laser printers Flashcards
laser printer
Combine a laser, high voltage, charged ions,
powdered ink, heat, and paper.
pros: very high quality, fast printing speeds
cons: very complex, many moving parts, requires on printer memory and messy inside
imaging drum
Image is drawn onto a photosensitive drum
Picks up toner - Transfers toner to the paper
Can be separate from the toner cartridge or combined
fuser assembly
Heat and pressure - Melt plastic toner powder
Permanently bond toner to paper
Transfer belt and roller
Color laser printers. CYMB
Four separate toner cartridges
Image is transferred from all cartridges to the single belt and then to a single transfer roller
Pickup rollers
Pickup paper - Should be a single page at a time
Problems if no paper is picked up or multiple sheets are picked
Should be periodically cleaned or replaced
Separation pad
Pull just the top sheet from the paper tray
Not multiple sheets
Small and inexpensive - Easy to clean or replace
Duplexing assembly
Printers usually print on a single side not both sides simultaneously
Printing on both sides is a two step process
You need mechanisms to “flip” the page automatically
Can be built-in to the printer or available as an add-on
laser printing steps
- processing 2. charging 3. exposing 4. developing 5. transferring 6. fusing 7. cleaning
Processing
build the entire page in memory
Charging
prepare the drum with a negative electrostatic charge
Exposing
write the image with the laser
Developing
add toner to the charged areas of the imaging drum to the paper
Fusing
heat and pressure
Cleaning
remove excess toner
Replacing the toner cartridge
Look for the messages
– Low doesn’t mean empty
The toner can also contain the OPC (Organic Photoconductor) drum
Power down printer and remove packing strips from the new drum and replace it with the old
