There are many different suppliers of digital colour copy machines on the market, and each model functions differently. Enclosed is a general discription of the digital copy method.
Digital Colour Copying – How does it work in general?
1. Negative charge (500V-700V) is deposited on the surface of the photo-conductive drum
2. Image is converted into a rasterised laser or LED image
3. Exposed areas become conductive and lose their charge
4. Toner particles are charged and deposited on the image areas of the drum
5. Paper is charged and the oppositely charged image transfers from the drum
6. Toner is fused onto the paper
7. Residual charge on the photo-conductive drum is neutralised by exposure to light - excess toner is mechanical removed.
There are specific demands on paper used in digital colour copying machines. A paper designed for colour copying must have the correct electric charge acceptance and decay behaviour. This is the requirement to obtain good images on the substrate. The moisture content of the paper has to be adjusted, if the paper is too dry, it has poor electrical properties and it will have problems in finishing and converting step afterwards. If the paper is too moist, the electrical resistance too low, and you will run into dimensional stability problems after fusing.
Storage and handling of silver image The relative humidity of silver image is much lower than that of the surrounding air at around 35%. The moistureproof wrapping should be kept on the reams until just prior to printing otherwise moisture absorption could lead to printing problems. The ideal storage temperature is between 19ºC and 23ºC. Store away from extremes of temperature, humidity and direct sunlight. Store opened reams in their original moisture-proof wrappers in-between usage to avoid moisture take-up. Care must be taken not to damage the edges of the sheets when unwrapping and loading the printer.
