JP7784163B2 - Decorative mirror manufacturing method and decorative mirror - Google Patents

Description

The present invention relates to a decorative mirror with a high-quality image printed in color on the glass surface, and a method for manufacturing the same.

American cafes and bars often feature decorative items known as pub mirrors. A pub mirror is a decorative item with pictures or text painted on the surface of a mirror, and is hung on the wall or displayed on a shelf to create a stylish atmosphere in the bar.

Meanwhile, in Japan, these types of products are becoming more popular, and are not only used to decorate restaurants and izakayas, but are also attracting attention from individuals as products featuring their favorite anime characters.

Japanese Utility Model Application Publication No. 57-142971 JP 2016-106674 A Japanese Patent Application Publication No. 10-127449 Utility Model Registration No. 3182102 Japanese Patent Application Publication No. 06-030832

However, fixing pictures or letters to glass is not easy, and ink on the glass surface tends to peel off easily. For this reason, methods generally used include printing pictures or letters on the back of the glass (Patent Documents 1 and 2), or attaching a printed sheet to the glass surface (Patent Documents 3 and 4).

There is also literature describing a technique for thermally transferring an image onto the glass surface (Patent Document 5). However, in this invention, in order to leave the exposed glass area where the mirror finish is exposed, it is necessary to partially apply a masking film coated with an adhesive to the glass surface prior to the primer process, and due to the nature of the masking film, it is not possible to create fine patterns such as letters.

Furthermore, in this invention, the image thermally transferred from a transfer sheet printed with an image of wood grain, stone grain, etc. is merely a simple, repeated decoration that decorates the periphery of the mirror surface, lacking impact, and does not utilize the thickness of the mirror to create a three-dimensional effect.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a decorative mirror with a high-quality image printed in color on the glass surface, as well as a method for manufacturing such a decorative mirror.

In order to achieve the above object, the decorative mirror of the present invention is composed of a glass substrate with a reflective layer on the back surface and a transparent or translucent primer layer on the front surface , or an auxiliary substrate with a reflective layer integrated with the glass substrate with the primer layer , wherein the glass substrate contains 60 to 80 wt% silicon dioxide (SiO2) and 2 to 20 wt% calcium oxide (CaO) as constituent materials, has a nominal thickness of 0.3 to 8 mm, and is polished to an arithmetic mean roughness Ra = 0.0007 to 0.0025 μm and then provided with the primer layer . The glass substrate has a key area in the design and a non-key area in the design, and when the design is viewed from the viewing direction, a color ink layer made of ultraviolet-curable ink and a white ink layer made of ultraviolet-curable ink behind it are formed in the key area, while the color ink layer is formed in the non-key area without the white ink layer laminated thereon.

Furthermore, the present invention typically includes a polishing step in which the surface of the glass substrate, which contains 60 to 80 wt % silicon dioxide (SiO ₂ ) and 2 to 20 wt % calcium oxide (CaO) as constituent materials and has a nominal thickness of 0.3 mm to 8 mm, is polished to an arithmetic mean roughness Ra of 0.0007 to 0.0025 μm; a priming step in which a transparent or translucent primer layer is formed on the surface of the glass substrate after the polishing step ; a priming step in which , after the priming step, white ink is partially printed and cured with ultraviolet light to make key areas of the design white; and a color printing step in which color ink is printed and cured with ultraviolet light on the surface of the primer layer other than the key areas and on the surface of the key areas that have undergone the priming step .

Although not particularly limited, in the present invention, the priming process and color printing process are preferably carried out using one or more inkjet printers. Furthermore, it is even more preferable that the primer process also be carried out using an inkjet printer.

By inkjet printing the primer, it is possible to form any exposed area of the glass mirror surface where there is no primer layer (i.e., exposed glass area). In other words, by inkjet printing the primer, it is possible to form any shape of exposed glass area, even with fine and complex patterns such as letters or logos.

In general, inkjet printers use pressure and heat to break down ink into fine particles, which are then sprayed onto a printing substrate. However, in the present invention, it is preferable to use a configuration in which a UV curing process is performed immediately after the printing process. After UV curing, the ink should preferably have a pencil hardness of approximately 3H based on JIS K-5400 8.4.

In any case, the present invention includes a polishing process to polish the glass substrate, which ensures that even minor oil stains and fingerprints that are not visible to the naked eye are removed, significantly improving the quality of the final finish. However, if a polishing process is not included, stains that are not visible to the naked eye may become visible due to the influence of the ink that is printed subsequently.

In addition, with this invention, a priming process is carried out prior to the color printing process, in which key areas of the design are painted white. This means that a silhouette of the key areas of the design is formed on the back of the glass through the thickness of the glass plate, resulting in the key areas appearing slightly raised.

Here, when forming a decorative mirror from a single glass substrate, as in the first, second, and fourth examples, if the glass plate thickness is thinner than the nominal value of 2 mm (actual measured value approximately 1.7 to 2.3 mm), the floating effect is somewhat lacking and there are strength issues. On the other hand, if the glass plate thickness is 8 mm or more, it becomes heavy and looks somewhat unnatural.

Therefore, when forming a decorative mirror from a single glass substrate, a nominal glass thickness of 3 mm (actual measurement: approximately 2.7 mm to 3.3 mm) or 5 mm (actual measurement: approximately 4.7 mm to 5.3 mm) is preferable, and a nominal glass thickness of approximately 2.0 mm to 8.0 mm, and optimally, a nominal glass thickness of approximately 3 mm, should be selected.

On the other hand, when forming a decorative mirror by laminating the first and second substrates, as in the third and fifth embodiments, the first substrate reinforces the second substrate, so from the perspective of weight reduction, the thickness of the glass substrate should be 2 mm or less (preferably 1 mm or less), and the thickness can be reduced to around 0.3 mm.

While there are no particular limitations on the white ink, a suitable ink is one containing 40-60 wt% photosensitive resin, 10-20 wt% acrylic ester, and 5-10 wt% phosphine oxide derivative. Suitable examples of acrylic ester include ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate.

Furthermore, white ink should preferably contain titanium oxide as a pigment. However, white ink with this composition has poor adhesion to glass, so to prevent peeling, it is essential to provide a primer layer on the glass substrate. Note that poor adhesion to glass is not limited to white ink; it applies to other color inks as well.

The primer can be any material that has excellent adhesion to glass, but a suitable primer is one that contains acrylic esters, photosensitive resins, and phosphine oxide derivatives in a total amount of 98-99.9 wt%. It is also preferable for the primer to further contain a polymerization inhibitor.

In either case, the primer layer should be transparent or translucent, and because the primer layer is transparent or translucent, it is possible to create a difference in transparency between the key areas of the design drawn on top of the base layer and the background areas of the design where no base layer is provided. In other words, the slightly transparent background area and the opaque key areas are clearly distinguished visually, making the key areas more clearly appealing. The key area is, for example, a display area for an anime character or the like, and is preferably located approximately in the center of the glass surface, with the surrounding area being the background.

There are no particular restrictions on the thickness of the white ink film, but it should preferably be between 20 μm and 50 μm, and more preferably around 30 μm. Achieving a film thickness of this magnitude prevents the colors of subsequent color inks from showing through the glass, and also allows for a more natural finish to the color printed surface.

While it is generally preferable to print white ink directly onto the primer layer, this does not mean that it is prohibited to print it over a black or colored layer that has already been printed on the primer layer. If white ink is printed directly onto the primer layer, a white silhouette will be formed on the back of the glass, but by printing black ink onto the primer layer, a black silhouette can be formed on the back of the glass.

However, if color inks are printed using the inkjet method on top of the black ink layer used to create the black silhouette in order to achieve the original design, the color ink particles will get caught between the fixed black ink particles, making the color dull and resulting in an unsatisfactory finish. Therefore, in this case, one or two white ink layers with a thickness of approximately 30 μm should be placed on top of the black ink layer, and then color inks should be printed to achieve the original design.

Similarly, by printing color ink on the primer layer, a silhouette similar to that on the front side can be created on the back side of the glass. However, even with the same design, printing color inks in duplicate will make the image outline unclear, so one or two white ink layers with a thickness of approximately 30 μm should be placed on top of the color print layer printed on the primer layer, and then color ink should be printed to achieve the original design.

As described above, in addition to the embodiment in which white ink is printed directly onto the primer layer to form a white silhouette on the back side of the glass, the present invention also allows for printing black ink onto the primer layer to form a black silhouette, and for printing colored ink onto the primer layer to form a silhouette similar to that on the front side. However, when considering both manufacturing costs and the finished product, printing a layer of white ink directly onto the primer layer is generally optimal.

In any case, in the present invention, a color image is printed on the glass surface, excluding the exposed glass areas, after a color printing process. In other words, when the glass surface is viewed in plan before color printing, the glass surface is divided into a primer layer, a base layer in which white ink or the like is printed on the primer layer, and the exposed glass areas where no primer is present; however, a color image is printed on the primer layer and base layer, excluding the exposed glass areas.

Here, the film thickness of the color ink should be between 20 μm and 50 μm, and more preferably around 30 μm.

The color inks used in the color printing process include at least cyan, magenta, yellow, and black inks. These inks are not particularly limited as long as they are ultraviolet (UV) curable inks, but a suitable cyan ink is one whose main components are 1-20 wt% photosensitive resin, 60-90 wt% acrylic esters, and 1-20 wt% phosphine oxide derivatives, with 1-5% pigment. The pigment is preferably a copper compound. It should also contain a photopolymerization initiator and a polymerization inhibitor.

A photopolymerization initiator is a component that generates active species upon exposure to light and initiates the polymerization reaction of a photopolymerizable monomer. Examples include radical photopolymerization initiators and cationic photopolymerization initiators. Furthermore, in this invention, the inclusion of a polymerization inhibitor significantly inhibits the polymerization of the photopolymerizable monomer, improving the storage stability and durability of the ink.

The above points also apply to magenta ink and yellow ink, and these inks should preferably contain a photopolymerization initiator as well as a polymerization inhibitor. Furthermore, the main components are 1-20 wt% photosensitive resin, 60-90 wt% acrylic esters, and 1-20 wt% phosphine oxide derivatives, with magenta ink preferably containing 1-5% magenta colorant, and yellow ink preferably containing a nickel compound pigment.

The black ink contains 1-5% carbon black as a colorant, and preferably also contains a photopolymerization initiator and a polymerization inhibitor. It also preferably contains 1-10 wt% photosensitive resin, 60-90 wt% acrylic esters, and 5-10 wt% phosphine oxide derivatives.

After the color printing process, the glass surface may be covered with an appropriate protective layer or anti-reflective layer. However, to enhance the overall color and luster of the design, it is effective to print a 30 μm thick gloss material over the entire glass surface, which acts as a protective layer. It is preferable that the gloss material be UV-curable, and that the hardness after UV curing be approximately 3H pencil hardness based on JIS K-5400 8.4.

The glass substrate is not particularly limited as long as it is made up of 60 to 80 wt% silicon oxide (SiO ₂ ) and 2 to 20 wt% calcium oxide (CaO), but preferably, a glass material containing 60 to 80 wt% silicon oxide (SiO ₂ ), 0 to 7 wt% aluminum oxide (Al ₂ O ₃ ), 2 to 18 wt% calcium oxide (CaO), 0 to 8 wt% magnesium oxide (MgO), and a total of 5 to 25 wt% sodium oxide (Na ₂ O) and potassium oxide (K ₂ O) should be used.

Here, the content of iron oxide (Fe ₂ O ₃ ) should be kept to 1 wt % or less, and if the content is kept to 0.05 wt % or less, it is possible to manufacture a product with high transmittance and an even more luxurious feel.

To enhance the sense of luxury, it is preferable to include a transfer process following the color printing process, in which metal foil is thermally transferred to the required locations. In this case, a metal foil sheet with metal foil evenly adhered thereto is placed over the color ink layer, and the metal foil is thermally transferred by irradiating the metal foil sheet with laser light in a spot pattern. It is also preferable to transfer the metal foil using heat and pressure instead of laser light. In these cases, the color ink layer is already laminated on the glass substrate, so the metal foil can be thermally transferred.

The present invention described above makes it possible to create a decorative mirror with high-quality images printed in color on the glass surface.

1 is a diagram illustrating a first embodiment; 10 is a diagram illustrating a second embodiment; 10 is a diagram illustrating a third embodiment.

The manufacturing method for the decorative mirror of the embodiment will be explained in more detail below, but the specific description does not limit the present invention in any way. First, Figure 1(a) is a flow diagram that shows an outline of the manufacturing method of the first embodiment, and Figures 1(b) and 1(c) are cross-sectional views of a glass substrate showing the manufacturing process in progress.

Figure 1(a) shows the manufacturing process after a reflective layer made of aluminum or silver is formed on the rear surface of the glass. The reflective layer is formed, for example, by vacuum deposition, and Figure 1(b) shows a glass substrate 1 with a reflective layer 2 provided on it.

The thickness of the glass substrate 1 is not particularly limited, but a nominal value of 3 mm (actual measurement: approximately 2.7 mm to 3.3 mm) is preferably selected. This glass substrate is brush-cleaned with warm water to remove surface dirt (ST10), and then cut to an appropriate size (ST11). The cut size is not particularly limited, but preferably sizes of approximately A2 (420 x 594 mm), A3 (297 x 420 mm), A4 (210 x 297 mm), or B5 (182 x 257 mm) are selected.

Once the above cutting process (ST11) is complete, the glass is polished and cleaned using cesium (ST12). Specifically, the glass surface that will become the printing surface is polished using cerium oxide particles with a particle size of approximately 1.2 to 1.4 μm. As a result of this polishing process, all glass powder generated during the cutting process, including any adhesions to the glass surface, is completely removed. Fingerprints and other oily contaminants are also completely removed.

The arithmetic mean roughness (Ra) of the glass surface after polishing is approximately 0.0007 to 0.0025 μm, preferably 0.0011 to 0.0020 μm, and more preferably 0.0011 to 0.0016 μm.

Next, a transparent primer layer 3 is applied to a thickness of approximately 30 μm on the flattened glass substrate (ST13). The primer can be applied by coating or spraying a primer liquid onto the glass surface, but to leave a fine pattern on the exposed glass, it is preferable to inkjet print the primer. In this embodiment, steps ST13 to ST15 and step ST17 are performed using an inkjet printer.

Next, the color image manuscript depicting the anime characters or the like is subjected to appropriate color correction, and the key area depicting the characters or the like is extracted from the color-corrected image manuscript. Image data specifying the key area is then supplied to the printer, and instructions are given to print this key area in white ink.

As a result, a white undercoat layer 4 of approximately 30 μm is formed in the key areas of the glass surface on which the primer layer 3 was applied (ST14). In this step ST14, ultraviolet-curable white ink is used, and after the key areas are inkjet-printed in white, they are irradiated with ultraviolet light, which quickly cures the key areas.

Next, the image data of the color-corrected image original, which is composed of a main area and a background area, is supplied to the printer, and the original image is color-printed on the glass surface (excluding the exposed glass area) divided into the base layer 4 and primer layer 3 (ST15). Cyan, magenta, yellow, and black inks are used for color printing, all of which are UV-curable inks.

After each part is inkjet printed in the appropriate color, ultraviolet light is applied, quickly curing the color ink. This color ink layer 5 also has a thickness of about 30 μm, and Figure 1(c) shows a cross section of the glass substrate after processing in step ST15.

Next, the metal foil is thermally transferred onto the UV-cured color ink (ST16). Specifically, the glass substrate processed in step ST15 is placed in a thermal transfer machine, and a metal foil sheet is placed where the metal foil is to be transferred. Then, by sending position data indicating the transfer position from a computer, laser light is irradiated onto the required location, and the metal foil from the metal foil sheet is thermally transferred onto the color ink (ST16).

Although not particularly limited, letters, symbols, logos, etc. can be printed near one of the four corners of the glass surface by thermally transferring metal foil.

Finally, an inkjet printer is used to print a glossy material to increase the gloss (ST17). If gloss is not required, an appropriate protective layer can be provided instead of the glossy layer. The hardness of the glossy layer and protective layer should be approximately 3H in pencil hardness based on JIS K-5400 8.4.

As described above, in the first embodiment, the primer process (ST13) and undercoat process (ST14) are carried out prior to the color printing process (ST15). This allows the silhouette of the key areas of the design to be formed on the back surface of the glass through the thickness of the glass plate, resulting in the key areas appearing slightly raised. Furthermore, the polishing process (ST12) is carried out first, eliminating the risk of unintended patterns appearing.

The above describes an example in which the base layer 4, which is the main area, is white, but it is also preferable to paint the base layer black or its original color. Figure 2 is a flow chart explaining this second example.

The processing of steps ST10 to ST13 is the same as in the first embodiment, but in the base printing process (ST14), the base layer, which is the main area, is divided into a silhouette layer 6 and a white layer 4.

First, black or colored ink is printed on the main areas where characters and other images are drawn to form silhouette layer 6, and then white ink is printed to cover silhouette layer 6, forming white layer 4. Note that when each ink layer is approximately 30 μm thick, white ink particles can get into the gaps between the black or colored ink particles, resulting in a dull color such as gray. Therefore, it is preferable to form two white layers 4 to create a clear, solid base layer.

After the white base layer 4 has been formed in this way, the image data of the color-corrected image original, consisting of the main area and background area, is supplied to a printer, and the image original is color-printed on the glass surface (excluding the exposed glass area) divided into the base layer 4 and primer layer 3 (ST15). Subsequent processing is the same as in the first embodiment. This embodiment has the effect of forming a black or natural-colored silhouette of the main area of the design on the back surface of the glass, through the thickness of the glass plate.

In the first and second embodiments described above, a single glass substrate is configured with a reflective layer 2 on its rear surface and a color print layer (3, 4, 5, 6, etc.) on its front surface, but this is not particularly limited.

For example, as shown in Figure 3, a first substrate BS1 (see Figure 3(a)) with a reflective layer 2 on its front or back surface and a second substrate BS2 (see Figure 3(b)) without a reflective layer may be prepared, and a color print layer (3-5 or 3-6, etc.) may be provided on the front or back surface of the second substrate BS2. In this third embodiment, the second substrate BS2 is made of a glass material, but the first substrate BS1 is not necessarily limited to a glass material and may also be made of a plastic material.

In the third embodiment shown in FIG. 3, the first substrate BS1 and the second substrate are preferably made of the above-mentioned preferred glass material, i.e., a glass material containing 60 to 80 wt% silicon oxide (SiO ₂ ), 0 to 7 wt% aluminum oxide (Al ₂ O ₃ ), 2 to 18 wt% calcium oxide (CaO), 0 to 8 wt% magnesium oxide (MgO), and a total of 5 to 25 wt% sodium oxide (Na ₂ O) and potassium oxide (K ₂ O).

However, the first substrate BS1 and the second substrate BS2 may be made of glass materials with compositions other than those described above, and a plastic material may be used for the first substrate BS1 instead of a glass material. Using a plastic material for the first substrate BS1 makes it lighter than using a glass substrate, and also has the advantage of being less likely to break because the glass second substrate BS2 is reinforced by the plastic first substrate BS1.

For this reason, when using a glass material, it is preferable to set the thickness of the second substrate BS2 and/or the first substrate BS1 to approximately 0.3 mm to 1.0 mm.

In the third embodiment, when a plastic material is used for the first substrate BS1, it is preferable to use a plastic material with a film mirror attached to one of the front and back surfaces, or a plastic material with a specular reflective layer 2 vapor-deposited on one of the front and back surfaces. Here, a film mirror refers to, for example, a polyester film with a mirror finish.

Preferred examples of plastic materials include ABS resin (Acrylonitrile butadiene styrene), which has excellent rigidity, chemical resistance, and heat resistance; PET resin (Polyethylene terephthalate), which has excellent transparency, toughness, rigidity, and heat resistance; and PMMA (Polymethyl methacrylate), which has particularly excellent transparency and durability, as well as acrylic resin.

Furthermore, regardless of whether the first substrate BS1 is made of glass or plastic, the contact surfaces of the first substrate BS1 and the second substrate BS2 do not necessarily need to be fixed by adhesive or other means. If they are not fixed, the edges of the two overlapping substrates BS1 and BS2 can be held in place by an appropriate holding part FIX. They may also be held directly by a frame or other member, but in either case, when using a glass material for the first substrate BS1, it is preferable to keep the total glass thickness t1 + t2 to approximately 2 mm to 5 mm by making the thickness t1 of the first glass substrate BS1 thinner than the thickness t2 of the second glass substrate BS2.

Although it is not within the scope of this invention, from the perspective of reducing weight, it is also preferable to use a mirror-finished polyester film (film mirror) as the first substrate BS1, and to ultimately reduce weight and increase breakage strength, a plastic material such as acrylic resin may also be used for the second substrate BS2.

1 Glass substrate 2 Reflective layer 3 Primer layer 4 White ink layer 5 Color ink layer

Claims (1)

A decorative mirror is constructed by a glass substrate having a reflective layer on the back surface and a transparent or semi-transparent primer layer on the front surface , or by integrating an auxiliary substrate having a reflective layer with the glass substrate having the primer layer ,
The glass substrate contains 60 to 80 wt % of silicon dioxide (SiO2) and 2 to 20 wt % of calcium oxide (CaO) as constituent materials, and has a nominal thickness of 0.3 to 8 mm;
The glass substrate, which has been polished to an arithmetic mean roughness Ra of 0.0007 to 0.0025 μm and then provided with the primer layer , is provided with a design essential region and a design non-essential region,
When the design is viewed from the viewing direction,
A decorative mirror characterized in that a color ink layer made of ultraviolet curable ink and a white ink layer made of ultraviolet curable ink behind it are formed in the essential area, while the color ink layer is formed in the non-essential area without the white ink layer being laminated thereon.