Free-alignment digital printing ceramic and preparation method thereof

Abstract

This invention belongs to the field of architectural ceramics technology and relates to a non-alignment digitally printed ceramic and its preparation method. The preparation method of the non-alignment digitally printed ceramic includes the following steps: applying a neutral base glaze and a color-enhancing base glaze to the surface of a blank according to a design pattern; inkjet printing a pattern of ordinary ceramic ink onto the blank surface after applying the neutral and color-enhancing base glazes; applying a neutral protective glaze to the blank surface after inkjet printing the ordinary ceramic ink pattern; and firing the blank after applying the neutral protective glaze to obtain the non-alignment digitally printed ceramic. This invention eliminates the need for refining the inkjet printing design and adjusting the alignment accuracy between the brick blank, the digital glaze, and the inkjet pattern. By preventing the ceramic ink from emitting a normal color when sprayed at a designated position, the industrialization of non-alignment digitally printed ceramics is achieved.

Description

Technical Field

[0001] This invention belongs to the field of building ceramics technology, and relates to a non-alignment digital printing ceramic and its preparation method. Background Technology

[0002] Ceramics have a long history and have become an indispensable building and decorative material in people's homes. In particular, the rise of ceramic slabs has shown great development potential in the home furnishing industry.

[0003] Digital glaze mold effect ceramic tiles include flat mold effect ceramic tiles and three-dimensional mold effect ceramic tiles. Flat mold effect ceramic tiles have a low-temperature transparent base glaze in some areas and a high-temperature white base glaze in other areas. An inkjet pattern is then overlaid, followed by a protective glaze, achieving overall transparency in specific areas and a high degree of stone imitation. Three-dimensional mold effect ceramic tiles are made by printing a high-temperature white glaze using a digital glaze printer onto a normally glazed body, then overlaying an inkjet pattern and a protective glaze to achieve a three-dimensional mold effect. The normal production of these two types of digital glaze mold effect ceramic tiles requires extremely high alignment precision. Even a slight deviation will result in significant errors; even an error of only 0.5mm will lead to a very poor visual effect and can cause dizziness and eye strain during prolonged viewing. In actual production, the digital glazing machine is subject to a variety of errors, including pressing or cutting size errors, green body shrinkage errors, conveyor belt errors, centering machine errors, inkjet printer installation angle errors, inkjet printer inkjet delay errors, digital glazing machine installation angle errors, digital glazing machine glazing delay errors, and printing errors of inkjet and glazing machine printheads. These errors make it difficult to accurately align the digital glazing mold with the inkjet pattern. Even if the alignment is accurate in a short period of time, the vibration generated by the equipment during operation will gradually amplify these errors as production time progresses. The alignment accuracy must be readjusted after a short period of production, making production extremely difficult and wasting a lot of production time. Therefore, it is still impossible to use digital glazing machines to produce precisely aligned ceramic tile products. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a no-alignment digital printing method for ceramics and its preparation. This method eliminates the need for precise refining of inkjet printing designs and adjusting the alignment accuracy between the brick blank, digital glaze, and inkjet image. By ensuring that the ceramic ink fails to emit its normal color when sprayed at a designated location, the industrialization of no-alignment digital printing ceramics is achieved. Therefore, the no-alignment method of this invention, which eliminates the need for precise alignment, can significantly reduce the production difficulty of digital glaze mold-effect ceramic tiles, greatly improving product production efficiency and yield. To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0005] In a first aspect, the present invention provides a method for preparing alignment-free digitally printed ceramics. The preparation method includes the following steps:

[0006] A neutral base glaze and a color-enhancing base glaze are applied to the surface of the blank according to the design pattern on the plate. The mineral composition of the neutral base glaze includes, by mass percentage: quartz 5%~15%, kaolin 8%~12%, calcined kaolin 5%~10%, calcined alumina 5%~8%, nepheline 20%~35%, dolomite 15%~20%, calcined talc 3%~8%, calcite 3%~10%, calcined zinc oxide 3%~5%, and zirconium silicate 0%~12%.

[0007] Ordinary ceramic ink patterns were printed on the surface of the body after applying a colorless base glaze and a color-enhancing base glaze.

[0008] A colorless protective glaze is applied to the surface of the ceramic body after inkjet printing of a pattern using ordinary ceramic ink. The mineral composition of the colorless protective glaze includes, by mass percentage: 5%~15% quartz, 8%~12% kaolin, 25%~35% potassium feldspar, 15%~25% nepheline, 8%~12% dolomite, 3%~6% calcined talc, 6%~12% calcite, 5%~10% wollastonite, 3%~5% calcined zinc oxide, and 2%~7% barium carbonate.

[0009] The blank after applying a colorless protective glaze is fired to obtain the alignment-free digital printing ceramic.

[0010] The color-developing base glaze is a common base glaze used in ceramic production. Preferably, the chemical composition of the color-developing base glaze includes, by mass percentage: SiO2: 45%~60%, Al2O3: 17%~25%, K2O: 1%~3%, Na2O: 1%~3%, CaO: 2%~5%, MgO: 1%~3%, ZrO2: 6%~12%.

[0011] Preferably, under the synergistic effect of the chromatic base glaze and the chromatic protective glaze, the ceramic ink does not show color when the gray level is below 60%. Particularly preferably, under the synergistic effect of the chromatic base glaze and the chromatic protective glaze, the ceramic ink does not show color when the gray level is below 50%. In other words, the (maximum) chromatic gray level of the ceramic ink under the synergistic effect of the chromatic base glaze and the chromatic protective glaze is 50% or higher (e.g., 50%, 60%, etc.). Specifically, the ceramic ink is coated with red ink and / or coated with yellow ink. Therefore, when the chromatic base glaze and the chromatic protective glaze work synergistically, the overall negative gain effect on the ceramic ink, especially on coated red and coated yellow ink, is 50% or higher.

[0012] Preferably, the colorless base glaze is applied by digital spraying; the specific gravity of the colorless base glaze is 1.5~1.7 g / cm³. 3 .

[0013] Preferably, the color-enhancing base glaze is applied via digital spraying, glazing, or (in a spray booth) spraying; the specific gravity of the color-enhancing base glaze is 1.5~1.7 g / cm³. 3.

[0014] Preferably, the decolorizing protective glaze is applied by spraying or pouring; the specific gravity of the decolorizing protective glaze is 1.4~1.8 g / cm³. 3 Glazing amount is 350~800 g / m 2 .

[0015] Preferably, the grayscale of inkjet printed patterns using ordinary ink is 20% to 50%.

[0016] Preferably, the firing temperature is 1170~1250℃ and the firing time is 40~90 minutes.

[0017] Secondly, the present invention provides alignment-free digital printing ceramics. The alignment-free digital printing ceramics are obtained according to the aforementioned preparation method.

[0018] This invention has the following beneficial effects: it proposes a non-alignment digital printing ceramic and its preparation method, which eliminates the need for precise refining of inkjet printing design drawings and precise alignment between the brick blank, digital glaze printer, and ceramic inkjet printer. By ensuring that the ceramic ink cannot emit normal color when sprayed at a designated position, the industrialization of non-alignment digital printing ceramic is realized. Attached Figure Description

[0019] Figure 1 This is a rendering of the brick surface from Example 1. As can be seen from the image, in the areas where a neutral base glaze is applied, the encapsulated red ink cannot develop its color properly, greatly reducing the difficulty of production alignment. Detailed Implementation

[0020] The present invention will be further described below with reference to the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0021] This invention proposes a non-alignment digitally printed ceramic and its preparation method. The non-alignment digitally printed ceramic comprises, from bottom to top, a body layer, a digital glaze layer (base glaze layer), an ink pattern layer, and a colorless protective glaze layer.

[0022] The purpose of this invention is to allow areas with a color-enhancing base glaze to develop color, while areas with a colorless base glaze remain colorless. Simultaneously, the colorless base glaze is covered with a transparent glaze or mold glaze, while the color-enhancing base glaze is covered with a white high-temperature glaze. Therefore, the colorless areas possess a three-dimensional sculpted or embossed effect. Thus, conventional manufacturing processes require printing transparent or mold glaze in some areas, applying a regular base glaze to others, refining the inkjet print, and ensuring precise alignment between the inkjet print and the brick blank. However, using the colorless base glaze and colorless protective glaze of this invention, regardless of the inkjet printing pattern or the precise positioning of the brick blank, the areas printed with the colorless base glaze remain colorless. Furthermore, both the colorless base glaze and the regular color-enhancing base glaze are printed simultaneously on the brick blank, with a full-coverage colorless protective glaze. In the areas with the colorless base glaze, the combined colorless grayscale reaches 50% or more. In the areas with the regular color-enhancing base glaze, the combined colorless grayscale is only about 20%. Therefore, when the grayscale of the inkjet pattern is between 20% and 50%, the area with ordinary colored base glaze will show color, while the area with neutral base glaze will not. Utilizing this color difference, the inkjet pattern and the brick blank can be arbitrarily aligned, and both will eventually fade in the neutral base glaze area, reducing production difficulty.

[0023] The following is an illustrative example of the preparation method of the alignment-free digitally printed ceramic.

[0024] Preparation of the green body. The green body can be prepared by dry pressing. The chemical composition of the green body is not limited, and commonly used green body formulations in the art can be used. For example, the chemical composition of the green body includes, by mass percentage: SiO2: 62%~67%, Al2O3: 20%~25%, Fe2O3: 0.06%~0.1%, TiO2: 0.1%~0.5%, CaO: 0.1%~0.5%, MgO: 0.1%~1%, K2O: 2%~3%, Na2O: 2.5%~3.5%, and loss on ignition: 4.5%~6.5%.

[0025] Dry the billet. A drying kiln can be used. The drying time can be 0.5 to 1 hour. The moisture content of the dried billet should be controlled within 0.3% to 0.5%.

[0026] A neutral base glaze and a color-enhancing base glaze are applied to the surface of the blank according to the design pattern. In an optional embodiment, the mineral composition of the neutral base glaze includes, by mass percentage: 5%~15% quartz, 8%~12% kaolin, 5%~10% calcined kaolin, 5%~8% calcined alumina, 20%~35% nepheline, 15%~20% dolomite, 3%~8% calcined talc, 3%~10% calcined zinc oxide, and 0%~12% zirconium silicate.

[0027] Preferably, the mineral composition of the colorless base glaze includes, by mass percentage: 5%~15% quartz, 8%~12% kaolin, 5%~10% calcined kaolin, 5%~8% calcined alumina, 25%~35% nepheline, 15%~20% dolomite, 3%~8% calcined talc, 3%~10% calcined zinc oxide, 3%~5% calcined zinc oxide, and 1%~12% zirconium silicate.

[0028] In some embodiments, the chemical composition of the colorless base glaze includes, by mass percentage: SiO2: 35%~48%, Al2O3: 18%~28%, K2O: 1%~3%, Na2O: 3%~6%, CaO: 8%~17%, MgO: 4%~9%, ZnO: 2%~7%, ZrO2: 0~10%.

[0029] The colorless base glaze is applied via digital spraying. A digital spray printer is a novel glazing method; the glaze paste is loaded into the printer, and the glaze is sprayed according to a preset pattern. In an optional embodiment, the specific gravity of the colorless base glaze is 1.5~1.7 g / cm³. 3 If the specific gravity of the neutral base glaze is too low, it will easily run and splatter during digital spray printing, reducing printing accuracy; if the specific gravity of the neutral base glaze is too high, problems such as streaking and nozzle clogging will easily occur during printing.

[0030] The color-developing base glaze can be a high-temperature white base glaze commonly used in the art. In an optional embodiment, the mineral composition of the color-developing base glaze includes, by mass percentage: SiO2: 45%~60%, Al2O3: 17%~25%, K2O: 1%~3%, Na2O: 1%~3%, CaO: 2%~5%, MgO: 1%~3%, ZrO2: 6%~12%.

[0031] It should be understood that any color-developing base glaze formulation that results in a chemical composition falling within the above-described range is applicable to this invention. As an example, the mineral composition of the color-developing base glaze includes, by weight: 35-60 parts potassium feldspar, 10-30 parts sodium feldspar, 3-12 parts kaolin, 5-20 parts calcined clay, 3-10 parts alumina, 5-15 parts quartz, and 8-18 parts zirconium silicate.

[0032] A plain ink pattern is printed on the surface of the blank after applying a neutral base glaze and color development. The texture and color of the plain ink pattern can be adapted as needed.

[0033] A colorless protective glaze is applied to the surface of the blank after inkjet printing a pattern with ordinary ink. In an optional embodiment, the mineral composition of the colorless protective glaze includes, by mass percentage: 5%–15% quartz, 8%–12% kaolinite, 25%–35% potassium feldspar, 15%–25% nepheline, 8%–12% dolomite, 3%–6% calcined talc, 6%–12% calcite, 5%–10% wollastonite, 3%–5% calcined zinc oxide, and 2%–7% barium carbonate.

[0034] For example, the chemical composition of the colorless protective glaze includes, by mass percentage: SiO2: 45%~60%, Al2O3: 12%~19%, K2O: 3%~5%, Na2O: 2%~5%, CaO: 8%~19%, MgO: 2%~6%, ZnO: 2%~7%, BaO: 1%~7%.

[0035] The color-neutralizing protective glaze is applied by spraying or pouring. In an optional embodiment, the specific gravity of the color-neutralizing protective glaze is 1.4~1.8 g / cm³. 3 Glazing amount is 350~800 g / m 2 If the specific gravity of the colorless protective glaze is too low, ink leakage defects are likely to occur after glazing; if the specific gravity of the colorless protective glaze is too high, the glaze slurry flow rate will be too low and the viscosity will be too high, making the glaze slurry prone to clumping.

[0036] Furthermore, if the amount of glaze applied to the base glaze and protective glaze is too low, the glazing effect will be insignificant; if the amount of glaze applied to the base glaze and protective glaze is too high, bubbles will easily appear in the glaze layer, reducing the anti-fouling performance of the glaze surface.

[0037] By utilizing the influence of different raw materials in the glaze on the color development of coated red and coated yellow inks, a colorless base glaze and a colorless protective glaze with negative color gain for ceramic inks, especially coated red and coated yellow inks, were developed. The colorless base glaze is sprayed onto designated areas of the brick using a digital inkjet printer, followed by inkjet printing and then the colorless protective glaze. During the high-temperature firing stage, specific elements in the glaze react physically or chemically with the chemical components in the ink, weakening the color development ability of the coated red and coated yellow ceramic inks to a level imperceptible to the naked eye. This causes the textures that should be precisely aligned to appear naturally at the designated locations. This technology eliminates the need for precise inkjet design drawings and precise alignment between the brick, digital inkjet printer, and ceramic inkjet printer, greatly reducing the production difficulty of digital inkjet mold-effect ceramic tiles and significantly improving production efficiency and yield.

[0038] The principle behind the negative gain in color development of encapsulated red and yellow inks: Encapsulated pigments are zircon-encapsulated colorants. The zircon lattice protects the colorant, ensuring its stability during high-temperature firing. Generally, red and yellow pigments are not heat-resistant, often resulting in color fading or even loss of color during high-temperature firing. Therefore, zircon encapsulation is necessary for protection during high-temperature firing. However, zircon is easily melted in glazes with high calcium and magnesium content. When the zircon melts, the colorant protected within its lattice also melts, destroying its color-developing structure. Therefore, glazes with high calcium and magnesium content exhibit a "color absorption" phenomenon. This invention utilizes this "color absorption" defect to develop alignment-free digital printing ceramic tiles.

[0039] In particular, the digital glazing process involves spraying glaze onto the brick blank according to a preset pattern. Areas with a neutral base glaze are then covered with a neutral protective glaze. The encapsulated red and yellow inks in this glaze cannot be displayed when the grayscale of the inkjet pattern is below 50%. In areas without a neutral base glaze, the encapsulated red and yellow inks cannot be displayed when the grayscale of the inkjet pattern is below 20%, but can be displayed when the grayscale is above 20%. This leads to a method where a digital glazing printer prints a standard or neutral base glaze according to a preset pattern, then prints an inkjet pattern. The encapsulated red and yellow inks in the inkjet pattern have a grayscale between 20% and 50%. After applying a neutral protective glaze and firing, the resulting product will show no display of the encapsulated red and yellow inks in the neutral base glaze areas, while the colored base glaze areas will display normally. This achieves a visually precise alignment even if there are misalignments between the brick blank, the digital glaze, and the inkjet pattern during production.

[0040] The blank after applying a colorless protective glaze is fired to obtain a digitally printed ceramic that does not require alignment. In an optional embodiment, the firing temperature is 1170~1250℃ and the firing time is 40~90 minutes.

[0041] Compared with the prior art, the present invention has the following beneficial effects: it eliminates the need for detailed production design drawings and precise alignment between the brick blank, digital glaze printer, and ceramic inkjet printer, greatly reducing the production difficulty of digital glaze mold effect ceramic bricks, significantly improving product production efficiency and the rate of excellence, and enhancing the visual effect of digitally printed glaze ceramic bricks (slabs).

[0042] Examples 1-5

[0043] The preparation method of alignment-free digitally printed ceramics includes the following steps:

[0044] Step 1. Apply a neutral base glaze and a color-enhancing base glaze to the surface of the blank according to the design pattern. The neutral base glaze is applied by digital spraying. The specific gravity of the neutral base glaze is 1.6 g / cm³. 3 The color-enhancing base glaze is applied via digital spraying. The specific gravity of the color-enhancing base glaze is 1.6 g / cm³.3 .

[0045] Step 2. Inkjet print ordinary ceramic ink onto the surface of the body after applying the neutral and colored base glazes.

[0046] Step 3. Apply a colorless protective glaze to the surface of the ceramic blank after inkjet printing with ordinary ceramic ink. The colorless protective glaze is applied by spraying. The specific gravity of the colorless protective glaze is 1.6 g / cm³. 3 Glazing amount is 700 g / m 2 .

[0047] Step 4. Fire the blank after applying the colorless protective glaze to obtain alignment-free digital printing ceramic. The firing temperature is 1200℃ and the firing time is 65 minutes.

[0048] The formulations of the colorless base glaze and colorless protective glaze used in Examples 1-5 are shown in Table 1.

[0049] Table 1

[0050]

[0051] In Table 1, the achromatic gray level refers to the highest gray level at which the ink does not show color.

[0052] Comparative Examples 1-5

[0053] The process is basically the same as the previous example, except that the formulas for the colorless base glaze and the colorless protective glaze are changed.

[0054] Comparative Example 6

[0055] The process is essentially the same as the previous example, except that no color-reducing base glaze is applied. That is, only a color-enhancing base glaze is applied to the surface of the blank according to the design pattern.

[0056] The formulations of the base glaze and protective glaze used in Comparative Examples 1-6 are shown in Table 2.

[0057] Table 2

[0058]

[0059] In the embodiments and comparative examples, the chemical composition of the color-developing base glaze includes, by mass percentage: SiO2: 55%, Al2O3: 22%, K2O: 2%, Na2O: 3%, CaO: 5%, MgO: 2%, ZrO2: 11%.

[0060] The following analysis and explanation are based on the above embodiments, comparative examples, and test results:

[0061] 1. Analysis of the experimental results of the digital printing base glaze and digital printing protective glaze in Examples 1-5 shows that the digital printing base glaze and digital printing protective glaze prepared in Examples 1-5 have a better negative gain effect on encapsulating red and yellow inks, with the average grayscale of the achromatic inks all above 50%. It can be seen that if the grayscale of the encapsulated red and yellow inks in the inkjet print is below 50%, then the color development in this area is not visible to the naked eye.

[0062] 2. Compared with Example 1, the quartz content in the base glaze of Comparative Example 1 was higher than the specified range, while the content of calcined kaolin and dolomite was lower than the specified range. This resulted in over-firing of the base glaze, leading to numerous open bubbles on the glaze surface. In contrast, the quartz and dolomite content in the protective glaze of Comparative Example 1 was lower than the specified range, while the content of nepheline and calcined zinc oxide was higher than the specified range. This resulted in an excessively high coefficient of thermal expansion of the glaze, causing cracks to appear on the glaze surface.

[0063] 3. Compared with Example 2, the quartz and calcite content of the base glaze in Comparative Example 2 is lower than the specified range, and the glaze surface has no obvious defects, but the negative gain effect on encapsulating yellow ink is low, making it difficult to apply to the alignment-free digital printing glaze technology; the quartz and potassium feldspar content of the protective glaze in Comparative Example 2 is higher than the specified range, and the nepheline and calcite content is lower than the specified range, resulting in a higher high-temperature viscosity of the glaze and causing the glaze surface to exhibit orange peel wrinkling.

[0064] 4. Compared with Example 3, the calcined kaolin and zirconium silicate content of the base glaze in Comparative Example 3 is higher than the specified range, while the nepheline and calcined zinc oxide content is lower than the specified range, resulting in under-firing of the glaze and many high-temperature bubbles on the glaze surface; the kaolin and calcined talc content of the protective glaze in Comparative Example 3 is lower than the specified range, while the dolomite and wollastonite content is higher than the specified range. The glaze surface has no obvious defects, but the negative gain effect on the color development of red and yellow inks is low, making it difficult to apply to the alignment-free digital printing glaze technology.

[0065] 5. Compared with Example 4, the kaolin content in the base glaze of Comparative Example 4 was lower than the specified range, while the dolomite content was higher than the specified range, resulting in more glaze blemishes and easy glaze slurry sedimentation; the kaolin and barium carbonate content in the protective glaze of Comparative Example 4 was higher than the specified range, while the wollastonite and calcined zinc oxide content was lower than the specified range, resulting in poor glaze slurry suspension, easy thixotropy, and poor overall color development.

[0066] 6. Compared with Example 5, the kaolin and calcite content in the base glaze of Comparative Example 5 is higher than the specified range, while the calcined talc content is lower than the specified range, resulting in poor suspension of the glaze, easy thixotropy, and overall transparency, which is not suitable for ceramic base glazes; the potassium feldspar and barium carbonate content in the protective glaze of Comparative Example 5 is lower than the specified range, while the calcined talc and calcite content is higher than the specified range, resulting in lower high-temperature viscosity of the glaze and pinhole defects on the glaze surface.

[0067] 7. Compared with Example 5, the base glaze in Comparative Example 6 was a common production base glaze, and the protective glaze was a colorless protective glaze within the specified range. Neither the top glaze nor the protective glaze had obvious production defects, but the negative gain effect on the color development of the encapsulated red and yellow inks was limited, indicating that the colorless protective glaze can be applied to a common production base glaze and can develop normal color. The obvious negative gain effect only appears when it is applied over a colorless base glaze.

[0068] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing alignment-free digitally printed ceramics, characterized in that, The preparation method includes the following steps: A neutral base glaze and a color-enhancing base glaze are applied to the surface of the blank according to the design pattern. The mineral composition of the neutral base glaze consists of the following raw materials by mass percentage: quartz 5%~15%, kaolin 8%~12%, calcined kaolin 5%~10%, calcined alumina 5%~8%, nepheline 20%~35%, dolomite 15%~20%, calcined talc 3%~8%, calcite 3%~10%, calcined zinc oxide 3%~5%, and zirconium silicate 0%~12%. The chemical composition of the color-enhancing base glaze includes, by mass percentage: SiO2: 45%~60%, Al2O3: 17%~25%, K2O: 1%~3%, Na2O: 1%~3%, CaO: 2%~5%, MgO: 1%~3%, and ZrO2: 6%~12%. The specific gravity of the neutral base glaze is 1.5~1.7 g / cm³. 3 ; Ordinary ceramic ink patterns are inkjet printed on the surface of the body after applying a colorless base glaze and a color-enhancing base glaze; wherein, the grayscale of the inkjet printed ordinary ceramic ink patterns is 20%~50%; the ordinary ceramic ink used for inkjet printing ordinary ceramic ink patterns is encapsulated red ink and / or encapsulated yellow ink. A colorless protective glaze is applied to the surface of the ceramic body after inkjet printing of a pattern using ordinary ceramic ink. The mineral composition of the colorless protective glaze consists of the following raw materials by mass percentage: quartz 5%–15%, kaolin 8%–12%, potassium feldspar 25%–35%, nepheline 15%–25%, dolomite 8%–12%, calcined talc 3%–6%, calcite 6%–12%, wollastonite 5%–10%, calcined zinc oxide 3%–5%, and barium carbonate 2%–7%. The specific gravity of the colorless protective glaze is 1.4–1.8 g / cm³. 3 Glazing amount is 350~800 g / m 2 ; The blank after applying the colorless protective glaze is fired to obtain the alignment-free digital printing ceramic; under the synergistic effect of the colorless base glaze and the colorless protective glaze, the ordinary ceramic ink used for inkjet printing ordinary ceramic ink patterns does not show color when the gray level is below 50%.

2. The preparation method according to claim 1, characterized in that, The colorless base glaze is applied by digital spraying.

3. The preparation method according to claim 1, characterized in that, The color-enhancing base glaze is applied via digital spraying, glazing, or spray booth spraying; the specific gravity of the color-enhancing base glaze is 1.5~1.7 g / cm³. 3 .

4. The preparation method according to claim 1, characterized in that, The decolorizing protective glaze is applied by spraying or pouring.

5. The preparation method according to claim 1, characterized in that, The firing temperature is 1170~1250℃, and the firing time is 40~90 minutes.

6. Alignment-free digitally printed ceramics, characterized in that, The alignment-free digitally printed ceramic is obtained by the preparation method according to any one of claims 1 to 5.

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