U.S. patent application number 17/271191 was filed with the patent office on 2021-07-01 for outer case for hot water unit, and hot water unit provided therewith.
This patent application is currently assigned to NORITZ CORPORATION. The applicant listed for this patent is NORITZ CORPORATION. Invention is credited to Nobuhiro Fukui.
Application Number | 20210199342 17/271191 |
Document ID | / |
Family ID | 1000005504198 |
Filed Date | 2021-07-01 |
United States Patent
Application |
20210199342 |
Kind Code |
A1 |
Fukui; Nobuhiro |
July 1, 2021 |
OUTER CASE FOR HOT WATER UNIT, AND HOT WATER UNIT PROVIDED
THEREWITH
Abstract
This outer case (C) for a hot water unit, configured using a
metal plate (30a), is provided with a paint layer (30b) which is
provided to cover the front surface and/or back surface of the
metal plate (30a), an inkjet printing layer (4) which is laminated
on the paint layer (30b) and which shows text, symbols, figures
and/or patterns, and a clear layer (5) which covers the inkjet
printing layer (4). By means of this configuration, the outer case
(C) can be produced with high productivity and at a low cost, and
with excellent design and resistance properties.
Inventors: |
Fukui; Nobuhiro; (HYOGO,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NORITZ CORPORATION |
HYOGO |
|
JP |
|
|
Assignee: |
NORITZ CORPORATION
HYOGO
JP
|
Family ID: |
1000005504198 |
Appl. No.: |
17/271191 |
Filed: |
August 23, 2019 |
PCT Filed: |
August 23, 2019 |
PCT NO: |
PCT/JP2019/032987 |
371 Date: |
February 24, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24H 9/02 20130101; F24H
9/2007 20130101 |
International
Class: |
F24H 9/02 20060101
F24H009/02; F24H 9/20 20060101 F24H009/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2018 |
JP |
2018-160320 |
Claims
1. An outer case for a hot water unit configured using a metal
plate, the outer case comprising: a paint layer provided to cover
at least one of a front surface and a back surface of the metal
plate; an inkjet printing layer which is laminated on the paint
layer and represents at least one of text, symbols, figures or a
pattern; and a clear layer which covers the inkjet printing
layer.
2. The outer case for a hot water unit according to claim 1,
wherein the clear layer contains an ultraviolet absorber.
3. The outer case for a hot water unit according to claim 1,
wherein the outer case includes an outer case main body having an
opening on at least one surface, and a cover body attached to the
outer case main body to close the opening, and at least one of the
outer case main body and the cover body has a configuration in
which the paint layer, the inkjet printing layer, and the clear
layer are provided on an outer surface of the metal plate.
4. The outer case for a hot water unit according to claim 1,
wherein the metal plate is provided with a drawing portion, and in
a portion of the drawing portion in which a plate thickness of the
metal plate is thinner than that of another portion, a thickness of
the inkjet printing layer is also thinner than that of the other
portion.
5. The outer case for a hot water unit according to claim 1,
wherein the metal plate is provided with a burring hole into which
a burring portion protrudes on a peripheral portion, a first inkjet
printing layer provided in a peripheral portion of the burring hole
and a second inkjet printing layer provided in the burring portion
to be connected to the first inkjet printing layer are included as
the inkjet printing layer, and the first inkjet printing layer and
the second inkjet printing layer are covered serially by the clear
layer.
6. The outer case for a hot water unit according to claim 1,
wherein at least some component parts of the outer case are pressed
products, and a positioning mark for pressing of the component
parts is provided as the inkjet printing layer.
7. A hot water unit comprising the outer case for a hot water unit
according to claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to a hot water unit in which a
hot water device for generating hot water or storing hot water,
such as a hot water supply device or a cogeneration system, is
accommodated in an outer case, and the outer case.
BACKGROUND ART
[0002] As a specific example of a hot water unit configured as a
hot water supply device, there is an example in which a hot water
device, which heats water using combustion gas generated by a
burner, is accommodated in an outer case (for example, see Patent
Literatures 1 to 3). The outer case for the hot water unit is
generally manufactured by pressing a colored steel plate having a
front surface of a single color.
[0003] In such a hot water unit, for example, in addition to
displaying text or symbols representing a manufacturer name, a
type, an ability or the like of the hot water unit on the outer
case, in some cases, a wide range of the surface of the outer case
needs to be covered with a color different from a ground color of
the surface of the colored steel plate. In this case, in the
related art, after forming component parts of the outer case (an
outer case main body and a cover body) by press molding, the
component parts are painted by a spray method.
[0004] However, in the above-mentioned related art, there is the
following room for improvement.
[0005] When the spray-type painting means of the related art is
used, masking of an unpainted portion and color matching of the
paint are troublesome. In addition, work of spraying paint using a
spray gun (an air gun) is also troublesome and requires skill.
Therefore, workability and productivity are poor. Furthermore,
since the paint is sprayed onto the masking portion, much paint is
wasted. Therefore, the manufacturing cost of the outer case and the
manufacturing cost of the hot water unit increase. As the pattern
to be painted becomes more complicated and the number of colors
increases, such defects become remarkable. According to some spray
methods, it is also difficult to express detailed patterns.
[0006] In the related art, a transfer type coating means has also
been appropriately adopted. However, according to the coating means
of this transfer method, a transfer plate is required, which leads
to a high cost. Moreover, it is not suitable for painting a large
area.
[0007] On the other hand, the paint applied to the outer case is
easily damaged by influences of wind and rain or sunlight including
ultraviolet rays, and contamination and fading are likely to
occur.
CITATION LIST
Patent Literature
[0008] [Patent Literature 1]
[0009] Japanese Patent Laid-Open No. 2012-32029 [0010] [Patent
Literature 2]
[0011] Japanese Patent Laid-Open No. H11-294867 [0012] [Patent
Literature 3]
[0013] Japanese Patent Laid-Open No. 2014-40950
SUMMARY OF INVENTION
Technical Problem
[0014] An objective of the present invention is to provide an outer
case for a hot water unit capable of appropriately solving the
above-mentioned problems, and a hot water unit provided with the
outer case.
Solution to Problem
[0015] In order to solve the above problems, the following
technical measures are taken in the present invention.
[0016] An outer case for a hot water unit provided in a first
aspect of the present invention is an outer case for a hot water
unit configured using a metal plate, which includes a paint layer
provided to cover at least one of a front surface and a back
surface of the metal plate; an inkjet printing layer which is
laminated on the paint layer and represents at least one of text,
symbols, figures or a pattern; and a clear layer which covers the
inkjet printing layer.
[0017] Preferably, the clear layer contains an ultraviolet
absorber.
[0018] Preferably, the outer case includes an outer case main body
having an opening on at least one surface, and a cover body
attached to the outer case main body to close the opening, and at
least one of the outer case main body and the cover body has a
configuration in which the paint layer, the inkjet printing layer,
and the clear layer are provided on the outer surface of the metal
plate.
[0019] Preferably, the metal plate is provided with a drawing
portion, and in a portion of the drawing portion in which a plate
thickness of the metal plate is thinner than that of another
portion, a thickness of the inkjet printing layer is also thinner
than that of the other portion.
[0020] Preferably, the metal plate is provided with a burring hole
into which a burring portion protrudes on the peripheral portion, a
first inkjet printing layer provided in a peripheral portion of the
burring hole and a second inkjet printing layer provided in the
burring portion to be connected to the first inkjet printing layer
are included as the inkjet printing layer, and the first and second
inkjet printing layers are covered serially by the clear layer.
[0021] Preferably, at least some component parts of the outer case
are pressed products, and a positioning mark for pressing of the
component parts is provided as the inkjet printing layer.
[0022] A hot water unit provided in a second aspect of the present
invention includes the outer case for the hot water unit provided
in the first aspect of the present invention.
[0023] Other features and advantages of the present invention will
become more apparent from the following description of embodiments
of the invention with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1A is a side view representing an example of a hot
water unit according to the present invention, and FIG. 1B is an
exploded perspective view of an outer case (a state in which an
internal hot water device is omitted) of the hot water unit shown
in FIG. 1A.
[0025] FIG. 2A is a side view of a state in which a clear layer is
omitted in FIG. 1A, and FIG. 2B is an exploded perspective view of
a state in which the clear layer is omitted in FIG. 1B.
[0026] FIG. 3A is a front view of a state in which the clear layer
of the cover body of the outer case shown in FIGS. 1A and 1B is
omitted, and FIG. 3B is a front view of a state in which an inkjet
printing layer of the cover body is omitted.
[0027] FIG. 4A is a cross-sectional view along a line IVA-IVA of
FIG. 3A, FIG. 4B is a cross-sectional view of a main part along a
line IVB-IVB of FIG. 3A, FIG. 4C is a cross-sectional view of a
main part along a line IVC-IVC of FIG. 3A, and FIG. 4D is a front
sectional view of a portion indicated by reference numeral IVD of
FIG. 3A.
[0028] FIG. 5 is a rear view of the cover body shown in FIGS. 1A to
3A.
[0029] FIGS. 6A to 6G are explanatory views representing an example
of the manufacturing process of the cover body shown in FIGS. 1A to
3A.
[0030] FIG. 7 is a cross-sectional view of a main part which shows
an example of a colored steel plate used for manufacturing the
cover body shown in FIGS. 1A to 3A.
[0031] FIG. 8A is a perspective view representing an example of a
schematic configuration of a printer used for inkjet printing, and
FIG. 8B is a view taken along an arrow VIIIB of FIG. 8A,
representing a schematic structure of a print head of the printer
shown in FIG. 8A.
[0032] FIG. 9 is cross-sectional view of the main part which shows
an example of the working process for obtaining a structure of FIG.
4C.
DESCRIPTION OF EMBODIMENTS
[0033] Hereinafter, preferred embodiments of the present invention
will be specifically described with reference to the drawings.
[0034] A hot water unit U shown in FIGS. 1A to 2B corresponds to a
hot water supply device and includes an outer case C, and a hot
water device 1 for generating hot water is accommodated inside the
outer case C. The hot water device 1 is equipped with a heat
exchanger 10 through which hot water flows, a burner 11 for heating
the hot water in the heat exchanger 10, and a fan 12 for supplying
combustion air to the burner 11.
[0035] The outer case C is equipped with a substantially
rectangular parallelepiped outer case main body 2 having an opening
20 on a front surface, and a cover body 3 (a front cover body) that
closes the opening 20. The cover body 3 is detachably attached to
the front surface portion of the outer case main body 2 by
utilizing, for example, a screw body 9 such as a screw, and screw
body insertion holes 31 and 21 through which the screw body 9 is
inserted.
[0036] In the present embodiment, the cover body 3 is provided with
an inkjet printing layer 4 (a portion having a halftone dot pattern
or a wavy line pattern in the drawing) and a clear layer 5. The
outer case main body 2 is not provided with these. Therefore, the
configuration of the cover body 3 will be described below in
detail, and the description of the outer case main body 2 will be
omitted. However, as will be described below, an inkjet printing
layer or a clear layer can be provided on the outer case main body
2.
[0037] The cover body 3 is a configuration in which an inkjet
printing layer 4 (4a to 4g) (see also FIGS. 3A and 5), and the
clear layer 5 are provided on the colored steel plate 30 after
press-molding (a metal plate provided with a paint layer).
[0038] The cover body 3 has a panel shape having a substantially
rectangular shape in a front view, and is equipped with an outer
peripheral flange portion 32, and a bulging portion 33 which is
surrounded by the outer peripheral flange portion 32 and bulges to
the front of the outer peripheral flange portion 32 (a front side
of the outer case C). The outer peripheral flange portion 32 is a
portion for abutting on the substantially rectangular frame-shaped
flange portion 22 provided on the front surface portion of the
outer case main body 2, and as shown in FIG. 4A, a folded-back
portion 32a formed by hemming process is continuously provided on
the outer edge portion thereof.
[0039] The bulging portion 33 of the cover body 3 occupies most of
the cover body 3, and the bulging portion 33 is provided with an
air supply port 34 and an exhaust port 35 (see also FIGS. 3A and
3B). The air supply port 34 is a portion that allows outside air to
flow into the outer case C. The exhaust port 35 is a portion for
discharging the exhaust gas after heat recovery by the heat
exchanger 10 to the outside of the outer case C. As shown in FIG.
4C, the exhaust port 35 is formed as a burring hole on the
peripheral edge portion of which a tubular burring portion 35a is
continuously provided.
[0040] The inkjet printing layer 4 is a coating film layer provided
by utilizing an inkjet printer 8 as will be described below. As the
ink for inkjet printing, a water-based pigment ink or a
solvent-based pigment ink can be used. Preferably, the ink contains
an ultraviolet curable resin and a thermosetting resin.
[0041] Inkjet printing layers 4a to 4d representing a predetermined
pattern D1 such as a penguin, and an inkjet printing layer 4e
representing text D2 ("AABBCC" as an example in the drawing)
indicating, for example, a maker, a model or a trademark of the hot
water unit U provided on the surface of the cover body 3 are
provided as the inkjet printing layer 4. An inkjet printing layer
4f representing a positioning mark D3 for pressing, which will be
described later, is provided at the four corners of the cover body
3. The positioning mark D3 is shown in the shape of "+" in the
drawing, but is not limited thereto. Further, the positioning mark
D3 may be configured to be provided on the back surface of the
cover body 3 instead of or in addition to the front surface of the
cover body 3.
[0042] As shown in FIG. 5, an inkjet printing layer 4g representing
an electrical wiring diagram D4 of the hot water device 1 is
further provided on the back surface of the cover body 3. Instead
of or in addition to the electrical wiring diagram D4, it is also
possible to provide a configuration representing a piping diagram
of the hot water device 1. Although this is not illustrated or
described, it is also possible to provide a configuration in which
an inkjet printing layer representing a specification description,
notes, or the like of the hot water unit U is further provided on
the back surface of the cover body 3, in addition to the electrical
wiring diagram D4 and the piping diagram.
[0043] As shown in FIG. 7, the colored steel plate 30 is a raw
material of the cover body 3 and has a multi-layer structure with a
plated steel sheet 30a (metal plate), a whitish (or white) coating
layer 30b on a front side laminated on the surface of the plated
steel sheet 30a, and a coating layer 30c on a back side as a
service coat laminated on the back surface of the plated steel
sheet 30a. The inkjet printing layers 4a to 4e have colors
different from those of the whitish front side coating layer 30b,
and represent a design D1 such as the appearance of the penguin and
text D2. The white portion of FIG. 3A is a portion of the front
side coating layer 30b of the colored steel plate 30 that has not
been subjected to inkjet printing.
[0044] The entire region of the inkjet printing layer 4a is
basically formed in the same color and to the same thickness.
However, as shown in FIG. 4D, a thickness ta of a corner portion
33a' of a peripheral wall portion 33a (a wall portion rising
forward from the outer peripheral flange portion 32) of the bulging
portion 33 is thinner than a thickness tb of another portion of the
peripheral wall portion 33a, and a thickness of the portion other
than the peripheral wall portion 33a. The bulging portion 33 is
formed by the drawing process, and the peripheral wall portion 33a
thereof corresponds to the drawing portion. According to the
drawing process, an amount of extension of the color steel plate 30
of the corner portion 33a' of the peripheral wall portion 33a is
the largest (the corner portion 33a' corresponds to a `portion in
which the plate thickness of the metal plate is thinner than other
portions, in the drawing portion`). If the thickness ta of the
inkjet printing layer 4a in the corner portion 33a' decreases
accordingly, it is possible to obtain the effect of preventing the
inkjet printing layer 4a from peeling, as will be described later.
When the amount of drawing (the amount of extension) of the
peripheral wall portion 33a is increased to increase the amount of
bulging of the bulging portion 33, it is possible to provide a
configuration in which the thickness tb of the portion of the
peripheral wall portion 33a other than the corner portion 33a' is
thinner than the thickness of other portions of the inkjet printing
layer 4a.
[0045] The inkjet printing layer 4b is provided in the peripheral
portion of the exhaust port 35. As described with reference to FIG.
4C, the exhaust port 35 is formed as a burring hole having a
burring portion 35a. In contrast, a part of the inkjet printing
layer 4b is also provided on the inner surface of the burring
portion 35a. As a result, the peripheral portion of the exhaust
port 35 and the inner surface of the burring portion 35a can be
aligned in the same color or pattern, and the appearance of the
exhaust port 35 and its peripheral portion can be improved.
[0046] The inkjet printing layer 4e is provided on the front
surface of a step pressing portion 36 (see also FIGS. 3B and 4B)
that three-dimensionally represents the text D2. More specifically,
the step pressing portion 36 is a portion in which the text D2 is
three-dimensionally formed by partially extruding a part of the
colored steel plate 30 by pressing, and the inkjet printing layer
4e is provided on the front surface portion of such a step pressing
portion 36. Although the step pressing portion 36 includes a front
convex form in which a part of the colored steel plate 30 is
extruded to the front side of the cover body 3, and a front concave
form in which a part of the colored steel plate 30 is extruded to
the rear side of the cover body 3, it does not matter which one is
adopted.
[0047] The clear layer 5 is formed over substantially the entire
region of the front surface part of the cover body 3 to cover the
inkjet printing layer 4. As shown in FIG. 4B, the clear layer 5 is
also formed in a recess in a region forming the text D2. Further,
as shown in FIG. 4C, the clear layer 5 is also provided on the
inner surface of the burring portion 35a, and serially covers the
inkjet printing layer 4 of the inner surface of the burring portion
35a, the inkjet printing layer 4 around the exhaust port 35
(burring hole) or the like. Since the back surface of the cover
body 3 is not directly exposed to wind, rain or sunlight, the clear
layer 5 is not provided. However, it is possible to provide a
configuration in which the clear layer 5 is also provided on the
back surface of the cover body 3 to protect the inkjet printing
layer 4g. In this case, instead of providing the clear layer 5 on
the entire back surface, it is possible to provide a configuration
in which the clear layer 5 is provided only in a region in which
the inkjet printing layer 4g is provided. The clear layer 5 is made
of a resin paint that does not contain a pigment, but contains an
ultraviolet absorber. Further, the clear layer 5 is made of a
thermosetting resin or an ultraviolet curable resin.
[0048] The aforementioned cover body 3 can be manufactured via the
following steps.
[0049] First, as shown in FIG. 6A, a flat plate-shaped colored
steel plate 30 described with reference to FIG. 7 is prepared as a
raw material for the cover body 3. Next, the inkjet printing layer
4 is provided as shown in FIG. 6B, by performing inkjet printing on
the colored steel plate 30 (strictly speaking, on the paint layers
30b and 30c of the colored steel plate 30). The inkjet printing is
performed using, for example, an inkjet printer 8 as shown in FIG.
8A. In the inkjet printer 8, the print head 80 is movable in the x
and y directions orthogonal to each other on the upper side of a
mounting table 81 on which the colored steel plate 30 is mounted
and supported.
[0050] As shown in FIG. 8B, the print head 80 includes a plurality
of inkjet nozzles 82 that atomize an inkjet paint of a
predetermined color and spray it toward the colored steel plate 30.
This point is the same as conventional knowledge, but a pair of
ultraviolet light sources 83 (83a, 83b) are further provided in the
vicinity of the inkjet nozzle 82.
[0051] For example, when inkjet printing is performed while the
print head 80 is moved in the x1 direction of FIG. 8B as a main
scanning direction, an ultraviolet light source 83a on the rear
side in the main scanning direction is made to emit light, and
ultraviolet rays are radiated to the region immediately after the
inkjet printing. Since the inkjet printing layer 4 contains an
ultraviolet curable resin, the inkjet printing layer 4 can be
rapidly cured (cured to the extent that bleeding does not occur,
which will be described later) by irradiation of the ultraviolet
rays.
[0052] Therefore, it is possible to prevent the uncured inkjet
printing layers 4 having different colors from being mixed with
each other and causing bleeding. When the inkjet printing is
carried out in a direction opposite to the x1 direction described
above, the same effect as described above can be obtained by
causing the ultraviolet light source 83b to emit light instead of
the ultraviolet light source 83a.
[0053] When the inkjet printing layer 4a is provided, the thickness
to of the colored steel plate 30 at a planned portion which is the
corner portion 33a' of the peripheral wall portion 33a shown in
FIG. 4D is set to be thinner than the thickness tb of other
portions.
[0054] After the above-mentioned inkjet printing on both the front
and back surfaces of the colored steel plate 30 is completed, as
shown in FIG. 6C, while heating the color steel sheet 30 and drying
the inkjet printing layer 4, the thermosetting resin contained in
the inkjet printing layer 4 is cured. The heating is performed
using, for example, a heating furnace. By such a process, the
strength of the inkjet printing layer 4 can be increased, and in
addition, the durability against the pressing to be performed
thereafter can also be improved.
[0055] Next, the colored steel plate 30 is subjected to drawing
process as a pressing to form an outer peripheral flange portion 32
and a bulging portion 33 as shown in FIG. 6D. After that, as shown
in FIG. 6E, the pressing step for forming the air supply port 34,
the exhaust port 35, the step pressing portion 36, and the like,
the trimming process for removing an excess portion of the outer
peripheral flange portion 32, a subsequent hemming process and the
like are performed. As a result, the cover body 3 described above
can be manufactured. In the above working process, the colored
steel plate 30 can be accurately positioned with reference to the
positioning mark D3. The work of forming the exhaust port 35 is
performed by utilizing a punch 7a and a die 7b, for example, as
shown in FIG. 9. In contrast, in addition to the peripheral portion
of the planned formation location of the exhaust port 35, the
inkjet printing layer 4b is also provided serially at the formation
target portion of the exhaust port 35. Therefore, as shown in FIG.
4C, it is possible to appropriately realize a configuration in
which the inkjet printing layer 4b is provided serially from the
peripheral portion of the exhaust port 35 to the burring portion
35a.
[0056] After the outer shape of the cover body 3 is finished as
described above, as shown in FIG. 6F, the cover body 3 is subjected
to clear coating to form the clear layer 5 over substantially the
entire region of the front surface of the cover body 3. The clear
paint is mainly made of a thermosetting resin (or an ultraviolet
curable resin) containing an ultraviolet absorber. The clear
coating is, for example, a spray coating in which a clear paint is
sprayed from a spray nozzle 88. After the clear coating is
completed, the clear layer 5 is heated, dried and cured as shown in
FIG. 6G The heating is, for example, heating using a heating lamp.
Alternatively, when the clear layer 5 is made of an ultraviolet
curable resin, it is cured by ultraviolet irradiation.
[0057] Next, the operations of the outer case C provided with the
cover body 3 and the hot water unit U will be described.
[0058] First, since the design D1 such as the penguin is displayed
on the front surface portion of the cover body 3, for example, the
hot water unit U can have excellent design properties, as compared
with a case in which the surface of the cover body 3 has a single
color or no pattern. Since the inner surface of the burring portion
35a of the exhaust port 35 is continuously painted on the
peripheral portion of the exhaust port 35, the appearance is also
better than in a case in which the inside of the burring portion
35a is colored differently from the peripheral portion of the
burring portion 35a. Further, in the corner portion 33a' of the
peripheral wall portion 33a, a part of the colored steel plate 30
greatly extends in the drawing process. However, since the
thickness to of the inkjet printing layer 4 in this portion is
thinner than the thickness tb of the other portion, it is also
possible to prevent the problem of the inkjet printing layer 4
being easily peeled off in the above-mentioned drawing process.
[0059] Since the electrical wiring diagram D4 or the piping diagram
is represented by the inkjet printing layer 4g on the back surface
of the cover body 3, it is convenient for maintenance work and the
like. For example, when the means such as a sheet with a printed
electrical wiring diagram is stuck to the back surface of the cover
body 3, the sheet may be damaged or peeled off of the cover body 3
and lost. In contrast, according to the present embodiment, there
is no such risk.
[0060] Since the coating film layer representing the design D1, the
text D2, the positioning mark D3, the electrical wiring diagram D4,
and the like of the cover body 3 is all included in the inkjet
printing layer 4, it can be easily provided using the inkjet
printer 8 as described above.
[0061] For example, unlike painting by the spray method, a masking
process and color matching of paint are not required, and skill is
not required. Therefore, it is possible to improve workability and
productivity. In addition, it is easy to change the design of the
design D1 and the like, and it is suitable for small-quantity and
large-variety production. Further, according to the inkjet
printing, there is little to no waste of ink paint, and it is
economical. Since the base material of the inkjet printing layer 4
is the paint layers 30b and 30c of the colored steel plate 3, it is
also possible to improve the appearance, weather resistance or the
like of the location in which the inkjet printing layer 4 is not
provided.
[0062] The clear layer 5 enables various expressions such as glossy
and matte, and further improves the design of the outer case C.
Further, since the clear layer 5 covers and protects the inkjet
printing layer 4 on the front surface portion of the cover body 3,
the weather resistance of the inkjet printing layer 4 is enhanced
and the stain resistance is excellent. In particular, since the
clear layer 5 contains an ultraviolet absorber, the color of the
inkjet printing layer 4 does not fade due to the ultraviolet rays
of sunlight. Further, the clear layer 5 also has an effect of
suppressing the peeling of the inkjet printing layer 4. Because the
clear layer 5 is provided in substantially the entire region of the
front surface portion of the cover body 3, the aforementioned
effect is more excellent.
[0063] The present invention is not limited to the content of the
above-described embodiment. The specific configuration of the outer
case for hot water unit according to the present invention and each
part of the hot water unit can be variously redesigned within the
scope intended by the present invention.
[0064] Although the above-described embodiment is an example in
which only the cover body 3 is subjected to inkjet printing or
clear coating, in the present invention, it is possible to provide
a configuration in which the outer case main body 2 is also
subjected to inkjet printing or clear coating, instead of or in
addition to this. The outer case main body may be subjected to only
the clear coating and not subjected to inkjet printing. The
specific content such as text and patterns represented by the
inkjet printing layer of the present invention is not limited, and
at least one of text, symbols, figures, and patterns may be
represented. The clear layer may be colored and transparent instead
of colorless and transparent.
[0065] The hot water unit according to the present invention can
also be configured as a hot water storage tank unit or the like in
which a hot water device for storing hot water, such as a hot water
storage tank, is accommodated in the outer case, instead of a
configuration in which a hot water device for generating hot water
such as a hot water supply device is accommodated in the outer
case. Therefore, the outer case is not limited to a combination of
the front opening-shaped outer case main body and the cover body
that closes the front opening.
[0066] Although a flat metal plate is used as the material of the
outer case, it is possible to use a material different from the
commercially available colored steel plate as the metal plate.
* * * * *