U.S. patent application number 15/422477 was filed with the patent office on 2017-08-10 for plating method.
This patent application is currently assigned to MIMAKI ENGINEERING CO., LTD.. The applicant listed for this patent is MIMAKI ENGINEERING CO., LTD.. Invention is credited to Masaru OHNISHI.
Application Number | 20170226642 15/422477 |
Document ID | / |
Family ID | 59496794 |
Filed Date | 2017-08-10 |
United States Patent
Application |
20170226642 |
Kind Code |
A1 |
OHNISHI; Masaru |
August 10, 2017 |
PLATING METHOD
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.
Inventors: |
OHNISHI; Masaru; (Nagano,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MIMAKI ENGINEERING CO., LTD. |
NAGANO |
|
JP |
|
|
Assignee: |
MIMAKI ENGINEERING CO.,
LTD.
NAGANO
JP
|
Family ID: |
59496794 |
Appl. No.: |
15/422477 |
Filed: |
February 2, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 18/161 20130101;
C23C 18/1607 20130101; C23C 18/1612 20130101 |
International
Class: |
C23C 18/16 20060101
C23C018/16 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 2016 |
JP |
2016-019992 |
May 25, 2016 |
JP |
2016-104487 |
Claims
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 mPas and less than
or equal to 18 mPas by adding the organic solvent to the
concentrated UV ink having a viscosity greater than or equal to 20
mPas.
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, 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.
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.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] 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
[0002] Field of the Invention
[0003] 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.
[0004] Description of Related Art
[0005] 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).
[0006] 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
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] The UV curable ink may be a solvent UV ink containing an
organic solvent and a concentrated UV ink.
[0013] 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.
[0014] The solvent UV ink may have a viscosity greater than or
equal to 3 mPas and less than or equal to 18 mPas by adding the
organic solvent to the concentrated UV ink having a viscosity
greater than or equal to 20 mPas.
[0015] This aspect may allow the solvent UV ink to have a viscosity
suited to form the plating mask.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] The solvent soluble resin may include at least one of a
butyral resin and a vinyl chloride-vinyl acetate copolymer
resin.
[0021] 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.
[0022] 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.
[0023] By thus suitably adjusting the content ratio of the solvent
soluble resin in the UV curable ink, the plating mask may be
adequately removed.
[0024] The UV curable ink may be a solvent UV ink containing an
organic solvent, a concentrated UV ink, and the solvent soluble
resin.
[0025] 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
[0026] FIG. 1 is a flow chart of a plating method according to a
first embodiment of this disclosure;
[0027] FIG. 2 is a diagram illustrating the plating method
according to the first embodiment;
[0028] FIG. 3 is a schematic side view of ink droplets that have
landed on an object to be plated; and
[0029] FIG. 4 is a diagram illustrating a plating method according
to a second embodiment of this disclosure.
DESCRIPTION OF EMBODIMENTS
[0030] 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
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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 mPas and less than or equal to 18 mPas by adding the organic
solvent to the concentrated UV ink having a viscosity greater than
or equal to 20 mPas. 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.
[0037] As illustrated in FIG. 2, the mask forming step S1 includes
an applying step S1a 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 S1b of curing
the SUV ink through ultraviolet irradiation.
[0038] In the applying step S1a, 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.
[0039] In the applying step S1a, 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 S1a, 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 S1a, 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.
[0040] In the applying step S1a, 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.
[0041] In the curing step S1b, 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.
[0042] 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.
[0043] 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 Sn.sup.2+.Pd.sup.2+. Then, Sn.sup.2+ is stripped to
deposit Pd (palladium).
[0044] 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 S4a of subjecting the object to be
plated 1 to electroless plating. In the electroless plating of the
electroless plating step S4a, 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 S4a may be repeatedly
performed.
[0045] As illustrated in FIG. 2, the plating step may include an
electroplating step S4b in addition to the electroless plating step
S4a. In the electroplating step S4b, 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.
[0046] 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.
[0047] 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.
[0048] 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.
[0049] 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.
[0050] The first embodiment adjusts the viscosity of the solvent UV
ink to stay between 3 mPas and 18 mPas (inclusive), achieving a
viscosity that allows the plating mask 15 to be favorably
formed.
Second Embodiment
[0051] 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.
[0052] In the plating method according to the second embodiment,
the applying step S1a and the curing step S1b, 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 S1c 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.
[0053] 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 S1a and the curing step S1b, thereby
achieving a better working efficiency.
Third Embodiment
[0054] 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.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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
[0062] 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.
[0063] 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.
[0064] 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 mPas and 100,000
mPas. 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.
[0065] 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.
* * * * *