Abstract: A paper feeding device is capable of judging that a paper jam occurs on the basis of output from a first paper detecting switch and a second paper detecting switch. These paper detecting switches are respectively provided ahead of and behind a registration roller which feeds paper sheets to an image forming section. If the first paper detecting switch is turned on when a predetermined time has elapsed since the registration roller started to feed a paper sheet to the image forming section, it is judged that a duplicate paper feeding state has occurred where a plurality of paper sheets are simultaneously fed. If the second paper detecting switch is turned off in the case where it is judged that a duplicate paper feeding state has occurred, it is judged that a paper jam has not occurred. The registration roller is stopped so it will later be ready to feed the subsequent paper sheet.

Abstract: In a time period from the time point where the forward end of a paper sheet fed from a pair of paper separation rollers reaches a registration roller to the time point, where the registration roller is driven, when the load torque exerted on a forward roller is not less than second regulated torque, the transmission of power to the forward roller is released by a torque limiter provided for the forward roller. In this case, therefore, the force of paper feeding produced by the pair of paper separation rollers is regulated. Consequently, a suitable force of paper feeding can be applied to the paper sheet, thereby to make it possible to regulate the paper sheet straight in the direction of paper feeding as well as to prevent the paper sheet from continuing to be fed even if the amount of deflection of the paper sheet is saturated between the pair of paper separation rollers and the registration roller to prevent the paper sheet from being wrinkled.

Abstract: In a time period from the time point where the forward end of a paper sheet fed from a pair of paper separation rollers reaches a registration roller to the time point where the registration roller is driven, when the load torque exerted on a forward roller is not less than second regulated torque, the transmission of power to the forward roller is released by a torque limiter provided for the forward roller. In this case, therefore, the force of paper feeding produced by the pair of paper separation rollers is regulated. Consequently, a suitable force of paper feeding can be applied to the paper sheet, thereby to make it possible to regulate the paper sheet straight in the direction of paper feeding as well as to prevent the paper sheet from continuing to be fed even if the amount of deflection of the paper sheet is saturated between the pair of paper separation rollers and the registration roller to prevent the paper sheet from being wrinkled.