Patent ID: 7949293

Claim:
An image forming system, comprising: an image forming device that forms an image on a sheet, the image forming device including: an operation unit for selection of the sheet and a cover to be used for bookbinding; a start button operable by a user for starting an image forming provided in the operation unit; and a control unit for control of warning; and a bookbinding device that stacks a plurality of the sheets, forms a bundle of the sheets, and binds a book by wrapping the bundle of the sheets with the cover in a square-shape, the bookbinding device including: a measuring unit for measurement of a thickness of the bundle of the sheets, wherein the image forming system is configured to operate in, a first warning mode that is executed before a depression of the start button and in a second warning mode that is executed after the start button is operated, wherein the control unit: calculates a difference between a length of the selected cover, and a sum of twice a length of the selected sheet and a spine width, and determines a warning, based on a result of comparison between the difference and a predetermined value, and executes the determination of the warning in the first warning mode that determines issuing of a warning, based on the result for which the difference is calculated with a spine width of a set value, and in the second warning mode that determines issuing of a warning, based on the result for which the difference is calculated with a spine width of the measured thickness of the bundle of sheets.