Management system and management method

A management system, comprising:

• a management server connected to a network;
• one or more image forming apparatuses connected to the network, each of the one or more image forming apparatuses being managed by the management server;
• and
• one or more terminals that access the management server, each of the one or more terminals being connected to the network, wherein
• the management server includes
• a first memory that stores a contract value database, a contract value for each of the one or more image forming apparatuses being stored in the contract value database, the contract value being set in licensing contract regarding each of the one or more image forming apparatuses, the contract value being a remaining amount of toner when performing toner replacement,
• a second memory that stores a first information processing program,
• a first processor that executes the first information processing program, and
• a first communication device capable of communicating with the one or more image forming apparatuses and the one or more terminals,
• each of the one or more image forming apparatuses includes
• a third memory that stores a second information processing program,
• a second processor that executes the second information processing program, and
• a second communication device capable of communicating with the management server,
• when the second processor of each of the one or more image forming apparatuses executes the second information processing program, the second processor
• notifies the management server of information on the remaining amount of toner of the corresponding image forming apparatus via the second communication device, and
• when the first processor of the management server executes the first information processing program, the first processor
• acquires the information on the remaining amount of toner from each of the one or more image forming apparatuses via the first communication device,
• makes a toner remaining amount history by combining the information on the remaining amount of toner with time and date information, the toner remaining amount history being stored in the first memory as a toner remaining amount history database,
• detects, based on the toner remaining amount history, that the toner replacement has been performed when an increase rate of the remaining amount of toner exceeds a threshold value, and
• determines, based on the contract value in the contract value database, whether the remaining amount of toner before the toner replacement is not more than the contract value when the toner replacement is detected, and notifies the one or more terminals of that the performed toner replacement corresponds to a contract violation when the remaining amount of toner before the toner replacement is more than the contract value.