JPH0830165A - Image forming device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To solve the problems of reduction of the first print time and wasteful power consumption related to the scanner motor on / off control and the fixing device on / off (standby) control. [Structure] A unit for generating a state quantity of the degree of warming of a fixing unit 109 of a fixing unit, a unit for generating a state quantity of the number of prints per unit time, and a rotation number of a scanner motor held at a rotation number capable of immediate printing. The means for generating the operation amount for the time to be kept, the means for generating the operation amount for the time to keep the temperature of the fixing device at a temperature at which printing can be performed immediately, and the relationship between the state amount and the operation amount as qualitative rules. Based on the relating rule means and the degree to which the state quantity belongs to a predetermined set,
An inference means for inferring the operation amount is provided. Then, based on the inference of the operation amount, the time for which the number of rotations of the scanner motor is held at the number of rotations for which immediate printing is possible, and the time for which the temperature of the fixing device is maintained at the temperature for which immediate printing is possible are 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 laser scanning means and a fixing means.

[0002]

2. Description of the Related Art In an image forming apparatus having a scanner motor for scanning a laser and a fixing device for applying heat and pressure to fix toner on a print sheet, the scanner motor is operated after a predetermined time has passed after printing. It was turned off and the fixing device was turned off or at the standby temperature.

[0003]

However, in the above-mentioned conventional example, the scanner motor is turned off after the stipulated time has passed after printing and the fixing device is turned off or set to the standby temperature regardless of the frequency of use of the apparatus. There is a problem that the first print time is reduced because the time is specified short when the device is frequently used, and wasteful power consumption is caused when the time is specified long when the device is not used frequently. did.

Further, all the states are formulated and the time for keeping the number of rotations of the scanner motor at the number of revolutions at which printing can be performed immediately and the time for keeping the temperature of the fixing device at the temperature at which printing is possible, depending on the state. The method of changing the setting is to calculate the time to keep the number of rotations of the scanner motor at the number of rotations that can be printed immediately and the time to keep the temperature of the fixing device at the temperature that can be printed immediately from all states. That is, it is difficult to formulate all the conditions and the time to keep the number of rotations of the scanner motor at the number of rotations that can be printed immediately and the time to keep the temperature of the fixing device at the temperature that can be printed immediately. There's a problem.

In other words, by trying to find the time for keeping the rotation speed of the scanner motor at the rotation speed at which printing can be performed immediately and the time for keeping the temperature of the fixing device at the temperature at which printing can be performed immediately, When the number of state variables that determine the state of the printer becomes large, or when the state motor and the rotation amount of the scanner motor, which is the operation amount, are held at the number of rotations that can be printed immediately, and the temperature of the fixing device is changed immediately. When there is an ambiguous relationship with the time for which the printable temperature is maintained, there is a problem that it is difficult to formulate the relationship between the state quantity and the operation quantity.

[0006]

The present invention has been made for the purpose of solving the above-mentioned problems, and has the following structure as one means for solving the above-mentioned problems. That is, in the image forming apparatus having the scanner motor for scanning the laser and the fixing device for applying heat and pressure for fixing the toner on the print paper, the state quantity of the fixing device of the fixing means is generated. Means, a means for generating a state quantity of the number of prints per unit time, a means for generating an operation amount of time for keeping the rotation speed of the scanner motor at a rotation speed capable of immediate printing, and a temperature of the fixing device. Means for generating an operation amount of time for keeping the temperature at which printing is possible immediately, rule means for relating the relationship between the state quantity and the operation quantity as a qualitative rule, and the state quantity according to the rule by the rule means. And an inference unit that infers the operation amount based on the degree to which the operation amount belongs to a predetermined set. Time and to retain lint possible speed
Controls the time to keep the temperature of the fixing device at a temperature at which printing is possible immediately.

The rule means includes a first storage means for storing a fuzzy set in which a state quantity and an operation quantity are respectively expressed by a membership function, and a rule in which the state quantity and the operation quantity are expressed in the form of a fuzzy production rule. A second storage means for storing the first quantity, wherein the inference means calculates the degree to which the state quantity belongs to a predetermined set based on the membership function of the state quantity stored in the first storage means. Means and a second calculating means for obtaining the inference result of the regulation stored in the second storage means based on the conformity degree, and an operation amount based on the inference result of each regulation obtained by each calculating means. The third calculation means for performing the calculation is provided.

In the above structure, the control of the time for which the number of rotations of the scanner motor of the image forming apparatus is set to a value at which printing can be performed immediately and the time for which the temperature of the fixing device is maintained at a temperature at which printing can be performed immediately are controlled. , The state quantity of the fixing device warming up, the state quantity of the number of prints per unit time, the operation amount of time to keep the number of rotations of the scanner motor at the number of rotations ready for immediate printing, and the temperature of the fixing device. The fuzzy inference formulas an ambiguous relationship between the operation amount of time to keep the temperature at which printing is possible immediately, and the control of time to keep the number of rotations of the scanner motor at the number of rotations at which printing is possible immediately. It functions to control the time to keep the temperature of the fixing device at a temperature at which printing can be performed immediately.

[0009]

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 fitness calculating function is to calculate the fitness of the detected state quantity based on the membership function of the state quantity stored in the ROM 102. Further, as the calculation function, the inference result of each rule stored in the R0M102 is obtained by a predetermined calculation based on the calculated conformance. The calculation function is to calculate the operation amount based on the inference result of each rule obtained.

Reference numeral 104 denotes a timer, and 105 denotes a counter, which are used for obtaining the detected state quantity, for example, the rate of change of the fixing device temperature per unit time.

The ROM 102 is also a storage unit 102 (a) for storing membership functions and a storage unit 1 for storing rules expressed in the form of fuzzy production rules.
02 (b), and a storage unit (c) for storing a control program and the like.

The RAM 103 is also used as a work area when the CPU 101 performs fuzzy inference. The polygon motor driver 113 is the CPU 10
From 1, the actual operation amount calculated by the fuzzy inference is received, and the polygon motor ON time control signal is output.
The polygon motor 112 (a) is controlled by fuzzy reasoning about the time for keeping the number of rotations at which printing is possible immediately, according to the polygon motor ON time control signal. Further, the heater driver 107 receives an actual operation amount calculated by fuzzy inference from the CPU 101 and outputs a heater on time control signal. The heater 109 (a) is controlled by fuzzy reasoning for the time to keep the temperature at which printing is possible immediately, according to the heater ON time control signal. What functions as a state quantity detection unit in this device is the heater 109 (a) that is a heat source, and the thermistor 10 that detects the heater temperature.
Fixing unit 109 having 9 (b) and the like, polygon mirror 112 (a) for scanning semiconductor laser light as a light source
And a scanning unit 112 having the same.

Output signals that enable fixing and scanning by the fixing means 109 and scanning means 112 are heater driver 107 and polygon motor driver 11 respectively.
3 is input to the CPU 101. For the fuzzy control in the apparatus according to the present embodiment, the rate of change in detected temperature per unit time dT and the number of prints per unit time are used as state quantities. The polygon motor on-time control signal input to the polygon motor driver 113 and the heater on-time control signal input to the heater driver 117 are used as the operation amount.

FIGS. 3 and 4 show membership functions of these sets. 3A is a membership function of the rate of change dT of the detected temperature per unit time, FIG. 3B is a membership function of the number of printed sheets dP per unit time, and FIG. 4A is a polygon motor. A polygon motor on-time control signal membership function input to the driver 113 is shown, and FIG. 4B shows a heater-on time control signal membership function input to the heater driver 117. As is clear from FIGS. 3 and 4, the rate of change in detected temperature per unit time dT, the number of printed sheets per unit time dP, and the polygon motor on-time control signal T input to the polygon motor driver 113.
m, the fuzzy set of the heater on-time control signal Th input to the heater driver 117 has three membership functions. For example, in FIG. 3A, the fuzzy label is "dTL" for three membership functions of the change rate dT of the detected temperature per unit time.
"DTM" and "dTH" are attached, respectively. DTL: Membership function representing "the rate of change dT of the detected temperature per unit time is small" dTM: "The rate of change dT of the detected temperature per unit time is Memberup function representing "medium" dTH: A memberup function representing "the rate of change dT in detected temperature per unit time 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 rate of change of the detected temperature per unit time is moderate, the degree of belonging to the fuzzy set with the fuzzy label dTM, that is, the degree of conformity is "1.0" and the degree of belonging to dTL. Is "0.2", and the degree of belonging to dTH is "0.2".

The determination of the polygon motor on-time control signal input to the polygon motor driver 113 and the determination of the heater on-time control signal input to the heater driver 117 are performed, for example, in the following <rule 1> and <rule>. Use the fuzzy production rule of 9>.

That is, <Rule 1> IF (dT = dTL AND dP = d
PL) THEN Tm = TMm, Th = ThL <Rule 9> IF (dT = dTH AND dP = d
PH) THEN Tm = TmH, Th = ThH, where dT = rate of change in fixing unit temperature per unit time, dP = number of prints per unit time, Tm = on-time control signal input to polygon motor driver, T
h = ON time control signal input to the heater driver. Here, all the fuzzy production rules in this embodiment are shown in FIG.

Next, in the apparatus according to the present embodiment, the on-time control signal input to the sheet feeding solenoid driver and the signal for controlling the energy to be applied to the fixing means are inferred according to <rule 1> and <rule 9>. A method of making a decision based on is explained.

First, inferring according to <Rule 1> and <Rule 9>, as shown in FIG. 5, for the rate of change α of the detected temperature per unit (see FIG. 5A), the detected temperature Membership function μα of change rate per unit time of
Is included in the set of dTL and is included in the set of dPL in the degree of the membership function μβ of the number of prints per unit time for the number of prints β per unit time (see FIG. 5B). . And the calculated μα
And μβ, and the minimum value is the degree to which the antecedent part (IF part) of <Rule 1> is satisfied. With that value, the membership function of the on-time control signal input to the polygon motor driver ( In this case, TmM) is sliced. Similarly, the membership function (ThL in this case) of the on-time control signal input to the heater driver is sliced. The result is a trapezoid shown by S1 and S2 (hatched portion) in FIGS. 5 (c) and 5 (d). 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 (g) and 5 (h).

Next, the inference results according to the rules thus obtained, that is, the sets S1 and T1 are combined, and similarly, the sets S2 and T2 are combined. The combined result is the sets U1 and U2 (hatched portions) shown in FIGS. 5 (i) and 5 (j), and the centers of gravity of the sets U1 and U2 (points P1 and P2) are shown.
To obtain the polygon motor on-time control signal Tm input to the polygon motor driver corresponding to the point P1,
And a heater on-time control signal Th to be input to the heater driver.

As described above, the rate of change of the detected temperature per unit time and the number of prints per unit time are directly detected, and based on them, the polygon motor on time input to the polygon motor driver and the heater driver input. The heater on time is determined by using fuzzy control.
As described above, according to the present embodiment, the rate of change in the detected temperature per unit time, the number of prints per unit time, the result of comparison between these, and the ambiguous variation factors (state quantities) related to each other. In contrast, the fuzzy control is used to calculate the optimum control amount, and the control signal input to the polygon motor driver and the control signal input to the heater driver are controlled by the control amount. Depending on the frequency of use of the device, the first print time can be shortened when the frequency is high, and the scanner motor and the fixing device are not wastefully driven when the frequency is low, reducing power consumption. The effect is that it can be achieved.

In the above-mentioned conventional example, fuzzy production rules, membership functions, control programs, etc. are stored in the ROM and the RAM is used for the calculation.
The operation amount corresponding to the input of the state amount may be calculated in advance, and the control may be performed using the 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, and a larger number of state quantities may be combined. Further, the above fuzzy reasoning algorithm is an example, and it may be modified. For example, instead of taking the center of gravity of the area when a plurality of regulations are combined, 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) FIG. 6 shows a fuzzy production rule of the second embodiment. In the first embodiment, since the number of fuzzy production rules is large, fine control can be performed, but the memory requirement becomes large. Therefore, in the second embodiment, the memory capacity is reduced so that rules are connected as smoothly as possible.

In the defuzzification method, the value on the horizontal axis relative to the maximum value on the vertical axis may be used as the inference result in addition to the centroid method. Further, the number and contents of fuzzy production rules can be modified based on experience.

[0025]

As described above, according to the present invention,
An accurate scanner motor that takes complex factors into consideration by clearly formulating the relationship between the frequency of use of the device and the ambiguous state amount and operation amount related to the time to keep the device ready for printing by fuzzy reasoning. It was possible to control the time of keeping the number of rotations of the printer at the number of rotations at which printing is possible immediately, and the time of keeping the temperature of the fixing device at the temperature at which printing is possible immediately. As a result, depending on the frequency of use of the device, the fast print time can be shortened when the frequency is high, and the scanner motor and the fixing device are not wastefully driven when the frequency is low, reducing power consumption. An image forming apparatus capable of achieving the above is obtained.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a fuzzy production rule table according to the embodiment.

FIG. 3 is a diagram showing a membership function of a state quantity according to an embodiment.

FIG. 4 is a diagram showing a membership function of an operation amount according to the embodiment.

FIG. 5 is a diagram showing a method of determining a polygon motor on-time control signal and a heater on-time control signal according to the embodiment.

FIG. 6 is a diagram showing a fuzzy production rule table according to another embodiment.

[Explanation of symbols]

 101 CPU 102 ROM 103 RAM 104 Timer 105 Counter 106 Paper Size Sensor 107 Heater Driver 108 A / D Converter 109 Fixer 110 Paper Feed Solenoid Driver 111 Paper Feed Solenoid 112 Scanner Unit 113 Polygon Motor Driver

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

Claims (2)

[Claims] 1. An image forming apparatus having a scanner motor for scanning a laser and a fixing unit for fixing toner to a cut sheet, and a unit for generating a state quantity of a warming state of a fixing unit of the fixing unit. , A unit for generating a state quantity of the number of prints per unit time, a unit for generating an operation amount of time for keeping the number of rotations of the scanner motor at the number of rotations ready for printing, and a temperature of the fixing device for immediate printing According to a rule by the rule means for relating the relationship between the state quantity and the manipulated variable as a qualitative rule, means for generating a manipulated variable for keeping the temperature possible, and the state quantity is predetermined. And an inference means for inferring the operation amount on the basis of the degree of belonging to the set, and the rotation speed of the scanner motor can be immediately printed based on the inference of the operation amount by the inference means. And the time to keep the rotation speed
An image forming apparatus characterized by controlling the time for which the temperature of a fixing device is kept at a temperature at which printing can be performed immediately. 2. The image forming apparatus according to claim 1,
The rule means stores a first memory state quantity that stores a fuzzy set in which a state quantity and an operation quantity are expressed by membership functions, and a rule that expresses the state quantity and the operation quantity in the form of a fuzzy production rule. A second memory state quantity, wherein the inference means calculates a goodness of fit, which is a degree to which the state quantity belongs to a predetermined set, based on a membership function of the state quantity stored in the first storage means. 1 calculation means, and 2nd calculation means for obtaining the inference result of the regulation stored in the second storage means based on the compatibility.
An image forming apparatus comprising: a third calculation unit that calculates an operation amount based on an inference result of each regulation obtained by each calculation unit.