Abstract: A combined charge/recharge xerographic power supply is provided that utilizes one power supply to drive the charge pin scorotron and recharge discorotron grids of a electrophotographic or xerographic system. The power supply uses recycled power from the pin scorotron grid to drive the discorotron grid. In particular, the power supply uses power that is dissipated in the traditional shunt regulator attached to the pin scorotron grid terminal to drive and provide active current to the discorotron grid through a series-pass regulation circuit. Thereby providing reduced electromagnetic emissions and reduced unit manufacturing costs.

Abstract: A combined charge/recharge xerographic power supply is provided that utilizes one power supply to drive the charge pin scorotron and recharge discorotron grids of a electrophotographic or xerographic system. The power supply uses recycled power from the pin scorotron grid to drive the discorotron grid. In particular, the power supply uses power that is dissipated in the traditional shunt regulator attached to the pin scorotron grid terminal to drive and provide active current to the discorotron grid through a series-pass regulation circuit. Thereby providing reduced electromagnetic emissions and reduced unit manufacturing costs.

Abstract: A parameter which is a function of ionization voltage of a first ionization device is displayed and/or used to control the ionization voltage of a second ionization device in accordance with altitude, pressure, or humidity. The first device can be a DC ionization device, e.g., a scorotron, while the second device can be an AC ionization device, e.g., a discorotron or a dicorotron. A third ionization device can also have its ionization voltage controlled by the first device ionization voltage. The invention can be used in a xerographic apparatus.

Abstract: A method of achieving pure tone noise control in a charging system of a copier/printer. The method includes the steps of first providing a plurality of individual charging devices and providing a plurality of power supplies for charging the plurality of individual charging devices. Next, charging at least one of the plurality of individual charging devices with a first of the plurality of power supplies at a predetermined frequency and charging at least one of the plurality of individual charging devices with a second of the plurality of power supplies at a frequency different from, but within a band width of, the predetermined frequency; and, lastly, charging at least one of the plurality of individual charging devices with a third of the plurality of power supplies at a frequency different from that of the first and second power supplies and within the band width of the first power supply frequency.

Abstract: A method and apparatus for achieving optimum noise control of multiple coronode wires in a copier/printer involves optimizing phase relationships of the voltage on the wires in such a way so as to steer the maximum part of the noise distribution profile in the direction best suited for absorption or dissipation. In a two corotron charging system, the coronodes are preferably charged to where the phase angle, charge frequency and spacing between wires are optimized. If desired, a sound absorption material could be added to the charging system.

Abstract: A toner concentration sensor is located adjacent a transport auger within the developer sump. The toner concentration sensor projects from the bottom wall of the developer sump towards the transport auger to an extent that the sensor overlaps with the blade of the auger. A portion of the auger blade is notched to avoid contact between the auger blade and toner concentration sensor. The position of the sensor allows for accurate toner concentration sensing due to the active flow of toner material across the surface of the sensor.