HP d640 HP D640 High-Volume Printer - User Manual (Printer and Accessories), C - Page 183

Managing Consumables Recycling Printers that user powdered toner generally only transfer about 70 to 80% of the toner used for a page image to the paper. The remaining 20 to 30% is known as waste toner because in most printers it is thrown away. In a printer that uses a toner cartridge, the waste toner is never seen because it is moved to a waste area inside the print cartridge. The D640 printer is unique in the industry, providing the choice of recycling the waste toner or throwing it away. As the printer ships from the factory, the toner recycling mode is disabled and waste toner collects in a bottle. You remove and throw out this bottle each time you add a new bottle of toner. With toner recycling enabled, the waste toner is funneled back into the toner hopper and gradually mixed with new toner. The disadvantage to recycling toner is a possible slight reduction in print quality. Print may appear lighter and small voids may be visible in dark images. In most text applications, you will probably not notice any reduced print quality with recycling on. If your application requires the best possible print quality, do not use toner recycling. Unlike Density and Economode, the effects of toner recycling are not immediately noticeable when you stop recycling. The waste toner must be completely flushed from the toner path. Depending on how long the recycling feature was used, it might take up to five bottles of new toner before the waste toner is completely flushed from the system. Toner Recycling Switch Toner recycling is enabled or disabled by moving the plastic slide switch located directly over the toner collector bottle. When it is pushed to the right, toner is recycled. When it is pushed to the left, waste toner collects in the toner collector bottle for disposal. Figure 6-2 shows the bottle and switch location. 6-8 Advanced Topics