Line appearing on prints - Samsung CLX-3170FN All-In-One Laser Printer

There are two possible things that can make such a problem:
1.The drum of the toner cartridge had and his life.If you take out the cartridge,turn it around and you will see a big metal roller.The color of the drum should be all the sime all over the drum.If there are brown line around the drum thats mean it it time to change the drum of the cartridge.
2.The PCR(Primary charging roller) could be damage.The PCR is located in the toner catridge and youu need to take apart the cartridge to see the PCR.To do that you may need a proffesional help.

Being the drum there is a box that collects the surplus ink.
De to designed obsolescence it fills up before the drum is worn out.
When it fills up the lines appears.
You can empty it by removing the drum and using a vacum cleaner (bagless type with good filter only ! ie dyson)
Did it : works
You could also try to drill a hole in the box to empty it
yet to try potentially less messy and easier