Ricoh Company, Ltd.

Semiconductor Energy Laboratory Co., Ltd.

Mitsuru Seto

Yasuo Hirano

Masahide Yamashita

Jun Aoto

Shigeru Fukuda

Narihito Kojima

Hiroshi Nagame

Takashi Bisaiji

Naoki Sugiyama

Takashi Rokutanzono

Shinji Nousho

Naoko Iwata

Shunpei Yamazaki

Takeshi Shintani

Shigenori Hayashi

Hideaki Mochimaru

Naoki Hirose

Yasukuni Omata

Toshiaki Higaya

Norimasa Sohmiya

Noriya Ishida

Junichi Takeyama

Mari Sasaki

Junichiro Hashimoto

Makoto Ohsaki

Masanori Matsuda

Hideo Yuu

An image forming apparatus includes a first image bearing member, a second image bearing member, and a fixing device. A first visual image formed on the first image bearing member is transferred onto the second image bearing member to be transferred from the second image bearing member onto a first side of a recording medium, and a second visual image formed on the first bearing member is transferred from the first image bearing member onto a second side of the recording medium, so that the visual images are obtained on the first and second sides of the recording medium respectively. The visual images on the first and second sides of the recording medium are fixed by the fixing device in a state that the second image bearing member and the recording medium are overlapped with each other.

Image forming apparatus and method for improving image quality of double sided prints

An image forming apparatus of the type sequentially transferring a plurality of toner images formed on an image carrier to an intermediate image transfer body one upon the other (primary transfer) and collectively transferring them from the intermediate image transfer body to a recording medium (secondary transfer) is disclosed. The intermediate image transfer body is implemented by a roller including a metallic core, a base layer formed on the core, and a surface layer formed on the base layer. The base layer and surface layer have a total resistance between 1.57&times;10,&OHgr; and 1.57&times;10,&OHgr; for a unit length (1/cm). The surface layer has a volume resistivity between 1&times;10,&OHgr; cm and 1&times;10,&OHgr; cm. The roller is free from defective image transfer ascribable to the varying environment.

Image forming apparatus including an intermediate image transfer body

An image forming apparatus includes an image carrier, an intermediate transfer element to transfer a developed image, an electrode to apply a bias having preselected polarity to the intermediate transfer element and form an electric field. The intermediate transfer element has an adhering force acting on toner of the developed image that is greater than or equal to an adhering force acting between the toner and the image carrier, and when a frictional charging polarity of the toner which rubs against the intermediate transfer element is the same polarity as the bias applied to the intermediate transfer element from the electrode.

Image forming apparatus with an intermediate transfer element having a

An image forming apparatus of the type transferring a toner image from an image carrier to an intermediate transfer body by primary transfer, and transferring it from the intermediate transfer body to a recording medium by secondary transfer is disclosed. Before the primary transfer, a charge of the same polarity as the charge of the toner image is deposited on the intermediate transfer body. The charge deposited on the transfer body reduces the scattering or blurring of the toner image apt to occur when toners of different colors are superposed, without deteriorating the paper-free feature of the apparatus.

Image forming apparatus

An image forming apparatus in which a toner image formed on an image bearing member is first transferred onto an intermediate transfer element and then onto a transfer member. A potential of the image bearing member is detected and a transfer bias voltage applied to the intermediate transfer element is controlled according to the potential of the image bearing member. Undesired images such as transfer blurring due to discharge at the first transfer area, and a solid image scattering and so-called crow's claw mark due to increase of resistance of the transfer member under low absolute humidities are improved.

Color image forming apparatus having toner and transfer sheet bearing

An image forming apparatus comprises an intermediate transfer unit associated with a photoconductive medium. A first unit transfers a developed image on the photoconductive medium to the intermediate transfer unit such that an intermediate image on the intermediate transfer unit is formed. A second unit transfers the intermediate image from the intermediate transfer unit to a copy sheet such that a reproduced image on the copy sheet is formed. The intermediate transfer device of one aspect of the present invention comprises a surface layer of a mixture containing a friction reducing substance which reduces a coefficient of friction on the surface layer. The intermediate transfer device of another aspect of the present invention comprises a surface layer of a mixture containing a fluorocarbon polymer component and a secondary resin component which are compatible with each other, a visible developed color image being formed on the surface layer.

Image forming apparatus having an intermediate transfer unit with a

An image forming method wherein a toner image on an image carrier is transferred in a first transfer step to an intermediate image transfer element, the transferred toner image on said intermediate image transfer element being subsequently transferred in a second transfer step to a transfer medium. The intermediate image transfer element has a surface whose angle of contact with water is at least 70 degrees and whose position in the triboelectric series is on a positive side with respect to the position of said toner when the toner on the image carrier is negatively charged and on a negative side with respect to the position of the toner when the toner on the image carrier is positively charged.

Electrophotograhic image forming method using an intermediate image

In an image forming apparatus of the type transferring a plurality of toner images of different colors sequentially formed on an image carrier sequentially to an endless intermediate transfer body one above the other by primary transfer, and then transferring the resulting composite color image to a transfer medium by secondary transfer, the intermediate transfer body is provided with surface energy, surface tension or adhering force which is greater than or equal to the corresponding value of the image carrier, but smaller than or equal to the corresponding value of the transfer medium.

An intermediate transfer type image forming apparatus for sequentially performing primary and secondary image transfer with the intermediary of an intermediate transfer medium implemented as, e.g., a belt, and the intermediate transfer member are disclosed. The image transfer medium has a lower surface resistivity on its rear than on its front or image carrying surface.

Intermediate transfer type image forming apparatus and an intermediate

An image forming apparatus capable of reducing the irregularity in the inside resistance of an intermediate image transfer belt thereof to insure uniform images, and reducing the change in the resistance of the belt due to aging to enhance image quality. The belt has a laminate structure including an upper or high resistance layer and a lower or support layer. The specific resistance of the belt is higher in the upper layer than in the lower layer. Optimally, the specific resistance of the upper layer ranges from 1.times.10.sup.10 .OMEGA.cm to 1.times.10.sup.16 .OMEGA.cm.

Intermediate image transfer element and image forming apparatus using

An electrophotographic photoconductor is composed of an electroconductive support, a photoconductive layer formed on the electroconductive support, and a protective layer formed on the photoconductive layer which is composed of a polyol curing-type urethane resin, and satisfies the condition of b/a.ltoreq.0.2, wherein a is the absorbance at 2920 cm.sup.- and b is the absorbance at 2260 cm.sup.-1 in an IR spectrum of the protective layer.

Electrophotographic photoconductor with overlayer of polyol-curing

An electrophotographic photoconductor comprises (a) an electroconductive support, (b) a photoconductive layer formed thereon comprising a selenium alloy, and (c) a protective layer which is formed on the photoconductive layer, contains a binder resin component and an anti-oxidizing agent. In an electrophotographic copying process and an electrophographic copying apparatus using this photoconductor, the protective layer is abraded at a predetermined rate during the copying process in such a fashion that the anti-oxidizing agent contained in the protective layer is always present at the surface of the protective layer, thereby protecting the photoconductor from ozone and ions which are generated during corona charging of the photoconductor.

Electrophotographic photoconductor and electrophotographic copying

An electrophotographic photoconductor comprises an electroconductive substrate, an organic photoconductive layer formed on the electroconductive substrate, and a protective layer formed on the organic photoconductive layer, comprising carbon or a carbon-based material as its main component, in which the difference in the Vickers hardness between the organic photoconductive layer and the protective layer is 2500 Kg/mm.sup.2 or less, and the oxygen concentration at the interface or in the vicinity of the interface between the organic photoconductive layer and the protective layer is 1 atom % or less.

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Yamakita-machi, Japan

Mitsuru Seto