Ricoh Company, Ltd.

Saki Izumi

Hiroyuki Sugiyama

Kayoko Tanaka

Kohta Fujimori

Shunichi Hashimoto

Taichi Urayama

Ryusuke Mase

Mikio Ishibashi

Naoyuki Ozaki

Yuushi Hirayama

Hiroki Ishii

Hideaki Kanaya

An image forming apparatus includes an image bearer, a charging, a charge power supply to supply a charging bias to the charging device, a developing device, a toner adhesion amount detector, an environment detector, and a controller to determine whether to execute a charging bias adjustment process in which the charging device charges the image bearer to have different potentials, the developing device supplies the toner to the image bearer according to the different potentials, the toner adhesion amount detector detects the amount of toner adhering to the image bearer, and the controller adjusts the charging. The controller includes a memory device to store the environment data, and is configured to compare the environment data with previous environment data stored in the memory device, and determine not to execute the charging bias adjustment process when an environment change amount is not greater than a threshold.

Image forming apparatus and image forming system

An image forming apparatus includes a latent image bearer to rotate, an image forming unit including a charger and a developing device, a charge power supply to output a charging bias applied to a charger, a transfer device, a toner adhesion amount, and a controller. The controller causes the image forming unit to form a background fog pattern in a background area of the latent image bearer while changing a background potential, acquires toner adhesion amount values detected at different positions of the background fog pattern, having different potentials, sorts the toner adhesion amount values in an order of the background potential, determines a relation between the background potential and background fog amount based the toner adhesion amount values except any toner adhesion amount value out of monotonicity, and adjust the charging bias to an optimum value computed based on the determined relation.

Image forming apparatus and charging bias adjusting method therefor

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Ehime, Japan

Saki Izumi