JP2022099652A - Manufacturing method of outer case for hot water unit - Google Patents

Abstract

To provide a manufacturing method of an outer case for a hot water unit, capable of simply and appropriately preventing deterioration in finishing of an inkjet printing layer provided in the outer case for a hot water unit.SOLUTION: A manufacturing method of an outer case for a hot water unit has an inkjet printing process of providing an inkjet printing layer 4 on the surface of a paint layer 30b of a metal plate 30, where the metal plate 30 is a material for forming a component of an outer case used for housing a hot water device for hot water generation or hot water storage therein. The method has an ultraviolet cleaning step of cleaning the surface of the paint layer 30b of the metal plate 30 by irradiating the surface with ultraviolet rays using an ultraviolet irradiation device 6, before performing the inkjet printing process.SELECTED DRAWING: Figure 2

Description

The present invention relates to a manufacturing method for manufacturing an outer case for a hot water unit used for accommodating a hot water device for hot water generation or hot water storage inside, for example, in a hot water unit such as a water heater or a cogeneration system. ..

The applicant has previously proposed the ones described in Patent Documents 1 and 2 as specific examples of the outer case for the hot water unit.
The exterior case for the hot water unit described in these documents is formed by pressing a metal plate (colored steel plate) having a paint layer on at least one side, but before this pressing process, The paint layer of the metal plate is subjected to inkjet printing to provide an inkjet printing layer. The inkjet print layer displays characters, symbols, figures, patterns, and the like.

According to such a configuration, by using an inkjet printer, it is possible to efficiently, quickly, and easily express a desired pattern on the surface of the outer case and enhance the design. Compared with the conventional spray coating, the working environment can be improved and the productivity can be significantly improved, and the effect of reducing the manufacturing cost of the hot water unit can be obtained.

However, in the above-mentioned prior art, there is room for improvement as described below.

That is, a metal plate such as a color steel plate is sold in a state of being packaged with a packaging material, and is used for adhering the packaging material to the paint layer of the metal plate when the packaging is unpacked for inkjet printing. The adhesive that was used may have adhered. In addition, fingerprint marks (sebum, etc.) of the operator's finger after unwrapping the metal plate may be attached to the paint layer.
On the other hand, in inkjet printing, the amount of one inkjet droplet is very small, and the printing film thickness by one inkjet printing is considerably thinner than, for example, general spray coating. For this reason, if adhesives or fingerprint marks of workers are attached to the paint layer, when inkjet printing is performed on these, the places where the adhesives or fingerprint marks are attached are other parts. The color may be different from the original color, such as a darker color than the original color, and the appearance of the inkjet print layer may be poor. This is not appropriate because it causes a decrease in the commercial value of the hot water unit.
As a means for solving the above-mentioned problems, for example, it is conceivable to use a solvent together and wipe off the dirt on the surface of the paint layer with a cloth or the like, but the work is not easy. In addition, by performing such work, there is a risk that the dirt will spread rather than spread.

Japanese Unexamined Patent Publication No. 2019-60508 Japanese Unexamined Patent Publication No. 2019-60509

The present invention was conceived under the above-mentioned circumstances, and the finish of the inkjet printing layer provided in the outer case for the hot water unit is caused by the stain on the surface of the paint layer as the base. It is an object of the present invention to provide a method for manufacturing an outer case for a hot water unit, which can easily and appropriately prevent the deterioration.

In order to solve the above problems, the following technical means are taken in the present invention.

The method for manufacturing an exterior case for a hot water unit provided by the present invention includes an inkjet printing step of providing an inkjet printing layer on the surface of the paint layer of a metal plate having a paint layer on at least one side. The metal plate is a method for manufacturing an outer case for a hot water unit, which is a material for forming a component of an outer case used for accommodating a hot water device for hot water generation or hot water storage inside. Therefore, before carrying out the inkjet printing step, the surface of the paint layer of the metal plate is subjected to an ultraviolet cleaning step of cleaning the surface by irradiating the surface with ultraviolet rays using an ultraviolet irradiation device. It is characterized by being.

With such a configuration, the following effects can be obtained.
That is, stains such as adhesives and fingerprint marks existing on the surface of the paint layer of the metal plate can be decomposed and removed by ultraviolet cleaning, and on the surface of the paint layer from which such stains have been removed. It is possible to provide an inkjet print layer. Therefore, it is possible to eliminate or reduce the possibility that the inkjet print layer will have an unattractive appearance due to the presence of the stain. In ultraviolet cleaning, ozone and active oxygen are generated, and it is considered that the active oxygen binds to organic substances that are stains on the surface of the coating layer and is peeled off from the surface, and is excellent in cleaning performance.

In the present invention, preferably, the exterior case includes an exterior case body having an opening on at least one surface thereof, and a cover body attached to the exterior case body so as to close the opening. The component of the outer case is the outer case main body or the cover body.

Other features and advantages of the invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings.

(A) is a side view showing an example of a hot water unit provided with an outer case manufactured by the manufacturing method according to the present invention, and (b) is an exploded perspective view of the outer case shown in (a). , (C) are Ic-Ic sectional views of (b). (A) to (d) are explanatory views showing an example of the manufacturing method according to the present invention, and correspond to a series of work steps of the manufacturing method of the cover body shown in FIG. 2 is a schematic perspective view of a main part showing an example of an ultraviolet cleaning step and an inkjet printing step shown in FIGS. 2B and 2C. It is a figure of the arrow view IV of FIG. 3, and is the figure which shows the schematic structure of the print head of the inkjet printer shown in FIG.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

In order to facilitate understanding, prior to the description of the manufacturing method of the present embodiment, the configuration of the outer case C for the hot water unit manufactured by the manufacturing method of the present embodiment and the hot water unit U provided with the outer case C will be described.

In FIG. 1, the hot water unit U is configured as a hot water supply device, and the hot water device 1 for generating hot water is housed in the outer case C. The hot water device 1 includes 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.

The outer case C includes a rectangular box-shaped case body 2 having an opening 20 on the front surface, and a cover body 3 (front cover body) that closes the opening 20. The cover body 3 is detachably attached to the front surface portion of the case body 2 by using, for example, a screw body 9 such as a screw and screw insertion holes 31 and 21 through which the cover body 3 is inserted.

In the present embodiment, the cover body 3 is provided with an inkjet printing layer 4 (printing layer 4a indicated by a halftone dot pattern, printing layer 4b indicating the characters "ABC"), and the manufacturing method of the present invention is applied. ing. The case body 2 is not provided with an inkjet printing layer, and the manufacturing method of the present invention is not applied. Therefore, hereinafter, the configuration of the cover body 3 and the manufacturing method thereof will be mainly described, and the description of the case body 2 will be omitted or simplified. However, it goes without saying that the manufacturing method of the present invention can be applied to the manufacturing of the case body 2.

The cover body 3 is configured by using a color steel plate 30 (corresponding to an example of a metal plate in the present invention), and has a panel shape having a substantially rectangular front view. The cover body 3 has an outer peripheral flange portion 32 and a bulging portion 33 that is surrounded by the outer peripheral flange portion 32 and that bulges forward (front side of the outer case C) from the outer peripheral flange portion 32. I have. The outer peripheral flange portion 32 is a portion for contacting the flange portion 22 on the front surface portion of the case body 2. The bulging portion 33 has a plurality of air supply ports 34 that allow outside air to flow into the outer case C, and exhaust gas that has been heat-recovered by the heat exchanger 10 to be discharged to the outside of the outer case C. An exhaust port 35 is provided.

As shown in FIGS. 1 (c) and 2 (a), the color steel sheet 30 is a white-based (including white) paint layer on the front side of the plated steel sheet 30a and the surface of the plated steel sheet 30a as an outer surface. It is a multi-layer structure having 30b and a paint layer 30c on the back side as a service coat laminated on the back surface as the outer surface of the plated steel sheet 30a. The cover body 3 has a paint layer 30b located on the surface side thereof, and an inkjet printing layer 4 is provided on the paint layer 30b.

The inkjet printing layer 4 (4a) is, for example, a solid-coated printing layer, and is provided over a wide range of the surface portion of the cover body 3. The inkjet printing layer 4 (4b) is a printing layer representing characters such as a logo of a manufacturer of a hot water unit U. In the drawings, it is referred to as "ABC" for convenience, but the present invention is not limited to this. The inkjet printing layer 4 is a coating film provided by using the inkjet printer 8 as described later. As the ink for inkjet printing, a water-based pigment ink or a solvent-based pigment ink can be used, but in the present embodiment, an ink containing both an ultraviolet curable resin and a thermosetting resin is used. There is.

Next, an example of the method for manufacturing the cover body 3 described above will be described.

First, as shown in FIG. 2A, a flat plate-shaped color steel plate 30 is prepared as a raw material for the cover body 3. The configuration of the color steel plate 30 is as described above.
Next, as shown in FIG. 2B, an ultraviolet cleaning step of irradiating the surface of the paint layer 30b of the color steel plate 30 with ultraviolet rays to clean the surface is carried out. In this ultraviolet cleaning step, for example, as shown in FIG. 3, the colored steel plate 30 is put on the conveyor 5 in which the belt 52 is hung between the rotating rollers 50 and 51 to allow circulation drive, and the colored steel plate is formed. 30 is carried by transporting the 30 to the ultraviolet irradiation position by the ultraviolet irradiation device 6. Ultraviolet irradiation device 6
Includes one or more ultraviolet light sources 60 that emit ultraviolet light having a wavelength of, for example, 185 to 254 nm.
The ultraviolet irradiation may be performed while the color steel plate 30 is relatively moved with respect to the ultraviolet light source 60, or a state in which the ultraviolet irradiation area by the ultraviolet light source 60 is increased and the color steel plate 30 is stopped with respect to the ultraviolet light source 60. The color steel plate 30 may be irradiated with ultraviolet rays all at once, or may be any of them.

According to the above-mentioned ultraviolet irradiation, oxygen in the air is ozone-ized and active oxygen is generated in the vicinity of the surface of the paint layer 30b of the color steel plate 30. This active oxygen binds to organic substances that are stains (adhesive, fingerprint marks of workers, etc.) on the surface of the paint layer 30b, and has a cleaning action of peeling the organic substances from the surface of the paint layer 30b. For the purpose of more effectively obtaining such an ultraviolet cleaning action, the ultraviolet cleaning target area is surrounded by an appropriate housing, a gas that is a raw material of active oxygen is supplied into the housing, and an organic substance that is a stain is used. You may use an air supply / exhaust device that discharges the gas containing the above to the outside of the housing. Further, when the paint layer 30b of the color steel plate 30 is irradiated with ultraviolet rays from above, at the same time, by using another ultraviolet light source, the paint layer 30c may be irradiated with ultraviolet rays from below. good. According to such a configuration, the paint layer 30c can be washed with ultraviolet rays at the same time, which is suitable for performing inkjet printing on the paint layer 30c as well.

After the ultraviolet cleaning step is completed, the color steel plate 30 is transferred onto the inkjet printer 8 from, for example, the conveyor 5 shown in FIG. 3, and then the inkjet printing layer 4 is provided on the paint layer 30b. Carry out the process (see also FIG. 2 (c)).
As shown in FIG. 3, 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 the mounting table 81 on which the color steel plate 30 is mounted and supported. As shown in FIG. 4, the print head 80 includes a plurality of inkjet nozzles 82 that atomize inkjet paint of a predetermined color and spray it toward the color steel plate 30, and a pair of ultraviolet light sources 83 (83a, 83b). There is. The ultraviolet light source 83 may be smaller and have a lower output than the ultraviolet light source 60 for ultraviolet cleaning described above.

In the inkjet printing process, when performing inkjet printing while moving the print head 80 in the x1 direction of FIG. 4 as the main scanning direction, the ultraviolet light source 83a on the rear side in the main scanning direction is made to emit light, and inkjet printing is performed. Immediately after the area is irradiated with ultraviolet rays. 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) by irradiation with the ultraviolet rays described above. When such a curing process is completed, the inkjet printing is executed again, and if the inkjet printing and the curing process are repeated, a plurality of inkjet printing layers 4 are overcoated to give the inkjet printing layer 4 an appropriate thickness. It is possible to have it.
When the inkjet printing is carried out in the 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.

After finishing the above-mentioned inkjet printing on the color steel plate 30, the color steel plate 30 is heated to dry the inkjet printing layer 4 and cure the thermosetting resin contained therein (not shown). .. After that, the colored steel plate 30 is subjected to drawing as a press working to form the outer peripheral flange portion 32 and the bulging portion 33 as shown in FIG. 2 (d). Along with this, a hole-drilling press process for forming the air supply port 34, an exhaust port 35, and the like, a trimming process for removing an excess portion of the outer peripheral flange portion 32, and the like are performed.

The cover body 3 described above can be appropriately manufactured by a series of work steps as described above. Here, the cover body 3 is provided with an inkjet printing layer 4, and the paint layer 30b, which is a base thereof, is subjected to ultraviolet cleaning before inkjet printing is performed, and an adhesive, fingerprint marks, etc. are obtained. The stains have been removed. Therefore, the quality of the inkjet printing layer 4 does not deteriorate due to the presence of such stains, and the cover body 3 can be made to look good.

The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each step of the method for manufacturing the outer case for the hot water unit according to the present invention can be variously changed within the scope of the present invention.

The specific wavelength and intensity of ultraviolet rays used in the ultraviolet cleaning step, the irradiation time on the surface of the paint layer of the metal plate, and the irradiation method are not limited.
The inkjet printing step may be a step of providing an inkjet printing layer, and the inkjet printing layer may represent any of characters, symbols, figures, or patterns, or may be simply a solid coating, for example. It can also be a clear layer containing no pigment.
The hot water unit referred to in the present invention is a hot water storage tank in which hot water storage equipment such as a hot water storage tank is housed in the outer case instead of a hot water supply device or the like in which hot water equipment for hot water generation is housed in the outer case. It can also be configured as a unit or the like. Therefore, the exterior case is not limited to a combination of a case body having a front opening and a cover body that closes the front opening.
As the material of the outer case, a metal plate having a paint layer is used, and as the metal plate, it is possible to use a metal plate different from the commercially available color steel plate.

U Hot water unit C Exterior case 1 Hot water equipment 2 Case body 3 Cover body 30 Color steel plate (metal plate)
30b Paint layer 4 Inkjet printing layer 6 Ultraviolet irradiation device

Claims (2)

It has an inkjet printing step of providing an inkjet printing layer on the surface of the coating layer of a metal plate having a coating layer on at least one side.
The metal plate is a method for manufacturing an outer case for a hot water unit, which is a material for forming a component of an outer case used for accommodating hot water equipment for hot water generation or hot water storage inside. ,
Before carrying out the inkjet printing step, the surface of the paint layer of the metal plate is provided with an ultraviolet cleaning step of cleaning the surface by irradiating the surface with ultraviolet rays using an ultraviolet irradiation device. A characteristic method for manufacturing an outer case for a hot water unit. The method for manufacturing an outer case for a hot water unit according to claim 1.
The exterior case includes an exterior case body having an opening on at least one surface thereof, and a cover body attached to the exterior case body so as to close the opening.
A method for manufacturing an outer case for a hot water unit, wherein the component of the outer case is the outer case main body or the cover body.

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