Same thing for MG5500
I have the same problem - my letters are doubling.
I did the manual heads alignments, not helping.
http://ugp01.c-ij.com/ij/webmanual/PrinterDriver/W/MG5500%20series/1.0/EN/PPG/dg-c_alignment.html
Scans of printed pages are here:
https://drive.google.com/open?id=1Vm8PJhXEzdBERJ57OvQDq6WeBnLOR-Nf
https://drive.google.com/open?id=1cA7aOmr5gJv-yz0dknssQuVOL64loqjM
I did the automatic heads alignment by this:
http://ugp01.c-ij.com/ij/webmanual/Manual/S/MG5500%20series/EN/BG/bg-maintenance1600.html
I did try cleanup the strip by this manual:
https://support.usa.canon.com/kb/index?page=content&id=ART109134
Not better.
My most concern is that all the numbers a double-printed.. on both pages. And the black E column on the pattern_01 is definitely not rectangular...
And one more thing - letters above the columns looks good!! No doubling! Only numbers, + and - signs and arrows are doubling...
Any suggestions?