IMAGE FORMING DEVICE

摘要

PURPOSE:To suppress the easy forgery of paper moneys or the like by applying additional information to regenerative images without lowering the picture quality of regenerative images even when it is ambiguously judged whether copy is inhibited or not. CONSTITUTION:A modulation circuit 53 inside generates the two kinds of triangular waves and outputs two pulse duration modulated signals 54 and 55 modulated based on the respective triangular waves by comparing these triangular waves with an image signal 52. When a judge signal 41 is at a low level (the paper money is not judged), a selector 56 selects the pulse duration modulated signal 54 and reproduces the normal image and when the judge signal 41 is at a high level (the paper money is judged), the selector locally selects the pulse duration modulated signal 55 corresponding to an output signal 59 of an additional information generation circuit 58 and applies the additional information to the normal regenerative image.