JP2010208344A - Inkjet image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet image forming method by which an image is formed by using inkjet ink enabling printing on various recording media and that is excellent in strike-through resistance, printed image quality and image preservability and is improved in dispersion stability and emission stability. <P>SOLUTION: In the inkjet image forming method, the image is formed by emitting the inkjet ink from an inkjet recording head onto the recording medium. The inkjet ink contains at least an oil gelling agent and has phase transition temperature of ≥30°C and <100°C and penetration measured according to a method specified by JIS K 2207-1996 is between 1 and 100 (however, temperature of 20°C and load of 10 kg are adopted as measuring conditions). The inkjet image forming method is characterized in that the inkjet ink heated at 35 to 100°C is emitted onto the recording medium to form the image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel ink-jet ink and ink-jet recording method, and more specifically, can be printed on various recording media, has excellent anti-through-through resistance, printed image quality, and storability, and ink dispersion stability and emission stability. The present invention relates to an ink jet image forming method for forming an image using an ink jet ink having improved properties.

  In recent years, the ink jet recording system can create images easily and inexpensively, and thus has been applied to various printing fields such as photographs, various printing, marking, and special printing such as color filters. In particular, a recording device that emits and controls fine dots, ink that has improved color reproduction gamut, durability, and emission suitability, and ink absorbability, coloring material color development, surface gloss, etc. have been dramatically improved. It is also possible to obtain image quality comparable to silver halide photography using special paper. The image quality improvement of today's ink jet recording system is achieved only when all of the ink jet recording apparatus, ink jet ink, and special paper are available.

  However, in an inkjet system that requires special paper, there is a problem that the recording medium that can be used is limited, the cost of the recording medium is increased, and the like.

  On the other hand, in the office, there is an increasing need for a system that can perform high-speed full-color printing without being restricted by a recording medium (for example, plain paper, coated paper, art paper, plain paper double-sided printing, etc.). In the electrophotographic system, there is a high-speed type capable of printing 100 sheets at an A4 size per minute, but the printing is limited to monochrome images, and the printing speed is increased in color printing, the simplicity of the apparatus, the cost, In order to satisfy any requirement such as power consumption, there are still many technical problems, and the user's request has not been satisfied.

  For example, when a general water-based dye ink or water-based pigment ink is used in a high-speed printing method using plain paper, many of these inks have a surface tension reduced by adding a surfactant or the like. This ink is very easily penetrated into a recording medium such as paper, and as a result, feathering or ink penetration that penetrates to the back side of the recording medium is caused. In some water-based dye black inks and water-based pigment black inks, the surface tension is set to be higher than the critical surface tension of plain paper, and the penetration speed to plain paper is suppressed, so that the black ink that constitutes black characters etc. Although attempts have been made to increase the sharpness of the dot outline, this method has a problem that the drying and fixing speed of the landed ink droplets is slow and is not suitable for high-speed recording.

  In addition, when image fixing is performed using water-based dye ink or water-based pigment ink, a plain paper whose support itself has an ink absorption capability or an exclusive inkjet paper having an ink absorption layer on the support is required. In a recording medium such as coated paper that does not have an ink absorbing layer, ink droplet repelling, ink drying failure and fixing failure are caused, and image recording becomes substantially difficult.

  Based on the above problems, a method for recording an image on various recording media different from dedicated paper by an ink jet recording method has been proposed. For example, a phase change ink jet method using a wax ink solid at room temperature, a solvent ink jet method using an ink mainly composed of a fast-drying organic solvent, or crosslinking by irradiation with an actinic ray, for example, ultraviolet (UV) light after recording. For example, an ultraviolet inkjet method.

  For example, an ink jet ink containing an organic solvent, a colorant, and an ultraviolet curable composition is printed on a polyethylene terephthalate film, a vinyl chloride sheet, etc., cured by irradiating ultraviolet rays with an ultraviolet irradiation device, and ink fixing by touch dry evaluation A technique for improving the solvent resistance by evaluating methanol rubbing is disclosed (for example, see Patent Document 1). However, from the viewpoint that it is not desired to cure the ink in the vicinity of the recording head surface, it is possible to apply it onto a recording medium. There is a method in which a certain period of time is provided between the ink ejection and the ultraviolet irradiation by the ultraviolet irradiation device. However, when these structures are applied to plain paper printing, the ink is discharged during the time lag from ink landing to ultraviolet irradiation. The problem is that normal paper cannot be printed due to penetration of plain paper, feathering and ink back-through. A.

  On the other hand, there is known a method in which a normal temperature solid ink containing a low melting point wax is heated (for example, 120 ° C. or higher), melted, ejected in the melted state, and instantly solidified on a recording medium. According to this method, it is possible to obtain an image having a moderate quality even with a recording medium having ink absorbing ability such as plain paper, but in order to increase the scratch resistance of the formed image, the hardness of the solidified ink is reduced. Although it is necessary to increase, it is necessary to use a wax having a high melting point in order to obtain a desired hardness. For example, when a wax having a melting point of 120 ° C. or higher is used, the head is heated to a high temperature of 120 ° C. or higher, so that the heat resistance of the head of the ink jet printing apparatus and the members of the ink supply system are overloaded, making the printing apparatus difficult to be durable. There is a problem that the apparatus must be large. In particular, in a system using a piezo element for the recording head, there is a Curie temperature as a high temperature limit point, and there is an upper limit on the temperature that can be heated by itself.

  In addition, ink containing alkylarylcycloalkanol as a gelling agent in the ink, and using solid ink that emits at a temperature equal to or higher than the melting point or phase transition point of the gelling agent, resolution, water resistance, between the ink color dots Has been disclosed (see, for example, Patent Document 2). However, in the above proposed method, the ink hardness at the time of curing is small, and the fixing property, the holding power of the image against temperature and pressure are insufficient. Furthermore, it has not yet achieved a quality that satisfies the feathering resistance and back-through resistance when printed on plain paper, etc., the bleeding resistance during high-temperature storage, or the ink back-off resistance when stored repeatedly after printing. Is the current situation.

  Moreover, a technique for forming a gel electrolyte by adding a gelling agent to an electrolyte of a photoelectric conversion element to prevent a decrease in photocurrent density is disclosed (for example, see Patent Document 3). No mention is made of the application of.

  In addition, hot melt ink containing a (meth) acrylic acid copolymer having a weight average molecular weight of 500 to 30,000 is heated to 120 ° C. and applied to plain paper, bending resistance, rubbing resistance, and copy paper feeding compatibility A technique for improving the performance is disclosed (for example, see Patent Document 4). Since it is heated to a high temperature of 120 ° C. in the same manner as described above, the heat resistance of the head of the ink jet printing apparatus and the members of the ink supply system are loaded, and the durability of the apparatus is difficult. In addition, when printing on coated paper, there is a problem of degradation of image rubbing that is presumed to be derived from the shape of ink rising at the time of droplet landing.

JP 2002-241654 A JP-A-11-315245 Japanese Patent Laid-Open No. 11-185836 JP 2000-72992 A

  The present invention has been made in view of the above problems, and its object is to enable printing on various recording media, excellent anti-through-through resistance, printed image quality, and image storage stability, and ink dispersion stability and emission. It is an object of the present invention to provide an ink jet image forming method for forming an image using an ink jet ink having improved stability.

The above object of the present invention is achieved by the following configurations.
(Claim 1)
It contains at least an oil gelling agent, has a phase transition temperature of 30 ° C. or higher and lower than 100 ° C., and has a penetration of 1 or more and 100 or less measured according to the method defined in JIS K 2207-1996. An inkjet image forming method for forming an image by ejecting an inkjet ink (with a temperature of 20 ° C. and a load of 10 g as measurement conditions) onto a recording medium from an inkjet recording head, the inkjet ink being 35 An inkjet image forming method, wherein an image is formed by discharging onto the recording medium while heating to -100 ° C.

  Moreover, a preferable embodiment is shown below.

  1) Ink jet ink used for ink jet recording contains at least an oil gelling agent, its phase transition temperature is 30 ° C. or higher and lower than 100 ° C., and further measured according to the method specified in JIS K 2207-1996 An ink-jet ink characterized by having a penetration of 1 or more and 100 or less (however, the measurement conditions are a temperature of 20 ° C. and a load of 10 g).

  2) The inkjet ink according to 1), wherein the content of the oil gelling agent is 0.1% by mass or more and 30% by mass or less.

  3) The ink-jet ink according to 1) or 2), wherein the total solid component amount at 20 ° C. is 3.0% by mass or more and 15% by mass or less.

  4) The ink-jet ink according to any one of 1) to 3), wherein the ink-jet ink contains a pigment and a pigment dispersant.

  5) The inkjet ink according to 4), wherein the pigment has an average dispersed particle size of 50 nm or more and 150 nm or less.

  6) The inkjet ink according to any one of 1) to 5), wherein the inkjet ink contains an actinic ray curable composition that is cured by actinic rays.

  7) The inkjet ink according to 6), wherein the actinic ray curable composition is a cationic polymerizable composition.

  8) The inkjet ink according to 6) or 7), wherein the inkjet ink contains at least one photopolymerization initiator.

  9) An inkjet recording method for recording on a recording medium using the inkjet ink according to any one of 1) to 5), wherein the heated inkjet ink is applied to the recording medium from the inkjet recording head. An ink jet recording method, wherein the ink jet ink thus landed is gelled and fixed by being landed on the substrate and then cooled.

  10) An inkjet recording method for recording on a recording medium using the inkjet ink according to any one of 6) to 8), comprising two or more fixing means for the inkjet ink, An ink jet recording method, wherein at least one of the immobilization means is an immobilization means by gelation.

  11) The inkjet recording method according to 10), wherein the immobilization means is at least an immobilization means by gelation and an immobilization means by irradiation with actinic rays.

  According to the present invention, by using ink-jet ink that can be printed on various recording media, has excellent through-through resistance, printed image quality, image storage stability, and improved ink dispersion stability and emission stability. An ink jet image forming method for forming an image can be provided.

1 is a front view illustrating a configuration of a main part of an ink jet recording apparatus that can be used in the present invention. FIG. 2 is a top view illustrating an example of a configuration of a main part of a line head type ink jet recording apparatus that can be used in the present invention.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

  As a result of intensive studies in view of the above problems, the inventors of the present invention contain at least an oil gelling agent, a phase transition temperature of 30 ° C. or higher and lower than 100 ° C., and further specified by JIS K 2207-1996. Ink jet ink having a penetration of 1 or more and 100 or less (provided that the measurement conditions are a temperature of 20 ° C. and a load of 10 g) is ejected from the inkjet recording head onto a recording medium. An ink jet image forming method for forming an image, wherein the ink jet ink is heated to 35 to 100 ° C. and ejected onto the recording medium to form an image. It can print on media, has excellent resistance to see-through, print image quality and storability, and ink dispersion stability and ejection stability ( Hereinafter, it has been found that an inkjet image forming method for forming an image using an inkjet ink with improved “emission” (also referred to as “ejection”) can be realized.

  The ink of the present invention is an ink that enables sol-gel transition by adding an oil gelling agent. Furthermore, the sol-gel phase transition temperature (phase transition temperature) can be easily controlled between the ink temperature at the time of ink ejection and the ink temperature after landing on the recording medium or the like.

  That is, the ink of the present invention has a low viscosity and good fluidity when ejected. However, after landing on the recording medium, the ink temperature drops instantaneously due to the printing environment temperature to form a gel, and the fluidity of the ink is remarkably reduced, so that plain paper with high ink absorption is used as the recording medium. However, the permeability of the ink is suppressed, and as a result, even with a relatively low surface tension ink that can be recorded on art paper or coated paper, it is considered that feathering and back-through have been dramatically improved. .

  Details of the present invention will be described below.

  One of the features of the ink-jet ink of the present invention (hereinafter also simply referred to as ink) is that it contains at least an oil gelling agent.

  The gel referred to in the present invention means that the solute has independent mobility due to the interaction such as lamellar structure, polymer network formed by covalent bond or hydrogen bond, polymer network formed by physical aggregation, and aggregate structure of fine particles. It has a structure that has been lost and assembled, and is a solidified or semi-solidified state with a sudden increase in viscosity and a significant increase in elasticity.

  The oil referred to in the present invention is a general term for compounds other than water, and the oil gelling agent according to the present invention refers to a compound that can form the gel when added to a compound other than water.

  In general, a gel becomes a fluid solution (sometimes called a sol) by heating, a thermoreversible gel that returns to the original gel when cooled, and once gelled, it can be reheated even if heated. There is a heat irreversible gel that does not return. The gel formed by the oil gelling agent according to the present invention is preferably a thermoreversible gel.

  In the ink of the present invention containing the oil gelling agent according to the present invention, one of the characteristics is that the phase transition temperature of the ink is 30 ° C. or higher and lower than 100 ° C., and 40 ° C. or higher and 80 ° C. or lower. Preferably there is. When the phase transition temperature of the ink is less than 30 ° C., it is difficult to obtain a stable ejection property due to the influence of the printing environment temperature when ejecting ink droplets from the recording head. As a result, it is necessary to heat the printer to an excessively high temperature, which imposes a load on the head of the ink jet recording apparatus and the members of the ink supply system, causing a problem in durability, and increasing the overall size of the apparatus and resulting cost increase. It becomes.

  In order to realize the phase transition temperature of the ink defined above, it is preferable to select a compound having a melting point of 20 to 250 ° C., more preferably a compound having a temperature of 40 to 90 ° C. as the oil gelling agent. It is.

  The phase transition temperature by the sol-gel referred to in the present invention means a temperature at which the viscosity suddenly changes from a fluid solution state to a gel state, and the gel transition temperature, gel dissolution temperature, gel softening temperature, It is synonymous with terms called sol-gel transition point and gel point.

  The method for measuring the phase transition temperature of the ink is, for example, a method in which a small iron piece sealed in a glass tube is placed in an dilatometer and the phase transition point is a point at which the ink liquid does not naturally fall in response to a temperature change ( J. Polym. Sci., 21, 57 (1956)), a method in which an aluminum cylinder is placed on ink and the temperature at which the aluminum cylinder naturally falls when the gel temperature is changed is measured as a phase transition temperature ( Journal of the Japanese Society of Rheology, Vol. 17, 86 (1989)). As a simple method, place a gel-like test piece on the heat plate, heat the heat plate, measure the temperature at which the shape of the test piece collapses, and obtain this as the sol-gel phase transition temperature. Can do.

  The oil gelling agent used in the ink of the present invention may be a high molecular compound or a low molecular compound, but is preferably a low molecular compound from the viewpoint of use in ink. Moreover, as the gel structure, a compound in which the oil gelling agent itself can form a fibrous aggregate is preferable. Formation of the fibrous aggregate can be easily confirmed by morphological observation with a transmission electron microscope.

  Specific examples of the oil gelling agent that can be used in the ink of the present invention are shown below, but the present invention is not limited only to these compounds.

  The compounds preferably used in the oil gelling agent are OG-1, OG-2, OG-5 and OG-15.

  In the ink of the present invention, the content of the oil gelling agent according to the present invention is preferably 0.1 to 30% by mass, more preferably 0.3 to 15% by mass with respect to the total mass of the ink, It is particularly preferably 3 to 15% by mass. When the content of the oil gelling agent is in the range of 0.1 to 30% by mass, more stable emission characteristics can be obtained, and the object and effects of the present invention can be further exhibited. In particular, when a pigment is used as the coloring material, the oil gelling agent may impair the dispersion stability of the pigment, and therefore the content of the oil gelling agent is preferably in the range of 0.1 to 30% by mass.

  In the ink of the present invention, the total amount of solid components at 20 ° C. is preferably 3.0% by mass or more and 15% by mass or less.

  The total solid component amount as used in the present invention means the total amount of components in a solid state at 20 ° C. among the materials constituting the ink. For example, the oil gelling agent according to the present invention having a melting point of 20 ° C. or higher, Solid components such as pigment particles described later are included.

  In the ink of the present invention, when the total solid component amount at 20 ° C. is in the range of 3.0% by mass or more and 15% by mass or less, clogging is not caused at the time of ink ejection, and stable ejection characteristics can be obtained. Can do.

  The ink-jet ink of the present invention is characterized in that the penetration at a load of 10 g measured according to the method defined in JIS K 2207-1996 at 20 ° C. is 1 or more and 100 or less.

  The penetration (20 ° C.) in the present invention is a value measured according to the method defined in JIS K 2207-1996 except that only the load is changed to 10 g.

  As a specific measuring method, 10 g is applied to the needle having the shape shown in FIG. 2 in which the balance is maintained under a load of 0 g using the penetration test apparatus shown in FIG. 1 of JIS K 2207-1996. Apply a load of ± 0.1 g. On the other hand, after placing the ink-jet ink as a specimen in a glass container and keeping the temperature at 20 ± 0.1 ° C., the needle is vertically penetrated into the ink-jet ink surface together with the holding device and the weight, and the tip of the needle and the ink surface The penetration distance (mm) 5 seconds after the contact with is measured with a displacement difference meter (dial gauge), and a value obtained by multiplying the obtained value by 10 is defined as penetration (20 ° C.).

  The penetration (20 ° C.) according to the present invention measured according to the above method is 1 or more and 100 or less, preferably 20 or more and 80 or less.

  When the penetration (20 ° C.) specified in the present invention exceeds 100, sufficient character quality and back-through resistance cannot be obtained when recording on plain paper. It is not preferable because it breaks down.

  In the ink of the present invention, the method for achieving the penetration (20 ° C.) defined above is not particularly limited, but in the present invention, the type (melting point, etc.) of the oil gelling agent and the addition amount are selected. By performing the adjustment, an ink having a desired penetration can be obtained.

  Next, each component excluding the above items of the inkjet ink of the present invention will be described.

  In the ink of the present invention, a dye or a pigment can be used without limitation as a color material constituting the ink, but a pigment having good dispersion stability with respect to the ink component and excellent weather resistance is used. It is preferable. Although it does not necessarily limit as a pigment, For example, the organic or inorganic pigment of the following number described in a color index can be used for this invention.

  Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, and 53: 1. 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144, 146 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13 16, 20, 36, blue or cyan pigments include Pigment Blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 1 7-1, 22, 27, 28, 29, 36, 60, as green pigment, Pigment Green 7, 26, 36, 50, as yellow pigment, Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193, and black pigments such as Pigment Black 7, 28, 26 can be used depending on the purpose.

  Specific product names include, for example, chromofine yellow 2080, 5900, 5930, AF-1300, 2700L, chromofine orange 3700L, 6730, chromofine scarlet 6750, chromofine magenta 6880, 6886, 6891N, 6790, 6887. , Chromofine Violet RE, Chromofine Red 6820, 6830, Chromofine Blue HS-3, 5187, 5108, 5197, 5085N, SR-5020, 5026, 5050, 4920, 4927, 4937, 4824, 4933GN-EP, 4940, 4973, 5205, 5208, 5214, 5221, 5000P, Chromofine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Ku Mofine Black A-1103, Seika Fast Yellow 10GH, A-3, 2035, 2054, 2200, 2270, 2300, 2400 (B), 2500, 2600, ZAY-260, 2700 (B), 2770, Seika Fast Red 8040 , C405 (F), CA120, LR-116, 1531B, 8060R, 1547, ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, Seika Fast Carmine 6B1476T-7, 1483LT, 3840, 3870 , Seika Fast Bordeaux 10B-430, Seica Light Rose R40, Seika Light Violet B800, 7805, Seika Fast Maroon 460N, Seika Fast Orange 900, 2900, Seika Light Blue C7 18, A612, cyanine blue 4933M, 4933GN-EP, 4940, 4973 (manufactured by Dainichi Seika Kogyo), KET Yellow 401, 402, 403, 404, 405, 406, 416, 424, KET Orange 501, KET Red 301, 302 , 303, 304, 305, 306, 307, 308, 309, 310, 336, 337, 338, 346, KET Blue 101, 102, 103, 104, 105, 106, 111, 118, 124, KET Green 201 (large Nippon Ink Chemical Co., Ltd.), Colortex Yellow 301, 314, 315, 316, P-624, 314, U10GN, U3GN, UNN, UA-414, U263, Finecol Yellow T-13, T-05, Pi gment Yellow 1705, Colortex Orange 202, Colortex Red 101, 103, 115, 116, D3B, P-625, 102, H-1024, 105C, UFN, UCN, UBN, U3BN, URN, UGN, UG276, U456, U457, C USN, Colortex Maroon 601, Colortex Brown B610N, Colortex violet 600, Pigment Red 122, Colortex Blue 516, 517, 518, 519, A818, P-908, 510, Colortex Green 402, 403B, Col. , Lionol lue FG7330, FG7350, FG7400G, FG7405G, ES, ESP-S (manufactured by Toyo Ink), Toner Magenta E02, Permanent RubinF6B, Toner Yellow HG, Permanent Yellow GG-02, Black Bumpy Carbon G2 , # 2400, # 2350, # 2200, # 1000, # 990, # 980, # 970, # 960, # 950, # 850, MCF88, # 750, # 650, MA600, MA7, MA8, MA11, MA100, MA100R , MA77, # 52, # 50, # 47, # 45, # 45L, # 40, # 33, # 32, # 30, # 25, # 20, # 10, # 5, # 44, And the like, such as F9 (manufactured by Mitsubishi Chemical).

  Further, it is also possible to use a dispersion liquid in which the pigment is dispersed in high concentration in advance in water, a solvent, a polymerizable monomer or the like.

  In the ink of the present invention, it is preferable to use a pigment dispersant for dispersing the pigment. Examples of the dispersant that can be used in the present invention include higher fatty acid salts, alkyl sulfates, alkyl ester sulfates, alkyl sulfonates, sulfosuccinates, naphthalene sulfonates, alkyl phosphates, and polyoxyalkylene alkyls. Activators such as ether phosphate, polyoxyalkylene alkylphenyl ether, polyoxyethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, polyoxyethylene fatty acid amide, amine oxide, or styrene, styrene derivatives, vinyl naphthalene derivatives, Block copolymer consisting of two or more monomers selected from acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid derivatives, random copolymer Body and can their salts.

  For the dispersion of the pigment, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, a paint shaker, or the like can be used. It is also possible to add a dispersant when dispersing the pigment.

  In the present invention, the addition amount of the pigment dispersant is preferably 10 to 100% by mass with respect to the pigment.

  The average dispersed particle size of the pigment obtained by the above method is preferably 50 nm or more and 150 nm or less. If the average dispersed particle size of the pigment is within the range specified above, the dispersion stability of the ink can be improved. As a result, clogging of the head nozzle is suppressed, and the emission stability is further improved. With the improvement of transparency, the curing efficiency of actinic rays when an actinic ray curable composition described later is contained can be increased.

  In the ink of the present invention, the means for adjusting the average dispersed particle size of the pigment to the range specified above is achieved by, for example, appropriately selecting or combining pigment, dispersant, dispersion medium selection, dispersion conditions, and filtration conditions. can do.

  In the ink of the present invention, conventionally known dyes, preferably oil-soluble dyes, can be used as required.

  Specific examples of oil-soluble dyes that can be used in the present invention are given below, but the present invention is not limited to these.

<Magenta dye>
MS Magenta VP, MS Magenta HM-1450, MS Magenta HSo-147 (manufactured by Mitsui Toatsu Co., Ltd.), AIZENSOT Red-1, AIZEN SOT Red-2, AIZEN SOTRed-3, AIZEN SOT Pink-1, EPIRON Red GE SPECIAL (above, manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN Red FB 200%, MACROLEX Red Violet R, MACROLEX ROT5B (above, manufactured by Bayer Japan), KAYASET Red B, KAYASET Red 130, KAYASET Red Japan 802 ), PHLOXIN, ROSE BENGAL, ACID Red (above, made by Daiwa Kasei), HSR-31, DIARESIN Red K (below) , Manufactured by Mitsubishi Kasei Co., Ltd.), Oil Red (manufactured by BASF Japan Co., Ltd.).

<Cyan dye>
MS Cyan HM-1238, MS Cyan HSo-16, Cyan HSo-144, MS Cyan VPG (manufactured by Mitsui Toatsu Co., Ltd.), AIZEN SOT Blue-4 (manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN BR. Blue BGLN 200%, MACROLEX Blue RR, CERES Blue GN, SIRIUS SUPRATURQ. Blue Z-BGL, SIRIUS SUTRA TURQ. Blue FB-LL 330% (above, Bayer Japan), KAYASET Blue FR, KAYASET Blue N, KAYASET Blue 814, Turq. Blue GL-5 200, Light Blue BGL-5 200 (above, Nippon Kayaku Co., Ltd.), DAIWA Blue 7000, Oleosol Fast Blue GL (above, Daiwa Kasei), DIARESIN Blue P (Mitsubishi Kasei), SUDAN Blue 670, NEOPEN Blue 808, ZAPON Blue 806 (above, manufactured by BASF Japan).

<Yellow dye>
MS Yellow HSm-41, Yellow KX-7, Yellow EX-27 (Mitsui Toatsu), AIZEN SOT Yellow-1, AIZEN SOT YellowW-3, AIZEN SOT Yellow-6 (above, manufactured by Hodogaya Chemical Co., Ltd.), MACROLEX Yellow 6G, MACROLEX FLUOR. Yellow 10GN (above, manufactured by Bayer Japan), KAYASET Yellow SF-G, KAYASET Yellow 2G, KAYASET Yellow AG, KAYASET Yellow EG (above, manufactured by Nippon Kayaku Co., Ltd.), Daiwa Yellow 330H HSY-68 (manufactured by Mitsubishi Kasei Co., Ltd.), SUDAN Yellow 146, NEOPEN Yellow 075 (above, manufactured by BASF Japan).

<Black dye>
MS Black VPC (Mitsui Toatsu Co., Ltd.), AIZEN SOT Black-1, AIZEN SOT Black-5 (above, Hodogaya Chemical Co., Ltd.), RESORIN Black GSN 200%, RESOLIN Black BS (above, Bayer Japan Co., Ltd.), KAYASET Black A-N (manufactured by Nippon Kayaku Co., Ltd.), DAIWA Black MSC (manufactured by Daiwa Kasei Co., Ltd.), HSB-202 (manufactured by Mitsubishi Kasei Co., Ltd.), NEPTUNE Black X60, NEOPEN Black X58 (manufactured by BASF Japan) .

  The amount of pigment or oil-soluble dye added is preferably 0.1 to 20% by mass, more preferably 0.4 to 10% by mass. If it is 0.1% by mass or more, good image quality can be obtained, and if it is 20% by mass or less, an appropriate ink viscosity in ink ejection can be obtained. In addition, two or more kinds of colorants can be mixed as appropriate for color adjustment.

  The ink of the present invention preferably contains an actinic ray curable composition that cures with actinic rays together with an oil gelling agent and a colorant.

  The actinic ray curable composition (hereinafter also referred to as a photopolymerizable compound) used in the present invention will be described.

  In the present invention, the photopolymerizable compound can be used without any particular limitation. Among them, a photocationically polymerizable compound or a radically polymerizable compound is preferably used, and a photocationically polymerizable compound is particularly preferable.

  As the photo cationic polymerizable monomer, various known cationic polymerizable monomers can be used. For example, the epoxies exemplified in JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, JP-A-2001-220526 Compounds, vinyl ether compounds, oxetane compounds and the like.

  In the present invention, for the purpose of suppressing the shrinkage of the recording medium during ink curing, it contains at least one oxetane compound as a photopolymerizable compound and at least one compound selected from an epoxy compound and a vinyl ether compound. Is preferred.

  A preferable aromatic epoxide is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, such as bisphenol A or an alkylene oxide thereof. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or alkylene oxide adducts thereof, and novolak type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is preferable.

  Preferred aliphatic epoxides include di- or polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or Diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or alkylene oxide adduct thereof, polyethylene glycol or alkylene oxide adduct thereof Of polyalkylene glycols such as diglycidyl ether, polypropylene glycol or diglycidyl ether of its alkylene oxide adduct Glycidyl ether, and the like. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  Among these epoxides, in view of fast curability, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are particularly preferable. In the present invention, one of the epoxides may be used alone, or two or more may be used in appropriate combination.

  Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl Pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -O- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.

  Among these vinyl ether compounds, in consideration of curability, adhesion, and surface hardness, di- or trivinyl ether compounds are preferable, and divinyl ether compounds are particularly preferable. In the present invention, one of the above vinyl ether compounds may be used alone, or two or more thereof may be used in appropriate combination.

  The oxetane compound according to the present invention is a compound having an oxetane ring, and any known oxetane compound as introduced in JP-A Nos. 2001-220526 and 2001-310937 can be used.

  In the oxetane compound according to the present invention, when a compound having 5 or more oxetane rings is used, the viscosity of the ink composition becomes high, so that handling becomes difficult, and the glass transition temperature of the ink composition becomes high. The resulting cured product will not be sufficiently sticky. The compound having an oxetane ring used in the present invention is preferably a compound having 1 to 4 oxetane rings.

  Hereinafter, although the specific example of the compound which has an oxetane ring based on this invention is demonstrated, this invention is not limited to these.

  An example of the compound having one oxetane ring is a compound represented by the following general formula (1).

In the general formula (1), R ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, or an aryl group. , Furyl group or thienyl group. R ² represents an alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 2-methyl- C2-C6 alkenyl group such as 2-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, phenyl group, benzyl group, fluorobenzyl group, methoxybenzyl group, phenoxyethyl group, etc. A group having an aromatic ring, an alkylcarbonyl group having 2 to 6 carbon atoms such as an ethylcarbonyl group, a propylcarbonyl group, and a butylcarbonyl group, an alkylcarbonyl group having 2 to 6 carbon atoms such as an ethoxycarbonyl group, a propoxycarbonyl group, and a butoxycarbonyl group; Alkoxycarbonyl group, ethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group, pentylcarbamoyl An N-alkylcarbamoyl group having 2 to 6 carbon atoms, such as a group; As the oxetane compound used in the present invention, it is particularly preferable to use a compound having one oxetane ring because the resulting composition has excellent tackiness, low viscosity and excellent workability.

  An example of a compound having two oxetane rings includes a compound represented by the following general formula (2).

In the general formula (2), R ¹ is the same group as that in the general formula (1). R ³ is, for example, a linear or branched poly (alkyleneoxy) group such as a linear or branched alkylene group such as an ethylene group, a propylene group or a butylene group, a poly (ethyleneoxy) group or a poly (propyleneoxy) group. ) Group, propenylene group, methylpropenylene group, butenylene group or other linear or branched unsaturated hydrocarbon group, alkylene group containing carbonyl group or carbonyl group, alkylene group containing carboxyl group, alkylene containing carbamoyl group Group.

As the R ^3, the following general formula (3) can also include polyvalent group selected from groups represented by (4) and (5).

In the general formula (3), R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, a methoxy group, an ethoxy group, a propoxy group, or a butoxy group. An alkoxy group having 1 to 4 carbon atoms, a halogen atom such as a chlorine atom or a bromine atom, a nitro group, a cyano group, a mercapto group, a lower alkyl carboxyl group, a carboxyl group, or a carbamoyl group.

In the general formula (4), R ⁵ represents an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C (CF ₃ ) ₂ , or C (CH ₃ ) ₂ .

In General formula (5), R < ⁶ > is a C1-C4 alkyl group, such as a methyl group, an ethyl group, a propyl group, a butyl group, or an aryl group. n is an integer of 0-2000. R ⁷ is a methyl group, an ethyl group, a propyl group, a butyl group having 1 to 4 carbon atoms, or an aryl group. R ⁷ may further include a group selected from the group represented by the following general formula (6).

In the general formula (6), R ⁸ is a methyl group, an ethyl group, a propyl group, butyl alkyl group having 1 to 4 carbon atoms such as a group, or an aryl group. m is an integer of 0-100.

  Specific examples of the compound having two oxetane rings include the following compounds.

Exemplary compound 1 is a compound in which R ¹ is an ethyl group and R ³ is a carboxyl group in the general formula (2). Exemplary compound 2 is a compound in which, in the general formula (2), R ¹ is an ethyl group, R ³ is the general formula (5), R ⁶ and R ⁷ are methyl groups, and n is 1.

Among the compounds having two oxetane rings, preferred examples other than the above compounds include compounds represented by the following general formula (7). In general formula (7), ^{R 1} has the same meaning as ^{R 1} in the general formula (1).

  An example of a compound having 3 to 4 oxetane rings is a compound represented by the following general formula (8).

In the general formula (8), ^{R 1} is the same meaning as ^{R 1} in the general formula (1). As R ⁹ , for example, a branched alkylene group having 1 to 12 carbon atoms such as groups represented by the following A to C, a branched poly (alkyleneoxy) group such as a group represented by the following D, or the following E And branched polysiloxy groups such as those shown. j is 3 or 4.

In the above A, R ¹⁰ is a lower alkyl group such as a methyl group, an ethyl group, or a propyl group. Moreover, in said D, p is an integer of 1-10.

  Illustrative compound 3 is an example of a compound having 3 to 4 oxetane rings.

  Furthermore, examples of the compound having 1 to 4 oxetane rings other than those described above include compounds represented by the following general formula (9).

In the general formula (9), ^{R 8} has the same meaning as ^{R 8} in the general formula (6). R ¹¹ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or a trialkylsilyl group, and r is 1 to 4.

  Preferable specific examples of the oxetane compound used in the present invention include the following compounds.

  The method for producing each compound having an oxetane ring described above is not particularly limited, and may be a conventionally known method, for example, Pattisson (DB Pattison, J. Am. Chem. Soc., 3455, 79). (1957)) discloses a method for synthesizing an oxetane ring from a diol. In addition to these, compounds having 1 to 4 oxetane rings having a high molecular weight of about 1000 to 5000 are also included. Examples of these specific compounds include the following compounds.

  Next, the radical polymerizable compound will be described.

  In the ink of the present invention, the use of the radical polymerizable compound is not limited. Examples of the radical polymerizable compound include JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, A photocurable material using a photopolymerizable composition described in JP-A-10-863 and a cationic polymerization type photocurable resin are known, and recently, a long wavelength longer than visible light. Photo-cationic polymerization type photo-curing resins sensitized to the region are also disclosed in, for example, JP-A-6-43633 and JP-A-8-324137.

  The radical polymerizable compound is a compound having an ethylenically unsaturated bond capable of radical polymerization, and may be any compound as long as it has at least one ethylenically unsaturated bond capable of radical polymerization in the molecule. , Oligomers, polymers and the like having a chemical form. Only one kind of radically polymerizable compound may be used, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve desired properties.

  The ink of the present invention preferably contains at least one photopolymerization initiator.

  Photopolymerization initiators can be broadly classified into two types: intramolecular bond cleavage type and intramolecular hydrogen abstraction type.

  Examples of the intramolecular bond cleavage type photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2. -Hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino (4 Acetophenones such as -thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone; benzoins such as benzoin, benzoin methyl ether, benzoin isopropyl ether; 2 , 4,6-Trimethylbenzoindiphenyl Scan fins oxides such acylphosphine oxide of benzil, methyl phenylglyoxylate esters.

  On the other hand, as an intramolecular hydrogen abstraction type photopolymerization initiator, for example, benzophenone, methyl 4-phenylbenzophenone, o-benzoylbenzoate, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl Benzophenones such as diphenyl sulfide, acrylated benzophenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 3,3'-dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2 Thioxanthone series such as 1,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone; amino benzophenone series such as Michler-ketone, 4,4'-diethylaminobenzophenone; 10-butyl- - chloro acridone, 2-ethyl anthraquinone, 9,10-phenanthrenequinone, camphorquinone, and the like.

  The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 10.00% by mass of the actinic ray curable composition.

  Examples of radical polymerization initiators include triazine derivatives described in JP-B-59-1281, JP-B-61-9621, JP-A-60-60104, JP-A-59-1504, and JP-A-59-1504. Organic peroxides described in JP-A-61-243807, JP-B-43-23684, JP-B-44-6413, JP-B-44-6413, JP-B-47-1604, etc., and the United States Diazonium compounds described in Japanese Patent No. 3,567,453, organic azides described in US Pat. Nos. 2,848,328, 2,852,379 and 2,940,853 Compounds, ortho-quinonediazides described in JP-B 36-22062, JP-B 37-13109, JP-B 38-18015, JP-B 45-9610 and the like, Various onium compounds described in JP-A-55-39162, JP-A-59-14023, and the like, and “Macromolecules, Vol. 10, page 1307 (1977); No. 142205, JP-A-1-54440, European Patent No. 109,851, European Patent No. 126,712, etc., “Journal of Imaging Science” (J. Imag. Sci.), Vol. 30, page 174 (1986), (oxo) sulfonium organoboron complexes described in Japanese Patent Nos. 2711491 and 2803454, 61-151197, titanocenes, “Coordination Chemistry Levi A transition metal complex containing a transition metal such as ruthenium described in (Coordination Chemistry Review), 84, 85-277 (1988) and JP-A-2-182701, No. 2,4,5-triarylimidazole dimer, carbon tetrabromide, and organic halogen compounds described in JP-A-59-107344. These polymerization initiators are preferably contained in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the compound having an ethylenically unsaturated bond capable of radical polymerization.

  In the ink of the present invention, a photoacid generator can also be used.

  As the photoacid generator, for example, a chemically amplified photoresist or a compound used for photocationic polymerization is used (edited by Organic Electronics Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), 187. To page 192). Examples of compounds suitable for the present invention are listed below.

First, diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, SbF 6 -, CF 3 SO 3 - and salts be able to.

  Specific examples of onium compounds that can be used in the present invention are shown below.

  Secondly, sulfonated substances that generate sulfonic acid can be mentioned, and specific compounds thereof are exemplified below.

  Thirdly, halides that generate hydrogen halide can also be used, and specific compounds thereof are exemplified below.

  Fourthly, an iron allene complex can be mentioned.

  Various organic solvents can be used in the ink of the present invention.

  Examples of solid oily media include beeswax, carnauba wax, rice wax, wood wax, jojoba oil, whale wax, candelilla wax, lanolin, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, petrolactam. Natural waxes such as polyethylene wax, chlorinated hydrocarbons, palmitic acid, stearic acid, behenic acid, tiglic acid, 2-acetonaphthobehenic acid, 12-hydroxystearic acid, dihydroxystearic acid and other organic acids; dodecanol, tetradeca Nord, Hexadecanol, Eicosanol, Docosanol, Tetracosanol, Hexacosanol, Octacosanol, Dodecenol, Myricyl Alcohol, Tetracenol, Hexadecenol, Eicosenol, Docoseno , Pinene glycol, hinokiol, butynediol, nonanediol, isophthalyl alcohol, mesicerine, hexanediol, decanediol, tetradecandiol, hexadecandiol, docosandiol, tetracosandiol, tvneol, phenylglycerin, eicosandiol , Octanediol, phenylpropylene glycol and other alcohols; bisphenol A, p-α-cumylphenol and other phenols; organic acid esters of the above organic acids such as glycerin, ethylene glycol and diethylene glycol; stearic acid cholesterol, palmitic acid cholesterol , Cholesterol, myristic acid cholesterol, behenic acid cholesterol, lauric acid cholesterol, melicinate cholesterol, etc. Fatty acid esters; saccharide fatty acid esters such as sucrose stearate, sucrose palmitate, saccharose behenate, saccharose laurate, saccharose melicinate, lactose stearate, lactose palmitate, lactose behenate, lactose laurate, lactose lactate; benzoyl Ketones such as acetone, diacetobenzene, benzophenone, tricosanone, heptacosanone, heptatriacontanone, hentriacontanone, stearone, laurone; oleic acid amide, lauric acid amide, stearic acid amide, ricinoleic acid amide, palmitic acid amide, Tetrahydrofuranamide, erucic acid amide, myristic acid amide, 12-hydroxystearic acid amide, N-stearyl erucic acid amide N-oleylstearic acid amide, N, N-ethylenebislauric acid amide, N, N-ethylenebisstearic acid amide, N, N-ethylenebisbehenic acid amide, N, N-xylylene bisstearic acid amide, N, N-butylenebisstearic acid amide, N, N-dioleyl adipic acid amide, N, N-dioleyl sebacic acid amide, N, N-distearyl sebacic acid amide, N, N-distearyl terephthalic acid amide, phenacetin, Amides such as toluamide and acetamide; Sulfonamides such as p-toluenesulfonamide, ethylbenzenesulfonamide and butylbenzenesulfonamide; Alkylnaphthalenes such as α-methylnaphthalene, β-methylnaphthalene and 2,6-dimethylnaphthalene; Dibutyl naphthalate, geo Chirufutareto, dibutyl adipate, dimethyl terephthalate, benzyl benzoate, carboxylic acid esters such as naphthalene-2,6-dicarboxylic acid methyl ester; tributyl phosphate, phosphoric acid esters such as triphenyl phosphate; and the like.

  Examples of the liquid oily medium include a mixed solvent of one kind or two or more kinds of organic solvents. Organic solvents include alcohols such as ethanol, pentanol, heptanol, octanol, cyclohexanol, benzyl alcohol, phenylethyl alcohol, phenylpropyl alcohol, furfuryl alcohol, anise alcohol; ethylene glycol monoethyl ether, ethylene glycol monophenyl ether , Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol diacetate, ethylene glycol mono Ethyl ether acetate , Glycol derivatives such as propylene glycol diacetate; ketones such as benzyl methyl ketone, diacetone alcohol, cyclohexanone; ethers such as butyl phenyl ether, benzyl ethyl ether, hexyl ether; ethyl acetate, amyl acetate, benzyl acetate, phenyl acetate Ethyl, phenoxyethyl acetate, ethyl phenylacetate, benzyl propionate, ethyl benzoate, butyl benzoate, ethyl laurate, butyl laurate, isopropyl myristate, isopropyl palmitate, triethyl phosphate, tributyl phosphate, tricresyl phosphate, Diethyl phthalate, Dibutyl phthalate, Diethyl malonate, Dipropyl malonate, Diethyl diethyl malonate, Diethyl succinate, Dibutyl succinate, Diethyl glutarate , Diethyl adipate, dibutyl adipate, di (2-methoxyethyl) adipate, diethyl sebacate, diethyl maleate, dibutyl maleate, dioctyl maleate, diethyl fumarate, dioctyl fumarate, 3-hexenyl cinnamate, etc. Esters of hydrocarbons; hydrocarbon solvents such as petroleum ether, petroleum benzyl, tetralin, delican, 1-amylbenzene, dimethylnaphthalene; acetonitrile, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane And polar solvents such as propylene carbonate, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, and N, N-diethyldodecanamide. These solvents may be used alone or in combination of two or more.

  In the ink of the present invention, in addition to the above description, if necessary, the output stability, print head and ink cartridge compatibility, storage stability, image storage stability, and other various performance improvement objectives are known. Various additives such as a viscosity modifier, a specific resistance modifier, a film forming agent, an ultraviolet absorber, an antioxidant, a discoloration inhibitor, an antifungal agent, and a rust inhibitor can be appropriately selected and used.

  The recording medium that can be used for image formation with the ink of the present invention is not particularly limited, and is made of a paper base such as plain paper or art paper used for copying, ordinary uncoated paper, base paper, etc. In addition to coated paper with both surfaces coated with resin, various non-absorbable plastics and films used for so-called soft packaging can be used. Examples of various plastic films include PET film, OPS film, and OPP. A film, an ONy film, a PVC film, a PE film, and a TAC film can be mentioned. Moreover, it is applicable also to metals and glass.

  Next, the ink jet recording method of the present invention will be described.

  A first aspect of the ink jet recording method of the present invention is an ink jet recording method for forming an image by heating an ink jet ink containing an oil gelling agent, wherein the ink jet ink landed on a recording medium is cooled. It is characterized by using a solidifying means that gels. As the fixing means by gelation, for example, an ink jet recording apparatus used for ink jet recording is heated to a predetermined temperature in a relatively low temperature environment such as room temperature, and is then landed on a recording medium to obtain an environmental temperature. The ink is cooled below the phase transition temperature of the ink, such as a method of natural cooling and fixing, or a method of cooling the recording medium in advance, or forcing cold air to the landing part to gel and fix it. The means that can be used can be appropriately selected and used.

  A second aspect of the ink jet recording method of the present invention is an ink jet recording method for forming an image by heating an ink for ink containing an oil gelling agent and an actinic ray curable composition, and landing on a recording medium. The inkjet ink has two or more fixing means, and at least one of the fixing means is the gelling fixing means described above, and further two or more fixing means It is preferable that the converting means is a fixing means by gelation and an fixing means for curing the ink by irradiation with actinic rays.

  Hereinafter, the fixing means by ink curing by actinic ray irradiation according to the present invention will be described.

  In the ink jet recording method of the present invention, the ink containing the oil gelling agent of the present invention and the actinic ray curable composition is drawn on a recording medium and then drawn, and then ink droplets are gelled by the oil gelling agent. A method of curing the ink by irradiation with actinic rays such as ultraviolet rays is preferred.

(Total ink film thickness after ink landing)
In the present invention, the total ink film thickness after the ink has landed on the recording medium and cured by irradiation with actinic rays is preferably 2 to 25 μm. Here, “total ink film thickness” means the maximum value of the film thickness of the ink drawn on the recording medium, and even for a single color, other two colors are superimposed (secondary color), three colors are superimposed, four colors are used. Even when recording is performed by the overlapping (white ink base) inkjet recording method, the meaning of the total ink film thickness is the same.

(Ink ejection conditions)
As the ink ejection conditions, it is preferable from the viewpoint of ejection stability that the recording head and ink are heated to 35 to 100 ° C. and ejected. The ink of the present invention has a large viscosity fluctuation range due to temperature fluctuation, and the viscosity fluctuation directly affects the droplet size and droplet ejection speed, causing image quality degradation. It is preferable to keep in and emit in that state. The predetermined temperature range is preferably set temperature ± 5 ° C., more preferably set temperature ± 2 ° C., and further preferably set temperature ± 1 ° C. The set temperature here refers to a reference temperature set as the temperature of ink when ink is ejected.

  In the present invention, the amount of liquid droplets ejected from each nozzle of the recording head is preferably 2 to 15 pl. Originally, in order to form a high-definition image, it is necessary for the amount of droplets to be within this range, but when discharging with this amount of droplets, the above-described discharge stability becomes particularly severe. According to the present invention, even when ejection is performed with a small droplet amount such as 2 to 15 pl, the ejection stability is improved and a high-definition image can be stably formed.

(Light irradiation conditions after ink landing)
In the image forming method of the present invention, it is preferable that the active light is applied within 10 seconds after the ink landing as the irradiation condition of the active light, more preferably 0.001 to 5 seconds, and still more preferably 0. .001 seconds to 2 seconds. In order to form a high-definition image, it is an important requirement that the irradiation timing be as early as possible.

  A basic method of actinic ray irradiation is disclosed in JP-A-60-132767. According to this, the light source is provided on both sides of the head unit, and the head and the light source are scanned by the shuttle method. Irradiation is performed after a certain period of time after ink landing. Further, the curing is completed by another light source that is not driven. In US Pat. No. 6,145,979, as an irradiation method, a method using an optical fiber or a method of applying a collimated light source to a mirror surface provided on the side of the head unit and irradiating the recording unit with UV light is disclosed. Yes. Any of these irradiation methods can be used in the image forming method of the present invention.

  In addition, the irradiation of actinic rays is divided into two stages. First, actinic rays are irradiated by the above-described method within 0.001 to 2.0 seconds after ink landing, and actinic rays are further irradiated after all printing is completed. The method is also a preferred embodiment. By dividing the irradiation of actinic rays into two stages, it is possible to further suppress the shrinkage of the recording medium that occurs during ink curing.

  Conventionally, in the UV ink jet system, a light source with high illuminance in which the total power consumption of the light source exceeds 1 kW · hr is usually used in order to suppress dot spreading and bleeding after ink landing. However, when these light sources are used, particularly in printing on a shrink label or the like, the shrinkage of the recording medium is so large that it cannot be used practically.

  In the present invention, it is preferable to use an actinic ray having a maximum illuminance in a wavelength region of 254 nm, and a high-definition image can be formed even when a light source having a total power consumption of 1 kW · hr or more is used, and the recording medium is contracted. Is also within a practically acceptable level.

In the present invention, it is preferable that the total power consumption of the light source for irradiating actinic rays is less than 1 kW · hr. Examples of the light source having a total power consumption of less than 1 kW · hr include, but are not limited to, a fluorescent tube, a cold cathode tube, a hot cathode tube, and an LED. Moreover, it is preferable that it is 0.1-50 mW / cm < ² > as an irradiation dose.

  Next, an example of an ink jet recording apparatus (hereinafter simply referred to as a recording apparatus) that can be used in the ink jet recording method of the present invention will be described.

  Hereinafter, a recording apparatus that can be used in the present invention will be described with reference to the drawings as appropriate. Note that the recording apparatus shown in the drawings is merely an embodiment of the recording apparatus that can be preferably used in the present invention, and the present invention is not limited to this drawing.

  FIG. 1 is a front view showing a configuration of a main part of an ink jet recording apparatus that can be used in the present invention. The recording apparatus 1 includes a head carriage 2, a recording head 3, irradiation means 4 as means for irradiating actinic rays, a platen unit 5, and the like. In the recording apparatus 1, the platen unit 5 is installed under the recording medium P. The platen unit 5 has a function of absorbing ultraviolet rays, and absorbs excess ultraviolet rays that have passed through the recording medium P. As a result, a high-definition image can be reproduced very stably.

  The recording medium P is guided by the guide member 6 and moves from the near side to the far side in FIG. 1 by the operation of the conveying means (not shown). A head scanning unit (not shown) scans the recording head 3 held by the head carriage 2 by reciprocating the head carriage 2 in the Y direction in FIG.

  The head carriage 2 is installed on the upper side of the recording medium P and accommodates a plurality of recording heads 3 to be described later according to the number of colors used for image printing on the recording medium P and an ejection port (nozzle) arranged on the lower side. To do. The head carriage 2 is installed with respect to the main body of the recording apparatus 1 in such a manner that it can reciprocate in the Y direction in FIG. 1, and reciprocates in the Y direction in FIG. 1 by driving the head scanning means.

  In FIG. 1, the head carriage 2 is white (W), yellow (Y), magenta (M), cyan (C), black (K), light yellow (Ly), light magenta (Lm), and light cyan (Lc). In the drawing, the recording head 3 for light black (Lk) and white (W) is drawn. However, the number of the recording heads 3 accommodated in the head carriage 2 and the number of the recording heads 3 are accommodated in the embodiment. The color of the ink to be determined is appropriately determined.

  The recording head 3 records the ink containing the actinic radiation curable composition supplied from the ink supply means (not shown) from the discharge port by the operation of a plurality of discharge means (not shown) provided therein. The ink is discharged toward the medium P. The ink ejected by the recording head 3 is composed of a coloring material, a polymerizable monomer, an initiator and the like in addition to the oil gelling agent. After landing on the recording medium P, the ink is cooled and gelled. In the example, when irradiated with ultraviolet rays as an irradiation means, the photopolymerization initiator has a property of being cured by a monomer crosslinking or polymerization reaction accompanying the action of a photopolymerization initiator as a catalyst.

  The recording head 3 moves from one end in the width direction of the recording medium P to the other end of the recording medium P in the Y direction in FIG. The ink of the present invention is ejected as ink droplets on the possible region), and the ink droplets are landed on the landable region.

  The above-described scanning is performed as many times as necessary, and after the ink of the present invention is ejected toward one landing possible region, the recording medium P is appropriately moved from the front to the back in FIG. The ink of the present invention is ejected to the next landable area adjacent to the rearward direction in FIG.

  By repeating the above-described operation and ejecting the ink of the present invention from the recording head 3 in conjunction with the head scanning means and the conveying means, an image composed of the aggregate of the ink of the present invention is formed on the recording medium P.

  The irradiation unit 4 includes an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength. Here, as the ultraviolet lamp, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (light emitting diode), and the like can be applied. A cathode tube, a hot cathode tube, a mercury lamp or black light is preferred. In particular, a low-pressure mercury lamp, a hot cathode tube, a cold cathode tube, and a germicidal lamp that emit ultraviolet light having a wavelength of 254 nm are preferable because they can prevent bleeding and control the dot diameter efficiently. By using black light as the active light source of the irradiation means 4, the irradiation means 4 for curing the UV ink can be produced at low cost.

  The irradiating means 4 has the same shape as the largest one that can be set by the recording apparatus 1 among the landable areas where the recording head 3 ejects UV ink by one scan driven by the head scanning means, or from the landable area. Also has a large shape.

  The irradiation means 4 is fixed on both sides of the head carriage 2 so as to be substantially parallel to the recording medium P.

  As described above, as a means for adjusting the illuminance of the ink discharge portion, not only the entire recording head 3 is shielded, but in addition, the ink discharge of the recording head 3 is determined from the distance h1 between the irradiation means 4 and the recording medium P. It is effective to increase the distance h2 between the portion 31 and the recording medium P (h1 <h2), to separate the recording head 3 from the irradiation means 4, or to increase the distance between them. Further, it is more preferable to provide a bellows structure 7 between the recording head 3 and the irradiation means 4.

  Here, the wavelength of the ultraviolet rays irradiated by the irradiation means 4 can be changed as appropriate by replacing the ultraviolet lamp or filter provided in the irradiation means 4.

  The ink of the present invention has excellent ejection stability and is particularly effective when an image is formed using a line head type recording apparatus.

  FIG. 2 is a top view illustrating an example of a configuration of a main part of a line head type ink jet recording apparatus that can be used in the present invention. Those having the same functions as those shown in FIG. 1 will be described using the same reference numerals as those in FIG.

  The ink jet recording apparatus shown in FIG. 2 is called a line head system, and a plurality of ink jet recording heads 3 of each color are fixedly arranged on the head carriage 2 so as to cover the entire width of the recording medium P. Has been.

  On the other hand, on the downstream side of the head carriage 2, there is provided irradiation means 4 arranged so as to cover the entire width of the recording medium P and cover the entire width direction of the ink printing surface. As the ultraviolet lamp used in the illuminating means 4, the same one as described in FIG. 1 can be used.

  In the line head system shown in FIG. 2, the head carriage 2 and the irradiating means 4 are fixed, and only the recording medium P is transported, and ink is ejected and cured to form an image.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<Preparation of ink>
[Preparation of Ink 1]
The following additives were sequentially mixed, heated to 80 ° C. and stirred, and the resulting liquid was filtered with a # 3000 metal mesh filter under heating and cooled to prepare ink 1. The total solid component amount of Ink 1 at 20 ° C. is 29%.

Isopar L (Exxon) 51 parts Octadecenol 10 parts Soybean oil 10 parts Oil Black HBB (CI Solvent Black 3 Orient) 4 parts Oil gelling agent: Exemplified compound OG-2 25 parts [Preparation of ink 2]
The following additives were sequentially mixed, heated to 80 ° C. and stirred, and then the obtained liquid was filtered with a filter under heating and cooled to prepare ink 2. The total amount of solid components at 20 ° C. of ink 2 is 9%.

IsoparL (Exxon) 71 parts Octadecenol 10 parts Soybean oil 10 parts Oil Black HBB (CI Solvent Black3 manufactured by Orient) 4 parts Oil gelling agent: Exemplified compound OG-3 5 parts [Preparation of ink 3]
The following additives were sequentially mixed, heated to 80 ° C. and stirred, and then the obtained liquid was filtered through a # 3000 metal mesh filter under heating, and cooled to prepare ink 3. The total amount of solid components at 20 ° C. of ink 3 is 30%.

IsoparL (Exxon) 45 parts Octadecenol 5 parts Soybean oil 5 parts Pigment dispersion 1 (below) 20 parts Oil gelling agent: Exemplified compound OG-2 25 parts <Preparation of pigment dispersion 1>
Pigment: Carbon black (MA7, manufactured by Mitsubishi Kasei Co., Ltd.) 20 parts Pigment dispersant: Solsperse 17000 (manufactured by Avecia) 5 parts Solvent: IsoparL (manufactured by Exxon) 75 parts After mixing the above additives, the mixture is kneaded using a bead mill. Thus, a pigment dispersion 1 was prepared.

  As a result of measuring the volume average particle diameter of the pigment particles of this black pigment dispersion 1 using a Zetasizer 1000 (manufactured by Malvern), it was 105 nm.

[Preparation of Inks 4 to 8]
Inks 1 to 8 were prepared in the same manner as in preparations 1 to 3 except that the types and addition amounts of the additives were changed as shown in Table 1.

  The details of each abbreviation described in Table 1 are as follows.

* 1: Octadecenol * 2: Oil Black HBB (CI Solvent Black 3 manufactured by Orient)
* 3: trans-4-t-butyl-1-phenyl-cyclohexanol << Measurement of each characteristic value of ink >>
(Measurement of volume average particle diameter of pigment particles)
After the inks 3, 4, 6, and 8 were diluted 1000 times with each ink solvent, the volume average particle diameter was measured using the Zetasizer 1000 (supra).

(Measurement of phase transition temperature)
Place each gel-like ink test piece on a melting point measuring machine (ATM-01 ATM-01), heat at a heating rate of 5 ° C / min or less, measure the temperature at which the test piece melts, and repeat this operation three times. The average value was calculated repeatedly, and the first decimal place was rounded off to obtain the ink phase transition temperature.

[Measurement of penetration (20 ° C)]
Using a needle penetration testing apparatus shown in FIG. 1 of JIS K 2207-1996, a load of 10 g ± 0.1 g is applied to the needle having the shape shown in FIG. It was. On the other hand, in a state where each ink as a specimen is put in a glass container and kept at 20 ± 0.1 ° C., the needle is vertically penetrated into the ink surface together with the holding device and the weight, and the tip of the needle and the ink surface are The penetration distance (mm) at 5 seconds after contact was measured with a dial gauge, and a value 10 times the obtained value was obtained as the penetration (20 ° C.).

  Table 1 shows the measurement results obtained as described above.

<< Inkjet image formation >>
Using a piezo-type recording head equipped with a heater with a nozzle diameter of 25 μm and 256 nozzles (128 nozzles x 2 rows, staggered arrangement, 1 row nozzle pitch 360 dpi), ink tank, supply pipe, front of head The chamber ink tank, the pipe with filter, and the recording head were thermally insulated, and the measured phase transition temperature + 20 ° C. was heated. The line head type ink jet recording apparatus having the configuration shown in FIG. 2 including the above configuration is loaded with each of the inks prepared as described above, and printed on plain paper (XEROX 4024, manufactured by XEROX). Images were printed to obtain images 1-8.

  The piezo head emits at a droplet speed of about 8 m / sec under the conditions of 23 ° C. and 55% RH under the condition that the amount of each droplet is 4 pl. The ink droplets were gelled and fixed at room temperature. For character printing, a recording head was mounted on an XY drive stage, and printing was performed at a recording resolution of 1440 dpi × 1440 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

<Evaluation of formed image>
[Evaluation of character quality]
The degree of bleeding of the created 3P black characters was observed using a loupe, and the character quality was evaluated according to the following criteria.

◎: There is no feathering in the character outline, and it is clearly observed. ○: Slight feathering is observed in the character outline, but the character quality is good. △: Feathering occurs in the printed character. , Contour disturbance is slightly large ×: Disturbance at the outline is severe and character discrimination is difficult. ××: Clear character crushing occurs and character discrimination is impossible.
The density of the back surface of the black solid image part created above was measured using an optical densitometer (938 spectral densitometer manufactured by X-Rite), and the resistance to back-through was evaluated according to the following criteria.

A: The back surface density is less than 0.05. O: The back surface density is 0.05 or more and less than 0.08. Δ: The back surface density is 0.08 or more and less than 0.12. 12 or more and less than 0.15 XX: Back surface concentration is 0.15 or more [Evaluation of resistance to high temperature bleeding]
The 3P black characters created above were allowed to stand for 10 days in an environment of 40 ° C. and 55% RH, and then the degree of bleeding of the black characters was observed using a loupe, and high-temperature bleeding resistance was evaluated according to the following criteria.

◎: There is no feathering in the character outline, and it is clearly observed. ○: Slight feathering is observed in the character outline, but the character quality is good. △: Feathering occurs in the printed character. , Contour disturbance is slightly large ×: Disturbance at the outline is severe and character discrimination is difficult to make ××: Clear character crushing occurs and character discrimination is not possible [Evaluation of Ink Transfer Resistance]
The above-prepared image is overlaid with plain paper (XEROX 4024 manufactured by XEROX) on the image at a high temperature of 55 ° C. and left for 6 hours with a 4 kg weight on it, and then the ink is transferred to the overlaid plain paper. The ink transfer resistance was evaluated according to the following criteria.

○: Ink transfer to plain paper was not recognized at all △: Ink transfer to plain paper was recognized slightly ×: Clear ink transfer to plain paper was confirmed XX: Quite intense to plain paper Ink transfer was observed [Evaluation of emission stability]
The printer loaded with each of the inks prepared above was changed in a temperature range of 10 to 40 ° C. in 12 hours, and after repeating this 10 cycles, the image was emitted and visually observed for the absence of nozzles, The emission stability was evaluated according to the following criteria.

○: No nozzle missing was observed. Δ: Outgoing failure was observed in 1 to 5 nozzles among all nozzles 256. X: Outgoing failure was observed in 6 to 19 nozzles among all nozzles 256. Xx: Out of all nozzles 256, 20 or more nozzles were found to have poor emission. Table 2 shows the results obtained as described above.

  As is apparent from the results in Table 2, the oil gelling agent is contained, the phase transition temperature is 30 ° C. or higher and lower than 100 ° C., and the penetration (20 ° C.) is 1 or higher and 100 or lower. It can be seen that the ink is superior in character quality of the formed image, resistance to back-through, high-temperature bleeding resistance and ink transfer resistance, as well as excellent emission stability, as compared with the comparative example.

Example 2
<Preparation of ink>
[Preparation of ink 9]
The following additives were mixed in order, heated to 80 ° C. and stirred, and then the obtained liquid was filtered through a # 3000 metal mesh filter under heating and cooled to prepare ink 9. The total amount of solid components of ink 9 at 20 ° C. is 9.8%.

Isopar L (manufactured by Exxon) 65 parts Octadecenol 5 parts Soybean oil 5 parts Pigment dispersion 2 (below) 20 parts Oil gelling agent: Exemplified compound OG-3 5 parts <Preparation of pigment dispersion 2>
Pigment: Magenta pigment (Hostperm Pink E, manufactured by Clariant) 18 parts Pigment dispersant: Solsperse 17000 (produced by Avecia) 6 parts Solvent: Isopar L (produced by Exxon) 76 parts After mixing each of the above additives, the meat milled using a bead mill Thus, a pigment dispersion 2 was prepared.

  It was 80 nm as a result of measuring the volume average particle diameter of the pigment particle of this pigment dispersion 2 using Zetasizer 1000 (made by Malvern).

[Preparation of inks 10 to 16]
Inks 10 to 16 were prepared in the same manner as in the preparation of the ink 9, except that the type and amount of each additive were changed as shown in Table 3. Ink preparation using Exemplified Compound OG-2 as an oil gelling agent was heated to 80 ° C., and ink not using an oil gelling agent was prepared at 40 ° C.

<Measurement of each characteristic value of ink>
For the inks 9 to 16 prepared as described above, in the same manner as in the method described in Example 1, measurement of the volume average particle diameter of the pigment particles, measurement of the phase transition temperature, measurement of the penetration degree (20 ° C.), total solid components The amount was measured and the results obtained are shown in Table 3.

<< Formation and evaluation of inkjet image >>
In the same manner as in the method described in Example 1, the images 11 to 18 were formed using the inks 9 to 16 prepared above, and then the character quality was evaluated according to the method described in Example 1. Evaluation of evaluation, evaluation of resistance to high temperature bleeding, evaluation of ink transfer resistance, evaluation of emission stability, and evaluation of dispersion stability were performed according to the following methods.

[Evaluation of dispersion stability]
Each ink prepared above was put in a glass container and sealed, and then stored alternately in an environment of 10 ° C. and an environment of an ink phase transition temperature + 20 ° C. for 12 hours, respectively, and then the volume of pigment particles in the ink. The average particle size was measured using a Zetasizer 1000 (supra), the state of the ink liquid was further visually observed, and the dispersion stability was evaluated according to the following criteria.

○: The volume average particle size difference (* A) of the pigment particles before and after the storage treatment is less than 5%. Δ: The volume average particle size difference of the pigment particles before and after the storage treatment is 5% or more and less than 10%. ×: The volume average particle size difference between the pigment particles before and after the storage treatment is 10% or more. XX: The ink is separated in the gel state even at the temperature of the ink phase transition temperature + 20 ° C. * A : Volume average particle diameter difference of pigment particles = {(Volume average particle diameter after storage process) − (Volume average particle diameter before storage process)} / (Volume average particle diameter before storage process) × 100 (%)
Table 4 shows the results obtained as described above.

  As is clear from the results of Table 4, similar to the results of Example 1, an oil gelling agent was contained, the phase transition temperature was 30 ° C. or higher and less than 100 ° C., and the penetration (20 ° C.) was 1 or higher. The ink of the present invention, which is 100 or less, is superior to the comparative example in the character quality of the formed image, resistance to back-through, high temperature bleeding resistance, ink transfer resistance, and emission stability, and in addition, the dispersion stability of the ink. It turns out that it is favorable.

Example 3
<Preparation of ink>
[Preparation of Ink 17]
The following additives were mixed in sequence, heated to 80 ° C. and stirred, and the resulting liquid was filtered with a # 3000 metal mesh filter under heating, cooled and cooled to an oil gelling agent and an actinic ray curable composition. Ink 17, which is a cyan ink containing a product, was prepared. The total solid component amount of the ink 17 at 20 ° C. is 7.4%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 60 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 25 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 5 parts Pigment dispersion 3 (below) 10 parts Oil gelling agent: Exemplified compound OG-3 5 parts <Preparation of pigment dispersion 3>
Pigment: Cyan pigment (made by Hostperm Blue BFL Clariant)
20 parts Pigment dispersant: Solsperse 36000 (manufactured by Avecia) 4 parts Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 76 parts The above additives were mixed and then kneaded using a bead mill to prepare pigment dispersion 3.

  It was 90 nm as a result of measuring the volume average particle diameter of the pigment particles of this pigment dispersion 3 using Zetasizer 1000 (manufactured by Malvern).

[Preparation of inks 18 to 21]
Inks 18 to 21 were prepared in the same manner as in the preparation of the ink 18 except that the type and amount of each additive were changed as shown in Table 5. Ink preparation using Exemplified Compound OG-2 as an oil gelling agent was heated to 80 ° C., and ink not using an oil gelling agent was prepared at 40 ° C.

  The details of each abbreviation described in Table 5 are as follows.

OXT221: Oxetane compound (OXT221 manufactured by Toagosei Co., Ltd.)
E4030: Epoxy soybean oil (E4030 manufactured by Shin Nippon Chemical Co., Ltd.)
SP152: Adekaoptomer SP152 (Asahi Denka)
<Measurement of each characteristic value of ink>
For the inks 17 to 21 prepared as described above, in the same manner as in the method described in Example 1, measurement of the volume average particle diameter of the pigment particles, measurement of the phase transition temperature, measurement of the penetration degree (20 ° C.), total solid components The amount was measured and the results obtained are shown in Table 5.

<< Inkjet image formation >>
A line head type ink jet recording apparatus having the configuration shown in FIG. 2 having a piezo type ink jet nozzle is loaded with each of the inks prepared above, and plain paper (XEROX 4024 made by XEROX) and art paper (made by Mitsubishi Paper Industries) A 3P Mincho-style character image and a cyan solid image were printed on both sides of the diamond art N) to obtain images 31 to 35. The ink supply system was composed of an ink tank, a supply pipe, a front chamber ink tank immediately before the head, a pipe with a filter, and a piezo head. The ink was insulated from the front chamber tank to the head portion and heated to the ink phase transition temperature + 20 ° C. The piezo head has a nozzle diameter of 25 μm, 256 nozzles (128 nozzles × 2 rows, staggered arrangement, 1 row nozzle pitch 360 dpi), and a droplet velocity of about 8 m under the condition that the amount of each droplet is 4 pl. The ink was ejected at / sec, and after the ink liquid landed on each recording medium, the ink droplets were gelled and fixed at room temperature. For character printing, a recording head was mounted on an XY drive stage, and printing was performed at a recording resolution of 1440 dpi × 1440 dpi. After each ink has landed, 0.5 seconds after the ink has landed by a lamp unit disposed on the upper part of the carriage, a high-pressure mercury lamp VZero085 (manufactured by INTEGRATION TECHNOLOGY) has an energy density of 140 W / cm and an illuminance of 20 mJ / cm ^2. The ink was cured by irradiating with ultraviolet rays at (integrated light amount). In addition, the illumination intensity of the irradiation light source was measured and displayed by measuring an integrated illumination intensity of 254 nm using UVPF-A1 manufactured by Iwasaki Electric Co., Ltd. The above image formation was performed in an environment of 23 ° C. and 55% RH.

<Evaluation of formed image>
About the created images 31 to 35, according to the methods described in Examples 1 and 2, character quality, back-through resistance, emission stability and dispersion stability were evaluated, and UV curability was evaluated according to the following method. .

[Evaluation of UV curability]
After pasting the cello tape (registered trademark) on the solid image formed on the above art paper, the image state when peeled off in the vertical method was visually observed. The case where peeling was observed was evaluated as Δ, and the case where image peeling was clearly observed was evaluated as X.

  Table 6 shows the results obtained as described above.

  As is apparent from the results in Table 6, an oil gelling agent and an actinic ray curable composition are contained, the phase transition temperature is 30 ° C. or more and less than 100 ° C., and the penetration (20 ° C.) is 1 or more, 100 The following ink of the present invention is superior in character quality of the formed image as compared with the comparative example, and also has excellent emission stability and dispersion stability as an ink, and is excellent in UV curability of the formed image. I understand that.

Example 4
<< Preparation of pigment dispersion >>
[Preparation of Yellow Pigment Dispersion 1]
Pigment: Yellow pigment (manufactured by Novoperm P-HG Clariant) 15 parts Pigment dispersant: Solsperse 36000 (manufactured by Avecia) 5 parts Oxetane compound (manufactured by OXT221 Toagosei Co., Ltd.) 80 parts After mixing the above additives, a bead mill is used. The yellow pigment dispersion 1 was prepared by kneading. As a result of measuring the volume average particle diameter of the pigment particles of this yellow pigment dispersion 1 using a Zetasizer 1000 (manufactured by Malvern), it was 120 nm.

[Preparation of magenta pigment dispersion 1]
Pigment: Magenta pigment (Hostperm Pink E, manufactured by Clariant) 15 parts Pigment dispersant: Solsperse 36000 (manufactured by Avecia) 5 parts Oxetane compound (manufactured by OXT221, Toagosei Co., Ltd.) 80 parts Meat was prepared to prepare a magenta pigment dispersion 1. As a result of measuring the volume average particle diameter of the pigment particles of this magenta pigment dispersion 1 using a Zetasizer 1000 (manufactured by Malvern), it was 100 nm.

[Preparation of Cyan Pigment Dispersion 1]
Pigment: Cyan pigment (made by Hostperm Blue B2G Clariant)
20 parts Pigment dispersant: Solsperse 36000 (manufactured by Avecia) 5 parts Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 75 parts The above additives were mixed and then kneaded using a bead mill to prepare cyan pigment dispersion 1 . It was 85 nm as a result of measuring the volume average particle diameter of the pigment particle of this cyan pigment dispersion liquid 1 using Zetasizer 1000 (made by Malvern).

[Preparation of Black Pigment Dispersion 1]
Pigment: Black pigment (carbon black MA100, manufactured by Mitsubishi Chemical Corporation) 20 parts Pigment dispersant: Solsperse 36000 (manufactured by Avecia) 5 parts Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 75 parts After mixing the above additives, a bead mill is used. The black pigment dispersion 1 was prepared by kneading. It was 80 nm as a result of measuring the volume average particle diameter of the pigment particle of this black pigment dispersion 1 using Zetasizer 1000 (made by Malvern).

<Preparation of ink set>
An ink set comprising the following color inks was prepared.

[Preparation of yellow ink]
The following additives were mixed in sequence, heated and stirred at 80 ° C., and the resulting liquid was filtered through a # 3000 metal mesh filter under heating and then cooled to obtain an oil gelling agent and an actinic ray curable type. A yellow ink containing the composition was prepared. The total solid component amount of yellow ink at 20 ° C. is 11%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 70 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 30 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 8 parts Yellow pigment dispersion 1 30 parts Oil gelling agent: 5 parts of exemplary compound OG-3 [Preparation of magenta ink]
The following additives were mixed in sequence, heated and stirred at 80 ° C., and the resulting liquid was filtered through a # 3000 metal mesh filter under heating and then cooled to obtain an oil gelling agent and an actinic ray curable type. A magenta ink containing the composition was prepared. The total solid component amount of the magenta ink at 20 ° C. is 9.0%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 65 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 25 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 7 parts Magenta pigment dispersion 1 20 parts Oil gelling agent: Exemplified compound OG-3 5 parts [Preparation of cyan ink]
The following additives were mixed in sequence, heated and stirred at 80 ° C., and the resulting liquid was filtered through a # 3000 metal mesh filter under heating and then cooled to obtain an oil gelling agent and an actinic ray curable type. A cyan ink containing the composition was prepared. The total solid component amount of cyan ink at 20 ° C. is 7.5%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 60 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 25 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 7 parts Cyan pigment dispersion 1 10 parts Oil gelling agent: 5 parts of exemplary compound OG-3 [Preparation of black ink]
The following additives were mixed in sequence, heated and stirred at 80 ° C., and the resulting liquid was filtered through a # 3000 metal mesh filter under heating and then cooled to obtain an oil gelling agent and an actinic ray curable type. A black ink containing the composition was prepared. The total solid component amount of the black ink at 20 ° C. is 10%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 65 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 25 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 8 parts Black pigment dispersion 1 20 parts Oil gelling agent: 5 parts of exemplary compound OG-3 [Preparation of light magenta ink]
The following additives were mixed in sequence, heated to 80 ° C. and stirred, and then the resulting liquid was filtered through a # 3000 metal mesh filter under heating and cooled to obtain an oil gelling agent and an actinic ray curable type. A light magenta ink containing the composition was prepared. The total amount of solid components at 20 ° C. of light magenta ink is 6.0%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 60 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 25 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 7 parts Magenta pigment dispersion 1 5 parts Oil gelling agent: Exemplified compound OG-3 5 parts [Preparation of light cyan ink]
The following additives were mixed in sequence, heated to 80 ° C. and stirred, and then the resulting liquid was filtered through a # 3000 metal mesh filter under heating and cooled to obtain an oil gelling agent and an actinic ray curable type. A light cyan ink containing the composition was prepared. The total solid component amount of light cyan ink at 20 ° C. is 5.5%.

Actinic ray curable composition: Oxetane compound (OXT221, manufactured by Toagosei Co., Ltd.) 60 parts Actinic ray curable composition: Epoxy soybean oil (E4030, Shin Nippon Chemical Co., Ltd.) 25 parts Photopolymerization initiator: Adekaoptomer SP152 (Asahi Denka) 7 parts Cyan pigment dispersion 1 2 parts Oil gelling agent: Exemplified compound OG-3 5 parts << Measurement of each characteristic value of ink >>
For each color ink prepared as described above, the volume average particle diameter, phase transition temperature, penetration degree (20 ° C.), and total solid component amount of the pigment particles were measured in the same manner as described in Example 1. Table 7 shows the results.

<< Formation and evaluation of inkjet image >>
In the same manner as described in Example 3, 3P was applied to plain paper (XEROX 4024 manufactured by XEROX) and art paper (special art double-sided N manufactured by Mitsubishi Paper Industries) using an ink set composed of each color ink prepared above. A character image of Mincho and a JIS / SCID N5 “bicycle” image were printed, and in the same manner as described in Example 1, evaluation of character quality, evaluation of back-through resistance, evaluation of high-temperature bleeding resistance, ink resistance As a result of evaluating transferability, excellent effects could be confirmed in all evaluation items. Moreover, as a result of visually observing the created JIS / SCID N5 “bicycle” image, it was confirmed that the image was excellent in sharpness and high optical density was obtained.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Head carriage 3 Inkjet recording head 31 Ink ejection port 4 Irradiation means 5 Platen part 6 Guide member 7 Bellows structure P Recording material

Claims (1)

  It contains at least an oil gelling agent, has a phase transition temperature of 30 ° C. or higher and lower than 100 ° C., and has a penetration of 1 or more and 100 or less measured according to the method defined in JIS K 2207-1996. An inkjet image forming method for forming an image by ejecting an inkjet ink (with a temperature of 20 ° C. and a load of 10 g as measurement conditions) onto a recording medium from an inkjet recording head, the inkjet ink being 35 An inkjet image forming method, wherein the image is formed by discharging onto the recording medium while heating to -100 ° C.

Images