The inventive developing roller (1) includes a roller body (2) having an outer peripheral surface (5) which includes a surface roughness component including a multiplicity of asperities and having a void volume Vv of not greater than 0.5 ml/m.sup.2, and a surface waviness component including a multiplicity of asperities having a longer periodicity than the surface roughness component and having a void volume Vv of not less than 0.05 ml/m.sup.2 and not greater than 3.5 ml/m.sup.2, the void volumes Vv being each defined as the sum Vvc+Vvv of a core void volume Vvc and a dale void volume Vvv. The inventive production method includes the steps of: polishing the outer peripheral surface (5); and finishing the polished outer peripheral surface by at least one method selected from the group consisting of a laser processing method, a wet blasting method and a dry blasting method, so that the outer peripheral surface has a surface geometry satisfying the requirements for the void volumes Vv.

The inventive developing roller (1) includes a roller body (2) having an outer peripheral surface (5) which includes a surface roughness component including a multiplicity of asperities and having a void volume Vv of not greater than 0.5 ml/m.sup.2, and a surface waviness component including a multiplicity of asperities having a longer periodicity than the surface roughness component and having a void volume Vv of not less than 0.05 ml/m.sup.2 and not greater than 3.5 ml/m.sup.2, the void volumes Vv being each defined as the sum Vvc+Vvv of a core void volume Vvc and a dale void volume Vvv. The inventive production method includes the steps of: polishing the outer peripheral surface (5); and finishing the polished outer peripheral surface by at least one method selected from the group consisting of a laser processing method, a wet blasting method and a dry blasting method, so that the outer peripheral surface has a surface geometry satisfying the requirements for the void volumes Vv.

It is an object of the present invention to provide a development roll rubber member that has a uniformly roughened surface on a rubber member surface, that is capable of ensuring a sufficient thickness without contaminating a peripheral portion while maintaining a flexibility in a coating layer and a convex portion without impairing softness of a rubber substrate layer, and that has the coating layer achieving non-tackiness and low friction, and a method of manufacturing the same, and the object is achieved by putting a reactive silicone oil, an isocyanate compound, and a diluent solvent capable of dissolving both the reactive silicone oil and the isocyanate compound into a reaction container, by causing a prepolymerization reaction in which the reactive silicone oil and the isocyanate compound are reacted into a polymerized state in the diluent solvent in the reaction container while dissolution in the solvent is maintained, by subsequently mixing a polyol and an isocyanate compound solution and using silicone rubber particles 101 to prepare an application liquid of a coating layer 13 component, and by applying and curing the application liquid around the development roll 1 for formation.

A developing device includes a development container, a developer carrying member, and a regulation blade. The development container is for containing a non-magnetic one-component developer composed only of the toner. The developer carrying member is manufactured by a polishing method and includes a rotary shaft and a roller portion stacked on an outer circumferential surface of the rotary shaft, and a toner layer is formed on the roller portion. The regulation blade contacts the outer circumferential surface of the roller portion so as to regulate a thickness of the toner layer. When ten-point average roughnesses in a circumferential direction and in an axial direction of the roller portion are indicated as Rz1 and Rz2, respectively, Rz1/Rz21.5 is satisfied, and a contact linear pressure of the regulation blade with respect to the roller portion is not less than 15 [N/m] and not more than 40 [N/m].

It is an object of the present invention to provide a development roll rubber member that has a uniformly roughened surface on a rubber member surface, that is capable of ensuring a sufficient thickness without contaminating a peripheral portion while maintaining a flexibility in a coating layer and a convex portion without impairing softness of a rubber substrate layer, and that has the coating layer achieving non-tackiness and low friction, and a method of manufacturing the same, and the object is achieved by putting a reactive silicone oil, an isocyanate compound, and a diluent solvent capable of dissolving both the reactive silicone oil and the isocyanate compound into a reaction container, by causing a prepolymerization reaction in which the reactive silicone oil and the isocyanate compound are reacted into a polymerized state in the diluent solvent in the reaction container while dissolution in the solvent is maintained, by subsequently mixing a polyol and an isocyanate compound solution and using silicone rubber particles 101 to prepare an application liquid of a coating layer 13 component, and by applying and curing the application liquid around the development roll 1 for formation.

A toner supply roller is provided which has the most uniform and greatest possible foam cell diameters and a lower hardness particularly even in a lower-temperature and lower-humidity environment as compared with the conventional art and is less liable to suffer from imaging failure such as uneven density and white streaks. An image forming apparatus employing the toner supply roller is also provided. The toner supply roller (1) is produced by preparing a rubber composition which contains a rubber component including an epichlorohydrin rubber and an acrylonitrile butadiene rubber, an electrically conductive carbon black, a crosslinking component and a foaming component and, while extruding the rubber composition into a tubular body, continuously foaming and crosslinking the rubber composition of the tubular body by a continuous crosslinking apparatus including a microwave crosslinking device and a hot air crosslinking device. The image forming apparatus incorporates the toner supply roller (1).

An electrophotographic roller comprising a substrate having a conductive outer surface and a resin layer on a side of the outer surface of the substrate, in which the volume resistivity of the outer surface of the electrophotographic roller is 1.010.sup.6 .Math.cm or higher, when a corona discharger having a grid part is relatively moved along the axial direction of the electrophotographic roller to charge the electrophotographic roller, and the potentials of the outer surface after 0.06 seconds from passage of the grid part are measured, a maximum value of the potentials is lower than 20.0 V, the ionization potential of the outer surface of the electrophotographic roller is 5.0 to 5.6 eV, and an elastic modulus E1 in a region from the outer surface of the electrophotographic roller to a depth of 0.1 m is 200 MPa or higher.

A magnet roller includes a shaft, a first magnet piece, and a second magnet piece. The first magnet piece and the second magnet piece are bonded to an outer circumference of the shaft with an adhesive. The first magnet piece has a first surface and a recessed portion. The recessed portion is recessed with respect to the first surface. The second magnet piece has a second surface and a convex portion. The second surface is held in contact with the first surface. The convex portion protrudes with respect to the second surface. The convex portion fits into the recessed portion.

A developing apparatus including: a toner having a toner particle and an external additive; a toner carrying member used for carrying the toner; and a charging member used for injecting charge into the toner, in which the external additive includes a fine particle A and a fine particle B, the fine particle A is at least one fine particle selected from a group consisting of a silica fine particle and a silicone fine particle, the fine particle B is a specific conductive fine particle, the toner carrying member is a developing roller having: a substrate having an outer surface having conductivity; and a resin layer on the outer surface of the substrate, and impedance of the outer surface of the developing roller and a maximum value of electric potential of the outer surface are in specific ranges.

A developer carrying member includes a shaft, a magnet, a sleeve, a flange, and adhesive. The flange has a first fitting portion, a second fitting portion, and a groove portion. The adhesive is disposed in the groove portion. A first groove portion and a second groove portion are formed continuously in this order from the first fitting portion side to the second fitting portion side. The height from the bottom surface of the second groove portion to the outer circumferential surface of the first fitting portion is greater than that from the bottom surface of the first groove portion to the outer circumferential surface of the first fitting portion.