Printed copies come out with discolored lines throught the page

SOURCE: Black line along page in copy and scan modes,not in print mode

Your scanner lamp is dirty. Take apart the scanner glass and clean the lamp. (Look for contaminated spots on the scanner lamp).

SOURCE: lines across printed page

try to locate the print head of the unit. you will see a mirror there. clean the mirror maybe it has some foreign object.

SOURCE: cleaning a streck that appears on printed pages

it also may be the fuser

SOURCE: repeating wide smudgy horizintal line across my printed pages

I had the same problem, replaced the PCR in the cartridge, the small black drum that pre charges the drum and erase the old image.
After that print was all back ok.

Regards

SOURCE: Unwanted Horizontal lines across the printed page

this is definetelyh a toner cartridge problem. Replace the cartridge and the problem will stop. I doubt this is a fuser problem.