Conveyance device, printer and adhesive coating method

Abstract

To provide a conveyance device, a printer and an adhesive coating method which can form an adhesive layer having uniform thickness and non-uniform adhesiveness on a conveyance belt.SOLUTION: A conveyance device includes a conveyance belt for conveying a recording medium, and a blade for leveling a coating liquid of an aqueous adhesive which is supplied to a coating surface on the recording medium side of the conveyance belt and contains water and a resin on the coating surface, wherein the blade is mainly composed of a resin material. The blade extends in a width direction of the conveyance belt, and is separated from the conveyance belt by a predetermined distance when the coating liquid is leveled.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a conveying device, a printing device, and an adhesive application method. [Background technology]

[0002] For example, a printing device that prints by applying ink onto a recording medium is known, as shown in Patent Document 1. The printing device described in Patent Document 1 includes a conveyor belt that conveys the recording medium, and a printing unit that reciprocates in a direction intersecting the conveyance direction of the recording medium and has a large number of nozzles that eject ink onto the recording medium being conveyed.

[0003] In addition, an adhesive layer is formed on the surface of the conveyor belt that comes into contact with the recording medium, which allows the recording medium to be stably conveyed while being adhesively held thereon. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-116092 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, the adhesive constituting the adhesive layer is an adhesive obtained using an organic solvent. Therefore, sufficient consideration must be given to safety when handling the adhesive coating solution during production and application to the conveyor belt. In particular, when applying the adhesive coating solution, there are many restrictions on the surrounding environment, such as the necessity of sufficient ventilation. Therefore, using an aqueous adhesive could be considered, but simply applying the aqueous adhesive using the same method as in the past may not be able to apply the aqueous adhesive evenly and may result in uneven adhesion. [Means for solving the problem]

[0006] The conveying device of the present invention comprises: a conveying belt for conveying a recording medium; a blade for leveling a coating liquid of an aqueous adhesive containing water and a resin, which is supplied to a coating surface of the conveyor belt on the recording medium side, on the coating surface; The blade is mainly made of a resin material.

[0007] The printing device of the present invention comprises: an inkjet head that performs printing by ejecting ink onto the recording medium being transported by the transport belt.

[0008] The adhesive application method of the present invention includes a supplying step of supplying an aqueous adhesive coating solution containing water and a resin to a coating surface of a conveyor belt that conveys a recording medium, the coating surface being on the recording medium side; and a leveling step of leveling the coating liquid supplied to the coating surface on the coating surface with a blade made mainly of a resin material. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a conveying device and a printing device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a state in which the conveying device shown in FIG. 1 is performing a leveling process. [Figure 3] FIG. 3 is a flowchart illustrating an example of an adhesive application method according to an embodiment of the present invention. [Figure 4] FIG. 4 is Table 1 showing the blade materials and water-based adhesives used in the examples and the evaluation results thereof. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A conveying device, a printing device, and an adhesive application method according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0011] First Embodiment Fig. 1 is a schematic diagram of a conveying device and a printing device according to an embodiment of the present invention. Fig. 2 is a diagram showing a state in which the conveying device shown in Fig. 1 is performing a leveling process. Fig. 3 is a flowchart for explaining an example of an adhesive application method according to an embodiment of the present invention.

[0012] For ease of explanation, in the following, in Figures 1 and 2, the x-axis, y-axis, and z-axis are shown as three mutually orthogonal axes. The x-axis is an axis along one of the horizontal directions (the width direction of the conveyor belt), the y-axis is an axis along the horizontal direction and perpendicular to the x-axis (the running direction of the conveyor belt), and the z-axis is an axis along the vertical direction (the up-down direction in the figure). In addition, the tip side of each arrow shown in the figure is referred to as the "positive side (+ side)" and the base side is referred to as the "negative side (- side)." In addition, the upper side of Figures 1 and 2 is referred to as "top" or "upper," and the lower side is referred to as "bottom" or "lower."

[0013] As shown in Figures 1 and 2, the printing device 1 includes a conveying device 2 having a conveying belt 21 that conveys the recording medium W, a feeding device 3 that feeds out the long recording medium W wound in a roll, a winding device 4 that winds up the printed recording medium W, a printing unit 5 that applies ink to the recording medium W being conveyed by the conveying belt 21 to perform printing, and an ink drying unit 6 that dries the ink on the recording medium W.

[0014] In this embodiment, the direction perpendicular to the transport direction in which the recording medium W is transported is the x-axis direction, the direction parallel to the transport direction is the y-axis direction, and the direction perpendicular to the x-axis and y-axis directions is the z-axis direction.

[0015] A printable material can be used as the recording medium W. The printable material refers to fabrics, clothing, and other clothing products that are the subject of printing. Fabrics include woven fabrics, knitted fabrics, and nonwoven fabrics made from natural fibers such as cotton, silk, and wool, chemical fibers such as nylon, and composite fibers that combine these. Clothing and other clothing products also include sewn items such as T-shirts, handkerchiefs, scarves, towels, carrier bags, cloth bags, curtains, sheets, bedspreads, and other furniture, as well as fabrics that exist as parts before and after cutting and before sewing.

[0016] The recording medium W is not limited to the above-mentioned printing materials, but may also include, for example, paper specifically designed for inkjet printing, such as plain paper, wood-free paper, and glossy paper. The recording medium W may also be, for example, a plastic film that has not been surface-treated for inkjet printing, i.e., that does not have an ink-absorbing layer, or a substrate such as paper coated with plastic or with a plastic film attached. Examples of such plastics include, but are not limited to, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

[0017] The conveying device 2 has a driving roller 22 and a driven roller 23 arranged at a distance from each other in the y-axis direction, a conveying belt 21 stretched between the driving roller 22 and the driven roller 23 and supporting the recording medium W on its upper surface (support surface), and tensioners 24, 25 that apply tension to the recording medium W between the driving roller 22 and the driven roller 23.

[0018] A motor (not shown) is connected to the driving roller 22, and the driving roller 22 can be driven to rotate by the operation of the motor. The rotational force of the driving roller 22 is transmitted to the driven roller 23 via the conveyor belt 21, and the driven roller 23 can rotate in conjunction with the driving roller 22.

[0019] The conveyor belt 21 is an endless belt on whose front surface an adhesive layer having adhesive properties is formed. A portion of the recording medium W is adhesively fixed to this adhesive layer, and the recording medium W is conveyed toward the + side in the y-axis direction. During this conveyance, the desired printing is performed on the recording medium W. After printing, the recording medium W is peeled off from the conveyor belt 21. The adhesive layer is formed by supplying an adhesive coating liquid 100 from a coating liquid supply unit 8, as shown in FIG. 2. The surface of the conveyor belt 21 that comes into contact with the recording medium W is a coating surface 210 on which the coating liquid 100 is applied.

[0020] Similar to the driving roller 22 and the driven roller 23, the tensioners 24 and 25 are also arranged spaced apart from each other in the y-axis direction.

[0021] The tensioner 24 can sandwich the recording medium W together with the conveyor belt 21 between it and the drive roller 22, and the tensioner 25 can sandwich the recording medium W together with the conveyor belt 21 between it and the driven roller 23. As a result, the recording medium W, to which an appropriate tension is applied by the tensioners 24 and 25, is adhesively fixed to the conveyor belt 21 while being tensioned, and is conveyed. In this state, the recording medium W is less likely to develop wrinkles, sagging, etc. during conveyance, and therefore, when printing is performed, the printing is appropriate and of high quality.

[0022] The payout device 3 is disposed upstream of the transport device 2 in the feeding direction of the recording medium W, i.e., on the negative side in the y-axis direction. The payout device 3 has a payout roller (payout reel) 31 around which the recording medium W is wound in a roll and which pays out the recording medium W, and a tensioner 32 which applies tension to the recording medium W between the payout roller 31 and the transport device 2. A motor (not shown) is connected to the payout roller 31, and the payout roller 31 can be driven to rotate by the operation of the motor.

[0023] The winding device 4 is disposed downstream of the driven roller 23 in the feeding direction of the recording medium W, i.e., on the + side in the y-axis direction, relative to the conveying device 2. The winding device 4 has a winding roller 41 that winds the recording medium W into a roll, and tensioners 42, 43, and 44 that apply tension to the recording medium W between the winding roller 41 and the conveying device 2. A motor (not shown) is connected to the winding roller 41, and operation of the motor drives the winding roller 41 to rotate. The tensioners 42, 43, and 44 are disposed in this order at intervals in a direction away from the winding roller 41.

[0024] The printing unit 5 includes a carriage unit 52 having a plurality of inkjet heads 51 that perform recording by ejecting ink toward the recording medium W, and an X-axis table (not shown) that supports the carriage unit 52 so that the carriage unit 52 can move in the x-axis direction. Each inkjet head 51 includes, for example, a head body having an internal flow path formed therein that is filled with ink, and a large number of nozzle groups each having an opening.

[0025] The head body is provided with a piezoelectric element (piezoelectric body) corresponding to each ejection nozzle, and when a voltage is applied to the piezoelectric element, ink is ejected as droplets from the nozzle group.

[0026] When not ejecting ink, the inkjet head 51 waits at a standby position that is positioned away from the recording medium W (conveyor belt 21) in the x-axis direction when viewed from the z-axis direction.

[0027] In the printing device 1, the recording medium W fed by the feeding device 3 is intermittently fed in the positive direction of the y axis while being adhesively fixed by the conveyor belt 21, and ink is ejected from the nozzle group onto the fixed recording medium W while the carriage unit 52 is reciprocated in the x axis direction. In this way, a desired image pattern is formed and printed on the recording medium W. The image pattern may be printed in multiple colors or in a single color.

[0028] The inks contain water as a solvent and dyes or pigments as colorants, and come in four colors, for example, cyan (C), magenta (M), yellow (Y), and black (K). Each color of ink is ejected independently from the inkjet head 131.

[0029] As shown in FIG. 1, the ink drying unit 6 is located downstream of the printing unit 5 in the transport direction of the recording medium W, i.e., on the +y-axis direction side, between the transport device 2 and the winding roller 41 of the winding device 4.

[0030] The ink drying unit 6 has a chamber 61 and a coil 62, which is a heat source (heater), arranged inside the chamber 61. The coil 62 is made of, for example, nichrome wire, and is configured as a heating element that generates heat when power is supplied. The heat generated by the coil 62 can dry the ink on the recording medium W passing through the chamber 61.

[0031] In such a printing apparatus 1, when printing is not being performed, an adhesive is periodically supplied onto the conveyor belt 21 to form an adhesive layer. In the printing apparatus 1, an adhesive layer is formed on the surface of the conveyor belt 21 on the recording medium W side by the coating liquid supply unit 8, the blade 9, and the adhesive drying unit 10 provided in the conveyor device 2.

[0032] Conventionally, adhesives constituting adhesive layers have generally been made by dissolving hydrophobic resins in organic solvents so as to withstand water washing. Recently, however, there has been a demand for water-based adhesives that use less organic solvents in order to reduce environmental impact and improve working environments. However, water-based adhesives have poor durability, and the adhesive strength of the adhesives applied to the surface of the transport member tends to gradually decrease with washing, making it necessary to apply new adhesive after each washing.

[0033] 1. Water-based adhesive (water-based adhesive composition) In the present invention, the aqueous pressure-sensitive adhesive is an aqueous pressure-sensitive adhesive composition containing a resin and water. 1.1.Resin The resin is not particularly limited, but for example, a (meth)acrylic resin can be used.

[0034] The inclusion of a (meth)acrylic resin can improve the adhesive strength and durability of the adhesive layer. The (meth)acrylic resin may be a water-soluble resin or an emulsion dispersed in an aqueous catalyst. These are collectively referred to as (meth)acrylic resin in this embodiment. The use of a (meth)acrylic resin can reduce the environmental burden caused by organic solvents and also tends to further improve the peelability of the adhesive layer from the recording medium W, particularly fabric.

[0035] The (meth)acrylic resin is not particularly limited as long as it is a polymer obtained by polymerizing a (meth)acrylic monomer such as (meth)acrylic acid or a (meth)acrylic acid ester as one component. Examples include homopolymers obtained from (meth)acrylic monomers and copolymers of (meth)acrylic monomers with other monomers. More specific (meth)acrylic monomers are not particularly limited, but include (meth)acrylic monomers having an aliphatic group with 3 or less carbon atoms, such as methyl methacrylate (MMA), ethyl methacrylate (EMA), and n-propyl methacrylate (PMA); (meth)acrylic monomers having an aliphatic group with 4 or more carbon atoms, such as butyl methacrylate (BMA), butyl acrylate (BA), and 2-ethylhexyl acrylate (2EHA); and (meth)acrylic monomers having an aromatic group, such as styrene (St). Other monomers are not particularly limited, but include acrylamide and acrylonitrile.

[0036] The monomer contained in the (meth)acrylic resin is not particularly limited, but examples thereof include methyl methacrylate (MMA), ethyl methacrylate (EMA), n-propyl methacrylate (PMA), butyl methacrylate (BMA), styrene (St), butyl acrylate (BA), and 2-ethylhexyl acrylate (2EHA).

[0037] The combination of monomers is not particularly limited, but examples thereof include a combination containing at least ethyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate, a combination containing at least methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate, a combination containing at least n-propyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate, and a combination containing at least butyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate.

[0038] The aqueous pressure-sensitive adhesive composition contains at least a first (meth)acrylic resin and a second (meth)acrylic resin as (meth)acrylic resins, and the glass transition temperature Tg1 of the first (meth)acrylic resin is preferably higher than the glass transition temperature Tg2 of the second (meth)acrylic resin. By containing two types of (meth)acrylic resins having such different glass transition temperatures Tg, there is a tendency for the adhesive strength and durability to be improved, and for the effect of suppressing a decrease in adhesive strength during brushing to be further improved.

[0039] The glass transition temperature Tg1 of the first (meth)acrylic resin is not particularly limited, but is preferably −25 to 25° C., and more preferably −20 to 20° C. When the glass transition temperature Tg1 is in the above range, the adhesive strength tends to be further improved.

[0040] The glass transition temperature Tg2 of the second (meth)acrylic resin is not particularly limited, but is preferably −70 to −15° C., and more preferably −65 to −20° C. When the glass transition temperature Tg2 is in the above range, the decrease in adhesive strength during brushing tends to be further suppressed.

[0041] The difference |Tg1-Tg2| between the glass transition temperature Tg1 and the glass transition temperature Tg2 is preferably 10° C. or more and 50° C. or less, and more preferably 15° C. or more and 45° C. or less. When the difference |Tg1-Tg2| is in the above range, the adhesive strength and the effect of suppressing a decrease in adhesive strength during brushing tend to be further improved.

[0042] The glass transition temperature can be adjusted by the homopolymer glass transition temperature of the polymerizable compound used and the weight ratio of the polymerizable compound used. The glass transition temperature can be measured by a conventionally known method.

[0043] The monomer contained in the first (meth)acrylic resin is not particularly limited, but is preferably one containing at least ethyl methacrylate, butyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate, one containing at least ethyl methacrylate, styrene, butyl acrylate, and 2-ethylhexyl acrylate, one containing at least methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate, or one containing at least butyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate. Use of a first (meth)acrylic resin containing the above monomers tends to further improve adhesive strength and the effect of suppressing adhesive strength loss during brushing.

[0044] The first (meth)acrylic resin preferably contains, as a constituent unit, a (meth)acrylic monomer whose homopolymer has a glass transition temperature of 40° C. or higher. When the first (meth)acrylic resin contains the above-mentioned monomer, the adhesive strength of the adhesive layer and the effect of suppressing a decrease in adhesive strength during brushing tend to be further improved.

[0045] The content of the (meth)acrylic monomer having a homopolymer glass transition temperature of 40° C. or higher is preferably 20% by weight to 70% by weight, and more preferably 25% by weight to 65% by weight, relative to the total amount of the first (meth)acrylic resin. When the content of the (meth)acrylic monomer having a homopolymer glass transition temperature of 40° C. or higher is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing a decrease in adhesive strength during brushing tend to be further improved.

[0046] The monomer contained in the second (meth)acrylic resin is not particularly limited, but is preferably one containing at least ethyl methacrylate, butyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate, or one containing at least n-propyl methacrylate, butyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate. By using a second (meth)acrylic resin containing the above monomers, the adhesive strength and the effect of suppressing the adhesive strength decrease during brushing tend to be further improved.

[0047] The content of the first (meth)acrylic resin is preferably 50% by weight or more and 85% by weight or less, more preferably 53% by weight or more and 82% by weight or less, based on the total amount of the first (meth)acrylic resin and the second (meth)acrylic resin. When the content of the first (meth)acrylic resin is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing the decrease in adhesive strength during brushing tend to be further improved.

[0048] The content of the second (meth)acrylic resin is preferably less than 50% by weight, more preferably 10% to 48% by weight, of the total amount of the first (meth)acrylic resin and the second (meth)acrylic resin. When the content of the second (meth)acrylic resin is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing the decrease in adhesive strength during brushing tend to be further improved.

[0049] The content of the (meth)acrylic resin is preferably 20% by weight or more and 70% by weight or less, and more preferably 30% by weight or more and 60% by weight or less, relative to the total amount of the aqueous pressure-sensitive adhesive composition. When the content of the (meth)acrylic resin is 20% by weight or more, the adhesive strength and durability of the resulting pressure-sensitive adhesive layer tend to be further improved. Furthermore, when the content of the (meth)acrylic resin is 70% by weight or less, the application property and storage stability of the aqueous pressure-sensitive adhesive composition tend to be further improved. Note that the content relative to the total amount of the aqueous pressure-sensitive adhesive composition refers to the amount of solids.

[0050] The content of the first (meth)acrylic resin is preferably 10% by weight or more and 70% by weight or less, and more preferably 20% by weight or more and 60% by weight or less, based on the total amount of the aqueous pressure-sensitive adhesive composition. When the content of the first (meth)acrylic resin is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing the decrease in adhesive strength during brushing tend to be further improved.

[0051] The content of the second (meth)acrylic resin is preferably 50% by weight or less, and more preferably 1% by weight or more and 40% by weight or less, based on the total amount of the aqueous pressure-sensitive adhesive composition. When the content of the second (meth)acrylic resin is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing the decrease in adhesive strength during brushing tend to be further improved.

[0052] The aqueous pressure-sensitive adhesive composition may contain a resin other than the (meth)acrylic resin. Such other resins are not particularly limited, but examples thereof include urethane resins, silicone resins, and various elastomers (rubber-based materials).

[0053] The resin is not limited to the above-mentioned (meth)acrylic resin or a resin mainly composed of a (meth)acrylic resin, but may also include, for example, urethane resin, silicone resin, and various rubber materials.

[0054] 1.2. Tackifiers The aqueous pressure-sensitive adhesive composition preferably contains no or a small amount of a tackifier. When the aqueous pressure-sensitive adhesive composition contains no or a small amount of a tackifier, the adhesive strength of the adhesive layer and the effect of suppressing the decrease in adhesive strength during brushing tend to be more sustained. Typical examples of such tackifiers include rosin compounds, terpene compounds, and hydrocarbon resins. More specifically, examples of the compound include rosin-based compounds such as natural rosin, modified rosin, glycerol esters of natural rosin, glycerol esters of modified rosin, pentaerythritol esters of natural rosin, and pentaerythritol esters of modified rosin; terpene-based compounds such as copolymers of natural terpene, three-dimensional polymers of natural terpene, aromatic modified terpene resins, hydrogenated derivatives of aromatic modified terpene resins, terpene phenol resins, and terpene resins (monoterpene, diterpene, triterpene, polyperene, etc.); and hydrocarbon resins such as aliphatic petroleum hydrocarbon resins (C5 resins), hydrogenated derivatives of aliphatic petroleum hydrocarbon resins, aromatic petroleum hydrocarbon resins (C9 resins) such as styrene oligomers, and hydrogenated derivatives of aromatic petroleum hydrocarbon resins.

[0055] It is preferable that the composition does not contain a tackifier, or if it does contain one, it contains only a small amount. When a tackifier is contained, its content is not particularly limited, but is preferably 5 wt% or less, more preferably 4 wt% or less, and even more preferably 0.1 wt% to 3.8 wt% based on the total amount of the aqueous pressure-sensitive adhesive composition. When the tackifier content is within the above range, the adhesive strength of the resulting adhesive layer and the effect of suppressing a decrease in adhesive strength during brushing tend to be more sustained. From a similar perspective, the total content of compounds selected from the group consisting of rosin-based compounds, terpene-based compounds, and hydrocarbon resins is also preferably within the same range.

[0056] 1.3.Water The water content in the aqueous adhesive (coating liquid 100) is not particularly limited, but is preferably 30% by weight to 80% by weight, and more preferably 35% by weight to 70% by weight, which makes it easier to level the coating liquid 100 applied to the application surface 210 to a uniform thickness.

[0057] 1.4.Surfactants The aqueous pressure-sensitive adhesive composition may contain a surfactant. The surfactant is not particularly limited, but examples thereof include anionic surfactants, nonionic surfactants, and cationic surfactants.

[0058] Examples of anionic surfactants include alkyl sulfocarboxylates, alkyl diphenyl ether disulfonates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurines, alkyl sulfates such as ammonium lauryl sulfate and sodium lauryl sulfate, alkyl sulfate polyoxyalkyl ether sulfates, alkyl sulfate polyoxyethylene alkyl ether phosphates, rosin acid soap, castor oil sulfate esters, lauryl alcohol sulfate esters, alkylphenol phosphate esters, alkyl phosphate esters, alkylaryl sulfonates, diethyl sulfosuccinate, diethylhexyl cyrsulfosuccinate, and dioctyl sulfosuccinate.

[0059] Examples of nonionic surfactants include acetylene glycol surfactants, silicone surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil, propylene glycol fatty acid esters, glycerin fatty acid esters, polyglycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, alkyl polyglycosides, alkyl diethanolamides, and alkylamine oxides.Commercially available nonionic surfactants include, but are not limited to, Emulgen 123P, 430, and 1108 (product names of Kao Corporation), Newcol 1006, 1008, and 1020 (product names of Nippon Nyukazai Co., Ltd.), Noigen DL-0415, ET-116B, ET-106A, DH-0300, YX-400, and EA-160 (product names of Daiichi Kogyo Seiyaku Co., Ltd.).

[0060] Examples of cationic surfactants include alkylamine salts, fatty acid amidoamine salts, monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, trialkyl quaternary ammonium salts, benzalkonium quaternary ammonium salts, benzethonium chloride, and alkylpyridinium salts.

[0061] In this embodiment, among these, nonionic surfactants are preferred, and more specifically, alkyl ether-based nonionic surfactants are preferred. Use of such surfactants tends to maintain durability.

[0062] The content of the surfactant is preferably 1% by weight or more and 7% by weight or less, and more preferably 2% by weight or more and 6% by weight or less, based on the total amount of the aqueous pressure-sensitive adhesive composition.

[0063] 1.5. Organic Solvents From the viewpoint of reducing the environmental load and the influence on the human body, the aqueous pressure-sensitive adhesive composition in this embodiment preferably does not contain an organic solvent, or if it does contain an organic solvent, it contains only a small amount. Furthermore, if an organic solvent is contained, the content of the organic solvent is preferably 5.0 wt% or less, more preferably 2.5 wt% or less, based on the total amount of the aqueous pressure-sensitive adhesive composition. This reduces the environmental load and also reduces VOCs (volatile organic compounds) when the aqueous pressure-sensitive adhesive composition is used, which tends to further improve the working environment.

[0064] 1.6.Colorants The aqueous pressure-sensitive adhesive composition of this embodiment preferably does not contain a colorant, or if it does contain one, it contains only a small amount of colorant. Furthermore, if a colorant is contained, the content of the colorant is preferably 1.0 wt % or less, more preferably 0.5 wt % or less, based on the total amount of the aqueous pressure-sensitive adhesive composition. This clearly distinguishes the aqueous pressure-sensitive adhesive composition of this embodiment from compositions intended for coloring, such as ink compositions, textile printing pastes, and paints.

[0065] 1.7.Storage Modulus The aqueous pressure-sensitive adhesive composition of the present embodiment is intended to form a pressure-sensitive adhesive layer on the surface of a fabric-transporting member of an ink-jet printing apparatus. The pressure-sensitive adhesive layer obtained by the present embodiment has excellent adhesive strength and durability, and also has excellent mechanical properties as described below.

[0066] The storage modulus of the adhesive layer obtained in this embodiment at 23°C is 1.5 × 10 5 Pa or more 5.0×10 5 Pa or less, and 1.6 × 10 5 Pa or more 4.8×10 5 Pa or less is more preferable, and 2.0×10 5 Pa or more 4.5×10 5 It is more preferable that the storage modulus is 1.5×10 Pa or less. 5 By having a storage modulus of 5.0×10 Pa or more, it is possible to prevent the adhesive strength from decreasing when the adhesive surface is washed with water. 5 By ensuring that the viscosity is equal to or less than 100 Pa, the initial adhesive strength can be increased.

[0067] The method for forming the adhesive layer for measuring the storage modulus is not particularly limited. For example, the aqueous adhesive composition was applied to a 25 mm wide slide glass at room temperature to a thickness of 0.2 mm, and then dried under conditions of 50% humidity, 23°C, and 12 hours.

[0068] When an adhesive layer consisting solely of the first (meth)acrylic resin (hereinafter referred to as "first acrylic adhesive layer") is formed by the same method as in the case of the aqueous adhesive composition, the storage modulus of the first acrylic adhesive layer at 23°C is not particularly limited, but is preferably 1.0 × 10 5 ~8.0×10 5 Pa, and more preferably 1.6×10 5 ~7.6×10 5 Pa. When the storage modulus of the first acrylic adhesive layer is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing a decrease in adhesive strength during brushing tend to be further improved.

[0069] When an adhesive layer consisting only of the second (meth)acrylic resin (hereinafter referred to as "second acrylic adhesive layer") is formed by the same method as in the case of the aqueous adhesive composition, the storage modulus of the second acrylic adhesive layer at 23°C is, but is not particularly limited to, 6.0 × 10 5 Over 8.0 x 10 5 Pa or less, and 7.0 × 10 5 Over 7.5 x 10 5 It is more preferably not more than Pa. When the storage modulus of the second acrylic adhesive layer is within the above range, the adhesive strength of the adhesive layer and the effect of suppressing a decrease in adhesive strength during brushing tend to be further improved.

[0070] 1.8. Adhesive strength The adhesive strength at 23°C of the adhesive layer obtained according to this embodiment is not particularly limited, but is preferably 0.3 N / 50 mm or more and 3.0 N / 50 mm or less, more preferably 0.5 N / 50 mm or more and 2.0 N / 50 mm or less, and even more preferably 0.7 N / 50 mm or more and 1.8 N / 50 mm or less. Having the adhesive strength at 23°C within the above ranges further improves the adhesive strength of the adhesive layer and the effect of suppressing a decrease in adhesive strength during brushing.

[0071] 1.9.Viscosity The viscosity of the aqueous adhesive coating solution 100 at room temperature is not particularly limited, but is preferably 1 cps to 500 cps, more preferably 5 cps to 470 cps, even more preferably 10 cps to 450 cps, and particularly preferably 120 cps to 400 cps. This makes it easier to level the coating solution 100 applied to the application surface 210 to a uniform thickness, contributing to uniform film thickness and surface properties of the resulting adhesive layer.

[0072] Next, the transport device 2 will be described. 1 and 2, the conveying device 2 includes a conveying belt 21, a coating liquid supplying section 8 that supplies a coating liquid 100 of an aqueous pressure-sensitive adhesive composition to a coating surface 210 on the recording medium W side of the conveying belt 21, a blade 9 that levels the coating liquid 100 supplied to the coating surface 210, and a pressure-sensitive adhesive drying section 10 that dries a coating film 105 obtained by passing through the blade 9. The coating liquid supplying section 8, the blade 9, and the pressure-sensitive adhesive drying section 10 may each be incorporated into the conveying device 2, or may be configured to be detachable.

[0073] The coating liquid supply unit 8 has a storage section 81 that stores the coating liquid 100 and a liquid delivery pipe 82 that delivers the coating liquid 100 from the storage section 81 to the vicinity of the coating surface 210, and these perform the supply step shown in FIG. 3 . In this embodiment, when the coating liquid supply unit 8 supplies the coating liquid 100, the conveyor belt 21 is continuously driven to rotate and run. In this case, the running speed of the conveyor belt 21 is kept constant. This makes it possible to continuously change the portion on the coating surface 210 to which the coating liquid 100 is supplied while supplying it. Furthermore, continuous leveling can also be achieved in the leveling step described below.

[0074] The running speed of the conveyor belt 21 in the supplying step and the leveling step described later, i.e., when supplying and leveling the coating liquid 100, is not particularly limited, but is preferably 0.25 m / min to 4 m / min, more preferably 1 m / min. By setting the running speed at such a speed, the coating liquid 100 can be applied quickly and a more uniform and good coating film 105 can be obtained.

[0075] In the present invention, the conveyor belt 21 may be configured to be rotated intermittently. Furthermore, the conveyor belt 21 may be configured to be rotated at any timing and at any speed.

[0076] The storage unit 81 has a storage space for storing the coating liquid 100, and has an outlet 811 for discharging the coating liquid 100 in the storage space. One end 821 of a liquid feed pipe 82 is connected to the outlet 811. The liquid feed pipe 82 transfers the coating liquid 100 to the vicinity of the coating surface 210. The other end 822 of the liquid feed pipe 82 is located above the conveyor belt 21 and upstream of the printing unit 5 (the - side in the y-axis direction). Therefore, the coating liquid 100 discharged from the other end 822 of the liquid feed pipe 82 is dripped onto the coating surface 210 of the conveyor belt 21 at a position offset to the - side in the y-axis direction, i.e., at a position offset to the drive roller 22 side.

[0077] Although not shown, the other end 822 of the liquid supply pipe 82 branches into multiple branches. The branched flow paths are arranged side by side along the x-axis direction, i.e., the width direction of the conveyor belt 21.

[0078] The other end 822 of the liquid supply pipe 82 may be provided with a nozzle, an orifice, or the like. In the present embodiment, the coating liquid 100 stored in the storage section 81 flows by free fall inside the liquid feed pipe 82 from one end 821 to the other end 822, but is not limited to this configuration. For example, a configuration may be adopted in which a pump (not shown) is provided in the middle of the liquid feed pipe 82, and the coating liquid 100 flows inside the liquid feed pipe 82 by driving the pump.

[0079] The supply amount per unit time of the coating liquid 100 supplied from the liquid supply pipe 82 onto the coating surface 210, i.e., the total supply amount of each branch flow path (hereinafter simply referred to as "supply amount"), is not particularly limited, but is preferably 1 L / hour to 4 L / hour, more preferably 2 L / hour. By setting the supply amount to such an amount, the coating liquid 100 can be applied quickly, and the leveling in the leveling step described below can be performed more uniformly and satisfactorily.

[0080] The coating liquid supply unit 8 may be configured to supply the coating liquid 100 continuously or intermittently.

[0081] The blade 9 levels the coating liquid 100 supplied to the coating surface 210 to a uniform thickness. The leveling step shown in Fig. 3 is performed by using the blade 9 to level the coating liquid 100 applied to the coating surface 210. The blade 9 has an elongated shape extending in the width direction of the conveyor belt 21. The blade 9 is fixed in a state in which it is suspended above the conveyor belt 21 by a support part (not shown).

[0082] The blade 9 is provided between the other end 822 of the liquid feed tube 82 and the printing unit 5, that is, downstream of the other end 822 of the liquid feed tube 82 (positive side in the y-axis direction).

[0083] The blade 9 is positioned such that its lower end, i.e., the end on the negative side in the z-axis direction, is spaced a predetermined distance G from the coating surface 210. This distance G is an important factor in determining the thickness of the coating liquid 100, i.e., the coating film 105, after the leveling process, and is particularly important in determining the film thickness of the resulting adhesive layer. The distance G is determined appropriately based on various conditions, such as the viscosity of the coating liquid 100, the supply amount, and the adhesive strength of the desired adhesive layer. When at least one, particularly two or three, of the viscosity, supply amount, and adhesive strength of the coating liquid 100 are within the preferred ranges described above, the distance G is preferably 0.2 mm or more and 10 mm or less, and more preferably 0.5 mm or more and 7 mm or less. This allows the coating film 105 to be formed with a more uniform thickness during the leveling process.

[0084] It is preferable that such distance G is equal along the longitudinal direction of the blade 9, that is, along the x-axis direction, thereby making it possible to make the film thickness of the coating film 105 uniform in the x-axis direction.

[0085] In this way, the blade 9 extends in the width direction of the conveyor belt 21, and is spaced a predetermined distance, i.e., the distance G, from the conveyor belt 21 when leveling the coating liquid 100. This allows the coating liquid 100 to be more uniformly leveled across the entire width of the conveyor belt 21 during the leveling process. In addition, because the blade 9 does not come into contact with the coating surface 210 of the conveyor belt 21, damage to the conveyor belt 21 by the blade 9 can be prevented.

[0086] When leveling the coating liquid 100, the blade 9 may be in contact with the conveyor belt 21 all the time or at appropriate times.

[0087] The coating liquid 100 supplied on the coating surface 210 in the supply process is transported to the +y-axis direction by the movement of the conveyor belt 21, and is leveled as it passes through the gap between the coating surface 210 and the blade 9 by the distance G, making the thickness uniform.

[0088] The blade 9 only needs to be installed above the conveyor belt 21 when the smoothing process is being performed, and may be configured to be removable from the conveyor device 2 when the smoothing process is not being performed.

[0089] The length of the blade 9 in the width direction (x-axis direction) of the conveyor belt 21 is not particularly limited, but is preferably 100 cm or more and 200 cm or less, and more preferably 110 cm or more and 190 cm or less. This allows the length of the blade 9 in the width direction of the conveyor belt 21 to be equal to or longer than the width of the conveyor belt 21, regardless of the model of the printing device 1 or the size of the conveyor belt 21. Therefore, the blade 9 can cover the entire area or effective area of ​​the conveyor belt 21 in the width direction and level the coating liquid 100.

[0090] Conventionally, blades equivalent to blade 9 have been made of metal, which has a higher specific gravity than resin and is therefore heavy. Furthermore, conventional blades are installed at a distance from the conveyor belt so as to extend in the width direction of the conveyor belt. Therefore, when a heavy blade is used, the blade bends under its own weight. This causes the distance G between the blade and the conveyor belt to be inconsistent along the blade's length, making it impossible to evenly distribute the coating liquid to a uniform thickness, resulting in an uneven adhesive layer. Furthermore, in areas where the distance between the blade and the conveyor belt is extremely small, excessive pressure is applied to the coating liquid. If the coating liquid is composed of an aqueous adhesive, the resin present as an emulsion solidifies, causing a problem of alteration in that area and uneven adhesion.

[0091] Therefore, in the present invention, the blade 9 is primarily made of a resin material, and this resin blade 9 is used to level the coating liquid 100. Because the blade 9 is primarily made of a resin material, it is sufficiently strong but lightweight and less likely to bend under its own weight compared to conventional blades made of metal materials. Therefore, the distance G can be maintained constant along the longitudinal direction of the blade 9. This allows the coating liquid 100 to be uniformly leveled across the width of the conveyor belt 21, resulting in a coating film 105 of uniform thickness. Furthermore, because excessive pressure is not applied to the coating liquid 100 due to a partial decrease in the distance G, solidification of the resin in the coating liquid 100 is prevented, and uneven adhesion caused by solidification can be alleviated. Therefore, an adhesive layer with uniform adhesion can be obtained.

[0092] As described above, according to the present invention, an adhesive layer having a uniform thickness and no unevenness in adhesiveness can be formed on the application surface 210 of the conveyor belt 21. Furthermore, by performing printing using the conveyor belt 21 having this adhesive layer, the recording medium W can be transported well and stably, and printing can be performed properly and satisfactorily.

[0093] As described above, the conveying device 2 includes the conveying belt 21 that conveys the recording medium W, and the blade 9 that evens out the aqueous adhesive coating liquid 100 containing water and resin that is supplied to the coating surface 210 of the conveying belt 21 on the recording medium W side, over the coating surface 210, and the blade 9 is mainly made of a resin material. This makes it possible to form an adhesive layer on the coating surface 210 of the conveying belt 21 that has a uniform thickness and is consistent in adhesiveness.

[0094] The printing device 1 includes a conveying device 2 and an inkjet head 51 that performs printing by ejecting ink onto a recording medium W being conveyed by a conveying belt 21. This makes it possible to form an adhesive layer that has a uniform thickness and consistent adhesiveness on the application surface 210 of the conveying belt 21. Furthermore, by performing printing using the conveying belt 21 that has this adhesive layer, the recording medium can be transported stably, and printing can be performed appropriately and satisfactorily.

[0095] The conveying device 2 also includes a coating liquid supply unit 8 that supplies the coating liquid 100 to the coating surface 210. This allows for stable supply of the coating liquid 100. Furthermore, supplying the coating liquid 100 to the coating surface 210 and leveling the coating liquid 100 can be performed continuously.

[0096] The adhesive application method of the present invention includes a supplying step of supplying an aqueous adhesive coating liquid 100 containing water and a resin onto a coating surface 210 on the recording medium W side of a conveyor belt 21 that conveys a recording medium W, and a leveling step of leveling the coating liquid 100 supplied to the coating surface 210 on the coating surface 210 with a blade 9 made mainly of a resin material. This makes it possible to form an adhesive layer on the coating surface 210 of the conveyor belt 21 that has a uniform thickness and is free from uneven adhesion.

[0097] The supplying step may be performed by using another device or by an operator applying the coating liquid 100 using, for example, an applicator. In this case, examples of the applicator include a brush and an application roller.

[0098] Moreover, "mainly made of resin material" means that the content of resin material contained in the blade 9 is 70% by weight or more.

[0099] The resin material contained in the blade 9 is not particularly limited, and examples thereof include hard or soft polyvinyl chloride, polyethylene, polypropylene, polystyrene, polycarbonate, polyamide, acrylic resin, acrylic resin such as polymethyl methacrylate (PMMA), polyester such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polysulfone, polyarylate, fluorine-based resin, etc., and one or more of these may be used in combination.

[0100] Here, "using two or more types in combination" means (1) a material in which resin A is blended with resin B, (2) a material in which resin B is copolymerized with resin A, and (3) a material in which a member made of resin A and a member made of resin B are joined or integrated by, for example, fitting, crimping, bonding, fusing, or fixing with fixing members such as screws or bolts.

[0101] The blade 9 is mainly made of a resin material, but may have a frame material, a core material, a support member, a fixing member, a reinforcing member, etc. inside or outside the blade 9, made of a hard material other than resin, such as a metal material or a ceramic material.

[0102] The specific gravity of the resin material of the blade 9 is preferably 0.5 or more and 2.0 or less, and more preferably 0.6 or more and 1.7 or less. This effectively prevents the blade 9 from bending due to its own weight. Therefore, the above-mentioned effects of using the resin blade 9 can be more significantly obtained.

[0103] The blade 9 smoothes the coating liquid 100 while driving the conveyor belt 21 to run, and the running speed of the conveyor belt 21 when smoothing the coating liquid 100 is substantially the same as the running speed of the conveyor belt 21 during printing. This makes it easy to control the running speed of the conveyor belt 21.

[0104] Here, "substantially the same" is a concept that includes not only cases where there is no difference between the two traveling speeds, but also cases where there is a slight difference between the two traveling speeds, for example, when the average speed difference is within ±5%.

[0105] In the present invention, the running speed of the conveyor belt 21 during printing may be different from the running speed of the conveyor belt 21 during leveling of the coating liquid 100. In other words, the running speed of the conveyor belt 21 may be appropriately changed between when forming the coating film 105 and when printing.

[0106] As shown in FIG. 1, the adhesive drying section 10 is a section where the drying step shown in FIG.

[0107] The adhesive drying unit 10 has a coil 11, which is a heat source (heater). The coil 11 is made of, for example, nichrome wire, and is a heating element that generates heat when power is supplied. The heat generated by the coil 11 can adequately dry the coating film 105 of the coating liquid 100 that has been applied to the coating surface 210 and leveled by the blade 9.

[0108] The position of the adhesive drying unit 10 is not limited to the illustrated configuration. The adhesive drying unit 10 may also be configured to have a fan with an air blowing function. In this case, the heat source such as the coil 11 may be omitted, or the adhesive drying unit 10 may be configured to have both the heat source and the fan.

[0109] In this embodiment, the adhesive drying unit 10 can forcibly or quickly dry the coating film 105, but is not limited thereto, and the adhesive drying unit 10 may be one that dries at room temperature, or one that dries naturally without applying airflow, etc. Furthermore, the conveying device 2 and the printing device 1 may not have the adhesive drying unit 10.

[0110] Furthermore, in the present embodiment, the coating liquid 100 is applied once to the coating surface 210 of the conveyor belt 21, but this is not limiting and the coating may be applied twice or three times. That is, after the supplying step, the leveling step, and the drying step of the coating liquid 100 are performed, these steps may be repeated multiple times. Even in this case, the above-described effects of using the resin blade 9 can be sufficiently obtained.

[0111] Although the conveying device, printing device, and adhesive application method of the present invention have been described above with reference to the illustrated embodiments, the present invention is not limited to these. Furthermore, each part and each step of the conveying device, printing device, and adhesive application method can be replaced with any structure or step that can perform the same function. Furthermore, any structure or step may be added. [Example]

[0112] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0113] In FIG. 4, Table 1 showing the blade materials and physical properties of the water-based adhesives of the examples, reference examples, and comparative examples, and the evaluation results of the examples and comparative examples are provided.

[0114] 2. Resin manufacturing A reactor equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet, and dropping funnel was charged with 114 g of ion-exchanged water and heated to 82°C. Subsequently, a total of 498 g of monomers (measured to have a composition ratio of 36% by weight of ethyl methacrylate, 24% by weight of butyl methacrylate, 4% by weight of butyl acrylate, and 36% by weight of 2-ethylhexyl acrylate), 79 g of ion-exchanged water, and 34 g of Emulgen 123P (surfactant, product name, manufactured by Kao Corporation) were added and mixed with stirring. To the homogenized solution, 249 g of a 2% by weight aqueous solution of ammonium persulfate (polymerization initiator) was added over 1.5 hours at 82°C. After adding all the ingredients listed above, the mixture was kept warm for 1 hour and then cooled. Ion-exchanged water was added and the pH was adjusted to 8-9 with aqueous ammonia. The mixture was filtered through a 150-mesh nylon filter to remove coarse particles, yielding an aqueous dispersion of the resin.

[0115] In Table 1, "PVC" stands for polycarbonate, "PVA" stands for polyvinyl alcohol, "PVdC" stands for polyvinyldenese, "PCTFE" stands for trifluorochloroethylene, and "SUS304" stands for stainless steel. Reference Example 1 is a non-aqueous pressure-sensitive adhesive (organic pressure-sensitive adhesive) with a water content of 0% by mass.

[0116] 3. Preparation of aqueous pressure-sensitive adhesive composition The composition ratios of the aqueous pressure-sensitive adhesive composition and the evaluation results are shown in Table 1. The aqueous dispersion of the resin obtained above, ion-exchanged water, and Emulgen 123P (surfactant, trade name: manufactured by Kao Corporation) were placed in a mixing tank so as to obtain the composition shown in Table 1 (total 100% by mass), and the components were mixed and stirred to obtain an aqueous pressure-sensitive adhesive composition.

[0117] 4. Measurement and evaluation methods 4.1.Viscosity For the aqueous pressure-sensitive adhesive compositions of each example in Table 1, a viscoelasticity tester MCR-300 (manufactured by Pysica) was used at 20°C, and the shear rate was increased from 10 [s-1] to 1000 [s-1], and the value read at a shear rate of 200 was used.

[0118] 4.2. Evaluation of foreign matter on coating film The aqueous adhesive compositions of each Example, Reference Example, and Comparative Example in Table 1 were applied to a conveyor belt using the blade of each Example, Reference Example, and Comparative Example, and the number of white foreign particles (hereinafter referred to as "number of solid particles") per 50 cm square was counted visually and evaluated according to the following criteria. A: The number of solids per 50cm square was less than 10. B: The number of solids per 50cm square was 10 or more but less than 15. C: The number of solids per 50 cm square was 15 or more but less than 30. D: The number of solids per 50 cm square was 30 or more but less than 50. E: The number of solids per 50cm square was 50 or more.

[0119] 4.3. Coating thickness evaluation The aqueous pressure-sensitive adhesive compositions of each Example, Reference Example, and Comparative Example in Table 1 were applied to a conveyor belt using the blade of each Example, Reference Example, and Comparative Example, and the film thickness was measured using a film thickness meter C13027-11 (manufactured by Hamamatsu Photonics KK) The film thickness was measured at three arbitrary points, and the difference in film thickness between each point was calculated and evaluated according to the following criteria. A: The difference in film thickness was less than 15%. B: The difference in film thickness was 15% or more and less than 30%. C: The difference in film thickness was 30% or more and less than 45%. D: The difference in film thickness was 45% or more and less than 60%. E: The film thickness difference was 60% or more.

[0120] 5. Evaluation Results As is clear from the evaluation results in Table 1, when the blade is mainly made of a resin material, the water-based adhesive can be applied to form a uniform coating film. [Explanation of symbols]

[0121] 1...printing device, 2...conveying device, 3...feeding device, 4...winding device, 5...printing section, 6...ink drying section, 8...coating liquid supply section, 9...blade, 10...adhesive drying section, 11...coil, 21...conveyor belt, 22...drive roller, 23...driven roller, 24...tensioner, 25...tensioner, 31...feed roller, 32...tensioner, 41...winding roller, 42...tensioner, 43...tensioner, 44...tensioner, 51...inkjet head, 52...carriage unit, 61...chamber, 62...coil, 81...storage section, 82...liquid supply pipe, 100...coating liquid, 105...coating film, 210...coated surface, 811...discharge port, 821...one end, 822...other end, G...distance, W...recording medium

Claims

1. a conveyor belt for conveying a recording medium; a blade for leveling a coating liquid of an aqueous adhesive containing water and a resin, which is supplied to a coating surface of the conveyor belt on the recording medium side, on the coating surface; The conveying device is characterized in that the blade is mainly made of a resin material.

2. The conveying device according to claim 1 , wherein the blade extends in a width direction of the conveying belt and is spaced a predetermined distance from the conveying belt when leveling the coating liquid.

3. 3. The conveying device according to claim 2, wherein the length of the blade in the width direction of the conveying belt is 100 cm or more and 200 cm or less.

4. 2. The conveyor belt according to claim 1, wherein the specific gravity of the resin material is 0.5 or more and 2.0 or less.

5. 2. The conveying device according to claim 1, wherein the viscosity of the coating liquid at room temperature is 1 cps or more and 500 cps or less.

6. 2. The conveying device according to claim 1, wherein the content of the water in the coating liquid is 30% by weight or more and 80% by weight or less.

7. The conveying device according to claim 1 , further comprising a coating liquid supply unit that supplies the coating liquid to the coating surface.

8. The conveying device according to claim 7; an inkjet head that performs printing by ejecting ink onto the recording medium being transported by the transport belt.

9. 9. The printing device according to claim 8, wherein the blade smoothes the coating liquid while driving the conveyor belt to run, and the running speed of the conveyor belt when smoothing the coating liquid is substantially the same as the running speed of the conveyor belt when printing.

10. a supplying step of supplying a coating liquid of an aqueous adhesive containing water and a resin onto a coating surface of a conveying belt that conveys a recording medium, the coating surface being on the recording medium side; a smoothing step of smoothing the coating liquid supplied to the coating surface over the coating surface with a blade made primarily of a resin material.

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