Eight precautions during the printing process

Eight precautions during the printing process
Specializing in the production of a variety of automatic and semi-automatic box making machines, including pasting machines, corner stickers, forming machines, grooving machines and accessories!
1. Pay attention to the samples
(1) Sampling inspection during printing.
Soon after entering the official printing, the amount of ink supply and water supply determined at the time of printing will change somewhat, and it should be frequently sampled and checked and readjusted. When the printing speed remains the same, and the ink supply and water supply are stable, sampling inspection is carried out according to the ratio of 500~1000 sheets/time per printing.
(2) Clip in the warning note.
In formal printing, a slender warning slip should be inserted as a mark for the place where the fault occurs, so that it can be easily checked in the post-process.
2. Pay attention to the changes in Sheung Shui
(1) Pay attention to the changes in the water supply at the beginning of formal printing.
The amount of water during trial printing and the amount of water after entering the official printing will change somewhat, so be sure to pay attention to whether there is a double image and water carrier in the sample sheet, and pay attention to the water supply of the adjustment plate.
(2) Pay attention to the changes in the water supply during the formal printing process.
It is necessary to pay close attention to the influence of the heating of the main body of the machine and the ventilation in the workshop on the water, and pay attention to the cooling device of the wetting system to control the temperature of the wetting liquid. Too much water will cause the ink to emulsify, which can lead to a series of problems.
For example, the print is dull, the paper is stretchable and the overprint is not accurate, and the drying of the ink is delayed.
3. Pay attention to the change of ink
(1) Pay attention to the ink of the ink fountain.
The ink of the ink fountain comes out of the gap between the ink fountain roller and the ink fountain scraper, and is naturally squeezed out by the ink due to its own weight.
Therefore, the amount of ink in the ink fountain directly affects the output of the ink.
So, take care to keep a certain amount of ink in the fountain.
In addition, printing inks have thixotropic properties.
If you leave it in the fountain for a long time, the fluidity will gradually deteriorate, so it is necessary to stir in the fountain frequently with an ink knife or install an ink stirrer.
(2) Prevent the ink from drying on the machine.
When there is a long downtime such as eating or resting, the ink on the ink roller and the ink surface in the ink fountain will dry.
A desiccancy inhibitor can be used to spray on the area where dryness needs to be prevented.
(3) Pay attention to the uniformity of the ink, and the density of the printed matter varies depending on the amount of water, room temperature, and machine speed.
Comparison with standard samples should be performed frequently.
Take care to prevent uneven ink color.
(4) Maintain the pH value of the wetting solution.
After adding additives to the ink, it is easy to affect the pH value of the wetting solution, and if the pH value increases, it is easy to cause the printing plate to be dirty, so special attention should be paid.
Fourth, pay attention to the back of the dirty
The dirty back side is due to the slow drying of the ink, the thick layer of graphic ink, and the high smoothness of the paper, so that the ink on the surface of the printing sheet sticks to the back of the previous sheet.
5. Pay attention to ghosting failures
The so-called ghosting is the misshift of the image printed on a single printing plate, and the double and triple images can be seen on the printing sheet.
There are many causes of ghosting, such as paper, teeth, rollers, blankets, print speed, ink viscosity and other factors are very complex.
The following methods can be used to check the cause and deal with it.
(1) Print twice, observe the overprint accuracy, check and adjust the side gauge paper pulling force, paper feeding, paper pressing wheel, and paper pressing machine parts.
(2) Check the tension of the blanket.
The new blanket is easy to loosen, so be careful to tighten it in stages, but not too tight.
(3) Check the cylinder lining and printing pressure.
(4) Check the suitability of the paper.
Poor paper adaptability, especially paper with waves at the mouth of the mouth, is prone to ghosting, so it is necessary to check.
(5) Reduce the viscosity of the ink.
The ink has a high viscosity, and the paper cannot be peeled off the blanket smoothly, which makes the trailing part of the paper unstable, resulting in ghosting.
The viscosity of the ink can be appropriately reduced.
(6) Adjustment of the teeth.
Poor adjustment and improper maintenance of the teeth are a major cause of ghosting.
Therefore, it is necessary to do a good job of adjusting and maintaining the teeth regularly to keep them in good working condition.
6. Pay attention to check the overprint
Take out 20~30 prints in a row, twist the edge of the paper a little after breaking through, and check whether the front gauge and side gauge are positioned accurately (two overprint checks can be carried out).
7. Pay attention to other work
(1) Replenishment of ink, stirring and wetting solution.
(2) Dirty removal operation.
It is necessary to remove dirt because the slag of ink, paper powder, paper wool and other stolen goods are adsorbed on the printing plate or blanket and reflected on the paper.
Dirt removal operations should generally be stopped.
Unless there is a device that can remove dirt during operation.
It is absolutely forbidden to remove dirt directly by hand while running.
(3) Cleaning eraser sheets, plate wiping and gluing operations.
When ink, paper powder, and powder powder accumulate on the blanket and affect the transfer of ink, the blanket must be stopped for cleaning, and safety should be paid attention to during operation.
Plate wiping and gluing operations should also be done with safety.
(4) Pay attention to the abnormal phenomenon of the printing press.
Pay attention to the sound, heat, vibration, smell, etc. when the machine is running, check the ammeter frequently, and pay attention to the abnormal situation of the printing press.
8. Pay attention to confirm the number of prints
At the end of printing, it should be confirmed whether the print quantity is consistent with the production construction order.