Offset Common Frequently Asked Questions for Computer Bills Offset 2

Fifth, blanket roller lining problem

The blanket of computerized offset printing press has high elasticity, good degree of vulcanization, less plastic deformation after multiple imprints, strong lipophilicity, solvent resistance, oil resistance, heat resistance, corrosion resistance, abrasion resistance, aging resistance, and smooth surface. Smooth blanket. When choosing a lining for the blanket cylinder, use a neutral lining. In this way, on the one hand, it is conducive to clear lines, text, and plain clothes; on the other hand, it can also reduce the impact of residual paper powder and paper hair on the blanket during the computer paper production process, extend the service life of the blanket, and improve the printing quality of the ticket. .

Sixth, solve the problem of broken paper

In the process of computer ticket paper printing, it is affected by various factors, leading to paper breakage, interruption of printing, and waste of paper. This is a common problem in the printing of computer tickets. The main causes are the following aspects.

1. Paper suitability and the quality of computer paper production

The change of the moisture content of the computer paper easily causes the paper to shrink and pressurize and cause the paper to break.

If the quality of computer paper in the production process, such as the two sides of the hole is not symmetrical, paper cutter knife marks are too deep, paper creases, etc., can cause computer paper in the printing due to unbalanced paper feeding, paper pressure inconsistent, easy Affected by roller pressure, peel tension, etc.

2. Peel tension of paper

When the paper is peeled from the blanket by embossing, it is subjected to the peeling deformation due to the adhesion force and the peeling force. This force to overcome the mutual adhesion of the paper and the blanket and to peel the paper is called peel tension.

Paper under the role of stripping tension will produce plastic stripping deformation deformation, easy to make the paper size changes caused by overprint graphics are not allowed. In the computer ticket printing process, the computer paper passes through the tangent and the needle edge, so that the peeling tension is too large, which is the main cause of paper breakage. The main factors that determine the peeling tension and the paper stripe deformation and cause the paper to break include the following aspects.

(1) Roller pressure and relative stamping time. The larger the roller pressure, the longer the stamping time, the more complete the contact between the paper and the blanket, the greater the mutual adhesion between the paper and the blanket, the greater the peeling force required to peel the paper, and the more the computer paper. Easy to break. When the drum pressure is large, the drum pressure may be appropriately reduced by changing the thickness of the drum liner or adjusting the center distance of the drum.

When the back side of the printed document is printed, if the front surface ink is not completely dried, the front surface of the ink is likely to adhere to the surface of the impression cylinder when the back surface is printed. With the thickening of the adherent ink layer, the printing pressure is also gradually increased, and when the pressure is too high, the web breaks. Therefore, care should be taken to clean the surface of the impression cylinder when printing on the back side. In addition, adding appropriate amount of drying oil to the ink on the first side of the printing, appropriately thinning the ink layer, stacking the semi-finished products reasonably, and accelerating the drying of the ink.

(2) The adhesiveness of the blanket. When the surface of the blanket is swollen and sticky due to the action of the organic solvent, its surface adhesion is enhanced and the peeling tension is increased. After cleaning the blanket, apply a layer of talc to the surface.

(3) ink viscosity and layout moisture. The greater the viscosity of the ink, the greater the moisture content of the plate, and the increased adhesion of the paper to the blanket increases the peel tension.

(4) Stripping speed. The peeling speed mainly depends on the machine speed. The faster the machine speed, the greater the peeling tension, and vice versa.

(5) The size of the peeling angle. The peel angle is the angle at which the paper is peeled from the blanket. The larger the peel angle, the greater the peel tension. The size of the peeling angle can be changed by mechanical adjustment.

3. Paper failure

When the paper feeding chain picks up the paper, too much force can cause the paper to be stretched too tightly, resulting in too much force and breakage of the paper. The uneven pressure or improper pressure on the top of the paper feeding cover can also cause the paper to break. For example, the pressure of the paper is not uniform due to the wear of the paper on the paper cover. This causes the paper to be affected by the axial force in the conveying process. The middle bulges, causing the paper to detach or break on one side. In addition, if the paper-pressing cover presses plastic to accumulate too much dry ink or paper, it will cause poor paper feeding and paper jams, which will cause the paper to break. At this point just wipe the paper and press plastic to solve the problem.

(Guangdong Jieyang City Pentium Paper Co., Ltd. Jiang Chuangpeng)