Abstract: An electronic signal representing the density of pixels in a scanned line in an original image and containing pixels in whole number multiples of a single line of halftone screen partial dot values plus a predetermined extension parameter is electronically halftoned by comparing the pictorial signal with the single line of halftone screen partial dot values to form an electronic halftone image. An electronic screen function represented by the single line of halftone screen values, produces automatically a rotated halftone screen at a predetermined angle to the original electronic image when the number of pixels in the input, scanned line of the original document is set equal to a whole number multiple of the number of partial-dot values plus a predetermined extension parameter. Under these conditions, the scanned input is automatically halftone screened electronically into halftone cells approximating a parallelogram and having said predetermined angle.

Abstract: A storage buffer for a moving web comprises a collection bin having a bottom triangular cavity, a top opening through which the web can be randomly dumped under the influence of gravity and a bottom opening through which the web is withdrawn from the collection bin on a first-in, first-out basis. The sloping bottom walls of the collection bin are provided with ridges to assure the maintenance of a gas bearing beneath the bottom-most layer of exiting web. Nozzles for directing pressurized gas into the collection bin are located on both sides of the web at the collection bin exit.

Abstract: An electrostatographic printing machine in which a plurality of transparencies are reproduced simultaneously on a common copy sheet.The printing machine utilizes a pair of slide projectors arranged so that they simultaneously project non-over-lapping light images of the transparencies onto the charged portion of the photoconductive member.

Abstract: An electrostatic voltmeter or electrometer which includes a probe sensor element for receiving electrostatic charge from a test surface whose potential level is desired to be measured. The probe is conditioned to receive both A.C. and D.C. signals which are amplified by a D.C. amplifier, with the A.C. signal from the probe being fed back to the D.C. amplifier to stabilize its output. In a preferred embodiment, a portion of the probe sensor element is periodically exposed to the test surface to impress the A.C. signal thereon which is utilized to correct the drift in the D.C. amplifier output.

Abstract: An electronic signal representing the density of a scanned image is electronically halftoned by combining the pictorial signal with a rectangular array of halftone screen values to form an electronic halftone image. The electronic screen function represented by the array of halftone screen values is rotated at variable angles to the original electronic image by defining a repetitive rectangular matrix representative of any predetermined halftone cell approximating a parallelogram and incorporating a shifting parameter for the repetitive rectangular matrix. An efficient, high speed, partial-dot halftoning technique is performed by indexing the screen function rectangular array, under the supervision of the shifting parameter, against the scanned image values for a realtime serial combination of the functional values.

Abstract: A variable speed, fixed wavelength magnetic imaging system is provided by generating a signal having a frequency proportional to the speed of a rotational recording member and using that signal to provide a recording frequency of fixed wavelength.

Abstract: An apparatus for stripwise viewing a document and for projecting an image thereof onto a moving imaging surface. The viewing apparatus includes at least one reflector having a reflecting surface and being arranged along an optical path. An illumination slit controls the projected illumination intensity. The slit is defined by at least one boundary configured in a desired profile. The reflecting surface of the reflector is delimited so that at least one boundary defined by the reflecting surface is configured in the desired slit profile, whereby the reflector and slit are arranged integrally together. A reproducing apparatus and a process for making the viewing apparatus also are claimed.

Abstract: An improved exposure slit system for controlling the projected image illumination profile of an optical system of a reproducing machine. The optical system is arranged to stripwise view a document. The exposure slit system includes one exposure slit member arranged near the object plane and a second exposure slit member arranged near the image plane. The exposure slit profile for controlling illumination at the image plane is comprised in part by the profile of the exposure slit member at the image plane and in part by the profile of the exposure slit member near the object plane as projected at the image plane.

Abstract: A multi-mode reproducing apparatus which includes means for copying documents selectively at a plurality of copy image magnifications. An imaging surface is arranged for movement at a given velocity. Optical elements are provided for viewing a document and for projecting an image thereof onto the moving imaging surface. The optical elements include a first stationary lens for projecting the image onto the surface at a first projected image magnification, and a second lens arranged for movement between a first stored position where it is inoperative and a second position where it is operative to project an image of the document onto the surface at a second projected image magnification different from the first magnification.

Abstract: A reproducing apparatus including an optical system for viewing an object such as a document and for projecting an image thereof onto a photosensitive surface selectively at a first copy image magnification or at a reduced copy image magnification. The optical system includes a lamp for illuminating the object. A margin illumination system is provided utilizing stray light derived from the lamp of the optics system for illuminating margin regions of the photosensitive surface to prevent their subsequent development. The margin illumination system is selectively operable in the reduction mode of operation.

Abstract: A reproducing apparatus for producing copies of a document selectively at one of a plurality of copy image magnifications by moving original exposure. A feeder advances the document past a viewing system selectively at one of a plurality of velocities corresponding to the copy image magnifications. An edge of the document is sensed as it is advanced by the feeder. Responsive to the sensing of the document edge exposure is initiated selectively after expiration of one of a plurality of time intervals corresponding to the copy image magnification and the velocities of document advancement. In accordance with an alternative embodiment the document feeder advances the document past a plurality of document viewing positions corresponding to different desired copy image magnifications and the time intervals correspond to the viewing position as well.

Abstract: A stack elevating apparatus for a sheet feeder. A tray for supporting a stack of sheets is arranged for movement between at least one elevated position and a lowered position. The tray is arranged to descend to the lower position by gravity. An inertial force is provided for controlling the rate of descent of the tray. In one embodiment the inertial force is provided by an inertial member which is arranged to rotate in response to the descent of the tray and for continued rotation after the tray has stopped. In another embodiment a system is provided for amplifying the inertial force provided by the inertial member. A selectively engageable friction drive system for elevating the tray forms yet another embodiment.

Abstract: A reproducing apparatus for producing copies of a document selectively at one of a plurality of copy image magnifications. A photosensitive surface is arranged for movement at a given velocity. A plurality of document viewing positions corresponding to different desired copy image magnifications are provided. The document is viewed in stripwise fashion selectively at one of the viewing positions, and an image thereof projected onto the photosensitive surface selectively at one of the plurality of magnifications corresponding to the viewing position selected.

Abstract: A reproducing apparatus including an imaging surface. A first frame supports a cleaning system for removing residual material from the imaging surface. A second frame supports a remote sump for storing the residual material removed by the cleaning system. The residual material is transported from the cleaning system to the remote sump through a selectively connectable conduit. One of the frames is supported for movement relative to the other between a first position wherein the conduit is connected between the cleaning system and the sump, and a second position wherein the conduit is disconnected. Preferably, a valve is provided in the conduit which is responsive to the movement of the frame for selectively sealing off the conduit when it is disconnected.

Abstract: A reproducing apparatus having a plurality of modes of operation. The apparatus includes a moving imaging surface. In a first mode of operation a stationary document is viewed and an image thereof is projected onto the imaging surface. In a second mode a document moving at a first speed synchronized to the speed of the moving imaging surface is viewed, and an image thereof is projected onto the imaging surface at a desired magnification. In a third mode a document moving at a second speed synchronized to the speed of the moving imaging surface is viewed and an image thereof is projected onto the surface at a reduced magnification. An arrangement for selecting the desired mode of operation is provided.

Abstract: An apparatus and process for cleaning the surface of an electrostatographic imaging member and an electrostatographic reproducing machine utilizing the cleaning apparatus. A device is provided for impinging a gas flow against the imaging surface for removing residual material therefrom and for applying suction to the surface to provide a suction flow for collecting the gas and the residual material and transporting them away from the imaging surface. Apparatus is provided for supporting the impingement device and the suction device close to the imaging surface including a device for forming a supporting gas cushion. In accordance with an alternative embodiment apparatus is provided for positioning the impingement and suction devices close to the imaging surface during operation of the cleaning system and away from the surface after the cleaning system has ceased to operate.

Abstract: A sensor arrangement is provided for sensing the position of an edge of a fed sheet adjacent a front stop. Timing circuitry responsive to the sensor arrangement is used to time a reference time interval from the sensing of the edge. The timing circuitry is coupled to a sheet feeder and is capable of stopping the sheet feeder upon the expiration of the reference time interval. The reference time interval is selected to be sufficiently long to allow the sheet feeder when feeding a sheet to form a buckle in the sheet. The reference time interval is adjustable to provide adjustability of the height of the buckle.

Abstract: A sheet distribution apparatus for distributing sheets discharged from a reproducing machine. An improved apparatus sequentially distributes sheets into a plurality of bins comprising sheet receiving shelves arranged in a horizontal array. A guide belt is arranged to receive the discharged sheets and guide them into the respective shelves. The guide belt is coiled upon a take-up reel at one end at its other end a device is provided for sequentially advancing the belt along the entrance openings of the bins to distribute the sheets into the respective bins.

Abstract: A reproducing apparatus and process for forming multiple copies of a document. The apparatus includes a moving photosensitive surface. The first copy of the document is formed while the document is moving in synchronism with the photosensitive surface and the second and further copies of the document are formed while the document is held stationary. The multiple copy mode of operation can be combined with other modes of operation such as reduction, a single copy mode and a large document copying mode, as desired, to provide an apparatus having substantial versatility.

Abstract: A reproducing machine including a device for forming an image of information on an original document and a device for transporting the document past the imaging device. The transport device comprises a strip member. The strip member supports the documents and moves past the imaging device to present the documents for forming an image thereof. The strip member may have a plurality of original document receiving pockets.