Patent ID: 11934110

Abstract:
A developing roll has a metal core, an elastic layer, and a surface layer. A value X is 65.6 N/mm3 or more and a value Y is 229 μm or more. The value X is P1/(D1×A)−P2/(D2×A). P1 is the load to displace the roll 100 μm when a metal probe is pressed against the roll. D1 is the displacement of the roll caused by the probe under the load P1. A is the area of the probe. P2 is the load to displace a material roll by 100 μm when the probe presses against the material roll with the core and the elastic layer and without the surface layer. D2 is the displacement of the material roll caused by the probe under the load P2. The value Y is the displacement of the roll when the probe pierces the surface layer.