Abstract: My invention comprises an improved method of electrophotography which enables me to increase the effective speed of a photoconductor. The distinguishing feature of xerography is the creation of an electrostatic image at some point in the process. Most conveniently, a photoconductor is charged in the dark and then exposed to a light and shade image of the original to produce a latent electrostatic image of the original. In order to make a satisfactory copy, the exposure time must be such that sufficient contrast is achieved to enable the latent image to be made visible by the application of a developer formed of inherently colored or pigmented minute charged particles. The speed at which copies may be made is the function of the quantum of light falling on the photoconductive surface and the conductivity of the photoconductor under illumination.

Abstract: A pickoff element for separating a carrier sheet from the photoconductor drum of a liquid-developer electrophotographic copier following transfer of a developed toner image to the sheet is incrementally moved transversely of the direction of movement of the photoconductor to distribute wear over a relatively large portion of the photoconductor surface. Upon its return to home position, a copier scanner casting strikes an actuator arm coupled through a one-way clutch to a double-helix lead screw, extending parallel to the drum axis, to impart incremental unidirectional rotation to the lead screw. A follower engaging the lead screw is coupled to the pickoff element to shift the pickoff element transversely in response to the rotation of the lead screw.

Abstract: An automatic biasing mechanism for a paper cassette support plate for use in an electrophotographic copier in which a removable paper cassette is provided with a plate upon which a supply of copy sheets is placed. A feed roller assembly within the copier is adapted to remove the uppermost sheets of paper from the cassette and activate a sensor when the top of the stack of sheets falls below a predetermined level. The sensor provides an output energizing a motor to rotate a shaft having a roller adapted to pivot the plate to move the stack of sheets to a position at which the uppermost sheet engages the feed roller assembly. The shaft, normally biased so as not to be in driven engagement with the motor, is moved into operative relationship with the motor by the cassette upon its insertion in the copier.

Abstract: A blade for cleaning toner from a liquid developed imaging surface comprises a body of high conductivity formed of rubber impregnated with carbon particles and a tip contacting the imaging surface formed of an inherently conductive rubber of lesser conductivity, the liquid developer affecting the conductivity of the body but not that of the tip, and the tip being replaceably inserted in a cooperating re-entrant cavity of large surface area formed in the body to provide a low contact resistance therebetween.

Abstract: Apparatus for feeding balls one by one from a cylindrical reservoir in which a rotary saw blade disposed at the bottom of the reservoir is driven to move balls resiliently fed to the intertooth recesses of the blade into the entrance of a passage out of which the balls are fed. Balls are biased into the intertooth blade recesses for reliable high-speed operation by a helical coil spring disposed over the blade in one embodiment or by a plurality of permanent magnets fixedly disposed below the blade recesses in another embodiment.

Abstract: Apparatus for separating sets of sheets such as copy sheets from an electrophotographic copier by delivering alternate sets of sheets to a stationary tray along overlapping laterally spaced paths. Sheets are fed first through a first, transversely fixed assembly of opposing feed rollers and then through a second, transversely movable assembly of feed rollers into a stacking tray. Sheets belonging to alternate sets are offset by shifting the second set of rollers laterally following the emergence of their trailing edges from the first set of rollers. In the preferred embodiment, the emergence of the trailing sheet edge from the first set of rollers is sensed by driving the second set of rollers at a slightly greater linear speed and sensing the retarding torque transmitted through the sheet from the first set of rollers.

Abstract: A stationary light source electrophotographic copier wherein collimated light from the source is directed to a scanner having upper and lower document illuminating reflectors comprising thin members of negligible mass maintained under tension. The lower reflector includes a plurality of generally horizontal slats disposed in a generally vertical array. Heat from the stationary light source is used to dry or fix copies.

Abstract: A low profile keyboard actuator for a typewriter in which L-shaped levers are pivotally mounted on a transverse shaft mounted immediately in front of the typewriter. The levers have generally horizontal arms of various lengths, the ends of which contact the keys of the various rows of the keyboard. The levers have depending arms of uniform length and are resiliently biased to depress the keys. A common operating bar bearing against the depending arms cyclically permits the levers to depress the keys and then restores the levers to the original position where no key is depressed; however, depression of all but a selected key is inhibited by a plurality of vertically superposed, transversely shiftable, binary-coded slides having teeth which bear against all depending arms except that one corresponding to the selected key.

Abstract: This invention relates to a composition for developing latent electrostatic images by liquid development and a method of transferring the developed image to a carrier sheet over a gap. The gap is formed by dielectric spacing particles disseminated through a dielectric carrier liquid, through which toner particles are also disseminated. The toner particles and the spacing particles bear the same surface charge so as to repel each other while in the developing liquid. Apparatus is provided, for use of the novel developing composition, which includes a metering means adapted to remove excess liquid from the surface of a developed image. In order to induce the spacing particles to migrate toward the photoconductor, the metering means is biased to a potential greater than that of the non-image areas. This enables the spacing particles, which have a higher dielectric constant than the carrier liquid, to migrate toward the photoconductor.

Abstract: A centrifugal ball elevator for use in a microballistic impact printer or the like in which a hollow rotary member arranged on a generally vertical axis and having an inlet at the lower end and an outlet at the upper end is formed with an internal surface extending between the inlet and the outlet with a radius that increases from the inlet to the outlet. Balls to be elevated for recycling through the printer are supplied to the lower end of the surface through the inlet, while the member is rotated at such a speed as to impel the balls toward the outlet under the action of centrifugal force. In certain disclosed embodiments the internal surface is so formed as to entrap or filter out contaminants which have accumulated on the balls, while in another disclosed embodiment the internal surface is provided with a self-lubricating coating which lubricates the balls to reduce the abrasive effect of the balls on constricted portions of the printer through which they pass.

Abstract: This invention relates to a composition for developing latent electrostatic images by liquid development and a method of transferring the developed image to a carrier sheet over a gap. The gap is formed by dielectric spacing particles disseminated through a dielectric carrier liquid, through which toner particles are also disseminated. The toner particles and the spacing particles bear the same surface charge so as to repel each other while in the developing liquid. Apparatus is provided, for use of the novel developing composition, which includes a metering means adapted to remove excess liquid from the surface of a developed image. In order to induce the spacing particles to migrate toward the photoconductor, the metering means is biased to a potential greater than that of the non-image areas. This enables the spacing particles, which have a higher dielectric constant than the carrier liquid, to migrate toward the photoconductor.

Abstract: At the cleaning station of a photocopier, a cleaning system including a wetted cleaning roller of resilient closed-cell material and a sealing roller of resilient noncellular material past which cleaning and sealing rollers the imaging surface is sequentially moved. The cleaning roller contacts the imaging surface and is so driven that its surface adjacent to the imaging surface moves in a direction opposite thereto to provide a scrubbing action. The sealing roller contacts the imaging surface and is so driven that its surface adjacent to the imaging surface moves in the same direction as and at the same speed as the imaging surface to provide a dynamic seal. Preferably, the sealing roller has a surface smoothness of between 2 and 10 microinches. The sealing roller may be formed by casting polyurethane in a glass tube to form an extremely smooth outer surface which provides a highly effective seal with the imaging surface against the flow of cleaning liquid.

Abstract: A copier in which a processing unit carrying a photoconductor drum, an exposure system, a liquid developer applicator, an excess liquid removal member, and a cleaning member is mounted for reciprocating movement with a forward stroke and a return stroke below a platen supporting the original document and in which a drive translates the unit while rotating the drum in synchronism with the translatory movement of the unit. A paper handling unit carrying a pair of registration rolls, a transfer corona, a copy paper pick-off, and a pair of delivery rolls, is mounted for reciprocating movement between a registration position at which its registration rolls receive a sheet from a supply of copy material and a position adjacent to the delivery end of the machine. In operation, the processing unit moves from its home position toward the registration position as the initial part of the image of the original is formed and developed.

Abstract: A pulse width modulation system for encoding and decoding digital information in which the encoded signal comprises a series of transitions among different signal levels wherein the length of time between transitions determines the value of a digit, so that each digit is represented by one and only one transition.

Abstract: An improved hold-down arrangement for a copy sheet pickoff system in which a pressure finger of insulating material is mounted on the removable transfer corona assembly in such a way that when the assembly is placed in operative position on the machine the pressure finger is located adjacent to the forward edge of the pickoff blade with the operative end of the finger spaced out of contact with the drum by a distance which is approximately equal to the thickness of a sheet of copy paper.

Abstract: A document feeder for advancing original documents to the exposure platen of an electrophotographic copier which is capable of operating in either a semiautomatic or fully automatic mode. In the semiautomatic mode, an original to be copied is manually inserted face up into an inlet where it is engaged by the semiautomatic transport assembly inverted and advances to a proper position for copying. After exposure the document is again inverted and guided into a receiving tray overlying the platen. In the automatic mode of operation, a second tray normally maintained in an inoperative position is swung down to a position at which its feed end is adjacent the feeder inlet. Documents to be copied are placed face up as a stack in the second tray, and feed rollers carried by the tray are actuated to advance documents individually from the stack to the inlet.

Abstract: Electrophotographic copying apparatus for use with a composition containing spacing particles to provide a gap between the developed image on the photoconductor and the carrier sheet to which the image is transferred, in which a reverse roller reduces the excess liquid on the developed image before transfer, which reverse roller is a metering device biased to a potential greater than the non-image areas of the developed image. The bias on the metering device impresses a potential of opposite polarity to the polarity of the toner particles to hold the toner particles forming the developed image on the photoconductor.

Abstract: My invention comprises a large capacity combined magazine and sheet feeder for copying machines, in which the sheet being fed is brought to feeding level by a spring-powered mechanical servomechanism. The assembly is adapted to be substituted for a small capacity cassette on an existing copy machine and to employ the power and logic of the existing machine to feed sheets from the large capacity assembly in proper synchronzied relationship. This is accomplished by a power take-off from the copy machine with which the improved magazine is beng used, which power take-off can be installed without altering the original machine. The large capacity unit then feeds sheets to the copy machine as if the original small capacity cassette were being used. The magazine is adapted to handle sheets of various lengths on which copies are to be made.