Printer Technologies Flashcards
Laser Printing Process - 6 Stages
Cleaning Charging Exposing Developing Transferring Fusing
Laser Printing Process - Stage Description
A physical and electrical process cleans the previous image off the photosensitive drum.
Excess toner is scraped off the drum by a rubber cleaning blade into a debris cavity called a hopper. Some printers use a wire with AC voltage to remove the charge from the drum surface, which allows the excess toner to drop off the drum into the hopper.
Lubrication is applied to the heat roller to ensure an even transfer of the next image.
Cleaning
Laser Printing Process - Stage Description
The primary corona wire applies a negative charge to the photosensitive drum as the surface of the drum rolls across the surface of the conditioning roller. This removes any electrical charges that might remain from the previous print image.
Charging
Laser Printing Process - Stage Description
The laser projects the image on the photosensitive drum. Where the light hits the drum, the negative charge is dissipated to the grounded center of the drum. This results in areas with a lower negative charge than the rest of the drum. These areas create an electrical image of the print data on the surface of the drum.
Exposing
Laser Printing Process - Stage Description
The drum passes by a developing roller covered in toner. The toner is a negatively-charged combination of plastic and metal particles. Areas of the drum where the laser hits lose their electrical charge, this attracts the negatively charged toner from the control blade of the roller. Areas on the drum that still have a negative charge repel the toner. This creates a mirror image of what is to be printed in toner on the drum.
Developing
Laser Printing Process - Stage Description
Pickup rollers grab a single sheet of paper from the paper tray or manual feed slot and move it into the printer. A separator pad (commonly two or three inches wide) placed in the middle of the paper path keeps the pick up to one paper at a time. Once the paper moves into the printer, it receives a positive charge as it passes through the secondary corona wire or transfer roller. The negatively charged toner is attracted to the positively charged paper and transfers from the drum to the paper.
Transferring
Laser Printing Process - Stage Description
The paper passes through a set of rollers that apply heat and uniform pressure to the paper and toner, curing the image onto the paper. As the paper passes by a static eliminator strip, it neutralizes any remaining electrical charges on the paper. This prevents the paper from jamming in other areas of the printer.
Fusing
