A cradle unit is provided which has a body complementary to a removable printhead cartridge, the removable printhead cartridge having a pagewidth printhead and a capper assembly, a controller for controlling operation of the printhead to facilitate printing when the removable printhead cartridge is received within the body, and an electromagnet assembly on the body which is controlled by the controller for operating the capper assembly of the removable printhead cartridge to permit the operation of the printhead.