Ok, I assume you just found one of these sitting in a dusty corner somewhere, because no one in their right minds would dump all that data over a parallel port.
First off, there is a whole website devoted to the topic of Parallel Port Scanners under Linux. You should check that out.
At least one user has reported that he got a parallel-port version of the Microtek Color PageWiz working under Linux by using the new ppSCSI drivers. Apparently, the PageWiz has an OnSpec parport->scsi chip inside, and works with the onscsi module.
The microtek backend knows nothing about the parallel port; it works in the SCSI realm alone. However, if the scanner has SCSI guts, with a parallel-port convertor, and if a Linux driver exists which can translate SCSI and talk to that chip over the parallel-port, it could work. (Again, I ask, why go through all that trouble?)
My guess is that if you have a parallel port Microtek scanner, and if there exists a SCSI version of the same model known to work with the microtek backend, then one of the ppSCSI drivers might do the trick.
I know of no such drivers for any platform aside from Linux.
If you have any useful info to add, send it to me, and I'll put it up on this page.
If you have any questions, don't ask me, because all that I know is already on this page.