Electrostatic imaging device having means for removing undesirable particles from a brush charger and transcribing roller

An electrostatic imaging device comprising:

• a rotating cylindrical photoreceptor drum;
• a transcribing roller, disposed in operable relationship with said photoreceptor drum to form a nip portion therebetween for passing a recording sheet;
• an exposure unit for irradiating said photoreceptor drum to form a latent image thereon during an image forming period;
• a developing unit for supplying electrified toner to said photoreceptor drum to form a toner pattern;
• a brush charger, disposed in operative relationship with said photoreceptor drum, for electrifying said photoreceptor drum during the image forming period;
• and
• a control unit for controlling an application of power from a first power source, said first power source applying a first voltage to said transcribing roller and said brush charger, said transcribing roller electrifying a predetermined point of said photoreceptor drum, said control unit controlling an application of power from a second power source, said second power source applying a second voltage to said brush charger when the predetermnined point of said photoreceptor drum rotates to said brush charger, said second voltage being lower in absolute magnitude than said first voltage and having a same polarity of said first voltage, thereby causing undesirable particles on said brush charger to migrate onto said photoreceptor drum, while said first voltage is maintained for said transcribing roller,
• wherein said control unit applies a third voltage to said transcribing roller after a brush cleaning step, for initiating a transcribing roller cleaning step, said third voltage having a polarity opposite to the polarity of said first voltage for causing undesirable particles on said transcribing roller to migrate onto said photoreceptor drum before a recording sheet is introduced to said nip portion, and wherein said first voltage is applied to said brush charger during said transcribing roller step.