Patent ID: 8879942

Claim:
An image forming apparatus, comprising: a sub controller configured to transmit a notification of an event of a status change; and a main controller configured to receive the notification; wherein the main controller comprises: a queue configured to store a status that includes a status ID and a status value in the notification on the basis of the notification; a first status storage unit; a second status storage unit; and a status renewing-and-notifying unit configured to: (a) obtain statuses from the queue in turn, temporarily memorize the statuses, and store the status values at addresses corresponding to the status IDs in the first status storage unit; (b1) notify a component corresponding to an objective status among the temporarily memorized statuses of the objective status and a dependent status dependent on the objective status either at a same time or in a reversed time order if the temporarily memorized statuses includes the objective status and the dependent status, and the status value of the dependent status in the first status storage unit and the status value of the dependent status in the second status storage unit are different from each other; (b2) notify the component of the objective status if the temporarily memorized statuses does not include any dependent statuses dependent on the objective status or if the temporarily memorized statuses includes a dependent status but the status value of the dependent status in the first status storage unit and the status value of the dependent status in the second status storage unit are identical to each other; and (c) store the status value of the status that the component is notified of at an address corresponding to the status ID of the status in the second status storage unit at a notification timing of the status.