How to Print Unix Files on a Xerox 9700 Page Printer

[Hampton at his-phoenix-multics.arpa]

My situation is this:

I have a Honeywell Bull X-20 Unix system running System V.3, with a 9
track magnetic tape unit attached.  I receive print files from an IBM
mainframe via SNA RJE.

Heerere is my problem:

I have to find a way to write these print files to the tape in such a
mwanyner that they can be printed by the Xerox 9700 page printing system. 
Has anyone already solved (or been defeated by) this problem?

The Xerox 9700 can recognize tapes in a variety of formats, including
several IBM formats (DOS/360 and DOS/VS/370 POWER and POWER VSE, DOS/360
and OS/360 standard tape formats, among others).  I know how to write
tapes using "tar" and "cpio", but of those formats, the 9700 dooesn't
know.

I suppose this problem could be solved from either of two directions.  I
could program the 9700 to accept "tar" or "cpio", or I could get the
X-20 to write the print files in a format already familiar to the
printer.  I don't know the JDL (language) used to program the 9700 and
would rather not have to learn it to solve this problem.

Can anyone help with this problem?