Abstract: A sheet detection system comprising: a first sheet transport for transporting a sheet along a first sheet transport path; at least second and third sheet transports for selectively transporting a sheet transported along the first sheet transport path along second and third spaced and substantially parallel sheet transport paths which branch from the first sheet transport path; a radiation source for emitting a beam of radiation which intersects the second and third sheet transport paths in the region where the second and third paths branch from the first path; a radiation detector for detecting the radiation beam; and a control for controlling the first, second and third sheet transports the radiation source and the radiation detector, such that when a sheet which is transported along the first sheet transport path by the first sheet transport is caused to be transported along one of the second or third transport paths, interruption or lack of interruption of the radiation beam by the sheet is detected by the

Abstract: A sheet detection system comprising: a first sheet transport for transporting a sheet along a first sheet transport path; at least second and third sheet transports for selectively transporting a sheet transported along the first sheet transport path along second and third spaced and substantially parallel sheet transport paths which branch from the first sheet transport path; a radiation source for emitting a beam of radiation which intersects the second and third sheet transport paths in the region where the second and third paths branch from the first path; a radiation detector for detecting the radiation beam; and a control for controlling the first, second and third sheet transports the radiation source and the radiation detector, such that when a sheet which is transported along the first sheet transport path by the first sheet transport is caused to be transported along one of the second or third transport paths, interruption or lack of interruption of the radiation beam by the sheet is detected by the

Abstract: A thermal processor for thermally processing a sequence of exposed photothermographic media comprising: a rotatable thermally conductive drum; a heat source for heating the drum to a setpoint temperature; a plurality of rollers spaced around a portion of the periphery of the drum for holding down exposed photothermographic media to the drum for thermal development thereof; a sensor for sensing the temperature of the drum; and a control for controlling the temperature of the drum as a function (1) of the setpoint temperature, (2) of the sensed drum temperature, and (3) of the status of the processor, i.e., whether or not photothermographic media is being processed by the drum, in order to compensate for heat loss due to media heating and roller heating.

Abstract: A shutter, positioned between an electronic imaging device (such as a laser printer) and a film processor, is actuated by a solenoid which is driven by a driver network which isolates the solenoid coil when it is deactuated. If, after deactuation, a jam occurs, such that the shutter does not close completely, the jam is detected by a solenoid engagement sensing circuit. The sensing circuit includes a function generator, an operational amplifier having the solenoid coil connected between its input and output, an envelope detector and a comparator. The comparator produces a jam signal in response to an increase in the voltage detected by the presence of the solenoid plunger within the solenoid coil.

Abstract: In a disk memory library, picker arms, operated by a solenoid, are used to remove a selected disk from a library stack of disks and to place the disk in a reading/writing environment. The solenoid plunger's position is determined by noting its effect on a series resonant circuit that is formed with the coil inductance of the solenoid coil and a series capacitor. A function generator provides a triangular signal to the solenoid coil. An amplifier and peak detector are coupled to the coil to amplify and peak detect the voltage signal across the coil. A threshold detector, coupled to the output of the peak detector, is set to provide a digital output indicating when the solenoid's plunger is in or out. The function generator also provides a square wave that is synchronized to the triangle wave and is coupled to sample the output from the threshold detector. The change in the coil's inductance causes a phase shift in the triangle wave which further accentuates the voltage difference appearing across the coil.