Image forming apparatus with thermal printing head and printing method thereof

Abstract

An image forming apparatus using a thermal printing head (TPH) and a printing method thereof to print a borderless image on both sides of a printing medium. The image forming apparatus includes first and second feeding units respectively disposed at front and rear sides of the TPH to transfer the printing medium at a predetermined printing speed and a pair of out-feed rollers that co-rotates and feeds out the printing medium, in which one of the out-feed rollers rotates in contact with the pick-up roller. A platen roller co-rotates in contact with the printing medium fed by the first and second feeding units The TPH has a printing position in which the TPH is pressed towards the platen roller to form a printing nip, and an open position in which the TPH is separated from the platen roller. The knock-up plate has a pick-up position where the printing medium comes in contact with the pick-up roller and a stand-by position where the printing medium loaded thereon is separated from the pick-up roller. The knock-up plate is respectively disposed to the pick-up position and the stand-by position when the TPH is disposed to the printing position and the open position.