Kyocera Document Solutions Inc.

Takeru Nagamoto

Minoru Wada

Ryo Taniguchi

Takahiro Okubo

Atsuya Ikeuchi

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 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&#x2212;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.

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Osaka, Japan

Takeru Nagamoto