First, what is inverted wool
When printing a field, line, or text, there will be glitches on the edges of the graphic. This is what we often say. The burrs are said to fall in the direction of the bite, and the burrs are said to be smooth in the direction of the tip. It has a consistent direction in the printing plates, blankets and prints, otherwise it may be a phenomenon of extrusion, it may also be ghosting phenomenon.
Second, the influencing factors
When the following three factors exist at the same time will produce inverted hair: 1 plate cylinder and rubber roller lining is not correct, so that the radius of the plate cylinder and the radius of the rubber roller is not equal, but the difference is larger. 2 There are a lot of paper on the surface of paper, silty, sand, etc. off the blanket. 3 The printing plate metal matrix is ​​not rigid enough. The above three factors have nothing to do with the impression cylinder.
Third, failure analysis and solution
1, down hair: the emergence of inverted hair, in the case of the above three factors, when the R> R rubber, the linear velocity of the surface of the printing plate is greater than the linear velocity of the surface of the blanket, the two in the combined pressure to produce sliding friction The ink on the plate and the blanket is extruded in an opposite direction to each other. Due to the R > R rubber, the surface speed of the printing plate is fast, and the ink on the surface of the printing plate is elongated in the direction of the pulling. The line speed on the surface of the blanket is slow, and the ink on the surface of the printing plate stretches towards the mouth.
The ink stretched on the printing plate is removed due to the degreasing effect of the water roller and the water bucket syrup and the ink collection effect of the ink roller. Although elongated ink continues to be produced, it is continuously removed. Therefore, the ink stretch on the printing plate is instantaneous, so it does not become the root cause of bristling. The stretched ink on the blanket cannot be completely transferred to the paper. Due to the tackiness of the ink blot, more paper was deposited at the blot than elsewhere. These exfoliants become oily deposits when mixed with ink imprints. When sliding friction is generated by imprinting the printing plate and the blanket, it slides on the blanket in the direction in which the printing plate exerts force. As the oily deposits on the blanket are increasingly thickened in the direction of the imprint, the plate grains that come into contact with the place are worn out and damaged. It is also subject to oily erosion, gradually feeling fat and oleaginous, resulting in glitches and more and more glitches. This is the reason why the burr on the plate glows when a hair fall occurs.
Treatment method: Reduce the plate liner, increase the number of liners removed in the blanket, and appropriately increase the center distance between the blanket cylinder and the impression cylinder. If the blanket pad number meets the standard data, the center distance between the plate cylinder and the blanket cylinder should be reduced after the plate is removed.
2, Shun hair: When R India <R oak, under the three factors that produce inverted hair, it will produce hair. Its imprinting direction is opposite to that of inverted hair, and the genesis principle is the same as that of inverted hair.
Processing block: Reduces the liner in the blanket. If the plate liner is below standard data, the liner in the printing plate can be increased while the center-to-center distance between the impression cylinder and the blanket cylinder is reduced. If the plate liner thickness meets the standard data, it is necessary to reduce the center distance between the three rollers at the same time.
When printing a field, line, or text, there will be glitches on the edges of the graphic. This is what we often say. The burrs are said to fall in the direction of the bite, and the burrs are said to be smooth in the direction of the tip. It has a consistent direction in the printing plates, blankets and prints, otherwise it may be a phenomenon of extrusion, it may also be ghosting phenomenon.
Second, the influencing factors
When the following three factors exist at the same time will produce inverted hair: 1 plate cylinder and rubber roller lining is not correct, so that the radius of the plate cylinder and the radius of the rubber roller is not equal, but the difference is larger. 2 There are a lot of paper on the surface of paper, silty, sand, etc. off the blanket. 3 The printing plate metal matrix is ​​not rigid enough. The above three factors have nothing to do with the impression cylinder.
Third, failure analysis and solution
1, down hair: the emergence of inverted hair, in the case of the above three factors, when the R> R rubber, the linear velocity of the surface of the printing plate is greater than the linear velocity of the surface of the blanket, the two in the combined pressure to produce sliding friction The ink on the plate and the blanket is extruded in an opposite direction to each other. Due to the R > R rubber, the surface speed of the printing plate is fast, and the ink on the surface of the printing plate is elongated in the direction of the pulling. The line speed on the surface of the blanket is slow, and the ink on the surface of the printing plate stretches towards the mouth.
The ink stretched on the printing plate is removed due to the degreasing effect of the water roller and the water bucket syrup and the ink collection effect of the ink roller. Although elongated ink continues to be produced, it is continuously removed. Therefore, the ink stretch on the printing plate is instantaneous, so it does not become the root cause of bristling. The stretched ink on the blanket cannot be completely transferred to the paper. Due to the tackiness of the ink blot, more paper was deposited at the blot than elsewhere. These exfoliants become oily deposits when mixed with ink imprints. When sliding friction is generated by imprinting the printing plate and the blanket, it slides on the blanket in the direction in which the printing plate exerts force. As the oily deposits on the blanket are increasingly thickened in the direction of the imprint, the plate grains that come into contact with the place are worn out and damaged. It is also subject to oily erosion, gradually feeling fat and oleaginous, resulting in glitches and more and more glitches. This is the reason why the burr on the plate glows when a hair fall occurs.
Treatment method: Reduce the plate liner, increase the number of liners removed in the blanket, and appropriately increase the center distance between the blanket cylinder and the impression cylinder. If the blanket pad number meets the standard data, the center distance between the plate cylinder and the blanket cylinder should be reduced after the plate is removed.
2, Shun hair: When R India <R oak, under the three factors that produce inverted hair, it will produce hair. Its imprinting direction is opposite to that of inverted hair, and the genesis principle is the same as that of inverted hair.
Processing block: Reduces the liner in the blanket. If the plate liner is below standard data, the liner in the printing plate can be increased while the center-to-center distance between the impression cylinder and the blanket cylinder is reduced. If the plate liner thickness meets the standard data, it is necessary to reduce the center distance between the three rollers at the same time.
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