Abstract: The present invention provides a one-component magnetic toner for developing an electrostatic charge image, which do not cause an image defect by toner aggregation or fusion even though a device is miniaturized and the processing speed of the device is accelerated, and which allows easy recycling of a toner cartridge. The one-component magnetic toner for developing an electrostatic charge image of the present invention is one comprising: toner particles comprising fine magnetic particles (A) and a binder resin; and fine magnetic particles (B) externally added to the toner particles, in which the maximum permeability (?mA) of the fine magnetic particles (A) contained in the toner particles and the maximum permeability (?mB) of the fine magnetic particles (B) externally added to the toner particles satisfy a relationship represented by the following formula (1) ?mB/?mA?1.8 .

Abstract: The present invention provides a one-component magnetic toner for developing an electrostatic charge image, which do not cause an image defect by toner aggregation or fusion even though a device is miniaturized and the processing speed of the device is accelerated, and which allows easy recycling of a toner cartridge. The one-component magnetic toner for developing an electrostatic charge image of the present invention is one comprising; toner particles comprising fine magnetic particles (A) and a binder resin; and fine magnetic particles (B) externally added to the toner particles, in which the maximum permeability (?mA) of the fine magnetic particles (A) contained in the toner particles and the maximum permeability (?mB) of the fine magnetic particles (B) externally added to the toner particles satisfy a relationship represented by the following formula (1). ?mB/?mA?1.

Abstract: Magnetic particles for charging means disposed in contact with an electrophotographic photosensitive member for charging the electrophotographic photosensitive member based on a voltage applied thereto are provided as particles of a ferrite component represented by the following formula (1): (Fe2O3)X(A)Y(B)Z  (1), wherein A denotes at least one metal oxide component selected from the group consisting of Li2O, MnO and MgO, B denotes at least one metal oxide component different from A; X, Y and Z denote numbers representing mol ratios and satisfying the following conditions: 0.2<X<0.95, 0.01<Y<0.5, X+Y≦1, and 0≦Z<0.79. The magnetic particles show an excellent charging performance, particularly in injection charging, without causing a difficulty, such as soiling or pinhole leakage of the photosensitive member.

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: An electrophotographic image forming method according to (I) a so-called simultaneous development and cleaning scheme or cleaner-less scheme is effectively operated by using a specific non-magnetic toner. (II) The non-magnetic toner comprises non-magnetic toner particles having a shape factor SF-1 of 120-160, a shape factor SF-2 of 115-140 and a weight-average particle size of 4-9 .mu.m. (III) The non-magnetic toner further includes inorganic fine particles (a) having a number-average primary particle size of at most 50 nm and spherical fine particles (b) having a number-average primary particle size of 50-1000 nm and a surface area-based sphericity .psi. of 0.91-1.00, respectively externally added to the non-magnetic toner particles.

Abstract: An electrophotographic apparatus is constituted by an electrophotographic photosensitive member, and a charger, imagewise exposing light and a developer disposed in this order opposite to the photosensitive member. The photosensitive member has a surface layer which is a charge-injection layer. The charger includes a charging member formed of magnetic particles and disposed contactable to the photosensitive member so as to charge the photosensitive member to at least 80% of a DC voltage supplied to the charging member. The magnetic particles have a volume resistivity in the range of 1.times.10.sup.4 -1.times.10.sup.9 ohm.cm, and the magnetic particles have a surface layer having a volume resistivity of at most 1.times.10.sup.9 ohm.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: An image forming method comprising;a charging step of electrostatically charging a photosensitive member;an exposure step of exposing the charged photosensitive member to form an electrostatic latent image;a developing step of bringing a toner carried on a developer carrying member, into contact with the surface of the photosensitive member to develop the electrostatic latent image to form a toner image on the photosensitive member;a transfer step of transferring the toner image formed on the photosensitive member, to a transfer medium; anda cleaning-at-development step of collecting the toner remaining on the photosensitive member after the transfer step, onto the developer carrying member;a wherein;the surface of said photosensitive member has a contact angle with water of 85.degree. or greater;said toner contains residual monomers in an amount not more than 1,000 ppm; andsaid toner has a shape factor SF-1 of from 100 to 180 and a shape factor SF-2 of from 100 to 140.

Abstract: An image forming apparatus includes an image bearing member; developing-cleaning member for cleaning the image bearing member by removing residual toner from the image bearing member simultaneously with formation of a toner image by developing an electrostatic latent image formed on the image bearing member with toner having a charging polarity opposite from a charge polarity of the electrostatic latent image; transfer member for transferring the toner image from the image bearing member to a transfer material; and charging member for charging the toner remaining on the image bearing member after image transfer by the transfer member and before development by the developing-cleaning member to a polarity which is the same as the charging polarity of the toner image, and for charging the image bearing member to a polarity which is opposite from the charging polarity of the toner image.

Abstract: An image forming method and image forming apparatus for charging a photosensitive member, exposing the charged photosensitive member thereby forming an electrostatic latent image, carrying toner with a toner carrying member to bring the toner into contact with the photosensitive member surface, thereby developing the electrostatic latent image and forming a toner image upon the photosensitive member, transferring the toner image that is on the photosensitive member to transfer material such as paper, and conducting a simultaneous developing-cleaning process which recovers residual toner remaining on the photosensitive member following the transfer process, so that toner consumption is greatly reduced and high image quality is maintained at the same time. The angle of contact of the photosensitive member surface to water is 85.degree.

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 method includes forming an electrostatic latent image on an image bearing member having a surface of which contact angle with water is at least 90.degree., forming a toner layer on a toner carrying member, bringing the toner layer into contact with the surface of the image bearing member on which the electrostatic latent image has been formed, while rotating the image bearing member and the toner carrying member reciprocally, and developing the electrostatic latent image by the use of the toner of the toner layer to form a toner image.

Abstract: A contact charging member is used in a charging device for charging an image carrier by contacting the contact charging member to which a voltage is impressed with the image carrier. The contact charging member has at least a supporting member and a coating member. The coating member is a seamless tube consisting of a resin blend of a flexible resin and a heat resistant resin.

Abstract: An electrophotographic image forming method including a toner image transfer step and eliminating an independent step for cleaning transfer residual toner is operated without causing ghost images and with good gradation and dot reproducibilities. In the method, the photosensitive member is exposed at an exposure intensity which is at least a minimum exposure intensity and below a maximum exposure intensity. The minimum exposure intensity is determined on a surface potential-exposure intensity characteristic curve of the photosensitive member by determining a first slope S1 of a straight line connecting a point giving a dark part potential Vd and a point giving a value of (Vd+ a residual potential Vr)/2, determining a contact point between a tangent line having a slope of S1/20 and the surface potential-exposure intensity characteristic curve and determining the minimum exposure intensity as an exposure intensity at the contact point.

Abstract: A toner for developing electrostatic latent images with a good combination of fixability, anti-offset characteristic, anti-sticking characteristic and pulverizability contains a composition comprising a colorant or magnetic material and a binder resin. The binder resin has 0.1 to 60 wt. % of a chloroform-insoluble or a THF (tetrahydrofuran)-insoluble component and a THF-soluble component, the THF-soluble providing a molecular weight distribution in the chromatogram of GPC (gel permeation chromatography) thereof such that there is a main peak in the molecular weight range of 1,000 to 25,000 and a sub-peak or shoulder in the molecular weight range of 2,000 to 150,000. The binder resin may suitably be obtained through two polymerization steps including a solution polymerization step and a suspension polymerization step.