An image forming apparatus having a liquid ejection head including a plurality of nozzles for ejecting droplets and a plurality of piezoelectric elements for generating a pressure for discharging droplets in respective nozzles. The process involves polymerization of esters of p-hydroxystyrene, alkyl acrylate monomers andor one or more of ethylenically unsaturated monomers in an alcohol solvent in the presence of a free radical initiator. In the alternative, the tube may be of a pre-determined length. The second controller provides the switching signal to the sensor array. Lights having wavelength bands different from each other are independently detected according to disclosed invention. The microfabricated fluidic unidirectional valve also includes an elastomer flap attached to the elastomer material in the flow through channel.