Label Printing Processing (1)

First, the appearance of adhesive material inspection In order to avoid the self-adhesive material itself as much as possible caused by the quality of the label printing failure, in the printing process, it is necessary to first look at the quality of the appearance of adhesive materials Inspections can be made in time to detect defects that may cause printing process quality problems before printing.
1. Check whether the adhesive material has burrs. The edge of the adhesive material is smooth and free of damage. It is the basis for ensuring the quality of the label printing. Therefore, the score of the adhesive material must be carefully checked before printing. Whether the cutting edges are burrs or not, whether they have been damaged due to improper storage and transportation, and roll 4-5 rolls of adhesive material, carefully check the cutting edge.
2. Check whether there are cracks in the adhesive material. When the material is cut, if the cutting tool is not adjusted properly or the cutting edge is not sharp enough, cracks or cracks will appear on the surface of the adhesive material or paper. The pulled fiber is again stuck by the adhesive. The occurrence of cracks may be continuous or random, and may occur on one side or the other side of the reel material. Therefore, before the adhesive material is printed on the machine, it is necessary to carefully inspect the bottom paper. If there is a small crack on the dough paper.
Then, take a piece of paper that has been inspected as described above, peel off the backing paper and check again whether there is a crack in the bottom paper and the bottom paper, because cracks are sometimes very small and can only be found after separating the backing paper and face paper. It is worth noting that since inks and adhesives gradually accumulate on the paper guide rollers of the printing machine during printing, cracks may also appear on the edge of the adhesive material. Therefore, even if printing has started, the above problems cannot be ignored.
3. Check whether the edge of the adhesive material is adhered or not, whether the bottom paper is coated with silicon, or the edge of the adhesive material is adhered or some areas of the bottom paper are coated with silicone oil. During the printing process, the paper will cause the paper to break when the waste material is discharged. normal production. Therefore, before printing, take a piece of adhesive material that is about 1 meter long, peel it off by hand, and see if there are parts on the edge or other parts that cannot be smoothly and uniformly peeled off. In general, the edge of the tissue paper and the edge of the backing paper occur on a slitting roll of the entire roll of coated adhesive material, and generally occurs only at the outer layer of 7 to 10 meters. Therefore, the roll that encounters slitting is not There is adhesion on the edge of the dry glue. Do not immediately say that the entire roll has this problem.
In addition, it should be noted that peeling off lightweight papers (such as 60 G/m2 and 80 G/m2 paper) uses more force than peeling, and the lighter the paper, the tighter the feel when peeled. Because of this, it is sometimes impossible to finish at the normal printing speed when the customer selects the self-adhesive material in the shape required by the customer.
4. Check whether the cutting end surface of the roll self-adhesive material is straight and whether the rewinder elasticity is consistent. If the slitting surface of the roll adhesive material is not uniform, it will not only affect the registration during printing, but also due to the position of die cutting. Difficulties in waste disposal occur due to changes; inconsistent elasticity during rewinding can cause changes in the paper strength during printing. Uneven tension can also cause print quality problems.
Second, printing failures and elimination Self-adhesive materials are usually printed and processed on the label linkage machine. The most common form of printing is embossing. Other printing methods are also used. Common faults in the printing stage are:
Fault 1 The ink on the label surface after printing is not dry, and drying is slow or the ink layer rubs off. Cause: The ink layer is too thick, the ink volume is too large, and the additives used in the ink are not suitable, the ink is denatured, or the type of ink used. Inappropriate, etc. will cause the label ink layer after printing to quit, dry slowly or the ink layer will wipe off; In addition, the machine runs too fast and dry......
The solution is:
1. Use a dark ink thin printing method to reduce the thickness of the ink layer;
2, the use of fast drying special ink;
3, the use of supporting the addition of Liu, plus the supporting desiccant;
4. Take measures to extend the drying or curing time of the printed matter;
5, increase the room temperature, the amount of exhaust, speed up the ink drying speed.
Failure 2 The ink on the surface of the film is poor in adhesion and easy to drop. If the surface of the film is not treated with corona, or the surface tension of the film is lower than the surface tension of the ink, the ink will not easily adhere; the characteristics of the unused ink and film materials are not This type of failure can also occur when matching or using non-special inks; failure to use such inks with expired or expired inks is inevitable. In addition, the drying device (UV or infrared hot air drying) has low power, so that the ink cannot be completely dried or the printing ink layer is too thick, the ink volume is too large, and the ink viscosity is too rough to embrittle the ink after drying for a long time, which will also result in thin films. The surface printing ink layer is poor in adhesion and easy to drop off.
The solution is:
1. Improve the surface tension of printing materials, and require the surface tension to reach 38 dyne/cm or more;
2. The corona device shall be installed on the rotary labeling machine, and the surface tension of the film shall be increased by random corona;
3, you can use transparent solvent-based ink to book bottoming to improve the surface tension of printing materials;
4. Select special inks and supporting additives matching with printing materials;
5, increase the drying or curing power, or reduce the speed of the machine, increase the drying time;
6, the printing ink layer should be as thin as possible, the amount of ink should be as small as possible, if necessary, multiple monochrome overprint;
7. It is recommended to perform UV glazing after printing to protect the printing ink layer and increase the adhesion of the ink layer.
FAULT 3 The poor adhesion of inks printed on FASCLEAR and PRIMAX Cause: Both FASCLEAR and PRIMAX materials are soft, matte surfaces with poor surface strength. Scratches may occur with a light fingernail stroke regardless of whether the surface tension is high or low. There will be problems with poor adhesion of ink, and inks that do not suffer from adhesion problems even on other substrates will have problems with poor ink adhesion on FASCLEAR and PRIMAX materials. The so-called ink drop here is actually the surface of the printing material is damaged, and the ink is not related at all.
The solution to the problem is:
Add hardeners to inks and varnishes, or purchase hardener inks, to improve the adhesion of inks to FASCLEAR and PRIMAX materials by increasing the frictional resistance and hardness of inks and varnishes. . (To be continued)