JP2014205351A - Printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve printing characteristics by devising the temperature of a recording medium at the time of printing and the surface treatment of the recording medium.SOLUTION: A printing method includes the steps of: raising the temperature of a recording medium to 30°C or higher; discharging an ink composition including a polymerizable compound and a photoinitiator onto the recording medium whose temperature has been raised to 30°C or higher; and polymerizing the polymerizable compound by irradiating light to the discharged ink composition. Preferably, a recording medium subjected to surface treatment using a polyester resin is used as the recording medium.

Description

The present invention relates to a printing method, and more particularly to a printing method in which the temperature of a recording medium at the time of printing and the surface treatment of the recording medium are devised in order to improve adhesion.

In recent years, ultraviolet curable inks have been used to form prints having high water resistance, solvent resistance, scratch resistance, and the like on the surface of print media. This ultraviolet curable ink has a polymerizable compound and a photopolymerization initiator, and printing is performed by discharging the ink onto a print medium, polymerizing the ink composition by ultraviolet irradiation, and solidifying. At this time, since the ink is discharged onto a non-absorbing medium, that is, a printing medium that does not absorb ink, the adhesion between the printing medium and the ink has a great influence on the printing characteristics.

For example, Patent Document 1 below discloses a technique for improving thermal efficiency in an inkjet recording apparatus that performs recording by heating a recording medium. Patent Document 2 below discloses a technique for heating a recording medium in order to efficiently cure an electromagnetic radiation curable liquid composition. Patent Document 3 below discloses a technique for heating ink ejected on a recording medium with a microwave heating device.

JP 2005-125513 A Japanese Patent Laid-Open No. 2006-62346 JP 2007-8351 A

The present inventor has been conducting research and development on improving the printing characteristics of ultraviolet curable ink. As a result of intensive studies, the printing characteristics, particularly the adhesion, have been improved by the temperature of the printing medium and the printing medium (recording medium). It has been reached that the surface state is closely related.

Therefore, a specific aspect of the present invention aims to improve printing characteristics by devising the temperature of the recording medium during printing and the surface treatment of the recording medium.

The printing method according to the present invention includes an ink composition having a step of heating a recording medium to 30 ° C. or higher, and a polymerizable compound and a photopolymerization initiator on the recording medium heated to 30 ° C. or higher. And a step of polymerizing the polymerizable compound by irradiating the discharged ink composition with light.

Preferably, the recording medium is a recording medium surface-treated with a polyester resin.

Preferably, the polyester resin is a dehydration condensate of a polyhydric alcohol and a dicarboxylic acid, and the dicarboxylic acid is isophthalic acid or glutaric acid.

Thus, by raising the temperature of the recording medium to 30 ° C. or higher, the adhesion between the recording medium and the ink is improved, and the printing characteristics are improved. In addition, the use of a polyester resin as the recording medium further improves the adhesion between the recording medium and the ink.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
[Ink composition]
The ink composition according to this embodiment has at least 1) a polymerizable compound and 2) a photopolymerization initiator.
1) Polymerizable compound The polymerizable compound used in the ink composition of the present embodiment is not particularly limited as long as it is a compound that polymerizes and solidifies upon irradiation with light such as ultraviolet rays by the action of a photopolymerization initiator described later. But,
Various monomers and oligomers having a monofunctional group, a bifunctional group, and a polyfunctional group having three or more functional groups can be used.

Examples of the monomer include unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid and maleic acid, salts or esters thereof, urethane,
Amides and their anhydrides, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes. Examples of the oligomer include oligomers formed from the above monomers such as linear acrylic oligomers, epoxy (meth) acrylates, aliphatic urethane (meth) acrylates, aromatic urethane (meth) acrylates, and polyesters (meth). An acrylate is mentioned.

Among those listed above, esters of (meth) acrylic acid, that is, (meth) acrylates are preferred.

Among the (meth) acrylates, monofunctional (meth) acrylates include, for example, isoamyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, iso Myristyl (meth) acrylate, isostearyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol ( (Meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate , Tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, lactone-modifiable Examples include flexible (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and isobornyl (meth) acrylate.

Among the (meth) acrylates, examples of the bifunctional (meth) acrylate include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and tripropylene glycol di ( (Meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4
-Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (
(Meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, EO (ethylene oxide) adduct di (meth) acrylate of bisphenol A, PO (propylene oxide) adduct di (meth) acrylate of bisphenol A, hydroxypivalic acid Examples include neopentyl glycol di (meth) acrylate and polytetramethylene glycol di (meth) acrylate.

Among the (meth) acrylates, the trifunctional or higher polyfunctional (meth) acrylates include, for example, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth) acrylate. ,
Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin propoxytri (meth) acrylate, cowprolactone-modified trimethylolpropane tri (meth) acrylate, pentaerythritol ethoxy Tetra (meth) acrylate,
And caprolactam-modified dipentaerythritol hexa (meth) acrylate.

Moreover, an N-vinyl compound may be included as another monofunctional monomer or polyfunctional monomer. Examples of the N-vinyl compound include N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam, and derivatives thereof.

Among these, a monofunctional (meth) acrylate is included as a polymerizable compound from the viewpoint of easy injection stability at the time of ink jet recording because the coating film has a high elongation at curing and low viscosity. It is preferable. Further, from the viewpoint of increasing the hardness of the coating film, it is more preferable to use a monofunctional (meth) acrylate and a bifunctional (meth) acrylate in combination. Said polymeric compound may be used individually by 1 type, and may use 2 or more types together.

Furthermore, the monofunctional (meth) acrylate preferably has one or more skeletons selected from the group consisting of an aromatic ring skeleton, a saturated alicyclic skeleton, and an unsaturated alicyclic skeleton. When the polymerizable compound is a monofunctional (meth) acrylate having the skeleton, the viscosity of the ink composition can be reduced, and the epoxy group-containing polymer can be effectively dissolved in the ink composition. it can.

As a monofunctional (meth) acrylate having an aromatic ring skeleton, for example, phenoxyethyl (
And (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate. Examples of the monofunctional (meth) acrylate having a saturated alicyclic skeleton include isobornyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. Examples of the monofunctional (meth) acrylate having an unsaturated alicyclic skeleton include dicyclopentenyloxyethyl (meth) acrylate.
2) Photopolymerization initiator The polymerization initiator contained in the ink composition of the present embodiment generates active species such as radicals and cations by the energy of light such as ultraviolet rays, and initiates polymerization of the polymerizable compound. If it is, there is no restriction | limiting, However, A radical polymerization initiator and a cationic polymerization initiator can be used, It is preferable to use a radical polymerization initiator especially.

Examples of the radical polymerization initiator include aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, and azinium compounds. , Metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

Specific examples of the radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, Carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) 2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Sandone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenyl Phosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone and bis- (2,6-dimethoxybenzoyl)
Examples include -2,4,4-trimethylpentylphosphine oxide.

Examples of commercially available radical polymerization initiators include IRGACURE 651 (2,2-
Dimethoxy-1,2-diphenylethane-1-one), IRGACURE 184 (1-
Hydroxy-cyclohexyl-phenyl-ketone), DAROCUR 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 29
59 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one), IRGACURE 127 (2-hydroxy-1- {4
-[4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl] -2-
Methyl-propan-1-one}, IRGACURE 907 (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one), IRGACURE 36
9 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), DAR
OCUR TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 784 (bis (η5-2,4 -Cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1)
-Yl) -phenyl) titanium), IRGACURE OXE 01 (1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), IR
GACURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime)), IRGA
CURE 754 (a mixture of oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester) (above, Ciba Japan KK)), DETX-S
(2,4-diethylthioxanthone) (manufactured by Nippon Kayaku Co., Ltd.),
Examples include Lucirin TPO, LR8883, LR8970 (above, manufactured by BASF) and Ubekrill P36 (manufactured by UCB).

The said photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

Although it is possible to omit the addition of a photopolymerization initiator by using a photopolymerizable compound as the polymerizable compound described above, it is easier to start polymerization by using a photopolymerization initiator. It can be adjusted and is preferred.
3) Coloring material The ink composition of the present embodiment may further include a coloring material. The color material is at least one of a pigment and a dye.
(Pigment)
In this embodiment, the light resistance of the ink composition can be improved by using a pigment as the color material. As the pigment, both inorganic pigments and organic pigments can be used.

As the inorganic pigment, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, iron oxide, and titanium oxide can be used.

Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Polycyclic pigments, dye chelates (for example, basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daytime A photofluorescent pigment is mentioned. The said pigment may be used individually by 1 type, and may use 2 or more types together.

Further, any pigment not described in the color index can be used as long as it is insoluble in water.
(dye)
In the present embodiment, a dye can be used as the color material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 14
2, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I.
Food Black 1, 2, C.I. I. Direct yellow 1, 12, 24, 33, 50, 55
58, 86, 132, 142, 144, 173, C.I. I. Direct red 1, 4, 9
, 80, 81, 225, 227, C.I. I. Direct blue 1, 2, 15, 71, 86,
87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51,
71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55
79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.
4) Conditioner (other ingredients)
The ink composition of this embodiment may contain components other than the components listed above. For example,
A surfactant may be included.

As the surfactant, for example, polyester-modified silicone or polyether-modified silicone can be used as a silicone-based surfactant, and it is particularly preferable to use polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane.
Specific examples include BYK-347, BYK-348, BYK-UV3500, 3510,
3530, 3570 (Bic Chemie Japan Co., Ltd.).

Further, a polymerization inhibitor may be added. By adding a polymerization inhibitor, the storage stability of the ink composition is improved. As the polymerization inhibitor, for example, hindered amine polymerization inhibitor IRGASTAB UV10 (Ciba Specialty Chemicals) and the like can be used.

Further, a dispersant, a polymerization accelerator, a slip agent, a penetration accelerator and a wetting agent (humectant), and other additives may be included. Examples of other additives include fixing agents, antifungal agents, preservatives, antioxidants, ultraviolet absorbers, chelating agents, pH adjusters, and thickeners.
[Print media]
As the print medium (recording medium), a print medium obtained by performing a predetermined surface treatment on the base material is used. The base material is not particularly limited as long as it is a non-absorbing medium. For example, a resin material such as polyethylene terephthalate (PET), polypropylene, or polyethylene can be used.

The substrate is subjected to a surface treatment using a polyester resin, and a treatment layer (resin layer, coat layer) is provided on the substrate surface. If the polyester resin is coated (fixed) on the substrate surface,
Although there is no restriction | limiting in the processing method, For example, after dissolving polyester-type resin in a solvent and apply | coating on a base material, you may form a polyester-type resin layer on a base material by making it dry. The polyester-based resin refers to a polymer having —CO—O— in the molecular main chain, and various configurations are conceivable. As an example, a dehydration condensate of glycol and dicarboxylic acid can be cited (
[See Chemical Formula 1]. Examples of the glycol include diethylene glycol, and examples of the dicarboxylic acid include those shown in Table 3 below. Moreover, you may use not only glycol (dihydric alcohol) but polyhydric alcohol more than bivalence.

［化１］において、Ｒ１、Ｒ２は、（ＣＨ₂）ｎやベンゼン環などである。
［印刷方法］
上記印刷メディアをヒーター上に配置し、印刷メディア上部から前述のインク組成物を
インクジェット法により吐出し、吐出液滴に対し紫外線（光）照射を行い、インク（各種
重合性化合物）を重合させ、硬化させることにより印刷を行う。ヒーター温度は、３０℃
以上とし、印刷メディアを３０℃以上に昇温する。

In [Chemical Formula 1], R 1 and R 2 are (CH ₂ ) n, a benzene ring, and the like.
[Printing method]
The above-mentioned print medium is placed on a heater, the above ink composition is ejected from the upper part of the print medium by an inkjet method, ultraviolet (light) irradiation is performed on the ejected droplets, and the ink (various polymerizable compounds) is polymerized. Printing is performed by curing. Heater temperature is 30 ° C
The printing medium is heated to 30 ° C. or higher.

As described above, in this embodiment, by raising the temperature of the print medium to 30 ° C. or more, the adhesion between the recording medium and the ink can be improved, and the printing characteristics can be improved. In addition, by using a polyester-based resin as the printing medium, the adhesion between the recording medium and the ink can be further improved.

Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
[Ink composition]
As shown in Table 1, 40% by mass of N-vinylcaprolactam as a polymerizable compound, 4% by mass of IRGACURE 819 and IRGACURE 369 as photopolymerization initiators, and 0.1% of BYK UV3500 as various regulators. Mass%, IRGAST
AB UV10 is added in an amount of 0.2% by mass, pigment blue 15: 3 is added as a coloring material in a proportion of 3% by mass, and tripropylene glycol diacrylate is used as a polymerizable compound.
Ink <1> was adjusted so that the total amount was 100% by mass. In this case, tripropylene glycol diacrylate is 48.7% by mass.

［印刷メディア］

[Print media]

表２に示すように、ポリエステル系樹脂を用いて表面処理された印刷メディアとして、
ジカルボン酸成分としてイソフタル酸を用いたポリエステル系樹脂で表面処理された印刷
メディア<1>、ジカルボン酸成分としてグルタル酸を用いたポリエステル系樹脂で表面処
理された印刷メディア<2>、ジカルボン酸成分としてアジピン酸を用いたポリエステル系
樹脂で表面処理された印刷メディア<3>およびアミド系樹脂で表面処理された印刷メディ
ア<4>を準備する。なお、表３に、イソフタル酸、グルタル酸およびアジピン酸の構造式
を示す。

As shown in Table 2, as a print medium surface-treated with a polyester resin,
Printing media surface treated with polyester resin using isophthalic acid as the dicarboxylic acid component <1>, printing media surface treated with polyester resin using glutaric acid as the dicarboxylic acid component <2>, as dicarboxylic acid component Print media <3> surface-treated with a polyester resin using adipic acid and print media <4> surface-treated with an amide resin are prepared. Table 3 shows the structural formulas of isophthalic acid, glutaric acid and adipic acid.

各印刷メディア<1>〜<4>としては、ポリエチレンテレフタレート基材に、各樹脂で表面
処理された印刷メディアを用いた。係る印刷メディアは、例えば、樹脂溶液をバーコータ
で塗布、乾燥して作成することができるが、ここでは、本発明者によるフーリエ変換赤外
分光光度計(ＦＴＩＲ)による解析の結果、各樹脂が検出されたメディアを採用した。

As each print media <1> to <4>, a print media surface-treated with each resin on a polyethylene terephthalate substrate was used. Such print media can be prepared, for example, by applying a resin solution with a bar coater and drying, but here, as a result of analysis by a Fourier transform infrared spectrophotometer (FTIR) by the present inventor, each resin is detected. Adopted media.

Place the above print media <1> to <4> on the heater, eject ink <1> from the top of the print media by inkjet method, irradiate the ejected droplets with ultraviolet (light), ink (various polymerization properties) Printing was carried out by polymerizing and curing the compound. Three printing media were prepared, and printing was performed at heater temperatures of 20 ° C., 30 ° C., and 40 ° C.

The adhesiveness to the printed matter was evaluated. For adhesion, JIS K56
The measurement was performed by a test according to the 00-5-6 test. Specifically, crosscutting was performed to divide a plurality of squares on the print medium, and after printing on each square, evaluation was made based on the following levels A to D from the presence or absence (amount) of peeling with a cellophane tape.
A: Adhesion level 0 to 1
B: Adhesion level 2-3
C: Adhesion level 4-5,
It shows that adhesiveness decreases in order from A, and the adhesiveness level is JIS K5600-5-6.
According to the classification of

  The evaluation results are shown in Table 4.

表４に示すように、実施例１：３０℃のメディア<1>を用いた印字、実施例２：４０℃
のメディア<1>を用いた印字、実施例３：３０℃のメディア<2>を用いた印字、実施例４：
４０℃のメディア<2>を用いた印字、実施例５：３０℃のメディア<3>を用いた印字、およ
び実施例６：４０℃のメディア<3>を用いた印字の場合には、比較例４：２０℃のメディ
ア<4>を用いた印字、比較例５：３０℃のメディア<4>を用いた印字および比較例６：４０
℃のメディア<4>を用いた印字の場合と比較し、インクの良好な密着性が確認できた。

As shown in Table 4, Example 1: Printing using media <1> at 30 ° C, Example 2: 40 ° C
Printing using a medium <1>, Example 3: printing using a medium <2> at 30 ° C., Example 4:
Comparison using 40 ° C media <2>, Example 5: Printing using 30 ° C media <3>, and Example 6: Printing using 40 ° C media <3> Example 4: Printing using media <4> at 20 ° C, Comparative Example 5: Printing using media <4> at 30 ° C and Comparative Example 6:40
Compared to printing using media <4> at ℃, good ink adhesion was confirmed.

In particular, when media <1> and <2> that were surface-treated with a polyester resin using isophthalic acid and glutaric acid as dicarboxylic acid components were used (Examples 1 to 4),
Particularly good results were obtained.

However, even when the above media <1> to <3> are used, Comparative Example 1: Printing using 20 ° C. media <1>, Comparative Example 2: Using 20 ° C. media <2> Printing and Comparative Example 3:
As is apparent from the printing using the media <3> at 20 ° C., the adhesion decreased when the media temperature was as low as 20 ° C.

Further, according to the study of the present inventors, even when the ink having the composition shown in Table 5 was used, the tendency shown in Table 4 was not changed. The unit of the numerical values shown in Table 5 is [% by mass].

表５は、上述のインク組成物(表１）であるシアン（Cyan）インクの他、ブラック（Bla
ck)インク、マゼンタ（Magenta)インクおよびイエロー（Yellow）インクの３種を示した
ものであり、その組成を以下に説明する。

Table 5 shows cyan (Byan) ink, which is the ink composition (Table 1), and black (Bla).
ck) ink, magenta ink, and yellow ink are shown, and their compositions will be described below.

In the black ink, 40% by mass of N-vinylcaprolactam is used as a polymerizable compound, and IRGACURE 819 and IRGACURE are used as photopolymerization initiators.
369, 4% by weight each, various adjusting agents, BYK UV3500 0.1% by weight, IRGASTAB UV10 0.2% by weight, and pigment black 7 3
The ink <1> was adjusted so that the total amount was 100 mass% using tripropylene glycol diacrylate as a polymerizable compound. In this case, tripropylene glycol diacrylate is 48.7% by mass.

In Magenta ink, 3% by mass of Pigment Red 122 is used as a coloring material.
The composition is the same as that of the black ink except that it is added in the ratio of.

The yellow ink also has the same composition as the black ink except that pigment yellow 180 is added as a coloring material at a ratio of 3% by mass.

Black ink, magenta ink or yellow (Yellow) of the above composition
) The tendency shown in Table 4 did not change even when ink was used.

As described above, it has been found that the ink adhesion is improved by printing the above-mentioned print media <1> to <3> in a state where the temperature is raised to 30 ° C. or higher. In particular, it is preferable to use a printing medium surface-treated with a polyester resin, and it is particularly preferable to use a printing medium surface-treated with a polyester resin using isophthalic acid or glutaric acid as a dicarboxylic acid component. Note that the temperature of the print medium is preferably 60 ° C. or less from the viewpoint of preventing deformation of the print medium.

Claims (3)

Heating the recording medium to 30 ° C. or higher;
A step of discharging an ink composition having a polymerizable compound and a photopolymerization initiator on the recording medium heated to 30 ° C. or higher;
A step of polymerizing the polymerizable compound by irradiating the discharged ink composition with light. The recording medium is a recording medium surface-treated with a polyester resin.
The printing method described. The polyester resin is a dehydration condensate of a polyhydric alcohol and a dicarboxylic acid,
The printing method according to claim 2, wherein the dicarboxylic acid is isophthalic acid or glutaric acid.