Abstract: A photosensitive member for electrophotography comprises a first and a second photoconductive layer sequentially formed on a conductive layer. The first photoconductive layer has a spectral sensitivity extending over a range of light rays from ultraviolet rays to visible light. The second photoconductive layer is of light transmissibility, which is formed with a single or a compound layer and has a filtering action to transmit only light of longer wavelengths than a given one so as to define a range of light incident upon the first photoconductive layer, and a spectral sensitivity only to rays of shorter wavelengths than the given one.

Abstract: A duplicating system comprises an electrophotographic copier which includes a first document detecting switch, a first optical scanning system for making a slit exposure, a first document feeder for feeding a first document to be copied at a first speed with respect to the first optical scanning system, a rotating photosensitive drum for forming an electrostatic latent image corresponding to the image of document, and apparatus for forming a duplicated copy with the aid of the latent image. An option device is detachably mounted onto the copying apparatus and comprises a second document detecting switch, a second optical scanning system for making a slit exposure, a second document feeder for feeding a second document to be copied at a second speed with respect to the second optical scanning system and an optional optical system for projecting the image of the second document onto the photosensitive drum.

Abstract: An electrophotographic copying apparatus includes a charge retaining member carried by a conductive member and on which an electrostatic latent image is formed. The latent image is developed with toner, and the toner image is transferred onto a record sheet by transfer means connected to a transfer bias source which is connected between the conductive member and the ground so that its terminal of the same polarity as the polarity to which the toner is charged is connected to the conductive member. A corona charger is disposed in opposing relationship with the charge retaining member. A high tension source is provided to cause a corona discharge from the corona charger. The high tension source has its one terminal connected to the conductive member and its other terminal connected to a corona discharge wire of the corona charger.

Abstract: An electrophotographic copying process employs a photosensitive member which includes a conductive layer carrying a sequential lamination of a photoconductive layer which is sensitive to visible light and a function layer different therefrom, forms an electrostatic latent image by trapping charge on opposite sides of either of the photoconductive layer and the function layer in such a condition that a layer which is not retaining the charge is one of photoconductive layers forming the photosensitive member, and repeatedly employs the electrostatic latent image to produce a plurality of copies. During the copying step for producing a plurality of copies, a uniform exposure by light rays which activate the one of photosensitive layers forming the photosensitive member which is not retaining the charge is applied to the photosensitive member.

Abstract: A duplicating system comprises an electrophotographic copying apparatus which includes a first optical scanning system for making a slit exposure, a first document feeder for feeding a first document to be copied at a first speed with respect to the first optical scanning system, a rotating photosensitive drum for forming an electrostatic latent image corresponding to the image of document, and means for forming a duplicated copy with the aid of the latent image; and an option device detachably mounted onto the copying apparatus and comprising a second optical scanning system for making a slit exposure, a second document feeder for feeding a second document to be copied at a second speed with respect to the second optical scanning system and an optional optical system for projecting the image of second document onto the photosensitive drum.

Abstract: An electrophotographic apparatus for producing one or more copied images of an original by forming an electrostatic latent image of the original on a photosensitive member whose width is narrower than that of a recording paper, developing the latent image, and transferring the developed image onto the recording paper, the apparatus including a device for removing electric charge from edge portions of the photosensitive member after said transferring but before next succeeding development of said latent image in the course of repeating developments and transferrings of one electrostatic latent image formed on said photosensitive member.

Abstract: In a transfer roller for use in a retention type copying machine, a semiconductive transfer roller is connected through a current limiting resistor having a high resistance value of 100 M.OMEGA. to 1000 M.OMEGA. to a transferring bias voltage source. A pair of auxiliary transfer rollers made of conductive material are arranged on respective sides of the transfer roller. The auxiliary transfer rollers are connected to the transferring bias voltage source through a potentiometer. To the transfer roller is applied a first transferring bias voltage of 600 to 900 volts and to the auxiliary transfer rollers is applied a second transferring bias voltage of 400 to 650 volts. When a resistance of a record paper is decreased due to high humidity, the first transferring bias voltage is automatically decreased and the second transferring bias voltage becomes predominant.

Abstract: A conveyor unit for a book carrier includes a book carrier on which an original having substantial thickness such as a book is placed, and conveys it to an exposure station in order to form an electrostatic latent image of the original in a copying machine. A driven member in the form of a rack is formed on the book carrier, and is driven by a drive member in the form of a pinion which is provided on the part of the copying machine. Elements are provided to maintain such drive relationship. In this manner, a book carrier is positively and reliably conveyed.

Abstract: In a method for printing in an electrophotographic manner a number of duplicated copies by repeatedly effecting developing and transferring steps for the same and single electrostatic charge latent image once formed on a charge retentive member such as a photoconductive drum, in order to compensate a variation in print density of a number of copies an amount of toner particles to be supplied to the latent image during the developing step is adjusted in such a manner that the copies have substantially the same print density. The adjustment of an amount of toner particles can be effected by changing a supply speed of the toner particles, a thickness of a magnetic brush, a distance from the magnetic brush to the latent image, etc.

Abstract: An electrophotographic sensitizing screen having a great number of apertures, wherein at least an insulating layer and a conductive layer are successively formed on a conductive mesh, is disclosed. These apertures are regularly arranged at such an angle as not to produce moire fringes with respect to a light image projected on the screen.

Abstract: An electrophotographic copying apparatus comprises a photosensitive member which includes a conductive layer carrying a sequential lamination of a first photoconductive layer which is sensitive to visible light and a second photoconductive layer which is sensitive to ultraviolet rays and serves as an insulator to the visible light and a neutralizing unit for an irradiation of visible light and ultraviolet ray in order to neutralize charge on an area beyond image scope of the photosensitive member.

Abstract: An electrophotographic process for forming or printing one or more duplicated copies of an original document comprisesa step for subjecting a uniformly charged photosensitive member such as a photoconductive drum and a photoconductive screen drum to an imagewise exposure corresponding to an image of the document to be duplicated to form an electrostatic charge latent image corresponding to the image of the document;a step for developing the electrostatic charge latent image with a toner developer such as a magnetic brush by bringing it into contact with the latent image while applying a development bias voltage between the photosensitive member an a development electrode arranged at or near development means; anda step for transferring the developed toner image onto a record medium to form the duplicated image thereon, wherein the development bias voltage is manually changed to adjust a quality of the toner image such as density, contrast and half tone properties.

Abstract: An electrophotographic apparatus for printing or forming at least one copy of a manuscript comprising a manuscript feed mechanism including upper and lower side feed mechanisms arranged above and below a rectilinear manuscript feed path including a slit light exposure portion at which a manuscript image is projected onto a photosensitive drum, said upper side feed mechanism being movable with respect to said slit light exposure portion to define thin and thick manuscript feed paths, respectively. A thick manuscript feed mechanism is provided in the lower side feed mechanism for feeding a thick manuscript carriage made of transparent plate. The apparatus further comprises a first movable edge guide for positioning an edge of a sheet manuscript and a second fixedly arranged guide for positioning the edge of the thick manuscript carriage. The first guide is preferably positioned inwardly with respect to the second guide viewed in a widthwise direction of the manuscript.

Abstract: A developing unit comprises a guide vane mounted on a portion of the housing which defines a developing opening and disposed for contact with the free end of a developer brush which is formed by a conveying magnetic pole, and a vent formed in the housing at a location removed from the opening. The guide vane cooperates with the brush which moves during the rotation of a non-magnetic sleeve to provide an air pump action, which draws the air containing the toner in suspension into the closed housing of the developing unit from the region of the opening while the vent acts to reduce the internal air pressure within the housing which tends to increase as a result of the air pump action.

Abstract: A conveying apparatus includes a plurality of pairs of conveying rollers which are disposed for abutment against each other for transporting a copy sheet carrying an unfixed toner image thereon toward a fixing unit. A cleaning member is disposed for abutment against those rollers which are adapted to contact the toner image to clean them and to charge them triboelectrically to the same polarity as the toner.

Abstract: In an electrophotographic developing unit including a magnet roll to apply developer consisting of electrically-insulated magnetic toner particles to a latent image to be developed and an electrifying device to electrify the magnetic toner particles in one polarity, the disclosed automatic controller has a detecting electrode disposed where the magnet roll forms ear-ups of the developer, the detecting electrode receiving a bias voltage of the opposite polarity to that of the electric charge on the magnetic toner particles, a photocell cooperating with a light source in detecting the amount of toner particles attracted by the detecting electrode so as to produce a signal representing the thus detected amount, and a control circuit to control the electrifying device in response to the signal from the photocell.

Abstract: A duplicating system comprises an electrophotographic copier which includes a first optical scanning system for making a slit exposure, a first document feeder for feeding a first document to be copied at a first speed with respect to the first optical scanning system, a rotating photosensitive drum for forming an electrostatic latent image corresponding to the image of document, apparatus for forming a duplicated copy with the aid of the latent image and a sequence control circuit for controlling a duplicating operation in such a manner that the image of first document is projected onto the photosensitive drum from an imaginary control start position.

Abstract: A temperature controller for photographic heat fixing unit which may be used in an electrophotographic copying apparatus includes a main temperature for detecting the temperature of a heater or heaters in the fixing unit and an auxiliary temperature sensor for detecting the temperature of a marginal member spaced from the heater or of a record sheet. The temperature level of the fixing unit is controlled in accordance with outputs from the both temperature sensors.

Abstract: In an electrophotographic apparatus where charges retained on a photosensitive member, which is generally, photoconductive member, are discharged and erased by illuminating the light emitted from an illuminating device on the photosensitive member. The unnecessary charges retained on the portion of the photosensitive member other than the region corresponding to the image receiving medium are removed or erased with the light illumination by controlling on and off switching of the illuminating device.

Abstract: A magnetic roll developing device comprising a magnet for forming a developing main magnetic pole and divided into a plurality of magnet portions so as to form spaces therebetween and spacer members fitted in said spaces and forming weak magnets, the plurality of magnet portions forming a plurality of independent brush fur-like portions of the developing agent.