Konica Minolta Business Technologies, Inc.

Akira Hamada, Legal Representative

Yotaro Sato

Takenobu Kimura

Yoshiko Hamada, Legal Representative

Shuta Hamada

There is described an image forming apparatus equipped with a cleaning unit to clean a belt-type transfer member. The cleaning unit includes: a conductive opposing roller that contacts an inner surface of the intermediate transfer member; a first conductive brush member and a second conductive brush member, both of which are pressed against the conductive opposing roller while putting the intermediate transfer member between them; a cleaning-voltage applying power source to apply a cleaning voltage having a polarity opposite to that of the residual toner onto the first conductive brush member; and an opposing-roller potential controlling unit to control an electric potential state of the conductive opposing roller, so that an electric potential difference, between the first conductive brush member and the conductive opposing roller at a time when the secondary transferring unit is deactivated, is larger than that at a time when the primary transferring unit is activated.

Image forming apparatus with cleaning unit

The invention prevents the phenomenon of occurrence of toner scattering or density fluctuations by changing the appropriate transfer conditions according to the toner charge of the toner images formed on an intermediate image transfer member. The density of toner images formed under prescribed image forming conditions on an intermediate image transfer member is detected, the toner charge is obtained from the detected density, and the pre-transfer charging section is controlled according to the obtained toner charge.

Image forming apparatus and image forming method

There is described an image forming apparatus equipped with a cleaning unit to clean a belt-type transfer member. The cleaning unit includes: a conductive opposing roller that contacts an inner surface of the intermediate transfer member; a first conductive blush member and a second conductive blush member, both of which are pressed against the conductive opposing roller while putting the intermediate transfer member between them; a cleaning-voltage applying power source to apply a cleaning voltage having a polarity opposite to that of the residual toner onto the first conductive blush member; and an opposing-roller potential controlling unit to control an electric potential state of the conductive opposing roller, so that an electric potential difference, between the first conductive blush member and the conductive opposing roller at a time when the secondary transferring unit is deactivated, is larger than that at a time when the primary transferring unit is activated.

A color image forming apparatus may have an image forming unit composed of a plurality of groups which have image carriers and image forming devices.

Color image forming apparatus having pre-transfer discharge electrode

There is disclosed a color image forming apparatus, which makes it possible to prevent a reproduced image from generating image defects, such as a color unevenness, a toner scattering, etc.

Color image forming apparatus

The color image forming apparatus, having: an intermediate transfer member; a plurality of image forming sections provided along the intermediate transfer member; a primary transfer device provided along the intermediate transfer member to transfer toner images formed on each image forming section so that the toner images are superimposed on the intermediate transfer member; a secondary transfer device provided downstream side of the primary transfer device to transfer superimposed toner images through bias voltage; a discharging device having a grid and a discharge electrode provided between the primary transfer device and secondary transfer device; a image density sensor provided along the intermediate transfer member to detect an amount of toner adhesion on the intermediate transfer member; and a control device to control the applied voltage for the discharge electrode in accordance with output of the image density sensor.

A color image forming apparatus includes primary transferring units that transfer toner images of different colors from photoreceptors to an intermediate transfer body, a secondary transferring unit that transfers a color toner image from the intermediate transfer body onto a transfer material, a pre-charging unit placed downstream of the primary transferring units and upstream of the secondary transferring unit and that applies electric charge to the color toner image on the intermediate transfer body before the secondary image transfer with the polarity of the applied electrical charge identical to polarity of the potential of the toner, and a potential adjustment unit placed downstream of the pre-charging unit and upstream of the secondary transferring unit, and that applies an electric charge that has a polarity opposite to that of the potential of the toner to the color toner image on the intermediate transfer body.

Color image forming apparatus with pre-charging unit and potential adjustment unit

There is described an image forming apparatus, which makes it possible to conduct a sufficient discharging operation for a toner image. The apparatus includes an image forming section, an image bearing member, an intermediate transfer belt, a part of which is supported in a state of a flat plane by supporting members, a primary transferring device to transfer a toner image from the image bearing member onto the intermediate transfer member, a secondary transferring device to transfer the toner image onto a transfer material, a scorotron discharging device that is disposed at an upstream side of the secondary transferring device, where the part of the intermediate transfer member is supported in the state of the flat plane, and includes a discharging electrode and a grid to discharge the toner image; and a conductive brush that opposes to the scorotron discharging device and contacts the rear surface of intermediate transfer member.

Image forming apparatus

A color image forming apparatus includes plural developing units that respectively form toner images of different colors on plural photoreceptors, plural primary transferring devices that successively transfer each of the toner images of the plural photoreceptors onto an intermediate transfer belt, which holds a color toner image transferred and superimposed by primary transfer, a secondary transferring device that transfers concurrently the color toner image onto a transfer material, a drive roller that drives the intermediate transfer belt and that is placed between one of the plurality of primary transferring devices which is arranged on the most downstream side in the direction of movement of the intermediate transfer belt and the secondary transferring device, and a controller that controls a discharger discharging the color toner image and the drive of the drive roller.

A color image forming apparatus is described, which makes highly durable image transferring possible. The color image forming apparatus includes: primary transferring devices to transfer unicolor toner images respectively formed on image bearing members onto an intermediate transfer member; a secondary transferring device to transfer the multi-color toner image onto a transfer material; a discharging device before secondary transfer, disposed at a position between a primary transferring device and the secondary transferring device; an electric discharge electrode disposed at a position opposing to the intermediate transfer member; an opposing electrode disposed at a position opposing to the electric discharge electrode while putting the intermediate transfer member between them; and a separating device to make the opposing electrode movable between an operating position at which the opposing electrode contacts the intermediate transfer member and a separating position being apart from the intermediate transfer member.

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Hyogo, Japan

Akira Hamada, Legal Representative