JPH0310265A - Image forming device - Google Patents

Abstract

PURPOSE:To attain a proper control by providing a method which inferrs a controlled variable used for the control of a process means according to detected quantity of state. CONSTITUTION:A CPU 801 actually performs fuzzy inference and an ROM 803 stores fuzzy regulation and a membership function. An RAM 804 is used for an operation area at the time of performing the fuzzy inference. Then, an I/O 807, an A/D converter 813 which converts an analog signal into a digital signal, a fixing unit 163 which fixes conveyed recording paper by thermal fixing a heater 163-1 which applies heat to a fixing roller, a thermistor 163-2 which detects the temperature of a fixing heater and a control circuit 16-3 which drives the fixing heater from the command of the CPU 801 are provided. Thus, image forming device in which a relation between the quantity of state and the controlled variable is in an unclear relation is smoothly controlled in high accuracy by using the fuzzy inference.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus having a control means using fuzzy inference.

[Prior Art] Conventionally, in a control device for this type of image forming apparatus, formulaic control has been performed based on definite judgments according to state quantities.

For example, in a fixing device, the temperature of the fixing device is generally detected using a temperature sensing element such as a thermistor, and the heating of a heat source such as a heater is controlled after reaching a certain preset temperature level. For example, when the detected temperature is lower than 180 degrees, the heater is turned on (ON), and when the detected temperature is higher than 180 degrees, the heater is turned off (OFF).

In addition, various methods have been devised as improvement measures to reduce fluctuations with respect to the target temperature, such as making the heater O and N times variable depending on the current temperature.

[Problems to be Solved by the Invention] However, image forming devices such as copying machines are subject to large fluctuations depending on the environment, and the relationship between state quantities and control quantities is often governed by an ambiguous relationship, so there are many state quantities. In most cases, it has been difficult to formulate the above-mentioned conventional example.

For example, in the temperature control of the fixing device, when the state variables such as room temperature, number of copies, document density, paper type, and temperature of the fixing device itself change, the fixing ability to fix the toner transferred to the transfer paper may be affected. Although the empirical relationship of complex fluctuations was known, it was difficult to formulate the relationship between these state quantities and control quantities. Specifically, the environment, paper passing,
The degree of heat dissipation differs in the non-sheet feeding state, and in conventional control that turns off above a certain temperature and turns on below a certain temperature, temperature fluctuations (hereinafter referred to as ripples) occur, and the minimum value of this temperature ripple is The temperature needed to be sufficient to fix the toner on the transfer paper, and it was necessary to set the temperature control setting higher than the ideal state. Therefore, there are problems in that extra power is consumed and it is necessary to use more heat-resistant members constituting the fixing device.

The present invention has been made in view of the above-mentioned problems, and its purpose is to produce images for copying machines, laser printers, inkjet printers, etc. in which the relationship between state quantities and control quantities is ambiguous. An object of the present invention is to provide a control device for an image forming apparatus that derives a control amount by performing fuzzy inference on the ambiguous relationship.

[Means for Solving the Problem] In order to achieve the above object, the image forming apparatus of the first invention of the present application includes a plurality of process means for executing the process of forming a visible image on a recording material. The image forming apparatus is characterized by comprising means for detecting at least one state quantity related to the process, and means for inferring a control quantity used for controlling the process means based on the state quantity.

Further, an image forming apparatus according to a second invention of the present application is an image forming apparatus having a plurality of process means for executing a process of forming a visible image on a recording material, the image forming apparatus having at least one process means for forming a visible image on a recording material. State quantity detection means for detecting one state quantity, means for generating a control quantity for controlling at least one of the image forming process means, and rules for qualitatively relating the state quantity and the control quantity are stored. means for storing a function expressing the state quantity and the controlled quantity by at least one ambiguous set; deriving the degree of belonging to the set of controlled quantities from the degree of belonging to the set of state quantity according to the rule; and an inference means for inferring the control amount based on the above.

Further, the image forming apparatus of the third invention of the present application has a process of fixing the visible image formed on the transfer paper by heat, and (17) detecting the visible image formed on the transfer paper. and (17) means for inferring a control amount for controlling the transfer paper on the basis of the state amount.

[Operation] In the configuration of the first invention, the inference means infers a control amount used for controlling the process means based on at least one state quantity related to the process detected by the detection means.

Further, in the configuration of the second invention, the inference means stores information in the function storage means in accordance with a rule stored in the rule storage means for associating the relationship between the state quantity and the control quantity as a qualitative rule. Using a fuzzy set expressing the state quantity and the control quantity, the degree of belonging to the set of control quantities is derived from the degree of belonging to the set of state quantities, and the control quantity is inferred according to the degree.

Further, in the configuration of the third invention of the present application, the inference means may detect the visible image formed on the transfer paper by the means for detecting the visible image formed in the process of fixing the visible image by heat. Based on the state quantity, (17) infer the control quantity for controlling the surface of the transfer paper.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a basic block diagram when the present invention is applied to a fixing device of an image forming apparatus. 801 is a CPU that will be described later.
actually perform fuzzy inference.

A ROM 803, which will be described later, stores fuzzy rules and membership functions. A RAM 804 is used as a work area when performing fuzzy inference, which will be described later. 807 is Ilo, which will be described later; 813 is an A/D converter that converts an analog signal into a digital signal; 163 is a fixing device that fixes the conveyed recording paper by heat fixing; and 163-1 is a heater that applies heat to the fixing roller. , 163-2 is a thermistor that detects the temperature of the fixing heater, and 163-3 is a control circuit that drives the fixing heater according to a command from the CPU 801.

2 FIG. 2 shows the internal configuration of an embodiment of the image forming apparatus of the present invention. In Fig. 2, 100 is a main body that has an image reading function and an image recording function, and 200 is a main body that has a double-sided processing function that turns the recording medium (paper) over during double-sided recording, and performs multiple recordings on the same recording medium. A pedicle having a multiplex recording function, 300 a circulating document feeder (hereinafter referred to as RDF) that automatically feeds documents, and 400 a stapler T-combiner (hereinafter referred to as a stable sorter); Each of the devices 200 to 400 can be used in combination with the main body 100 as desired.

A1 main body (100) In the main body 100, 101 is a document table glass on which a document is placed, and 103 is an illumination lamp (exposure lamp) for verifying the document.
, 105, 107, and 109 respectively, scanning reflection mirrors (scanning mirrors) that change the optical path of reflected light from the original, 111
113 is a lens having focusing and zooming functions, and 113 is a fourth reflecting mirror (scanning mirror) that changes the optical path. 11
5 is an optical system motor that drives the optical system; 117.119.
121 are each a sensor.

131 is a photosensitive drum, 133 is a main motor that drives the photosensitive drum 131, 135 is a high voltage unit, 137 is a blank exposure unit, 139 is a developing device, 141 is a transfer charger, 147 is a separation charger, and 145 is a cleaning device. be.

151 is the upper cassette, 153 is the lower cassette, 171
1 is a manual paper feed slot, 155 and 157 are paper feed rollers, 1
59 is a registration roller. Further, 161 is a conveyor belt 163 that conveys the recording paper on which an image has been recorded to the fixing side.
is a fuser that fixes the transported recording paper by heat fixing,
167 is a sensor used for double-sided recording.

The surface of the photosensitive drum 131 described above is made of a seamless photoconductor using a photoconductor and an electric conductor. The motor 133 starts rotating in the direction of the arrow in the figure. Next, when the predetermined rotation control and potential control processing (preprocessing) of the drum 13 is completed, the original placed on the original platen glass 101 is illuminated by illumination lamp 103 integrated with the first scanning mirror 105. The reflected light from the original is transmitted to the first scanning mirror 105, the second scanning mirror 107, the third scanning mirror 109, and the lens 11.
1 and a fourth scanning mirror 113 to form an image on the drum 131.

The drum 131 is corona charged by a high pressure unit 135. Thereafter, the image (original image) irradiated by the illumination lamp 103i is subjected to photolithographic exposure, and an electrostatic latent image is formed on the drum 131 by a known Carlson process.

Next, the electrostatic latent image on the photosensitive drum 131 is transferred to a developing device 139.
(7) The toner image is developed by the developing roller 140 and visualized as a toner image, and the toner image is transferred onto transfer paper by the transfer charger 141 as described later.

That is, the upper cassette 151 or the lower cassette l-
Transfer paper in 153 1. Alternatively, the transfer paper set in the manual paper feed port 5 171 is fed into the main unit by the paper feed roller 155 or 157, and the leading edge of the latent image and the leading edge of the transfer paper are aligned. Thereafter, the transfer paper passes between the transfer charger 141 and the drum 131 and is discharged to the outside of the main body 100.

After the transfer, the drum 131 continues to rotate, and its surface is cleaned by a cleaning device 145 composed of a cleaning roller and an elastic blade.

B. Pedisicle (200) The pedicle 200 is a deck 201 that can be separated from the main body 100'' and can store 2000 sheets of transfer paper.
and an intermediate tray 203 for double-sided copying.

Further, the lifter 205 of the deck 201, which can accommodate 2000 sheets, is raised according to the amount of transfer paper so that the transfer paper always comes into contact with the paper feed roller 207.

Further, 1 and 211 are paper ejection flaps that switch between the duplex recording side or multiplex recording side path and the ejection side path; 213 and 215 are the conveyance path of the conveyor belt;
is the intermediate tray weight for holding down the transfer paper. The transfer paper that has passed through the paper discharge flapper 211 and the transport paths 213 and 215 is turned over and stored in the intermediate tray 203 for double-sided copying. Reference numeral 219 denotes a multiple flapper for switching between double-sided recording and multiplex recording, and is disposed between conveyance paths 213 and 215, and guides the transfer paper to the multiplex recording conveyance path 211 by rotating upward. Reference numeral 223 is a multiple sheet discharge sensor that detects the end of the transfer sheet passing through the multiple flapper 219. 225
is a paper feed roller that feeds the transfer paper to the drum 131 side through the path 227.

229 is a discharge roller that discharges the transfer paper to the outside of the machine.

When performing double-sided recording (double-sided copying) or multiplex recording (multiple overlapping copying), first raise the paper ejection flapper 211 of the main body 100 upward, and move the copied transfer paper to the conveyance path 2 of the pedicle 200.
13 and stored in the intermediate tray 203 via 215. At this time, the multiple flapper 219 is lowered during double-sided recording, and raised during multiple recording (.

This intermediate tray 203 can store up to 99 sheets of transfer paper, for example. The transfer paper stored in the intermediate tray 203 is held down by the intermediate tray weight 217.

During the next back-side recording or multiplex recording, the transfer paper stored in the intermediate tray 203 is moved one by one from the bottom to the path 2 by the action of the paper feed roller 225 and the weight 217.
27 to the registration rollers 159 of the main body 100.

C, RDF (circulating document feeder) (300) RDF
In 300, 301 is a stacking tray on which a bundle of originals 302 is set. First, for single-sided originals, half-moon roller 3
04 and a separation roller 303 from the bottom of the document bundle 302, and the separated documents are transferred to the platen glass 10 by a conveyance roller 305 and a full-surface belt 306.
The conveyance is stopped after passing through passes ① to ② to the exposure position No. 1, and then the copying operation is started. After copying is completed, the original on the platen glass 101 passes through paths III and IV, is sent to paths V and 6 by a large transport roller 307, and is returned to the uppermost surface of the original bundle 302 by a discharge roller 308.

Reference numeral 309 denotes a recycle lever for detecting document circulation. When the document feed starts, the recycle lever 309 is placed on top of the document stack, and the documents are fed one after another until the trailing edge of the final document passes through the recycle lever 309. One circulation of the original is detected by the original falling onto the stacking tray 301 due to its own weight.

Next, in the case of a double-sided document, the document is guided from path I and ■ to path ■ as described above, and after the copying is completed, the leading edge of the document is guided to the path by switching the rotatable switching flapper 310, and the leading edge of the document is guided to the path by the conveyance roller 305. The document is conveyed and stopped on the platen glass 101 by the full-surface belt 306 through the path (3). That is, the configuration is such that the rotation of the large conveyance roller 307 causes the document to be reversed along the routes of passes (1) to (4) to (IV) to (2).

It is also possible to count the number of originals by transporting the original bundle 302 one by one through passes ①-II-IIT9-IV-V-6 until one cycle is detected by the recycle lever 309.

D. Stable sorter (collation device with staple)
(400) The stable sorter 400 has a fixed non-sort tray 411 with 20 bins, and performs collation.

In the sort mode, the copied sheets are sequentially ejected from the paper ejection roller 229 of the main body, enter the transport roller 401 of the sorter 400, pass through the transport bus 403, and are ejected from the ejection roller 405 to each bin of the tray 412. Each time, a bin shift motor (not shown) moves each bin up and down to collate the bins. The stapling device 420 staples the sheets in each bin while moving the bins one by one.
staple) L/line (.

FIG. 3 shows an example of the arrangement of the operation panel provided on the main body 100 described above. The operation panel has a key group 600 and a display group 700 as described below.

E. Key group (600) In Fig. 3, 601 is an asterisk (*) key, which is used by the operator (user) when in the setting mode, such as setting the remaining amount of binding or setting the size of original frame eraser. .

Reference numeral 606 is an all reset soft key, which is pressed to return to the standard mode. This key 602 is also pressed when returning from the auto-shutoff state to the standard mode.

605 is a copy start key (copy start key);
Press to start copying.

A clear/stop key 604 functions as a clear key during standby and as a stop key during copy recording. This clear key is also used to cancel the set number of copies.

Also, press the stop key to interrupt continuous copying.

The copying operation stops after the copying at the time when the button is pressed is completed.

Numeric keys 603 are pressed to set the number of copies. It is also used to set the * (asterisk) mode. Reference numeral 619 is a memory key in which the user can register frequently used modes.
You can register four modes of M2.

Copy density keys 611 and 612 are pressed when manually adjusting the copy density. 613 is an AE key, which is used to automatically adjust the copy density according to the density of the original.
Or press to cancel AE (automatic density adjustment) and switch density adjustment to manual. A cassette selection key 607 is pressed to select the upper cassette 151, the middle cassette 153, and the lower cassette 201. Further, when a document is placed on the RDF 300, APS (automatic paper cassette selection) can be selected using this key 607. When APS is selected, a cassette of the same size as the original is automatically selected.

Reference numeral 610 is a same size key, which is pressed to make a same size (original size) copy. Reference numeral 616 is an auto-magnification key, which is pressed to automatically reduce or enlarge the original image according to the specified transfer paper size.

A double-sided key 626 is pressed to make a double-sided copy from a single-sided original, a double-sided copy from a double-sided original, or a single-sided copy from a double-sided original. Reference numeral 625 is a binding key that can create a binding margin of a specified length on the left side of the transfer paper. 6
24 is a photo key, which is pressed when copying a photo original. 623 is a multiple key, which is pressed when creating (combining) an image from two originals on the same side of transfer paper.

Reference numeral 620 denotes a document frame erase key, which the user presses when erasing the frame of a standard size document. At this time, the size of the document is set using the asterisk key 601. Reference numeral 621 is a sheet frame erase key, which is pressed to erase the frame of the document according to the cassette size.

Reference numeral 614 is a paper ejection method selection key that selects the paper ejection method of stable, sort, and group. The selection mode can be canceled, and if a sorting tray (sorter) is connected, the sort mode and group mode can be selected or the selection mode can be canceled.

Reference numeral 615 is a paper folding selection key, which is used to select either Z-fold, which folds recorded paper of A3 or B4 size into a Z-shaped cross section, or half-fold, which folds recorded paper of A3 or B4 size in half. You can cancel that selection.

F Display group (700) In Fig. 3, 701 is an LCD (liquid crystal) type message display that displays information regarding copying. The copy magnification set by the magnification key 608, 609, the same magnification key 610, and the zoom key 617, 618 can be displayed. This display 701 is a semi-transparent spiral liquid crystal and uses two colors for the backlight.Normally, the green backlight is lit, and the orange backlight is lit when there is an abnormality or when copying is not possible.

Reference numeral 706 denotes an equal magnification display, which lights up when equal magnification is selected. A color developer display 703 displays the number of copies or a self-diagnosis code.

705 is a used cassette indicator, which indicates the upper cassette 15.
1. Displays whether either the middle cassette 153 or the lower cassette 201 is selected.

704 is an AE display, and the AE key 613
Lights up when (automatic density adjustment) is selected. A preheating indicator 709 lights up when a double-sided copy is made from a double-sided original or a double-sided copy is made from a single-sided original.

When using the RDF300 in standard mode, the settings are 1 copy, density AE mode, automatic paper selection, same size, and 1-sided copying from a 1-sided original. When the RDF300 is not in use, the standard mode is set to 1 copy, manual density mode, same size, and 1-sided copying from a 1-sided original.

The difference between when the RDF 300 is used and when it is not used is determined by whether or not a document is set on the RDF 300.

A power lamp 710 lights up when a power switch (not shown) is turned on.

G. Control Device (800) FIG. 4 shows an example of the configuration of the control device 800 of the embodiment shown in FIG. In FIG. 4, 801 is a central processing unit (CPU) that performs arithmetic control for executing the present invention, and uses, for example, a 16-bit microcomputer. 803
is a read-only memory (ROM) in which a control procedure (control program) according to the present invention is stored in advance;
PU801 controls each component device stored in this ROM803. Reference numeral 805 denotes a random access memory (RAM) which is a main storage device used for storing input data and as a working storage area.

807 is an ink face (
Ilo), 809 is an ink face for inputting human input signals such as the image tip sensor 121 and transmitting input signals to the CPU 80], and 811 is an ink face for controlling input/output of the key group 600 and the display group 700. These ink faces 807, 809, and 811 use, for example, NEC's input/output circuit board μPD8255.

Note that the display group 700 is each display device shown in FIG. 3, and uses, for example, an LED (light emitting diode) or an LCD (liquid crystal display). Further, the key group 600 is each key shown in FIG. 3, and is configured so that the CPU 801 can know which key has been pressed using a known key matrix.

H0 Operation Example Next, an example of temperature control operation when the present invention is applied to a fixing device of an image forming apparatus will be described. Three state quantities are used when performing temperature control: (1) temperature deviation of the current temperature with respect to the target temperature, (7) (2) temperature gradient, which is the amount of temperature change per unit time, and (2) paper area.

However, other factors such as room temperature, set number of sheets, document density paper size, and standing time may also be used.

On the other hand, as a control amount when performing temperature control, ■ heater 163
-1 ON time is used.

However, the target temperature of the fixing device, the copy interval, the speed of the fixing heat exhaust fan, etc. may be controlled.

FIG. 5 shows fuzzy sets called membership functions of the state quantities and control quantities described above.

Temperature deviation, temperature gradient, paper area, and heater ON time are broadly divided into several groups. For example, in the case of temperature deviation, 1) NB (Negative Big) is a negative value and has a large absolute value.

2) NS (Negative Small 1) Negative value with small absolute value.

3) 20 (Zero) 8 Around 0.

, 4) PS (Positive Small) A positive value with a small absolute value.

5) PB (Positive Small I) A positive value with a large absolute value.

shall be. However, this method of division is just an example, and it is also possible to divide it into seven stages. Here, the degree of belonging to each set is expressed as a value from O to 1. Fifth
In the figure, (a) is a membership function of temperature deviation, (b) is a membership function of temperature gradient, (c) is a membership function of paper area passing through the fixing device per unit time, and (d) is a membership function of heater ON. It is a membership function of time.

Taking 20 (zero) in (a) as an example, when the temperature deviation is OoC, the degree of belonging to the set ZO is 1.0, and if the temperature deviation is 1.5°C or -1.5
°C means that the degree of belonging to the set ZO is 0.5. The same applies to other cases.

Next, from the state quantities of temperature deviation, temperature gradient, and paper area, the heater O
A method for calculating N time will be described.

For example, the following fuzzy rule is used to determine the heater ON time. For the sake of simplicity, I will explain it using two rules.

(Rule 1) If temperature deviation = PB and temperature gradient = ZOand
Paper area = ME then Heater ON time = PB (Rule 2) If Temperature deviation = PS and Temperature gradient = ZOand
Paper area/ME then Heater ON time=ps In this way, fuzzy rules are set as necessary. This rule can be appropriately determined by empirical rules, experiments, etc. Alternatively, it may be set randomly by a computer or according to an appropriate algorithm.

Here, the part below If is the antecedent part (conditional part), and then
The following is the consequent part (conclusion part).

FIG. 7, which shows the fuzzy rules in the case of this embodiment in FIG. 6, is an example of calculating the heater ON time by fuzzy reasoning using the above-mentioned (Rule 1) and (Rule 2).

As an example, consider a case where temperature deviation=X and temperature gradient=y.

In (Rule 1), from the membership function of temperature deviation,
It is included in the set of PB to the degree μX with respect to the input is included in the set of MEs to a degree of μ2. After that, take the minimum value of μX, μy, and μZ, and let that value be the degree to which the condition part of Rule 1 is satisfied. When the MIN (minimum value) calculation is performed between the value 1 and the membership function of the heater ON time, a trapezoid shown by the hatched part of S is obtained.
Similar calculations are performed for (Rule 2), and a trapezoid shown by the shaded part of T is obtained. The area of this trapezoid is considered to represent the probability that the rule itself indicates the control amount to be derived.

After that, the maximum value of the set of S and the set of T is taken, and a new set shown by the diagonal line part of U is created. The value obtained by calculating the center of gravity of this set is set as the ON time of the heater obtained by fuzzy inference. That is, the intersection of the perpendicular line passing through the center of gravity and the horizontal axis is the control amount to be determined. Same thing in the 6th
This is done for all of the fuzzy rules shown in the figure.

Note that instead of the above-mentioned center of gravity, the average of the control amounts obtained from each rule may be simply taken. Alternatively, the area of the combined figure U may be divided into two.

Next, the operational flow of the present invention will be explained with reference to FIG. This is a flowchart of a 10ms interrupt.

2 First, depending on the heater ON time t set in FIG.
It is determined whether or not is 0 (8-1), and if it is 0, a fuzzy inference subroutine is called to set the heater ON time t by fuzzy inference, and then the process returns.

On the other hand, if the judgment in (8-1) is negative, the heater ON time t
8-3), and if it is positive, subtract 1 from the value of 7 (8-4), then judge whether the heater ON time t is O or not (8-5). ) If the value is 0, the fuzzy inference subroutine (8-7) is called, and then the process returns. If the determination in (8-5) is negative, the heater is turned on (8-6) and the process returns.

If the heater ON time t is negative in the judgment in (8-3), the value of t is added by 1 (8-8), and then it is determined whether the heater ON time t is 0 or not (89). ), O, calls the fuzzy inference subroutine (877), and then returns. If the judgment in (89) is negative, the heater is set to 0'FF (8-10,) and the process returns.

Next, the fuzzy inference subroutine operation flow will be explained with reference to the flowchart of FIG.

First, measure the temperature of the fixing roller with the thermistor 1632 (9-1), and calculate the deviation of the current temperature from the target temperature and the temperature gradient, which is the temperature change per unit time (8-1).
2).

In addition, the paper area is calculated from the paper size specified by the user or the RDF 300 (8-3) As mentioned above, in this implementation, based on the fuzzy rule, when the temperature deviation is large and the temperature gradient is small, When the paper area is large, the energization time to the heating means is lengthened; when the temperature deviation, temperature gradient, and paper area are medium, the energization time is medium; when the temperature deviation is small, and the temperature gradient is large, When the paper area is small, the time during which electricity is applied to the heating means is shortened.

After that, for all the fuzzy rules in FIG. 6, calculate the degree of belonging to the fuzzy set of the control quantity from the degree of belonging to the fuzzy set of the state quantity according to each fuzzy rule using the method described above.8-4) (8-5) The maximum value of the set belonging to the rule is calculated 86), the most likely control amount is calculated by finding the center of gravity 8-7), and the center of gravity is set as the heater ON time t (8-8).

The heater ON time t is the heater ON time t during the 10ms interrupt.
It is used when controlling the N time, and the value is set in units of 10m5.

As explained above, according to the above embodiments of the present invention, images of copiers, laser printers, inkjet printers, etc. in which the relationship between state quantities and control quantities is dominated by ambiguous relationships (i.e., In a forming apparatus, a control amount can be derived from state variables that are intricately related, and image formation can be performed according to the environment at that time.

As a result, it is possible to minimize power consumption, paper jams, damage, etc. of the image forming device, and it is also possible to perform process control optimally, improving image quality and making image formation more reliable. 5 It is possible to significantly improve performance.

In particular, if the present invention is applied to a fixing device, the power consumption of the fixing device can be minimized, and there is no need to use heat-resistant members constituting the fixing device. Furthermore, since fixing performance can be improved against environmental changes, image quality is stabilized and reliability is improved.

Note that the fuzzy rules and membership functions used in this example are merely examples, and the type and number of rules and functions can be changed depending on the process and accuracy of the applied image forming apparatus. . At this time, the ambiguous set (set of membership functions) stored in the function storage means can be changed by an instruction from the operation panel shown in FIG. 3, for example. Here, the fuzzy set can be changed by, for example, storing membership functions suitable for various cases in advance in an IC card as an external storage device,
This can be realized by reading data from this IC card into the function storage means. Also, at this time, a large number of IC cards are made in consideration of various factors (with ambiguity) that affect the control amount, such as temperature, humidity, and differences in paper and toner types in each country.
It can also be used differently depending on conditions such as the season.

Further, the inference means may calculate the optimum control amount during actual control as described above, or may store the results of calculations in advance based on the state quantities and the fuzzy set in a ROM table. You can also search for .

In the above embodiment, the image forming process of electrophotography was explained as an example, but the image forming process is not limited to this. For example, in an inkjet recording device, ink is ejected onto a recording material and then dried. Fuzzy inference can be used for processes as well. In other words, it is possible to control the time for sending hot air or hot air for drying.

In the above embodiment, the fixing process was mainly explained as an example of the process, but the charging time of the charging means,
The fuzzy reasoning of the present invention can be applied to various processes such as the exposure time of the exposure means, the developing speed of the developing means, the transfer speed of the transfer means, the paper feeding speed of the paper feeding means, and the conveying speed of the conveying means.

Note that the present invention is naturally applicable not only to black and white image forming apparatuses but also to color image forming apparatuses.

[Effects of the Invention] According to the present invention, the control of an image forming apparatus in which the relationship between the state quantity and the control quantity is governed by an exact relationship can be performed smoothly and with high accuracy by using fuzzy inference. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a basic program diagram of the present invention, Fig. 2 is an overall configuration diagram of a copying machine according to an embodiment of the present invention, and Fig. 3 is an operation panel of a copying machine according to an embodiment of the present invention. Fig. 4 is a schematic diagram of a control device according to an embodiment of the present invention. , a diagram illustrating fuzzy rules, an explanatory diagram of the fuzzy inference method, an interrupt flowchart, and a diagram when the present invention is applied to a fixing device. 801 ・ ・ 803 ・ ・ 805 ・ ・ 807 ・ ・ 813 ・ ・ 63-1 1 63-2 63-3 PU OM AM 10 A/D converter... Heater... Thermistor... Drive circuit 9 0 180-90 0 90 180 Fig. 5 Membership function Heater ON time (msec) (E is PB and ()/PSand (ll ZOand (" ZOand (〃 ZOand (" ZOand nd (〃 ZOand (” ZOand DE is ZOand 〃 ZOand ” ZOand 〃 PBand ” PSand ll ZOand // N5and // NBand ” ZOand 〃 ZOand ” ZOan d S P i s ME) → H 〃 ME) → H 〃 ME) → H 〃 ME) → H 〃 ME) → H 〃 ME) → H 〃, ME) → H 〃 ME) → H / ME) → H 〃 LA) → H 〃 SM) → H sPB 5PS isZ. sNB 5NS isZ○ sPS 5PB isZ. sPS sNS Figure 6 Fuzzy rules 673 Figure 9 Flowchart when the present invention is applied to a fixing device

Claims (1)

[Scope of Claims] (1) In an image forming apparatus having a plurality of process means for executing a process of forming a visible image on a recording material, means for detecting at least one state quantity related to the process; An image forming apparatus comprising: means for inferring a control amount used for controlling the process means based on the state amount. (2) In an image forming apparatus having a plurality of process means for executing a process of forming a visible image on a recording material, means for detecting at least one state quantity related to the process, the state quantity and the process means for storing a rule that qualitatively relates a control amount for controlling at least one of the means; means for storing a function expressing the state amount and the control amount as at least one ambiguous set; An image forming apparatus comprising: a means for deriving a degree of belonging to the set of control variables from a degree of belonging to the set of state quantities, inferring the control variable according to the degree, and forming the image. (3) The inference means is a goodness-of-fit derivation means for deriving the degree to which at least one state quantity at a certain point in time belongs to a function expressing the state quantity of the antecedent part of the rule as an ambiguous set; The degree to which the function expressing the control amount of the consequent part as an ambiguous set matches the state amount at that point is expressed as:
means for inferring using the degrees derived by the fitness deriving means; means for synthesizing the results inferred by the inference means for a plurality of predetermined rules; and actual control from the functions derived by the synthesizing means. means for deriving a quantity, which derives the degree of belonging to the set of controlled quantities from the degree of belonging to the set of state quantities according to the rule;
3. The image forming apparatus according to claim 2, wherein the most likely control amount is inferred. (4) Claim 2 further comprising means for changing the ambiguous set stored in the function storage means.
The image forming apparatus described in . (5) The image forming apparatus according to claim 3, wherein the changing means has an operation section, and the operation section can issue an instruction to change the fuzzy set. (6) The changing means has an external storage means, and changes the ambiguous set stored in the function storage means based on the ambiguous set stored in the external storage means. The image forming apparatus described above. (7) The image forming apparatus according to claim 6, wherein the external storage device is an IC card. (8) The image forming apparatus according to claim 2, further comprising means for storing a function in which the state quantity and the control quantity are expressed as at least one ambiguous set, at the end points of a triangle. (9) The image forming apparatus according to claim 2, further comprising means for storing, as an arbitrary function, a function in which the state quantity and the control quantity are expressed as at least one ambiguous set. (10) The image forming apparatus according to claim 3, wherein the suitability deriving means and the inference means include a minimum value calculation means. (11) The image forming apparatus according to claim 3, wherein the suitability deriving means and the inference means include a multiplication means. (12) The image forming apparatus according to claim 3, wherein the inference means includes maximum value calculation means. (13) The image forming apparatus according to claim 3, wherein the control amount deriving means includes means for deriving a center of gravity. (14) At least one of the rule storage means, the function storage means, and the inference means is a mapped ROM.
3. The image forming apparatus according to claim 2, wherein: is used. (15) The image forming apparatus according to claim 2, wherein the process is a process of forming a latent image on a photoreceptor, making it visible by a developing means, and transferring the visible image onto transfer paper. (16) The process means includes at least one of a charging means, an exposure means, a developing means, a transfer means, a paper feeding means, a conveying means, a fixing means, and an image forming mode setting means. The image forming apparatus according to item 2. (17) means for detecting a predetermined state quantity related to the fixing process in an image forming apparatus having a process of fixing a visible image formed on a transfer paper by heat; controlling the fixing process based on the state quantity; An image forming apparatus comprising: means for inferring a control amount for. (18) The predetermined state quantity is at least one of room temperature, set number of sheets, document density, paper size, standing time, temperature deviation from the target temperature of the fixing device, and temperature gradient which is the temperature deviation per unit time. Yes, the control of the fixing process includes:
18. The image forming apparatus according to claim 17, wherein control is performed on at least one of the following: a time period for energizing the heating means of the fixing device, a target temperature of the fixing device, a copy interval, and a speed of a fixing heat exhaust fan. (19) Furthermore, means for storing a rule that relates the state quantity and the control quantity as a qualitative rule, means for storing a function expressing the state quantity and the control quantity as at least one ambiguous set, and the rule 18. The image according to claim 17, further comprising: inference means for deriving the degree of belonging to a set of controlled quantities from the degree of belonging to a set of state quantities according to the above, and inferring the most likely controlled quantity. Forming device. (20) The inference means includes a goodness-of-fit derivation means for deriving the degree to which at least one state quantity at a certain point in time belongs to a function expressing the state quantity, which is an antecedent part of the rule, as an ambiguous set; means for inferring the degree to which a function expressing the control amount, which is a consequent part, as an ambiguous set matches the state amount at that time, using the degree derived by the fitness deriving means; means for synthesizing the results inferred by the inference means for a plurality of rules; and means for deriving an actual control amount from the function derived by the synthesis means; Deriving the degree of belonging to the set of control variables from the degree of belonging,
20. The image forming apparatus according to claim 19, wherein the most likely control amount is inferred.