An image forming apparatus with a double-face printing function is provided. The fine control circuit adjusts a phase of a feedback clock signal by a first phase adjustment in response to a first phase error signal that indicates a sign of a phase error between a reference clock signal and the feedback clock signal. The method can further comprise the steps of: for each GUI element in the GUI, accepting a value; and, formatting a command string containing the accepted values. The liquid paraffin layer coating the heat-sealable layer improves the emboss-formability of the polymer battery module packaging material.