduction in heater temperature Reduction is possible. As such a water-soluble organic solvent, for example, by using an ink containing 2,3-butanediol, the affinity of the ink with water is improved and the moisture retention is improved. For this reason, it is possible to suppress drying of the ink in the ink jet head, and it is possible to suppress nozzle defects such as ejection bending and non-ejection.

  By using such an ink and a drying method, it is possible to propose a recording method that forms a good image on a non-porous recording medium with low energy and low energy. Furthermore, by providing an image recording apparatus using this recording method, it is possible to provide a favorable image quality for a non-porous recording medium with a low load on the environment.

A water-soluble organic solvent is blended with the water-based ink for ink jet (hereinafter sometimes referred to as ink) in order to prevent drying on the nozzle surface of the ink and to ensure the wettability of the ink with respect to the recording medium. Since water-soluble organic solvents generally have a boiling point higher than water and are difficult to dry, it is necessary to use a water-soluble organic solvent having a relatively low boiling point in order to obtain the drying property required by the present invention.
In addition, since water-based ink is composed of a solvent having a high boiling point such as water, if printing is performed on a non-porous recording medium in which osmotic drying cannot be obtained, drying time is required and image distortion occurs. In view of this, heating with a heater or the like increases the drying speed of the water-based ink to ensure printability with respect to the non-porous recording medium.

In the inkjet image formation of water-based ink on a non-porous recording medium, ink drying starts from the time when ink is ejected from the head. For this reason, the viscosity of the ink droplets which have landed on the non-porous recording medium and then dried and landed increases, and after the positions are determined as dots on the non-porous recording medium, they are completely dried and fixed.
If drying immediately after landing is insufficient, the ink that has landed for several minutes will have fluidity, and when the landing dots are adjacent, the surface tension of the liquid will be superior to the fluidity of the ink and fused to form a dot shape. Change or movement from the landing position occurs, and the recorded image is violently disturbed. In order to suppress such a phenomenon, drying immediately after printing is important in ink-jet image formation of water-based ink on a non-porous recording medium. By providing a heater during printing that promotes drying simultaneously with printing, the recorded image can be printed. Disturbance can be suppressed.

  The output of the heater during printing is desirably an output at which the surface temperature of the non-porous recording medium is 40 to 60 ° C. If the surface temperature of the non-porous recording medium is 40 ° C. or higher, drying of the ink is promoted during printing, and the disorder of the recorded image is suppressed. In addition, when the surface temperature becomes high, the drying of the image is further promoted, but the ejection failure due to the inkjet head being heated by the radiant heat from the surface of the non-porous recording medium and the drying from the nozzle meniscus portion being promoted. Is likely to be caused. In addition, in order to suppress ejection failure, the number of ink discards and head cleanings called purging increases, and the consumption of ink that is not used for printing increases. Therefore, by maintaining the output of the heater during printing at a surface temperature of the nonporous recording medium of 60 ° C. or less, drying of the ink on the nonporous recording medium can be promoted while suppressing ejection failure of the head.

  When an image is output by the ink jet apparatus, the image resolution, the printing speed, and the ink adhesion amount vary greatly depending on the printing mode. The influence of the heater during printing greatly contributes to the printing speed, and the cumulative heat quantity during printing increases as the printing speed is slower. Since ink drying progresses as it receives a larger amount of heat by the heater during printing, the liquid volume of the ink dots before entering the drying process becomes smaller, and the dot diameter becomes smaller.

  Many non-porous recording media have a hydrophobic surface compared to porous recording media such as paper. In order to allow water-based ink to wet and spread on non-porous recording media, it is necessary to provide wettability with a surfactant. It has become. However, since the wettability of the surfactant is exhibited by causing the orientation of the surfactant to the interface, a time of 1 second or more is required for sufficient wetting and spreading. If the amount of heat of the heater during printing is too large, drying is promoted too much, and the toner is dried and fixed before it spreads to a sufficient dot diameter, so an ideal dot diameter cannot be obtained. Therefore, the image cannot be sufficiently filled with dots, resulting in insufficient solid uniformity and a decrease in density.

  Therefore, in the printing mode with a slow printing speed, the temperature of the heater during printing is changed according to the number of printing scans to control the surface temperature of the non-porous recording medium. That is, by reducing the surface temperature of the non-porous recording medium as the number of passes increases, excessive dot tightening can be suppressed and good images can be obtained in various printing modes. The temperature of the heater during printing is, for example, 55 ° C. to 60 ° C. when the number of scans is 1 to 5 times, 50 ° C. to 58 ° C. when the number of scans is 6 to 10 times, and 11 to 20 times. May be set to 45 ° C. to 55 ° C., and in the case of 21 to 30 times, 40 ° C. to 50 ° C. Note that the optimum value of the relationship between the number of print scans and the surface temperature of the non-porous recording medium varies depending on the ink formulation, and the above range is not necessarily optimum.

  In addition, drying with a heater during printing is such that the mobility of ink with respect to dot fusion is suppressed, and the ink easily moves when it comes into contact with the image. Therefore, it is necessary to completely dry and fix the ink. In the ink in this state, most of the water is evaporated, and the water-soluble organic solvent, the colorant, and the resin fine particles contained in the ink remain. Although it is necessary to evaporate the water-soluble organic solvent from this ink, many water-soluble organic solvents have a boiling point higher than that of water, and in order to promote drying, a heating device with a stronger output than the heater during printing is required. Necessary. In the image recording method of the present invention, the step of promoting the complete drying of the ink in this way is the drying step.

In the drying step, heating is performed not only to evaporate the water-soluble organic solvent but also to promote image film formation of the contained resin particles. In general, resin particles have a temperature at which an image film can be formed (minimum image film temperature). Below that temperature, the resin particles cannot be fused together and cannot be formed because they exist as individual particles. When the temperature is equal to or higher than the minimum image film temperature, the resin particles are fused to form a single resin film, so that a film can be formed. Since the fixability of the pigment in the ink is low with respect to the nonporous recording medium, the resin forms a film and the pigment is fixed to the nonporous recording medium to fix the image.
Increasing the output of the heater in the drying process can increase the drying speed and increase the productivity, but if the film formation of resin fine particles becomes too fast, drying unevenness tends to occur in the film thickness direction, resulting in sufficiently uniform coating. The film cannot be formed, and the film strength and glossiness are inferior.

≪About ink≫
<Water-soluble organic solvent>
The water-soluble organic solvent used in the present invention is preferably 50% by mass or more of a diol compound. In the present invention, the diol compound refers to a compound having two OH groups in the chemical structural formula. These diol compounds have a higher moisture retention than compounds containing no OH group or compounds containing only one OH group, and greatly contribute to ink ejection reliability. In the case of a compound containing three or more OH groups, the intermolecular force becomes too strong, so that many of the boiling points are extremely high, and the drying property may be greatly impaired.

  Examples of the diol compound include the following compounds. Ethylene glycol (bp 196 ° C), propylene glycol (bp 188 ° C), 1,2-butanediol (bp194 ° C), 2,3-butanediol (bp183 ° C), 2-methyl-2,4-pentanediol (bp 198 ° C) , Diethylene glycol (bp 244 ° C.), triethylene glycol (bp 287 ° C.), dipropylene glycol (bp 230 ° C.), 1,3-propanediol (bp 214 ° C.), 1,3-butanediol (bp 203 ° C.), 1,4-butane Diol (bp 230 ° C.), 2,2-dimethyl-1,3-propanediol (bp 208 ° C.), 2-methyl-1,3-propanediol (bp 213 ° C.), 1,2-pentanediol (bp 206 ° C.), 2 , 4-Pentanediol (bp 201 ° C.), 1,5-pentanedio (Bp 242 ° C), 1,6-hexanediol (bp 250 ° C), 2-ethyl-1,3-hexanediol (bp243 ° C), 1,2-hexanediol (bp224 ° C), 2,5-hexanediol ( bp 217 ° C).

  Moreover, it is preferable that 50 mass% or more of the water-soluble organic solvent used by this invention has a boiling point of 200 degrees C or less. Examples thereof include the following compounds. Ethylene glycol (bp 196 ° C), propylene glycol (bp 188 ° C), 1,2-butanediol (bp194 ° C), 2,3-butanediol (bp183 ° C), 2-methyl-2,4-pentanediol (bp 198 ° C) , Dipropylene glycol monomethyl ether (bp 190 ° C.), propylene glycol n-butyl ether (bp 171 ° C.), propylene glycol-t-butyl ether (bp 153 ° C.), diethylene glycol methyl ether (bp 194 ° C.), ethylene glycol-n-propyl ether (bp 150 ° C.) , Ethylene glycol-n-butyl ether (bp 171 ° C.) and the like. These water-soluble organic solvents may be used alone or in combination of two or more.

  As the water-soluble organic solvent having a boiling point of 200 ° C. or lower, 2,3-butanediol is preferably used. 2,3-butanediol has good compatibility with many water-dispersible resins, particularly good compatibility with polycarbonate-based urethane resin fine particles, and an ink having more excellent film forming properties can be obtained. The ink using these water-soluble organic solvents improves the gloss of the coating film.

In addition, for the purpose of controlling ink physical properties, preventing drying, improving dissolution stability, and the like, a water-soluble organic solvent other than the water-soluble organic solvent having a boiling point of 200 ° C. or lower may be added as necessary.
Examples thereof include the following compounds. Diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1, 3-propanediol, 1,2-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-hexanediol Polyhydric alcohols such as 2,5-hexanediol, dipropylene glycol-n-propyl ether, tripropylene glycol methyl ether, tripropylene glycol-n-propyl ether, propylene glycol phenyl ether, triethylene glycol methyl ether, triethylene glycol Ethylene glycol Lumpur methyl ether, triethylene glycol ethyl ether, diethylene glycol -n- hexyl ether, polyhydric alcohol alkyl ethers such as ethylene glycol phenyl ether, 2-pyrrolidone, and a nitrogen-containing heterocyclic compounds such as N- methylpyrrolidinone.
It should be noted that it is effective to not include a water-soluble organic solvent having a boiling point exceeding 250 ° C., since the drying property is further improved.

<Colorant>
As the colorant, pigments and poorly water-soluble dyes can be preferably used. Examples of the poorly water-soluble dye include oil-soluble dyes.
In the case where the colorant is a pigment, the following first form and second form are preferable.
(1) In the first form, the colorant has at least one hydrophilic group on the surface and exhibits water dispersibility in the absence of a dispersant (hereinafter referred to as “self-dispersing pigment”). A pigment dispersion containing
(2) In the second embodiment, the colorant contains a polymer emulsion (an aqueous dispersion of polymer fine particles containing a colorant) in which a polymer fine particle contains a water-insoluble or poorly water-soluble colorant.

  As the pigment, an organic pigment or an inorganic pigment can be used. In addition, although you may contain dye simultaneously for the purpose of color tone adjustment, it is possible to use within the range which does not degrade a weather resistance.

Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is particularly preferable.
In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

Examples of the organic pigment include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable.
Examples of the azo pigment include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments.

Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofullerone pigments.
Examples of the dye chelate include basic dye chelate and acid dye chelate.

  There is no restriction | limiting in particular as a color of the said colorant, According to the objective, it can select suitably, For example, the colorant for black, the colorant for color, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

As the black colorant, for example, the following pigments can be preferably used. Carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, metals such as copper, iron (CI pigment black 11), titanium oxide, aniline black (C Organic pigments such as I. Pigment Black 1).
Examples of the commercially available carbon black include the following. Carbon black available from Cabot Corporation under the trademarks Regal (R), Black Pearls (R), Elftex (R), Monarch (R), Mogul (R), Vulcan (R), and the like.

Examples of the colorant for color include the following. C. 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, 128, 138, 150, 151, 153, 155, 183, 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, 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, 185, 190, 193, 209, 219, 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 (phthalocyanine blue), 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63; I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
Other suitable color pigments are described in The Color Index, 3rd edition (The Society of Dyers and Colorists, 1982).

<< colorant of the first form >>
The self-dispersing pigment of the first form is surface-modified so that at least one hydrophilic group is bonded to the surface of the pigment directly or through another atomic group. In the surface modification, a specific functional group (a functional group such as a sulfone group or a carboxyl group) is chemically bonded to the surface of the pigment, or at least one of hypohalous acid and a salt thereof is used. A method such as wet oxidation is used. Among these, a form in which a carboxyl group is bonded to the surface of the pigment and dispersed in water is particularly preferable.

Thus, the pigment is surface-modified and the carboxyl group is bonded, so that not only the dispersion stability is improved, but also high-quality printing quality is obtained, and the water resistance of the recording medium after printing is improved. More improved.
The ink containing the self-dispersing pigment of the first form is excellent in redispersibility after drying. For this reason, printing is suspended for a long period of time, and even when ink moisture near the ink jet head nozzles evaporates, clogging does not occur, and good printing can be easily performed with a simple cleaning operation.

The volume average particle diameter (D50) of the self-dispersing pigment is preferably 0.01 μm to 0.16 μm in the ink.
Examples of the specific functional group in the self-dispersing pigment include the following anionic functional groups. _{-COOM, -SO 3 M, -PO 3} HM, -PO 3 M 2, -CONM 2, -SO 3 NM 2, -NH-C 6 H 4 -COOM, -NH-C 6 H 4 -SO 3 M , —NH—C ₆ H ₄ —PO ₃ HM, —NH—C ₆ H ₄ —PO ₃ M ₂ , —NH—C ₆ H ₄ —CONM ₂ , —NH—C ₆ H ₄ —SO ₃ NM ₂ ( However, M represents a hydrogen atom, an alkali metal, quaternary ammonium or organic ammonium, and preferably a quaternary ammonium.
Among _{these, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -SO 2 NH 2, -SO 2 NHCOR preferably, -COOM, -SO ₃ M is bonded to the surface of a color pigment It is particularly preferable to use the same.

  “M” in the functional group includes, for example, lithium, sodium, potassium and the like as an alkali metal. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium.

  Examples of the method for obtaining the anionically charged color pigment include a method for introducing —COONa into the surface of the color pigment, for example, a method for oxidizing a color pigment with sodium hypochlorite, a method for sulfonation, a diazonium salt The method of making this react is mentioned.

  As the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, and a quaternary ammonium group listed below is more preferable.

Specific examples of the quaternary ammonium ion include the following. Tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, benzyltriethylammonium ion, benzyltriethylammonium ion, tetrahexylammonium ion and the like.
Among these, tetraethylammonium ion, tetrabutylammonium ion, and benzyltrimethylammonium ion are preferable, and tetrabutylammonium ion is particularly preferable.

Examples of the anionic functional group include anionic polar groups such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, an amide group, and a sulfonamide group. Among these, a carboxylic acid group and a p-aminobenzoic acid group are preferable.
The anionic functional group can be bonded to the surface of the pigment particle, for example, according to the method described in the following document. Japanese Patent No. 4697757, Japanese Patent Publication No. 2003-513137, International Publication No. 97/48769 Pamphlet, Japanese Patent Application Laid-Open No. 10-110129, Japanese Patent Application Laid-Open No. 11-246807, Japanese Patent Application Laid-Open No. 11-57458, Japanese Patent Application Laid-Open No. Hei 11 No. 189739, JP-A No. 11-323232, JP-A No. 2000-265094, and the like.

The ink used in the image recording method of the present invention preferably uses a water-dispersible colorant having the anionic functional group and the quaternary ammonium ion. These water-dispersible colorants exhibit affinity even in water-rich inks and organic solvent-rich inks from which water has evaporated, and can stably maintain the dispersion of the water-dispersible colorant.
There is no restriction | limiting in particular as a method of manufacturing the cationic self-dispersion type pigment to which the said hydrophilic group was couple | bonded, According to the objective, it can select suitably. For example, as a method for bonding an N-ethylpyridyl group represented by the following structural formula, a method of treating carbon black with 3-amino-N-ethylpyridinium bromide can be mentioned.

The hydrophilic group may be bonded to the surface of carbon black via another atomic group. Examples of other atomic groups include an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent.
Specific examples of the case where the hydrophilic group described above is bonded to the surface of carbon black via another atomic group include the following examples. -C ₂ H ₄ COOM (provided that, M represents an alkali metal or quaternary ammonium), - PhSO ₃ M (however, .M Ph is representative of a phenyl group, an alkali metal or quaternary ammonium _{represented), - C 5 H 10 NH} 3 + and the like.

<< Another aspect in the first embodiment >>
Moreover, as another aspect in the first embodiment, a modified pigment modified with either a geminal bisphosphonic acid group or a geminal bisphosphonic acid group is preferable. Examples of such a modified pigment include modified pigments modified with a group represented by any one of the following structural formulas (1), (2), (3), and (4).

In the structural formula (3), X ⁺ represents Li ⁺ , K ⁺ , Na ⁺ , NH ₄ ⁺ , N (CH ₃ ) ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺ , N (C ₃ H _{7) 4} ⁺ and N (C ₄ H _{9) 4} ⁺ represents any.

In the structural formula (4), X ⁺ represents Li ⁺ , K ⁺ , Na ⁺ , NH ₄ ⁺ , N (CH ₃ ) ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺ , N (C ₃ H _{7) 4} ⁺ and N (C ₄ H _{9) 4} ⁺ represents any.

Next, the surface modification of the pigment will be described in detail.
The dispersion containing the modified pigment was prepared using one of the following general procedures.
In the method, the compound represented by the following formula (I) and the following formula (II) is reacted with the pigment, and the phosphonic acid group is substituted with an alkali metal and organic ammonium in order to further improve the dispersibility in water. preferable.

[Compound of Formula (I)]

[Compound of Formula (II)]

[Pigment surface modification treatment]
-Method A-
Carbon black (20 g), the compound of formula (I) or 20 mmol of the compound of formula (II), and 200 mL of ion-exchange high purity water are mixed in a Silverson mixer (6,000 rpm) in a room temperature environment. If the pH of the resulting slurry is higher than 4, 20 mmol of nitric acid is added. After 30 minutes, sodium nitrite (20 mmol) dissolved in a small amount of ion-exchanged high purity water is slowly added to the above mixture. Further, the mixture is heated to 60 ° C. with stirring and reacted for 1 hour. A modified pigment obtained by adding the compound of formula (I) or the compound of formula (II) to carbon black can be produced.

  Subsequently, the modified pigment dispersion is obtained after 30 minutes by adjusting the pH to 10 with an aqueous NaOH solution. Ultrafiltration using a dialysis membrane is performed using a dispersion containing a pigment bound to at least one geminal bisphosphonic acid group or geminal bisphosphonic acid sodium salt, and ion-exchanged high-purity water, followed by ultrasonic dispersion and solidification. A modified pigment dispersion having a concentrated content is obtained.

-Method B-
A ProcessAll 4HV mixer (4 L) is charged with 500 g of dry carbon black, 1 L of ion-exchange high purity water, and 1 mol of the compound of formula (I) or the compound of formula (II). The mixture is then mixed vigorously at 300 rpm while warming to 60 ° C. for 10 minutes. 20% by weight aqueous sodium nitrite solution [1 molar equivalent based on the compound of formula (I) or the compound of formula (II)] is added to this over 15 minutes. The mixture was stirred for 3 hours while heating to 60 ° C.

  The reaction product was taken out while being diluted with 750 mL of ion-exchange high-purity water, ultrafiltration using a dialysis membrane was performed using the obtained modified pigment dispersion and ion-exchange high-purity water, and further ultrasonic dispersion was performed to obtain a solid content. A concentrated modified pigment dispersion is obtained. Furthermore, when there are many coarse particles, it is preferable to remove them using a centrifuge or the like. For each modified pigment dispersion, the sodium ion content is measured with an ion meter. Further, the total amount of phosphorus is measured by elemental analysis.

Further, the volume average particle diameter (D50) of the modified pigment in the dispersion is measured using a Microtrac (registered trademark) particle size distribution measuring device. The volume average particle size (D50) of the modified pigment dispersion is preferably 0.01 μm to 0.16 μm in the ink.
An ink containing a surface-modified pigment dispersion bonded to at least one geminal bisphosphonic acid group or geminal bisphosphonic acid sodium salt is excellent in redispersibility after drying. For this reason, printing is suspended for a long period of time, and even when ink moisture near the ink jet head nozzles evaporates, clogging does not occur, and good printing can be easily performed with a simple cleaning operation.
Furthermore, the ink is highly stable even when stored over time, the ink is suppressed in viscosity increase when water evaporates, and the ink in the ink head maintenance device is excellent in ink fixing and ejection reliability. became.

<< Colorant of Second Form >>
As the colorant of the second form, it is preferable to use a polymer emulsion in which a pigment is contained in polymer fine particles in addition to the pigment. The polymer emulsion in which the pigment is contained in the polymer fine particles is one in which the pigment is encapsulated in the polymer fine particles, or the pigment is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary that all the pigments are encapsulated or adsorbed, and the pigments may be dispersed in the emulsion as long as the effects of the present invention are not impaired.

  Examples of the polymer forming the polymer emulsion (polymer in the polymer fine particles) include vinyl polymers, polyester polymers, polyurethane polymers, and the like. Polymers particularly preferably used are vinyl polymers and polyester polymers, and polymers disclosed in JP-A Nos. 2000-53897 and 2001-139849 can be preferably used.

In the second embodiment, a composite pigment obtained by coating general organic pigment or inorganic pigment particles with an organic pigment or carbon black can be preferably used.
The composite pigment can be produced by a method of depositing an organic pigment in the presence of inorganic pigment particles, a mechanochemical method of mechanically mixing and grinding an inorganic pigment and an organic pigment, or the like. Further, if necessary, an adhesive layer between the inorganic pigment and the organic pigment can be improved by providing a layer of an organosilane compound formed from polysiloxane and alkylsilane between the inorganic pigment and the organic pigment.
The organic pigment and the inorganic pigment can be appropriately selected from those described above.

The mass ratio between the inorganic pigment particles and the organic pigment or carbon black as a colorant is preferably 3: 1 to 1: 3, and more preferably 3: 2 to 1: 2. When the amount of the coloring material is small, the color developability and coloring power may be lowered, and when the amount of the coloring material is large, the transparency and the color tone may be deteriorated.
As such colorant particles obtained by coating inorganic pigment particles with an organic pigment or carbon black, the following can be suitably used from the viewpoint that the primary average particle diameter is small. Silica / carbon black composite material manufactured by Toda Kogyo Co., Ltd., silica / phthalocyanine PB15: 3 composite material, silica / disazo yellow composite material, silica / quinacridone PR122 composite material, and the like.

Here, when inorganic pigment particles having a primary particle size of 20 nm are coated with an equal amount of organic pigment, the primary particle size of the pigment is about 25 nm. If a primary dispersant can be dispersed using a suitable dispersant for this, a very fine pigment-dispersed ink having a dispersed particle diameter of 25 nm can be produced.
In the composite pigment, not only the organic pigment on the surface contributes to the dispersion, but also the properties of the inorganic pigment at the center appear through the thin layer of organic pigment with a thickness of about 2.5 nm, so both are dispersed and stabilized at the same time The selection of pigment dispersants that can be made is also important.

<< Colorants in other forms >>
Examples of the colorant in the other form include a pigment dispersion containing a pigment, a pigment dispersant, and a polymer dispersion stabilizer.
The polymer dispersion stabilizer is composed of an α-olefin-maleic anhydride copolymer, a styrene- (meth) acrylic copolymer, a water-soluble polyurethane resin and a water-soluble polyester resin represented by the following general formula (A). At least one selected.

However, in said general formula (A), R represents a C6-C30, Preferably 12-22, More preferably, it represents an 18-22 alkyl group. N represents an integer of 1 or more, and an integer of 20 to 100 is preferable.

  The α-olefin-maleic anhydride copolymer represented by the general formula (A) can also be synthesized using a mixture of olefins containing olefins having different carbon numbers as raw materials. In that case, the R part is a copolymer in which alkyl groups having different carbon numbers are randomly introduced into the polymer chain.

  In the present invention, not only an α-olefin-maleic anhydride copolymer in which an alkyl group having a uniform R carbon number is introduced into a polymer chain, but also an alkyl having a different R carbon number as described above. Those in which groups are randomly introduced into the polymer chain can also be used. That is, an α-olefin-maleic anhydride copolymer in which alkyl groups having different carbon numbers for R are randomly introduced into a polymer chain is converted into an α-olefin-maleic anhydride represented by the general formula (A). It can also be used as a copolymer.

  The α-olefin-maleic anhydride copolymer represented by the general formula (A) preferably has a weight average molecular weight of 5,000 to 20,000. Here, the weight average molecular weight of the α-olefin-maleic anhydride copolymer can be measured as follows.

(Measurement of weight average molecular weight)
The average molecular weight of the copolymer can be measured using a GPC (gel permeation chromatograph) analysis system.
First, a copolymer is dissolved in the same tetrahydrofuran as the eluent, and KF806L (for THF) is used as a GPC column. In addition, three types of polystyrene having different molecular weights (molecular weights 1,000, 2,400, 8,500) whose molecular weights are known are measured as molecular weight standard substances, and a calibration curve is created.
Next, the copolymer is subjected to GPC measurement, and the weight average molecular weight is calculated from the resulting SEC chromatogram, the differential molecular weight distribution curve and the graph reflecting the calibration curve obtained from the molecular weight standard substance.

  The α-olefin-maleic anhydride copolymer, styrene- (meth) acrylic copolymer, water-soluble polyurethane resin and water-soluble polyester resin represented by the general formula (A) are solid at room temperature, It is almost insoluble. However, the dispersion stabilizer is used when dissolved in an alkali solution or an aqueous alkali solution equal to or more than the acid value of the copolymer and the resin (preferably 1.0 to 1.5 times the acid value). As an effect.

  Moreover, in order to melt | dissolve the said copolymer and the said resin with an alkali solution or aqueous alkali solution, it can melt | dissolve easily by heating and stirring. However, when the olefin chain in the α-olefin-maleic anhydride copolymer is long, it is relatively difficult to dissolve, and insoluble matter may remain. However, if the insoluble matter is removed with an appropriate filter or the like, the dispersion can be stabilized. The effect as an agent is not impaired.

  Examples of the base in the alkali solution or the aqueous alkali solution include the following. Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide; basic substances such as ammonia, triethylamine, morpholine; triethanolamine, diethanolamine, N-methyldiethanolamine, 2-amino-2-ethyl- Alcohol amines such as 1,3-propanediol and choline.

  As the α-olefin-maleic anhydride copolymer represented by the general formula (A), those appropriately synthesized may be used, or commercially available products may be used. Examples of the commercially available products include T-YP112, T-YP115, T-YP114, T-YP116 (all manufactured by Seiko PMC Corporation).

  As the styrene- (meth) acrylic copolymer, an appropriately synthesized product or a commercially available product may be used. Examples of the commercially available products include JC-05 (manufactured by Seiko PMC Co., Ltd.), ARUFON UC-3900, ARUFON UC-3910, ARUFON UC-3920 (manufactured by Toagosei Co., Ltd.), and the like.

  As said water-soluble polyurethane resin, what was synthesize | combined suitably may be used and a commercial item may be used. As this commercial item, Takerak W-5025, Takerak W-6010, Takerak W-5661 (made by Mitsui Takeda Chemical Co., Ltd.) etc. are mentioned, for example.

  As said water-soluble polyester resin, what was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available products include Nichigo Polyester W-0030, Nichigo Polyester W-0005S30WO, Nichigo Polyester WR-961 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), pesresin A-210, pesresin A-520 (Takamatsu Oils and Fats). Etc.).

  The acid value of the polymer dispersion stabilizer is preferably 40 mgKOH / g to 400 mgKOH / g, more preferably 60 mgKOH / g to 350 mgKOH / g. When the acid value is 40 mgKOH / g or more, the solubility of the alkaline solution is sufficiently exhibited. Further, when the acid value is 400 mgKOH / g or less, it is possible to suppress the increase in the viscosity of the pigment and the deterioration of the discharge, and to improve the dispersion stability of the pigment dispersion.

  The mass average molecular weight of the polymer dispersion stabilizer is preferably 20,000 or less, and more preferably 5,000 to 20,000. When the mass average molecular weight is 5,000 or more, the dispersion stability of the pigment dispersion can be improved. Moreover, when the said mass mean molecular weight is 20,000 or less, the solubility of an alkaline solution can be made favorable and it can suppress that a viscosity becomes high.

  As content of the said polymer dispersion stabilizer, 1 mass part-100 mass parts (solid content conversion) are preferable with respect to 100 mass parts of said pigments, and 5 mass parts-50 mass parts are more preferable. When the content is 1 part by mass or more, the effect of stabilizing the dispersion is sufficiently exhibited. In addition, when the content is 100 parts by mass or less, it is possible to suppress an increase in ink viscosity and a deterioration in dischargeability from the nozzle, and it is also advantageous in terms of economy.

  In the said other form, it is preferable that the said colorant contains a pigment dispersant. As the pigment dispersant, either an anionic surfactant or a nonionic surfactant having an HLB value of 10 to 20 is suitable.

Examples of the anionic surfactant include the following.
Polyoxyethylene alkyl ether acetate, alkylbenzene sulfonate (eg NH ₄ , Na, Ca etc.), alkyl diphenyl ether disulfonate (eg NH ₄ , Na, Ca etc.), dialkyl succinate sulfonate Na salt, naphthalene Sulfonic acid formalin condensate Na salt, polyoxyethylene polycyclic phenyl ether sulfate ester salt (for example, NH ₄ , Na etc.), laurate, polyoxyethylene alkyl ether sulfate salt, oleate and the like.
Among these, dioctyl sulfosuccinic acid Na salt and polyoxyethylene styrene phenyl ether sulfonic acid NH ₄ salt are particularly preferable.

Examples of the nonionic surfactant having an HLB value of 10 to 20 include the following.
Polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene polycyclic phenyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, Such as acetylene glycol.
Among these, polyoxyethylene lauryl ether, polyoxyethylene-β-naphthyl ether, polyoxyethylene sorbitan monooleate, and polyoxyethylene styrene phenyl ether are particularly preferable.

The content of the pigment dispersant is preferably 1 part by mass to 100 parts by mass and more preferably 10 parts by mass to 50 parts by mass with respect to 100 parts by mass of the pigment.
When the content of the pigment dispersant is in the above range, sufficiently fine pigment can be stabilized and there are few excess components that are not adsorbed on the pigment. It is possible to suppress the influence of image blurring and deterioration of water resistance and abrasion resistance.

A pigment dispersion that is uniformly finely dispersed in water by the pigment dispersant can be prepared as follows. That is, first, the above pigment dispersant is dissolved in an aqueous medium, and then the above pigment is added and sufficiently wetted. Thereafter, it can be produced by a method using high-speed stirring by a homogenizer, a disperser using a ball such as a bead mill or a ball mill, a kneading disperser using a shearing force such as a roll mill, an ultrasonic disperser, or the like.
However, after such a kneading and dispersing step, coarse particles are often included, which may cause clogging of the ink jet nozzle and the supply path. Need to be removed.

The average particle diameter (D50) of the pigment dispersion is preferably 150 nm or less, more preferably 100 nm or less in the ink.
When the average particle diameter (D50) is 150 nm or less, the ejection stability is greatly improved, and the occurrence frequency of nozzle clogging and ink bending is reduced. Further, when the average particle diameter (D50) is 100 nm or less, the ejection stability is improved and the chroma of the image is also improved.

The content of the colorant in the inkjet ink is preferably 1% by mass to 15% by mass and more preferably 3% by mass to 12% by mass in terms of solid content.
When the content is 2% by mass or more, the color developability and image density of the ink are increased, and when the content is 15% by mass or less, the viscosity of the ink is suppressed to improve the ejection property, and the color distortion is small. Is also preferable.

<Surfactant>
As the surfactant, those having low surface tension, low penetrability, and high leveling properties are preferred without impairing dispersion stability depending on the type of the colorant or the combination of the wetting agent. For example, at least one selected from an anionic surfactant, a nonionic surfactant, a silicone surfactant, a fluorine surfactant, an acetylene glycol surfactant, and an acetylene alcohol surfactant is suitable. is there. Among these, silicone surfactants, fluorine surfactants, acetylene glycol surfactants, and acetylene alcohol surfactants are particularly preferable. These may be used alone or in combination of two or more.

  As the fluorine-based surfactant, those having 2 to 16 carbon atoms substituted with fluorine are preferable, and those having 4 to 16 carbon atoms substituted with fluorine are more preferable. When the fluorine-substituted carbon number is 2 or more, the effect of fluorine can be sufficiently obtained. Further, when the fluorine-substituted carbon number is 16 or less, ink storage stability can be improved.

Examples of the fluorosurfactant include the following.
Perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphoric acid ester compounds, perfluoroalkyl ethylene oxide adducts, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain, and the like.
Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is particularly preferable because of its low foaming property.
More preferably, it is a fluorine-type surfactant represented by the following general formula (XIIa) or (XIIb) mentioned later.

Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate.
Examples of the perfluoroalkyl carboxylic acid compound include perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylate.
Examples of the perfluoroalkyl phosphate compound include perfluoroalkyl phosphate esters and perfluoroalkyl phosphate salts.
Examples of the perfluoroalkylethylene oxide adduct include polyoxyethylene perfluoroalkyl alcohol ether, polyoxyethylene polyoxypropylene perfluoroalkyl alcohol ether, polyoxyethylene perfluoroalkyl carboxylic acid ester, polyoxyethylene polyoxypropylene Examples include perfluoroalkyl carboxylic acid esters. These are commercially available, for example, Capstone Capstone FS-30, FS-31, FS-3100, FS-34, FS-35, Zonyl FSN-100, FSN, FSO-100. , FSO, FS-300 (all manufactured by DuPont), FT-250, FT-251 (all manufactured by Neos Co., Ltd.) and the like.

Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include the following.
Polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, sulfate salt of polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, polyoxyalkylene ether having a perfluoroalkyl ether group in the side chain Polymer salt etc.

Examples of salt counter ions in these fluorosurfactants include 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) _{3 and the} like.

Examples of anionic fluorine-based surfactants, nonionic fluorine-based surfactants, amphoteric fluorine-based surfactants and oligomer-type fluorine-based surfactants are shown below.
(1) Anionic fluorine-based surfactant Examples of the anionic fluorine-based surfactant include perfluoroalkylsulfonic acid compounds and perfluoroalkylcarboxylic acid compounds. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate. As said perfluoroalkyl carboxylic acid compound, perfluoroalkyl carboxylic acid, perfluoroalkyl carboxylate, etc. are mentioned, for example.

Examples of the anionic fluorine-based surfactant include those represented by the following general formulas (IV), (VII), (IX), and (X).
However, in the general formula (IV), Rf represents a mixture of fluorine-containing hydrophobic groups represented by the following structural formula (V) or structural formula (VI). In the general formula (IV), A is —SO ₃ X, —COOX, or —PO ₃ X (where X is a counter ion, specifically, a hydrogen atom, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , or NH (CH ₂ CH ₂ OH) ₃ may be mentioned).

However, in said general formula (VII), Rf 'represents the fluorine-containing group represented by the following general formula (VIII), X represents the same meaning as the above, n is an integer of 1 or 2, and m is 2 -N is represented.

However, in said general formula (VIII), n represents the integer of 3-10.

However, in the said general formula (IX), Rf 'and X represent the same meaning as the above.

However, in said general formula (X), Rf 'and X represent the same meaning as the above.

(2) Nonionic fluorosurfactant Examples of the nonionic fluorosurfactant include those represented by the following general formulas (XI), (XIIa) and (XIIb).
However, in said general formula (XI), Rf represents the same meaning as the above, and n represents the integer of 5-20.

More preferably, it is a fluorine-type surfactant represented by the following general formula (XIIa) or (XIIb).
(General formula XIIa)
_{CF 3 CF 2 (CF 2 CF} 2) m -CH 2 CH 2 O (CH 2 CH 2 O) n H
However, in said general formula (XIIa), m represents the integer of 1-10 and n represents the integer of 1-40.

(General formula XIIb)
_{C n F 2n + 1 -CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y '
In the general formula (XIIb), n is an integer from 2 to 6, a is an integer from 15 to 50, Y 'is -C _b H _{2b +} 1 _(b is an integer of 11 to 19 ) or _{-CH 2 CH (OH) CH 2} -C d F 2d + 1 (d represents a a a) an integer from 2 to 6.

In the compound represented by the general formula (XIIa), the molecular weight (MWEO) of the polyoxyethylene group [(CH ₂ CH ₂ O) _a portion] and the fluoroalkyl group (C _n F _{2n + 1} portion and C _m F _{2m + 1} part) molecular weight (MWF) preferably satisfies the relationship of formula: MWEO / MWF = 2.2 to 10 for reasons such as surfactant function and solubility in water. .

Preferable examples of the compound represented by the general formula (XIIb) include compounds represented by the following formulas (a) to (v) for reasons such as high ability to lower surface tension and high permeability.
_{(A): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 21 -C 12 H 25
_{(B): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 25 -C 12 H 25
_{(C): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 30 -C 12 H 25
_{(D): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 20 -C 14 H 29
_{(E): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 30 -C 14 H 29
_{(F): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 20 -C 16 H 33
_{(G): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 23 -C 16 H 33
_{(H): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 25 -C 16 H 33
_{(I): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 30 -C 16 H 33
_{(J): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 40 -C 16 H 33
_{(K): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 20 -C 18 H 37
_{(L): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 30 -C 18 H 37
_{(M): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 40 -C 18 H 37
_{(N): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 23 -CH 2 CH (OH) CH 2 -C 4 F 9
_{(O): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 35 -CH 2 CH (OH) CH 2 -C 4 F 9
_{(P): C 4 F 9} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 45 -CH 2 CH (OH) CH 2 -C 4 F 9
_{(Q): C 6 F 13} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 21 -C 12 H 25
_{(R): C 6 F 13} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 25 -C 12 H 25
_{(S): C 6 F 13} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 30 -C 12 H 25
_{(T): C 6 F 13} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 23 -CH 2 CH (OH) CH 2 -C 6 F 13
_{(U): C 6 F 13} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 35 -CH 2 CH (OH) CH 2 -C 6 F 13
_{(V): C 6 F 13} -CH 2 CH (OH) CH 2 O- (CH 2 CH 2 O) 45 -CH 2 CH (OH) CH 2 -C 6 F 13
Among these, the compounds of the formulas (a) to (c) and the compounds of the formulas (n) to (v) having good compatibility with the organic solvent are particularly preferable.

(3) Amphoteric fluorinated surfactants Examples of the amphoteric fluorinated surfactants include those represented by the following general formula (XIII).
However, in the general formula (XIII), Rf represents the same meaning as described above.

(4) Oligomer type fluorosurfactant Examples of the oligomer type fluorosurfactant include those represented by the following general formulas (XIV) and (XVI).
However, in the general formula (XIV), Rf ″ represents a fluorine-containing group represented by the following general formula (XV). N represents an integer of 1 to 10, and X represents the same meaning as described above.

However, in said general formula (XV), n represents the integer of 1-4.
However, in said general formula (XVI), Rf "represents the same meaning as the above, l is an integer of 1-10, m is an integer of 0-10, n represents an integer of 1-10.

As said fluorosurfactant, what was synthesize | combined suitably may be used and a commercial item may be used. As this commercial item, the following are mentioned, for example.
Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95 , FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all are manufactured by Sumitomo 3M Limited); Megafac F-470, F-1405, F-474 (any Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont); FT-110, FT- 250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-151N Manufactured by OMNOVA Solutions Inc.) and the like.
Among these, from the point that the good print quality, particularly the color developability and the leveling property on paper are remarkably improved, FS-300 manufactured by DuPont, FT-110, FT-250, FT-251 manufactured by Neos Co., Ltd., FT-400S, FT-150, FT-400SW and Polynova PF-151N manufactured by Omninova are particularly preferred.

(Silicone surfactant)
There is no restriction | limiting in particular as said silicone type surfactant, Although it can select suitably according to the objective, What does not decompose | disassemble at high pH is preferable. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side chain both terminal modified polydimethylsiloxane and the like can be mentioned. Of these, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group is particularly preferable because it exhibits good properties as an aqueous surfactant.

  As such a surfactant, an appropriately synthesized product or a commercially available product may be used. As said commercial item, it can obtain easily from Big Chemie Co., Ltd., Shin-Etsu Silicone Co., Ltd., Toray Dow Corning Silicone Co., Ltd. etc., for example.

  There is no restriction | limiting in particular as said polyether modified silicone type surfactant, According to the objective, it can select suitably. For example, the compound etc. which introduce | transduced the polyalkylene oxide structure represented by the following general formula (XVII) into the Si part side chain of dimethylpolysiloxane are mentioned.

However, in said general formula (XVII), m, n, a, and b represent an integer greater than or equal to 1, R and R 'represent an alkyl group and an alkylene group. Further, it is _{X = -R (C 2 H 4} O) a (C 3 H 6 O) b R '.

  As the polyether-modified silicone surfactant, commercially available products can be used. Examples of the commercially available products include KF-618, KF-642, and KF-643 (all manufactured by Shin-Etsu Chemical Co., Ltd.). Etc.

(Acetylene glycol or acetylene alcohol surfactant)
The acetylene glycol surfactant or acetylene alcohol surfactant is preferably a compound represented by the following general formula (5) or the following general formula (6). Specifically, the compound of following formula (7) etc. are mentioned.

<General formula (5)>
However, in the general formula (5), m or n represents an integer of 1 or more.

<General formula (6)>
However, in said general formula (6) Formula, R < ₁ > and R < ₂ > represents an alkyl group.

<Formula (7)>

  As the acetylene glycol surfactant or acetylene alcohol surfactant, commercially available products can be used, and examples of the commercially available products include the following. DYNOL 604, DYNOL 607 (manufactured by Air Products and Chemicals); surfinol 104, surfinol 420, surfinol 440, surfinol SE (manufactured by Nissin Chemical Industry Co., Ltd.); 4001, Olfine EXP. 4200, Olfine EXP. 4051F, Olfine EXP. 4123 (manufactured by Nissin Chemical Industry Co., Ltd.).

(Anionic surfactant)
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
(Nonionic surfactant)
Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, and polyoxyethylene alkyl. Examples include amines and polyoxyethylene alkylamides.

  The content of the surfactant in the inkjet ink is preferably 0.01% by mass to 3.0% by mass, and more preferably 0.5% by mass to 2.0% by mass. When the content is 0.01% by mass or more, the effect of adding the surfactant appears in the ink physical properties. In addition, the nozzle surface of the inkjet head holds the interface between the ink and the nozzle surface in order to maintain the meniscus of the nozzle hole, but keeps the meniscus uniformly up to a surfactant concentration of 3.0% by mass. I can do it.

<Water dispersible resin>
The water-dispersible resin preferably has excellent film-forming properties (image forming properties) and has high water repellency, high water resistance, and high weather resistance. As a result, an image having high water resistance and high image density (high color development) can be obtained.

Examples of the water-dispersible resin include condensation-type synthetic resins, addition-type synthetic resins, and natural polymer compounds.
Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin. Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like. Examples of the natural polymer compound include celluloses, rosins, and natural rubber.
These may be used individually by 1 type and may use 2 or more types together. Among these, polyurethane resin fine particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are particularly preferable.
Such a water-dispersible resin may be used as a homopolymer, or may be used as a composite resin by being used as a copolymer. Any one of a single-phase structure type, a core-shell type, and a power feed type emulsion may be used. Can also be used.

Since the ink used in the present invention is intended to be used for outdoor applications such as posters and billboards, it is preferable that it can form a coating film having excellent long-term weather resistance. From the viewpoint of the strength of the coating film, the water-dispersible resin is preferably polyurethane resin fine particles, and more preferably a polycarbonate urethane resin excellent in water resistance, heat resistance, abrasion resistance, and weather resistance.
As described above, light resistance is often required, and from this viewpoint, the isocyanate compound used when producing polyurethane is preferably an aliphatic or alicyclic diisocyanate.

  Further, in the ink used in the present invention, the water-dispersible resin is preferably obtained using at least one alicyclic diisocyanate. When the polycarbonate urethane resin fine particles have a structure derived from alicyclic diisocyanate, the scratch resistance and ethanol resistance are further improved. Particularly preferred are isophorone diisocyanate and dicyclohexylmethane diisocyanate. Moreover, it is preferable that the ratio of alicyclic diisocyanate is 60 mass% or more in all the isocyanate compounds.

  In the ink used in the present invention, the urethane resin fine particles are added in the form of a resin emulsion dispersed in an aqueous medium. The resin solid content in the resin emulsion is preferably 20% by mass or more. If the resin solid content is 20% by mass or more, there will be no problem in the formulation design when making an ink. The volume average particle diameter of the urethane resin fine particles is preferably in the range of 10 to 350 nm from the viewpoint of liquid storage stability and ejection stability when converted into an ink.

In addition, when dispersing the urethane resin fine particles in an aqueous medium, a forced emulsification type using a dispersant may be used. A so-called self-emulsifying type having an anionic group on the surface is preferred. In that case, it is preferable to have an anionic group in a ratio that the acid value is 20 to 100 in order to impart excellent scratch resistance and chemical resistance.
Such urethane resin fine particles can be obtained by a conventionally known production method.

Further, since the use of the polycarbonate-based urethane resin fine particles has high heat resistance, it can be dried by heating after printing to reduce residual solvent and improve adhesiveness. The minimum film-forming temperature of the polycarbonate-based urethane resin fine particles is not necessarily lower than room temperature. However, in the case of drying by heating, it is desirable that the temperature is at least lower than the temperature to be heated after printing. Low is desirable. For example, when the heating temperature is 60 ° C, the minimum film-forming temperature of the resin is preferably in the range of 0 ° C to 55 ° C, more preferably in the range of 25 ° C to 55 ° C. In general, the lower the film-forming temperature is, the better the film-forming property is. However, if the minimum film-forming temperature is too low, the glass transition point of the resin is lowered and sufficient film strength cannot be obtained.
The polycarbonate-based urethane resin fine particles preferably have a surface hardness of 100 N / mm ² or more when a coating film is formed. When this condition is satisfied, the ink forms a tough coating film, and stronger scratch resistance is obtained.
The surface hardness can be measured, for example, by the following method.
A polycarbonate urethane resin emulsion is applied onto a slide glass so as to have a film thickness of 10 μm, and then dried at 100 ° C. for 30 minutes to form a resin film. About the formed resin film, using a micro surface hardness tester (FISCHERSCOPE HM2000, manufactured by Fischer), the indentation depth when the Barkovic indenter was indented with a load of 9.8 mN was obtained, and the Martens hardness described in ISO14577-2002 was obtained. It can be measured.

  The addition amount of such water-dispersible resin in the ink is preferably 0.5 to 10% by mass in terms of solid content, more preferably 1 to 8% by mass, and further preferably 3 to 8% by mass. . When the addition amount is 0.5% by mass or more, a sufficient coating is formed on the pigment, and the required image fastness can be obtained. Further, when the addition amount is 10% by mass or less, there is no case where the viscosity becomes too high and the discharge becomes difficult.

<Other ingredients>
In addition to the above-described components, the ink used in the present invention may contain other components such as an antiseptic / antifungal agent, a rust inhibitor, and a pH adjuster as necessary.

Examples of antiseptic / antifungal agents include 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, sodium sorbate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, and the like.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  As the pH adjuster, any substance can be used as long as it can adjust the pH to a desired value without adversely affecting the ink to be prepared. Examples include the following. Alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, carbonates of alkali metals such as lithium carbonate, sodium carbonate and potassium carbonate, quaternary ammonium hydroxides, diethanolamine and triethanolamine Such as amine, ammonium hydroxide, quaternary phosphonium hydroxide and the like.

  The ink of the present invention is prepared by dissolving the above-described constituents in an aqueous medium and further stirring and mixing as necessary. Stirring and mixing can be performed, for example, with a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like.

<Ink cartridge>
The ink cartridge used in the image recording apparatus of the present invention contains the ink-jet ink in a container, and further includes other members appropriately selected as necessary.
There is no restriction | limiting in particular as said container, According to the objective, the shape, a structure, a magnitude | size, a material, etc. can be selected suitably. For example, a material having at least an ink bag formed of an aluminum laminate film, a resin film, or the like is preferably used.

Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 1 is a schematic view showing the ink cartridge, and FIG. 2 is a schematic view showing a modification of the ink cartridge of FIG.
As shown in FIG. 1, the ink bag 241 is filled with the ink-jet ink of the present invention from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, a needle of the apparatus main body 101 of the ink jet recording apparatus, which will be described later with reference to FIG. 3, is pierced into the ink discharge port 243 made of a rubber member, and the ink is supplied to the apparatus main body 101.

The ink bag 241 is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 2, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably mounted on various ink jet recording apparatuses.
The ink cartridge 201 accommodates the ink-jet ink (ink set) and can be used by being detachably attached to various ink-jet recording apparatuses. Further, it is particularly preferable that the ink jet recording apparatus of the present invention described later is detachably mounted.

<Image recording method and image recording apparatus>
The image recording method of the present invention includes a printing process for forming an image by adhering ink in a range where the surface temperature on the recording surface side of the non-porous recording medium is 40 ° C. or higher and 60 ° C. or lower, and an unfixed image. And a drying step in which drying and fixing are performed. The printing process includes at least an ink flying process. Further, the image recording method includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.

  The image recording apparatus of the present invention comprises a printing means for forming an image by adhering ink with a surface temperature on the recording surface side of a non-porous recording medium in the range of 40 ° C. or more and 60 ° C. or less, and an unfixed image. A heating and drying means for heating and fixing by heating. The printing unit includes at least an ink flying unit. Further, the image recording apparatus includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.

  The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

-Ink flying process and ink flying means-
The ink flying step is a step of forming an image on a recording medium by applying a stimulus (energy) to the ink jet ink used in the present invention and causing the ink jet ink to fly.
The ink flying means is means for applying an stimulus (energy) to the ink jet ink used in the present invention and causing the ink jet ink to fly to form an image on a recording medium. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.

In the present invention, it is preferable that at least a part of the liquid chamber portion, the fluid resistance portion, the vibration plate, and the nozzle member of the inkjet head is formed of a material containing at least one of SUS, silicon, and nickel. Since SUS is compatible with a wide range of liquid inks and has high thermal conductivity, a head composed of a SUS member can form a head with excellent temperature controllability. In addition, when silicon is used, processing can be performed using semiconductor technology or MEMS technology, so that extremely fine and high-precision processing can be performed. As for the nickel member, a metal thin film can be manufactured by an electroforming technique, and a highly accurate shape can be created. Nickel is easily dissolved by acidification, so the ink adaptability is low, but by electroforming with an alloy such as palladium, it is possible to produce metal thin film parts with high durability and excellent workability .
Further, the nozzle diameter of the inkjet nozzle is preferably 30 μm or less, and more preferably 1 μm to 20 μm.

The stimulus (energy) can be generated by, for example, the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose. Heat (temperature), pressure, vibration, For example, light. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable.
Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, and a light. Specifically, the following are mentioned, for example. Piezoelectric actuators such as piezoelectric elements, thermal actuators that use phase change due to liquid film boiling using electrothermal transducers such as heating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, static electricity that uses electrostatic forces Electric actuator etc.

There is no restriction | limiting in particular as an aspect of the said inkjet ink flight, It changes according to the kind etc. of the said stimulus.
For example, when the stimulus is “heat”, ink can be ejected as follows.
First, thermal energy corresponding to a recording signal is applied to the ink-jet ink in the recording head using, for example, a thermal head. Then, bubbles can be generated in the inkjet ink by the thermal energy, and the inkjet ink can be ejected and ejected as droplets from the nozzle holes of the recording head by the pressure of the bubbles.

Further, when the stimulus is “pressure”, for example, ink can be ejected as follows.
First, a voltage is applied to a piezoelectric element bonded to a position called a pressure chamber in the ink flow path in the recording head. As a result, the piezoelectric element is bent, the volume of the pressure chamber is reduced, and the inkjet ink can be ejected and ejected as droplets from the nozzle holes of the recording head.

The size of the droplets of the inkjet ink to be ejected is preferably 3 × 10 ¹⁵ m ³ to 40 × 10 ¹⁵ m ³ ( ³ pL to 40 pL), for example. Further, the speed of the ejection injection is preferably 5 m / s to 20 m / s, the drive frequency is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.

The image recording method includes a step of heating and drying the recording medium on which the ink jet ink is ejected.
In this case, the printing paper (porous recording medium) can be dried with an infrared drying device, a microwave drying device, a roll heater, a drum heater, or hot air.
In the present invention, by promoting dry fixing during printing, drying immediately after ink adhesion is promoted, and movement of the liquid is suppressed. As a result, beading and bleeding can be suppressed, and printability and image quality on non-absorbing media can be improved. Further, by promoting drying, the resin component in the ink component can easily form a film, and the fixability immediately after printing can be improved.

  As described above, in order to promote the drying and fixing during printing, it is necessary to heat the medium before printing or to heat it during printing. The heating is performed so that the heated medium is 40 to 60 ° C. under the ink discharge head. Heating in the vicinity of the ink ejection head dries the meniscus of the head nozzle portion and deteriorates ejection performance. Therefore, 40-60 degreeC under a head is more preferable. Such heating can be performed in the heating and drying step. In these heating processes, the heating state is changed according to the printing conditions. A capacitor can also be used in combination to cover the power used for rapid heating.

  The heating temperature can be changed according to the type and amount of the water-soluble organic solvent contained in the ink and the minimum film-forming temperature of the water-dispersed resin to be added, and further changed depending on the type of the substrate to be printed. be able to. The heating temperature is preferably high from the viewpoints of drying property and film forming temperature, but if the heating temperature is too high, the substrate to be printed is damaged. The heater during printing is not preferable because the heater may be overheated or the ink head may be heated and non-ejection may occur. Therefore, it is possible to form a good image without color bleed or dot fusion by printing the surface temperature of the non-porous recording medium on the recording surface side in the range of 40 to 60 ° C. At this time, by reducing the surface temperature according to the increase in the number of print scans, excessive drying immediately after printing can be suppressed, and the dot diameter can be increased, the resulting solid uniformity can be improved, and the image density can be improved. I can do it.

Further, a fixing step may be provided in which heat is fixed to 70 ° C. to 120 ° C. by heating means as drying after printing.
By providing this fixing step, the gloss and fixability of the ink recorded matter are improved. Here, as the heat fixing means, a roller having a heated mirror surface, a drum heater or the like is preferably used, and the mirror surface portion (smooth portion) of the roll heater or drum heater can be brought into contact with the image forming surface.

Regarding the heating temperature after printing, a fixing roller heated to 70 ° C. to 100 ° C. is preferable in consideration of heat resistance of the media, image quality, safety and economy.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

<Inkjet recording>
The ink jet recorded matter obtained by the image recording method of the present invention has an image formed on the recording medium using the ink of the present invention.
The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, and the like can be used, but the ink used in the present invention is particularly suitable when applied to a non-porous recording medium. By performing the recording method, an image having good gloss and image fastness can be provided.

  The non-porous recording medium is made of a plastic material such as transparent or colored polyvinyl chloride film, polyethylene terephthalate (PET) film, polycarbonate film, acrylic film, polypropylene film, polyimide film, polystyrene film, and wood pulp. Representative examples include paper, Japanese paper, synthetic pulp paper, synthetic fiber paper and the like that do not contain paper components. However, the ink used in the present invention exhibits sufficient performance with respect to other non-porous recording medium materials and conventionally used porous recording media such as plain paper and inorganic-coated porous recording media.

<Detailed description of device>
Here, an aspect of carrying out the image recording method of the present invention using a serial type ink jet recording apparatus as an example of the image recording apparatus of the present invention will be described with reference to the drawings.
The ink jet recording apparatus shown in FIG. 3 has an apparatus main body 101, a paper feed tray 102 for loading paper into the apparatus main body 101, and a sheet for forming (recording) an image formed (recorded) on the apparatus main body 101. A paper discharge tray 103 and an ink cartridge loading unit 104 are provided. On the upper surface of the ink cartridge loading unit 104, an operation unit 105 such as operation keys and a display is arranged. The ink cartridge loading unit 104 has an openable / closable front cover for attaching and detaching the ink cartridge 201 shown in FIG. 1 or FIG.

  As shown in FIGS. 3 and 4, the apparatus main body 101 is provided with a guide rod 131 and a sub guide rod 132 which are guide members horizontally mounted on left and right side plates (not shown). The guide rod 131 and the sub guide rod 132 hold the carriage 133 slidably in the main scanning direction, and the main scanning motor moves and scans in the direction indicated by the arrow in FIG.

  The carriage 133 is provided with four inkjet recording heads that eject inkjet ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). On the carriage 133, a recording head 134 composed of the four inkjet recording heads is arranged with a plurality of ink discharge ports arranged in a direction crossing the main scanning direction, and the ink droplet discharge direction is directed downward. .

As the ink jet recording head constituting the recording head 134, for example, one provided with the following means as energy generating means for discharging ink can be used.
Piezoelectric actuators such as piezoelectric elements, thermal actuators that use phase change due to liquid film boiling using electrothermal transducers such as heating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, static electricity that uses electrostatic forces Electric actuator etc.

  In addition, the carriage 133 is equipped with a sub tank 135 for each color for supplying ink of each color to the recording head 134. The sub tank 135 is supplied with ink jet ink from the ink cartridge 201 loaded in the ink cartridge loading section 104 via an ink jet ink supply tube (not shown).

  On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feeding tray 102, a half-moon roller (feeding) that separates and feeds the paper 142 from the paper stacking unit 141 one by one. A paper roller 143) is provided. Further, a separation pad made of a material having a large friction coefficient is provided so as to face the sheet feeding roller 143. The separation pad is urged toward the paper feed roller 143 side.

  In the conveyance unit for conveying the sheet 142 fed from the sheet feeding unit to the lower side of the recording head 134, the sheet 142 is sent to the sheet feeding roller 157 and the counter roller 154 through the guide roller 152. Transport to. The paper 142 is conveyed while being held by the paper feed roller 157 and the counter roller 154, and printing is performed by the recording head 134. Then, the printed paper 142 is held by the paper discharge roller 172 and the spur roller 173 and is discharged from the printing unit.

A guide member 161 is arranged corresponding to the printing area by the recording head 134, and a printing heater 184 is arranged on the back surface of the guide member 161. The heat from the heater 184 during printing warms the guide member 161 and heats the paper 142 in the printing area.
The sheet 142 discharged from the printing unit is dried by the warm air heater 181 and the infrared heater 182 on the printing surface and the back surface heater 183 on the back surface to dry the sheet. A plurality of spur rollers 171 are provided to prevent the paper 142 from contacting the hot air heater 181 and the infrared heater 182 and to be in close contact with the back heater, and the paper is conveyed to the paper discharge tray 103.

Printing is performed as follows. First, the recording head 134 is driven according to the image signal while moving the carriage 133 with respect to the paper 142 conveyed under the recording head 134, and ink droplets are ejected onto the stopped paper 142 to record one line. To do. Subsequently, after the sheet 142 is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 142 has reached the recording area, the recording operation is terminated and the sheet 142 is discharged onto the discharge tray 103.
When a near-end of the ink jet ink in the sub tank 135 is detected, a required amount of ink jet ink is supplied from the ink cartridge 201 to the sub tank 135. In this ink jet recording apparatus, when the ink for ink jet in the ink cartridge 201 is used up, the casing of the ink cartridge 201 can be disassembled and only the ink bag 241 inside can be replaced.

Next, an outline of the control unit of the image recording apparatus of the present invention will be described with reference to FIG. This figure is an overall block diagram of the control unit.
The control unit includes a CPU, a ROM, a RAM, a nonvolatile memory (NVRAM), and an ASIC. The CPU controls the entire apparatus. The ROM stores a program executed by the CPU, a printing mode for the predetermined ink used in the present invention, a set temperature value for heating during printing, a heating control range allowable threshold, driving waveform data, and other fixed data. is there. The RAM temporarily stores image data and the like. The non-volatile memory is for holding data while the power of the apparatus is cut off. The ASIC processes image processing for performing various signal processing and rearrangement on image data, and other input / output signals for controlling the entire apparatus.

The control unit includes an I / F, a head drive control unit, a medium transport motor drive unit, a head unit movement motor drive unit, a maintenance unit movement motor drive control unit, a liquid feeding / suction motor drive control unit, and an I / O. I have.
The I / F is used to send and receive data and signals with the host side. The head drive controller generates a drive waveform for driving and controlling the pressure generating means of the recording head. The medium transport motor driving unit is for driving the medium transport motor, and the head unit moving motor driving unit is for driving the head unit moving motor. The maintenance unit movement motor drive control section is for driving the maintenance unit movement motor, and the liquid feeding suction motor drive control section is for controlling the drive of the cap suction motor and the ink supply motor. The I / O includes a detection signal from an encoder that outputs a detection signal corresponding to the moving amount and moving speed of the transport roller, a sensor that detects environmental temperature and environmental humidity (whichever is acceptable), and the temperature during printing. This is for inputting a radiation temperature sensor being measured, a temperature sensor for the heating / fixing heater, a jam detection sensor in the heating / fixing heater, an ink amount detection signal for the sub ink tank, and detection signals from various sensors (not shown).
The control unit is connected to an operation / display unit for inputting and displaying information necessary for the apparatus.

The control unit receives print data from the host side such as an information processing device such as a personal computer, an image reading device such as an image scanner, and an imaging device such as a digital camera, etc., via an I / F via a cable or a network.
Then, the CPU reads and analyzes the print data in the reception buffer included in the I / F, and performs necessary image processing, data rearrangement processing, and the like in the ASIC. Further, the CPU sends image data (dot pattern data) corresponding to one page of the head width of the recording head to the head drive control unit in synchronization with the clock signal.
The dot pattern data for image output may be generated by storing font data in a ROM, for example, or the image data is developed into bitmap data by a host-side printer driver and transferred to this apparatus. You may do it.

Next, the printing operation of the image recording apparatus of the present invention will be described. The image recording apparatus of the present invention can be operated by inputting data from various interfaces. Here, printing by input from a general personal computer will be described.
For an image created by an application on a personal computer, a printing condition is set from a printer driver corresponding to the OS on the personal computer, and a printing operation is instructed. At that time, the printer driver causes the user to select from a plurality of printing conditions to set the printing mode. When the print mode is set, the image resolution, number of gradations, drive waveform, number of print passes, number of scans, print direction, halftone processing, density adjustment, etc. are determined, and data to be sent to the recording device is created according to the print mode .

  The created data is transferred from the interface of the personal computer to the image recording apparatus of the present invention. At this time, information such as the image resolution of the print mode, the number of gradations, the drive waveform, the number of print passes, the number of scans, and the print direction as print data information is sent to the image recording apparatus as header information. The image recording apparatus reads the set temperature of the heater during printing based on the number of print passes and the number of scans sent, and controls the temperature of the heater during printing according to the set value. The temperature can be controlled by controlling the heater from the sensor of the image recording device via the CPU, or the heater during printing has a sensor that stabilizes the temperature by performing feedback control on the set temperature. Also good.

  When the heater is turned on and the temperature is stable, data is transferred and printing proceeds. The image data rasterized by the driver according to the print mode is converted into raster data for each scan, subjected to compression processing for transfer to the image recording apparatus, and transferred from the personal computer interface to the image recording apparatus of the present invention. The The transferred image data is decompressed and decoded as raster data for each scan. Based on the previous drive waveform information, the drive waveform data is read from the ROM, and the drive waveform of the ejection head of the image recording apparatus is set. Thereafter, while the medium is conveyed to the bottom of the head and heated by a heater during printing, ejection is performed while moving the head carriage based on the raster data to create a one-scan image. The medium is transported based on the data, moved by a predetermined amount, discharged again based on the raster data, and an image is created while repeating this operation.

  The obtained image is sent to a dry fixing heater. The sent image is heated at a value set by the print mode or a value set by the user. At this time, if the media is jammed, it may cause a fire. Therefore, it is dried while detecting the jam, and when the jam is detected, the drying and fixing heater is immediately turned off. When a hot air heater is used in combination with a dry fixing heater, the temperature inside the dry fixing heater can be lowered quickly by stopping the heater from the hot air mode and blowing in the cold air mode, which is preferable in terms of fire suppression. . Even when printing is stopped due to out-of-paper or due to a different cause, the possibility of fire increases if the printer is left in the drying / fixing heater for a long time, so that the drying / fixing heater is quickly turned off.

  In addition, although it demonstrated in the example applied to the serial type (shuttle type) inkjet recording device which a carriage scans, it can apply similarly to the line type inkjet recording device provided with the line type head. In the case of a line type ink jet recording apparatus, the same effect as the multi pass printing of the serial type ink jet recording apparatus can be obtained by arranging a plurality of heads of the same color in the printing path, instead of being able to print in multiple passes. Also, instead of lowering the surface temperature of the non-porous recording medium as the number of image print scans increases, lowering the surface temperature as the number of line heads of the same color increases reduces the quality of the printed matter. It is done.

  The image recording method and the image recording apparatus of the present invention can be applied to various recordings by an ink jet recording method. For example, the present invention can be particularly suitably applied to an inkjet recording printer, a facsimile machine, a copying machine, a printer / fax / copier multifunction machine, and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these Examples. In the examples, “part” is “part by mass”.

<Preparation of urethane resin emulsion>
In a reaction vessel into which a stirrer, a reflux condenser and a thermometer were inserted, 1500 g of polycarbonate diol (reaction product of 1,6-hexanediol and dimethyl carbonate), 220 g of 2,2-dimethylolpropionic acid (DMPA) and N-methyl 1347 g of pyrrolidone (NMP) was charged under a nitrogen stream and heated to 60 ° C. to dissolve DMPA.
Next, 1,445 g of 4,4′-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours to obtain an isocyanate-terminated urethane prepolymer. .
Next, the reaction mixture was cooled to 80 ° C., 4340 g was extracted from the mixture in which 149 g of triethylamine was added and mixed, and added to a mixed solution of 5400 g of water and 15 g of triethylamine with vigorous stirring.
Next, 1500 g of ice was added, 626 g of 35% by mass of 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction, and the solvent was distilled off so that the solid content concentration became 30% by mass. [Urethane resin emulsion] was obtained.
This [urethane resin emulsion] was applied on a slide glass so as to have a film thickness of 10 μm, and dried at 100 ° C. for 30 minutes to form a resin film. And, as a result of measuring the Martens hardness when the Vickers indenter was pushed in with a load of 9.8 mN using a micro surface hardness tester (FISCHERSCOPE HM2000, manufactured by Fischer), it was 120 N / mm ² .

<Preparation of surface modified black pigment dispersion>
100 g of Black Pearls (registered trademark) 1000 (carbon black having a BET surface area of 343 m ² / g and DBPA 105 mL / 100 g (dibutyl phthalate absorption measured according to ASTM D2414)) manufactured by Cabot Corporation, and a compound of the following formula (I) 100 mmol and 1 L of ion-exchange high purity water were mixed in a Silverson mixer (6,000 rpm) under a room temperature environment.

<Compound of Formula (I)>

When the pH of the resulting slurry was higher than 4, 100 mmol of nitric acid was added.
After 30 minutes, sodium nitrite (100 mmol) dissolved in a small amount of ion-exchanged high purity water was slowly added to the above mixture.
Further, the mixture was heated to 60 ° C. with stirring and reacted for 1 hour.
A surface-modified pigment in which the compound of formula (I) was added to carbon black was produced.

Subsequently, the surface-modified pigment dispersion was obtained after 30 minutes by adjusting the pH to 10 with an aqueous NaOH solution.
Ultrafiltration using a dialysis membrane was performed using a dispersion containing a pigment bound to at least one geminal bisphosphonic acid group or geminal bisphosphonic acid sodium salt and ion-exchanged high-purity water. Furthermore, ultrasonic dispersion was performed to obtain [Surface-modified black pigment dispersion] in which the pigment solid content was concentrated to 20% by mass.

The surface treatment level of the obtained [surface-modified black pigment dispersion] was 0.75 mmol / g, and the volume average particle size (D50) measured with a particle size distribution measuring device (Nanotrack UPA-EX150, manufactured by Nikkiso Co., Ltd.). ) Was 120 nm.
Furthermore, when sodium ion content was measured using TOA-DKK ion meter IM-32P, it was 27,868 ppm and the amount of phosphorus (P) measured by elemental analysis was 2.31% by mass.

<Preparation of surface modified yellow pigment dispersion>
690 g of SMART Yellow 3074BA (C.I. Pigment Yellow 74 surface treatment dispersion, pigment solid content 14.5 mass%) manufactured by SENSIENT, 50 mmol of the compound of the above formula (II), and 500 mL of ion-exchange high-purity water at room temperature Mixing was performed using a Silverson mixer (6,000 rpm) under the environment.

<Compound of formula (II)>

After 30 minutes, sodium nitrite (100 mmol) dissolved in a small amount of ion exchange high purity water was slowly added to the mixture.
Further, the mixture was heated to 60 ° C. with stirring and reacted for 1 hour.
C. I. A surface-modified pigment obtained by adding the compound of the above formula (II) to Pigment Yellow 74 was produced.

Subsequently, the surface-modified pigment dispersion was obtained after 30 minutes by adjusting the pH to 10 with tetrabutylammonium hydroxide.
Perform ultrafiltration using a dialysis membrane using a dispersion containing pigment combined with at least one geminal bisphosphonic acid group or geminal bisphosphonic acid tetrabutylammonium salt, and ion-exchanged high-purity water, followed by ultrasonic dispersion Thus, [Surface modified yellow pigment dispersion] was obtained by concentrating the pigment solid content to 20% by mass.

The surface treatment level of the obtained surface-modified yellow pigment dispersion was 0.50 mmol / g, and the volume average particle diameter (D50) measured with a particle size distribution measuring device (Nikki Co., Ltd., Nanotrac UPA-EX150) was 142 nm.
Furthermore, the amount of phosphorus (P) measured by elemental analysis was 0.26% by mass.

<Preparation of ink>
The ink was prepared according to the following procedure according to Table 1.
First, a water-soluble organic solvent, a surfactant, an antifoaming agent, an antibacterial agent, and water were mixed and stirred uniformly for 15 minutes. [Urethane resin emulsion] was added to this mixed liquid and stirred for 15 minutes, and then [surface modified black pigment dispersion] or [surface modified yellow pigment dispersion] as a colorant was added and stirred for 30 minutes. Thereafter, the mixture was filtered under pressure through a 0.8 μ cellulose acetate membrane filter to remove coarse particles, and an evaluation ink was obtained.

In addition, the prepared ink was put in a petri dish having a diameter of 26.6 mm so that the exposed surface area of the ink was 5 mg / mm ² , dried in a thermostatic chamber adjusted to 25 ° C. and 8% RH, and dried. The mass of ink in the petri dish was measured, and the time until a 25% mass reduction was obtained to calculate the mass change rate. FIG. 6 is a graph showing the relationship between the evaporation rate and the elapsed time for each ink. In FIG. 6, the vertical axis represents the elapsed time (min), and the horizontal axis represents the evaporation rate (%).
The mass change rate is shown below together with the amount of the water-soluble organic solvent contained in the ink.

Based on these prepared inks, an ink set was prepared as follows, and the characteristics were evaluated.

The characteristic value evaluation method and criteria are shown below.
<Printing conditions>
The exterior was removed, and the ink supply path including the print head of an ink jet printer (IPSiO GXe3300 manufactured by Ricoh Co., Ltd.) equipped with a multi-manual feeder was washed by passing pure water. The washing liquid was sufficiently passed until it was not colored, and the liquid was completely removed from the apparatus to obtain an evaluation printing apparatus.
Further, the evaluation ink was stirred for 30 minutes under a reduced pressure condition of 5 to 10 Pa to degas the gas in the ink and filled in the ink cartridge to obtain an evaluation ink cartridge. The ink cartridge for evaluation using the black pigment was replaced with the magenta ink cartridge of the printing apparatus and attached. Further, the evaluation ink cartridge using the yellow pigment was replaced with the yellow ink cartridge of the printing apparatus and attached. The black and cyan printing devices were filled with genuine IPSiO GXe3300 ink cartridges.

  The image is a double-sided tape (3309, 4309) with a PVC film (Roland Dizzy, DGS-210-WH) against a film heater (Zico, PIFH-O-15-15) at 23 ° C and 40% RH. The paper was fed from a multi-manual feeder and printed. During this printing, the surface temperature in the vicinity of the head printing area was measured with a non-contact radiation thermometer, and the surface temperature of the recording medium during printing was determined. After printing, the recording medium was placed in a constant temperature bath at 80 ° C. and dried for 1 hour for evaluation.

In addition, the printing mode in the output of the printer was printed as an image created with Microsoft Word 2003 as color matching off by user setting after selecting the following mode with the driver attached to the printer.
As shown in Table 4 below, the standard modes used for evaluation are the four levels of "plain paper-fast", "plain paper-clean", "high grade plain paper-clean", and "glossy paper-clean". The number of print scans increases in the order of arrangement, the print speed decreases, and the amount of ink attached increases.

[Evaluation method]
<Abrasion resistance>
As a print image, a solid image of black ink using a black pigment to be evaluated was printed by designating a magenta color (RGB = 255, 0, 255) created by an auto shape of Microsoft Word 2003.
After printing and drying, the solid portion of the image was rubbed with dry cotton (Kanakin No. 3) under a load of 400 g, and scratch resistance was evaluated according to the following criteria.
〔Evaluation criteria〕
A: The image does not change even after rubbing 51 times or more.
B: Some scratches remain after rubbing 50 times, but the image density is not affected and there is no practical problem.
C: Image density decreases during rubbing 21 to 49 times.
D: Image density is lowered by rubbing 20 times or less.

<Color bleed>
A solid image of yellow (RGB = 255, 255, 0) is created by the Microsoft Word 2003 auto shape as a print image, and a magenta color (RGB = 255, 0, 255) is specified in the yellow solid image. A superposed image of 0.5 mm line images of printed black ink was used as an evaluation image.
After printing and drying, the occurrence of “color boundary bleeding” that occurs when the yellow ink and the black ink adjoin each other was visually observed, and judged according to the following evaluation criteria.
〔Evaluation criteria〕
A: No problem B: Slightly generated but no problem C: Slightly generated and problematic D: Problem due to occurrence

<Beading>
A solid image of black ink using the black pigment to be evaluated was printed by printing by specifying the magenta color (RGB = 0, 255, 0) created by the auto shape of Microsoft Word 2003 and drying it. Thereafter, the degree of beading (density unevenness) of the obtained black solid part was visually evaluated.
The rank evaluation was performed using a five-stage sample (rank 1: defective to rank 5: good).
〔Evaluation criteria〕
A: Rank 5
B: Rank 4
C: Rank 3
D: Rank 2 or lower

<Image density>
By printing the magenta color (RGB = 255, 0, 255) created by the auto shape of Microsoft Word 2003, the solid image of the black ink using the black pigment to be evaluated was printed and dried. Thereafter, the solid portion was measured with X-Rite 938 and determined as a black OD according to the following evaluation criteria.
〔Evaluation criteria〕
A: 1.6 or more B: 1.5 or more and less than 1.6 C: 1.4 or more and less than 1.5 D: Less than 1.4

<Evaluation results>
The temperature indicates the surface temperature during printing.
The overall judgment is C if the lowest rank is D, B if C, B if B or more, and A if the lowest rank is obtained with reference to the lowest rank obtained by rubbing, color bleeding, beading, and image density.
The results are shown in Table 5 below.

  As for the scratching property, the scratching property tends to improve even at a low temperature side as the number of scans increases. The ink set 2 containing a solvent of 250 ° C. or higher in ink has poor scratch resistance, and the scratch resistance cannot be improved in any printing mode and surface temperature during printing. On the other hand, the ink sets 1 and 3 which are the embodiments of the present invention have practical scratches at any surface temperature during printing.

Regarding color bleed, there is a tendency for color bleed to decrease even at low temperatures as the number of scans increases. There is a similar trend for beading. The ink set 1 in which the mass change rate up to 25% of the mass change rate of the ink is 0.2% by mass / min or more tends to be greatly affected by the surface temperature during printing.
Regarding the image density, the image density increases as the printing temperature decreases as the number of scans increases.

  The overall evaluation is based on the evaluation of these overall characteristics, but for ink set 1 and ink set 3, as the number of scans increases by changing the print mode, the usable area (B or higher) for comprehensive determination shifts to lower temperatures. doing. FIG. 7 shows graphs of ink set 1 and ink set 3 in which the number of scans and the optimum temperature are plotted. In FIG. 7, the vertical axis represents the surface temperature during printing (° C.), and the horizontal axis represents the number of scans (times).

In either case, the optimum surface temperature during printing decreases as the number of scans increases. Therefore, when the printing mode is selected, an image having good image density, color bleeding, and beading can be obtained by setting the surface temperature during printing according to the number of scans and performing printing.
Further, by using an ink having a mass change rate of up to 25% by mass of the ink and having a mass change rate of 0.2% by mass / min or more, the drying property is improved and an optimum image can be obtained at a low temperature.

(FIGS. 1 and 2)
201 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge case (FIGS. 3 and 4)
DESCRIPTION OF SYMBOLS 101 Main body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading part 105 Operation part 131 Guide rod 132 Sub guide rod 133 Carriage 134 Recording head 135 Sub tank 141 Paper loading part 142 Paper 143 Paper feed roller 152 Guide roller 154 Counter roller 157 Feed roller 161 Guide member 171 Spur roller 172 Discharge roller 173 Spur roller 181 Hot air heater 182 Infrared heater 183 Back heater 184 Heater during printing

JP 2005-220352 A JP 2011-094082 A JP 2005-161814 A

Claims (5)

In an image recording method for forming an image by attaching ink onto a non-porous recording medium by ejecting ink from a nozzle,
A printing step of forming an image by adhering the ink with a surface temperature on the recording surface side of the non-porous recording medium in a range of 40 ° C. or more and 60 ° C. or less;
A drying process for heating and fixing images that have not been fixed;
Have
The ink contains at least water, a water-soluble organic solvent, a colorant, and resin fine particles,
The water-soluble organic solvent does not contain a solvent having a boiling point of more than 250 ° C.,
In the printing step, the surface temperature of the non-porous recording medium is lowered according to an increase in the number of print scans. The ink is an ink having an ink exposed surface area of 5 mg / mm ² , an ink having a mass change rate up to 25% at 25 ° C. and 10% RH or less up to 25% by mass / min. The image recording method according to claim 1.   3. The image recording method according to claim 1, wherein 50% by mass or more of the water-soluble organic solvent is a water-soluble organic solvent having a boiling point of 200 ° C. or less.   The image recording method according to claim 1, wherein the water-soluble organic solvent contains 2,3-butanediol.   An image recording apparatus that records an image by the image recording method according to claim 1.