A cradle unit for an inkjet printer including: a body complementary to a removable inkjet cartridge of a type having a pagewidth printhead, an ink supply and a capper assembly; and a controller for controlling the operation of the printhead to facilitate printing when the removable inkjet cartridge is received within the body; and an electromagnet assembly on said body which is controlled by said controller for operating said capper assembly of the removable inkjet cartridge.