Partial troubleshooting of gravure printing press
There are many factors affecting the registration of color prints. The various steps involved in each printing process, such as paper, plate making, dampening solution, printing process, and equipment status, may affect the registration. Here we mainly analyze some common registration faults from a mechanical point of view.
(1) Factors affecting paper tension stability
The factors affecting the stability of paper tension are: paper frame, three-roll (infeed), variable speed roller (PIV) and other tension adjustment mechanisms and other paper guide rollers, paper feed roller working conditions. The tension adjustment mechanism of the tension adjustment mechanism is not suitable, or the parallelism and level deviation of various rollers are large, or the brake pads of the paper frame are worn, the wear of the roller bearings and the like may cause the tension to be unstable, thereby causing the gravure printing machine to be inaccurate.
(2) Factors affecting the transfer of graphics and texts
The printing unit acts as a direct printing part of the graphic transfer, and any mechanical deviation affects the registration of the printed product. The failure is mainly caused by the wear of the roller bearing, the severe wear of the copper sleeve or the bearing of the clutch pressure link mechanism, the looseness or improper installation of the plate pin, the wear of the register adjustment mechanism parts, the wear of the transmission parts, and the malfunction of the potentiometer. Although these faults are not common, the mechanical deviation of these parts should be carefully checked after the reasons for the tension factor are basically excluded.
4. Folding part failure analysis and elimination
The common faults displayed by the folding department are blocked, which causes many reasons. The main points are as follows:
(1) The rubber strip on the folding cylinder is used for a long time or aging, which causes the rubber strip to lose its elasticity or the slit is too wide and too deep, which causes the newspaper to be cut continuously. Several newspapers are easy to be blocked at the flower wheel. . The problem can be solved by replacing the new rubber strip.
(2) The cutter on the cutting drum is worn or the height of the cutter is not in place during installation, which causes the cutter to cut the newspaper and cause the newspaper to be blocked at high speed. The treatment method generally involves raising the knife holder, that is, adding a knife pad under the knife holder.
(3) The needle, the folding knife and the biting knife are seriously worn, or the corresponding cam roller bearing is stuck, or the corresponding torsion spring is broken, which will cause the folding to be in place and cause blockage. The fault can be resolved by carefully checking these parts and adjusting or replacing the corresponding parts as appropriate.
(4) The cutting knife just cuts the adhesive tape for automatic paper picking and fails to cut it to cause clogging. This phenomenon is generally rare and there is no suitable treatment.
(5) The paper itself is too wet or the water is too large, which makes it difficult to cut and cause the blockage when cutting. If the paper itself is too wet, replace the paper roll; if the water is too big, turn off the small amount of water in time.
(6) The adjustment of the diameter of the folding cylinder is not suitable or the tension adjustment before entering the folding portion is improper, which may cause blockage when the newspaper or the pinhole is pulled continuously. The treatment method is to check whether the folding roller diameter adjustment is appropriate and adjust as appropriate: check whether the shift roller tension adjustment is appropriate, and whether the platen roller on the shift roller is too tight or too loose is solved.