JP3265306B2 - Image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for controlling a recording density of an electrophotographic apparatus or the like, and more particularly to an image forming method capable of always forming an appropriate image.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system, an electrostatic latent image formed on a carrier by a predetermined method is supplied with colored fine particles called toner from a developing device and developed. Normally, the toner is charged with a polarity opposite to that of the electrostatic latent image, and is developed by being electrostatically attracted to the electrostatic latent image.

[0003] As a method of charging a toner to a polarity opposite to that of an electrostatic latent image, a developer is composed of a toner and a carrier (generally, such a developer is called a two-component developer), and both are mixed and stirred. There is known a method of frictionally charging each other.

However, in a developing method using a two-component developer, the toner can be sufficiently charged, but only toner is consumed in development, so that the toner density (image density) in the developer is always constant. Control is required to keep it constant. Therefore, as an image forming method for controlling the recording density, a method of measuring the toner density of the developer and controlling the toner replenishing amount based on the toner density is used.

In such an image forming method, as a method for measuring the toner density of the developer, for example, a reference electrostatic latent image pattern (a detection pattern for detecting an image density related value) on a photoreceptor is used. After developing this, an indirect developer toner concentration measuring method that photoelectrically measures the density of the developed image using an optical sensor, or measuring the weight of the developer or measuring the magnetic permeability A direct developer toner concentration measurement method using a toner concentration sensor is used.

Here, a conventional image forming method will be specifically described by taking a case where a P sensor (photo sensor) is used as an optical sensor as an example.

FIG. 52 shows a copying apparatus to which a conventional image forming method is applied. An image of a document (not shown) on a contact glass plate 701 is formed by a first mirror 702, a second mirror 703, and an in-mirror lens 704. , And is projected on the surface of the photosensitive drum 706 via the third mirror 705. Rotation of the photosensitive drum 706 (counterclockwise in the figure)
In synchronization with the first mirror 702 and the second mirror 703
Is driven to scan leftward at a predetermined speed ratio. The electrostatic latent image on the photosensitive drum 706 is transferred to the developing roller 70 of the developing device 707.
7a (a two-component developer composed of a toner and a carrier). Thus, the photosensitive drum 706
The toner image formed on the surface of the transfer charger 70
At 8 the image is transferred to the recording paper. The recording paper is sent to a fixing unit (not shown) by a separation belt 709.

On the other hand, in the image projection field in the home position of the first mirror 702, as illustrated, and white pattern P ₀ and black pattern P ₁ as the detection pattern is attached, a first mirror 702 is exposed and scanned , An electrostatic latent image of a white pattern P ₀ and a black pattern P ₁ is continuously formed on the photosensitive drum 706.

A developing device 707 and a transfer charger 708
A P sensor (photo sensor) 710 for detecting the toner density on the surface of the photoconductor drum 706 is disposed between them, and a detection signal of the P sensor 710 is amplified and waveform-shaped by an amplifier 711 and A / D-converted. A /
The data is D-converted (analog-digital converted) and output to an MPU (microprocessor) 713.

The MPU 713 calculates the density ratio (V _SP / V _SG ) of the corresponding toner image of the white pattern P ₀ and the black pattern P ₁ , determines the toner supply amount based on the density ratio, and corresponds to the toner supply amount. During this time, a solenoid energizing instruction is given to the solenoid driver 714. When the driver 714 inputs a solenoid energizing instruction, the clutch solenoid 715
Turn on electricity. When the clutch solenoid 715 is energized, the toner cut-out roller 716 rotates, and toner is supplied to the developing device 707 from the toner storage tank.

Reference numeral 717 denotes a charger for uniformly charging the photosensitive drum 706. Reference numeral 718 denotes a predetermined portion of the surface of the photosensitive drum 706 charged by the charger 717 (a white pattern P ₀ and a black pattern P ₁ are projected). 2) shows an erase lamp for removing static electricity from a portion to be erased.

[0012] Here, by controlling the energizing of the erase lamp 717, the white pattern P ₀ and one photoreceptor drum 70 for each electrostatic latent image of the black pattern P ₁ is copied ten
6 and the toner density at that time is
Detected by 0.

The control operation of the recording density in the above configuration will be described in detail with reference to FIGS. The toner concentration detection using the P sensor 710
The change in the density of the pattern image developed above is captured as a change in the toner density in the developer, and the toner density in the developer is controlled.

As shown in FIG. 53, the toner concentration is detected at the first sheet when the start key is pressed after the power is turned on and at every tenth sheet thereafter, and when the toner concentration is detected to be low. Indicates that the clutch solenoid 715 is turned on for each sheet for 10 sheets until the next toner concentration detection timing.
Then, the supply of toner through the toner cut-out roller 716 is continued. On the other hand, the erase lamp 717 turns off in synchronization with the toner density detection timing, and an electrostatic latent image of the white pattern P ₀ and the black pattern P ₁ is formed on the photosensitive drum 706.

When the pattern image (image after development) of the white pattern P ₀ and the black pattern P ₁ comes to the position of the P sensor 710,
The P sensor 710 turns on the light emitting diode, irradiates the pattern image with light, receives the reflected light with the phototransistor, and detects the density of the pattern image.

[0016] As shown in FIG. 54, the output of the P sensor 710, (for white pattern P ₀₎ when the toner density is low
A large value because the reflected light becomes stronger in, becomes a small value since the reflected light becomes weak when the toner density is high (when the black pattern P _1). MPU 713 is a P sensor 7
Input data from 10 consecutive 4 times the average taken V _SG to 9-16 before the time point of falling below 2.5V, fell from 2.5V continuously input data is four times from P sensor 710 Thereafter, the average of the subsequent 9 to 16 is taken as V _SP .

When the toner concentration in the developer is appropriate, FIG.
As shown in (a), when V _SG is 4 V, V _SP is about 0.44
Assuming that V is V, when the toner concentration in the developer decreases, the pattern image developed on the photosensitive drum 706 also becomes thin, so that V _SP is 0.44 as shown in FIG.
V. On the other hand, when the toner density is high, as shown in FIG. 55 (c), the pattern density becomes high, so that V _SP becomes lower than 0.44V. Therefore, it is possible to determine whether or not to supply toner from the value of V _SP . Actually, since V _SG is not necessarily 4 V, the magnitude of V _SP / V _SG is determined based on V _SP / V _SG = 1/9 (≒ 0.44 / 4) using the ratio of V _SP and V _SG. Is used to control toner supply.

[0018]

However, according to the conventional image forming method, toner replenishment is started after the toner density becomes low. Therefore, when a document that consumes a large amount of toner continues, the toner density becomes low. Is abrupt, and it is difficult to obtain a stable toner concentration.

Further, in the conventional image forming method, since the time delay between the replenishment of the toner and the increase in the toner density is not taken into consideration, the range of the variation in the toner density becomes large. In other words, There was also a problem that the control accuracy was not sufficient.

Further, since the detection pattern is created unconditionally once every 10 copies, for example, when a plurality of copies are made from a document which consumes a small amount of toner,
There is also a problem in that unnecessary detection patterns are created and toner is consumed more than the amount of toner consumed for copying.

In addition, since the toner density is always detected once every ten copies, if a document consuming a large amount of toner continues, it is not possible to cope with a change in the toner amount. There were also points.

Further, according to the conventional image forming method, the amount of toner consumed between the detection patterns varies greatly depending on the pixel density of the document, the aging environment, and the like. There is also a problem that it is not possible to supply toner appropriately in accordance with the toner consumption. Here, a change in the pixel density of the document between the detection patterns (in other words, a change in the toner consumption) is a disturbance factor in the feedback system of the optical sensor output. In order to improve the image quality, it is conceivable to increase the feedback amount by increasing the frequency of generation of the detection pattern. However, if the detection pattern is generated frequently, wasteful toner consumption increases, and the load on cleaning increases. Will occur.

On the other hand, as shown in JP-A-63-33704, first detecting means for counting the image forming signal and detecting the amount of consumed toner and the operating time of the developing roller are obtained. There is disclosed an image forming apparatus that replenishes toner to maintain a constant toner concentration based on a second detecting unit that detects the amount of consumed toner. Is not constant under the influence of the fluctuation of the charging ability (CA) of the carrier due to the deterioration of the developer due to the deterioration of the developer.
There is a problem that it is difficult to maintain an ideal image quality (toner density) according to the state (time environment).

Further, a two-component developer generally used in an electrophotographic system has a decrease in CA (charging ability of a carrier) due to deterioration of the developer with time, and also in environmental conditions around the developer at low temperature and low humidity. The charge accumulation increases and Q / M increases. At high temperature and high humidity, the charge leakage increases and Q / M increases.
There is a development in which M decreases. Although there are many factors that mutually affect the Q / M in this way, in other words, the optimum control value is determined in consideration of a large number of pluralistic information that influences the control target. Despite the necessity, the control value is determined in consideration of only the influence of the factors 1 and 2 alone, so that it is not possible to cope with a change in state (environment over time) and maintain high image quality. There was also a problem that it could not be done.

Further, in the conventional image forming method, when the user manually adjusts the image density, ambiguous information such as dark and light is input and processed as a quantified step-like numerical value. There is also a problem that the image density cannot be adjusted to a user's desired image density.

Further, when the amount of toner remaining in the toner hopper changes, the transport efficiency of the toner replenishing member changes, so that even if the toner is replenished under the same conditions, the amount of toner replenishment cannot be kept constant. there were.

Further, when a large amount of toner is continuously consumed and a large amount of toner needs to be replenished, as in the case of continuous black solid image formation, the amount of toner greatly fluctuates.
There is also a problem that it is difficult to maintain a target image density.

In the conventional image forming method, when the deterioration of the developer is detected, the control of the image density is performed without specifying the cause of the deterioration of the developer. There was also a problem that it was not possible.

In the conventional image forming apparatus, since the temperature and humidity sensor for measuring the temperature and humidity environment where the developer is placed is disposed inside the developing device, the temperature and humidity sensor becomes dirty with toner and has a detection capability. However, there is a problem that the temperature is reduced.

The present invention has been made in view of the above, and an object of the present invention is to be able to make comprehensive judgments by seeking multidimensional information and to cope with all conceivable temporal environments.

[0031]

According to a first aspect of the present invention, there is provided an image forming method using an electrophotographic method. The relative humidity, the toner density, and the respective membership functions for the difference from the previous measurement value of the toner density, and the difference between the relative humidity, the toner density, and the previous measurement value of the toner density in the developing device used for the membership function A step of inferring the amount of change in the developing ability based on the respective control rules, a step of converting the inference result of the amount of change in the developing ability into a developing ability, and a grid control amount corresponding to the determined developing ability. Functions for the exposure control amount, the developing bias control amount, and the toner replenishment control amount. The grid control amount, the exposure control amount, the developing bias control amount, and the toner replenishment control amount are determined based on the respective control rules for the grid control amount, the exposure control amount, the developing bias control amount, and the toner replenishment control amount. Inferring and determining.

Further, the image forming method according to claim 2 is
2. The image forming method according to claim 1, wherein a scale of the membership function is changed based on a detection result of a detection pattern by an optical sensor.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the image forming method according to the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a configuration of an embodiment of an image forming apparatus to which an image forming method of the present invention is applied, and a photosensitive drum (not shown).
P sensor (photo sensor) 1 for reading a detection pattern for detecting an image density related value formed thereon
01 and the image-related value detected by the P sensor 101 are A / D
A / D converter 102 for converting (analog-to-digital conversion) and inputting digitally-converted image-related values to V
MPU 103 for calculating _SP / V _SG (= R) and MPU 10
3 and the contents of the latch 104 (the previous value of R) and the R output from the MPU 103.
A subtractor 105 for calculating a difference dR from (the value of R this time);
A fuzzy controller 106 for inputting R and dR from the MPU 103 and the subtractor 105 to control the amount of toner replenishment and outputting an error process, and a toner supply signal from the fuzzy controller 106 for a corresponding time and a clutch solenoid It comprises a solenoid driver 107 for energizing 108 and an error counter 109 for inputting an error processing output from the fuzzy controller 106 and counting the number of errors.

With the above configuration, an image forming method according to this embodiment will be described. Here, as in the past, 10
It is assumed that a detection pattern is created on the photosensitive drum once and developed.

[0036] First, the developed detection pattern was read by P sensor 101, which was A / D converted by the A / D converter 102, it calculates the V _SP / V _SG in MPU 103.
This output is input to the fuzzy controller 106, and at the same time, the difference dR between the value of V _SP / V _SG = R and the value of R (contents of the latch 104) is obtained and input to the fuzzy controller 106. The fuzzy controller 106
The toner supply amount and error processing output are performed according to the rules in Table 1.

[0037]

[Table 1]

In the fuzzy controller 106,
The membership function shown in FIG. 2A is set for the R input, the membership function shown in FIG. 2B is set for the dR input, and the toner supply output shown in FIG. A membership function is set as shown in FIG.

Here, for example, R = 0.475, dR = 0.
025, the fuzzy controller 106
Are the rules in Table 1 and FIGS. 2 (a), 2 (b) and 2 (c).
According to each membership function of, as shown in FIG.
Set the toner supply amount. First, R = 0.475 and FIG.
The value of the intersection of the membership function of each rule in (a) is calculated (0 if there is no intersection). Next, the value of the intersection of dR = 0.025 and the membership function of each rule in FIG. 2B is calculated. Subsequently, the minimum value of the calculated value at the intersection of each rule is calculated.

By the calculations so far, as shown in the figure, rules 1 to 0, rules 2 to 0.5, rules 3 to 0.5,
Values of 0 are obtained from rules 4 to 14. Next, the value of the membership function of the toner supply output corresponding to this value (the value of the membership function in FIG. 2C) is obtained. In this example, the area of 0.5 or less of the toner supply output (medium) and (large) is obtained from the rules 2 and 3 indicated by oblique lines in FIG. 3 (others are 0). The synthesis of the outputs of these rules 1 to 14 is calculated to obtain the trapezoid shown at the right end in the figure. Finally, a defuzzification process is performed to determine the toner supply amount. The defuzzification process is generally performed by calculating the center of gravity of the composite output, and here, 5 (g) is output. Using this value, the solenoid driver 107 is used for each copy as in the related art.
To turn on clutch solenoid 108
Then, the determined toner amount is supplied.

Further, in the case of rules 13 and 14, (R
Is minimum or maximum), the error counter 10
When the count of 9 is incremented by one and the count is continuously performed three times, the toner supply is stopped and an error display is performed as error processing.

As described above, in the image forming method of this embodiment, the use of dR improves the accuracy of density control compared to the case of using only R. In particular, the control accuracy when the density changes rapidly is remarkably improved.

Further, by performing fuzzy inference using the membership function, it is defined by a control function such that the image area ratio of the document is not constant or there is a time delay until the supplied toner is reflected on the toner density. Factors that are difficult to do,
Processing can be performed approximately, and recording density control becomes robust.

In this embodiment, the MPU 103TO fuzzy controller 106, the latch 104, and the subtractor 105 are separately provided. However, it is needless to say that the MPU 103 may be configured to perform all the software processing by the MPU.

When the power is turned on, the value is not latched in the lunch 104, and dR may have a large value.
Before turning off the power, back up the previous value with a battery,
Processing such as latching the value when the power is turned on is required.

Second Embodiment FIG. 4 shows the configuration of a second embodiment of the present invention. In the present embodiment, an adder / subtractor 110,
The output unit of the erase control including the limiter 111 and the latch 112 is added, and other configurations are common and the description is omitted.

In the above configuration, the control operation of the image forming method of the present embodiment will be described in detail. In the present embodiment, the number of generated detection patterns is controlled by the output unit of the erase control, and the membership function for outputting the number of generated detection patterns is shown in FIG.
Table 2 shows the rules.

[0048]

[Table 2]

Here, when there are inputs of R = 0.475 and dR = 0.025, 5 g is output as the toner replenishment amount as in the first embodiment. On the other hand, since rules 2 and 3 among rules 1 to 17 are matched, the detection pattern interval is P for rules 2 and 3 and 0 for the others.
The combined output shown in (b) is obtained, and the defuzzy output +5 is obtained.

From this result, the value obtained by adding +5 to the previous detection pattern interval (contents of the latch 112) is added to the adder / subtracter 11.
Output from 0. For example, if the previous time is 10, the detection pattern interval is 15, and if the previous time is 13, the detection pattern interval is 18. However, the output of the adder / subtractor 110 is limited by the limiter 111 to a maximum value of 20 sheets and a minimum value to 5 sheets. Therefore, even if the adder / subtractor 110 outputs a value larger than 20 sheets or a value smaller than 5 sheets. , Latches 112 are stored as 20 or 5, respectively.

In such a place where the change is small, the detection pattern generation interval is lengthened to reduce the toner consumption, and in a place where the change is sharp, the detection pattern generation interval is shortened, thereby improving the control accuracy of the toner supply control. Can be planned. When the power is turned on, the detection pattern generation interval is
For example, it is necessary to set and latch 10 sheets.

Third Embodiment FIG. 6 shows a configuration of a third embodiment of the present invention. The present embodiment is different from the second embodiment in that latches 113 to 116 are provided.
, An averaging circuit 117, and a subtractor 118, and the other components are common and will not be described.

In the above configuration, the control operation of the image forming method according to the present embodiment will be described in detail. Compared with the second embodiment, the output of the fuzzy controller 106 is the same, and is obtained by adding iR to the input unit. This iR input latches each of the four R inputs up to that time with respect to the current R input, averages the values of R a total of five times, and calculates the difference between the value and the current value (current-average value) Is used.

FIG. 7 shows the membership function for iR input. Table 3 shows the rules. The concept of iR will be described with reference to the rules in Table 3. For example, when the value of R conforming to the rules 8 and 9 is medium and dR is NL (for example, the current R is 0.45 and the previous R is 0.6), in the second embodiment, the toner is replenished. Although stopped, in the present embodiment, when the average value so far is greater than the current value, that is, when the average value is medium or less, the above 0.6
Is regarded as an abnormal value, the rule 8 of the toner supply output is set to be small, and if the difference between the average values is N, that is, larger than the average value, it is determined that the toner consumption is abrupt (a sharp decrease). As in the second embodiment, the toner supply is stopped according to the rule 9. Thereby, control accuracy can be further improved.

[Table 3]

Although the rule is simplified by using the difference value for iR here, the average value itself can be input. In that case, And the same control can be performed.

Fourth Embodiment FIG. 8 is an explanatory diagram showing a configuration of an image forming apparatus using the image forming method according to the fourth embodiment.
Reference numeral denotes an image reading unit, and reference numeral 410 denotes an image forming unit that transfers image information read by the image reading unit to recording paper.

The image reading unit 400 includes a contact glass 401 on which a document is placed, and a light source 4 for irradiating the document placed on the contact glass 401 with light while moving.
02, a mirror 403 that moves together with the light source 402 and deflects the reflected light from the original, mirrors 404 and 405 that similarly deflect the reflected light from the mirror 103 in a predetermined direction, and focuses the reflected light from the mirror 405. A lens 406,
And a CCD 407 for reading light from the lens 406.

The image forming unit 410 rotates at a high speed and scans the laser beam at an equal angle, and the laser beam scanned at an equal angle by the polygon mirror 411 at equal intervals on the surface of the photosensitive drum 414. Lens 412 for correcting so that the laser beam from the mirror 41 guides the laser beam from the fθ lens 412 to the photosensitive drum 414.
3, a photosensitive drum 414 for forming an electrostatic latent image, a charging charger 415 for uniformly charging the surface of the photosensitive drum 414, and an exposure by a laser beam guided by a mirror 413 after charging by the charging charger 415. And a developing device 416 for visualizing the electrostatic latent image formed by the above.

A paper cassette 41 for storing recording paper of a predetermined size and detachably mounted on the apparatus main body.
7, 418, and a paper feed roller 417a that conveys the recording paper from the paper feed cassettes 417, 418 one by one toward the transfer unit.
418 a, a registration roller 419 for feeding the recording paper fed by the paper feed rollers 417 a and 418 a to the transfer unit at a predetermined timing, and an image on the photosensitive drum 414 with respect to the recording paper fed by the registration roller 419. And a transfer charger 421a for transferring the
A separation charger 421b for separating the recording paper from the photosensitive drum 414, and a fixing unit 422 for fixing the recording paper separated from the photosensitive drum 414 by the separation charger 421b.
Conveyor belt 420 for transporting in the direction, a fixing unit 422 for fixing the image on the recording paper after the transfer processing, a cleaning unit 423 for removing residual toner on the surface of the photosensitive drum 414 after the transfer processing, and a surface of the photosensitive drum 414 And a charge removing lamp 424 for removing the residual charges.

Note that reference numeral 425 denotes a paper feed cassette 417, 41
8, a humidity sensor for detecting humidity, a timer for detecting the paper feed interval of the recording paper, and a paper thickness sensor for detecting the thickness of the recording paper. Reference numeral 426 denotes PTL for performing pre-transfer exposure, and 427 denotes recording. A resistance value detection unit 428 for detecting the electric resistance value of the paper is a timer for integrating the use time of the transfer charger 421a and the separation charger 421b.

In this embodiment, the photosensitive drum 4
A reversal development system 14 uses a one-charged organic photoreceptor and uses a two-component developer containing a negatively-charged toner as a developer. Further, the lighting time of the laser beam is sequentially accumulated as an image forming signal by an accumulation counter 504 to be described later in order to determine a toner supply amount.

The operation of the above configuration will be described. First, in the image reading unit 400, the original placed on the contact glass 401 is illuminated by the light source 402, and the reflected light is read by the CCD 407 via the mirrors 403, 404, 405, and the lens 406. The image information read by the CCD 407 undergoes predetermined image processing and is emitted from a semiconductor laser (not shown) as a laser beam.

The laser beam is applied to the polygon mirror 411, f
The photosensitive drum 4 via the θ lens 412 and the mirror 413
It is led to 14. On the other hand, the photosensitive drum 414 has its surface uniformly charged in advance by a charging charger 415, and is exposed to the laser beam to form an electrostatic latent image. The surface potential of the photosensitive drum 414 at this time is usually background portion potential (dark potential) V _D of about -800 V, the image area potential (bright potential) V _L is set to about -100 V, developing bias potential V It is developed with a potential difference of about -600 V of _B. The electrostatic latent image formed on the photosensitive drum 414 is visualized by a developing device 416, and the visualized image is fed from paper feed cassettes 417, 418 to paper feed rollers 417a, 418.
a and the recording paper conveyed by the registration rollers 419 is transferred by the transfer charger 421a.

The recording paper on which the image has been transferred is separated from the photosensitive drum 414 by the separation charger 421b, conveyed by the transfer belt 420, enters the fixing unit 422, undergoes a fixing process, and is discharged outside the apparatus. After the transfer process is completed, the residual toner is removed from the photosensitive drum 414 by the cleaning unit 423, and the residual charge is removed by the charge removing lamp 424. Then, the photosensitive drum 414 enters a standby state in preparation for the next image forming process.

The PTL 426 shown in FIG. 8 is transferred to the photosensitive drum 41 by the transfer charger 421a before the transfer process.
By irradiating light on the photosensitive drum 4, excess charges on the photosensitive drum 414 are extinguished.

Here, the photosensitive drum 4 outside the image forming area
A detection pattern for controlling image density is formed on the sheet 14 once every 10 copies, and a reference image (developed by a reflective optical sensor disposed close to the photosensitive drum 414 and opposed thereto). detection signal voltage V _SG of the surface of the detection signal voltage V _SP and the reference image photosensitive drum 414 corresponding to the reflectivity of the detection pattern) is outputted, it is compared with the V _SP / V _SG corresponding to the image density of the aim Thus, the level of the image density is determined.

Referring to FIG. 9, a control flow according to the fourth embodiment will be described. Fuzzy controller 502
A, V _SP / V _SG value, and, when the difference between the previous V _SP / V _SG via the latch 501 is input, the fuzzy controller 502 infers the change degree of the toner supply amount per unit imaging signal Then, the toner supply amount per unit supply amount (here, the degree of change) is determined. The toner supply amount per unit image formation signal storage / readout unit 503 stores the toner supply amount per unit image formation signal according to the degree of change determined by the fuzzy controller 502. The image forming signal (lighting time of the laser beam) is stored in the integrating counter 50.
The toner replenishing clutch 5 is supplied to the toner replenishing clutch 5 so as to replenish the toner corresponding to the image forming signal based on the previously determined unit replenishing amount per unit replenishing amount.
05 is turned on and off.

Next, the inference process in the fuzzy controller 502 will be described below. Fuzzy controller 50
No. 2 quantifies the control rules expressed linguistically and can be replaced with actual numerical values. In other words, the inference result, and consequently the control ability, greatly changes depending on how the rules are created. Therefore, the method of expressing the control rules is very important, and it is necessary to appropriately select the parameters used here.

In the fourth embodiment, the future image density can be estimated by using the _VSP / _VSG of the optical sensor as the target image density and taking the history as information. The toner supply amount per unit image forming signal is switched in advance so that the image density always becomes a desired density. Note that the control target and the control amount are not a simple toner supply amount but a toner supply amount per unit image forming signal, so that the information amount of the image created between the visualized patterns (detection patterns) is obtained. (In other words, fluctuation of the control accuracy due to the toner consumption amount) is prevented, which is one factor that can greatly improve the control accuracy as compared with the case where the toner supply amount is simply set. .

Further, in the fourth embodiment, fuzzy inference is used for comprehensive inference, and the ambiguous concept of low image density is replaced with the expression that V _SP / V _SG of the optical sensor is low. Can be logically inferred, and these are expressed by linguistic rules as shown in Table 4.

The rule according to the fourth embodiment is composed of an antecedent part (if any) and a consequent part (hereinafter referred to as).

[Table 4]

These seven rules are shown in FIG.
By the membership functions shown in (b) and (c), they are quantitatively represented as fuzzy variables and can be operated. In the fourth embodiment, inference is performed using the above seven rules. However, the present invention is not particularly limited to this, and finer control can be performed by further increasing the number of rules. In the inference operation in the antecedent part, the degree of conformity of the antecedent part is obtained by taking the input value and the antecedent part variable MAX by inputting the input value and the antecedent part variable according to the usual method. MIN is taken as the conclusion of the rule. After obtaining respective conclusions for all given rules, MAX of all the conclusions is taken, and as a final inference result, toner supply per unit image forming signal to be targeted for the set Q / M The amount is obtained.

Here, concretely, an example of calculation in the case where V _SP / V _SG is a little low and the rate of change is a little + will be described.
The target replenishment amount is calculated by using 8. As shown in FIG. 11, for example, under the condition that V _SP / V _SG = 0.05 and the difference from the previous time = −0.075, rule 7
_SP / V _SG = 0.05 to calculate the point of intersection between the membership function that belong to each rule so that it is grade of 0.30 to a set of low moderate the V _SP / V _SG (belonging degree). Of these intersections, the minimum value (0 in Rule 7) is calculated to obtain a conclusion. After the conclusions are similarly obtained for all the rules, the MAX of all the conclusions is obtained by the combined output (the shaded portion in the figure) and the center of gravity is obtained to obtain the inference result (here, the toner per unit image forming signal). The degree of change in the supply amount: × 1.2) is obtained.

The toner supply amount per unit image forming signal is stored in the storage / readout unit 503, and is rewritten and determined based on the degree of change. For example,
Emission time of laser beam for 0.275 g / sec × 1.
2 determines the emission time of the laser beam for 0.33 g / sec. In the fourth embodiment, integration counter 5
The relationship between the rotation time of the toner supply roller and the toner supply amount is set to 0.3 g / sec as a ratio as an integration constant in 04, and the on / off time of the toner supply clutch 505 is 0.3 g / sec. And the toner supply amount per unit image forming signal, and the image forming signals are sequentially controlled by the integrated count.

Therefore, if the lighting time of the laser beam for 0.2 seconds is integrated, a total of 0.33 g /
1 sec × 0.2 sec ÷ 0.3 g / 1 sec = 0.2
By turning on the toner supply clutch for 2 seconds, 0.066 g of the required toner is supplied. Here, how many seconds the laser beam is turned on before replenishing the toner is optional depending on the system, but is set to 0.2 sec in the fourth embodiment.

By controlling in this manner, toner replenishment is performed at any time according to the amount of consumption, and the toner replenishment amount per unit image forming signal is fuzzy inferred so that the image density becomes constant for every 10 copies. Is used to finely correct the image density (or toner density) by using a conventional P sensor or toner density sensor.
It has good responsiveness to changes over time in the environment and the type of original, and can constantly control the image density to a desired density.

Further, by changing the fuzzy rules (inference rules), the present invention can be applied to the process control of an image forming apparatus of a different model. Further, as a secondary effect, the development period and the development cost can be reduced.

Fifth Embodiment An image forming apparatus used in a fifth embodiment is different from the image forming apparatus in that a toner density sensor is incorporated in a developing device so that a toner density (TC) can be detected at any time. Since this embodiment is the same as the fourth embodiment, illustration and description are omitted. Here, a toner density sensor (not shown) can take in average data every 0.5 sec.

The toner density sensor is of a type that outputs a change in magnetic permeability due to a change in toner density (hereinafter referred to as TC) as a change in voltage. By comparing the output voltage with respect to T.C. The level of C is determined.

Referring to FIG. 12, the flow of control in the fifth embodiment will be described. Fuzzy controller 514
In the target T. C memory reading unit 511, latch 51
T.2 and the difference calculation 513, C. difference from the target value of T.C. When the difference of C from the previous time is input, the fuzzy controller 514 infers the toner supply amount (here, the degree of change) for the unit image according to the value,
The toner supply amount per unit image formation signal storage / readout unit 517 stores the toner supply amount per unit image formation signal according to the degree of change determined by the fuzzy controller 514.

Image formation signal (lighting time of laser beam)
Is input to the integration counter 518 at any time, and based on the previously determined toner supply amount per unit supply amount, the timing for turning on and off the toner supply clutch 519 so that toner corresponding to the image forming signal is supplied. Controlled. Furthermore, through the latch 515 and the difference calculation 516, the difference between the target value of V _SP / V _SG, and, V _SP / V _SG
When the difference from the previous time is input, T.D. C
Change the target value of.

[0082] In the fifth embodiment, as representing the image density of a target, using a V _SP / V _SG of the optical sensor, by taking the history as information, depending on whether a state image stable , The target T. He is deciding whether to change C. This is because even though the image density is unstable, the target T.D. If C is changed, the final target image density may diverge without being focused on because the toner supply has a time delay. Also, the target T. The actual T.C. C, and T.C. By capturing the history of C as information,
Future T. C can be estimated, and T.C. The toner supply amount per unit image forming signal is switched in advance so that C is aimed. Here, the control target and the control amount are not simple toner supply amounts but toner supply amounts per unit image forming signal for the same reason as in the fourth embodiment.

Also, in the fifth embodiment, fuzzy inference is used for comprehensive inference, and the ambiguous concept of low image density is replaced with the expression that V _SP / V _SG of the optical sensor is low. Can be reasoned logically, and these are expressed as shown in Table 5 by linguistic rules.

The rule according to the fifth embodiment is composed of an antecedent part (if any) and a consequent part (hereinafter referred to as).

[Table 5]

These ten rules are quantitatively represented as fuzzy variables by a membership function as shown in FIG. 13 and can be operated. Here, specifically, if T.S. C was 1.5% against 2% of the target, and T.C.
When the degree of change of the toner supply amount per unit image forming signal when the difference from C is -0.5% is calculated,
1.2. By performing the same calculation for V _SP / V _SG , the target T.V. C can be corrected. The subsequent rotation control method of the toner supply roller is the same as in the fourth embodiment.

By controlling in this manner, the relationship between the image density (V _SP / V _SG ) and the toner supply amount per unit image forming signal shown in the fourth embodiment is further improved.
Embodiment 4 Introduces always detectable parameters such as toner density and image forming signal, and finely corrects and controls these relationships using fuzzy inference.
In addition to the effect described above, the number of times the P sensor pattern is created can be reduced.

In the fifth embodiment, V _SP / V _SG
Alternatively, the user can use the input means as shown in FIG. The rules 8 to 10 in this case are as shown in Table 6. The input here is performed for each copy.

[0088]

[Table 6]

For these membership functions,
This is the same as _VSP / _VSG . In this way, by introducing the ambiguous information that the user input is dark or light in the membership function, the ambiguity can be digitized and appropriately controlled.

[Sixth Embodiment] In the sixth embodiment, a device provided with a temperature / humidity sensor and a photoconductor operating time counter is used instead of the optical sensor in the fifth embodiment. The control flow will be described with reference to FIG. In the sixth embodiment, fuzzy inference is used for comprehensive inference. Fuzzy controller 520
When the temperature and humidity from the temperature and humidity sensor and the operation counter of the developing device are input, fuzzy inference is performed according to the values, and the target T.D. Output C. Difference calculation 522
Is the target T. C, current T.C. C and latch 52
1 through the previous T. C. Enter T. The difference from C and the rate of change of this difference are output. The fuzzy controller 523 has a T.D. Inference is performed on C, and the toner supply clutch 526 is controlled via the storage / readout unit 524 of the toner supply amount per unit time and the integration counter 525.

In general, a two-component developer used in an electrophotographic system deteriorates with time, so that the CA (carrier charging ability) is reduced. Further, even under the environmental conditions around the developer, there is a phenomenon that Q / M increases due to an increase in charge accumulation at low temperature and low humidity, and Q / M decreases due to an increase in charge leakage at high temperature and high humidity. Therefore, in the present embodiment, by developing these relationships into rules, the developing capability of the developing device is predicted and controlled without an optical sensor. That is, the deterioration of the developer over time is predicted from the operation counter of the developing device, the variation of Q / M in the environmental conditions around the developer is predicted by the temperature and humidity sensor, and the developing capability of the developing device can be controlled. The toner density is the same as in the fifth embodiment.

Next, Tables 7 and 8 show rules of inference in the sixth embodiment. The rule according to the sixth embodiment includes an antecedent part (if it is) and a consequent part (it is assumed).
, Rules 10 to 16 belong to the fuzzy controller 523.

[0093]

[Table 7]

[0094]

[Table 8]

These 16 rules are quantitatively represented as fuzzy variables by a membership function as shown in FIG.
6 is the same as that in FIG. 13). Here, specifically,
If the operation time of the developing device is 80 hours and the temperature and humidity are 2
The target T.V. When C is calculated, it becomes 3%. The toner supply amount per unit image forming signal is the same as in the fifth embodiment. Further, the subsequent rotation control of the toner supply roller is the same as that of the fourth embodiment, and thus the description is omitted.

By controlling in this way, the optical sensor in the fifth embodiment can be omitted. For this reason, it is possible to prevent wasteful toner consumption due to creation of the detection pattern, load on the cleaning device, reduction in copy speed, and the like.
In the sixth embodiment, it is of course possible to use a combination of optical sensors in the same manner as in the fifth embodiment. The effect in this case is that the surface potential of the photoconductor varies depending on the number of sheets used or the like. Even in such a case, the image density can be maintained at a desired density even if the number of times of forming the optical sensor is reduced as compared with the related art.

[Seventh Embodiment] The configuration of an image forming apparatus according to a seventh embodiment is the same as that shown in FIG. 8 (similar to that of the fourth embodiment). The details are omitted, but the agitator in the toner hopper in the developing device is omitted. It is assumed that the torque applied to can be measured. This agitator torque changes depending on the toner capacity in the hopper. The rotation speed of the toner supply roller can be freely changed from the main control plate of the main body. As apparent from the configuration of FIG. 8, the number of rotations of the toner supply roller does not directly affect the agitator torque, and fuzzy inference is used for comprehensive inference.

In an image forming apparatus of a type in which toner is replenished by rotation of a toner replenishing roller, as shown in FIG. 17, the actual amount of supplied toner varies depending on the remaining amount of toner in the hopper at the same rotational speed. Therefore, in the seventh embodiment, the relationship between the rotation time of the toner supply roller and the toner supply amount is always maintained at 0.3 g / sec by performing fuzzy control of the rotation number of the toner supply roller based on the agitator torque. By setting to
This is to solve this problem.

Referring to FIG. 18, a control flow in the seventh embodiment will be described. In the seventh embodiment, the fuzzy controller 530 sets the agitator torque (that is, the remaining amount of toner in the hopper) every five seconds together with the difference from the previous value.
, And is subjected to fuzzy inference to determine the rotation control amount of the toner supply roller.

The reason why the number of rotations of the toner supply roller is changed is to keep the toner supply amount per unit image forming signal constant. Therefore, the toner remaining amount is indirectly measured by the agitator torque. The rotation speed of the toner supply roller is controlled so that the actual toner supply amount is constant. These control rules can be expressed as shown in Table 9.

[0101]

[Table 9]

For all these five rules, FIG.
A membership function as shown in FIG. 9 is created, estimated, and a correction amount is determined. For example, if the agitator torque is 5
When 0 kg / cm ² and the difference from the previous time are −5 kg / cm ² , the rotation speed of the toner supply roller is estimated to be 205 RPM.

By using such a method, the desired amount of toner can be maintained even when the remaining amount of toner in the toner hopper is small. In the seventh embodiment, the number of rotations of the toner supply roller is changed. However, the toner supply time may be extended.

Eighth Embodiment An image forming apparatus according to an eighth embodiment is similar to the image forming apparatus according to the fourth embodiment.
The configuration is such that the development bias condition can be changed by a known method. This independently of the developing device, by changing the developing potential (V _L -V _B), it is possible to change the actual amount of development. In Embodiment 8, maintained even fallen developing ability for developing potential aim of developing devices compensate by changing the development potential and the reduction amount (V _L -V _B), the amount of development aimed (image density) Is what you do.

In the apparatus for replenishing toner based on the image forming signal as described in the above-described fourth to sixth embodiments, the target T.V. If C (toner density) has not been reached, the difference can be predicted from the remaining toner replenishment signal that has not been replenished. The eighth embodiment utilizes this, and shows the control flow of FIG. Fuzzy inference is used for comprehensive inference,
The remaining (total count) of the toner supply signal from the toner supply signal integration counter 540 is
42, the fuzzy controller 542
Fuzzy inference is performed according to the amount, and a control destination and a control amount are determined.

Here, as the control destination, the developing bias 54
3, the charge exposure 544 (or more than two) is basically desirable to change the developing bias 543 because the corresponding speed is faster, but the changeable range is limited. It is necessary to change the control destination according to the required development potential. The toner replenishment signal is accumulated and counted as needed, an appropriate toner replenishment signal is output, and the toner replenishment clutch 541 is turned on and off. In the eighth embodiment, based on the count value, fuzzy inference is performed in accordance with a replenishment time signal, a control destination is determined, and control is performed.

After the image signal of one frame is output (after exposure), the control destination other than the toner replenishment is inferred by the rule shown in Table 10 based on the difference between the remaining total count and the previous value. , A developing bias, a grid, and exposure conditions are selected for control. This correction is reset every time, and the initial state (V _D = −800 V,
V _L = -50 V, return to V _B = -600V), which is controlled again by the inference result.

[0108]

[Table 10]

For all these six rules, FIG.
A membership function as shown in (1) is created, estimation is performed, and a control destination and a control amount are determined. For example, the integrated total count value (that is, the replenishment time of the toner that has not been replenished) is 20 sec, and the difference from the previous time is −1 s.
ec, the developing bias is set to -100 from the set value.
V plus -50V + 150V in total, exposure amount +10
By increasing by 0 V, the target T. This prevents the image density from lowering by the amount of toner that cannot be supplied to C.

Here, it is needless to say that the potential difference between the charging potential and the developing bias is kept at a certain level or more to prevent carrier adhesion. As a result, even when an image having a large image area is taken, or even in a condition such as toner near end where toner replenishment cannot follow and the image density decreases, the image density is temporarily reduced to a desired density. Can be kept. Although the fourth to eighth embodiments can be used independently, they can also be used in combination. The effect of the combination is shown in FIG. 22 in comparison with the conventional control of only detection by an optical sensor.

Ninth Embodiment An image forming apparatus according to a ninth embodiment is the same as that of the fourth embodiment, and a description and illustration thereof will be omitted. FIG. 23 shows a control flow according to the ninth embodiment. As shown in FIG.
50, integration counter 552, and A / B calculation unit 55
1 to the fuzzy controller 554 by _VSP /
V _SG, when a value of the accumulated value of the image forming signals between the (V previous value of the _{SP / V SG -V SP / V} SG) / previous detection pattern is input, the fuzzy controller 554 with the value Accordingly, the degree of change of the toner supply amount per unit image formation signal is inferred, and the toner supply amount per unit image formation signal stored in the toner supply amount storage / readout unit 555 per unit image formation signal is determined. The image forming signal is input to the integration counters 552 and 553 as needed and integrated. Here, the count value of the integration counter 552 is read out when the detection pattern is created, and reset at the same time.

When the count value of the integrating counter 553 reaches a certain value, the count value is output to the control signal generator 556. The control signal generation unit 556 supplies toner based on the previously determined toner supply amount per unit image forming signal so as to supply toner corresponding to the integrated value of the image forming signal (laser beam lighting time). By controlling the timing at which the clutch 557 is turned on and off, toner supply is performed.

Here, as the control object and the control amount, not the simple toner supply amount but the toner supply amount per unit image forming signal is used, and the history information is also a simple V _SP / V.
_SG - rather than the previous _{V SP / V SG, (V} SP / V SG -V SP / V
_By setting the integrated value of the image formation signal between the previous value of _{SG and} the previous detection pattern, the control accuracy is prevented from fluctuating due to the image taken between the detection patterns, and simple toner supply The control accuracy can be greatly improved as compared with the case where the amount or the simple _VSP / _VSG -the previous _VSP / _VSG is used. Further, it is needless to say that this history information can be used not only in the last time but also in the value two or more times before.

These control rules can be expressed as shown in Table 11.

[Table 11]

These seven rules are shown in FIG.
It is quantitatively represented as a fuzzy variable by a membership function as shown in (b) and (c). Here, specifically, if V _SP / V _SG is a little low and the difference from the previous time / the rate of change of the integrated value of the image forming signal is a little +, an example of calculation will be shown. By
The target supply amount is calculated from the rules 1 to 7 described above. FIG.
As shown in the above, for example, under the condition that V _SP / V _SG = 0.05 and the difference from the previous time / the integrated value of the image forming signal = −0.075, in rule 7, V _SP / V _SG = 0 .05
Is such that it is grade of 0.30 to a set of low moderate the V _SP / V _SG, to calculate the point of intersection between the membership function that belong to each rule. The smallest value (0 in rule 7) of the intersections is calculated to obtain a conclusion.

After similarly obtaining conclusions with respect to all rules, all MAXs are taken (shaded portions), and the center of gravity is obtained to obtain an inference result (in this case, the degree of change of the toner supply amount per unit image forming signal: × 1.2) is obtained. The toner supply amount per unit image forming signal is stored in the storage / readout unit 555, and is rewritten and determined based on the degree of change. In the ninth embodiment, the ratio between the rotation time of the toner supply roller and the amount of toner supply is 0.3 g / sec as the integration constant in the integration counter.
c, the toner supply clutch 557 is turned on,
The OFF time is sequentially controlled by an amount obtained by integrating and counting the image forming signal (the laser beam lighting time) based on this value and the toner supply amount per unit image forming signal.

Therefore, if the lighting time of the laser beam for 0.2 seconds is integrated, a total of 0.3 g / s is obtained.
ec × 0.2 sec ÷ 0.3 g / sec = 0.22 sec
By turning on the toner replenishment clutch 557 during the period c, 0.066 g of the required toner is replenished. here,
When the lighting time of the laser beam reaches a certain number of seconds, the data of the integrating counter 553 is output to the control signal generator 556 to replenish the toner.
In Embodiment 9, the time is set to 0.2 sec.

By performing control in such a manner,
Toner replenishment is performed as needed in accordance with the consumption amount, and the toner replenishment amount per unit image forming signal is finely corrected using fuzzy inference so that the image density becomes constant every ten copies. Compared to the control of the image density (or toner density) by the P sensor or the toner density sensor, the control is performed so that the image density (or toner density) is better than the control over the aging environment, the responsiveness to the document type, and the follow-up property. It becomes possible.

Embodiment 10 The image forming apparatus used in Embodiment 10 is different from the image forming apparatus in that a toner density sensor is incorporated in the developing device so that the toner density (TC) can be detected at any time. Since this embodiment is the same as the fourth embodiment, illustration and description are omitted. Here, average data excluding the data at the start of the copy operation is taken in every other copy.

The toner density sensor is of a type that outputs a change in magnetic permeability due to a change in toner density (hereinafter, referred to as TC) as a change in voltage. By comparing the output voltage with respect to T.C. The level of C is determined.

Referring to FIG. 26, the flow of control in the tenth embodiment will be described. The target T. Through the C memory readout unit 560, the latch 561, the integration counter 563, and the A / B calculation unit 562, the target T.C. C. value and T.C. When the difference between C and the previous time is input to the fuzzy controller 569, the fuzzy controller 5
69 infers a toner supply amount per unit image forming signal according to the value, and stores and reads out a toner supply amount per unit image forming signal storage unit 570, a control signal generation unit 571,
Further, the rotation of the toner supply roller is controlled via the toner supply clutch 572.

At this time, when the control signal generator 571 receives the integration count output from the integration counter 564, it outputs a signal corresponding to the toner supply amount per predetermined unit image forming signal to the toner supply clutch 572. Further, a latch 566, an integration counter 565, and D /
When the difference between the target value of V _SP / V _SG and the difference of V _SP / V _{SG from} the previous value is input to the fuzzy controller 568 via the E operation V _SP / V _SG 567, the fuzzy controller 568 Depending on the value, the target T. Change C.

Next, Table 12 and Table 13 show rules of inference in the ninth embodiment. The rule according to the ninth embodiment includes an antecedent part (if any) and a consequent part (hereinafter, “rule”).
9, and rules 8 to 10 are for the fuzzy controller 568.

[0124]

[Table 12]

[0125]

[Table 13]

These ten rules are quantitatively represented as fuzzy variables by a membership function as shown in FIG. 27 and can be operated. Here, specifically, if T.S. C was 1.5% against 2%, the previous T.C. When the difference from C is -0.5% and the integrated value of the image forming signal (the emission time of the laser beam in this case) is 1 second, the toner supply amount per unit image forming signal is calculated. Then, it becomes × 1.2. By performing the same calculation for V _SP / V _SG , the target T.V. C can be corrected. The subsequent control method of the toner supply roller is the same as that of the ninth embodiment, and the description is omitted.

By controlling in this manner, the relationship between the image density (V _SP / V _SG ) and the image forming method according to the ninth embodiment can be constantly detected as the toner density and the image forming signal. Since these parameters are finely corrected and controlled using fuzzy inference by introducing various parameters, in addition to the effect of the ninth embodiment, it is possible to further reduce the number of generations of the detection sensor pattern. it can.

[Eleventh Embodiment] In the eleventh embodiment, a device provided with a temperature / humidity sensor and a photoconductor operating time counter is used instead of the optical sensor in the tenth embodiment. Referring to FIG.
The control flow will be described. In the eleventh embodiment, fuzzy inference is used for comprehensive inference. Fuzzy controller 5
When the temperature and humidity from the temperature and humidity sensor and the operation counter of the developing device are input, fuzzy inference is performed according to the values, and the target T.80 is used. Output C. The target T. C
The storage and reading unit 581 outputs the target T.D. The difference from C is output.

On the other hand, the fuzzy controller 582 controls the target T.D. C, the difference from T.C. C and the rate of change (TC
And the previous T. C.) is divided by the integrated value of the image forming signal. C inference and storage / readout section 58 of toner supply amount per unit image forming signal
7. The toner supply clutch 589 is controlled via the control signal generator 588. The A / B operation unit 586 includes a latch 58
3 and the integration counter 584, the change rate (difference between TC and the previous TC) and the integrated value of the image forming signal are input, and the change rate per unit image forming signal is obtained. Also,
When inputting the integration count output from integration counter 585, control signal generating section 588 outputs a signal corresponding to the toner supply amount per predetermined unit image forming signal to toner supply clutch 589.

In general, a two-component developer used in an electrophotographic system deteriorates with time, so that CA (charging ability of a carrier) decreases. Further, even under the environmental conditions around the developer, there is a phenomenon that Q / M increases due to an increase in charge accumulation at low temperature and low humidity, and Q / M decreases due to an increase in charge leakage at high temperature and high humidity. Therefore, in the present embodiment, by developing these relationships into rules, the developing capability of the developing device is predicted and controlled without an optical sensor. That is, the deterioration of the developer over time is predicted from the operation counter of the developing device, the variation of Q / M in the environmental conditions around the developer is predicted by the temperature and humidity sensor, and the developing capability of the developing device can be controlled. Note that the toner density is the same as in the tenth embodiment.

Next, Table 14 and Table 15 show inference rules in the eleventh embodiment. Rule 1 to Rule 9
Is for the fuzzy controller 580, and rules 10 to 16 are for the fuzzy controller 582.

[0132]

[Table 14]

[0133]

[Table 15]

These 16 rules are quantitatively expressed as fuzzy variables by a membership function as shown in FIG. 29 and can be operated (however, rules 10 to 16 are used).
Is not shown because it is the same as FIG. 27). Here, specifically,
If the operation time of the developing device is 80 hours and the temperature and humidity are 2
The target T.V. When C is calculated, it becomes 3%. The toner supply amount per unit image forming signal is the same as in the tenth embodiment.

By controlling in this way, the optical sensor in the tenth embodiment can be omitted. For this reason, it is possible to prevent wasteful toner consumption due to creation of the detection pattern, load on the cleaning device, reduction in copy speed, and the like. In the eleventh embodiment, it is of course possible to use a combination of optical sensors in the same manner as in the tenth embodiment. The effect of this case is that the surface potential of the photoconductor varies depending on the number of sheets used or the like. Even in such a case, the image density can be maintained at a desired density even if the number of times of forming the optical sensor is reduced as compared with the related art.

[Embodiment 12] An image forming apparatus used in Embodiment 12 is basically the same as the image forming apparatus used in Embodiment 4, so that illustration and description are omitted, and different parts will be described. Add. In the twelfth embodiment, a toner density sensor is incorporated in the developing device so that the toner density (TC) can be detected at any time, so that average data can be captured every 0.5 sec. As a toner density sensor, T.V. C is used to output a change in magnetic permeability due to a change in voltage as a change in voltage. By comparing the output voltage with respect to T.C. The level of C is determined.

Further, the motor driving the developing device generates a pulse in accordance with the rotation, and the total number of rotations can be detected by the counter, whereby it is possible to know how much the developer has been stirred. .

Further, as shown in FIG. 30B, the discharge duct of the developing device at the position shown in FIG.
A relative humidity sensor (temperature and humidity sensor) is built in,
The relative humidity of the developing device can be determined. In order to detect the environmental condition of the developer atmosphere, it is desirable to directly measure the environment inside the developing device. However, if a sensor is provided inside the sensor, the sensor will become dirty with the toner, making accurate measurement impossible. By measuring the air after passing through the filter of the exhaust pressure duct, the internal environment of the developing device is accurately measured without being contaminated with toner.

FIG. 31 shows a structure of a process control apparatus according to the twelfth embodiment. In the twelfth embodiment, the stress detecting section 59 applied to the developer is classified according to the factors that cause the developing capability to fluctuate.
0, an environmental condition detecting unit 591 and a toner density transition detecting unit 592, which are obtained by combining membership functions, respectively, as input information. Estimate developing capacity or developing capacity in the near future. The control destination and control amount determination unit 594 determines a control destination and a control amount based on the estimation result. Further, a charging control unit 595, an exposure control unit 596, and a control unit that perform control based on the determined control amount.
There are a developing bias control unit 597 and a toner supply clutch control unit 598.

FIGS. 32 (a), 32 (b) and 32 (c) show membership functions for determining the effect on the developing ability of each detection unit. VS, MS, MM, M in the figure
L and VL are Very Small, Medium Small, and Med, respectively.
ium, Medium Large and Very Large.

FIG. 32A shows a membership function of the stress detecting section 590 applied to the developer, and its inference rules are as shown in Tables 1 to 5.

[Table 16]

FIG. 32 (b) shows the membership function of the development detecting section 591. The inference rules are as shown in Tables 17 to 10.

[Table 17]

FIG. 32C shows the toner density transition detecting section 59.
2 are shown in Table 1.
The rules 11 to 35 shown in FIG.

[Table 18]

Here, as an example, the inference process of the stress detector 590 applied to the developer will be described. For example, the total rotation time of the developing device required for the developer to reach its life is 1
If the total rotation time is 55% in the case of 00%, the antecedent part is subject to two rules 3 and 4 belonging to MM and MS as shown in FIG. Rules 3 and 4
Accordingly, a shaded portion of the consequent portion corresponding to the developing capacity change amount is inferred. Similarly, the relative humidity of 85 (RH%), the toner density of 1.75 (%), and the change in the developing capacity when the difference from the previous value of the toner density is 0 are also inferred. When there are two or more parameters in a block divided by one variation factor as in the case of MIN-M, a well-known fuzzy inference method is used in the block.
AX synthesis is in progress.

Next, as shown in FIG. 33, the total amount of change in the developing ability is represented by a single membership function by MAX combining the inference results obtained by the respective detection units.
By defuzzifying (obtaining the center of gravity) the hatched portion, a specific change amount is inferred. By calculating the center of gravity, a change in developing ability = -12% is obtained. In the twelfth embodiment, this value continuously decreases to -35% or less.
When the inference is made, "toner end" is displayed, the apparatus is stopped, and the apparatus is set in a toner supply standby state.

The obtained change in the developing ability is easily converted to the developing ability (mg / cm ² ) by giving an initial set value of the developing ability (target value at the time of design). Here, the initial set value is 0.7 (mg / cm ² ), and the developing ability is 0.6 based on the above-mentioned inference result (developing ability change amount = −12%).
2 (mg / cm ² ).

Next, a control destination and control amount determination section 594
Will be described. The developing ability obtained so far indicates the amount of adhesion on the photoconductor when the solid black is developed with respect to the initial target developing potential. Therefore, the developing ability and the image density have a close relationship as shown in FIG. 34, and based on the determined developing ability,
By changing the latent image forming condition and the developing bias condition in addition to the toner replenishing condition, the target image density can always be maintained.

Here, the reason why the development potential is changed by changing not only the toner replenishing amount but also the latent image forming condition and the developing bias condition is that the control of only the toner replenishment has a considerable delay in the response time. In such a case, an original having a large image forming area may be continuously copied, or the amount of toner may be reduced, so that an intended replenishment amount may not be obtained. In such a case, the image density can be stably controlled. That's why.

Note that these controls, except for the toner supply amount control, are performed based on the control amounts determined only when the scanner detects the leading edge of the image on the document, and the control amounts are changed during image formation. It will not be done. This prevents a sudden change in image density during image formation. In addition, since there is a considerable delay in the response time of toner supply, it is of course desirable to control the toner supply as soon as possible.

FIG. 35 shows a control destination and control determining section 594.
The upper part (development ability inference result) is the antecedent part, the lower part is the consequent part, and the lower part is the consequent part.
It is inferred according to the rules shown in Table 19 below. In addition,
Determined control amount is reset each time, in the initial state (embodiment _{12, V D = -800V, V} L. = -50V,
Returning to V _B = -600V), so that the next time is controlled again by the inference result.

[0151]

[Table 19]

For example, when the developing capacity is 0.7 (mg / cm
² ), as is clear from FIG. 35, the antecedent part has eight rules (rules 45 to 45) belonging to MS and MM.
52). According to this rule, the hatched portion (see FIG. 35) of the consequent corresponding to each control destination is inferred. The control amount is determined for each of these by determining the center of gravity.
Here, grid control amount: +65 V, exposure control amount: +
65 V, a developing bias control amount: +65 V, and a toner replenishment control amount: + 20%. The control amount thus obtained is converted into an actual control value corresponding to an inference result based on the initial control value initially set in each control unit, and control is performed.

[Thirteenth Embodiment] In the image forming apparatus according to the thirteenth embodiment, in addition to the apparatus according to the twelfth embodiment, the membership on the photoreceptor outside the image forming area is once every 50 copies. A detection pattern for function correction is formed, and a detection signal voltage V _SP according to the reflectance of the detection pattern is provided by a reflection-type optical sensor disposed close to and facing the photoconductor, and no detection pattern is provided. (i.e., no image) detection signal voltage V _SG of the photoreceptor surface are output, and determines the level of developability.

FIG. 36 shows the relationship between V _SP / V _SG and the developing ability. As shown in the figure, there is a close relationship between the development capacity and V _SP / V _SG. Therefore, in the thirteenth embodiment, in addition to the method of the twelfth embodiment, the developing ability inference result is corrected according to the value of V _SP / V _SG .

FIG. 37 shows the structure of the process control apparatus according to the thirteenth embodiment. In the thirteenth embodiment, the stress detecting unit 60 applied to the developer for each of the factors that cause the developing capability to fluctuate.
0, an environmental condition detecting unit 601 and a toner density transition detecting unit 602, each of which is obtained by combining membership functions from the three detecting units, as input information. The developing capability or the developing capability in the near future is inferred, and the _VSP / _VSG value from the developing density detector 603 using the optical reflection density sensor is input to correct the inference result. The control destination and control amount determination unit 605 determines the control destination and the control amount based on the corrected inference result. Further, the charging control unit 606 and the exposure control unit 6 that perform control based on the determined control amount.
07, a developing bias control unit 608, and a toner supply clutch control unit 609.

FIG. 38 shows the membership function for inferring the developing ability from V _SP / V _SG , and Table 20 shows the rules.

[0157]

[Table 20]

For example, when V _SP / V _SG is 0.1, as can be seen from FIG. 38, the developing ability is inferred to be -15%.
Next, the result of inferring the developing ability at the time of pattern creation is V _SP
The scale is slid (corrected) to a value (−15%) determined by / V _SG , and the result is output based on the scale from the next inference. By controlling in this way, the inference result of the developing ability can be corrected by the actual amount of adhesion, and the developing ability can be controlled by absorbing the potential fluctuation due to the deterioration of the photoconductor. FIG. 39 shows a comparison between the conventional method and the present embodiment with respect to the stability of the image density.

[Fourteenth Embodiment] The image forming apparatus used in the fourteenth embodiment is the same as that of the fourth embodiment, so that illustration and description thereof will be omitted. However,
In the fourteenth embodiment, a toner density sensor is incorporated in the developing device so that the toner density (TC) can be detected at any time, and average data is taken in every 1.0 sec.

FIG. 40 shows the structure of the process control apparatus according to the fourteenth embodiment. According to the fourteenth embodiment, members are classified into three members, a long-term factor detecting unit 610, a medium-term factor detecting unit 611, and a short-term factor detecting unit 612, for each of the speeds that affect the factors that change the developing ability. The synthesis result of the ship function is used as input information. Based on the input information, the developing capability estimating unit 613 estimates the current developing capability or the developing capability in the near future. The control destination and control amount determination unit 614 determines a control destination and a control amount based on the estimation result. Further, the charging control unit 615 and the exposure control unit 61 for performing control based on the determined control amount.
6, a developing bias controller 617, and a toner supply clutch controller 618.

Next, the contents of the inference in the fourteenth embodiment will be described in detail. In the fourteenth embodiment, the detection unit has a temporal range in which the influence on the developing ability is changed, and includes a long term (unit of several days), a medium term (unit of several hours), and a short term (unit of several minutes). The detection unit 610 includes:
There is a counter for the total number of rotations of the developing device as a detection target,
A change in developing ability due to deterioration of the developer is detected. The medium-term factor detection unit 611 has a relative humidity sensor as a detection target, and detects a change in developing ability due to a change in relative humidity. In addition, the short-term factor detection unit 612 has a toner density sensor as a detection target, and detects a change in developing ability due to a change in toner density. However, the detection target is not particularly limited to this, and any detection target may be used as long as the time range that affects the developing ability is classified into a long term, a medium term, and a short term.

FIGS. 41 (a), 41 (b) and 41 (c) show membership functions for determining the influence on the developing ability of each detection unit. FIG. 41A shows the membership function of the long-term factor detection unit 610, and its inference rules are as shown in Tables 1 to 5 in Rules 1 to 5.

[Table 21]

FIG. 41B shows a membership function of the medium-term factor detection unit 611, and its inference rules are as shown in Tables 6 to 10 in Rules 6 to 10.

[Table 22]

FIG. 41 (c) shows the membership function of the short-term factor detection unit 612, and its inference rules are as shown in rules 11 to 35 shown in Table 23.

[Table 23]

Here, as an example, the long-term factor detection unit 61
The inference process of 0 will be described. For example, assuming that the total rotation time of the developing device required to reach the life of the developer is 100%, and the total rotation time is 55%, FIG.
As shown in (a), the antecedent part is subject to two rules 3 and 4 belonging to MM and MS. According to these rules 3 and 4, a consequent hatched portion corresponding to the developing capability change amount is inferred.
Similarly, a relative humidity of 85 (RH%) and a toner concentration of 1.75
(%), The developing capability change amount when the difference from the previous value of the toner density is 0 is also inferred.
When there are two or more parameters in a block divided by one variation factor as in the above, a known MIN-MAX combination is performed as a fuzzy inference method in the block.

Next, as shown in FIG. 42, the total amount of change in the developing ability is represented by a single membership function by MAX combining the inference results obtained by the respective detection units.
By defuzzifying (obtaining the center of gravity) the hatched portion, a specific change amount is inferred. By calculating the center of gravity, a change in developing ability = -12% is obtained. In the fourteenth embodiment, this value is continuously reduced to −35% or less.
When the inference is made, "toner end" is displayed, the apparatus is stopped, and the apparatus is set in a toner supply standby state.

The obtained change in the developing ability is easily converted to the developing ability (mg / cm ² ) by giving an initial set value of the developing ability (target value at the time of design). Here, the initial set value is 0.7 (mg / cm ² ), and the developing ability is 0.6 based on the above-mentioned inference result (developing ability change amount = −12%).
2 (mg / cm ² ).

Next, the control destination and control amount determination unit 614
Will be described. The developing ability obtained so far indicates the amount of adhesion on the photoconductor when the solid black is developed with respect to the initial target developing potential. Therefore, the developing ability and the image density have a close relationship as shown in FIG. 43, and based on the determined developing ability,
By changing the latent image forming condition and the developing bias condition in addition to the toner replenishing condition, the target image density can be always maintained.

The reason why the development potential is changed by changing not only the toner supply amount but also the latent image forming condition and the developing bias condition is that the control of only the toner supply causes a considerable delay in the response time. In such a case, an original having a large image forming area may be continuously copied, or the amount of toner may be reduced, so that an intended replenishment amount may not be obtained. In such a case, the image density can be stably controlled. That's why.

Note that these controls, except for the toner replenishment amount control, are performed based on the control amounts determined only when the scanner detects the leading edge of the image on the document, and the control amounts are changed during image formation. It will not be done. This prevents a sudden change in image density during image formation. In addition, since there is a considerable delay in the response time of toner replenishment, it is of course desirable to control the toner supply as soon as possible.

FIG. 44 shows a control destination and a control decision unit 614.
The upper part (development ability inference result) is the antecedent part, the lower part is the consequent part, and the lower part is the consequent part.
It is inferred according to the rules shown in Table 24 below. In addition,
The determined control amount is reset every time, and the initial state (in the fourteenth embodiment, V _D = −800 V, V _L. = −50 V,
Returning to V _B = -600V), so that the next time is controlled again by the inference result.

[0172]

[Table 24]

For example, when the developing capacity is 0.7 (mg / cm
^When it is inferred that ² ), as is apparent from FIG. 44, the antecedent part has eight rules (rules 45 to 45) belonging to MS and MM.
52). According to this rule, a hatched portion (see FIG. 44) of the consequent portion corresponding to each control destination is inferred. The control amount is determined for each of these by determining the center of gravity.
Here, grid control amount: +65 V, exposure control amount: +
65 V, a developing bias control amount: +65 V, and a toner replenishment control amount: + 20%. The control amount thus obtained is converted into an actual control value corresponding to an inference result based on the initial control value initially set in each control unit, and control is performed.

[Embodiment 15] In the image forming apparatus of the embodiment 15, in addition to the apparatus of the embodiment 14, the photoreceptor outside the image forming area has membership once every 50 sheets. A detection pattern for function correction is formed, and a detection signal voltage V _SP according to the reflectance of the detection pattern is provided by a reflection-type optical sensor disposed close to and facing the photoconductor, and no detection pattern is provided. (i.e., no image) detection signal voltage V _SG of the photoreceptor surface are output, and determines the level of developability.

As shown in FIG. 36, there is a close relationship between V _SP / V _SG and the developing ability. Therefore, Embodiment 15
In the embodiment, in addition to the method of the fourteenth embodiment, correction of the result of inferring the developing ability is performed according to the value of V _SP / V _SG .

FIG. 45 shows the structure of the process control apparatus according to the fifteenth embodiment. In the fifteenth embodiment, the factors that change the developing capacity are classified into three types, namely, a long-term factor detection unit 620, a medium-term factor detection unit 621, and a short-term factor detection unit 622, according to the speed at which the factors are affected. The synthesized result of the ship function is used as input information. Based on the input information, a developing capability estimating unit 621 infers a current developing capability or a developing capability in the near future, and further detects a developing density by an optical reflection density sensor. V _SP / V from section 623
Enter the _SG value to correct the inference result. The control destination and control amount determination unit 625 determines, based on the inference result after the correction,
Determine the control destination and the control amount. Further, there are a charge control unit 626, an exposure control unit 627, a developing bias control unit 628, and a toner replenishment clutch control unit 629 that perform control based on the determined control amount.

FIG. 46 shows a membership function for inferring the developing ability from V _SP / V _SG , and Table 25 shows its rules.

[0178]

[Table 25]

For example, when V _SP / V _SG is 0.1, as can be seen from FIG. 46, the developing ability is inferred to be -15%.
Next, the result of inferring the developing ability at the time of pattern creation is V _SP
The scale is slid (corrected) to a value (−15%) determined by / V _SG , and the result is output based on the scale from the next inference. By controlling in this way, the inference result of the developing ability can be corrected by the actual amount of adhesion, and the developing ability can be controlled by absorbing the potential fluctuation due to the deterioration of the photoconductor.

[Sixteenth Embodiment] An image forming apparatus used in the sixteenth embodiment is basically the same as the image forming apparatus used in the fourth embodiment, so that illustration and description are omitted, and different parts will be described. Add. In the sixteenth embodiment, a toner density sensor is incorporated in the developing device so that the toner density (TC) can be detected at any time, so that average data can be captured every 0.2 seconds. As a toner density sensor, T.V. C is used to output a change in magnetic permeability due to a change in voltage as a change in voltage. By comparing the output voltage with respect to T.C. The level of C is determined.

Further, the motor driving the developing device generates a pulse in accordance with the rotation, and the total number of rotations can be detected by the counter, whereby it is possible to know how much the developer has been stirred. .

Further, as shown in FIG. 30B, the discharge duct portion of the developing device at the position of FIG.
A relative humidity sensor (temperature and humidity sensor) is built in,
The relative humidity of the developing device can be determined. In order to detect the environmental condition of the developer atmosphere, it is desirable to directly measure the environment inside the developing device. However, if a sensor is provided inside the sensor, the sensor will become dirty with the toner, making accurate measurement impossible. By measuring the air after passing through the filter of the exhaust pressure duct, the internal environment of the developing device is accurately measured without being contaminated with toner.

FIG. 47 shows the structure of the process control apparatus according to the sixteenth embodiment. In the sixteenth embodiment, the stress detecting unit 63 applied to the developer is classified according to the factors that cause the developing capability to vary.
0, an environmental condition detecting unit 631, and a toner density transition detecting unit 632, each of which is obtained by synthesizing a membership function from the three detecting units, as input information. Estimate developing capacity or developing capacity in the near future. The control destination and control amount determination unit 634 determines a control destination and a control amount based on the estimation result. Further, based on the determined control amount, a charging control unit 635 that performs control, an exposure control unit 636,
A developing bias controller 637 and a toner supply clutch controller 638 are provided. Each power supply controlled by each control unit can be controlled in an analog manner.

FIGS. 48 (a), (b) and (c) show membership functions for determining the effect on the developing ability of each detection unit.

FIG. 48 (a) shows the membership function of the stress detector 630 applied to the developer, and its inference rules are as shown in Tables 1 to 5 below.

[Table 26]

FIG. 48B shows a membership function of the development detecting section 631, and its inference rules are as shown in Tables 27 to 20.

[Table 27]

FIG. 48C shows the toner density transition detecting section 63.
Table 2 shows the membership function, and its inference rules are shown in Table 2.
The rules 11 to 35 shown in FIG.

[Table 28]

Here, as an example, the inference process of the stress detector 630 applied to the developer will be described. For example, the total rotation time of the developing device required for the developer to reach its life is 1
Assuming that the total rotation time is 55% in the case of 00%, the antecedent part is subject to two rules 3 and 4 belonging to MM and MS as shown in FIG. Rules 3 and 4
Accordingly, a shaded portion of the consequent portion corresponding to the developing capacity change amount is inferred. Similarly, a relative humidity of 85 (RH%), a toner density of 1.75 (%), and a change in the developing capacity when the difference from the previous value of the toner density is 0 are also inferred.

Next, as shown in FIG. 49, the total amount of change in the developing ability is expressed by a single membership function by MAX combining the inference results obtained by the respective detection units.
By defuzzifying (obtaining the center of gravity) the hatched portion, a specific change amount is inferred. By calculating the center of gravity, a change in developing ability = -12% is obtained. In the sixteenth embodiment, this value is continuously reduced to −35% or less.
When the inference is made, "toner end" is displayed, the apparatus is stopped, and the apparatus is set in a toner supply standby state.

The obtained change in the developing ability is easily converted to the developing ability (mg / cm ² ) by giving an initial set value of the developing ability (target value at the time of design). Here, the initial set value is 0.7 (mg / cm ² ), and the developing ability is 0.6 based on the above-mentioned inference result (developing ability change amount = −12%).
2 (mg / cm ² ).

Next, the control destination and control amount determination section 634
Will be described. The developing ability obtained so far indicates the amount of adhesion on the photoconductor when the solid black is developed with respect to the initial target developing potential. Therefore, the developing ability and the image density have a close relationship as shown in FIG. 50, and based on the determined developing ability,
By changing the latent image forming condition and the developing bias condition in addition to the toner replenishing condition, the target image density can be always maintained.

Here, the reason why the development potential is changed by changing not only the toner replenishing amount but also the latent image forming condition and the developing bias condition is that the control of only the toner replenishment has a considerable delay in the response time. In such a case, an original having a large image forming area may be continuously copied, or the amount of toner may be reduced, so that an intended replenishment amount may not be obtained. In such a case, the image density can be stably controlled. That's why.

This control is always performed during image formation. However, since the amount of control is extremely fine, and each power supply uses a type that can output analog finely correspondingly, the control is performed during image formation. Thus, ideal control can be performed without a sudden change in image density at

FIG. 51 shows a control destination and a control decision unit 634.
The upper part (development ability inference result) is the antecedent part, the lower part is the consequent part, and the lower part is the consequent part.
Inference is performed according to the rules shown in Table 29 below. In addition,
The determined control amount is reset every time, and the initial state (in the sixteenth embodiment, V _D = −800 V, V _L. = −50 V,
Returning to V _B = -600V), so that the next time is controlled again by the inference result.

[0195]

[Table 29]

For example, when the developing capacity is 0.7 (mg / cm
² ), it is apparent from FIG. 51 that the antecedent part has eight rules (rules 45 to 45) belonging to MS and MM.
52). According to this rule, the hatched portion (see FIG. 51) of the consequent corresponding to each control destination is inferred. The control amount is determined for each of these by determining the center of gravity.
Here, grid control amount: +65 V, exposure control amount: +
65 V, a developing bias control amount: +65 V, and a toner replenishment control amount: + 20%. The control amount thus obtained is converted into an actual control value corresponding to an inference result based on the initial control value initially set in each control unit, and control is performed.

In the conventional control method, the table reference type control is mainly performed, and since the step width of the control value is large, if the developing bias or the like is changed during image formation, the image density temporarily changes suddenly. Although it is difficult to adjust the image density during image formation, according to the sixteenth embodiment, it is possible to always perform ideal control by fine-grained control even during image formation, thereby improving the stability of image density.

[0198]

As described above, the image forming method of the present invention can comprehensively judge multi-dimensional information and can cope with any conceivable temporal environment.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first embodiment according to the present invention.

FIG. 2 is an explanatory diagram showing a membership function used in the first embodiment.

FIG. 3 is an explanatory diagram illustrating an operation of the image forming method according to the first embodiment;

FIG. 4 is an explanatory diagram showing a configuration of a second embodiment according to the present invention.

FIG. 5A is an explanatory diagram showing a membership function used in the second embodiment, and FIG. 5B is an explanatory diagram showing a composite output.

FIG. 6 is an explanatory diagram showing a configuration of a third embodiment according to the present invention.

FIG. 7 is an explanatory diagram showing a membership function used in the third embodiment.

FIG. 8 is an explanatory diagram illustrating a configuration of an image forming apparatus.

FIG. 9 is an explanatory diagram illustrating a control flow according to the fourth embodiment;

FIG. 10 is an explanatory diagram showing a membership function used in the fourth embodiment.

FIG. 11 is an explanatory diagram of a specific example of fuzzy inference according to the fourth embodiment;

FIG. 12 is an explanatory diagram illustrating a control flow according to the fifth embodiment;

FIG. 13 is an explanatory diagram showing a membership function used in the fifth embodiment.

FIG. 14 is an explanatory diagram illustrating an example of a user input unit.

FIG. 15 is an explanatory diagram illustrating a control flow according to the sixth embodiment;

FIG. 16 is an explanatory diagram showing a membership function used in the sixth embodiment.

FIG. 17 is an explanatory diagram showing a relationship between a toner supply amount, a toner remaining amount, and an agitator torque.

FIG. 18 is an explanatory diagram showing a control flow according to the seventh embodiment.

FIG. 19 is an explanatory diagram showing a membership function used in the seventh embodiment.

FIG. 20 is an explanatory diagram showing a control flow according to the eighth embodiment.

FIG. 21 is an explanatory diagram showing a membership function used in the eighth embodiment.

FIG. 22 is an explanatory diagram comparing an effect obtained when the fifth to eighth embodiments are combined with an effect obtained by controlling only detection by a conventional optical sensor.

FIG. 23 is an explanatory diagram illustrating a control flow according to the ninth embodiment;

FIG. 24 is an explanatory diagram showing a membership function used in the ninth embodiment.

FIG. 25 is an explanatory diagram of a specific example of fuzzy inference according to the ninth embodiment;

FIG. 26 is an explanatory diagram showing a control flow according to the tenth embodiment.

FIG. 27 is an explanatory diagram showing a membership function used in the tenth embodiment.

FIG. 28 is an explanatory diagram showing a control flow according to the eleventh embodiment.

FIG. 29 is an explanatory diagram showing a membership function used in the eleventh embodiment.

FIG. 30 is an explanatory diagram illustrating a configuration of an image forming apparatus according to a twelfth embodiment;

FIG. 31 is an explanatory diagram illustrating a configuration of a process control device according to a twelfth embodiment;

FIG. 32 is an explanatory diagram showing membership functions used in each detection unit.

FIG. 33 is an explanatory diagram of a specific example of fuzzy inference according to the twelfth embodiment;

FIG. 34 is an explanatory diagram showing a relationship between image density and developing ability.

FIG. 35 is an explanatory diagram showing a membership function used in a control destination and a control amount determination unit.

FIG. 36 is an explanatory diagram showing a relationship between V _SP / V _SG and developing ability.

FIG. 37 is an explanatory diagram illustrating a configuration of a process control device according to a thirteenth embodiment;

FIG. 38 is an explanatory diagram showing a membership function of a developing ability detection unit.

FIG. 39 is a comparison diagram of the effects between the conventional method and the thirteenth embodiment.

FIG. 40 is an explanatory diagram illustrating the configuration of the process control device according to the fourteenth embodiment;

FIG. 41 is an explanatory diagram showing membership functions used in each detection unit.

FIG. 42 is an explanatory diagram of a specific example of fuzzy inference according to the fourteenth embodiment;

FIG. 43 is an explanatory diagram showing a relationship between image density and developing ability.

FIG. 44 is an explanatory diagram illustrating a membership function used in a control destination and a control amount determination unit.

FIG. 45 is an explanatory diagram illustrating a configuration of a process control device according to a fifteenth embodiment;

FIG. 46 is an explanatory diagram showing a membership function of a developing ability detection unit.

FIG. 47 is an explanatory diagram showing the configuration of the process control device according to the sixteenth embodiment.

FIG. 48 is an explanatory diagram showing a membership function used in each detection unit.

FIG. 49 is an explanatory diagram of a specific example of fuzzy inference according to the sixteenth embodiment;

FIG. 50 is an explanatory diagram showing a relationship between image density and developing ability.

FIG. 51 is an explanatory diagram showing a membership function used in a control destination and a control amount determination unit.

FIG. 52 is an explanatory diagram showing a copying apparatus to which a conventional image forming method is applied.

FIG. 53 is an explanatory diagram illustrating a control operation of a conventional image forming method.

FIG. 54 is an explanatory diagram showing a control operation of a conventional image forming method.

FIG. 55 is an explanatory diagram showing a control operation of a conventional image forming method.

[Explanation of symbols]

101 P sensor (photo sensor) 102 A
/ D converter 103 MPU 104 Latch 105 Subtractor 106 Fuzzy controller 107 Solenoid driver 108 Clutch solenoid 109 Error counter 110 Adder / subtractor 111 Limiter 112 Latch 113-116 Latch 117 Averaging circuit 118 Subtractor 501 Latch 502 Fuzzy controller 503 Unit image forming signal Toner supply amount storage / readout unit 504 Integration counter 505 Toner supply clutch 511 C memory readout unit 512 515 Latch 513 51
6 Difference calculation 514 Fuzzy controller 517 Storage / readout unit of toner supply amount per unit image formation signal 518 Integration counter 519 Toner supply clutch 520 Fuzzy controller 521 Latch 522 Difference calculation 523 Fuzzy controller 524 Storage / readout unit of toner supply amount per unit time 525 Integration counter 526 Toner supply clutch 530 Fuzzy controller 540 Total supply signal integration counter 541 Toner supply clutch 542 Fuzzy controller 550 Latch 551 A
/ B calculation unit 552 553 Accumulation counter 554 Fuzzy controller 555 Toner supply / storage unit per unit image forming signal storage / readout unit 556 Control signal generation unit 557 Toner supply clutch 560 C memory readout unit 561 Latch 562 A
/ B calculation unit 563 integration counter 564 integration counter 565 integration counter 566 latch 567 D / E calculation unit 568 fuzzy controller 569 fuzzy controller 570 toner supply amount storage / readout unit per unit image forming signal 571 control signal generation unit 572 toner supply clutch 580 Fuzzy controller 581 C memory readout unit 582 Fuzzy controller 583 Latch 584 585 Integration counter 586 A
/ B calculation unit 587 Toner supply amount storage / readout unit per unit image formation signal 588 Control signal generation unit 589 Toner supply clutch 590 600 630 Stress detection unit 591 601 631 Environmental condition detection unit 592 602 632 Toner density transition detection unit 593 604 612 624 633 Developing capacity estimating unit 594 605 614 625 634 Control destination and control amount deciding unit 595 606 615 626 635 635 Charging control unit 596 607 616 627 636 Exposure control unit 597 608 617 628 637 Developing bias control unit 698 698 Supply clutch controller 603 623 Developing capacity detector 610 620 Long-term factor detector 611 621 Medium-term factor detector 612 622 Short-term factor detector

Continued on the front page (72) Inventor Mitsuhisa Kanaya 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Koichi Noguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Inventor Toshihiko Kuroi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-3-10272 (JP, A) JP-A-2-311860 (JP) JP-A-62-34179 (JP, A) JP-A-1-139905 (JP, A) JP-A-3-10269 (JP, A) JP-A-3-119377 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/00 G03G 15/08 G03G 21/00

Claims (2)

(57) [Claims] 1. An image forming method using an electrophotographic method, comprising: a total rotation time of a developing device, a relative humidity in the developing device, a toner density, and respective membership functions for a difference between a toner density and a previous measured value. Inferring the amount of change in the developing capacity based on the relative humidity in the developing device used for the membership function, the toner density, and the respective control rules relating to the difference between the toner density and the previous measured value. Converting the inference result of the capacity change amount to the development capacity; and a membership function for the grid control amount, the exposure control amount, the development bias control amount, and the toner replenishment control amount corresponding to the obtained development capability, and The grid control amount, exposure control amount, developing bias control amount, and toner compensation amount used for the membership function Inferring and determining a grid control amount, an exposure control amount, a developing bias control amount, and a toner replenishment control amount based on the respective control rules related to the supply control amount. . 2. The scale of the membership function:
2. The image forming method according to claim 1, wherein the change is performed based on a detection result of the detection pattern by the optical sensor.