Ceramic printing (c)

(III) Ceramic Glaze Applique Paper Screen Printing Process

The silk screen ceramic ink is printed on the PVB film through the screen printing plate to form an image, which is pasted on the ceramic vessel, and after roasting, presents a bright color, which is the screen ceramic glaze on the decal process. Wire mesh ceramic glaze decal paper has two printing methods: "full silk screen" and "flat silk". One to three sets of full silk screen printing can represent a complete screen image. Some screens need more typographic printing for flat printing, and silk screen printing can achieve ideal results.

Applique decals can be divided into transfer decals and decals

The difference between the two is that the decorative pattern of the former type of flower paper faces the porcelain when it is decaled. The following issues should be noted in the decal paper printing process:

1 plate making. For original design, photo color separation, and special color materials, try to avoid color reset (superimposed colors) and use color juxtaposition.

2 The method of flat wire bonding can be used to reduce the overlapping thickness of the ink layer, but the silk screen must be printed after printing first, which can reduce the burst of flowers and avoid the appearance of moiré.

3 When stacking is necessary, besides taking into account the chemical reactions between the kiln and the kiln, it is also necessary to consider balancing the color temperature between the screen printing porcelain inks as much as possible so that the active dots are stacked and the color is burned when the colors are stacked. The low temperature of the coloring is printed below, and the high temperature is superimposed on it. This is because during the process of burning colorful flowers, when the low-temperature silk screened porcelain ink layer starts to evaporate and evaporate, the high temperature silk screened porcelain ink layer laminated on it still has unmelted particle gaps, allowing the silk screen printing ink layer below to be printed. Molten gas passes to avoid popping flowers. At the same time should also pay attention to the following points:

a. The printing color sequence is different, the diffuse reflection and refraction produced after overprinting are different, and the color rendering effect after overprinting and burning is also different. According to the characteristics of originals and customer requirements, a reasonable arrangement of color sequence is required to obtain a rich and colorful ideal. product.

b. Because the decals themselves cannot be viewed directly with a color effect, only after high-temperature roasting, a series of changes occur in the ceramic pigments infiltrating into the glaze layer and the glaze to achieve the purpose of coloration. Therefore, the screen angle is 90° in yellow, 75° in red, 15° in blue, and 45° in black. The color sequence of printing is shallow and deep, that is, yellow (Y), magenta (M), and blue (C). ), The last ink (Bk).

c. Small areas of text or lines are printed first. Large areas of ink are printed on the back to prevent large areas from being scratched or dirty.

d. Overprint the printed lines on the top of the screen after printing. This layered layered layer has a strong sense of three-dimensionality and space.

4 glaze porcelain ink. The main component of the linking material is polymethyl acetate, the solvent is usually alkylated turpentine, and the ink auxiliaries mainly include paraffin wax, dry oil, leveling agent (make the squeegee pass through the screen), and wetting agent (permeate). , stabilizers, curing agents, etc.

The binders and auxiliaries are used in equal amounts. The ratio of the binder to the pigment is 10 parts of pigment and 5 parts of binder.

5 choice of wire mesh. Mainly yellow and magenta nylon mesh. Use less stainless steel mesh. Ordinary products with 270-320 mesh screen, a unit of flower surface requires a relief effect when using 220-250 mesh, fine text products with 340-400 mesh. The number of screen lines and screen mesh is basically 1:3.

6 When screen-printing decals, the screens must be completely stretched on the frame. The hardness, viscosity, and drying conditions of the ink must be compatible with the decals used, and the angles of the press and the squeegee must be carefully adjusted.

First, a standard color mark was scraped with silk screened porcelain ink. Then use a variety of screen printing on the flower paper to observe printability, drying time and dryness. It is then affixed to a pan, placed in a kiln, and fired at 700-800°C. The colors of the color dial and the original are fully considered, and the thickness of the screen mesh is determined in consideration of the blending of the shades of the glaze, the density, the ink thickness, the line thickness, the size of the dot, and whether or not the floor is covered.

If the ink is dried too fast during printing, hole blocking will occur. On the contrary, if the drying is too slow, slurry will be produced on the printing surface. The color order of the printed sheets is from light to dark. Finally, the pattern is covered with an acrylic resin and then dried.

7 on the film. The upper membrane can be divided into two stages: membrane and membrane.

a. Film-forming ratio: Polyvinyl butyral resin: Methanol (ethanol) = 1:5. Butyral should be selected around 16-18s. First, methanol (ethanol) is pumped into the reaction vessel according to the amount, and the butyral is charged under the stirring condition. The heating switch is turned on (the temperature is controlled at 50-60° C.) and stirred for 3 hours. After the butyral is completely dissolved, the material can be discharged. In standby, the membrane material should be completely dissolved, no block, no impurities should be slightly concentrated, and methanol (ethanol) can be added to the membrane to adjust the concentration.

b.Membrane: The special bottom paper for paper decals (sizing paper) is first applied to the paper cutter to repair the four sides to ensure that the specification size is up to standard.

Special filming machine is chosen for the equipment (the principle is similar to glazing). Adjust the gap between the good roll and the print roll so that the film is evenly coated on the base paper. General requirements on the second (do not have to turn head), the first time you can dry on the second time (every time you want to pull open paper, fan cooling) film thickness standard is 0.01mm ± 0.0001mm, can be thick can not be thin , can be adjusted by measuring with a micrometer.

Film on the drying tunnel should be maintained between 70-80 °C, the temperature is too high, the bottom paper scorched, too low will be blistering, dry impermeability, the formation of adhesions. All in all, the film requires bright, uniform thickness, uniform, no residual film residual pulp, no adhesion, no damage. The dry paper can be stacked neatly and protected from dust. Generally, it is best to store the film for 15-20 days (flattening and shaping).

(4) Characteristics of Flat Wire Combined Printing Process

1. Features of flat wire combined with printing process (1) Good reproducibility of lithographic printing screens Since the dots are relatively fine, the halftone screens are closer to the continuous tone screen, the finer representation of fine screens, and the finer levels of reproduction. Reproduction is good.
(2) Features of the screen printing method for reproducing the picture The ink layer is thick and colorful, and the texture of the picture is close to the scene. The bright and dark contrast of the printing ink and the matting ink makes the picture more three-dimensional.

2. Flat wire bonding process implementation method |

(1)Different locations are used to analyze the picture first. Taking the landscape painting as an example, the location of the distant mountains, sky, clouds, fog, and subtle changes in levels can be reproduced by means of plain printing, for deeper changes in the large-scale field or level. Parts, as well as trees, grasses, stones, etc. with a close-up texture, can be represented by screen printing plates.

(2) The screen level firstly analyzes the characteristics of the typographic and silk screen reproduction. The tone reproduction curve of the print screen is drawn based on the characteristic curve of the photosensitive material and the reproduced curve of the printing ink tone. The abscissa is the original density, and the ordinate is the print density. Take the equivalent neutral grey or black version as an example, as shown in Figure 4-8.

The standard original contrast value is 2.0, some can reach 3.0, but the offset printing ink can only reach 1.6 or so. At the same time, the latitude and tone of the flattening screen determine that the plain printing screen is shallow and flat. The density of screen ink can reach 2.6-3.0, even up to 3.5, but due to the mesh size and the ink, the printing process characteristics determine the screen printing tone is generally 15% -85%, the screen level and level, as shown 4-9 shows. This results in the loss of some of the brighter tone levels and darker tone levels.

According to the above characteristics, in the combination of flat-wires and plate-making, it is necessary to combine the characteristics of each, and use the flat-printing to reproduce the bright-toned part of the screen to ensure the brightness of the tone, and reproduce the dark tone with screen printing, so that the picture has a deeper density and can approach or exceed the transmission manuscript. When the two processes are used together, care must be taken to make the picture hierarchy to be continuous and to avoid improper convergence (see Figure 4-10).

(3) Flat wire combined layout requirements Prefabricated crosshairs (+), angles (┘), and tangents are required according to the size and size of the prints. In the gauge line, the mark position and the direction of paper feeding can be marked. When printing, pay attention to the position of the printer and the screen on the printing and screen printing machines.