Abstract: An image forming apparatus includes an image bearing member; charging means for electrically charging the image bearing member; a rotatable developer carrying member for carrying a developer to develop an electrostatic image formed on the image bearing member with the developer, the developer carrying member being supplied with a developing bias voltage comprising an AC voltage; non-rotatable magnetic field generating means, disposed inside the developer carrying member, for magnetically attracting the developer on the developer carrying member, wherein the developer carrying member has a surface elastic layer, and the developer carrying member is press-contacted to the image bearing member, and the developer is one component magnetic toner, and a maximum value of an absolute value of the developing bias voltage |V| max (V) and a surface potential of the image bearing member charge by the charging means is Vd global purposes V), satisfy, |V|max?|Vd|.

Abstract: A developing device includes a rotatable developer carrying member for carrying a developer to develop an electrostatic image formed on an image bearing member with the developer; non-rotatable magnetic field generating means, disposed inside the developer carrying member, for magnetically attracting the developer on the developer carrying member; a regulating member for regulating an amount of the developer carried on the developer carrying member, wherein the developer carrying member is provided with a surface elastic layer, and the developer carrying member is press-contacted to the image bearing member, and wherein, the developer is an one component magnetic toner having an average circularity not less than 0.965, and an amount of the developer per unit area of the developer regulated by the regulating member is 5-14 g/m2, and an amount of electric charge thereof is 10-50 ?C/g.

Abstract: A charging member for charging a member to be charged, includes an elastic foam member provided at a surface of the charging member. The elastic foam member includes a plurality of cell portions with wall portion defining the cell portions. The gaps connecting the cell portions have areas which are not less than 5% and not more than 50%, for respective cells.

Abstract: A charging member for charging a member to be charged and an image forming apparatus provided with the same have electrically conductive particles and an electrically conductive particle bearing member having elasticity and bearing the electrically conductive particles thereon, and the degree of cohesion of the electrically conductive particles is 0.1 to 85%. Thereby, the non-uniformity of a halftone image peculiar to particle charging can be improved.

Abstract: A charging apparatus includes a charging member for charging a member to be charged while forming a nip with the member to be charged, and electroconductive particles disposed in the nip. The charging member is supplied with a voltage of a certain polarity, a surface of the member to be charged is triboelectrically charged by a surface of the charging member so as to have a polarity opposite from that of the voltage, and the electroconductive particles are triboelectrically charged in the nip so as to have a polarity opposite from that of the voltage.

Abstract: An image-forming apparatus includes a pre-charge exposure device which removes electric charge from a photoconductor drum to increase a potential contrast between the surface of the photoconductor drum and the surface of a charge roller in an upstream region of a nip region between the photoconductor drum and the charge roller in the rotating direction of the photoconductor drum, so that toner accumulating in an upstream region of the nip region in the rotating direction of the photoconductor drum is restrained and prevented from being discharged onto an image-forming region. When the toner accumulating in the upstream region of the nip region in the rotating direction of the photoconductor drum is to be discharged onto a non-image-forming region, the pre-charge exposure device is turned off so that the potential contrast decreases.

Abstract: A charging device includes a charging member for electrically charging a member to be charged which is adapted to form a nip with a member to be charged which has a surface layer having a volume resistivity of 1×109-1×1014 &OHgr;cm, said charging member having an elastic member and movable with a peripheral speed difference relative to the member to be charged; and electroconductive particles carried on said charging member to the nip, wherein a peripheral speed Vd (mm/sec) of said member to be charged, a peripheral speed Vc (mm/sec) of said charging member, a width N (mm) of the nip measured in a moving direction of said charging member, and a coverage ratio Rc of said electroconductive particles on said charging member, satisfy: N·Rc·|Vc−Vd|/Vd≧1.

Abstract: An image forming apparatus includes an image bearing member; a charging member for electrically charging the image bearing member; developing means for developing with a developer an electrostatic latent image formed on the image bearing member, the developing means having a developer carrying member for carrying the developer, wherein a gap is formed between the developer carrying member and the image bearing member; bias voltage applying means for applying a bias voltage to the developer carrying member, wherein the bias applying means applies an AC bias when the electrostatic latent image is developed, wherein the developing means is capable of collecting the developer fro the image bearing member, and an amplitude of an AC bias voltage applied to the developer carrying member by the bias applying means when the the developer is collected, is larger than that when the the electrostatic latent image is developed.

Abstract: A charging member for charging a member to be charged and an image forming apparatus provided with the same have electrically conductive particles and an electrically conductive particle bearing member having elasticity and bearing the electrically conductive particles thereon, and the degree of cohesion of the electrically conductive particles is 0.1 to 85%. Thereby, the non-uniformity of a halftone image peculiar to particle charging can be improved.

Abstract: A charging apparatus includes a charging member for charging a member to be charged while forming a nip with the member to be charged, and electroconductive particles disposed in the nip. The charging member is supplied with a voltage of a polarity, a surface of the member to be charged is triboelectrically charged by a surface of the charging member so as to have a polarity opposite from that of the voltage, and the electroconductive particles are triboelectrically charged in the nip so as to have a polarity opposite from that of the voltage.

Abstract: An electrifier for electrifying a member to be charged includes a charge rotary member that forms a first nip with the member to be charged, to charge the member to be charged, and that holds and carries charge particles to the first nip, and a nip forming member that forms a second nip with the charge rotary member, the nip forming member having a bias charge having the same polarity as the developer.

Abstract: A charging apparatus includes a charging member, to which a voltage is applicable, for charging a member to be charged; the charging member including: a flexible member for forming a nip with the member to be charged, wherein the flexible member is moved with a peripheral speed difference between surfaces of the flexible member and the member to be charged at the nip; and electroconductive particles in the nip.

Abstract: A charging device, suitable for use in an electrophotographic image forming apparatus, is formed of an object to be charged, and a roller-shaped charging member disposed in contact with the object via electroconductive particles and supplied with a voltage to charge the objects. The charging member has a surface layer including an elastic foam and is moved with a surface speed difference relative to the object. The charging member has surface cavities having an average diameter of 5 to 150 &mgr;m and occupying an area percentage of 50 to 90%. An image forming apparatus and a process cartridge therefor including the charging device are also provided.

Abstract: A charging device for electrically charging a member to be charged includes charging particles including electroconductive particles having particles diameters in the range of 10 nm-10 &mgr;m; and a charging particles carrying member, which has a nip with the member to be charged forming a nip with said member to be charged, for carrying the charging particle to the nip; wherein said charging particles have resistances in the range of 10−1-1012 &OHgr;cm; wherein (an amount, per unit area, of said charging particles carried by said charging particles carrying member)/(an average roughness Ra of a surface of said charging particles carrying member) is in the range of 0.005-1 mg/cm2/&mgr;m.

Abstract: An image forming apparatus includes an image bearing member; charging means for electrically charging the image bearing member, the charging means carrying electroconductive particles and having a charging member elastially press-contacted to the image bearing member; image forming means for forming an electrostatic image by selectively dissipating electric charge on the image bearing member charged by the charging means; developing means for developing the electrostatic image on the image bearing member with toner and for supplying the electroconductive particles to the image bearing member, wherein the electroconductive particles supplied by the developing means is carried to a press-contact portion of the charging member to contribution for electric charging of the image bearing member; and changing means for changing a relation between the charging member and a supply position of the electroconductive particles of the developing means.

Abstract: A charging device includes a charging member for electrically charging a member to be charged which is adapted to form a nip with a member to be charged which has a surface layer having a volume resistivity of 1×109-1×1014 &OHgr;cm, said charging member having an elastic member and movable with a peripheral speed difference relative to the member to be charged; and electroconductive particles carried on said charging member to the nip, wherein a peripheral speed Vd (mm/sec) of said member to be charged, a peripheral speed Vc (mm/sec) of said charging member, a width N (mm) of the nip measured in a moving direction of said charging member, and a coverage ratio Rc of said electroconductive particles on said charging member, satisfy: N·Rc·|Vc−Vd|/Vd≧1.

Abstract: A charging member for charging a member to be charged, includes an elastic foam member provided at a surface of the charging member, the elastic with wall portion defining the cell portions, wherein gaps connecting said cell portions have areas which are not less than 5% and not more than 50%, for respective cells.

Abstract: A charging apparatus includes a charging member for being supplied with a voltage to charge a member to be charged, the charging member including an elastic member for forming a nip with the member to be charged, and said elastic member having a surface provided with a plurality of projections; wherein a speed A of a surface of said charging member (mm/sec) and a speed B of a surface of the member to be charged (mm/sec) satisfy: when B−A>0, said projections are inclined toward upstream with respect to a movement direction of the surface of the member to be charged in said nip, and when B−A<0, the projections are inclined toward downstream with respect to a movement direction of the surface of the member to be charged in said nip.

Abstract: A developing apparatus prevents a reduction in image density due to paper powder by providing a developing apparatus that has a developing container, a toner carrying member, and a toner container, wherein the toner container has a space portion, which is disposed below the toner carrying member and which is not substantially replenished with the toner.

Abstract: An image-forming apparatus and an image-forming method using a cleanerless system are disclosed in which a non-contact developing assembly develops an electrostatic latent image with a magnetic one-component developer to form a magnetic-toner image and collects a magnetic toner having remained on the charging object member, a member to be charged is charged by means of a charging assembly having a charging member the surface of which is movable with a velocity differential in the opposite direction with respect to the surface of the charging object member, and conductive particles are present at least at the contact surfaces between the charging member and the charging object member.