Mine started doing that about 6 months ago. Banding about 1/4 inch
wide across the paper where the yellow ink wasn't printing. Tried like
half a dozen deep cleaning cycles, didn't change a thing. Then tried
the take out the print head and soak in Windex trick, no help there
either. Talked to Canon helpline, best guess was print head died.
Given the cost of a replacement printhead, bought a new printer
instead.
Jerry
		
		
	 
My first i850 was still under warrenty when it initially started
banding. Rather than mess around with it they sent me a refurbished
one. They (can't recall who "they" is) had sent along packing material
for me to return the original one that was still under warranty. So,
this is the second one that is doing the same thing...........now that
the warranty is kaput I will probably keep it for an auxillary printer
for letters only. I feel that it has served me well. The price was
certainly right. However, I have thoughts about going to dye
sublimation as my next printer. I did use one many years ago at a
college I was attending - they we prohibitive then price wise.
However, they have come down quite a bit and  are great
printers............but that's another story.
Thanks for your time.
MAgron