Abstract: An image forming apparatus which can quickly remove remaining toner even after it has been emergently stopped when it forms an image by the use of an intermediate transfer member. An image forming apparatus for primary-transferring a toner image formed on a photosensitive drum to an intermediate transfer belt by a primary transfer roller, and secondary-transferring the primary-transferred image to a recording material to thereby form an image has a secondary cleaning portion for applying a bias to a plurality of fur brushes, wherein during ordinary image forming, biases of different polarities are applied to the plurality of fur brushes to thereby effect cleaning, and during a returning operation after emergent stoppage, biases of the same polarity are applied to the plurality of fur brushes to thereby effect cleaning.

Abstract: A developing apparatus includes a developer carrying body, opposed to an image bearing body bearing an electrostatic image, for carrying a magnetic developer, a regulating member, provided under the developer carrying body, for regulating an amount of the developer on the developer carrying body, a first magnetic pole provided in the developer carrying body and near a portion regulated by said regulating member, a second magnetic pole, provided at an upstream side of the first magnetic pole in a moving direction of the developer carrying body, for forming a repulsive magnetic field with the first magnetic pole, a first screw for agitating and carrying a developer dropped from the developer carrying body by the repulsive magnetic field, and a second screw for forming a developer circulating path with the first screw and receiving a replenished developer, wherein the first screw has a developer carrying capability lower than a developer carrying ability of the second screw.

Abstract: A developing apparatus includes a developer container for containing a developer comprising magnetic carrier and non-magnetic toner produced through polymerization method; a developer carrying member, provided in an opening of the developer container, for carrying the developer; detecting means for detecting a toner content in the developer, the detecting means including a coil sensor and detecting the toner content using magnetic permeability of the developer.

Abstract: A developing device includes a developer bearing member for bearing and conveying a developer having a toner and a carrier, a first magnetic pole arranged in the developer bearing member, a second magnetic pole arranged in the developer bearing member, a polarity of the second magnetic pole being opposite to a polarity of the first magnetic pole. The second magnetic pole is adjacent to the first magnetic pole and is arranged on a downstream side of the first magnetic pole in a moving direction of the developer bearing member. A regulating member regulates a layer thickness of the developer borne by the developer bearer. The regulating member is arranged in the vicinity of the second magnetic pole and a concentration detector for detecting a concentration of the toner in the developer.

Abstract: The present invention relates to an image forming apparatus which has an image bearing member for bearing a latent image, charging device for charging the image bearing member by bringing ears of electrically conductive particles into contact with the image bearing member, developing device for visualizing the latent image formed on the image bearing member as a toner image by using a developer containing toner and carrier after the image bearing member has been charged by the charging device, a permeability of the carriers being different from a permeability of the electrically conductive particles, density control device for controlling density of the developer within the developing device, the density control device detecting a permeability of the developer, comparing a detected signal value based on the detected result with a reference value, and controlling the density of the developer on the basis of the comparison result, and reference value correcting device for correcting the reference value, the ref

Abstract: An image forming apparatus includes a plurality of image forming stations forming images of different colors on a transfer material and is provided along a direction of conveyance of the transfer material by a conveying system, in which a toner replenishing system is operated on the basis of a result of a detected magnetic permeability a detecting device and the developer, which is not transferred to the transfer material but and, which remains on an image bearing member is collected by a developing system.

Abstract: A developing device comprises a developer bearing member for bearing and conveying a developer having a toner and a carrier, a first magnetic pole arranged in the developer bearing member, a second magnetic pole arranged in the developer bearing member, a polarity of the second magnetic pole being opposite to a polarity of the first magnetic pole, and the second magnetic pole being adjacent to the first magnetic pole and arranged on a downstream side of the first magnetic pole in a moving direction of the developer bearing member, a regulating member for regulating a layer thickness of the developer borne by the developer bearer, the regulating member being arranged in the vicinity of the second magnetic pole and a concentration detector for detecting a concentration of the toner in the developer.

Abstract: An image forming apparatus uses a toner wherein when a weight average diameter of the initial toner in a developing device is set to D1, and a weight average diameter of a toner forming an initial toner image on an image bearing member is D2, such that D1≧D2 is satisfied.

Abstract: An image forming method includes (i) a charging step of using a charging device including conductive magnetic particles, a rotatable conductive-magnetic-particle carrying member for carrying and conveying the conductive magnetic particles, and a plurality of magnetic-field generation means provided within the conductive-magnetic-particle carrying member, and charging a surface of an image bearing member by applying a voltage to the conductive-magnetic-particle carrying member and causing the conductive magnetic particles to contact the image bearing member, (ii) a latent-image forming step of forming an electrostatic latent image on the charged surface of the image bearing member, and (iii) a developing step of using a developing device facing the image bearing member and including a two-component developer including a toner and magnetic carrier particles, a developer carrying member for carrying the two-component developer, and a plurality of magnetic-field generation means provided within the developer carr

Abstract: An image forming apparatus comprises a charging member, an image bearing member and a developer bearing member. The charging member comprises a first magnetic field generating device, wherein a first magnetic field with a first magnetic pole closest to the image bearing member has a half-value width &agr;°. Measuring from a center of the charging member, an angle between a closest point of the image bearing member and a maximum magnetic flux density of the first magnetic pole is &thgr;c°. The developer bearing member comprises a second magnetic field generating device, wherein a second magnetic field with a second magnetic pole closest to the image bearing member has a half-value width &bgr;°. Measuring from a center of the developer bearing member, an angle between a closest point of the image bearing member and a maximum magnetic flux density of the second magnetic pole is &thgr;d°.

Abstract: In the image forming machine of the invention, a two-component type developer has a spherical magnetic powder dispersion type carrier, which has a weight average particle diameter of from 15 to 60 .mu.m. The external additive is present in the form of particles on the toner particle, and comprises inorganic oxide fine particles A having a shape factor SF-1 of from 100 to 130, and non-spherical inorganic oxide fine particles B, having a shape factor SF-1 larger than 150 and particles B having been obtained by combining a plurality of component particles.

Abstract: A developing device having a developer bearing member for carrying thereon a developer having toner and carrier and conveying the developer to a developing area, an agitating member for agitating the developer, a rotation radius R (m) of the agitating member being 5.0.times.10.sup.-3 (m)<R<8.0.times.10.sup.-3 (m), and a density sensor for detecting a density of the toner in the developer, the density sensor detecting any change in the density of the toner as a change in a magnetic permeability of the developer, wherein when a shortest distance between an outermost surface of the agitating member and a detecting surface of the sensor is defined as Dmin (m) and a half length of the detecting surface of the sensor in a plane perpendicular to a rotary axis of the agitating member is defined as r, 0 (m)<Dmin<1.0.times.10.sup.31 3 (m) and 0.4<r/R<0.75.

Abstract: A developing apparatus has a developer bearing member disposed in opposed relationship with an image bearing member bearing an electrostatic image thereon with a gap of 6.times.10.sup.-4 m or less with respect to the image bearing member, and bearing and conveying a developer thereon. The developer bearing member is moved in a direction opposite to the direction of movement of the image bearing member in the portion opposed to the image bearing member, and the developer has a non-magnetic toner and a carrier of which the magnetization rate in a magnetic field of 1000 gauss is equal to or greater than 30 emu/cm.sup.3 and equal to or less than 200 emu/cm.sup.3 and the specific resistance at electric field intensity of 5.times.10.sup.4 V/m is 10.sup.12 .OMEGA.cm or greater. The developing apparatus further has applying means for applying a bias voltage having a vibration component to the developer bearing member.