Ricoh Company, Ltd.

Tetsuya Muto

Shinichi Akatsu

Yuuichiroh Uematsu

Keita Gotoh

Akira Yoshida

Hitoshi Ishibashi

Shuji Hirai

Yushi Hirayama

Satoshi Kaneko

Shingo Suzuki

Nobutaka Takeuchi

Kohta Fujimori

Shin Hasegawa

Yoshiaki Miyashita

Tomohide Takenaka

Keita Sone

Kayoko Tanaka

Hitoshi Yamamoto

Masahiko Shakuto

Takamasa Ozeki

Mutsuki Morinaga

Keiko Kajimura

Naoto Watanabe

Junichi Matsumoto

Shinji Kato

Toshio Koike

Kiyonori Tsuda

Tadashi Kasai

Nobuo Takami

Yutaka Takahashi

Hideki Kosugi

Emiko Shiraishi

Makoto Yasuda

Nobuo Kuwabara

Takeroh Kurenuma

Akira Fujimori

Kunio Hasegawa

Kazuaki Kamihara

Hiroyuki Uenishi

Teppei Kikuchi

Ken Yoshida

Keiichi Yoshida

Keinosuke Kondoh

Tomoya Ohsugi

Jun Hitosugi

Hiroki Yamamura

Eichi Koizumi

Kentaro Mikuniya

Kazuhiro Aso

Kazufumi Kimura

Katsuya Akiba

Yu Takahashi

Yasuhito Shinchi

Kohhei Sakurada

Keita Goto

An image forming apparatus includes an image forming device to form an image on an image bearer and circuitry configured to accept, from a user, an input of a density level selected from a plurality of different density levels and control an image forming condition under which the image forming device forms the image. The circuitry is configured to correct density unevenness of the image formed on the image bearer by the image forming device and correct the density unevenness of the image at the density level accepted. The density unevenness is unevenness appearing in a main scanning direction orthogonal to a direction of conveyance of the image bearer during image formation.

Image forming apparatus for correcting density unevenness

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 a toner pattern bearer to bear a first toner pattern having a first image area and a second toner pattern having a second image area different from the first image area. A toner adhesion amount detector detects a toner adhesion amount of toner of each of the first toner pattern and the second toner pattern. A toner degradation rate calculator calculates a first deviation in the toner adhesion amount of the first toner pattern and a second deviation in the toner adhesion amount of the second toner pattern based on the toner adhesion amount detected by the toner adhesion amount detector. The toner degradation rate calculator compares the first deviation with the second deviation and calculates a toner degradation rate based on a comparison result.

Image forming apparatus and method for calculating a toner degradation rate

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 a developing device; a developer conveyance device including a developer container, a developer reservoir to receive developer discharged from the developer container, and a positive-displacement pump to discharge, from the developer reservoir, developer supplied to the developing device by alternately generating positive pressure and negative pressure due to volume changes; and a controller to control driving of the positive-displacement pump. When the controller recognizes a developer end state of the developer container, the controller lowers a developer conveyance capability of the positive-displacement pump from a setting used before the developer end state is recognized.

Developer conveyance device, image forming apparatus, and developer conveyance method

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 an image forming unit including rotary members to form a toner image corresponding to image data, in which the image forming unit forms a toner pattern for detecting image density fluctuation; and an image forming condition determination controller to perform image forming processing to ultimately transfer the toner image onto a recording medium. In the image forming apparatus, the controller measures a periodic image density fluctuation occurring in a rotation cycle of the rotary members based on a detection result of a toner pattern; performs image forming condition determination processing to determine an image forming condition to reduce the image density fluctuation based on measured image density fluctuation data; and determines whether or not the image density fluctuation data measured multiple times satisfies a predetermined control termination condition.

Image forming apparatus capable of effectively preventing image density fluctuation

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.

A toner supplying device including a secondary toner container, a first feeding member performing a first feeding operation of feeding toner from a toner container to the secondary container on demand, a second feeding member performing a second feeding operation of feeding the toner from the secondary container to a developing device on demand, and a toner supply controller controlling the amount of the toner in the secondary container to be greater than a predetermined amount. The controller performs first control in which when the first feeding operation is performed, the amount of the toner fed in the second feeding operation per unit of time is decreased, or second control in which when the amount of the toner fed in the second feeding operation is greater than a predetermined amount, the amount of the toner fed in the first feeding operation per unit of time is decreased.

Toner supplying device and image forming apparatus using same

An image forming apparatus includes: a charging unit that uniformly charges a surface of a latent image carrier; a latent-image forming unit; a developing unit that performs development by causing toner to electrostatically adhere on the surface of the carrier; a transfer unit that transfers a toner image onto a recording medium; and an image-density adjusting unit that causes to form a multi-gradation patch pattern on the surface of the carrier, that causes to detect potentials of latent image patches in the multi-gradation patch pattern, that causes to detect a toner adhesion amount on each toner patch, and that performs control of an image density. One of part and all of the low-density latent image patches is a dot-dispersed latent image patch in which the arrangement of unit dot latent images in the basic dot matrix is determined so that a minimum center-to-center distance having a smallest value is maximized.

An image forming apparatus includes a problem-occurrence determining unit, a problem-occurrence area determining unit, and a notifying unit. If the problem-occurrence determining unit determines that a problem has occurred in an image forming process, the problem-occurrence area determining unit determines whether the problem is caused by a toner filling process on the basis of toner-filling control data and toner-supply control data. The notifying unit then notifies the determination as to whether the problem is caused by the toner filling process.

Image forming apparatus having a first and second toner containers and a developing unit

An image forming apparatus forms a plurality of tone patterns of different colors, each of which containing a plurality of toner patches having different toner densities. Some of the toner patches in each of the tone patterns are formed with a predetermined fixed developing bias and the rest of the toner patches in each of the tone patterns are formed with developing biases set based on previous developing biases that have been obtained through a previous control process. The largest toner density of the toner patches in each of the tone patterns is determined based on a magnitude relation of previous index values obtained through the previous control process.

Image forming apparatus and image-density control method

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Kanagawa, Japan

Tetsuya Muto