JPH11143307A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the occurrence of a state where printing processing efficiency is decreased or a printing start is impossible and to form an image of high quality by executing a cleaning operation in an image forming device, in accordance with the degree of the actual soiling in the image forming device. SOLUTION: Information on toner consumption is detected (#4) and the execution intervals of the cleaning operation in the device are controlled based on the information. Thus, the cleaning operation in the device can be executed according to the degree of the actual soiling in the device, so that in the case where it is assumed that the inside of the device is not soiled because the toner consumption is low, even if the number of prints is large (NO in the #7), the inside of the device is not cleaned. Further, in the case where it is assumed that the inside of the device is soiled because the toner consumption is high, even if the number of the prints is small (YES in the #7), the inside of the device is cleaned (#8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus which forms an image by transferring a toner image formed by an electrophotographic method onto a recording medium.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus which forms an image by transferring a toner image formed by an electrophotographic method onto a recording medium, the inside of the apparatus becomes dirty due to scattering of toner while copying is continued. In some cases, dirt and noise may occur in an image. For example, in a color copying machine of a type in which four color toner images are superimposed using a transfer drum, dirt on the transfer drum causes dirt on the back surface of the copy. In addition, fog or white spots on a copy may occur due to contamination of the charged charge wire. In a conventional image forming apparatus, in order to prevent such a problem from occurring, control is performed such that the inside of the apparatus is cleaned every time printing of a predetermined number of sheets is completed, thereby preventing contamination inside the apparatus. In.

[0003]

However, in the above-described conventional image forming apparatus, when performing a cleaning operation in the apparatus during continuous printing, the printing operation must be interrupted to perform the cleaning operation. Therefore, the efficiency of the printing process is reduced, and when the cleaning operation inside the apparatus is performed after the printing operation is completed, the next printing cannot be started until the cleaning process is completed. In a conventional image forming apparatus, when the number of printed sheets reaches a predetermined number of printed sheets, it is determined that dirt in the apparatus has reached a level necessary for the cleaning operation, and the inside of the apparatus is cleaned. However, actual stains in the apparatus vary depending not only on the number of printed sheets up to now, but also on the use mode, toner consumption, and the like. Among them, the influence of the toner consumption is great. In a conventional image forming apparatus, in order to cope with a case where the amount of toner consumption is large, a predetermined number of printed sheets, which is a criterion for performing a cleaning operation, is set small in anticipation of safety, and the interval between cleaning operations in the apparatus is shortened. I was For this reason, even if the amount of toner consumption is small and the inside of the apparatus is not so dirty, the cleaning operation in the apparatus may be performed. Was invited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made in consideration of the actual degree of contamination in an apparatus so that a cleaning operation in the apparatus can be performed. It is an object of the present invention to provide an image forming apparatus capable of forming a high-quality image while minimizing a reduction in efficiency and occurrence of a state where printing cannot be started.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an image forming apparatus for forming an image by transferring a toner image formed by an electrophotographic method onto a recording medium. A toner consumption information detecting means for detecting information; and a control means for controlling an execution condition of a cleaning operation in the apparatus based on the toner consumption information detected by the toner consumption information detecting means. .

In the above arrangement, information relating to the amount of toner consumption is detected, and the conditions for performing the cleaning operation in the apparatus are controlled based on the toner consumption information. Specifically, the length of the execution interval of the in-apparatus cleaning operation is mainly controlled. As a result, the cleaning operation in the apparatus can be performed in accordance with the degree of contamination in the actual apparatus. Therefore, even if the number of printed sheets is large, the toner consumption is small and the inside of the apparatus is small. If it is not dirty, it is possible to prevent the inside of the apparatus from being cleaned.Also, even if the number of printed sheets is small, if the amount of toner consumption is large and the inside of the apparatus is dirty, The inside of the device can be cleaned. Accordingly, it is possible to minimize the reduction in the printing processing efficiency and the occurrence of a state where printing cannot be started due to the execution of the cleaning operation in the apparatus, and to perform the cleaning operation in the apparatus at an appropriate timing to perform high-quality image processing. Can be formed. When determining whether or not to perform the cleaning operation in the apparatus, the color mode of the full-color copy or the mono-color copy, the freshness of the developer, the freshness of the photoconductor, or the pause time since the previous use of the copy is determined. In this case, more optimal control can be performed. Information on the toner consumption can be obtained from the density information of the document.

Further, the toner consumption information detecting means can use a dot counter for counting the number of dots according to the density of the original image. By using the dot counter for detecting the toner consumption information, the toner consumption information can be accurately predicted. The dot counter is also used for controlling the toner supply amount.

Further, the control means controls the execution condition of the cleaning operation in the apparatus based on the toner consumption information detected by the toner consumption information detecting means and the number of printed sheets after the previous cleaning operation in the apparatus. be able to. Specifically, based on the toner consumption information and the number of printed sheets after the previous internal cleaning operation, the control unit mainly controls the execution interval and the length of the internal cleaning operation. Thus, the toner consumption information and the number of printed sheets after the previous cleaning operation in the apparatus can be taken into consideration, so that the degree of contamination in the apparatus is determined based on only the toner consumption information. It becomes possible to more accurately determine the degree of contamination in the apparatus and control the conditions for performing the cleaning operation in the apparatus based on the result of the determination.

The control means can control the conditions for performing the transfer drum cleaning operation. As a result, the transfer drum cleaning operation can be performed according to the degree of contamination in the actual apparatus. Generation can be minimized, and a high-quality image can be formed by performing the transfer drum cleaning operation at an appropriate timing.

[0010] Further, the control means can control the execution condition of the charged wire cleaning operation. This makes it possible to carry out the charged charge wire cleaning operation according to the degree of contamination in the actual device,
A reduction in print processing efficiency and the occurrence of a state in which printing cannot be started due to the execution of the charged charge wire cleaning operation can be minimized, and a high quality image is formed by performing the charged charge wire cleaning operation at an appropriate timing. can do.

The control means describes the toner consumption information and the transfer drum rotation speed by a membership function, the antecedent part of the inference rule is described by the toner consumption information and the transfer drum rotation speed, and the consequent part describes the inference rule. Using a fuzzy inference type rule described with an estimated value of contamination in the apparatus, the toner consumption information detected by the toner consumption information detecting means and the transfer drum rotation number after the previous cleaning operation in the apparatus are used as input values. By giving it to the subject part, an estimated value of the consequent part is determined by fuzzy inference including the min-max centroid method, and based on the estimated value, the condition for performing the cleaning operation in the apparatus can be controlled.

In the above arrangement, the toner consumption information detected by the toner consumption information detecting means and the transfer drum rotation speed after the previous cleaning operation in the apparatus are given as input values to the antecedent portion, so that min-max is obtained. An estimated value of the consequent part is determined by fuzzy inference including the center of gravity method, and based on the estimated value, the execution condition of the cleaning operation in the apparatus is controlled. This makes it possible to perform the cleaning operation in the apparatus based on the accurate estimated value of the contamination in the apparatus obtained by considering both the toner consumption amount information and the rotation speed of the transfer drum after the previous cleaning operation in the apparatus. Can be accurately controlled.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing the entire configuration of the digital full-color copying machine according to the present embodiment. A digital full-color copying machine 1 (hereinafter abbreviated as a copying machine) includes an image reader unit 2 for reading image data of a document, and a printer unit 3 for printing an image on paper. In the image reader section 2, the scanner 4 is moved by the scanner motor 5 in the direction of the arrow (sub-scanning direction) to scan the entire document placed on the document table 6. At this time, the document on the document table 6 is irradiated by an exposure lamp 7 provided in the scanner 4, and reflected light from the document surface is reflected by mirrors 8 to 11 and a condenser lens 12.
An image is formed on the full-color CCD sensor 13 via a (not shown). The full-color CCD sensor 13 converts the reflected light from the original into red (R), green (G), and blue (B) electric signals (analog signals) and outputs the electric signals to the image signal processing unit 14.
The image signal processing unit 14 converts the input analog image signal into a digital image signal and performs various types of image processing, and then converts the image signal into cyan (C), magenta (M), yellow (Y), and black ( K) creates a digital image signal (laser drive signal) color-converted to the laser device 2
Output to 1. The laser device 21 emits a laser beam based on the input digital signal.

Next, in the printer section 3, the laser beam emitted from the laser device 21 exposes the photosensitive drum 23 charged by the charging charger 22,
An electrostatic latent image is formed. Then, toner developing units 24 to 27 of four colors of cyan, magenta, yellow, and black are sequentially selected, and develop the electrostatic latent images of the respective colors on the photosensitive drum 23 in this order. Next, an appropriate cut sheet is conveyed from the sheet cassettes 30 to 32 and is attracted to the transfer drum 36 by an electrostatic attraction charger 35 provided to face the attraction roller 34 via the timing roller 33. The toner images of each color developed on the photoconductor drum 23 are transferred by the transfer charger 37 onto the paper wound around the transfer drum 36. The rotation of the transfer drum 36 is controlled by a drum motor 38 (not shown). The above transfer step is repeatedly performed for four colors of cyan, magenta, yellow and black. That is, the transfer drum 36 rotates four times. Thereafter, the paper is subjected to static elimination on the surface of the transfer drum 36 by the separation charger 39 and the static elimination charger 40, and
The toner is separated from the transfer drum 36 by the action of the separation claw 41 and is conveyed to the fixing device 42. This fixing device 42
It is composed of an upper roller 44 and a lower roller 45, and each roller is adjusted to a predetermined temperature by a heater. The toner image transferred onto the sheet is heated and pressed by upper and lower rollers 44 and 45 and fixed on the sheet. Then, the sheet that has passed through the fixing device 42 is
It is discharged to 3. At the time of double-sided copying, the discharged sheet is reversed by the sheet reversing unit 46, and the transfer process is performed again on the transfer drum 36.

The printer unit 3 is connected to the image signal processing unit 14 of the image reader unit 2 via a counter image memory (not shown) by another image data bus. The counter memory counts and stores, for each level, 256-bit 8-bit data representing the image density level of each dot of the original image from the image signal processing unit 14. The counter memory stores data for each scan of the scanner 4, and the printer unit 3 reads data for one scan in accordance with a scanner operation signal sent from the image reader unit 2. The counter memory discards the data when the printer unit 3 finishes reading data for one scan.

Next, a description will be given, with reference to FIG. 2, of a calculation for estimating the amount of toner consumed by the printer unit 3 of the copying machine 1. FIG. 2 is a histogram showing the number of dots for each image density level of the document image acquired by the printer unit 3 from the counter memory. Counter memory is full color CC
Cyan, magenta, yellow, and the like obtained by color-converting the red, green, and blue signals from the D sensor 13.
Each light image of each black color has a histogram as shown. Since the amount of toner consumed per dot for each image density level can be estimated, the amount of toner consumed per dot is multiplied by the amount of toner consumed per dot shown in FIG. By calculating and integrating the toner consumption amounts of all levels, it is possible to calculate the estimated toner consumption amount for one scan.

Here, the amount of toner consumed per dot for each image density level is obtained as follows.
It is stored in the OM. FIG. 3 is a diagram showing the relationship between the document image density and the image density level, FIG. 4 is a diagram showing the relationship between the document image density and the toner adhesion amount on the photoconductor, and FIG. 5 is the relationship between the image density level and the toner adhesion amount on the photoconductor. FIG. Originally, the tone reproduction of the printer section is to widen the color reproduction range,
As shown in FIG. 3, the image density of the document (ID: Image
(Density), the density level of the reproduced image is increased or decreased. Copier 1 according to the present embodiment
The relationship between the toner adhesion amount on the photoreceptor and the image density of the original is as shown in FIG. 4, and the relationship between the toner adhesion amount on the photoreceptor and the reproduced image density level is as shown in FIG. From the relationship between the toner adhesion amount on the photoreceptor and the image density level, the amount of toner consumed per dot for each image density level is obtained and stored in a data ROM as a lookup table as shown in Table 1 below. I have.

[0018]

[Table 1]

According to the above-described method, the toner consumption of each color can be calculated at the time of each scan of cyan, magenta, yellow, and black, and the toner consumption per copy can be calculated by adding them up.

Next, control of the transfer drum cleaning operation of the copying machine 1 according to the present embodiment will be described with reference to FIG. FIG. 6 is a diagram showing an operation sequence of cleaning the transfer drum of the copying machine 1 according to the present embodiment. The transfer drum cleaning is performed for the purpose of removing the toner and the residual current attached to the transfer film by repeating the copying operation. If this cleaning is not performed, toner contamination occurs on the surface of the paper that is attracted to the transfer film, that is, on the back surface. Usually, the transfer drum cleaning is performed before the transfer drum 36 stops after the image pickup operation is completed and the sheet is separated from the transfer drum 36. As shown in FIG. 6, first, the transfer film stretched on the drum surface of the transfer drum 36 is recharged by the suction charger 35, the suction roller 34, and the suction backup film, so that the toner on the transfer film is recharged. Let it. Next, the fur brush unit is operated to collect the toner on the transfer film. Then, the charge remaining on the inside and outside of the transfer film is removed by the charge removal charger 40 to initialize the transfer film.

The above-described cleaning of the transfer drum is performed after the completion of all the imaging operations or during the multi-copy (continuous copy) by interrupting the copy operation. Conventionally, transfer drum cleaning during multi-copy has been performed when a predetermined number of multi-copy has been performed. The predetermined number is determined by estimating the degree of dirt on the transfer drum 36 from experiments, etc., but if the dirt on the transfer drum 36 becomes severe, it may cause show-through of the copy, so set a small number in anticipation of safety. Have been. In such a case, even if the transfer drum 36 is cleaned after reaching the predetermined number, the transfer drum 36 may not actually be so dirty. In the embodiment of the present invention, the cleaning of the transfer drum is determined in consideration of the toner consumption by the dot counter in addition to the number of copies. When the amount of consumed toner is large, the amount of toner transferred from the developing units 24 to 27 to the photosensitive drum 23 increases, so that the amount of toner smoke increases and the amount of toner adhered to the transfer drum film increases.

FIG. 7 is a flowchart showing a process of cleaning the transfer drum of the copying machine 1 according to the present embodiment. First,
The copy mode such as the number of copies and the color mode is set by the user (# 1), and when the print key is turned on (YES in # 2), the number of multi-copy is added (#
3) The printing operation is performed, and the integrated value of the estimated toner consumption is calculated (# 4). In this calculation, the number of dots for each image density level of the original image is counted by a dot counter, and information on the number of dots for each image density level and the amount of toner adhering to the photoconductor for each image density level stored in the data ROM are stored. The information can be obtained by reading out the above information and calculating the expected toner consumption required in the image forming process for one sheet based on the information. Next, it is determined whether the set number of copies has been completed (# 5). If the set number of copies has not been completed (# 5: N
O), the amount of dirt in the machine is estimated (# 6), and if the amount of dirt in the machine is smaller than a predetermined value (N in # 7)
O), returning to the process of # 3. If the amount of dirt in the apparatus is larger than the predetermined value (YES in # 7), the transfer drum 3
After the cleaning of No. 6 is performed (# 8), the predicted consumption integrated value and the number of multi-copy sheets are returned to 0 (# 9), and the process returns to # 3. If it is determined in step # 5 that the set number of copies have been completed (YES in # 5), the transfer drum 36
Is cleaned (# 10), the predicted consumption integrated value and the number of multi-copy sheets are returned to 0 (# 11), and the process ends.

The copying machine 1 according to the present embodiment has a
In estimating the amount of dirt in the apparatus necessary for determining whether to perform the transfer drum cleaning, fuzzy inference using the above-mentioned multi-copy number and the estimated consumption integrated value is used. As a result, if the toner consumption is large, the transfer drum 36 is cleaned with a smaller number of multi-copy sheets than usual, and if the toner consumption is small, the transfer drum 36 is cleaned with a larger multi-copy number than usual. Further, even when the B / W ratio representing the density of the document changes in multi-copy using the ADF, the estimated toner consumption is integrated, so that the transfer drum 36 is cleaned at an appropriate timing. .

Next, the contents of the fuzzy inference performed in the process of # 6 in FIG. 7 will be described. In this fuzzy inference, the in-machine contamination amount is determined from the above-described multi-copy number and the estimated consumption amount integrated value according to the following rules. The state quantity as input and the estimated quantity as output of fuzzy inference are as follows. Here, the predicted consumption integrated value is obtained by estimating and adding the toner consumption for each copy, and is cleared when the transfer drum 36 is cleaned. The multi-copy number is the number of copies after the previous transfer drum cleaning. The amount of dirt in the apparatus indicates the degree of dirt on the transfer drum 36 obtained from an experiment or the like, and the limit dirt at which the transfer drum 36 should be cleaned is 100%. In the embodiment of the present invention, the transfer drum 36 is cleaned when the in-machine contamination amount exceeds 80%.

Next, the membership function of the fuzzy set of the state quantity and the estimated quantity will be described with reference to FIGS. FIGS. 8A to 8C are fuzzy set membership functions of the predicted consumption integrated value, the number of multi-copy sheets, and the in-machine contamination amount, respectively, and FIGS. 9A and 9B are FIGS. 8A and 8B, respectively. It is a figure which shows the example of determination of the certainty factor of the state quantity using the membership function of b). Here, the symbols shown in FIGS. 8 and 9 represent the meanings of NL: very small NS: slightly small ZO: standard PS: slightly large PL: very large Each piece of information is defined based on experience from experiments and the like. The vertical axis of the graph represents the degree of certainty of the fuzzy set of each symbol, and takes an arbitrary value in the range of 0 to 1. For example, as shown in FIG. 9A, when the predicted consumption integrated value is 2200 mg, ZO and PS are selected as the state quantities, and the confidence of ZO is 0.8.
Thus, the confidence factor of the PS becomes 0.2. Further, as shown in FIG. 9B, when the number of multi-copy sheets is 28,
NS and ZO are selected as the state quantities, and the confidence of NS is 0.4 and the confidence of ZO is 0.6. in this way,
The certainty factor of each state quantity can be obtained for a certain input value from the membership function.

Next, with reference to FIG. 10, the inference rules in the fuzzy inference performed in the in-machine contamination amount estimation processing of # 6 in FIG. 7 will be described. FIG. 10 is a diagram showing an inference rule used for estimating the amount of dirt in the copying machine 1. As shown in the figure, this inference rule is expressed in a matrix with respect to the estimated consumption amount integrated value and the number of multi-copy sheets. In other words, this inference rule is a fuzzy inference type rule in which the antecedent part is described by the estimated consumption amount integrated value and the number of multi-copy sheets, and the consequent part is described by the estimated value of the in-machine contamination amount. The number of inference rules is 25, and in accordance with these rules, the estimated amount of the in-machine stain amount with respect to the predicted consumption integrated value as the input state amount and the number of multi-copy sheets is determined. For example, as shown in FIG. 9, when ZO and PS are selected as the input state quantities for the predicted consumption integrated value and NS and ZO are selected as the input state quantities for the number of multi-copy sheets, The inference rules used are:

[0027]

[Table 2] Predicted consumption integrated value Multi-copy number In-machine dirt amount rule if ZO and NS then ZO rule if ZO and NS then ZO rule if PS and NS then ZO rule if PS and NS then ZO rule if PS and ZO then PS rule.

Based on the above inference rules and each of the membership functions shown in FIG. 8, the estimated amount of in-machine dirt is calculated by the min-max centroid method. FIG.
As shown in (a), the confidence of the predicted consumption integrated value ZO, which is the state quantity, is 0.8, the confidence of the predicted consumption integrated value PS is 0.2, and FIG. As shown in the figure, the confidence of the multi-copy number NS, which is the state quantity, is 0.
4. The certainty factor of the multi-copy number ZO is 0.6. The estimated amount of the in-machine contamination amount is determined based on the rule ~, and the certainty of the estimated amount is selected from the smaller one of the estimated consumption integrated value and the certainty of the input state amount regarding the number of multi-copy sheets. . According to this method, the certainty factor of the amount of in-machine contamination as asserted by Rule 1 is determined as follows.

[0029] Therefore, the rule asserts that the confidence of the in-machine dirt amount ZO is 0.4.

Rule: Confidence of predicted consumption integrated value ZO = 0.8 Confidence of multi-copy number ZO = 0.6 Therefore, the rule asserts that confidence of in-machine dirt amount ZO = 0.6.

[0031] Therefore, the rule asserts that the certainty of the in-machine dirt amount ZO is 0.2.

[0032] Therefore, the rule asserts that the certainty of the in-flight dirt amount PS is 0.2.

FIG. 11 is a diagram showing the synthesis of certainty factors of the estimated amount of in-machine contamination. The hatched portions shown in the figure show the overlapping portions of the estimated amounts of the membership functions of the fuzzy set of the in-machine dirt amount, which are truncated based on the assertion result of the rule ~. Since the estimated amount of in-machine dirt determined by the rule (1) is only ZO and PS,
Only the fuzzy set of PS and PS has a shaded portion. The center of gravity of the hatched portion is the output estimation amount. In this case, the in-machine dirt amount, which is the estimated output amount, is 58%.

In the present embodiment, the estimated amount of in-machine dirt in the consequent part is defined as a fuzzy set, and min-ma
Although the output estimation amount of the consequent part is calculated using the x centroid method, the estimation amount of the in-machine contamination amount of the consequent part is defined as a constant,
The output estimation amount of the consequent part may be calculated by the load average using the simplified inference method, or the estimation amount of the in-machine contamination amount of the consequent part may be defined as a function, and the functional inference method may be used. May be used to calculate the output estimation amount of the in-machine contamination amount. Further, the shape of the membership function of the predicted consumption integrated value, the number of multi-copy sheets and the amount of contamination in the machine, and the number and contents of the inference rules can be changed according to experience and experimental results.

Next, the control of the charging / charging wire cleaning operation of the copying machine 1 according to the present embodiment will be described. The cleaning of the charged charge wire is performed in order to prevent the charged charge wire from being stained due to adhesion of a toner plume or the like due to repeated copying, and to prevent the image from being fogged due to a reduction in the charging ability of the charged charge wire. The cleaning of the charging wire must be performed when the output of the charging charger 22 is turned off and all the driving of the photosensitive drum 23 and the like are stopped. Conventionally, the number of copies after the previous cleaning of the charged wire is counted, and when the number of copies is equal to or more than a predetermined number at the end of the copy operation, the cleaning operation is automatically performed. , The next copy cannot be started during the cleaning operation. For this reason, even though the user wants to start the next copy, the copy cannot be started because the cleaning operation is being performed, and the usability may be deteriorated. The predetermined number of copies used to determine whether or not to perform the charging charge wire cleaning is set based on experiments and the like, in anticipation of the degree of contamination of the charging charge wire. Because fogging occurs in the copy, we set it a little lower in anticipation of safety. For this reason, even if the number of copies reaches a predetermined number and the charged charge wire is cleaned, the wire may not actually be so dirty. In the copying machine 1 according to the present embodiment, in addition to the number of copies,
The execution of the charge wire cleaning control is determined in consideration of the toner consumption obtained by the dot counter. When the amount of consumed toner is large, the amount of toner transferred from the developing devices 24 to 27 to the photosensitive drum 23 increases, so that the amount of toner smoke increases and the amount of toner adhered to the charge wire increases.

Next, with reference to FIG. 12, a mechanism for cleaning the charged charge wire will be described. FIG. 12 is a transparent perspective view of the charging charger 22. Charger 22
A cleaning motor 51 is provided on the right side in the drawing, and the cleaner 52 moves by the rotation of the cleaning motor 51 to clean the charged charge wire 53. A charge cleaner return position sensor 54 and a charge cleaner fixed position sensor 55 provided on both left and right sides of the charging charger 22 detect a forward rotation / reverse rotation switching position and a stop position of the cleaning motor 51. Based on this detection,
The movement and stop of the cleaner 52 are controlled.

FIG. 13 is a flowchart showing the process of cleaning the charged wire of the copying machine 1 according to the present embodiment. First, the copy mode such as the number of copies and the color mode is set by the user (# 21). When the print key is turned on (YES in # 22), the number of multi-copy is added (# 23), and the printing operation is performed. As well as
An integrated value of the predicted toner consumption is calculated (# 24). In this calculation, the number of dots for each image density level of the original image is counted by a dot counter, and information on the number of dots for each image density level and the amount of toner adhering to the photoconductor for each image density level stored in the data ROM are stored. Read the information of
Based on such information, it can be obtained by calculating the expected toner consumption amount required in one image forming process. Next, it is determined whether or not the set number of copies has been completed (# 25). If the set number of copies has not been completed (NO in # 25), the processes of # 23 to # 25 are repeated. If the set number of copies has been completed (YES in # 25), the amount of dirt in the apparatus is estimated (# 26). If the amount of dirt in the machine is larger than a predetermined value (Y in # 27)
ES), and clean the charged charge wire 53 (# 2)
8) After resetting the predicted consumption integrated value and the number of multi-copy sheets to 0 (# 29), the process is terminated. When the in-machine contamination amount is smaller than a predetermined value (# 27)
NO), without carrying out cleaning of the charged charge wire 53, the estimated consumption integrated value and the number of multi-copy sheets are carried over to the next copy, and this processing is ended.

The copying machine 1 according to the present embodiment has a
Fuzzy inference using the number of multi-copy sheets and the predicted consumption integrated value as input values is used to determine the amount of in-machine dirt required to determine whether to perform charging charge wire cleaning in the in-machine dirt amount estimating process. The fuzzy inference method is the same as the fuzzy inference method used in the above-described transfer drum cleaning. As a result, if the toner consumption is large, the charging charge wire 53 is cleaned with a smaller number of multi-copy sheets than usual, and if the toner consumption is small, the charging charge wire 53 is cleaned with a larger multi-copy number than usual.
Even in the case where the B / W ratio indicating the density of a document changes in multi-copy using the ADF, the in-machine contamination amount is inferred using the estimated toner consumption amount, so that the charging charge can be performed at a proper timing. The wire 53 is cleaned.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the length of the execution interval of the in-machine cleaning operation is controlled in accordance with the estimated amount of in-machine contamination, but the length of the execution time of the in-machine cleaning operation is controlled in accordance with the estimated amount of in-machine contamination. It may be. In the above-described embodiment, the number of copies after the previous in-machine cleaning operation is used as an input of the fuzzy inference other than the estimated toner consumption value. A color mode such as monochromatic copying, a newness of the developer, a newness of the photosensitive drum 23, or a pause time from the last use of copying may be used as an input of fuzzy inference. In the above-described embodiment, the present invention is applied to an electrophotographic digital full-color copying machine using four color toners of cyan, magenta, yellow, and black. The present invention may be applied to

[0040]

As described above, according to the present invention, since the conditions for performing the cleaning operation in the apparatus are controlled based on the toner consumption information, the cleaning operation in the apparatus is performed according to the actual degree of contamination in the apparatus. Can be implemented. This allows you to perform cleaning operations inside the device only when
Since the cleaning operation inside the device can be performed, the reduction of the print processing efficiency due to the cleaning operation performed during continuous printing and the occurrence of a state where printing cannot be started due to the cleaning operation performed after the completion of the printing operation are minimized. In addition, by performing the cleaning operation in the apparatus at an appropriate timing, generation of noise such as stains on the back of a sheet can be prevented, and a high-quality image can be formed. If a dot counter that counts the number of dots according to the density of the document image is used for detecting the toner consumption information, the toner consumption can be accurately detected.

Further, according to the present invention, the control means sets the execution conditions such as the execution interval and the execution time of the internal cleaning operation based on the toner consumption information and the number of printed sheets after the previous internal cleaning operation. Since the control is performed, the degree of contamination in the apparatus can be more accurately determined as compared with the case where the execution condition of the apparatus cleaning operation is controlled based only on the toner consumption information. This makes it possible to more accurately control the execution condition of the internal cleaning operation.

Further, according to the present invention, the control means controls the execution condition of the transfer drum cleaning operation on the basis of the toner consumption information and the like, so that the transfer is performed in accordance with the actual degree of contamination in the apparatus. The drum cleaning operation can be performed. As a result, it is possible to minimize the reduction in the printing processing efficiency and the occurrence of a state in which printing cannot be started due to the execution of the transfer drum cleaning operation, and to perform the transfer drum cleaning operation at an appropriate timing to prevent the transfer drum from becoming dirty. Can prevent the back surface of the paper from being stained.

Further, according to the present invention, the control means controls the execution condition of the charging and charging wire cleaning operation based on the toner consumption information and the like, so that the control means controls the actual degree of contamination in the apparatus. The operation of cleaning the charged charge wire can be performed. As a result, it is possible to minimize a reduction in print processing efficiency and the occurrence of a state in which printing cannot be started due to the execution of the charging charge wire cleaning operation, and to perform the charging charge wire cleaning operation at an appropriate timing to perform charging charging. It is possible to prevent the occurrence of fogging, white spots, and the like due to wire contamination.

Further, according to the present invention, the control means sets the toner consumption information detected by the toner consumption information detection means and the transfer drum rotation speed after the previous cleaning operation in the apparatus as input values to the antecedent portion. By performing the cleaning operation in the apparatus based on the accurate estimated value of the contamination in the apparatus obtained by taking into account both the toner consumption information and the number of rotations of the transfer drum after the previous cleaning operation in the apparatus. Conditions can be controlled accurately.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an entire configuration of a digital full-color copying machine according to an embodiment of the present invention.

FIG. 2 is a histogram showing the number of dots for each image density level of a document image acquired by a printer unit from a counter memory.

FIG. 3 is a diagram illustrating a relationship between a document image density and an image density level.

FIG. 4 is a diagram showing the relationship between the image density of a document and the amount of toner adhered on a photosensitive member.

FIG. 5 is a diagram illustrating a relationship between an image density level and a toner adhesion amount on a photoconductor.

FIG. 6 is a diagram illustrating an operation sequence of cleaning the transfer drum of the copying machine according to the present embodiment.

FIG. 7 is a flowchart illustrating a process of cleaning the transfer drum of the copying machine according to the present embodiment.

8 (a) to 8 (c) each show a predicted consumption integrated value,
FIG. 4 is a diagram illustrating a membership function of a fuzzy set of the number of multi-copy sheets and the amount of dirt in the apparatus.

FIGS. 9A and 9B are FIGS. 8A and 8B, respectively.
FIG. 11 is a diagram showing an example of determining the certainty factor of the state quantity using the membership function of FIG.

FIG. 10 is a diagram showing an inference rule used for estimating the amount of dirt in the copying machine.

FIG. 11 is a diagram illustrating a combination of certainty factors of an estimated amount of in-machine contamination.

FIG. 12 is a transparent perspective view of a charging charger.

FIG. 13 is a flowchart illustrating a process of cleaning a charged charge wire of the copying machine according to the present embodiment.

[Explanation of symbols]

1 Copying Machine (Image Forming Apparatus) 14 Image Signal Processing Unit (Toner Consumption Information Detection Unit,
Control means) 36 transfer drum 53 charging wire

Claims (6)

[Claims] 1. An image forming apparatus for forming an image by transferring a toner image formed by an electrophotographic method onto a recording medium, comprising: a toner consumption information detecting unit for detecting information relating to a toner consumption; An image forming apparatus comprising: a control unit configured to control an execution condition of a cleaning operation in the apparatus based on toner consumption amount information detected by the amount information detection unit. 2. The image forming apparatus according to claim 1, wherein the toner consumption information detection unit is a dot counter that counts the number of dots according to the density of a document image. 3. The control unit determines the execution condition of the cleaning operation in the apparatus based on the toner consumption information detected by the toner consumption information detection unit and the number of printed sheets after the previous cleaning operation in the apparatus. The image forming apparatus according to claim 1, wherein the control is performed. 4. The image forming apparatus according to claim 1, wherein the control unit controls an execution condition of the transfer drum cleaning operation. 5. The control device according to claim 1, wherein the control unit controls an execution condition of the charged charge wire cleaning operation.
The image forming apparatus according to claim 3. 6. The control means describes the toner consumption information and the transfer drum rotation number with a membership function, the antecedent of the inference rule is described with the toner consumption information and the transfer drum rotation number, and the consequent part. Using a fuzzy inference type rule described with an estimated value of contamination in the apparatus, the toner consumption information detected by the toner consumption information detecting means and the transfer drum rotation number after the previous cleaning operation in the apparatus are input values. By determining the estimated value of the consequent part by fuzzy inference including the min-max centroid method, and controlling the execution condition of the cleaning operation in the apparatus based on the estimated value. The image forming apparatus according to claim 1, wherein: