Abstract: An electrophotographic photosensitive member is constituted by a support and a photosensitive layer disposed on the support. The electrophotographic photosensitive member has a surface layer comprising a polyester resin having a recurring unit represented by the following formula (1): wherein A1 represents a substituted or unsubstituted divalent aliphatic hydrocarbon group. The resultant surface layer is effective in improving an abrasive resistance of the photosensitive member.

Abstract: An image forming apparatus includes an image bearing member, a charging unit for charging the image bearing member, an image forming unit for forming an electrostatic image on the image bearing member charged by the charging unit, a developing device for developing the electrostatic image on the image bearing member and for supplying to the image bearing member charging performance enhancing particles which have a polarity opposite from that of the toner, wherein the developing device has a developer carrying member, opposed to the image bearing member, for carrying the toner and charging performance enhancing particles and also which forms an alternating electric field between the developer carrying member and the image bearing member to supply the toner and the charging performance enhancing particles to the image bearing member.

Abstract: An image forming apparatus having a roller-shaped charging brush includes a first member for raising the brush pile and cleaning it while rotating in contact with the roller-shaped charging brush and a second member located at a position following the first member in the rotation direction of the roller-shaped charging brush, for shaping the brush pile raised by the first member while contacting with the roller-shaped charging brush. A combination of the first and second members can provide a satisfactory charging function at all times.

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 material is molded in the shape of a roller and then the molded material is vulcanized to manufacture an elastic roller. The material consists of 100 parts by weight of EPDM polymer (E505 (trade name) manufactured by Sumitomo Kagaku Co., Ltd.), 10 parts by weight of silica which is used as filler (NipsilVN3 (trade name) manufactured by Nippon Silica Co., Ltd.), 30 parts by weight of paraffin oil (PW-909 (trade name) manufactured by Idemitsu Kosan Co., Ltd.), one part by weight of stearic acid, five parts by weight of zinc oxide, two parts by weight of sulfur (manufactured by Tsurumi Kagaku Co., Ltd.), one part by weight of vulcanizing accelerator (mercaptobenzothiazole and Noxceller-M (trade name) manufactured by Ouchishinko Kagaku Co., Ltd.), 0.5 parts by weight of vulcanizing accelerator (tetraethylthiuram disulfide and Noxceller-TET (trade name) manufactured by Ouchishinko Kagaku Co., Ltd.

Abstract: A charging device includes a charging member for being supplied with a voltage to electrically charge a rotatable member to be charged, the charging member including a magnetic particle layer contactable to the member to be charged, and a carrying member for carrying the magnetic particle layer; wherein the member to be charged starts to rotate after start of application of the voltage and after the start of rotation of the carrying member.

Abstract: In order to reduce the cost of a photosensitive member and to prevent the fluctuation in image density and the image smear by highly precise temperature control, the image forming apparatus of the present invention includes: a cylindrical photosensitive member with a conductive substrate having a thickness not smaller than 0.1 mm and smaller than 2.5 mm, and a light-receiving layer having a photoconductive layer on the conductive substrate, the light-receiving layer containing at least amorphous silicon; and a charging device for charging the photosensitive member, wherein the photoconductive layer has a thickness not smaller than 5 .mu.m and smaller than 20 .mu.m, and wherein the charging device is a device for contacting a charging member with the surface of the photosensitive member and applying a voltage to the charging member to charge the photosensitive member.

Abstract: A charging or image transfer unit for use in an image formation process including the steps of charging, image formation exposure, image development, image transfer, image fixing and cleaning, for applying an electric field to the surface of an electrophotographic photoconductor by coming into contact therewith, and also for controlling surface properties of the electrophotographic photo-conductor. The unit includes an electric field application member applying the electric field to the surface of the electrophotographic photoconductor and a lubricity-imparting member for controlling a friction coefficient of the surface of the electrophotographic photoconductor wherein the electric field application member includes an electrophotoconductive material and a lubricity-imparting member includes a fluoroplastic material.

Abstract: A charging device includes a charging member to which a voltage is applicable to charge 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 to provide a speed difference between a surface of the member to be charged and a surface of the flexible member; wherein not less than 10.sup.2 /mm.sup.2 electroconductive particles are provided in the nip.

Abstract: An image forming apparatus prevents the transfer, onto an intermediate transfer member, of the remaining toner after having passed under a cleaning blade by the small vibration phenomenon thereof induced by the shock resulting from the stopping or starting of the rotation of a photosensitive drum. At the start-up of the image forming apparatus or at the end of the printing operation, the intermediate transfer member is separated from the photosensitive drum. Then, after the start of the printing operation, the photosensitive drum is rotated while it is separated from the intermediate transfer member. Then the photosensitive drum is contacted with the intermediate transfer member after an abutting portion on the photosensitive drum, where the cleaning blade is in contact in the stopped state of the image forming apparatus, passes through a position opposed to the intermediate transfer member, and the image forming operation is then initiated.

Abstract: A biasable component having a fluorinated carbon filled polymer foam layer which exhibits controlled electrical conductivity and improved hardness is set forth.

Abstract: A charging apparatus for an electrophotographic apparatus has a charging member provided with a magnetic brush of magnetic particles and an object member to be charged. The charging member is capable of electrostatically charging the object member upon application of a voltage. The magnetic particles are composed of a composite containing 80 to 98% by weight of a metal oxide and a thermosetting resin having been carbonized in part. Magnetic particles having a particle diameter 1/2 times or less the number-average particle diameter of the particles are contained in an amount of 30% or less by number.

Abstract: A charging apparatus for charging a member to be charged includes an elastic member, the elastic member being press-contacted to a surface of the member to be charged, and electroconductive particles carried on the surface of the elastic member to which a charging voltage is applied, wherein a triboelectric charging property of the member to be charged relative to the elastic member is the same as a charging polarity of the charging apparatus.

Abstract: A charging device includes a charging member to which a voltage is applicable to charge a member to be charged; an electroconductive particle supply member for supplying electroconductive particles, wherein the supply member produces the electroconductive particles by abrasion of itself, and the thus produced electroconductive particles are fed to the nip formed by the charging member and the member to be charged.

Abstract: A charging roller for use in a machine in which an electrical bias is applied to a surface of a member is provided. The charging roller includes a shaft, a foam material surrounding at least a portion of the shaft, and a thermoplastic material. The thermoplastic material surrounds at least a portion of the foam material. The foam material is adapted to provide for greater compliance to prevent vibration of the roller against the surface.

Abstract: Improvement has been made in an image forming method comprising charging electrically an image holding member, forming a latent electrostatic image on the image holding member, developing the latent image with a toner, transferring the toner image onto a toner image receiving medium, and recovering untransferred toner. In this method, a magnetic brush formed from magnetic particles electrifies the image holding member by contact with the image holding member surface, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member, wherein the toner has a weight-average particle diameter of not larger than 1/3 of average particle diameter of the magnetic particles and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 50% by volume.

Abstract: An image forming apparatus includes a rotatable image bearing member and a contact-charging member which contacts a surface of the image bearing member. The contact-charging member can charge the image bearing member by applying a predetermined voltage to the contact-charging member so that a potential of the contact-charging member is changed to a required potential for transferring a residual toner that is stuck on a surface of the contact-charging member facing the image bearing member onto the image bearing member while the image bearing member stops rotating. A method for removing residual toner sticking onto a contact-charging member that contacts a surface of the image bearing member changes a potential of the contact charging member to a required cleaning potential for transferring the residual toner sticking to a surface of the contact-charging member facing the image bearing member onto the contact-charging member while the image bearing member stops rotating.

Abstract: An electrophotographic printing apparatus has two charging bodies that are held at different potentials. The first charging body makes contact with the surface of a photosensitive drum; the second charging body makes contact with the first charging body. Toner particles that have acquired an electrostatic charge opposite to their normal charge are attracted from the drum surface to the first charging body. These toner particles are then attracted from the first charging body to the second charging body, whereby the first charging body is kept clean and able to charge the surface of the photosensitive drum to a uniform potential.

Abstract: A method of cleaning is used to remove residual toner in an electrophotographic printer. After a printing operation, some amount of normally-charged toner and reversely-charged toner is left on the photoconductive drum and rollers such as charging rollers, transfer roller, and cleaning roller in contact with the photoconductive drum. A potential difference is applied between two members, for example, the cleaning roller and the photoconductive drum in electrical contact with each other so as to cause the residual toner to migrate from one member to the other. The potential differences are applied at specific timings so that the residual toner migrates properly onto the rotating photoconductive drum and is carried to the developing section for reuse.

Abstract: An electrophotographic apparatus which simultaneously performs image exposure and development, including an electrophotographic photosensitive body having a conductive layer, an electrophotoconductive layer, and an electric charge supply layer for contacting a developer sequentially formed on a translucent substrate, wherein a value of the surface energy of the outer layer of the photosensitive body is 30 dyne/cm or less in order to present fogging generated during development.

Abstract: An image forming apparatus includes: a photosensitive unit having a surface portion of negatively charging property and moved in a predetermined direction; a first charging device disposed opposite to the photosensitive unit with a first spacing therebetween and for charging the surface of the photosensitive unit to a first charged potential of negative polarity by a negative voltage; a second charging device disposed opposite to the photosensitive unit with a second spacing therebetween at a position downstream of the first charging device in a movement direction of the photosensitive unit and for charging the surface of the photosensitive unit charged by the first charging device to a second charged potential of negative polarity by a positive voltage, the second charged potential having an absolute value smaller than an absolute value of the first charged potential; an electrostatic latent image forming device for forming an electrostatic latent image on the photosensitive unit; and a developer carrying de

Abstract: A granular charging agent capable of injecting the electric charge into a material to charge the surface of the material when coming in contact with the material with the application of a voltage to the charging agent, comprising magnetic particles which comprise electroconductive magnetic particles and high-resistivity magnetic particles of which resistivity is higher than that of the electroconductive magnetic particles. A granular charging agent may comprise magnetic particles, each magnetic particle comprising an electroconductive surface portion capable of forming a flow path of electric current and a surface portion with a resistivity higher than that of the electroconductive surface portion. In addition, a method of charging a material such as a photoconductor using the above-mentioned granular charging agent is disclosed.

Abstract: A charging device which includes a sheet-like charging member to be brought into contact with a charge target member. The charging member being composed of at least an insulating layer and a resistance layer. The charging device further includes at least one voltage application device which applies a DC voltage to the resistance layer of the charging member. The resistance layer has a down stream portion which protrudes from the insulating layer, which is arranged at the side of the resistance layer of the charge target member. The down stream portion may take on various shapes which uniformly apply a charge to the charge target member. The charging member may further include another resistive layer which has a second voltage applied thereto, wherein the other resistive layer is mounted on the other side of the insulating layer and contacts the charge target member and securely holds the charging member in contact with the charge target member.

Abstract: An image forming apparatus with a charging member that allows easy removal of smears from an image forming drum. The apparatus removes smears from the image forming drum by placing a different portion of the charging member in contact with the drum. The apparatus uses a cam or a solenoid to press on the charging member to cause a different portion of the charging member to come into contact with the image forming drum.

Abstract: An image forming apparatus includes an image bearing member; a charging member, contactable to the image bearing member, for being supplied with a voltage to electrically charge the image bearing member, the charging member having a resistance which is larger when it is supplied with a voltage of 50V than when it is supplied with a voltage of 500V; developing device for developing with toner an electrostatic image formed on the image bearing member using charging operation of the charging member, the developing means being capable of removing the toner from the image bearing member; wherein the voltage is an oscillating voltage, and a ratio T.sub.up of time period when a voltage level thereof is in a side of a charging polarity of the charging member beyond an average voltage in one period of the oscillating voltage to a length of time of one period of the oscillating voltage, and a ratio T.sub.

Abstract: A charging apparatus is disclosed which has an object member and a charging member. The charging member has magnetic particles, provided in contact with the object member and capable of electrostatically charging the object member upon application of a voltage. The surfaces of the magnetic particles are formed of a composite which includes conductive particles and a binder resin, and the conductive particles are in a proportion of from 80% by weight to 99% by weight in total weight based on the weight of the composite. The conductive particles have a size distribution having at least two peaks or shoulders. Also, an electrophotographic apparatus having the charging member is disclosed.

Abstract: Applied voltage to the contact charging sheet 71 has been controlled in the following various ways: a) the voltage at the photosensitive layer 10 at a point of time whereat it has passed the contact charging sheet 71 is caused to interlock with grid voltage so as not to exceed predetermined voltage to be electrified by the Scorotron charger 2; b) the applied voltage is caused to interlock with the output from the transfer unit 5 so that there is no portion which reaches the Scorotron charger 2 while the potential polarity has been reversed at the transfer unit 5; c) reduction in the film thickness of the photosensitive layer 10 is corrected in consideration of the cumulative number of sheets for image formation; d) the size of printing sheet is added; e) at the time of termination, a portion of the photosensitive layer 10, into which current has flowed at the transfer unit 5, is caused to stop always after passing the contact charging sheet 71; f) the contact charging sheet 71 is cleaned by means of AC compon

Abstract: An apparatus and method that insures an even distribution of liquid in an aquatron charging device across the entire length of the device. This enables uniform charging across the width of the photoreceptor. The present invention fills and pressurizes a porous tube with a liquid. The liquid evenly exudes from the pores along the entire length of the porous tube. A hydrophilic liquid retentive foam which contacts the photoreceptor surface is wrapped snugly around the tube. The conductivity and overall rate of dispensation of liquid is controlled by the pressure differential across the porous tube.

Abstract: An electrostatographic printing machine and apparatus that utilizes a two layer roll charger for contact charging of photoreceptors. The charger includes a liquid retentive foam layer fitted over an electrically conductive shaft. The shaft can be solid or porous, the later requiring a separate liquid reservoir. The second layer is a thin liquid permeable member, over the foam layer, which transmits water at a slow, but controlled rate during the rotation of the roller. The roller may rotate synchronously with the photoreceptor or be allowed to slip on the photoreceptor surface to improve uniformity and contact. The membrane increases life by controlling the runout of liquid from the repository. Also, the present invention permits charging over photoreceptor pinholes.

Abstract: An image forming apparatus includes a charging device applies a voltage to charge an image bearing member. The charging device is provided with a charging means to which a voltage is applicable to charge said image bearing member, said charging means being provided with a magnetic particle carrying member for carrying and conveying a magnetic particle layer contacting with said image bearing member during the charging operation; a container contains magnetic particles therein; and a replacing device replaces the magnetic particles carried on the magnetic particle carrying member with the magnetic particles contained in the container. A developer develops a latent image produced on the image bearing member by the charging device using a toner to produce a toner image.

Abstract: An electrostatographic printing machine and apparatus that utilizes a foam roll aquatron with a hydrophilic web between it and the photoreceptor. The porous web captures and removes toner particles which ordinarily would be trapped in the foam roll nip and cause image quality defects, such as streaking.

Abstract: A contact charging device, in which a contact member for charging has a surface including a contact portion to be in contact with a charge receiving member as well as a charge contributing portion having a surface resistivity (.rho.s) of 1.times.10.sup.5 .OMEGA./.quadrature. or less. A maximum distance between the contributing portion and the charge receiving member is in a range from 5 .mu.m to 60 .mu.m. Alternatively, an electric power formed of a DC component is applied to the contact member to produce a potential difference in a range from 550 v to 750 v between the applied power and a potential at the surface of the charge receiving member before being charged by the electric power.

Abstract: A charging member is disposed so as to contact a surface of a charge-receiving member which moves relative to the charging member. In conjunction with the movement of the charge receiving member, the charging member removes foreign substance present on the charge-receiving member on the upstream side in the direction of travel of the charge-receiving member at the contact region with the charging member. Simultaneously, a discharge voltage is applied to the charging member so that the charging member charges the charge-receiving member in the area from which said foreign substance has been removed at the contact region on the downstream side of the charge-receiving member in the direction of travel of the charge-receiving member. During a cleaning operation, the charging member retracts from the charge-receiving member and is out of contact therewith in accordance with the number of image formations, black and white ratio, and humidity.

Abstract: A charging apparatus for a photoconductor composed of an electroconductive charging member and mechanism for feeding a voltage to the charging member. This charging apparatus is composed of a material capable of adsorbing ozone. The charging apparatus may be in the form of a roller type, a blade type or the like. Carbon fibers having micro pores can be used as the charging member.

Abstract: The present invention provides a contact charging device, in which a contact member for charging is in contact with a charge receiving member for charging the same while suppressing charging irregularity. The contact member has a surface to be in contact with the charge receiving member. This surface has a volume resistivity in a range from 1.times.10.sup.4 .OMEGA..multidot.cm to 1.times.10.sup.10 .OMEGA..multidot.cm, and has a surface resistivity in a range from 1.times.10.sup.5 .OMEGA./.quadrature. to 1.times.10.sup.10 .OMEGA./.quadrature..Alternatively, the contact member has a surface to be in contact with the charge receiving member. This surface of the contact member has a surface hardness which provides a scratch width of 1 .mu.m or less under scratch hardness test.

Abstract: A charging device K is provided with a flexible electrode 12 and a flexible intermediate member M disposed between the flexible electrode 12 and a charge-receiving member 10, with the flexible intermediate member M being in contact with the charge-receiving member 10. The flexible intermediate member M includes a flexible insulated member 11 and semiconductive member 14 so as to charge the charge-receiving member 10 via a discharge from electrode 12. The absolute value of the difference between the potential of the flexible electrode 12 during discharge and the potential in the vicinity of at least the area of discharge of the flexible electrode 12 among areas in which the flexible intermediate member is in contact with the charge-receiving member 10, is less than the absolute value of the difference between the potential of the charge-receiving member and the potential of the flexible electrode during discharge.

Abstract: A charging method in which the surface of an image bearing device is charged in two steps in contact with the surface of the image bearing device before a latent image is formed on the surface of the image bearing device, the contact charging method includes two steps. First, the surface of the image bearing device is charged with a contact charging device which applies a voltage consisting of an AC component and a DC component superposed on the AC component. Second, the surface of the image bearing device is charged by a contact charging device applied with such a DC voltage as to discharge at least part of a pattern of charge potential variation of which the pitch corresponds to the frequency pitch of the AC component, which is caused in the primary charging operation.

Abstract: A method of controlling a charge voltage of an image forming apparatus using an electrophotographic developing process so as to enhance cleaning efficiency by increasing the number of collecting positively-charged toner adhering to contact charging unit. The method includes: applying a charge voltage of a predetermined voltage level to a contact charging unit to uniformly charge an outer surface of a photoconductive body to a predetermined polarity while a main motor rotates; when cleaning the contact charging unit, applying a charge voltage exhibiting a voltage level lower than the predetermined voltage level to the contact charging unit to create a potential difference between the contact charging unit the photoconductive body; and transferring charged toner particles adhered to the contact charging unit, to the photoconductive body by shutting off the charge voltage being applied to the contact charging unit.

Abstract: The present invention describes a charging device pressed against the surface of a body to be charged in a state of being applied with a voltage so as to charge the body. The charging device includes an electrically conductive support to which a voltage is to be applied; an electrically conductive elastic body layer fixed on the electrically conductive support; a resistance regulation layer covering the electrically conductive elastic body layer; and a protective layer laminated on the resistance regulation layer, having hardness of 6 H or more in pencil hardness, and made from a silicon compound.

Abstract: An image forming apparatus includes image bearing member for bearing a toner image; charging member contactable to the image bearing member to electrically charge the image bearing member; wherein .delta.V=.vertline.Vdc-Vs.vertline. is different between a first area of the image bearing member which is going to be image area and second area of the image bearing member which is going to be non-image area, where Vdc is a DC component of a voltage applied to the charging member, and Vs is is a potential of the image bearing member charged by the charging member.

Abstract: An apparatus, printing machine and method for replenishing an aquatron liquid reservoir in an aquatron charging device. The print media (e.g. paper, vellum, etc.) releases liquid from the print media during fusing. A condenser creates condensate from the liquid released by the print media which is collected in a conduit and transported using air flow into a collection container. This collection container can be the aquatron liquid reservoir, or a separate collection container that pumps liquid to the aquatron liquid reservoir, thus, enabling replenishing the liquid supply of the aquatron liquid reservoir within the printing machine. Sensing devices measuring liquid concentration resistance in the aquatron liquid reservoir and/or the collection container control the liquid level of the reservoir and/or collection container.

Abstract: An device for applying an electrical charge to a member to be charged such as a charge retentive surface in an electrostatographic printing apparatus, including a multi-contact point conductive charging device positioned in contact with the member to be charged. The charging device includes multiple electrically isolated conductive blades which are independently electrically biased at predetermined voltage levels so as not to exceed a Paschen threshold voltage differential. Alternative embodiments are disclosed incorporating conductive blade members, as well as ionically conductive liquid carrying donor members. In operation, the charging device of the present invention permits generation of a charge potential on the photoreceptor significantly greater than the Paschen threshold voltage, while avoiding air breakdown.

Abstract: A charging device which is pressed against a surface of a body to be charged in a state that a voltage is applied to charge the body, having an electrically conductive support to which a voltage is applied; an electrically conductive elastic body layer fixed on the electrically conductive support for dispersing electrically conductive particles to regulate resistance and hardness; an electrode layer provided on the electrically conductive elastic body layer, and having an electrically conductive inorganic material; and a resistance regulation layer provided on the electrode layer for regulating resistance.

Abstract: A contact charging device includes: a member to be charged rotatably provided; a conductive member having a soft endless thin film shape, for charging or discharging the member to be charged such that the conductive member is electrostatically attracted to the member to be charged as the member rotates; and a supporting member, disposed apart from the member to be charged, for holding the conductive member while resisting the electrostatic attracting force such that the conductive member is stretched, to allow the conductive member to rotate together with the member to be charged.

Abstract: An apparatus and method that utilize a sensor circuit and a liquid supply to control resistance of a fluid carrier of an aquatron. The resistance of the fluid carrier or charging pad is maintained by controlling the loading or concentration of liquid in the charging pad. A comparison of the fluid or liquid level in the charging pad to the desired fluid level for the charging pad triggers the addition or reduction of fluid to the charging pad to achieve the desired fluid level and thus the desired resistance. A minimum fluid carrier resistance is required to prevent loading the power supply when charging over pinholes and scratches in the imaging surface.

Abstract: A negative-electrification type electrophotographic photoreceptor which has an undercoat layer slightly soluble or insoluble in solvents and retains stable properties, and to provide a contact electrification type electrophotographic apparatus employing the photoreceptor and less apt to suffer dielectric breakdown. The electrophotographic photoreceptor comprises an electrically conductive support having thereon an undercoat layer and a photosensitive layer, in which the undercoat layer comprises an electron-transporting pigment and a reactive organometallic compound. This electrophotographic photoreceptor is suitable for use in an electrophotographic apparatus in which the photoreceptor is charged by applying a voltage to a charging member disposed so as to be in contact with the photoreceptor, in particular, an erase-less electrophotographic apparatus.

Abstract: An image forming apparatus includes: an image bearing member including a surface layer having a volume resistivity which changes with intensity of the electric field; an image forming device for forming, on the image bearing member, an electrostatic image having a portion of dark potential VD (V) and a portion of light potential VL (V) with a resolution of A (dot/micron) the image forming means including a charging member contactable to the image bearing member to charge the image bearing member by applying a voltage of the charging member; wherein the volume resistivity RDL (Ohm.cm) of the surface layer under the electric field of .vertline.VD-VL.vertline..times.A, if larger than 1.0.times.10.sup.11 (Ohm.cm), and is not less than twice as large as RD which is a volume resistivity of the surface layer (Ohm.cm) under the electric field of VD.times.A, and the volume resistivity RD is smaller than 2.0.times.10.sup.13.

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 device of an electrophotography printing apparatus may improved the charging efficiency by preventing the potential difference generated at both ends of a photosensitive drum. An auxiliary charging device includes an auxiliary charging plate to which voltage is applied. The plate is installed to come into contact with both ends of the photosensitive drum in order to compensate for a potential level in a developing cartridge. The electrophotography printing apparatus may include a charging unit, a developing unit and a toner supplying unit provided around the photosensitive drum.

Abstract: A charging apparatus includes a charging member contactable or proximatable to a member to be charged, the charging member being capable of being supplied with a voltage; wherein the charging member has a magnetic particle layer, and a magnetic force generator with a gap for generating magnetic force in the magnetic particles, the magnetic particle layer and magnetic force generator forming a magnetic circuit; and wherein the magnetic particle has a particle size of no less than 10 .mu.m and no more than 100 .mu.m, and the maximum magnetic flux density in the gap ranges 1,000.times.10.sup.-4 T-10,000.times.10.sup.-4 T.