JPH0916033A - High voltage power source device and image printing device - Google Patents

Abstract

PURPOSE: To surely prevent intermittent abnormal discharge causing when printing is forcedly continued, etc., in spite of that the abnormal discharge occurs in an electrifier and to obtain higher safety by forcedly stopping a high voltage transformer output when the abnormal discharge such as spark discharge, etc., occurs in the electrifier is continued. CONSTITUTION: When an overcurrent flows from a high voltage transformer part 1 through the electrifier, the number of times of the overcurrent intermittently flowing from the high voltage transformer part 1 through the electrifier are counted by a timer circuit 5a in a second overcurrent protection circuit part 5 according to the operation of a first overcurrent protection circuit part 4, and when the number of times counted by the timer circuit 5a arrive at the number of prescribed times, the intermittent high voltage output from the high voltage transformer part 1 to the electrfier is stopped, and the operation of the high voltage transformer 1 is stopped perfectly.

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 device equipped with a high-voltage transformer and an image printing apparatus such as an electrophotographic copying machine and a printer equipped with the high-voltage power supply device, and more particularly to preventing abnormal discharge from continuing. The present invention relates to a high-voltage power supply device and an image printing device which are suitable for eliminating wasteful power consumption.

[0002]

2. Description of the Related Art Conventionally, an image printing apparatus such as an electrophotographic copying machine or a printer is provided with a primary charging device for uniformly charging a photosensitive member and a transfer charging device for transferring a latent image formed on the photosensitive member onto a copy sheet. It is equipped with various high voltage corona chargers such as a container, a separation charger for separating the paper from the photoconductor, and the like. By the way, in the case where a spark discharge occurs due to some abnormality in the corona charger of the image printing apparatus described above, in order to prevent the copy paper or peripheral parts from being ignited or smoked by the spark discharge, the image The printing device is provided with a protection circuit that detects overcurrent and limits the high voltage output to the corona charger.

FIG. 9 is a circuit diagram showing a high-voltage power supply device with a protection function provided in a conventional image printing apparatus. The high-voltage power supply device includes a high-voltage transformer unit 1, a drive circuit unit 2 that drives the high-voltage transformer unit 1, and a control circuit unit 3 that controls a current supplied from the high-voltage transformer unit 1 to a charger (not shown).
And an overcurrent protection circuit section 4 for intermittently operating the high voltage transformer section 1 when an overcurrent flows to the charger.

1 of the high-voltage transformer 1a of the high-voltage transformer section 1
The secondary side is connected to the power source 1b, and the secondary side is connected to the charger. The collector side of the transistor 2a of the drive circuit unit 2 is connected to the primary side of the high voltage transformer 1a, and the base side is P
WM oscillator (PWM OSC: Pulse Width Modulation)
Oscirater) 2b. The resistor 3a and the capacitor 3b of the control circuit unit 3 are connected to the high voltage transformer 1a and also to the + input terminal of the amplifier 3c. The reference power source 3d is connected to the minus input terminal of the amplifier 3c, and the output terminal is connected to the PWM oscillator 2b. The-input terminal of the amplifier 4a of the overcurrent protection circuit unit 4 is the amplifier 3
It is connected to the + input terminal of c, and the reference power supply 4
b is connected, and the output terminal is connected to the base side of the transistor 4c. The collector side of the transistor 4c is P
It is connected to the WM oscillator 2b.

Normally, when an overcurrent flows into the charger, the overcurrent protection circuit section 4 operates to stop the driving of the high voltage transformer section 1. However, when the current value falls below a predetermined value, the high voltage transformer section 1
Drive is restarted. For example, when the wire of the charger is broken, the overcurrent protection circuit unit 4 is activated because the overcurrent flows even if the driving of the high voltage transformer unit 1 is restarted, and the output of the high voltage transformer unit 1 is stopped. The operation is intermittently repeated every several tens of msec. As a result, the power of the abnormal discharge is limited, and even if foreign matter such as copy paper is clogged at the abnormal discharge location, it is protected from ignition or smoke.

FIG. 10 is a circuit diagram showing a high-voltage generator installed in a conventional image printing apparatus or the like. The high voltage generator includes a power supply 101, a high voltage transformer 102, a rectifying / smoothing diode 103 and a capacitor 104 connected to a secondary side of the high voltage transformer 102, and a high voltage output terminal 105.
A transistor 106 connected to the primary side of the high-voltage transformer 102, a capacitor 107, a resistor 108, and an error amplifier 109 connected to the secondary side of the high-voltage transformer 102.
A reference power supply 110 connected to one input terminal of the error amplifier 109, a PWM (Pulse Width Modulation) circuit 111 connected to the output terminal of the error amplifier 109,
The hysteresis comparator 112, a reference power source 113 connected to one input terminal of the hysteresis comparator 112, and a transistor 114 connected between the PWM circuit 11 and the hysteresis comparator 112.

In the high voltage generator described above, the PWM circuit 1
Transistor 1 based on the pulse signal output from 11
Power supply 101 by switching operation of 06.
The DC voltage supplied from the converter is converted into a high voltage by the transformer 102, and the diode 103 and the capacitor 104
Thus, a high voltage output is obtained at the high voltage output terminal 105. The high voltage output of the high voltage output terminal 105 is detected by the output detection circuit including the resistor 108 and the capacitor 109, and the error amplifier 1
09 and the reference power supply 110, an error output corresponding to the detection value of the output detection circuit is input to the PWM circuit 111,
In order to obtain the set high voltage output, the PWM circuit 11
An on / off / pulse width of 1 is determined.

On the other hand, since the output of the hysteresis comparator 112 becomes "High level" when the detection value of the output detection circuit exceeds the potential of the reference power source 113, the transistor 114 is turned on. In this case, the hysteresis comparator 112 holds "High level" until the detection value of the output detection circuit reaches a predetermined set potential lower than the potential of the reference power supply 113. In this way, every time a load abnormality of the high voltage output of the high voltage output terminal 105 occurs, the protection circuit including the hysteresis comparator 112 and the transistor 114 operates. FIG. 11 shows such a state. Reference A shows the time change of the detection value (load current) of the output detection circuit, reference B shows the change of the output of the hysteresis comparator 112 with time, and reference C shows the PWM circuit. The operation (“High level”) and stop (“Low level”) of the output of 111 are shown. Point a in FIG. 11
When a load abnormality occurs in A, B and C described above, the state shown in the figure is exhibited, and the high voltage output of the high voltage output terminal 105 becomes an intermittent output rather than a steady output.

[0009]

However, in the conventional high-voltage power supply device shown in FIG. 9, the operator forcibly prints despite the abnormal discharge occurring in the corona charger of the image printing device. If the above procedure was continued, the spark discharge would intermittently continue, which was a safety issue.

Further, in the conventional high-voltage generator shown in FIG. 10, as long as the load abnormality continues, the high-voltage output due to the load abnormality occurrence continues to be generated intermittently and with the output decreasing. This assumes that the load will recover from an abnormal condition to a normal condition.However, because the abnormal condition of the load cannot be recovered, the high-voltage output is continuously supplied intermittently, which means the high-voltage generator. Not only that, but there was the problem of wasted power consumption.

A first object of the present invention is to forcibly stop the output of the high voltage transformer when a state in which an abnormal discharge such as a spark discharge is generated in the charger continues, so that the image printing apparatus Even if the operator is abnormally discharging the charger, it is possible to reliably prevent the intermittent abnormal discharge that occurs when printing is forcibly continued for a long time. An object of the present invention is to provide a high-voltage power supply device and an image printing device that can achieve safety. A second object of the present invention is to provide a high voltage power supply device capable of eliminating wasteful power consumption by stopping the output of the high voltage transformer when the load abnormality continues for a predetermined time.

[0012]

According to a first aspect of the present invention, there is provided a high voltage transformer which outputs a high voltage to a charger of an image printing apparatus, and a high voltage transformer when an overcurrent flows from the high voltage transformer to the charger. In a high-voltage power supply device comprising an overcurrent protection unit for intermittent operation, a counting unit that counts the number of times an overcurrent flows from the high-voltage transformer to the charger.
A second overcurrent protection unit is provided to stop the output of the high-voltage transformer when the number of times counted by the counting unit reaches a predetermined number.

According to a second aspect of the present invention, a high voltage transformer for outputting a high voltage to a charger of an image printing apparatus, and an overcurrent protection for intermittently operating the high voltage transformer when an overcurrent flows from the high voltage transformer to the charger. A high-voltage power supply device including: a high-voltage power supply device; and an integration unit that extracts an AC waveform of the overcurrent flowing from the high-voltage transformer to the charger and integrates the AC waveform, and an integrated value by the integration unit has a predetermined value. A second overcurrent protection unit for stopping the output of the high-voltage transformer is provided when it exceeds.

The invention of claim 3 is the same as claim 1 or 2
The high-voltage power supply device according to claim 1, further comprising: an automatic recovery circuit that restarts the output from the high-voltage transformer after a predetermined time has elapsed since the output of the high-voltage transformer was stopped due to the operation of the second overcurrent protection unit. Is taking.

According to a fourth aspect of the present invention, in an image printing apparatus such as an electrophotographic copying machine and a printer, the operation of the high voltage power source apparatus according to the first, second or third aspect and the operation of the second overcurrent protection unit. Accordingly, a configuration is provided in which a display unit that displays an abnormal state is provided.

According to a fifth aspect of the present invention, the image printing apparatus according to the fourth aspect has a function of stopping the operation of the entire apparatus when the second overcurrent protection unit operates. There is.

According to a sixth aspect of the present invention, a high-voltage transformer that outputs a high voltage, an output detection unit that detects the output of the high-voltage transformer, and an output of the high-voltage transformer are intermittent when the load is abnormal based on a value detected by the output detection unit. A high-voltage power supply device including a protection unit for outputting a second protection unit for stopping output from the high-voltage transformer when a load abnormality continues for a predetermined time.

[0018]

According to the first aspect of the present invention, the counter is provided with a counter whenever an overcurrent flows from the high-voltage transformer to the charger of the image printing apparatus.
The number of overcurrents flowing to the charger is counted. And the second
The overcurrent protection unit completely stops the output of the high voltage transformer when the number of overcurrents counted by the counting unit reaches a predetermined number. As a result, it is possible to reliably prevent the intermittent abnormal discharge that occurs when the operator of the image printing apparatus forcibly continues printing for a long time.

According to the second aspect of the invention, every time an overcurrent flows from the high voltage transformer to the charger of the image printing apparatus, the integrating section extracts the AC waveform of the overcurrent and integrates the extracted AC waveform. Then, the second overcurrent protection unit completely stops the output of the high voltage transformer when the integrated value integrated by the integrating unit exceeds a predetermined value. As a result, it is possible to reliably prevent the intermittent abnormal discharge that occurs when the operator of the image printing apparatus forcibly continues printing for a long time.

According to the third aspect of the present invention, the automatic recovery circuit is configured such that, after the output of the high-voltage transformer is stopped by the operation of the second overcurrent protection unit, the high-voltage transformer is operated at a predetermined time after the output is stopped. Restart the output from the transformer. This can eliminate the complexity of the operator of the image printing apparatus manually restarting.

According to the fourth aspect of the present invention, when the second overcurrent protection section operates, the fact that it is in an abnormal state is displayed on the display section. This allows the operator of the image printing apparatus to accurately grasp the occurrence of an abnormality.

According to the invention of claim 5, when the second overcurrent protection portion operates, the function of stopping the operation of the entire image printing apparatus operates. As a result, it is possible to prevent a problem that the operator of the image printing apparatus forcibly continues printing.

According to the invention of claim 6, when the high voltage output is generated from the high voltage transformer, the high voltage output is detected by the output detection unit. Then, when the load abnormality continues for a predetermined time, the second protection unit stops the output of the high voltage transformer.
As a result, useless power consumption can be eliminated.

[0024]

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

(1) First embodiment. FIG. 1 is a circuit diagram showing the configuration of a high-voltage power supply device equipped in the image printing apparatus according to the first embodiment. The same components as those in the first embodiment shown in FIG. 1 and the conventional example shown in FIG. 9 are designated by the same reference numerals. The high-voltage power supply device according to the first embodiment is a high-voltage transformer unit 1 that outputs high voltage to a charger (not shown) of an image printing apparatus.
A drive circuit section 2 for variably driving the high voltage transformer section 1 based on the output of the PWM oscillator 2b and the switching operation of the transistor 2a; and a control circuit for controlling a current supplied from the high voltage transformer section 1 to a charger (not shown). First, the high voltage transformer section 1 is intermittently operated based on the switching operation of the transistor 4c when an overcurrent flows to the section 3 and the charger.
The second overcurrent protection circuit section 4 and the second step of counting the number of times the overcurrent flows to the charger and stopping the driving of the high voltage transformer section 1 based on the switching operation of the transistor 5b when the number of times of counting reaches a predetermined number. It is composed of an overcurrent protection circuit section 5.

1 of the high voltage transformer 1a of the high voltage transformer section 1
The secondary side is connected to the power source 1b, and the secondary side is connected to the charger. The collector side of the transistor 2a of the drive circuit unit 2 is connected to the primary side of the high voltage transformer 1a, and the base side is P
WM oscillator (PWM OSC: Pulse Width Modulation)
Oscillater) 2b. Further, the resistor 3a and the capacitor 3b of the control circuit unit 3 are connected to the secondary side of the high voltage transformer 1a and also to the + input terminal of the amplifier 3c. By the resistor 3a and the capacitor 3b,
An overcurrent flowing from the high voltage transformer 1a to the charger is detected. The reference power source 3d is connected to the minus input terminal of the amplifier 3c, and the output terminal is connected to the PWM oscillator 2b. The amplifier 3c outputs to the PWM oscillator 2b a signal based on the input voltage difference between both input terminals.

The negative input terminal of the amplifier 4a of the first overcurrent protection circuit unit 4 is connected to the positive input terminal of the amplifier 3c, the reference power source 4b is connected to the positive input terminal, and the output terminal is on the base side of the transistor 4c. It is connected to the. Amplifier 4a
Outputs a current based on the difference in the input voltage to both input terminals to cause the transistor 4c to perform a switching operation. The collector side of the transistor 4c is the PWM oscillator 2b.
It is connected to the. The timer circuit 5a of the second overcurrent protection circuit unit 5 is connected between the resistor 3a and the capacitor 3b of the control circuit unit 3 and the base side of the transistor 5b, and the collector side of the transistor 5b is the PWM oscillator 2b.
Is connected to the output side. The timer circuit 5a causes the transistor 5b to perform a switching operation based on whether or not the number of counting the overcurrent flowing to the charger reaches a predetermined number.

Next, the operation of the first embodiment will be described. Normally, when an overcurrent flows from the high voltage transformer unit 1 to the charger, the driving of the high voltage transformer unit 1 is stopped as a result of the operation of the first overcurrent protection circuit unit 4. The high voltage output from the high voltage transformer unit 1 continues to be intermittently output to the charger unless the abnormal state is removed.

Therefore, in the first embodiment, when an overcurrent flows from the high voltage transformer unit 1 to the charger, the high voltage transformer unit 1 is intermittently switched to the charger along with the operation of the first overcurrent protection circuit unit 4. The timer circuit 5a of the second overcurrent protection circuit unit 5 counts the number of overcurrents that have flown as desired. And the second
When the number of times counted by the timer circuit 5a of the overcurrent protection circuit unit 5 reaches a predetermined number, the driving of the high voltage transformer unit 1 is stopped. As a result, intermittent high voltage output from the high voltage transformer unit 1 to the charger is stopped, and the operation of the high voltage transformer unit 1 is completely stopped.

As described above, according to the first embodiment,
The second overcurrent protection circuit 5 counts the number of times the overcurrent flows from the high-voltage transformer unit 1 to the charger and stops the driving of the high-voltage transformer unit 1 when the counted number reaches a predetermined number. When the operator of the apparatus does not notice the abnormality of the charger and forcibly continues the printing, it is possible to prevent the intermittent spark discharge from continuing, and thus to obtain higher safety.

(2) Second embodiment. FIG. 2 is a circuit diagram showing the configuration of a high-voltage power supply device equipped in the image printing apparatus of the second embodiment. The same components as those in the second and first embodiments are designated by the same reference numerals.
The high-voltage power supply device according to the second embodiment includes a high-voltage transformer unit 1 that outputs a high voltage to a charger (not shown) of an image printing apparatus, and a drive circuit unit that variably drives the high-voltage transformer unit 1 based on the output of a PWM oscillator 2b. 2 and a control circuit unit 3 that controls the current supplied from the high-voltage transformer unit 1 to a charger (not shown)
And a first overcurrent protection circuit unit 4 for intermittently operating the high voltage transformer unit 1 when an overcurrent flows to the charger, and an AC current waveform with an integrating circuit 6a when the overcurrent flows to the charger.
The second overcurrent protection circuit section 6 integrates the components and stops driving the high-voltage transformer section 1 when the integrated value exceeds a predetermined value.

1 of the high voltage transformer 1a of the high voltage transformer section 1
The secondary side is connected to the power source 1b, and the secondary side is connected to the charger. The collector side of the transistor 2a of the drive circuit unit 2 is connected to the primary side of the high voltage transformer 1a, and the base side is P
It is connected to the WM oscillator (PWM OSC) 2b.
The resistor 3a and the capacitor 3b of the control circuit unit 3 are connected to the secondary side of the high voltage transformer 1a, and the amplifier 3
It is connected to the + input terminal of c. The reference power source 3d is connected to the minus input terminal of the amplifier 3c, and the output terminal is connected to the PWM oscillator 2b.

The-input terminal of the amplifier 4a of the first overcurrent protection circuit unit 4 is connected to the + input terminal of the amplifier 3c, the reference power source 4b is connected to the + input terminal, and the output terminal is on the base side of the transistor 4c. It is connected to the. The collector side of the transistor 4c is connected to the PWM oscillator 2b. In addition, the integration circuit 6a of the second overcurrent protection circuit unit 6
Is connected between the resistor 3a and the capacitor 3b of the control circuit unit 3 and the + input terminal of the amplifier 6b, and
The reference power source 6c is connected to the input terminal. The integrating circuit 6a integrates the AC component of the current waveform when an overcurrent flows to the charger, and outputs a signal to the amplifier 6b when the integrated value exceeds a predetermined value. The output terminal of the amplifier 6b is connected to the base side of the transistor 6d, and the collector side of the transistor 6d is connected to the output side of the PWM oscillator 2b. The amplifier 6b causes the transistor 6d to perform a switching operation by outputting a current based on the input voltage difference to both input terminals.

Next, the operation of the second embodiment will be described. Normally, when an overcurrent flows from the high voltage transformer unit 1 to the charger, the driving of the high voltage transformer unit 1 is stopped as a result of the operation of the first overcurrent protection circuit unit 4. The high voltage output from the high voltage transformer unit 1 continues to be intermittently output to the charger unless the abnormal state is removed.

Therefore, in the second embodiment, when an overcurrent flows from the high voltage transformer section 1 to the charger, the high voltage transformer section 1 is intermittently transferred to the charger along with the operation of the first overcurrent protection circuit section 4. The AC component of the overcurrent current waveform
The integrating circuit 6a of the overcurrent protection circuit section 6 of FIG.
Then, when the integrated value integrated by the integrating circuit 6a of the second overcurrent protection circuit unit 6 exceeds a predetermined value, the driving of the high voltage transformer unit 1 is stopped. As a result, intermittent high voltage output from the high voltage transformer unit 1 to the charger is stopped, and the operation of the high voltage transformer unit 1 is completely stopped.

As described above, according to the second embodiment,
The second overcurrent protection circuit 6 integrates the AC component of the current waveform when an overcurrent flows from the high voltage transformer unit 1 to the charger, and drives the high voltage transformer unit 1 when the integrated value exceeds a predetermined value. Since it is stopped, it is possible to prevent the problem of intermittent spark discharge continuation, such as when the operator of the image printing device does not notice the abnormality of the charger and forcibly continues printing, thus increasing the safety. Obtainable.

(3) Third embodiment. FIG. 3 is a circuit diagram showing the configuration of a high-voltage power supply device equipped in the image printing apparatus of the third embodiment. The same components as those in the third embodiment and the first and second embodiments are designated by the same reference numerals. The high-voltage power supply device according to the third embodiment includes a high-voltage transformer unit 7 that outputs high voltage to a charger (not shown) of the image printing device.
A drive circuit unit 8 that drives the high-voltage transformer unit 7 based on a constant pulse signal output from the oscillator 8b; and a control circuit unit 3 that controls a current supplied from the high-voltage transformer unit 7 to a charger (not shown). , A first overcurrent protection circuit section 4 for intermittently operating the high voltage transformer section 7 when an overcurrent flows to the charger, and the number of times the overcurrent flows to the charger, and the number of counts reaches a predetermined number. And a second overcurrent protection circuit section 5 that stops driving the high-voltage transformer section 1 at the time.

1 of the high-voltage transformer 7a of the high-voltage transformer section 7
The secondary side is connected to the power source 7b and the emitter side of the transistor 7c, and the secondary side is connected to the charger. Further, the collector side of the transistor 8a of the drive circuit unit 8 is connected to the primary side of the high voltage transformer 7a, and the base side thereof is an oscillator (OS).
C) Connected to 8b. The resistor 3a and the capacitor 3b of the control circuit unit 3 are connected to the secondary side of the high voltage transformer 7a and also to the + input terminal of the amplifier 3c. The reference power source 3d is connected to the minus input terminal of the amplifier 3c, and the output terminal has the base side of the transistor 7c of the high-voltage transformer section 7 and the transistor 5 of the second overcurrent protection circuit 5.
It is connected to the collector side of b.

The-input terminal of the amplifier 4a of the first overcurrent protection circuit unit 4 is connected to the + input terminal of the amplifier 3c, the reference power source 4b is connected to the + input terminal, and the output terminal is on the base side of the transistor 4c. It is connected to the. The collector side of the transistor 4c is connected to the base side of the transistor 7c and the collector side of the transistor 5b. Also,
The timer circuit 5a of the second overcurrent protection circuit unit 5 includes a resistor 3a, a capacitor 3b and a transistor 5 of the control circuit unit 3.
It is connected between the base side of b and the collector side of the transistor 5a is connected to the base side of the transistor 7c.

Next, the operation of the third embodiment will be described. Normally, when an overcurrent flows from the high voltage transformer unit 7 to the charger, the driving of the high voltage transformer unit 7 is stopped as a result of the operation of the first overcurrent protection circuit unit 4. The high voltage output from the high voltage transformer section 7 continues to be intermittently output to the charger unless the abnormal state is removed.

Therefore, in the third embodiment, when an overcurrent flows from the high voltage transformer section 7 to the charger, the high voltage transformer section 7 is intermittently transferred to the charger along with the operation of the first overcurrent protection circuit section 4. The timer circuit 5a of the second overcurrent protection circuit unit 5 counts the number of overcurrents that have flown as desired. And the second
When the number of times counted by the timer circuit 5a of the overcurrent protection circuit unit 5 reaches a predetermined number, the driving of the high voltage transformer unit 7 is stopped. As a result, intermittent high-voltage output from the high-voltage transformer unit 7 to the charger is stopped, and the operation of the high-voltage transformer unit 7 is completely stopped.

As described above, according to the third embodiment,
The second overcurrent protection circuit 5 counts the number of times the overcurrent flows from the high voltage transformer unit 1 to the charger and stops the driving of the high voltage transformer unit 7 when the count number reaches a predetermined number. When the operator of the apparatus does not notice the abnormality of the charger and forcibly continues the printing, it is possible to prevent a problem in which the spark discharge is intermittently maintained, and thus higher safety can be obtained.

(4) Fourth embodiment. FIG. 4 is a circuit diagram showing the configuration of a high-voltage power supply device equipped in the image printing apparatus of the fourth embodiment. The same components as those in the fourth embodiment and the first, second and third embodiments are designated by the same reference numerals. The high-voltage power supply device of the fourth embodiment drives a high-voltage transformer unit 7 that outputs a high voltage to a charger (not shown) of an image printing apparatus, and the high-voltage transformer unit 7 based on a constant pulse signal output from an oscillator 8b. A drive circuit section 8, a control circuit section 3 for controlling a current supplied from a high voltage transformer section 7 to a charger (not shown), and an intermittent operation of the high voltage transformer section 7 when an overcurrent flows to the charger. 1 of the current waveform when the overcurrent flows into the overcurrent protection circuit unit 4 of No. 1 and the charger.
The second overcurrent protection circuit section 6 integrates the C component and stops driving the high voltage transformer section 7 when the integrated value exceeds a predetermined value.

1 of the high-voltage transformer 7a of the high-voltage transformer section 7
The secondary side is connected to the power source 7b and the emitter side of the transistor 7c, and the secondary side is connected to the charger. Further, the collector side of the transistor 8a of the drive circuit unit 8 is connected to the primary side of the high voltage transformer 7a, and the base side thereof is an oscillator (OS).
C) Connected to 8b. The resistor 3a and the capacitor 3b of the control circuit unit 3 are connected to the secondary side of the high voltage transformer 7a and also to the + input terminal of the amplifier 3c. The reference power source 3d is connected to the minus input terminal of the amplifier 3c, and the output terminal has the base side of the transistor 7c of the high-voltage transformer section 7 and the transistor 5 of the second overcurrent protection circuit 5.
It is connected to the collector side of b.

The-input terminal of the amplifier 4a of the first overcurrent protection circuit section 4 is connected to the + input terminal of the amplifier 3c, the reference power source 4b is connected to the + input terminal, and the output terminal is on the base side of the transistor 4c. It is connected to the. The collector side of the transistor 4c is connected to the base side of the transistor 7c and the collector side of the transistor 5b. Also,
The integrating circuit 6a of the second overcurrent protection circuit unit 6 is connected between the resistor 3a and the capacitor 3b of the control circuit unit 3 and the + input terminal of the amplifier 6b, and the reference power source 6c is connected to the-input terminal of the amplifier 6b. Are connected. The output terminal of the amplifier 6b is connected to the base side of the transistor 6d, and the collector side of the transistor 6d is connected to the base side of the transistor 7b.

Next, the operation of the fourth embodiment will be described. Normally, when an overcurrent flows from the high voltage transformer unit 7 to the charger, the driving of the high voltage transformer unit 7 is stopped as a result of the operation of the first overcurrent protection circuit unit 4. The high voltage output from the high voltage transformer section 7 continues to be intermittently output to the charger unless the abnormal state is removed.

Therefore, in the fourth embodiment, when an overcurrent flows from the high voltage transformer section 7 to the charger, the high voltage transformer section 7 is intermittently transferred to the charger along with the operation of the first overcurrent protection circuit section 4. The AC component of the overcurrent current waveform
The integrating circuit 6a of the overcurrent protection circuit section 6 of FIG.
Then, when the integrated value integrated by the integrating circuit 6a of the second overcurrent protection circuit unit 6 exceeds a predetermined value, the driving of the high voltage transformer unit 7 is stopped. As a result, intermittent high-voltage output from the high-voltage transformer unit 7 to the charger is stopped, and the operation of the high-voltage transformer unit 7 is completely stopped.

As described above, according to the fourth embodiment,
The second overcurrent protection circuit 6 integrates the AC component of the current waveform when the overcurrent flows from the high voltage transformer unit 7 to the charger, and drives the high voltage transformer unit 7 when the integrated value exceeds a predetermined value. Since it is stopped, it is possible to prevent the problem of intermittent spark discharge continuation, such as when the operator of the image printing device does not notice the abnormality of the charger and forcibly continues printing, thus increasing the safety. Obtainable.

In the above-mentioned first to fourth embodiments, after the output from the high voltage transformer section is stopped due to the operation of the second overcurrent protection circuit section, the high voltage An automatic recovery circuit for restarting the operation of the transformer section may be provided. This can eliminate the complexity of the operator of the image printing apparatus manually restarting the operation. Further, in the above-described first to fourth embodiments, a display unit that displays an abnormality when the second overcurrent protection circuit unit operates may be provided in the operation unit or the like of the image printing apparatus. This allows the operator of the image printing apparatus to accurately grasp the occurrence of an abnormality. Further, in the first to fourth embodiments, a function of stopping the operation of the entire device when the second overcurrent protection circuit unit operates may be provided. As a result, it is possible to prevent a problem that the operator of the image printing apparatus forcibly continues printing.

(5) Fifth embodiment. FIG. 5 is a circuit diagram showing the configuration of a high-voltage generator (high-voltage power supply device) equipped in the image printing apparatus of the fifth embodiment. The high voltage generator according to the fifth embodiment includes a power supply 11, a high voltage transformer 12, a diode 13, a capacitor 14, a high voltage output terminal 15, a transistor 16 and a capacitor 17.
, The resistor 18, the error amplifier 19, the reference power source 20,
A PWM circuit 21, a hysteresis comparator 22,
Reference power supply 23, transistor 24, diode 25
And a counter 26 and a diode 27. In the fifth embodiment, the capacitor 17 and the resistor 18
Constitutes the output detection circuit, and the hysteresis comparator 2
2 and the transistor 24 form a first protection circuit, and the counter 26 and the transistor 24 form a second protection circuit.

The power source 11 is connected to the primary side of the high-voltage transformer 12, the collector side of the transistor 16 is connected, and the diode 13, the capacitor 14, the high-voltage output terminal 15 are connected to the secondary side, and the capacitor 17 and The resistor 18 is connected. The output detection circuit is connected to one input terminal of the error amplifier 19, the reference power source 20 is connected to the other input terminal, and the output terminal is PW.
It is connected to the M circuit 21. The output of the PWM circuit 21 is connected between the transistor 24 and the transistor 16. The output detection circuit is connected to one input terminal of the hysteresis comparator 22, the reference power supply 23 is connected to the other input terminal, and the output terminal is connected to the diode 25 and the counter 26. Further, the output of the counter 26 is connected to the diode 27, and the diodes 27 and 25 are connected to the base side of the transistor 24.

Next, the operation of the fifth embodiment will be described. In the high voltage generator, the DC voltage supplied from the power supply 11 is converted into a high voltage by the high voltage transformer 12 by switching the transistor 16 based on the pulse signal output from the PWM circuit 21, and the diode 1
A high voltage output is obtained at the high voltage output terminal 15 by the capacitor 3 and the capacitor 14. The high voltage output of the high voltage output terminal 15 is detected by an output detection circuit including a capacitor 17 and a resistor 18,
The error amplifier 19 and the reference power supply 20 input an error output corresponding to the detection value of the output detection circuit to the PWM circuit 21 to turn on / off / pulse width of the PWM circuit 21 so that a set high voltage output is obtained. Is determined.

On the other hand, the output of the hysteresis comparator 22 becomes "High level" when the detection value of the output detection circuit exceeds the potential of the reference power source 23, so that the transistor 2
4 is turned on. In this case, the hysteresis comparator 22 determines that the detection value of the output detection circuit is the reference power source 23.
It keeps "High level" until it reaches a predetermined set potential lower than the potential of. Furthermore, the hysteresis comparator 22
When the output of the counter reaches the "High level" a predetermined number of times within a fixed time, the output of the counter 26 holds the "High level", so that the transistor 24 is turned on through the diode 27 and the transistor 26 is cut off. .

As described above, every time a load abnormality of the high voltage output of the high voltage output terminal 15 occurs, the first protection circuit including the hysteresis comparator 22 and the transistor 24 operates. Further, whether or not the load abnormality of the high voltage output of the high voltage output terminal 15 is in a continuous state is detected by the second protection circuit including the counter 26 and the transistor 24,
If the load abnormality continues, the transistor 16
Stop the switching operation of.

FIG. 6 shows such a situation. The output of the hysteresis comparator 22 becomes the "High level" a prescribed number of times within a fixed time, and the counter 26 becomes the "High level".
The case of holding is indicated by reference characters D and E. Incidentally, the code A
Indicates the time change of the detection value (load current) of the output detection circuit, and the symbol B is the time change of the output of the hysteresis comparator 22. When a load abnormality occurs at the point a in FIG. 6, the counter 26 holds the “High level” at the time when the rise of the output of the hysteresis comparator 22 is captured and counted up a prescribed number of times (3 times in this embodiment).

As a result, the transistor 24 is turned on and the transistor 16 is cut off. As a result, the high voltage output from the high voltage output terminal 15 is stopped. The reset circuit of the counter 26 depends on the system that uses the counter 26, and therefore its description is omitted. On the other hand, if the output of the hysteresis comparator 22 does not reach the "High level" the specified number of times (two times or less in this embodiment) within a fixed time, the counter 26 does not count up. Therefore, the counter 26 and the transistor 24
It is clear that the second protection circuit consisting of
Description is omitted.

As described above, according to the fifth embodiment,
When the load abnormality is detected, the recovery of the load abnormality is monitored for a certain period, and when the load abnormality is not recovered, the high voltage transformer 12
Is stopped, it is possible to eliminate useless power consumption.

(6) Sixth embodiment. FIG. 7 is a circuit diagram showing the configuration of a high-voltage generator (high-voltage power supply device) equipped in the image printing apparatus of the sixth embodiment.
The same components as those in the sixth and fifth embodiments are designated by the same reference numerals, and the description thereof will be omitted or simplified. The high voltage generator of the sixth embodiment includes a power source 11, a high voltage transformer 12,
Diode 13, capacitor 14, high voltage output terminal 1
5, transistor 16, capacitor 17, resistor 1
8, error amplifier 19, reference power supply 20, PWM circuit 21, hysteresis comparator 22, reference power supply 2
3, a transistor 24, a diode 28, a timer circuit 29, an AND gate 30, a latch 31, and a diode 32. In the sixth embodiment,
The method of controlling the high voltage output, the configuration of the output detection circuit and the first protection circuit are the same as those of the fifth embodiment, and the difference is that the second protection circuit is the timer circuit 29, the AND gate 30, and the latch 3.
It is composed of 1.

The operation of the second protection circuit will be described with reference to FIG. 8. The symbol H indicates the time change of the output of the timer circuit 29, and when the output of the hysteresis comparator 22 becomes "High level", the timer circuit. 29 is point b
Then, the output of the timer circuit 29 becomes "High level" after the elapse of the timer setting time. If the load abnormality of the high voltage output of the high voltage output terminal 15 has not recovered after the timer setting time has elapsed, at the point c at which the output of the hysteresis comparator 22 becomes "High level", as shown by the symbol I, the latch 31 The output becomes “High level”. PWM
The circuit 21 becomes "Low level" after the point c at which the output of the latch 31 becomes "High level".

As a result, the transistor 24 is turned on and the transistor 16 is cut off. As a result, the high voltage output from the high voltage output terminal 15 is stopped. On the other hand, when the load abnormality is recovered after the elapse of the timer setting time, the output of the hysteresis comparator 22 always holds "Low level", and therefore the output of the latch 31 always holds "Low level". Therefore, the timer circuit 2
It is obvious that the second protection circuit including the AND gate 30, the AND gate 30 and the latch 31 does not operate, and the description thereof will be omitted.

As described above, according to the sixth embodiment,
When the load abnormality is detected, the recovery of the load abnormality is monitored for a certain period, and when the load abnormality is not recovered, the high voltage transformer 12
Is stopped, it is possible to eliminate useless power consumption.

[0062]

As described above, according to the invention of claim 1, the high-voltage power supply device counts the number of times the overcurrent flows from the high-voltage transformer to the charger of the image printing apparatus,
A state in which an abnormal discharge such as a spark discharge has occurred in the charger because it has a second overcurrent protection unit that stops the output of the high-voltage transformer when the number of times counted by the counting unit reaches a predetermined number. If for a long time, the output of the high voltage transformer is forcibly stopped and the operator of the image printing device forcibly continues printing despite the occurrence of abnormal discharge in the charger. Thus, it is possible to reliably prevent the intermittent abnormal discharge from continuing, and thus to obtain higher safety.

According to the second aspect of the present invention, the high-voltage power supply device extracts an AC waveform of the overcurrent flowing from the high-voltage transformer to the charger and integrates the AC waveform, and the integral value by the integrating unit is a predetermined value. Since the second overcurrent protection unit for stopping the output of the high-voltage transformer is provided when the voltage exceeds the limit, the operator of the image printing apparatus causes an abnormal discharge in the charger as in the case of the first aspect of the invention. However, it is possible to reliably prevent the intermittent abnormal discharge that occurs when printing is forcibly continued, and thus to obtain higher safety. Play.

According to the invention of claim 3, the high-voltage power supply device automatically restarts the output from the high-voltage transformer after a lapse of a predetermined time after the output of the high-voltage transformer is stopped in accordance with the operation of the second overcurrent protection unit. Since the recovery circuit is provided, it is possible to eliminate the complexity of the operator of the image printing apparatus manually restarting.

According to the fourth aspect of the invention, the image printing apparatus displays that the high voltage power source apparatus of the first, second or third aspect of the invention and the second overcurrent protection unit are in an abnormal state in accordance with the operation. Since the image printing apparatus is provided with the display unit, the operator of the image printing apparatus can accurately grasp the occurrence of the abnormality.

According to the invention of claim 5, in the invention of claim 4, it has a function of stopping the operation of the entire image printing apparatus when the second overcurrent protection portion operates.
It is possible to prevent the problem that the operator of the image printing apparatus forcibly continues printing.

According to the sixth aspect of the present invention, since the second protection portion for stopping the output from the high voltage transformer is provided when the load abnormality continues for a predetermined time, the high voltage output is provided when the load abnormality occurs as in the conventional case. The phenomenon that the electric power is intermittently supplied is eliminated, and thus, it is possible to eliminate wasteful power consumption.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a high voltage power supply device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a high voltage power supply device according to a second embodiment of the present invention.

FIG. 3 is a diagram showing the configuration of a high-voltage power supply device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing the configuration of a high-voltage power supply device according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing the configuration of a high pressure generator according to a fifth embodiment of the present invention.

FIG. 6 is a timing chart for explaining the operation of the high voltage generator of the fifth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a high pressure generator according to a sixth embodiment of the present invention.

FIG. 8 is a timing chart for explaining the operation of the high voltage generator of the sixth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a configuration of a conventional high-voltage power supply device.

FIG. 10 is a circuit diagram showing a configuration of a conventional high voltage generator.

FIG. 11 is a timing chart for explaining the operation of the conventional high voltage generator.

[Explanation of symbols]

1,7 High-voltage transformer section 1a, 7a High-voltage transformer 2,8 Driving circuit section 3 Control circuit section 4 First overcurrent protection circuit section (overcurrent protection section) 5,6 Second overcurrent protection circuit section (second 5a Timer circuit (counter) 6a Integration circuit 11 Power supply (high voltage generator) 12 High voltage transformer 17 Capacitor (output detector) 18 Resistance (output detector) 22 Hysteresis comparator (protector) 24 Transistor ( Protecting part, second protecting part 26 Counter (second protecting part) 29 Timer circuit (second protecting part) 30 AND gate (second protecting part) 31 Latch (second protecting part)

Claims (6)

[Claims] 1. A high voltage transformer for outputting a high voltage to a charger of an image printing apparatus, and an overcurrent protection unit for intermittently operating the high voltage transformer when an overcurrent flows from the high voltage transformer to the charger. In the high-voltage power supply device, a counting unit that counts the number of times an overcurrent flows from the high-voltage transformer to the charger, and stops the output of the high-voltage transformer when the number of counts by the counting unit reaches a predetermined number. A high-voltage power supply device comprising: 2. A high-voltage transformer for outputting a high voltage to a charger of an image printing apparatus, and an overcurrent protection unit for intermittently operating the high-voltage transformer when an overcurrent flows from the high-voltage transformer to the charger. In the high-voltage power supply device, the AC of the overcurrent flowing from the high-voltage transformer to the charger is
An integrating unit for extracting a waveform and integrating the AC waveform, and a second overcurrent protection unit for stopping the output of the high-voltage transformer when the integrated value by the integrating unit exceeds a predetermined value are provided. Characteristic high voltage power supply. 3. The high-voltage power supply device according to claim 1, wherein the output from the high-voltage transformer is output after a predetermined time has elapsed since the output of the high-voltage transformer was stopped due to the operation of the second overcurrent protection unit. A high-voltage power supply device having an automatic recovery circuit for restarting the power supply. 4. An image printing apparatus such as an electrophotographic copying machine, a printer or the like, which is in an abnormal state due to the operation of the high voltage power supply apparatus according to claim 1, 2 or 3 and the second overcurrent protection unit. An image printing apparatus, comprising: a display unit that displays a message. 5. The image printing apparatus according to claim 4, further comprising a function of stopping the operation of the entire apparatus when the second overcurrent protection unit operates. 6. A high-voltage transformer that outputs a high voltage, an output detection unit that detects the output of the high-voltage transformer, and a protection unit that intermittently outputs the output of the high-voltage transformer when a load abnormality occurs based on a value detected by the output detection unit. A high-voltage power supply device comprising: a high-voltage power supply device including a second protection unit that stops the output of the high-voltage transformer when a load abnormality continues for a predetermined time.