In an MFP, when a count of printed sheets of paper exceeds a predetermined count, a controller reads, from internal counters, a frequency of a stabilization process executed in return, a frequency of a stabilization process executed automatically in printing, a frequency of a stabilization process executed manually based on a user’s instruction, and a frequency of return, respectively. One end of the rocker arm is actuated by a push rod to actuate a valve stem of a poppet valve that engages the other end of the rocker arm, which is pivotably held between its ends on a support pin that extends into the cylinder head, with a spherical mounting being provided between the support pin and the rocker arm. A valve body may adjust the amount of liquid emitted from the at least one drive outlet. Solids are moved towards a periphery of the tube where a cone collector facilitates to collect the solids.