My canon ir4570 has been working fine till now. Black streaks appear at the bottom of the page. How can I get rid of the black streaks?

Check for white-out or some other dirt on the scanner head, the piece that moves from top to bottom to scan the item to be copied.

The drum has been scratched by a paper jam. Needs replacing to eliminate those marks.

I suggest You Go to Official Canon Printer Page For You Canon Problem On Below Canon Page URL:
Copy Has Vertical Black Streaks In Case You Still face Problem and Need Online Assistance Then Please Follow Us For On : Canon Printer Support

They are manny cause of black copy.
1.over tone.
2.arching on main charger or dirt on main charger.
In Case You Still face Problem and Need Online Assistance Then Please Follow Us For On : Brother Printer Support

sounds like your cartridge is leaking. I'd try replacing the cartridge

There should not be a thick black line at the bottom, but could be from several things, light coming in from somewhere is my first guess, toner is almost out or the ribbon is getting stuck on the inside at that point. You may have to call Cannon and ask them.

first check the nozzle (bottom of cartridge). if u dont see black spots around the nozzle line (many nozzle that form straight line, black long straight line, color, 3 short line), or a view of burnt, u can continue below.

blow the air hole till it drop the ink. then clean it with water. but note, dont wipe the nozzle, let them wet. u must wipe the contact with dry tissue before inserting it back.

otherwise, u must replace ur cartridge :D

Do the streaks appear when you use the contact glass or just when you use the Automatic feeder?
If both, then you need to replace either the (drum unit) or the fuser roller(s).
If it just happens through the auto feeder, then lift up the "feed-in section" (left side) and clean the narrow scanner glass.

I just sprayed windex on bottom of cartridge several times and wiped with paper towel until dark streak of black appeared. Then I dried off cartridge and replaced. It works now. Must have been clogged.

if you need any parts for that machine a have 4of them

Thank You,

Mikey