First, the flexographic printing process

Flexographic printing refers to a relief plate made of a flexible material such as rubber or resin, and a process for transferring ink for printing by an anilox roller on a machine. In the early stage of flexographic printing, due to the use of flexographic printing inks, there is also a common name for flexographic printing. Since the flexographic process has the commonality of embossing, lithography and gravure printing, it has a wide adaptability to the characteristics of the substrate, simple structure and high precision. The machine is mainly composed of four parts: an ink receiving roller, an anilox roller, a plate cylinder and an impression cylinder. The flexographic printing structure is arranged in a three-roller type, a stacked type (ie, a roll type), an array type, and a satellite type. The three-roller type is composed of a multi-color single group, each single-group structure has only three rollers, and a squeegee is arranged on the metal anilox roller to adjust the amount of ink. Since the squeegee is in contact with the metal anilox roller, the texture is easily damaged. Roller, which is a structural defect. The cascading flexographic printing press stacks the individual monochrome units on both sides of the main unit for printing, and each monochrome unit is driven by the main gear chain. When the machine roll paper passes through the printing portion, it can be printed on the front and back sides, and the ink is dried before the reverse side printing. Another advantage of this machine is that when adjusting or repairing the components of the monochrome unit and washing the color, other units are not affected, and the production can be continued without stopping the machine, and the equipment utilization rate is high. However, the overprinting accuracy of the machine is almost inferior to that of the satellite type, and it is not suitable to print a substrate with large elasticity and thin material. The arranging flexographic printing machine is composed of a multi-color single group, and the paper running between each color group is in a flat state, so that the tension can be kept relatively balanced, so it is suitable for printing thin paper and thick paper products. The structure of the satellite flexographic printing press is such that there is an impression cylinder on the main frame, and various color plate cylinders are arranged around it. The advantage of this type of machine is that the overprinting is accurate and it is more suitable for printing substrates with high flexibility.

Second, pearl printing process

Pearlescent printing refers to special printing techniques using pearlescent inks. Because the pearlescent ink has the natural luster of the beaded pearl, the printed printed matter is like a jewel-like color, which is noble and elegant. The pearl printing process can be lithographic, letterpress, gravure or flexographic printing, or screen printing. Due to the different printing methods, it is reasonable to select pearlescent inks with different particle size ranges according to the characteristics of the process. For example, the letterpress process may use a pearlescent pigment with a coarse particle size. The flat printing process should use a fine pearlescent ink. The screen process should be larger than the mesh size of the pearlescent pigment. Pearlescent printing can directly add pearl powder to the ink, but it should be used immediately to prevent the pearl powder from sticking to each other due to precipitation, which affects the use effect. The blending amount of pearl powder and printing ink is about 10.20%. For printing pearlescent inks using a flexographic process, an anilox roll of 30 lines/cm should be used to ensure that the pearlescent pigment is fully and evenly transferred to the printing surface. The pearlescent ink is printed by a gravure process. It is advisable to use a network cable of 30 to 40 lines/cm, and the corrosion depth is controlled to 35 to 40 rfl, so that the ink pigment can obtain a good transfer effect.

Pearlescent printing substrates have good surface gloss properties, high smoothness and best printing results, such as glass cardboard, coated paper, calendered white paper and plastic film.

Third, the fragrance ink printing process

In daily life, we can see prints of aromatic scent that can be emitted, such as business cards, greeting cards, and packaging products, which are printed with fragrance inks. This process can be used to directly add perfume to the ink and print it with embossing, flexographic and offset presses. The method is simple, but the fragrance is difficult to preserve.

Printing with perfume inks sealed in capsules is now widely used. This type of printing is because the fragrance is rubbed and broken by the microcapsules and slowly emits an aromatic flavor, which can be preserved for a long time. The use of perfume inks is printed by screen printing. Because the amount of printing ink is too large to dry, the drying problem of the ink should be considered. The amount of ink should be less appropriate. It is advisable to use the ink area of 30% mesh to avoid being too thick due to the full version. Fragrant. Products printed with perfume inks should be protected from heavy pressure and folding. The fragrance inks have various flavors such as flowers, fruits and cheeses, and can be appropriately selected according to the characteristics of the products and the requirements of the customers. Perfume inks are not only suitable for paper printing, but also for printing on plastics, fabrics and wood.

Fourth, color printing process

The ink used in color-changing printing can change color with changes in temperature. This ink, also known as temperature-sensitive ink, usually uses the change in ink color to display the temperature of an object or environment. The discoloration of the ink lies in the discoloration mechanism of the pigment. The color change mechanism of pigments mainly includes crystal transfer type, thermal decomposition type and crystal structure change type. The crystal transfer type changes color by transferring the pigment crystal form due to heat, and returns to the original crystal and color after cooling. This is a reversible color changing ink. The pigment which is decomposed by thermal decomposition is discolored by releasing gas after chemical decomposition reaction due to heat, and does not return to its original color after cooling. This is called irreversible high-temperature discoloration ink. The crystal structure change type pigment can be discolored by the loss of crystal water due to heat, and is not immediately reduced after cooling, but in the case of moist moisture, crystals are slowly formed to restore the original color, which is a reversible low temperature color changing ink. The color change mechanism of the color changing ink is related to the pigment characteristics, and the variety and performance of the filler, the binder and the solvent in the ink also directly affect the discoloration of the color changing ink. Color-changing inks are mainly used for over-temperature notices, body temperature color block cards touched by human hands, postcards, weather forecast prints, high-temperature indicator prints for boilers, anti-counterfeit trademarks, and surface temperature measurement of aviation equipment. Most of the color-changing inks are screen printed, and can also be printed by offset and gravure processes.

Five, foam printing process

The term "foaming printing" refers to a printing method in which a microsphere foaming ink is screen printed on a paper or a crepe and then heated to form a embossed embossed graphic or Braille reading. Since the image of the foam printing can be embossed, the microsphere foaming ink is used. The ink is made of a high molecular polymer monomer and is made into a hollow micrometer having a diameter of 5 m to 80 m and a low boiling point solvent. The plastic sphere, when the microsphere is heated, the low boiling point solvent in the sphere is heated and vaporized, so that the diameter of the microsphere is rapidly increased to 5 to 30 times of the original sphere, so that the surface of the substrate forms an embossed graphic. Microsphere foam printing is widely used in new braille printing technology systems. The Braille printing system differs from the original Braille printing method in that it uses a computer. The dots are printed with a foaming ink, and after heating, the braille is raised. Therefore, not only can it be printed in a large amount quickly, but also printing can be performed on both sides of the paper, and the pattern can be printed.

Six, decal printing process

Decal printing is achieved by indirect transfer. First, the pattern is printed on the adhesive paper or plastic film by a lithographic process, and then the finished product of the decal is attached to the surface of the object to be decorated, and the water is dissolved by using water, and the gum is dissolved by water soaking, and then the paper or paper is dissolved. The plastic film is peeled off and the image is transferred to the surface of the object. The main processes of the decal printing process are: crepe paper, plate making, printing, transfer and post-processing. The crepe paper process consists of two manual and mechanical crepe paper methods. The manual crepe paper process is simple and does not require special equipment, but the quality of enamel is difficult to control, so it is only suitable for small batch production. Mechanical crepe paper is made of special coating equipment and is suitable for mass production. The plate-making method of decal printing adopts the lithographic plate making method, and the graphic produced by the printing is in the positive direction. After printing on the “crepe paper”, the graphic is reverse-shaped, and after being attached to the decorative object, it becomes positive. To the graphic structure. Before decal printing, first print a transparent varnish on the decal. When printing, the color with strong transparency should be printed first, and the color with strong opacity should be printed. After the transfer, the same graphic image as the ordinary printing color sequence can be obtained.