Tips of Kraft paper packaging and printing
Kraft paper is mainly used for printing of paper bags, envelopes, paper boxes, packaging of goods, handbags, information kits, Portfolio, the financial statements cover, etc., it has 60g / m2,70g / m2,80g / m2,100g / m2, 120g / m2,150g / m2 or 250g / m2 ~ 450g / m2 and other specifications. Kraft has a strong hard texture, good toughness, wear resistance, not easy to tear fracture and other advantages. But Kraft whiteness, smoothness and flatness is poor, rough paper surface, prone to under upturned Grilled, hair loss, powder from the phenomenon. Therefore, to use offset-printed kraft paper, should have the following points.
1. Before printing will be hanging to dry the humidity kraft process. First, the uneven surface tattered paper and paper removed, and then the ashes paper surfaces clean of impurities, and then hang to dry processing, the Kraft temperature, humidity, and offset printing workshop temperature and humidity consistent. This prevents uneven moisture content of the paper because of the emergence of the phenomenon of upturned bottom band. Paper by hanging to dry the humidity treatment, and then the paper stack above the pressure on the paper, plywood, iron plates, large stones compacted to avoid paper fluffy untrue.
2. selected models. For 80g / m2 or more thick brown paper, best not to use a small quarto or octavo offset printing. Because 80g / m2 or more thick brown paper, when the paper feeding nozzle often can not afford to suck. Further, since the paper format is small, prone to double or more sheets fault, or paper feeding board skew. But with full Offset printing offset press or 80g / m2 or more thick brown paper, the effect will be better.
3. Adjust offset feeding system. Because of the thick brown paper, it should regulate the amount of intake air nozzle size. Meanwhile, the paper thickness are likely to cause an accident to stop rolling, so be sure to double before starting the printing sheet control, skew control, impulse control and other electrical devices before adjustment appropriate to prevent multiple sheets of kraft paper machine roll bad. In addition, the paper feed nozzle and nozzle diameter and thickness to be used are larger rubber apron.
4. When printing kraft paper holding plate cylinder and the blanket cylinder of the same center distance, only adjust the blanket cylinder and the impression cylinder center distance. When printing 250g / Kraft m2 ~ 450g / m2 may widen this center distance 0.2mm ~ 0.4mm. Kraft paper rough surface smoothness is poor, the tightness of the paper is far better than coated paper, offset paper, therefore, when printing kraft paper printing pressure also increased accordingly.
Gap kraft paper such as printing, plate cylinder and the blanket cylinder of 400g / m2 is 3.95mm, the blanket cylinder and the impression cylinder gap adjustment of 3.40mm, a total plate cylinder liner of 0.65mm ~ 0.75mm, the blanket cylinder The total package lining