DEVELOPING ROLL AND DEVELOPING DEVICE PROVIDED THEREWITH

• Main Authors: NAKAMURA MAKOTO, TAKANO YOSHIYUKI
• Format: Patent
• Language: English
• Published: 14.08.2002
• Edition: 7
• Subjects: BEARINGS; BLASTING; CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; ELEMENTS OR CRANKSHAFT MECHANISMS; ENGINEERING ELEMENTS AND UNITS; FLEXIBLE SHAFTS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; HOLOGRAPHY; LIGHTING; MAGNETOGRAPHY; MECHANICAL ENGINEERING; PHOTOGRAPHY; PHYSICS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; SHAFTS; THERMAL INSULATION IN GENERAL; WEAPONS

PROBLEM TO BE SOLVED: To provide a developing roll by which the inclination of developing γis made to be steep even when the surface of the roll is worn with the lapse of time and also toner is saturated at developing potential being low potential of <=150 V and whose durability is improved, and a developing device provided therewith. SOLUTION: This developing roll 10 is successively provided with a core shaft 1, an elastic layer 2 and a surface layer 3, and its volume resistance at an initial stage is set to <=1.5×104 Ωcm, its capacitance at the initial stage is set to >=1.5×10-4 F/m2, and besides, the volume resistance after the 75% of the surface layer 3 is worn is set to <=1.5×106 Ωcm, and also the capacitance after the 75% of the surface layer 3 is worn is set to >=1.0×10-6 F/m2. The JIS-A hardness of the roll 10 is desirably 25 to 50. The thickness of the surface layer of the roll 10 is desirably <=30 μm, and the ASKER-C hardness of the roll 10 including the surface layer is desirably <=55 (303 g load).