In the offset printing process, particularly in monochrome printing machines, whether it's four-color printing (Y, M, C, BK) or for trademarks and packaging, ink washing and color changes are often necessary. This involves cleaning the entire inking system and replacing the old ink with new ink. The ink washer typically consists of a rubber blade, an ink collection tray, and an adjustable screw.
The ink washing procedure begins by applying gasoline or car wash water onto the ink rollers. The wiper is then installed into the designated slot, and the adjusting screw is tightened so that the rubber blade makes contact with the ink roller at a 40° angle. As the machine runs, the tandem rollers move back and forth, scraping away the old ink and solvent mixture through the rubber blade into the ink collection tray.
Proper ink washing and color change are essential for achieving accurate color reproduction. If not done thoroughly, the ink color may appear dull or inaccurate. To ensure effective results, several key steps should be followed:
1. The ink scraper must be properly installed on the printing press when changing ink or cleaning the ink rollers due to other reasons. The eccentric pins of the ink collection tray should be placed into the groove on the support shaft, while the adjusting nut is fixed into the square iron block’s opening. Once installed, start the press and adjust the nut so that the rubber blade gently touches the ink roller. Ensure even pressure on both sides for full contact and complete ink removal.
2. When cleaning, pour gasoline over the ink roller near the ink fountain area from above. This helps loosen and remove all accumulated ink and residue. The waste ink will flow into the ink collection tray from the edge of the rubber blade. After some time, the ink roller should be clean.
3. After cleaning the ink fountains and rollers, wipe them using a soft, lint-free cloth with good absorbency to ensure no residue remains.
4. The wiper must be positioned accurately, ensuring equal distance and consistent pressure between the rubber blade and the ink roller surface.
5. After cleaning, wipe firmly and quickly, making sure the cloth does not get caught in the rotating ink rollers during operation.
6. When pouring gasoline, the operator should maintain a controlled amount to avoid splashing and potential hazards.
7. Smoking and open flames are strictly prohibited in the workshop to prevent fire risks during ink washing and color changes.
8. Safety is crucial during the operation. Operators must be cautious of their clothing, hands, and any loose items like keys or pens that could fall into the ink rollers.
9. There are two common scenarios during ink washing and color change: switching from light to dark ink, or dark to light ink.
- **Changing Light Ink to Dark Ink**: This is generally easier and less time-consuming. First, remove the light-colored ink from the ink fountain using an ink shovel, then use the wiper to clean the ink roller. Remove any debris such as ink skins or paper fibers left behind.
- **Changing Dark Ink to Light Ink**: This requires more thorough cleaning. Since dark ink can leave residual stains, the ink roller must be cleaned meticulously. All parts—ink fountain, ink roller, and tools—should be cleaned. Apply the light ink using the ink shovel, run the press to spread the ink evenly, and then rinse with gasoline. Repeat if necessary until the roller is completely clean.
By following these procedures carefully, printers can ensure high-quality output and minimize color inaccuracies caused by improper cleaning.
TV Stand
TV stand is a piece of furniture designed to support and display a television set. It is commonly used to hold the TV at a comfortable viewing height, provide stability, and offer storage space for related devices and accessories.
TV stands come in various styles, sizes, and materials to accommodate different preferences and room décors. Some common types include:
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Entertainment Center: These are larger TV stands that typically encompass multiple shelves, cabinets, and drawers. They can hold not only the TV but also audio/video components, gaming consoles, DVDs, and other media.
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Console Stand: Console stands are sleek and minimalistic, designed to hold the TV on top while providing a couple of shelves or compartments below for basic storage needs. They are often made of wood, metal, or a combination of both.
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Wall-Mounted Stand: These are not traditional stands but rather wall-mounted brackets or shelves that securely hold the TV on the wall. They are ideal for saving space and creating a clean, modern look. Wall-mounted stands may have adjustable features for swiveling or tilting the TV.
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Corner Stand: Corner TV stands are specifically designed to fit in the corner of a room. They have a triangular or wedge-shaped design to maximize space utilization while providing storage options.
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