Display device, image forming device, method of displaying keypad screen, and program for displaying keypad screen

A method of displaying a keypad screen in a display device, comprising the steps of:

• displaying, on a screen of a display unit, a setting screen having an input area of an input value and a keypad screen having soft keys for entering the input value in the input area;
• determining an acceptable input value range of the input area displayed on the display unit;
• and
• controlling display such that only soft keys for entering an input value within the acceptable range determined in the determining step are displayed 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 commonly used in each input area and an individual key other than the common key, and
• in the display control step, out of the soft keys for entering the input value within the acceptable range determined in the determining step, the common key is displayed in the fixed area of the keypad screen, and the individual key is displayed in the variable area of the keypad screen.