JP2001224167A - High-voltage power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-voltage power supply unit, capable of forming the output of another high-voltage generating means into a prescribed high- voltage output by detecting a high-voltage output value, which is a reference of high-voltage control and for determining an abnormally dropped output or an abnormally operating condition, based on the outputted value. SOLUTION: This high-voltage power supply unit is provided with the high- voltage generating means 1 including a drive means 5 of driving a transformer T1 which generates first high voltage, a pulse width control means 3 for controlling the output, and a detecting means 7 for detecting the output, and the high- voltage generating means 2 including a transformer T2 for generating second high voltage, and the drive means 6 which is driven by the pulse width control means 3 and drives the transformer T2, includes a detecting means 8 for detecting the output of the transformer 2, an abnormality detecting means 11 for detecting abnormality with the detecting means 7, 8 and stopping the input of the drive means 5, 6 having a pulse width control means, and a high- level preference means 10 for selecting the detecting means 7, or 8 which detects high level, if one output of the high-voltage generating means drops, and for controlling the drive means 5, 6 with the pulse width control means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage power supply suitable for supplying a high voltage to a high voltage load device such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer has a plurality of high voltage generating means. Each of the high voltage generating means has a predetermined voltage value or current value with respect to a corresponding high voltage load device. Are controlled by respective pulse width control means.

Normally, pulse width control means are required for the number of high voltage generation means. However, in order to reduce the number of circuit components and reduce costs, the control pulse signal of one high voltage generation means is transmitted to another high voltage generation means. Is used to control the high-voltage output by using the driving pulse as a driving pulse. FIG. 2 is a block diagram showing a configuration of a conventional high-voltage power supply device used for an image forming apparatus and the like. As shown in FIG. 2, the high-voltage power supply device drives the first driving means 5 by the control pulse signal of the pulse width control (PWM) means 3 driven by the high-voltage output signal in the first high-voltage generating means 1. A first high-voltage load L1 is generated by generating a high voltage by the first transformer means T1.
And the second driving means 6 of the second high voltage generating means 2 is driven by the control pulse signal of the pulse width control means 3 to generate a high voltage by the second transformer means T2. The high-voltage power is supplied to the second high-voltage load L2.

At this time, since the output control pulse signal of the pulse width control means 3 may similarly change due to a remarkable change in the load condition of the high voltage generation means, a relatively high voltage generation means is used. A high-voltage load having a small number of fluctuation elements, for example, the first high-voltage generating means 1 having the first high-voltage load L1 is selected, and an output voltage as an output amount is detected by an output voltage detecting means 7 to control the pulse width control means 3. It is an input signal.

[0005]

However, due to external factors such as abnormalities in the circuit and load, the pulse in the first high-voltage generating means 1 serving as a reference for the high-voltage control during operation of the high-voltage power supply or the like. The control pulse signal of the width control means 3 stops (off) or continues to operate (remains on)
In such a state, the output voltage as the output amount of the second high-voltage generating means 2 simultaneously using the control pulse signal is also affected by this, and becomes lower or unstable.

FIG. 3 is a diagram illustrating the operation of the high-voltage power supply device shown in FIG.

That is, as shown in FIG. 3A, when the high voltage output voltage V1 of the high voltage generating means 1 is normal, the control value of the pulse width control means 3 is normal and each of the high voltage generating means 1, 2 The high output voltages V1 and V2 have predetermined control values. However, if the high-voltage output voltage V1 of the high-voltage generating means 1 rises abnormally ((b) in the figure) or falls abnormally ((c) in the figure) due to a circuit or load fluctuation, an abnormal high-voltage control state (overvoltage) Or insufficient voltage), and the output voltage V2 of the high voltage generation means 2
Since the pulse signal of the pulse width control means 3 is the same, there is a problem that the voltage rises and drops like the output voltage V1 of the high voltage generation means 1.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and detects a high-voltage output value serving as a reference for high-pressure control, and determines an abnormally low output or an abnormal operation state based on the output value. It is another object of the present invention to provide a high-voltage power supply device in which the output of another high-voltage generating means is set to a predetermined high-voltage output.

[0009]

In order to achieve the above object, a high-voltage power supply according to claim 1 of the present invention comprises a first transformer for generating a first high voltage, and the first transformer. A first detecting means for detecting an output of the means, a first driving means for driving the first transformer means, and controlling the first driving means based on an output of the first detecting means. A first high voltage generating means having pulse width control means for controlling an output of the first transformer means, a second transformer means for generating a second high voltage; And a second driving means for controlling an output of the second transformer means by driving a second transformer means. The second transformer hand provided A second detecting means for detecting the output of the first detecting means, the first detecting means, the second detecting means, and the pulse width controlling means. The second detecting means is provided by the first and second detecting means. An abnormality detecting means for detecting an abnormality of the second high-pressure generating means and stopping the operation of the pulse width controlling means; and a first detecting means, a second detecting means, and a pulse width controlling means. And when the output of one of the first and second high-voltage generating means decreases, the first or second
And high-level priority means for selecting an output from the detection means having detected a high level among the detection means and inputting the selected output to the pulse width control means to control the first and second driving means. I do.

A high-voltage power supply according to a second aspect is the high-voltage power supply according to the first aspect, wherein the high-voltage power supply includes first high-voltage generation means and at least one or more second high-voltage generation means.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the configuration of a high-voltage power supply according to the present invention. still,
In the high-voltage power supply shown in FIG. 1, the same components as those in the high-voltage power supply shown in FIG. 2 are denoted by the same reference numerals. As shown in FIG. 1, the first high-voltage generating means 1 of the high-voltage power supply device is a switch of the first driving means 5 provided at one end of the primary winding of the first transformer means T1 by the pulse width control means 3. The transformer means T1 is driven by turning on / off the element FET Tr1. A DC voltage (DC voltage) B1 is input to the other end of the primary winding of the transformer means T1. The high-frequency voltage generated on the secondary side of the transformer means T1 is rectified by the capacitor C1 and the diode D1, and applies a positive high-voltage output voltage V1 to the external first high-voltage load L1. The output voltage V1 of the first high-voltage generating means 1 is divided by the resistors R1 and R2 at the output end to obtain a first output voltage detecting means 7.
To detect.

Similarly, the second high pressure generating means 2
The pulse width control means 3 turns on / off the switching element FET Tr2 of the second drive means 6 provided at one end of the primary winding of the transformer means T2 to drive the second transformer means T2. . A DC voltage (DC voltage) B2 is input to the other end of the primary winding of the transformer means T2. The high frequency voltage generated on the secondary side of the transformer means T2 is
A positive high-voltage output voltage V2 is rectified by the capacitor C2 and the diode D2 and applied to the external second high-voltage load L2. The output voltage V2 of the second high voltage generating means 2 is divided by the resistors R4 and R5 at the output end and detected by the second output voltage detecting means 8. The resistor R3 connected between the high-voltage generating means 1 and the high-voltage load L1 and the resistor R6 connected between the high-voltage generating means 2 and the high-voltage load L2 are:
This is a resistor for limiting current.

The output voltages of the first output voltage detecting means 7 and the second output voltage detecting means 8 are applied to the pulse width control means 3 via the high level priority means 10 and the abnormality detecting means 11.
Connect to The high-level priority unit 10 compares the voltage input from the first output voltage detection unit 7 with the voltage input from the second output voltage detection unit 8 and determines the higher input voltage (hereinafter, “high”). Level) is prioritized (selected) for output.

The abnormality detecting means 11 monitors the voltage input from the first output voltage detecting means 7 and the voltage input from the second output voltage detecting means 8, and detects any one of these input voltages. When the voltage exceeds a predetermined value, it is determined that the high voltage output voltage V1 or V2 of the high voltage generating means 1 or 2 has abnormally increased, and a high voltage off signal for forcibly stopping the operation of the pulse width control means 3 is output. Output.

The operation of the circuit will be described below.

First, the high-voltage output voltage V1 of the high-voltage generation means 1
The operation in the case where is reduced will be described. The pulse width control in the normal state is performed by the stable high voltage generation means 1 of the high voltage load L1.
Is performed by detecting the output voltage V1. High-level priority means 1
“0” determines the level of the output voltage of the output voltage detecting means 7 and the level of the output voltage of the output voltage detecting means 8. When the output voltage of the output voltage detecting means 7 becomes lower than the output voltage of the output voltage detecting means 8 due to a circuit or load fluctuation,
The high-level priority means 10 causes the pulse width control means 3 to generate input waveforms for the driving means 5 and the driving means 6 based on the detection result of the output voltage V2 of the high voltage generating means 2. Thus, it is possible to avoid a high voltage control state in which the output voltage V1 of the high voltage generating means 1 and the output voltage V2 of the high voltage generating means 2 are significantly reduced.

The high-voltage output voltage V1 of the high-voltage generation means 1
Is abnormal, the abnormality detecting means 11 detects an abnormal state and outputs a high-voltage off signal to the pulse width control means 3 so as to forcibly stop the input of the driving means 5 and 6.

The high voltage output voltage V2 of the second high voltage generator 2
The same applies to the case where the value has decreased or the value has abnormally increased.

As described above, the output of the first high voltage generating means 1 is detected by the first output voltage detecting means 7, and the output of the second high voltage generating means 2 is detected by the second output detecting means 8. The respective outputs are input to the pulse width control means 3 via the high-level priority means 10 to select the output of the detection means in which the detection voltage has not decreased, and the first drive means 5 and the second
Of the driving means 6 is controlled. Further, the outputs of the output voltage detecting means 7 and the output voltage detecting means 8 are detected by the abnormality detecting means 1.
When the high-voltage output voltage exceeds a predetermined voltage, the high-voltage off signal is output, and the operation of the pulse width control means 3 is forcibly stopped.

In the above embodiment, the case where the output voltage is detected as the output amount of the first and second transformer means T1 and T2 has been described. However, the present invention is not limited to this, and the output current is detected. You may do it.

Further, the high-voltage power supply includes a first high-voltage generating means 1 having a pulse width control means 3 as the high-voltage generating means.
And one second high voltage generation means 2 controlled by the pulse width control means 3 has been described. However, the present invention is not limited to this, and the first high voltage generation means and a plurality of second high voltage generation means 2 are provided. Of course, a generating means may be provided.

[0023]

As described above, according to the present invention,
In a configuration in which a plurality of high-voltage outputs are controlled by one pulse width control signal, if the high-voltage output of the high-voltage generation means used as a standard drops abnormally, the output is detected based on the detection of the output of another high-voltage generation means. By switching to generate the pulse width control signal, it is possible to return to a predetermined high voltage output without significantly lowering the high voltage output. Also,
Since a plurality of high-voltage outputs are detected at the same time, it is possible to stop the high-voltage output if any of the high-voltage outputs rises abnormally. Accordingly, it is possible to provide a high-voltage power supply device that determines an abnormally low output or an abnormal operation state and sets the output of another high-voltage generating unit to a predetermined high-voltage output.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a high-voltage power supply device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional high-voltage power supply device.

FIG. 3 is an operation explanatory diagram of the high-voltage power supply device shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st high voltage generation means 2 2nd high voltage generation means 3 Pulse width control means 5, 6 Driving means 7, 8 Output voltage detection means 10 High level priority means 11 Abnormality detection means T1 First transformer means T2 Second Transformer means L1, L2 High voltage load B1, B2 Direct current (DC) power supply Tr1, Tr2 Switching element D1, D2 Diode C1, C2 Capacitor R1-R6 Resistance

Claims (2)

[Claims] A first transformer for generating a first high voltage; and a first transformer for detecting an output of the first transformer.
Detecting means, and a first driving means for driving the first transformer means.
And a pulse width control means for controlling the first drive means based on the output of the first detection means to control the output of the first transformer means. A second transformer for generating a second high voltage; and a second drive driven by the pulse width controller to drive the second transformer and control an output of the second transformer. A high-voltage power supply device comprising: a second high-voltage generation unit having a first detection unit; a second detection unit provided in the second high-voltage generation unit for detecting an output of the second transformer unit; The pulse generator is provided between a detecting means, a second detecting means, and a pulse width control means, and detects an abnormality of the first and second high-pressure generating means based on an output of the first and second detecting means, and Abnormality that stops the operation of the width control means Detecting means, provided between the first detecting means, the second detecting means, and the pulse width controlling means, and when the output of one of the first and second high voltage generating means decreases, the first Or high-level priority means for selecting an output from a detection means that has detected a high level among the second detection means and inputting the output to the pulse width control means to control the first and second driving means. A high-voltage power supply device characterized by the following. 2. The high-voltage power supply device according to claim 1, further comprising a first high-voltage generating unit and at least one or more second high-voltage generating units.