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: A brush type charger capable of reducing noise which occurs on superposing AC voltage on DC voltage and of restraining image defects such as moire images and density unevenness from occurring will be supplied.In a brush type charger, having a shaft 1A for brush made of a conductive member, and a brush-shaped charging member 1B which is radially provided toward the outside around the shaft 1A for brush, and which is made of a conductive member entirely formed into a roller shape, configured such that the outer circumference of the brush-shaped charging member 1B is brought into contact with a photoreceptor 3 and predetermined DC voltage having AC voltage superimposed thereon is applied to the brush-shaped charging member 1B to thereby charge the photoreceptor 3, the brush-shaped charging member 1B is provided in a helical fashion around the shaft 1A for brush.

Abstract: An image forming apparatus includes an image bearing member for bearing an image. A charging device is supplied with a voltage. The charging device includes a magnetic brush contactable to the image bearing member to electrically charge the image bearing member. A developing device develops, at a developing position, an electrostatic image formed on the image bearing member using a charging operation of the charging device, with toner having the same polarity as a charging polarity of the charging device, into a toner image. The developing device is capable of removing residual toner from the image bearing member. The developing device stops its developing operation if an area of the image bearing member, which has been charged by the charging device when the charging device is being supplied with an oscillating voltage in the form of superimposed AC and DC voltages, is still at the developing position.

Abstract: A charging member supporting magnetic particles for charging a member to be charged, including: an electroconductive member to which a voltage is applicable; and a member electrically insulated from the electroconductive member at an end portion, in a longitudinal direction of the charging member, of the magnetic particles, wherein deposition of magnetic particles to the member to be charged from the charging member is effectively prevented.

Abstract: An image forming apparatus includes an image bearing member and a charging unit having magnetic particles that are contactable with the image bearing member. An electrostatic image forming unit forms an electrostatic image on the charged image bearing member. A developing device develops an electrostatic image on the image bearing member with toner that includes toner and magnetic carrier. A detecting unit detects the toner content of the developer and a toner supply unit supplies the toner into the developing unit when the detected toner content is lower than a predetermined level. A calculating unit calculates the changing rate of the toner content from an output of the detecting unit and a warning unit warns that a changing rate of the toner content is larger than a predetermined level.

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 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 which has a surface layer having a volume resistivity of 1.times.10.sup.9 -1.times.10.sup.14 .OMEGA.cm; a charging member contactable to the member to be charged to electrically charge the member to be charged, the charging member being supplied with a voltage having an AC voltage component; wherein e time constant .tau. (sec) of the member to be charged and the charging member, a frequency f (Hz) of the AC voltage component, and an effective voltage V.sub.AC (V) of the AC voltage component, satisfy :2V.sub.AC {1-exp(-1/2f/.tau.)}/{1+exp(-1/2f/.tau.)}.ltoreq.50.

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: An image forming apparatus includes an image bearing member; a charger for charging the image bearing member, the charger including a magnetic brush including magnetic particles contacted to the image bearing member; a developing device for developing an electrostatic image on the image bearing member, wherein the developing device includes a developer carrying member which is press-contacted to the image bearing member, and is movable in a direction opposite from a movement direction of the image bearing member at a portion where they are press-contacted to each other.

Abstract: An image forming apparatus includes a movable image bearing member; an electrostatic image forming device for forming an electrostatic image on the image bearing member, the electrostatic image forming device including a charging member, contactable to the image bearing member, for charging the image bearing member; developing device for developing the electrostatic image with toner to form a toner image on the image bearing member; a transfer device for transferring the toner image onto the transfer material from the image bearing member, wherein the developing device is capable of cleaning the image bearing member to remove residual toner from the image bearing member, without provision of cleaning device for removing the residual toner from the image bearing member at a position upstream of the charging member and downstream of the transfer device with respect to a moving direction of the image bearing member; and a charge application device, provided upstream of the charging member and downstream of the t

Abstract: An electrostatic imaging device has a photoreceptor drum, an exposure unit to form a latent image on the photoreceptor, a developing unit for forming a toner pattern on the photoreceptor, a transcribing roller for electrifying the photoreceptor drum and transcribing the toner pattern onto a recording sheet, a brush charger for electrifying the photoreceptor drum, and a power supply section for applying a first negative voltage to the transcribing roller and a second negative voltage to the brush charger during a period other than an image forming period. The second voltage is lower than the first voltage in absolute value. Undesirable particles having a positive potential and attached to the brush charger is collected to the photoreceptor drum for cleaning the brush charger.

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 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 image forming apparatus includes an image bearing member, latent image forming device for forming an electrostatic image on the image bearing member, the latent image forming device having a charging member contactable to the image bearing member to electrically charge the image bearing member, and the charging member being supplied with a voltage which includes an oscillation component, a developing device for developing the electrostatic latent image with toner into a toner image, the developing device being capable of removing residual toner from the image bearing member, a transfer device for transferring the toner image from the image bearing member onto a transfer material, and a frequency control device for controlling a frequency of the oscillation component so that the frequency is higher when at least a part of such an area of the image bearing member as is going to be a non-image area is charged than when such an area of the image bearing member as is going to be an image area is charged.

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: 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 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: An image forming apparatus includes an image bearing member; charging means for charging the image bearing member, the charging means including magnetic field generating means and magnetic particles contactable to the image bearing member at a charging position; developing means for developing with toner a electrostatic image formed on the image bearing member using the charging means; transferring means for transferring a toner image from the image bearing member onto a recording material; wherein the developing means is capable of collecting residual toner from the image bearing member; wherein magnetic confining force acting on the magnetic particle is larger than a magnetic confining force acting on the carrier under a magnetic field formed by the magnetic field generating means at the charging position.

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: An electronic printing device is disclosed which uses flexible whiskers to transfer a charge corresponding to an image to a dielectric recording surface. The recording surface preferably has areas of differing conductivity so that microfields form on the dielectric surface. Ink, preferably non-charged, may then be attracted to the recording surface through dipole forces and later transferred to paper.

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 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.

Abstract: An image-forming apparatus is provided which has a photosensitive member having improved temperature characteristics and improved electric properties and an ozoneless charging system in combination, and employs neither a heater nor a cleaning roller. In the apparatus, a charging member having a cylindrical multipolar magnetic body of 500 G or stronger and a magnetic brush layer formed from a magnetic powder on the peripheral surface of the magnetic body is allowed to rub the surface of a charging object in a reverse direction at a movement speed ratio of not less than 110% to charge the charging object. The charging object is a photosensitive member having a photoconductive layer composed of non-single-crystal silicon. The photoconductive layer contains hydrogen at a content ranging from 10 to 30 atomic %, and Si--H.sub.2 /Si--H at a ratio ranging from 0.2 to 0.5, having density of state ranging from 1.times.10.sup.14 cm.sup.-3 to 1.times.10.sup.16 cm.sup.

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: In a charging device used in a cleanerless image forming apparatus and including a charging brush in contact with an image bearing member, a scraping member is provided which is in contact with the charging brush with a predetermined amount of indentation overlap on an upstream side of a contact portion between the charging brush and the image bearing member with respect to a rotational direction of the charging brush. With such an arrangement, the developer, which is scraped from the charging brush by the scraping member and then adheres onto the image bearing member, is recharged by the charging brush so as to be collected by a developing-cleaning device.

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: This invention relates to a charging system for charging a body to be electrified, comprising a body to be electrified, and a charging member which can be applied with voltage to brush the surface of said body to be electrified and charge it. Wherein the surface of the body to be electrified exhibits a contact angle of 90.degree. or more for water.

Abstract: In an image forming apparatus, when a transferred material exists in a transfer position between a photoreceptor drum and a transfer unit during an image forming operation, a transfer voltage, which has opposite polarity to that of a voltage applied to a brush charger and is used for transferring a developer image on the photoreceptor drum onto the transferred material is applied to the transfer unit. Meanwhile, when a transferred material does not exist in the transfer position during the image forming operation, a non-transfer voltage, which is lower than the transfer voltage, is applied to the transfer unit. As a result, defects on an image due to returning of a developer from the brush charger to the photoreceptor drum can be prevented from being generated.

Abstract: An image forming apparatus includes a charging rotary brush in contact with a photosensitive member, a laser beam irradiator to form an electrostatic latent image, a developing unit for developing the latent image into a visible image and collecting residual developer remaining on the surface of the photosensitive member after the visual image is transferred to a transfer material, and a power source unit for applying to the charging rotary brush an oscillating voltage fulfilling the requirement of:.DELTA.t<L/Vpc or .DELTA.t>3.times.L/Vpcwherein .DELTA.t is the time taken for the oscillating voltage to vary between .+-.300 V above and below the central oscillating voltage value between the peaks of the voltage, L is the printing pitch, and Vpc is the speed of movement of the surface of the photosensitive member.

Abstract: The present invention comprises a photosensitive member supported for rotation within a unit case and a charger for uniformly charging the photosensitive member. The charger includes a conductive member in the form of a sheet held in contact with the photosensitive member and a supporting member having a non-flat cross section for supporting the conductive member, in which the charger applies a voltage formed of a direct-current voltage with an alternating-current voltage added thereto to the conductive member to thereby uniformly charge the photosensitive member. The charger is kept in place by having the supporting member fixed to vertical planes of the unit case at positions off vertical planes crossing the photosensitive member.

Abstract: A power supply for transmitting voltage to a device, including a web having a piezoelectric exterior layer for generating a voltage on the surface thereof in response to being deformed. The web is entrained about a roller arrangement to deform the piezoelectric exterior layer. Commutation brushes transfers the voltage generated on the surface of the piezoelectric exterior layer to the device. The roller arrangement in combination with the placement of commutation brushes and neutralization brushes are used to adjust the voltage to the device.

Abstract: The image forming method comprises, electrostatically charging an image bearing member using a contact charging assembly, forming an electrostatic latent image on the image bearing member thus charged, developing the electrostatic latent image with a magnetic toner to form a toner image and transferring the toner image to a transfer medium, wherein the charging assembly comprises a magnetic brush formed from conductive magnetic particles magnetically bound, and the charging assembly comes into contact with the image bearing member to charge the surface of the image bearing member by directly injecting charges into the electron level present on the surface of the image bearing member and the magnetic toner has a value of .sigma..D..delta. of 150 or less, where the value is obtained by multiplying i) a magnetization quantity .sigma. (Am.sup.2 /kg) in a magnetic field of 1K oersted as measured by a vibration magnetometer, ii) a weight average particle diameter (D.sub.4) D (.mu.

Abstract: In electrophotographic image forming, there are provided a charging device and an image forming apparatus provided with the charging device for forming an image including no or less image noise by sufficiently suppressing generation of image memory due to untransferred residual developer. The charging device has, for example, a charging brush formed of a roller and a strip-like fiber member having a plurality of piles wound therearound. The brush satisfies a condition of 0.7s<d<1.5s where d(mm) is a wound margin of the strip-like fiber member, and s(mm) is an average distance between the piles in a width direction of the fiber strip member.

Abstract: Disclosed herein is a conductive brush charging device for charging the surface of an image forming member. The conductive brush charging device includes a conductive brush located so as to rotate in contact with the image forming member, and a developer removing member formed of a porous material and located so as to be kept in surface contact with the conductive brush over the width thereof. When the conductive brush is rotated, the porous developer removing member rubs against the brush along its bristles to thereby remove a developer deposited to the brush. Since the developer removing member is formed of the porous material, the developer removed is retained in numerous pores of the porous developer removing member, thus achieving a long-term cleaning function.

Abstract: A brush contact charger charges a photosensitive drum of an image forming apparatus adopting an electrostatic recording system, and has a body having a brush for contacting a photosensitive drum and then charging the photosensitive drum, a reciprocating portion for reciprocating the body perpendicularly with respect to the proceeding direction of the photosensitive drum, and a guide member for supporting the body while guiding the reciprocal movement of the body. The charger charges the surface of the photosensitive drum while moving at a right angle with respect to the proceeding direction of the photosensitive drum and charges the surface of the photosensitive drum to an electrical potential having a nearly uniform distribution.

Abstract: A particle charging apparatus for charging a photo-sensitive drum by magnetically holding magnetic particles in a charging zone and impressing a charging bias on the magnetic particles. Adjacent to an opposed pole which is disposed on the back side of the photo-sensitive drum on the charging zone upstream side for forming a vertical magnetic field, an opposite polarity magnet or magnetic member is disposed such that a mainly horizontal magnetic field is formed on the drum by the opposed and adjacent poles. A vertical magnetic field is formed on the charging zone downstream side by a main pole and the opposed pole. A non-magnetic sleeve with the main pole therein is rotated in the direction opposite that of the drum, thus causing magnetic particles in the vertical magnetic field to be circulated toward the charging zone upstream side.

Abstract: In an magnetic brush charging apparatus, a following relation is satisfied, .rho..ltoreq.M/H.ltoreq.1.6 .rho., wherein H is a minimum gap distance (cm) between a cylinder and an image carrying member, .rho. is a density (g/cm.sup.3) of magnetic particles and M is an amount (g/cm.sup.2) of magnetic particles existing in a nip region coming in contact with the image carrying member.