1. A multi-function scanner for selectively scanning a first document without a laser/anti-counterfeit mark and a second document with the laser/anti-counterfeit mark, the multi-function scanner comprising: a scan module comprising: a first light source enabled to emit visible light rays to illuminate the first document; a second light source enabled to emit infrared light rays to illuminate the second document; an image sensor; and a lens module for focusing reflected light rays from the first or second document onto the image sensor; and a scan mode control unit for controlling the scan module to selectively enable the first light source and the second light source to perform a first mode scan or a second mode scan.