Abstract: An image forming apparatus has a photosensitive member, a charging member, an exposing device, a developing device, a transfer member, a polishing member, a driving device, a voltage applying device, a torque detector, and a control portion. The photosensitive member has a photosensitive layer and a surface protection layer formed on the surface of the photosensitive layer. The polishing member has an elastic layer on its circumferential surface, and rotates with a linear velocity difference from that of the photosensitive member. The torque detector detects the torque of the driving device. The control portion estimates an attachment condition of discharge products to the surface of the photosensitive member based on the torque of the driving device detected by the torque detector. When the torque is equal to or higher than a predetermined value, the control portion performs an image degradation suppression process.

Abstract: A developing device includes a developing roller, a conveyor roller and a developer stirring unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position. The developing roller includes a fixed first magnet and a first sleeve. The conveyor roller is arranged to face the developing roller at a predetermined facing position. The conveyor roller includes a fixed second magnet and a second sleeve. The developer stirring unit stirs the developer and supplies the developer to the conveyor roller. The first magnet includes a first magnetic pole composed of a predetermined magnetic pole and a second magnetic pole arranged downstream of and adjacent to the first magnetic pole and having the same polarity as the first magnetic pole. The developer is transferred from the developing roller to the conveyor roller after passing through a repulsive magnetic field formed by the first and second magnetic poles.

Abstract: An image forming apparatus has a photosensitive member, a charging member, an exposing device, a developing device, a transfer member, a polishing member, a driving device, a voltage applying device, a torque detector, and a control portion. The photosensitive member has a photosensitive layer and a surface protection layer formed on the surface of the photosensitive layer. The polishing member has an elastic layer on its circumferential surface, and rotates with a linear velocity difference from that of the photosensitive member. The torque detector detects the torque of the driving device. The control portion estimates an attachment condition of discharge products to the surface of the photosensitive member based on the torque of the driving device detected by the torque detector. When the torque is equal to or higher than a predetermined value, the control portion performs an image degradation suppression process.

Abstract: A developing device includes a development roller, a layer-thickness limiting member, and a first screw. The development roller includes a fixed magnet and a sleeve. The first screw supplies developer to the development roller while conveying the developer in a first conveyance direction. The sleeve includes a plurality of recesses. Each of the recesses has an elongated shape, and a downstream end and an upstream end in the first conveyance direction. The downstream end is located farther downstream in a rotational direction of the sleeve than the upstream end. When the developer in each of the recesses passes the layer-thickness limiting member, the developer moves upstream in the first conveyance direction.

Abstract: A discharging member includes an electrically conductive knit fabric, a support member, and a first magnet member. The conductive knit fabric is knitted into a cylindrical shape with use of yarn formed by twisting together a plurality of metal fibers. The support member is cylindrical shaped and inserted in the conductive knit fabric. The first magnet member is placed inside the support member. With the conductive knit fabric grounded or with a voltage applied to the conductive knit fabric, the discharging member is placed in noncontact with a discharged member in such a fashion that the first magnet member is opposed to the discharged member with the support member and the conductive knit fabric interposed therebetween.

Abstract: A developing device includes a housing, a developing roller, a developer stirring member, and a layer thickness regulating member. The developing roller includes a stationary magnet and a sleeve. The stationary magnet includes a first magnetic pole having a specific polarity, and a second magnetic pole lying downstream of the first magnetic pole and having the same polarity as the first magnetic pole. In an entire inter-pole region between the first magnetic pole and the second magnetic pole, the stationary magnet produces a magnetic force including a horizontal component that keeps the specific polarity and has a value greater than zero (mT). The inter-pole region includes a flat area where a horizontal magnetic force component having a minimum absolute value exits and the horizontal magnetic force component changes within a range of 0.5 (mT) or less, the flat area extending over a range of 10 degrees or more.

Abstract: A developing device includes a developing roller and a conveyor roller. The developing roller includes a first magnet. The conveyor roller includes a second magnet. The first magnet includes a first magnetic pole and a second magnetic pole. The second magnet includes a third magnetic pole and a fourth magnetic pole. The first and fourth magnetic poles are magnetic poles having the same polarity. One of the second and third magnetic poles is a magnetic pole having the same polarity as the first magnetic pole. The other of the second and third magnetic poles is a magnetic pole having a polarity different from the first magnetic pole. The developer is transferred from the conveyor roller to the developing roller by the third and second magnetic poles. The developer is transferred from the developing roller to the conveyor roller by the first and fourth magnetic poles.

Abstract: A developing device includes a developing roller, a conveyor roller, a developer stirring unit and a development bias applying unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position and supplies the toner. The conveyor roller is arranged to face the developing roller at a predetermined facing position and supplies the developer to the developing roller. The development bias applying unit applies development biases to the first sleeve of the developing roller and the second sleeve of the conveyor roller during a developing operation of developing the electrostatic latent image on the photoconductive drum with the toner. The development bias applying unit applies the development biases such that a shifting electric field to move the toner on the first sleeve of the developing roller toward the second sleeve of the conveyor roller is formed at the facing position during the developing operation.

Abstract: A developing device includes a housing, a developing roller, a developer stirring member, and a layer thickness regulating member. The developing roller includes a stationary magnet and a sleeve. The stationary magnet includes a first magnetic pole having a specific polarity, and a second magnetic pole lying downstream of the first magnetic pole and having the same polarity as the first magnetic pole. In an entire inter-pole region between the first magnetic pole and the second magnetic pole, the stationary magnet produces a magnetic force including a horizontal component that keeps the specific polarity and has a value greater than zero (mT). The inter-pole region includes a flat area where a horizontal magnetic force component having a minimum absolute value exits and the horizontal magnetic force component changes within a range of 0.5 (mT) or less, the flat area extending over a range of 10 degrees or more.

Abstract: A discharging member includes an electrically conductive knit fabric, a support member, and a first magnet member. The conductive knit fabric is knitted into a cylindrical shape with use of yarn formed by twisting together a plurality of metal fibers. The support member is cylindrical shaped and inserted in the conductive knit fabric. The first magnet member is placed inside the support member. With the conductive knit fabric grounded or with a voltage applied to the conductive knit fabric, the discharging member is placed in noncontact with a discharged member in such a fashion that the first magnet member is opposed to the discharged member with the support member and the conductive knit fabric interposed therebetween.

Abstract: A developing device includes a developing roller, a conveyor roller and a developer stirring unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position. The developing roller includes a fixed first magnet and a first sleeve. The conveyor roller is arranged to face the developing roller at a predetermined facing position. The conveyor roller includes a fixed second magnet and a second sleeve. The developer stirring unit stirs the developer and supplies the developer to the conveyor roller. The first magnet includes a first magnetic pole composed of a predetermined magnetic pole and a second magnetic pole arranged downstream of and adjacent to the first magnetic pole and having the same polarity as the first magnetic pole. The developer is transferred from the developing roller to the conveyor roller after passing through a repulsive magnetic field formed by the first and second magnetic poles.

Abstract: A developing device includes a developing roller, a conveyor roller, a developer stirring unit and a development bias applying unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position and supplies the toner. The conveyor roller is arranged to face the developing roller at a predetermined facing position and supplies the developer to the developing roller. The development bias applying unit applies development biases to the first sleeve of the developing roller and the second sleeve of the conveyor roller during a developing operation of developing the electrostatic latent image on the photoconductive drum with the toner. The development bias applying unit applies the development biases such that a shifting electric field to move the toner on the first sleeve of the developing roller toward the second sleeve of the conveyor roller is formed at the facing position during the developing operation.

Abstract: A discharge member includes an electro conductive knit fabric and a support member. The electro conductive knit fabric is knitted in a cylindrical shape using twisted yarn made of twisted metal fibers. The support member is cylindrical and is inserted in the electro conductive knit fabric. The discharge member is disposed to face a member to be discharged in a noncontact manner, in a state where the electro conductive knit fabric is grounded or a voltage is applied to the electro conductive knit fabric.

Abstract: A developing device includes a developing roller and a conveyor roller. The developing roller includes a first magnet. The conveyor roller includes a second magnet. The first magnet includes a first magnetic pole and a second magnetic pole. The second magnet includes a third magnetic pole and a fourth magnetic pole. The first and fourth magnetic poles are magnetic poles having the same polarity. One of the second and third magnetic poles is a magnetic pole having the same polarity as the first magnetic pole. The other of the second and third magnetic poles is a magnetic pole having a polarity different from the first magnetic pole. The developer is transferred from the conveyor roller to the developing roller by the third and second magnetic poles. The developer is transferred from the developing roller to the conveyor roller by the first and fourth magnetic poles.

Abstract: An image forming apparatus includes a rotator, a driving control portion, and a layer thickness control portion. The rotator conveys toner to contact position to an image carrying member, and supplies toner to the image carrying member at the contact position. The driving control portion controls rotation of the rotator so as to rotate the rotator during a developing period, and stop the rotation of the rotator after a set time has elapsed since an end of the developing period. The layer thickness control portion causes the rotator to carry toner by controlling a potential difference between a potential of the rotator and a predetermined potential so that toner on the rotator at the contact position has a first layer thickness during the developing period and has a second layer thickness while the rotation of the rotator is stopped, the second layer thickness being thicker than the first layer thickness.

Abstract: An image forming apparatus includes a rotator, a driving control portion, and a layer thickness control portion. The rotator conveys toner to contact position to an image carrying member, and supplies toner to the image carrying member at the contact position. The driving control portion controls rotation of the rotator so as to rotate the rotator during a developing period, and stop the rotation of the rotator after a set time has elapsed since an end of the developing period. The layer thickness control portion causes the rotator to carry toner by controlling a potential difference between a potential of the rotator and a predetermined potential so that toner on the rotator at the contact position has a first layer thickness during the developing period and has a second layer thickness while the rotation of the rotator is stopped, the second layer thickness being thicker than the first layer thickness.

Abstract: An image forming apparatus includes an image carrier, a developer carrier, a bias applying section, a leakage detecting section, and a bias controlling section. The developer carrier carries developer in the form of a layer of magnetized filaments to supply toner to the image carrier. The bias applying section applies to the developer carrier a development bias including a direct current voltage VmagDC and an alternating current voltage VmagAC superposed on each other. The leakage detecting section causes a discharge between the image carrier and the developer carrier and detects a leakage voltage when the discharge occurs. The leakage detecting section performs the leakage voltage detection in a blank region of the image carrier bearing no electrostatic latent image. The bias controlling section determines an alternating current voltage VmagAC according to a detected leakage voltage, and a frequency of the alternating current voltage VmagAC according to the voltage VmagAC.

Abstract: A developing unit includes a casing, a developer carrier, a developer conveying path, a developer conveying member, and a layer thickness regulator. The developer carrier is driven to rotate in the casing and carries a toner on the circumferential surface. The developer conveying member is located in the developer conveying path and driven to rotate so as to convey the developer in a second direction and to supply the toner to the developer carrier. The layer thickness regulator is spaced from the developer carrier, and regulates a layer thickness of the developer supplied to the developer carrier. The developing unit is configured to satisfy a condition of 2.0<Vd/Vs<7.0, where Vd denotes a circumferential velocity of the developer carrier and Vs denotes a circumferential velocity of the developer conveying member.

Abstract: In an image forming apparatus, a coating layer of each of a photoconductor drum and a collecting roller has been formed by a dipping method in which a base body of each of the photoconductor drum and the collecting roller is dipped in a liquid in a state where the base body is in a vertical attitude such that a first end of the base body faces down and a second end of the base body faces up. The collecting roller is supported in a state where the first end of the collecting roller base body and the second end of the drum base body face a same direction.

Abstract: In a development device, a developer carrier arranged in a housing containing a one-component developer has a circumferential surface carrying the developer. A developer conveying path includes one conveying path along the developer carrier in a first direction and another conveying path in a second direction opposite to the first direction. The developer is circulated and conveyed between the conveying paths. A developer conveying member is arranged in the one conveying path and rotationally driven to convey the developer along the first direction and to supply the developer to the developer carrier. A layer thickness adjusting member is arranged at a distance from the circumferential surface to adjust a layer thickness of the developer supplied to the developer carrier. The developer carrier has a circumferential speed Vd and the developer conveying member has a circumferential speed Vs so that a circumferential speed ratio Vd/Vs satisfies a relationship represented by 1.3?Vd/Vs?5.0.