A flexible ink bag in which ink consumed by a printer is stored is detachably
mounted
in the printer. A non-contact type memory IC is provided on the ink bag. A data
communicator opposes to the memory IC to perform non-contact data communication.
The memory IC stores data indicating an amount of ink remained therein. The ink
bag is mounted such that the memory IC is substantially immovable with respect
to the printer, regardless of the consumption of ink.