1. Kraft paper that needs printing, when choosing paper, try to choose smooth surface and good flatness. Compared with other kraft papers, such as domestic natural kraft paper, refined kraft paper, Nine Dragons kraft paper, Lee & Man K series or above kraft paper, imported Russian Bratsk kraft paper has better surface smoothness and flatness than other kraft papers. In addition, the quality of kraft paper should be judged according to the customer's printing color requirements, what color to print, and how many colors to print.
2. Selection of models. Zhuhai kraft paper is generally available from 60/m2 to 500/m2, and paper above 80/m2 is not recommended to be printed with a small four-fold or eight-fold offset press. Because the kraft paper above 80/m2 is thicker, the suction nozzle often cannot absorb the paper during paper feeding. In addition, due to the small size of the paper, double or multiple sheets are prone to failure, or the paper is skewed on the feeding board. However, the effect will be better when printing thick kraft paper above 80g/m2 with a split offset press or a full-open offset press.
3. Adjustment of printing system. Adjust the suction volume of the suction nozzle before printing thick kraft paper in Zhuhai. At the same time, adjust the electrical devices such as double sheet control, skew control, and pre-punch control to prevent multiple sheets of kraft paper from damaging the machine. In addition, the paper separating nozzle and the paper feeding nozzle should use rubber rubber rings with larger diameter and thickness. When printing kraft paper, keep the center distance between the plate cylinder and the blanket cylinder unchanged, and only adjust the center distance between the impression cylinder and the blanket cylinder. When printing 250g/m2～450g/m2 kraft paper, the center distance can be extended by 0.2mm～0.4mm. The surface of kraft paper is rough and smooth, and the tightness of the paper is far less than that of coated paper and offset paper. Therefore, when printing kraft paper, the printing pressure must be increased accordingly.
4. Adjustment of printing color. The color of Zhuhai kraft paper is generally dark brown, and the printing color and bleached paper have a great printing effect. All the colors are bright and the effect is eye-catching. Now some kraft paper manufacturers also choose UV ink, refer to the ink color spectrum and the printing effect on different papers. Determine the printing color later.
5. Post-press processing. Due to the special structure of Zhuhai kraft paper, the fiber characteristics are good. It requires better processing equipment such as die cutters and punching. In this way, the high quality of the finished products can be guaranteed.