1,  shop roll drum itself failures caused by the failure of the abnormal sound; 2, the printed product appears: bottom ash, black side, the black stripe, white bars and other issues that affect print quality; (caused by the toner will run out IOUs not covered under warranty inside, when there is color, simply remove the cartridge from the machine, horizontal shake a few times, and then into the machine, or also the normal printing a few pages, indicating that the toner is about to run out, such as playing large white pages, indicating that carbon powder has been completely exhausted) two, the warranty period: the company produces quality guarantee period is one cartridge life cycle; (that came with the drum toner runs out) Third, the user process using our products, if the product of the following conditions, the Company does not assume warranty obligations; 1, privately torn or damaged friable affixed with the company seal paper; 2, associated with the use of stickers or sticky paper, resulting in a clear plastic drum marks or scars; 3. obviously artificial drum surface scratches, scratches or damage or foreign matter falls traces; 4, a significant fall drum surface, traces of collision; 5, the seal has been pulled, but no print quality problems; 6, the drum shell rupture, recycled powder, drum shell holes destroy the original structure, the drum shell fall apart; 7, toner is about to run out; cartridges use a little common sense, install, and remove the cartridge, the printer should be first off. 2, the new cartridge into the printer, you should jiggle a few, so loose and uniform toner to ensure print quality. 3, avoid direct contact with the photosensitive drum core of light, do not touch the photosensitive drum core. 4, the toner will be exhausted, print handwriting is no longer clear and uniform, remove the cartridge jiggle a few, you can continue to print dozens of pages. 5, in order to avoid affecting the normal office, the user should keep a new toner cartridge. 6, selenium should be properly used empty packing placed to avoid polluting the environment.