Knife-type folding machine

A knife-type folding machine comprising:

• a conveying unit conveying a sheet along a conveying path;
• a stopper extending across the conveying path at a right angle, the sheet being positioned at a predetermined folding position on the conveying path by corning into contact with the stopper at a leading end thereof;
• a knife-type folding unit folding the sheet positioned at the folding position in a conveying direction;
• and
• an anti-bounce roller unit arranged at an upstream end of the folding position to prevent bounce of the sheet from the stopper, wherein
• the conveying unit includes
• a pair of drive and idle rollers which are arranged at upstream and downstream ends of the conveying path,
• a plurality of conveyor belts extended between the pair of drive and idle rollers, conveying surfaces of the plurality of conveyor belts forming the conveying path, and
• a roller drive mechanism rotating the drive roller, wherein
• the anti-bounce roller unit includes
• a roller support arranged above the folding position,
• at least one slide guide extending in the conveying direction above the conveying path, the roller support being slidably attached to the at least one slide guide,
• a support drive mechanism sliding the roller support back and forth, and
• at least one roller attached to the roller support so as to rotate around a horizontal axis extending at a right angle to the conveying direction while being pressed against the plurality of conveyor belts of the conveying unit,
• the sheet entering the folding position while passing through the at least one roller and the plurality of conveyor belts, an outer surface of the at least one roller contacting with a tail end of the sheet when the sheet abuts on the stopper, characterized in that
• the knife-type folding machine can switch operation between a normal operation mode and a setting mode, and, in the setting mode, the plurality of conveyor belts of the conveying unit are continuously rotated at a constant speed so that the sheet is conveyed to the folding position and positioned at the folding position while the knife-type folding unit is kept on a standby state, wherein
• the knife-type folding machine further comprises
• a sensor detecting a rotational speed of the at least one roller of the anti-bounce roller unit,
• a roller rotational speed monitoring unit receiving a detection signal from the sensor and sending an appropriate position arrival signal in the setting mode when the rotational speed of the at least one roller starts to change, and
• a roller position setting unit operatively connected to the support drive mechanism of the anti-bounce roller unit and activating the support drive mechanism in the setting mode so as to move the at least one roller from an upstream or a downstream of a tail end of the sheet positioned at the folding position toward the tail end at a constant speed and stopping the support drive mechanism when the roller position setting unit receives the appropriate position arrival signal.