US 12,013,650 B2
Charging roll for electrophotographic apparatus
Yoshihiro Saito, Aichi (JP); Hiroshi Ukai, Aichi (JP); and Masanori Ishida, Aichi (JP)
Assigned to Sumitomo Riko Company Limited, Aichi (JP)
Filed by Sumitomo Riko Company Limited, Aichi (JP)
Filed on Jun. 6, 2023, as Appl. No. 18/330,337.
Application 18/330,337 is a continuation of application No. PCT/JP2022/005776, filed on Feb. 15, 2022.
Claims priority of application No. 2021-025091 (JP), filed on Feb. 19, 2021.
Prior Publication US 2023/0314980 A1, Oct. 5, 2023
Int. Cl. G03G 15/02 (2006.01)
CPC G03G 15/0233 (2013.01) 8 Claims
OG exemplary drawing
 
1. A charging roll for an electrophotographic apparatus, comprising:
a shaft;
an elastic body layer formed on an outer peripheral surface of the shaft; and
a surface layer formed on an outer peripheral surface of the elastic body layer, wherein
grooves which regularly define spirals along an axial direction are formed on the outer peripheral surface of the elastic body layer,
a groove width of the groove is 4 μm or more and 280 μm or less,
a groove depth of the groove is 2 μm or more and 30 μm or less,
on the outer peripheral surface of the elastic body layer, an area ratio a/b between an area a of a bottom surface of the groove and an area b of a plane part, which is a portion other than the groove, is 0.3 or more and 2.4 or less,
the surface layer comprises a binder polymer and a roughness forming particle,
the roughness forming particle is arranged on the plane part and on the groove of the elastic body layer, respectively,
a surface roughness Rz of the surface layer in a region on the groove is 2 μm or more and 16 μm or less,
a surface roughness Rz of the entire surface layer is 5 μm or more and 26 μm or less, and
a thickness of the binder polymer covering the roughness forming particle on the groove is greater than a thickness of the binder polymer covering the roughness forming particle on the plane part.