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US 4,868,729 AGranted
Power supply unit
AssigneeCanon Kabushiki Kaisha
InventorKoji Suzuki
Life of this patent
Estimating the term…
Abstract
A power supply unit for an electrostatic printing apparatus such as a copying machine is disclosed. A transformer is driven by a drive circuit having a pulse generator and produces a high voltage in the course of decay of a pulse. An output of a secondary winding of the transformer is detected to control the drive circuit such that the output of the secondary winding is kept at a constant level.
Claims16
A high voltage power supply unit comprising:
- a transformer having a single secondary winding which has a plurality of output circuits for providing high voltage outputs to drive a plurality of loads;
- drive means including a primary winding of said transformer for driving said transformer;
- a pulse generator for actuating said drive means;
- deduction means for detecting the amount of current flowing into a predetermined load connected to a secondary winding output of said transformer, through an element electrically insulated from said predetermined load;
- and
- control means for controlling an output current of a predetermined one of said plurality of output circuits to a constant level in accordance with a detection output of said detection means;
- wherein said drive means includes a resonant circuit resonating with an output of said pulse generator for driving said transformer to provide said high voltage, and wherein said drive means has a first function for storing energy at the primary winding of said transformer to provide said high voltage output at the output circuits of said transformer and a second function for emitting the stored energy.
4 more elements
A power supply unit comprising:
- a transformer having a plurality of secondary winding output circuits for providing high and low voltage outputs to drive a plurality of loads;
- drive means including a primary winding of said transformer for driving said transformer;
- a pulse generator for actuating said drive means;
- detection means for detecting the amount of current flowing into a load connected to a secondary winding output of said transformer;
- adding means for adding a direct current source to at least one of said plurality of secondary winding output circuits;
- and
- control means for controlling said adding means to stabilize an output of a predetermined one of said plurality of secondary winding output circuits to a constant level in accordance with a detection output of said detection means;
- wherein said drive means includes a resonant circuit resonating with an output of said pulse generator for driving said transformer to provide said high and low voltages, and wherein said drive means has a first function for storing energy at the primary winding of said transformer to provide said high and low voltage outputs at the secondary winding output circuits of said transformer and a second function for emitting the stored energy.
5 more elements
Dependencies are inferred from the claim text.