Inconsistent print quality

[RRS614]

I have a tr8520 that randomly prints blurred lines on the bottom half of the page. The lines that are blurred are never the same ones, and never all of the lines. Sometimes there are 1 to 2 blurred lines and other times there are 6-8 blurred lines. I perform all of the maintenance items, then it will print fine for about 15-20 pages then the problem returns. Bought printer in June 2018. 

[Patrick]

Hi RRS614,

Because performing multiple printhead cleanings did not get your PIXMA TR8520 to print correctly, your PIXMA TR8520 would require service.  You are eligible for Canon's Upgrade Program. This is for out of warranty units which have been diagnosed to require service, or for some reason are incompatible with a new or upgraded system. This option allows you a one-time opportunity to purchase a replacement product, discounted from the list price.

If you would like to take part in this option, please call our Sales Department at (866) 443-8002 Monday through Saturday, 9am to 9pm. Let them know you have been working with technical support and the Canon Upgrade Program was offered.