1. Ink factor
1. The effect of ink viscosity
The viscosity of the ink should match the printing speed, the viscosity of the ink is too high, and the adhesion to the plate cylinder is too strong, which is not conducive to the scraping knife to scrape off the excess ink on the plate surface, and the probability of cutting lines is high during printing. During the printing process, the ink viscosity should be measured and controlled at regular intervals, generally every 20 to 30 minutes.
2. The effect of ink drying
If the ink dries too fast, it is prone to skinning. If the skinning is not dissolved during the ink circulation process, it will stick to the blade or the bottom of the blade once it comes into contact with the doctor blade, resulting in a printing line. If the ink circulation system uses an open ink tank, ink caking and caking are more likely to occur. In order to reduce the occurrence of such knife line faults, the ink in the ink tank should be stirred frequently; an appropriate amount of slow drying agent should be added as needed; if necessary, a sealing cover can be added to effectively control and reduce printing knife line faults.
3. The influence of ink fineness
The fineness of the pigment particles has a direct impact on the appearance of the knife line. For example, the pigment particles used in blue ink have high hardness, and even after sufficient grinding, it is difficult to achieve a very fine particle size, and it is easy to damage the ink during the printing process. The knife may affect the effect of scraping ink, and the knife line often fails when printing blue ink.
4. The influence of ink activity
In the production process of ink, a certain amount of active agent is generally added. The plate cylinder also has a certain activity after chrome plating. If the activity of the ink and the plate cylinder is too high, the active substance will firmly adhere to the cylinder during printing, and it is difficult for the doctor blade to scrape it off, thus forming a knife line. At this time, first clean the plate cylinder to remove the active substances on the surface, and add an active retarder to the ink to eliminate the knife line.
5. Influence of ink quality
If the ink is stored for too long, the solvent balance will change, causing the solubility of the ink to decrease; or if the ink is improperly formulated or used, causing a chemical reaction, the ink will precipitate. In the printing process, the deposits in the ink are easy to accumulate in the blade of the doctor blade and cause the knife line, so the ink needs to be replaced.
Second, the printing plate factor
1. The effect of surface finish
If the gravure printing plate fails to polish the burr during polishing, the ink with burrs on the plate surface is not easy to be cleaned during the printing process. In serious cases, the squeegee will be damaged, thereby forming a knife line. For the printing line caused by the rough surface of the printing plate, 1200 mesh fine sandpaper can be used to lightly polish the printing plate, but in general, it is best not to polish the printing plate, so as not to damage the printing plate.
2. The influence of chromium layer hardness
When making a plate, if the chrome plating is too long, the hardness of the chromium layer on the surface of the printing plate is too high, and it is easy to damage the doctor blade, and the indefinite cutting line will appear on the printing. On the contrary, if the chromium plating is too short, the chromium layer on the surface of the printing plate is too soft, the squeegee is easy to damage the printing plate, and a fixed knife line will appear on the printing.
3. The influence of the cleanliness of the layout
The debris generated by the grinding process of the plate-making process is not completely removed and adheres to the printing plate. During the printing process, the printing plate and the squeegee will be damaged, resulting in a knife line. Before printing on the machine, it is best to clean it thoroughly with solvent to remove oil and impurities to reduce the occurrence of printing knife line faults.
4. Influence of machining precision
The poor machining accuracy of the printing plate cylinder will also lead to printing knife line failure, and it is difficult to detect or difficult to detect, so it is easy to be ignored. In actual operation, it can be checked on the machine. In addition, the installation accuracy of the printing plate should also be strictly controlled to avoid excessive impact on the squeegee due to excessive concentricity errors and high-speed printing, which can cause printing line faults.
Third, the impact of the doctor blade
1. The hardness of the doctor blade
The hardness of the doctor blade is lower than the hardness of the chrome layer on the surface of the printing plate. If the hardness of the squeegee is too high, it will accelerate the wear of the printing plate and produce scratches: if the squeegee is of poor quality, it will wear out in a short period of time, resulting in the ink of the plate surface not being cleaned, and the appearance of the knife line At this time, frequent tool adjustments and tool changes are required.
2. There is a gap in the squeegee blade
When the squeegee blade is damaged and there is a gap, there will be a regular line of left and right movement on the printing, which is easier to identify. If the gap on the doctor blade is relatively fine, it can be polished with oilstone or fine sandpaper until smooth and smooth. If the gap is large, the doctor blade needs to be replaced. When replacing the knife, the accumulated ink on the pressure blade and the knife groove must be thoroughly cleaned to avoid affecting the flatness of the installation of the doctor blade, and the length of the blade exposed to the pressure blade should be the same, about 5mm. In the printing process, some squeegee blades need to run in with the printing plate for a long time to achieve a good squeegee effect. At this time, metallographic sandpaper can be used to smooth the blade edge of the squeegee blade, so that the squeegee blade can reach Better scraping effect, and is conducive to the improvement of productivity.
3. The flatness of the installation of the doctor blade
The poor flatness of the squeegee installation can also cause printing lines. Therefore, when installing the doctor blade, make sure that the flatness is good, so that the doctor blade is evenly stressed.
4. The pressure and angle of the scraper
The pressure and angle of the doctor blade also have a great influence on the printing blade line. During printing, the angle and pressure of the squeegee blade should be adjusted according to the degree of squeegee and the inking condition of the printing, so as to achieve a good squeegee effect, thereby reducing the occurrence of printing knife line faults.
Fourth, the effect of solvents
In the printing process, if the solvent is used improperly, the ink is not fully dissolved and sticks together. Once it sticks to the doctor blade, a knife line will be formed. This kind of knife line is usually a dark line, sometimes there is no. It is more common to print solid color blocks with gold ink. Since gold ink is formulated with gold powder, gold oil and solvent, the metal particles are relatively heavy and easy to precipitate. If the solvent used has poor solubility, and the stirring is not Fully, metal particles will accumulate due to uneven distribution. If it stays at the blade of the squeegee, a thick dark line will form. The characteristic of this dark line is that it disappears automatically after a period of time, and then forms again, which seriously affects the printing quality. This type of knife line is difficult to eliminate in printing. It is necessary to start from the roots and work from the pre-printing preparation work. Use appropriate solvents when mixing the ink, stir it to fully dissolve, and maintain a good ink circulation during printing.
The canvas wig head is made of 100% cork. compared with poly filled canvas head, cork canvas head is more sturdy and durable.
Professional canvas block head professionally designed according to human's head shape, have more refined appearance. You could put pins and hold wigs easily. Very easy and convenient to use, great for wig making, fixing wig making, styling and display.
The wig head base has mounting holes (about 1 inch in diameter) that match most Wig Stands or tripods on the market. The clamp stand is included in the package, please refer to the steps shown in the picture to install the clamp stand.
You can measure your head circumference by going around the head behind the ears from the nape of the neck round to the front hairline.
Cover the head with some plastic wrap before making wigs. Please put it in a dry and ventilated place. Please put it under sun once a month.
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Xuchang Le Yi De Import And Export Trade Co., Ltd. , https://www.lileaderbeauty.com