Patent ID: 8643688

Claim:
A printing device for printing an image on a transfer paper and outputting said transfer paper along a first direction, said printing device comprising: a casing for accommodating said transfer paper, wherein said transfer paper comprises a releasing paper part and plural medium parts, wherein every two adjacent medium parts are separated from each other by a gap; an upper cover connected with said casing, wherein said upper cover is rotatable relative said casing, so that said casing is selectively covered or uncovered by said upper cover; plural light sources disposed on said upper cover and arranged in a row for emitting plural light beams, wherein said plural light sources are arranged along a second direction, which is perpendicular to said first direction, wherein said plural light sources are arranged from an edge of an inner surface of said upper cover to a position beyond a middle point of said inner surface; and a sensing module disposed under said plural light sources and movable relative to said casing along said second direction, wherein after said light beams transmitted through said gap are received by said sensing module, said gap is detected by said sensing module.