Ricoh Company, Ltd.

Yasuhide Matsuno

Naoki Nakatake

Yuji Nagatomo

Takeshi Yamashita

Takahiro Sanada

Tomoya Adachi

Yasuhiro Fujiwara

Kyoko Abe

Minoru Toyoda

Takafumi Miyazaki

Rumi Miyazaki

Kenji Nakamura

Tamotsu Ikeda

Masanari Fujita

Tomohiro Kubota

Yoshihiro Mikuriya

Yoshie Iwakura

Tsuyoshi Nozaki

Takuya Kadota

Hitoshi Fujiwara

Takayuki Nakamura

Keiji Kunimi

Shin Murayama

Takahiro Yoshimi

Yoshimichi Ishikawa

Ryuji Inoue

Kazuoki Fuwa

Shoh Tsuritani

Tomohiro Fukao

Atsushi Takehara

Shin Yamamoto

Yutaka Naitoh

Mitsutoshi Kichise

Shinichi Arasawa

Tomohiko Fujii

Tomoharu Miki

Hiroaki Katoh

Akihiro Kawasaki

Yoshio Sakagawa

Yasuharu Kawarasaki

Shinji Minami

Yuta Takeuchi

Shogo Kezuka

Yutaro Kaku

An image forming apparatus includes an image bearer, a charger, a developing device, and a transferor. The charger is disposed in contact with the image bearer to charge the image bearer. The developing device supplies toner to the image bearer to form a toner image on the image bearer. The transferor transfers the toner image on the image bearer to a recording medium or an intermediate transferor. The developing device collects transfer residual toner remaining on the image bearer after transfer of the toner image. The toner contains base particles and an external additive. The external additive has a volume average particle diameter of 5 nm or more and 50 nm or less. A content of the external additive is 1.8% by mass or less in the toner.

Cleanerless image forming apparatus with toner containing 1.8% by mass or less an external additive having a diameter of 5-50 nanometers

An image forming apparatus includes an image forming device and circuitry. The image forming device forms an image with colorants of different colors. The circuitry determines whether there is a possibility that a shortage of a colorant adhesion amount occurs in primary-color image formation using a colorant of a primary color and cause the image forming device to perform two-color image formation in which only secondary-color image formation using a colorant of a secondary color different from the colorant of the primary color is added to the primary-color image formation using the colorant of the primary color to form an image to be formed with the colorant of the primary color, when the circuitry determines that there is a possibility that the shortage of the colorant adhesion amount occurs in the primary-color image formation using the colorant of the primary color.

Image forming apparatus

An image forming apparatus includes a photoconductor, a charging roller to charge the photoconductor, a power source to apply a charging bias to the charging roller, a current sensor to generate a feedback signal representing an output current flowing from the charging roller to the photoconductor, a memory, and circuitry. The circuitry calculates film thicknesses of a photoconductor film of the photoconductor at a plurality of points of time based on a voltage of the charging bias and the output current, calculates travel distances of the photoconductor charged at the plurality of points of time, associates the film thicknesses with the travel distances, stores the film thicknesses and the travel distances in the memory, calculates a present estimated film thickness based on the film thicknesses and the travel distances, and calculates an estimated film thickness range corresponding to a present travel distance based on the present estimated film thickness.

Image forming apparatus to calculate film thicknesses of a photoconductor film of a photoconductor, image forming method, and non-transitory recording medium storing image forming program

An image forming apparatus includes a latent image bearer, a charging roller, a first cleaner, a second cleaner, and a rotation controller. The latent image bearer bears a latent image on a surface thereof. The charging roller charges the latent image bearer. The first cleaner cleans the surface of the latent image bearer. The second cleaner cleans a surface of the charging roller. The rotation controller controls the latent image bearer to execute a set of backward rotation and first forward rotation at least once during a non-image formation time period, and either temporarily stop and start second forward rotation or continuously execute the second forward rotation by a rotation distance corresponding to at least one rotation of the charging roller.

Image forming apparatus and driving method for driving image forming apparatus

A developing device includes a developer bearer and a regulation member. The developer bearer bears developer on a surface thereof. The developer bearer is rotatable forward and in reverse. The regulation member is disposed in contact or non-contact with the surface of the developer bearer to regulate amount of the developer on the developer bearer. In a non-development period, when the developer bearer rotates in a direction of reverse rotation opposite to a direction of forward rotation in which the developer bearer rotates in a development period, the developer bearer stops a series of rotating operations after the developer bearer rotates in the direction of forward rotation as a last rotating operation. A total rotation amount of forward rotation is set to be greater than a total rotation amount of reverse rotation in the series of rotating operations.

Developing device and image forming apparatus including same

A process unit includes a rotatable image bearer to bear a toner image on a surface thereof; a developer bearer to supply developer to the image bearer and including a first range, a second range different in property from the first range and adjacent to the first range on an outer side in an axial direction via a first boundary, and a second boundary on an outer side of the first boundary in the axial direction; a cleaning member to remove residual developer from the image bearer; and an abutment part disposed to contact the surface of the image bearer to remove a foreign substance from the image bearer. The abutment part is disposed astride at least one of a first position on the image bearer corresponding to the first boundary, and a second position on the image bearer corresponding to the second boundary.

Process unit and image forming apparatus incorporating same

Image forming apparatus, image forming method and process cartridge

A fixing device includes a nip formation pad disposed opposite an inner circumferential surface of an endless belt and a pressing rotary body pressed against the nip formation pad via the endless belt to form a fixing nip between the endless belt and the pressing rotary body, through which a recording medium is conveyed. The pressing rotary body has a diameter increasing from a center to each lateral end in an axial direction thereof. The nip formation pad includes a projection disposed downstream from a rotation axis of the pressing rotary body in a recording medium conveyance direction. The projection projects toward the pressing rotary body in an amount increasing from each lateral end to a center in a longitudinal direction of the nip formation pad parallel to the axial direction of the pressing rotary body.

Fixing device and image forming apparatus

An image forming apparatus includes a latent image forming device that forms a latent image, a latent image carrier that carries the latent image, a development device that develops the latent image, and a controller. The development device includes a developer carrier that faces the latent image carrier and carries toner on a rotary surface thereof that rotates in a rotation direction perpendicular to a width direction of the developer carrier, and a regulation member that regulates the thickness of a layer of the toner on the surface of the developer carrier. The controller moves the toner on lateral end regions in the width direction of the surface of the developer carrier toward the latent image carrier. The end regions are located outside a maximum image forming region within a regulation member facing region of the surface of the developer carrier facing the regulation member.

Reducing toner adhesion to a development device of an image forming apparatus

An optical writing head positioning mechanism includes spacers provided between a latent image carrier for carrying an electrostatic latent image and an optical writing head for exposing the latent image carrier. The spacers each include at least one carrier contact surface that contacts the latent image carrier and at least one head contact surface that contacts the optical writing head to determine an interval between the latent image carrier and the optical writing head. The latent image carrier is in contact with a cleaning member that cleans a cleaning area on a surface of the latent image carrier. In at least one of the spacers, the at least one carrier contact surface includes plural carrier contact surfaces not disposed on edges of the cleaning area, and one of the edges of the cleaning area is located between two adjacent ones of the plural carrier contact surfaces.

Optical writing head positioning mechanism, process cartridge, and image forming apparatus

Provided is a color image forming apparatus that includes: image carriers that form toner image of black and other colors; an intermediate transfer body that makes contact with the image carriers; and transfer units that transfer the toner images on the image carriers to the intermediate transfer body. A line velocity difference is set between the image carriers and the intermediate transfer body. An accelerated cohesion degree of toner is equal to or larger than 54%. A linear velocity difference Xbetween the image carrier for black and the intermediate transfer body satisfies a relation of 0&#x3c;X&#x2266;1.2 mm/sec. A linear velocity difference Xbetween the image carriers for the colors and the intermediate transfer body satisfies a relation of 2.1&#x2266;X&#x2266;4.0 mm/sec.

Color image forming apparatus with a line velocity difference set between image carriers

An image forming apparatus including a latent image bearing member, a charger, a latent image forming device, a developing device, and a transfer device is provided. The transfer device is adapted to transfer a toner image formed on the latent image bearing member onto an intermediate transfer member or a recording medium by action of a transfer elected field in a transfer position where the latent image bearing member faces the transfer device. When a non-charged portion of the latent image bearing member that has not been charged to a predetermined potential by the charger passes through the transfer position, a strength of the transfer electric field is lowered than that in transferring the toner image.

Image forming apparatus and image forming method

A developer regulator to restrict an amount of a developer, including a base portion; an intermediate portion continuous with the base portion, the intermediate portion having a flat area on one face, the flat area having a roughened surface; and a distal end continuous with the intermediate portion, the distal end being bent relative to the base portion in a direction opposite the one face in which the flat area is formed.

Developer regulator, development device, and image forming apparatus incorporating same

An image developing device includes a developer supporting body; a first conveyance path in which a first conveyance member is arranged; a second conveyance path in which a second conveyance member is arranged; and a partition member that partitions the first conveyance path and the second conveyance path and that has a first communication port and a second communication port. The first communication path and the second communication path communicates with each other through the first communication port and the second communication port. The image developing device includes a developer amount detection unit that includes an optical detection unit arranged in the second conveyance path and that optically detects an amount of the developer in the image forming device. The developer is caused to accumulate in the vicinity of the developer amount detection unit.

Image developing device, process cartridge including image developing device, and image forming device including image developing device

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Osaka, Japan

Yasuhide Matsuno