DISPLAY DEVICE, IMAGE FORMING DEVICE, METHOD OF DISPLAYING KEYPAD SCREEN, AND PROGRAM FOR DISPLAYING KEYPAD SCREEN

A display device includes: a display unit capable of displaying a setting screen having an input area for an input value and a keypad screen having soft keys on the same screen; a determiner configured to determine an acceptable input value range of the input area displayed on the display unit; and a display controller configured to display only soft keys on the keypad screen, wherein the keypad screen has a fixed area in which the soft key is fixedly displayed and a variable area in which the soft key is variably displayed, the soft keys are classified into a common key and an individual key other than the common key, and the display controller displays the common key in the fixed area of the keypad screen and the individual key in the variable area of the keypad screen out of the soft keys.