Abstract: Error compensation in a feedback servo system. The feedback servo loop in, for example, a head positioning circuit in an optical disk data recording and retrieval system is provided with a compensation signal to correct for misalignment or other errors. The head in such a system must be dynamically maintained at a best focus position but, through use and transporting, the alignment of the head position error detecting system can be disturbed. In some cases, the loop circuit parameters may drift from their original values. To correct for errors introduced from such causes, the head is positioned at best focus and the focus error (head position error) signal is sensed. A correction signal is supplied which cancels out the sensed value while the system is operating.

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 stapler mechanism for fastening variable thickness documents includes a stack receiving receptacle disposed between the head/hammer assembly and the clinching or anvil assembly of said stapler. A sensing device is coupled to the stapler mechanism and generates control pulses indicative of relative motion between the head/hammer assembly. A controller processes the signals and generates control signals which vary the stroke and the force driving the hammer and returns the head/hammer assembly to its home position following a stapling cycle.

Abstract: In a machine having a reciprocating original document handling carriage such as a copier, a selectively operable roller is positioned for removing documents from the upper surface of the carriage. The roller is driven by movement of the carriage by power stored from carriage movement or by an independent power source. Continuously driven rollers are positionable in coordination with the end of a run of copies for a given document to eject the document onto an output tray as the carriage returns.

Abstract: In a machine having a reciprocating original document handling carriage such as a copier, a roller at the bottom of a sloped ramp rests on the upper surface of the carriage. Documents placed on the ramp slide downward until the leading edge is at the nip between the roller and carriage surface. Movement of the carriage pulls the document from the tray onto the carriage surface for scanning. An additional roller can be included to provide automatic document ejection by pushing the document onto an output tray as the carriage returns.

Abstract: A forward/backward compatible apparatus and record member achieves multiple density by multiple track widths as well as multiple lineal densities. In a rotating head recorder a single head has a wide write gap followed by a plurality of narrow read gaps. In recording, narrower tracks--i.e., higher densities, the record medium is moved less than the width of the write gap for recording narrower tracks. The narrower tracks have the same width as the trailing read gaps. During readback, all read gaps are simultaneously operative. Signals from one of the read gaps are processed immediately, while signals from the remaining read gaps are buffered until a dead time occurs, such signals are then processed. The same principles are applicable to magnetic card and magnetic disk recorders. A record member of the disclosure employs a table of contents area always recorded at the lower density--i.e., widest track.

Abstract: In a helically scanned device, a length of flexible media, with transverse data tracks thereon, is positioned relative to a rotating transducer. The transducer coacts with the media to transduce data therefrom. The transducer is coupled to a piezoelectric bender. Periodically, the instantaneous position of the transducer is monitored and an error signal is generated. The error signal is used to drive the piezoelectric bender so that the transducer follows the data track.

Abstract: In a rotating head magnetic tape transport, the tape is maintained stationary as the head sweeps a selected data track. A length of tape is buffered in a vacuum column between a supply spool and a rotating head station. A take-up spool on the opposite side of the head station is controlled by minimizing the overshoot or undershoot of the motor driving the take-up spool as the radius of the amount of tape on the spool increases or decreases (i.e., change). After a step operation, the overshoot or undershoot of the motor is measured and compared with a reference range to determine if the undershoot or overshoot is within the reference range. If the measured quantity is within the reference range, no adjustment is made. If the measured quantity is outside of the voltage level or reference range, the gain of the take-up motor is adjusted.

Abstract: An elongated magnetic tape has a pair of longitudinally extending servo track areas, one of which is closer to the longitudinal center of the tape than the other. The lateral space intermediate the servo areas receives data signals, while the space between said one servo area and one edge contains identification and address signals. The tape is particularly adapted for use with rotating head recorders having two gaps on the rotor, with an intergap distance slightly greater than the lateral extent of the servo areas. A recording or write gap precedes an immediately trailing reading or recovery gap. When the rotor gaps pass the one edge in the one servo area, the write gap senses the servo track; while the read gap senses the identification signals. The arrangement is such that prior to the time the write gap reaches the data recording area, the read gap has sensed the identification signals.

Abstract: An elongated magnetic tape has a pair of longitudinally extending servo track areas, one of which is closer to the longitudinal center of the tape than the other. The lateral space intermediate the servo areas receives data signals, while the space between said one servo area and one edge contains identification and address signals. The tape is particularly adapted for use with rotating head recorders having two gaps on the rotor, with an intergap distance slightly greater than the lateral extent of the servo areas. A recording or write gap precedes an immediately trailing reading or recovery gap. When the rotor gaps pass the one edge in the one servo area, the write gap senses the servo track; while the read gap senses the identification signals. The arrangement is such that prior to the time the write gap reaches the data recording area, the read gap has sensed the identification signals.