Sheet feeding apparatus, image forming apparatus and sheet feeding method

A sheet feeding apparatus comprising:

• a controller;
• a multiple-feed detecting section that detects recording sheets superposed with each other to be transported by a plurality of rolls in a direction;
• a separating section that, in a case where recording sheets superposed with each other are transported, separates an uppermost sheet of the recording sheets from an other sheet;
• a slippage detecting section that detects a slippage of the uppermost recording sheet with respect to a roll;
• a transporting-speed reduction suppressing section that suppresses a transporting-speed of the uppermost recording sheet from reducing from a value,
• the separation section including:
• a transporting roll that transports recording sheets in a transporting direction;
• and a separation roll that is placed to be opposed to and to be press-contacted with the transporting roll through a recording sheet,
• a drawing roll disposed downstream from a press-contact portion between the transporting roll and the separation roll, the drawing roll drawing a recording sheet out of the press-contact portion and transporting the drawn recording sheet in the transporting direction;
• an arrival detecting section that detects whether the uppermost recording sheet arrives at the drawing roll;
• and
• a load torque detecting section that detects a load torque of the transporting roll;
• the transporting-speed reduction suppressing section changing a separation torque of the separation roll based on a result of detection by the arrival detecting section, a result of detection by the multiple-feed detecting section and a result of detection by the slippage detecting section, the transporting-speed reduction suppressing section being controlled by the controller,
• wherein in a case where a slippage is detected by the slippage detecting section before the arrival detecting section detects that the uppermost recording sheet arrives at the drawing roll and where the load torque of the transporting roll is equal to or more than a torque value, the transporting-speed reduction suppressing section increases the separation torque, and
• in a case where a slippage is detected by the slippage detecting section before the arrival detecting section detects that the uppermost recording sheet arrives at the drawing roll and where the load torque of the transporting roll is less than the torque value, the transporting-speed reduction suppressing section decreases the separation torque.