There are many reasons that your printer might be causing black lines on the page....
Inside the printer the paper is moved along by rollers and conveyor belt (transfer belt). this happens when the rollers or the transfer belt inside the printer get dirty.
Dry the glass completely with a clean,dry, lint- free cloth to avoid spots from the glass cleaner.
Sometime printer behave in odd ways than you need to reboot printer. HP recommends that you power your printer on than remove the cord from the back of the printer itself. then unplug the cord from the outlet and wait at least 15 sec. than you can connect the power cord an turn the printer back on
Sometime if you are not correctly instal your printer cartridge,causes black line on page.you need to again reinstall the cartridge in printer.
If your problem not get fix you still getting black line on printed page than you contact your Hp customer services and tell them i have try everything .
What Causes Black Lines on HP Printers?
The answer field is required.