Abstract: A toner supply device for supplying toner to a developing device includes a toner container containing toner to be supplied to the developing device and a remaining amount sensor for detecting the remaining amount of toner in the toner container. The toner container includes a cylindrical rotating container having a spiral conveying rib formed on the inner peripheral surface thereof and a paddle provided so as to be slidable on the inner peripheral surface of the rotating container. The remaining amount sensor detects the remaining amount of toner on the upstream side on or before the contact position of the paddle in the toner conveying direction.

Abstract: A meniscus lens has a dome shape and has a first surface facing a lens array and a second surface facing an infrared sensing element. The meniscus lens has a central portion and a peripheral portion. The central portion includes a top point that is an intersection between the optical axis of the meniscus lens and the first surface. The peripheral portion includes an end of the first surface of the meniscus lens. With respect to the central portion of the meniscus lens, an aplanatic point of the first surface is located at the focus of the lens array. With respect to the peripheral portion of the meniscus lens, an aplanatic point of the second surface is located at the focus of the lens array.

Abstract: A toner supply device for supplying toner to a developing device includes a toner container containing toner to be supplied to the developing device and a remaining amount sensor for detecting the remaining amount of toner in the toner container. The toner container includes a cylindrical rotating container having a spiral conveying rib formed on the inner peripheral surface thereof and a paddle provided so as to be slidable on the inner peripheral surface of the rotating container. The remaining amount sensor detects the remaining amount of toner on the upstream side on or before the contact position of the paddle in the toner conveying direction.

Abstract: A charging device includes a charging roller, a cleaning roller, a pair of first supporting members, a pair of second supporting members and a pair of elastic members. The pair of first supporting members supports the charging roller in a rotatable manner. The pair of second supporting members supports the cleaning roller in a rotatable manner. The pair of elastic members is disposed between the first supporting members and the second supporting members, and pushes back the cleaning roller in a direction separate away from the charging roller. The second supporting member provided on one side in an axial direction of the cleaning roller has a roller-shift preventing part which blocks the cleaning roller. The elastic member provided on the one side in the axial direction pushes back the cleaning roller with force smaller than force of the elastic member provided on the other side in the axial direction.

Abstract: An image forming apparatus includes: an image forming portion having an image carrying member, a charging device, an exposing device, and a developing device; a developing voltage power supply; a control portion; and an image density sensor. The developing device has a developer carrying member that carries two-component developer and a toner concentration sensor. The control portion senses toner concentration during calibration or during first image formation after calibration for correcting image density based on the sensing result from the image density sensor. If the difference Vtarget?V between the output value V of the toner concentration sensor actually sensed and a target value Vtarget of the toner concentration sensor to be observed when the toner concentration equals a reference concentration is equal to or larger than a predetermined value, the control portion performs calibration again when the amount of toner consumed after calibration reaches a predetermined threshold value.

Abstract: A meniscus lens has a dome shape and has a first surface facing a lens array and a second surface facing an infrared sensing element. The meniscus lens has a central portion and a peripheral portion. The central portion includes a top point that is an intersection between the optical axis of the meniscus lens and the first surface. The peripheral portion includes an end of the first surface of the meniscus lens. With respect to the central portion of the meniscus lens, an aplanatic point of the first surface is located at the focus of the lens array. With respect to the peripheral portion of the meniscus lens, an aplanatic point of the second surface is located at the focus of the lens array.

Abstract: An image forming apparatus includes: an image forming portion having an image carrying member, a charging device, an exposing device, and a developing device; a developing voltage power supply; a control portion; and an image density sensor. The developing device has a developer carrying member that carries two-component developer and a toner concentration sensor. The control portion senses toner concentration during calibration or during first image formation after calibration for correcting image density based on the sensing result from the image density sensor. If the difference Vtarget?V between the output value V of the toner concentration sensor actually sensed and a target value Vtarget of the toner concentration sensor to be observed when the toner concentration equals a reference concentration is equal to or larger than a predetermined value, the control portion performs calibration again when the amount of toner consumed after calibration reaches a predetermined threshold value.

Abstract: A charging device includes a charging roller, a cleaning roller, a pair of first supporting members, a pair of second supporting members and a pair of elastic members. The pair of first supporting members supports the charging roller in a rotatable manner. The pair of second supporting members supports the cleaning roller in a rotatable manner. The pair of elastic members is disposed between the first supporting members and the second supporting members, and pushes back the cleaning roller in a direction separate away from the charging roller. The second supporting member provided on one side in an axial direction of the cleaning roller has a roller-shift preventing part which blocks the cleaning roller. The elastic member provided on the one side in the axial direction pushes back the cleaning roller with force smaller than force of the elastic member provided on the other side in the axial direction.

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 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: An image forming apparatus includes an image carrier, a developing roller, and a control unit. The image carrier has a surface on which an electrostatic latent image is formed. The developing roller is arranged to face the image carrier to form a development nip between the image carrier and the developing roller. The developing roller supplies toner in a two-component developer carried on a surface of the developing roller to the image carrier in the development nip so as to develop the electrostatic latent image. The control unit drivingly controls the image carrier and the developing roller. The control unit discharges the toner in the development nip to the image carrier in a state where the developing roller is stopped, so as to calculate a toner concentration in the two-component developer based on an amount of discharged toner.

Abstract: A developing device includes a housing, a developer carrier, a conveying member and a surface layer. The conveying member conveys the developer in the first conveying direction and supplies the developer to the developer carrier. The surface layer is arranged on the circumferential surface of the developer carrier and formed on a surface of a predetermined cylindrical base member. The surface layer is formed by an immersion method of immersing the base member in an immersion tank so that an axial direction of the base member extends along a vertical direction. A lower end side of the base member at the time of the immersion is arranged in a downstream side of the housing in the first conveying direction and an upper end side of the base member at the time of the immersion is arranged in an upstream side of the housing in the first conveying direction.

Abstract: In a developing device, a developing coating layer of each of a plurality of developing rollers has been formed by a dipping method in which a developing base body is dipped in a liquid in a state where the developing base body is in a vertical attitude such that a first end of the developing base body faces down and a second end of the developing base body faces up. The plurality of developing rollers are arranged from an upstream side to a downstream side in a rotation direction of an image-carrying member in such a manner that directions faced by the first end and the second end of each of the plurality of developing rollers are alternately reversed.

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.