Fine Screening Technology Development of Ceramic Screen Printing

Decorative patterns on ceramics have long been used in blown, hand-painted, rubber-stamped, and copper plated and offset decals. In recent years, with the application of screen printing in the ceramic industry, decorative patterns on ceramics are more three-dimensional. After firing, the enamel is thick and very bright, and looks as if it was painted with a enamel paint. The pattern is much finer than the one using the blown spray method, and the production efficiency is also improved a lot. Since the screen printing has many advantages as described above for the decoration of ceramics, its application range is wider day by day.
First, the development of ceramic screen printing Since the realization of industrial production of ceramic vessels so far, there have been three major changes in the decorative technology. In the 1920s, a decorative process combining lithographs and artificial brushing was realized. Instead of the hand-carved version, the products were refined and the quality was greatly improved. However, the production efficiency was still very low. Only 600 to 800 sheets were produced per person per hour. Moreover, there is dust pollution. At the end of the 50's, an automatic squeegee appeared, producing 4,000 to 5,000 pieces per hour, improving the efficiency of squeegeeing.
The newly emerged contradiction is that printing and squeegee speeds are incommensurate and have been improved several times. By the mid-1960s, lithographically printed decals were finally replaced by offset printing, which increased the degree of automation and enabled the two processes of printing and swarfing to be supported by Jackie Chan. A new mechanized production process, mainly offset printing, is another major change in the production of ceramic decals.
Screen printing ceramic decal paper, simple operation, strong adaptability, thick ink layer. Therefore, rapid development. The 50's began to be automated, and at the same time, process technology, screen Printing Materials, etc. have all achieved amazing development. According to statistics, in the 1960s, silk screen decals accounted for about 20% of the total decals. In the 1970s, they increased to more than 85%. Almost 100% of glass decals were screen printed. At the same time, we started using various special screen printers. Printing decoration directly on the utensils, both quality and scale have also reached a very high level. At present, silk-screened ceramic decals basically replace offset-printed ceramic decals and become the main decorative means of ceramic vessels with high output, high efficiency, low cost, and strong artistic appeal.
The reader is introduced to the latest progress of some silk screen ceramic decals technology.
1 Capillary adsorption type photosensitive film. This kind of photosensitive film is a plate-making material newly developed in the 70's. Using this photosensitive film plate, it is only necessary to wet the film surface with water, and it can be firmly attached to the surface of the screen, and then cured by exposure to the Internet. The main components of this kind of photosensitive film are polyvinyl alcohol and diazonium salt, and the printing capacity is 30,000 impressions. Due to the fine prints and the simple plate making operation, higher grade products can be printed.
2 Thermal printing inks. Traditional inks fall into two categories: one is a volatile drying ink; the other is an oxidation-drying ink, and these two types of ink are commonly referred to as cold printing inks. Oxidation-drying inks have a long drying time; volatile drying inks need to be heated to dry, waste energy, and have the problem of solvent evaporation, pollution of the environment, and fire and other safety problems.
The thermal printing inks developed in recent years are prepared from ceramic pigments or noble metal preparations and thermoplastic resins. The main raw materials are methacrylate polymers or waxes, free of free monomers, and low softening temperature, generally around 50°C. The ink has a good fluidity and can be printed on a heat-resistant screen plate, but it is usually used for direct ceramics.
The printing performance and transfer performance of these inks are better than those of cold printing inks. Since no solvent is used, the pigment ratio in the ink is relatively increased, and the ink layer has strong hiding power, which is very suitable for glass decoration. Past color pigments that are not commonly used in the past can also be used. After printing, the imprints quickly radiate and freeze and solidify, making it easy to overprint and not easily contaminate the dirty stains.
In the 1970s, it was able to achieve rapid, multi-color mesh ceramic screen printing, mainly due to the development and utilization of thermal printing inks.
3 tricolor printing ceramic pigments. The use of three primary colors of yellow, magenta, and cyan to print color art works is a very mature process technology in offset printing. However, for a long time, it has been difficult to use the principle of three primary colors to print silk-screened ceramic decals. The main reason is that ceramic pigments are colored at high temperatures, and some of the pigments will react at high temperatures, causing the color to change.
In recent years, on the basis of the serialization, specialization, and increase of the stability of ceramic pigments, three kinds of blending pigments of cyan, magenta, and yellow have been developed, and the coloration basically meets the chromatographic requirements. The transfer decals printed with these three basic colors can exhibit a multi-color effect after firing. The disadvantage is that the red color is not clear enough, and the black color is insufficient. It is necessary to make up the black and red colors to enhance the firing effect.
At present, although the primary colors of ceramic pigments are still not ideal, they have completely broken through the traditional concepts. Further improvement of this topic will have a greater impact on ceramic decoration.
4 Superfine mesh modulation technology. For a long time, the production of offset-printed ceramic decals can duplicate richly-acclaimed art works, while screen-printing can only print lines or ink sticks, making it difficult to reflect the level of works. In recent years, due to the development of photographic technology, the continuous improvement of screen-making and screen-making technology and its theory, especially the development and utilization of high-quality fine screens, high-resolution photographic materials, and ultra-fine ceramic pigments, are used for the preparation of screenings. Wire mesh screen provides favorable conditions.
The direct screen ceramic screened screens can be printed directly on ceramic and glassware. The screen printing decals are manufactured on the basis of 133 lines and 155 lines. Some manufacturers have The use of ultra-fine screen-screening and plate-making, its exquisite reproductions are almost the same as continuous-tone works.
5 Heat transfer decal technology. The earliest transfer decals needed to be attached to the ceramic surface with adhesive during transfer. In the 30's, it was changed to the water paste method, also called the cold transfer method. The structure of the cold transfer decal paper is to apply water-soluble adhesive on the paper base and print the pattern on the plastic surface, and then print a layer of water-insoluble resin film as a transfer carrier, and decal the decal paper into the water when decaling, 30 Seconds later, the water-soluble glue can be used to slide the picture off the paper base, and the picture can be attached to the porcelain surface by its adhesiveness.
In the early 1970s, successful thermal transfer decals were studied. The structure was that the water-based adhesive was not used between the paper base and the picture, but wax or hot melt resin was used. When decaling, the vessel is first preheated to 120-150°C, mechanically driven, automatically positioned, and then the image on the thermal transfer ceramic decal paper is fixed to the decal position with a decal applicator. The surface temperature of the vessel softens the floral film. The picture is firmly attached to the porcelain surface, and at the same time, the wax on the paper base can be melted to separate the paper base from the picture.
The use of heat decal technology can directly decorate bisque porcelain and white porcelain (porcelain after firing), after the decals can directly enter the kiln, and the porcelain surface is clean. The success of heat decals was a major breakthrough in the transition from manual decals to mechanical decals. At present, except for a small amount of manual decals, developed countries mainly use mechanical decals, while developing countries still rely mainly on manual decals.