A technique is proposed to provide an appropriate notification in accordance with the state of occurrence of conveyance errors. The level of maintenance required to normalize a conveying function is determined depending on the number of errors, and a notification is provided by displaying a message to a user or by transmitting a message to a service center depending on the level of maintenance. Since the message to the user indicates a specific content of maintenance to normalize the conveying function, the user can normalize the conveying function by taking appropriate measures. On the other hand, since the message to the service center indicates the required level of maintenance, a service person of the service center can normalize the conveying function by going to a place where a multi-function machine, for example, is installed and repairing the multi-function machine.
