Ricoh Company, Ltd.

Kentaroh Tomita

Hitoshi Ishibashi

Shin Hasegawa

Kayoko Tanaka

Nobutaka Takeuchi

Kohta Fujimori

Yushi Hirayama

Shinji Kato

Kiyonori Tsuda

Naoto Watanabe

Shuji Hirai

Koichi Sakata

Akio Kosuge

Koichi Kato

Kohichi Utsunomiya

Junichi Terai

Satoru Komatsubara

Keiko Matsumoto

Akira Yoshida

Masumi Sato

Yasufumi Takahashi

Emiko Shiraishi

Yuki Oshikawa

Takehide Mizutani

Mugijirou Uno

Maiko Koeda

Eriko Maruyama

Takayuki Tamaki

Chiemi Hirano

An image forming apparatus includes a control unit configured to perform, if a suitable color measurement area suitable for color measurement of a combined color is found in an image, a color-reproduction-accuracy increasing process while, if not, to perform a deposition-amount stabilizing process. In the color-reproduction-accuracy increasing process, a control parameter is adjusted so as to reduce a difference between a result of the color measurement on the suitable color measurement area and a desired color. In the deposition-amount stabilizing process, a plurality of test primary-color toner images are formed by an image forming unit, and a control parameter for the image forming unit are adjusted so as to reduce a difference between each of results of toner deposition amount measurement on the test primary-color toner images and a corresponding target deposition amount.

Image forming apparatus increasing combined-color reproduction accuracy and stabilizing toner disposition amount

A developing device capable of preventing scattered developer from being discharged and of stably supplying a developer to a latent image carrier by preventing the developer from being discharged despite that the amount of developer within the developing device is not increased, and an image forming apparatus including the developing device. When the bulk of the developer existing in the vicinity of the downstream end in the conveyance direction of the supply conveyance path exceeds the height level of the developer discharge port, the developer that has reached the height level of the developer discharge port is discharged to the outside of the developing device by the developer discharge port and developer conveyance path serving as the developer discharge device.

Developing device and image forming apparatus using same

A developing unit, which is incorporated in an image forming apparatus, includes a developer case to accommodate a two-component developer including toner and carrier, a developer bearing member bearing the two-component developer to supply the developer to an image, a developer supply path formed inside the developer case to supply the developer along the developer bearing member, an agitation and conveyance member disposed in the developer supply path, a toner collecting mechanism to collect toner after development, and a collected toner conveyance path formed inside the developer case and including a collected toner conveying member. The collected toner conveyance path and the developer supply path are arranged in communication with each other in the vicinity of one end portion of the collected toner conveyance path in a direction of conveyance of collected toner so as to circulate toner unused for development.

Developing unit, image forming apparatus incorporating same, and method of controlling amounts of toner

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

A developing device capable of conveying discharged developer to the outside of the device well by preventing developer from firmly adhering within a discharge conveyance path, as well as an image forming apparatus and a process cartridge having this developing device. A developing device, having: a developing roller; a developer conveyance path having a supply screw and a supply conveyance path; a toner replenishment controller for replenishing the developer to the developer conveyance path; a discharge conveyance path for conveying the developer to the outside of the developing device; a discharge screw serving as a discharge conveying member for applying a conveying force to the developer within the discharge conveyance path; and a developer discharge port serving as developer discharge means for discharging the developer to the discharge conveyance path, wherein the conveying force is applied to the discharged developer intermittently by the discharge screw serving as a discharge conveying member, whereby a shock is applied intermittently to the discharged developer within the discharge conveyance path.

Developing device, image forming apparatus and process cartridge in which a shock is applied intermittently to the discharged developer

An image forming apparatus includes an image carrier configured to carry an image and a charger to which a direct current voltage overlapped with an AC voltage is applied as a charging bias to charge the image carrier. The charger is positioned in contact or contactlessly with the image carrier. The AC voltage applied to the charger in an adjustment of the AC voltage is not less than twice a charging start voltage Vth at which the image carrier starts to be charged.

Image forming apparatus and method of adjusting charge bias

An image forming apparatus includes an image forming unit configured to form a plurality of toner images on an image carrier, an optical detector configured to detect reflection light from the toner image, and dedicated to detect infrared rays and near-infrared rays, and a controller configured to perform a predetermined control using a detection results of the optical detector. Gradation pattern that is comprised of a plurality of toner patches formed in the image forming unit with an image forming condition to have different adhesive amounts, and is formed of at least two colors, and detection values detected by the optical detector are used for the predetermined control.

Image forming apparatus capable of efficient toner concentration control

A developing device which can stably supply a developer to a latent image carrier by preventing the scattered developer from being discharged and thereby preventing the developer from being discharged despite that the amount of developer within the developing device does not increase, and an image forming apparatus using the developing device. A block member serving as a scattered developer discharge prevention member is provided so as to block a path through which the developer scattered as a result of a conveyance operation of a supply screw serving as a developer conveying member moves toward a developer discharge port. Accordingly, the scattered developer is prevented from reaching the developer discharge port and being discharged therefrom.

An image forming apparatus includes an image carrier configured to carry an electrostatic latent image, a developing device configured to develop the electrostatic latent image with a two-component developer including toner and magnetic carrier, a toner supplier configured to supply the toner to the developing device, a toner concentration detector configured to detect toner concentration in the two-component developer inside the developing device, and a controller. The controller is configured to detect first information to determine toner replacement amount in the developing device during a predetermined time period and second information to determine a charge characteristic of the toner in the developing device, change a toner concentration control reference value based on the first information and the second information, and control the toner concentration based on an output from the toner concentration detector and the toner concentration control reference value.

An image forming apparatus includes an image carrier configured to carry an image and a charger to which a direct current voltage overlapped with an AC voltage is applied as a charging bias to charge the image carrier. The charger is positioned in contact or contactlessly with the image carrier. A controller performs an adjustment to the AC voltage multiple times to gradually bring the AC voltage to a target value.

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Kanagawa, Japan

Kentaroh Tomita