Abstract:
Documents are advanced to a registered position along the trailing edge of the exposure platen of an electrophotographic copier by a flat belt supported adjacent to the registration edge by a pulley formed with axially spaced indentations to produce corresponding corrugations in the belt. A registration gate having a blocking position in which transversely spaced fingers extend into the belt corrugations arrests the documents at the registration edge while the normal-diameter portions of the belt pulley press the document downwardly to prevent it from riding over the registration gate. Position pulses from an encoding wheel are counted to determine the position of the document, and drive motor is slowed to one-fifth its normal speed when the document advances within a predetermined distance of the registration edge. After the platen belt is stopped for copying of a first original, a second original is advanced from a stack into a nip formed by the belt and a preregistration roller adjacent the entrance end of the platen. Upon actuation of the belt to feed the preregistered sheet to the platen, the feed elements for advancing the sheets from the stack are momentarily reactuated to ensure separation of the sheet supplied to the preregistration nip from the remaining sheets in the stack. A relatively long prefeed time is alllowed for advancing the first original to the preregistration nip to prevent the erroneous declaration of a fault while an initially loaded stack is becoming entrained in the stack feeding elements.
Abstract:
An optical scanning system for a variable-magnification electrophotographic copier includes a first scanning carriage reciprocated along a path by endless bands attached to the carriage at transversely spaced locations and driven purely by friction. Pulleys mounted on a second scanning carriage at transversely spaced locations roll between the drive bands and stationary guides to move the second carriage at half the speed of the first carriage. The second carriage may be shifted relative to the first carriage by moving it to a location at which arms lift the pulleys from the guides. A flywheel rotating at the desired scanning speed is coupled to the scanner drive train after the drive train has been smoothly accelerated to the desired scanning speed, and is uncoupled from the scanner drive train before the drive train is decelerated at the end of the scanning stroke. Misalignments between the separately driven ends of the first carriage are corrected by intercepting the carriage ends to induce differential slippage in the portions of the drive train coupled to the respective carriage ends. Similar misalignments between the separately driven ends of the second carriage are corrected by commonly rotating gears at the respective carriage ends that mesh with fixed teeth at one end of the scanning path. Misalignments between the first and second carriages are corrected by a gear, carried by one of the pulleys of the second carriage, which meshes with a normally immobilized gear as the second carriage moves past the same location.
Abstract:
Apparatus for repositioning the lens of a variable-magnification electrophotographic copier to change the image-side path length for a different magnification ratio and for concomitantly adjusting the shutter to compensate for the changed image-side path length. Actuation of a stepper motor rotates a pulley to tension a cable coupled to the lens, pulling the lens to the desired position of a linear track. A portion of the cable extends around a pulley having an axially projecting circumferentially extending ramp on one face. A follower engaging the ramp is coupled to slit-forming members adjacent to the photoconductor so that movement of the cable to reposition the lens produces a concomitant adjustment of the width of the slit to equalize exposure of the photoconductor over a substantially continous range of selected magnifications.
Abstract:
An electrophotographic copier for selectively printing in one of a number of different colors in which development takes place at a common station around the periphery of a photoconductive drum to which station a distributor system selectively feeds liquid from one of a number of supply containers and from which the liquid is returned to the container from when it came. Our machine flushes the common portion of the liquid circulating system each time a change in color is made. The processing liquid tanks of our machine are provided with an arrangement for inhibiting settling of toner particles in the tanks.
Abstract:
An electrophotographic copier in which a manually releasable locking mechanism normally locates the machine drum in an operative position in the machine cabinet in which peripheral edge portions of the drum engage a pair of friction rollers positioned adjacent to the image receiving portion of the drum. Upon release of the locking mechanism and without the use of tools the drum automatically moves to a location at which at least a part thereof is clear of the machine housing at an access opening thereof.
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. As it moves through the registration location, the processing unit picks up the paper handling unit and automatically provides a drive for the rollers thereof as the two units move together toward the delivery end of the machine. As the leading edge of the copy reaches its terminal location in the tray, movement of the units reverses and the copy delivery operation is completed during this reverse movement, before the paper handling unit returns to the registration position.
Abstract:
A novel liquid composition for developing latent electrostatic images whereby to form a gap between the developed image and the carrier sheet to which the developed image is to be transferred. The composition is such that it contains both charged and uncharged spacer particles. The spacer particles are of larger diameter than the toner particles so as to form a gap between the developed image and the carrier sheet to which they are transferred. The spacer particles, furthermore, have a specific gravity lower than the specific gravity of the carrier liquid, which may be a low-boiling hydrocarbon. This is accomplished by having a gas bubble enclosed in a portion of the material of which the spacer particles are formed, which material is preferably glass. The charged spacer particles may be coated with a polymer of which the toner particles are formed. Both the coated spacer particles and the toner particles bear the same charge. The remainder of the spacer particles are substantially uncharged. The uncharged spacer particles will remain on the background areas of the developed image and prevent the carrier sheet from absorbing liquid present in the developing composition. The charged spacer particles will go to the image areas and become agglomerated with the toner.
Abstract:
A facsimile scanner in which each successive line of an original is scanned by firing a light-reflective or light-refractive spherical projectile along a path over which an optical image of that line is formed to produce a time-varying pattern of reflected or refracted light from the projectile as it traverses the path. A photodetector responsive to light diverted from the projectile provides the facsimile signal. In the recording mode, each successive line of a facsimile signal is recorded by illuminating the same projectile with light modulated by the facsimile signal as the projectile traverses its path to produce a spatially varying pattern of reflected or refracted light, an optical image of which is formed on a recording medium such as the photoconductor of an electrophotographic copier. The rate at which the photodetector output is sampled in the scanning mode and at which the facsimile signal is fed to the modulator in the recording mode is adjusted for the actual measured velocity of each successively fired projectile.
Abstract:
Photocopier scanning apparatus wherein a scanning carriage is mechanically driven by a pair of flexible cables acting on the carriage at widely spaced points on either side of its center of gravity. The cables may be electrically conductive to energize an illuminating lamp mounted on the carriage. The carriage rests on glass slides having arcuate surface portions and is further urged thereagainst by forces from permanent magnets. The carriage is resiliently biased to return to an initial position. The velocity with which the carriage returns is limited; and the return velocity is further damped adjacent the initial position.
Abstract:
In an electrostatic copier having an applicator electrode positioned closely adjacent but not touching the photoconductive surface on which there is a latent electrostatic image to be developed. The surface of the latent image and the surface of the applicator electrode move at the same speed, or the electrode may move at a greater speed. The electrode and the photoconductor are spaced from each other by a gap in the order of between three and six mils. The applicator roller is mounted with its lower segment immersed in a tank containing a developing liquid bearing charged toner particles. There is a mechanism for increasing the liquid to the gap, such as a drive for speeding the rotary electrode to more than the photoconductor speed. After the latent image has been developed, a metering roller, which is a roller whose surface moves in the direction opposite to the surface of the photoconductor, meters or dynamically removes a portion of the liquid from the developed image. The freshly developed image is then transferred to a carrier sheet. An arcuate field electrode is positioned between the metering station and the transferring station. The field electrode is biased to a potential of a sign opposite to the charge of the toner particles.