1. How to use the blanket
â‘ The characteristics of the blanket and how to set the thickness of the lining?
"Kangdi" blanket is the third generation of blankets invented in the 1990s. During the rubber vulcanization process, evenly-closed rubber particles that make the internal pressure higher than the printed external pressure are evenly added, so that under the pressure of printing, the closed type The inside of the rubber only changes the shape and volume, and there is no process of suction and exhaust. It can be satisfied with high-speed printing and overpressure from abnormal conditions within a certain limit, so that it can not only make the dots clear, The purpose is to make most of the small area printing in the large area printing without changing the blanket.
Because of the good elasticity of the air cushion of "Kangdi" air cushion blanket, the sag coefficient of the blanket is 0.05mm-0.1mm less than that of other brands (the sag coefficient refers to: the difference between the thickness of the blanket before printing and the thickness after printing) Value) In this way, if you use another brand of blankets to replace "Kangdi" blankets, this difference should be considered in the calculation of the lining, (refers to the guarantee between the PS cylinder and the blanket cylinder and the blanket and the impression cylinder In the case of pressure) because the blanket's requirement for the lining is within the error range of 0.015mm, otherwise, the overpressure it generates is far from 0.05-0.1mm, which causes the dot to expand and cannot be changed when printing in a small area. The area and the blanket are not easy to clean.
â‘¡Selection of gun bottom paper?
With the development of society and printing technology, the choice of blanket special ground paper is more and more widely used, because not only the thickness of each common coated paper has an error of 0.01 mm-0.02 mm, but also changes with the change of temperature and humidity At different times and under different climatic conditions, the error caused by the superposition of multiple sheets of common coated paper is very large. You only need to test whether the total thickness of the paper is within 0.02mm error range before you start the machine, to meet your printing requirements or choose a special gun bottom paper.
â‘¢Under the condition of ensuring printing pressure, remove the bag liner
Because the printing press can adjust the book printing pressure according to different paper thicknesses, that is, the distance between the impression cylinder and the blanket cylinder is adjustable. The distance between the blanket cylinder and the PS version cylinder will not change after the equipment is installed. The pressure between them is provided by the machine manufacturer, because the manufacturer will design the rubber between the cylinder and the PS The pressure between the plate cylinders is set on the PS plate cylinder, so that the blanket cylinder only needs to be level with the blanket during printing. (Because in printing, the rubber collapse coefficient will be produced after 20 revolutions of the blanket, so when installing a new blanket, the general height of the dry pillow is 0.05mm).
"Kangdi" blankets have good elasticity and a low deflation coefficient. Generally, the thickness of new blankets is 1.95 or 1.69mm. The deflation coefficient is about 0.04mm, and some blankets are only 1.88 or 1.61mm thick. In the case of the pressure of the PS version of the cylinder, the thickness difference between different brands of blankets is reasonably considered to calculate the thickness of the package to achieve a perfect printing.
Attachment: Thickness of various types of printing machines when using Condi blanket (reference)
Printing machine model
Packing thickness
Printing machine model
Packing thickness
Heidelberg 102V / CD102V
35 silk
Roland 700
65-68 silk
Heidelberg SM74 / 72
35 silk
Komori 40
85 silk
Heidelberg SM52
100 silk
Mitsubishi 3F / IF
40 filaments (neutral) / 50 filaments (when no bottom film is used)
Heidelberg GTO52
105 silk
For other types of printers not listed, the thickness of the liner when the normal use of other brands of blankets is normally subtracted by 5 threads.
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Second, the maintenance and repair of the blanket
â‘ Overpressure
The replacement of the blanket is caused by abnormal factors. (Ie: small area can not be changed to large area, not easy to clean and very paper corner, double sheets, pulp block)
The German "Kangdi" air cushion blanket is a new type of third-generation product. Within certain limits, it can have enough air cushion reduction performance to overcome some of these problems. When overpressure occurs, the total thickness does not exceed 0.50mm. As long as the surface of the blanket is not broken, you can operate as follows:
Continuous printing of 12 sheets of paper can automatically recover, otherwise it can be restored after stopping to replace the liner or gun bottom paper, and then printing 22 sheets of paper, and other brands are generally around 0.20mm-0.30mm. If the problem still occurs, please refer to Use your experience to adjust the use.
â‘¡Cleaning We recommend users to use the following steps to clean the blanket:
1. Use warm water to wipe off water-soluble substances such as paper powder.
2. Use car wash water or solvents that do not damage the blanket to wipe off ink and other substances dissolved in the solvent.
3. If there are calcium and magnesium ions deposited on the surface of the rubber city, you can use car wash water containing citric acid or weak acid substances such as vinegar for cleaning.
3. The effect of the surface finish of the blanket on the dot reduction rate
â‘ "Kangdi" special surface processing technology, the surface finish of the blanket is high, and the dot expansion rate is small during printing. Because the surface of "Kangdi" blanket has been coated and precision ground for up to 6-7 passes during processing, it is suitable for sheet-fed offset presses and heat-set rotary blankets with a surface finish of 5-6um. In the printing process, the expansion rate of printing dots is greatly reduced, and it can adapt to the prints with extremely high dot requirements. (Because the surface of UV Black is a special natural rubber composition, the expansion rate of the network is relatively large.)
â‘¡ "Kangda" air cushion rubber cloth has a uniform change in the number of layers of each dot due to its special surface rubber characteristics and perfect compressibility, especially between four to eight layers of mesh, the dot expansion rate is not abrupt. A smooth curve, the minimum dot expansion rate between four to eight layers of mesh can be between 12%, so that it can very well show the contrast of the layered sense of the printed product.
4. Overview
In summary, in different printing, the requirements for the blanket are different. The compressibility and surface characteristics of the air cushion affect the printability. Different air cushions and surface finishes have different requirements in different printing . Therefore, the principle of the German "Kangdi" company is that there is no best blanket but only the most suitable blanket. The printer chooses the blanket according to different printing methods, substrates and other related materials.
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