Ricoh Company, Ltd.

Kabushiki Kaisha Ricoh

Koji Hirakura

Yoshinori Hayashi

Takao Yamaguchi

Seizo Suzuki

Hiroyuki Suhara

Wasaburo Ohta

Magane Aoki

Kenichi Takanashi

Takeshi Ueda

Tatsuya Ito

Satoru Itoh

Taira Kouchiwa

Yasuo Sawada

Kenta Watase

Koji Sakamoto

Yoshihiro Ogata

Harumi Takahashi

Yutaka Koizumi

Takuro Sekiya

Nobuyuki Yanagawa

Shigeru Suzuki

Satoru Tomita

Yutaka Ebi

Chikara Imai

Masumi Ikesue

Fuyuhiko Matsumoto

Itsuo Ikeda

Takeshi Iijima

Masaaki Nomura

Zenjiro Okuno

Tamio Ohhori

Takahiko Kitamura

An image forming apparatus includes an input part for inputting information, a processing part for processing the information; a storing part for storing the information, an output part for outputting the information, a writing part for writing desired information to a portable recording medium, and a scanner for scanning an original as image information. In image forming apparatus, the image information scanned by the scanner is stored in the storing part, and wherein the input part, the processing part, the storing part, and the output part are centralized at one place, and send and receive the information to and from each other.

Image forming apparatus

An optical scanning lens is used in a scanning and image forming optical system which gathers a light flux deflected by a light deflector in the vicinity of a surface to be scanned. The lens is formed by plastic molding of polyolefin resin, and the following condition is satisfied: 0&#x3c;|&#x394;n(x)&#x2212;min[&#x394;n(x)]|&#x3c;34&#xd7;10, where &#x394;n(x) denotes a refractive-index distribution existing inside the lens, in a range which the light flux passes through, in the lens, and min[&#x394;n(x)] denotes the minimum value of the &#x394;n(x).

Optical scanning lens, optical scanning device and image forming apparatus

An optical scanning lens which is used in a scanning and age forming optical system which gathers a light flux deflected by a light deflector in the vicinity of a surface to be scanned. The lens is formed by plastic molding of polyolefin resin, and the following condition is satisfied: 0&#x3c;|&#x394;n(x)&#x2212;min[&#x394;n(x)]|&#x3c;34&#xd7;10, where &#x394;n(x) denotes a refractive-index distribution existing inside the lens, in a range which the light flux passes through, in the lens, and min[&#x394;n(x)] denotes the minimum value of the &#x394;n(x).

An optical scanning lens is used in a scanning and image forming optical system which gathers a light flux deflected by a light deflector in the vicinity of a surface to be scanned. The lens is formed by plastic molding of polyolefin resin, and the following condition is satisfied: 0<&verbar;&Dgr;n(x)&minus;min&lsqb;&Dgr;n(x)&rsqb;&verbar;<34&times;10 , where &Dgr;n(x) denotes a refractive-index distribution existing inside the lens, in a range which the light flux passes through, in the lens, and min&lsqb;&Dgr;n(x)&rsqb; denotes the minimum value of the &Dgr;n(x).

A developing unit is disclosed which utilizes a two-component developer comprising a toner and a carrier to develop an electrostatic latent image formed on a photosensitive member. The unit comprises a doctor for controlling the amount of developer supplied onto a developing sleeve, a flow plate for receiving a quantity of developer scraped off by the doctor and allowing it to flow therealong, at least one deflector plate disposed at an angle on the flow plate for causing the developer to be directed toward one side, and a screw assembly for conveying the developer which has been directed toward one side to the other side and returning it to the interior of a developer vessel.

Developing unit of dry type

An original to be copied is placed in a given position. An exposure optics including a movable part is employed to focus an optical image of slitwise segment of the original on a photosensitive member. The photosensitive member moves in a given direction and at a given speed throughout the exposure. The location where the image of slitwise segment of the original is focused moves through the space of the arrangement at a given speed and in a direction opposite from the direction of movement of the photosensitive member throughout the exposure. Consequently, the location corresponding to the initiation of the exposure is situated downstream as viewed in the direction of movement of the surface of the photosensitive member while the location corresponding to the end of the exposure is situated upstream as viewed in the same direction. Upon termination of the exposure, the photosensitive member continues its movement which is the same as during the exposure while the movable part of the exposure optics returns to its start position.

Process of exposing photosensitive member

In a copy paper separating device for use in a transfer type electrophotographic copying machine which includes a conductive carrier member, preferably in the form a conductive endless belt extended between a pair of pulleys. The conductive carrier member is disposed in the periphery of the photosensitive member to which a copy paper is brought into contact for the transfer of a toner image formed on the photosensitive member. The potential of the conductive carrier member is maintained nearly at zero level during the first step of the separating operation; whereas, the potential of the carrier member is increased to a predetermined value of the polarity opposite to that of the toner image during the second step.

Transfer medium separating device

A toner concentration control system for use in electrophotographic copying machines or the like, wherein light from a single light source is simultaneously detected by two photosensors, or by two sensing portions of a single photosensor, the light striking one of the photosensors (or portions) directly and the other after being reflected from developer comprising toner and carrier particles as the developer passes a viewing window in a chute provided for the transport thereof within the copying machine, the intensity of the reflected light being inversely proportional to the concentration of toner in the developer, whereby, by comparison of the output of the photosensors (or portions) by conventional means, the concentration of toner in the developer can be determined and adjusted, the photosensors (or portions) having been carefully selected as a pair of their essentially identical characteristics and response to ambient conditions so that, for example, their parallel deterioration with time or their identical response to changes in temperature will not adversely affect the accuracy of the toner-concentration determination, the portion of the embodiment comprising the light paths, the photosensors, the light source and the external surface of the viewing window being completely sealed from the remainder of the interior of the copying machine, thereby eliminating the adverse affects on measurement and long-term reliability of inevitable airborne particles of developer.

Toner concentration control apparatus

A toner concentration control apparatus of the type for allowing developer to pass through a chute, which is capable of detecting stopping of the flow of the developer in the chute, clogging of the chute with the developer, or coating of a viewing window formed in the chute with the developer, and upon occurrence of such abnormalities, minimizing the trouble therefrom in the operation of the copying machine, in which light from a single light source is simultaneously detected by two photosensors, the light striking one of the photosensors directly and the other after being reflected from the developer comprising toner and carrier particles as the developer passes a viewing window in the chute provided for the detection of the toner concentration within the copying machine, and the output of the photosensors is compared with each other and the concentration of toner in the developer can be determined and adjusted by the comparison value. In addition, the output of the photosensor which receives the light reflected from the developer contains an A.C. component signal which indicates the flow of the developer along the inside of the viewing window, and a D.C. component signal which corresponds to the concentration of toner in the developer, and, by detecting the presence or absence of the A.C. component signal, abnormalities in the flow of developer are detected.

A toner image of an original document is formed on a photoconductive drum (1) and transferred onto a copy sheet (4) which is moved into contact with the drum (1) by a corona charging unit (5) which applies an electrostatic charge to the copy sheet (4) causing the toner image to be transferred thereto. The copy sheet (4) is separated from the drum (1) by a conductive belt (6). The belt (6) is initially grounded so that the leading edge of the copy sheet (4) is attracted thereto by induced electrostatic charge. A voltage of the same polarity as the transfer charge is then applied to the belt (6) to prevent transfer of the toner image back to the drum (1).

Electrostatic copying apparatus

A photoconductive drum is formed with a photoconductive dielectric layer for producing an electrostatic image and an endless transfer belt is formed with a dielectric layer thereon. A toner substance is applied to the drum to produce a toner image, and a copy sheet is pressed between the belt and drum to transfer the toner image to the copy sheet. An electric potential of the same polarity as the electrostatic image is applied to the copy sheet to attract the toner from the drum onto the copy sheet. The potential has a magnitude which is slightly less than a magnitude at which charge transfer from the belt to the drum occurs due to dielectric breakdown through the copy sheet or field emission from the copy sheet to the drum which would degrade the electrostatic image. The method enables a large number of copies to be produced from a single electrostatic image through repeated development and transfer.

Toner image transfer method and apparatus for electrostatic photography

A powdered developer (26) comprising carrier and toner particles is caused to flow by gravity downwardly through a passageway (71). A transparent electrode (62) is disposed in the passageway (71). A light source (64) and photosensor (66) are arranged on opposite sides of the electrode (62) for sensing an amount of attracted toner. The electrode (62) is first de-energized and cleaned by aprtially restricting the passageway (71) below the electrode (62) and allowing developer (26) to accumulate in the passageway (71) from the restriction upwardly past the electrode (62) while a restricted amount of developer (26) flows downwardly through the restriction. Then, the restriction is removed and the passageway (71) blocked above the electrode (62), allowing the accumulated developer (26) to flow downwardly past the electrode (62). Then, the passageway (71) is completely unblocked and the electrode (62) energized with an electric potential causing toner to be attracted thereto. After a predetermined length of time the passageway (71 ) above the electrode (62) is blocked and the output of the photosensor (66) indicates the amount of toner attracted to the electrode (62) and thereby the developing ability of the developer (26). The output of the photosensor (66) after cleaning the electrode (62) may be compared with the final output to provide a reference valve which is compensated for variables such as electrode contamination, electric potential variation and the like.

Toner developing ability measuring system for electrostatography

In controlling the operation of an electrostatic apparatus to produce a large number of copies from an electrostatic image in a multiple copy process there is utilized a toner substance comprising a magnetic carrier composition in which each particle of the composition comprises a ferromagnetic material and a resin, the effective conductivity of the composition being determined by testing means separate from the electrostatic apparatus such that the effective conductivity is measured while the composition is free of absorbed water vapor and other gases encountered under operating conditions with the electrostatic apparatus.

Toner composition for multiple copy electrostatic photography

This invention provides an electrostatic copying method for forming multiple copies by repeating the process of developing an electrostatic latent image formed on an electrophotographic insulating material with a dry developer comprising electroscopic powder and carrier particles and the process of transferring the thus developed image onto a transfer sheet continuously without erasing said latent image, said carrier particles consisting of an essentially homogeneous ferromagnetic oxide having an apparent electric conductivity in the range of 10.sup.-11 -10.sup.-5 .OMEGA..sup.-1 cm.sup.-1, thereby rendering it possible to form multiple copies compared with the conventional copying methods.

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Tokyo, Japan

Koji Hirakura