Cleaning during offset printing (below)

Water roller and water roller (water roller type) cleaning

In the printing process, due to the repeated contact between the water roller and the printing plate, after a period of time, the ink and other impurities will be detached from the printing plate on the one hand, and the velvet structure on the surface of the water roller will be damaged. In the process of transferring water, the surface velvet structure of the roller will be subject to the same damage; at the same time, the ink on the water roller will be transmitted to the water transfer roller through the hydrophobic roller. Therefore, the water roller fleece must be cleaned or replaced in time to restore and maintain water absorption and water transfer performance.

First, prepare cleaning materials and tools

1. Cleaning materials: gasoline, water (preferably a pool with a tap);

2. Tool nylon brush and steel sheet.

Second, cleaning

Put both ends of the removed water roller on the bracket (or wooden pillow) of the water roller, pour the gasoline on the roller surface, and use the plate brush to brush evenly in one direction (the direction of the silk of the water roller velvet); After the ink is dissolved, it is flushed with water until the roller surface is free of dissolved ink. Finally, the excess moisture is scraped off with steel.

Water bucket and water roller cleaning

The more common water roller is chrome plated. In the printing process, the ink stain on the water roller is also transmitted to the hydrophobic roller and the roller roller, which reduces the water transfer. In addition, when the downtime is long, even if the fountain roller and the fountain roller are not contaminated by ink, an oxide film is formed on the surface, and the surface of the roller absorbs oil mist and other impurities in the air, so that they are Some hydrophilic properties have changed. Therefore, the bucket roller and the squeegee roller must be cleaned in a timely and regular manner so as to restore its hydrophilicity and uniform water transfer.

Cleaning materials: pumice powder, fountain solution, glue, and wipes.

1. Draw the dampening stock solution, and then pumice powder, and then rub it back and forth on the surface of the hydrophobic roller and the fountain roller. When the ink and oxide film are removed, quickly wipe the surface with a wet cloth.

2. Jog the machine, go to the remaining undisturbed part, and wipe it according to the appeal method until all the two rollers are cleaned.

3. Use a water cloth to pick up the glue and wipe the surface of the roller.

Water bucket cleaning

Bucket is generally made of copper alloy material. The long-term use of the bucket will inevitably fall into the dust and other debris. At the same time, the bucket roller will also bring paper powder, paper hair, and ink stains into the bucket. This will not only reduce the wetting property of the fountain solution. , And will directly affect the printing quality of printed products.

Cleaning steps

1. Prepare fresh water and a cloth, a brush, and a plastic tube.

2. Remove the fountain roller

3. Pour the water into the bucket and use a brush to stir up the contents of the bottom of the bucket. Then use the tubing (the principle of the connected device) to suck the turbid liquid out of the water. While watering, brushing and guiding the water until the bucket is basically clean, the bucket is thoroughly cleaned with a cloth.

4. Install the fountain roller

Easy problems and precautions

1. Take care when disassembling the water roller. If the disassembled water roller does not need to be used or installed immediately, it should be placed on the water roller bracket.

2. When cleaning the water transfer roller and the water roller, the direction of the brush and the scraper should be consistent with the direction of the silk roller of the water roller velvet.

3. When cleaning the fountain roller and the hydrophobic roller, the amount of pumice powder should be as little as possible, and pumice powder should be avoided from falling into the surface of the bucket or the water roller.

4. The water roller should be cleaned in time, otherwise it will reduce the water delivery performance of water delivery components, resulting in the production of dirty plates and other ills. The time for cleaning the water roller and the water bucket should be determined by the degree of fouling and the specific conditions. The general rule is:

1) When stopping for a long time or changing fine products, clean the water roller and the water bucket thoroughly before turning on the machine.

2) During the normal printing process, if the ink layer of the layout is thick, the water roller should be cleaned every day; if the layout graphic is thin or the general product is printed, the cleaning frequency can be appropriately reduced.

3) The ink stains on the water roller and the water roller should be cleaned in time, otherwise the local water supply of the printing plate will be insufficient, resulting in the failure of the dirty plate and the like. At the same time, the water roller may be easily stained with ink.

4) When replacing dark ink with light ink, be sure to clean or replace the water roller.

5) Before the new water roller is printed on the machine, apply a clean, wet cloth to wipe gently in the direction of the ridge of the water roller velvet to remove floating fluff on the surface of the water roller. Then, wipe the surface of the water roller with a suitable amount of water or dampening solution with a water wiper, so that the new water roller has a certain amount of water before the machine is on, so as to facilitate printing. The new water roll on the machine, you can make the machine idling for 10 ~ 20min, in order to make up for the water content of the water roller, and then shut down to wipe off the fluff on the water roller and the roller roller.

Ink fountain and ink path cleaning

Ink fountain cleaning:

1. Prepare ink knives, containers for remaining ink, petrol, and two wipes

2. Scooping: Use the ink knife to shovel out the ink in the ink fountain.

3. Remove the ink fountain

4. Clean the ink fountain roller: Use a cloth to pick up the gasoline, scrub the ink on the ink fountain roller, and completely dissolve the ink. Then wipe the ink fountain cleanly with a clean cloth to make it look shiny.

5. Cleaning ink fountain