JP7537106B2 - Power supply device and image forming apparatus - Google Patents

Description

The present invention relates to a power supply device and an image forming device.

Conventionally, technology is known for predicting faults caused by electrical leakage in power supply devices such as power supply units.

For example, in an environment where coolant is pouring down, input devices such as photoelectric sensors, proximity sensors, limit switches, and push button switches may experience breakdowns due to coolant entering the devices and causing electrical leakage. To predict electrical leakage failures in sensors, the signal input device first measures the value of the current flowing through the internal ground line. Next, while the output of the discrimination binarization circuit is in the OFF state, the signal input device generates information indicating the degree of leakage based on the measured current value and a preset current value. In this way, a technology is known that accurately predicts electrical leakage failures before they occur (see, for example, Patent Document 1).

However, conventional technology does not take into account abnormalities in electrical components such as harnesses that may occur due to deterioration over time. As a result, even if an abnormality occurs in an electrical component, the abnormality is not detected. As a result, accidents caused by abnormalities in electrical components may not be sufficiently prevented.

One aspect of the present invention aims to detect abnormalities in electrical components in a power supply device and an image forming device.

According to one embodiment of the present invention, a power supply device includes:
an output section that outputs an output current to a connected load;
A measurement unit that measures a current value of the output current;
a storage unit configured to store a first current value, the first current value being the current value measured in a first state;
The control circuit includes a judgment unit that compares a second current value, which is the current value measured in a second state in which time has passed since the first state, with the first current value, and judges whether the second current value has changed by a predetermined value or more with respect to the first current value.

Embodiments of the present invention can detect abnormalities in electrical components in power supplies and image forming devices.

FIG. 2 illustrates an example of the configuration of a power supply device and an image forming device. FIG. 13 is a diagram illustrating an example of the overall process. FIG. 4 is a diagram illustrating an example of a first current value. 13 is a diagram showing an example in which it is determined that the second current value has not changed by more than a predetermined value; FIG. 13 is a diagram showing an example in which it is determined that the second current value has changed to a predetermined value or more; FIG. FIG. 11 is a diagram illustrating a configuration example of a second embodiment. 13A and 13B are diagrams illustrating an example of current values and comparison results when an abnormality is detected. FIG. 2 is a diagram illustrating an example of a functional configuration.

The optimal and minimal form for implementing the invention will be described below with reference to the drawings. Note that when the same reference numerals are used in the drawings, they indicate similar configurations, and duplicated explanations will be omitted. Also, the specific examples shown in the drawings are merely examples, and the configuration may further include configurations other than those shown in the drawings.

First Embodiment
<Configuration Example of Power Supply Device and Image Forming Apparatus>
1 is a diagram showing an example of the configuration of a power supply device and an image forming apparatus. For example, the power supply device 200 has a hardware configuration including a power source 1, a primary side rectifier circuit 2, a switching circuit 3, and a secondary side rectifier circuit 4. Note that the power supply device 200 is not limited to the hardware configuration shown in the figure, and may be any device that can output an output current 204 to a load MD via a harness or the like.

The following describes an example in which the load MD is a device used for image formation. In this example, the image forming device 500 has a power supply device 200, and supplies power to the load MD by outputting an output current 204 from the power supply device 200. The image forming device 500 then operates the load MD with the supplied power to form an image.

Below, an example of a connection relationship in which the power supply device 200 is connected to the load MD via a harness as shown in the figure will be described. Specifically, the harness is connected to a connector 201 that the power supply device 200 has. The load MD is then electrically connected to the harness. Note that there may be multiple loads MD as shown in the figure.

In this example, first, the power source 1 generates power that becomes the primary voltage. Then, the primary side rectifier circuit 2, the switching circuit 3, and the secondary side rectifier circuit 4 process it to become the secondary voltage, and the voltage and current values are controlled to be as determined by the specifications, and the output current 204 is output.

The power supply device 200 has a current detection element 202 that measures the current value of the output current 204 at a position as shown in the figure. For example, the current detection element 202 is a Hall element. Note that the current detection element 202 may be installed at a position other than that shown in the figure, as long as it can measure the current value of the output current 204.

The control device 203 performs control by transmitting a control signal ST to the switching circuit 3, for example. For example, the control signal ST is a signal that stops the power supply device 200 or the entire image forming device 500.

As shown in the figure, the image forming device 500 has various loads MD. The image forming device 500 operates the loads MD with power supplied via a harness to perform various processes that are determined in advance by specifications, etc.

The image forming device 500 uses the power supplied by the harness to operate the load MD and form images.

<Overall processing example>
FIG. 2 is a diagram showing an example of the overall process. Hereinafter, a "normal" state, such as an initial state, in which the power supply device 200, the image forming device 500, and the electrical components constituting these operate according to the specifications is referred to as a "first state". On the other hand, a state in which a certain amount of time has passed since the first state is referred to as a "second state". The first state is a state prior to the second state, and may be any time as long as the power supply device 200, the image forming device 500, and the electrical components constituting these are in a "normal" state. In addition, the overall process may not be continuous between the process in the "first state" (i.e., steps S1 and S2) and the process in the "second state" (i.e., steps S3 and after). Therefore, the process in the "first state" may be completed before the process in the "second state" is performed.

In step S1, the power supply device 200 measures the current value. Hereinafter, the current value measured under the "first condition" is referred to as the "first current value."

In step S2, the power supply device 200 stores the first current value.

For example, the first current value is stored as follows:

Figure 3 is a diagram showing an example of the first current value. For example, the first current value D1 is measured and stored as shown.

The first current value D1 is measured and stored separately for each operating condition. Different operating conditions may use different loads MD, and so the first current value D1 in the "normal" state may differ for each operating condition. For example, an operating condition is the mode of the image forming device 500. The operating condition is not limited to the mode, and may be any condition in which the load or first current value used in the "normal" state is different.

The illustrated example is an example in which the first current value D1 is measured and stored when the operating condition is copy mode MCP.

For example, the first current value D1 is the average value of the current value in the copy mode MCP. In this example, as shown in the figure, the current value measured when the value stabilizes after switching to the copy mode MCP is measured and stored as the first current value D1. Note that the first current value D1 is not limited to the average value, and may be the maximum and minimum values measured in the copy mode MCP. Furthermore, a tolerance may be set for the first current value D1, assuming a certain degree of error and variation. In this way, the first current value D1 may be a value that serves as a standard for determining whether or not it is "normal," and may have a range of values.

As described above, by measuring and storing the first current value D1, the power supply device 200 can determine the current value when the device is "normal."

The "second state" is a state in which time has passed since the "first state." Note that it is preferable that the processing from step S3 onward be performed for each predetermined condition.

The specified condition may be, for example, a time condition, a condition based on the amount of load generated by the load, or a condition determined by a combination of these.

The specified conditions are criteria for implementing periodic inspections. Therefore, if you want to inspect the current value periodically and want to set the inspection interval based on time conditions, the specified conditions are set to, for example, "every month." If such specified conditions are met, the processing from step S3 onwards will be executed "every month."

The specified condition may also be the amount of load generated by the loaded MD. The amount of load is determined depending on the type of loaded MD. For example, in the case of the image forming device 500, the amount of load is the number of recording media printed. Note that the amount of load is not limited to the number of recording media, and may be any quantity that the image forming device 500 can count, such as the operating time of the loaded MD, the amount of toner used for printing, the accumulated time the power is on, etc. The specified condition is set in advance.

Therefore, the processes from step S3 onwards are repeated for each specified condition. In this way, electrical components can be checked periodically for abnormalities.

In step S3, the power supply device 200 measures the current value. Hereinafter, the current value measured under the "second condition" is referred to as the "second current value."

In step S4, the power supply device 200 determines whether the second current value has changed by a predetermined value or more with respect to the first current value D1.

The predetermined value is a reference value that determines how much the current value must deviate from the first current value D1, which is considered "normal," to be considered "abnormal." For example, the predetermined value is set in advance.

For example, the power supply unit 200 makes the following determination:

Figure 4 shows an example in which it is determined that the second current value has not changed by more than a predetermined value.

Figure 5 shows an example in which it is determined that the second current value has changed to a value equal to or greater than a predetermined value.

In step S4, the power supply device 200 compares the first current value D1 with the second current value D2 as shown in Figures 4 and 5, and determines whether the second current value has changed by a predetermined value or more compared to the first current value.

First, in steps S1 and S2, for example, the power supply device 200 measures and stores a first current value D1 as shown in FIG. 4(A) or FIG. 5(A). After such a first current value D1 is measured and stored, in step S3, the power supply device 200 measures a second current value D2 as shown in FIG. 4(B) or FIG. 5(B). Below, an example of such a first current value D1 and second current value D2 will be described.

In the example shown in FIG. 4, the second current value D2 does not change much relative to the first current value D1. In other words, FIG. 4 shows an example in which it is determined that the second current value D2 has not changed by more than a predetermined value because there is little difference between the second current value D2 and the first current value D1.

In the example shown in FIG. 5, the second current value D2 has changed by a predetermined value or more with respect to the first current value D1. In other words, FIG. 5 shows an example in which it is determined that the second current value D2 has changed by a predetermined value or more because there is a difference between the second current value D2 and the first current value D1 that is a predetermined value or more.

For example, when an abnormality occurs due to aging, the current value may increase as shown in FIG. 5(B). Therefore, the power supply device 200 can determine whether an abnormality due to aging has occurred by measuring the second current value D2 and comparing it with the first current value D1.

It is preferable that the power supply device 200 judges whether the second current value has changed by a predetermined value or more from the first current value based on the second current value D2 and the first current value D1 measured under the same operating conditions. Specifically, the examples shown in Figures 4 and 5 are examples in which both the first current value D1 and the second current value D2 are measured under the same operating conditions, namely, copy mode MCP. On the other hand, when the operating conditions, such as the mode, are different, the first current value D1, which serves as the basis for judgment, may differ. Therefore, the power supply device 200 can accurately detect an abnormality if a judgment is made by comparing current values measured under the same operating conditions.

Next, if it is determined that the change is greater than or equal to the predetermined value (YES in step S4), the power supply device 200 preferably proceeds to step S5. On the other hand, if it is determined that the change is not greater than or equal to the predetermined value (NO in step S4), the power supply device 200 ends the entire process.

In step S5, the power supply device 200 outputs a warning and performs control such as shutting down.

For example, when an abnormality such as that shown in FIG. 5 is detected and a determination is made that an abnormality has occurred, the power supply device 200 outputs a warning. The warning may be, for example, outputting a message indicating the warning to an output device possessed by the image forming device 500, outputting a signal to turn on a warning lamp, or notifying another device of the warning. In this way, when a warning is output, the user can be promptly informed that an abnormality has occurred in the power supply device 200.

Shutdown is a control to stop the power supply device 200, the image forming device 500, or some of the equipment they have. For example, it is desirable for the control device 203, etc. to control the power supply device 200 to stop supplying power using the control signal ST. In other words, when an abnormality such as that shown in Figure 5 occurs, there is often a risk of burning or the like. Therefore, it is desirable for the control device 203, etc. to operate to stop output from the power supply device 200 and protect the power supply device 200, the image forming device 500, and external devices, etc. Such an operation can avoid the risk of burning or the like.

The shutdown may also differ depending on the value of the current value. For example, when the current value is large, the control device 203 etc. performs processing to quickly output a warning and stop the output of the power supply device. On the other hand, when the current value is small, the control device 203 etc. performs processing to output a warning and stop the output of the power supply device after the image forming device finishes the ongoing processing if the image forming device is performing image formation such as copying. In such a case, the warning and control may be performed in stages, such as first quickly outputting a warning and then displaying that the output of the power supply device will be stopped when processing such as image formation is completed.

In this way, the control device 203 etc. may determine the stage or timing of execution of the protection process depending on the level of the abnormality. Note that the thresholds and stages etc. used to determine the level of the abnormality are set in advance. In this way, when protection is performed by warnings and controls etc. depending on the level of the abnormality, the power supply device 200 can perform processing according to the risk.

In addition, in the image forming device 500, it is desirable for the power supply device 200 to perform abnormality detection and protection, etc. based on a reference value according to the mode of the image forming device.

The power supply device 200 may predict the time when an abnormality will occur based on the tendency of deterioration over time. As shown in FIG. 5, the current value often tends to increase due to deterioration over time. Therefore, based on the measurement results, it is possible to calculate how much the current value has increased per unit time based on the time that has elapsed from the initial state to the present time. Then, assuming that the amount of increase in the current value per unit time is constant, the power supply device 200 predicts the time when the second current value D2 at the present time will increase in a similar manner and become a value equal to or greater than a predetermined value relative to the first current value D1. In this way, the power supply device 200 may predict the time when an abnormality is likely to occur. The time when an abnormality is likely to occur may be predicted in units of load amount, not by time. In this way, if the time when an abnormality is likely to occur is predicted, a breakdown can be prevented.

Second Embodiment
The second embodiment differs from the first embodiment in the following configuration.

Figure 6 is a diagram showing an example of the configuration of the second embodiment. Compared to the first embodiment, as shown in the figure, the second embodiment differs in that the harness 300 has a first hall element HL1 on the power supply side and a second hall element HL2 on the load side, and a comparator 2001 is added to the hardware configuration. Below, the differences will be mainly described, and redundant descriptions of the same configuration as the first embodiment will be omitted.

With the first hall element HL1 and the second hall element HL2, the current value can be detected at multiple points in the harness 300. Hereinafter, the current value measured by the first hall element HL1 will be referred to as the "upstream current value," and the current value measured by the second hall element HL2 will be referred to as the "downstream current value."

Figure 7 shows an example of the current value and comparison results when an abnormality is detected.

Figure 7 (A) is an example of upstream current values.

Figure 7 (B) is an example of downstream current values.

Figure 7 (C) is an example of the results of comparing the upstream current value and the downstream current value. For example, the comparison result is obtained by calculating the difference between the upstream current value and the downstream current value.

For example, if there is an abnormality, such as a short circuit, in the harness 300, the current value is detected as shown in the figure, and the abnormality is detected.

The short circuit may be, for example, a rare short circuit (an intermittent short circuit). When such an abnormality occurs, a current due to a rare short circuit (hereinafter referred to as "short circuit current 205") is generated, as shown in Figures 1 and 6.

For example, when an abnormality such as a layer short occurs, a current is generated due to the abnormality (hereinafter referred to as "abnormal current ED") as shown in FIG. 7(B). For example, when such an abnormality occurs, a difference occurs between the upstream current value and the downstream current value as shown in FIG. 7(C).

This difference is the comparison difference DF, which is the comparison of the upstream current value and the downstream current value, as shown in FIG. 7(C). If this comparison difference DF is equal to or greater than a preset reference value BV, the comparator 2001 detects an abnormality.

In addition, it is desirable that the comparator 2001 detects an abnormality when at least one of the upstream current value and the downstream current value is equal to or greater than the threshold value TH. First, as shown in the figure, the threshold value TH is set in advance. Then, when either the upstream current value or the downstream current value is equal to or greater than the threshold value TH, i.e., when an overcurrent flows, the comparator 2001 may detect an abnormality.

Apart from the abnormal current ED, if the upstream current value or downstream current value is a high current value equal to or greater than the threshold value TH, there is a high possibility that an abnormality has occurred in the harness 300, etc. Therefore, if a further determination is made as to whether at least one of the upstream current value and downstream current value is equal to or greater than the threshold value TH, the abnormality can be detected more accurately.

As shown in the figure, if the configuration can detect abnormal current ED by comparing the upstream current value with the downstream current value, it is possible to detect abnormalities such as layer shorts. If such detection is possible, it is possible to detect abnormal current even in a current range that cannot be detected by fuses, etc. This makes it possible to prevent the harness from burning out, etc.

The modes of the image forming device 500 are, for example, standby mode, reading mode, print mode, copy mode, etc. In other words, the mode may be information indicating what kind of load is used. For example, in standby mode, loads such as the transfer device, reading device, and paper feed device do not consume much power. On the other hand, in print mode or copy mode, which are operating modes in which loads such as the transfer device and paper feed device are operating, they often consume more power than standby mode, etc.

Therefore, it is desirable that the criteria for detecting an abnormality differ depending on the mode. Specifically, it is desirable that the reference value BV, etc. be set so as to detect when a current value of 30% or more of the state considered to be "normal" flows. Such a current value often results in an overcurrent exceeding the regulations flowing through the harness 300 and components such as the motor. Therefore, even if the current value changes depending on the mode, abnormalities can be detected with high accuracy. Furthermore, detection can prevent burning and deterioration of components, etc.

<Modification>
The detection of an abnormality may be performed based on the time the abnormality continues. Specifically, first, a "detection duration" that is a threshold time for detecting an abnormality is set in advance. Then, when a state that is judged to be "abnormal", that is, when the abnormality continues for more than the detection duration, may be detected as an abnormality. In this way, when an abnormal state continues for a certain amount of time, there is a high possibility that an abnormality has occurred. Therefore, in such a case, if protection is performed to stop the output of a warning and the output of the power supply device, the electrical components, etc. can be protected more. Also, even if an "abnormal" state occurs momentarily due to noise, etc., there are cases where the impact on electrical components such as the harness 300 is small. On the other hand, when an abnormality is detected continuously, the impact is often large. In other words, when an abnormality is detected based on time, the abnormality can be detected with high accuracy even in the presence of noise, etc.

Furthermore, in the case of a device having multiple loads such as an image forming device, it is desirable to detect an abnormality while all of the multiple loads are operating.

When multiple loads are all operating, the power consumed by the loads is often at its maximum. Thus, when the power consumption is large, if there are multiple harnesses, paths, and power supplies, there is a high possibility that many harnesses, paths, power supplies, etc. will be used. Therefore, if an abnormality is detected while multiple loads are all operating, it is often possible to detect the abnormality in various locations. Therefore, if the power supply unit detects an abnormality while multiple loads are all operating, it is possible to detect the abnormality in various locations in a short period of time.

<Functional configuration example>
8 is a diagram showing an example of a functional configuration. As shown in the figure, the power supply device 200 has a functional configuration including, for example, an output unit FN1, a measurement unit FN2, a storage unit FN3, and a determination unit FN4. Also, the power supply device 200 has a functional configuration including, for example, a control unit FN5 and a warning unit FN6.

The output unit FN1 is realized by the power source 1, etc. Furthermore, the measurement unit FN2 is realized by a measuring device that measures the current value of the current detection element 202, etc. Furthermore, the memory unit FN3, judgment unit FN4, control unit FN5, warning unit FN6, etc. are realized by the operation of the calculation unit, control unit, storage unit, input device, output device, etc. of the control unit 203 in cooperation with each other.

<Other embodiments>
The above-described devices do not have to be a single device, that is, each device may be made up of multiple devices.

The power supply device 200 may be applied to devices other than image forming devices. In other words, the type of load MD may be a device used for purposes other than image formation.

Although one example of an embodiment has been described above, the present invention is not limited to the above embodiment. In other words, various modifications and improvements are possible within the scope of the present invention.

1 Power supply 2 Primary side rectifier circuit 3 Switching circuit 4 Secondary side rectifier circuit 200 Power supply device 201 Connector 202 Current detection element 203 Control device 204 Output current 205 Short circuit current 300 Harness 500 Image forming device 2001 Comparator BV Reference value D1 First current value D2 Second current value DF Comparison difference ED Abnormal current FN1 Output section FN2 Measurement section FN3 Memory section FN4 Determination section FN5 Control section FN6 Warning section HL1 First hall element HL2 Second hall element MCP Copy mode MD Load ST Control signal TH Threshold value

JP 2006-48481 A

Claims (5)

an output section that outputs an output current to a connected load;
A measurement unit that measures a current value of the output current, the measurement unit having a first measurement unit ;
a storage unit configured to store a first current value, which is the current value measured by the first measurement unit in a first state;
a determination unit that compares a second current value, which is the current value measured by the first measurement unit in a second state that is a state in which a time has elapsed since the first state, with the first current value and determines whether or not the second current value has changed from the first current value by a predetermined value or more;
A power supply device comprising:
the first measurement unit is provided in the power supply device ,
the determination unit determines that an abnormality due to aging has occurred when, in the second state, the second current value measured under the same operating conditions as the operating conditions of the load under which the first current value was measured in the first state has changed from the first current value by a predetermined value or more;
Detecting an abnormality when a difference between a current measured by the first measuring unit and a current measured by a second measuring unit provided on the load side is equal to or greater than a preset reference value;
The first current value is stored for each operating condition of the load;
The measurement unit measures the first current value and the second current value under the same operating condition. The power supply device according to claim 1 , further comprising a control unit that performs a shutdown based on a result of the determination by the determination unit. The power supply device according to claim 1 , wherein the first state is an initial state. The power supply device according to claim 1 , further comprising a warning unit that outputs a warning based on a result of the determination made by the determination unit. 5. An image forming apparatus comprising the power supply device according to claim 1.

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