JP2009109745A5 - - Google Patents

Claims (8)

A shaft core,
A conductive elastic layer formed of a cured product of a silicone rubber composition formed around the shaft core;
In a conductive roller having
The elastic layer is
(A) a silicone rubber containing a dimethylpolysiloxane skeleton;
(B) carbon black having a size of aggregated unit of 230 nm or more and 380 nm or less;
(C) carbon black or an inorganic filler having an aggregate unit size of 590 nm to 1210 nm;
Including
The ratio of the occupied area of the component (b) and the component (c) is 1: 1 or more and 1: 4 or less,
And about a curve obtained by differentiating the thermogravimetric decrease curve obtained when the elastic layer is heated from 25 ° C. to 20 ° C./min in a nitrogen atmosphere, within a low temperature range of 360 ° C. or more and 520 ° C. or less, Each having at least one peak in the high temperature side temperature range of 580 ° C. or more and 650 ° C. or less,
P1max (wt% / ° C) is the peak height of the maximum temperature within the low temperature range.
The peak height of the lowest temperature within the high temperature range is P2 min (wt% / ° C),
The lower peak height of P1max and P2min is P3 (wt% / ° C),
P4 (wt% / ° C) for the minimum part between 520 ° C and 580 ° C
When
0.0 ≦ P4 / P3 ≦ 0.9
A conductive roller characterized by the above. The P1max and the temperature difference P2min is 90 ° C. or higher, the conductive roller of claim 1 is 290 ° C. or less. Wherein component (b) and the component in the elastic layer (c), claim 1, characterized in that to said component (a) 100 parts by weight total 12 parts by mass or more, or less 18 parts by mass Or the electroconductive roller of 2. The silicone rubber composition is
A first polysiloxane having at least one alkenyl group at the terminal and having a weight average molecular weight of 60,000 to 100,000, wherein 99 mol% or more of the main chain is a repeating unit of dimethylsiloxane, and at least one terminal A second polysiloxane having an alkenyl group and having a weight average molecular weight of not less than 900,000 and not more than 2 million, in which 99 mol% or more of the main chain is a repeating unit of dimethylsiloxane , has a mass ratio of 1: 1 to 19: 1. The conductive roller according to claim 1, which is included at a ratio of The elastic layer is obtained by applying a coating liquid for forming the elastic layer using a ring-shaped coating head to the periphery of the shaft core, followed by heat curing. conductive roller according to any one of 1 to 4. The conductive roller comprises a conductive roller according to any one of claims 1 to 5 is a developing roller. A developing roller is mounted, a thin layer of toner is formed on the surface of the developing roller, the surface of the photosensitive drum is supplied by bringing the developing roller into contact with the photosensitive drum and supplying the toner to the surface of the photosensitive drum. in an electrophotographic process cartridge for forming a toner image on the electrophotographic process cartridge, wherein the developing roller is a developing roller according to claim 6.   A developing roller is mounted, a thin layer of toner is formed on the surface of the developing roller, the toner is supplied to the surface of the photosensitive drum by bringing the developing roller into contact with the photosensitive drum, and the surface of the photosensitive drum An image forming apparatus for forming a toner image on the image forming apparatus, wherein the developing roller is the developing roller according to claim 6.