Abstract: An automotive seat belt retractor accessory frame is provided with a journal groove on one side which is engageable with one end of a structural pocket formed in an automobile for receiving the retractor. On the other side of the retractor frame and away from the journal groove is a stop usually formed as an integral extension of the flanges of the retractor frame. The stop is buttress engaging another edge of the pocket or opening and as the retractor frame is tilted into the pocket journalled at the groove and against one edge of the pocket, the retractor frame is stopped from further swing. A latch member secured to the retractor ramped to open upon passing engagement with the edge of the pocket and closes after the edge of the pocket has engaged the stop. The latch element, upon closing, is locked and the frame cannot be removed until a selected manual bias is applied through the pocket for release of the frame.

Abstract: A main frame for a vehicle constructed from a minimum number of parts is disclosed herein. The frame includes a pair of spaced elongated rectangular flat plates that have opposite edges and opposite ends interconnected by reinforcing plates and have aligned openings intermediate opposite ends thereof. Further reinforcing plates are located between the elongated flat plates and surround each of the openings and the various plates are arranged so that localized stress concentration areas are substantially eliminated.

Abstract: A novel casing torque hanger means for supporting the upper end of a string of casing from the upper end of a riser pipe which is supported by a floating vessel such as a Vertically Moored Platform. It includes a cylindrical member having a torque resistant spool below a casing hanger bowl. The casing string to be supported is provided with a casinghead mandrel at its upper end for engaging said torque resistant spool.

Abstract: A panic exit latch and actuator mechanism includes an elongated latch bolt actuator element rectilinearly movable along its axis and disposed in an elongated horizontally extending housing traversing a door. A push plate is supported for movement outwardly and inwardly relative to the housing. A pair of bell cranks provide an operative connection between the push plate and the actuator element to move the actuator element from its latch projected position to its latch retracted position in response to inward movement of the push plate. The bell cranks are mounted for pivotal movement about their apices in the housing, one crank being mounted adjacent either end of the housing. The pivotal axes of the bell cranks extend generally transversely to the direction of motion of the latch bolt actuator element. Each bell crank includes an arm pivotally connected to the latch bolt actuator element and arm pivotally connected to the push plate.

Abstract: The bolt of a latching mechanism is spring actuated toward a latching position relative to the latch-receptive slot of a latch-catch which is pivotally mounted on the vertical member of a swing gate, and movement of the bolt from a fully latched position to a retracted non-latching position is controlled by a pendulum stop which is normally and gravitationally disposed in interfering relationship with the bolt, whereby an intentional, deliberate, pendulum-stop-displacing action is required on the part of an attendant in order to enable the bolt to be shifted from an advanced, locked position to a retracted position.

Abstract: The invention relates to an arrangement of a visual shield in the form of an apron bridging the space between an impact receiving member and the end of a vehicle body frame to conceal the mechanical structure. The impact receiving member is located a considerable distance from the end of the vehicle body frame and secured to shock absorbers mounted to the vehicle body frame. An elastomeric spacer is disposed between the visual shield and the impact receiving member so as to prevent direct contact of the visual shield with the impact receiving member.

Abstract: Apparatus for applying a soft contact lens to the surface of an eye is disclosed to include a thimble section, a cup section and a stem section therebetween. The soft contact lens is retained on the cup section by capillary attraction during placement. The diameter of the cup section is less than the diameter of the lens being placed in order to cause the capillary attraction between the cup section and lens section to be less than the capillary attraction between the lens and the surface of the eye thereby permitting sure and easy placement.

Abstract: A collapsible camper includes a base having a floor and enclosing wall panels as well as a rigid roof member capable of being raised and lowered relative to the base. The base is mounted upon a wheel and axle assembly. The roof member is constructed so as to have a storage compartment therewithin for the storage of at least one bed member such as a bed board. Cooperable elements are carried by the bed member or members and by walls of the roof member for guiding the bed members into the storage compartment, for retaining the bed members therein and to facilitate removal of the bed members from the compartment.

Abstract: A sidewall construction for a bus having several fitted sections and seats mounted on the wall. A seat fastening strap is attached to a support tube of the seats and extends downward. One of the sections of the sidewall structure, particularly the bottom arch section at the level of the lower end region of the seat fastening strap, has an angle-shaped recess open at the rim and facing the seat fastening strap. The recess has a hanger bar for hanging the seat fastening strap, and a screw lock for disconnectably fixing the seats in place. The recess has an L-shaped cross-section at the open rim, and two arms connect at right angles to this cross-section. The arms correspond, on one hand, with the seat fastening strap, and, on the other hand, they correspond to a screw bolt passing at right angles through the seat fastening strap.

Abstract: A multi-passenger vehicle such as a bus has a lateral entry and exit door which opens a stairwell. One or more passenger seats are arranged immediately adjacent to the stairwell. The passenger seat is oriented in such a manner relative to the longitudinal axis of the bus that the passenger either faces in the travel direction or in the opposite direction. A foot rest plate covers the stairwell when the door is closed. The foot rest plate is hinged about a horizontal axis extending across the longitudinal axis of the bus. In the upwardly tilted position the foot rest plate does not interfere with the free use of the stairwell for its purpose and in the closed position the foot rest plate makes the particular seat adjacent to the stairwell as comfortable as any other seat in the bus.

Abstract: A glare shield whose body is a sheet of transparent glare reducing material is attached to a vehicle sun visor for use as a downward extension thereof by a clip device having opposed arms engaging the lower portion of the visor from below, one of said arms on its lower outer extremity having a transversely extending partially closed channel for receiving and frictionally engaging a hinge pin attached to said body so as to extend above the central upper marginal edge of said body and parallel thereto by which pin the body is fastened to the clip in hinged relationship and may be rotated from a downward extension of the sun visor to an out-of-the-way position folded back against the visor, and may be used as a vertical downward extension of the visor regardless of its tilt, said arms of the clip being adapted to fit all visors in common use regardless of their thickness.

Abstract: A recliner chair having seat and back portions pivotally connected and supported on a frame structure for movement between an upright position and an inclined position with supporting rollers secured to the seat and rear portions of the frame structure and movable along track means secured thereto.The improved chair includes a modified stop mechanism associated with the rear and front seat supporting rollers and the tracks connected therewith. One stop member includes a bracket mounted on the frame structure which is located in the rear area of the siderail, and serves to stop rearward movement of the rear seat support roller. The bracket includes a retaining member which holds that rear roller therein and accordingly maintains the seat in an upright position. Another stop member is associated with the front support roller and in particular is formed from the rear portion of the track member moving thereon and maintains the seat in its inclined position.

Abstract: In a tunnel boring or shield machine, a method and system for controlling the earth pressure, in which the earth pressure in the chamber of the shield machine body is detected and the detected earth pressure is compared with a reference value to thereby produce a chamber earth pressure deviation signal. In response to the chamber earth pressure deviation signal, means for controlling the amount of conveying earth accumulated in the chamber to the exterior of the machine body and/or means for advancing the shield machine body into the working face are controlled so as to maintain the earth pressure in the chamber within a predetermined range so that the breakdown of the exposed face or earth stratum as well as the rising of the ground are prevented from occurring.In another method and system, the earth pressure at the working face is detected and the detected value is compared with a reference value to produce a signal representing the earth pressure deviation at the working face.

Abstract: A shield type hydraulic tunnel boring machine having means for detecting an occurrence of excess excavation due to accidental collapse in tunnel face ground apt to occur during tunnel boring works through soft and unstable ground and for further determining the location, shape, scale and the like of such excess excavation occurred is provided. The means comprises optimumly a plurality of ultrasonic wave transmitting and receiving devices disposed as spaced at least along a radial line on the front surface of a substantially disk shaped rotary cutter head of the machine for transmitting ultrasonic waves in forward and upward directions and receiving reflected waves from tunnel face ground wall, a wave transmission and reception controlling means, and a transmission-to-reception time interval detecting means for determining distances from the respective wave transmitting and receiving devices to the ground wall.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale. The formation comprises at least one stratum of relatively higher average kerogen content which is included in formation of relatively lower average kerogen content. A void is excavated in a retort site in the formation, leaving a remaining portion of unfragmented formation within the retort site adjacent the void. The portion of unfragmented formation within the retort site is explosively expanded toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ retort in which fragmented formation particles from the stratum of higher kerogen content have a larger void fraction than the averge void fraction of the fragmented mass. This can be accomplished by enlarging the void in the vicinity of the stratum having the higher kerogen content prior to explosive expansion.

Abstract: A low temperature freezing fluid and method are used for year-round wearing away of bitumen deposits, such as those of the Athabaska Tar Sands, by a softening and/or abrasion process. Relatively small size particles of bitumen and its associated foreign matter are produced which enable separation of bitumen at greater speed, efficiency and thoroughness than present methods. Water solutions of calcium chloride having a freezing point down to -46.degree. F. and a specific gravity greater than that of bitumen are used as the fluid. Since bitumen deposits vary considerably in physical properties; optimum softening and/or abrasion efficiency and reduced particle size are achieved by either heating the fluid to 212.degree. F. to soften or refrigerating it to -46.degree. F. to harden the bitumen prior to spraying it at high velocity onto the deposit. At times, faster rates of softening and/or abrasion and reduced particle size are achieved by incorporating abrasion particles in the fluid.

Abstract: The invention concerns a machine for cutting earth formations, of the type comprising a vehicle body, and a power driven rotary cutter mounted on the body. The cutter includes a wheel assembly and a cutter chain mounted in circular fashion around the wheel assembly. The cutter chain comprises a plurality of links connected together by transverse pins, and cutter-receiving sockets carried by the links. The wheel assembly comprises a peripheral surface for supporting the pins, and a plurality of circumferentially spaced recesses in the surface, the quantity and spacing of the recesses corresponding to the quantity and spacing of the transverse pins in the chain such that the pins can be positioned in the recesses. The recesses are of sufficient depth to support the chain in a slackened condition when the pins are positioned in the recesses.

Abstract: An attachment for a cup shaped ornamental hub cap comprises a resilient clip ring assembled with the hub cap. The clip ring comprises an annular dish spring part clamped to the open inner-end of the hub cap to be axially tiltable and a plurality of spring legs extending radially and inwardly from the inner peripheral edge of the dish spring part adapted to engage with an annular recess on a cylindrical flange of a wheel body, whereby in attaching the hub cap onto the cylindrical flange of the wheel body, the spring legs of the clip are resiliently engaged with the annular recess due to tilting movement of the dish spring part.

Abstract: A foil bearing turbomachine including magnetic relief of the thrust forces and static friction imposed on the foil thrust bearing during start up of the turbomachine.

Abstract: A protective control system is provided in a magnetic suspension system having a permanent magnetic and an electro-magnetic circuit for levitating a spinning rotor; normally effective axial stability between limiting positions is provided by a feed back servo system supplying control currents to a pair of solenoids for modulating the permanent magnetic field in the suspension gaps. The physical support system and the suspended apparatus are protected from damage due to excessive axial oscillatory translation of the suspended rotor by detection of such non-linear events and by the removal of the suspension command for a suitable time period. The suspension control is then returned to its initial state and is again set into operation to translate the suspended element asymptotically and smoothly to its desired central location.

Abstract: A mounting assembly for a journal bearing that is adapted to be disposed between a rotating headshaft and a frame member, with the mounting assembly including a bearing cone, resilient compression rings, and outside seal retainer members disposed about the rotating headshaft with the resilient compression rings compressively positioned between the bearing cone and outside seal retainer members to frictionally secure the bearing cone along the rotating headshaft upon axial rotation of the outside seal retainer members with respect to the bearing cone.

Abstract: A gravity closed, spring-biased, door control and hinge configuration located near the center of the top of a display cabinet wherein a spring attached to a lever extending from an L-shaped door is placed under tension when the door is moved to close a combined side-and-top dispensing opening.

Abstract: An electrical connector comprises a tab receptacle having means to latch to a tab mated therewith, the receptacle being contained in an insulating housing having a depressible portion operative to effect release of the latching arrangement acting between the tab receptacle and a tab mated therewith, the depressible portion also serving to retain the tab receptacle in the housing.

Abstract: A measuring electrode, especially a glass electrode, having a body detachably connected by means of a coaxial connection device with a connection cable. The part of the connection device arranged at the body is constructed as a plug portion and its inner plug and coaxially arranged outer plug are separated from one another by means of an insulating body. The outer plug is axially rearwardly set back in relation to the end of the insulating body of the plug portion. An insulating body of a bushing portion of the connection device engages in a cap-like manner over the free part of the insulating body of the plug portion.

Abstract: A strain relief arrangement associated with a removable wall of a housing includes an integral member which defines a cavity; a post within the cavity; and a slot communicating with the cavity and the inside of the housing. The wall and member provide a depressed region adjacent the cavity, the depressed region including a set for a removable cover, and a pair of holes through which fingers of the cover can engage the inside of the wall. When the fingers engage the wall, a screw can be put through a hole in the cover to engage the post and secure the cover. An abutment on the cover cooperates with the cavity to define a second slot, each of the slots being large enough to slidably but snuggly accommodate a power cord. A cord extending through the slots and around the post is anchored by the assembled arrangement.

Abstract: Surgical microscope in which the microscope body is mounted on a support member which is laterally and vertically swingable and slidable along its longitudinal axis. The body comprises an objective lens tube mounted on said support member and having a pair of objective lenses. The objective lens tube can be mounted on said support member at two different positions for accommodating two different types of binocular tubes.

Abstract: An improved connector is disclosed for interconnecting a plurality of fiber optic cables with a like plurality of fiber optic cables or optical devices, the fibers of the cables being accurately positioned within the respective connectors. The subject connector can be used for either splicing or terminating individual cables, each cable including at least one fiber, as well as connecting a plurality of light transmitting fiber bundles in a single connector assembly to transmitting and receiving devices. The subject connector includes a housing with at least one cable receiving bore therein; an assembly including an annular crimping ring, a profiled ferrule member, and a helical spring member secured to an end of each cable; and a cap member securing the ferrule members in the housing member in a spring loaded condition.

Abstract: An oversized connector providing an optical fiber bonded in a bore hole is machined about the center axis of the optical fiber to properly center the optical fiber in relation to the centerline of a receptacle for the connector containing another optical fiber whose central axis is also in line with the centerline of the receptacle.

Abstract: An optical transmission fiber having improved mechanical strength and suitable for use in optical communication comprising an optical fiber having formed thereover at least one layer of a composition mainly comprising a thermoplastic resin having a functional group, and a method for making the optical transmission fiber.

Abstract: A remotely adjustable mirror assembly in which a reflective member is supported on a tilting mechanism which includes a pair of selectively movable ramped cams. The cams are coupled to gripper devices to grip or release a member which is reciprocated by a pair of alternately energized solenoids. The gripper devices are also solenoid operated and include either a recessed head or a double-gag plate head to grip or release the reciprocating member. A multiposition, joy-stick operated switch provides eight operating modes for selectively adjusting the position of the member in azimuth, or elevation, or both. A pulse generator producing two trains of oppositely phased pulses is connected through the multiposition switch to the solenoids for the reciprocating member. Two types of switch are described.

Abstract: A liquid crystal display device characterized by a liquid crystal cell having a layer of liquid crystal material, which is switchable on a zonal basis between various optical states, interposed between a front and rear carrier plates; a fluorescent plate which is disposed behind the rear carrier plate of a liquid crystal cell in the path of observation and has light emergent or exit windows disposed behind the switchable liquid crystal zones; and at least one supplemental light source in optical contact with the fluorescent plate to provide light for exciting fluorescent centers in the fluorescent plate. The fluorescent plate has silvered edge surfaces and consists of a material which has an index of refraction greater than 1 and contains the fluorescent centers which are excited by ambient light to emit a fluorescent light isotropically. Preferably, the liquid crystal layer is interposed between front and rear electrodes which control the optical properties of the layer.

Abstract: An electrochromic display device has an improved counter electrode arrangement. The device has a plurality of display elctrodes and a counter electrode in contact with a first electrolyte of a primary redox system. The counter electrode is charged to a predetermined potential. A secondary redox system is associated with the primary redox system. A secondary electrode in the secondary redox system is electrically connected to the counter electrode to maintain the charge on the counter electrode at a predetermined potential.

Abstract: An electrochromic display device adapted to be accurately erased has an opaque counter electrode in the shape of a pattern of lines, preferably reticulate, on the underside of the face of the display device through which the display is viewed. The counter electrode is brought to a predetermined potential either by trapping a suitable material capable of a reversible redox reaction at the counter electrode or by initially charging the counter electrode with heptyl vilogen cation radical. This enables voltage erase to be used.

Abstract: A lamp assembly and power module is provided for a microform display apparatus, such as a fanless microfiche reader. The lamp assembly and power module are both situated in a drawer which is removably inserted into the base of the reader to form an air-restricted path for the efficient convection of heat away from the reader. By setting the lamp at an angle to the longitudinal axis of the drawer, both the lamp assembly and power module components can fit in the drawer. The front end of the drawer is provided with a grille for air passage, and a chimney structure is situated adjacent the rear of the drawer for the efficient evacuation of heat. The lamp and power module are located below the chimney, and as the lamp and power module components heat the surrounding air, the air rises up the chimney and out of the reader by convection. This air movement creates a draft through the grille in the front of the drawer, which serves to sufficiently cool the components.

Abstract: A projector casts light rays upon a reflective surface to produce a focused scene, and within the periphery of the scene the reflective surface has a small aperture. Behind the aperture is a concave mirror which is positioned to intercept the projected rays that pass through the aperture. The mirror reflects these rays onto a small screen which is located adjacent to the aperture. The arrangement is such that the reflected rays come into focus at the small screen, producing a focused image of that portion of the scene seemingly lost at aperture. Light from this image is in turn reflected by the mirror so as to create a real image, the location of which is the aperture in the reflective surface. Thus, the real image of the small screen is observed at the void left in the reflective surface by the aperture and blends in with the remainder of the scene on that surface. As a result, the aperture is practically indiscernible.

Abstract: A camera exposure control circuit performs exposure control and a series of photographic functions digitally by means of digital operation process circuits and a sequence control circuit. In the sequence control circuit a random logic circuit is used to control the camera in an efficient way and to minimize the number of the components of the camera itself.

Abstract: A focal plane shutter camera of a type which employs photometry measuring light reflected by the shutter blind and/or the film has an electromagnetic diaphragm mechanism and is capable of automatic photographing with a preset exposure. By providing at least two light receiving elements which perform the photometry of reflected light to automatically determine an exposure value, the camera may select among four photographing modes including a manual photographing, an automatic photographing with a preset diaphragm aperture, an automatic photographing with a preset exposure period and an automatic programmed photographing operation.

Abstract: In a motor drive unit for a camera, a body is provided with a camera attaching surface, a portion of which holds a dust shielding cover which receives a winding member of the camera. A set screw is adapted to mount the body onto the camera. A control drives a wind-up motor after each exposure of the camera.

Abstract: Dating information is applied to camera film from date information displaying circuitry which receives decoded electronic time signals generated by a chronometer. A first power source energizes the chronometer and a second power source energizes the decoder and display circuitry and other components such as the exposure control circuit. A monitor is provided to enable the camera operator to observe the date information. Manually operable switches are provided to independently actuate the dating apparatus and the exposure control circuit as well as to independently operate the display circuitry and the monitor.In a modified embodiment, logic and switching circuitry are provided to monitor and date either exposure data obtained from a light measuring circuit and analog/digital converter or the date information generated by the chronometer. A manually independently operable switch for actuating the display circuitry is ganged with the switching circuit to expose the date information on the film.

Abstract: An automatic focusing apparatus for a camera comprises a camera to photographic subject ranging device for providing a signal indication of elapsed time corresponding to the camera-to-subject distance and an objective lens arrangement displaceable between a plurality of focal positions at a rate such that the objective lens arrangement reaches each of its plurality of focal positions at an elapsed time from its initial displacement directly proportionate to the elapsed time indicated by the ranging device.

Abstract: A shutter release mechanism is provided in a camera, which includes an electromagnetic circuit, in which an electric power source, an electromagnet for operating a shutter, and an actuating switch are operatively interconnected. Provided in the camera shutter release button is a coupling section, to which are selectively attachable the tip portion of a mechanical cable release and the tip portion of an electric remote control release having therein a manual operating switch. When the shutter release button is operated, or when the tip portion of the cable release is attached thereto and depressed, then a movable member provided internally of the camera is advanced so as to close the switch provided in the body of the camera, thereby mechanically operating the electro-magnetic release means.

Abstract: A photographic film assemblage of the self-developing type is specially configured for use in conventional cameras including those of the 35mm type. Photographic processing apparatus is provided for use in conjunction with the self-developing type film assemblages which have been previously exposed by the conventional type camera. The film assemblages comprise a substantially lighttight cartridge into which the film strip may be rewound subsequent to exposure in the conventional type camera thereby facilitating its removal from the camera and its insertion into the processing apparatus which operates again to withdraw the film strip from its cartridge so as to effect the processing of the film strip. After processing, the film strip is advanced from the processing apparatus to provide a plurality of fully developed transparencies which may be cut and framed in a conventional manner.

Abstract: In a diazo-type copying apparatus, an improvement to prevent external leakage of gaseous ammonia to the atmosphere. The apparatus comprises a developing chamber, transport means within the chamber, means for introducing ammonia gas to the chamber, a first enclosure enclosing the chamber for sealing it from the atmosphere, a second enclosure containing the first enclosure as well as a perforated vacuum tube for collecting ammonia gases escaping from the first enclosure as well as for scrubbing ammonia gases from developed copies and exhausting the gases either to a liquid ammonia absorbing solution, a filter containing an ammonia absorbing solution, a cartridge containing ammonia absorbing pellets or a catalytic converter thereby preventing the ammonia gases from contaminating the atmosphere.

Abstract: A processing apparatus has a processing chamber configured to receive a plurality of cylindrically-shaped film units. The film units comprise a plurality of film discs supported by a central aperture on an elongated shaft, in spaced relation and with the disc faces normal to the shaft axis, and end drive discs slightly larger in diameter than the film discs. The drive discs have a guide lug extending from their exposed sides and guide grooves are provided in the processing chamber interior. The first inserted film unit is directed into driving engagement with a drive means located at the lower portion of the chamber and subsequently inserted film units are directed into driving relation with the unit therebeneath. Processing fluids are sequentially introduced and discharged from the chamber with the film units rotating to effect film development.

Abstract: A photosensitive drum for electrographic apparatus composed of a drum-shaped photosensitive body and producing thereon an electrostatic latent image corresponding to a picture image of a manuscript to be reproduced. The apparatus comprises a mechanism for frictionally braking the rotation of the photosensitive drum.

Abstract: A plurality of electrostatic copying machines (12), (13), (14), (16) are interconnected by bus lines (19), (21), (22). Each copying machine (12), (13), (14), (16) is provided with a sensor unit (23) for sensing various status parameters of the copying machine (12), (13), (14), (16) such as whether the copying machine (12), (13), (14), (16) is available for use, the copy sheet size, the number of copies made, the number of copy sheets remaining, etc. Each copying machine (12), (13), (14), (16) is further provided with a display unit (17) for displaying the status parameters of all of the copying machines (12), (13), (14), (16). A microcomputer (31) is provided at one of the copying machines (12) for storing and processing the status parameters and producing a hard copy.

Abstract: Reproduction apparatus for producing simplex or duplex copies. A plurality of individual reusable photoconductive members are provided in a supply and are sequentially transported around a path back to the supply. Positioned along the path are charge, expose, development, transfer and cleaning stations. In the simplex mode, first toner images are sequentially formed on photoconductive members transported around the path and sequentially transferred at the transfer station to first sides of copy sheets brought into transferable relationship with the photoconductive members. In the duplex mode, first and second toner images are formed on first and second photoconductive members respectively transported around the path and the toner images are transferred at the transfer station to opposite sides of a copy sheet brought into transferable relationship with the first and second photoconductive members.

Abstract: In an apparatus for xerographically printing a composite record based on first and second complementary sources of information. The first source of information is imaged onto a photoconductive drum to form a first electrostatic image thereof. The second source of information may be derived from a central processing unit in signal form. The signals received from the CPU are used to modulate the output beam of a scanning laser. The modulated laser output beam is directed to a stylus belt positioned in close surface proximity to the photoconductive drum bearing the first electrostatic image. The stylus belt includes an electrcially conductive layer and a photoconductive layer, and is responsive to the incident laser energy to translate it into a corresponding charge pattern. This charge pattern is overlaid on the first electrostatic image to form a composite electrostatic image. The composite image is then developed and transferred onto a record medium in a conventional manner.

Abstract: An improved electrographic recording system. The system includes a first charging corona for providing a distribution of charge on a surface of a recording medium representing a desired image to be recorded on the medium. The system also includes an automatically controlled second charging corona. A sensor continuously monitors the potential of a conductive layer of the medium and automatically controls the magnitude of the charge deposited by the second charging corona so as to maintain a constant potential at the conductive layer of the medium.

Abstract: A method and apparatus is described by which photocopies can be obtained from documents and the like without the need for optical means for forming focused images of the documents.