Causes and elimination of ink stick during CD printing
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The ink color of the horizontal strip bar portion appearing on the printed matter surface is obviously deeper than the ink color of other parts belongs to the ink bar, and the reason and elimination method for generating the ink stick are as follows:
1. The ink bar caused by the brake bar
When the contact pressure between the rubber roller and the brake bar is too large, then when the ink roller and the brake bar contact and roll during the operation of the machine, impact wear occurs. For this, the contact pressure between the rubber roller and the printing plate should be adjusted to maintain uniformity. Moderate contact conditions, after eliminating excessive resistance, the ink bar can be better eliminated. Replace the front end with a section of approximately 40 mm when the brake bar is severely worn.
2, the rubber roller caused by the rubber roller
When the contact pressure between the rubber roller and the printing plate is too large, when the ink roller and the printing plate are in contact with the roller brush during the operation of the machine, the impact is easily generated and the tremor is caused, so that the frictional force is increased to cause streaks. If the pressure of several inking rollers is too large, the density of the bar marks will be greater. In this regard, the contact pressure between the rubber roller and the printing plate should be adjusted to maintain uniform and moderate contact conditions, and the ink bar can be better eliminated after eliminating excessive resistance.
3. Roller gear wear, excessive gear clearance or foreign matter accumulation between gears
When the roller gear wears, the gap or the foreign matter adheres between the teeth, during the operation of the machine, the drum gears cannot be precisely meshed, so that the linear speed between the rollers is not consistent. In addition, the backlash is too large, and the drum is also prone to chattering and shaking, forming a printed bar mark, causing a trace of the ink stick that is similar to the gear pitch. There is a foreign body obstacle in the backlash, and it is easy to cause the drum to tremble due to the phenomenon of "top teeth", so that the lateral layout of the printed product forms a strip of ink stick. In this regard, the center distance between the rollers should be re-adjusted to reduce the gap between the teeth; for the gears with strong wear, the new gear should be replaced; the foreign matter adhered between the teeth should be cleaned to achieve the effect of eliminating the ink stick.
4, the roller bearing appears large wear
When the roller shaft head is running out of oil or the machine wears natural wear for a long period of time, the gap between the roller shaft head and the bearing is increased, and the mismatching is caused, and the ink stick trace is caused by the chattering when the pressure is combined. In this regard, it is advisable to make the rubber inner liner into a trapezoidal shape to reduce the impact during the imprinting state and to reduce the degree of the ink stick. In addition, if the roller bearing is seriously worn, it should be considered to adopt plating repair or replace the new bearing to eliminate the ink trace.
5, the plate cylinder or blanket cylinder liner is too large
If these two conditions exist, the strip-shaped ink stick marks will be caused by the inconsistent surface linear velocity, and at the same time, the impact of the drum will be caused by the impact of the drum during the imprinting, and the contact between the two rollers will easily cause friction and cause the ink stick trace. In addition, sometimes the ink stick is easily caused by the fact that the imprint of the bite portion is not conspicuous (the pressure is light) and the pad of the pad is excessive. In this regard, the thickness of the lining should be accurately adjusted, and the minimum printing pressure should be used to make the ink layer uniformly transfer, so as to maintain the uniform line speed between the rollers as a prerequisite. When adding a paper strip to the bite part, it should be carried out by gradually heating the pad. Do not pad at once, so as to avoid the appearance of the ink stick trace.
6, Blanket (blanket) loose
Sliding friction is likely to occur during rolling, and a strip of ink stick marks appears. Therefore, measures should be taken in time to tighten to prevent the printing of ink sticks.
7. When the self-adhesive Blanket is replaced, the old primer is not cleaned, and the partial pressure is inconsistent, causing the ink stick trace.