US20170226642A1

US20170226642A1 - Plating method

Info

Publication number: US20170226642A1
Application number: US15/422,477
Authority: US
Inventors: Masaru Ohnishi
Original assignee: Mimaki Engineering Co Ltd
Current assignee: Mimaki Engineering Co Ltd
Priority date: 2016-02-04
Filing date: 2017-02-02
Publication date: 2017-08-10

Abstract

A plating method includes: a mask forming step of discharging a SUV curable ink from an ink jet head in the form of ink droplets and having the ink droplets land on an object to be plated to form a plating mask on the object to be plated; and a plating step of plating the object to be plated subsequent to the mask forming step. In the mask forming step, the ink droplets are discharged so as to have adjacent ones of the ink droplets contact one another.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefits of Japanese Patent Application No. 2016-019992, filed on Feb. 4, 2016 and Japanese Patent Application No. 2016-104487, filed on May 25, 2016. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

Field of the Invention
This disclosure relates to a plating method of plating an object to be plated by forming a plating mask on the object by inkjet printing.
Description of Related Art
In some of the known plating methods employed to subject an object to be plated to metal plating, photoresist is patterned on a substrate with the use of a photomask, and electroless plating is then applied with the use of the patterned photoresist as a mask, to deposit a metal layer (for example, Japanese Unexamined Patent Publication No. 2007-57749).
There are other known methods in which a plating mask is formed at both end parts of a ground electrode layer on a substrate and plating is then applied to form a plated electrode layer on the ground electrode layer (for example, Japanese Unexamined Patent Publication No. 2010-98232). It is described in this reference that the method may apply a resist agent by inkjet printing to form the plating mask.

SUMMARY

The mask formation using the method described in Japanese Unexamined Patent Publication No. 2007-57749, however, gives rise to increased equipment cost, because it requires, for example, an applicator for applying the photoresist to the substrate and an aligner for patterning using the photomask. Further, the mask formation that involves application of the photoresist and exposure using the photomask may be complex and time-consuming, making workability difficult to improve.
Likewise, there is an issue with the mask formation using the method described in Japanese Unexamined Patent Publication No. 2010-98232. In the event that the resist agent is applied to the substrate by inkjet printing and then cured on the substrate, gaps may be present between adjacent droplets of the resist liquid, easily causing fracture in the formed mask, like pinholes. The mask formed then by the cured resist liquid has a large thickness, due to which a plating solution used for plating may be difficult to penetrate into any mask-missing portions, possibly leading to poor resolution of a plating result.
To address the conventional issues, this disclosure provides a plating method that may suppress the occurrence of fracture in a plating mask formed by inkjet printing.
A plating method disclosed herein includes: a mask forming step of discharging a UV curable ink from an ink jet head in the form of ink droplets and having the ink droplets land on an object to be plated to form a plating mask on the object to be plated; and a plating step of plating the object to be plated subsequent to the mask forming step. In the mask forming step, the ink droplets are discharged onto the object to be plated so as to have adjacent ones of the ink droplets contact one another.
According to this aspect, the method thus allowing for contact between ink droplets may connect the ink droplets with no gap therebetween. This may avoid the occurrence of fracture in the plating mask, providing a favorably formed plating mask. The ink droplets, adjacent ones of which are in contact with one another, may become uniform in thickness. Still, parts of the ink droplets with no ink droplet adjacent thereto may be prevented by surface tension from spreading outward. This may suppress the occurrence of smearing in an edge part of the plating mask (boundary between the plating mask and the object to be plated), allowing the plating mask to be finely formed.
The UV curable ink may be a solvent UV ink containing an organic solvent and a concentrated UV ink.
According to this aspect, the solvent UV ink is lowered in viscosity by the organic solvent added thereto. The ink jet head, therefore, may be allowed to smoothly discharge the ink droplets. After the ink droplets lowered in viscosity land on the object to be plated and contact one another, they may favorably spread in the directions of contact with the adjacent ink droplets. Thus, the plating mask formed by the ink droplets may result in a continuous, flat film with no gap therebetween. The ink droplets may spread in the directions of contact with the adjacent ink droplets, whereas parts of the ink droplets with no ink droplet adjacent thereto may be unlikely to spread outward. Afterwards, the organic solvent is heated to volatilize by a heating device so as to thicken the ink droplets, and the ink droplets may be thereby prevented from further spreading. This may suppress the occurrence of smearing in an edge part of the plating mask, allowing the plating mask to be distinctly formed. The plating mask may be reduced in thickness by volatilizing the organic solvent. This may allow a plating solution used for plating to surely penetrate into any plating mask-missing portions. As a result, a plating layer formed on the object to be plated may excel in fineness and distinctness.
The solvent UV ink may have a viscosity greater than or equal to 3 mPa·s and less than or equal to 18 mPa·s by adding the organic solvent to the concentrated UV ink having a viscosity greater than or equal to 20 mPa·s.
This aspect may allow the solvent UV ink to have a viscosity suited to form the plating mask.
In the mask forming step, the object to be plated may be heated by a heating device to volatilize the organic solvent included in the ink droplets landing on the object to be plated, and the ink droplets, after the organic solvent is volatilized, may be irradiated with ultraviolet light emitted from an UV irradiator to cure the ink droplets.
According to this aspect, the organic solvent included in the ink droplets is heated to volatilize by the heating device so as to thicken the ink droplets. This may prevent further spread of the ink droplets and also the occurrence of smearing in an edge part of the plating mask. Then, the ink droplets are irradiated with ultraviolet light, so that the plating mask may be finely formed. An example of the heating device may be a platen heater that heats a target surface of the object to be plated, which is a destination of the ink droplets, from another surface on the opposite side.
The method may further include a mask removing step subsequent to the plating step. The mask removing step is a step of removing the plating mask on the object to be plated using an organic solvent for mask removal. The object to be plated is immersed in a plating solution in the plating step, and the UV curable ink may contain, as an additive, a solvent soluble resin insoluble in the plating solution and soluble in the organic solvent for mask removal.
According to this aspect, since the UV curable ink contains the solvent soluble resin as an additive, the organic solvent used for mask removal may facilitate the removal of the plating mask formed on the object to be plated.
The solvent soluble resin may include at least one of a butyral resin and a vinyl chloride-vinyl acetate copolymer resin.
This aspect using the adhesive vinyl chloride-vinyl acetate copolymer resin and/or butyral resin as the solvent soluble resin may increase adhesion of the plating mask to the object to be plated.
The solvent soluble resin may be included in the UV curable ink in a content greater than or equal to 20% by weight and less than or equal to 70% by weight relative to a total weight of the UV curable ink.
By thus suitably adjusting the content ratio of the solvent soluble resin in the UV curable ink, the plating mask may be adequately removed.
The UV curable ink may be a solvent UV ink containing an organic solvent, a concentrated UV ink, and the solvent soluble resin.
According to this aspect, the solvent UV ink is lowered in viscosity by the organic solvent added thereto. The ink jet head, therefore, may be allowed to smoothly discharge the ink droplets. After the ink droplets lowered in viscosity land on the object to be plated and contact one another, they may favorably spread in the directions of contact with the adjacent ink droplets. Thus, the plating mask formed by the ink droplets may favorably result in a continuous, flat film with no gap therebetween. The ink droplets may spread in the directions of contact with the adjacent ink droplets, whereas parts of the ink droplets with no ink droplet adjacent thereto may be unlikely to spread outward. Afterwards, the organic solvent is heated to volatilize by a heating device so as to thicken the ink droplets, and the ink droplets may be thereby prevented from further spreading. This may suppress the occurrence of smearing in an edge part of the plating mask, allowing the plating mask to be distinctly formed. Favorably, the plating mask may be reduced in thickness by volatilizing the organic solvent. This may allow a plating solution used for plating to surely penetrate into any plating mask-missing portions. As a result, a plating layer formed on the object to be plated may excel in fineness and distinctness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a plating method according to a first embodiment of this disclosure;

FIG. 2 is a diagram illustrating the plating method according to the first embodiment;

FIG. 3 is a schematic side view of ink droplets that have landed on an object to be plated; and

FIG. 4 is a diagram illustrating a plating method according to a second embodiment of this disclosure.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of this disclosure are described in detail referring to the accompanying drawings. This disclosure is not limited by any means by the embodiments hereinafter described. The structural elements described in the embodiments include ones that are easily replaceable with or identical to devices that may be employed by those skilled in the art. The structural elements hereinafter described may be suitably combined, and embodiments plurally provided herein may also be suitably combined.

First Embodiment

In a plating method according to a first embodiment, a plating mask is formed on an object to be plated by inkjet printing, the object to be printed with the plating mask formed thereon is subjected to a plating treatment, and the plating mask is then removed. The plating method is hereinafter described referring to FIGS. 1 to 3.
FIG. 1 is a flow chart of the plating method according to the first embodiment. FIG. 2 is a diagram illustrating the plating method according to the first embodiment. FIG. 3 is a schematic side view of ink droplets that have landed on the object to be plated.
Before proceeding to description of the plating method, an object to be plated 1 is described. The object to be plated 1 may be made of a material such as a resin, metal, or glass. The material may be any kind of material that can be subjected to the plating treatment. The object to be plated 1 may have a three-dimensional shape including a plate-like shape or a curved surface. The shape may be any shape in so far as the plating treatment is applicable to the object 1. In the description given below, the object to be plated 1 is a card made of a resin.
As illustrated in FIG. 1, the plating method according to the first embodiment includes a mask forming step S1, a surface roughening step S2, a catalyst adding step S3, a plating step S4, a mask removing step S5, and a fixing step S6. These steps are performed in the mentioned order. Of these steps, however, at least the mask forming step S1, plating step S4, and mask removing step S5 are required to be performed in the plating method, while the other steps may be omitted if unnecessary.
The mask forming step S1 is a step of discharging an UV curable ink from an ink jet head 10 in the form of ink droplets and having the ink droplets land on the object to be plated 1 to form a plating mask 15 on the object to be plated 1.
The UV curable ink used in the mask forming step according to the first embodiment is now described. The UV curable ink used in the first embodiment is a solvent soluble SUV curable ink (hereinafter, SUV ink) containing an organic solvent soluble in a solvent used in the mask removing step S5 described later. The SUV ink (solvent UV ink) contains the organic solvent and a concentrated UV ink. This is an ink insoluble in an aqueous solution and soluble in the organic solvent. A plating solution used in the plating step S4 described later is soluble in water. Therefore, such an ink is used to prevent the plating mask 15 from being dissolved in the plating step. The concentrated UV ink contains at least a monomer, a colorant, and an initiator. The viscosity of the SUV ink is adjusted to be greater than or equal to 3 mPa·s and less than or equal to 18 mPa·s by adding the organic solvent to the concentrated UV ink having a viscosity greater than or equal to 20 mPa·s. The SUV ink is thickened after the organic solvent is volatilized by heating, and is cured through ultraviolet irradiation during which the initiator is activated and reacted with the monomer.
As illustrated in FIG. 2, the mask forming step S1 includes an applying step S1 a of discharging the SUV ink from the ink jet head 10 in the form of ink droplets and having the ink droplets land on the object to be plated 1, and a curing step S1 b of curing the SUV ink through ultraviolet irradiation.
In the applying step S1 a, the ink jet head 10, while moving in main and sub scanning directions, discharges the ink droplets onto the object to be plated 1 so as to define a predetermined pattern. The front surface of the object to be plated 1 is a target surface to be plated on which the plating mask 15 is formed. The back surface of the object to be plated 1 is provided with a platen heater 12 for heating the object to be plated 1.
In the applying step S1 a, the SUV ink is applied in, for example, four passes in the lateral direction on FIG. 3. In the first pass, ink droplets P1 are discharged, with a given interval therebetween, from the ink jet head 10 onto the object to be plated 1. In the second pass, ink droplets P2 are discharged, with a given interval therebetween as in the first pass, from the ink jet head 10 onto the object to be plated 1. In the applying step S1 a, the ink droplets S2 are discharged from the ink jet head 10 so as to land on the object to be plated 1 in adjacency to and in contact with the ink droplets P1 of the first pass that have landed earlier on the object 1. Similarly, in the third pass, ink droplets P3 are discharged, with a given interval therebetween, from the ink jet head 10 so as to land in adjacency to the ink droplets P2 of the second pass that have landed earlier. In the fourth pass, ink droplets P4 are discharged so as to land between and in adjacency to the ink droplets P1 and P3 of the first and third passes that have landed earlier. In the applying step S1 a, the ink droplets are thus discharged onto the object to be plated 1 to allow for contact among the ink droplets P1 to P4 landing on the object to be plated 1 in adjacency to one another.
In the applying step S1 a, once the ink droplets P1 to P4 lowered in viscosity contact one another, they spread in the directions of contact with the ink droplets P1 to P4 adjacent thereto. Then, the ink droplets P1 to P4 connect to one another with no gap therebetween and become uniform in thickness. As a result, a masking layer 16 formed is a flat, gap-less, continuous film. Of the ink droplets P1 to P4, the ink droplets each on one end side, for example, the leftmost ink droplet P1 and the rightmost ink droplet P4 in FIG. 3 may be prevented by surface tension from spreading outward in their parts with no ink droplet adjacent thereto. Referring to FIG. 3, the leftmost ink droplet P1 may spread in the direction of contact with the adjacent ink droplet P2 on the right side, whereas parts of the ink droplet P1 with no ink droplet adjacent thereto may be unlikely to spread outward. Then, the platen heater 12 volatilizes the organic solvent to thicken the ink droplets, thereby further preventing spread of the ink droplets. After the organic solvent is volatilized, the masking layer 16 becomes thinner.
In the curing step S1 b, the masking layer 16 formed by the ink droplets P1 to P4 that have landed on the surface of the object to be plated 1 is irradiated with ultraviolet light emitted from the ultraviolet irradiator 11 and thereby cured, so that the plating mask 15 is formed.
The surface roughening step S2 roughens the target surface of the object to be plated 1 where the plating mask 15 is not formed. In the surface roughening step S2, the target surface is modified by, for example, etching using an etching solution to form projections and dents thereon. The etching solution is selected from solutions suitable for the object to be plated 1. The surface roughening step S2 may modify the target surface by subjecting the target surface to, for example, sand blasting to generate projections and dents thereon. Thus, the surface roughening step S2 roughens the target surface for better adhesion of plating.
In the catalyst adding step S3, a catalyst is adhered to the roughened target surface. In the first embodiment where the object to be plated 1 is made of a resin, the catalyst is adhered to the target surface for deposition of the plating in the subsequent plating step S4. In the event that the object to be plated 1 is made of a metal, the catalyst adding step S3 may be omitted. In the catalyst adding step S3, the object to be plated 1 is immersed in two solutions in turn, which are a stannous chloride aqueous solution and a palladium chloride aqueous solution, to induce adsorption of Sn²⁺.Pd²⁺. Then, Sn²⁺ is stripped to deposit Pd (palladium).
The plating step S4 subjects the catalyst-adhered object to be plated 1 to the plating treatment. The plating step S4 includes an electroless plating step S4 a of subjecting the object to be plated 1 to electroless plating. In the electroless plating of the electroless plating step S4 a, the object to be plated 1 is immersed, for electroless plating, over a certain period of time in an electroless plating solution which has a predetermined temperature and which is stored in an electroless plating bath 21. The electroless plating solution may include diamond or titanium oxide particles. The electroless plating step S4 a may be repeatedly performed.
As illustrated in FIG. 2, the plating step may include an electroplating step S4 b in addition to the electroless plating step S4 a. In the electroplating step S4 b, the electroless-plated target surface of the object to be plated 1 is set to an anode and immersed in a plating solution stored in an electroplating bath 22.
The mask removing step S5 removes the plating mask 15 formed on the object to be plated 1 after the plating treatment is applied thereto. In the mask removing step S5 using the solvent soluble ink to form the plating mask 15, the object to be plated 1 is, for example, immersed in an organic solvent such as alcohol (organic solvent for plating mask removal), so that the plating mask 15 is dissolved away. Specifically, the mask removing step S5 immerses and warms the object to be plated 1 in propyl alcohol heated to a predetermined temperature.
In the fixing step S6, the object to be plated 1, from which the plating mask 15 has been removed, is placed and heated in a heating chamber 25 to fix the plating to the object 1. In the first embodiment, the fixing step S6 is carried out to adequately fix the plating on the object to be plated 1. The fixing step S6, however, may be omitted in the event that the plating has been fixed well to the object to be plated 1 in the plating step S4.
According to the first embodiment, the ink droplets P1 to P4 are discharged to contact one another and thereby connect to one another with no gap therebetween. This may avoid the occurrence of fracture in the plating mask 15, providing the plating mask 15 favorably formed. The ink droplets P1 to P4, adjacent ones of which are in contact with one another, may become uniform in thickness. Still, parts of the ink droplets P1 to P4 with no ink droplet adjacent thereto may be prevented by surface tension from spreading outward. This may suppress the occurrence of smearing in an edge part of the plating mask 15 (boundary between the plating mask 15 and the object to be plated 1), allowing the plating mask 15 to be finely formed.
The first embodiment uses the SUV ink lowered in viscosity by the organic solvent added thereto, allowing the ink jet head 10 to smoothly discharge the ink droplets P1 to P4. After the ink droplets P1 to P4 lowered in viscosity land on the object to be plated 1 and contact one another, they may spread in the directions of contact with the ink droplets P1 to P4 adjacent thereto. On the other hand, parts of the ink droplets P1 to P4 with no ink droplet adjacent thereto may be unlikely to spread outward. The organic solvent is heated to volatilize by the platen heater 12 so as to thicken the ink droplets P1 to P4, and the ink droplets P1 to P4 may be thereby prevented from further spreading. This may suppress the occurrence of smearing in an edge part of the plating mask 15, allowing the plating mask 15 to be distinctly formed. The plating mask 15 may be reduced in thickness by volatilizing the organic solvent. This may allow the plating solution to surely penetrate into any portions where the plating mask 15 is not formed. As a result, the plating formed on the object to be plated 1 may excel in fineness and distinctness.
The first embodiment adjusts the viscosity of the solvent UV ink to stay between 3 mPa·s and 18 mPa·s (inclusive), achieving a viscosity that allows the plating mask 15 to be favorably formed.

Second Embodiment

A plating method according to a second embodiment is hereinafter described referring to FIG. 4. The second embodiment focuses on structural elements that differ from the first embodiment to avoid redundant description, while simply referring to the ones similar to the first embodiment using the same reference signs. FIG. 4 is a diagram illustrating the plating method according to the second embodiment.
In the plating method according to the second embodiment, the applying step S1 a and the curing step S1 b, which are included in the mask forming step S1 according to the first embodiment, are carried out at the same time. The second embodiment uses the ink jet head 10 and the ultraviolet irradiator 11 that are integrally formed. In a mask forming step S1 c according to this embodiment, the ink droplets P1 to P4 discharged from the ink jet head 10 that have landed on the object to be plated 1 are irradiated with ultraviolet light emitted from the ultraviolet irradiator 11. The ultraviolet irradiator 11 is disposed on the rear side relative to the ink jet head 10 in a direction where the ink jet head 10 moves. The ink jet head 10 and the ultraviolet irradiator 11 are spaced apart at a given interval that allows the ultraviolet irradiator 11 to emit ultraviolet light after adjacent ones of the ink droplets P1 to P4 contact and connect to one another. The emission of ultraviolet light may be performed plural times. For example, immediately after being discharged, the ink droplets P1 to P4 may be precured by ultraviolet light of luminous intensity less than or equal to 50% of luminous intensity for full cure. The ink droplets P1 to P4 are then fully cured by ultraviolet light after the plating mask 15 is patterned by the ink jet head 10.
As in the first embodiment, the second embodiment allows the ink droplets P1 to P4 to contact and connect to one another with no gap therebetween. This may avoid the occurrence of fracture in the plating mask 15, providing the plating mask 15 favorably formed. The plating method according to this embodiment concurrently performs the applying step S1 a and the curing step S1 b, thereby achieving a better working efficiency.

Third Embodiment

A plating method according to a third embodiment is hereinafter described. The third embodiment focuses on structural elements that differ from the first and second embodiments to avoid redundant description, while simply referring to the ones similar to the first and second embodiments using the same reference signs.
In the plating method according to the third embodiment, the UV curable ink used in the mask forming step S1 contains a solvent soluble resin as an additive. The UV curable ink specifically contains a concentrated UV ink and a solvent soluble resin. As in the first embodiment, the concentrated UV ink contains at least a monomer, a colorant, and an initiator.
The solvent soluble resin is insoluble in the plating solution used in the plating step S4 but is soluble in the organic solvent used in the mask removing step S5 such as propyl alcohol. Specifically, the solvent soluble resin includes at least one of a butyral resin and a vinyl chloride-vinyl acetate copolymer resin. The vinyl chloride-vinyl acetate copolymer resin and the butyral resin both have adhesiveness. Such a material(s) may increase adhesion of the plating mask 15 formed on the object to be plated 1 in the mask forming step S1. The solvent soluble resin is included in the UV curable ink in a content greater than or equal to 20% by weight and less than or equal to 70% by weight relative to a total weight of the UV curable ink.
Depending on the material of the object to be plated 1, the solvent soluble resin may be suitably selected from the vinyl chloride-vinyl acetate copolymer resin and the butyral resin. A butyral resin readily soluble in an organic solvent, such as ethanol, may be preferably used.
The plating method according to the third embodiment using the UV curable ink is similar to the plating method according to the first embodiment. In the third embodiment, the UV curable ink used in the first embodiment is replaced with the UV curable ink described above. Otherwise, the plating methods according to the first and third embodiments include and perform the same processing steps. In the mask forming step S1, the UV curable ink of the third embodiment is used to increase adhesion of the plating mask 15 to the object to be plated 1 as compared with the first embodiment. The mask removing step S5 using the UV curable ink of the third embodiment enhances solubility of the plating mask 15 in the organic solvent.
Since the UV curable ink contains the solvent soluble resin as an additive in the third embodiment, the organic solvent used in the mask removing step S5 may facilitate the removal of the plating mask 15 formed on the object to be plated 1.
The vinyl chloride-vinyl acetate copolymer resin and the butyral resin both have adhesiveness. The third embodiment using both of such materials as the solvent soluble resin may increase adhesion of the plating mask 15 to the object to be plated 1.
The third embodiment may suitably adjust the content ratio of the solvent soluble resin in the UV curable ink, thereby allowing the plating mask 15 to be adequately removed.

Fourth Embodiment

A plating method according to a fourth embodiment is hereinafter described. The fourth embodiment focuses on structural elements that differ from the first to third embodiments to avoid redundant description, while simply referring to the ones similar to the first to third embodiments using the same reference signs.
The plating method according to the fourth embodiment uses a solvent soluble SUV curable ink (hereinafter, SUV ink). This ink is prepared by adding an organic solvent to the UV curable ink of the third embodiment. The SUV ink (solvent UV ink) contains the solvent soluble resin, organic solvent, and concentrated UV ink. This ink may be rephrased as the SUV ink of the first embodiment further containing the solvent soluble resin. The SUV ink of the fourth embodiment contains the same organic solvent and concentrated UV ink as in the first embodiment, and contains the same solvent soluble resin as in the third embodiment.
The SUV ink according to the fourth embodiment is prepared by adding the solvent soluble resin and the organic solvent to the concentrated UV ink having a viscosity between 10 mPa·s and 100,000 mPa·s. Relative to a total weight of the SUV ink, the solvent soluble resin is included in the SUV ink in a content greater than or equal to 20% by weight and less than or equal to 70% by weight, and the organic solvent is included in the SUV ink in a content greater than or equal to 30% by weight and less than or equal to 80% by weight. The SUV ink is prepared, so that the summed content ratios of the concentrated UV ink, solvent soluble resin, and organic solvent amount to 100% by weight. An example of the organic solvent is Cellosolve acetate.
Similarly to the first embodiment, the fourth embodiment uses the SUV ink lowered in viscosity by the organic solvent added thereto, allowing the ink jet head 10 to smoothly discharge the ink droplets P1 to P4. As a result, the plating formed on the object to be plated 1 may excel in fineness and distinctness.

Claims

What is claimed is:

1. A plating method, comprising:

a mask forming step of discharging a UV curable ink from an inkjet head in the form of ink droplets and having the ink droplets land on an object to be plated to form a plating mask on the object to be plated; and

a plating step of plating the object to be plated subsequent to the mask forming step,

the mask forming step discharging the ink droplets so as to have adjacent ones of the ink droplets contact one another.

2. The plating method according to claim 1, wherein the UV curable ink is a solvent UV ink comprising an organic solvent and a concentrated UV ink.

3. The plating method according to claim 2, wherein the solvent UV ink has a viscosity greater than or equal to 3 mPa·s and less than or equal to 18 mPa·s by adding the organic solvent to the concentrated UV ink having a viscosity greater than or equal to 20 mPa·s.

4. The plating method according to claim 2, wherein, in the mask forming step,

the object to be plated is heated by a heating device to volatilize the organic solvent included in the ink droplets landing on the object to be plated, and

the ink droplets, after the organic solvent is volatilized, are irradiated with ultraviolet light emitted from an UV irradiator to cure the ink droplets.

5. The plating method according to claim 3, wherein, in the mask forming step,

6. The plating method according to claim 1, further comprising a mask removing step subsequent to the plating step, the mask removing step being a step of removing the plating mask on the object to be plated using an organic solvent for mask removal, wherein

the object to be plated is immersed in a plating solution in the plating step, and

the UV curable ink comprises, as an additive, a solvent soluble resin insoluble in the plating solution and soluble in the organic solvent for mask removal.

7. The plating method according to claim 6, wherein the solvent soluble resin comprises at least one of a butyral resin and a vinyl chloride-vinyl acetate copolymer resin.

8. The plating method according to claim 6, wherein the solvent soluble resin is included in the UV curable ink in a content greater than or equal to 20% by weight and less than or equal to 70% by weight relative to a total weight of the UV curable ink.

9. The plating method according to claim 7, wherein the solvent soluble resin is included in the UV curable ink in a content greater than or equal to 20% by weight and less than or equal to 70% by weight relative to a total weight of the UV curable ink.

10. The plating method according to claim 6, wherein the UV curable ink is a solvent UV ink comprising an organic solvent, a concentrated UV ink, and the solvent soluble resin.

11. The plating method according to claim 7, wherein the UV curable ink is a solvent UV ink comprising an organic solvent, a concentrated UV ink, and the solvent soluble resin.

12. The plating method according to claim 8, wherein the UV curable ink is a solvent UV ink comprising an organic solvent, a concentrated UV ink, and the solvent soluble resin.