A method for high-light printing of black material and printed matter thereof

Abstract

The present application relates to the technical field of label, in particular to a black material high-brightness printing method and printed matter thereof. The black material high-brightness printing method comprises the following steps: S1: taking a black substrate and a coating liquid, performing corona treatment on the upper surface of the black substrate, uniformly coating the coating liquid on the upper surface of the black substrate, drying to form a coating liquid layer, and reserving; S2: taking special digital ink, coating the special digital ink on the upper surface of the coating liquid layer multiple times under infrared insulation, drying to form a multi-layer special digital ink layer, and reserving; S3: coating UV glue on the upper surface of the uppermost layer of the special digital ink layer at room temperature, and curing under the irradiation of a UV lamp to form a protective layer. The special digital ink is used for spraying variable serial numbers. The black material high-brightness printing method is simple in process and easy to control in operation, and is conducive to industrialized mass production. The printed matter prepared has a simple structure and good gloss and whiteness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of labels, in particular to a high-brightness printing method for black materials and a printed product thereof. BACKGROUND

[0002] Traditional high-brightness printing on black materials often uses silk screen printing, a special printing process that uses hot stamping equipment to transfer a white color layer to a printed product under heat and pressure, and is often used as a post-printing process to give labels a unique decorative effect. However, there have been major problems with economic efficiency, including substandard gloss, insufficient whiteness, unclear images, and insufficient richness of levels after printing multiple layers of white color. The present application uses digital printing to achieve high-brightness printing on black materials to address the shortcomings of silk screen printing. SUMMARY

[0003] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide a high-brightness printing method for black materials, which is simple in process and easy to operate, and is conducive to industrialized mass production. The method can produce printed products with stable quality, strong tensile strength, good gloss, and whiteness, strong practicality, and superior comprehensive performance.

[0004] The printed product of the present application has a simple structure and includes, from bottom to top, a black substrate, a coating liquid layer, a special digital ink layer, and a protective layer. The special digital ink layer has good gloss and whiteness, and the coating liquid has strong tensile strength, is stable in connection, and is easy to use.

[0005] The purpose of the present application is achieved by the following technical solution: a high-brightness printing method for black materials, comprising the following steps:

[0006] S1: Take black substrate and coating liquid, and perform corona treatment on the upper surface of the black substrate at room temperature. Then, uniformly coat the coating liquid on the upper surface of the black substrate at a temperature of 80-110°C, and dry it at a temperature of 80-110°C for 1-3s to form a coating liquid layer, ready for use;

[0007] S2: Take special digital ink, and coat the special digital ink on the upper surface of the coating liquid layer multiple times under infrared insulation at a temperature of 80-110°C. Dry it at a temperature of 80-110°C for 1-3s to form a multi-layer special digital ink layer, ready for use;

[0008] S3: Coat UV glue on the upper surface of the uppermost layer of the special digital ink layer at room temperature, and place it under the irradiation of a UV lamp for 0.5-3s to cure and form a protective layer.

[0009] Preferably, the number of layers of the special digital ink layer is 3-5 layers.

[0010] In the above technical solution, in step S1, the power of the corona is 1000-1200W.

[0011] In the above technical solution, in step S2, the pressure coating is applied in a Carver press with a pressure of 180-220 kg to press the corresponding thickness.

[0012] In the above technical solution, in step S3, the conditions of the ultraviolet lamp irradiation are: UV energy is 80-100j.

[0013] In the above technical solution, the thickness of the protective layer is 2-4 μm, the thickness of each of the special digital ink layers is 2-4 μm, the thickness of the coating liquid layer is 2-3 μm, and the thickness of the black substrate is 0.05-0.15 mm.

[0014] In the above technical solution, the black substrate is one of a PET film or a PP film.

[0015] The black material high-brightness printing method of the present application has a simple process, and the printed product prepared includes, from bottom to top, a black substrate, a coating liquid layer, a special digital ink layer, and a protective layer, and the special digital ink layer is formed by coating the special digital ink, the protective layer is formed by coating the UV glue, and the coating liquid layer is formed by coating the coating liquid. The special digital ink is used for spraying a variable serial number, and the relevant information of the corresponding product can be inquired through the variable serial number. The special digital ink layer has the characteristics of good gloss and whiteness, and the coating liquid has the characteristics of strong tensile strength, stable connection, and convenient use.

[0016] In the above technical solution, the special digital ink includes the following raw materials in parts by weight: titanium dioxide compound 7-8 parts, acrylic resin 15-22 parts, conductive liquid 20-45 parts, and image oil 5-10 parts.

[0017] In the above technical solution, the conductive liquid is mixed by C12-20 isoparaffin, barium sulfonate, and alkyd aryl sulfonate in a weight ratio of 8-9:1-2:0.5-0.8.

[0018] Preferably, the barium sulfonate is a barium sulfonate of type T701, the alkyd aryl sulfonate is a dodecyl benzene sulfonic acid isopropanolamine salt with a CAS number of 26264-05-1, and the C12-20 isoparaffin is a C12-20 isoparaffin with a CAS number of 64742-46-7.

[0019] In the above technical solution, the image oil is mixed by C12-20 isoparaffin and white mineral oil in a weight ratio of 17-19:1-2.

[0020] In the technical scheme, the titanium dioxide compound comprises the following raw materials by weight: titanium sulfate 22-26 parts, illite 30-35 parts, silica ash 45-55 parts, and organic silicon treatment agent 7-8 parts.

[0021] In the technical scheme, the illite has a particle size of 200-300 nm. Preferably, the illite is illite of Liaoning Yilong Mining Co., Ltd., wherein the illite contains 0.2% magnesium oxide, 20.9% aluminum oxide, 17.1% silicon dioxide, 0.02% calcium oxide, 3.6% potassium oxide, 0.3% titanium dioxide, 56.8% water, and the balance is impurities.

[0022] In the technical scheme, the silica ash has a particle size of 300-400 nm. Preferably, the silica ash is silica ash of Jiangxi Nanfang Silica Ash Co., Ltd.

[0023] In the technical scheme, the organic silicon treatment agent is mixed by hydroxy silicone oil and dimethyl silicone oil at a weight ratio of 4-5:3-4. Preferably, the hydroxy silicone oil is hydroxy silicone oil with CAS number 70131-67-8. The dimethyl silicone oil is dimethyl silicone oil with poly energy type JN-201.

[0024] In the technical scheme, the preparation method of each part of the titanium dioxide compound comprises the following steps:

[0025] E1, dispersing titanium sulfate in deionized water for hydrolysis to prepare a titanium sulfate solution with a concentration of 100-180 g / L for standby;

[0026] E2, mixing the illite and the silica ash uniformly, and then calcining at 800-900 ℃ to obtain a mixture A;

[0027] E3, after cooling to room temperature, dispersing the mixture A in deionized water and treating by ultrasonic for 30-40 minutes to obtain a slurry A;

[0028] E4, heating the slurry A to 85-95 ℃, adjusting the pH value to 1.5-1.8 with dilute sulfuric acid, and then adding the titanium sulfate solution drop by drop into the slurry A, while adding ammonia water to keep the pH value of the slurry A at 1.5-1.8, standing for 5-6 hours, filtering and washing the precipitate with distilled water, and drying at 100-110 ℃ for 9-10 hours to obtain a composite material;

[0029] E5, calcining the composite material in a high-temperature box at 850-950 ℃ for 1.5-2.5 hours to obtain a pre-product;

[0030] E6. Disperse the pre-product in deionized water, add organosilicon treatment agent, stir for 20-30 minutes, and after drying and grinding, obtain titanium dioxide composite.

[0031] In the above technical solution, the preparation method of the extra-white digital ink includes the following steps:

[0032] A1. Mix the conductive liquid and the image oil evenly to obtain mixture B;

[0033] A2. Add the titanium dioxide composite and acrylic resin to mixture B and stir for 1-3 hours to obtain extra white digital ink.

[0034] In the above technical solution, the preparation method of the coating liquid includes the following steps:

[0035] B1. Dissolve sodium alginate in deionized water and stir until homogeneous to prepare a sodium alginate solution with a mass fraction of 5-6%.

[0036] B2. Dissolve polyvinyl alcohol in deionized water and heat at 90-100℃ for 1.5-2.5 hours until the polyvinyl alcohol dissolves. Then cool the stirred solution to room temperature to prepare a polyvinyl alcohol solution with a mass fraction of 4-6%.

[0037] B3. Mix sodium alginate solution, polyvinyl alcohol solution, anhydrous calcium chloride, boric acid and waterborne polyurethane to obtain coating solution.

[0038] In the above technical solution, in step B3, the solid content of the waterborne polyurethane is 30-40%. Preferably, the waterborne polyurethane is PUR-S5718 from Huashi (Guangdong) New Material Technology Co., Ltd.

[0039] In the above technical solution, the polyvinyl alcohol used is Sinopec model 17-92.

[0040] In the above technical solution, in step B3, the weight ratio of the sodium alginate solution, polyvinyl alcohol solution, and aqueous polyurethane is 18-22:13-16:25-35.

[0041] In the above technical solution, the mass of the anhydrous calcium chloride is 4-6% of the total mass of sodium alginate solution, polyvinyl alcohol solution and waterborne polyurethane.

[0042] In the above technical solution, the mass of boric acid is 1-2% of the mass of polyvinyl alcohol.

[0043] The present invention also provides a printed matter comprising, from bottom to top, a black substrate, a coating liquid layer, a special white digital ink layer and a protective layer, wherein the printed matter is formed by printing using the black material high-gloss printing method.

[0044] The black material high-brightness printing method has the advantages that the process is simple, the operation is easy to control, industrialized mass production is facilitated, the printed product has stable quality, has strong tensile resistance, and has good gloss and whiteness, is practical, and has superior comprehensive performance.

[0045] Meanwhile, the printed product comprises, from bottom to top, a black base material, a coating liquid layer, a special number digital ink layer, and a protective layer, the special number digital ink layer is formed by coating the special number digital ink, the protective layer is formed by coating UV glue, and the coating liquid layer is formed by coating the coating liquid. The special number digital ink is used for spraying variable serial numbers, and relevant information of the corresponding product can be inquired through the variable serial numbers. The special number digital ink layer has good gloss and whiteness, and the coating liquid has strong tensile strength, is stable in connection, and is convenient to use. DETAILED DESCRIPTION

[0046] For the convenience of those skilled in the art, the present application will be further described below in combination with examples, and the content mentioned in the embodiments is not a limitation on the present application.

[0047] Example 1

[0048] In this embodiment, a black material high-brightness printing method comprises the following steps:

[0049] S1: Take the black base material and the coating liquid, perform corona treatment on the upper surface of the black base material at room temperature, uniformly coat the coating liquid on the upper surface of the black base material at 100 DEG C, and keep drying at 100 DEG C for 2 s to form a coating liquid layer, and reserve;

[0050] S2: Take the special number digital ink, pressurize and coat the special number digital ink on the upper surface of the coating liquid layer multiple times at 100 DEG C under infrared insulation, keep drying at 100 DEG C for 2 s to form a multi-layer special number digital ink layer, and reserve;

[0051] S3: Coat UV glue on the upper surface of the uppermost layer of the special number digital ink layer at room temperature, and place it under the irradiation of a UV lamp for 2 s to form a protective layer.

[0052] Further, in step S1, the power of the corona is 1100 W.

[0053] Further, in step S2, the pressurized coating is applied in a Carver press with a pressure of 200 kg to press the corresponding thickness.

[0054] Further, the number of layers of the special number digital ink layer is 4.

[0055] Further, in step S3, the condition of the ultraviolet lamp irradiation is that the UV energy is 90j.

[0056] Further, the thickness of the protective layer is 3μm, the thickness of each of the special digital ink layers is 3μm, the thickness of the coating liquid layer is 2μm, and the thickness of the black substrate is 0.1mm.

[0057] Further, the black substrate is a PET film.

[0058] Further, the UV glue is SIEGWERK UV offset matte oil C7.

[0059] Further, the special digital ink comprises the following raw materials in parts by weight: titanium dioxide compound 7 parts, acrylic resin 18 parts, conductive liquid 32 parts, and image oil 8 parts.

[0060] In this embodiment, the acrylic resin is an acrylic resin with brand number 518 of HAN.

[0061] Further, the conductive liquid is a mixture of C12-20 isoparaffin, barium sulfonate, and aryl sulfonate alcohol acid salt in a weight ratio of 8:1:0.6.

[0062] In this embodiment, the barium sulfonate is barium sulfonate with model number T701, the aryl sulfonate alcohol acid salt is dodecyl benzene sulfonic acid isopropyl alcohol amine salt with CAS number 26264-05-1, and the C12-20 isoparaffin is C12-20 isoparaffin with CAS number 64742-46-7.

[0063] Further, the image oil is a mixture of C12-20 isoparaffin and white mineral oil in a weight ratio of 18:1.5.

[0064] Further, the titanium dioxide compound comprises the following raw materials in parts by weight: titanium sulfate 24 parts, illite 32 parts, silica lime 47 parts, and organic silicon treatment agent 7 parts.

[0065] Further, the particle size of the illite is 200-300nm, and the particle size of the silica lime is 300-400nm.

[0066] In this embodiment, the illite is illite from Liaoning Yilong Mining Co., Ltd., wherein the illite contains magnesium oxide 0.2%, aluminum oxide 20.9%, silicon dioxide 17.1%, calcium oxide 0.02%, potassium oxide 3.6%, titanium dioxide 0.3%, water 56.8%, and the balance is impurities. The silica lime is silica lime from Jiangxi Nanfang Sillimanite Co., Ltd.

[0067] Further, the organic silicon treatment agent is mixed by hydroxyl silicone oil and dimethyl silicone oil with a weight ratio of 4.5:3.2.

[0068] In the embodiment, the hydroxyl silicone oil adopts the hydroxyl silicone oil with a CAS number of 70131-67-8. The dimethyl silicone oil adopts the dimethyl silicone oil with a poly energy type of JN-201.

[0069] Further, the preparation method of the titanium dioxide composite includes the following steps:

[0070] E1, hydrolyze titanium sulfate dispersed in deionized water to prepare a titanium sulfate solution with a concentration of 120 g / L for standby;

[0071] E2, mix illite and silica ash uniformly, and then calcine at 900 DEG C to obtain a mixture A;

[0072] E3, after cooling to room temperature, disperse the mixture A in deionized water and treat by ultrasonic for 35 minutes to obtain a slurry A;

[0073] E4, heat the slurry A to 90 DEG C, adjust the pH value to 1.5 with dilute sulfuric acid, and then add the titanium sulfate solution drop by drop into the slurry A, while adding ammonia water to keep the pH value of the slurry A constant at 1.5, stand for 5.5 hours, filter and wash the precipitate with distilled water, and dry at 105 DEG C for 9 hours to obtain a composite material;

[0074] E5, calcine the composite material in a high temperature oven at 900 DEG C for 2 hours to obtain a pre-product;

[0075] E6, disperse the pre-product in deionized water, add an organic silicon treatment agent, stir for 25 min, dry and grind to obtain a titanium dioxide composite.

[0076] Further, the preparation method of the special number code ink includes the following steps:

[0077] A1, mix the conductive liquid and the image oil uniformly to obtain a mixture B;

[0078] A2, add the titanium dioxide composite and the acrylic resin to the mixture B and stir for 2h to obtain a special number code ink.

[0079] Further, the preparation method of the coating liquid includes the following steps:

[0080] B1, dissolve sodium alginate in deionized water and stir uniformly to prepare a sodium alginate solution with a mass fraction of 4%;

[0081] B2, dissolve polyvinyl alcohol in deionized water, and heat at 95℃ for 2 hours until the polyvinyl alcohol is dissolved, then cool the stirred solution to room temperature to prepare a 5% by mass polyvinyl alcohol solution;

[0082] B3, mix the sodium alginate solution, polyvinyl alcohol solution, anhydrous calcium chloride, boric acid, and aqueous polyurethane to obtain a coating liquid.

[0083] Further, in step B3, the solid content of the aqueous polyurethane is 35%.

[0084] In this embodiment, the aqueous polyurethane is PUR-S5718 from Huawei (Guangdong) New Material Technology Co., Ltd. The polyvinyl alcohol is 17-92 from Sinopec.

[0085] Further, in step B3, the weight ratio of the sodium alginate solution, polyvinyl alcohol solution, and aqueous polyurethane is 19:14:32.

[0086] Further, the mass of the anhydrous calcium chloride is 5% of the total mass of the sodium alginate solution, polyvinyl alcohol solution, and aqueous polyurethane.

[0087] Further, the mass of the boric acid is 2% of the mass of the polyvinyl alcohol.

[0088] A printed matter comprising, from bottom to top, a black substrate, a coating liquid layer, a special number digital ink layer, and a protective layer, which is printed by the black material high-light printing method.

[0089] Example 2

[0090] In this embodiment, the special number digital ink comprises the following raw materials in parts by weight: titanium dioxide complex 8 parts, acrylic resin 20 parts, conductive liquid 38 parts, and image oil 8 parts.

[0091] Further, the titanium dioxide complex comprises the following raw materials in parts by weight: titanium sulfate 26 parts, illite 32 parts, silica ash 53 parts, and organosilicon treatment agent 7 parts.

[0092] Further, the organosilicon treatment agent is a mixture of hydroxyl silicone oil and dimethyl silicone oil in a weight ratio of 4.2:3.8.

[0093] The method for preparing the titanium dioxide complex comprises the following steps:

[0094] E1, disperse titanium sulfate in deionized water to hydrolyze and prepare a 150 g / L titanium sulfate solution for standby;

[0095] E2, mix illite and silica ash uniformly, then calcine at 900℃ to obtain a mixture A;

[0096] E3, after being reduced to room temperature, the mixture A is dispersed in deionized water and treated by ultrasonic for 35 minutes to obtain slurry A;

[0097] E4, the slurry A is heated to 90°C, and the pH value is adjusted to 1.5 with dilute sulfuric acid, then the titanium sulfate solution is added dropwise into the slurry A, while adding ammonia water to keep the pH value of the slurry A at 1.5, and after standing for 5.5 hours, the precipitate is filtered and washed with distilled water, and dried at 105°C for 9 hours to obtain a composite material;

[0098] E5, the composite material is calcined in a high temperature oven at 900°C for 2 hours to obtain a pre-product;

[0099] E6, the pre-product is dispersed in deionized water, an organic silicon treatment agent is added, stirred for 25 min, dried, ground, and then a titanium dioxide composite is obtained.

[0100] Further, the preparation method of the special digital ink comprises the following steps:

[0101] A1, the conductive liquid and the image oil are uniformly mixed to obtain a mixture B;

[0102] A2, the titanium dioxide composite and the acrylic resin are added to the mixture B and stirred for 2h to obtain a special digital ink.

[0103] Further, the preparation method of the coating liquid comprises the following steps:

[0104] B1, sodium alginate is dissolved in deionized water and stirred uniformly to prepare a sodium alginate solution with a mass fraction of 4%;

[0105] B2, polyvinyl alcohol is dissolved in deionized water, and after the polyvinyl alcohol is dissolved by heating at 95°C for 2 hours, the stirred solution is cooled to room temperature to prepare a polyvinyl alcohol solution with a mass fraction of 5%;

[0106] B3, the sodium alginate solution, the polyvinyl alcohol solution, anhydrous calcium chloride, boric acid and water-based polyurethane are mixed to obtain a coating liquid.

[0107] Further, in step B3, the weight ratio of the sodium alginate solution, the polyvinyl alcohol solution and the water-based polyurethane is 19:16:35.

[0108] The rest of this embodiment is the same as example 1.

[0109] Comparative Example 1

[0110] The difference between this comparative example and example 1 is that an equal amount of rutile titanium dioxide is used instead of the titanium dioxide composite.

[0111] Further, the rutile titanium dioxide has a particle size of 400-500 nm.

[0112] That is, in the present comparative example, the special digital ink includes the following raw materials by weight: rutile titanium dioxide 7 parts, acrylic resin 18 parts, conductive liquid 32 parts, and image oil 8 parts.

[0113] Further, the preparation method of the special digital ink includes the following steps:

[0114] A1, uniformly mixing the conductive liquid and the image oil to obtain a mixture B;

[0115] A2, adding the rutile titanium dioxide and the acrylic resin into the mixture B and stirring for 2 h to obtain the special digital ink.

[0116] Comparative Example 2

[0117] The present comparative example is different from Example 1 in that the coating liquid is a commercially available Michael DigiPrime model 74433 coating liquid.

[0118] A black material high-brightness printing method, comprising the following steps:

[0119] S1: taking a black substrate and a coating liquid, performing corona treatment on the upper surface of the black substrate at room temperature, then uniformly coating the coating liquid on the upper surface of the black substrate at 100°C, and keeping it dry at 100°C for 2 s to form a coating liquid layer, for standby;

[0120] S2: taking the special digital ink, coating the special digital ink on the upper surface of the coating liquid layer multiple times under infrared insulation at 100°C, keeping it dry at 100°C for 2 s to form a multi-layer special digital ink layer, for standby;

[0121] S3: coating UV glue on the upper surface of the uppermost layer of the special digital ink layer at room temperature, and placing it under the irradiation of a ultraviolet lamp for 2 s to form a protective layer.

[0122] Performance test

[0123] The printed products prepared in Examples 1-2 and Comparative Examples 1-2 were tested for performance. The tensile resistance of the printed product was tested, and the gloss and whiteness of the special digital ink layer were tested. The test data is shown in Table 1 below:

[0124] Table 1

[0125]

[0126] Gloss test: 60° gloss was measured by TOYOSEIKI gloss meter (UD).

[0127] Whiteness value test: measured by whiteness meter.

[0128] Tensile resistance test: according to GB / T 1040.3-2006, the tensile rate is 100 mm / min.

[0129] The above embodiments are the preferred implementation of the present application, in addition to this, the present application can be implemented in other ways, without departing from the concept of the present application, any obvious replacement within the protection scope of the present application.

Claims

1. A method of highlight printing on a black material, characterized by: It comprises the following steps: S1: take black substrate and coating liquid, and perform corona treatment on the upper surface of the black substrate at room temperature, then uniformly coat the coating liquid on the upper surface of the black substrate at a temperature of 80-110 DEG C, and keep the temperature at 80-110 DEG C, dry to form a coating liquid layer, and standby; S2: take special digital ink, and coat the special digital ink on the upper surface of the coating liquid layer for multiple times under infrared insulation at 80-110 DEG C, keep the temperature at 80-110 DEG C, dry to form a multi-layer special digital ink layer, and standby; S3: coat UV glue on the upper surface of the uppermost layer of the special digital ink layer at room temperature, and place it under the irradiation of ultraviolet lamp to form a protective layer; The special digital ink comprises the following raw materials by weight: titanium dioxide compound 7-8 parts, acrylic resin 15-22 parts, conductive liquid 20-45 parts, and image oil 5-10 parts; The preparation method of the coating liquid comprises the following steps: B1, dissolve sodium alginate in deionized water, stir uniformly, and prepare a sodium alginate solution with a mass fraction of 5-6%; B2, dissolve polyvinyl alcohol in deionized water, heat at 90-100 DEG C for 1.5-2.5 hours, and after the polyvinyl alcohol is dissolved, cool the stirred solution to room temperature to prepare a polyvinyl alcohol solution with a mass fraction of 4-6%; B3, mix the sodium alginate solution, the polyvinyl alcohol solution, anhydrous calcium chloride, boric acid and water-based polyurethane to obtain the coating liquid.

2. The method of claim 1, wherein: The conductive liquid is mixed by C12-20 isoparaffin, barium sulfonate and aryl sulfonate alcohol acid salt in a weight ratio of 8-9:1-2:0.5-0.

8.

3. The method of claim 1, wherein: The image oil is mixed by C12-20 isoparaffin and white mineral oil in a weight ratio of 17-19:1-2.

4. The method of claim 1, wherein: Each part of the titanium dioxide compound comprises the following raw materials by weight: titanium sulfate 22-26 parts, illite 30-35 parts, silica ash 45-55 parts, and organic silicon treatment agent 7-8 parts.

5. The method of claim 4, wherein: The particle size of the illite is 200-300 nm.

6. The method of claim 4, wherein: The particle size of the silica ash is 300-400 nm.

7. The method of claim 4, wherein: The organic silicon treatment agent is mixed by hydroxyl silicone oil and dimethyl silicone oil in a weight ratio of 4-5:3-4.

8. The method of claim 1, wherein: The preparation method of the special digital ink comprises the following steps: A1, mix the conductive liquid and the image oil uniformly to obtain a mixture B; A2, add the titanium dioxide compound and the acrylic resin to the mixture B and stir for 1-3 hours to obtain the special digital ink.

9. A printed article, characterized by: The printed matter comprises a black substrate, a coating liquid layer, a special digital ink layer and a protective layer arranged from bottom to top, and is printed by the black material high-brightness printing method according to any one of claims 1-8.

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