A holding mechanism 40 is made up of a shaft support 44 that is provided while joined to a joint and that has a vertically-oriented pivot 44a, a shaft member 45 that horizontally extends from the shaft support 44 and that is turnable around the pivot 44a, and a fitting section 36 that is formed in a squeegee unit 16 and to which the shaft member 45 is removably fitted. Thereby, the entirety of the squeegee unit 16 becomes removably attachable by only moving the squeegee unit 16 in a horizontal direction.