JPH0216659B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high voltage power supply device that switches between positive and negative high voltage output and supplies the high voltage output to a load.

Conventionally, high-voltage power supplies for equipment such as copying machines, which have a load that supplies a positive high voltage and a load that supplies a negative high voltage, separate the high-voltage output boosted by a single inverter transformer into positive and negative outputs. Alternatively, high-voltage outputs are generated separately for positive and negative voltages and then switched using high-voltage relays to supply the loads to each load. In such conventional devices, as shown in Figure 1, high-voltage output is It was something that could be changed. Figure 1 schematically shows an example of a conventional device that separates the high voltage output of an inverter into positive and negative parts and supplies it to a load.
T is the inverter transformer, _N2 is the high voltage output winding,
D ₁ and D ₂ are diodes connected to one end of winding N ₂ with opposite polarity, Re is a high voltage relay, A is an output detection section, B is a control section on the primary side of the inverter, and the voltage is boosted by a transformer T. The high voltage output is a high voltage relay
The signal is switched between positive and negative and supplied to the load by switching connection of diodes D ₁ and D ₂ by Re. In this way, conventional devices switch between positive and negative high voltage output on the high voltage side, so a high voltage relay is required for the switching relay, and in order to ensure reliable and stable operation, high costs cannot be avoided. Ta.

The present invention provides a highly reliable high voltage power supply device configured to switch between positive and negative high voltage output supplied to the same load on the low voltage side.
The configuration will be explained below using illustrated embodiments.
Both FIG. 2 and FIG. 3 show an embodiment of the present invention, and the same reference numerals indicate the same parts.

In the second illustrated embodiment, T is the inverter transformer, N ₁₁ is the first primary winding, and N ₁₂ is the second primary winding.
The secondary windings Tr1 and Tr2 are switching transistors for both of the primary windings, B ₁ and B ₂ are control units for each of the transistors Tr1 and Tr2, and
A first output winding N ₂₁ and a second output winding corresponding respectively to _{the primary winding N 11 and} the second primary winding N 12 of
N ₂₂ is provided, a diode D ₁ is connected in series to the first output winding N ₂₁ , a capacitor C ₁ and a resistor R ₁ are connected in parallel to constitute the first high voltage output section 1, and the second output winding
Capacitor C ₂ in parallel with diode D ₂ in series with N ₂₂
and resistor R ₂ constitute a second high voltage output section 2,
The diode D 1 of the first high-voltage output section ₁ and the diode D 2 of the second high-voltage output section ₂ have opposite polarities.
In addition, each of the first resistor R ₁ and the second resistor R ₂ is
Connect the end to the output terminal OUT and GND, and
The other ends are directly connected to each other, and both resistors R ₁ and R ₂ are connected in series. Note that D ₃ and D ₄ are diodes forming an output circuit according to the respective polarities of the first high-voltage output section 1 and the second high-voltage output section 2, and A ₁ and A ₂ are output detection sections.

Between the output terminals is a load to which positive and negative high voltages are switched and supplied, for example, a charging machine for a copying machine,
A single electrode for static elimination is connected to the low voltage side of the inverter, and an output for switching between positive and negative high voltage outputs generated by the first and second high voltage output sections by switching and driving transistors Tr1 and Tr2. Switching device S
will be established. This output switching device S performs a switching operation in synchronization with the point in time when a positive or negative high voltage should be supplied to the load, and for example, an electrode charges or removes static electricity as the drum of a copying machine rotates. The output switching device is operated in synchronization with the time, the first transistor Tr1 is turned on, and the first high voltage output section 1 supplies the positive high voltage across the capacitor _C1 to the load, and then the second transistor Tr1 is turned on. The transistor Tr2 is turned on and the second high voltage output section 2 supplies the negative high voltage across the capacitor _C2 to the load.
Note that the synchronization of the output switching device S with the timing of charging and neutralizing the electrodes according to the progress of rotation of the drum can be performed by an appropriate means. The capacitor C 1 of the first high-voltage output ₁ and the capacitor C ₂ of the second high-voltage output 2 have a resistance when the high voltage supply to the load is terminated and switched to the other.
It discharges through R ₁ , R ₂ , and also the detection parts A ₁ , A ₂ ,
Control units B ₁ and B ₂ detect the output of the inverter and control it to be constant. In this way, switching between positive and negative high voltage output is performed on the low voltage side of the primary side of the inverter, so the output switching device S does not need to take special measures for high voltage, and can adopt an appropriate circuit. Can be done.

FIG. 3 shows another embodiment of the present invention, in which the output winding N ₂₁ corresponding to the primary winding N ₁₁ of the inverter, the diode D ₁ , A first high-voltage output section 1 consisting of a capacitor C ₁ and a resistor R ₁ , an output winding N ₂₂ corresponding to the second primary winding N ₁₂ , a diode D ₂ , and a capacitor
C ₂ , a second high voltage output section 2 consisting of a resistor R ₂ ;
A first resistor R ₁ and a second resistor R ₂ are connected in series.
Tr is the switching transistor section on the primary side, B ₃
is its control part. In this embodiment, by switching the first and second primary windings N ₁₁ and N ₁₂ and connecting them to the input power supply by an output switching device consisting of a relay Ry and its driving part S _O , positive or negative Generates high voltage output. In this embodiment as well, positive and negative high voltage outputs are generated by switching on the low voltage side, so the output switching device consisting of the drive unit S _O and the relay Ry does not need to take any special measures against high voltages.

As described above, the present invention provides an output switching device on the low voltage side for switching the high voltage output between positive and negative in a power supply device that supplies a high voltage output obtained by boosting a low voltage input voltage to a load. There is no need to use a high-voltage relay, and reliable and stable operation can be easily performed, which not only improves reliability but also reduces costs. In addition, the high voltage output section is provided with a first and second positive and negative output section, and both the first and second high voltage output sections are connected to each other by a first resistor _R1 and a second resistor R1 of each output section. ₂ , it is possible to switch between both high voltage output sections using a single switching device on the low pressure side.
It is possible to easily realize switching supply of positive and negative high voltage outputs to the same load.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional high-voltage power supply device, and FIGS. 2 and 3 are drawings showing an embodiment of the present invention. 1: first high pressure output section, 2: second high pressure output section,
R ₁ : Resistor, R ₂ : Resistor, N ₂₁ : High voltage output winding,
N ₂₂ : High voltage output winding, S _O : Switching device, S _O , Ry: Switching device, L: Load.

Claims (1)

[Claims] 1. In a power supply device that supplies a high-voltage output obtained by boosting a low-voltage input voltage to a load, the first and second high-voltage output sections provided on the high-voltage side, the output switching device provided on the low-voltage side, and the first and second The second high-voltage output section includes first and second resistors that are provided in parallel with each output winding and connected to each other, and the output switching device switches between positive and negative high-voltage outputs. A positive/negative switching high voltage power supply device characterized by supplying a load with a positive/negative switching power source.