to t 25 that is it is understood that the light emission is carried out by the ratio of 3 7 15 such that the interval from the first light emission to the second light emission is two three for the third light emission and fifteen for the fourth light emission in addition in the present embodiment as shown in fig5 the input image data sixteen bits is transmitted along with the number information of the scanning line four bits to the electro optic apparatus 11 through a 20 bit data bus furthermore the flow of the acquisition process of the image data in the image processing device 10 will be described with referring to fig7 fig7 is a flow chart showing the acquisition process of image data in the image processing device 10 as shown in fig7 at step s 500 whether the image data has been obtained or not from the external device such as a pc is judged if judged as the image data having been obtained yes the flow proceeds to step s 502 and if not no waits till the image data has been obtained in the case of having proceeded to step s 502 whether f 1 which is the flag.