Abstract: A method and device for reducing the maximum torque to rollers mounted on a drive shaft of a drive roller assembly. By using a plurality of slip clutches, each for engaging an individual roller to the drive shaft and setting a maximum torque for the individual rollers, each roller is coupled to the drive shaft when the tangential force exerted on the roller does not exceed the maximum torque, and each roller is mechanically decoupled from the drive shaft when the tangential force exerted on the roller exceeds the maximum torque. Because each roller has a separate slip clutch, each roller can be mechanically decoupled from the drive shaft without affecting the other rollers coupled to the drive shaft.

Abstract: A power control method and apparatus maintains a constant average power at an electrical load, such as a fuser in an electrophotocopy machine. A power monitor measures the average power delivered to the load and compares the measured power to a predetermined power. A digital network receives an input signal from the power monitor and controls the coupling of power from an ac source to the load. When load power is less than a predetermined level, the digital network couples every half cycle of the ac power source to the load. When the load power is equal to or greater than the predetermined power, the digital network couples every third ac half cycle to the load. As a result, only half cycles of sequentially opposite polarity are coupled to the load.

Abstract: A system for continuously transporting individual articles or a succession of uniformly-spaced articles on a moving conveyor surface through one or more work stations and for providing a warning signal when the normal location of any one of said articles changes relative to said conveyor surface by more than a predetermined permissible distance at a predetermined work station where such changes in spacing are most objectionable or dangerous. The system comprises a pulse-supplying means or machine clock for supplying pulses having a variable frequency proportional to the rate of movement of the conveyor surface, a delay means for providing a conveyor displacement signal when said conveyor surface has moved a predetermined distance and sensing means activated by each of said articles as they travel said predetermined distance to provide an article travel time signal.

Abstract: A solenoid drive circuit to enhance the operation of an alternating current solenoid. The circuit supplies alternating current to the solenoid when its plunger is in an extended position and then switches to a direct current when the plunger is in its home position, thereby eliminating any buzzing due to plunger misalignment or other inherent characteristics of the solenoid or associated mechanism and drawing less power than if it was being held in its home position with alternating current voltage. The invention has wide applicability but is disclosed herein in association with the operation of a fail-safe device, particularly a device to prevent fires from starting in a radiant energy fixer of an electrostatic copying machine in the event of a sudden loss of power.

Abstract: A circuit for detecting documents jammed at the entry to an image fixing station in a copier includes a latch-controlled timer. Energization of a paper feed clutch sets the latch to initiate a timing cycle. A photoelectric circuit indicates whether the trailing edge of a document being fed to the image fixing station has cleared the entry. The proper output from this circuit clears the latch and interrupts the timing cycle. If the timer times out before the entry is cleared, the timer output is driven to a jam-indicating state.