Abstract: An object of the present invention is to prevent an electrical breakdown of a toner layer and an occurrence of overcurrent, thereby preventing quality of image from being degraded at the time of development, when development with one-component toner is conducted using a developing roller of low resistance. The resistance value Rd of a developing roller which carries and conveys one-component toner in a manner of coming into contact with a photoconductor which bears an electrostatic latent image, is defined as Rd=.rho.d.multidot.(Dd1/S1), wherein S1 (cm.sup.2) is an area in which the developing roller comes into contact with the static image bearing member via a toner layer, Dd1 (cm) is a layer thickness of a semiconductive layer which composes the developing roller, and .rho.d (.OMEGA..multidot.cm) is a volume resistivity thereof. The range of the resistance Rd is set as 10.sup.4 <Rd<10.sup.5 and the resistance Rt (.OMEGA.) of the toner layer is set as Rt>5.times.10.sup.7.

Abstract: A system which phase modulates a carrier to produce a carrier signal which transitions in phase between predetermined phase states as a function of the data, wherein a rate at which the carrier signal changes phase during a transition between the predetermined phase states varies substantially sinusoidally. The phase modulation provides a constant amplitude modulated waveform having low side lobes. Such modulation method preserves the high noise tolerance capabilities associated with FH systems and the high data throughput capabilities of DS systems.