Abstract: A jam detector circuit for use in a photocopier employs feedback and visual indication circuitry for providing a stable and easily adjusted detector. Feedback is provided to desensitize the circuit to sensing device operating parameters which vary according to and within manufacturing specifications. The visual indication circuitry allows a predetermined range of signal change to be defined thereby enabling easy "set-up" of the circuit without the need of electrical metering apparatus.

Abstract: A sheet stripping apparatus and method used in a photocopying machine employ a resiliently biased sheet stripping element in contact with the photosensitive surface of the copier for detaching a leading edge of a copy sheet as it moves toward the sheet stripping assembly. A moving deflection surface, such as a knurled roller, is positioned immediately adjacent the operative portion of the sheet stripping element for deflecting the detached leading edge of the copy sheet away from the sheet stripping element and toward an exit path. A friction roller in juxtaposition to the deflection surface provides a nip for grabbing the copy sheet and directing it along the exit path. The friction roller is preferably driven at a velocity greater than the velocity of the photosensitive surface.

Abstract: In a photocopier, a sheet hold down member with a rounded end, extends to the photosensitive drum surface from a resilient support, adjacent the edge of a pick-off blade, near where sheets conveyed to the drum surface transfer station arrive. Portions of the sheet adjacent the blade are held down by the member to contact the image bearing drum surface, thereby minimizing image lost to the sheet.

Abstract: A method and apparatus are described for correcting a jam condition in a photocopier, the copier having a transfer station at which a developed image is transferred from a moving photosensitive surface onto a sheet material and a cleaning station having a cleaning blade bearing against the width of the photosensitive surface. The apparatus has energy transmitting and receiving elements which detect the presence of unremoved sheet material on the photosensitive surface between the transfer station and the cleaning station and provides for continued movement of the photosensitive surface until the sheet material strikes the cleaning blade. In this way, a buckle is formed in the sheet material between the cleaning station and the transfer station which facilitates removal of the sheet from the copier.

Abstract: In an optical imaging system for an electrophotographic copier, a photodetector intercepts a portion of unfocused light being reflected toward the photoconductive surface. An electronic circuit generates a biasing voltage for the copier development electrode which varies with the amount of light incident on the photodetector a set time after the photodetector receives a distinctively intense light pulse reflected from a high-reflectivity strip positioned ahead of the document being copied. The time delay insures that the light which determines the bias voltage has been reflected from the main body of the document. The light pulse from the high reflectivity strip can also independently actuate the copy paper feed mechanism to insure proper image registration.

Abstract: A sheet stripping assembly has a sheet removal blade moveable between a first position overlying a marginal portion of a photosensitive member of a copying apparatus and a second position in which it does not overlay the photosensitive surface marginal portion. Trip elements mounted on a moving platen control movement of the blade through a blade moving mechanism. At the end of a copy cycle, the blade is left in the second position.

Abstract: A curved blade overlays the marginal portion of a photocopier drum photosensitive surface at the transfer station to engage copy sheets and direct them to a transport assembly removing the sheets from the transfer station. The blade is pivotally mounted at one end and connected to a reciprocating actuator at the other end. It is pivoted away from its overlaying position, after the transport assembly engages the leading corner of the sheet so that the sheet can then contact the marginal portion, and back to its overlaying position after the trailing edge of the sheet has left the surface of the drum. In one embodiment the actuator is mechanically responsive to the photocopier scanner. In another embodiment, the blade is pivotable about an intermediate portion, and the actuator is operated by a solenoid energizable by a switch at the appropriate times.

Abstract: An apparatus for cleaning residual toner from the photosensitive surface of the rotating drums of photocopying machines. The cleaning assembly includes at least a cleaning roller and a cleaning blade which are moveable from an inoperative position spaced away from the photosensitive surface to an operative position in contact with the surface. In operation, the rotating drum begins its rotation while the roller and blade are in their inoperative position. The drum surface contacts liquid developer solution at the developing station. The roller and blade contact the drum after a predetermined time duration and therefore contact a wetted drum surface so as to avoid possible damage to the photosensitive surface and the cleaning members. A delay arrangement directs developer to the cleaning blade and roller when they are in their operative position contacting the drum.

Abstract: A tray with a ramp plate is insertable into a tray receiving assembly of a photocopier. The assembly includes an opening up through which a lift member is moveable for engaging the bottom of the ramp plate through an opening in the tray bottom when the tray is inserted. A locking bracket is pivotable to a position extending through the assembly opening to engage the bottom of the tray. A locking handle is linked to a shaft carrying the lift roller to hold the lift member in a disengaged position in which it keeps the locking bracket in a disengaged position. The base of the tray includes an elongate projection with a protruding upper surface about which the rear edge of the ramp plate is pivotable.

Abstract: Disclosed are blades oriented in a trailing configuration for cleaning residual toner from the photosensitive drums of photocopying machines without marring the drum's surface. In one embodiment of the invention, the blade is constructed of layers of resilient material having different moduli of elasticity resulting in the blade's having greater resistance to transverse deformation than to deformation along the primary axis of the blade. In another embodiment, the blade comprises a mass of an elastic material having a partially hollow interior. The hollow interior results in a blade with differing moduli of elasticity in different directions.

Abstract: A support structure located in the interior of an electrophotographic copier photoconductive drum to guide removal of the drum from its rotational shaft while eliminating potentially injurious radial movement, has extender guides which can protrude from the end of the drum to provide an effective continuation of the guiding surface provided by the support structure. Each guide, upon which the inner surface of the drum will ride during removal, can, during normal operation of the copier, be held in an inoperative position within the drum interior. The outwardly protruding ends of the guides also can be beveled or tapered to facilitate reinstallation of the drum into its operating position within the copier.

Abstract: Disclosed is an accurately adjustable mount for supporting a corona assembly of a photocopying machine. The accurate adjustment of the separation between the corona wires and the photosensitive surface of the photocopying machine is accomplished by separate cam mechanisms located at either end of the corona assembly. Locking means are provided for securing the corona assembly after the proper separation has been established by the cam mechanisms.

Abstract: A metering roll, employed between the developing station and the transfer station of a photocopier which uses a liquid toner, controls the thickness of the liquid on the photosensitive drum surface when it is presented to the transfer station. Elements fixed between the drum and roll maintain the central metering portion in a substantially constant spaced apart relationship to the photosensitive drum surface and thereby tend to limit and control the thickness of developer on the drum surface at the transfer station. The elements have different surfaces in sliding, frictional contact with the drum and roll respectively. In one embodiment the elements are strips with opposite parallel surfaces, one in contact with the drum and the other in contact with the roll. In another, the ends of the strip are mounted on reels so that the strip may be moved to vary wear points on the strip if any appear.

Abstract: A metering roll, employed between the developing station and the transfer station of a photocopier which uses a liquid toner, controls the thickness of the liquid on the photosensitive drum surface when it is presented to the transfer station. Shoe-like elements fixed between the drum and roll maintain the central metering portion in a substantially constant spaced apart relationship to the photosensitive drum surface and thereby tend to limit and control the thickness of developer on the drum surface at the transfer station. One surface of the element substantially conforms to an arc of the drum surface and another surface defines a hole through which a portion of the metering roll passes.