IMAGE FORMING DEVICE AND PAPER LENGTH MEASURING METHOD

PROBLEM TO BE SOLVED: To provide an image forming device and a paper length measuring method capable of measuring paper length as early as possible. SOLUTION: The image forming device includes: a paper feeding means having a paper placement plate which is arranged within a paper feeding cassette and in which an inclination angle in a paper feeding direction is changed in accordance with placement amount of paper, and sequentially feeding paper sheets stacked on the paper placement plate from the uppermost paper sheet; and an image forming means transferring a toner image formed by an image forming part to paper fed by the paper feeding means for image formation. An acceleration detection sensor detecting change in the inclination angle in the paper feeding direction is provided in the paper placement plate. By using the acceleration detection sensor and a paper presence/absence detection sensor provided downstream of a paper carrying path, time from detection of passage of a tip of paper by the paper presence/absence detection sensor after start of paper feeding until vibration of the paper placement plate generated when a rear end of the paper is made to pass through a paper feeding roller is detected by the acceleration detection sensor to determine the rear end is measured, so as to measure the paper length. COPYRIGHT: (C)2011,JPO&INPIT