Black streaks in Hp 5510

I think the scanner part is defective, possibly the carriage. Try leaving the lid up while scanning a small item and see if you can observe any problem.
 
So it's a problem with both manual feed and automatic.

What happens when you print a scan -- and what happens when you print something from the computer (like a Word document or something else that has NOT been scanned).


 
It's pretty obvious that the fault is with the scanner -- presumably these black lines appear when you preview the scan as well as when you print.

The problem with all-in-ones is they are being sold so cheap (I suspect as a ploy to sell inkjet refills at a far greater profit % than on the machine) that the construction quality suffers and repair is often not cost effective because they are so complex.

Try updating the driver package for your model and if that doesn't work contact the retailer -- even if out of warranty, normal consumer rights suggest that you should expect a reasonable lifespan on consumer durables such as computer equipment.