JP7363230B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus .

2. Description of the Related Art Conventionally, methods are known for detecting the occurrence of an abnormality in a harness that supplies power to electronic devices and the like.

In the wire harness, short circuits such as so-called dead shorts or rare shorts occur due to deterioration over time, contact, wear, or the like. Therefore, a thermal fuse that melts when a certain temperature abnormality occurs is disposed inside the wire harness or disposed adjacent to the wire harness. A method of avoiding deterioration of a wire harness due to a layer short or the like in this manner is known (see, for example, Patent Document 1).

However, with conventional methods, abnormalities are often detected only at the point where power is output from the power source to the harness. In such a configuration, when an overcurrent is output from the power supply to the harness, that is, when the current value exceeds a certain level, it is determined that an overcurrent is flowing, and the protection device is activated. With the operation of such a protection device, it may not be possible to detect an abnormality such as a short circuit in the harness.

One aspect of the present invention aims to detect an abnormality occurring in a harness.

An image forming apparatus according to an embodiment of the present invention includes an abnormality detection device that detects an abnormality occurring in a harness that supplies power from a power supply device to a load, and forms an image using a plurality of the loads. There it is,
The abnormality detection device includes:
a first detection unit that detects a first current value that is a current value of the electric power detected at a first location;
a second detection unit that detects a second current value that is a current value of the electric power detected at a second location that is closer to the load than the first location;
An abnormality detection unit is provided that compares the first current value and the second current value and detects an abnormality based on a reference value depending on an operation mode in which the load is operated .

According to embodiments of the present invention, abnormalities occurring in the harness can be detected.

It is a figure showing an example of composition of a harness abnormality detection device. It is a flowchart which shows an example of overall processing. It is a figure which shows the example of a current value and a comparison result when no abnormality is detected. It is a figure which shows the example of a current value and a comparison result when an abnormality is detected. It is a figure showing an example of composition of a harness abnormality detection device. 1 is a diagram showing a configuration example of an image forming apparatus. It is a diagram showing an example of a functional configuration. It is a figure showing a comparative example.

Hereinafter, the optimum and minimum form for carrying out the invention will be described with reference to the drawings. Note that in the drawings, when the same reference numerals are used, it indicates the same configuration, and redundant explanation will be omitted. Further, the illustrated specific example is merely an example, and the configuration may further include configurations other than those illustrated.

<First embodiment>
FIG. 1 is a diagram showing a configuration example of a harness abnormality detection device. For example, a harness abnormality detection device (hereinafter simply referred to as “abnormality detection device 100”) has a hardware configuration including a first current value detector 200, a second current value detector 201, a comparator 202, and the like.

Furthermore, it is desirable that the protection device 101 has a hardware configuration that includes the abnormality detection device 100 and a control device 203. Hereinafter, a configuration example in which a control device 203 is provided as shown in the figure will be described.

The abnormality detection device 100 is connected to, for example, a power supply device 10 having a circuit configuration as illustrated.

The power supply device 10 has a hardware configuration including, for example, a power supply 1, a primary rectifier circuit 2, a switching circuit 3, a secondary rectifier circuit 4, and the like. Note that the power supply device 10 is not limited to the hardware configuration shown in the figure, and may be any device as long as it can output power via the harness 300.

Specifically, first, the power supply 1 generates electric power that becomes a primary voltage. Then, the primary rectifier circuit 2, switching circuit 3, and secondary rectifier circuit 4 process the voltage to become a secondary voltage, control it to a predetermined voltage value and current value, and output power. Ru.

The first current value detector 200 and the second current value detector 201 are, for example, ammeters. Note that the first current value detector 200 and the second current value detector 201 do not need to be installed at the illustrated positions. That is, the first current value detector 200 and the second current value detector 201 may be installed in any position as long as the harness to be detected is sandwiched between the power supply side and the load side.

In this way, all or part of the harness 300 to be detected may be present between the first current value detector 200 and the second current value detector 201. An example in which the external device 500 includes the second current value detector 201 will be described below.

That is, in the configuration example described below, the first current value detector 200 detects the first current value at a location between the power supply device 10 and the harness 300, which is an example of the first location. . On the other hand, in this example, the second current value detector 201 detects the second current value at a location between the harness 300 and the load MD, which is an example of a second location that is closer to the load MD than the first location. This will be explained using an example.

The comparator 202 and the control device 203 are, for example, electronic circuits. Note that the comparator 202 and the control device 203 do not have to be separate devices. That is, the comparator 202 and the control device 203 may be one electronic circuit or may be separate electronic circuits.

For example, the control device 203 performs control by transmitting a control signal to the switching circuit 3 and the like. For example, the control signal is a signal for stopping the power supply device 10, or the like.

External device 500 has various loads MD as shown. Then, the external device 500 operates the load MD with the power supplied via the harness 300 to perform various processes in order to perform processes determined in advance by specifications and the like.

External device 500 is, for example, an image forming device. That is, the external device 500 uses the power supplied by the harness 300 to operate the load MD to form an image.

<Overall processing example>
FIG. 2 is a flowchart showing an example of overall processing.

In step S1, the first current value detector 200 detects a first current value.

In step S2, the second current value detector 201 detects a second current value.

In step S3, the comparator 202 compares the first current value and the second current value.

In step S4, the comparator 202 determines whether an abnormality is detected.

Next, when an abnormality is detected (YES in step S4), it is desirable for the control device 203 to proceed to step S5. On the other hand, if no abnormality is detected (NO in step S4), the abnormality detection device 100 ends the entire process. Note that the entire process may be repeatedly performed periodically.

In step S5, the control device 203 performs processing to protect the power supply device 10, the external device 500, etc., such as outputting a warning and controlling the power supply device 10 to stop.

Note that the overall processing does not need to be performed in the order shown. For example, the first current value and the second current value may be detected in sequence. Furthermore, detection and determination may be performed repeatedly.

<Processing result example>
FIG. 3 is a diagram showing an example of a current value and a comparison result when no abnormality is detected.

FIG. 3(A) is an example of the detection result of the first current value, that is, the result obtained when step S1 is performed.

FIG. 3(B) is an example of the detection result of the second current value, that is, the result obtained when step S2 is performed.

FIG. 3(C) is an example of the result of comparing the first current value and the second current value. For example, the comparison result is obtained by calculating the difference between the first current value and the second current value.

In the illustrated example, the first current value and the second current value are the same. Therefore, as a result of the comparison based on the difference, since the current values are the same, it is determined that there is no difference. With such a comparison result, no abnormality is detected in the overall process (NO in step S4).

FIG. 4 is a diagram showing an example of a current value and a comparison result when an abnormality is detected. For example, if there is an abnormality such as a short circuit in the harness 300, a current value as shown in the figure is detected and the abnormality is detected.

The short circuit is, for example, a rare short circuit (an intermittent short circuit). When such an abnormality occurs, for example, as shown in FIG. 1, a current due to a layer short circuit (hereinafter referred to as "short current 400") or the like is generated. Such a short current 400 often causes a phenomenon different from that in the case of FIG.

For example, when there is an abnormality such as such a layer short, there is a current generated due to the abnormality (hereinafter referred to as "abnormal current ED"), as shown in FIG. 4(B). On the other hand, in this example, the first current value is the same as when there is no abnormality. For example, when such an abnormality occurs, as shown in the figure, a difference occurs between the first current value and the second current value by an amount corresponding to the abnormal current ED.

This difference becomes a comparison difference DF that compares the first current value and the second current value, as shown in FIG. 4(C). If this comparison difference DF is greater than or equal to the preset reference value BV, the comparator 202 detects an abnormality (YES in step S4).

Moreover, it is desirable that the comparator 202 detects an abnormality when at least one of the first current value and the second current value is a current equal to or higher than the threshold value TH. First, as shown in the figure, a threshold value TH is set in advance. Then, when the first current value or the second current value is greater than or equal to the threshold value TH, that is, when an overcurrent flows, the comparator 202 may detect an abnormality.

Apart from the abnormal current ED, when the first current value or the second current value becomes a high current value equal to or higher than the threshold value TH, it is likely that an abnormality has occurred in the harness 300. Therefore, if it is further determined whether at least one of the first current value and the second current value is a current equal to or greater than the threshold value TH, an abnormality can be detected with higher accuracy.

As shown in the figure, if the configuration is such that an abnormal current ED can be detected by comparing the first current value and the second current value, it is possible to detect a layer short or the like. If such detection is possible, abnormal current can be detected even in a range of current that cannot be detected by fuses or the like. Therefore, the harness can be prevented from being burnt out.

<Second embodiment>
FIG. 5 is a diagram showing a configuration example of a harness abnormality detection device. This embodiment differs from the first embodiment in that the current value detector is a current detection element. The differences will be mainly explained below.

The current detection element is, for example, a Hall element. Therefore, as shown in the figure, the harness 300 may have a hardware configuration in which the first Hall element HL1 is installed on the power supply side and the second Hall element HL2 is installed on the load side.

The first Hall element HL1 and the second Hall element HL2 can also detect the first current value and the second current value, for example, as shown in FIG. 4. That is, similarly to the first embodiment, an abnormality can be detected by comparing the first current value and the second current value.

<Example of image forming device>
FIG. 6 is a diagram showing a configuration example of an image forming apparatus. As illustrated, the abnormality detection apparatus 100 may be applied to, for example, an image forming apparatus 501.

In the case of the image forming apparatus 501, the loads include the transfer device MD1, the reading device MD2, the paper feeding device MD3, and the like. That is, if the external device is the image forming apparatus 501, it performs processes such as transfer, reading, and paper feeding, and executes image formation or image reading. Note that the load may be a module that performs other processing.

Furthermore, if the external device is a device capable of receiving a warning, such as the image forming apparatus 501, it is preferable that the control device 203 or the like outputs a warning to the image forming apparatus 501 when an abnormality is detected.

Specifically, when an abnormality as shown in FIG. 4 is detected, it is desirable that the control device 203 or the like output a message indicating that the abnormality has been detected on a display device or the like. When such a warning is output, the user of the image forming apparatus 501 can quickly know that an abnormality has occurred.

Furthermore, in the case where a warning is to be output, the control device 203 and the like preferably control the output of the power supply device 10 to be stopped using the stop signal ST. That is, when there is an abnormality as shown in FIG. 4, there is often a risk of burnout or the like in the harness 300 or the like. Therefore, it is desirable that the control device 203 and the like operate to stop the output of the power supply device 10 to protect the harness 300, external devices, and the like. With such an operation, risks such as burnout can be avoided.

Further, the protection process may differ depending on the current value of the abnormal current ED, etc. For example, when the abnormal current ED is a large value, the control device 203 and the like immediately output a warning and stop the output of the power supply device 10. On the other hand, if the abnormal current ED is a small value, if the image forming apparatus 501 is performing image formation such as copying, the control device 203 or the like outputs a warning after completing the process in progress. A process of stopping the output of the power supply device 10 is performed. In such a case, first, a warning is outputted immediately, and the warning and control are performed in stages so that the output of the power supply device 10 is stopped at the timing when processing such as image formation is completed. May be done.

In this way, depending on the degree of abnormality, the control device 203 and the like may decide the timing to perform the protection process in stages or at the timing. Note that the threshold value, stage, etc. used for determining the degree of abnormality are set in advance. In this way, when protection is performed by warning, control, etc. depending on the degree of abnormality, the protection device 101 can perform processing according to the risk.

Furthermore, when the external device is the image forming apparatus 501, it is preferable that the protection apparatus 101 performs abnormality detection, protection, etc. based on the reference value BV according to the operation mode of the image forming apparatus 501.

The operation mode is, for example, standby mode, reading mode, print mode, copy mode, or the like. That is, the operation mode may be information indicating what kind of load the configuration uses. For example, in the standby mode, loads such as the transfer device MD1, the reading device MD2, and the paper feeding device MD3 do not consume much power. On the other hand, the print mode or the copy mode is an operation mode in which loads such as the transfer device MD1 and the paper feed device MD3 operate, and therefore, compared to the standby mode and the like, a large amount of power is often consumed.

Therefore, it is desirable that the standard for detecting an abnormality, that is, the standard value BV, differ depending on the operating mode. Specifically, the reference value BV is desirably set so as to detect a case where a current value of 30% or more of the "normal" state flows. With such a current value, an overcurrent exceeding the regulation often flows through components such as the harness 300 and the motor. Therefore, even if the current value changes depending on the operation mode, abnormalities can be detected with high accuracy. The detection can prevent burnout and deterioration of parts.

<Modified example>
Detection of an abnormality may be performed based on the time period during which the abnormality continues. Specifically, first, a "predetermined time" that is a threshold for detecting an abnormality is set in advance. Then, when a state determined to be "abnormal", that is, a case where the abnormal current ED continues for a predetermined period of time or more, is detected, an abnormality may be detected. In this way, if the abnormal condition continues for a certain amount of time, such as for a predetermined period of time or more, there is a high possibility that an abnormality has occurred. Therefore, in such a case, if protection such as stopping the output of a warning and the output of the power supply device 10 is performed, the external device etc. can be further protected. Further, even if a momentary "abnormal" state occurs due to noise or the like, the harness 300 and external devices may be less affected. On the other hand, when abnormal current ED is continuously detected for a predetermined period of time or more, the influence is often large. That is, if an abnormality is detected based on time, the abnormality can be detected with high accuracy even if there is noise or the like.

Further, in the case of an external device having multiple loads such as the image forming apparatus 501, abnormality detection is preferably performed while all of the multiple loads are operating.

While all of the multiple loads are operating, the power consumed by the loads is often at its maximum. In this way, when the power consumption is large and there are multiple harnesses, routes, power supplies, etc., there is a high possibility that many harnesses, routes, power supplies, etc. will be used. Therefore, if an abnormality is detected while all multiple loads are operating, it is often possible to detect the abnormality at various locations. Therefore, if the abnormality detection device 100 detects an abnormality while all the plurality of loads are operating, the abnormality detection device 100 can detect the abnormality at various locations in a short time.

<Functional configuration example>
FIG. 7 is a diagram showing an example of a functional configuration. As illustrated, the abnormality detection device 100 has a functional configuration including, for example, a first detection section FN1, a second detection section FN2, an abnormality detection section FN3, and the like. Further, the protection device 101 has a functional configuration including, for example, an output section FN4, a control section FN5, etc., as shown in the figure.

The first detection unit FN1 performs a first detection procedure of detecting a first current value detected at a first location. For example, the first detection unit FN1 is realized by the first current value detector 200 or the like.

The second detection unit FN2 performs a second detection procedure of detecting a second current value detected at a second location that is closer to the load than the first location. For example, the second detection unit FN2 is realized by the second current value detector 201 or the like.

The abnormality detection unit FN3 performs an abnormality detection procedure of comparing the first current value and the second current value to detect an abnormality. For example, the abnormality detection unit FN3 is realized by the comparator 202 or the like.

The output unit FN4 performs an output procedure of outputting a warning etc. when the abnormality detection unit FN3 detects an abnormality. For example, the output unit FN4 is realized by the control device 203 or the like.

The control unit FN5 performs a control procedure to stop the output from the power supply device. For example, the control unit FN5 is realized by the control device 203 or the like.

With the above functional configuration, the abnormality detection device 100 can compare the first current value and the second current value. Therefore, abnormalities occurring in the harness 300 can be detected as shown in FIG. 4(C) and the like.

When such a detection is made, the protection device 101 can output a warning or perform control such as stopping the output from the power supply device. The protection device 101 can prevent losses due to burnout, short circuit, etc. of the harness 300, external devices, etc.

<Comparative example>
FIG. 8 is a diagram showing a comparative example. In the illustrated comparative example, the current value is detected by a current value detector 200A. That is, in the comparative example, the current value is detected at one location of the current value detector 200A. With such a configuration, it is difficult to perform a comparison as shown in FIG. Therefore, it may be difficult to detect an abnormality unless it causes a large current value to be generated.

<Other embodiments>
The device described above does not need to be a single device. That is, each device may be composed of a plurality of devices.

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

10 Power supply device 100 Abnormality detection device 101 Protective device 200 First current value detector 201 Second current value detector 202 Comparator 203 Control device 300 Harness 500 External device 501 Image forming device BV Reference value DF Comparison difference ED Abnormal current FN1 th 1 detection section FN2 2nd detection section FN3 Abnormality detection section FN4 Output section FN5 Control section HL1 1st Hall element HL2 2nd Hall element MD Load MD1 Transfer device MD2 Reading device MD3 Paper feeding device ST Stop signal TH Threshold

Japanese Patent Application Publication No. 11-31446

Claims (4)

An image forming apparatus comprising a harness abnormality detection device for detecting an abnormality occurring in a harness that supplies power from a power supply device to a load, and forming an image using a plurality of the loads, the image forming apparatus comprising:
The abnormality detection device includes:
a first detection unit that detects a first current value that is a current value of the electric power detected at a first location;
a second detection unit that detects a second current value that is a current value of the electric power detected at a second location that is closer to the load than the first location;
an abnormality detection unit that compares the first current value and the second current value and detects an abnormality based on a reference value corresponding to an operation mode in which the load is operated.
Image forming device . an output unit that outputs a warning to an external device when the abnormality detection unit detects an abnormality;
A control unit that stops output by the power supply device when at least one of the first current value and the second current value is a current value equal to or higher than a threshold value.
The image forming apparatus according to claim 1. an output unit that outputs a warning to an external device when the abnormality detection unit detects that the abnormality has continued for a predetermined period of time or more;
and a control unit that stops output from the power supply device when the abnormality detection unit detects that the abnormality has continued for a predetermined period of time or more.
The image forming apparatus according to claim 1. The abnormality detection unit detects an abnormality while all of the plurality of loads are operating.
The image forming apparatus according to any one of claims 1 to 3 .

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