Abstract: A multi-layered electrophotographic element providing significantly improved properties, and especially so for use as a "permanent" master in transfer photocopying, comprises a conductive support carrying a photoconductive charge generating layer and on top of the photoconductive layer a charge transporting layer containing homogeneously distributed in an insulating binder a charge transporting agent selected from among certain azines which may comprise one or more alkylsubstituents and/or heterocyclic groups with at least one nitrogen atom and/or phenyl or naphthyl groups. The charge transporting layer may also contain to advantage an activator for the charge transporting agent. Particularly effective activators are terephthalal dimalonitrile (TDM) and 1,3,7- trinitro-dibenzothiophene-5,5-dioxide (DBTO). The charge transporting layer preferably is applied to a very thin charge generating layer formed on an endless support, and which contains the charge generating compound in molecularly divided form.

Abstract: In an image transfer apparatus comprising two separate image carrying media, such as endless belts, from one of which image information can be transferred to the other medium by temporarily holding the two media in frictional contact with one another, each of the media is advanced at constant or substantially constant speed by its own drive system; the drive system of a first medium comprises a feedback control system which controls the speed of that medium so that a measuring signal which is delivered by a measuring circuit and represents the measured speed of the first medium is equal to a reference signal delivered by a reference source; and during each transfer interval, when the two media are being advanced at the same speed under the frictional force of their contact with one another, the feedback control of the speed of the first medium is interrupted and an adjusting signal is produced by which the relationship of the measuring and reference signals is adjusted so that the speed of the first medium wi

Abstract: An inverter for reversing the direction of movement of sheets fed to it even at high speed comprises a guide member onto and along which a sheet is fed and having an end edge portion spaced a small distance from a bend-over guide that lies across and at an acute angle to the path of the leading edge of the sheet and deflects the leading edge so that a leading portion of the sheet is bent over the end edge portion to retard the sheet movement. The sheet then is in a position to be delivered by movement in the reverse direction. The bend-over guide typically is disposed at a distance of 3 to 10 mm from the end edge portion and at an acute angle of 60.degree. to 85.degree. to the adjacent surface of the guide member. Preferably, the guide member presents a concavely bowed sheet guiding surface having angled recesses extending across it.

Abstract: Electrophotographic copying by use of a machine in which a charge image is developed by the application of electrically conductive marking (toner) particles can be carried out so as to produce well imaged copies of low-contrast originals that contain weak image information by effecting the copying under conditions which cause the charge image to be developed with a grayish background of sparsely attracted particles and, during the developement, applying between an electrode of the developing device and the photoconductive element an a.c. voltage having a frequency of between 1 and 7 kHz and an amplitude of at least 50 volts, thereby rendering the background homogeneous in tone. In positive working processes, illumination that underexposes the element is used and only the a.c. voltage need be applied in development. In negative working processes, illumination that over-exposes the element is used and in development the a.c. voltage is superimposed onto a d.c.

Abstract: Toner powder the particles of which are composed of thermoplastic resin, coloring material and possibly other additives such as magnetically attractable material comprises as the principal resin a thermoplastic polymer containing in its molecule one or more each of mutually immiscible crystalline and amorphous polymeric blocks, the crystalline blocks forming the continuous phase in the polymer and having a melting point between 45.degree. and 90.degree. C. and the amorphous blocks having a Tg at least 10.degree. C. above the melting point of the crystalline blocks. The toner powder is especially beneficial for use in a method of transferring and fixing powder images in which an image formed of the powder is softened by heating it on a medium having less surface adhesivity for the softened powder than has the image receiving material and the softened powder on this medium is brought into pressure-contact with substantially unheated image receiving material.

Abstract: A copying machine control system employs a synchronous motor driven synchronously with an AC supply voltage to transport a surface on which an image is formed. At least one stepping motor is employed discontinuously to transport an original containing material to be copied at a speed which produces an image moving at the same speed as the surface where the image is formed. A stepping motor controller programs an acceleration profile for the stepping motor to permit it to be accelerated to running speed in a precisely defined manner so that the position of the original is always accurately known. The stepping motor controller derives its control pulses from the same AC voltage which drives the synchronous motor and thus, the original and the image surface are accurately driven in synchronism. A transport speed of the original is in inverse proportion to the imaging ratio.

Abstract: An amorphous silicon based photoconductive element for use in electrophotographic copying processes, which exhibits a suitably low dark discharge rate with other good photoelectric properties, is composed of an electrically conductive support having applied thereto, in sequence, a barrier layer consisting essentially of a doped hydrogen-containing amorphous silicon, an intermediate layer consisting essentially of substantially undoped hydrogen-containing amorphous silicon, an intermediate barrier layer consisting essentially of doped hydrogen-containing amorphous silicon and a main, charge receiving layer consisting essentially of substantially undoped hydrogen-containing amorphous silicon.

Abstract: An original holder or like device for bringing a sheet into a flat exposure plane in a reprographic apparatus comprises a transparent resilient support plate which normally is resiliently held slightly bowed and a rigid flat pressure plate such as a glass plate which can be pressed onto the convex side of the support plate to bring the support plate and a sheet resting on it into a flat position for exposure of the sheet.

Abstract: An axially displaceable rotary part is latched securely in a certain axial position relative to a concentric rotary part by a mechanism which includes latch means that are rotated with the concentric part and are displaceable radially relative to it by movements of a ring member so as to engage elements of the latch means with and disengage them from a latchable member of the axially displaceable part. At operating speeds of the system the latch means are urged to latching position by centrifugal force. Although applicable to various rotary mechanical systems, the mechanism is particularly useful as a component of a heavy duty cyclical centrifugal machine for latching the bottom valve member of the centrifugal basket in closed position during the loading and centrifuging stages of each centrifugal operating cycle.

Abstract: A light detector circuit is described in which the baseline level of the output signal of a light detector is stabilized by feeding back a control signal to an element that has a voltage variable resistance and is connected in series with the light detector across a voltage source. Several embodiments are shown. In one embodiment a differential amplifier circuit with an integrating feedback circuit is employed to establish a stabilized control voltage.

Abstract: An apparatus, such as in a copying machine, by which an original sheet and a light-sensitive sheet can be fed along separate feed paths toward and onto one another and then one upon another through a station for exposure of the light-sensitive sheet to a light image of the original sheet is provided with a control system, including a separating device disposed to act on the sheets passing from the exposure station, whereby after an exposure the original sheet can be led away from the light-sensitive sheet irrespective of the relative position of the sheets fed for the exposure. A detector sensing the leading edge of an original sheet in its own feed path, activates the control system which in turn puts the separating device into operation after the lapse of a period of time corresponding to the time of transport of the leading edge of the original sheet from the detector up to the separating device.

Abstract: Device for the conveying of sheets from each of a plurality of sheet piles via a partially common conveyor track. This track extends in vertical direction along superposed stock holders. Adjacent to the sheet delivery side a driven roller is stationarily arranged above each pile. Each of these rollers can function both as suction roller for separating sheets from a pile and as friction roller for conveying sheets in the common track. For separating sheets from a pile, each pile can be brought by pneumatic means into short contact with a driven roller then functioning as a suction roller. For conveying sheets in the common track, each roller cooperates with a pressure roller. After a sheet in the common track has been gripped between a driven roller and a pressure roller, the sucting action of that driven roller is interrupted.

Abstract: Pulses from a fixed-frequency pulse generator are counted in a pulse counter to produce a binary number. The binary number is employed to access successive memory addresses which contain data for producing drive pulses for a stepping motor. The memory contents are arranged so that the number of pulses from the pulse generator required to produce a drive pulse decreases during starting and increases during stopping so that smooth acceleration and deceleration of the stepping motor are achieved. In one embodiment, successive locations store "0" or "1" to produce a motor drive signal. In another embodiment, successive locations store numbers which control the length of time until the next drive signal is produced.

Abstract: Method for cleaning waste water, wherein the waste water (19) and oxygen gas (31) are flowing in opposite directions through a cylindrical multireactor (20) having a central rotatable pipe (24), the multireactor comprising a number of bioreactors and at least one separation chamber (75). The average pressure difference between two successive bioreactors is at most seven meter water column. The bioreactors are separated from each other by stationary walls (40, 41, 48, 55, 60), and each bioreactor has its own mixing device (50) for mixing waste water and oxygen gas.

Abstract: A windshield wiper blade holder for attachment to a wiper arm of the side mounting type comprises a primary yoke member having a rigid central portion formed with a socket extending transversely through it to receive a side pin on the end of the wiper arm, and formed in and along its under side with a recess having fitted thereinto a resilient latch member which is formed as a unitary molding of a tough polymeric material and is assembled simply by being pressed into the recess until protrusions at one end of the latch member are anchored in a pocket to one side of the socket. A block-like abutment portion of the latch member is held resiliently in a cavity across the socket so that the abutment portion can be displaced downward by an arm side pin thrust into the socket and then will engage in a groove of the side pin to couple the blade holder with the wiper arm.

Abstract: A rearview mirror positionable by remote control including a housing having a mirror that is held in an open side thereof and that is moveable to desired viewing positions. A plurality of mirror positioning rods displaceable longitudinally relative to the housing have their respective ends connected pivotally with the back of a plate that supports the mirror. Electric motors inside the housing are connected through a compact arrangement of speed reducing gears to drive transmission pinions for displacing each rod and for retaining the rod in adjusted position. Each pinion has a peripheral series of undulations held normally in meshed engagement with a series of undulations along a side of each rod to provide for displacement of the rod upon rotation of the pinion.

Abstract: A sensor senses the height of a stack of sheets in a magazine. The sensed height is scaled according to the thickness of individual sheets to determine the number of sheets available. At the start of a run of, for example, a copying machine, the number of sheets available is compared to the number of sheets required to complete the run and, if the number available is insufficient, an indication of this fact is given to the operator and an inhibit device may prevent operation of the copying machine. In one embodiment, a counter causes a sampling circuit to determine and display the number of sheets available at predetermined intervals, preferably at the beginning and end of each run.

Abstract: An exposure device for homogeneously exposing to light and thus discharging regions of a photoconductive imaging element located outside the regions thereof on which images are to be formed makes use of a lamp housing having a window for passing light to the element and masking member having a terminal edge extending obliquely relative to an axis of the window, and displaceable laterally relative thereto, for covering any desired portion of the area of the window. The masking member can be a tubular member surrounding and turnable about the housing and having a helical edge that can be disposed at any desired location over the window by turning the tubular member. The exposure device can be mounted over a moving photoconductive element such as a photoconductive belt or drum in oblique relation to the direction of movement of the element so that the terminal edge of the masking member will always be parallel to that direction.

Abstract: An apparatus for delivering web material or the like from rolls comprises a rotatable holder that holds a plurality of web supply rolls and for each roll is provided with a separate support member for supporting the free end of a portion of the web unwound from the roll. The roll holder is movable between a plurality of positions in each of which one of the supply rolls is in an active position at a location where a portion of its web can be unwound and transported over a cutting edge provided on the related support member, and where a cutting element separate from the holder can be operated to cut off a sheet of required length from the unwound material of the positioned supply roll by cooperation with the related cutting edge.