Ricoh Company, Ltd.

Rumi Miyazaki

Kyoko Abe

Tomoya Adachi

Naoki Nakatake

Takeshi Yamashita

Yuji Nagatomo

Atsushi Takehara

Takafumi Miyazaki

Tomohiro Kubota

Yasuhiro Fujiwara

Yasuhide Matsuno

Takahiro Sanada

Keiji Kunimi

Yoshie Iwakura

Hitoshi Fujiwara

Shoh Tsuritani

Yutaka Naitoh

Minoru Toyoda

Tomohiko Fujii

Hiroaki Katoh

Yasuharu Kawarasaki

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 an image forming device to form a toner image according to image data, a density adjustment toner pattern, and a timing adjustment toner pattern on an image bearer, a detector to detect the density adjustment toner pattern and the timing adjustment toner pattern, and an image density adjustment unit to execute image density adjustment based on an amount of toner adhering to the density adjustment toner pattern detected by the toner amount detector. The image density adjustment unit causes the image forming device to form the timing adjustment toner pattern before the density adjustment toner pattern is formed, and the image density adjustment unit adjusts a detection timing of the density adjustment toner pattern based on a detection timing of the timing adjustment toner pattern detected by the toner amount detector.

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 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

An image forming apparatus includes an image carrier, a toner-image forming unit, a photosensor, an information obtaining unit, and a toner-amount calculating unit. The toner-image forming unit forms a toner image on the image carrier with toner. The photosensor detects a toner area where the toner is sticking to the image carrier. The information obtaining unit obtains particle-size-change information about how particle size distribution of the toner changes over time. The toner-amount calculating unit calculates a toner amount of the toner image based on the toner area and the particle-size-change information.

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Osaka, Japan

Rumi Miyazaki