The output of the printing paper becomes black

　　The output of the printing paper becomes black

For the needle-type printer, the cause of the fault is the ribbon hair removal, ink on the ribbon too much, print head dirty, color band quality and putting position too close.

Overhaul should first adjust the position of putt, such as failure can not be excluded, and then replace the ribbon, cleaning the print head, generally can be ruled out.

For inkjet printers, should focus on whether the nozzle damage, ink pipe is broken, ink model is normal.

For laser printers, most are due to corona discharge wire failure or control circuit failure, so that the laser has been launched.

Causes the printout content to be completely black. Therefore, it is necessary to check whether the corona discharge wire has been disconnected or whether the corona high pressure exists, and whether the beam detector in the laser beam path is working properly.