Disposable steam generator for domestic steam appliances, comprising a base that is applicable permanently to the steam appliance, a hollow body that forms the steam chamber and is connected to the base so as to be removable and replaceable, and at least one electric heating element. The controller is configured to queue an exposure job corresponding to the exposure process and an update job corresponding to the update process; and cause the exposure device to perform an exposure process corresponding to the queued exposure job if the queued exposure job is output, and perform an update process corresponding to the queued update job if the queued update job is output. Here, the electrode wiring of the second layer and the electrode wiring of the third layer are so arranged as will not be overlapped on the edge portions on both sides of the electrode wiring of the first layer. The carrier further includes means for urging a data storage device in the passage in pressing engagement against the circuit board.