Black ink streak on left side of paper on hp 1012, just put in new toner

Defective cartridge.

You have a defective cartridge.

It is either the toner cartridge or the fuser.
Put paper in the manual feed tray.
Print the Configuration Pages.
When the sheet is half way fed into the printer, open the top cover.
Remove the toner and look at the sheet of paper. If you see the black streak, the toner is bad.
If the sheet looks good, the fuser is bad. Probably a bad roller, which you can see looking at the fuser.

I was going to suggest removing the fuser and looking at the rollers, but on this printer it's a major operation.
Instead let's run the half test. Put paper in the manual feed tray(tray 1). Print to the printer. When the sheet of paper gets pulled about 3/4 of the way in, open the top cover. Pull out the toner cartridge. Look down at the paper. Does it have a streak down the right side? If yes, replace the toner, if no, have the fuser replaced.

black streaks the toner cartridge is leaking from the left side which is easy to check pull the tone and look at the gears on the left side to see if toner is present. if these gears have toner on them the cartridge is leaking replace it. check the fuser for wear marks on the hot roller which is the top roller when these get worn through the outer coating they will create black streaks

Checking the paper path for ink deposits might be the solution. I had a similar problem sometime ago, where the fuser got some scratch damage for unknown reasons and i suppose was causing unfused ink to accumulate after the fuser, leaving streaks on paper.

look at the toner cartridge it is be coming from there,replace. check to see if there is something stuck on hte drum causing the blotches, clean w/alcohol or replace

Check your Toner Carts.
Is the line a certain color?
Black perhaps?

Lift the door of the toner cart.
If you see a streak on your toner drum, you will see a streak on your paperwork.

Look at your fuser as well.
Is there a problem with the big orange roller?
BEWARE! Don't touch the fuser roller its EXTREMELY HOT!
Let the printer cool down before inspecting.

You should try changing the toner cartridges first. There may be something stuck in it causing the noise and streaking

This can be one of two

Print cartridge (you can do it, replace toner cartridge)

or Fuser (needs to go to doctors)

stop a print half way threw to confirm that it is print cartridge, good chance it is.

Links to my previous post on this problem below

HERE and HERE