paper size of 6"x2.75" keeps shifting during print

[Toulouse]

my goal is to print onto blank checks whose size is 6"x2.75". dont have control over its size, nor does the bank allow for check printing in their entirety by the customer, so this is the only alternative. my only other requirement is that a printer must be on the small size and lightweight. i have figured everything out, so my only problem is that such small checks shift as they make their way through the few printers i have tried. i have tried canon mg2522, canon ip110, and brother l2320d. also l2320d is about as big and heavy as i am willing to go. could anyone please suggest what i can do to assure smooth and shiftless printing? or perhaps there are other brands/models that are much better at handling such small sizes? i was thinking of trying the following ones: canon lbp6230, canon lbp6030, hp laserjet pro m102, xerox 3260. any help would be greatly appreciated! thank you!