Abstract: A developing unit includes a developing roller which rotates about a rotational axis to supply toner to a photoreceptor, the developing roller including: a cylindrical core portion which includes an electric conductor; a first resistive layer which covers a cylindrical surface of the core portion; a second resistive layer which covers the first resistive layer, and has electric-resistivity lower than that of the first resistive layer; and a current leakage control member which prevents leakage of electric current from the core portion toward the second resistive layer through an end of the developing roller along a direction of the rotational axis.

Abstract: Provided is a developing device including: a developing container including a developer replenishing port from which the developer is replenished, and a developer discharge port which is provided on a downstream side of one of the conveyance paths and from which surplus developer is discharged; and a discharge regulating portion provided to one of the plurality of stirring members which is arranged in the one of the conveyance paths, in which the discharge regulating portion includes a regulating member arranged so as to face the developer discharge port, for regulating movement of the developer to the developer discharge port side, and a decelerating conveyance member arranged between the helical blade and the regulating member, for partially reducing a conveying speed of the developer in the one of the conveyance paths.

Abstract: A developing device is provided for visualizing an electrostatic latent image previously formed on the surface of an image carrier as a toner image. The developing device has a developing roller placed at a position facing the image carrier, carrying a toner on the surface thereof, conveying the toner and flying the conveyed toner onto the surface of the image carrier; and a resin layer coated on the surface of the developing roller. The absolute value of the difference in charge between the toners in the upper and lower layers of the toner layer formed on the developing roller as the toner carried on the developing roller is 6 ?C/g or less.

Abstract: This invention relates to a developing device 18 for use in an image-forming apparatus comprising a developing roller 100 having a conductive base surface 19 which may be covered with a resin layer 17 layer comprising an ion conductive material and a silicone-modified urethane resin having an ether structure.

Abstract: A developing device is provided with a developing roller arranged to face a photoconductor for forming an electrostatic latent image and adapted to supply a toner to the photoconductor, an agitating member for agitating a developer, a supply roller that holds the developer agitated by the agitating member, and supplies the toner to an area facing the developing roller; a restricting member for blocking the developer supplied onto the supply roller and restricting the amount of the developer conveyed by the supply roller, and an intermediate roller including a first magnetic pole facing in a direction toward the staying developer by being restricted by the restricting member for attracting the staying developer and arranged at such a position as to face the developer blocked by the restricting member. Thus, the developing device can avoid image quality deterioration even when a developing process continues over a long period of time.

Abstract: A developing unit includes a developing roller which rotates about a rotational axis to supply toner to a photoreceptor, the developing roller including: a cylindrical core portion which includes an electric conductor; a first resistive layer which covers a cylindrical surface of the core portion; a second resistive layer which covers the first resistive layer, and has electric-resistivity lower than that of the first resistive layer; and a current leakage control member which prevents leakage of electric current from the core portion toward the second resistive layer through an end of the developing roller along a direction of the rotational axis.

Abstract: A developing device includes a container for containing toner, a rotatable shaft provided in the container, a spiral shaped blade formed on an outer circumference of the shaft, and a first spiral member for conveying the toner in the longitudinal direction of the shaft by means of rotation. In addition, a toner removing member is provided for removing the toner attached to the first spiral member. Then, by rotation of the first spiral member, the toner removing member is moved in the longitudinal direction of the shaft and the direction that is orthogonal to the longitudinal direction of the shaft so as to be in contact with the surface of the first spiral member. Accordingly, it is possible to adequately scrape the toner off the spiral shaped blade and the shaft, thereby effectively prevent an aggregation of toner from occurring.

Abstract: A developing device visualizing an electrostatic latent image previously formed on the surface of an image carrier as toner image, comprising: a developing roller placed at a position facing the image carrier, carrying a toner on the surface thereof, conveying the toner and flying the conveyed toner onto the surface of the image carrier; and a resin layer coated on the surface of the developing roller, wherein the absolute value of the difference in charge between the toners in the upper and lower layers of the toner layer formed on the developing roller as the toner carried on the developing roller is 6 ?C/g or less.

Abstract: The surface of a developing roller is coated with a phenol resin layer at a higher level in triboelectric series than a toner. A positively charged toner supplied from a magnetic roller onto the developing roller is negatively charged by friction with the phenol resin layer at the higher level in the triboelectric series. As a result, the positive charge of the toner is cancelled out, and the charge amount of toner per unit weight on the developing roller (Q/M)s decreases. Applying this principle, relationship between (Q/M)s and the charge amount of toner per unit weight on the magnetic roller (Q/M)m satisfies (Q/M)s<(Q/M)m.

Abstract: A control part 33 rotates a developer roller 21a at a second rotation speed, which is slower than a normal rotation speed during an image formation period (first rotation speed), during a non-image formation period while a heater 14 is in use. This prevents deformation of the developer roller 21a caused by radiant heat from a photoconductive drum 41, effectively prevents the appearance of image fogging, concentration unevenness, and the like, and also suppresses toner deterioration in a development unit 21.

Abstract: A developing device includes a developing sleeve for supplying toner particles to a latent image area on a peripheral surface of a photoconductive drum while rotating about an axis. The developing sleeve has a permanent magnet therein. Two magnetic members are provided in the developing device and face opposite ends of a peripheral surface of the developing sleeve at a predetermined distance from the developing sleeve. The magnetic members have arc-shaped inner surfaces. A blade is spaced a predetermined distance from a central portion of the peripheral surface of the developing sleeve. The blade adjusts the amount of toner particles supplied to the photoconductive drum. The gap between the arc-shaped inner surface of the magnetic member and the peripheral surface of the developing sleeve gradually increases from upstream to downstream in a rotational direction of the developing sleeve.

Abstract: A developing device (50) includes a developing sleeve (53) for supplying toner particles (T) to a latent image area (22) on a peripheral surface of a photoconductive drum (20) while rotating about a central shaft (534). The developing sleeve (53) has an immovable sleeve magnet (533) therein. Two magnetic members (82) are disposed in opposite end portions of the developing sleeve (53) and are spaced a predetermined distance from the peripheral surface of the developing sleeve. Each magnet member (82) has an arc shape. A magnetic member magnet (83) is mounted in the magnet member (82) and faces a sleeve magnet (533) so that opposite facing portions of the magnetic member magnet (83) and the sleeve magnet (533) have the same polarity. With this construction, toner particles are prevented from leaking from the end portions of the developing sleeve (53).

Abstract: In an image forming apparatus, a control section 41 adjusts the surface potential of a photoconductor or the developing potential of a developer carrying member based on the detection result of a surface potential sensor 44, and performs first correction whereby, relative to the reference value of the applied bias of a charger 2 or the developing bias of the developer carrying member in a developing unit 4 as observed during potential adjustment, the applied bias or the developing bias is varied so as to keep constant the potential difference between the surface potential of the photoconductor and the developing potential of the developer carrying member during image formation. The control section also performs second correction whereby the applied bias or the developing bias is restored to the reference value over a predetermined period after the completion of continuous image formation.

Abstract: A developing device includes a developing sleeve for supplying toner particles to a latent image area on a peripheral surface of a photoconductive drum while rotating about an axis. The developing sleeve has a permanent magnet therein. Two magnetic members are provided in the developing device and face opposite ends of a peripheral surface of the developing sleeve at a predetermined distance from the developing sleeve. The magnetic members have arc-shaped inner surfaces. A blade is spaced a predetermined distance from a central portion of the peripheral surface of the developing sleeve. The blade adjusts the amount of toner particles supplied to the photoconductive drum. The gap between the arc-shaped inner surface of the magnetic member and the peripheral surface of the developing sleeve gradually increases from upstream to downstream in a rotational direction of the developing sleeve.

Abstract: A developing device (50) includes a developing sleeve (53) for supplying toner particles (T) to a latent image area (22) on a peripheral surface of a photoconductive drum (20) while rotating about a central shaft (534). The developing sleeve (53) has an immovable sleeve magnet (533) therein. Two magnetic members (82) are disposed in opposite end portions of the developing sleeve (53) and are spaced a predetermined distance from the peripheral surface of the developing sleeve. Each magnet member (82) has an arc shape. A magnetic member magnet (83) is mounted in the magnet member (82) and faces a sleeve magnet (533) so that opposite facing portions of the magnetic member magnet (83) and the sleeve magnet (533) have the same polarity. With this construction, toner particles are prevented from leaking from the end portions of the developing sleeve (53).

Abstract: A control part 33 rotates a developer roller 21a at a second rotation speed, which is slower than a normal rotation speed during an image formation period (first rotation speed), during a non-image formation period while a heater 14 is in use. This prevents deformation of the developer roller 21a caused by radiant heat from a photoconductive drum 41, effectively prevents the appearance of image fogging, concentration unevenness, and the like, and also suppresses toner deterioration in a development unit 21.

Abstract: A developing device includes a container for containing toner, a rotatable shaft provided in the container, a spiral shaped blade formed on an outer circumference of the shaft, and a first spiral member for conveying the toner in the longitudinal direction of the shaft by means of rotation. In addition, a toner removing member is provided for removing the toner attached to the first spiral member. Then, by rotation of the first spiral member, the toner removing member is moved in the longitudinal direction of the shaft and the direction that is orthogonal to the longitudinal direction of the shaft so as to be in contact with the surface of the first spiral member. Accordingly, it is possible to adequately scrape the toner off the spiral shaped blade and the shaft, thereby effectively prevent an aggregation of toner from occurring.

Abstract: A process unit including a photoconductor unit having a photoconductor drum, a developing unit having a developing roller disposed in a development housing, and a support shaft means for supporting the developing unit pivotably relative to the photoconductor unit. The developing roller is disposed such that its surface is pressed against the surface of the photoconductor drum in a developing zone. The photoconductor drum and the developing roller are rotationally driven such that their respective surfaces move from below to above in the developing zone.

Abstract: A process unit comprising a photoconductor unit and a developing unit supported pivotably via a support shaft. The photoconductor unit and the developing unit each have a pair of support side walls having support holes formed on the same axis. One pair of the support side walls define a pair of inner support side walls having an outside width smaller than the inside width of the other pair of the support side walls, while the other pair of the support side walls define a pair of outer support side walls. The pair of outer support side walls and the pair of inner support side walls are supported via the support shaft passing through the respective support holes. One end of the support shaft is supported by one of the outer support side walls via a bearing member detachably mounted in the support hole of the one of the outer support side walls.

Abstract: A developer unit of the present invention has an agitating paddle which agitates a developer containing a magnetic carrier and a non-magnetic toner, and a toner is supplied from the toner hopper according to an output of a toner concentration sensor. After an agitation is finished which is performed when the power is turned on, the agitating paddle is periodically operated to agitate the developer. During the agitation, a toner concentration controller shifts a reference level with which the output of the toner concentration sensor is compared from a predetermined level to a higher level and then stepwisely returns it to the predetermined level.