Book block conveying device

A book block conveying device transporting book blocks one by one in a lying position to a bookbinding apparatus so as to supply the book block to the bookbinding apparatus in synchronization with a motion of the bookbinding apparatus to take in the book block, comprising:

• a first conveyor having an entrance, an exit, and a transport surface extended from the entrance and the exit, the first conveyor transporting the book blocks placed on the transport surface on the one hand and being able to accumulate the book blocks on the transport surface on the other hand while being continuously operated at all times;
• a second conveyor arranged between the exit of the first conveyor and an intake of the bookbinding apparatus so as to supply the book blocks from the first conveyor to the bookbinding apparatus,
• a transport speed of the second conveyor being faster than a transport speed of the first conveyor;
• a first stopper arranged at the exit of the first conveyor, or between the first and second conveyors, or at an entrance of the second conveyor so as to move between a block position at which the first stopper enters a path of the book block so as to stop the book block by making a front end of the book block collide with the first stopper and a retracted position at which the first stopper is retracted from the path of book block;
• a sensor arranged upstream of the first stopper so as to detect the bock block;
• a controller operatively connected to the second conveyor and the first stopper so as to synchronize motion of the second conveyor and the first stopper with the motion of the bookbinding apparatus to take in the book block based on both a detection signal of the sensor and a preparation completion signal of taking in the book block-received from the bookbinding apparatus, characterized in that
• the book block conveying device further comprises:
• a second stopper arranged in the middle of the path of book block on the transport surface of the first conveyor so as to be movable between a block position at which the second stepper enters the path of book block and stops the book block by making the front end of the book block collide with the second stopper and a retracted position at which the second stopper is retracted from the path of book block,
• the controller being operatively connected to the second stopper;
• and
• a detection unit arranged upstream and/or downstream of the second stopper and connected to the controller so as to detect passage and thickness of the book block, wherein
• the controller includes
• a first monitoring section monitoring the number of the book blocks accumulated on upstream side of the first stopper based on book block passage detection signals of the detection unit or based on both the book block passage detection signals of the detection unit and detection signals of the sensor, and outputting a first restriction signal when the number of the book blocks exceeds a predetermined limit value,
• a second monitoring section calculating a thickness difference between the book blocks transported side by side based on thickness detection signals of the detection unit, and outputting a second restriction signal when the thickness difference exceeds a predetermined reference value, and
• a stopper control section sending a first control signal to the second stopper located at the retracted position so as to have the second stopper take the block position when the stopper control section receives the first or the second restriction signal.