A developing apparatus includes a first developing system for developing a latent image formed on an image bearing member with a first developer including magnetic toner. Each blade in the row alternate with another blade having a different pressure surface definition but similar suction surface, leading edge and trailing edge definitions. Thus, a punch-through stopper area is formed in the area in which a submicron CMOS transistor is formed, while preventing the formation of a punch-through stopper area in the area in which an analog CMOS transistor, a high voltage-resistance MOS transistor, a bipolar transistor, a diode, or a diffusion resistor is formed. Also, user modification of control element settings in the logical component sections can be permitted. The lockable bar has an enlarged portion to prevent it from being passed through the orifice in a first direction.