Abstract: In order not to expel toner excessively when bias is applied, a cleanerless image forming apparatus includes a first developer charge amount controlling device 7, provided on a downstream side of a transfer device 5 in a moving direction of an image bearing member 1, e.g. a photosensitive drum, for applying a DC bias for making uniform a charge amount of residual developer remaining on the image bearing member 1, and/or a second developer charge amount controlling device 8, provided on a downstream side of the first developer charge amount controlling device 7 in a rotating direction of the image bearing member 1, for applying a DC bias for charging the residual developer in a normal polarity. An absolute value of a slope of the DC voltage applied to the first developer charge amount controlling device 7 and/or an absolute value of a slope of the DC voltage applied to the second developer charge amount controlling device 8 are equal to 2000 V/sec or smaller.

Abstract: An image forming apparatus includes transferring means for transferring, after a first color developer image is transferred onto an image receiving material in a first image forming station, a second color developer image onto the image receiving material in a second image forming station; wherein the first image forming station includes a first image bearing member, first charging means for electrically charging the first image bearing member, and a first developer carrying member for carrying the the first color developer to develop an electrostatic image formed on the first image bearing member with the first color developer; wherein the second image forming station includes a second image bearing member, second charging means for electrically charging the second image bearing member, and a second developer carrying member for carrying the the second color developer to develop an electrostatic image formed on the second image bearing member with the second color developer; the second developer carrying mem

Abstract: An image forming apparatus includes an image bearing body, a charging device for charging the image bearing body, a developing device for forming a developer image by developing an electrostatic image formed on the image bearing body, a transferring device for transferring the developer image to an image-receiving member, and first and second charge-applying devices. The first charge-applying device is provided at a downstream side of the transferring device and at an upstream side of the charging device in a moving direction of the image bearing body, for charging a residual developer remaining on the image bearing body after a transfer effected by the transferring device to a polarity opposite to a normal charging polarity of the developer.

Abstract: An image forming apparatus includes an image bearing member, a flexible changing member and a developing device. When a first area to be an image forming area of the image bearing member, is present in a nip portion, a superimposed voltage resulting from a direct current voltage and an alternating voltage having a peak to peak voltage smaller than an alternating voltage applied when a charging potential of the image bearing member is converged is applied to the charging member. When a part of a second area to be a non-image area of the image bearing member exists in the nip portion, a direct current voltage without an alternating voltage is applied to the charging member.

Abstract: An image forming apparatus includes an image bearing member; an electrostatic image forming unit for forming an electrostatic image on said image bearing member, the electrostatic image forming unit including a flexible charge member for electrically charging the image bearing member, the charge member forming a nip between the image bearing member and itself and is supplied with an oscillating voltage, wherein electroconductive particles are provided in the nip; and a developing unit for developing an electrostatic image formed on the image bearing member with a developer, the developing unit being capable of a residual developer on the image bearing member, wherein a frequency f (cycle/sec) of the oscillating voltage and a peripheral speed v (mm/sec) of the image bearing member satisfy |f/v|≧12 (cycle/mm).

Abstract: The invention provides an image forming apparatus provided with an image bearing body, and developer charge providing device for providing a charge thereby charging residual developer, remaining on the image bearing body after image transfer, to a normal polarity. The developer charge providing device charges an area of the image bearing body, and such area is further charged by the charging device. When the voltage applied to the developer charge providing device for charging such area is, varied, the voltage applied to the charging means for charging such area is also varied. Thus the image forming apparatus can execute uniform charging in stable manner over a prolonged period.

Abstract: An image forming apparatus includes a movable image bearing member, a charger means including a charge member for electrically charging the image bearing member with electroconductive particles between the charge member and the image bearing member and a developing member for developing a latent image with toner mixed with electroconductive particles. The latent image is formed on the image bearing member having been charged by the charging means, and a toner image provided by development of the latent image by the developing member is transferred onto a recording material. The electroconductive particles mixed in the toner is carried by the image bearing member and are fed to between the charge member and the image bearing member.

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: An image forming apparatus includes an image bearing member; a charging member, contactable to the image bearing member, for electrically charging the image bearing member at a charging position; developing means for developing an electrostatic image formed on the image bearing member with a developer; wherein when a first area on the image bearing member which is going to be an image formation area is at the charging position, the charging member moves with a peripheral speed difference relative to the image bearing member, and when a second area on the image bearing member which is a part of an area which is going to be a non-image formation area is at the charging position, the charging member moves substantially without a peripheral speed difference relative to the image bearing member, and wherein a collecting electric field is formed for collecting the developer from the second area to the developing means.

Abstract: When image forming is repeated with cleanerless image forming apparatus, “positive ghost”, which means that a preceding image is slightly left, occurs because a residual toner is not recovered by a developer. Even if an image forming apparatus with an electrically conductive brush or auxiliary device repeats image forming or continuously forms an image with a high image ratio, resistance of the brush increases because the residual toner is deposited on the electrically conductive brush. As a result, advantages of the electrically conductive brush which erases traces of the preceding image are lost. Therefore, in accordance with this invention there are provided an image forming apparatus which does not let image traces leave, and an image forming apparatus which prevents (or reduces) the resistance of auxiliary devices and cleans auxiliary devices.

Abstract: A developing device for an image forming apparatus capable of collecting a developer left on an image carrier with a so-called cleanerless process is disclosed. A ratio of a distance between the image carrier and a developer carrier at the boundary of a nip to a development gap at the center of the nip is selected to be 1.5 or less. This obviates the omission of the trailing edge of an image and granularity and enhances faithful reproduction of horizontal lines and dots despite the use of the cleanerless process.

Abstract: An image forming apparatus includes an image bearing member; electrostatic image forming means for forming an electrostatic image on said image bearing member, said electrostatic image forming means including a flexible charge member for electrically charging said image bearing member, said charge member forming a nip between said image bearing member and itself and is supplied with an oscillating voltage, wherein electroconductive particles are provided in the nip; and developing means for developing an electrostatic image formed on said image bearing member with a developer, said developing means being capable of a residual developer on said image bearing member, wherein a frequency f (cycle/sec) of the oscillating voltage and a peripheral speed v (mm/sec) of said image bearing member satisfy ¦f/v¦≧12 (cycle/mm).

Abstract: An image forming apparatus includes an image bearing member; a charge member, contactable to the image bearing member, for electrically charging the image bearing member, the charge member being capable of being supplied with a voltage; developing means for developing an electrostatic image formed on the image bearing member with a developer; wherein the charge member is rotatable so as to provide a first peripheral speed difference between a surface of charge member and a surface of the image bearing member when the image bearing member is charged for image formation; wherein there is provided a cleaning period for transferring the developer from the charge member to the image bearing member with a second peripheral speed difference, which is smaller than the first peripheral speed difference, between the surface charge member of and surface of the image bearing member, when a charging operation for the image formation is not effected to the image bearing member.

Abstract: A developing device for an image forming apparatus capable of collecting a developer left on an image carrier with a so-called cleanerless process is disclosed. A ratio of a distance between the image carrier and a developer carrier at the boundary of a nip to a development gap at the center of the nip is selected to be 1.5 or less. This obviates the omission of the trailing edge of an image and granularity and enhances faithful reproduction of horizontal lines and dots despite the use of the cleanerless process.

Abstract: A cleanerless image forming apparatus and a cleanerless image forming method facilitate the collection of residual toners after image transfer. The image forming apparatus includes a rotary endless latent carrier, a rotary charging brush for charging the rotary endless latent carrier, and a unit for forming an electrostatic latent image on the rotary endless latent carrier. The electrostatic latent image is developed on the rotary endless latent carrier by supplying polymerization toners simultaneously with the cleaning of residual polymerization toners therefrom. The polymerization toners on the rotary endless latent carrier are then transferred to a sheet.

Abstract: An image forming apparatus including a plurality of image bearing members, a plurality of image forming portions for forming images on the plurality of image bearing members, a plurality of primary transfer portions for transferring the images on the plurality of image bearing members onto an intermediate transfer member, secondary transfer portions for transferring the image on the intermediate transfer member onto a transfer material, and a controller for controlling the primary transfer portion to operate until an image area on the image bearing member on which an image is being formed at the point when an image formation stop instruction is issued passes a transfer region in the primary transfer portion opposing to the image bearing member.

Abstract: A process and an apparatus for cleaning an organic photosensitive drum in an image forming apparatus including a developer housing formed with an exposure window at a desired portion thereof and contained therein with an organic photosensitive drum, a developing roller, and a charging roller, the developing roller being configured to recover toner particles left on an outer surface of the organic photosensitive drum, for reuse thereof. The drum cleaning apparatus includes a cleaning film arranged between the charging roller and the exposure window while being in contact with the outer surface of the organic photosensitive drum, the cleaning film serving to remove foreign matters affixed to the outer surface of the organic photosensitive drum.

Abstract: To provide an image forming apparatus including: an image bearing member which is movable; an electrifying device which makes contact with the image bearing member and electrifies the image bearing member; a developing device for developing a latent image on the image bearing member by toner; and an abutting member which is provided on a downstream side in a moving direction of the image bearing member with respect to the electrifying device and the contacting portion of the image bearing member and abuts against the image bearing member, in which the image bearing member electrified by the electrifying device is exposed to have the latent image formed, a toner image formed on the image bearing member by the developing device is transferred to a recording material, and the developing device recovers residual toner on the image bearing member after transfer.

Abstract: A simultaneous developing/cleaning device includes a developer carrying member for carrying a layer of developer, the developer carrying member forming a developing zone where the layer of the developer is contacted to the developer carrying member and to an image bearing member carrying a latent image; and a charge application member for applying electric charge to the developer carried on the developer carrying member by electric discharge, the charge application member being provided upstream of the developing zone with respect to a moving direction of the developer carrying member.

Abstract: An image forming apparatus includes a movable image bearing member; charging means including a charge member for electrically charging the image bearing member with electroconductive particles between the charge member and the image bearing member; developing means for developing a latent image with toner mixed with electroconductive particles; wherein the latent image is formed on the image bearing member having been charged by the charging means, and a toner image provided by development of the latent image by the developing means is transferred onto a recording material; wherein the electroconductive particles mixed in the toner is carried by the image bearing member and is fed to between the charge member and the image bearing member; and a width A, measured in a direction perpendicular to a moving direction of the image bearing member, in which the electroconductive particle are present between the charge member and the image bearing member, a width B in which the developing means is capable of effecting

Abstract: The present invention provides an image forming apparatus, which has an image bearing body for bearing a toner image, transferring device for transferring a toner image on the image bearing body to a transferring material, a charging member for charging the image bearing body, having a residual toner after the transfer on a surface thereof by being brought into contact therewith, electrostatic image forming device for forming an electrostatic image on the image bearing body charged by the charging member, developing device for collecting the residual toner on the image bearing body while developing the electrostatic image on the image bearing body by using a toner charged in the same polarity as a charging polarity generated by the charging member, control device for controlling a voltage to be applied to the charging member, and a cleaning sequence for performing a cleaning of the charging member by applying a voltage not higher than a discharge threshold and equal to the polarity of the toner after a discha

Abstract: An image forming apparatus comprises an image bearing member for bearing an electrostatic image; a developing means for developing the electrostatic image on said image bearing member by toners charged with a predetermined polarity; a transfer means for transferring a toner image on said image bearing member to a transferring material; an electrifying means for inject-charging the image bearing member having transfer residual toners; an electrical conductive member provided and spaced apart from said image bearing member in a moving direction of the image bearing member downstream further than said transfer means and upstream further than said electrifying means; and an electrical field forming means for forming an alternative electrical field between said electrical conductive member and said image bearing member.

Abstract: An object of the present invention is to provide a developing apparatus which can prevent reduction in image density due to paper powder. A further object of the present invention is to provide 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 disposed below the toner carrying member and which is not substantially replenished with the toner.

Abstract: The present invention relates to an image forming apparatus in which a developing device has a developer bearing member for bearing and carrying a developer thereon, which is provided in opposed relationship with an image bearing member; and developer collecting means provided in opposed relationship with the developer bearing member and the image bearing member, and the developer collecting means collects any unused developer on the developer bearing member and any untransferred developer on the image bearing member.

Abstract: An image forming apparatus includes an image bearing member for bearing a toner image and a transfer device for transferring the toner image from the image bearing member onto a transfer material. A charging member contacts a surface of the image bearing member from which residual toner is not removed to electrically charge the image bearing member. The charging member is capable of temporarily collecting the residual toner. A cleaning device applies, to the charging member, a cleaning voltage for returning the toner to the image bearing member. An image forming device forms an electrostatic image on the image bearing member having been charged by the charging device. A developing device develops the electrostatic image on the image bearing member and collects the toner from the image bearing member. A controller controls the cleaning device to vary a cleaning condition of the charging member.

Abstract: An image forming apparatus includes an image bearing member with a recirculatively movable peripheral surface; and a device for forming electrostatic latent images on the peripheral surface of the image bearing member, the device including a charging member to which voltage is applicable to charge the image bearing member. The charging member includes a flexible member capable of forming a nip between itself and the image bearing member; a developer for developing the latent image with the use of developer composed of toner particles and electrically conductive particles. The developer is capable of cleaning the residual toner particles from the image bearing member. The electrically conductive particles transferred onto the image bearing member by the developer are delivered to the nip by the image bearing member. The flexible member is moved so that it maintains a peripheral velocity difference relative to the image bearing member.

Abstract: An image forming apparatus has an image forming unit for forming a toner image on a recording material, the image forming unit including an image bearing member for bearing a toner image, and a charging device provided with a magnetic particle layer contactable to the image bearing member to charge the image bearing member; and a determining device for determining an image forming condition of the image forming unit in accordance with a physical quantity relating to a toner amount introduced in the magnetic particle layer or deciding prohibition of the image forming operation of the image forming unit.

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 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: A detecting device includes: an actuator with its end placed in a conveying path of a moving object such as a sheet etc., pivotally supported by a rotary shaft so that it can sway as the moving object passes by; a slit arm integrally formed with the actuator and having a slit therein and an optical sensor disposed below the actuator. In this arrangement, the slit arm having a slit therein is placed in the path of the optical sensor. An urging portion for returning the actuator to the standby position is provided for the slit arm. The abutment surface P of the urging portion abutting the unit base of the optical sensor is formed inclined. A component force E causing the actuator to bounce, which is proportional to a repulsive force D normal to the abutment surface P when the abutment surface abuts the unit base abutment surface P, is smaller than the repulsive force D. Therefore, the distance of the bouncing of the actuator becomes smaller, thus preventing chattering.

Abstract: An image forming apparatus has an image forming body which is rotatable in a subsidiary scanning direction. A plurality of imagewise exposure devices for imagewise exposing the image forming body are arranged to face the image forming body and to be aligned in a straight line in a primary scanning direction perpendicular to the subsidiary scanning direction of the image forming body. A common supporting member is provided for supporting the plurality of exposure devices, and bearing members are provided on first and second ends of the common supporting member. The plurality of exposure devices are: (i) radially arranged on the common supporting member with respect to a rotation axis of the image forming body, and (ii) fixed on the supporting member with respect to the bearing members, and the image forming body is rotatable against the common supporting member through the bearing members.

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 electrophotographic apparatus including an electrically conductive brush roller for recovering and discharging a residual toner and removing paper dust which is located in contact with a photoreceptor drum. A positive voltage is applied to a transfer roller, whereupon the toner is charged positively. As a recording region on the photoreceptor drum with an electrostatic latent image formed thereon passes the brush roller, a voltage of a potential lower than the potential of the recording region is applied to the brush roller, and the brush roller recovers the residual toner. As a non-recording region on the photoreceptor drum without the latent image thereon passes the brush roller, on the other hand, a voltage of a potential higher than the potential of the non-recording region is applied to the brush roller, and the recovered toner is discharged onto the non-recording region. The discharged toner is returned to a developing roller after a charging process.

Abstract: According to the present invention, in the image forming apparatus in which so-called "cleaningless" is realized, no problems such as traces of paper powder, gray or foggy stripes and the like occur in a formed image. The image forming apparatus is provided with a brush for scratching toner remaining on the surface of the photosensitive drum and recovering paper powder adhering on the surface thereof. When the length of the brush extending from the root thereof to the photosensitive drum is taken as a?mm!, the length of the toughening member, toughening the brush materials, projecting from the root of the brush materials is taken as c?mm!, and the length of the portion of the brush, cutting into the photosensitive drum, is taken as b?mm!, the relationship among a?mm!, b?mm! and c?mm! satisfies the conditions that 0.3.ltoreq.(c/(a+b)).ltoreq.0.95, 0.1 ?mm!.ltoreq.b.ltoreq.1.5 ?mm!, and (a+b)<2 ?mm!.

Abstract: An image forming apparatus which collects residual toners on a latent image carrier in a developing unit. The image forming apparatus have a rotary endless latent image carrier; an image forming unit for forming an electrostatic latent image on the latent image carrier; a developing unit for developing the electrostatic latent image on the latent image carrier with a powdery developer and collecting residual toners on the latent image carrier at a same time; a transfer unit for transferring the developed image on the latent image carrier onto a sheet; a distribution member for distributing residual toners on the latent image carrier when in contact with the latent image carrier after image transfer; and a voltage supplying unit for supplying an AC voltage to the distribution member.

Abstract: An image forming apparatus including a photoreceptor, an electrically charging unit for evenly electrically charging the photoreceptor to a predetermined potential, a light exposure unit for exposing a surface portion of the evenly electrically charged photoreceptor to light so as to form an electrostatic latent image, a developing unit for causing toner to adhere to the photoreceptor surface portion exposed to light so as to develop the electrostatic latent image into a toner image, and a transferring unit to which a predetermined transferring voltage is applied for transferring the toner image to a sheet. Before the tip end of the toner image reaches the position opposite to the transferring unit but after the tip end of the sheet has reached the position opposite to the transferring unit, the application of the predetermined transferring voltage to the transferring unit is started.

Abstract: A method of controlling the charging operation of the contact charger of an electrophotographic apparatus including a photosensitive drum and a developing means for charging a toner with a negative voltage, the photosensitive drum and developing means being normally supplied with a negative voltage during printing, which includes the steps of: supplying a negative charging voltage of a specified level to the contact charger for a first interval defined as at least one initial rotation of the photosensitive drum in warm-up with the developing means not being supplied with a voltage, cutting off the negative charging voltage, and supplying a negative developing bias voltage which is lower than the surface voltage of the photosensitive drum to the developing means for a second interval defined as the interval before the stopping of the rotation of the photosensitive drum after the first period.

Abstract: An image forming apparatus includes: an image support medium; a charging member for charging the surface of the image support medium in contact with the surface of it; an exposure device for irradiating with light the surface of the image support medium charged by the charging member to form a static latent image; a developing device for supplying developer to the static latent image formed on the image support medium to develop the latent image and for removing the leftover developer on the image support medium; a transfer device for transferring the developer image, which has been developed on the image support medium by the developing device, to a member to be transferred; and a scraping member for scraping foreign matter such as dust and paper particles on the image support medium.

Abstract: A laser printer performing a developing operation on a positively chargeable photosensitive drum with using positively chargeable toners. The printer includes photosensitive drum, a laser scanner unit for forming an electrostatic latent image on the photosensitive drum, a developing roller for developing the electrostatic latent image by a toner layer consisting of toners having positively chargeable characteristic, a thickness regulation blade for regulating the thickness of the toner layer on the developing roller such that the amount of toners in the toner layer is not more than 0.5 mg/cm.sup.2, a scorotoron charger confronting the photosensitive drum in out of contact therefrom for charging the rotating photosensitive drum to the positive polarity, and a transfer roller for transferring the toner image onto a printing sheet. By the thickness regulation of the toner layer, each toner is surely imparted with positive polarity.

Abstract: In an image forming method for developing an electrostatic latent image on an image bearing member by using a two-component magnetic developer includes the steps of supporting and conveying a magnetic developer directly on the surface of a permanent magnet with a plurality of magnetic poles provided on the surface and performing both the removal of the residual toner remaining on the surface of the image-bearing member and the development of the electrostatic latent image while rubbing said surface with said magnetic brush. The magnetic carriers in the magnetic developer have average particle sizes of 5 to 20 .mu.m and opposite to toner in polarity of charge, the magnetization .sigma..sub.1000 in a magnetic field of 1000 Oe is 50 emu/g or less. Nonspherical magnetic toner or non-magnetic toner made by a polymerization process and magnetic carriers may be used.

Abstract: An image forming apparatus performs an electrophotographic process including a uniform charging step, an exposure step, a developing step and a transfer step on a photosensitive drum which is driven so that an image is formed on a recording medium.

Abstract: An image forming apparatus for forming an image on a sheet, including a rotary endless latent image carrier, an image forming device for forming an electrostatic latent image on a latent image carrier, a developing device for developing the electrostatic latent image on the latent image carrier with powdery developers and collecting residual toners on the latent image carrier at the same time, a transfer device for transferring a developed image on the latent image carrier onto a sheet, a distribution roller having independent foam perforations for distributing residual toners on the latent image carrier when in contact with the latent image carrier after image transfer, and a power supply for supplying an AC voltage to the distribution member. The distribution member is made of a conductive foam member having a pore at a surface contacting with the latent image carrier and the roller rotates in a direction opposite to a rotational direction of the latent image carrier at a peripheral velocity of 1.1 to 1.

Abstract: An image forming apparatus comprises a contact charging member for contacting a photosensitive drum and charging it with electricity, an exposer for exposing the charged photosensitive drum to light and forming an electrostatic latent image thereon, a developing device for visualizing the electrostatic latent image formed on the photosensitive drum by means of coloring powder, a transferring device for transferring the image visualized by the developing device onto a recording medium and a deelectrifier for deelectrifying the photosensitive drum after transferring the image by the transferring device. Any residual coloring powder remaining on the surface of the photosensitive drum after transfer is collected and cleaned by the developing device simultaneously with the developing operation.

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: An image forming apparatus for forming a latent image on a photosensitive member, developing the latent image by a developing device to transfer the developed image onto a recording paper, and cleaning residual toner on the photosensitive member after transferring by the developer. The photosensitive member has a hardness such that a conical diamond produces on a surface of the photosensitive member a scratch of 30 .mu.m or greater but no more than 180 .mu.m in width, when the diamond scratches the surface of the photosensitive member under a vertical load of 50 g and relative speed of 100 mm/min, the diamond having a conical angle of 120.degree. and hemisphere shaped leading edge with a radius of 0.2 mm. The image forming apparatus further includes at least one rotational brush provided in contact with the photosensitive member under the conditions of :100 mm.gtoreq.W.times..vertline.Vr-Vp.vertline./Vp.gtoreq.