Elastic body of an addition reaction type silicone rubber elastic material used in elastic roller and fixing device

The elastic roller for fixing an unfixed toner image carried by a recording sheet onto said recording sheet, comprising:

• a core member, and an elastic layer formed on a surface of said core member, said elastic layer being formed from an addition reaction type silicone rubber elastic material obtained by curing a polysiloxane mixture;
• said polysiloxane mixture including at least
• (a) a straight-chain dimethyl polysiloxane having a viscosity of 80,000 poise or more at a temperature of 25.degree. C. and terminated with vinyl groups;
• and
• (b) a resinous organopolysiloxane having at least two vinyl groups and having a viscosity of 10-1000 poise at a temperature of 25.degree. C. and comprising a block copolymer having a resin segment comprising at least one of a 4-functional constitutional unit and a 3-functional constitutional unit, and a straight-chain oil segment comprising 100 or more continuous 2-functional units in the same molecule.

A fixing device for fixing an unfixed toner image carried on a recording sheet onto said recording sheet by heating and pressing said toner image, comprising:

• a fixing means adapted to pinch, heat and press the recording sheet on which the unfixed toner image is carried comprising a pair of rotatable rollers which are urged against each other and at least one of which has a heating means therein,
• one of said rotatable rollers which contacts with the unfixed toner image being a fixing roller comprising a core member, and an elastic layer formed on a surface of said core member and made of an addition reaction type silicone rubber elastic material obtained by curing polysiloxane mixture;
• said polysiloxane mixture including at least
• (a) a straight-chain dimethyl polysiloxane having a viscosity of 80.000 poise or more at a temperature of 25.degree. C. and terminated with vinyl groups;
• and
• (b) a resinous organopolysiloxane having at least two vinyl groups and having a viscosity of 10-1,000 poise at the temperature of 25.degree. C. and comprising a resin segment comprising a block polymer having at least one of a 4-functional constitutional unit and a 3-functional constitutional unit, and a straight-chain oil segment comprising 100 or more continuous 2-functional constitutional units in the same molecule.