摘要:
An electrophotographic color proofing apparatus is provided including a copyboard carrying a color separated positive and capable of being positioned into intimate contact with a charged photoconductive coating of an electrophotographic member. The engaged members are exposed to light, discharging the coating in increments to form a latent electrostatic image thereon. The copyboard is withdrawn and the exposed electrophotographic member rotated 180 degrees facing toward a toning assembly consisting of a row of plural toning units, each carrying a different color toner and arranged in line for linear translation below the exposed electrophotographic member with a selected one toning unit thereof being activated to apply a selected color toner to the latent electrostatic image. The toned member again is revolved 180 degrees. A pre-wet transfer medium in the form of print paper stock is engaged with the toned member for transfer of the toned image, preferably by drawing a roller across said member while employing a simultaneous electrical bias. A full color proof can be obtained by repeating the cycle, activating successive individual toning units of the assembly and using the same sheet of transfer medium. Registry of plural images applied to a single sheet is effected mechanically, as by upstanding pins provided on the support for electrophotographic member and/or the copyboard. Provision is made to clean both the photoconductive surface and the bias plates of the toning units of excess and/or residual toner.
摘要:
A method and apparatus for developing a latent electrostatic image on the surface of an electrophotographic member using a liquid toner and a development electrode. An AC bias voltage is applied between the electrophotographic member and the development electrode during the developing operation to prevent the formation of spatially stable convection cells in the liquid toner.
摘要:
A printing method and apparatus in which an elongate substrate such as a strip of paper, fabric, synthetic resin sheeting, foil or the like is imprinted with a plurality of patterns in different colors to achieve a composite multicolored image.The apparatus has multiple independent stations through which the substrate is passed, each station having a master sleeve with an image in semipermanent fixed primary toner formed thereon. The image is transferred to the substrate directly from the sleeve or by way of an intermediate transfer roll or blanket as in offset printing.The master sleeve is charged in light, the toned parts retaining charge by virtue of being dielectric in character, the now charged image is toned with a suitable pigmented secondary toner and this double toned image is pressed against the passing substrate or brought very close to it either directly or through the transfer medium. Through the aid of an electrical field established between the substrate and the sleeve or transfer medium the toner is transferred to the substrate and the sleeve and medium circulate back to pass through the same process of charge, tone and transfer.The transferred images on the substrate are fixed between or during movement through stations. Information on image density may be fed back to the same or previous stations for change in the bias field conditions or other parameters.
摘要:
An attachment for a graphic art camera taking the place of the ordinary silver halide film cartridge for use in making a lithographic printing plate. The attachment includes an endless web mounted on rollers. At least a portion of the web is made of flexible electrophotographic film. The electrophotographic film is rotated past a charging station where the film is charged, an exposure station where a latent image is formed, a toning station where the latent image is toned with an ink-receptive toner, and a transfer station. At the transfer station the toned image is transferred from the film portion to a blank lithographic printing plate. The resulting plate is suitable for use in an offset printing press.
摘要:
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.
摘要:
A corona generating element in the form of a strand of metal wire having thin portions along its length at closely and regularly spaced intervals. When a source of high voltage is connected to the wire, a corona of high intensity is generated along the edges of each thin portion. The corona generating element is particularly useful in applying a uniform electrostatic charge of negative polarity to the surface of a photoconductive member.
摘要:
A method of toning the latent image carried by the photoconductive surface of an electrophotographic film in which a liquid suspension of toner particles is flowed or streamed substantially simultaneously uniformly against said surface over all said surface in a direction normal thereto from a source spaced from the surface and the excess or remanent toner suspension is removed from the surface thereafter without displacing said source or moving the film.The toner particles are biased with a d.c. bias voltage of a polarity the same as the electrophoretic surface charge of the toner particles to enhance particle movement toward the photoconductive surface.
摘要:
Method and apparatus for coating a thin film upon substrate means in a pressure vessel using the plasma vapor deposition technique known as sputtering. The substrate means are arranged on the exterior of a cylindrical drum for rotation and have the convex surface thereof exposed to the plasma vapor during rotation. An assembly of a plurality of circumferentially spaced arcuate target segments forming generally a cylinder is arranged coaxially and telescopically with respect to the drum whereby to form an annular belt of plasma vapor cloud segments occupying the gap exterior of the drum between the target means and the drum. The target means comprise the cathode of the high voltage electrical circuit and the drum comprises the anode.The projecting unit target area is larger than the unit exposed substrate area enabling radially converging plasma vapor and hence high rates of uniform coating.The drum may rotate the substrate means in the belt repeatedly or serve as transport means to bring the substrate means through the belt on one pass. The cylindrical belt is not closed but has a discontinuance which is somewhat greater than the distance between target segments. The substrate means are led onto the drum from the exterior of the assembly of target segments and likewise led off the drum and conveyed to the exterior of the assembly of target segments by way of such discontinuance.
摘要:
An electrophotographic film which is not only capable of being utilized for the same purposes as conventional xerographic and electrofax members but it also capable of being used in the same manner as silver halide emulsion photographic films, that is, with high speed cameras for universal photographic purposes.The electrophotographic film comprises a thin film coating of an inorganic, photoconductive, electronically anisotropic material one example of which is a specially sputtered cadmium sulfide bonded to a thin film layer of ohmic material which in turn is bonded to a thin, stable substrate member preferably formed of plastic sheeting. The total thickness of the photoconductive coating is about 3000 Angstroms, of the ohmic layer is about 500 Angstroms and of the substrate member is a fraction of a millimeter.The product is durable with a hard, abrasive-resistant surface, is highly transparent and flexible notwithstanding the fact that the photoconductive layer is crystalline, and has high photoelectric gain with sufficient speed and sensitivity to be used as mentioned in high speed photography. As such it can accept a charge at a rapid rate and will retain the same selectively after exposure to enable practical toning with an almost infinite gradation of pigment values, i.e., gray scale. The electrophotographic film which is made using the cadmium sulfide as the photoconductive coating has substantially panchromatic response.The photoconductive coating is novel and can be used in cases where its unusual characteristics provide functions other than required in the electrophotographic film. For example, the coating can be used in many places where it is not important that the entire assembly be transparent. It can be used on metal substrates in making economical circuit elements, for forming photosensitive devices, for making storage elements, in producing recording and transfer media and the like.Novel methods of manufacture and use of the electrophotographic film and the photoconductive coating are disclosed.
摘要:
Strip film of the conventional silver halide emulsion type is duplicated by optically projecting the images onto a high speed electrophotographic film in a system comprising a flow type camera having the original film and the electrophotographic film travelling at the identical film speed. The first station for the electrophotographic film is a charging station, followed by the projection slit, a toning station and a toner fixing station.The background density of the original film is measured by photometric means and compared with preset density standards, the resulting information being used to enhance the image produced on the electrophotographic film by varying the charge voltage level. Charge level will control the amount of toner which adheres for a given time of toning.