Talking about the Preprinting Technology of Corrugated Box Gravure (2)

Corrugated box gravure production equipment and process

1. Major equipment

The main equipment used for corrugated box gravure preprinting is a large-sized group gravure printing machine. The pre-printed noodle paper is placed on the noodle station of the corrugated board production line, and after the processes of sizing, veneering, flattening, drying, cutting, etc., the colored cardboard is made, and then the die-cutting, sticking box, etc. Add TZ order to complete corrugated box production.

2. Requirements for corrugated board production line

The important configuration of the corrugated carton gravure preprinting line is the computerized crosscutting control device of the corrugated cardboard production line. The main control principle is that the photoelectric eye recognizes the crosscut mark on the corrugated cardboard printing pattern, and gives control when the crosscut mark reaches the photoelectric eye. The computer sends an instruction, and the control computer controls the cross-cutting time so as to accurately cut the corrugated cardboard at the boundary of the pattern. At present, China's production of corrugated board production lines can be installed according to customer requirements computer cross-cutting device, cross-cutting accuracy can be controlled within ± 0 5mm.

3. Choice of ink

The ink used in the prepress gravure printing machine is mainly based on alcohol-soluble inks or gravure inks for aqueous paper.

When the preprinted paper is flattened and dried on a corrugated board production line, the ink used requires high temperature resistance and good abrasion resistance, otherwise, the preprinted color surface will be pulled or the dragging phenomenon will occur. At present, the "Tianshi" brand water-based ink produced by the Tianjin Toyo Ink Factory can meet the demand for waterborne paper gravure printing, with low cost, no pollution, and meets the national environmental protection requirements. The gravure carton preprinting ink produced by Shanxi Essence Industry & Trade Co., Ltd. is based on cellulose. The main solvents are alcohols and esters. Compared with aqueous inks and offset inks, the inks have bright color, high gloss, and can withstand friction and It is resistant to high temperature of 180--250~C, good printability, clear printing patterns, delicate layers, etc. At the same time it has excellent adhesion to most substrates.

4. Plate Selection

The gravure pre-print is made of steel chrome-plated electric gravure, which is completely suitable for field printing and layered printing. The gravure used for paper printing is deeper than the gravure cell used for plastic printing. The price of gravure plates has now dropped from 0.7 yuan/orQ' to about 0.3 yuan/em', or even lower, and the gravure printing capacity can reach 3 to 14 million in India. At present, there are a large number of domestic manufacturers of rotogravure plates, and electric carvings and gravure plates manufactured by Shanghai Shipping City, South Plate Making, and Sanmenxia Blue Snow have all reached the international advanced level.

5. Paper selection

The substrate used for gravure preprinting must be coated whiteboard with good surface smoothness, strong printability, and stable water content (6% to 7:6). Imported coated kraft paperboard and homemade grey board can meet the paper requirements of high-grade colored corrugated box paper. At present, the quantitative range of paper is 150-350g/m2, and 1 85g/m'2 coated paper has been widely used in China. U.S. Mead Paper has been using 500g/m2 virgin wood pulp to coat kraft paper gravure printing cartons and canned beer cartons, and its strength is better.

Corrugated carton preprinted common problems and solutions

Corrugated carton preprinted common problems and solutions are roughly as follows.

1. Wrinkling

High-quantity preprinted paper rolls have large tension and are more difficult to control than films and tissues. When the moisture and thickness are not uniform, it will cause the paper to swing laterally and form folds on the printed surface. The addition of a preheating device helps to reduce the paper tension change caused by moisture loss (when the moisture content is too low, install the humidifier); if you add a misalignment flattening roller, it will help the paper roll to flatten as much as possible while reducing the swing. .

2. Ink pull flower

Solve the problem of ink pull flowers, in addition to the use of temperature-resistant ink and Varnish, the use of the latest air-cushion heating plate heat transfer control system can reduce the heating temperature and strength of the paper board through the heated end, so as to avoid the cardboard caused by excessive pressure Traces, ink and other phenomena.

3. Lubai

It is mainly caused by dust and ink blocking on the surface of the paper roll. The installation of dust-removing and explosion-proof electrostatic ink-absorbing devices in the field printing color group can effectively remove dust, improve the ink repellent effect, and reduce the loss of network points.

4. Spiral winding

To solve this problem, a closed-loop control system should be used to ensure the tension taper control.

5. Uneven rolling

To solve the problem of uneven winding ends, the backup roller (receiving rubber roller) can be added to remove the air in the paper roll and eliminate static electricity on the surface. When the paper roll receives the material, the roller device is attached to reduce the edge swing. The installation of a PLC correction device or the use of an off-line rewind method also helps to alleviate the problem of uneven winding.

6. Paper lap

Improper overlap of the paper roll during the printing process will cause downtime and affect the consistency of the printed product. This phenomenon can be avoided by zero number butt-joint method, without interrupting the printing process.

Jiangxi Press and Publication School Nan Jingsheng

Source: Printed packaging. Decoration Technology