Printing is a ubiquitous process in our life, with a very strict production process. Today, the editor will tell you something to pay attention to in printing.
1. Pay attention to the sample
① Sampling inspection during book printing.
Shortly after the official printing, the amount of ink supply and water consumption determined at the time of printing will change. So frequent sampling inspection and readjustment should be carried out. When the printing speed remains unchanged and the ink supply and water consumption are stable. The sampling inspection shall be carried out according to the proportion of 500~1000 pieces per printing.
② Clip in the warning note.
In the formal printing, as a mark, the place where the fault occurs should be sandwiched with a thin. And long warning strip to facilitate the inspection in the subsequent process.
2. Pay attention to the change of water supply
① Pay attention to the change of water at the beginning of formal printing.
The amount of water feeding during the trial printing and after entering the formal printing will vary somewhat. It is necessary to pay attention to the water feeding off the printing plate while observing. Whether the sample sheet has double images and water marks.
② Pay attention to the change of water during the formal printing process.
Pay close attention to the influence of the heating of the main body of the machine and the ventilation condition in the workshop on the water filling. And pay attention to the cooling device of the wetting system and control the temperature of the wetting solution for alcohol plate polishing. Too little water filling will make the printing plate dirty. Too much water will cause ink emulsification, which will cause a series of problems. For example, the printed matter is matt, the paper is stretched and overprinted incorrectly, and the drying of the ink is delayed.
3. Pay attention to the change of ink
① Pay attention to the ink in the ink bucket.
The ink from the ink bucket comes out from the gap between the ink bucket roller and the ink bucket scraper. And is naturally squeezed out by the weight of the ink. Thus, the amount of ink in the ink bucket directly affects the output of ink. Thus, pay attention to keep a certain amount of ink in the ink bucket. Also, printing ink has thixotropic property. If it is placed in the ink bucket for a long time, the fluidity will gradually deteriorate. So, it is necessary too often to use an ink knife to stir in the ink bucket or install an ink mixer.
② Prevent the ink from drying on the machine.
When the machine is stopped for a long time, such as eating and resting, the ink on the ink roller and the ink surface in the ink bucket will dry. The drying inhibitor can be sprayed at the place where it is necessary to prevent drying.
③ Pay attention to the uniformity of the ink.
The density of the printed matter varies with the water volume, room temperature, and machine speed. Compare and check with the standard sample frequently. Pay attention to prevent uneven ink color.
④ Maintain the pH value of the wetting solution.
After the auxiliary agent is added to the ink, it is easy to affect the pH value of the wetting solution. If the pH value increases, it is easy to cause the printing plate to be dirty, so special attention should be paid.
4. Pay attention to the dirt on the back
Scrubbing on the back is the phenomenon. That the ink on the surface of the printed sheet sticks to the back of the previous printed sheet. Due to the slow drying of the ink, the thick ink layer of the graphics and text, and the high smoothness of the paper.
5. Pay attention to ghost fault
The so-called double image is that the image printed by a printing plate is staggered. And the double and triple images can be seen on the printing plate. There are many reasons for ghosting, such as paper, teeth, drum, blanket, printing speed, ink viscosity and other factors are very complex. The following methods can be used to check the cause and deal with it.
① After printing twice, observe the overprinting accuracy, check and adjust the paper pulling force of the side gauge, the paper feeding wheel, the paper pressing machine.
② Check the tension of the rubber blanket. The new rubber blanket is easy to relax. Pay attention to tightening in several times, but do not be too tight.
③ Check the drum lining and printing pressure.
④ Check the paper suitability. The paper has poor adaptability, especially the paper with waves at its mouth, which is prone to double shadow, so it should be checked.
⑤ Reduce the viscosity of the ink. The ink viscosity is high, and the paper cannot peel off the blanket smoothly. Which makes the trailing part of the paper unstable, thus producing ghost. Can properly reduce the viscosity of the ink.
⑥ Adjustment of teeth in its mouth. Poor adjustment and improper maintenance of the teeth in its mouth are a major cause of the ghost. Therefore, the adjustment, maintenance and inspection of the teeth should be done regularly to keep them in good working condition.
6. Pay attention to check the overprint
Take out 20~30 prints in succession, twist the edges of the paper a little. And check whether the front gauge and side gauge are correctly positioned (two overprinting checks can be performed).
7. Pay attention to other work
① Ink supplement, mixing and wetting liquid supplement.
② Dirt removal. It is necessary to remove dirt due to the dirt of ink. Such as skin residue, paper powder, and paper wool adsorbed on the printing plate or blanket and reflected on the paper. Generally, the machine shall be shut down for dirt removal. Unless there is a device capable of removing dirt during operation. It is absolutely forbidden to remove dirt directly by hand during operation.
③ Cleaning rubber blanket, erasing and gluing. When the transfer of ink is affected by the accumulation of ink, paper powder and powder spraying on the blanket. The blanket must be shut down and cleaned. Pay attention to safety during operation. Attention should also be paid to safety during plate wiping and gluing.
④ Pay attention to the abnormal phenomenon of the printing machine. Pay attention to the sound, heat, vibration, smell, etc. When the machine is running, check the ammeter frequently. And pay attention to the abnormal conditions of the printing machine.
8. Pay attention to confirm the number of prints
At the end of printing, confirm whether the number of prints is consistent with the production order. If there is any shortage to be supplemented, the production management personnel shall be informed and the supplementary printing shall be arranged in time.
It is said that every penny is worth every penny. The editor suggested that you should choose a large and professional printing factory, so that the printed products will look good and keep for a long time.