that the image forming apparatus holding the image data is connected to lan 56 yes at step 406 shown in fig1 and that the image data exists in the image forming apparatus yes at step 408 shown in fig1 here it is assumed that image forming apparatus 52 d holds the image data of interest image forming apparatus 52 b transmits an image data request requesting transmission of the image data to image forming apparatus 52 d and waits until the image data is received from image forming apparatus 52 d step 410 shown in fig1 receiving the request image forming apparatus 52 d transmits the image data to image forming apparatus 52 b receiving the image data from image forming apparatus 52 d image forming apparatus 52 b transmits the image data to image forming apparatus 52 c step 412 shown in fig1 receiving the image data from image forming apparatus 52 b image forming apparatus 52 c executes a process for printing the image data step 326 shown in fig1 in the following an operation following step 404 will be described assuming that the image forming apparatus holding the image data is not connected to lan 56 no at step 406 shown in fig1 or that.