An important reason for sticking blankets during offset printing
Published on Nov. 29, 2019
In the offset printing process, the paper sticky rubber means that the surface fibrous substances of the paper are adhered to the surface of the blanket by the ink during printing. Paper sticky rubber generally appears when printing on a solid plate with a large amount of ink. Especially when printing coated paper, when the printed ink layer is thick and the amount of ink is large, the phenomenon of paper sticky rubber is easy. occur.
Improper adjustment of the paper delivery mechanism of the offset printing machine is one of the causes of paper stickiness. Others have the following aspects. Today, offset printing ink supplier will learn the causes of paper stickiness with everyone.
1. The biting force of the impression roller biting the paper teeth is not enough
When offset printing is used, especially thick and high-grade coated paper, textured paper, offset paper, etc. are encountered. Large areas of the field, large ink consumption, thick and thick ink layers, and paper sticky rubber are easy to occur. The main reason is the bite of the impression cylinder. Caused by insufficient teeth bite.
Insufficient bite force of the bite teeth of the impression cylinder will cause inaccurate printing overprint. Increase the bite force of the bite teeth of the impression quick drying high gloss offset paper printing ink roller. The bite force of the bite teeth can be adjusted to make the bite force of the bite teeth uniform. If the overall teething force is still insufficient, you can increase the strength of the springs on both sides; if the teething pads or pressure pads are too smooth, the paper sticky rubber can be solved by sticking gauze on the teething pads to make the teething pads rougher. Can only bite the paper, to prevent the bite of the teeth is not enough, causing the paper sticky rubber failure.
2. The transfer time between the bite of the roller and the bite of the delivery is incorrect
In the offset printing process, the paper is swung from the swinging tooth to the paper, to the roller bite to complete the printing process, and then passed to the receiving bite. There must be a certain transfer time between them to ensure the accuracy of the overprint and the paper transfer process. Continuity. At this time, if the transfer time between the roller bite and the take-up bite is too short, the transfer time is too early, too late, or incorrect. It will instantly lose control of the paper and cause paper stickiness.
Adjust the position of the open plate at the joint between the paper-receiving bite and the roller bite, and control the transfer time of the two within the range of 3 to 6 mm.
3. Too little bite force when receiving paper
When the receiving paper bites the paper and bites the paper, the rear end of the paper is not detached from the offset printing ink roller. At this time, the paper will still be in a rolled state. The rear end of the paper is easily adhered to the surface of the blanket, which also causes the paper to stick to the blanket.
The biting force of the paper receiving teeth depends on the elasticity of the four supporting springs on the receiving paper biting shaft. If the overall biting force of the paper receiving teeth is too light, you can press the four supporting springs at the same time to increase the bite force, and then Adjust the biting force of each bite, use 60g / ㎡ kraft paper to reach into the bite, and pull the test to make the bite force on the middle and the ends of the teeth uniform.
If the bite teeth or pads are too smooth and cause paper stickiness, you can fix the gauze on the pads or stick the tape to the bite to troubleshoot the problem.