JP2005178058A - Image forming apparatus, controller, quality assurance time limit calculation program, and quality assurance time limit calculation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate a quality assurance time limit of a process cartridge used in an image forming apparatus while use conditions are taken into account. <P>SOLUTION: Information of a manufacturing date, an attaching date, a deterioration coefficient and a tolerance limit value is inputted from a wireless IC tag fitted to the process cartridge (S20). Also the printing processing number of sheets for an attachment term while the image forming apparatus is recording is inputted (S24). Each of a deterioration degree before attachment which shows the deterioration in a packing state (S26), a non-working deterioration degree showing the deterioration in a non-working state after attachment (S28), and a working deterioration degree showing the deterioration in a working state (S30) is calculated. A total deterioration degree (S32) by summing each of these deterioration degrees is compared with the tolerance limit value, whereby the quality assurance time limit is calculated (S34). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for quality assurance of an image forming apparatus, and more particularly to a technique for quality assurance of a process cartridge attached to an image forming apparatus.

  In an image forming apparatus having a function of forming a printed image on a sheet such as a printer or a copier, a detachable process cartridge such as a drum unit or a toner cartridge is generally used. From the viewpoint of quality control of the printed image, it is desirable to be able to grasp the quality assurance period accompanying such process cartridge deterioration.

  Patent Document 1 below discloses a technique for storing information on the date of manufacture and warranty period in a memory attached to a process cartridge, and calculating the remaining days of use of the process cartridge based on this information and the calendar information of the apparatus. Has been.

JP-A-5-323716

  The degree of progress of deterioration of the process cartridge varies depending on the use state of the process cartridge. However, in the above-mentioned Patent Document 1, since the remaining number of days of use is determined based on the information on the guarantee period uniformly determined without considering the difference in the degree of progress, a reliable value cannot be obtained.

  An object of the present invention is to acquire information about a quality guarantee period in consideration of a difference in the degree of progress of deterioration depending on the use state of a process cartridge.

  Another object of the present invention is to acquire information about a quality assurance period by utilizing a memory attached to a process cartridge.

  The image forming apparatus of the present invention performs printing using the attached process cartridge, forms an image on a sheet, an acquisition unit that acquires past use history information of the process cartridge, A calculation unit that calculates the quality assurance period information of the process cartridge by estimating the degree of deterioration for each use state of the process cartridge based on the use history information.

  An image forming apparatus is an apparatus having a function of forming a print image on paper, such as a printer, a copier, or a facsimile. Various printing methods such as an electrophotographic method and an ink jet method can be adopted. The process cartridge is a component unit that is mounted on the image forming apparatus and used for printing processing. The acquisition unit can acquire use history information about the process cartridge. The information source may be a process cartridge storage unit, an image forming apparatus storage unit, an external device via a network, or a combination thereof. The usage history information is information that can analyze how the image forming apparatus has been used or how it has not been used.

  The calculating means calculates the quality assurance time limit information of the process cartridge by estimating the degree of progress of deterioration for each use state based on the use history information. The quality assurance period information is not information regarding a period when the process cartridge can be used but information regarding a period when certain quality is guaranteed. The quality assurance period information can be calculated by comparing the degree of deterioration with an appropriate reference value. As the reference value, for example, an acceptable limit value of the quality standard can be used. A plurality of reference values may be determined according to the application. The quality assurance deadline information obtained in this way can be expressed in various formats. For example, the quality guarantee deadline information may be expressed by the deadline for quality assurance, the remaining period, the remaining print processing quantity, etc., and the quality guarantee deadline has already passed. And information on quality level (degradation progress).

  According to this configuration, it is possible to calculate the quality assurance time limit information (for example, remaining life) of the process cartridge in consideration of the degree of progress of deterioration that varies depending on the use situation. Accordingly, it is possible to actually make a determination on the user side based on the allowable limit value intended by the manufacturer of the process cartridge, so that the reliability of the quality assurance period information can be improved. Furthermore, there is an effect that it is possible to prevent the waste of early replacement of the process cartridge due to erroneous calculation and the use outside the original quality guarantee period due to delayed replacement.

  Preferably, in the image forming apparatus of the present invention, the calculation unit estimates the quality assurance period information of the process cartridge by estimating at least a deterioration level before mounting and a deterioration level after mounting based on the use history information. calculate. Generally, a process cartridge is packaged and shipped so as to maintain a stable state, and the package is unpacked at the time of mounting. Therefore, the deterioration does not progress so much before mounting, but the deterioration progresses rapidly after mounting. Therefore, the calculation unit estimates the degree of deterioration before and after mounting separately based on the usage history information.

  Preferably, in the image forming apparatus according to the present invention, the calculation unit estimates at least a degree of deterioration in a non-printing process and a degree of deterioration in a printing process based on the use history information. The quality assurance deadline information is calculated. In general, a process cartridge is rapidly deteriorated due to being used for printing and actually operating. Therefore, the quality assurance deadline information can be calculated with high accuracy by separately estimating the degree of deterioration in the non-printing process and the degree of deterioration in the printing process.

  Desirably, in the image forming apparatus of the present invention, the calculation unit, based on the use history information, at least the degree of deterioration before mounting, the degree of deterioration in the non-printing process after mounting, and the process in the printing process By estimating the degree of deterioration, the quality assurance period information of the process cartridge is calculated. Deterioration does not progress so much before packing and the like in a good storage state. On the other hand, in a general environment after the package is unpacked, the progress of deterioration is accelerated even if the printing process is not performed. Further, in the print processing process after mounting, deterioration rapidly proceeds due to the load accompanying the print processing. Therefore, it is effective to estimate the degree of deterioration for each of the three usage situations. It should be noted that the deterioration in the non-printing process that proceeds in the attached state does not occur in the printing process (in other words, the deterioration is included in the deterioration in the printing process), or in the printing process. It may be considered that the process proceeds continuously (in other words, only deterioration caused by the printing process is included in the deterioration in the printing process).

  Preferably, in the image forming apparatus of the present invention, the calculation unit estimates each degree of deterioration based on a deterioration coefficient corresponding to an elapsed time in the usage state. The elapsed time may be acquired directly by the acquisition means, or may be calculated by acquiring start and end times and referring to calendar information. For example, in an image forming apparatus that is not frequently used, approximate calculation may be performed as appropriate, for example, by regarding the elapsed time in the non-printing process after mounting as approximately the elapsed time after mounting.

  The deterioration coefficient plays a role as a conversion function for converting the elapsed time into the deterioration degree. The deterioration coefficient is determined by conducting an experiment or the like. Acquired by storing in advance in the storage unit of the image forming apparatus, reading it via the network depending on the model number of the process cartridge, or incorporating it as attribute information in the storage unit of the process cartridge Can do. The deterioration coefficient does not need to be a constant, and may be a function of elapsed time or the number of processed sheets, for example.

  Desirably, in the image forming apparatus of the present invention, the calculation unit estimates at least one of the deterioration degrees in consideration of a temperature or humidity at which the process cartridge is placed in the usage state. The deterioration of the process cartridge varies depending on the use environment such as high temperature and low temperature, high quality and low humidity. Therefore, by detecting the temperature and humidity with a sensor or the like and incorporating them as use history information, the degree of deterioration can be calculated reflecting this use environment. The method of reflecting is not particularly limited. For example, a plurality of deterioration coefficients for calculating the deterioration degree from the usage elapsed time may be prepared and used depending on the use environment.

  Preferably, in the image forming apparatus of the present invention, the calculation unit estimates the degree of deterioration in the printing process based on a deterioration coefficient corresponding to the number of printing processes. The print processing quantity refers to the number of sheets subjected to the printing process, the number of rotations of the drum, and the like. The elapsed time in the printing process may be calculated based on the printing process quantity.

  Preferably, in the image forming apparatus of the present invention, the process cartridge includes a storage unit that records use history information of the process cartridge, and the acquisition unit acquires the use history information from the storage unit. The storage unit of the process cartridge can be mounted by a nonvolatile memory or the like. This memory access method may be a contact type or a non-contact type (using electromagnetic waves or the like). In the storage unit, usage history information such as the manufacturing time and the mounting time can be recorded, and the product model number, information on the deterioration coefficient, and the like can also be recorded. In this manner, by attaching the storage unit to the process cartridge itself, it becomes possible to accurately manage each process cartridge, and it becomes possible to easily elucidate the problem and identify the location of responsibility.

  Preferably, in the image forming apparatus of the present invention, the image forming apparatus includes a storage unit that records use history information of the process cartridge, and the acquisition unit acquires the use history information from the storage unit. The storage unit of the image forming apparatus can usually be mounted by a semiconductor memory, a hard disk, or the like. For example, when the process cartridge is mounted, the time is recorded in the storage unit, so that mounting time information as use history information can be input. It is also effective to store, as usage history information, the number of prints processed after the process cartridge is replaced. It is also possible to record information on the deterioration coefficient in the storage unit of the image forming apparatus. Note that the usage history information can be allocated and stored in both the storage unit of the process cartridge and the storage unit of the image forming apparatus. In that case, which information is stored in which storage unit can be arbitrarily set.

  Desirably, in the image forming apparatus of the present invention, the image forming means performs electrophotographic printing processing, and the process cartridge includes a drum unit including a photosensitive drum on which an electrostatic latent image is formed by a light beam, At least one of a developing unit that develops the electrostatic latent image, a toner cartridge that stores toner used for development, a transfer unit that transfers the toner on the photoreceptor onto the paper, and a fixing unit that fixes the toner transferred onto the paper including. Some of these may be combined to form one process cartridge.

  A control device of the present invention is a control device that controls an image forming system that includes an image forming unit that performs a printing process using a mounted process cartridge and forms a printed image on a sheet. Acquisition means for acquiring past use history information; and calculation means for calculating quality assurance time limit information of the process cartridge by estimating a deterioration degree for each use state of the process cartridge based on the use history information. Prepare. The control device may be incorporated in the image forming system in the form of an ASIC (application-specific integrated circuit), or may be provided as a separate casing PC (personal computer).

  The quality assurance expiration date calculation program according to the present invention is a program executed by an image forming system including an image forming unit that performs a printing process using a mounted process cartridge and forms a print image on a sheet. An acquisition procedure for acquiring past use history information of a process cartridge, and a calculation procedure for calculating quality assurance expiration date information of the process cartridge by estimating a degree of deterioration for each use state of the process cartridge based on the use history information And including.

  The quality assurance expiration date calculation method of the present invention is a method executed by an image forming system including an image forming unit that performs a printing process using a mounted process cartridge and forms a print image on a sheet. An acquisition step of acquiring past use history information of the cartridge, and a calculation step of calculating the quality assurance expiration date information of the process cartridge by estimating the degree of deterioration for each use state of the process cartridge based on the use history information ,including.

  Hereinafter, typical embodiments of the present invention will be described.

  FIG. 1 is a schematic block diagram showing a functional configuration of the image forming apparatus according to the present embodiment. The image forming apparatus 10 is an apparatus having a function of forming a print image on paper such as paper, and specifically corresponds to a printer, a copier, or the like.

  The image forming unit 12 is provided to perform this image forming process, and forms a print image on the conveyed paper by an electrophotographic method based on electronic image data. A characteristic point of the image forming unit 12 is that it includes a process cartridge group 14 including a plurality of process cartridges that are detachably mounted. Specifically, as a process cartridge, a drum unit 16 including a photosensitive drum on which an electrostatic latent image is formed by a light beam, a developing unit 18 that develops the electrostatic latent image on the photosensitive drum, and a toner used for development. A stored toner cartridge 20, a transfer unit 22 for transferring the toner on the photosensitive member to a sheet, and a fixing unit 24 for fixing the toner transferred to the sheet are provided.

  Each process cartridge group 14 has a time limit (life) in which the quality is guaranteed, and when the process cartridge 14 has reached its life, it is promptly replaced with a new one. It should be noted that this quality assurance period is different from, for example, that the toner cartridge 20 is in an unusable state when the toner is used up. The toner reduction is basically determined only by the print processing amount, and it is not necessary to guarantee the quality of the remaining amount of toner or out of toner. What is meant by the term “quality guarantee period” is a period when the quality of the toner or the quality of the printed image is no longer guaranteed. For example, in the case of the drum unit 16, the photosensitive drum is worn and deteriorated by the cleaning blade, and also deteriorated due to heat, light, and the like. Therefore, the quality assurance deadline is calculated by considering the amount of wear corresponding to the number of prints processed (the number of rotations of the drum) and the deterioration state due to heat or the like. Similarly, the quality assurance deadlines of the developing unit 18, the transfer unit 22, and the fixing unit 24 are determined in consideration of deterioration related to factors such as temperature, humidity, oxidation, wear, and consumption.

  Each process cartridge is provided with wireless IC tags 26, 28, 30, 32, and 34 that each have a non-volatile memory and can input / output data without contact. In the shipping stage, each IC tag 26-34 receives and stores a deterioration coefficient for converting the elapsed time into the degree of progress of deterioration, in addition to the product number and manufacturing date information of each process cartridge. A plurality of deterioration factors are stored for each use situation. Further, when the process cartridge is mounted on the image forming apparatus 10, information on the mounting date is input, and when the process cartridge is removed from the image forming apparatus 10, information on the date of removal is input and stored. The The image forming unit 12 is further provided with a temperature / humidity sensor 36 and a counter 38. The temperature / humidity sensor 36 is a temperature sensor and a humidity sensor that monitor the usage environment of the process cartridge group 14. In particular, since the deterioration of the toner cartridge 20 greatly depends on the temperature and humidity, it is valuable to detect the temperature and humidity. The counter 38 counts the number of sheets to be printed in the image forming unit 12. The detected temperature and humidity and the counted number of print processes are recorded in the storage unit 46 described later.

  The image forming apparatus 10 further includes a communication unit 40, a time management unit 42, a control unit 44, a storage unit 46, an input / output unit 48, a UGI unit 50, and a calculation unit 52. The communication unit 40 communicates with the wireless IC tags 26, 28, 30, 32, and 34 provided in each process cartridge, and inputs and outputs data. The time management unit 42 has a calendar function and outputs the current date and time. The control unit 44 controls the operation of each component of the image forming apparatus 10 with hardware having a calculation function and software (program) that defines the calculation operation. The storage unit 46 includes a semiconductor memory, a hard disk, and the like, and stores various data, programs, and the like. The input / output unit 48 inputs / outputs data and command signals to / from an external device via the network 60. The UGI unit 50 includes a display unit such as a display and a user input function from the display screen, and outputs information to the display unit or accepts user input. Similar to the control unit 44, the calculation unit 52 is configured by hardware having a calculation function and software (program) that defines the calculation operation, and is a quality guarantee that is a time limit for guaranteeing the quality of the process cartridge group 14. Information related to the deadline is calculated.

  Here, a state in which the wireless IC tag 26-34 is used will be described with reference to FIG. FIG. 2 is a flowchart for explaining a process of using a certain process cartridge and a wireless IC tag provided thereon. First, at the stage when this process cartridge is manufactured, the product number, date of manufacture, deterioration factor, allowable limit value that is the limit value of the deterioration level that can be guaranteed quality, and the like are stored in the memory of the wireless IC tag. (S10). Then, the process cartridge is sealed and packed and shipped as a product (S12). When the user of the image forming apparatus 10 starts using the image forming apparatus 10 or replaces the process cartridge, the user unpacks the process cartridge and attaches it to the image forming apparatus 10 (S14). At this time, the mounting date is input to the memory of the wireless IC tag by the communication unit 40 (S16). When the calculation unit 52 calculates the quality assurance time limit information, the communication unit 40 reads the date of manufacture, date of installation, deterioration factor, and allowable limit value from the memory of the wireless IC tag (S18). . In addition, when it removes and re-installs once after mounting | wearing, the date of removal and the date of re-mounting are also read.

  Next, a process in which the calculation unit 52 calculates the quality assurance time limit information will be described using the flowchart of FIG. First, at the timing when the calculation unit 52 calculates, the IC tag of the process cartridge for which the manufacturing date and the mounting date as the use history information are calculated is read through the communication unit 40. At the same time, the deterioration coefficient and the allowable limit value are read (S20). The current date is input from the time management unit 42 (S22). Then, the number of sheets printed during the period from the installation date to the current date is also input from the storage unit 46 as usage history information (S24).

  The calculation unit 52 calculates the elapsed time before mounting based on the manufacturing date, the mounting date, and the calendar information of the time management unit 42. Then, by multiplying the pre-mounting deterioration coefficient by the pre-mounting elapsed time, the pre-mounting deterioration degree, which is the degree of deterioration before the mounting, is calculated (S26). Further, the non-operating time (non-printing processing time) after mounting is calculated based on the mounting date, the current date, and calendar information, assuming that the elapsed time after mounting is approximately. Then, by multiplying the non-operating deterioration coefficient after mounting by the non-operating time, a non-operating deterioration degree that is a degree of deterioration in the non-operating time is calculated (S28). Further, by multiplying the deterioration coefficient for the number of print processing sheets by the number of print processing sheets, an operation deterioration degree that is a degree of deterioration during operation is calculated (S30). Finally, the total deterioration degree of the process cartridge is calculated by adding the deterioration degree before mounting, the non-operation deterioration degree, and the operation deterioration degree (S32).

  The calculation unit 52 compares the total deterioration level with an allowable limit value (S34). Then, it is detected whether the continuous use is possible without exceeding the allowable limit value. If it can be used continuously, the remaining number of printable sheets is calculated. This calculation can be performed, for example, by calculating “(allowable limit value−total deterioration degree) / deterioration coefficient for the number of print processed sheets”. Of course, the remaining printable number of sheets may be calculated based on the average degree of deterioration in the past certain period, taking into account that the deterioration proceeds during non-operation. Similarly, the remaining printable time can be calculated.

  The calculated result is displayed on the display and, if necessary, output to an external device through the input / output unit 48 (S36). As a result, for example, the administrator or maintenance / inspection worker of the image forming apparatus 10 can accurately grasp information such as the necessity of replacing the process cartridge. It should be noted that this series of processing for calculating the degradation state can be executed according to an instruction from an administrator or the like, or can be automatically performed at regular intervals. Moreover, when the allowable limit value is approached, it may be set to be executed frequently.

  Next, the progress of deterioration will be specifically described with reference to FIGS.

  4, 5, and 6 show the elapsed time in the packing state (before mounting), the assembled state (non-printing processing state after mounting), and the actual operation state (printing processing state after mounting), respectively. It is the schematic diagram which showed the correspondence of deterioration degree. In the packaged state of FIG. 4, the slope α of the graph is small, indicating that the progress of deterioration is very slow over time. For example, in the case of the drum unit 16, the allowable limit value is not reached even after 5 years in the packaged state. On the other hand, in the built-in state of FIG. 5, the slope β of the graph is larger than α due to factors such as heat, humidity, and oxidation, and the progress of deterioration is slightly faster over time. In the case of the drum unit 16, the time required to reach the allowable limit value in the non-operating state is, for example, one year. In the actual operating state of FIG. 6, the slope γ of the graph is further larger than β due to the influence of wear and consumption, and the degree of deterioration rapidly increases with time (this is also an increase in the number of prints). Increase. The time required to reach the allowable limit value depends largely on the printing speed and the number of sheets that can be processed, but is generally about 20 to 50 hours (about 100,000 sheets).

  As can be seen, it is important to consider the history of how the process cartridge has been used, not just based on the elapsed time from the date of manufacture. In particular, in order to obtain accurate information on the quality assurance period of the process cartridge in both an image forming apparatus that is frequently used and an image forming apparatus that is not frequently used, it is necessary to carefully consider the use situation.

  FIG. 7 is a schematic graph showing the progress of the deterioration degree with respect to the passage of time from the date of manufacture. During the period from the date of manufacture to the date of attachment, the deterioration proceeds as shown by the line 80 having the slope α shown in FIG. For example, in the case of the drum unit 16, this period is about 1 to 6 months, although it varies depending on the distribution period and the user storage period. This period is sufficiently smaller than the period of about 5 years to reach the allowable limit value, and the degree of deterioration hardly increases.

  On the other hand, after the mounting date, the deterioration progresses with the inclination β shown in FIG. 5 when not in operation and with the inclination γ shown in FIG. 6 when in operation. For example, immediately after the mounting date, the non-operating state continues for a while, and the degree of deterioration increases according to the line 82 having the slope β. With the operation, the deterioration rapidly progresses according to the line 84 having the inclination γ, and the deterioration progresses again according to the line 86 having the inclination β with the end of the operation. In this way, the deterioration degree eventually reaches the allowable limit value by repeating the operation state and the non-operation state. This is the date when quality is guaranteed. The calculation unit 52 checks whether or not the allowable limit value has been reached, and calculates the remaining days until the quality assurance date and the remaining printable number of prints.

  It should be noted that the above processing can be implemented with various modifications. For example, manufacturing date information and deterioration coefficient information once acquired from the wireless IC tag 26-32 are recorded in the storage unit 46 of the image forming apparatus 10, and thereafter the information may be acquired from the storage unit 46. it can. Further, if the result of once calculating the degree of deterioration before mounting is recorded in the storage unit 46, the time for recalculation can be shortened.

It is a schematic functional block diagram which shows the apparatus structure of this Embodiment. It is a flowchart which shows the input / output to the memory | storage part of a process cartridge. It is a flowchart which shows the process which calculates quality assurance term information. It is a typical graph which shows the progress of deterioration before wearing. It is a typical graph which shows the progress of the deterioration in the non-operating state after mounting | wearing. It is a typical graph which shows the progress of deterioration in an operation state. It is a typical graph which shows the progress of deterioration under an actual condition.

Explanation of symbols

  10 image forming apparatus, 12 image forming unit, 14 process cartridge group, 16 drum unit, 18 developing unit, 20 toner cartridge, 22 transfer unit, 24 fixing unit, 26 tag, 36 temperature / humidity sensor, 38 counter, 40 communication unit, 42 time management unit, 44 control unit, 46 storage unit, 48 input / output unit, 50 UGI unit, 52 calculation unit, 60 network.

Claims (13)

An image forming unit that performs a printing process using the mounted process cartridge and forms a print image on paper;
Obtaining means for obtaining past use history information of the process cartridge;
A calculation unit that calculates the quality assurance time limit information of the process cartridge by estimating the degree of deterioration for each use state of the process cartridge based on the use history information;
An image forming apparatus comprising: The image forming apparatus according to claim 1.
The image forming apparatus characterized in that the calculation unit calculates the quality assurance period information of the process cartridge by estimating at least a deterioration level before mounting and a deterioration level after mounting based on the use history information. . The image forming apparatus according to claim 1.
The calculating unit calculates the quality assurance period information of the process cartridge by estimating at least a deterioration degree in a non-printing process and a deterioration degree in a printing process based on the use history information. An image forming apparatus. The image forming apparatus according to claim 1.
The calculation unit estimates at least the degree of deterioration before mounting, the degree of deterioration in the non-printing process after mounting, and the degree of deterioration in the printing process based on the use history information, An image forming apparatus, characterized in that quality guarantee term information is calculated. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the calculation unit estimates each degree of deterioration based on a deterioration coefficient corresponding to an elapsed time in the usage state. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the calculation unit estimates at least one of the deterioration levels in consideration of a temperature or humidity at which the process cartridge is placed in a use state. The image forming apparatus according to claim 3 or 4, wherein:
The image forming apparatus, wherein the calculation unit estimates a degree of deterioration in the printing process based on a deterioration coefficient corresponding to a print processing quantity. The image forming apparatus according to claim 1.
The process cartridge includes a storage unit that records use history information of the process cartridge,
The image forming apparatus, wherein the acquisition unit acquires the use history information from the storage unit. The image forming apparatus according to claim 1.
The image forming apparatus includes a storage unit that records use history information of the process cartridge,
The image forming apparatus, wherein the acquisition unit acquires the use history information from the storage unit. The image forming apparatus according to claim 1.
The image forming unit performs a printing process by an electrophotographic method,
The process cartridge is
A drum unit including a photosensitive drum on which an electrostatic latent image is formed by a light beam;
A development unit for developing an electrostatic latent image;
A toner cartridge storing toner used for development,
A transfer unit for transferring the toner on the photoreceptor onto the paper;
A fixing unit for fixing the toner transferred to the paper,
An image forming apparatus comprising at least one of the following. A control device that controls an image forming system including an image forming unit that performs a printing process using a mounted process cartridge and forms a printed image on a sheet,
Obtaining means for obtaining past use history information of the process cartridge;
Calculation means for calculating the quality assurance period information of the process cartridge by estimating the degree of deterioration for each use state of the process cartridge based on the use history information;
A control device comprising: A program executed by an image forming system including an image forming unit that performs a printing process using a mounted process cartridge and forms a print image on a sheet,
An acquisition procedure for acquiring past use history information of the process cartridge;
A calculation procedure for calculating the quality assurance period information of the process cartridge by estimating the degree of deterioration for each use state of the process cartridge based on the use history information;
A quality assurance expiration date calculation program characterized by including: A method executed by an image forming system including an image forming unit that performs a printing process using a mounted process cartridge and forms a print image on a sheet,
An acquisition step of acquiring past use history information of the process cartridge;
A calculation step of calculating the quality assurance period information of the process cartridge by estimating the degree of deterioration for each use state of the process cartridge based on the use history information;
A quality assurance expiration date calculation method comprising:

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