How to properly use ContiTech air cushion blanket
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First, the use of blankets
1 The characteristics of the blanket and how to set the thickness of the lining?
"Condit" blanket is the third generation of blanket invented in the 1990s. It is a closed rubber particle that is evenly added to make the internal pressure higher than the printing pressure during the rubber vulcanization process. Under the pressure of printing, the closed type The rubber inside only changes the shape and volume, and there is no inhalation and exhaust process, which can satisfy the high-speed printing and the abnormal pressure from abnormal conditions within a certain limit, so that not only can the dot reduction be clear, The purpose is to enable most of the small area printing to change the printing area without changing the blanket.
Because the air cushion of the "Candy" air cushion blanket is good, the coefficient of the subsidence of the blanket is 0.05mm-0.1mm less than that of other brands. The sag coefficient is the difference between the thickness of the blanket before printing and the thickness after printing. Value) This way, if you use another brand of blanket to replace the "Condit" blanket, you should consider this difference in the calculation of the lining (refer to the PS roller and blanket cylinder and the blanket and impression cylinder). In the case of inter-pressure), because the requirement of the blanket for the lining is within the error range of 0.015 mm, otherwise, the overpressure generated by it is far from 0.05-0.1 mm, which causes the dot to expand, and the small-area printing cannot be changed. Area, blanket is not easy to clean and so on.
2 the choice of gun bottom paper?
With the development of society and printing technology, the selection of special floor paper for blankets is more and more extensive, because not only the thickness of each ordinary coated paper has an error of 0.01 mm-0.02 mm, but also varies with temperature and humidity. When the temperature is different at different times and under different climatic conditions, the superposition of multiple ordinary coated papers causes a very large error. You only need to test the total thickness of the paper before the machine is within 0.02mm error range to meet your printing requirements or use special gun base paper.
3 withdraw the lining under the condition of ensuring printing pressure
Since the printing press can adjust the printing pressure according to different paper thicknesses, the distance between the impression cylinder and the blanket cylinder is adjustable. The distance between the blanket cylinder and the PS cylinder is no longer changed after the equipment is installed. The pressure between them is provided by the machine manufacturer, because the manufacturer will design the rubber in the roller and PS. The pressure between the plate cylinders is set on the PS plate cylinder so that the blanket cylinder only needs to pad the blanket to the level of the roller. (Because in the printing, the rubber will produce a rubber compression coefficient after 20 weeks of rotation, so when installing a new blanket, the general high dry roller is 0.05mm).
"Condit" blanket has good elasticity and small compression coefficient. Generally, the new blanket thickness is 1.95 or 1.69mm, and the compression coefficient is about 0.04mm. The actual thickness of some blankets is only 1.88 or 1.61mm. We are guaranteeing the blanket cylinder. In the case of the cylinder pressure of the PS plate, the thickness difference between different brands of blankets is reasonably considered to calculate the thickness of the package to achieve perfect printing.
Attachment: Thickness of lining when using Conti blankets for various types of printing presses (Reference)
Printing machine model
Lining thickness
Printing machine model
Lining 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 film is used)
Heidelberg GTO52
105 silk
For other unprinted printer models, the thickness of the lining when using other brands of blankets is reduced by 5 filaments.
Second, the maintenance and maintenance of the blanket
1 overpressure
The replacement of the blanket is caused by an abnormal factor. (ie: a small area can not be changed to a large area, not easy to clean and very paper folds, double sheets, pulp)
Germany "Condit" air cushion blanket is a new type of third-generation product. It can have enough air cushion reduction performance to overcome some of the problems within a certain limit. When overpressure occurs, the total thickness does not exceed 0.50mm. As long as the surface of the blanket is not broken, you can do the following:
Continuous printing of 12 sheets of paper can be automatically restored. Otherwise, after replacing the liner or the bottom paper, the 22 sheets of paper can be restored, while other brands are generally around 0.20mm-0.30mm. If the problem still occurs, please Your experience to adjust the use.
2 cleaning
We recommend that users clean the blanket with the following steps:
1. Wipe off water-soluble substances such as paper powder using warm water.
2. Use a car wash water or solvent that does not damage the blanket to remove substances such as ink dissolved in the solvent.
3. If there is calcium and magnesium ion deposition on the surface of the rubber market, it may be washed with citric acid-containing car wash water or weak acid such as vinegar.
Third, the impact of the surface finish of the blanket on the reduction rate of the dot
1"Condit" special surface processing technology
The blanket has a high surface finish and a small dot enlargement rate during printing. Since the surface of the "Conduit" blanket has been coated and precision grounded by up to 6-7 passes during processing, the blankets for sheetfed offset presses and thermoset rotations have a surface finish of 5-6 um. In the printing process, the enlargement rate of the printing dots is greatly reduced, and the printing products capable of adapting to the requirements of extremely high dot sizes can be adapted. (UV Black has a large dot enlargement rate due to its special natural rubber composition.)
2" Kangda" air-cushion blankets are evenly changed in the number of layers of each dot due to their special surface rubber properties and perfect compressibility. Especially in the four- to eight-layer network, the dot enlargement rate is not abrupt. A smooth curve, the minimum dot expansion rate between the four layers to the eight-layer network can be between 12%, so that the contrast of the printed layer can be very well expressed.
Fourth, the review
In summary, in different printings, the rubber sheets are different, and the compressibility and surface characteristics of the air cushion affect the printing suitability. Different air cushions and surface finishes have different requirements in different printing. . Therefore, the principle of the German "Condit" company is that there is no best blanket and only the most suitable blanket. The printer selects the blanket according to different printing methods, substrates and other related materials.