- Mar 14, 2018 -
1. Observe the sample sheet.
Sample inspection in printing. Soon after entering the official printing, the amount of ink to be determined at the beginning of the printing and the amount of water will be changed, and should be checked frequently and then adjusted. When the printing speed remains constant, the ink quantity and the amount of water are in a stable state, the sampling inspection shall be carried out according to the proportion of 500~1000 pieces per printing.
Put in a warning note. In the formal printing, for the place where the fault occurs, as a mark, it should be inserted into a long warning note, which is convenient for inspection in the latter process.
2. Pay attention to the change of water.
Note the change of water at the beginning of formal printing. Testing-run when the water and into formal on water after printing, how many will be some changes, you must pay attention to the sample for any side ghosting, carry water, one side note settlement plate yield.
Pay attention to the change of water during the official printing process. Please pay close attention to the machine body heat and ventilation to the effects of water within the workshop, alcohol education version should pay attention to wetting system cooling device, control the temperature of the good wetting liquid, too little water, can make the printing plate up dirty. Excessive water will cause the emulsification of ink, will bring a series of problems. For example, the printing is not glossy, the paper retractable and overprinter, slow ink drying, etc.
Pay attention to the change of ink.
Pay attention to ink of ink. Ink from the ink from the ink and ink from the gap between the blade, is from the ink of the self-weight and naturally squeezed out. Therefore, ink amount of ink in ink, directly affect the output of ink. So, be careful to keep a certain amount of ink in the ink. In addition, printing ink has a thixotropic property. When placed in ink for a long time, the liquidity will gradually deteriorate. Therefore, it is necessary to use the ink knife to stir in the ink, or to install the ink agitator.
Prevent ink from drying on the machine. Long downtime such as eating, resting, ink on the ink and ink on the ink surface will be dry. Can be sprayed with a dry inhibitor to prevent drying.
The density of the printed matter varies with the amount of water, room temperature and machine speed. Check with standard samples frequently. Notice to prevent inhomogeneity of ink color.
The pH value of wetting liquid is kept, and the pH value of wetting solution can be easily influenced by the addition of auxiliary agent in the ink. If the pH value increases, the printing plate will become dirty, so special attention should be paid to it.
Pay attention to the dirt on the back.
The back rub is due to the ink drying slowly, the ink layer is thick, the paper smoothness higher reason, the printing surface ink stick to the back of a printing plate.
5. Pay attention to double shadow failure.
The so-called "double shadow" is an image that is printed out with a plate, and can be seen double and triple in the print. There are many reasons for the double shadow, such as paper, teeth, roller, rubber cloth, printing speed, ink viscosity and other factors are very complicated. The following methods can be used to check the causes and to process them.
It is printed twice, observe the precision of the overprint, and check and adjust the side gauge drawing force, feed paper, press wheel and paper machine parts.
Check the tension of the blanket, the new blanket is easy to relax, and the attention should be tightened, but not too tight.
Check roller lining and printing pressure.
Look at the paper. Paper is poor, especially in the mouth of the paper, it is easy to have heavy shadow, so it should be checked.
Reduce the viscosity of the ink. The ink viscosity is high, paper can not smooth away the blanket, so that the tip of the paper is unstable, resulting in a heavy shadow. Can reduce the viscosity of ink properly.
The adjustment of the teeth. The poor adjustment and maintenance of the teeth is one of the causes of heavy shadow. Therefore, the adjustment and maintenance of the teeth should be carried out regularly to keep them in good working condition.
6. Pay attention to check the overprint.
Take out 20~30 prints continuously, then twist the edges of the paper and check the correct position of the front and the side gauge.
7. Pay attention to other work.
To supplement, stir and moisturize the ink.
Remove the dirty work. Because of ink residue, paper powder, paper wool adsorption on the plate or blanket, and reflected on the paper, it is necessary to remove dirt. In addition to the dirty work generally should be stopped. Unless there is a device that can remove dirt during operation. It is absolutely forbidden to remove the dirt directly when running.
To clean the rubber, plate and glue. When the blanket of ink, paper powder, powder powder and the transfer of ink, must stop cleaning the blanket, the operation should pay attention to safety. The cleaning and coating operations should also be considered safe.
Notice the abnormal phenomenon of the printing press. Pay attention to the sound, heat, vibration and smell of the machine. Check the current meter frequently, and pay attention to the abnormal condition of the printing machine.
8. Pay attention to the seal number.
At the end of the printing, it is necessary to confirm whether the printing number is consistent with the production construction sheet. If there is a missing number, the production manager shall be informed of the need for reprinting.