Composite printing structure of corrugated board production line

The invention relates to the technical field of corrugated board production lines, and discloses a corrugated board production line composite printing structure which comprises a rack, a plurality of conveying rollers are rotatably arranged at the upper end of the interior of the rack, the outer sides of the conveying rollers are sleeved with a conveying belt in a transmission mode, grooves are formed in the upper ends of the two sides of the interior of the rack, and sliding plates are slidably arranged in the two grooves; a scraping plate is fixedly arranged between the two sliding plates, a longitudinal adjusting mechanism is arranged between the sliding plates and the rack, a supporting plate is fixedly arranged at the upper end of the outer side wall of the rack, a motor is fixedly arranged at the top of the supporting plate, the roller wall of the conveying roller penetrates out of the rack and extends to the outside, and the output end of the motor and the roller wall of the conveying roller are fixedl