1. A control apparatus for controlling an imaging device, including (a) a printing section for performing printing on a sheet, (b) a document reading section for reading a sheet, (c) a display section for displaying information, and (d) an operation section for accepting a user's operation, and allowing a user to use (i) a first input mode in which setting information serving as information to be acquired from a user is acquired by the display section displaying a setting window for setting the setting information and by the operation section accepting, from the user, an operation of designating the setting information and (ii) a second input mode in which the setting information is acquired by the printing section printing an entry sheet and the document reading section reading the entry sheet on which the user has written the setting information, the control apparatus comprising: a selecting means for selecting either the first input mode or the second input mode when the imaging device acquires the setting information from the user; and an instructing means for instructing the imaging device to acquire the setting information in the first or second input mode selected by the selecting means, wherein the selecting means receives display performance information indicative of resolution or size of the display section of the imaging device from the imaging device, and chooses an input mode in accordance with the display performance information thus received.