Abstract: Disk storage apparatus includes a loading and unloading mechanism for moving a recording disk from an insertion position to a reproduction position within the apparatus. When the disk is in the reproduction position, a locking mechanism is moved out of contact with an actuator which carries a read/write head so that the head can be moved across the surface of the disk by a motor mounted on the actuator. When an eject command is received, the actuator is moved to an inner crash stop and the disk is moved out of the reproduction position causing the locking mechanism to move into mechanical engagement with the actuator. A magnet carried on the locking means is moved adjacent a magnet within the motor so that the mechanical locking engagement is enhanced magnetically.

Abstract: A method and apparatus for initializing disk drive apparatus wherein a pickup head is positioned near the mid-range of tracks on a disk by moving the head at power-on to an innermost track and thereafter moving the head outwardly. As outward movement begins, a tracking error signal is sensed to indicate a track crossing, and the number of tracks crossed are counted until the head is at the mid-range of tracks. A velocity profile is used to speed movement of the head to its destination.

Abstract: The current mode sample-and-hold circuit includes a differential amplifier having a non-inverting input coupled to a first leg of a current mirror from which a first current to be sampled is drawn. An inverting input of the differential amplifier is coupled to its output and further coupled to a capacitor through a sample hold switch. The first current drawn from the first leg of the current mirror causes the capacitor to charge, through the differential amplifier. The charged capacitor is coupled to the current mirror and biases the current mirror so as to provide the required first current. Opening the sample hold switch causes the capacitor to maintain a bias level determined by the first current. The bias signal in turn causes a mirrored current flowing in a second leg of the current mirror to be maintained, even in the absence of the first current. Thus an input current is sampled and a corresponding output current is provided. The capacitor operates in a feedback loop for improving accuracy.

Abstract: A fluorescent dyed polymer member and a light source are structurally arranged in a manner to efficiently gather light from the light source and then transmit the gathered light to a light utilization device. Light from the light source is gathered over a large area that is occupied by the polymer member. This gathered light is transmitted through the polymer member to an edge portion thereof having a relatively small light emitting area. Light is then emitted as an external beam having a cross section that corresponds to the physical shape of the edge of the polymer member, for example a straight of linear footprint of light. The area brightness of this external beam is greater than the area brightness of the initial light source.

Abstract: A plurality of paper paths are established for recirculating cut sheets through an image transfer station as in color xerography. Cut sheets of a variety of possible lengths are repetitively fed through the image transfer station by selecting the recirculating paper path that allows maximum machine throughput speed The shortest paper path is established by the peripheral circumference of a drum. Additional paper paths are established by combinations of gates, conveyors and/or drums positioned and controlled for receiving copy sheets longer than the first drum can accommodate.

Abstract: Roll release mechanism for pinch rolls are improved by providing capability for axial and radial disengagement of the pinch rolls and automatic roll re-engagement upon machine activation. One set of pinch rolls is mounted on a first shaft with a helical cam thereon. A spring latch and pawl are engaged to the first shaft and attached to a second multi-radius shaft parallel to the first shaft. A second set of pinch rolls are mounted on the second shaft so as to engage the first set of pinch rolls. Axial movement of the second shaft results in shaft areas of different radius being fitted within bearings thereby disengaging the pinch rolls. Disengagement is maintained against a spring force by the catching of the pawl on the cam. Machine activation then results in rotation of the first shaft until the pawl is released from the cam and the spring force moves the second shaft axially until the pinch rolls have re-engaged. In addition, the pinch rolls may be re-engaged manually.

Abstract: An improved drive for a scanning optical system in a photocopier is disclosed. The drive incorporates an adjustable capstan and precision tapes as well as cables. The precision tapes are used between the two carriages which mount the optics because precise control of length in this portion of the system is critical. Cables are used in the remainder of the drive where flexibility in all directions is important. There is also a single drive embodiment. Also disclosed is a method for proper alignment of the carriages after field replacement of a broken cable.

Abstract: A sealing apparatus in a magnetic brush development device is located in a non-contact fashion between the photoconductor drum and the magnetic brush roll. The seal has a plurality of ridges along the length of the seal that creates a differential air flow under the rotating photoconductor drum. This differential air flow prevents toner dust and bead carryout from axially migrating past the end of the photoconductor and magnetic roll.

Abstract: Electronic alignment of paper feeding components in a machine such as an electrophotographic copier machine is achieved by placing an original master containing vernier calibrations on the document glass and a target master containing vernier calibrations in the copy paper bin. Thereupon, the machine is operated to produce a copy of the original master onto the target master producing a double set of vernier calibrations on the target master, which, when compared, provides information relating to skew angle, side edge relationship and leading edge alignment of the image to the copy paper. The vernier calibrations provide data which are keyed into a microprocessor controlled copy feeding servo mechanism to correct copy paper position and remove misalignment. The operation is repeated for various combinations of paper feed paths with techniques of original document placement and for duplex operation so that the copy paper matches image position for all modes of copier operation.

Abstract: A document feeder for automatically inverting a duplexed original so that the second side may be copied. The inverting mechanism is a turnaround roll located at the exit of the copy station. The inverting mechanism cooperates with rollers located above the document glass for moving documents thereacross. The rollers are inclined at an angle to the direction of paper movement in order to position paper against a side reference edge. When receiving a document from the turnaround roll and moving it in the reverse direction, the inclination of the rollers is removed or altered to a minus angle. Alternatively, a second set of rollers, inclined at a minus angle, are brought into active use when documents are moved in the reverse direction.

Abstract: A toner concentration control test cycle in which a developed test area is formed on a photoconductor charged to a dark charge level. The optical reflectivity of the developed test area is sensed and the result used to replenish toner if indicated. During the test cycle, the magnetic brush bias potential is altered to produce development of the test patch in the gray area with the level of dark charge held constant at a predetermined nominal level. An electrostatic probe and associated circuitry are provided to maintain dark charge at the nominal level during the test cycle.

Abstract: This invention relates to enhancing the apparent resolution of electrophotographic printers. This is accomplished by writing a gray of half-tone halo along the periphery of images written on the photoconductor. When the image with its half-tone halo is developed, transferred and fixed by steps in the electrophotographic process, the printed image has a substantially smooth contour. In effect, the gray halo placed around the image merges with the black interior of the image when the image is developed, transferred and fixed. To prevent the image from appearing to be too thick after its contour has been smoothed by the use of the half-tone halo, the number of black picture elements used to write the image on the photoconductor are reduced. Also, the width of image segments making up the image may be adjusted by changing the level of gray used to write the half-tone halo.

Abstract: A servo-controlled recirculating automatic document feeder (RADF) includes a plurality of independently driven document transport devices. A picker mechanism separates documents in seriatim from a stack. An entry turnaround transport device buffers and delivers picked documents to a platen transport device for exposure. After exposure, the document is transported along a simplex or duplex path for duplex or simplex copying. The document is then buffered in an exit turnaround transport device and is subsequently returned to the stack. Each transport device is independently driven by a motor and a closed-loop servo. A common reference oscillator generates source signals for the servo-loops. A microcomputer operates on the source signals and generates reference signals for driving the transport devices.

Abstract: A device for feeding sheets from a supply station aligning the sheets in an X, Y and .theta. coordinates and then gating the sheet into a work station such as the transfer station of a copier. The device includes a pair of independently servo-controlled motors disposed on opposite sides of the sheet. Each motor drives a nip roller which transports the copy sheet. Sensors are disposed to generate signals representative of sheet position in the X, Y and .theta. coordinates. A controller uses the signals to adjust the angular velocity of the motor so that the sheet is squared and is gated onto the work station. The sensors and controller are utilized to measure different parameters associated with the sheet.

Abstract: A document feed device, illustrated with a copier machine, for recirculating documents through a processing station. A movable portion of the document feed device is mounted for pivoting movement to expose a lower document feed path. The movable portion contains several document moving rollers but no prime movers, gears or belts; these rolls are driven by frictional contact with each other and ultimately by contact with a set of driven rollers located in the nonmoving portion of the document feed device. The rollers comprising a document moving nip are oppositely skewed relative to the direction of document travel in order to move documents gently toward a reference edge and coefficients of friction of roller materials are chosen to insure correct document alignment.

Abstract: A document copier machine with an automatic document feeder (ADF) combined with a semiautomatic document feeder (SADF) is operated according to a job recovery procedure in which multiple originals may need recopying in order to replace copies destroyed when a jam occurs. The procedure calls for feeding the required number of originals needed for recopy through the SADF and once the jam recovery is complete, automatic restarting of the ADF occurs in order to complete the job interrupted by the jam.

Abstract: In the use of a scanned light beam for optical imaging, a random motion modulation is applied to the light beam orthogonally to the scan direction to break up any unscanned or overlapped interstices between adjacent scan lines to make the interstices appear nearly invisible.

Abstract: An automatic vacuum document feeder particularly adapted for feeding sheet-like documents in seriatim from a stack onto a utilization device, such as the document platen of a convenience copier. The documents are disposed in a tray. A vacuum lifter descends and lifts the topmost document along a vertical path to a position above the stack and beyond the bottom surface of a vacuum transport. The vacuum transport is disposed in a plane perpendicular to the vertical path of the vacuum lifter. The vacuum transport strips the document from the vacuum lifter and transports the document to the utilization device. The entire system is configured so that there is no relative motion occurring between the document being transported and the transport hardware. A document restraint device, including air jets and stripper fingers, coact with the stack to eliminate double feed.