Abstract: A method for preparing a silicone elastomer porous material includes the steps of (1) providing a water-in-oil emulsion including a liquid silicone rubber material which forms a silicone elastomer upon curing, a silicone oil material that has a surface activation function, and water droplets dispersed in the liquid silicone rubber material, (2) subjecting the emulsion to a primary heating, thereby curing the liquid silicone rubber material to form a silicone elastomer and confining the water droplets within the silicone elastomer substantially as they are present in the emulsion, and (3) subjecting the silicone elastomer to a secondary heating, thereby evaporating and removing the water droplets from the silicone elastomer, thereby forming the silicone elastomer porous material.

Abstract: A water-in-oil emulsion composition for forming a silicone elastomer porous material contains a liquid silicone rubber material which forms a silicone elastomer upon curing, a silicone oil material which has a surface activation function, and water.

Abstract: A method for preparing a silicone elastomer porous material includes the steps of (1) providing a water-in-oil emulsion including a liquid silicone rubber material which forms a silicone elastomer upon curing, a silicone oil material that has a surface activation function, and water droplets dispersed in the liquid silicone rubber material, (2) subjecting the emulsion to a primary heating, thereby curing the liquid silicone rubber material to form a silicone elastomer and confining the water droplets within the silicone elastomer substantially as they are present in the emulsion, and (3) subjecting the silicone elastomer to a secondary heating, thereby evaporating and removing the water droplets from the silicone elastomer, thereby forming the silicone elastomer porous material.

Abstract: A method of producing a developing roller, includes providing a roller core having an electrically conductive layer provided on a circumferential surface thereof, applying a reaction mixture containing a fluorine-containing polyol, an isocyanate compound, and a reactive silicone oil having an active hydrogen to a surface of the conductive layer, and subjecting the reaction mixture to a reaction condition for reacting the flourine-containing polyol and the reactive silicone oil with the isocyanate compound.

Abstract: A substantially closed-cell silicone elastomer porous body includes cells with diameters of 50 ?m or less, which occupy 50% or more of all the cells, and has a closed cell rate of 60% or more.

Abstract: A water-in-oil emulsion composition for forming a silicone elastomer porous material contains a liquid silicone rubber material which forms a silicone elastomer upon curing, a silicone oil material which has a surface activation function, and water.

Abstract: A developing roller has a roller core, an electrically conductive layer provided on a circumferential surface of the roller core, and a covering layer provided on the outer circumferential surface of the conductive layer. The covering layer is formed by subjecting a reaction mixture containing a fluorine-containing polyol, a reactive silicone oil having an active hydrogen, and an isocyanate compound, to a reaction condition for reacting the fluorine-containing polyol and the reactive silicone oil with the isocyanate compound.

Abstract: A developing roller is provided with a roller core, an electrically conductive layer provided on a circumferential surface of the roller core, and a covering layer provided on the outer circumferential surface of the conductive layer. The covering layer has a thickness of 30 &mgr;m or less, but 0.1 &mgr;m or more, and has at least its surface region formed of a porous body.

Abstract: A method of producing a developing roller, includes providing a roller core having an electrically conductive layer provided on a circumferential surface thereof, applying a reaction mixture containing a fluorine-containing polyol, an isocyanate compound, and a reactive silicone oil having an active hydrogen to a surface of the conductive layer, and subjecting the reaction mixture to a reaction condition for reacting the flourine-containing polyol and the reactive silicone oil with the isocyanate compound.

Abstract: A developing roller has a roller core, an electrically conductive layer provided on a circumferential surface of the roller core, and a covering layer provided on the outer circumferential surface of the conductive layer. The covering layer is formed by subjecting a reaction mixture containing a fluorine-containing polyol, a reactive silicone oil having an active hydrogen, and an isocyanate compound, to a reaction condition for reacting the fluorine-containing polyol and the reactive silicone oil with the isocyanate compound.

Abstract: A developing roller is provided with a roller core, an electrically conductive layer provided on a circumferential surface of the roller core, and a covering layer provided on the outer circumferential surface of the conductive layer. The covering layer has a thickness of 30 &mgr;m or less, but 0.1 &mgr;m or more, and has at least its surface region formed of a porous body.

Abstract: A developing roller is provided with a roller core, an electrically conductive layer provided on a circumferential surface of the roller core, and a covering layer provided on the outer circumferential surface of the conductive layer. The covering layer has a thickness of 30 &mgr;m or less, but 0.1 &mgr;m or more, and has at least its surface region formed of a porous body.

Abstract: A developing roller is provided with a roller core, an electrically conductive layer provided on a circumferential surface of the roller core, and a covering layer provided on the outer circumferential surface of the conductive layer. The covering layer has a thickness of 30 &mgr;m or less, but 0.1 &mgr;m or more, and has at least its surface region formed of a porous body.

Abstract: A porous covering layer is formed on a substrate by applying a reaction mixture containing a polyol, an isocyanate compound, and a pore forming agent including a volatile silicone oil onto a surface of the substrate. The reaction mixture is subjected to a condition under which the polyol reacts with the isocyanate compound.

Abstract: A developing roller has a core bar, an electrically conductive layer formed on the circumferential surface of the core bar, and a covering layer formed on the circumferential surface of the conductive layer. The covering layer includes a reaction product produced by subjecting a reaction mixture containing a polyol, an isocyanate compound and a both-terminal reactive silicone oil to a reaction condition for them, and has a dynamic friction coefficient against paper of 0.9 or more and less than 1.2.

Abstract: An electroconductive roller which is to be installed in an image forming apparatus is provided with a core, a roller body which includes an elastic member having conductivity, and is provided on the outer circumference of said core, and an electroconductive coating layer covering an outer circumferential surface of said roller body. When glossiness of said coating layer is measured, a difference between common logarithms of a maximum value and a minimum value of measurement values is less than 0.1.