The frequency modulation apparatus 2, wherein {HEAD ~ said predetermined fluctuation range} is {TAIL ~ ±2.0%} or less for the reference clock in said image forming area on said image bearing body 
is
The frequency modulation apparatus 2 , wherein { HEAD ~ said predetermined fluctuation range } is { TAIL ~ ±2.0 % } or less for the reference clock in said image forming area on said image bearing body
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH