Abstract: In the first charge amount acquisition operation, based on density of a plurality of toner images for measurement or based on a direct component of a developing current at the time of forming the plurality of toner images in addition to the density of the plurality of toner images for measurement, the charge amount acquisition section acquires a first toner charge amount that is a charge amount of toner included in the toner image for measurement. In the second charge amount acquisition operation, based on the toner density detected at the time of image formation and a relationship between the first toner charge amount and the toner density detected in the first charge amount acquisition operation, the charge amount acquisition section acquires a second toner charge amount that is a charge amount of the toner in the development device.

Abstract: An image forming apparatus has an image carrier, an electrifying member, and a charge eliminating device, and eliminates remaining charge on the surface of the image carrier by the charge eliminating device. The charge eliminating device includes a discharge member. The discharge member includes an electro conductive knit fabric knitted in a cylindrical shape using twisted yarn made of twisted metal fibers and a support member having a cylindrical shape and inserted in the electro conductive knit fabric, and is disposed to face the image carrier in a noncontact manner. A magnet member is disposed inside the image carrier within a charge elimination nip width between two tangential lines of an outer circumference surface of the discharge member, the two tangential lines being parallel to a straight line passing through a rotation center of the image carrier and a center axis of the discharge member.

Abstract: An image forming apparatus includes a storage unit and a charging amount acquisition unit. The charging amount acquisition unit forms a measurement toner image on the image carrier while changing the frequency of the alternating current voltage of the development bias, acquires a tilt of a measurement straight line representing a relationship between the change amount of the frequency and a density change amount of the measurement toner image based on the change amount of the frequency and a result of detecting density of the measurement toner image in the density detecting unit, and acquires the charging amount of the toner based on the acquired tilt of the measurement straight line and the reference information in the storage unit.

Abstract: A developing device includes a developing container, a first stirring and conveying member, a second stirring and conveying member, a developer replenishing port, a developer discharging portion, a developing roller, a toner supply roller, a regulating blade, a toner receiver member, and a vibration generating device. The developing device is capable of executing a toner collecting mode in which the vibration generating device vibrates the toner receiver member so that toner deposited on the toner receiver member is shaken off by vibration and is collected into the second conveying chamber, in the non-image formation period. The developing device is capable of executing a forced discharge mode in which developer containing the collected toner collected from the toner receiver member into the second conveying chamber is forcibly discharged from the developer discharging portion to outside of the developing container, after the toner collecting mode is executed.

Abstract: A developing device includes a developing container, a first stirring and conveying member, a second stirring and conveying member, a developer replenishing port, a developer discharging portion, a developing roller, a toner supply roller, a regulating blade, a toner receiver member, and a vibration generating device. The developing device is capable of executing a toner collecting mode in which the vibration generating device vibrates the toner receiver member so that toner deposited on the toner receiver member is shaken off by vibration and is collected into the second conveying chamber, in the non-image formation period. The developing device is capable of executing a forced discharge mode in which developer containing the collected toner collected from the toner receiver member into the second conveying chamber is forcibly discharged from the developer discharging portion to outside of the developing container, after the toner collecting mode is executed.

Abstract: In an image forming device including a volume supply type developing device, generation of an aggregate of a developer on a back surface of a layer thickness regulating member is suppressed, while occurrence of an image failure caused by the aggregate is suppressed. An image forming device includes: a photosensitive drum; a developing device including a developing roller; a toner container including a toner sensor; and a control portion. According to an increase or decrease of a retention part formed in a first transport path, a toner flows into the developing device from the toner container. The control portion causes the developing roller to reversely rotate at predetermined timing when the toner sensor senses that a residual amount of a toner in the toner container falls below a predetermined threshold value.

Abstract: An image forming apparatus has an image carrier, an electrifying member, and a charge eliminating device, and eliminates remaining charge on the surface of the image carrier by the charge eliminating device. The charge eliminating device includes a discharge member. The discharge member includes an electro conductive knit fabric knitted in a cylindrical shape using twisted yarn made of twisted metal fibers and a support member having a cylindrical shape and inserted in the electro conductive knit fabric, and is disposed to face the image carrier in a noncontact manner. A magnet member is disposed inside the image carrier within a charge elimination nip width between two tangential lines of an outer circumference surface of the discharge member, the two tangential lines being parallel to a straight line passing through a rotation center of the image carrier and a center axis of the discharge member.

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: In an image forming device including a volume supply type developing device, generation of an aggregate of a developer on a back surface of a layer thickness regulating member is suppressed, while occurrence of an image failure caused by the aggregate is suppressed. An image forming device includes: a photosensitive drum; a developing device including a developing roller; a toner container including a toner sensor; and a control portion. According to an increase or decrease of a retention part formed in a first transport path, a toner flows into the developing device from the toner container. The control portion causes the developing roller to reversely rotate at predetermined timing when the toner sensor senses that a residual amount of a toner in the toner container falls below a predetermined threshold value.

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 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 developing portion, a first rotation control portion, and a second rotation control portion. The developing portion has a conveying member configured to convey a developer within a circulation-conveyance passage, and a reducing portion provided in the conveying member and configured to reduce an ability to convey the developer. The first rotation control portion is configured to rotate the conveying member at a predetermined first speed when a printing process is executed. The second rotation control portion is configured to suspend execution of the printing process and rotate the conveying member at a second speed lower than the first speed, when an average coverage rate per page of a printed matter having a predetermined reference number of consecutively printed pages exceeds a predetermined threshold.

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 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 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: An image forming apparatus includes a developing portion, a first rotation control portion, and a second rotation control portion. The developing portion has a conveying member configured to convey a developer within a circulation-conveyance passage, and a reducing portion provided in the conveying member and configured to reduce an ability to convey the developer. The first rotation control portion is configured to rotate the conveying member at a predetermined first speed when a printing process is executed. The second rotation control portion is configured to suspend execution of the printing process and rotate the conveying member at a second speed lower than the first speed, when an average coverage rate per page of a printed matter having a predetermined reference number of consecutively printed pages exceeds a predetermined threshold.

Abstract: In the case where development is performed by a two-component developing method, a previous charge removal light-emitting portion applies charge removal light to a first charge removal target region of an effective outer circumferential surface of a photosensitive member on which effective outer circumferential surface an electrostatic latent image can be formed. The first charge removal target region includes a part of a magnetic brush contact region of the effective outer circumferential surface and a region of the effective outer circumferential surface between the magnetic brush contact region and a transfer position of a toner image.

Abstract: In the case where development is performed by a two-component developing method, a previous charge removal light-emitting portion applies charge removal light to a first charge removal target region of an effective outer circumferential surface of a photosensitive member on which effective outer circumferential surface an electrostatic latent image can be formed. The first charge removal target region includes a part of a magnetic brush contact region of the effective outer circumferential surface and a region of the effective outer circumferential surface between the magnetic brush contact region and a transfer position of a toner image.

Abstract: A developer storage container includes a container main body, a tubular portion projecting from the container main body, and a rotary member extending from the container main body to the tubular portion. The rotary member includes a first section located in the container main body and a second section located in the tubular portion. A first conveying member for conveying developer in a first conveying direction is arranged on the second section of a rotary shaft, and a second conveying member for conveying the developer in a second conveying direction is arranged radially outwardly of the first conveying member around the first section. A first flexible member radially extending to a side outward of the second conveying member and a second flexible member radially extending to a side outward of the second conveying member and having a shorter length than the first flexible member are mounted on the rotary shaft.