Patent ID: 8456424

Claim:
An input display device, comprising: first operation key that is selected to execute a predetermined processing; an operation panel including: a first display operation area that, based on selecting the first operation key, displays a first operation screen, wherein the first operation screen enables operation screens to be switched hierarchically and displays a fixed-arrangement of operation keys in respective layers; and a second display operation area that displays an operation history, wherein the operation history includes a second operation key indicating that the first operation key has been selected; a selected key use determination unit configured to determine when the first operation key is selected from the first display operation area and the second operation key is selected from the second display operation area; a storage processing unit configured to successively store results determined by the selected key use determination unit into a storage device as operation history information; a selected key use history display control unit configured to display the operation history information stored in the storage device into the second display operation area; and a display switching control unit configured to, based on selecting the second operation key from the second display operation area, restore the first operation screen in the first display operation area, wherein other operation keys in the second display area are grayed out upon selecting a third operation key.