Abstract: A developing device for developing an electrostatic latent image formed on an imaging surface includes a developing electrode disposed opposite to the imaging surface and a control circuit for controlling the potential of the developing electrode. In one form, when the control circuit causes the developing electrode to be electrically floating, the upper limit of the voltage excursion is set at different levels as desired. In another form, the control circuit includes a sensor for sensing the potential of the imaging surface thereby allowing to carry out so-called fixed bias or auto-bias developing modes. In a further form, the mode of developing operation is automatically set depending upon the position of a pressure plate which is to be placed on an original for keeping the original in position during copying process.

Abstract: An apparatus for forming multicolor electrophotographic images through a wet-type developing process has charging, exposure, development, transfer, and cleaning devices disposed around a rotatable latent image carrier. The development device has at least one roller disposed in confronting relation to the latent image carrier, and a development housing in which the roller is rotatably disposed. During the developing process, the development device is supplied with a desired one of liquid developers of different colors stored in respective liquid developer tanks.

Abstract: A process for treating exhaust gas from an electrophotographic machine which comprises oxidizing, in the presence of a heated oxidation catalyst, an odorous exhaust gas generated in course of the steps of developing an element being developed by means of a developer, transferring the thus developed image onto a transfer sheet and/or heating a copy material consisting of said element being developed or said transfer sheet thereby to make said exhaust gas odorless, and an apparatus therefor.

Abstract: A wet type electrophotographic copying machine of the type capable of performing one copy making process during substantially two revolutions of a photoconductor, which is provided with means for forming a liquid developer deposition portion by charging, exposure and development, on the downstream side of an image formation area on the photoconductor, the liquid developer deposition portion capable of substantially narrowing the gap between the photoconductor and a squeegee roller, whereby the squeezing of excess developer from the surface of the photoconductor can be performed at the squeezing initiation point on the photoconductor, thus attaining a sharp squeezing effect, and the adhesion of the excess liquid developer to an image transfer material can be prevented.

Abstract: A magnetic brush development apparatus includes a developer containing magnetic powder therein which is attracted to a non-magnetic support member by a magnet arranged therein. The developer is brought into contact with a latent electrostatic image bearing member which is located in a development section for developing the latent electrostatic image. The magnet has substantially one magnetic pole portion capable of producing a magnetic field having a plurality of peaks in the intensity of the magnetic field located in the development section.

Abstract: An electrophotographic process and apparatus of two revolutions/copy, wet developing type is provided in which a corona discharger provides the combined functions of a charging and an image transfer, and in which a combined developing and cleaning unit is used. The unit includes a combined developing and cleaning roller which is driven for rotation in different directions and at different speeds during the developing and the cleaning step.

Abstract: First and second sensors (37), (39) are provided in a developing tank (36) containing a liquid developer consisting of a liquid carrier or dispersant and toner particles dispersed in the carrier. The first sensor (37) measures the electrical resistivity of the developer whereas the second sensor (39) measures the optical transmissibility thereof. Additional toner is supplied into the developer to maintain the transmissivity at a value which is a predetermined function of the resistivity. The transmissibility value is reduced as the resistivity increases, thereby maintaining the copy image density constant. The first sensor (37) includes two electrodes immersed in the developer and an A.C. or D.C. voltage is applied thereacross. The current flow through the electrodes (37) and thereby the developer is measured to determine the resistivity of the developer. Where the applied voltage is D.C.

Abstract: A plurality of parallel wires (27) are disposed between a corona discharge electrode (24) and a surface (13) to be electrostatically charged. The surface (13) is moved relative to the electrode (24) and wires (27). The wires (27) are equally spaced from each other in a plane (28) which is inclined relative to the surface (13) in such a manner that the spacing between the wires (27) and the surface (13) increases in the direction of movement of the surface (13) relative to the wires (27). A high voltage for corona discharge is applied to the electrode (24). A low voltage is applied to the wires (27) to prevent the surface (13) from being charged above a predetermined potential. The low voltage may be applied to the wires (27) by means of a zener diode (31) connected between the wires (27) and ground which prevents a potential induced in the wires (27) from the electrode (24) from exceeding the zener voltage of the diode (31).

Abstract: Charging, imaging, developing, transfer and cleaning units are operatively arranged about the circumference of a rotary photoconductive drum, the developing unit comprising a magnetic brush. A discharge unit is disposed between the transfer unit and the cleaning unit and comprises a light source and a corona discharge element to simultaneously illuminate the drum causing photoconduction and expose the drum to an electric field thereby neutralizing any residual charge on the drum and residual toner particles remaining on the drum after the transfer operation. The residual toner is subsequently removed by the magnetic brush of the developing unit.

Abstract: One or more rows of focussing optical fibers are disposed between an original document carrier and a photoconductive member. An illumination lamp illuminates an original document on the carrier and the fibers focus an image of a linear portion of the document onto the photoconductive member. Relative movement between the document carrier, fibers and photoconductive member perpendicular to the row or rows of fibers is produced to scan the document. An aperture assembly is provided between the fibers and the photoconductive member difining an aperture wide enough that unevenness of the intensity of the image on the photoconductive member due to the individual fibers is eliminated. The intensity of the light image is controlled by utilization of a variable transformer or triac provided to the illumination lamp.

Abstract: A transfer apparatus is provided of the type in which a toner image formed on a photosensitive member is transferred onto a transfer or copy sheet. The apparatus is used in a copying machine of a so-called delivery type in which the sheet is conveyed using a sheet gripper. During the transfer of a toner image, the appartus applies a corona discharge to the rear side of the sheet which is of the opposite polarity from that of the toner image. The apparatus comprises a diaphragm member for restricting an opening of a transfer charger and disposed between the transfer charger and the photosensitive member, the diaphragm member being movable away from the photosensitive member as the sheet gripper passes between the transfer charger and the photosensitive member.

Abstract: A magnetic developing process for use in electrophotographic or electrostatic recording techniques employs a magnetic brush formed by a developer which comprises a powder mixture of a low resistance toner and a high resistance toner, at least one of which comprises a magnetic toner. Both toners are triboelectrically charged, and the magnetic toner serves as a carrier, so that both toners are attracted to an electrostatic image to provide a developing thereof.

Abstract: A photoconductive drum has an image portion and a non-image portion. A biasing voltage is applied to a developing electrode when the image portion of the drum is adjacent thereto. The developing electrode is grounded when the non-image portion of the drum is adjacent thereto to prevent toner particles from being attracted thereto to accumulate and contaminate the developing electrode. A low voltage is applied to the non-image portion of the drum to remove toner from the developing electrode which was attracted thereto during development of the image portion of the drum.

Abstract: An improved developing device in electrophotographic copying apparatus in which a plurality of developing electrodes are disposed along a path of movement of a photosensitive drum surface. The electrodes are applied with voltages in a graded manner which conforms to the damping characteristic of the potential on the photosensitive surface at a developing station. The values of voltages applied can be controlled in accordance with the value of potential formed by an imaging area of the drum surface while maintaining the graded potential to thereby achieve an excellent developing effect. Further, the drum surface is provided with an unexposed and hence high potential portion which serves to remove toner which accumulates on the electrodes.

Abstract: An improved developing device in electrophotographic copying apparatus in which a plurality of developing electrodes are disposed along a path of movement of a photosensitive drum surface. The electrodes are applied with voltages in a graded manner which conforms to the damping characteristic of the potential on the photosensitive surface at a developing station. The values of voltages applied can be controlled in accordance with the value of potential formed by an imaging area of the drum surface while maintaining the graded potential to thereby achieve an excellent developing effect. Further, the drum surface is provided with an unexposed and hence high potential portion which serves to remove toner which accumulates on the electrodes.