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: 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 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. The metering roll has a central metering portion and a distance control position at each end. The metering portion and the distance control portions are coaxial and have a fixed angular relationship with respect to each other. The metering roll distance control portions are urged against the moving copier photosensitive drum surface and rotate in the same angular direction as the drum. Thus the distance control portions engage drum surface edges in a sliding frictional relationship. The distance control portions are sized to maintain the central metering portion in a substantially constant spaced apart relationship to the drum surface and thereby tend to limit and control the thickness of developer on the drum surface at the transfer station.

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.

Abstract: A system for developing a latent electrostatic image pattern formed on a coated photoconductive paper and which utilizes a nonconductive transfer cylinder that encloses a rotating cylindrical magnet. The magnet produces a longitudinally uniform magnetic field at the outer surface of the cylinder that draws a polarized, magnetically attractable, one component toner material over the outer surface of the transfer cylinder from a toner supply means to a deposit zone over the paper. A roller, plate, or other suitable unit under the paper supports the paper with a uniform, preselected minimum spacing between the transfer cylinder and the electrostatic image pattern on the paper. In the deposit zone electrostatic forces and gravitational forces urging the toner material from the transfer cylinder to the paper exceed the magnetic forces holding the toner on the transfer cylinder causing the toner to deposit selectively in the image areas.