Disclosed is a corrugated paperboard printer comprising a chamber which reserves ink, wherein the chamber comprises a chamber frame comprising an ink reservoir which reserves the ink. A steel member and a recovery pipe are arranged on the opposite side of an anilox roll across the chamber frame. The steel member comprises a web extending in an up-down direction, and a first flange and a second flange connected, respectively, to up-down directional opposite ends of the web. The web is penetratingly formed with a maintenance opening in accordance with the position of a coupling port valve or the like. The second flange is formed with an insertion part for allowing the recovery pipe or the like to be inserted therein.