JP4957659B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for maximally utilizing a plurality of consumable components assembled in an image forming apparatus. <P>SOLUTION: The image forming apparatus having first and second consumable components includes: a first criterion for determining the degree of consumption of the first consumable component; a second criterion for determining the degree of consumption of the second consumable component; a first determining means for determining the degree of consumption of the first consumable component based on the first criterion; a second determining means for determining the degree of consumption of the second consumable component based on the second criterion; and a display section for displaying the result of the determination of the first and second determining means. The first criterion has, as a consumption degree criterion, an image quality warranty criterion corresponding to a consumption degree for warranting required image quality. When the first determining means determines that the consumption degree of the first consumable component has reached the image quality warranty criterion, the display section displays a warning of image quality degradation. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus including a plurality of consumable parts.

  The electrophotographic image forming apparatus includes various consumable parts, for example, a photoconductor and a developing device, and a reference value that must be exchanged is determined for each of the photoconductor and the developing device. In addition, in an image forming unit designed to integrate and replace a plurality of parts including a photoconductor and a developing device, a life criterion is set for each of the photoconductor and the developing device. The replacement of the image forming unit is urged based on the life criterion. For example, the life of the photosensitive member is managed based on the rotation time, and the life of the developing device is managed based on the driving time. The reason for this is that the charge holding capacity of the photoconductor decreases with an increase in the rotation time, and the efficiency of applying a charge to the developer decreases with an increase in the driving time of the photoconductor. This is because a phenomenon of soaking of the agent (so-called “fogging”) is caused.

  From this point of view, the photoconductor and the developing device have respective life values (reference values for prompting the user to exchange) and life stop values (to prohibit the use by the user) based on the rotation time and driving time. Standard value). However, the life value of the photoconductor and the life value of the developing device have different meanings. Specifically, the life value of the photoconductor is determined on the safer side so that fogging can be prevented by the charge holding capability of the photoconductor even when the developer reaches the life value and the charge imparting capability of the developer is reduced. ing. For this reason, even if the driving time of the developing device has reached the life value, if the rotation time of the photosensitive member has not reached the life value, an image without fogging can still be formed, and in this state, the image forming unit is sufficiently It can be used.

  However, in the conventional image forming apparatus, a warning is displayed to prompt the user to replace when the life of either the photoconductor or the developing device reaches the life value. Therefore, there may be a situation in which the image forming unit is replaced at an early stage even though it is actually usable.

  SUMMARY An advantage of some aspects of the invention is that it provides a mechanism capable of effectively using a plurality of consumable parts incorporated in an image forming apparatus as much as possible.

In order to achieve this object, the present invention provides an image forming apparatus including a photoconductor and a developing device.
Photoconductor consumption level determination means for determining the level of wear of the photoconductor based on a first determination criterion;
Developing device consumption level determination means for determining the consumption level of the developing device based on a second determination criterion;
A display unit for displaying determination results of the photoconductor consumption level determination unit and the developer unit consumption level determination unit;
As the first determination criterion, a second photosensitive element corresponding to a first photoconductor consumption level determination reference value corresponding to a consumption level that can guarantee a desired image quality and a consumption level for performing a display prompting the replacement of the photoconductor. The body wear level judgment reference value is set,
When the photoconductor wear level determination means determines that the photoconductor wear level has reached the first photoconductor wear level determination reference value, the display unit displays a warning that the image quality has deteriorated, and
The degree of consumption of the photosensitive member is determined using the rotation number of the photosensitive member, and the degree of consumption of the developing unit is determined using the number of prints of the developing unit, and the rotation number of the photosensitive member and the printing amount of the developing unit are determined. The second photoconductor consumption level determination reference value is determined by a function having the number of sheets as a variable ,
The photosensitive member and the developing device are integrated with the image forming unit so as not to be separated .

  According to the image forming apparatus having such a configuration, the display for warning the deterioration of the image quality is performed before the display for prompting the replacement of the consumable parts. It can warn of deterioration of image quality. For this reason, when the deterioration of the image quality is confirmed, it can be recognized that the cause is that the wear level of the consumable part is near the end of its life.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to the present invention. The illustrated image forming apparatus 10 is a so-called tandem type full-color printer. However, the image forming apparatus of the present invention is not limited to a printer, and includes various image forming apparatuses such as a copying machine, a facsimile machine, and a multifunction machine.

[1. Configuration and operation of image forming apparatus]
The configuration of the image forming apparatus 10 will be described together with a full-color image forming operation. For example, when a full-color image is formed using developers of four colors of yellow, magenta, cyan, and black (hereinafter referred to as “toner”), each of the four image forming units 12 corresponding to these four colors is used. A toner image corresponding to the color is formed. More specifically, each image forming unit 12 includes a photoconductor 14 and a developing device 16, and light emitted from an image exposure device (not shown) is irradiated onto each photoconductor 14 to cause an electrostatic latent image. Then, toner is supplied from the developing device 16 to the electrostatic latent image to form a toner image. The toner images formed by the image forming units 12 are sequentially transferred and superimposed on the endless transfer belt 18 to form a full-color toner image. Next, the full-color toner image is transferred to a medium (for example, paper) supplied from the paper supply unit 22 in a region where the transfer belt 18 and the transfer device 20 face each other. The medium onto which the toner image has been transferred is conveyed to the fixing device 24 where the toner image is heated and fixed and discharged to the paper discharge unit 26.

[2. (Image forming unit)
The image forming unit 12 includes a photosensitive member 14 and a developing device 16 integrally. In addition, the image forming unit 12 may be integrated with a charger for applying a charge to the photoconductor 14 and a collector (cleaner) for collecting untransferred toner from the photoconductor 14.

  Of these parts, the lifetimes of the photoreceptor 14 and the developing device 16 are managed by different parameters. For example, the life of the photosensitive member 14 is managed by its rotation time, and the life of the developing device 16 is managed by its driving time. The life management will be specifically described below.

[3. Life management)
The configuration of the image forming apparatus 10 and the image forming unit 12 related to the life management is shown in FIG. As illustrated, the image forming apparatus 10 includes a CPU 28, a ROM 30, a RAM 32, an I / O interface 34, display units 36 and 38, and a buffer memory 40, and the image forming unit 12 includes a memory 42. The memory 42 of the image forming unit 12 stores the rotational speed of the photosensitive member 14 and the driving time of the developing device 16 as information necessary for life management of the photosensitive member 14 and the developing device 16.

  With such a configuration, when the image forming unit 12 is attached to the image forming apparatus 10, the CPU 28 acquires the life information of the image forming unit 12 via the I / O interface 34. The acquired lifetime information is stored in, for example, the buffer memory 40, and the lifetime information is updated together with the image formation of the image forming apparatus 10. The updated lifetime information is transmitted to the memory 42 of the image forming unit 12 via the I / O interface 34, and the lifetime information in the memory 42 is updated. Therefore, for example, even when the image forming unit 12 is attached to or detached from one or a plurality of image forming apparatuses 10, the life information (consumption level) of the image forming unit 12 can always be managed.

[3.1: Overall control]
The overall control of the CPU 28 is shown in the flowchart of FIG. To explain in order along this figure, first, when the image forming apparatus 10 is connected to a power source, the CPU 28 acquires information necessary for image formation and the like from the ROM 30 and the RAM 32 and is incorporated in the image forming apparatus 10. Alternatively, the apparatus attached to the image forming apparatus 10 is initialized (S1). Next, necessary information is acquired from external devices (for example, a network, a computer, etc.) connected to the image forming apparatus 10 through the I / O interface 34 and necessary information is provided to these external devices (S2). ). Next, when a signal to start printing is input from the external device to the image forming apparatus 10 through the I / O interface 34, the CPU 28 executes a printing process (the above-described image forming process) (S4). When the printing process ends, other necessary processes (S5) are performed, and then a life determination process for each image forming unit 12 is performed (S6).

[3.2: Print control]
The specific processing content of the printing process (S3) is shown in the flowchart of FIG. In the printing process (S3), first, the state of the printing control status is determined. The print control status includes three statuses of “standby”, “printing”, and “printing completed”. If the print control status is “standby” now, processing (print activation processing) necessary to activate the electrophotographic process is executed (S302). Specifically, in the print activation process (S302), a process for rotating the photoreceptor 14 and a process for driving the developing device 16 are executed. Next, it is determined whether printing (image formation) in the image forming apparatus 10 is activated (started) (S303). If not activated, the status of “standby” is maintained, and if activated, the status is set to “standby”. “Medium” is changed to “Printing” (S304), the life management control (S311) is executed, and finally the other printing control (S312) is executed. As will be described later, in the life management process (S311), the life of the image forming unit 12 is determined based on the number of rotations of the photoconductor 14 and the driving time of the developing device 16.

  When the print control status is “printing”, the print process is executed (S305), the end of the print process is determined (S306), and when the print process is completed, the status is changed to “print end” (S307). Proceed to the life management control (S311). When the status is changed to “print end”, the print end process is executed (S308), it is determined whether the print end process is ended (S309), and when the print end process is ended, the status is set to “standby”. Change (S310) and proceed to life management control (S311).

[3.3: Life management control]
The specific processing contents of the life management control (S311) are shown in the flowchart of FIG. In the life management control (S311), it is determined whether or not the photoconductor 14 is rotating (S401). If the photoconductor 14 is rotating, the photoconductor rotation time is counted up (S402). The rotation time of the photoconductor is obtained, for example, by measuring the drive time of a motor (not shown) that drives the photoconductor 14 controlled by the CPU 28. Next, the life (degree of wear) of the photoconductor 14 is determined based on the rotation time of the photoconductor 14 (S403). As will be described later, the image forming apparatus 10 stores a plurality of stepwise life levels for determining the life of the photoconductor in the ROM 30, and based on these standards, the life level of the photoconductor 14 is determined. to decide. Next, the CPU 28 determines whether or not the printing process is completed (S404). When the printing process is completed, the CPU 28 counts up the number of printed sheets of the developing device 16 (S405). The number of printed sheets is almost proportional to the driving time of the developing device. Therefore, the lifetime of the developing device can be determined from the number of printed sheets of the developing device. Of course, the life of the developing device can be determined by measuring the rotation time (driving time) of a rotating body such as a developing roller housed in the developing device instead of the number of printed sheets. Next, the CPU 28 determines the life (consumption level) of the developing device 16 based on the number of printed sheets (driving time) of the developing device 16 (S406). As will be described later, the image forming apparatus 10 is provided with a plurality of life levels for determining the life of the developing device, and based on these criteria, the life level of the developing device 16 is determined. Finally, the CPU 28 determines the lifetime of the image forming unit 12 based on the lifetime determination results of the photoreceptor 14 and the developing device 16 (S407).

[3.4: Photoconductor lifetime judgment]
The specific processing content of the photoconductor lifetime determination (S403) is shown in the flowchart of FIG. In the photoconductor lifetime determination (S403), the photoconductor rotation time is acquired (S501), and it is determined whether the photoconductor rotation time exceeds the first, second, and third threshold values (photoconductor lifetime determination criteria). (S502, S503, S504). The first to third threshold values are determined in consideration of deterioration of only the photosensitive member (that is, assuming that there is no deterioration of the developing device), and the first threshold value is good for the photosensitive member (and the image forming unit). The second threshold is a criterion for prompting the user to replace the photoconductor (and the image forming unit), and the third threshold is forbidden to use the photoconductor (and the image forming unit). It is a standard to do. For example, the first threshold is set to “5400 minutes”, the second threshold is set to “5500 minutes”, and the third threshold is set to “5600 minutes”. If the photoconductor rotation time is less than the first threshold, the photoconductor lifetime level is “0” (S508), and if the photoconductor rotation time is greater than or equal to the first threshold and less than the second threshold, the photoconductor lifetime level. "1 (image quality warning)" (S507), if the photoconductor rotation time is greater than or equal to the second threshold and less than the third threshold, the photoconductor life level is set to "2 (life warning)" (S506). When the time reaches the third threshold value, the photoconductor life level is set to “3 (life stop)” (S505).

[3.5: Judgment of developer life]
The specific processing contents of the developer life determination (S407) are shown in the flowchart of FIG. In the developing device life determination (S407), the number of printed sheets of the developing device is acquired (S601), and it is determined whether or not the number of printed sheets of the developing device exceeds the first and second threshold values (developer life criterion) (S602). S603). The first and second threshold values are determined in consideration of deterioration of only the developing device (that is, assuming that there is no deterioration of the photoreceptor), and the first threshold value is replaced by the developing device (and the image forming unit). The second threshold is a standard for prohibiting the use of the developing device (and the image forming unit). For example, the first threshold value is set to “150,000 sheets” and the second threshold value is set to “160,000 sheets”. If the developing device printing number is less than the first threshold, the developing device life level is “0” (S606), and if the developing device printing number is greater than or equal to the first threshold and less than the second threshold, the developing device life level. Is set to “1 (life warning)” (S605), and when the number of prints on the developing device reaches the second threshold, the developer life level is set to “2 (life stop)” (S604).

[3.6: Lifetime determination of image forming unit]
The life determination of the image forming unit (S407) will be described with reference to the table of FIG. The ROM 30 of the image forming apparatus 10 stores data corresponding to the table of FIG. In this table, the horizontal axis represents the photoconductor life level (photoconductor rotation time), and the vertical axis represents the developer life level (number of printed sheets). Based on the combination of the photoconductor life level and the developer life level, The CPU 28 determines the life of the image forming unit 12.

  Specifically, when the photoconductor lifetime level is “0” and the developing device lifetime level is “0”, no warning is displayed. Hereinafter, the life level (unit life level) of the image forming unit is displayed by a symbol [X, Y] in which the photoreceptor life level “X” and the developing device life level “Y” are combined.

  When the unit life level is [1, 0], the CPU 28 displays “image quality warning” (actually, a corresponding symbol) on the first display unit 36 (see FIG. 2). The first display unit 36 is a display unit that is displayed by an operator (serviceman) operating an operation panel (not shown) of the image forming apparatus 10, and is not displayed in a normal use state. Therefore, in this state, the user cannot know that the life (consumption level) of the image forming unit 12 is out of the image quality guarantee range. However, when the user notices the image quality defect actually created by the image forming apparatus and notifies the operator, the operator activates the first display unit 36 and confirms whether or not there is an “image quality warning”, thereby causing the image quality defect. Can be known to be due to the life of the photoreceptor. Specifically, an example of the image quality warning of the first display unit 36 is shown in FIG. "L-1," "L-2," "L-3," and "L-4" displayed in this figure correspond to image forming units that use yellow, magenta, cyan, and black developers. “Image quality warning”.

  When the unit life level is [0, 1], the CPU 28 displays “life warning”) on the second display unit 38 (see FIG. 2). The second display unit 38 may display a “life warning” character or a corresponding symbol. Unlike the first display unit 36, the second display unit 38 is a warning display that is normally displayed on the operation panel of the image forming apparatus. Therefore, based on the life warning displayed on the second display unit 38 of the operation panel, the user can know that the life (replacement) of the image forming unit 12 is near.

  When the unit life level is [0, 2], the CPU 28 displays “stop warning”) on the second display unit 38 (see FIG. 2). The second display unit 38 may display a “stop warning” character or a corresponding symbol. Unlike the first display unit 36, the second display unit 38 is a stop display that is normally displayed on the operation panel of the image forming apparatus. Therefore, based on the stop warning displayed on the second display unit 38 of the operation panel, the user knows that the image forming unit 12 is in an unusable state.

  When the unit life level is [1, 0], the CPU 28 displays “image quality warning” on the first display unit 36 (see FIG. 2). When the unit life level is [1, 1] [1, 2], the CPU 28 displays “image quality warning” on the first display unit 36 (see FIG. 2), and “life warning” and “stop warning” respectively. 2 is displayed on the display unit 38. The “stop warning” may display the characters “stop warning” on the display unit, or may display a corresponding symbol. Therefore, based on the life warning displayed on the second display unit 38 of the operation panel, the user can know that the image forming unit 12 has reached the life (life level prompting replacement). Naturally, when the image forming apparatus 10 determines that the image forming unit 12 has reached the “stop warning” life level, a new image forming unit that has reached the life level is replaced with a new image forming unit. Prohibit image formation.

  Similarly, when the unit life level is [2, 0], [2, 1], [2, 2], the CPU 28 determines “image quality warning + life warning”, “image quality warning + life warning”, and “image quality warning +”, respectively. "Stop warning" is displayed. When the unit life level is [3, 0], [3, 1], [3, 2], the CPU 28 displays “image quality warning + stop warning”. That is, the “image warning” on the first display unit 36 and the “life warning” or “stop warning” on the second display unit 38 are performed, respectively. In the above-described example, the case where the first display unit 36 and the second display unit 38 are provided separately has been described. However, a specific mode based on a specific operation by the operator is provided with one display unit. When executed, display corresponding to the first display unit 36 may be performed on the display unit.

[3.7: Life judgment graph]
The usage tendency of image forming apparatuses varies greatly depending on the user. For example, in the case of an image forming apparatus used in an environment in which a relatively small number (1, 2) of printing is used, driving not related to actual printing such as an image formation start and stop sequence and image stabilization control Time is increased, and the life of the image forming unit is determined by the rotation time of the photosensitive member. FIG. 9 shows examples of warning display (life line) in various usage environments. Specifically, the life line A indicates a life line that may occur in a usage environment in which a large amount of printing is repeated. In the image forming apparatus that follows the life line A, “life warning” to “stop warning” are displayed. The In the image forming apparatus that follows the life line B, “life warning”, “image quality warning + life warning”, and “image quality warning + stop warning” are displayed. Further, in the image forming apparatus that follows the life line C, “image quality warning”, “image quality warning + life warning”, and “image quality warning + stop warning” are displayed.

[4: Other forms of life judgment graph]
In the above embodiment, the second threshold value for determining the life of the photoconductor is set to a specific rotation time. However, as shown in FIG. 10, the second threshold value can be given by a linear function or a curve function. In this embodiment, the function Z that defines the second threshold is expressed by the following Equation 1.

[5. Other Examples]
In the above description, the image forming unit is the one in which the photosensitive member 14 and the developing device 16 are integrally combined, but both may be separable. In this case, the photoconductor 14 and the developing device 16 can be replaced separately based on the respective life judgments. However, the image forming apparatus 10 can perform the above-described display based on the life levels of the photoreceptor 14 and the developing device 16.

  In the above description, the photosensitive member and the developing device are exemplified as the two consumable parts. However, it is possible to make a life determination by combining any two consumable parts and display the result on the display unit. For example, a combination of the transfer belt 18 and a heat fixing belt 24a (see FIG. 1) provided in the fixing device is also conceivable.

1 is a schematic cross-sectional view illustrating a configuration of a printer that is an example of image formation according to the present invention. FIG. 2 is a block diagram illustrating a configuration related to life determination of the printer illustrated in FIG. 1. 6 is a flowchart illustrating image forming processing of a printer. 6 is a flowchart showing print processing of a printer. 7 is a flowchart showing printer life management control. 6 is a flowchart showing determination of a photoconductor life of a printer. 6 is a flowchart showing a life of a developing device of a printer. The table | surface explaining the display content of the display part based on the lifetime of a photoconductor and a developing device. The figure which shows a lifetime determination graph. The figure which shows another lifetime determination graph. The figure which shows the display of a display part.

Explanation of symbols

10: Image forming apparatus 12: Image forming unit 14: Photoconductor 16: Developer 18: Transfer belt

Claims (6)

In an image forming apparatus including a photoconductor and a developing device,
Photoconductor consumption level determination means for determining the level of wear of the photoconductor based on a first determination criterion;
Developing device consumption level determination means for determining the consumption level of the developing device based on a second determination criterion;
A display unit for displaying determination results of the photoconductor consumption level determination unit and the developer unit consumption level determination unit;
As the first determination criterion, a second photosensitive element corresponding to a first photoconductor consumption level determination reference value corresponding to a consumption level that can guarantee a desired image quality and a consumption level for performing a display prompting the replacement of the photoconductor. The body wear level judgment reference value is set,
When the photoconductor wear level determination means determines that the photoconductor wear level has reached the first photoconductor wear level determination reference value, the display unit displays a warning that the image quality has deteriorated, and
The degree of consumption of the photosensitive member is determined using the rotation number of the photosensitive member, and the degree of consumption of the developing unit is determined using the number of prints of the developing unit, and the rotation number of the photosensitive member and the printing amount of the developing unit are determined. The second photoconductor consumption level determination reference value is determined by a function having the number of sheets as a variable ,
An image forming apparatus, wherein the photosensitive member and the developing unit are integrated with an image forming unit so as not to be separated . In an image forming apparatus including a photoconductor and a developing device,
Photoconductor consumption level determination means for determining the photoconductor consumption level based on a photoconductor consumption level determination criterion;
Developing device consumption level determination means for determining the consumption level of the developing device based on a developing device consumption level determination criterion;
A display unit for displaying determination results of the photoconductor consumption level determination unit and the developer unit consumption level determination unit;
As the photoconductor wear level determination criterion, a first photoconductor wear level determination reference value corresponding to a wear level capable of guaranteeing a desired image quality, and a second level corresponding to the wear level for performing a display prompting replacement of the photoconductor. And a third photoconductor wear level determination reference value corresponding to the wear level prohibiting the use of the photoconductor is set.
The developing device consumption level determination criterion includes a first developing device consumption level determination criterion corresponding to a consumption level for performing a display prompting replacement of the developing device, and a second corresponding to a consumption level for prohibiting use of the developing device. It is equipped with the criteria for determining the degree of wear of the developer.
When the photoconductor wear level determination means determines that the photoconductor wear level has reached the first photoconductor wear level determination reference value, the display unit displays a warning that the image quality has deteriorated, and
The degree of consumption of the photosensitive member is determined using the rotation number of the photosensitive member, and the degree of consumption of the developing unit is determined using the number of prints of the developing unit, and the rotation number of the photosensitive member and the printing amount of the developing unit are determined. The second photoconductor consumption level determination reference value is determined by a function having the number of sheets as a variable ,
An image forming apparatus, wherein the photosensitive member and the developing unit are integrated with an image forming unit so as not to be separated . The display unit includes a first display unit and a second display unit,
The display for warning the deterioration of the image quality is displayed on the first display unit, and the other determination results by the photoconductor consumption level determination unit and the developer unit consumption level determination unit are displayed on the second display unit. the image forming apparatus according to claim 1 or 2, characterized in that. The image forming apparatus has a specific operation mode,
Display to warn the deterioration of the image quality, the image forming apparatus according to any one of claims 1 to 3, characterized in that only appear during the execution of the specific operation mode. In an image forming apparatus including a photoconductor and a developing device,
The first photoconductor wear level determination reference value corresponding to the wear level that can guarantee the desired image quality, and the second photoconductor wear level determination reference value corresponding to the wear level that prompts replacement of the photoconductor. Based on the degree of wear of the photoconductor,
Determining the degree of wear of the developing device based on the criteria for judging the degree of developer consumption,
Display the determination result of the degree of wear of the photoconductor and the degree of wear of the developing unit on the display unit,
When it is determined that the degree of wear of the photoconductor has reached the first photoconductor wear level determination reference value, a display for warning of image quality deterioration is performed on the display unit,
The determination of the degree of consumption of the photoconductor is performed using the number of rotations of the photoconductor, and the determination of the degree of consumption of the developer is performed using the number of printed sheets of the developer,
The second photoconductor consumption level determination reference value is determined by a function having the number of rotations of the photoconductor and the number of printed sheets of the developer as variables ,
An image forming method, wherein the photosensitive member and the developing device are integrated in an image forming unit inseparably . In an image forming apparatus including a photoconductor and a developing device,
A first photoconductor wear level determination reference value corresponding to a wear level capable of guaranteeing a desired image quality, a second photoconductor wear level determination reference value corresponding to a wear level for performing a display prompting replacement of the photoconductor, and Determining the degree of wear of the photoconductor based on a third photoconductor wear level determination reference value corresponding to the degree of wear that prohibits the use of the photoconductor,
A first developer consumption level determination criterion corresponding to a consumption level for performing a display prompting replacement of the developer, and a second developer consumption level determination criterion corresponding to a consumption level for prohibiting use of the developer; To determine the degree of wear of the developer based on
Display the determination result of the degree of wear of the photoconductor and the degree of wear of the developing unit on the display unit,
When it is determined that the consumption level of the photoconductor has reached the first photoconductor consumption level determination reference value, the display unit warns the deterioration of image quality,
The determination of the degree of consumption of the photoconductor is performed using the number of rotations of the photoconductor, and the determination of the degree of consumption of the developer is performed using the number of printed sheets of the developer,
The second photoconductor consumption level determination reference value is determined by a function having the number of rotations of the photoconductor and the number of printed sheets of the developer as variables ,
An image forming method, wherein the photosensitive member and the developing device are integrated in an image forming unit inseparably .