Is that they create a dangerous gas called ozone (a negative DC current twenty times the ozone produces produced by a positive current). The problem with using Corona Wires, particularly negative DC Corona Wires,

The corona results in a uniform minus six-thousand DC volt charge on the screen that smooths the resultant charge before it reaches the drum surface (-6KVDC). Separating the wire from the drum is a varistor grid drum. This ionizes the air around the wire, creating a corona effect. Minus six-thousand volts DC (-6KVDC) are sent through the wire, which has no ground. Corona Wires work by ionizing the air adjacent to them. In newer printers, it is accomplished by a Primary Charge Roller. In older printers, this was done by a Primary Corona Wire. Later development introduced Primary Charge Rollers (PCRS) that combine electrostatic cleaning with conditioning and eliminate the need for Erase Lamps.Ĭonditioning - Before any image can be produced, the OPC must be conditioned so that a uniform negative charge can be given to the drum. This effectively grounded the drum surface in that area, discharging it uniformly and destroying any latent image. Erasure was accomplished by focusing incandescent light through red filters onto the drum in the area just past the Cleaning Blade. Cleaning - In older printers, cleaning required two steps: (1) Toner left on the drum from the last transference was wiped off by a Cleaning Blade and (2), the remaining electrostatic image had to be erased.

Copier laser printer