US 11,868,062 B2
Developing roller of electrophotographic device without prone to scumming in a nonprinting area
Taku Yamoto, Hyogo (JP); Kimiya Goto, Hyogo (JP); and Hideki Norisada, Hyogo (JP)
Assigned to BANDO CHEMICAL INDUSTRIES, LTD., Hyogo (JP)
Appl. No. 17/606,453
Filed by BANDO CHEMICAL INDUSTRIES, LTD., Hyogo (JP)
PCT Filed Jun. 30, 2020, PCT No. PCT/JP2020/025603
§ 371(c)(1), (2) Date Oct. 26, 2021,
PCT Pub. No. WO2021/006106, PCT Pub. Date Jan. 14, 2021.
Claims priority of application No. 2019-127777 (JP), filed on Jul. 9, 2019.
Prior Publication US 2022/0197182 A1, Jun. 23, 2022
Int. Cl. G03G 15/08 (2006.01)
CPC G03G 15/0818 (2013.01) [G03G 15/0808 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A developing roller having two end portions and a central portion disposed between the two end portions in an extension direction of an axial, comprising an elastic layer, a coat layer formed on the elastic layer, and end portion coat layers only formed on outermost surfaces on the two end portions, wherein
the end portion coat layer comprises a conductive material,
a ratio (Ω1/Ω2) of a resistance value Ω1 at an axial central part of the end portion coat layer to a resistance value Ω2 at an axial central part of the coat layer is 1.6 or less, and
an absolute value (|Ω1−Ω2|) of a difference between the resistance value Ω1 at the axial central part of the end portion coat layer and the resistance value Ω2 at the axial central part of the coat layer is 0.7 GΩ or less.