Abstract: An ink jet printer may include an ink jet head, a cam member, a cam follower, and a valve operation mechanism. The ink jet head may comprise an ink chamber, an exhaust passage communicating with the ink chamber, and an exhaust valve disposed at the exhaust passage. The cam member may comprise a cam groove and be configured to rotate. The cam groove may comprise first, second and third grooves. The second groove and the third groove may branch from one end of the first groove. The cam follower may be configured to be guided along the cam groove. The valve operation mechanism may be coupled to the cam follower. In a state where the cam follower is present in a predetermined position in the third groove, the valve operation mechanism may make contact with the exhaust valve, and the exhaust valve may be in an opened state.

Abstract: An image-forming device includes a main casing, a drum unit, an image-forming unit, and a transfer unit. The drum unit is detachable from the main casing and includes a photosensitive drum having a rotational axis extending in an axis direction. The drum unit is formed with a plurality of symbols juxtaposed along the axis direction. The image-forming unit forms an image on the photosensitive drum in an image-forming mode. The transfer unit transfers the first developer image onto the photosensitive drum onto a sheet. The image-forming unit forms a first developer image on the photosensitive drum in a maintenance mode. The first developer image transferred onto the sheet divides the sheet into a plurality of regions along the axis direction, the plurality of regions corresponding to the plurality of symbols, respectively.

Abstract: An image-forming device includes a main casing, a drum unit, an image-forming unit, and a transfer unit. The drum unit is detachable from the main casing and includes a photosensitive drum having a rotational axis extending in an axis direction. The drum unit is formed with a plurality of symbols juxtaposed along the axis direction. The image-forming unit forms an image on the photosensitive drum in an image-forming mode. The transfer unit transfers the first developer image onto the photosensitive drum onto a sheet. The image-forming unit forms a first developer image on the photosensitive drum in a maintenance mode. The first developer image transferred onto the sheet divides the sheet into a plurality of regions along the axis direction, the plurality of regions corresponding to the plurality of symbols, respectively.

Abstract: An ink jet printer may be provided with an ink jet head, a cam member, a cam follower, and a valve operation mechanism. The ink jet head may comprise an ink chamber, an exhaust passage communicating with the ink chamber, and an exhaust valve disposed at the exhaust passage. The cam member may comprise a cam groove. The cam member may be configured to rotate. The cam groove may comprise a first groove, a second groove, and a third groove. The second groove and the third groove may branch from one end of the first groove. The cam follower may be configured to be guided along the cam groove. The valve operation mechanism may be coupled to the cam follower. In a state where the cam follower is present in a predetermined position in the third groove, the valve operation mechanism may make contact with the exhaust valve, and the exhaust valve may be in an opened state.