Epson escp data

Helo,
I am capturing data om COM1 from an device.
This device is a medical device which can only print data to a thermal printer.
I need to have this data on a file.
So I capture with java (with sun comm library) the data on serial Com1.
So I have all my data.
Problem is the following.
It is epson escp data. So many of the data is not readable, only the ASII
characters.
I would like to plot all this data on a file or image.
If i look the captured data on hexadecimal I can recognise the epson escape
codes, but I don't know how to format this raw data to a readable
file(postscript, BMP image, EPS...)
I am quite knew with this.

Any help for this problem will be appreciate,
Many Thanks,
Romain