Installation notes
(1) First replace the liner paper before installing the blanket, and accurately measure the total thickness of the liner paper. The measurement method is: first measure the thickness of a piece of liner paper, then calculate the amount of liner paper required, and finally measure the total thickness of the liner paper. If the total thickness error is greater than 0.02 mm, the liner paper should be appropriately increased or decreased to make the total thickness more precise. If the total thickness of the liner paper is large, the following undesirable phenomena are likely to occur: the printing pressure is too large, and the printing is too large.
The wear of the plate is intensified; the graphic mesh is subject to extrusion deformation; the printing work of turning over is easy to produce a pile imprinting phenomenon, resulting in waste; the printing work in the field is prone to paper peeling. If the total thickness of the liner paper is small, the printing pressure will be too small, resulting in improper printing of the graphic, the dot is faint, and even the ink is not printed. Therefore, be careful and accurate when measuring the total thickness of the liner paper.
(2) When fixing the blanket, first place the blanket in a suitable installation position, and then tighten the clamping screw of the blanket. The force should be moderate and uniform. After tightening all the clamping screws, it is necessary to perform another time. Check them one by one to avoid missing situations. It should be noted that before tightening the clamping screw, it must be ensured that both ends of the blanket are in the installed position, so that one end of the blanket is fixed by the clamping screw, and the other end is away from the installation position.
(3) During the process of tightening the blanket, be sure to clamp the clip of the blanket into the butterfly clip of the blanket cylinder to ensure that the blanket is fully clamped.
In addition, the strength of the blanket should be appropriate. If the force is too large, the problem that the blanket is detached or the elasticity is reduced is likely to occur, which affects normal printing; if the force is too small, it may easily cause vertical ghosting and the like of the printed product.
Scrubbing notes
(1) The amount of cleaning agent on the cotton cloth should not be too large, and it is not difficult to scrub the blanket with cotton cloth. In order to avoid using too much physical force in the process of scrubbing the blanket, the operator usually likes to pour more cleaning agent on the cotton cloth, which will bring some adverse consequences, such as excessive printing on the blanket after printing. The cleaning agent will be embossed onto the plate and will be smashed onto other parts during operation, which will result in more printed waste. In addition, most cleaning agents are less volatile, so more attention should be paid to controlling the amount of cleaning agent.
(2) Pay attention to the presence or absence of indentation on the surface of the blanket (especially when the shifting and paper feeding are not smooth). Once it is found that there is an indentation, on the one hand, it is necessary to check the image area on the corresponding position of the printed product in time to see if there is a lack of net phenomenon. On the other hand, use a blanket repairing agent (a special plaster capable of reducing the elasticity of the blanket) to indentation. Restore at the place. If the indentation is deep, you need to lay a thin layer of paper or tape on the back of the blanket to ensure that the surface of the blanket is basically flat to avoid the phenomenon of missing mesh in subsequent printed jobs.
(3) Pay attention to the presence or absence of water droplets in the back of the blanket or printing plate. If there is water droplets, the water supply may be too large. The water supply should be reduced or the pressure of the water roller should be adjusted to avoid the phenomenon of large ink washing. .
(4) Observe whether there is any ink accumulation on the surface of the blanket. In the cold winter, the phenomenon of ink accumulation is most likely to occur. This is because when the temperature is low, the viscosity of the ink is large and cannot be fully transferred to the paper, which tends to cause the paper to stick to the blanket and damage the blanket. When the ink accumulation phenomenon is found, an appropriate amount of the lightening agent should be added to the ink to increase the fluidity of the ink and increase the temperature of the workshop.
(5) The blanket should be thoroughly scrubbed, and it must not be scrubbed only in the corresponding area of ​​the printed graphic. Otherwise, the ink in the unscrubbed area of ​​the blanket may accumulate too much during the printing process, causing the blanket to be crushed when the pressure is applied. In addition, the scrubbing of the back part of the blanket is also very important, because the back mouth is prone to ink squeaking, causing ink to accumulate. If the scrubbing is not clean, not only will the blanket be crushed, but the ink at the mouth of the print will also be Two sheets of paper stick together to affect the quality of the print.
(6) When replacing a larger-sized printing job, pay attention to scrubbing the paper powder remaining on the blanket (from the previous batch of printing jobs), generally scrubbed with a cotton cloth dampened with water to avoid the presence of paper powder. Dip in the ink.
　　 The above content is selected from the 4th issue of “ Printing Technology ·Packaging and Decoration†by Keyin Media in 2012. For more journal content, please pay attention to the journal channel.
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