TR 8520 not printing every 4th line

[kunz]

I have a TR 8520 and it is not printing every 4th line.  I have done all of the alignments and cleaning and deep cleaning... everything possible, and it continues to do this.  I have also changed each of the ink cartridges (true Canon ink cartridges).  However, on high quality printing, it does not do this.  Based on this, I don't think it's the printer, but perhaps something else.  The printer still works really well, other than this one detail.  Other than the alignments, cleaning, and other accessories to try to fix it through software, is there something else I can do?  The vertical lines shown here are what I am referring to....

Thank you

[Patrick]

Hi kunz,

Because performing cleanings and alignments did not get your PIXMA TR8520 to print correctly, your PIXMA TR8520 would require service.  If your PIXMA TR8520 was purchased less than a year ago, please contact one of Canon's Technical Support Representatives via phone or chat to obtain your in warranty options. To contact a Technical Support Representative, please use the link below:

https://mycanon.usa.canon.com

If your PIXMA TR8520 is out of warranty, 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.