Ricoh Company, Ltd.

Keita Gotoh

Tetsuya Muto

Yuuichiroh Uematsu

Shinichi Akatsu

Akira Yoshida

Satoshi Kaneko

Shingo Suzuki

Shuji Hirai

Tomohide Takenaka

Keita Sone

Hitoshi Yamamoto

Nobutaka Takeuchi

Hitoshi Ishibashi

Kohta Fujimori

Masahiko Shakuto

Kazuaki Kamihara

Takamasa Ozeki

Mutsuki Morinaga

Kazufumi Kimura

Keiko Kajimura

An image forming apparatus includes an image bearer, a toner image forming device, a plurality of image density detectors, and a controller. The plurality of image density detectors are disposed at predetermined intervals opposite the image bearer in a width direction of the image bearer. The controller causes the toner image forming device to form toner image patterns having an identical density at the plurality of positions on the image bearer and the plurality of image density detectors detects a density of the toner image patterns. Based on the detected density of the toner image patterns, the controller identifies multiple cyclic fluctuations of the density of the toner image patterns and adjusts an image forming condition based on the multiple cyclic fluctuations of the density of the toner image patterns to decrease an amplitude caused by the multiple cyclic fluctuations of the density of the toner image patterns.

Image forming apparatus and image forming method

An image forming apparatus includes an image bearer to bear a black toner pattern formed with a black toner image under an increased exposure amount and an increased developing bias. A first optical sensor detects an amount of reflection light reflected by the black toner pattern on the image bearer. The first optical sensor includes a light-emitting element to emit light toward the black toner pattern on the image bearer and a light-receiving element to receive the reflection light reflected by the black toner pattern on the image bearer. A toner adhesion amount converter converts the amount of the reflection light detected by the first optical sensor into a toner adhesion amount of toner adhered to the image bearer and adjusts an image density according to the toner adhesion amount.

Image forming apparatus having an optical sensor for converting a toner adhesion amount and image forming method

An image forming apparatus includes an image bearing belt of a multi-layer structure, a toner image forming device, a nip forming device, a transfer power source, an environment-condition detector, and a controller. The toner image forming device forms a toner image on a surface of the image bearing belt. The transfer power source outputs a transfer bias including a superimposed voltage, in which a direct current voltage is superimposed on an alternating current voltage to transfer the toner image from the image bearing belt onto a recording medium at a transfer nip. The environment-condition detector detects an environment condition. The controller controls the transfer bias output from the transfer power source to perform a bias switching process to switch the transfer bias between a transfer bias including the superimposed voltage and a transfer bias including a direct current voltage based on a detected result of the environment-condition detector.

Image forming apparatus that switches transfer bias based on detected environment condition

An image forming apparatus includes an endless belt-shaped image bearer that is rotatably supported and entrained around rollers; a transfer member positioned to contact an outer surface of the image bearer; a transfer device to transfer a toner image conveyed while being carried on the outer surface of the image bearer onto a transfer medium conveyed between the image bearer and the transfer member; a toner image sensor to detect the toner image transferred onto the transfer medium; and a conveyance speed controller to fine-tune a conveyance speed of the transfer medium. Based on fine-tuning data of the conveyance speed controller, a detection result of the toner image sensor is corrected and image forming conditions are corrected based on the corrected detection result.

Toner pattern density correction in an image forming apparatus

An image forming apparatus includes an image bearer; a charger to charge the image bearer; an electrostatic latent image former to form an electrostatic latent image on the image bearer; an image developer to develop the electrostatic latent image with a toner to form a visual toner image; a transferer to transfer the toner image on a transfer material; a toner concentration calculator to calculate a concentration of the toner; and an optical detector. At least a toner patch image is formed on the image bearer with an irradiation quantity set such that an irradiated part potential is larger than a developing condition, the toner patch image is read by the optical detector, and the charging condition is corrected on the basis of a difference between a toner concentration of the toner patch image and a target toner concentration.

Image forming apparatus and image density control

An image forming apparatus includes an image density detector, an image forming device, a rotator, an image density controller, and a timing correction data obtainer. The image density detector detects a toner density of an image formed on an image bearing member. An image forming device forms the image using a density adjustable element that adjusts the density of the image. The rotator forms an image pattern while the density adjustable element is changed, and a density thereof is detected by the image density detector. The image density controller controls the image forming device using a density correction data for the density adjustable element corresponding to a rotational period of the rotator. The timing correction data obtainer obtains timing correction data for correction of driving timing of the image forming device based on a change in the density of the image pattern detected by the image density detector.

An image forming apparatus includes an image carrier, a rotation-position detector, a development device, a transfer unit, a density sensor, and an image-forming-condition determination unit. The density sensor senses a density of a toner image on a transfer body. The image-forming-condition determination unit forms an image pattern, acquires periodical density variation information sensed by the density sensor and detection information of the rotation-position detector, and determines an image forming condition based on the periodical density variation information and the detection information acquired. The image carrier and the transfer body are different in linear velocity in an image formation in which the toner image is transferred to a recording medium. The image carrier and the transfer body are controlled to be equal in linear velocity in an information acquisition in which the image-forming-condition determination unit acquires the periodical density variation information and the detection information.

Image forming apparatus

An image forming apparatus includes a latent-image bearing body, a charging unit, a latent-image writing unit, a development unit, a development power, and a bias control unit. After a start of an image forming operation, the bias control unit performs a process of constantly maintaining an output of a development bias at an adjustment bias value. The adjustment bias value is a central value in a periodic fluctuation range of the output of the development bias. At a timing at which a difference of the development bias from the adjustment bias value in the periodic fluctuation range is less than or equal to a predetermined threshold value, the bias control unit performs switching from the process of constantly maintaining the output of the development bias at the adjustment bias value to a process of periodically changing the output of the development bias based on development bias control data.

Growing community of inventors

Kanagawa, Japan

Keita Gotoh