To Produce Multiple Image On Medium Or Plural Radiant Energy Exposures Of Medium, E.g., Image Intensification Using Two Images, Or Two Exposures Of Same Image, Etc. Patents (Class 430/54)
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Patent number: 4537490Abstract: Method and apparatus for electrophotographically producing high quality reproductions which contain different content types. Photoconductor image sectors are subjected to separate, component exposures selected for (1) good tone-scale reproduction of continuous-tone image portions and (2) high-contrast reproduction of line-type image portions. Photoconductor background areas, which border continuous-tone image portions, are exposed to a discharge level below the system's development level.Type: GrantFiled: June 4, 1984Date of Patent: August 27, 1985Assignee: Eastman Kodak CompanyInventor: Michael D. Stoudt
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Patent number: 4532197Abstract: A method of forming an image on an electrophotographic film material is described. This involves a contact printing technique and comprises the following steps:(a) placing an image-bearing master in contact with the film;(b) exposing the film to light through the image-bearing master, the exposure being substantially greater than the minimum necessary to render conductive the photo-conductive layer of the electrophotographic film;(c) applying a substantially uniform charge to the surface of the film in the dark immediately after exposure;(d) leaving the film in the dark for a short time so as to allow the charge to migrate selectively; and(e) then developing the image.Type: GrantFiled: May 17, 1983Date of Patent: July 30, 1985Assignee: Comtech Research Unit LimitedInventors: Victor C. Humberstone, John H. Fisher
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Patent number: 4522904Abstract: In the specific embodiments described herein, the charge drop resulting from fatigue in an electrophotographic process using an a-Se:H photosensitive member is reduced by a stabilization exposure carried out for one to three cycles prior to use of the member for image formation. Longer wavelength light may be used for the stabilization exposure and shorter wavelength light may be used for the imaging and discharge steps.Type: GrantFiled: September 23, 1982Date of Patent: June 11, 1985Assignees: Fuji Electric Company, Ltd., Fuji Electric Corporate Research & Development, Ltd.Inventors: Hideki Kina, Toshiyuji Iijima, Eizo Tanabe, Toyoki Kazama, Masaharu Namba
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Patent number: 4518668Abstract: A method for preparing a lithographic printing plate is disclosed. The method involves providing a light-sensitive material comprised of an electroconductive support having a hydrophilic surface. The surface has provided thereon a light-sensitive layer and a photo-conductive insulating layer which may be provided in that order or combined in a single layer. The material is imagewise exposed and then subjected to electrophotographic processing to form an electrostatic latent image on the photoconductive insulating layer. After exposure the electrostatic latent image is developed with developer particles which are opaque to the light to which the light-sensitive layer is sensitive in the presence of an electrode facing the photoconductive insulating layer. The development is carried out while applying a bias voltage between the electrode and the light-sensitive layer so that residual charge on the non-latent image areas appears zero.Type: GrantFiled: March 24, 1983Date of Patent: May 21, 1985Assignee: Fuji Photo Film Co., Ltd.Inventor: Takao Nakayama
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Patent number: 4500587Abstract: The present invention relates to a graphic arts film obtained by forming a toner image on a light-transmitting base sheet having a toner-adhesive and ink-repellent coating layer, then fixing the toner image and applying ink onto the surface of the base sheet to thereby selectively enhance the optical density of the toner image area on the coating layer, and a method of preparing the same.The present invention permits easy and inexpensive production of a graphic arts film having a sufficiently enhanced optical density, free from pin-holes and capable of being retouched with respect to the image formed thereon.Type: GrantFiled: October 12, 1982Date of Patent: February 19, 1985Assignee: Toray Industries, IncorporatedInventors: Tadami Kamaishi, Takao Kitagawa
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Patent number: 4494856Abstract: An electrophotographic method and apparatus is disclosed which is able to faithfully reproduce the half-tone portion of an original image on a photosensitive medium having an electroconductive layer, a photoconductive layer and an insulating surface layer. The present invention is directed particularly to improvements in the secondary charging step in the above method. According to the invention, the process of secondary charge includes the steps of subjecting the photosensitive medium to the action of corona discharge having the component of opposite polarity to that of the primary charge with simultaneous light image exposure, exposing the photosensitive medium surface to a light image while reducing or stopping the action of corona discharge and exposing the photosensitive medium surface to a light image while controlling the amount of corona discharge.Type: GrantFiled: August 20, 1982Date of Patent: January 22, 1985Assignee: Canon Kabushiki KaishaInventors: Takao Aoki, Takahiro Inoue, Masahiro Goto, Kenji Takeda
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Patent number: 4477549Abstract: A highly sensitive photoreceptor for electrophotography that forms a sharp image during repeated use is disclosed. It comprises an electrically conductive support having successively formed thereon a photoconductive photosensitive layer and a protective layer for that photosensitive layer, said photosensitive layer comprising an organic photoconductive material and said protective layer comprising an amorphous silicon carbide or amorphous silicon nitride containing a hydrogen atom and/or a fluorine atom. A method of forming a latent electrostatic image and an electrophotographic process using such photoreceptor are also disclosed.Type: GrantFiled: September 24, 1982Date of Patent: October 16, 1984Assignee: Konishiroku Photo Industry Co., Ltd.Inventors: Yoshihide Fujimaki, Yoshiaki Takei, Hiroyuki Nomori
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Patent number: 4472047Abstract: Method and apparatus for electrophotographically producing high quality reproductions which contain different content types. Photoconductor image sectors are subjected to separate, component exposures selected for (1) good tone-scale reproduction of continuous-tone image portions and (2) high-contrast reproduction of line-type image portions. Photoconductor background areas, which border continuous-tone image portions, are exposed to a discharge level below the system's development level.Type: GrantFiled: May 12, 1983Date of Patent: September 18, 1984Assignee: Eastman Kodak CompanyInventor: Michael D. Stoudt
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Patent number: 4469767Abstract: This invention provides a process for making image overlay through the steps constituting an electrophotographic process, and also an apparatus adapted for conducting such process. The process, based on an electrophotographic process utilizing a three-layered photosensitive member having an insulating cover layer, comprising exposing the photosensitive member to a first image-forming irradiation to be overlaid substantially simultaneously with or subsequent to a charging on the surface of the insulating layer, then exposing the photosensitive member to a second image-forming irradiation to be overlaid substantially simultaneously with an AC or DC corona discharge given to the photosensitive member, and subsequently giving a uniform exposure to the surface of said photosensitive member thereby obtaining an electrophotographic overlay image of the first and second irradiations.Type: GrantFiled: January 15, 1982Date of Patent: September 4, 1984Assignee: Canon Kabushiki KaishaInventors: Takashi Kitamura, Michio Ito
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Patent number: 4465749Abstract: A method for amplifying an electrostatic, charge-differential pattern is disclosed. The method comprises (a) imagewise forming a first toner deposit by developing a first electrostatic pattern having a first charge differential per unit area whose maximum value is no greater than a preselected level, (b) in an image-amplification element comprising a charge-holding surface layer overlying a field-supporting electrode, forming a current-carrying path between the toner deposit and the field-supporting electrode, (c) under conditions in which nontoned regions are not photoexcited, overall charging the image-amplification element with sufficient charge to form an enhanced electrostatic charge pattern having a second charge differential per unit area whose maximum value is greater than the preselected value in step (a), and (d) developing the enhanced charge pattern into a second toner deposit.Type: GrantFiled: June 20, 1983Date of Patent: August 14, 1984Assignee: Eastman Kodak CompanyInventors: John W. May, Yee S. Ng
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Patent number: 4464449Abstract: A method of recording information by projecting electromagnetic radiation to a recording medium, wherein a first electromagnetic radiation in a wavelength region to which the recording medium has its principal sensitivity is uniformly imparted to the recording medium, and, while the hysteresis remains, a second electromagnetic radiation a wavelength longer than said first wavelength region and which bears thereon the information to be recorded is projected onto the recording medium, thereby increasing the sensitivity of said recording medium with respect to said second electromagnetic radiation.Type: GrantFiled: January 29, 1982Date of Patent: August 7, 1984Assignee: Canon Kabushiki KaishaInventors: Isamu Kajita, Fumio Sumino
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Patent number: 4457993Abstract: An electrophotographic process for forming a given number of copies of an original once formed on a photosensitive member including a conductive drum, a photoconductive layer applied on the drum and an insulating layer applied on the photoconductive layer. The photosensitive member is first subjected simultaneously to a uniform exposure and a primary charging in one polarity, and then is subjected simultaneously to an imagewise exposure and a secondary A.C. charging. Next, the photosensitive member is subjected to a secondary uniform exposure with a reduced light intensity to such an extent that the charge image has an electrostatic contrast which is about 60 to 90 percent of the maximum attainable value. During the formation of copies by repeated development and transfer, the photosensitive member is subjected to an additional uniform exposure to restore the deterorated charge image.Type: GrantFiled: September 27, 1982Date of Patent: July 3, 1984Assignee: Olympus Optical Company LimitedInventor: Masaji Nishikawa
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Patent number: 4444859Abstract: An electrophotographic process for forming an electrostatic latent image in a photosensitive member. The photosensitive member is formed by applying, on a transparent conductive substrate, a transparent insulating layer and a photoconductive layer, which photoconductive layer is composed of a charge transfer layer and charge generation layers applied on both surfaces of the charge transfer layer. The charge transfer layer has a high mobility for charges of positive polarity. At first, the photosensitive member is negatively charged, while the member is uniformly irradiated from the side of the substrate. Then the photosensitive member is positively charged, while the member is exposed to a positive image of a document from the side of the photoconductive layer. Finally, the photosensitive member is exposed to a negative image of the document from the side of the photoconductive layer to form the electrostatic latent image from charges trapped across the insulating layer.Type: GrantFiled: May 27, 1982Date of Patent: April 24, 1984Assignee: Olympus Optical Company LimitedInventor: Yoshiyuki Mimura
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Patent number: 4411973Abstract: Radiation is directed toward a support through an ordered array of lateral walls to form interlaid radiation-exposed and shadowed microareas on the support. A first composition is then located on the support in either the shadowed or unshadowed microareas. At least one additional composition is then positioned on the support in laterally displaced microareas forming an interlaid pattern with the first microareas.Type: GrantFiled: August 17, 1981Date of Patent: October 25, 1983Assignee: Eastman Kodak CompanyInventors: Hugh S. A. Gilmour, Richard N. Blazey
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Patent number: 4407918Abstract: A photosensitive member is formed by applying on an electrically conductive substrate, a first photoconductive layer sensitive to a visible light, an insulating charge retentive layer, and a second photoconductive layer sensitive to ultraviolet light, successively in this order. At first the photosensitive member is uniformly charged to a negative polarity, while the photosensitive member is uniformly exposed to the visible light. Then an image of a document to be copied is projected while the photosensitive member is charged to a positive polarity. After that the photosensitive layer is uniformly exposed to the visible light and finally the photosensitive member is uniformly exposed to the ultraviolet light. In this manner, an electrostatic charge image having high contrast and resolution is formed in the photosensitive member by means of charges which are stably trapped across the charge retentive layer.Type: GrantFiled: February 16, 1982Date of Patent: October 4, 1983Assignee: Olympus Optical Company LimitedInventor: Eiichi Sato
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Patent number: 4392737Abstract: 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.Type: GrantFiled: November 23, 1981Date of Patent: July 12, 1983Assignee: Olympus Optical Co. Ltd.Inventor: Masaji Nishikawa
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Patent number: 4370398Abstract: A photoconductive member (21) is provided with inner (21b) and outer (21c) photoconductive layers. An electrostatic charge is formed at the interface of the layers (21b), (21c), either by a combination of applied charge and semiconductive current flow through the inner layer (21b) or applied charge and radiation with light having a wavelength selected to render only one of the inner (21b) and outer (21c) layers conductive. Then, the member (21) is radiated with a light image of an original document (26) to form an electrostatic image at the interface. The electrostatic image is repeatedly developed and the resulting toner images transferred to copy sheets (34). Another charge may be applied to the member (21) after the first charge to form electrostatic dipoles across the layers (21b), (21c).Type: GrantFiled: April 18, 1980Date of Patent: January 25, 1983Assignee: Ricoh Company, Ltd.Inventor: Tsutomu Sato
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Patent number: 4366220Abstract: An image-forming method suitable particularly for copying using image exposure wavelengths of 700 to 850 nm such as are experienced with semiconductor laser beam printers. Useful photosensitive members include photoconductive layer prepared from a dispersion of a photoconductive material including at least cadmium sulfide in a resin binder. The photosensitive member is sequentially subjected to a plurality of prehysteresis operations, each comprising electrostatically charging the member and uniformly exposing the same to light until the photosensitivity of the photosensitive member has been substantially stabilized.Type: GrantFiled: March 20, 1981Date of Patent: December 28, 1982Assignee: Minolta Camera Kabushiki KaishaInventor: Itaru Saito
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Patent number: 4358520Abstract: In the process of forming an electrostatic latent image on a photosensitive medium through at least two kinds of charging steps, the electrostatic latent image is stabilized by the steps of measuring the dark region potential V.sub.D and the light region potential V.sub.L on the photosensitive medium, comparing the measurement values with a predetermined referential dark region potential V.sub.DR and a predetermined referential light region potential V.sub.LR, and when the differences between the V.sub.D, V.sub.L and the V.sub.DR, V.sub.LR are not within predetermined ranges, setting the amount of control by control functions f(x,y) and g(x,y), in which the differences x=V.sub.DR -V.sub.D and y=V.sub.LR -V.sub.L are variables, and varying the potential of the latent image on the photosensitive medium in accordance with the set amount of control.Type: GrantFiled: March 23, 1979Date of Patent: November 9, 1982Assignee: Canon Kabushiki KaishaInventor: Kazuhiro Hirayama
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Patent number: 4355882Abstract: A multi-mode copying or reproduction apparatus. The apparatus includes a movable, overlong flexible photoconductive belt having image exposure, developing, transfer and cleaning stations operatively disposed about the belt circumference. A two chamber vacuum tensioner is used to collect the extraneous belt length. A raster scanner capable of both writing and reading images on the belt segment laying between the vacuum chambers is provided, together with an auxiliary belt driver for moving the aforementioned belt segment at a speed compatible with that of the raster scanner. An auxiliary charging device, and operators for disengaging selected xerographic components permit selective processing of images written or read by the raster scanner.Type: GrantFiled: February 26, 1981Date of Patent: October 26, 1982Assignee: Xerox CorporationInventor: Christopher Snellling
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Patent number: 4346982Abstract: An electrophotographic recording device suitable for a Form Overlay System, by which a latent image is formed on a surface of a light-sensitive recording medium, consisting of a first area which is maintained at an original potential, a second area which is maintained at a partially reduced potential and a third area which is maintained at a potential of zero.Type: GrantFiled: April 11, 1980Date of Patent: August 31, 1982Assignee: Fujitsu LimitedInventors: Junzo Nakajima, Masayuki Hida, Masakatsu Horie
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Patent number: 4345012Abstract: Electrostatic charge images of identical shape but opposite sign are generated on both sides of a transparent, highly insulating foil. Subsequently, pigment is deposited on both sides of the foil by means of oppositely charged developers. The optical density of an electrophotographic image on a transparent insulating foil is increased, as compared to densities achieved in the past, for a given surface charge density by establishing a charge exchange between one side of the foil and an electrode. On the other side of the foil a charge image is generated and the foil. The electrode are separated from each other prior to development.Type: GrantFiled: February 25, 1980Date of Patent: August 17, 1982Assignee: U.S. Philips CorporationInventors: Hans J. Hirsch, Horst Dannert
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Patent number: 4340657Abstract: Photopolymerizable compositions comprised of (I) novel polymers which are substantially comprised of the reaction products of (A) organic polyisocyanates and (B) organic compounds containing at least about two active hydrogen atoms per molecule, said polymers having been end-capped by reaction with (C) organic compounds containing exactly one active hydrogen atoms and said end-capped polymers having viscosities of from about 5 to about 70 stokes when measured as a 30% solution in a mixture of approximately equal parts of xylol, methyl ethyl ketone and ethylene glycol monomethyl ether, at 25.degree. C., (II) addition polymerization initiators activatable by actinic light, (III) addition polymerizable ethylenically unsaturated components capable of forming polymers by photoinitiated polymerization in the presence of the initiators, and (IV) a natural or synthetic rubber.Type: GrantFiled: March 9, 1981Date of Patent: July 20, 1982Assignee: Polychrome CorporationInventor: William Rowe
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Patent number: 4329413Abstract: The present invention is directed to process and apparatus for overlaying images making use of steps constituting a known electrophotographic process. The electrophotographic process on which the present overlay process depends is of the type in which a three-layered photosensitive member having an insulating covering layer as the top layer of the member is used. The surface of the insulating layer is charged with an electric charge simultaneously with an imagewise irradiation for a first image to be overlaid or during the time of a photo hysteresis resulted from the first image-forming irradiation being still present in the photoconductive layer of the photosensitive member. Then, AC discharging or charging with an electric charge of opposite polarity to that of the above electric charge is effected. Thereafter, an imagewise irradiation for second image is carried out to obtain an electrophotographically overlaid image from the first and second images.Type: GrantFiled: February 15, 1980Date of Patent: May 11, 1982Assignee: Canon Kabushiki KaishaInventors: Takashi Kitamura, Michio Ito
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Patent number: 4311778Abstract: This specification discloses an electrophotographic method and apparatus for forming an electrostatic latent image on a photosensitive medium having a conductive layer, a photoconductive layer and an insulating layer. The method comprises a primary charging step, an image light exposure step, a secondary charging step, a tone regulating step and a whole surface exposure step.Type: GrantFiled: June 27, 1978Date of Patent: January 19, 1982Assignee: Canon Kabushiki KaishaInventors: Hidejiro Kadowaki, Yasuhide Kurosaki, Takao Aoki, Naoki Iwami
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Patent number: 4308327Abstract: A motion picture film having a plurality of digitally coded soundtracks which are colorless and transparent to visible light and which fluoresce when exposed to ultraviolet light, unexposed film for providing the product, and the method for producing the product and methods for producing the exposed and unexposed films. The soundtrack images which overlie at least a portion of the visible image area of the film are digitally coded on the film using an electrostatic imaging system to imprint a fluorescent toner. The toner may comprise a fluorescent polymer having covalently bonded 3-phenyl-7-(amido or imido)-coumarin or certain substituted stilbenes or N-alkyl-4-aminonaphalimides.Type: GrantFiled: October 26, 1979Date of Patent: December 29, 1981Inventors: George Bird, Peter A. Custer
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Patent number: 4307165Abstract: A planar array of microcells is formed in a support. An electrostatic charge pattern is established on the support differentiating first and second interlaid sets of microcells. An electrographic imaging composition is introduced into the first set of microcells, and a second, differing imaging composition is introduced into the second set of microcells. Multicolor photographic elements, particularly dye image transfer photographic elements, can be prepared.Type: GrantFiled: October 2, 1980Date of Patent: December 22, 1981Assignee: Eastman Kodak CompanyInventors: Richard N. Blazey, Peter S. Alexandrovich, Domenic Santilli, Michael W. Mosehauer
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Patent number: 4297422Abstract: An electrophotographic process for printing a number of copies from a single electrostatic charge latent image once formed on a photosensitive member by projecting an optical image of a document to be copied comprises the following successive steps;(a) a step for effecting a uniform primary electrification with one polarity for the photosensitive member;(b) a step for forming on the uniformly charged photosensitive member, a primary electrostatic latent image corresponding to the image of the document by projecting the document image to the photosensitive member;(c) a step for developing the primary latent image with opaque toner particles having charged in the other polarity to form on the photosensitive member a toned image;(d) a step for placing a transfer member over a surface of the photosensitive member on which surface the toned image has been formed;(e) a step for effecting a secondary electrification with the one polarity from a side of the transfer member and for effecting a secondary exposure alsoType: GrantFiled: July 18, 1978Date of Patent: October 27, 1981Assignee: Olympus Optical Company LimitedInventor: Eiichi Sato
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Patent number: 4297423Abstract: An electrophotographic process comprising uniformly charging a composite photosensitive body with a charging polarity exhibiting a response property to a visible light, said composite photosensitive body being composed of a photoconductive semiconductor for producing carrier when illuminated by the visible light and a light transmitting organic photosemiconductor superimposed one upon the other, illuminating the charged composite photosensitive body with a light image by the visible light and producing thereon a first electrostatic latent image and producing thereon a second electrostatic latent image based on said first electrostatic latent image, said second electrostatic latent image having a polarity which is opposite to said charging polarity.Type: GrantFiled: November 24, 1978Date of Patent: October 27, 1981Assignee: Olympus Optical Company LimitedInventor: Masaji Nishikawa
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Patent number: 4291109Abstract: Disclosed herein is a method and apparatus for producing color transparencies on a recording element comprising an additive color filter screen having disposed thereon a coating of a visible light-transmissive, invisible light-sensitive, silverless material, preferably a diazo or vesicular material. The method comprises the steps of imagewise exposing a panchromatic auxiliary layer, e.g. a photoconductive layer, to a multicolored object, such exposure being made through the recording element of the invention. This step acts to produce in the auxiliary layer a monochrome image containing color image information of the multicolored object. Next, the silverless material is exposed to invisible actinic radiation, such exposure being made through the monochrome image formed in or on the panchromatic auxiliary layer. This step serves to transfer the color image information from the auxiliary layer to the silverless layer of the recording element.Type: GrantFiled: November 26, 1979Date of Patent: September 22, 1981Assignee: Eastman Kodak CompanyInventor: Keith E. Whitmore
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Patent number: 4288514Abstract: A photosensitive member is exposed to light prior to primary charging so that the surface potential applied by primary charging may always be maintained at a constant level to which the photosensitive member is always charged when it is repetitively used for some time, which may be predetermined by test. Until the surface potential reaches this level, the intensity of light for pre-exposure is gradually decreased and after the surface potential has reached this level, no pre-exposure is applied. But when the surface potential rises after a predeterminable period during which the photosensitive member is not used, the pre-exposure is applied again. All the copies may have the same density.Type: GrantFiled: September 7, 1977Date of Patent: September 8, 1981Assignee: Canon Kabushiki KaishaInventors: Noboru Kutsuwada, Minoru Saito, Ryoichi Namiki, Katsuo Kusunoki
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Patent number: 4287278Abstract: A method for forming an electrostatic latent image on an image recording medium includes forming a primary electrostatic latent image on a screen-type photosensitive plate, forming a secondary electrostatic latent image on the image recording material by irradiating the same with a charged particle current passed through the screen-type plate carrying the primary latent image, and correcting the secondary latent image on the recording material by irradiating the same with a charged particle current passed through the screen-type plate carrying the primary latent image.Type: GrantFiled: March 21, 1980Date of Patent: September 1, 1981Assignee: Konishiroku Photo Industry Co., Ltd.Inventors: Tatsuo Ohta, Sohji Shinozaki, Syusaku Yoshida, Hideo Ohba
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Patent number: 4273844Abstract: A heat-developable photosensitive member for forming an electric printing master comprises a support, an organic silver salt layer containing an organic silver salt, a halide and a toning agent dispersed in a binder, and a surface protecting layer or a particular surface, and a reducing agent is contained in at least one layer of the organic silver salt layer and a layer adjacent to the organic layer.Type: GrantFiled: August 9, 1978Date of Patent: June 16, 1981Assignee: Canon Kabushiki KaishaInventors: Hajime Kobayashi, Yasuhiro Yano, Ichiro Endo
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Patent number: 4264183Abstract: The duplex copying of two-sided originals onto two sides of a copy sheet is accomplished by interspersing images from two successive documents on a multi-image imaging member, specifically with the front-side image of a second document interspersed between the front and rear-side images of a first document. Copy sheet turnover can thus occur during the transfer of the front-side of the second document to achieve an increased "copy-output-rate to electrographic-procedure-speed" ratio.Type: GrantFiled: June 4, 1979Date of Patent: April 28, 1981Assignee: Eastman Kodak CompanyInventor: Michael D. Stoudt
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Patent number: 4259424Abstract: An improved heat-developable photosensitive material is disclosed which comprises an infrared rays-absorbing layer provided in contact with or adjacent to a layer comprising a reducible organic silver salt.Type: GrantFiled: February 5, 1979Date of Patent: March 31, 1981Assignee: Canon Kabushiki KaishaInventors: Ichiro Endo, Hajime Kobayashi, Toshiyuki Komatsu, Shigeru Ohno
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Patent number: 4256820Abstract: My invention comprises an improved method of electrophotography which enables me to increase the effective speed of a photoconductor. The speed at which copies may be made is a function of the quantum of light falling on the photoconductive surface and the conductivity of the photoconductor under illumination. Since the rate at which a given photoconductor discharges the surface potential on the photoconductor through the action of light is limited, speed can be increased for a given photoconductor only by increasing the illumination. This requires energy and produces heat. My process deliberately underexposes a charged photoconductor to a light and shade image of the original to produce a weak latent electrostatic image of low contrast which is insufficient to make a satisfactory copy. I then mask the latent image with a liquid-carried toner while preventing deposition of the toner on the background areas. I then discharge the background areas with a blanket illumination of low intensity.Type: GrantFiled: November 26, 1979Date of Patent: March 17, 1981Assignee: Savin CorporationInventor: Benzion Landa
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Patent number: 4241160Abstract: A method for obtaining multiple copies from apparatus including an electrophotographic member of the type in which the latent image is represented by charge not removed when toner is applied and thereafter transferred. The electrophotographic member with its latent image is repeatedly subjected to toning and transfer to respective multiple receptors without intervening charge and exposure. This may be done until the desired number of copies is made or until the image quality deteriorates by reason of dark decay. If additional copies are desired the electrophotographic member is again charged and exposed and thereafter toned and the image transferred repeatedly without intervening additional charge and exposure.Apparatus for effecting the method above and providing structure for carrying out the described steps include other functions such as automatically sensing quality and responding to a condition which requires a new cycle of charge and expose.Type: GrantFiled: May 25, 1978Date of Patent: December 23, 1980Assignee: Coulter Systems CorporationInventor: Manfred R. Kuehnle
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Patent number: 4219271Abstract: Disclosed is an image forming apparatus of a type, in which there is provided first and second electrically chargeable members, a first processing device to form a primary electrostatic latent image on the first chargeable member, a second processing device to form a secondary electrostatic latent image of the second chargeable member in accordance with the primary electrostatic latent image, to develop the secondary electrostatic latent image, and to transfer the thus developed image onto an image transfer material. A detecting device is provided to detect the visible image forming capability of at least one of electrostatic latent images; and, a control device is provided, responsive to the detecting device, to control at least one of the first and second processing devices so as to form a developed image of a predetermined image density.Type: GrantFiled: March 22, 1978Date of Patent: August 26, 1980Assignee: Canon Kabushiki KaishaInventors: Masharu Ohkubo, Yujiro Ando, Toshio Honma, Shuji Murakawa, Katsumi Murakami, Katsushi Furuichi