JPH04130362A - Self-diagnostic and self-repairing system for image formation device - Google Patents

Abstract

PURPOSE:To repair the fault of the device only by selecting and operating an actuator means by discriminating whether or not there is the fault when state data are measured and inputted, and reasoning the cause of the fault. CONSTITUTION:A digital signal/symbol conversion part 11 converts signals from sensors 1a - 1c into symbols based reference value data in an object model storage part 14 and a fault diagnostic part 12 evaluates the symbols to discriminate whether or not there is the fault and specify its symptoms. At this time, fault diagnostic knowledge in the storage part 14 is utilized. In case of the fault, the diagnostic part 13 retrieves parameters which cause the fault according to qualitative data in the storage part 14 and a fault simulation part 13 simulates the fault state. Further, the diagnostic part 12 judges the adequacy of the retrieved parameter. The above processes are performed for the plural retrieved parameters. Then the fault symptoms and fault cause are determined according to the results.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a self-diagnosis and repair system for an image forming apparatus. More specifically, using artificial intelligence and knowledge engineering, which have been actively researched in recent years,
The present invention relates to a device or system that can self-diagnose and repair the operating state of an image forming device.

<Conventional technology> In the development field of precision machinery and industrial machinery, recent efforts have been made to save labor in maintenance work and extend automatic operation.
Artificial Intelligence
CE: Research on expert systems using so-called AI technology is actively being conducted. Some expert systems can self-diagnose whether a device has malfunctioned or not.
There are also some devices that self-repair any malfunctions that occur.

<Problem to be solved by the invention> However, in the fault diagnosis system using the conventional expert system, (a) the knowledge is not versatile and fault diagnosis cannot be performed for various targets, and (b) unknown (c) As the target becomes more complex, the amount of knowledge required for fault diagnosis increases explosively;
Limitations were pointed out, including (d) difficulty in realizing it, and (d) difficulty in acquiring knowledge.

More specifically, conventional automatic adjustment systems and fault diagnosis systems basically operate corresponding actuators based on the outputs of the sensors. In other words, a type of automatic adjustment and failure diagnosis has been performed using a predetermined combination of sensors and actuators. Therefore, basically, each sensor corresponds to a specific actuator, and the relationship between the two is fixed.

Therefore, (1) The relationship between sensor parameters and actuator parameters must be clearly expressed numerically.

(2) For the reason mentioned in (1) above, the relationship between sensor parameters and actuator parameters is strongly dependent on the object and lacks versatility. In other words, it cannot be used for various objects.

(3) The relationship between parameters between each sensor or between parameters between each actuator is irrelevant to control.

Therefore, only simple control can be performed based only on the relationship between the corresponding sensor parameters and actuator parameters, and the types of failures that can be handled are limited in advance.

In other words, it is necessary to predict possible failures at the design stage and include a mechanism for dealing with such failures; unknown failures cannot be handled.

(4) For the reason (3) above, it is not possible to predict the side effects on the parameters of other actuators that may be caused by manipulating the parameters of any actuator.

There were problems such as.

In this way, in conventional automatic adjustment systems and fault diagnosis systems, predicted failure A is caused by sensor A and actuator A.
The predicted failure B is performed based on the set A of the sensor B and the actuator B, and the predicted failure C is performed based on the set B of the sensor B and the actuator B.
Fault diagnosis was performed based on the set C of the sensor C and actuator C, respectively, and the fault repair was performed based on the diagnosis.

The present invention was made against the background of such prior art, and it is an object of the present invention to provide a novel self-diagnosis and repair system for an image forming apparatus that eliminates the drawbacks of the prior art.

Means for Solving the Problems> The present invention relates to an image forming apparatus that embodies image data to generate a visible image, and is an image forming apparatus that changes the functional state of the image forming apparatus and eliminates the cause of failure. A self-diagnosis and repair system for an apparatus including a plurality of actuator means capable of expressing the image forming apparatus as a combination of a plurality of elements, including characteristic data representing the characteristics of the image forming apparatus, and the behavior or behavior of each element. A predetermined adjustment range is set for a storage means in which qualitative data qualitatively representing attributes and coupling relationships between each element and fault diagnosis knowledge are stored, and for a predetermined actuator means among the plurality of actuator means. adjustment range setting means, adjustment state output means for detecting and outputting the adjustment state of a predetermined actuator means among the plurality of actuator means, data input means, and state data representing the functional state of the image forming apparatus from the data input means. failure determination means for determining whether the image forming apparatus is normal or abnormal based on the status data, characteristic data stored in the storage means, and failure diagnosis knowledge in response to a given condition; In response to determining that the means or the image forming apparatus is abnormal, the adjustment state and adjustment range setting means of the actuator means are set based on the qualitative data and fault diagnosis knowledge stored in the storage means and the adjustment state output means. The present invention is characterized in that it includes a fault diagnosis means for inferring the cause of the fault based on a comparison of the adjusted adjustment ranges of the actuators.

According to the present invention, in response to the status data being given from the data input means, the given status data is compared with, for example, reference data as characteristic data, and is determined whether the given status data is relatively low or low. Depending on whether it is relatively high, it is determined that a failure has occurred.

The status data given from the data input means represents the functional status of the image forming apparatus, and this status data is data that is manually measured and input by, for example, a service person.

When a failure occurs, the qualitative data and failure diagnosis knowledge stored in the storage means and the adjustment state of the actuator means given from the adjustment state output means and the adjustment range of the actuator set in the adjustment range setting means are determined. Based on the comparison, the cause of the occurring failure is inferred, and which component of the image forming apparatus has the abnormality is output.

A service person or the like can easily repair the failure by operating the actuator means with reference to the above output.

Qualitative data is not data specific to the image forming apparatus, but data that is common to many image forming apparatuses and is qualitatively expressed. Therefore, the self-diagnosis and repair system according to the present invention is different from It can be easily incorporated into various types of image forming apparatuses.

<Embodiment> Overview of System Configuration FIG. 1 is a block diagram showing the system configuration of an embodiment of the present invention. This system includes multiple sensors la, lb installed on the target machine.

1c and a plurality of actuators 6a, 6b, and 6c for changing the functional state of the target machine.

The plurality of sensors la, lb, and lc are each for detecting a change in an element of the target machine or a state related to the machine elements caused by the operation of the target machine.

Multiple sensors la, lb.

Information taken in from each IC is amplified by an amplifier circuit 2, converted from an analog signal to a digital signal by an A/D conversion circuit 3, and provided to a system control circuit 10.

The system control circuit 10 includes a digital signal/symbol conversion section 11, a fault diagnosis section 12, a fault simulation section 13, a target model storage section 14, a repair planning section 15, and a symbol/digital signal conversion section 16.

The digital signal/symbol conversion section 11 is for converting the digital signal provided from the A/D conversion circuit 3 into qualitative information. That is, a digital signal, for example, normal.

A conversion function is provided to convert to any of the three symbols, high and low. Sensor la, lb,
Converting the signal provided from the lc into such qualitative information symbolized facilitates the approach to fault diagnosis. Note that the symbols are not limited to normal, high, and low as in this example, but may be other expressions such as on and off or A, B, C, and D. When the digital signal is converted into a symbol in the converting section 11, characteristic data specific to the target machine stored in the target model storage section 4 is referred to. Details of this feature data and signal conversion will be described later.

The failure diagnosis section 12 and the failure simulation section 13 are
By comparing the symbols converted by the digital signal/symbol conversion unit 11 with the fault diagnosis knowledge stored in the target model storage unit 14, the presence or absence of a fault is determined and fault diagnosis is performed.As a result, This is a component that expresses and outputs the failure state of the target machine using qualitative information, that is, symbols.

The repair planning unit 15 is a component for inferring a repair plan for repairing a failure when a failure occurs and deriving a repair work. In inferring the repair plan and deriving the repair work, a qualitative pig (described in detail later) stored in the target model storage unit 14 is utilized.

The methods of fault diagnosis and fault simulation, inference of a repair plan, and derivation of a repair work in the fault diagnosis section 12, fault simulation section 13, and repair planning section 15 will be described in detail later.

The repair work output from the repair planning unit 15 is represented by the symbol /
The digital signal converter 16 refers to the information stored in the target model storage 14 and converts it into a digital signal.

The digital signal is then converted from a digital signal to an analog signal by a D/A conversion circuit 4 and is provided to an actuator control circuit 5. The actuator control circuit 5 controls a plurality of actuators 6a, 6b, based on an applied analog signal, that is, an actuator control command.
6c is selectively activated to perform repair work.

FIG. 2 is a flowchart showing the processing of the system control circuit 10 in FIG. Next, with reference to FIG. 2, an overview of the processing of the system control circuit 10 shown in FIG. 1 will be explained.

The detection signal of the sensor la, lb or IC is amplified,
and is converted into a digital signal and read into the system control circuit 10, for example, every predetermined read cycle (
Step Sl).

The read digital signal is converted into symbols in the digital signal/symbol converter 11 (step S2
). This symbolization is performed based on characteristic data preset in the target model storage unit 14, that is, reference value data specific to the target machine. For example, the output ranges of the sensors la, lb, and lc are set in the target model storage unit 14 as reference value data specific to the target machine as follows.

That is, sensor 1a: less than - low ~ ka2 Otori exceeds normal - less than high - low ~ kb2 - exceeds normal - less than high - low ~ kc2 - exceeds normal - high output ka output ka output ka2 sensor 1b = output kb output kb output kb2 sensor 1c: output kc output kc output kc2 It is set. The digital/symbol conversion unit 11 converts the sensors 1a to 1c based on reference value data specific to the target machine set in the target model storage unit 14.
Converts the digital signal from the device into a symbol of ``low,''``normal,'' or ``high.''

Next, the converted symbol is evaluated in the fault diagnosis unit 12, and the presence or absence of a fault is determined and the fault symptom is specified (step S3). The target model storage unit 1 is used to determine the presence or absence of a failure by evaluating symbols and to identify failure symptoms.
The fault diagnosis knowledge stored in 4 is utilized. Fault diagnosis knowledge is, for example, a setting condition that a specific parameter must be normal, for example. If the specific parameter is not normal, there is a failure.
The failure symptom is determined based on the specific parameter. If there is no failure, step Sl
, S2 and S3 are repeated.

If it is determined in step S3 that there is a failure,
The state of the target machine is inferred, that is, fault diagnosis and fault state simulation are performed (step S4). Specifically, the failure diagnosis unit 12 uses the qualitative data stored in the target model storage unit 14 that qualitatively represents the behavior or attributes of each element constituting the device and the coupling relationship between each element. , a parameter causing the failure is searched for, and the failure condition is simulated in the failure simulation section 13 on the assumption that the searched parameter is the cause of the failure.

Furthermore, the failure diagnosis section 12 compares the simulation results with the current parameter values to determine the validity of the assumption that the retrieved parameter is the cause of the failure. The above processing is performed for multiple parameters to be searched.

As a result of the failure determination, failure diagnosis, and failure state simulation, the failure symptoms and failure causes of the target machine are determined (step S5). Here, failure symptoms include the output status of the target machine (for example, in the case of a copying machine,
The cause of the failure is,
This is a change in the mechanism or structure of the target machine that causes the symbol to change (for example, in the case of a copying machine, a ``decrease in the light intensity of a halogen lamp'', etc.).

Next, the repair planning unit 15 infers a repair method. In this inference, a simulation of the influence of repair is also performed (step S6).

Then, a repair plan is determined (step S7), and control instructions are developed based on the determined repair plan (step S8). When developing actual control commands, characteristic data unique to the device, such as limit values for actuator operation, is read out from the target model storage unit 14 and utilized.

The developed control command is converted into an analog signal and given to the actuator control circuit 5, and repair control is executed (step S9). Control then ends.

Next, we will explain how to infer failure diagnosis and repair plans.
A detailed explanation will be given with reference to specific examples.

In the following description, as an example, a method will be described in which the peripheral area of the photoreceptor drum in a small-sized ordinary copying machine is used as the target machine.

FIG. 3 is an illustrative diagram showing a specific target machine. In FIG. 3, 21 is a photosensitive drum, 22 is a main charger, 23 is a halogen lamp for illuminating the original, 24 is a developing device, and 25 is a transfer charger.

In this embodiment, for example, there are three sensors la.

lb and lc are provided. That is, sensor 1a is an AE sensor that measures the amount of light incident on the photoreceptor drum, sensor 1b is a surface potential sensor that measures the surface potential of the photoreceptor drum, and sensor 1c measures the density of the image copied on paper. This is a concentration meter for

Although not shown in Figure N3, three types of actuators are provided. That is, the main charging volume VRI is used to change the main charging voltage of the photoreceptor drum, and the lamp volume A is used to control the light amount of the halogen lamp.
Three volumes are provided as actuators: VR and a transfer volume VR2 for controlling the transfer voltage between the photosensitive drum and copy paper.

By the way, the target machine shown in Fig. 3 can be viewed from a physical perspective, and the target machine can be expressed at the physical level as a combination of multiple elements, and the behavior and attributes of each element and the connection relationship between each element can be expressed using parameters. When expressed qualitatively using this method, it is as shown in Table 1. The expression format shown in Table 1 will be referred to as a "substantive model."

Furthermore, the representation shown in FIG. 4 in which the entity model is abstracted and expressed as a connection tree of each parameter will be referred to as a "mathematical model."

Then, by combining the "substantive model" and the "mathematical model",
We will call it the "target model". The "target model" is qualitative data common to image forming apparatuses that is also utilized for failure repair, which will be described later.

(The following is a blank space) Table 1 "Substantive Model" The contents of the substantive model and the mathematical model as qualitative data are stored in the target model storage unit 14.

The target model storage unit 14 also stores information regarding predetermined parameters among the parameters included in the real model.
For example, reference value data measured at the time of factory shipment is stored. This reference value data is characteristic data specific to this image forming apparatus.

For example, in this machine, as shown in FIG.
Reference value data specifying the normal and high ranges is stored.

In this embodiment, the above-mentioned reference value data can be updated in response to sensing data during subsequent failure diagnosis and failure repair processes, changes in the operating state of the machine, and the like.

Furthermore, the target model storage unit 14 stores evaluation function knowledge as an example of fault diagnosis knowledge, which is a standard for determining whether or not the target machine is operating normally, based on the converted symbol. ing.

Note that the evaluation function knowledge, in other words, the failure diagnosis knowledge, may be specific to the target device, or may not be specific and may be common to a wide range of image forming apparatuses.

The evaluation function knowledge includes the following knowledge: image density O1-normal, fogging degree O1-normal, separation performance S, <normal here, 0. ．． 0.・, S, or if the above conditions are not met, it means that the target machine is not operating normally.

Now, consider the case where the digitized sensor information of the target machine during normal operation is the following values: AE sensor value X-30 Surface potential sensor value V, -300 Densitometer value 01-7 Also, optical density Densitometer value O1 when using D-0 blank original - fogging degree 0.7, surface potential sensor value V with the halogen lamp turned off
, -dark potential V7, and their values are, respectively, fogging degree O5·-50 dark potential V, l-700.

Note that these fogging degrees are 0. The measurement of ・and the dark potential V, may be performed manually, or may be measured automatically by a sensor under certain conditions, for example, each time the target machine is turned on, or each time before copying starts. It may be programmed to do so. In this embodiment, the latter is adopted.

The six values X, V6, O, , O5vo obtained by the AE sensor 1 a s surface potential sensor 1 b and the densitometer 10 are each converted into symbols in a digital signal/symbol converter 11 .

The conversion is performed for each sensor la, lb or I as described above.
The digital value given from C is stored in the target model storage unit 1.
This is done by comparing it with reference value data as feature data stored in 4, and converting it into one of three types of symbols: normal, high, or low.

In this example, each parameter is symbolized as follows.

X-High■, -Low 0, -Low■4-Normal In the fault diagnosis unit 12, each of these symbolized parameters is used for functional evaluation as an example of fault diagnosis knowledge stored in the target model storage unit 14. compared to knowledge. As a result, the image density was O.

is not normal, it is determined that there is a failure, and the failure symptom is determined to be "image density is too low (0.-low)". Next, the failure is diagnosed, that is, the cause of the failure is inferred using ``ro'' as the failure symptom.

Fault diagnosis is first performed in the fault simulation unit 13 using the mathematical model shown in FIG. 4, and a parameter that may cause O1=low is searched for.

In the mathematical model shown in FIG. 4, parameters that may cause a decrease in O are shown in FIG. 6. In Figure 6, the parameters marked with an upward arrow or a downward arrow are parameters that may cause parameter O1 = low. If that parameter decreases, it causes O8-low.

Next, each parameter ζ,D that can cause O,-mouth was explored in the mathematical model.

v, 7o,v,,v,,v,,x,β,H.

Regarding D, the failure diagnosis unit 12 detects the cause of the parameter change.

This detection is performed based on the entity model shown in Table 1, and in this embodiment, the following failure cause candidates are inferred.

That is, (1) Defective low knee transfer transformer ζ - Low: → Deterioration of paper ■, = Defective high knee developing bias γ. = Low toner deterioration V, -Low, -Main charging voltage failure HL-High: → Incorrect halogen lamp setting D -Low:
→The original is thin. Among the parameters, β is the sensitivity of the photoreceptor and is excluded because it does not increase.

D, , V, and X are also excluded since they are represented by other parameters.

Then, in response to the above inference made in the fault diagnosis section 12, a fault state simulation is performed in the fault simulation section 13.

Simulating a fault state means inferring the state of the target machine when the inferred fault occurs. More specifically, it is assumed that the cause of 0-low, that is, the cause of failure is, for example, a defective transfer transformer, and Vl-low is set for a model in a normal state. Then, the influence on each parameter in that state is examined using a mathematical model. - If set to low, 0. -low and S, -low, and all other parameters are normal, so this contradicts the X-high and V,-low obtained from the sensor. Therefore, the result is that the inference regarding the cause of the failure is incorrect.

Similarly, ζ-rho is set on the normal state mathematical model and the result is compared with the symbols obtained from the sensor. In this case as well, on the mathematical model, for X-normal,
Since the symbol from the sensor is X-high, there is a contradiction and the inference of the cause of the failure is determined to be incorrect.

In this way, a simulation of the failure state is performed for all failure cause candidates, and it is confirmed whether or not the inference of the failure cause is correct.

As a result, in this example, when the cause of the failure is determined to be "incorrect halogen lamp settings (HL-high)", a result that matches the actual condition of the target machine can be obtained, and other causes of the failure can be determined. It is concluded that all candidates are inconsistent with the actual state of the device.

Therefore, it can be concluded that the cause of the failure in this case is improper setting of the halogen lamp. Table 2 shows the status of each parameter of the target machine at that time.

Table 2: Incorrect halogen setting When the states of the parameters shown in Table 2 are traced on a mathematical model, FIG. 7 is obtained. In FIG. 7, the downward arrow attached to the right side of each parameter indicates low, the upward arrow indicates high, and N indicates normal.

Next, we will explain the reasoning behind the restoration plan.

As a result of fault determination, "Image density is too low (0°-low)"
” or as a failure symptom, the goal of repair is to
0. The goal is to increase the

Therefore, from the relationship in the mathematical model shown in Figure 4, it is possible to increase the repair target O by increasing D, increasing ■1, or increasing ζ. It is inferred.

Next, when inference is made with the goal of increasing D, ■
Raise , or lower ■, or γ.

Either rise or get a conclusion. in this way,
By repeating the inference based on the mathematical model,
Candidates for repair operations can be obtained on a mathematical model. The results obtained are shown in Table 3.

(Margins below) Table 3 By the way, among the repair candidates obtained based on mathematical models, there are some that can be realized and some that cannot be realized. For example, D: The optical density of the original cannot be changed, and β: The sensitivity of the photoreceptor is also difficult to change.

γ. : Toner sensitivity cannot be changed, ζ, paper sensitivity is also unchangeable.

Also, in this specific example, ■,: Bias voltage It is also impossible to change because there is no actuator.

Of course, by adding an actuator, ■,
can be made changeable.

Furthermore, X: Logarithm of the amount of light reflected from the original, ■: The surface potential of the drum after exposure, and the toner density on the double drum cannot be changed per se; other parameters cannot be changed indirectly. Since it can be changed, it is excluded from repair candidates.

Although not directly related to this specific example, the amplitude of the separation AC voltage can also be changed by adding an actuator.

Depending on the above, in this specific example, as a repair candidate, Vl: Transfer voltage Vゎ: Surface potential after main charging Logarithm of H5/halogen lamp output light intensity It can be taken away.

On the other hand, the target model storage unit 14 stores in advance the following considerations as repair plan knowledge. That is, (a) Increase the control voltage of the transfer transformer to increase V. (b) Decrease the control voltage of the transfer transformer to decrease V. (c) Increase the control voltage of the lifetime charging transformer to increase V. (d) Decrease V, lower the control voltage of the lifetime charging transformer (e) Increase H+ - shift the halogen lamp control signal to the high voltage side (f) Decrease HL - lower the halogen lamp control signal Shift to voltage side.

It is. The repair plan knowledge stored in the target model storage unit 14 is characteristic data specific to this device. By applying the repair plan knowledge to the repair candidates obtained based on the mathematical model, as a repair operation to increase Ol, (a) increase the control voltage of the transfer transformer to increase V (C) There are three ways to increase Vo: increase the control voltage of the charging transformer (f) decrease HL - shift the halogen lamp control signal to the lower voltage side.

If you just want to increase the image density O1, these 3
Repair is possible by performing any of the methods.

However, the target machine may be affected by various side effects by increasing the image density 08. Therefore, in this embodiment, as explained below, the inference of secondary effects is performed based on a mathematical model.

When the three repair plans derived in the inference of the side effect repair plan are developed on a mathematical model, Figures 8 to 13 are obtained. In other words, (a) Figures 8 and 9 show the case where V is increased (Figure 9 shows Os when D-0 is expressed on the mathematical model), and (c) Vfi is increased. When raised, Figures 10 and 11 (Figure 11 shows 05 when D = 0, or are expressed on a mathematical model), (
f) When H4 is lowered, see Figures 12 and 13 (
In FIG. 13, 05 is expressed on a mathematical model when D=O.

Then, when a functional evaluation is performed based on the mathematical model, the following state is inferred.

That is, (1) When V is increased (Figures 8 and 9) (a)
Output image density increases.

(b) When D-0, 0.・〉It may be normal.

In other words, fogging may occur.

(c) S becomes > normal, and there is a possibility that a separation failure will occur.

(2) When V is increased (Figures 10 and 11) (a) Output image density increases.

(b) When D=O, ○, > normal, and there is a possibility that fogging may occur.

(3) When HL is lowered (FIGS. 12 and 13) (a) Only the output image density increases, and there are no other side effects.

Therefore, the repair planning unit 15 selects a repair plan that has the least side effects, that is, a repair plan that lowers the HL. This repair plan is consistent with the operation to eliminate the cause of the failure found in the failure diagnosis.

In other words, looking at it from a different perspective, inferring the cause of a failure in fault diagnosis involves tracing the actual state of the device when it fails on a mathematical model and understanding the state of each component when the device fails. In contrast to estimating the cause of a failure, estimating a repair plan is based on the premise that the device is normal rather than in a failure state, tracing the condition of the device on a mathematical model, and based on that. Recommends a restoration plan.

In the above-mentioned specific example, the same failure cause and repair plan were obtained both in the inference in the failure diagnosis and in the inference in the repair plan.

However, in some cases, the results obtained by the two methods may differ because inferences for fault diagnosis are based on devices in a faulty state, while inferences for repair plans are based on devices in a normal state. .

In such a case, if only those conclusions that do not contradict the conclusions obtained in the inference process of failure diagnosis are selected when inferring a repair plan, the inference process of the repair plan can be performed in a shorter time.

In the above case, if the repair plan of lowering the HL cannot be selected, for example if the AVR volume for shifting the halogen lamp control signal to the lower voltage side is already at the lower limit, then the secondary (2) ■, which has little impact. A restoration plan was selected to increase the

However, if a repair plan that increases Vo is selected, a side effect of the possibility of fogging is predicted, so in the mathematical model of FIG. 11, 0. Which parameter should be manipulated in order to lower . As a result, it is selected whether to raise HL, lower Vo, or lower (2), and a repair plan including prevention of fogging is carried out.

That is, as shown in FIG. 14, the reasoning for the repair operation is developed assuming side effects. In the inference development of repair operations as shown in Figure 14, (a) techniques that contradict the previous repair plan on the mathematical model are not selected (b) techniques with the least side effects are selected (C ) Unrolling is based on the knowledge that anything that forms a loop will stop unrolling at that point.

In FIG. 14, in the end, two repair plans remain: (1) a loop of V, ↑-H5↑→V, ↑, and (2) a loop of V, ↑→■, ↓→Vfi↑.

Now, suppose that when loop (1) is performed as a repair plan, the image density becomes an appropriate density, that is, O6 or normal. In such a case,■. and HL have been increased, so in the post-repair state where the image density O1 has returned to normal, the value of the surface potential measured by the sensor 1b changes to a much higher value than the value initially measured. There should be. However, since the repair operation was successful, the state of the parameter V after repair must be symbolized normally. Therefore, in such a case, when the repair is completed, the reference data for symbolizing the parameter V shown in FIG. 5 is changed based on the measured value measured by the sensor 1b,
For example, the data is rewritten to the data shown in FIG.

In this way, the reference data is updated as necessary after the repair work is completed.

In this embodiment, the above-mentioned (1) in FIG.
Specifically, when the main charging volume VRI is operated to raise the surface potential of the photoreceptor drum 21, and as a result, a rash occurs on the resulting copy, the lamp volume AVR is operated to increase the halogen The light intensity of the lamp is increased and the image density of the copy is diluted.

Then, while increasing the main charging volume VRI and lamp volume AVR alternately and appropriately, when the image density becomes normal, that is, when the parameter O becomes normal, it is obtained from the detection output of the densitometer, which is the sensor IC. When this occurs, the repair process is terminated.

Furthermore, if the above two repair plans are infeasible, a repair plan of increasing V in (3) above is selected, resulting in the secondary effects of fogging and poor separation. A fault diagnosis is performed based on one assumption, and a repair plan is selected.

Then, the selected repair plan is executed, and in the case of loop processing, it is determined that the plan has failed when the operation of the parameters on the loop reaches its limit.

In addition, in the case of this embodiment, as explained in the specific example, 0. It is determined that the repair is complete when it becomes normal.
In this state, the repair is stopped.

In the inference of the side effects described above, the three repair plans derived in the inference of the repair plan are sequentially developed on a mathematical model, and the side effects are collectively inferred for each of the three repair plans. ing.

Instead of this method of inferring side effects, the following processing may be performed.

That is, suppose that, for example, three repair plans are derived in the repair plan inference. In that case, take only one repair plan out of the three, simulate the side effects that may occur if the actuator means is actuated based on that repair plan, and It is determined whether the negative influence can be removed by actuating an actuator means other than the actuator means selected by the repair plan.

When it is determined that the side effects can be eliminated, the actuators selected by the repair plan are actually operated to carry out the repair, and the side effects are eliminated by activating other actuator means. It removes it.

As a result, there is no need to simulate the side effects based on the other two plans derived from the repair plan, and overall the repair operation time can be shortened.

In the above case, if for the first selected repair plan, a side effect is simulated and it is determined that the simulated side effect cannot be removed by actuating another actuator means. If it is done,
The first repair plan is abandoned and a second repair plan is taken up, and the side effects that may occur if the actuator means selected based on the second repair plan are actuated. simulating secondary effects, determining whether the simulated secondary effects can be removed by actuating an actuator means other than the actuator means; and when the secondary effects can be removed; , performs repair work based on the second repair plan.

In this way, if the first repair plan is extracted from among the multiple repair plans derived in the inference of the repair plan, the side effects in that case are inferred, and the side effects can be removed. Then, immediately execute the repair based on the first repair plan.

If that repair plan has too many side effects, it is abandoned, the next repair plan is selected, and the side effects in that case are simulated.

In such a case, it is preferable to select which repair plan first among the plurality of repair plans derived in the inference of the repair plan, taking into account the cause of the failure obtained in the failure diagnosis, for example.

In the above embodiments, the repair itself is severely limited due to the small number of actuator parameters, or the flexibility and possibilities of repair can be further improved by increasing the number of actuator parameters.

In the specific example explained above, if any repair work is successful, the state of the equipment after the success is determined to be normal, but it is It is preferable that the reference value data of each parameter (the reference values shown in FIG. 5) be updated and the parameters be symbolized based on the new reference value data.

Further, in the above-mentioned specific example, although the operating range of each actuator was not particularly mentioned, the target model storage unit 14
If the operating range data that sets the actuator's operating range is included in the characteristic data specific to the device stored in the device, the actuator can be operated when the output state of the actuator is within the stored operating range. When the output state of the actuator reaches the upper or lower limit of the stored operating range, it can be determined that the actuator cannot be operated, and this can be used to determine whether the repair work is correct or not.

Furthermore, in the above-mentioned specific example, a system that automatically performs self-diagnosis and self-repair based on a change in sensor output was introduced, but if the image forming apparatus is provided with a self-diagnosis mode setting key, etc. Self-diagnosis and/or self-repair may be performed only when the self-diagnosis mode setting key is operated.

In the above specific example, the system is completely autonomous, that is, the device itself automatically diagnoses whether there is a failure or not, and self-repairs if a failure occurs, without any operation by service personnel or users. I picked it up and explained it. However, in this invention, the sensor is removed from the configuration requirements, and a service person or the like measures functional status data at predetermined locations of the image forming apparatus, and the measured data is manually input to the apparatus. By doing so, it is possible to configure an image forming apparatus that can perform non-autonomous self-diagnosis and perform autonomous repair based on the self-diagnosis.

In addition, if you configure a system that only selects the actuator to repair a failure based on the results of a self-diagnosis performed by the device, but does not actually operate the actuator, and displays the actuator that should be operated, service can be improved. The image forming apparatus may include a non-autonomous repair system, in which a person only needs to operate the displayed actuator.

Of course, it is also possible to exclude the configuration requirements of the self-repair system and configure an image forming apparatus having only the self-diagnosis system.

That is, according to the present invention, (1) an image forming apparatus having a fully autonomous self-diagnosis and self-healing system; (2) an image forming apparatus having an autonomous self-diagnosis system and a non-autonomous self-healing system; (3) (4) an image forming device having a non-autonomous self-diagnosis system and a non-autonomous self-healing system; (4) an image forming device having a non-autonomous self-diagnosis system and an autonomous self-healing system; or (5) an image forming device having only an autonomous self-diagnosis system. The forming device can be configured as required.

In addition, in this invention, when inferring a repair plan,
In consideration of the adjustment range of the actuator, only actuators that are actually adjustable may be selected.

To explain more specifically, the actuator is, for example, A
In the case of VR, the lower limit of AVR is "0" and the upper limit is rlo
oJ, and the configuration is such that the AVH setting state can be detected as an integer value from 0 to 100. In addition, the lower limit value “0” and the upper limit value r1 of the AVR are stored in the target model storage unit 14.
Set 00J. Therefore, when the AVR is in an adjusted state, the adjusted state of the AVR is understood as integer value data ranging from 0 to 100 corresponding to the adjusted state.

The repair planning unit 15 uses integer value data from 0 to 100 obtained depending on the adjustment state of the AVR to
It is determined whether the AVR can be selected as the actuator for troubleshooting. That is, the lower limit value and upper limit value of the AVR stored in the target model storage unit 14 are compared with the current adjustment state value, and it is determined whether the AVR can be further operated toward the lower limit or toward the upper limit. It will be done.

Therefore, by adopting such a configuration for each of a plurality of actuators or any actuator among them, the inference result of the repair plan can be used as a combination of actuator means that can actually be operated. It has the advantage that it can be output and a practical repair plan can be inferred.

Note that the above explanation is just an example of how to set the operating range, and the operating range may be set using another method and compared with the actual state of the actuator.

In addition, the repair planning section 15 not only compares the set adjustable range of the actuator with the actual adjustment value, but also the failure diagnosis section 12 when performing failure diagnosis.
The set adjustable range of the actuator and the actual adjustment value may be compared and referred to.

<Effects of the Invention> According to the present invention, when the state of the image forming apparatus is abnormal, the presence or absence of a failure can be determined by simply determining the status data and inputting it from the data input means, and the cause of the failure can be determined. It is inferred. Therefore, a service person or the like can easily repair a malfunction in the image forming apparatus by selecting and operating the actuator means to eliminate the presumed cause of the malfunction.

As described above, according to the present invention, there is provided an image forming apparatus having a semi-automated self-diagnosis in which the cause of the failure can be diagnosed by simply inputting data when a failure is thought to have occurred, and a system capable of performing repairs based on the semi-automated self-diagnosis. can be provided.

Further, according to the present invention, since the cause of failure is determined based on qualitative data common to image forming apparatuses, the present invention has a self-diagnosis and repair system that can handle unknown failures that are not explicitly described. It can also be an image forming device.

Furthermore, the self-diagnosis and repair system according to the present invention can be commonly applied to many types of image forming apparatuses, rather than to a specific image forming apparatus, resulting in an inexpensive self-diagnosis and repair system. An imaging device having a diagnostic and repair system can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the system configuration of an embodiment of the present invention. FIG. 2 is a flowchart showing the operation of the control circuit in FIG. FIG. 3 is a diagram showing a schematic configuration of the present invention when used in a plain paper copying machine. FIG. 4 is a diagram representing a mathematical model of this embodiment. FIG. 5 is a diagram showing reference value data of each parameter necessary when each parameter is symbolized. FIGS. 6 and 7 are diagrams showing development for fault diagnosis on a mathematical model. FIGS. 8 to 13 are diagrams showing the development of the secondary influence inference on the mathematical model. FIG. 14 is a diagram showing operations when selecting a repair plan. FIG. 15 is a diagram showing updated reference value data. In the figure, la, lb, 1cm sensor, 6a. 6b, 6c...Actuator, 1o...System control circuit, 11...Digital signal/symbol converter, 12...Failure diagnosis unit, 13...Failure simulation unit, 14...Target model storage Part, 15...Repair planning part, 16... Symbol/digital signal conversion part,
shows.

Claims (1)

[Scope of Claims] 1. An image forming apparatus that embodies image data to generate a visible image, including a plurality of actuators that can change the functional state of the image forming apparatus and eliminate the cause of failure. A self-diagnosis and repair system for an apparatus including a means for expressing the image forming apparatus as a combination of a plurality of elements, characteristic data representing the characteristics of the image forming apparatus, behavior or attributes of each element, and information between each element. storage means in which qualitative data qualitatively representing the coupling relationship and fault diagnosis knowledge are stored; and adjustment range setting means in which a predetermined adjustment range is set for a predetermined actuator means among the plurality of actuator means. , an adjustment state output means for detecting and outputting the adjustment state of a predetermined actuator means among the plurality of actuator means, a data input means, and state data representing a functional state of the image forming apparatus being provided from the data input means. The image forming apparatus includes a failure determination means for determining whether the image forming apparatus is normal or abnormal based on the status data, characteristic data stored in the storage means, and failure diagnosis knowledge; is determined to be abnormal, the qualitative data and fault diagnosis knowledge stored in the storage means and the adjustment state of the actuator means given from the adjustment state output means and the adjustment of the actuator set in the adjustment range setting means A self-diagnosis and repair system for an image forming apparatus, comprising: a failure diagnosis means for inferring a cause of failure based on a comparison of ranges.