Ricoh Company, Ltd.

Takuma Higa

Takeshi Takahashi

Kazuaki Kamihara

Masayoshi Nakayama

Masaki Sukesako

Kohei Matsumoto

Hiroyuki Kunii

Tomohide Takenaka

Masahiro Katoh

Toshihiro Sugiyama

Masakazu Terao

Hitoshi Yamamoto

Tadashi Kasai

Takeshi Uchida

Yuichi Aizawa

Wakana Itoh

Masashi Tachi

Emiko Shiraishi

Makoto Yasuda

Kazumi Kobayashi

Kunio Hasegawa

Takamasa Ozeki

Shinichi Akatsu

Keita Sone

Toshiaki Motohashi

Mutsuki Morinaga

Jun Hitosugi

Takatsugu Komori

Shinya Kamijo

Hiroyuki Kunil

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.

Image forming apparatus

An image forming apparatus includes an image forming device to form a toner image onto a recording medium by transferring the toner image directly or indirectly onto the recording medium, the image forming device including a developer to develop a latent image formed on an image carrier into the toner image; and a controller to control the image forming device. The controller determines whether a first estimated time period is greater than a first predetermined time period, the first estimated time period being a time period from a time when image formation of one page of the image completes to an estimated time when image formation of a subsequent page of the image will start; and stops operating the developer based on a determination indicating that the first estimated time period is greater than the first predetermined time period.

Image forming apparatus, image forming system, method of controlling image forming apparatus, and recording medium

An image forming apparatus includes an image bearer, an image forming device, a toner concentration detector, a toner supply device, an image density detector, and a controller including a memory device. At a predetermined timing before image formation is started, the controller adjusts a developing potential to adjust an image density of a detection toner image on the image bearer and drives the toner supply device or the developing device to adjust a toner concentration in the developing device. After the image formation is started, the controller drives the toner supply device to adjust the toner concentration, and, in a predetermined sheet interval, adjusts the target concentration based on the image density of the detection toner image formed in a non-image area of the image bearer. When the toner concentration is higher than the target concentration plus a threshold, the controller suspends image formation and readjusts the developing potential.

Image forming apparatus comprising image density detector and toner concentration detector

An image forming apparatus is provided. The image forming apparatus includes an image forming device to form images of color toners on corresponding image bearers of at least four image bearers; a transferring device to transfer the color toner images on the image bearers to a transfer medium; and a controller to control the image forming apparatus. The controller performs a compulsory toner consumption processing for the color toners to compulsory consume deteriorated toners. When the compulsory toner consumption processing is performed on three or more toners, compulsory consumption toner images of the color toners are formed on the corresponding image bearers and then transferred to the transfer medium to form a compulsory consumption combined toner image including at least two overlaid image portions, wherein the at least two overlaid image portions are arranged side by side with a space therebetween in a width direction of the transfer medium.

Image forming apparatus that performs compulsory toner consumption processing

An image forming apparatus includes a first electric charging unit having an electric discharge wire to uniformly electrify a surface of the electrostatic latent image bearer, a second electric charging unit having a second electric discharge wire to execute a pre-electric charge removal electric charging process by electrifying the surface of the electrostatic latent image bearer subsequent to a transfer process to transfer a toner image, and a first electric charge removing device to diselectrify the surface of the electrostatic latent image bearer by irradiating it with electric charge removing light subsequent to the pre-electric charge removal electric charging process. The first electric charge removing device is disposed within an electric discharge region of the second electric discharge wire on a downstream side of an extreme upstream edge of the electric discharge region of the second electric discharge wire in a rotational direction of the electrostatic latent image bearer.

Image forming apparatus including electric charge removing device and method of forming image

An image forming apparatus includes a latent image bearer; a developing device containing two-component developer and including a developer bearer, a development voltage source, and a toner concentration detector; a toner supply device to supply toner to the developing device; a transfer device; and a controller to keep a toner concentration in the developer in the developing device at a target toner concentration during image formation. The controller executes forced toner consumption in which the developing device supplies the toner to the latent image bearer the toner at a predetermined forced toner consumption timing, while inhibiting the toner supply device from supplying toner. When the toner concentration falls to a prescribed toner density lower than the target toner concentration, the controller completes the forced toner consumption and executes a post-consumption toner supply operation.

An image forming apparatus includes multiple image forming units each including a latent image bearer and a developing device, a transfer device to transfer toner images from the latent image bearers onto a surface of endless rotary member, a cleaner to clean the surface of the endless rotary member, and a control unit to execute a forcible toner consumption process to forcibly consume degraded toner stored in applicable one or more developing devices. The forcible toner consumption process includes a step of forming a toner image formed for forced consumption in a non-image region of the latent image bearer with an amount of toner corresponding to a difference between an image area ratio of a developed image and a prescribed threshold when the image area ratio of the developed image is lower than the prescribed threshold.

Image forming apparatus and method having a forcible toner consumption process

An image-forming apparatus, comprising: a rotatable photoreceptor; a charging device configured to charge a surface of the photoreceptor to be a target charge potential; an exposure device configured to expose a charged portion on the surface of the photoreceptor to form an electrostatic latent image; a developing device configured to develop the electrostatic latent image using toner to form a toner image; a transfer device configured to apply a transfer bias between the photoreceptor and a transfer member by applying an electrical potential of opposite polarity to the target charge potential to the transfer member facing the photoreceptor, and which transfers the toner image on the photoreceptor onto a body to be transferred by the transfer bias; a neutralization device configured to neutralize the surface of the photoreceptor by irradiating the surface with neutralization light after the transferring; and a pre-rotation device configured to perform a pre-rotation process.

Image-forming apparatus

A toner pattern for detecting the degree of toner deterioration is created on a photosensitive element and transferred to an intermediate transfer belt by a primary transfer unit under a transfer condition different from that at the time of image formation. A toner adhesion amount detection unit detects the toner adhesion amount of the toner pattern at multiple places. A degree-of-toner-deterioration calculation unit calculates the degree of toner deterioration on the basis of the variation in data of the toner adhesion amount at multiple places detected by the toner adhesion amount detection unit. A background potential determination coefficient in a process control unit is controlled on the basis of the degree of toner deterioration calculated by the degree-of-toner-deterioration calculation unit.

An image forming apparatus includes an image bearing member, a toner image forming device, an intermediate transfer member, a primary transfer device, a toner adherence detector, a secondary transfer device, and a controller. The toner image forming device forms a toner image and a toner pattern for detection of degradation of toner on the image bearing member. The primary transfer device transfers the toner pattern onto the intermediate transfer member with transfer conditions that deliberately reduce transfer efficiency compared with that for image formation. The toner adherence detector detects an amount of toner adhered to the toner pattern at multiple places. The controller calculates a degree of degradation of toner based on the difference in the amount of toner adhered to the toner pattern detected by the toner adherence detector and adjusts secondary transfer conditions for the secondary transfer device based on the obtained degradation of toner.

Image forming apparatus that adjusts a secondary transfer condition for a secondary transfer device based on a degradation of toner

An image forming apparatus includes a latent image carrier, a developing unit to develop a latent image on the image carrier with developer including toner and carrier, a developer bearing member, a first detector to detect a toner adhesion amount per unit area of a toner image developed by the developing unit, a second detector to detect humidity, and a controller to calculate an index indicating toner chargeability of the carrier based on detection results of the toner adhesion amount obtained by the first detector and perform a given control process based on calculation results thereof and including a data storage unit to store an algorithm to correct the index to a specific value according to a specific humidity, based on detection results of the humidity obtained by the second detector. The controller corrects the index obtained based on the amount of toner adhesion based on the algorithm.

Growing community of inventors

Kanagawa, Japan

Takuma Higa