A printer includes a hanger, a printer head, a carriage, and an adjustment assembly. The hanger includes a base and a board above the base. The carriage includes a body, a rod, and an actuator. The body is rotatably connected to the rod. The actuator is rotatably connected to the body. The actuator includes a projection and a resisting member. The adjustment assembly includes a protruding post. When the body moves in a first direction, the projection applies a push force to the protruding post, the protruding post rotates downward. When the body moves in a reverse, second direction, the protruding post applies a push force to the projection, which causes the actuator to rotate, the lateral surface of the resisting member stays in contact with the board during the rotation of the actuator, causing the carriage to rotate, the distance between the printer head and the base is changed.