... would be my guess here. Very few references found but so is the situation for the German term.

One example:

http://www.edison.edu/library/techfaqs/
"5. Now call up your print job on the <B>central print computer</B> by entering the “User ID” you created above."

Note that such a computer may also be termed "central printing workstation", as found at http://trudata.org/local_sites/copicard.biz/Products/vendwin...
"This computer becomes the <B>central printing workstation</B> where print queues are monitored and managed."

In addition, a "Zentralrechner" may also be a "host computer", which goes to show that the provided context is not exactly sufficient...