Belt breaking mechanism for book binding machine

The utility model discloses a belt breaking mechanism for a book binding machine, which comprises a mounting plate, a mounting table is fixedly mounted at the upper end of the mounting plate close to the rear side, a belt breaking air cylinder is fixedly mounted at the upper end of the mounting table, a sliding rail is fixedly mounted at the front end of the mounting table, a sliding block is slidably arranged in the sliding rail, and a belt breaking air cylinder is fixedly mounted at the lower end of the sliding block. A movable block is fixedly arranged at the front end of the sliding block, an upper belt breaking cutter is fixedly arranged at one end of the movable block, a lower fixing block is arranged at the position, close to the lower side of the upper belt breaking cutter, of the upper end of the mounting plate, a lower belt breaking cutter is arranged at one end of the lower fixing block, and the upper belt breaking cutter and the lower belt breaking cutter are located on the same vertical line. Acc