Patent ID: 8040535

Claim:
An image forming method for controlling a first image forming apparatus to print one of a color page including a color image and a black-and-white page without including a color image, both of which are mixed in a print job, and controlling a second image forming apparatus to print the other one of the color page and the black-and white page, the image forming method comprising: a stacking step of stacking a sheet having the one printed by the first image forming apparatus to a first discharge tray of the first image forming apparatus; a storage step of storing identification information in a memory, the identification information identifying an abnormal sheet among the sheet stacked in the first discharge tray in said stacking step; a feeding controlling step of, after the sheet stacked in the first discharge tray is set to the second image forming apparatus as an insert sheet, controlling to feed the insert sheet so that a sheet having the other one printed by the second image forming apparatus and the insert sheet are discharged to a second discharge tray of the second image forming apparatus in a predetermined page order; a reading step of causing the second image forming apparatus to read the identification information stored in the memory; and a discharge control step of controlling, when the insert sheet is determined to be the abnormal sheet based on the identification information, the insert sheet to be discharged to a third discharge tray different from the second discharge tray.