IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD

To accurately correct magnification and a position of an image formed on a back surface of a sheet.SOLUTION: An image forming apparatus comprises: a transfer unit that transfers an image formed by an image forming unit to a sheet; a fixing unit that heats the sheet conveyed from the transfer unit to fix the image transferred to the sheet; and a paper re-feeding path that conveys the sheet passing through the fixing unit to the transfer unit again. The image forming apparatus further comprises: detection units that are arranged downstream of the fixing unit in a sheet conveyance direction and detect an environment inside the apparatus or the characteristics of the sheet; and a correction value calculation unit that calculates, from the values detected by the detection units, a predicted expansion/contraction rate of the sheet when an image is transferred by the transfer unit to a back surface of the sheet.SELECTED DRAWING: Figure 2 【課題】用紙の裏面に形成される画像の倍率及び位置を精度良く補正する。【解決手段】画像形成部で形成された画像を用紙に転写する転写部と、転写部から搬送されてきた用紙を加熱することで、用紙に転写された画像を定着させる定着部と、定着部を通過した用紙を、再度転写部に搬送する再給紙路とを備える。また、用紙搬送方向における定着部の下流側に配置され、機内環境又は用紙の特性を検知する検知部と、検知部で検知された値から、転写部における裏面画像転写時の用紙の予想伸縮率を算出する補正値算出部とを備える。【選択図】図２