Cleaning during offset printing (2)

Blanket cleaning

Cleaning blankets commonly used materials are water, gasoline, kerosene, pumice, sulfur powder, talcum powder, rubber blanket cleaning agent, blanket reductant.

First, the new blanket cleaning

1. There is a protective film on the surface of the new blanket. Therefore, before using a new blanket, the protective film must be removed. Otherwise, the ink absorption of the blanket will be affected.

2. Pouring a proper amount of kerosene on the blanket or pouring the kerosene onto a cloth.

3. Spread pumice powder on the blanket or pumice powder with a kerosene wipe.

4. Repeatedly wipe the blanket.

5. Pour gasoline and clean pumice powder with a cloth.

6. Wipe the blanket clean with a dry cloth.

7. Wrap talcum powder with 2-3 cotton gauze and apply talc evenly over the surface of the blanket.

Second, the daily cleaning of the blanket

In the daily printing process, the blanket is constantly in contact with the ink and the paper, and the ink on the printing plate graphic is transferred to the paper, so that the ink, paper hair, and paper powder are inevitably adhered to the blanket (paper Filler) and other substances. This adhesion phenomenon is more serious when the blanket is sticky, printed with inferior paper, or the pigment used in the ink is coarse, with a large specific gravity and a low viscosity. Therefore, during the printing process, the rubber should be visually recognized. Cloth surface accumulation and different job requirements. Regular cleaning of the blanket ensures and enhances the clarity of the graphic and extends the life of the blanket.

1. Prepare the materials used for cleaning and prepare a piece of water, a cloth, and a dry cloth.

2. The grip of the cloth is the same as that when it is wiped.

3. Jog the machine or make the machine run at a low speed, wipe the water from the mouth of the blanket until it is slightly stretched.

4. Jog the machine from the blanket's drag to the mouth or when the machine is running to the mouthwash. Wipe the blanket with gasoline to dissolve the ink on the blanket.

5. When jogging the machine or when the machine is re-run to the mouthwash, use a clean cloth to remove grease and impurities from the surface of the blanket.

Third, the special cleaning blanket

If the blanket is used for too long or because of improper maintenance, a smooth film or stickiness will form on the surface of the blanket, which will not only affect the clarity of the printed text, but also cause the printing work to not proceed smoothly. Therefore, it is necessary to wash off the smooth film layer or to stick the blanket for processing.

1. Treatment of blanket smoothing film: remove the blanket together with the splint from the machine and place it on a flat surface with the same cleaning method as the new blanket; or wash it on the machine with water. Wipe with pumice powder with petrol.

2. Sticky remedy for rubber blankets: The blankets are sticky, mainly due to their poor durability and swelling or aging of the blanket. Severe stickiness will cause the blanket to continue to be used. Mild stickiness will also cause the printing paper to adhere to the blanket. Therefore, stickiness should be detected as soon as possible and the blanket should be cleaned in time.

3. The cleaning method is: first use gasoline to wash off the ink layer on the surface of the blanket, wipe it with a dry cloth, and then use volatile solvent gasoline or a small amount of industrial alcohol in gasoline (also can use rubber reducer ) Wipe the blanket, then use talcum powder to mix sulfur powder to wipe the surface of the blanket and reduce the stickiness of the blanket.

Fourth, prone problems and precautions:

1. When pumice powder is used, it must be ensured that the pumice stone does not contact the plate or fall into the underlay, otherwise it will accelerate the wear of the corresponding part of the plate.

2. The interval between daily cleaning of the blankets should be based on the blanket accumulation and different job requirements. The general rule is: when changing the color, it must be cleaned once; for regular printing, about 3000-5000 sheets should be cleaned once; Every day before work (after shut-down) should be cleaned once; the test printing process should be cleaned at least once.

3. The fingers should be light when jogging the machine. At this time, the hand holding the blanket should leave the surface of the drum; after the jog is completed, the finger should leave the button during the scrubbing process.

4. When cleaning, avoid contact with solvents such as gasoline on both sides of the blanket.

5. The liner that is lined with the blanket should be narrower than the blanket to prevent the penetration of solvents such as gasoline.

6. Spare or unused blankets should be cleaned, talc powder on, covered with protective paper, stored in a closed container or a well-ventilated, cool, dry place, avoid oil, acid, alkali, salt And other chemicals come in contact and avoid being squeezed. When printing on the machine, it must be cleaned like a new blanket.

7. Kerosene should not be used when cleaning the blanket daily.

8. When using a device that automatically cleans the blanket, strictly control the amount of cleaning agent.