Corrugated carton flexo technology (middle)

Second, the thin version of the cushioning technology 1, thin version of the padding technology is usually non-uniform corrugated substrate thickness, the pressure is too light, may make the ink transfer uneven, easy to cause the printed parts of the site white, or corrugated plate shape; and pressure If it is too heavy, it will cause the deformation of the substrate and the enlargement of the dots, affecting the fine lines and dot overprinting, and also cause the corrugated box strength to be severely damaged.
In traditional flexo printing, a 7mm thick printing plate is used. When the printing plate is pressed, the pressure of the raised graphic part is strong, and it is first compressed. The dot and text lines are easily deformed, the dot enlargement is intensified, and the plate making cost is also high. If the 3.94mm thin plate plus 3.05mm air cushion lining is used instead of the 7mm plate, the hardness of the air cushion lining is 20-25° Shore, which is lower than the plate hardness (the current commonly used plate hardness is 35° Shore). When the printing presses, the air cushion lining is compressed first, so that the plate is less deformed, as shown in FIG. 11 . The printing quality has been greatly improved and the cost of plate making can also be reduced.
2, the type of liner (1) rubber air cushion liner: is an ideal auxiliary material.
There are two types of air cushion liners:
Base film with PE base film: should be preferred, because it is easy to place on the plate roller, not easy to move, stick to the plate roller.
The PE-free base film was tested to have a rubber air cushion lining of the PE base film with a hardness between 20 and 25° Shore.
B, E-type good quality corrugated cardboard, printed cable, the choice of Shore 25 ° air cushion lining is better;
A, C-type flatness is poor, the general printing product selection of Xiao 20 ° air cushion lining is good. Air cushion lining can be used for a long time, available 1 to 2 years.
(2) Plastic foam cushions The plastic foam cushions are cheap, but the school version takes a long time and the pressure required is heavy. Because of the nature of plastic, it is easily deformed and has little resilience. It can also be used when it is used. If it is used for a long time, it will be biased, it will not recover its original shape, and it will not be able to fill the uneven thickness and thickness of corrugated paper. The effect is that the ink ribbon in the circumferential direction has a color difference and the print is not flat.
(3) R/bak air-cushioned cushion Recently, an American-made R/bak air-cushioned cushion has appeared on the market. R/bak is a polyurethane type material. Because its cushion material is 2 to 10 times more flexible than the resin plate or rubber plate, it has the advantages of high elasticity, no deformation, and rapid pressure recovery. Using R/bak air-cushioned pad technology to absorb the pressure generated between the printing substrate, printing plate and plate roller, can effectively prevent plate deformation and cardboard damage, make the ink transfer more uniform, and emboss dot surface printability Bigger, more clearly printed image levels. The main features of R/bak air cushion liner:
* Reduce the pressure of printing spots and effectively control the expansion of outlets;
* Avoid deformation of the printing plate and prolong the service life of the printing plate;
* It has a unique compensation effect for oversized plate rollers;
* Good printability for low quality corrugated paper and avoid damage to corrugated board;
* Improve the printing quality of traditional printing equipment.
The combination of a thin flexographic plate with R/bak pads is more suitable for printing fine images.
R/bak air cushion type lining plate technology is a mature technology widely used in corrugated carton printing. It is regarded as one of the most direct and most effective solutions to improve the quality of corrugated paper printing. The application of R/bak air-cushion lining technology has become an important way for domestic and foreign corrugated box printers and machine manufacturers to improve product quality. This combination of thin process and R/bak air-cushion lining technology is gradually replacing the traditional thick-type printing plate.
Third, the printing pressure adjustment and control Flexo printing is light pressure printing, so take pressure measures to improve the quality of printing, will only backfire, the limited amount of ink squeezed to the site does not require ink, so that the pressure is too flexographic The main cause of malfunctions such as hard ports (wild ink), burrs, and stencils. How to control the pressure, the key lies in the operation adjustment. Adjustment is actually to control the compression deformation of the printing plate. The smaller the deformation of the printing plate, the higher the printing quality. In the printing process, there are 3 pressure points (actually 3 embossing strips), namely the ink fountain roller and the metal anilox roller, the metal anilox roller and the plate cylinder, the plate cylinder and the impression cylinder. These three pressure points are all very important in terms of operation technology and should be printed under controlled conditions.
Correct control of the printing state should start from the following aspects.
1. The contact pressure between the ink fountain roller and the metal anilox roller can be slightly larger than the pressure of the metal anilox roller and the plate cylinder and the plate cylinder and the impression cylinder.
The role of the ink fountain roller is to squeeze out the ink on the surface of the metal anilox roller, so the pressure can be slightly larger. The control method is as follows: (to be continued)