JPH0816075A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the reliability of a fan motor, and to reduce the noise of the device, by formulating an optimum control amount by using a fuzzy inference, from an uncertain variation facters (quantity of state) relating to the control of the device. CONSTITUTION:A CPU 101 is a main controller to control the whole body of this device, and its main functions are a suitability calculation function, an operation function, and a calculation function. The CPU 101 finds the inferring results of the regulations stored in a ROM 102, and calculates an operating amount depending on the inferring results. Depending on the load current value, the driving system power source voltage value, the temperature in the device, and the comparison result of those values, the optimum control values to the uncertain variation factors (the quantity of state) relating each other are calculated by using a fuzzy control, and by inputting them to a fan motor driver 110, an optimum fan motor rotating time in an image forming device, and an optimum dummy current value given to the dummy current control can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser beam printer having a cooling means for cooling the inside of a machine and a switching power supply.

[0002]

2. Description of the Related Art Conventionally, an engine controls a cooling means in accordance with an arbitrary state regardless of conditions such as an input voltage, an environmental temperature, a load current, a drive system power supply voltage, and an in-machine temperature. In the stabilization control of the output voltage generated from the switching power supply, input voltage, environmental temperature, load current,
The engine was operating according to an arbitrary state regardless of conditions such as the temperature inside the aircraft.

[0003]

The present invention has been made for the purpose of solving the above-mentioned problems, and has the following constitution as one means for solving the above-mentioned problems. That is,
In an image forming apparatus having a cooling means for cooling the inside of the machine and a switching power supply means, a means for generating a state quantity of a load current of a drive system, a means for generating a state quantity of the switching power supply voltage, and a state quantity of a temperature inside the machine. Means, an operation amount for controlling the driving time of the cooling means, a means for generating an operation amount for stabilizing control of the switching power supply means, the state quantity and the operation Rule means for relating the relationship with the quantity as a qualitative rule, and inference means for inferring the operation quantity based on the degree to which the state quantity belongs to a predetermined set according to the rule by the rule means, The driving time and cooling amount of the cooling unit and the voltage stabilization of the switching power supply unit in the first period are controlled based on the inferred value of the operation amount by the inference unit.

The rule means stores first fuzzy sets in which state quantities and operation quantities are expressed by membership functions, and rules in which state quantities and operation quantities are expressed in the form of fuzzy production rules. A second storage means for storing the state quantity based on the membership function of the state quantity stored in the first storage means. 1
Calculation means, second calculation means for obtaining the inference result of the rule stored in the second storage means based on the matching degree, and the operation amount based on the inference result of each rule obtained by each calculation means. And a third calculating means for calculating

In the above structure, in controlling the driving of the cooling means of the image forming apparatus and stabilizing the voltage of the switching power supply means, the state quantity of the load current of the drive system, the state quantity of the output voltage generated from the switching power supply means, and the on-board Fuzzy inference formulates an ambiguous relationship between the amount of operation of the temperature state amount and the amount of operation of the cooling unit and the amount of operation of the output voltage generated from the switching power supply unit to control the print paper conveyance start time. To function.

[0006]

However, in the above-mentioned conventional example, in the cooling fan, it is necessary to set a predetermined specified rotation time to a rotation time that enables reliable cooling in all states. Although the rotation time could be made smaller, the assumed rotation time was set assuming the worst case. Therefore, although the shorter time is actually sufficient, the fan was rotating until the predetermined time was reached.

Further, also in the current for stabilizing and controlling the output voltage derived from the switching power supply, it is necessary to set a predetermined specified current to a current that ensures the output voltage to be a specified value in all states. Even though the specified current can be made lower, the specified current was set assuming the worst case. Therefore, although the stabilization control current can be made smaller, the specified current is set assuming the worst case. In such a case, the power consumption of the switching power supply has become unnecessarily large.

Further, the method of formulating all the states and changing the specified rotation time and the specified current according to the states does not require calculating the optimum fan rotation time and the necessary stabilizing control current from all the states. However, there is a problem in that it is difficult to formulate the relationship between the fan rotation time in all states and the necessary stabilizing control current.

That is, when the number of state quantities that determine all the states is increased by trying to obtain the optimum fan rotation time and the necessary stabilizing control current, and the state quantities and the manipulated variables. When there is an ambiguous relationship between the fan rotation time and the stabilization control current, there is a problem that it is difficult to formulate the relationship between the state quantity and the operation quantity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an image forming apparatus (hereinafter referred to as an apparatus) according to an exemplary embodiment of the present invention. In the figure, a CPU 101 is a main control unit that controls the entire apparatus, and its main functions are a matching calculation function, a calculation function, and a calculation function described below.
That is, the matching calculation function is to calculate the matching degree of the detected state quantity based on the membership function of the state quantity stored in the ROM 102.

As the arithmetic function, the inference result of each rule stored in the ROM 102 is obtained by a predetermined arithmetic operation based on the calculated compatibility. The calculation function is to calculate the operation amount based on the inference result of each rule obtained.

Reference numeral 104 is a timer, and 105 is a counter, which are used for obtaining the detected state quantity, for example, the rate of change per unit of fixing device temperature. ROM
A storage unit 102 stores a membership function.
(A), a storage unit 102 (b) that stores rules expressed in the form of fuzzy production rules, and a storage unit 102 (c) that stores control programs and the like.

The RAM 103 is used as a work area when the CPU 101 performs fuzzy inference. FAN motor driver 110 is CPU1
From 01, the actual operation amount calculated by the fuzzy inference is received, and the output of the FAN motor ON signal and the dummy current value of the switching power supply unit are adjusted.

The FAN motor 111 controls the rotational drive of the FAN motor by fuzzy reasoning according to the FAN motor ON signal. The dummy current control circuit 100 (a) of the switching power supply output voltage generation unit controls the dummy current by fuzzy reasoning according to the dummy control signal from the CPU 101. What functions as a state quantity detection unit in this device is a current detection unit 100 that detects a drive system load.
(B), voltage detection means 100 for detecting the drive system power supply voltage
A switching power supply means 100 having (c) and the like, and a thermistor 109 which is a temperature detection means installed at a location most susceptible to thermal stress in the apparatus. The load current signal from the switching power supply means 100, the load power supply voltage signal, and the in-machine temperature signal from the thermistor 109 are input to the CPU 101 via the respective A / D converters 108.

In the fuzzy reasoning in the device according to the present embodiment, the current value of the current detecting means 100 (b) of the switching power supply means 100 and the voltage detecting means 100 (c) of the switching power supply means 100 are used as state quantities. Of the present voltage value, the difference between the target voltage and the present voltage, and the present temperature of the thermistor 109, which is the temperature detecting means, for example, (a) present in-machine temperature dt (b) present drive system power supply voltage dV (C) The current drive system load current dI is used.

As the operation amount, the FAN motor ON time control signal input to the FAN motor driver 110, the FAN motor air volume control signal, and the dummy current ON / input to the dummy current control circuit 100 (a) of the switching power supply means 100. Of the OFF signal and the dummy current value variable signal, (a) the signal Tf for controlling the FAN motor ON time, and (b) the signal Id for variably controlling the dummy current value are used.

FIGS. 3 and 4 show the membership functions of these sets. 3 (a) is a membership function of load current, FIG. 3 (b) is a membership function of in-machine temperature, FIG. 3 (c) is a membership function of drive system power supply voltage, and FIG. 4 (a) is The membership function of the FAN motor on-time control signal Tf input to the FAN motor driver, FIG.
The membership function of the signal Id which controls the current value given to 0 (a) is shown.

As is apparent from FIG. 3, fuzzy signals for controlling load current, drive system power supply voltage, in-machine temperature, FAN motor ON time control input to the FAN motor driver, and current value given to the dummy current control means. There are three sets each.

For example, in FIG. 3A, the load current of 3
For membership functions, the fuzzy label is
“DIL”, “dIM”, and “dIH” are attached, respectively. DIL: Membership function representing “small load current” dIM: Membership function representing “medium load current” dIH: “ It is a membership function that represents “the load current is large”.

The degree of belonging to each set is "0"
Takes any value from 1 to "1". For example, in FIG.
In (a), when the load current is 1.25 A, the degree of belonging to the fuzzy set with the fuzzy label dIM,
That is, the matching degree is “1.0”, the degree belonging to dIL is “0.2”, and the degree belonging to dIH is “0.
2 ".

Further, the FAN motor ON control signal input to the FAN motor driver 110 and the signal for controlling the dummy current value to the dummy current control means are determined by, for example, the following <Rule 1> and Use the fuzzy production rule of <Rule 9>.

That is, <Rule 1> IF (dV = dVL AND dI = d
IL) THEN Tf = TfL, Id = IdL <Rule 9> IF (dV = dVH AND dI = d
IH) THEN Tf = TfH, Id = IdL where dV = driving system power supply voltage, dI = load current, dt =
Machine temperature, Tf = FAN input to FAN motor driver
AN motor ON time control signal, Id = signal for controlling the dummy current value given to the dummy current control means. Here, all the fuzzy production rules in this embodiment are shown in FIG.

Next, in the apparatus according to this embodiment, the FAN
A method for determining the FAN motor on-time control signal input to the motor driver and the signal for controlling the dummy current value given to the dummy current control means based on the inference methods of <Rule 1> and <Rule 9> will be described.

First, inferring according to <Rule 1> and <Rule 9>, as shown in FIG. 5, for the drive system power supply voltage value α (see FIG. 5A), the drive system power supply voltage value is Is included in the set of dVL at the degree of the membership function μα of, and for the load current value β (see FIG. 5B), included in the set of dIL at the degree of the membership function μβ of the load current value, For the rate of change γ of the in-machine temperature (Fig. 5
(See (c)), which is included in the set of dtM in the degree of μγ by the membership function of the rate of change of the in-machine temperature.

Then, as the degree to which the antecedent part (IF part) of <rule 1> is satisfied with the obtained minimum values of μα, μβ and μγ, the on-time control signal input to the FAN motor driver at that value Slice the membership function (in this case, TfL) of Similarly, the membership function (in this case, IdL) of the signal for controlling the dummy current value given to the dummy current control means is sliced. The result is a trapezoid shown by S1 and S2 (hatched portion) in FIGS. 5 (d) and 5 (e). Similarly, when inferred according to <Rule 9>, the calculation result becomes a trapezoid shown by sets T1 and T2 (hatched portions) shown in FIGS. 5 (i) and 5 (j).

Next, the inference result by each rule thus obtained, that is, the sets S1 and T1 are combined, and the sets S2 and T2 are combined in the same manner. The combined result is the sets U1 and U2 (hatched portions) shown in FIGS. 5 (k) and (l), and the centers of gravity of the sets U1 and U2 (points P1 and P2) are shown.
Is calculated to obtain the FAN motor ON time control signal Tf input to the FAN motor driver corresponding to the point P1 and the signal Id for controlling the dummy current value given to the dummy current control means.

As described above, the load current value, the drive system power supply voltage value, and the in-machine temperature are directly detected, and the FAN is determined based on them.
The drive control of the motor and the determination of the dummy current value given to the dummy current control means are performed by using fuzzy control.

As described above, according to this embodiment,
For the load current value, drive system power supply voltage value, in-machine temperature, mutual comparison result, and mutual ambiguous fluctuation factors (state quantities), fuzzy control is used to calculate the optimum control amount, Thereby, the control of the control signal input to the FAN motor driver and the control of the dummy current value given to the dummy current control means are performed, so that the optimum FAN motor rotation time in the image forming apparatus and the optimum dummy current for the dummy current control are provided. There is an effect that the value can be controlled.

In the above-mentioned conventional example, fuzzy production rules, membership functions, control programs, etc. are stored in the ROM and calculations are performed using the RAM. However, the operation amount corresponding to the input of the state amount is calculated in advance. Alternatively, control may be performed using a ROM that outputs this value. By doing so, the processing speed can be improved.

Furthermore, the number of state quantities is not limited to three,
A larger number of state quantities may be combined. Further, the above-mentioned fuzzy inference algorithm is an example, and it is acceptable to modify it. For example, instead of taking the center of gravity of the area when combining a plurality of rules, the value on the horizontal axis with respect to the maximum value on the vertical axis may be used as the inference result. Furthermore, the number and contents of fuzzy production rules can be modified based on experience.

(Other Embodiments) In the second embodiment, as the state quantity for fuzzy control, instead of the in-machine temperature dt used in the first embodiment, the rate of change of the in-machine temperature per unit time is changed. dT is used. FIG. 6 shows all fuzzy production rules according to the second embodiment. In FIG. 6, dTL, dTM, and dTH represent dTL: “the rate of change of in-machine temperature is small”, respectively. Fuzzy set dTM: A fuzzy set representing "the rate of change of the in-machine temperature is medium" dTH: A fuzzy set representing "the rate of change of the in-machine temperature is large". The method for obtaining the optimum on-time control signal input to the FAN motor driver and the signal for controlling the optimum dummy current supplied to the dummy current control means is the same as that in the first embodiment, and therefore will be described here. Is omitted.

[0031]

As described above, according to the present invention, the optimum control amount is clearly formulated by fuzzy inference from the ambiguous variable factor (state amount) related to the control of the image forming apparatus. (1) An accurate FAN driving time can be obtained in consideration of complicated factors. (2) It is possible to control the dummy current supplied to the appropriate dummy current control means in consideration of complicated factors. (3) Since the control amount is determined based on a plurality of parameters, even if there is an error in a part of the input data, it is possible to prevent a significant error in the control amount. (4) FA can be driven by optimal FAN motor drive.
It is possible to improve the reliability of the N motor and reduce the noise of the device. (5) By performing optimum dummy current control, it is possible to reduce power consumption and simplify the configuration of the switching power supply means.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing all fuzzy production rules in the first embodiment of the present invention.

FIG. 3 is a diagram showing a membership function of a state quantity in the first embodiment of the present invention.

FIG. 4 is a diagram showing a membership function of an operation amount in the first embodiment of the present invention.

FIG. 5 shows the FA in the first embodiment of the present invention.
It is a figure explaining the method of determining an N motor on control signal and a dummy current value.

FIG. 6 is a diagram showing all fuzzy production rules in the second embodiment of the present invention.

[Explanation of symbols]

 100 switching power supply means 101 CPU 102 ROM 103 RAM 110 FAN motor driver

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Nakahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Yasumasa Rikoda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Takazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takashi Seiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Within

Claims (3)

[Claims] 1. An image forming apparatus having a cooling means for cooling the interior of a machine and a switching power supply, and a means for generating a state quantity of a load current of a drive system and a state quantity of an output voltage generated by the switching power supply means. Means, means for generating a state quantity of the temperature inside the machine, means for generating a manipulated variable when controlling the driving time and the cooling amount of the cooling means, and stabilizing control of the output voltage generated from the switching power supply means. The degree of belonging to a predetermined set according to a rule by the means for generating a manipulated variable when performing, a rule means for relating the relationship between the state quantity and the manipulated quantity as a qualitative rule, and a rule by the rule means Based on the inference means for inferring the operation amount, the driving time and the cooling amount of the cooling means and the switching amount based on the inference value of the operation amount by the inference means. An image forming apparatus characterized by controlling voltage stabilization of a power supply unit. 2. The image forming apparatus according to claim 1,
The rule means stores first fuzzy sets in which a state quantity and an operation quantity are respectively expressed by a membership function, and a rule in which a state quantity and an operation quantity are expressed in a fuzzy production rule. A second calculation means, wherein the inference means calculates, based on the membership function of the state quantity stored in the first storage means, the goodness of fit, which is the degree to which the state quantity belongs to a predetermined set. Means, and second calculation means for obtaining the inference result of the rule stored in the second storage means based on the matching degree, and the operation amount is calculated based on the inference result of each rule obtained by each calculation means. An image forming apparatus, comprising: 3. The image forming apparatus according to claim 1,
It has a cooling means for cooling the inside of the machine and a switching power supply means, and the state quantity at this time is at least the load current of the drive system, the drive system voltage power supply, the power consumption, the inside temperature, and the change rate of the inside temperature per unit time. One or a combination thereof, and the operation amount is at least one of a driving time and a cooling amount of the cooling means, a voltage and a current for stabilizing and controlling the switching power supply means, or a combination thereof. Image forming apparatus.