Epson seems to have discontinued support for the TM-T88ii receipt printer. The only available drivers for this printer by Epson is for 32-bit operating systems up to Windows XP. The POS58 Driver for another branded printer has been found to work both with Windows 7 x64 and the Epson TM-T88ii printer.
The printer driver might be found at the following location.
We recently upgraded our client that was using the TM-T88ii printer with a new Epson TM-T20ii USB printer and found it well worth the upgrade and would recommend this to anyone with an older TM-T88ii printer.
We hope that this information is helpful. Please let us know how this has helped you or if you have additional questions. As always Firestone Technical Resources, Inc. is here to help with your computer support issues - "Providing personal service for your impersonal technology."