A planning system and method is disclosed. The framing member has aligned stem receiving holes with the upper hole being on an outwardly domed frusto-conical shaped area and the lower hole is on an inwardly dimpled area of the lower frame wall. By varying the number of pulses in a control burst, the total current flowing through the light source may be precisely controlled providing greater accuracy than other methods, such as, for example, PWM or variable pulse frequency. The assignment control section determines a print destination for processed print data subjected to image processing by the image processing section from the image forming apparatus of its own and the at least one external image forming apparatus. A failure of the position control system is detected based upon a difference or a ratio between an integral value A of the target position and an integral value B of the actual position thereof.