Ricoh Company, Ltd.

Kohta Fujimori

Kayoko Tanaka

Shin Hasegawa

Nobutaka Takeuchi

Hitoshi Ishibashi

Yushi Hirayama

Shinji Kato

Kazumi Kobayashi

Takashi Enami

Naoto Watanabe

Akira Yoshida

Shinji Kobayashi

Fukutoshi Uchida

Osamu Ariizumi

Ryohta Morimoto

Yoshiaki Miyashita

Shuji Hirai

Kentaroh Tomita

Kiichirou Shimizu

Noboru Sawayama

Tetsuya Muto

Keita Sone

Yuushi Hirayama

Akio Kosuge

Natsumi Matsue

Satoru Komatsubara

Yuuichiroh Uematsu

Kazufumi Kimura

Hiroyuki Sugiyama

Yoshio Hattori

Shunichi Hashimoto

Takeroh Kurenuma

Hiroyuki Uenishi

Shinichi Akatsu

Keiichi Yoshida

Mikio Ishibashi

Keiko Matsumoto

Naoyuki Ozaki

Tomohide Takenaka

Yoichi Sakurai

Yuji Hirayama

Keita Gotoh

Hideki Kamaji

Kayoko Ikegami

Saki Izumi

Chiemi Hirano

An image forming apparatus includes an image bearer, an image forming device to form a toner image on the image bearer, a transfer device to transfer the toner image to a recording medium, a line sensor as an image density sensor to detect image density of the toner image, and a controller operatively connected to the image density sensor. The image density sensor is disposed so as to be shorter in a rotational direction of the image bearer than in a width direction of the image bearer perpendicular to the rotational direction of the image bearer. The controller forms a shading pattern image including a plurality of patches on the image bearer, and detects image density of the plurality of patches, so as to control image density. The shading pattern image is shorter in the rotational direction of the image bearer than in the width direction of the image bearer.

Image forming apparatus incorporating line sensor

An image forming apparatus includes an image bearer that bears a toner image, a sensor, an adhesion amount calculator, and a wavelength determiner. The sensor includes a light source that emit light onto the image bearer, and an image element that detects reflected light that is emitted from the light source and reflected from the image bearer. The adhesion amount calculator calculates a toner adhesion amount of the toner image on the image bearer based on the reflected light having at least one wavelength among a plurality of wavelengths detected by the sensor. The wavelength determiner determines, based on color information of the image bearer detected by the sensor, a wavelength to be used in calculation of the toner adhesion amount by the adhesion amount calculator.

Image forming apparatus and control method for image forming apparatus

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

An image forming apparatus includes a developer bearer and a toner pattern bearer rotatable in a given direction of rotation to bear an adjustment toner pattern formed with the developer bearer. A toner pattern detector detects an amount of reflection light reflected by the adjustment toner pattern on the toner pattern bearer. A controller performs an adjustment mode to convert the detected amount of reflection light into a toner adhesion amount of toner of the adjustment toner pattern adhered to the toner pattern bearer. The controller forms an adhesion amount suppressing toner image on an upstream region on the toner pattern bearer that is upstream from the adjustment toner pattern in the direction of rotation of the toner pattern bearer. The upstream region is defined by a circumferential length of the developer bearer in the direction of rotation of the toner pattern bearer.

Image forming apparatus and image forming method

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 image forming unit; an image bearing member having a surface to bear a toner image and a test pattern; the surface having a first time-surface positioned identical to the test pattern, an integer multiple of revolutions upstream or downstream from the test pattern in a surface movement direction, and a second time-surface positioned different from the test pattern, shorter than one revolution upstream or downstream from the test pattern; a reflection light detector to detect the amount of light reflected from the test pattern and the first and second time-surfaces of the image bearing member; and a controller to control the image forming unit based on the detection result and determine whether to execute a first-surface control to detect at least the first time-surface or a second-surface control to detect only the second time-surface based on use condition of the image forming apparatus.

Image forming apparatus capable of determining a toner adhesion quantity

In an image forming apparatus, a processor performs: a solid density stabilization of adjusting, in accordance with detected toner adhesion amounts of solid toner images of solid tone patterns, a condition to form solid images with respective target image densities; a misregistration reduction of adjusting, in accordance with detection timing of position detection toner images of misregistration detection patterns, a condition to reduce misregistration of toner images; and a halftone density stabilization of adjusting, in accordance with detected toner adhesion amounts of area coverage modulation toner images, a condition to form halftone images with respective target image densities. The processor continuously performs the solid density stabilization and the misregistration reduction, and starts the halftone density stabilization when the solid density stabilization is completed and the misregistration reduction is not completed, to concurrently perform a step of the misregistration reduction and at least a step of the halftone density stabilization.

An image forming apparatus includes a controller configured to control a toner-image forming device to form a toner patch; and a detector configured to detect the toner patch on the image carrier. During a non-printing period, the controller causes a toner-image forming device to form toner patches, causes the detector to detect densities of the toner patches, and adjusts an image-forming condition of the toner-image forming device based on detected densities. During a printing period, the controller causes the toner-image forming device to form an output image in an image area and form fewer toner patches in a non-image area, causes the detector to detect densities of the fewer toner patches, and adjusts the image-forming condition of the toner-image forming device based on detected densities. The fewer toner patches are selected from and fewer than the plurality of toner patches formed during the non-printing period.

Image forming apparatus using a plurality of toner patches during a non-printing period

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 developer unit to store two-component developer which includes toner and carrier and develop an electrostatic latent image formed on the image carrier, a toner concentration detector to detect toner concentration in the developer unit, a toner supply unit to supply toner to the developer unit, and a controller to control toner supply amount by controlling the toner supply unit by comparing an output value of the toner concentration detector with a reference value stored in a memory and correcting difference between output values of the toner concentration detector at two or more process linear velocities in accordance with the toner concentration in the developer unit. A compensation amount for correcting difference between output values of the toner concentration detector that differ depending on the process linear velocity is adjustable in accordance with the toner concentration in the development unit.

Image forming apparatus and method for controlling image density

An optical sensor includes: a light-emitting unit; a light-receiving unit that receives light radiated from the light-emitting unit and reflected from a detection target and that outputs an output value in response to the light received; and a correcting unit that corrects the output value of the light-receiving unit when receiving the light reflected from the detection target based on the output value of the light-receiving unit obtained by irradiating a detection area of the optical sensor with light without any light reflective objects being present in the detection area.

Optical sensor and image forming apparatus

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

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Kanagawa, Japan

Kohta Fujimori