Image forming apparatus connected to a sheet processing apparatus which applies sheet processing such as stapling to a sheet formed image by the image forming apparatus. The image forming apparatus includes an input terminal for inputting image forming job, an image forming unit for forming an image on a sheet in accordance with the image forming job inputted by the input terminal, a discriminator for discriminating if a first image forming job does not include sheet processing whereas a second and subsequent image forming job includes sheet processing, and a controller for instructing the sheet processing apparatus to perform a preparatory operation for he second image forming job during the first image forming job in accordance with a discrimination result, such as by moving a staple unit to designated position for the second image forming job.