Abstract: A humidity-adjusted power supply includes a power supply circuit (e.g., relatively higher-voltage circuit) connected to a printed circuit board. The power supply circuit is adapted to provide output voltage to a voltage load. The humidity-adjusted power supply also includes a humidity control circuit (e.g., relatively lower-voltage circuit) connected to the printed circuit board adjacent the power supply circuit. The humidity control circuit outputs a heater control signal to a heater that is also connected to the printed circuit board. The heater is in a location to receive the heater control signal from the humidity control circuit. The power supply circuit and the humidity control circuit are positioned, relative to each other, on the printed circuit board to experience the same environmental conditions.

Abstract: Apparatuses include a voltage divider that is connected to a current source, a humidity sensor within an internal humid location of an apparatus, and an amplifier connected to the voltage divider and the humidity sensor. The humidity sensor produces a current signal that increases with increases in the humidity level and the amplifier amplifies the signal produced by the humidity sensor to produce compensating output current. The amplifier provides amplification of the signal produced by the humidity sensor at a level that increases with increases of the primary output current. Thus, the amplifier provides the amplification of the signal produced by the humidity sensor at a level to make the compensating output current equal to the leakage current. This causes the electrical load element to receive the primary output current combined with the compensating output current as a power supply current that is unaffected by the leakage current.

Abstract: Apparatuses include a voltage divider that is connected to a current source, a humidity sensor within an internal humid location of an apparatus, and an amplifier connected to the voltage divider and the humidity sensor. The humidity sensor produces a current signal that increases with increases in the humidity level and the amplifier amplifies the signal produced by the humidity sensor to produce compensating output current. The amplifier provides amplification of the signal produced by the humidity sensor at a level that increases with increases of the primary output current. Thus, the amplifier provides the amplification of the signal produced by the humidity sensor at a level to make the compensating output current equal to the leakage current. This causes the electrical load element to receive the primary output current combined with the compensating output current as a power supply current that is unaffected by the leakage current.

Abstract: An apparatus to monitor a condition of a solid state charge device (SSCD) useful in electrostatic printing includes a power supply and a frequency detector. The power supply provides current to the SSCD, and includes a resonant controller. The frequency detector senses a frequency associated with the current, and since the frequency is representative of the condition of the SSCD, the frequency detector thereby monitors the condition of the SSCD. A method of monitoring the condition of the SSCD includes providing current to the SSCD using a power supply, and sensing a frequency associated with the current. The power supply includes a resonant controller, and the frequency is representative of the condition of the SSCD, and thus the method thereby monitors the condition of the SSCD. A corresponding computer-readable medium is also disclosed.

Abstract: An apparatus to monitor a condition of a solid state charge device (SSCD)) useful in electrostatic printing includes a power supply and a frequency detector. The power supply provides current to the SSCD, and includes a resonant controller. The frequency detector senses a frequency associated with the current, and since the frequency is representative of the condition of the SSCD, the frequency detector thereby monitors the condition of the SSCD. A method of monitoring the condition of the SSCD includes providing current to the SSCD using a power supply, and sensing a frequency associated with the current. The power supply includes a resonant controller, and the frequency is representative of the condition of the SSCD, and thus the method thereby monitors the condition of the SSCD. A corresponding computer-readable medium is also disclosed.

Abstract: This disclosure provides power supply control methods and apparatus. According to one aspect of the disclosure, a method of operating a power supply operatively connected to a developer unit associated with a printing apparatus is disclosed. The method includes generating a modified output control signal as a function of stored gain and offset values associated with the power supply to generate a desired output voltage to drive the developer unit.

Abstract: This disclosure provides power supply control methods and apparatus. According to one aspect of the disclosure, a method of operating a power supply operatively connected to a developer unit associated with a printing apparatus is disclosed. The method includes generating a modified output control signal as a function of stored gain and offset values associated with the power supply to generate a desired output voltage to drive the developer unit.

Abstract: A current measurement circuit to measure the output of a power supply transformer includes a simulation capacitor having a capacitance proportional to a parasitic capacitance of the transformer. The first electrode of the capacitor is coupled to an output winding of the transformer and the second electrode is coupled to a first node, with a second sense resistor coupled between the first node and ground so that current flowing through the simulation capacitor flows through the second sense resistor. Current flowing through a first sense resistor coupled to a second node and to ground has a component representative of the output current of the power supply and a component representative of the parasitic current. A differential amplifier coupled at an inverting input to the first node and at a non-inverting input to the second node generates an output signal that is proportional to the output current of the power supply.

Abstract: A power supply is modified with a current measurement circuit to measure the output of the power supply having a transformer exhibiting a parasitic capacitance.

Abstract: A printer apparatus includes a photoreceptor, a magnetic roll, an electrode, a current source coupled to the electrode, the current source having a signal generator coupled to an input winding of a transformer that exhibits a parasitic capacitance; and a current measurement circuit. The current measurement circuit includes a simulation capacitor having a capacitance proportional to the parasitic capacitance, the simulation capacitor having a first electrode coupled to a hot terminal of the output winding of the transformer and a second electrode coupled to a first node, a second sense resistor coupled between the first node and ground so current flowing through the simulation capacitor flows through the second sense resistor, a first sense resistor coupled to a second node, and a differential amplifier having an inverting input coupled to the first node and a non-inverting input coupled to the second node.