Learn How Your Laser Printer Works

Understanding How Your Laser Printer Works

Posted on February 25, 2010. Filed under: Learn How Your Laser Printer Works |

Laser Printing print sequence

Step 1: cleaning
first the rubber cleaning blade scrapes any toner left on the drum into a used toner receptacle, then a flourescent lamp discharges any charge on the drum (it loses its charge when exposed to light). The EP cartridge is constantly cleaning the drum for a fresh, clear print.

Step 2:charging
the charging corona (a wire or roller) within the EP toner cartridge gets a high voltage from the HVPS (high voltage power supply) to apply a strong, uniform negative charge (-66VDC) to the surface of the drum (the drum looks like a large rolling-pin wo/ handles).

Step 3: Writing
the laser is now on and scans the drum from side to side, flashing on and off reducing the -600 VDC to a slight negative charge (-100VDC) only in the areas it touches based on the information for the print job. Then the pick up roller starts to feed a piece of paper into the printer.

Step 4: Developing
the drum now holds an electrical representation of the image to be printed. The toner is transferred to the areas that were exposed in the writing step. A metallic developing roller inside the EP cartridge acquires a -600 VDC charge from the HVPS. The toner sticks to the magnetic roller. The toner now acquires the charge of the roller (-600VDC). When the toner comes between the developing roller and the drum the toner is attracted to the areas that have been exposed by the laser (with the lesser -100VDC charge). The toner is repelled from the areas that have the same -600VDC charge. The drum now has toner stuck to it where the laser has written.

Step 5: transferring
the controller signals for the paper to be picked up and fed into the machine- as it moves under the drum the image transfers to the paper

Step 6: fusing
then the 350 degree F fuser grabs the paper and melts the polyester resin of th toner making the transfer permanent. The paper continues through the printer and exits. This trips a sensor to start the cleaning cycle (step 1).

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