Use, storage, and remediation of blankets

The quality of blankets directly affects the quality of offset printing, and the use of poor quality rubber blankets or poor storage can also affect the service life. Therefore, it is very important how to properly use and properly keep the blanket.

First, the use of blankets

When the new blanket is cut, it is necessary to align the marking direction of the blanket with the vertical direction of the drum axis. Otherwise, the elongation, thickness, and firmness of the blanket will be changed, which will reduce the service life and affect the product quality. When shearing, dragging and bite cut lines must be parallel. Forces will be uniform throughout the tension, otherwise the pressure will be uneven, the dots will be unclear, and even the liner will wrinkle.

The blanket of the blanket must be narrower than the blanket so that when the blanket is tight, both sides of the blanket can be tightly wrapped around the surface of the drum to prevent impurities, oils, washing liquid, water and other foreign matter from entering the edge of the drum surface. Oxidation rust and blanket delamination blistering.

When tensioning the blanket, care should be taken to eliminate the influence of the back-side frictional resistance. You should not only pull the slightly pulled end tight, but both ends should be pulled. The pull should be consistent with the bite, and the blanket can be tightly wrapped around the drum. .

After the new blanket is installed, the surface of the blanket has a smooth anti-oxidation film, which must be washed off with pumice powder, petrol or kerosene before use to maintain the good ink absorption of the blanket.

In the daily printing, the cleaning blanket must be serious, do not let the ink remain in the pores of the blanket surface, otherwise it will oxidize the dry consolidation film and reduce the ink absorption ability. The conjunctiva on the surface of the blanket can be cleaned with water first, then rubbed with petrol or kerosene and pumice powder, or cleaned with a cleaning agent.

If the blanket has a slight embossing phenomenon, or if the ink transfer performance deteriorates, it can be wiped with a blanket recovery agent, then wiped with water or a damp cloth, and then wiped. This allows the blanket to recover its elasticity and printability.

Second, the blanket storage

Store blankets, avoid contact with oils, acids, alkalis, salts, and chemicals to destroy its elasticity. The blankets are also afraid of light, heat, and damp air. This will make the surface of the blanket sticky, dry, and hardened. Cloth rot and other ills. Therefore, it is best to place it in a closed container or in a well-ventilated place. The indoor temperature is preferably 20°C and the relative humidity is preferably about 70%. If you have already cut a good blanket, it is best to glue the plastic surface of the flat, coated with a layer of talc in the middle, should not add sulfur powder, otherwise it will make the surface too hard and smooth.

The blanket removed from the machine must be cleaned with a cleaning agent or gasoline and stored with a 5% alkaline solution to ensure that it can be used in the future. The surface of the blanket can be saponified and washed with water to remove the saponification product. Apply a layer of talcum powder after drying. When you continue to use it on the machine, you must use the same method as the new blanket to scrub it with petrol, so that the surface will reappear.

Third, blanket remedies

In everyday printing, sometimes the surface of the blanket is sticky. In addition, more or less pieces of paper scraps, impurities, sand, etc. will be brought into the drum, resulting in depression of the blanket or the appearance of small holes on the surface. It must be promptly remedied. The remediation methods are roughly the following:

1. Rubber blanket sticky remedy

The viscose of the blanket is mainly due to poor oil resistance, and the rubber often absorbs a large amount of washing liquid to expand and form. Severe stickiness can completely change the surface properties of the blanket so that it cannot be used. Mild stickiness can also cause the printing paper to adhere to the surface of the blanket, which not only affects the quality of the product, but also makes it difficult to continue printing. Therefore, the blanket should be cleaned in time. It is best to use a solvent with a high volatility to reduce the swelling, and then apply talcum powder or sulfur powder to the surface of the blanket, which has a certain effect.

2. Low-pitched remedies for blankets

During printing, if the blanket is depressed locally and cannot completely transfer the graphic, it is necessary to promptly remedy the low position: generally, the negative side of the blanket is used for replenishment. In order to see the low position, the front side of the blanket can be low. Draw pencils with concave marks on the recesses, and then remove the blanket. Find the appropriate marks on the opposite side of the blanket. Use equal thickness and the appropriate thickness of the paper. The same shape as the mark is used for patching. It is best to use a method of tearing so that the edge of the paper can be trapezoidal. When paste, the glue or glue should not be too thick to avoid forming a hard block after drying. At the same time, the paper should be laid flat. Make up too thick, otherwise it will increase the mutual friction between the printing plate and the blanket, affect the life of the printing plate. If the area of ​​the blanket is low, it can be directly replenished in the pad, but the position of the shimming must be accurate.

3. Cavern eye remedy

The holes on the surface of the blanket can be glued with raw rubber, bovine tendons, plasters, etc., and the blankets are washed before gluing, and then the glue is pulled into thin strips and melted, and the appropriate amount of glue is inserted into the hole. In the eye, after being dried, lightly flatten with a finger or steel sheet to make the surface smooth, and finally paint with talcum powder.