Ricoh Company, Ltd.

Hitoshi Ishibashi

Kohta Fujimori

Yushi Hirayama

Shin Hasegawa

Kayoko Tanaka

Nobutaka Takeuchi

Shinji Kato

Naoto Watanabe

Shinji Kobayashi

Kazumi Kobayashi

Takashi Enami

Fukutoshi Uchida

Shuji Hirai

Masumi Sato

Osamu Ariizumi

Ryohta Morimoto

Akira Yoshida

Yukiko Iwasaki

Takatsugu Fujishiro

Noboru Sawayama

Tetsuya Muto

Kentaroh Tomita

Hiroshi Yoshinaga

Satoshi Kaneko

Masami Hiramatsu

Shingo Suzuki

Yoshiaki Miyashita

Koichi Kudo

Akio Kosuge

Jun Yamane

Yuushi Hirayama

Hiroko Hirano

Yuuji Sawai

Atsushi Takehara

Takayuki Maruta

Takahiro Yoshikawa

Satoru Komatsubara

Megumi Ohtoshi

Hideo Muroi

Yuji Arai

Hiroshi Ono

Masami Tomita

Toshio Koike

Satoshi Takano

Tatsuya Niimi

Kiyonori Tsuda

Ken Amemiya

Koichi Sakata

Masanori Kawasumi

Yasufumi Takahashi

Koichi Kato

Yuki Oshikawa

Takeroh Kurenuma

Haruji Mizuishi

Kohichi Utsunomiya

Hiroyuki Uenishi

Shinichi Akatsu

Keiichi Yoshida

Mugijirou Uno

Hisao Murayama

Itaru Matsuda

Keiko Matsumoto

Takuzi Yoneda

Yuuichiroh Uematsu

Yoshinori Ozawa

Tokuya Ohjimi

Yuko Harasawa

Eichi Koizumi

Keita Gotoh

Eriko Maruyama

Hideki Kamaji

Kayoko Ikegami

Hiroshi Yosinaga

Masumi Satou

Megumi Otoshi

Chiemi Hirano

An image forming apparatus includes an image carrier; a developer carrier configured to adhere toner onto the image carrier; an image density detector to detect a density of an image on the image carrier formed by the developer carrier adhering the toner on the image carrier; a rotary member to form an image pattern of which density is detected by the image density detector; and a rotational position detector to detect a rotational position of the rotary member. In the image forming apparatus, the image pattern is generated based on the rotational position detected by the rotational position detector and the rotary member that the rotational position detector detects the rotational position thereof is either the image carrier or the developer carrier.

Image forming apparatus and image forming method

In an image forming apparatus, a processor generates a first density variation data based on the surface potential of the pattern in relation to the rotational position of the image bearer and a second density variation data based on the first density variation data and the density of the toner pattern, stores the first density variation data and the second density variation data in a memory, makes a pattern in a predetermined timing, decides whether the first density variation data is changed or not, change the first density variation data based on the decision, controls the toner image forming condition of the toner image forming device based on the first density variation data and the second density variation data.

Image forming apparatus capable of reducing image density irregularity

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 a rotatable image carrier that carries a toner image having a length corresponding to at least a circumferential length of the carrier; an image density detector that detects a density of the image; a potential detector that detects, over at least the circumferential length, a surface potential of the carrier before toner adheres thereto; a first image forming device that adjusts the density with a first factor, and forms an image based on a first condition of the first factor; a second image forming device that adjusts the density with a second factor, and forms an image based on a second condition of the second factor; a first determining device that determines the first condition based on uneven density; and a second determining device that determines the second condition based on uneven density and a potential distribution of the surface potential.

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

In an embodiment, a diffuse reflection output conversion method is executed in an apparatus detecting a plurality of gradation patterns. The apparatus includes a light emitter and light receiver, and detects specular reflection and diffuse reflection simultaneously. A region before specular reflection saturation is a region where the specular reflection component decreases and saturates at minimum level. A diffuse reflection detector is calibrated by: obtaining a diffuse reflection output resulting from an amount of attached powder at a border between the region before specular reflection saturation and the region after specular reflection saturation; calculating a ratio between the diffuse reflection output and a reference diffuse reflection output calculated in advance as a calibration coefficient; and multiplying a diffuse reflection output obtained from the gradation patterns by the calibration coefficient calculated at the calculating.

Diffuse reflection output conversion method, attached powder amount conversion method, and image forming apparatus

A developing device for developing an electrostatic latent image on an image bearing member including a developer bearing member opposed to the image bearing member to bear thereon a developer including a toner and a magnetic carrier; a developer containing part to contain the developer to supply the developer to the developer bearing member; an agitating or feeding member to agitate or feed the developer in the developer containing part; a magnetic permeability sensor to measure magnetic permeability of the developer to determine toner concentration of the developer; a developer feeder; a feeding member to feed the developer to the developer containing part through the developer feeder; and a driver to drive the feeding member independently of the agitating or feeding member. The magnetic permeability sensor is arranged on the developer feeder.

Developing device and image forming apparatus

An optical sensor attached to an apparatus includes a substrate and a light emitting element mounted on a first surface of the substrate. The light emitting element emits a light to a detection object in parallel to the substrate. A light receiving element is mounted on the first surface of the substrate. The light receiving element receives a regular reflection light reflected by the detection object. The said first surface serves as a positioning reference for positioning the optical sensor on an optical sensor mounting member provided in the apparatus.

Optical sensor with positioning reference surface and image forming apparatus incorporating optical sensor

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

In a color misalignment detection method, an alignment pattern is obtained by designating a plurality of lines having line width and line intervals formed by superposing a line image of a black color as a reference color and a line image of a color other than the reference color, for example, a cyan line image, as one patch, and continuously forming these patches by shifting the relative position between the line images of the two colors by an optional quantity. An alignment pattern detection sensor has a light emitting diode and a photodiode. These elements are arranged along the scanning direction of the alignment pattern such that the photodiode can only receive diffused reflected light of reflected light from the alignment pattern. A spot shape of the light emitting diode and a spot shape of the photodiode are both formed in a square shape.

Color image formation apparatus for forming a reference pattern with a plurality of lines having a black color as reference color and for correcting misalignment with respect to the reference pattern

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

An image forming apparatus is disclosed that includes an image density control unit that performs control operations based on an image density control condition that is adjustably set to control an output image to have a predetermined image density, an image density control condition modifying unit that calculates a modified image density control condition based on information on an amount of toner exchanged at a developing apparatus within a predetermined period and a parameter for image density control condition calculation and sets the modified image density control condition as the image density control condition to be used by the image density control unit, and a parameter modifying unit that modifies the parameter for image density control condition calculation used by the image density control condition modifying unit based on a toner pattern detection result obtained by detecting a toner pattern formed on a belt member.

Image forming apparatus and image density control method

An image forming apparatus includes an image carrying member, an image forming mechanism, an optical sensor, and a controller. The image forming mechanism performs an image forming operation for forming a reference toner image on the image carrying member under a specific setting associated with the image forming mechanism. The optical sensor is arranged in a vicinity to the image carrying member. The controller performs an optical toner test for checking, by using the optical sensor, optical characteristics of the reference toner image formed on the image carrying member and to adjust the specific setting based on a result of the optical toner test.

Image forming apparatus capable of reducing a lengthy duration of an adjustment control

A process cartridge for use in an image forming apparatus includes an image bearing member and a developing unit. The developing unit includes a developer bearing member to bear developer including toner and carrier, a casing forming a developer container containing the developer, a screw having a shaft with a spiral screw blade, a toner density sensor to detect a density of the toner on a detection surface, and a detection surface agitating member fixedly mounted on the shaft of the screw at a position facing a detection surface to scrape away the developer accumulated on the detection surface as the screw rotates. The detection surface agitating member includes an elastic sheet elastically deformable to scrape away the developer accumulated on the detection surface and disposed at a substantially same angle to an axial direction of the shaft of the screw as the spiral screw blade.

Process cartridge including developing unit and incorporated in image forming apparatus

An image forming apparatus includes an image carrier configured to carry an image and a charger to which a direct current voltage overlapped with an AC voltage is applied as a charging bias to charge the image carrier. The charger is positioned in contact or contactlessly with the image carrier. The AC voltage applied to the charger in an adjustment of the AC voltage is not less than twice a charging start voltage Vth at which the image carrier starts to be charged.

Image forming apparatus and method of adjusting charge bias

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Kanagawa, Japan

Hitoshi Ishibashi