An image forming system is disclosed which can prevent toner stain adhered onto an image bearing member at the time of switching from one developing unit to another from adhering to an image area on an intermediate transfer member and which can thereby prevent the deterioration of image quality. Subtraction techniques are described to enhance the processing of the muon tomography data. A first prong extends from the housing and second prong extends from the palm grip, wherein when the palm grip is in the expanded position, the first and second prongs are spaced apart and when the palm grip is moved to the compressed position the second prong is adjacent the first prong. 2-hydroxy-4-methylthiobutanamide is continually hydrolyzed within the plug flow reactor to produce an aqueous hydrolyzate product solution containing 2-hydroxy-4-methylthiobutanoic acid. The separations between phase shifters, or cuts, are designed for easy mask manufacturability while also maximizing the amount of each feature defined by the phase shifting mask.