Ricoh Company, Ltd.

Tomohide Takenaka

Keita Sone

Masayoshi Nakayama

Shinichi Akatsu

Masashi Tachi

Kazuaki Kamihara

Tetsuya Muto

Masaki Sukesako

Yuuichiroh Uematsu

Takuma Higa

Keita Gotoh

Akira Yoshida

Yuichi Aizawa

Shinya Tanaka

Daisuke Ito

Daisuke Takahashi

Hitoshi Yamamoto

Nobutaka Takeuchi

Kohta Fujimori

Masahiko Shakuto

Takamasa Ozeki

Ken Yoshida

Keiko Matsumoto

Kohei Matsumoto

Mutsuki Morinaga

Yoichi Sakurai

Naoki Ohta

Yoshiaki Morita

Kazufumi Kimura

Masahiro Katoh

Keiko Kajimura

Sohichiroh Ishikawa

An image forming apparatus includes an image former, a detector, and circuitry. The image former forms a toner pattern with a first line screen; and forms a toner image based on image data, with a second line screen. The detector detects density unevenness of the toner pattern, formed by the image former, in a main scanning direction. The circuitry is configured to calculate a first correction amount from the density unevenness detected by the detector; create a gradation correction table that reduces the density unevenness based on the first correction amount; and correct the first correction amount by a second correction amount corresponding to the second line screen, in a case where the first line screen is different from the second line screen.

Image forming apparatus

An image forming apparatus includes a plurality of image forming units, an exposure device, and circuitry. Each image forming unit includes an image bearer, a charger, and a developer bearer. The circuitry acquires an image-density cycle fluctuation in a visible image for each image forming unit and performs image-density fluctuation-reduction control to cyclically change image forming conditions to reduce the image-density cycle fluctuation. The circuitry performs: first fluctuation-reduction control to correct a developing bias to cancel an image-density cycle fluctuation of a high-density image pattern; second fluctuation-reduction control to, after the first fluctuation-reduction control, correct a charging bias to cancel an image-density cycle fluctuation of a first low-density image pattern; and third fluctuation-reduction control to, after the first and second fluctuation-reduction controls, correct an exposure light amount to cancel an image-density cycle fluctuation of a second low-density image pattern.

Image forming apparatus to perform phase matching control to match phases of image-density cycle fluctuations

The present invention pertains to an image forming apparatus that includes a latent image bearer, an exposure device, a detector, and processing circuitry. The exposure device exposes the latent image bearer to form a latent image based on image data. The detector detects density unevenness, in a main scanning direction, of a toner image obtained by developing the latent image. The processing circuitry corrects only an exposure amount of the exposure device based on the density unevenness to form an image portion with a higher gradation than a prescribed gradation, the processing circuitry further configured to correct the exposure amount and the image data based on the density unevenness in the main scanning direction detected by the detector to form an image portion with a gradation equal to or lower than the prescribed gradation.

Image forming and correction apparatus

An image forming apparatus includes an image forming device, a density deviation detector, and processing circuitry. The circuitry performs a density deviation adjustment mode to: cause the image forming device to form a first image pattern having a uniform image density in the width direction on a surface of an image bearer; cause the detector to detect a first image density deviation in the width direction in the first pattern; adjust the first deviation based on a detection result of the first pattern; cause the image forming device to form a second image pattern on a surface of the image bearer after adjustment of the first deviation; cause the detector to detect a second image density deviation in the width direction in the second pattern; and correct a light intensity sensitivity in adjusting the second deviation, based on a detection result of the second pattern.

Image forming apparatus and image formation method

An image forming apparatus includes a latent image bearer to bear a latent image, a potential sensor having a vibrator driven by a drive frequency to detect a surface potential of the latent image bearer, a developer bearer to bear developer that develops the latent image on the latent image bearer, and a power supply to apply a superimposed voltage obtained by superimposing an alternating voltage on a direct current voltage on the developer bearer. The frequency of the alternating voltage is not a multiple of the drive frequency and is a value obtained by adding a predetermined value to a multiple of the driving frequency.

Image forming apparatus and voltage application method

An electrophotographic image forming apparatus includes a latent image bearer to rotate and bear a latent image, a charging device to charge the a latent image bearer, a developing device to develop the latent image with developer including toner and use a developing voltage including an AC component, and a lubricant applicator to apply lubricant onto a surface of the latent image bearer. An amount of the lubricant applied by the lubricant applicator onto the latent image bearer per centimeter in an axial direction of the latent image bearer is equal to or greater than 0.845 mg for a running distance of 1.0 kilometer of the latent image bearer, and a difference between a largest value and a smallest value of the developing voltage is in a range of 200 V to 400 V.

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 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 a latent image bearer; a charger; an exposure device; a developing device; a potential detector to detect a surface potential at a detection position between an exposure position and a development position on the latent image bearer in a direction of rotation of the latent image bearer; and a potential controller to determine an image forming condition. The potential controller includes a potential calculator to calculate an exposed area potential based on a detected potential smaller in charging polarity than a potential threshold, out of the detected surface potential, and a threshold determiner to set the potential threshold between the exposed area potential and an unexposed area potential of the latent image bearer based on at least one of a change in the unexposed area potential, a change with time of the latent image bearer, and a change in an ambient condition.

Image forming apparatus which sets image forming condition based on calculated exposed area potential

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 carrier, a transfer unit, and a control unit. The image carrier has a surface to bear a toner image thereon. The transfer unit has a transfer member to transfer the toner image onto a recording sheet conveyed in a conveyance direction for trailing-end borderless image formation and duplex image formation. The transfer unit is configured to form the toner image on the recording sheet without forming a margin at a trailing end of the recording sheet in the conveyance sheet in the trailing-end borderless image formation. The transfer unit is configured to form the toner image on front and back faces of the recording sheet in the duplex image formation. When a width of the toner image formed in a borderless image area of the recording sheet in the trailing-end borderless image formation is smaller in a direction perpendicular to the conveyance direction than a threshold value, the control unit permits the duplex image formation. When the width is the threshold value or greater, the control unit prohibits the duplex image formation.

In a RAM are stored a first deflection information table representing the relationship between the rotation amount and the deflection amount of a photosensitive element, a second deflection information table representing the relationship between the rotation amount and the deflection amount of a developing sleeve, a writing sensitivity information table representing the relationship between the rotation amount of the photosensitive element and latent image writing sensitivity, and an image forming condition information table representing the relationship between the rotation amount and laser power. An information input unit is provided to input the respective tables. During a print job, laser power is changed on the basis of the image forming condition information table, and laser power which causes deviation in an opposing direction is calculated on the basis of information input in a standby state to update the image forming condition information table.

An image forming apparatus includes a latent image carrier having a surface that moves, an optical writing unit that scans and emits light in a main scanning direction, a developing unit, a first storage unit, a second storage unit, and a control unit. The first storage unit stores first light intensity adjustment data for adjusting the intensity of light emitted from the optical writing unit such that the deviation of the emission intensity of the light in the main scanning direction due to characteristics of the optical writing unit is corrected. The second storage unit stores second light intensity adjustment data which can be set at each irradiation point in the main scanning direction and is for adjusting the intensity of the light emitted from the optical writing unit such that the deviation of image density at an arbitrary irradiation point in the main scanning direction is corrected.

An image forming apparatus includes an image bearer that bears a toner image and a reference toner image, a toner amount detector that detects an amount of toner in the reference toner image, a detected toner amount correction device that corrects the amount of toner detected by the toner amount detector in accordance with a prescribed condition of a previous image formed just before formation of the reference toner image, and a controller that changes a condition of formation of subsequent toner images based on the corrected toner amount.

Image forming apparatus and method capable of changing image formation condition based on detection result of reference image

A device for determining an end of life of an organic photoreceptor includes a potential detecting unit that detects a residual potential of the organic photoreceptor, a temperature detecting unit that detects temperature of the organic photoreceptor in either one of a direct manner and an indirect manner, and a life determining unit that determines the end of life of the organic photoreceptor based on the residual potential detected by the potential detecting unit and the temperature detected by the temperature detecting unit.

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Kanagawa, Japan

Tomohide Takenaka