Lynda, this may be quite simple or very much not so.
Firstly what do you mean by “f key”? Cmnd-Shift-number or top row of extended keyboard?
Secondly what OS and which AS version?
Thirdly - it might prove useful to know - do you have QK? And finally - does it have to be done by an “f key” or is the concern simply to choose a particular printer by any (AS) means?