Abstract: In a toner having toner particles which have toner base particles having at least a colorant and a binder resin, and an inorganic fine powder; the inorganic fine powder has a primary-particle average particle diameter of from 30 nm to 300 nm, and has particles having at least one of a cubic particle shape, a cube-like particle shape, a rectangular particle shape and a rectangle-like particle shape and having perovskite type crystals; and the inorganic fine powder has particles and agglomerates both having particle diameters of 600 nm or more, in a content of 0% to 1% by number.

Abstract: A toner suitable for use in an image forming method including a contact charging step is provided. The toner includes: toner particles comprising at least a binder resin and a colorant, and fine particles. The fine particles comprise: (i) a tungsten-containing tin oxide, or (ii) base particles, and a tungsten-containing tin compound coating the base particles, the fine particles contain tin (Sn) in a weight ratio (Sn/b) of 0.01 to 2.0 with respect to the base particles (B). In the fine particles, tungsten (W) is contained in a mol ratio (W/Sn) of 0.001 to 0.3 with respect to the tin (Sn).

Abstract: In a toner having toner particles which have toner base particles having at least a colorant and a binder resin, and an inorganic fine powder; the inorganic fine powder has a primary-particle average particle diameter of from 30 nm to 300 nm, and has particles having at least one of a cubic particle shape, a cube-like particle shape, a rectangular particle shape and a rectangle-like particle shape and having perovskite type crystals; and the inorganic fine powder has particles and agglomerates both having particle diameters of 600 nm or more, in a content of 0% to 1% by number.

Abstract: A toner suitable for use in an image forming method including a contact charging step is provided. The toner includes: toner particles comprising at least a binder resin and a colorant, and fine particles. The fine particles comprise: (i) a tungsten-containing tin oxide, or (ii) base particles, and a tungsten-containing tin compound coating the base particles, the fine particles contain tin (Sn) in a weight ratio (Sn/b) of 0.01 to 2.0 with respect to the base particles (B). In the fine particles, tungsten (W) is contained in a mol ratio (W/Sn) of 0.001 to 0.3 with respect to the tin (Sn).

Abstract: Magnetic particles for charging an image-bearing member electrostatically. The charging magnetic particles have magnetic particles, first surface coat layers containing a first surface coating agent and covering the surfaces of the magnetic particles and second surface coat layers containing a second surface coating agent and covering the first surface coat layers. The charging magnetic particles contain magnetic particles for charging which have a maximum chord length of 5 &mgr;m or larger, and the magnetic particles for charging which have a maximum chord length of 5 &mgr;m or larger having a minor-axis length/major-axis length standard deviation of 0.08 or more. Also, a process for producing the charging magnetic particles is disclosed together with a charging member, a process cartridge and an image forming apparatus which make use of the charging magnetic particles.

Abstract: An electrophotographic apparatus includes an electrophotographic photosensitive member, and (i) a charger, (ii) an imagewise exposure device, (iii) a developing device and (iv) a transfer device, disposed in this order opposite to the photosensitive member. The charger includes a charging member including magnetic particles disposed in contact with the photosensitive member so as to charge the photosensitive member based on a voltage received thereby. The magnetic particles are surface-coated with a coupling agent having a linear alkyl group having a least 6 carbon atoms. The developing device also functions to recover residual toner remaining on the photosensitive member processing by the transfer device and the charger. Because of the coating with such a specific coupling agent, the charging magnetic particles can exhibit good triboelectric changeability for the transfer residual toner for a long period.

Abstract: A magnetic particle for charging is disclosed. The magnetic particle includes magnetic particles having particle diameters of 5 .mu.m or more. The magnetic particles having particle diameters of 5 .mu.m or more have a standard deviation of short-axis length/long-axis length of 0.08 or more, and a volume resistance value in the range of 10.sup.4 to 10.sup.9 .OMEGA.cm. Also, provided are a charging member, a charging device, a process cartridge and an electrophotographic apparatus, using the magnetic particle.

Abstract: An electrophotographic apparatus includes: an electrophotographic photosensitive member, a charging device including a charging member formed of magnetic particles and disposed contactable to the photosensitive member so as to charge the photosensitive member based on a voltage applied thereto, exposure device, developing device, and a transfer device. The magnetic particles exhibit a good charging ability for a long period and therefore provide a good continuous image-forming performance because they are formed of ferrite particles including a ferrite having a very limited composition represented by the formula of:(MnO).sub.x (MgO).sub.y (Fe.sub.2 O.sub.3).sub.z,wherein x, y and z are numbers satisfying x+y+z.ltoreq.1, 0.2<x<0.5, 0.05<y<0.25 and 0.4<z<0.6, and 0.01-3 wt. parts of phosphorus added per 100 wt. parts of the ferrite and contained preferentially at a larger concentration at the surfaces of the magnetic particles than in the entirety of the magnetic particles.

Abstract: A charging apparatus which comprises an electrophotographic photosensitive member and a charging member which comprises magnetic particles and placed in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member upon application of a voltage, wherein each magnetic particle has a surface layer containing a polyolefin resin of which weight average molecular weight is 10,000 or more, and has a volume resistivity of 1.times.10.sup.4 to 1.times.10.sup.11 .OMEGA.cm.

Abstract: A charging member, which electrically charges an object to be charged by being placed in contact with the object to be charged and by being applied with a voltage, is provided where the charging member includes an electroconductive base and brush bristles to come into contact with the object to be charged, and the brush bristles include at least one of etching fibers and divided fibers.

Abstract: A charging member includes a conductive substrate and a surface layer which is to be brought into contact with a member to be charged. On the surface layer a raised fiber entangled material is provided.

Abstract: A charging apparatus or an electrophotographic apparatus includes an electrophotographic photosensitive member including a photosensitive layer provided on a conductive supporting member, and a charging member including magnetic particles, disposed to be in contact with the electrophotographic photosensitive member, for charging the electrophotographic photosensitive member when a voltage is applied to the charging member. The layer of the electrophotographic photosensitive member most separated from the conductive supporting member has a volume resistivity between 10.sup.8 .OMEGA..cm and 10.sup.15 .OMEGA..cm, and the magnetic particles have a hygroscopic property such that the ratio H/L of the maximum value H to the minimum value L of the amount of water contained within the particles is at least 1 and less than 4.

Abstract: An image forming apparatus includes a movable image bearing member; an image forming device for forming a toner image on the image bearing member; a charging member for charging the image bearing member in a charging station; and an electrical power source for supplying power to the charging member. A detector detects the voltage-current characteristic between the charging member and the image bearing member; and a controller controls the output of the electrical power source, in accordance with an output of the detector, when a surface area portion of the image bearing member, where the toner image is not going to be formed as the image bearing member rotates, is in the charging station.

Abstract: A charging device includes a movable member to be charged; a charging member contactable to the member to be charged to electrically charge the member to be charged; a discharging device, disposed upstream of a contact portion between the charging member and the member to be charged with respect to a movement direction of the member to be charged, for electrically discharging the member to be charged at a portion adjacent to the contact portion.

Abstract: An image forming apparatus includes a movable image bearing member, having a photosensitive layer; an image forming device for forming an image on the image bearing member: a charging member for charging the image bearing member; and a light radiating device for radiating light on the image bearing member; a detector for detecting a datum rotating to a thickness of the photosensitive layer on the basis of the voltage-current characteristic between the charging member and image bearing member; and a controller for controlling the amount of light radiated from the light radiating device to be increased with decrease in the thickness of the photosensitive layer, in response to the detector.

Abstract: A charging device includes a member to be charged, and a charging member for charging the member to be charged. The charging member includes a surface layer which can contact the surface of the member to be charged. A voltage is applied between the member to be charged and the charging member. The contact angle with water .gamma..sub.R of the surface layer of the charging member is greater than the contact angle with water .gamma..sub.D of the surface of the member to be charged. An image forming apparatus includes the above-described charging device.

Abstract: A developing apparatus for developing an electrostatic latent image having a movable developer carrying member for carrying one component developer to a developing zone where the developer carrying member is opposed to a latent image bearing member for carrying the electrostatic latent image, the developer carrying member being effective to triboelectrically charge the developer to a polarity for developing the latent image; a regulating member for regulating a thickness of a layer of the developer to be carried to the developing zone; a voltage source for applying a developing bias voltage to the developer carrying member; wherein the developer carrying member has a base member having a surface sandblasted to have an average surface roughness of 1.0-3.0 microns, and an outer layer thereon in which fine graphite particles are dispersed in a binder resin material, and wherein the outer layer has an average surface roughness of 0.8-2.5 microns.