Corona voltage supply for use in electrostatic copier

Claim 2

For use in an electrostatic copier having a corona charging unit, a corona developer unit, and a corona transfer unit, a power supply for supplying an isolated potential to each one of said corona units, said power supply comprising a transformer having a primary circuit and a secondary circuit, said secondary circuit having one side connected to a reference potential, and means for electrically isolating each one of said corona units from remaining ones of said corona units to prevent voltage fluctuations appearing at any one of said corona units from being communicated to any of the other said corona units through said power supply, said isolating means including a plurality of unidirectional conducting devices, each having an input terminal and an output terminal, the input terminal of each of said plurality of unidirectional conducting devices being directly connected to the other side of said secondary circuit at a common junction, the output terminals of each of said plurality of unidirectional conducting devices being directly connected to a separate one of said corona units.

Claim 3

The apparatus of claim 1 wherein at least one of said unidirectional conducting devices is poled in a direction opposite that of the remaining ones of said unidirectional conducting devices.

Claim 4

The device of claim 1 wherein each of said unidirectional conducting devices comprises a diode having an anode and a cathode.

Claim 5

The apparatus of claim 3 wherein said diodes are poled to provide a high negative potential to said corona charging unit and said corona transfer unit, and a high positive potential to said corona developer unit.

Claim 6

The apparatus of claim 4 wherein said cathode of each of said diodes poled to provide a high negative potential is directly connected to said common junction and said anode of each of said diodes poled to provide a high positive potential is directly connected to said common junction.

Claim 7

The apparatus of claim 1 further including a capacitor coupled between said output terminal of at least one of said plurality of unidirectional conducting devices and said reference potential.

Claim 8

The apparatus of claim 1 further including a plurality of capacitors coupled between said reference potential and said plurality of output terminals, each one of said plurality of capacitors being connected to a different one of said output terminals.

Claim 9

A power supply for providing isolated high potential to a corona charging unit, a corona developer unit, and a corona transfer unit in an electrostatic copier, said power supply comprising a transformer having a primary circuit and a secondary circuit, a plurality of output terminals, each of said plurality of output terminals adapted to be connected to a different one of said corona units and means for electrically isolating each of said output terminals from remaining ones of said output terminals, said last-named means including a plurality of unidirectional conducting devices each having an input terminal and an output terminal, said input terminal of each of said unidirectional conducting devices being directly connected to a first side of said secondary circuit at a common junction, said output terminal of each of said unidirectional conducting devices being directly connected to a different one of said power supply output terminals, at least one of said unidirectional conducting devices being poled in a direction opposite that of the remaining ones of said unidirectional conducting devices, the other side of said secondary circuit being connected to a reference potential.

Claim 10

A power supply for providing isolated high potential to a corona charging unit, a corona developer unit, and a corona transfer unit in an electrostatic copier, said power supply comprising a transformer having a primary circuit and a secondary circuit, a plurality of output terminals, each of said plurality of output terminals adapted to be connected to a different one of said corona units and means for electrically isolating each of said output terminals from remaining ones of said output terminals, said last-named means including a plurality of unidirectional conducting devices each having an input terminal and an output terminal, said input terminal of each of said unidirectional conducting devices being directly connected to a first side of said secondary circuit at a common junction, said output terminal of each of said unidirectional conducting devices being directly connected to a different one of said power supply output terminals, at least one of said unidirectional conducting devices being poled in a direction opposite that of the remaining ones of said unidirectional conducting devices, the other side of said secondary circuit being connected to a reference potential.

Claim 11

The apparatus of claim 8 further including a plurality of capacitors coupled between said output terminal of said unidirectional conducting devices and said reference potential, each one of said plurality of capacitors being coupled to a different one of said output terminals.

Claim 12

The apparatus of claim 8 wherein each one of said unidirectional conducting devices comprises a diode having an anode and a cathode.