How will I fix my Teardown printer?

Pisen, it's not clear what you mean when you talk about your "Teardown" printer. Are you saying you've disassembled your Canon 9950F printer and can't figure out how to put it back together?

There is a service manual available for your printer; unfortunately it's a bit light on actual assembly/disassembly instructions, but it does have a parts diagram showing the relative position of all the parts, so that might be worth a look.

Canon CanoScan 9950F Service Manual (Page 24 of 30) - ManualsLib

If that's not what you meant, or your printer is different that what your question is categorized under, please let us know and we'll see what we can do to help.