Xerox DocuPrint 4850 NPS System Overview Manual page 28

PRINTERS
CCU changeout cart
3-6
The cart is used to remove and install the customer changeable unit
(CCU), which consists of the color developer housing and the dry ink
bottle. Because of the physical weight of the CCU, the cart is required
to make the change.
The carts also serve as storage devices for the CCUs that are not
currently in use in your system. For example, if you use both the red
and blue dry inks in your operation, one CCU is always out of the
machine in storage on the cart while the other CCU is installed.
Note: You should have a cart for each CCU, where one cart is
always empty and available to remove the CCU that is installed in the
system. However, if your printer will only be used to print one color
(that is, the CCU will never be removed), or if there is more than one
DocuPrint 4850 or 4890 in operation at your site, it may not be
necessary to have one cart per CCU. Consult your site
representative for more details.
XEROX DOCUPRINT 4850/4890 NPS SYSTEM OVERVIEW GUIDE