Developer supporting member, developing roller, developing device, and image forming apparatus
View Patent ↗A developer supporting member includes a supporting layer for supporting developer. The supporting layer has a corona discharge resistivity of a specific value. The supporting layer is formed of an elastic layer and a surface layer. The surface layer includes a surface treated with a urethane solution.
1. A developer supporting member comprising:
a supporting layer for supporting developer, said supporting layer having a corona discharge resistivity having a common logarithm value of less than 7.89 (log Ω).
2. The developer supporting member according to claim 1 , wherein said supporting layer is formed of an elastic layer and a surface layer.
3. The developer supporting member according to claim 2 , where said surface layer includes a surface treated with a urethane solution.
4. The developer supporting member according to claim 2 , where said surface layer includes a surface treated with a urethane solution containing fluoride.
5. The developer supporting member according to claim 2 , wherein said elastic layer is formed of a urethane rubber.
6. The developer supporting member according to claim 2 , wherein said elastic layer is formed of a urethane rubber containing carbon black.
7. The developer supporting member according to claim 1 , further comprising a conductive portion, said supporting layer being disposed on the conductive portion.
8. The developer supporting member according to claim 7 , wherein said conductive portion is formed of a shaft.
9. The developer supporting member according to claim 1 , wherein said supporting layer has the corona discharge resistivity having a common logarithm value of less than 7.85 (log Ω).
10. The developer supporting member according to claim 9 , wherein said supporting layer has the corona discharge resistivity having a specific ratio Sr between 0.99 and 1.23, said ratio being expressed with the following equation:
Sr=Rea/Reb
where Rea is an average value of the corona discharge resistivity in an area inside a developing device, and Reb is an average value of the corona discharge resistivity in an area outside the developing device.
11. The developer supporting member according to claim 10 , wherein said supporting layer has the corona discharge resistivity having the specific ratio Sr between 0.99 and 1.15.
12. A developing roller comprising a conductive shaft and the developer supporting member according to claim 1 , said developer supporting member being disposed on the conductive shaft.
13. A developing device comprising the developing roller according to claim 12 .
14. An image forming apparatus comprising the developing device according to claim 13 , and a transfer device for transferring a developer image formed with the developing device.
15. The developer supporting member according to claim 1 , wherein said supporting layer has the corona discharge resistivity having a specific ratio Sr between 0.99 and 1.20, said ratio being expressed with the following equation:
Sr=Rea/Reb
where Rea is an average value of the corona discharge resistivity in an area inside a developing device, and Reb is an average value of the corona discharge resistivity in an area outside the developing device.
16. The developer supporting member according to claim 15 , wherein said supporting layer has the corona discharge resistivity having the specific ratio Sr between 0.99 and 1.14.