JP3486601B2 - High voltage power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a copying machine utilizing an electrophotographic method, it relates to a high-voltage power supplies used in an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art Conventionally, a copying machine using an electrophotographic system,
In a printer or the like, a primary bias circuit of a contact charging system for charging a developing bias circuit of a jumping developing system which is a one-component developing system or an electrode to a photosensitive drum
It is usually composed of an alternating current step-up transformer and a DC-DC inverter, and is 500 at a frequency of 200 Hz to 2 KHz.
0 to 6 for alternating current with an amplitude of Vp-p to 2KVp-p
A bias in which a DC voltage of 00V is superimposed is used. In addition, recently, a circuit in which a PWM waveform is periodically changed to drive a high-frequency transformer and a DC high voltage is superimposed on a high-voltage AC waveform obtained by this is also used.

FIG . 7 is a diagram showing a schematic construction of a general copying machine having the above-mentioned high-voltage power supply device. 3 in the figure
Reference numeral 1 denotes a photosensitive drum on the surface of which a photosensitive film that reacts to light to generate an electrostatic latent image is formed, and the inside is shielded to the ground level. 32 is a surface of the photosensitive drum 31 that has a uniform electrostatic state before receiving light. A primary charger for initializing, 33 is a high voltage power source for applying a DC step-down voltage to the primary charger 32, 34 is a developing unit for forming a toner image by flying toner to the photosensitive drum 31 bearing an electrostatic latent image by receiving light, and 35 is A DC high-voltage power source for development that applies a high voltage to the developing device 34 to fly the toner to the photosensitive drum 31, and 36 causes the toner that has left the developing device 34 to float between the photosensitive drum 31 and the developing device 34, so that AC high-voltage power supply for development, which improves the reproducibility of latent image development
37 is a post charger for facilitating transfer of the toner image formed on the photosensitive drum 31 to a transfer sheet, 38 is a post DC high voltage power source for applying DC high voltage to the post charger 37,
39 is an AC high-voltage power supply for the post that applies an AC high voltage to the post charger 37, 40 is a transfer charger that transfers the toner image on the photosensitive drum 31 to a transfer sheet, and 41 is D to the transfer charger 40.
C DC high-voltage power source for transfer that applies high voltage, 42 is a separation charger that separates the transfer paper in contact with the photosensitive drum 31 from the photosensitive drum 31 without disturbing the transferred image, 43 is a high voltage DC that is applied to the separation charger 42 Separation DC high voltage power supply, 44 is a separation AC high voltage power supply for applying AC high voltage to the separation charger 42, 45 is a pre-cleaner charger that facilitates removal of residual toner remaining on the photosensitive drum 31 after transfer, and 46 is a cleaner Cleaner D for applying high DC voltage to the pre-charger 45
A C high-voltage power supply, 47 is a pre-cleaner AC high-voltage power supply that applies AC high voltage to the pre-cleaner charger 45, and 48 is a cleaner that scrapes off the residual toner adhering to the photosensitive drum 31.

In the copying machine as described above, the developing device 34 is usually used.
Since the AC + DC type high voltage is used for the developing bias applied to the developing roller, the developing reproducibility of the electrostatic latent image is excellent and the halftone reproduction is also excellent, but on the other hand, the ground shield of the photosensitive drum 31 and the developing device 34 are A slight potential fluctuation during the period may appear as unevenness in a halftone image. This unevenness changes in its density depending on the magnitude of the potential fluctuation, and when the potential fluctuation has a periodicity, it becomes a stripe-shaped unevenness that changes depending on the rotation speed of the photosensitive drum 31 and the cycle of the potential fluctuation. appear. Since the streak-like unevenness changes the interval of the streaks depending on the correlation between the rotation speed of the photosensitive drum 31 and the cycle of the potential fluctuation, the interval is changed when the rotation speed of the photosensitive drum 31 is slow or the cycle of the potential fluctuation is short. The streaks are short, and the streaks are long when the rotation speed is high or when the potential fluctuation cycle is long. Therefore, as the AC high voltage of the developing bias, a high frequency of about 1.5 to 2.5 KHz is usually used. In fact, the fluctuation of the potential is too fast at this frequency, and no visible streak appears.

However, it is difficult to fix the inner shield of the photosensitive drum 31 to the ground because the photosensitive drum 31 is a rotating system, and it is difficult to manage the contact resistance although the structure is mechanically in contact with the ground. Therefore, as shown in FIG. 7, when a contact resistance appears between the drum shield and the ground, the post charger 37 and the separation charger 4 can be used.
2, and A applied to the pre-cleaner charger 45
The C high voltage signal causes the voltage of the drum shield to fluctuate, which causes the potential between the drum shield and the developing device 34 to fluctuate. Normally, the AC high voltage of these post, separation, cleaner pre-charger 37, 42, 45 is 500
Although it has a frequency of about 1500 Hz, due to temperature temperature characteristics of the frequency and variations in the frequency of the oscillator, interference between this frequency and the developing bias frequency occurs, resulting in a low-frequency (about 200 Hz or less) beat frequency. Streaks occur in the copied image.

In addition, downsizing of copying machines and printers in recent years,
With the increase in the number of optional devices due to cost reduction and higher functionality, there is a tendency to unify the power supply for operation of the high voltage power supply, which was conventionally divided into the control system and the power system, only to the power supply for the control system. In this case, the ripple of the power supply line generated by the switching drive for obtaining the high voltage may vibrate the high voltage control output. For example, DC of development bias
When this vibration occurs, the vibration interferes with the AC of the developing bias, and the beat frequency causes streaking in the copied image. Normally, a push-pull drive circuit including a transformer T2 as shown in FIG. 8 is used for the AC high voltage of the post, separation, and pre-cleaner chargers 37, 42, and 45. The ripple at the time is twice as high as the output high voltage AC (1000 ~
(3000 Hz), which is generated in the power supply line, vibrates the developing bias DC, and interferes with the developing bias AC. At this time, when the vibration frequency of the developing bias AC and the vibration frequency of the developing bias DC due to the power supply ripple cause a low-frequency beat of about 200 Hz or less, visible streaking occurs on the copied image. For this reason, the frequency of the AC high voltage for the separation, post and cleaner pre-charger is set so that twice the frequency is separated from the frequency of the developing bias AC high voltage to the extent that low frequency beat does not occur. Also in this case, the above frequencies may be close to each other due to variations in the oscillation circuit and temperature characteristics, and streaking may occur.

Furthermore, in recent years, for the purpose of downsizing and cost reduction of the developing bias AC transformer, a high-frequency small transformer is used, and its output is periodically charged / discharged to / from a capacitor for 1.5 to 2. A developing bias circuit that obtains an AC output of about 5 KHz has also been put into practical use, but in this type of circuit, the high-voltage output of high-frequency switching is modulated to a low frequency, so a high-frequency ripple (10 to 10) is added to the low-frequency output. 30V) is on board. Therefore, the high frequency ripple and the ripple (10 to 30 V) accompanying the switching of the DC output of the developing bias generate a beat, and a streak-like unevenness may appear in the image.

[0008]

THE INVENTION Problems to be Solved by the conventional high-voltage power supply device than being configured as described above, may beat a low frequency is generated by interference between the current image bias exchanges and other high voltage AC, In this case, there is a problem that streaky unevenness appears in the image.

The present invention has been made by paying attention to the above-mentioned problems, and it is possible to properly control the output of high voltage and prevent the streaking of images in a copying machine or the like. and its object is to provide a high voltage power supply.

[0010]

Means for Solving the Problems] high-voltage power supply equipment of the present invention
Is configured as follows.

(1) Development bias for developing a toner image
As a first high voltage output that superimposes AC on DC
However, the AC component must be included in at least one of the other electrophotographic processes.
An electrophotographic method for forming an image using the second high-voltage output
A high-voltage power supply device used in the image forming apparatus of
The AC component of the first high-voltage output and the intersection of the second high-voltage output
The frequency of the beat of the interference wave due to the flow component is
Frequency range that causes streaking in the formed image
Set the frequency of each AC component so that
It depends on the variation of the oscillation circuit and the temperature characteristics.
The frequency fluctuation of each AC component causes the beat of the interference wave.
To prevent the frequency of
Source oscillation of each AC component is generated by a common oscillator output .

(2) In the apparatus of (1) above, the drying
The wave is composed of the AC component of the first high voltage output and the second high voltage output.
The AC component of the pressure output is generated via each electrophotographic load.
I made it so that it could be punished .

(3) In the device of ( 1 ) above, the drying
The wave is driven by the first high voltage output and the second high voltage output.
It was made to be able to be generated through the dynamic power source .

(4) First driven by switching at high frequency
1 step-up transformer and the output of the step-up transformer is rectified
A diode and a capacitor for charging the rectified boosted output.
And the voltage charged in the capacitor periodically discharged
And a driving means for driving the step-up transformer.
The discharge operation by the discharge means is alternately operated at a low frequency.
AC bias is generated by
A second step-up transformer that is switching-driven, and the second step-up transformer
And a diode that smoothes the output from the step-up transformer.
And a smoothing circuit having a capacitor,
DC output is smoothed by the smoothing means
To generate the DC bias and the AC bias to the generated DC bias
It is configured to supply the bias output with superimposed
A high-voltage power supply device used in an electrophotographic device,
The drive frequency of the first step-up transformer that generates the AC bias.
Second step-up transformer for generating the wave number and the DC bias
The frequency of the beat of the interference wave due to the driving frequency of
Frequency that causes streaking in the formed image in the photographic process
The frequency of each AC component should be
In addition to setting the
Therefore, the frequency fluctuations of the respective AC components cause the interference wave
Prevent the beat frequency from reaching the frequency range
The source oscillation of each AC component is generated by a common oscillator output.
Used in an image forming apparatus characterized by being configured
It was as to be.

(5) In the apparatus of (4) above, the drying
The wave is a superposition of the AC bias and the DC bias.
Contracts characterized by being caused by
The image forming apparatus according to claim 4 is used .

(6 ) In the apparatus of (4) above, the drying
The wave is a first step-up transformer that produces the AC bias.
And a second step-up transistor for generating the DC bias.
The drive power supply that is commonly used for
The method according to claim 4, characterized in that it is squeezed.
It was adapted for use in the described image forming apparatus .

[0017]

[0018]

[0019]

[0020]

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention. This embodiment is applied to a copying machine provided with a plurality of AC voltage generating circuits that output AC high voltage.

In FIG. 1, 11 is an AC for developing bias.
Oscillation circuit that generates a signal with an oscillation frequency that is an even multiple (2 times, 4 times, 6 times, ...) Of the least common multiple of the frequency, separation, and the AC frequency for post, and 12 is the number of repetitions of the signal from the oscillation circuit 11. And a counter circuit that inverts the output when it reaches a predetermined count number, 13 counts the number of times the signal from the oscillation circuit 11 is repeated, and inverts the output when the predetermined count number is reached Opposite phase 2
A counter circuit having an output, a developing bias AC generating circuit (AC voltage generating circuit) for driving a high voltage transformer (not shown) on the basis of an inverted repetitive signal from the counter circuit 12 to generate the AC high voltage for the developing bias, 15 Push-pull-drives the high-voltage transformer based on two inverted repetitive signals from the counter circuit 13, and separates and posts AC.
It is a separation post AC high voltage generation circuit (AC voltage generation circuit) that generates high voltage.

In the above circuit, the developing bias AC is separated from the developing bias AC by the oscillator circuit 11, and the post AC high voltage is synchronized. In this case, separation AC and post A
C shares a single drive circuit and is generated by setting the output windings of the high-voltage transformer to two outputs. Therefore, the separation AC and the post AC are synchronized and have the same frequency output. There is. Further, the frequency of each high-voltage AC output is described as an example in which the developing bias AC is 1800 Hz and the separating / posting AC is 1500 Hz. In this case, the contact resistance between the shield of the photosensitive drum and the ground (see FIG. 7) . ) Causes streaking. That is, in a normal state, since the frequency difference between the two outputs is relatively high at 300 Hz, no visible streak appears, but due to variations in one or both output frequencies and temperature characteristics, When the output frequencies are close to each other, a beat due to the output frequencies of both causes the potential between the photosensitive drum shield and the developing device to oscillate at a low frequency, and the invisible streak occurs in the copied image as described above.

However, in the present embodiment, since the outputs of the high voltage generating circuits 14 and 15 are synchronized as described above, the high voltage output can be properly controlled, and streaks appearing in the image. It is possible to prevent unevenness.

FIG. 2 shows the counter 12, which serves as a frequency dividing circuit,
It is a block diagram which shows the detailed structure of 13. In the figure, 16 is a down counter that uses a signal from the oscillation circuit 11 as a clock input, 17 is a data input circuit that inputs data corresponding to a half cycle of a desired drive waveform to the down counter 16, and 1
Reference numeral 8 is a 0 output detection circuit which detects that the output of the down counter 16 has become "0" and outputs a signal, and 19 is a flip-flop circuit which receives the signal from the 0 output detection circuit 18 and inverts the output level. , Has two opposite logic level outputs. The counter circuit 12 is a circuit using only one output of the two outputs of the flip-flop circuit 19 in FIG.

In the circuit of FIG. 2, the down counter 16
Uses the signal from the oscillation circuit 11 as a clock to count down the data input from the data input circuit 17. The counted-down output data is input to the 0-output detection circuit 18, and the 0-output detection circuit 18 outputs a pulsed signal when the counter output becomes "0". The flip-flop circuit 19 receives the pulse-shaped trigger signal and inverts two opposite logic level outputs. Further, the 0 output detection circuit 18 enables the data input of the down counter 16 by the trigger signal, and the down counter 16 outputs the data input from the data input circuit 17 in response to the rising of the clock. set. By the above operation, the counter circuits 12 and 13 invert the output for each predetermined counter value, and generate the drive timing signal for the high-voltage AC generation circuits 14 and 15 in FIG.

Next, a method of setting the oscillation frequency of the oscillation circuit 11 and the input data of the data input circuit 17 will be described. In the present embodiment, the desired high-voltage AC output frequency is 1800 Hz for the developing bias AC and 1500 Hz for the separating / posting AC. In order to generate these frequencies by the countdown of the clocks, the clocks need to be frequencies that are even multiples of the least common multiple of both. The reason why it is set to an even multiple is that only one half cycle of the desired output can be obtained in one operation from the data set until the counter value becomes “0”. As an example, if the oscillation frequency of the oscillation circuit 11 is 18 KHz, half cycle counter value data may be set to "5" to generate the developing bias AC of 1800 Hz. As a result, a half cycle of the high-voltage AC that outputs 5 times the cycle of 18 KHz is output, and the frequency is 1/10
It becomes 0 Hz. Similarly, if the data value on the separation / posting AC side is "6", the frequency of the output high-voltage AC is 1/12 of the clock, and the oscillation frequency of the oscillation circuit 11 is 18 KHz. A high voltage output of is obtained.

As described above, the driving frequency of the AC high voltage for developing bias and the AC high voltage for separating and post is set to the single oscillation circuit 1.
Since the frequency is determined by dividing the frequency by 1, the frequencies do not approach each other due to variations in the oscillation circuit 11 and temperature characteristics. If the frequency difference between the two is widened by design, AC for development bias and separation for post and Low-frequency beats due to interference with AC can be suppressed, and the streak appearing in an image can be prevented as described above.

Second Embodiment FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention. In the embodiment of FIG. 2 described above, the case where the developing bias AC is a rectangular wave having a duty of 50% has been described as an example. However, in this embodiment, by providing a data switching means, outputs other than the above duty can be obtained. You can get it.

That is, in the circuit of FIG. 3, the output side of the 0 output detection circuit 18 is connected to the data input circuit 17 together with the down counter 16 and the flip-flop circuit 19. The data input circuit 17 is configured to switch between two types of data each time a signal is input from the 0 output detection circuit 18, whereby the output of the flip-flop circuit 19 is H (high). Signals having different output periods of the level output and the L (low) level output are generated.

FIG. 4 shows an example of the data input circuit 17 which serves as duty setting means in this case. The figure shows an example in which the H level and L level cycles are set to 7 to 3 (duty 30%). The counter value for H level output is set to "7" and the counter value for L level output is set to "3". To do. The counter value “7” is represented by a 4-bit binary expression “0111” and the counter value “3” is represented by “0011”. Therefore, the third bit is set every time the 0 output detection circuit 18 receives the pulse signal. Just flip it over. The data input circuit 17 shown in FIG. 4 has a T-flip-flop circuit 20 for realizing the above operation.
Receives the output of the 0 output detection circuit 18, and uses the output signal of the flip-flop circuit 20 as the third bit data.

In the circuit having the above structure, when the oscillation frequency of the oscillation circuit 11 is 18 KHz, the H level is about 389 u.
An AC output for the developing bias whose S and L levels are about 167 uS is obtained, and its duty is 30% as desired.

As described above, the data input circuit 17 for inputting data to the down counter 16 is provided with the 0 output detection circuit 18
By providing the data switching means for switching between two types of input data each time the detection signal is detected, it is possible to variously change the desired output AC high voltage.

[Third Embodiment] FIG. 5 is a block diagram showing the configuration of a third embodiment of the present invention. In the above-described first and second embodiments, an example in which the developing bias AC high voltage and the other AC high voltage are synchronized has been described for the developing bias AC and the separation and post AC. Here, in the method of obtaining the AC for the developing bias by frequency-modulating the output signal from the high frequency transformer, switching of the DC for the developing bias to be superimposed on the AC for the developing bias and the AC for the developing bias.
The case of controlling in synchronization with the drive switching of the high frequency transformer that generates

FIG. 5 shows a block diagram of the circuit in this case. In the figure, 21 is an oscillating circuit that generates a synchronization signal for the switching timing of the developing bias AC and the developing bias DC, and 22 is a high frequency transformer that is driven to switch based on the signal from the oscillating circuit 21 to output AC high voltage. The high-voltage AC generation circuit constitutes an AC voltage generation circuit that outputs an AC high voltage of a desired frequency together with a capacitor C11 that charges and discharges the high-voltage output from the high-voltage AC generation circuit 22. Reference numeral 23 is an output terminal thereof, 24 is a frequency dividing circuit for dividing the synchronizing signal from the oscillation circuit 21 to generate a predetermined frequency signal for developing bias, and 25 is a desired duty based on the output signal from the frequency dividing circuit 24. A duty signal generating circuit for generating a signal, 26 is a duty signal generating circuit 25
Based on the duty signal from
A discharging circuit for discharging the high voltage charged in the circuit 27, a DC circuit 27 for rectifying the AC voltage generated by switching-driving the transformer based on the synchronization signal from the oscillation circuit 21.
High voltage DC generator circuit that outputs high voltage (DC voltage generator circuit)
Is.

Next, in the circuit operation of FIG. 5, the developing bias frequency is 1800 Hz and the frequency dividing ratio of the frequency dividing circuit 24 is 1/32.
The case will be described as an example.

If the oscillation frequency of the oscillation circuit 21 is set to 57.6 KHz (1800 × 32) from the developing bias frequency condition and the frequency division ratio of the frequency division circuit 24 given in the above example, the high voltage AC generation circuit is generated by this frequency. 22 and high voltage DC
Since the generating circuit 27 is driven, a ripple of 57.6 KHz is generated at the output of each of these circuits. The output ripples of both are combined at the output end 23,
Both ripples are synchronized by sharing the oscillation circuit 21, and the high frequency ripples of both are unified, so that low frequency beat output is not generated. Therefore, it is possible to suppress the generation of streak appearing in the image.

On the other hand, the frequency divider circuit 24 divides the output frequency of the oscillator circuit 21 by 32 and generates a signal of 1800 Hz at its output. The duty signal generating circuit 25 receives the 1800 Hz signal from the frequency dividing circuit 24 and generates a duty signal to operate the discharge circuit 26 at a desired duty. The discharge circuit 26 discharges the high voltage charged in the capacitor C11 by performing a discharging operation for a predetermined period by the duty signal.

By repeating the above, 5
A high voltage output having a small ripple of 7.6 KHz and modulated at 1800 Hz appears, and 5 V from the high voltage DC generating circuit 27 appears.
Combined with DC high voltage with small ripple of 7.6 KHz. Then, the combined high voltage is supplied to the load.

FIG. 6 shows the duty signal generating circuit 25.
An example is shown. In the figure, 28 is an integrating circuit that integrates the signal from the frequency dividing circuit 24 and outputs a triangular wave signal, and 29 is the triangular wave signal output from the integrating circuit 28 and a reference voltage source 30 in advance.
Is compared with the reference level (Vrep) set by
It is a comparator circuit that generates an L signal. The above-mentioned discharge circuit 26 controls the discharge operation by the signals of H and L, whereby a high voltage output with a desired duty can be obtained.

[0041]

As described above, according to the present invention, since the respective high voltage outputs are controlled in synchronization with each other, the high voltage output can be appropriately controlled, and the streak of the image can be prevented. The effect is that it can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of the counter circuit of FIG.

FIG. 3 is a block diagram showing a configuration of a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing an example of the data input circuit of FIG.

FIG. 5 is a block diagram showing the configuration of a third embodiment of the present invention.

FIG. 6 is a block diagram showing an example of the duty signal generation circuit of FIG.

FIG. 7 is a schematic configuration diagram of a general copying machine.

FIG. 8 is a circuit diagram showing an example of a push-pull drive circuit.

[Explanation of symbols]

11 oscillator circuit 14 Development bias AC generation circuit 15 Separation Post AC High Voltage Generation Circuit 17 Data input circuit (duty setting means) 21 Oscillation circuit 22 High voltage AC generation circuit 24 frequency divider 27 High voltage DC generator T1 transformer

Claims (6)

(57) [Claims] 1. A developing bias for developing a toner image
While using the first high-voltage output that superimposes alternating current on direct current,
At least one of the other electrophotographic processes including an AC component
An electrophotographic image forming image using the high voltage output of 2
A high-voltage power supply device used in an image forming apparatus, comprising:
The AC component of the first high-voltage output and the AC component of the second high-voltage output
The beat frequency of the interference wave due to
In the frequency domain that causes streaking in the formed image.
If you set the frequency of each AC component so that
In both cases, the above-mentioned
The frequency fluctuations of various AC components cause the beat frequency of the interference wave.
Each of the above-mentioned crossings is performed so that the wave number does not reach the frequency range.
So that the source oscillation of the flow component is generated by the common oscillator output
A high-voltage power supply device used in an image forming apparatus characterized in that 2. The interference wave is an intersection of the first high voltage output.
The flow component and the AC component of the second high-voltage output are the respective electrons.
The feature is that it can be generated through the photographic load.
A high-voltage power supply device used in the image forming apparatus according to claim 1 . 3. The interference wave is the same as the first high-voltage output and before.
It is generated via the drive power source of the second high voltage output.
The image formation according to claim 1, wherein
High-voltage power supply device used in the equipment. 4. A first drive driven by high frequency switching.
Step-up transformer and die for rectifying the output of the step-up transformer
And a capacitor for charging the rectified boost output
And periodically discharge the voltage charged in the capacitor
And a discharge means for driving the step-up transformer and
Alternating the discharge operation by the discharge means at low frequency
AC bias is generated by the
Second boosting transformer driven by a switch, and the second boosting transformer.
A diode and capacitor that smooth the output from the voltage transformer.
And a smoothing circuit having a
The output from is smoothed by the smoothing means to generate a DC bias.
And the AC bias is added to the generated DC bias.
A battery configured to feed the folded bias output to the developer.
A high-voltage power supply device used in a child photographic device,
Drive frequency of the first step-up transformer that generates a current bias
And a drive of a second step-up transformer that generates the DC bias.
The frequency of the beat of the interference wave due to the moving frequency is
Frequency domain to generate a banding to put that forms images in Step
Set the frequency of each AC component so that it does not fall in the range
In addition, due to variations in the oscillation circuit and temperature characteristics
The frequency fluctuations of the respective AC components cause the interference wave
Before the frequency does not reach the frequency range
Source oscillation of each AC component is generated by a common oscillator output.
It is used in an image forming apparatus characterized by
That the high-voltage power supply unit. 5. The interference wave is the AC bias and the
It is caused by superposition with DC bias.
The image forming apparatus according to claim 4, characterized in that
High-voltage power supply apparatus need. 6. The interference wave generates the AC bias.
Drive the first step-up transformer and generate the DC bias.
Commonly used to drive the second booster transformer
That it can be generated via the drive power supply
A high-voltage power supply device used in the image forming apparatus according to claim 4 .