Ricoh Company, Ltd.

Noriyuki Usui

Ken Amemiya

Kenzo Tatsumi

Masaru Tanaka

Manabu Mochizuki

Hideki Zemba

Haruji Mizuishi

Hiroshi Mizusawa

Toshitaka Yamaguchi

Mayumi Ohori

Kenji Karashima

Kentaro Matsumoto

Asami Mae

Kazuhiko Yuuki

Masakuni Konja

Kohichi Yamazaki

Hajime Oyama

Chikara Imai

Kazuhiko Yuki

Tsumori Satoh

Hidenobu Endo

An image-forming apparatus includes an image-bearing device that holds an electrostatic latent image and a toner image thereon, and a developer container that contains and agitates a developer having at least a toner. The image-forming apparatus also includes a developer-bearing device that carries the developer to develop the electrostatic latent image on the image-bearing device, and a density sensor that detects an optical density of a surface of the image-bearing device and a toner image on the image-bearing device. Further, the image-forming apparatus includes a developer seal that seals the developer in the developer container, wherein the seal is disposed between the developer container and the developer-bearing device, and an actuator configured to actuate the developer container and the developer-bearing device. The image-forming apparatus still further includes a control device that determines whether the developer seal is removed according to information on the optical density of the toner image output by the density sensor.

Image-forming apparatus having a seal for a developer and a method for detecting a removal of the seal

An image forming apparatus includes an image carrier and a developing device to develop a latent image formed on the image carrier by applying two-component developer, including toner, onto the latent image. The developing device includes a developing part containing the two-component developer and a developer stirring device to stir the two-component developer. A toner supplying device supplies toner to the developing part of the developing device, and a toner density detection device detects a toner density of the two-component developer in the developing device. A toner control device calculates a difference between an output value VT of the toner density detection device and a criterion value VTref for controlling the toner density of the two-component developer and controls the toner supplying device based upon the difference. An image density detection device detects an image density of a criterion image formed on the image carrier, and a criterion value correcting device corrects the criterion value VTref based upon an output value of the criterion image density detection device. A decision as to whether to stir the developer in the developing device with the developer stirring device is made based upon a difference between the criterion value VTref and the output value VT from the toner density detection device and an output value of the criterion image density detection device when an image forming operation is started.

Image forming apparatus with improved toner density control

An image forming apparatus is provided, which includes an image bearing member, a transfer roller having a shaft for transferring an image on the image bearing member to a transfer sheet, a bearing mechanism for supporting the shaft, a discharging device for discharging the transfer, and a joint mechanism which mechanically connects the discharging device with the transfer roller at both ends of the shaft. Both of the transfer roller and the discharging device can be integrally detached from and attached to the image forming apparatus without detaching/attaching the bearing mechanism, by use of a handle. Therefore, an operation for replacing the transfer roller and the discharging device can be performed easily.

Image forming apparatus having detachable transfer roller and discharge

An image forming apparatus and method in which a transfer device is provided in a position separated from an image carrier. A transfer sheet is conveyed along and contacting a part of a circumferential surface of the image carrier facing the transfer device when transferring a toner image from the image carrier to the transfer sheet. A conveying guide is included to guide and covey the transfer sheet separated from the image carrier to a fixing unit. The conveying guide includes a guiding member to direct the conveying direction of the transfer sheet upward when the leading edge of the transfer sheet contacts the guiding member and to convey the transfer sheet at a part of the conveying guide or the guiding member in a position higher than the position of the leading edge of the transfer sheet contacting the conveying guide or the guiding member, so that the contact area between the transfer sheet and the image carrier increases, and so that the transfer sheet separates from the image carrier without a discharging of a charge on the transfer sheet.

Image forming apparatus with a device and a method to increase contact

An image forming apparatus in which a transfer device is provided in a position separated from an image carrier. A transfer sheet is conveyed along and contacting a part of a circumferential surface of the image carrier facing the transfer device when transferring a toner image from the image carrier to the transfer sheet. A conveying guide is included to guide and covey the transfer sheet separated from the image carrier to a fixing unit. The conveying guide includes a guiding member to direct the conveying direction of the transfer sheet upward when the leading edge of the transfer sheet contacts the guiding member and to convey the transfer sheet at a part of the conveying guide or the guiding member in a position higher than the position of the leading edge of the transfer sheet contacting the conveying guide or the guiding member, so that the contact area between the transfer sheet and the image carrier increases.

Image forming apparatus with a device to increase contact area between a

An image forming apparatus including a photoconductive drum, a charger which charges the photoconductive drum, an exposing device which irradiates light to the charged photoconductive drum for forming an electrostatic latent image on the photoconductive drum, a developing device which has two component developer which includes magnetic toner and magnetic carriers and a transfer charger to transfer the developed image to a sheet of paper. The bias voltages of the charger, the developing device and the transfer charger are applied from a common high voltage power source. A developing starting voltage of the developing device is higher than a residual voltage of the photoconductive drum.

Developing device for image forming apparatus

A cleaning control device incorporated in electrophotographic image forming equipment for controlling the removal of toner remaining on a photoconductive element or image carrier after image transfer. Before the removal of the remaining toner, the surface potential of the photoconductive element is controlled to a predetermined value on the basis of the amount of remaining toner. Since the reference potential of the photoconductive element is determined in association with the amount of remaining toner, a minimum electric field capable of effecting cleaning is applied at all times. The reference potential is changed in response to aging. The remaining amount of toner is detected by a photoelectric transducer, while the electric field for cleaning is controlled in response to the detected amount of remaining toner. Further, the reference potential is changed in response to the instantaneous humidity around the photoconductive element.

Cleaning control device for image forming equipment

A device for removing deposits from the surface of a photoconductive element which is installed in an electrophotographic copier, facsimile machine, printer or similar image recorder. A rotatable fur-brush is movable into contact with the photoconductive element for removing deposits from the latter. The fur-brush is supported by an arm which is angularly movable between an operative position and an inoperative position assigned to the fur-brush. The arm is in turn driven by a pressing lever. When the image recorder is to start on a copying operation, the deposit removing operation is interrupted immediately. In a further embodiment, the fur-brush may also be movable in a reciprocating motion in the axial direction.

Device for removing deposits from a photoconductive element of an image

A cleaning method applicable to a photoconductive element installed in an electrophotographic copier or similar image recorder of the type performing repetitive steps of charging, exposing, developing, transferring, discharging, cleaning and so forth. The method includes the steps of measuring the surface potential of the photoconductive element remaining after discharging which occurs prior to cleaning, comparing the measured potential with a reference potential, and controlling the output voltage of a discharging device to maintain the surface potential constant.

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Kawasaki, Japan

Noriyuki Usui