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Guide: Ink is an important material for printing.
It prints patterns and texts on paper through printing.
It is an indispensable material in the printing industry.
In the printing process, the ink is not scratched cleanly, which bothers many manufacturers.
Today, I will share with you 10 reasons why the ink is not cleaned during printing.
The content is for your friends' reference:
Ink
Ink is a homogeneous mixture composed of colored bodies (such as pigments, dyes, etc.
), binders, filling (filling) materials, additional materials, etc.
01Ink viscosity is too high
When the ink viscosity increases, its surface tension also increases, and the mutual force also increases, so that the impact force of the ink on the squeegee will be increased during the contact between the squeegee and the ink, and its equilibrium point will be destroyed.
The scraper cannot completely scrape the remaining ink on the plate roller, which directly affects the product quality.
02Scraper pressure is too small
Under normal circumstances, when the machine is just turned on, the squeegee pressure is often set very small.
As the machine speed increases, the impact force of the ink on the plate roller on the squeegee will increase with the increase of the machine speed, destroying the original balance point and directly The scratch is not clean.
03Ink enters moisture or has been used for too long
After the ink is used for a long time, on the one hand, the pigment in the ink will continue to precipitate during the long cycle process, which will change the composition of the ink.
On the other hand, the water vapor in the air will solidify due to the volatilization of the solvent and enter the ink.
04The solvent dries too quickly or slowly
The mixed solvent is too fast to dry, in addition to increasing the viscosity of the ink in a short time, it will also cause the ink to adhere to the vacant part of the plate roller.
Because the solvent evaporates too fast, the ink adhering to the plate roller will be gelatinous.
The solvent itself volatilizes very slowly, causing the free part of the ink on the plate roller to not be dried on the surface of the plate roller in time, and its state is similar to that of the ink with dots, so when the printing substrate passes the plate roller, the free part of the ink on the plate roller is easy The ground is transferred to the printing substrate, resulting in unclean scratches.
05 version roller use time is too long
Due to long-term use, the surface of the plate roller will be worn out due to the force of the scraper, and its surface will become smoother and smoother, resulting in an increasingly stronger affinity between the ink and the plate roller, which directly increases the difficulty of scraping by the scraper and causes failure to scrape.
Clean production.
06The scraper assembly is too soft and the angle is too flat
When the squeegee assembly is too soft and the angle is too flat, due to the effect of air pressure, the squeegee will bend on the surface of the plate roller, that is, the ink scraping point.
The method of scraping ink is not a "point" relationship but a "surface" relationship.
07 version roller assembly is not concentric
The phenomenon that the plate roller assembly is out of concentricity, under normal circumstances, the beating within 10 wires will not affect the color registration and product quality.
When the plate roller rotates from the side with the longer ellipse diameter to the side with the shorter ellipse diameter, the distance instantly becomes longer.
08 Solvent problem
A.
Since the solvent is added to the ink for use, the water in the solvent will directly damage the overall performance of the ink and cause unclean scratches.
B.
Improper solvent ratio will directly cause the ink to dry quickly or slowly, resulting in unclean scratches.
C.
The solvent itself has impurities, such as low purity and high water content.
09 Ink does not circulate
On the one hand, the non-circulating ink will make it difficult to control the viscosity.
On the other hand, due to the thixotropy of the ink, it will reduce the performance of the ink when it is not circulated.
In addition, it will cause the surface of the ink in the ink tank to crust due to the non-circulation.
, Directly increase the chance of the dry ink sticking to the plate roller, causing the phenomenon of unclean scraping.
10 Problems with Stirring Sticks
Since the protruding part of the ink stirring rod is more or less adhered to some ink after use, as the number of uses increases, the amount of ink also increases.
When the solvent is completely volatilized, the dry ink is left.
In the subsequent use process, because the ink in the ink tank cannot completely wet the dry ink on the convex part of the ink stirring rod surface, the gelled ink will be transferred to the surface of the plate roller during the operation of the ink stirring rod along with the plate roller.
Due to the strong adhesive force, the scraper cannot scrape it off when the plate roll runs for a week, and it is directly brought to the printing substrate, resulting in unclean scraping.
This phenomenon is especially obvious in the part without dots.
