IBM 3852-2 Hardware Reference Manual page 48

The blue lever on the top left side of the printe r
locks the carria ge. Locking the carria ge protec ts
the ink-je t system from mechanical shock and
vibrat ion that may occur during transp ortatio n
of your printe r. It also autom aticall y executes
the capping of the ink nozzles. The carria ge
canno t be properly locked if power is Off. The
following steps allow you to lock the carriage:
1. Turn the power On.