font changing

hi,

i have a created my own pageformat(ZA3) for printing invoice on a dot matrix printer.for this page format an output device (ZB3)was created by basis consultant.when im seeing print preview with this output device(ZB3) assigned in VF03 tcode,the font is different from which i gave in smartform.when i give different output device(for ex: LP01) ,the print preview is showing the correct font which i gave in smartform.please suggest solution.

Thanks and Regards

k srinivas