Ricoh Company, Ltd.

Hisao Murayama

Shigeru Watanabe

Shinji Kato

Naoki Iwata

Hideaki Mochimaru

Yasukuni Omata

Hiroshi Yokoyama

Koji Suzuki

Kunihiko Tomita

Norimasa Sohmiya

Chiemi Kaneko

Takatsugu Fujishiro

Takeo Suda

Tomotoshi Nakahara

Hideki Zemba

Hiromitsu Takagaki

Shunji Kato

Mayumi Yoshida

Toshiki Nanya

Kazuo Murai

Ichiro Komuro

Toshiyasu Kawabata

Masami Tomita

Nobuo Iwata

Mitsuru Hashimoto

Hitoshi Ishibashi

Susumu Takahashi

Koji Sakamoto

Tetsuya Morita

Misao Tanzawa

Mitsuhisa Kanaya

Kenya Komada

A latent image carrier includes a thin-walled cylinder with a chargeable photosensitive layer. The latent image carrier is configured to form an electrostatic latent image corresponding to an optically written image. A cylindrical damper including an elastic body disposed inside the latent image carrier. A first end of the cylindrical damper includes a wall extending inward toward an axis of the damper. A second end of the damper, opposite the first end along the axis of the damper, includes an opening, which is open in an axial direction. The wall includes a through-hole connecting an internal cavity and an outside of the damper. An outer diameter of an outermost part of the first end of the damper along the axis of the damper is smaller than an outer diameter of an outermost part of the second end of the damper along the axis of the damper.

Image forming apparatus, drum unit, image forming module, and method of insertion and removal of a damper into and from an image carrier drum

An image forming apparatus includes a photoreceptor belt formed by either a belt or a thin-walled cylinder. A charging unit that sets bias characteristics of the photoreceptor belt has an arrangement to approach towards the photoreceptor belt. A damper is provided on a side of the photoreceptor belt opposite to the side facing the charging unit. The damper absorbs vibrations in the photoreceptor belt through a supporting plate.

An image forming method begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step. An impurity collecting device is associated with a pair of registration rollers which stop the recording medium for a moment to thereby synchronize the recording medium to the toner image.

Image forming apparatus and an impurity collecting device associated with registration rollers

An image transferring device of the present invention includes a first and a second intermediate image transfer body whose surfaces endlessly move while forming a nip in contact with each other. When a sheet nipped by the nip is being conveyed toward a side downstream of the nip in the direction in which the above surfaces move, a first toner image transferred from an image carrier to the second intermediate image transfer body via the first intermediate image transfer body beforehand is transferred to one side of the sheet. At the same time, a second toner image transferred from the image carrier to the first image transfer body beforehand is transferred to the other side of the sheet. One of the two intermediate image transfer bodies is less deformable than the other intermediate image transfer body in the direction of thickness.

Method, system and apparatus for transferring toner images to both sides of a recording medium

An image forming method of the present invention begins with a first image transfer step for thermally transferring a first toner image from a first image carrier to a second image carrier contacting it. Subsequently, in a second image transfer step, the first toner image carried on the second image carrier and a second toner image newly formed on the first image carrier are thermally transferred to opposite sides of a recording medium substantially at the same time. Higher image transfer temperature is assigned to the second image transfer step than to the first image transfer step. Additionally, the second image carrier has a greater roughness than the first image carrier.

Image forming method having transfer temperature difference and apparatus for the same

An image forming apparatus of the present invention includes a first and a second intermediate image transfer belt contacting each other to form a nip for secondary image transfer. While the nip is heated, a sheet is passed through the nip to thereby transfer toner images respectively formed on the first and second belts to opposite surfaces of the sheet at the same time. The nip is sized such that image transfer and fixation can be effected at temperature higher than the melting point or the softening point of toner by 5&#xb0; C. to 50&#xb0; C.

Image forming apparatus configured for double sided printing

A printer includes a transfer belt unit and an intermediate transfer belt. Two papers are fed into the printer one after another at a desired interval. 2nd and 4th images are transferred first onto the transfer belt unit and then onto back surfaces of respective papers. 1st and 3rd images are transferred by the intermediate transfer belt directly onto front surfaces of the respective papers. The 2nd and 4th images are formed on the transfer belt unit in such a manner that a distance between the two images on the transfer belt unit is set longer than the interval between the two papers.

Apparatus for image forming on both sides of a recording medium and image forming method, and image carrier for the same

A multicolor image forming method in which a plurality of latent images are sequentially formed and developed on an image carrier on top of each other on the image carrier. The second and any successive color toners are developed in a non-contact manner. A developed image on a photoconductive element is prevented from being contaminated by subsequent developing stages and toner on the photoconductive element is prevented from contaminating the developer in the subsequent developing stages by reducing the amount of toner which improperly flies between the photoconductive element and the developing stages. Such a prevention of the flight of toner can be accomplished by keeping the potential of the toner on the photoconductive element within a predetermined threshold of the voltage of the toner in the subsequent developing stages. Also, properties of the various toners can reduce the improper flight of the toner such as by controlling the relative amounts of hydrophobic SiO.sub.2 within the toners, controlling the average volume particle size of the toners, controlling the average volume particle size and the average number particle size, and controlling the voltage difference between the toner on the photoconductive element and the toner in the subsequent developing stage(s).

Multicolor image forming method preventing contamination of toner on an

An image forming apparatus capable of collecting a toner remaining on an image carrier after image transfer and conveying the collected toner to a developing unit to reuse it. A toner supplement roller and a toner conveyor are so controlled as to maintain the supplement of a fresh toner from a hopper to the developing unit and the supplement of the collected toner from the toner conveyor to the developing unit in a ratio lying in a predetermined range.

Image forming apparatus with toner recycling device

An image density control method applicable to an electrophotographic copier or similar image recorder for controlling the toner concentration of a two-component developer, i.e., a mixture of toner and carrier to maintain the density of a toner image produced by the developer constant. Predetermined calculations are performed on the basis of the output of a photosensor which is responsive to the toner images representative of reference patterns formed on a photoconductive element.

Image density control method for an image recorder

A multicolor image forming method of the kind sequentially developing a plurality of latent images formed on an image carrier by toners of respective colors and transferring the resulting toner images to a recording medium at the same time. Development in the second color and successive colors is implemented as noncontact type development using a thin layer of nonmagnetic toner. This toner layer satisfies a condition of dt/.epsilon.t&lt;590(.mu.m).sup.2 where dt and .epsilon.t are respectively the thickness and the average volume specific inductive capacity of the layer. The toner for the development in the second color and successive colors is produced by polymerization and has an average volume particle size of 10 .mu.m or less. Development in the first color is implemented by a toner having a relatively sharp particle size distribution, not including relatively large particles, having a sharp charge amount distribution, and not producing particles of low charges. The toner for the development in the first color has a smaller average particle size than the toner for the development in the second and successive colors.

Growing community of inventors

Yokohama, Japan

Hisao Murayama