Abstract: A scanning system for use in an imaging apparatus includes a mirror assembly having a rotating mirror with a plurality of facets, a motor operatively coupled to the rotating mirror and closed loop control circuitry coupled to the motor. The mirror assembly generates a lock signal indicative of whether or not the motor is substantially at a target speed. A controller is communicatively coupled to the mirror assembly for controlling rotation of the rotating mirror, the controller generating a reference signal received by the motor assembly indicating the target speed for the rotating mirror. The reference signal is varied based at least in part upon an acceleration profile that accelerates the motor so that overshoot of the target speed is substantially reduced.

Abstract: A scanning system for use in an imaging apparatus includes a mirror assembly having a rotating mirror with a plurality of facets, a motor operatively coupled to the rotating mirror and closed loop control circuitry coupled to the motor. The minor assembly generates a lock signal indicative of whether or not the motor is substantially at a target speed. A controller is communicatively coupled to the minor assembly for controlling rotation of the rotating mirror, the controller generating a reference signal received by the motor assembly indicating the target speed for the rotating minor. The reference signal is varied based at least in part upon an acceleration profile that accelerates the motor so that overshoot of the target speed is substantially reduced.

Abstract: An electrically isolated temperature sensor for use with a printer, copier, or all-in-one fuser. The fuser includes an AC driven heater to which a thermistor is mounted for sensing the temperature of the fuser heater. A resistance of the thermistor controls the period of a periodic signal generated by an astable multivibrator. An optical isolator isolates the printer fuser from down line processing circuits, and transfers the periodic signal to such processing circuits. The printer fuser employs a separate floating ground that is not connected to other DC circuits of the printer. With this arrangement, any AC power that is inadvertently coupled from the heater to the DC circuits of the fuser is isolated thereto. The AC power is isolated to the fuser and cannot be propagated through the fuser to other down line circuits of the printer.

Abstract: An electrically isolated temperature sensor for use with a printer, copier, or all-in-one fuser. The fuser includes an AC driven heater to which a thermistor is mounted for sensing the temperature of the fuser heater. A resistance of the thermistor controls the period of a periodic signal generated by an astable multivibrator. An optical isolator isolates the printer fuser from down line processing circuits, and transfers the periodic signal to such processing circuits. The printer fuser employs a separate floating ground that is not connected to other DC circuits of the printer. With this arrangement, any AC power that is inadvertently coupled from the heater to the DC circuits of the fuser is isolated thereto. The AC power is isolated to the fuser and cannot be propagated through the fuser to other down line circuits of the printer.

Abstract: A system for driving a torsion based on frequency, amplitude and offset control signals includes a pulse width modulator subsystem configured to generate output pulses having controlled pulse durations alternately to each of two channels, the output pulses encoding the frequency, amplitude and offset control signals. A driver circuit is configured for driving the torsion oscillator with a voltage of one polarity during a pulse output to the one of the channels, and a voltage of opposite polarity during a pulse output to the other of the channels.

Abstract: A system for driving a torsion oscillator based on frequency, amplitude and offset control signals includes a pulse width modulator subsystem configured to generate a stream of repetitive pulse signals which encodes the frequency, amplitude and offset control signals, a low pass filter for filtering the stream of repetitive pulse signals to provide a filtered output, and a driver circuit for driving the torsion oscillator based on the filtered output.

Abstract: An improved laser printer is provided that keeps its fuser at a standby temperature that is somewhat raised above the ambient temperature, which allows the printer to operate more quickly (to begin printing the first page) when a print job arrives at the printer. The time needed to raise the fuser's temperature is minimized, so that other printer operations become the determining factor in the time to first print parameter. The electrical energy that energizes the fuser is provided in a form that prevents light flicker, by use of AC waveform phase control, or by use of integer half cycle control. The present invention uses closed-loop feedback control, and the type of controller is a PID controller.

Abstract: A resistive heater adapted for heating a fuser belt is provided. The heater comprises a substrate, a first resistive trace formed over the substrate, and a second resistive trace formed so as to at least partially overlap the first resistive trace.

Abstract: A circuit includes a switching device for controlling a power signal to be applied to a heating device. A control circuit is configured for comparing a temperature signal, indicative of the temperature of the heating device, to a temperature setpoint to generate a gate pulse signal that controls the duration of the power signal to be applied to the heating device. The control circuit is further configured for comparing the duration of the power signal to be applied to the heating device to a minimum pulse duration and, if the duration of the power signal to be applied to the heating device is at least equal to the minimum pulse duration, providing the gate pulse signal to the switching device.

Abstract: A resistive heater adapted for heating a fuser belt is provided. The heater comprises a substrate, a first resistive trace formed over the substrate, and a second resistive trace formed so as to at least partially overlap the first resistive trace.

Abstract: An improved control method is provided that combines conventional ON-OFF control and conventional phase-angle control to reduce the AC inrush current to an electrical load, such as a tungsten halogen lamp used as a heating element in a laser printer, so that the power control circuit can satisfy both the European flicker and European harmonic requirements. Phase-angle control is applied to the load for a very short time period when it is initially energized, then the control circuit quickly switches from phase-angle control to standard ON-OFF control to reduce the harmonics generated by conventional phase-angle control methodologies. The electrical load exhibits three possible states: power full OFF, power ramp-up, and power full ON. During the power ramp-up state, power supplied to the load is adjusted by delaying the phase angle of the firing pulse relative to the start of each AC half cycle.