Abstract: A toner according to the present disclosure maintains high transfer efficiency for the long term and obtains images which are not affected by toner base particles easily, which exhibit excellent charge stability, and which exhibit less fogging, wherein the toner is obtained by making inorganic fine particles and charge control particles, which satisfy specific conditions, present on the surfaces of toner base particles so as to satisfy a specific coverage relationship.

Abstract: There is provided a toner including toner base particles and an external additive in which the external additive is prevented from being buried in the base particles. The toner can maintain a high transfer efficiency over an extended period of use. The toner includes: (1) toner base particles containing a cycloolefin copolymer and a polyethylene; or (2) toner base particles whose surfaces contain a resin having an elastic deformation rate of 70% or more and a melting temperature of 125.0° C. or less.

Abstract: There is provided a toner including toner base particles and an external additive in which the external additive is prevented from being buried in the base particles. The toner can maintain a high transfer efficiency over an extended period of use. The toner includes: (1) toner base particles containing a cycloolefin copolymer and a polyethylene; or (2) toner base particles whose surfaces contain a resin having an elastic deformation rate of 70% or more and a melting temperature of 125.0° C. or less.

Abstract: There is provided a toner including toner base particles and an external additive in which the external additive is prevented from being buried in the base particles. The toner can maintain a high transfer efficiency over an extended period of use. The toner includes: (1) toner base particles containing a cycloolefin copolymer and a polyethylene; or (2) toner base particles whose surfaces contain a resin having an elastic deformation rate of 70% or more and a melting temperature of 125.0° C. or less.

Abstract: Provided is a toner, including a toner particle having a core particle containing a binder resin and a colorant. The toner particle has a protrusion on a surface thereof, and the protrusion contains an olefin-based polymer having a cyclic olefin structure. When an average radius of curvature of the protrusion, an average particle diameter of the core particle, a projected area of the toner particle, and a projected area of the protrusion that are calculated from a planar projected image of an image of the toner particle photographed with a scanning electron microscope are represented by Rs (?m), Rc (?m), S, and S1, respectively, the average radius of curvature Rs of the protrusion is 0.004Rc ?m or more and 0.100Rc ?m or less, and an average of a surface coverage “100×S1/S” % is 5% or more and 90% or less.

Abstract: There is provided a toner including toner base particles and an external additive in which the external additive is prevented from being buried in the base particles. The toner can maintain a high transfer efficiency over an extended period of use. The toner includes: (1) toner base particles containing a cycloolefin copolymer and a polyethylene; or (2) toner base particles whose surfaces contain a resin having an elastic deformation rate of 70% or more and a melting temperature of 125.0° C. or less.

Abstract: A toner according to the present disclosure maintains high transfer efficiency for the long term and obtains images which are not affected by toner base particles easily, which exhibit excellent charge stability, and which exhibit less fogging, wherein the toner is obtained by making inorganic fine particles and charge control particles, which satisfy specific conditions, present on the surfaces of toner base particles so as to satisfy a specific coverage relationship.

Abstract: In an image forming apparatus having a photosensitive drum that carries a toner image, a developing roller is provided to be capable of rotating while carrying toner and supplies the toner to the photosensitive drum in order to develop a latent image, and a voltage applying device applies a voltage to the developing roller. The developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

Abstract: A developing roller that is capable of carrying toner on a surface thereof, and that supplies the toner carried on the surface to a surface of a photosensitive drum when a voltage is applied thereto, includes: an elastic layer; and a surface layer that covers the elastic layer and contains aluminum oxide, wherein the aluminum oxide of the surface layer contains tetracoordinated aluminum atoms and hexacoordinated aluminum atoms existing in a higher proportion than the tetracoordinated aluminum atoms.

Abstract: Provided is a toner, including a toner particle having a core particle containing a binder resin and a colorant. The toner particle has a protrusion on a surface thereof, and the protrusion contains an olefin-based polymer having a cyclic olefin structure. When an average radius of curvature of the protrusion, an average particle diameter of the core particle, a projected area of the toner particle, and a projected area of the protrusion that are calculated from a planar projected image of an image of the toner particle photographed with a scanning electron microscope are represented by Rs (?m), Rc (?m), S, and S1, respectively, the average radius of curvature Rs of the protrusion is 0.004Rc ?m or more and 0.100Rc ?m or less, and an average of a surface coverage “100×S1/S” % is 5% or more and 90% or less.

Abstract: In an image forming apparatus having a photosensitive drum capable of carrying a toner image, a developing roller that is provided to be capable of rotating while carrying toner, and that supplies the toner to the photosensitive drum by contacting the photosensitive drum, a regulating blade that regulates a layer thickness of the toner carried on the developing roller, and a voltage applying device for applying a voltage to the developing roller and the regulating blade. The developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

Abstract: In an image forming apparatus having a photosensitive drum that carries a toner image, a developing roller that is provided to be capable of rotating while carrying toner, and that supplies the toner to the photosensitive drum in order to develop a latent image, and voltage applying device for applying a voltage to the developing roller, the developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

Abstract: A developing roller that is capable of carrying toner on a surface thereof, and that supplies the toner carried on the surface to a surface of a photosensitive drum when a voltage is applied thereto, includes: an elastic layer; and a surface layer that covers the elastic layer and contains aluminum oxide, wherein the aluminum oxide of the surface layer contains tetracoordinated aluminum atoms and hexacoordinated aluminum atoms existing in a higher proportion than the tetracoordinated aluminum atoms.

Abstract: In an image forming apparatus having a photosensitive drum capable of carrying a toner image, a developing roller that is provided to be capable of rotating while carrying toner, and that supplies the toner to the photosensitive drum by contacting the photosensitive drum, a regulating blade that regulates a layer thickness of the toner carried on the developing roller, and voltage applying device for applying a voltage to the developing roller and the regulating blade, the developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

Abstract: An image forming apparatus includes a photosensitive member, a first developer carrying member for carrying a developer comprising toner and a carrier for developing an electrostatic image formed on the photosensitive member, and a second developer carrying member for carrying the developer received from the first developer carrying. The second developer carrying member is disposed downstream of the first developer carrying member with respect to a rotational direction of the photosensitive member. In addition, a voltage source applies a developing bias voltage to the first developer carrying member and second developer carrying member, and a driving device rotates the first developer carrying member at a peripheral speed higher than that of the photosensitive member and rotates the second developer carrying member at a peripheral speed which is higher than that of the photosensitive member and which is lower than that of the first developer carrying member.

Abstract: An object of the present invention is to provide a two-component developer which can achieve a high-definition image with a smaller toner laid-on level than a conventional one, provides a color gamut comparable to that of printing, can respond to an increase in printing speed, and allows an image with a stable tinge to be formed even in long-term use. The object can be achieved by a two-component developer containing a cyan toner and a magnetic carrier, the two-component developer being characterized in that the cyan toner has the following characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00<A712/Cc<8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0?L*?40.0 and 50.0?C*?60.

Abstract: A toner containing toner base particles and an external additive, wherein regions with different tribocharging polarities with respect to a magnetic carrier are present in a domain-matrix structure on the surface of the toner base particles. The island region B has a predetermined height, the external additive has a reverse polarity to the region B in terms of tribocharging polarity to the magnetic carrier, the external additive contains a first external additive having a number-average primary particle size of 80-150 nm and a second external additive having a number-average primary particle size of 10-60 nm, and an average coverage Cb (%) with the first external additive in the region B is 27-100% and a coverage Ca (%) with the first external additive in the sea region A is 12% or less.

Abstract: An image forming apparatus includes a photosensitive member, having a capacitance per unit area of 1.7×10?6 (F/m2) or larger, an exposure device, which exposes the photosensitive member in order to form thereon an electrostatic image according to image information, a developing device, which develops the electrostatic image with a toner to form a toner image on the photosensitive member, and a transfer device, which transfers the toner image onto a recording material. In forming a solid toner image on the recording material, the exposure device is capable of forming electrostatic images of different potential levels on the photosensitive member, thereby forming toner images of different toner heights on the photosensitive member.

Abstract: A duty ratio Du (%), denoted by (T2/(T1+T2))×100, is in the range of 60?Du?80; a magnetic carrier has a resistivity ? which decreases in accordance with an increasing electric field strength, and a relative dielectric constant ? which increases in accordance with an increasing electric field strength; a product of a time constant ?0??(s) of electric charge decay in an electric field strength E2D decided by a second peak voltage V2 and a dark potential VD, and an electric field strength E2D satisfies a relation of 20??0?? E2D (s·V/cm); and a time constant ?0??(s) and a relative dielectric constant ? in an electric field strength E1L, which is decided by a first peak voltage V1 and a bright potential VL, satisfy the following relations: ?0??(s)?6.0×10?4, and 30??.

Abstract: A two-component developer containing a cyan toner and a magnetic carrier, the cyan toner having the following characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00<A712/Cc<8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0?L*?40.0 and 50.0?C*?60.0; and (iii) the absolute value for the triboelectric charge quantity of the cyan toner measured by a two-component method using the cyan toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.