Ricoh Company, Ltd.

Yoshie Tsuchida

Makoto Matsushita

Takeshi Yamashita

Takafumi Miyazaki

Tomoya Adachi

Mitsutoshi Kichise

Takatsugu Iwami

An intermediate transfer tandem type image forming device which has multiple first stage transfer units set parallel and a single power unit which simultaneously applies bias to the multiple first stage transfer units. When executing successive printing or both-sides printing and there is a need to change the bias value of the first stage transfer bias due to a mix of multiple types of recording media, the device is able to hold down electricity consumption, sustain image quality, and form images productively. When executing successive printing or both-sides printing, the application timing of the changed transfer bias due to the detection of a different recording medium to that of the initial medium is placed after the previous first stage transfer of a final color toner image is completed.

First stage transfer bias of an image forming device

An image forming apparatus includes an image carrier; a movable endless belt member forming a nip between the image carrier; and a transfer roller made of metal contacting the belt member at a region corresponding to the nip. At the nip, a toner image on the image carrier is transferred onto the belt member. The transfer roller slidably rotates in bearings supporting its shaft. Members having a higher friction coefficient than that of the transfer roller are provided at end portions of the transfer roller. F&#x3e;Fand F&#x3e;Fare satisfied, where Fis a maximum static friction between the transfer roller and the belt member, Fis a dynamic friction between the transfer roller and the belt member, Fis a maximum static friction between the shaft of the transfer roller and the bearings, and Fis a dynamic friction between the shaft of the transfer roller and the bearings.

Image forming apparatus

An image forming apparatus includes an image carrier, an exposure mechanism, a latent-image forming mechanism, at least one image forming mechanism including a development mechanism to develop the latent image, an intermediate transfer member disposed to contact the image carrier, a primary transfer mechanism to transfer a toner image on the image carrier and superimpose one toner image on another on the intermediate transfer member, a secondary transfer mechanism to transfer the toner image superimposed on the intermediate transfer member onto a transfer material, an asperity detector to detect an asperity profile of a surface of the transfer material to identify a concavity of the transfer material, and a toner adhesion control mechanism to increase an amount of the toner transferred to intermediate transfer member according to the concavities in the surface of the transfer material identified by an asperity detector, after a predetermined time elapses.

Image forming apparatus and control method therefor

A first degradation degree detector detects a first degradation degree of one of a plurality of image forming devices for forming toner images, respectively, which is provided at an extreme downstream position in a direction of rotation of an intermediate transfer member. A first degradation degree judgment device judges whether or not the first degradation degree of the extreme downstream image forming device detected by the first degradation degree detector reaches a first level of deterioration. A bias controller decreases a bias to be applied by a transfer device to transfer the toner images, which are formed by the plurality of image forming devices and transferred on the intermediate transfer member, onto a transfer sheet, when the first degradation degree judgment device judges that the first degradation degree of the extreme downstream image forming device detected by the first degradation degree detector reaches the first level.

Image forming apparatus and image forming method capable of effectively transferring toner images

An image forming apparatus includes an exposure mechanism to form a latent image by exposure, a latent-image carrier to hold the latent image, a charging mechanism to charge the latent-image carrier evenly, a development device to develop a latent image on the latent-image carrier into a toner image, a transfer mechanism to transfer the toner image formed on the latent-image carrier onto a transfer material, at least one asperity profile reading mechanism to read an asperity of an entire image area of the transfer material at least in a width direction thereof onto which a toner image is to be transferred, and a control mechanism to adjust a toner adhesion amount of the toner image transferred to the transfer material in accordance with a localized asperity of a surface of the transfer material read by the asperity profile reading mechanism.

An image forming apparatus includes an image carrier, an intermediate transferring body and a contact type secondary transferring member transferring an image from the intermediate transferring body to a recording medium. The apparatus forms an image with respective developers for multiple colors and uses a predefined adjustment pattern to make density adjustment and position adjustment of respective color images. After execution of the density adjustment and/or the position adjustment, a stain prevention pattern is formed with a yellow developer to cover an area where the adjustment pattern is attached to the secondary transferring member.

Image forming apparatus and image forming method

An image forming apparatus includes an image carrier, a toner image forming unit configured to form a toner image having a predetermined polarity on the image carrier, an intermediate transfer body facing the image carrier, a primary transfer member configured to transfer the toner image on the image carrier onto the intermediate transfer body, a secondary transfer member configured to transfer the toner image on the intermediate transfer body onto a recording medium, and a contacting member in contact with the image carrier and configured to remove residual toner remaining on the image carrier after the toner image is transferred by the primary transfer member onto the intermediate transfer body and to pass the removed residual toner to the intermediate transfer body. A bias voltage with the same polarity as the predetermined polarity of the toner image is applied to the contacting member.

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Osaka, Japan

Yoshie Tsuchida