Low-Friction single component development apparatus

A color electrostatographic reproduction machine for producing color toner images without image scavenging defects, the color electrostatographic reproduction machine comprising:

• (a) a moveable image bearing member having an image bearing surface;
• (b) means including charging and exposure means for forming latent images electrostatically on said image bearing surface;
• and
• (c) low-friction single component development apparatus forming a development zone with said image bearing surface for developing electrostatic latent images on said image bearing surface without image scavenging defects, the low-friction single component development apparatus comprising:
• (i) a sump containing a supply of developer material particles;
• (ii) a moveable donor member assembly including a donor member for transporting developer material particles from said sump through a development zone adjacent said image bearing surface, said donor assembly includes a series of isolated electrodes protruding above said donor member;
• (iii) a first combination of AC and DC biases for charging said supply of developer material particles in said sump resulting in charged developer material particles having a desired polarity and charge distribution;
• (iv) a second combination of AC and DC biases for providing fringe electric fields for depositing particles of said charged developer material particles onto said donor member;
• (vi) means for forming a cloud of said charged developer material particles on said donor member, within said development zone, for latent image development;
• and
• (vi) an electrostatic filtering zone located upstream of said development zone relative to movement of said moveable donor assembly for electrostatically removing wrong-sign charged developer material particles from said donor member, thereby controlling and maintaining said desired polarity and charge distribution of said developer material particles within said sump.