Kyocera Document Solutions Inc.

Takahiro Okubo

Tamotsu Shimizu

Kazuhiro Nakachi

Mitsuhiro Hashimoto

Minoru Wada

Shiro Kaneko

Yohei Wakasa

Akihiro Watanabe

Norio Kubo

Ryo Taniguchi

Eiji Gyotoku

Yasushi Imanishi

Takeru Nagamoto

An image forming apparatus includes an image carrying member, a charging device, an exposure device, a developing device, a development voltage power supply, and a control section. The developing device includes a development container which contains a non-magnetic one-component developer and a developer carrying member which includes a rotary shaft and a roller portion stacked on the outer circumferential surface of the rotary shaft, and the resistance value of the roller portion is 9 to 11 [Log Ω], and when the amount of toner conveyed on the developer carrying member is Md [g/m], the amount of toner adhered on the image carrying member in a solid image is Mp [g/m], the peripheral speed of the developer carrying member and the image carrying member are Sd [mm/sec] and Sp [mm/sec], 0.8×Sd/Sp<Mp/Md and 0.8≤Sd/Sp≤1.2 are satisfied.

Image forming apparatus

An image forming apparatus includes an image forming unit, a toner detection sensor, a storage unit, and a control unit. The image forming unit includes an image carrier, a charging device, an exposure device, and a developing device. The toner detection sensor detects toner in the developing device. The control unit predicts transition of the toner deterioration degree in the developing device using the toner consumption amount and the cumulative operating time stored in the storage unit, and a predetermined toner deterioration model. The control unit is capable of measuring the toner deterioration degree based on amplitude of an output value of the toner detection sensor, and corrects the toner deterioration model, if the measured value of the toner deterioration degree is apart from the predicted value of the toner deterioration degree by a predetermined value or more.

Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. The developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. The density detecting device detects the density of the toner image. The current detecting unit detects a DC component of a developing current that flows when a developing voltage is applied to the developer carrier. The control unit, in a state in which the image carrier is rotated at two or more different linear speeds during non-image formation, forms the same reference image on the image carrier by the developing device, and estimates the toner charge amount based on the developing current when the reference image is formed and the density of the reference image.

Image forming apparatus using two-component developer including toner and carrier that determines toner charge amount based on a developing current

Provided is an image forming apparatus having a simple configuration capable of measuring a toner current included in a developing current and accurately calculating a toner charge amount based on the measurement result. A developing device has a developer carrier that carries a two-component developer including a magnetic carrier and toner. A developing voltage power supply applies a developing voltage obtained by superimposing an AC voltage on a DC voltage on the developer carrier. A control unit estimates a toner charge amount based on a toner current calculated by subtracting a carrier current from a developing current detected by a current detecting unit when a reference image is formed during non-image formation, and a toner developing amount calculated from the density of a reference image detected by a density detecting device.

Image forming apparatus having simple configuration and capable of measuring toner current included in developing current, and accurately calculating toner charge amount based on measurement result

An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a two-component developer. The control portion can perform a transfer memory prediction mode that includes a step of estimating, when a first reference image is formed, the level of occurrence of transfer memory based on the direct-current component of a development current flowing through the developer carrying member and a step of measuring, when the measured direct-current component of the development current is larger than a predetermined value, the amount of charge of the toner within the developing device and estimating the cause of occurrence of the transfer memory based on the measured amount of charge of the toner.

Image forming apparatus capable of predicting the level of occurrence of a transfer memory and the cause of occurrence thereof

An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a developer including a carrier and a toner. The control portion can perform a development ghost prediction mode that includes a step of measuring the amount of charge of the toner within the developing device at the time of non-image formation, a step of measuring, as a carrier current, the direct-current component of a development current when the amount of development of the toner is 0 [mg/cm] and a step of estimating the level of occurrence of development ghost and the cause of occurrence based on the amount of charge of the toner and the carrier current which are measured.

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.

Developing device and image forming apparatus provided with same

An image forming apparatus has an image carrier, a charger, a developing device, a voltage application unit, and a controller. The developing device includes a developing roller. The voltage application unit applies a voltage to the developing roller and to the charger. The controller controls the voltage application unit. The controller controls the voltage application unit such that a developing bias having an AC voltage superposed on a DC voltage is applied to the developing roller and a charging bias including at least a DC voltage and having superposed thereon a compensation AC voltage with an opposite phase to an AC voltage induced in the charger by the developing bias is applied to the charger.

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Osaka, Japan

Takahiro Okubo