An image forming apparatus includes: an image forming unit; a sheet feeding unit; an upper frame; a sheet feeding frame; and a lower frame. The faxmodem device may be comprised of hardware or software in any proportion. A numerical constant functionally equivalent to the numerically computed error detection code is determinable from the initialized data in the timestamp subfield and the corrector subfield. Therefore, methods for preparing these polymers or polymer compositions and medical devices are also encompassed by this disclosure.