Adhesive liquid, image forming system, and image forming method

Abstract

Provided is an adhesive liquid that has good transferability of a printing layer and good washing fastness of a printing medium after image transfer.　The adhesive liquid of the present disclosure is characterized by containing water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, the weight change rate X before and after drying satisfying formula (1) or formula (2), and the storage elastic modulus E' at 110°C of a film obtained by drying the adhesive liquid before applying the heat and the pressure being 5.4 × 106 Pa or less. A is a weight ratio of the water in the total amount of the adhesive liquid, and B is a weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.　X < A (1) A ≤ X < B (2)

Description

Adhesive liquid, image forming system, and image forming method

[0001] The present disclosure relates to an adhesive liquid, an imaging system, and an imaging method.

[0002] Patent Document 1 discloses an image forming method for forming an image on a transfer-receiving body (printing medium) using an intermediate transfer recording medium in which a printing layer and an adhesive layer are formed on a transfer medium.

[0003] JP 2009-066789 A

[0004] One possible approach is to form a printing layer, such as a color print or a white print, on a transfer medium using an inkjet printer, then apply a powder adhesive to the printing layer using a device separate from the inkjet printer, and heat and melt the applied powder to create an intermediate transfer recording medium. In this case, heat and pressure are applied while the intermediate transfer recording medium and the printing medium are superimposed, and the transfer medium is peeled off, transferring the printing layer formed on the transfer medium to the printing medium. Alternatively, the powder adhesive may be replaced with a liquid adhesive (adhesive liquid). In this case, the inkjet printer ejects ink and adhesive liquid onto the intermediate transfer recording medium, which is then dried to create an intermediate transfer recording medium with an adhesive layer formed on the printing layer.

[0005] If the adhesive layer formed after drying is hard, there is a possibility that the printing layer will not transfer properly to the printing medium when the transfer medium is peeled off from the printing medium. Furthermore, the printing layer transferred to the printing medium may not be able to withstand the bending and folding forces that occur during washing, which may cause the image formed on the printing medium to crack.

[0006] Therefore, an object of the present disclosure is to provide an adhesive liquid, an image forming system, and an image forming method that provide good transferability of the print layer and good washing fastness of the print medium after image transfer.

[0007] In order to achieve the above object, the adhesive liquid of the present disclosure is an adhesive liquid that is ejected from an ejection head onto ink on a transfer medium having an ink receiving layer, and that adheres an image formed by the ink to a printing medium by applying heat and pressure after drying, the adhesive liquid comprising water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, and is characterized in that a weight change rate X before and after the drying satisfies the following formula (1) or (2), and a storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before applying the heat and pressure is 5.4 x 106 Pa or less: X<A (1) A≦X<B (2) In formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

[0008] The image forming system of the present disclosure comprises: an ink storage unit; an ink ejection unit that ejects ink stored in the ink storage unit onto a transfer medium by an inkjet system; an adhesive liquid storage unit; an adhesive liquid ejection unit that ejects adhesive liquid stored in the adhesive liquid storage unit onto the ink on the transfer medium by an inkjet system; a drying unit that dries the transfer medium onto which the adhesive liquid has been ejected; and a contact heating unit that applies heat and pressure after the drying to adhere an image formed by the ink to a print medium, wherein the adhesive liquid contains water, resin particles, an organic solvent, a crosslinking agent, and a surfactant; a weight change rate X before and after the drying satisfies the following formula (1) or (2); and a storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before the application of the heat and the pressure is 5.4 x 10 Pa or less. X<A (1) A≦X<B (2) In the formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in the formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

[0009] The image forming method of the present disclosure includes an ink ejection step, an adhesive liquid ejection step, a drying step, and a contact heating step, wherein the ink ejection step includes ejecting ink onto a transfer medium by an inkjet method, the adhesive liquid ejection step includes ejecting adhesive liquid onto the ink on the transfer medium by an inkjet method, the drying step includes drying the transfer medium onto which the adhesive liquid has been ejected, and the contact heating step includes applying heat and pressure after the drying to adhere an image formed by the ink to a print medium, wherein the adhesive liquid includes water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, and wherein a weight change rate X before and after the drying satisfies the following formula (1) or (2), and wherein a storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before the application of the heat and the pressure is 5.4 x 106 Pa or less. X<A (1) A≦X<B (2) In the formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in the formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

[0010] The adhesive liquid, image forming system, and image forming method of the present disclosure provide good transferability of the print layer and good wash fastness of the print medium after image transfer.

[0011] Fig. 1 is a schematic perspective view showing the configuration of an example of an image forming system of the present disclosure. Fig. 2 is a plan view showing a perspective view of the internal structure of an image forming apparatus in the image forming system of the present disclosure. Fig. 3 is a block diagram showing a schematic configuration of the image forming system of the present disclosure. Fig. 4 is a block diagram showing an example of the configuration of a control unit of an image forming apparatus in the image forming system of the present disclosure. Fig. 5 is a flowchart showing an example of steps in an image forming method of the present disclosure.

[0012] An embodiment of the present disclosure will be described. However, the present disclosure is not limited to the following embodiment. In the following drawings, the same parts are denoted by the same reference numerals. Furthermore, the descriptions of the embodiments can be mutually incorporated unless otherwise specified. Furthermore, the configurations of the embodiments can be combined unless otherwise specified.

[0013] First, the water, resin particles, organic solvent, crosslinking agent, and surfactant in the present disclosure will be described.

[0014] Examples of the water include ion-exchanged water and pure water. The content of the water relative to the total amount of the adhesive liquid (water ratio) is appropriately determined depending on the desired properties, etc. The water ratio may be, for example, the remainder of the other components. The water content is, for example, 5 wt % to 50 wt %, 5 wt % to 45 wt %, or 8 wt % to 40 wt %.

[0015] The resin particles may be contained in, for example, a resin emulsion. The resin emulsion is, for example, composed of the resin particles and a dispersion medium (e.g., water, etc.), and the resin particles are not dissolved in the dispersion medium but are dispersed with a specific particle diameter. The resin particles may be, for example, commercially available products. Examples of the resin particles include resin particles whose main component is polyurethane, polyacrylic acid, or polyacrylic acid ester. The resin particles may be one type of resin particles or two or more types of resin particles.

[0016] Commercially available resin particles include, for example, "Takelac (registered trademark) WS6021" and "Takelac (registered trademark) W6110" manufactured by Mitsui Chemicals, Inc.; and "Movinyl (registered trademark) W6761" manufactured by Japan Coating Resins Co., Ltd.

[0017] In the adhesive liquid, the solid content of the resin particles (which can also be said to be equivalent to the amount of active ingredient) relative to the total amount of the adhesive liquid is, for example, 20% by weight to 90% by weight, 30% by weight to 80% by weight, or 50% by weight to 70% by weight. Note that, for example, when a resin emulsion containing the resin particles is used, the "equivalent to the amount of active ingredient" refers to the amount of the resin particles themselves excluding a dispersion medium such as water.

[0018] Examples of the organic solvent include a wetting agent that prevents the adhesive liquid from drying on the nozzle surface of the ejection head, and a penetrating agent that adjusts the drying speed on the printing medium.

[0019] The wetting agent is not particularly limited, and examples thereof include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ketoalcohols such as diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethers such as polyalkylene glycols; polyhydric alcohols such as alkylene glycols, glycerin, trimethylolpropane, and trimethylolethane; 2-pyrrolidone; N-methyl-2-pyrrolidone; and 1,3-dimethyl-2-imidazolidinone. Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol. Examples of the alkylene glycol include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, and hexylene glycol. One type of wetting agent may be used, or two or more types of wetting agents may be used.

[0020] The content of the wetting agent in the total amount of the adhesive liquid is, for example, 0% by weight to 50% by weight, 3% by weight to 50% by weight, or 3% by weight to 20% by weight.

[0021] Examples of the penetrating agent include alkylene diols, glycol ether compounds, etc. Examples of the alkylene diols include 1,2-hexanediol, 1,2-heptanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, and 3-methyl-1,5-pentanediol. Examples of the glycol ether-based compound include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, propylene glycol-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether, tripropylene glycol-n-butyl ether, etc. One type of penetrating agent may be used, or two or more types of penetrating agents may be used.

[0022] The content of the penetrant relative to the total amount of the adhesive liquid is, for example, 0% by weight to 20% by weight, 1% by weight to 20% by weight, or 1% by weight to 15% by weight.

[0023] Examples of the crosslinking agent include an oxazoline group-containing compound, a carbodiimide group-containing compound, an isocyanate group-containing compound, an aziridine group-containing compound, an epoxy group-containing compound, and an aqueous crosslinking agent obtained by imparting a hydrophilic segment to a polycarbodiimide resin.

[0024] The crosslinking agent may be, for example, a commercially available product, such as "EPOCROS (registered trademark) WS-700" manufactured by Nippon Shokubai Co., Ltd., which is an oxazoline group-containing water-soluble polymer; or "SU-268A" manufactured by Meisei Chemical Industry Co., Ltd., which is an aqueous crosslinking agent in which the isocyanate group is masked with a blocking agent.

[0025] As the surfactant, for example, commercially available products may be used, and specific examples of the surfactant include silicone-based surfactants and acetylene-based surfactants.

[0026] Examples of commercially available silicone surfactants include "Silface (registered trademark) SAG002," "Silface (registered trademark) SAG005," and "Silface (registered trademark) SAG503A," all manufactured by Nissin Chemical Industry Co., Ltd.

[0027] Examples of commercially available acetylene surfactants include "Olfine (registered trademark) E1004," "Olfine (registered trademark) E1008," and "Olfine (registered trademark) E1010" manufactured by Nissin Chemical Industry Co., Ltd.; "Surfynol (registered trademark) 440," "Surfynol (registered trademark) 465," and "Surfynol (registered trademark) 485" manufactured by Air Products and Chemicals, Inc.; and "Acetylenol (registered trademark) E40" and "Acetylenol (registered trademark) E100" manufactured by Kawaken Fine Chemicals Co., Ltd.

[0028] The surfactant may further include other surfactants in addition to or instead of the silicone surfactant and the acetylene surfactant. Examples of the other surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. As the surfactant, one type of surfactant may be used, or two or more types of wetting agents may be used.

[0029] The content of the surfactant in the total amount of the adhesive liquid is, for example, 0.1% by mass to 2% by mass, 0.3% by mass to 1.5% by mass, or 0.3% by mass to 0.5% by mass.

[0030] The adhesive liquid of the present disclosure may further contain conventionally known additives, such as a pH adjuster, a viscosity adjuster, a surface tension adjuster, and an anti-mold agent, if necessary.

[0031] Next, the adhesive liquid of the present disclosure will be specifically described.

[0032] The weight change rate X of the adhesive liquid before and after drying in the present disclosure satisfies the following formula (1) or the following formula (2): X<A (1) A≦X<B (2)

[0033] In the formulas (1) and (2), A represents the weight ratio of water to the total amount of the adhesive liquid. That is, when the adhesive liquid of the present disclosure contains only water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, A represents the weight ratio of water to the total weight of water, resin particles, an organic solvent, a crosslinking agent, and a surfactant. Therefore, when the adhesive liquid of the present disclosure further contains the additives, etc., A represents the weight ratio of water to the total weight of water, resin particles, an organic solvent, a crosslinking agent, a surfactant, and the additives, etc.

[0034] Satisfying formula (1) means that even after the drying step in the image forming method of the present disclosure described below, the water and the high-boiling-point solvent contained in the organic solvent remain in the coating formed by drying the adhesive liquid (i.e., the coating is in a semi-dried state). For example, if the print medium to which an image formed with ink is to be adhered is a fabric or the like, a semi-dried coating facilitates penetration between the fibers of the fabric. This improves the adhesion between the image and the print medium after the contact heating step described below. Therefore, when transferring the image to the print medium, even if the transfer medium described below is peeled off from the print medium, transfer defects are less likely to occur.

[0035] In the formula (2), B is the weight ratio of the water and the organic solvent to the total amount of the adhesive liquid. That is, when the adhesive liquid of the present disclosure contains only water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, B in the formula (2) means the weight ratio of the water and the organic solvent to the total weight of the water, resin particles, the organic solvent, the crosslinking agent, and the surfactant. Therefore, when the adhesive liquid of the present disclosure further contains the additives, etc., B in the formula (2) means the weight ratio of the water and the organic solvent to the total weight of the water, resin particles, the organic solvent, the crosslinking agent, the surfactant, and the additives, etc.

[0036] Satisfying formula (2) means that the high-boiling point solvent contained in the organic solvent remains in the coating (semi-dried) even after the drying process in the image forming method of the present disclosure, which will be described later. It also means that the water contained in the adhesive liquid is in a sufficiently dried state. When the printing medium is a fabric or the like, a semi-dried coating facilitates penetration between the fibers of the fabric. Therefore, the adhesion between the image and the printing medium is improved after the contact heating process, which will be described later. Furthermore, the coating is less likely to strike through the printing medium than when formula (1) is satisfied. That is, because the amount of penetration of the coating into the printing medium is small, the coating is less likely to penetrate to the side opposite the printed surface of the printing medium. Therefore, when the image is transferred to the printing medium, the coating does not strike through the printing medium, and transfer defects are less likely to occur even if the transfer medium is peeled off from the printing medium.

[0037] As described above, the adhesive liquid of the present disclosure has a storage modulus E' at 110°C of 5.4×10 Pa or less of the coating formed by drying the adhesive liquid before the application of heat and pressure. That is, the storage modulus E' at 110°C of the coating after the drying step and before the contact heating step is 5.4×10 Pa or less. The upper limit of the storage modulus E' at 110°C may be, for example, 5.0×10 Pa or less, 4.0×10 Pa or less, 3.5×10 Pa or less, or 3.0×10 Pa or less, and the lower limit may be, for example, 7.0×10 Pa or more, 8.0×10 Pa or more, 9.0×10 Pa or more, 1.0×10 Pa or more, or 1.5×10 Pa or more.

[0038] By satisfying the storage modulus E' at 110°C, for example, when the printing medium is a fabric, the coating can easily penetrate between the fibers of the fabric. Therefore, after the contact heating step described below, the adhesion between the image and the printing medium is improved. Furthermore, even when the fabric on which the image is formed is washed, the formed image is less likely to crack, thereby improving washing fastness.

[0039] In the adhesive liquid of the present disclosure, for example, the storage modulus E' at 25°C of the coating formed by drying the adhesive liquid before the application of heat and pressure is 8.1×10 Pa or less. That is, the storage modulus E' at 25°C of the coating after the drying step and before the contact heating step is 8.1×10 Pa or less. The upper limit of the storage modulus E' at 25°C may be, for example, 8.0×10 Pa or less, 7.0×10 Pa or less, or 6.5×10 Pa or less, and the lower limit may be, for example, 2.0×10 Pa or more, 2.5×10 Pa or more, 3.0×10 Pa or more, or 4.0×10 Pa or more.

[0040] By satisfying the storage modulus E' at 25°C, for example, even when the fabric on which an image is formed is washed, the formed image is less likely to crack, and therefore washing fastness is further improved.

[0041] The ink for forming the image includes, for example, a coloring material, which may include, for example, a pigment, a dye, or the like.

[0042] The pigment is not particularly limited, and examples thereof include carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium oxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of organic pigments include azo pigments such as azo lake, insoluble azo pigment, condensed azo pigment, and chelate azo pigment; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye lake pigments such as basic dye lake pigments and acid dye lake pigments; nitro pigments; nitroso pigments; and aniline black daylight fluorescent pigments. Furthermore, the ink is not limited to these pigments, and pigments dispersible in an aqueous phase may also be included. Specific examples of these pigments include, for example, C.I. C.I. Pigment White 1, 4, 5, 6, 7, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28; C.I. Pigment Black 1, 6, and 7; C.I. Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 74, 78, 150, 151, 154, 180, 185, and 194; C.I. Pigment Orange 31 and 43; C.I. Examples of suitable pigments include C.I. Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1, 112, 122, 123, 139, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 209, 221, 222, 224, and 238; C.I. Pigment Violet 19 and 196; C.I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22, and 60; C.I. Pigment Green 7 and 36; and solid solutions of these pigments.

[0043] The pigment may be dispersed in a solvent using a resin dispersant (also referred to as a resin-dispersed pigment). Examples of the resin dispersant include general polymer dispersants (also referred to as pigment-dispersing resins or resin dispersants). Furthermore, in the adhesive liquid of the present disclosure, the pigment may be encapsulated in a polymer. Examples of the resin dispersant include those containing at least one of methacrylic acid and acrylic acid as a monomer, and commercially available products may be used. Examples of the resin dispersant include hydrophobic monomers such as styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, and aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids; or block copolymers, graft copolymers, or random copolymers composed of two or more monomers selected from the group consisting of acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, and fumaric acid derivatives, or salts thereof. Examples of the commercially available products include "JONCRYL (registered trademark) 611," "JONCRYL (registered trademark) 60," "JONCRYL (registered trademark) 586," "JONCRYL (registered trademark) 687," "JONCRYL (registered trademark) 63," and "JONCRYL (registered trademark) HPD296" manufactured by Johnson Polymer Co., Ltd.; "Disperbyk 190" and "Disperbyk 191" manufactured by BYK-Chemie; and "Solsperse 20000" and "Solsperse 27000" manufactured by Zeneca Chemicals.

[0044] The pigment may be dispersed using the pigment dispersing resin by a dispersing device, which is not particularly limited as long as it is a general dispersing device, and examples of the dispersing device include a ball mill, a roll mill, and a sand mill (e.g., a high-speed type).

[0045] The pigment may be a self-dispersing pigment. The self-dispersing pigment is, for example, one in which at least one hydrophilic functional group, such as a carbonyl group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, or a phosphate group, or a salt thereof, is chemically bonded to the pigment particle, either directly or via another group, thereby enabling dispersion in water without the use of a dispersant. The self-dispersing pigment may be one that has been treated by methods described, for example, in JP-A-8-3498, JP-T-2000-513396, JP-T-2008-524400, JP-T-2009-515007, or JP-T-2011-515535. Both inorganic and organic pigments can be used as raw materials for the self-dispersing pigment. Examples of pigments suitable for the treatment include carbon blacks such as "MA8" and "MA100" manufactured by Mitsubishi Chemical Corporation. The self-dispersing pigment may also be a commercially available product. Examples of the commercially available products include "CAB-O-JET (registered trademark) 200," "CAB-O-JET (registered trademark) 250C," "CAB-O-JET (registered trademark) 260M," "CAB-O-JET (registered trademark) 270Y," "CAB-O-JET (registered trademark) 300," "CAB-O-JET (registered trademark) 400," "CAB-O-JET (registered trademark) 450C," "CAB-O-JET (registered trademark) 465M," and "CAB-O-JET (registered trademark) 470Y," all manufactured by Cabot Corporation; "BONJET (registered trademark) BLACK CW-2" and "BONJET (registered trademark) BLACK CW-3," all manufactured by Orient Chemical Industry Co., Ltd.; and "LIOJET (registered trademark) WD BLACK" all manufactured by Toyo Ink Mfg. Co., Ltd. 002C" and the like.

[0046] The pigment may be one type of pigment or two or more types of pigments.

[0047] The dye is not particularly limited, and examples thereof include direct dyes, acid dyes, basic dyes, reactive dyes, etc. Specific examples of the dye include C.I. Direct Black, C.I. Direct Blue, C.I. Direct Red, C.I. Direct Yellow, C.I. Direct Orange, C.I. Direct Violet, C.I. Direct Brown, C.I. Direct Green, C.I. Acid Black, C.I. Acid Blue, C.I. Acid Red, C.I. Acid Yellow, C.I. Acid Orange, C.I. Acid Violet, C.I. Basic Black, C.I. Basic Blue, C.I. Basic Red, C.I. Basic Violet, and C.I. Food Black. Examples of the C.I. Direct Black include C.I. Examples of the C.I. Direct Black include Direct Black 17, 19, 32, 51, 71, 108, 146, 154, and 168. Examples of the C.I. Direct Blue include Direct Blue 6, 22, 25, 71, 86, 90, 106, and 199. Examples of the C.I. Direct Red include Direct Red 1, 4, 17, 28, 83, and 227. Examples of the C.I. Direct Yellow include Direct Yellow 12, 24, 26, 86, 98, 132, 142, and 173. Examples of the C.I. Direct Orange include Direct Orange 34, 39, 44, 46, and 60. Examples of the C.I. Direct Violet ... Examples of the C.I. Direct Violet 47 and 48 include C.I. Direct Brown 109 and the like. Examples of the C.I. Direct Green include C.I. Direct Green 59 and the like. Examples of the C.I. Acid Black include C.I. Acid Black 2, 7, 24, 26, 31, 52, 63, 112, and 118 and the like. Examples of the C.I. Acid Blue include C.I. Acid Blue 9, 22, 40, 59, 90, 93, 102, 104, 117, 120, 167, 229, and 234 and the like.Examples of the C.I. Acid Red include C.I. Acid Red 1, 6, 32, 37, 51, 52, 80, 85, 87, 92, 94, 115, 180, 256, 289, 315, and 317. Examples of the C.I. Acid Yellow include C.I. Acid Yellow 11, 17, 23, 25, 29, 42, 61, and 71. Examples of the C.I. Acid Orange include C.I. Acid Orange 7 and 19. Examples of the C.I. Acid Violet include C.I. Acid Violet 49. Examples of the C.I. Basic Black include C.I. Basic Black 2. Examples of the C.I. Basic Blue include C.I. Examples of the C.I. Basic Red include C.I. Basic Red 1, 2, 9, 12, 13, 14, and 37. Examples of the C.I. Basic Violet include C.I. Basic Violet 7, 14, and 27. Examples of the C.I. Food Black include C.I. Food Black 1 and 2.

[0048] The dye may be one type of dye or two or more types of dyes.

[0049] The ink may further contain conventionally known additives as needed, such as the resin particles, the organic solvent, the water, the crosslinking agent, the surfactant, the pH adjuster, the viscosity adjuster, the surface tension adjuster, and the antifungal agent.

[0050] The adhesive liquid is, for example, different from the ink and is used for purposes other than those of the ink. As described above, the ink contains, for example, the coloring material and is used to color the image. The adhesive liquid is ejected onto the ink ejected onto the transfer medium and is used to adhere the print medium and the image.

[0051] Next, the image forming system of the present disclosure will be described. The image forming system of the present disclosure may be a system including an ink storage unit, an ink discharge unit, an adhesive liquid storage unit, an adhesive liquid discharge unit, a drying unit (drying device), and a contact heating unit (heat bonding device), which are separate and independent units, or may be an integrated system including the ink storage unit, the ink discharge unit, the adhesive liquid storage unit, the adhesive liquid discharge unit, the drying unit, and the contact heating unit within a single housing.

[0052] Fig. 1 shows the configuration of an example of an image forming system according to the present disclosure. Fig. 2 is a perspective plan view showing the internal structure of the image forming apparatus 1 shown in Fig. 1. In Fig. 1 and Fig. 2, which will be described later, the front, rear, left, and right directions are as indicated by arrows in Fig. 1 and Fig. 2. The directions relating to the front and rear are the sub-scanning direction (transfer medium conveyance direction), and the directions relating to the left and right are the main scanning direction (head movement direction).

[0053] As shown in FIG. 1 , the image forming system 100 includes an image forming apparatus 1 including an ejection liquid storage unit 10, a control unit 30, an operation panel 40, and a discharge mechanism 60, a drying device 70, and a contact heating device 80. The image forming apparatus 1 also includes a discharge unit 20 inside its housing. The discharge mechanism 60 discharges a roll of transfer medium F having an ink-receiving layer in the sub-scanning direction. The roll of transfer medium F may be, for example, a roll of film having a length of several meters or more wound into a roll. The configuration of the transfer medium F is not limited to this. For example, a cut film cut to a predetermined size, such as A4 size or A3 size, may also be used as the transfer medium F. The ink-receiving layer of the transfer medium F is not particularly limited and may be one commonly used in the technical field of the present disclosure.

[0054] The image forming apparatus 1 is an inkjet printing apparatus that ejects droplets of the ink and adhesive liquid from an ejection unit 20 onto a transfer medium F. The ejection unit 20 is an inkjet head of a line head type or a serial head type. In the image forming apparatus 1, the droplets are ejected onto the transfer medium F based on image data to form an image.

[0055] The ejection liquid storage section 10 is capable of storing the ejection liquid. Examples of the ejection liquid include the ink and the adhesive liquid. However, the ejection liquid storage section 10 includes an ink storage section capable of storing the ejection liquid of the ink and an adhesive liquid storage section capable of storing the ejection liquid of the adhesive liquid, each of which is a separate component.

[0056] 2 , the image forming apparatus 1 includes, for example, a plurality of serial head type ejection units 20, a platen 22, a plurality of tanks 11, a conveying unit 51, and a scanning unit 52. The ejection units 20, the platen 22, the tanks 11, the conveying unit 51, and the scanning unit 52 are housed within the image forming apparatus 1.

[0057] The ejection unit 20 includes an ink ejection unit (first head) 20a and an adhesive liquid ejection unit (second head) 20b. The ink ejection unit 20a ejects the ink contained in the ink storage unit onto a transfer medium F having an ink-receiving layer using an inkjet system. The ink ejection unit 20a may include a color head that ejects color inks and a white head that ejects white ink onto the color inks. The adhesive liquid ejection unit 20b ejects the adhesive liquid contained in the adhesive liquid storage unit onto the ink on the transfer medium F using an inkjet system. However, the ejection unit 20 in the image forming apparatus 1 is not limited to one in which the ink is ejected from the ink ejection unit 20a and the adhesive liquid is ejected from the adhesive liquid ejection unit 20b. The ejection unit 20 in the image forming apparatus 1 may, for example, eject the ink from at least one nozzle provided in one head and eject the adhesive liquid from another nozzle, i.e., one ejection unit may eject both the ink and the adhesive liquid.

[0058] 2, for example, the ink discharge unit 20a located in the front of the image forming apparatus 1 is the color head, and the ink discharge unit 20a located in the rear of the image forming apparatus 1 is the white head. When the ink discharge unit 20a includes the white head, for example, the white head is arranged in the sub-scanning direction relative to the color heads. Furthermore, although the white head is arranged in the main scanning direction relative to the adhesive liquid discharge unit 20b, it may also be arranged in the sub-scanning direction relative to the adhesive liquid discharge unit 20b. Furthermore, the color heads may be arranged in the sub-scanning direction relative to the white head and the adhesive liquid discharge unit 20b. Furthermore, the ink discharge unit 20a may be arranged in the main scanning direction relative to the adhesive liquid discharge unit 20b. When the ink discharge unit 20a is arranged in the main scanning direction relative to the adhesive liquid discharge unit 20b, for example, the color head, the white head, and the adhesive liquid discharge unit 20b may all be arranged in the main scanning direction, or the color head may be arranged in the main scanning direction relative to the adhesive liquid discharge unit 20b, and the white head may be arranged in the sub-scanning direction relative to the color head and the adhesive liquid discharge unit 20b.

[0059] The platen 22 supports the transfer medium F. The platen 22 defines the distance between the transfer medium F placed on the upper surface of the platen 22 and the ejection unit 20 placed opposite the transfer medium F. The tanks 11 are containers that store the ink or the adhesive liquid, and the number of tanks 11 may be the same as the number of types of the ink and the adhesive liquid. For example, the tanks 11 may have a first tank 11a that stores each of the color inks and white ink as the ink, and a plurality of second tanks 11b that store the adhesive liquid.

[0060] Examples of the color ink include cyan ink, yellow ink, magenta ink, black ink, red ink, green ink, and blue ink. Examples of the white ink include white ink.

[0061] The first tank 11a stores the ink and is connected to the ink discharge unit 20a via a first flow path 12a. The ink is supplied from the first tank 11a to the ink discharge unit 20a via the first flow path 12a. The second tank 11b stores the adhesive liquid and is connected to the adhesive liquid discharge unit 20b via the second flow path 12b. The adhesive liquid is supplied from the second tank 11b to the adhesive liquid discharge unit 20b via the second flow path 12b. The first flow path 12a and the second flow path 12b are formed of, for example, rubber tubes or plastic tubes.

[0062] The transfer medium F discharged by the discharge mechanism 60 is transported, for example, backward in the sub-scanning direction by the transport unit 51. The transport unit 51 has, for example, two pairs of transport rollers 54, a pair of presser members 53, and a transport motor (not shown). One set of transport rollers 54 and the other set of transport rollers 54 are arranged to sandwich the platen 22 in the sub-scanning direction. Each set of transport rollers 54 is arranged to sandwich the transfer medium F. A transport motor is connected to one of the transport rollers 54 in each set. The transport motor drives the transport rollers 54 to rotate around their axes, thereby transporting the transfer medium F supported by the platen 22 backward in the sub-scanning direction. Note that the transfer medium F may also be transported forward in the sub-scanning direction. When discharging the transfer medium F forward, the discharge mechanism 60 may, for example, return the transfer medium F discharged by the discharge mechanism 60 to the forward direction in the sub-scanning direction.

[0063] The scanning unit 52 includes, for example, a carriage 71, a pair of guide rails 72, a scanning motor 73, an endless belt 74, and a pulley 75. The pair of guide rails 72 extend above the platen 22 along the main scanning direction. The carriage 71 supports the discharge unit 20 and is supported by the guide rails 72 so as to be movable in the main scanning direction. The endless belt 74 is connected to the carriage 71 while extending in the main scanning direction, and is also connected to the scanning motor 73 via a pulley 75. When the scanning motor 73 is driven, the endless belt 74 operates, causing the carriage 71 to reciprocate in the main scanning direction along the guide rails 72. Therefore, the discharge unit 20 supported by the carriage 71 is capable of reciprocating in the main scanning direction.

[0064] 1, an operation panel 40 having buttons 41 and a display unit 42 is provided at the front right end of the image forming apparatus 1. The display unit 42 is, for example, a liquid crystal display. The buttons are used to input an image formation start signal to the control unit 30. In addition to or instead of the buttons, the display unit 42, which is, for example, a touch panel, may accept user input and input the image formation start signal to the control unit 30. A discharge mechanism 60 and an opening 50 through which the roll-shaped transfer medium F discharged from the discharge mechanism 60 enters and leaves the housing of the discharge unit 20 are provided on the front wall of the housing.

[0065] FIG. 3 is a block diagram showing a schematic configuration of an image forming system 100 according to the present disclosure. First, a layered liquid layer L1 made of the ink ejected from the ink ejection unit 20a is formed on the transfer medium F. Next, a layered liquid layer L2 made of the adhesive liquid ejected from the adhesive liquid ejection unit 20b is formed on the liquid layer L1. The liquid layers L1 and L2 are then dried by a drying device 70, forming an image on the transfer medium F. The drying device 70 performs the drying process by, for example, heat drying, air drying, or a combination of these. The drying process by the drying device 70 forms an image on the transfer medium F. The image is transferred to a print medium M by a contact heating device 80, forming an image on the print medium M. After the drying process, the contact heating device 80 applies heat and pressure to adhere the image formed by the ink to the print medium. Specifically, the contact heating device 80 applies heat and pressure to transfer the image S1 on the transfer medium F, to which the dried adhesive liquid (hereinafter sometimes referred to as "adhesive S2") has been applied, to the print medium M. To this end, the contact heating device 80 includes, for example, a lower iron 101, an upper iron 102, and a heater mounted within the upper iron 102. The print medium M is placed on the lower iron 101, and the transfer medium F is placed at a desired position on the print medium M. At this time, the transfer medium F is placed with the main surface on which the image has been formed facing downward (i.e., the main surface faces the print medium M). An example of the contact heating device 80 is a heat press device. In this state, the upper iron 102 descends, and the print medium M and transfer medium F are sandwiched between the lower iron 101 and the upper iron 102. The heater is then activated to heat the print medium M and transfer medium F. This melts the adhesive S2, and the image S1 on the transfer medium F is transferred to the print medium M. The print medium M may be, for example, fabric or paper, and is particularly required to have washing durability after image formation.

[0066] 4 is a block diagram showing an example of the configuration of the control unit of the image forming apparatus 1 of the present disclosure. The control unit 30 is electrically connected to a central processing unit (e.g., a CPU (Central Processing Unit)) 37, a ROM (Read Only Memory) 38, a RAM (Random Access Memory) 39, an input interface 35, and an output interface 30 via a bus 31. Buttons 41 and the like are electrically connected to the input interface 35. The output interface 42 is electrically connected to the ejection unit 20, a conveyance unit 51, a scanning unit 52, a display unit 42, and the like via drive circuits 81 to 84, respectively.

[0067] The CPU 37 performs various calculations and processes based on signals input by the buttons 41 and various programs and data stored in the ROM 38 and RAM 39. The CPU 37 then transmits the data and the like to each component of the discharge unit 20 via the output interface 36. The RAM 39 is a readable / writable volatile storage device, and stores the results of various calculations performed by the CPU 37.

[0068] The control unit 30 causes the ink ejection unit 20a to eject the ink, and also causes the adhesive ejection unit 20b to eject the adhesive.

[0069] When the control unit 30 acquires information about the transfer medium F, the control unit 30 may control the timing of ejecting the ink and the adhesive liquid in accordance with the acquired information.

[0070] The ink and adhesive liquid are ejected onto the transfer medium F using the image forming apparatus 1 of the present disclosure, for example, as follows. First, the ink is applied (ejected) onto the transfer medium F from the ink ejection unit 20a. Specifically, while the platen 22 and the ejection unit 20 are transported by the transport unit 51 and the scanning unit 52, the ink ejection unit 20a prints an image using the ink at an image formation location on the transfer medium F. At least one of the ROM 38 and RAM 39 of the control unit 30 of the image forming apparatus 1 stores, for example, various image data created by software and various data for each type of transfer medium F. When an operator instructs printing, the image data is sent to the ink ejection unit 20a via the output interface 36, and the ink ejection unit 20a ejects the ink based on the image data to print onto the transfer medium F held on the platen 22. Furthermore, the adhesive liquid ejection unit 20b ejects the adhesive liquid onto the ink on the transfer medium F held on the platen 22 based on the image data.

[0071] The image forming apparatus 1 may further include a storage unit (not shown). The storage unit is a memory accessible from the control unit 30 and includes RAM and ROM. The RAM temporarily stores various data such as image data created by the control unit 30. The ROM stores an image forming program, a printing program, predetermined data, and the like. The image forming program may be downloaded, for example, via a predetermined communication network and stored in the storage unit. Alternatively, the image forming program stored in a storage medium such as a CD-ROM or USB flash memory may be stored in the storage unit via a reading unit.

[0072] The image forming apparatus 1 is provided with a communication interface (not shown), and receives image data transmitted from other apparatuses via the communication interface.

[0073] In this state, the upper iron 102 descends, and the print medium M and transfer medium F are sandwiched between the lower iron 101 and the upper iron 102. The heater is then driven to heat the print medium M and transfer medium F. This melts the adhesive S2, and the image S1 on the transfer medium F is transferred to the print medium M.

[0074] Next, the image forming method of the present disclosure will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the steps in the image forming method of the present disclosure. As described above, the image forming method includes an ink ejection step, an adhesive liquid ejection step, a drying step, and a contact heating step.

[0075] The ink ejection step (S11) includes ejecting the ink onto the transfer medium by an inkjet method, and is performed by, for example, the ink ejection unit 20a.

[0076] The adhesive liquid ejection step (S12) includes ejecting the adhesive liquid onto the ink on the transfer medium by an inkjet method. The adhesive liquid ejection step (S12) is performed, for example, by the adhesive liquid ejection unit 20b described above. The amount of adhesive liquid ejected is not particularly limited, but for example, if the print medium is a fabric or the like, it is an amount that can sufficiently fill in the unevenness of the fabric. By ejecting the adhesive liquid in an amount that can sufficiently fill in the unevenness of the fabric, transfer defects are less likely to occur when the transfer medium is peeled off.

[0077] The drying step (S13) includes a step of drying the transfer medium onto which the adhesive liquid has been ejected. The drying step (S13) is performed, for example, by the drying section (drying device) 70 described above. The drying temperature in the drying step (S13) may be, for example, 100°C or less, 80°C or less, or 60°C or less. The drying time in the drying step (S13) may be, for example, 3.5 minutes or less, or 2 minutes or less. By setting the drying temperature and drying time as described above, excessive progress of the crosslinking reaction between the crosslinking agent and the resin particles is suppressed.

[0078] The contact heating step (S14) includes a step of applying heat and pressure after the drying to adhere the image formed by the ink to the print medium. The contact heating step (S14) is performed, for example, by the aforementioned contact heating unit (contact heating device) 80. The heating temperature in the contact heating step (S14) may be changed appropriately depending on, for example, the type of print medium. When the print medium is a cotton fabric, the heating temperature may be, for example, 185°C or less. When the print medium is a polyester fabric, the heating temperature may be, for example, 130°C or less. Setting the heating temperature depending on the type of print medium can avoid heat damage to the fibers constituting the fabric and detachment of the dye (sublimation transfer) due to the heating.

[0079] The image forming method of the present disclosure can be implemented using, for example, the image forming system described above. However, the image forming method of the present disclosure is not limited to use with the image forming system described above.

[0080] Next, examples of the present disclosure will be described together with comparative examples. Note that the present disclosure is not limited or restricted by the following examples and comparative examples.

[0081] [Examples 1 to 9 and Comparative Examples 1 to 5] The components in Tables 1 and 2 were charged into a stirring vessel while rotating a stirring bar and mixed together, thereby obtaining adhesive solutions of Examples 1 to 9 and Comparative Examples 1 to 5 containing the components in Tables 1 and 2.

[0082] For the adhesive solutions of Examples 1 to 9 and Comparative Examples 1 to 5, (a) measurement of storage modulus E', (b) evaluation of transferability, and (c) evaluation of washing fastness were carried out by the following methods.

[0083] (a) Measurement of storage modulus E' The adhesive solution was dropped onto a Teflon (registered trademark) petri dish and dried in a thermostatic chamber at 100°C for 6 hours to obtain a coating having an average thickness of 0.4 mm. The obtained coating was further cut into a rectangular shape with a width of 10 mm to prepare a test piece for measuring the storage modulus E'.

[0084] The prepared test piece was set in a dynamic viscoelasticity measuring device (TA Instruments "RSA-G2") at 20°C and then cooled to -60°C. After reaching -60°C, the dynamic viscoelasticity was measured under the following measurement conditions. The obtained measurement data was taken as "storage modulus E' at 110°C and "storage modulus E' at 25°C". Measurement temperature range: -60°C to 180°C Heating rate: 2.5°C / min Frequency: 1 Hz Initial strain: 0.1% Clamp distance: 10 mm

[0085] (b) Transferability Evaluation Using a printer (Brother Industries, Ltd., "GTX Pro B"), inks (Brother Industries, Ltd., "GCX-4C02-1, GCX-4M02-1, GCX-4Y02-1, GCX-4K02-1, GCX-4W02") and adhesive solutions of the Examples and Comparative Examples were ejected onto a transfer medium (Schultz, "DTF Premium Film") using a printer (Brother Industries, Ltd., "GTX Pro B"). After ejecting the ink and adhesive solution, the adhesive solution was dried so that its weight change rate X satisfied condition 1 (the aforementioned formula (1)) or condition 2 (the aforementioned formula (2)), yielding an intermediate transfer recording medium. The intermediate transfer recording medium was then heat-pressed onto a cotton T-shirt (COTTON HERITAGE, Inc., "MC1082") at 185°C, 65 psi, and 300 seconds. After the cotton T-shirt and transfer medium had sufficiently cooled, the transfer medium was peeled off, and the image was transferred onto the cotton T-shirt. The transfer state after peeling off the transfer medium was judged according to the following criteria to evaluate the transferability. The weight change rate X was calculated based on the following formula (3): X = (Wb - Wc) / (Wb - Wa) x 100 (3) In formula (3), Wa is the weight of the transfer medium, Wb is the weight of the transfer medium to which the ink and adhesive liquid have been applied before drying, and Wc is the weight of the transfer medium to which the ink and adhesive liquid have been applied after drying.

[0086] Transferability evaluation Evaluation criteria A: The image was transferred from the transfer medium to the T-shirt, and there was no bleed-through to the back of the T-shirt. B: The image was transferred from the transfer medium to the T-shirt, but there was bleed-through to the back of the T-shirt. C: The image was not transferred from the transfer medium to the T-shirt, or image defects occurred due to poor transfer.

[0087] (c) Evaluation of Washing Fastness A washing test was carried out on a cotton T-shirt to which an image had been transferred in the same manner as in "(b) Evaluation of Transferability." The washing test was carried out for one cycle in accordance with the American standard AATCC 61 II A method. The image after washing was evaluated for washing fastness according to the following criteria.

[0088] Evaluation of washing fastness Evaluation criteria A: The image was not peeled off and was not cracked. B: The image was not peeled off but was cracked. C: The image was peeled off or cracked.

[0089] The compositions of the adhesive solutions of Examples 1 to 9 and Comparative Examples 1 to 5 and the evaluation results are shown in Tables 1 and 2.

[0090]

[0091]

[0092] As shown in Table 1, in Examples 1 to 9, the transferability was good, being "B" when condition 1 was satisfied, and "A" when condition 2 was satisfied. The washing fastness was also good, being "B" or higher. Furthermore, under the condition that the storage modulus E' at 25°C was 8.1 x 10 Pa or less, the washing fastness was all "A," being particularly good.

[0093] On the other hand, as shown in Table 2, in Comparative Examples 1 to 5, the transferability was rated "C" under both Condition 1 and Condition 2. In addition, the washing fastness was also rated "C" in all cases.

[0094] The present disclosure may be partially or entirely described as, but is not limited to, the following notes. (Note 1) An adhesive liquid that is ejected from an ejection head onto ink on a transfer medium having an ink-receiving layer, and that adheres an image formed by the ink to the print medium by applying heat and pressure after drying, the adhesive liquid comprising water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, wherein a weight change rate X before and after the drying satisfies the following formula (1) or (2), and wherein a storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before the application of the heat and pressure is 5.4 x 106 Pa or less. X<A (1) A≦X<B (2) In formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid. (Supplementary Note 2) The adhesive liquid according to Supplementary Note 1, wherein the weight change rate X satisfies the formula (2). (Supplementary Note 3) The adhesive liquid according to Supplementary Note 1 or 2, wherein a coating obtained by drying the adhesive liquid has a storage modulus E' at 25°C of 8.1 x 106 Pa or less before the application of the heat and the pressure. an adhesive liquid storage unit; an adhesive liquid discharge unit that discharges the ink stored in the ink storage unit onto a transfer medium by an inkjet system; an adhesive liquid storage unit; an adhesive liquid discharge unit that discharges the adhesive liquid stored in the adhesive liquid storage unit onto the ink on the transfer medium by an inkjet system; a drying unit that dries the transfer medium onto which the adhesive liquid has been discharged; and a contact heating unit that applies heat and pressure after the drying to adhere an image formed by the ink to a print medium, wherein the adhesive liquid contains water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, and a weight change rate X before and after the drying satisfies the following formula (1) or (2), and a storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before the application of the heat and the pressure is 5.4 x 106 Pa or less.X<A (1) A≦X<B (2) In the formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in the formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid. (Appendix 5) An image forming method comprising an ink discharging step, an adhesive liquid discharging step, a drying step, and a contact heating step, wherein the ink discharging step comprises discharging ink onto a transfer medium by an inkjet system, the adhesive liquid discharging step comprises discharging adhesive liquid onto the ink on the transfer medium by an inkjet system, the drying step comprises drying the transfer medium onto which the adhesive liquid has been discharged, and the contact heating step comprises applying heat and pressure after the drying to adhere an image formed by the ink to a print medium, the adhesive liquid comprising water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, a weight change rate X before and after the drying satisfies the following formula (1) or (2), and a storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before the application of the heat and the pressure is 5.4 × 106 Pa or less. X<A (1) A≦X<B (2) In the formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in the formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

[0095] As described above, according to the adhesive liquid, image forming system, and image forming method of the present disclosure, even when an intermediate transfer recording medium is produced using the adhesive liquid, the transferability of the printing layer and the washing fastness of the printing medium after image transfer are good.

[0096] REFERENCE SIGNS LIST 100 Image forming system 1 Image forming apparatus 10 Discharge liquid storage section 20 Discharge section 30 Control section 40 Operation panel 50 Opening 60 Discharge mechanism F Transfer medium

Claims

1. An adhesive liquid that is ejected from an ejection head onto ink on a transfer medium having an ink-receiving layer, and that adheres an image formed by the ink to the print medium by applying heat and pressure after drying, the adhesive liquid comprising water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, wherein the weight change rate X before and after the drying satisfies the following formula (1) or (2), and the storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before applying the heat and pressure is 5.4 x 106 Pa or less: X<A (1) A≦X<B (2) In formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

2. The adhesive liquid according to claim 1, wherein the weight change rate X satisfies the formula (2).

3. The adhesive according to claim 1 or 2, wherein the storage modulus E' of the coating obtained by drying the adhesive at 25°C before the application of heat and pressure is 8.1 x 106 Pa or less.

4. An image forming system comprising: an ink storage section; an ink ejection section that ejects ink stored in the ink storage section onto a transfer medium by an inkjet system; an adhesive liquid storage section; an adhesive liquid ejection section that ejects adhesive liquid stored in the adhesive liquid storage section onto the ink on the transfer medium by an inkjet system; a drying section that dries the transfer medium onto which the adhesive liquid has been ejected; and a contact heating section that applies heat and pressure after the drying to adhere an image formed by the ink to a print medium, wherein the adhesive liquid contains water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, and the weight change rate X before and after the drying satisfies the following formula (1) or (2), and the storage modulus E' at 110°C of a coating obtained by drying the adhesive liquid before the application of the heat and the pressure is 5.4 x 106 Pa or less. X<A (1) A≦X<B (2) In the formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in the formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

5. An image forming method comprising an ink ejection process, an adhesive liquid ejection process, a drying process, and a contact heating process, wherein the ink ejection process comprises ejecting ink onto a transfer medium using an inkjet method, the adhesive liquid ejection process comprises ejecting adhesive liquid onto the ink on the transfer medium using an inkjet method, the drying process comprises drying the transfer medium onto which the adhesive liquid has been ejected, and the contact heating process comprises applying heat and pressure after the drying to adhere the image formed by the ink to the print medium, the adhesive liquid comprises water, resin particles, an organic solvent, a crosslinking agent, and a surfactant, the weight change rate X before and after the drying satisfies the following formula (1) or (2), and the storage modulus E' at 110°C of the coating obtained by drying the adhesive liquid before the application of the heat and the pressure is 5.4 x 106 Pa or less. X<A (1) A≦X<B (2) In the formulas (1) and (2), A is the weight ratio of the water in the total amount of the adhesive liquid, and in the formula (2), B is the weight ratio of the water and the organic solvent in the total amount of the adhesive liquid.

Images