The flexo printing machine is mainly composed of four parts, namely the unwinding feeding part, the printing part, the drying part and the rewinding part. In modern flexographic printing presses, there are generally control devices such as tension control, edge control, registration control, printing observation, and mechanical condition monitoring and fault diagnosis systems. In addition, in order to expand the scope of application, some flexographic printing machines are also equipped with glazing, coating, gold plating, cutting, die cutting, drilling, screen printing, gravure printing and other equipment, which has become a joint flexo production line. Unwinding and feeding components: (1) Tension control system; (2) Drive roller; (3) Floating roller; (4) Lateral control system.
(1) Screen roller of flexo printing machine:
1. The type of mesh roller;
2. The parameters that determine the ink transfer performance of the anilox roller are as follows: a, ink dot engraving angle, b, ink hole engraving shape, c, ink hole depth and width d, mesh roller line number and grid line angle, e, ink hole volume ;
3. Mesh roller cleaning: a, chemical solvent brushing method, b method, chemical solvent immersion method, c method, ultrasonic cleaning method, d method, low pressure spray cleaning method, namely plastic microbead spray cleaning method.
(2) Squeegee device
(3) Dry part
(4) Rewind the receiving part
Features of flexo printing machine:
The reason why the flexo printing machine develops at a uniform speed, in addition to the technical breakthrough of printing plates and inks, its own characteristics are also an important reason for attracting users.
1. The structure of the machine is simple, the operation is convenient, the maintenance is convenient, the price of the flexo printing machine with the same function is about 30-50% of the gravure printing machine.
2. The genetic material has strong adaptability, and a good printing effect can be obtained on a plastic film with a thickness of 0.009 mm to 0.25 mm.
3. The embossing force is small, about 19.6~39.2N/cm2, especially the printing materials such as corrugated paper, can't bear too much pressure.
four. The main reason for the low printing cost is the low machine price, low platemaking cost, low paper loss rate during printing, and production cost 30-50% cheaper than gravure printing.
During the use of flexographic printing presses, there are three printing pressures that have a great influence on the printing quality of the product:
Pressure of inking device:
This pressure is the pressure between the inking roller and the metal anilox roller. Its main function is to control the consumption of ink and make the ink transfer evenly.
If the pressure between the two rollers is large, the amount of ink on the metal anilox roller is small; otherwise, the amount of ink is large. At the same time, if the pressure between the two anilox rollers is too small (that is, the gap is too large), once the critical point of the height of the anilox roller is reached, the function of the anilox roller to transfer ink will be lost, causing the printing part of the printing plate to absorb ink Uneven, and the amount of ink is not easy to control during the printing process. Finally, the printed film of the printed matter is too thick, causing ink contamination, poor definition, dot paste, line scattering, and whitish handwriting.
If the pressure of the two rollers is too large (the gap is small), the ink draft on the metal anilox roller is relatively reduced, the dots can be printed clearly, and the writing and lines can be printed clearly and straight, but they lack a certain amount of ink and gloss. At the same time, it is necessary to prevent the two ends of the metal anilox roller and the inking roller from bending, the printer gear jumps, and the excessive pressure between the two rollers causes the teeth to break.
The principle of this printing pressure generally depends on the characteristics of the product. The pressure between the two rollers of the network cable product may be relatively large; the pressure between the small characters may be slightly larger; the pressure between the large characters and the on-site products may be relatively small. At the same time, the pressure is related to the size of the printing area. Generally speaking, if the printing area is larger, the pressure can be lighter to increase the amount of ink, thereby improving the field density, brightness and brightness. Generally speaking, if the printing area is small or delicate, the pressure should be a little larger to reduce the amount of ink and improve the printing clarity. This pressure must be horizontally tangent to the two ends of the anilox roller without deviation, otherwise it will affect the clarity and printing effect of the printed matter.
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