Printing environment humid, high temperature; The printer is placed skew, uneven, toner ink powder inhomogeneity; The scanning window of the printer is not clean; Cartridges are damaged.As the printer cartridge is special, once the cartridge damage, the best way is to directly replace the cartridge. EBY brand cartridges are cheap, practical and high, will not damage the printer, I use the brand is EBY toner cartridges, it is recommended to use.