Flexographic printer

A corrugated board box making machine, comprising:

• a flexographic printer in which ink supplied into a nip portion of inking rolls including a rubber roll and an anilox roll is transferred via the anilox roll onto a printing die fitted around the outer circumferential face of a printing cylinder and is further transferred onto the surface of a sheet running between the printing cylinder and an impression roll, thereby a printing is made, comprising an inking roll cover surrounding said inking rolls and forming a gap between itself and said printing cylinder and a static pressure forming means for supplying air into said inking roll cover while printing and forming a slightly higher static pressure within said inking roll cover than that of the peripheral area such that air is ejected through said gap and dust and scraps are prevented from entering the inking roll cover through said gap, a discharge unit which discharges corrugated board sheets from the flexographic printer, a cutting unit which cuts the corrugated board sheets discharged from the discharge unit, wherein said static pressure forming means includes a pressure tank provided at said inking roll cover and connected to the inside of said inking roll cover, a filter provided at an air intake of said pressure rank and a pressurized air supply means provided within said pressure rank on the inner side of said filter, and wherein said pressure tank has an interior space that is connected to the interior of said inking roll cover through an air vent, the air vent being a slit which extends generally parallel to an axial direction of the printing cylinder.