It looks like there are several type sold for that printer depending on the mounting type required...
eg. RHI90N-0LAAAR61N-00100
From the P&F datasheet,
That part number breaks down to:
RHI90N Series,
38mm hollow shaft,
Plug 9416, 12 pin
Radial cable exit
10-36V push-pull output
100 line count ??????
or,
RVI58N-YY2YYR16N-02500, which has a 6mm shaft, 5V supply and 5V RS422 outputs..
It does appear that any general incremental encoder should work & it appears it only uses the two quadrature channels.
I'd try something like this, as an experiment:
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Try it on the 5V supply first.
It would...