Patent Publication Number: US-9904227-B2

Title: Image forming apparatus, consumable product management method, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an image forming apparatus that can manage replacement history of a consumable product, such as a toner cartridge. 
     Description of the Related Art 
     A recent image forming apparatus that uses a toner cartridge, which integrates a photosensitive drum, a development device, and toner particles, as a consumable product, is generally known. In general, a manufacturer of the image forming apparatus provides genuine toner cartridges. On the other hand, reused toner cartridges have been showing up in the market and are available from outsiders. The reused toner cartridge can be manufactured by replenishing a used toner cartridge with new toner particles. The reused toner cartridge is different in toner components from the genuine toner cartridge provided by the manufacturer of the image forming apparatus. Therefore, differences may appear in printing results. The reused toner cartridge may cause a failure or malfunction in a printer body. 
     An image processing apparatus discussed in Japanese Patent Application Laid-Open No. 2008-250087 can record a history of toner cartridge having been used by a user (or a plurality of users) and can display the recorded history for the purpose of maintenance/guarantee of the apparatus. However, to assure the reliability of the above-mentioned use history record, it is necessary to surely detect a true replacement of toner cartridge. In this respect, the conventional image processing apparatus determines whether toner cartridge has been replaced by simply comparing serial numbers recorded in nonvolatile memories (Hereinbelow, referred to as “memory tags”) attached to respective toner cartridges and records a detection result as a history. 
     The contents recorded in the memory tag attached to the toner cartridge include information necessary to maintain printing qualities in addition to the above-mentioned serial number. There is a reused cartridge to which a copied memory tag is attached. In this case, the reused cartridge can hold contents identical to those of a memory tag attached to a brand-new toner cartridge. 
     If such a reused toner cartridge is actually used, it is difficult to detect a true replacement of toner cartridge based on a comparison of the serial numbers because the copied memory tag of the reused toner cartridge is identical to that of the brand-new toner cartridge. 
     The above-mentioned problem is not limited to toner cartridges and will occur in any other consumable products respectively equipped with a memory tag (i.e., serial number holding unit). 
     The present invention is directed to an image forming apparatus that can accurately detect a replacement of consumable products that are identical to each other in serial number and can accurately manage information relating to the replaced consumable product. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, an image forming apparatus that can form an image by using a consumable product that holds individual information including at least one of reference date and time and use record value, wherein the image forming apparatus includes at least one processor and at least one memory coupled to the at least one processor, and the at least one processor and the at least one memory act as a reading unit configured to read the individual information from a memory of the consumable product, a memory configured to store the read individual information, and a control unit configured to perform a first control or a second control, in which the first control includes adding the individual information read from the memory of the consumable product, as new individual information, to the memory of the image forming apparatus based on a comparison between the reference date and time included in the individual information held in the memory of the consumable product and reference date and time included in individual information stored in the memory of the image forming apparatus, and the second control includes adding the individual information read from the memory of the consumable product, as new individual information, to the memory of the image forming apparatus based on a comparison between the use record value included in the individual information held in the memory of the consumable product and use record value included in the individual information stored in the memory of the image forming apparatus. 
     According to another aspect of the present invention, an image forming apparatus for forming an image that can form an image by using a consumable product that holds individual information including at least one of reference date and time and use record value, includes a reading unit configured to read the individual information from a memory of the consumable product, a device built-in memory that stores the individual information, and a control unit configured to compare the individual information held by the consumable product and the individual information recorded in the device built-in memory and adds the individual information read from the consumable product to the device built-in memory as new individual information, in a case where a difference between the two pieces of the individual information exceeds a predetermined range. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating an internal configuration of a printer according to an exemplary embodiment. 
         FIG. 2  is a block diagram illustrating a hardware configuration of a control system of the printer. 
         FIG. 3  is a block diagram illustrating a functional configuration of a controller. 
         FIG. 4  is a block diagram illustrating a memory structure of a memory tag. 
         FIG. 5  is a block diagram illustrating an example of cartridge information recorded in a device built-in memory. 
         FIG. 6  is a table illustrating a printed example of replacement history of the cartridge information. 
         FIG. 7  is a flowchart illustrating a procedure of printed page counter update processing. 
         FIG. 8  is a flowchart illustrating a procedure of cartridge replacement detection processing according to a first exemplary embodiment. 
         FIG. 9  is a flowchart illustrating a procedure of cartridge replacement detection processing according to a second exemplary embodiment. 
         FIG. 10  is a flowchart illustrating a procedure of cartridge replacement detection processing according to a third exemplary embodiment. 
         FIG. 11  is a flowchart illustrating a procedure of cartridge replacement detection processing according to a fourth exemplary embodiment. 
         FIG. 12  is a table illustrating life alarm history information determination standards according to the fourth exemplary embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinbelow, a first exemplary embodiment will be described in detail below with reference to attached drawings. 
     &lt;Configuration of Image Forming Apparatus&gt; 
     First, an image forming apparatus according to the present exemplary embodiment will be described in detail below. The image forming apparatus includes a laser beam printer (Hereinbelow, referred to as “printer”).  FIG. 1  illustrates an internal cross-sectional configuration of a printer  200 . The printer  200  includes a plurality of paper feeder cassettes  511 , an image forming unit  507 , a main conveyance path  540 , and a discharge conveyance path  541 . The printer  200  further includes a plurality of rollers (e.g., feed rollers  502 , conveyance rollers  510 , registration rollers  504 , and discharge rollers  520 ), which is provided along respective conveyance paths, to convey a sheet  503  (i.e., paper or recording material) on which an image is to be formed. The printer  200  further includes a plurality of sensors (e.g., paper feeding cassette paper presence sensors  501 , a registration sensor  505 , a paper detection sensor  506 , and a discharge sensor  508 ), to detect the sheet  503  in the apparatus. Each paper feeder cassette  511  functions as a feed unit configured to supply the sheet  503  in the apparatus. 
     The image forming unit  507  is a consumable product that includes an exposure unit, a photosensitive drum, and a developing unit, which are incorporated in a replaceable casing that is attachable to and detachable from an apparatus main body, to form an image on the sheet  503 . The consumable product is, for example, a toner cartridge  224  (described below), which includes an information holding unit and a residual quantity detection sensor that can detect the residual quantity of filled toner. The image forming unit  507  causes the exposure unit to form an electrostatic latent image on the photosensitive drum (i.e., an image bearing unit). The electrostatic latent image can be formed based on image data received by a controller  210  (described below) from an external device. The developing unit develops the electrostatic latent image formed by the image forming unit  507 . More specifically, toner particles are attached to the electrostatic latent image and transferred to a sheet at a predetermined transfer position. The transferred image is referred to as a toner image. A fixing apparatus (not illustrated) can fix the toner image formed on the sheet by heating and pressing the sheet (i.e., paper or recording material). 
     The main conveyance path  540 , along which an image can be formed on the sheet  503 , extends from the feed rollers  502  to the discharge rollers  520 . The conveyance rollers  510  constitute a part of the paper feeder cassette  511 . Therefore, the paper conveyance path from a lower paper feeder cassette  511  is disconnected when an upper paper feeder cassette  511  is pulled out. The discharge conveyance path  541  is a conveyance path along which the sheet  503  can be discharged from the discharge rollers  520  to the outside of the printer  200 . The feed rollers  502  can successively convey the sheets  503  stacked on the paper feeder cassette  511  to the inner side of the apparatus. The registration rollers  504  can adjust the timing at which the image forming unit  507  transfers an image to the conveyed sheet  503 . The discharge rollers  520  discharge the sheet  503  to the outside of the printer  200 . 
     The paper presence sensor  501  can detect the presence of the sheet  503  stacked on the paper feeder cassette  511 . Each of the registration sensor  505 , the paper detection sensor  506 , and the discharge sensor  508  can detect the conveyed sheet. These sensors can be mechanical switches or optical sensors. The registration sensor  505  is used to adjust the timing at which the toner image formed on the photosensitive drum is transferred to the conveyed sheet  503 . The registration sensor  505  is used as a sensor capable of measuring the length of the sheet  503  in a sub scanning direction. The length of the sheet  503  in the sub scanning direction is obtainable based on the time during which the registration sensor  505  keeps detecting the conveyed sheet  503  and the conveyance speed of the sheet  503 . The paper detection sensor  506  is used to detect the presence of the sheet  503  at both end portions of the main conveyance path  540 . The paper detection sensor  506  is usable as a sensor for obtaining the length of the sheet  503  in a main scanning direction. 
     &lt;Control System&gt; 
       FIG. 2  is a block diagram illustrating an example configuration of a control system of the printer  200 . The control system is constituted by the controller  210  and peripheral devices. The controller  210  is a computer including a central processing unit (CPU)  201 , a random access memory (RAM)  202 , a read only memory (ROM)  203 , and an electrically erasable programmable read only memory (EEPROM)  204 , which are connected to each other via a system bus  209 . The controller  210  can function as a control unit. The CPU  201  can execute computer programs according to the present exemplary embodiment to access and control various devices connected to the system bus  209 . The RAM  202  can function as a main memory and/or a work area of the CPU  201 . The RAM  202  can expand its memory capacity if an optional RAM is connected to an extension port (not illustrated). The RAM  202  is usable as a drawing memory that can store image data received from an external device, or usable as a video signal ON/OFF information storage area or other work areas. The ROM  203  is a program ROM, which can store the above-mentioned control programs. The EEPROM  204  is a nonvolatile memory, which can store management information including individual information and replacement history unique to the toner cartridge  224  (described below). The EEPROM  204  can be replaced by any other nonvolatile memory, such as a Flash ROM or an embedded Multi Media Card (eMMC). In the following description, such a nonvolatile memory is referred to as “device built-in memory.” A printing unit interface (I/F)  205 , a panel I/F  206 , a memory controller  207 , and a network controller  208  are connected to the system bus  209 . 
     The printing unit I/F  205  can transmit and receive print related information to and from a printing mechanism unit  220 . The printing mechanism unit  220  corresponds to the printer  200  illustrated in  FIG. 1 . The panel I/F  206  can transmit and receive information to and from an operation panel  221 . The memory controller  207  can control an access to a hard disk drive (HDD)  222 . The network controller  208  can control a network communication module  223  to communicate with various information terminals via the network. 
     The printing mechanism unit  220  can access a memory tag  225  attached to the toner cartridge  224  that is filled with toner particles. In other words, the printing mechanism unit  220  can function as a reading unit configured to cause the controller  210  to read individual information from the memory tag  225 . Further, the printing mechanism unit  220  can function as an update unit configured to update the individual information recorded in the memory tag  225  controlled by the controller  210 . The operation panel  221  includes various operation switches and LED indicators. The CPU  201  can control the operation panel  221  via the panel I/F  206 . 
       FIG. 3  is a block diagram illustrating a functional configuration of the controller  210  that can be realized when the CPU  201  executes the control programs. The controller  210  includes an interface (I/F)  301 . The I/F  301  is an interface connected to a host computer  100 , which can function as a server or a client. The host computer  100  can output print information, which includes print data and control codes, to the controller  210 . A receiving buffer  302  can successively store print information received via the I/F  301 . Then, if necessary, a command analyzing unit  306  or an image control unit  304  can read the print information from the receiving buffer  302  and process the print information. 
     The command analyzing unit  306  can analyze commands included in the print information. The commands analyzed by the command analyzing unit  306  include commands relating to image data (e.g., bitmap data), which give instructions to the image control unit  304 . On the other hand, commands not relating to drawing (e.g., feeding paper selection, reset command) give instructions to the print control unit  307 . The image control unit  304  can perform predetermined image processing on image data transferred from the receiving buffer  302  with the instructions from the command analyzing unit  306 . Further, the image control unit  304  can store processing results in an image buffer  305 . A status management unit  308  can determine an operational state (status) of the printer  200  based on information from the print control unit  307 . Further, the status management unit  308  can cause the operation panel  221  to display the state of the printer  200  and can return acquired status information in response to a status information acquisition command issued from the host computer  100 . The status management unit  308  can transmit the status information to the host computer  100  via the command analyzing unit  306 , a transmission buffer  303 , and the I/F  301 . An output control unit  309  can convert image data stored in the image buffer  305  into a video signal, and can transfer the video signal to the printing mechanism unit  220 . The printing mechanism unit  220  is a printer engine that can form a permanently visual image based on the received video signal and can transfer the formed image to a sheet. 
     A cartridge management unit  310  can manage individual information unique to the toner cartridge  224  in corporation with the printing mechanism unit  220  and the memory tag  225 . The individual information includes a serial number (i.e., identification information unique to the toner cartridge  224 ), reference date and time, operating results value, and device serial number. The individual information is not limited to the above-mentioned example and can be modified in such a way as to include at least one of the reference date and time and the use record value. The use record value is, for example, a printed page count value that changes according to the use record value, which does not decrease unless it is reset. In this respect, the use record value is greatly different from life information (life span) discussed in Japanese Patent Application Laid-Open No. 2008-250087. The reference date and time can used to manage the toner cartridge  224 . For example, the reference date and time is time information about initial usage and time information about final usage (updated). The time information is information derived from a clocking function (i.e., one of standard functions) of the controller  210  (i.e., the CPU  201 ) and can be measured using a clock frequency of several seconds or less. The device serial number is identification information about an apparatus that has finally used the toner cartridge  224 . 
     The toner cartridge  224  corresponds to the image forming unit  507  illustrated in  FIG. 1 , which includes the residual quantity detection sensor capable of detecting the residual quantity of toner particles and the information holding unit capable of holding individual information, which are disposed at predetermined portions. In the present exemplary embodiment, the information holding unit is the memory tag  225 , which is a contactless IC memory.  FIG. 4  illustrates a memory structure of the memory tag  225 . The memory tag  225  stores a serial number M 10  that is unique to the toner cartridge  224 . Further, the memory tag  225  stores a printed page count value M 11  that represents the use record value, a beginning-of-use date and time M 12  (i.e., an example of the reference date and time), and a device serial number M 13  that is identification information about a finally used apparatus (i.e., a currently using printer body). The cartridge management unit  310  generates cartridge information  311 , as a single record, for each toner cartridge  224  and stores the generated information in the device built-in memory  204 . 
       FIG. 5  is a block diagram illustrating an example of the cartridge information  311  recorded in the device built-in memory  204 . The cartridge information  311  includes a serial number M 20  of each toner cartridge, a printed page count value M 21 , a beginning-of-use date and time M 22 , and a device serial number M 23 , as a single record. Each record further includes cartridge size (e.g., normal or large capacity), finally used date and time (i.e., another example of the reference date and time), residual quantity, and cartridge type (e.g., reused). The printed page count value and the residual quantity include values measured at the beginning-of-use date and time and values measured at the latest use date and time. 
     The cartridge information  311  recorded in the nonvolatile memory can be browsed and printed at any time. For example, it is feasible to print and confirm the cartridge information  311  about the toner cartridge  224  having been presently and previously used in response to a print instruction received via the operation panel  221 .  FIG. 6  illustrates a printed example of the cartridge information  311 . The cartridge information  311  can be displayed on a screen of the connected host computer  100 . 
     The cartridge information  311  can be updated (or rewritten) at any time based on the information recorded in the memory tag  225 . For example, the printed page count value M 21  included in the cartridge information  311  recorded in the device built-in memory  204  can be rewritten into a changed value in synchronization with a change of the printed page count value M 11  (i.e., use record value). 
       FIG. 7  is a flowchart illustrating a procedure of printed page counter update processing performed by the cartridge management unit  310 . The cartridge management unit  310  waits until the printing of one page using the toner cartridge  224  completes (NO in step S 11 ). If the printing completes (YES in step S 11 ), then in step S 12 , the cartridge management unit  310  updates the printed page count value M 11  of the memory tag  225 . Subsequently, in step S 13 , the cartridge management unit  310  writes the updated printed page count value M 11  of the memory tag  225  into the device built-in memory  204  as the printed page count value M 22 . According to the above-mentioned processing, respective printed page count values M 11  and M 21  are constantly the same unless the cartridge  224  is changed to another one. However, it is not always necessary to perform the printed page counter update processing for each page. For example, the cartridge management unit  310  performs the printed page count value update processing for every five pages, or for each print job. 
     The toner cartridge  224  has a replacement detection function as described in detail below. One of objects of the present exemplary embodiment is surely detecting an actual replacement of toner cartridge even in a case where the memory tag  225  of a replaced toner cartridge is a copied one and identical to that of a corresponding genuine toner cartridge. In this case, it is necessary to accurately manage the use record value and the replacement history regardless of the genuineness of the toner cartridge  224 . However, in actual scenes, there is a case where the toner cartridge  224  is temporarily installed and used in another printer body and subsequently returned to the original printer body. Therefore, in the present exemplary embodiment, the image forming apparatus compares information recorded in the memory tag  225  with information stored in the device built-in memory  204  and, if a difference between two pieces of information (i.e., two pieces of individual information) exceeds a predetermined range, the image forming apparatus determines that the currently using toner cartridge  224  is a replaced one. Then, the image forming apparatus adds cartridge information read from the toner cartridge  224 , as new cartridge information  311 , to the device built-in memory  204 . 
     The replacement detection function can be realized by the controller  210 .  FIG. 8  is a flowchart illustrating an example procedure of replacement detection processing that can be performed by the controller  210 . In step S 21 , the controller  210  checks whether the present state is immediately after power supply ON of the printer  200 . If the controller  210  determines that the present state is not immediately after power supply ON of the printer  200  (No in step S 21 ), then in step S 22 , the controller  210  checks whether the present state is immediately after sleep restoration. If the controller  210  determines that the present state is not immediately after sleep restoration (NO in step S 22 ), then in step  23 , the controller  210  checks whether a cartridge replacement door has been opened or closed. If the controller  210  determines that the cartridge replacement door has been neither opened nor closed (NO in step S 23 ), the operation returns to step S 21 . The above-mentioned processing in steps S 21  to S 23  means that the controller  210  is functionally operable as a detection unit configured to detect a state where there is a possibility that the toner cartridge  224  has been replaced. If the confirmation result in any one of steps S 21 , S 22 , and S 23  is “YES” (YES in step S 21 , S 22 , or S 23 ), the controller  210  determines that the printer  200  is currently in an operational state identified in step S 21 , S 22 , or S 23 . Then, the controller  210  compares the information recorded in the memory tag  225  with the information stored in the device built-in memory  204 . Further, the controller  210  determines whether the difference between two pieces of information (i.e., two pieces of individual information) exceeds the predetermined range. 
     As an example, in step S 24 , the controller  210  reads the serial number M 10  recorded in the memory tag  225  via the cartridge management unit  310 . Further, in step S 25 , the controller  210  reads the serial number M 20  stored in the device built-in memory  204 . Then, in step S 26 , the controller  210  compares the read serial numbers M 10  and M 20 . If the compared serial numbers coincide with each other (YES in step S 26 ), then in step S 27 , the controller  210  reads the printed page count value M 11  (i.e., the use record value) from the memory tag  225 . Further, in step S 28 , the controller  210  reads the printed page count value M 21  from the device built-in memory  204 . Then, in step S 29 , the controller  210  compares the read printed page count values M 11  and M 21 . If the compared printed page count values coincide with each other (YES in step S 29 ), the controller  210  determines that the currently using toner cartridge  224  is not a replaced one because the difference is within the predetermined range, and then the operation returns to step S 21 . 
     If the serial numbers M 10  and M 20  do not coincide with each other (NO in step S 26 ), or if the printed page count values M 11  and M 21  do not coincide with each other (NO in step S 29 ), then in step S 210 , the controller  210  determines that the currently using toner cartridge  224  is a replaced one because the difference exceeds the predetermined range. In this case, in step S 211 , the controller  210  adds a new record to the cartridge information in the device built-in memory  204  and starts managing the replaced cartridge as a new cartridge (i.e., new individual information). Further, in step S 212 , the controller  210  overwrites and updates the serial number and the printed page count value stored in the device built-in memory  204  with the information read from the memory tag  225 . Then, the operation returns to step S 21 . 
     As mentioned above, a significant amount of shift will occur in the printed page count value, if the toner cartridge  224  is temporarily installed and used in another printer body and subsequently returned to the original printer body. In this case, it may be erroneously determined that the toner cartridge has been replaced. Therefore, when the printed page count value recorded in the memory tag  225  is less than the printed page count value stored in the device built-in memory  204 , the controller  210  can determine that the difference has exceeded the predetermined range. 
     As mentioned above, in the first exemplary embodiment, the image forming apparatus can detect a replacement of toner cartridge based on the comparison performed for checking the coincidence in printed page count value, more specifically, checking if the difference exceeds the predetermined range, even if the serial numbers of the compared cartridges are identical. More specifically, even in a case where a memory tag attached by a toner cartridge recycled product provider is a copy of a genuine memory tag of a brand-new cartridge (i.e., serial numbers are identical), the image forming apparatus can accurately detect the replaced cartridge and can accurately update the use record value and the replacement history. Further, if any possible cartridge replacement state (e.g., power supply ON, sleep restoration, or cartridge replacement door opening/closure) is detected, the image forming apparatus automatically launches the replacement detection function. Therefore, it is feasible to prevent the image forming apparatus from malfunctioning due to replacement of the toner cartridge  224 . 
     Next, a second exemplary embodiment of the present invention will be described in detail below. In the second exemplary embodiment, the image forming apparatus compares two pieces of beginning-of-use date and time obtained from different toner cartridges. The image forming apparatus according to the present exemplary embodiment has a hardware configuration and a functional configuration similar to those described in the first exemplary embodiment. The image forming apparatus according to the present exemplary embodiment is different from the image forming apparatus described in the first exemplary embodiment in the contents of replacement detection processing to be performed by the cartridge management unit  310 .  FIG. 9  is a flowchart illustrating an example procedure of the replacement detection processing according to the present exemplary embodiment. Processing to be performed in steps S 31  to S 36  is similar to the processing performed in steps S 21  to S 26  illustrated in  FIG. 8  and therefore redundant description thereof will be avoided. 
     If it is determined that the serial number read from the memory tag  225  coincides with the serial number read from the device built-in memory  204  (YES in step S 36 ), then in step S 37 , the cartridge management unit  310  reads the beginning-of-use date and time from the memory tag  225 . Further, in step S 38 , the cartridge management unit  310  reads the beginning-of-use date and time from the device built-in memory  204 . Then, in step S 39 , the cartridge management unit  310  compares the two pieces of beginning-of-use date and time having been read. If it is determined that the two pieces of beginning-of-use date and time coincide with each other (YES in step S 39 ), the cartridge management unit  310  determines that the toner cartridge  224  has not been replaced (remains the same), and the operation returns to step S 31 . If it is determined that the two pieces of beginning-of-use date and time do not coincide with each other (NO in step S 39 ), then in step S 310 , the cartridge management unit  310  determines that the toner cartridge  224  is a replaced one because the difference exceeds the predetermined range. In this case, similar to the first exemplary embodiment, in step S 311 , the cartridge management unit  310  adds a new record to the cartridge information in the device built-in memory  204  and starts managing the replaced cartridge as a new cartridge history. Further, in step S 312 , the cartridge management unit  310  overwrites and updates the serial number and the beginning-of-use date and time stored in the device built-in memory  204  with the information read from the memory tag  225 . Then, the operation returns to step S 31 . 
     As mentioned above, in the second exemplary embodiment, the image forming apparatus can detect a replacement of toner cartridge based on the comparison performed for checking the coincidence in beginning-of-use date and time even if the serial numbers of the compared cartridges are identical. 
     Next, a third exemplary embodiment of the present invention will be described in detail below. In the third exemplary embodiment, the image forming apparatus compares device serial numbers of currently using apparatuses. The image forming apparatus according to the present exemplary embodiment has a hardware configuration and a functional configuration similar to those described in the first exemplary embodiment. The image forming apparatus according to the third exemplary embodiment is different from the image forming apparatus described in the first exemplary embodiment in the contents of replacement detection processing to be performed by the cartridge management unit  310 .  FIG. 10  is a flowchart illustrating an example procedure of the replacement detection processing according to the present exemplary embodiment. Processing to be performed in steps S 41  to S 46  is similar to the processing performed in steps S 21  to S 26  illustrated in  FIG. 8 . Therefore, redundant description thereof will be avoided. 
     If the serial number read from the memory tag  225  coincides with the serial number read from the device built-in memory  204  (YES in step S 46 ), then in step S 47 , the cartridge management unit  310  reads the device serial number of the currently using printer body from the memory tag  225 . Further, in step S 48 , the cartridge management unit  310  reads the device serial number of the printer body from the device built-in memory  204 . Then, in step S 49 , the cartridge management unit  310  compares the read device serial numbers. If the compared device serial numbers coincide with each other (YES in step S 49 ), the cartridge management unit  310  determines that the toner cartridge  224  has not been replaced (remains the same). Then, the operation returns to step S 41 . If the compared device serial numbers do not coincide with each other (NO in step S 49 ), then in step S 410 , the cartridge management unit  310  determines that the toner cartridge is a replaced one because the difference exceeds the predetermined range. In this case, in step S 411 , similar to the first exemplary embodiment, the cartridge management unit  310  adds a new record to the cartridge information in the device built-in memory  204  and starts managing the replaced cartridge as a new cartridge history. Further, in step S 412 , the cartridge management unit  310  overwrites and updates the serial number stored in the device built-in memory  204  with the information read from the memory tag  225 . Then, in step S 413 , the cartridge management unit  310  rewrites the device serial number in the memory tag  225 . Then, the operation returns to step S 41 . 
     As mentioned above, in the third exemplary embodiment, the image forming apparatus can detect a replacement of toner cartridge based on the comparison performed for checking the coincidence in device serial number of the printer body even if the serial numbers of the compared cartridges are identical. 
     Next, a fourth exemplary embodiment of the present invention will be described in detail below. In the fourth exemplary embodiment, the image forming apparatus compares two pieces of life alarm history information. The life alarm history information is warning history information (irreversible information) about residual life span of the cartridge to be recorded in the cartridge when the toner cartridge residual quantity observed by the printing mechanism unit  220  becomes less than a predetermined value. The life alarm history information can be set beforehand via a setting unit (not illustrated). The life alarm history information is, for example, “FULL state” indicating that the residual quantity is very great, “LOW state” indicating that the residual quantity is very small, or “OUT state” indicating that the residual quantity is zero. Each brand-new cartridge is in the “FULL state.” The state changes from the “FULL state” to the “LOW state” and then to “OUT state” successively with increasing consumed toner amount. The life alarm history information is irreversible information discriminable from history information that can be obtained through simple residual quantity detection, in that the state does not change when the cartridge is refilled with toner particles. 
     The image forming apparatus according to the present exemplary embodiment has a hardware configuration and a functional configuration similar to those described in the first exemplary embodiment. The image forming apparatus according to the present exemplary embodiment is different from the image forming apparatus described in the first exemplary embodiment in the above-mentioned setting unit (not illustrated) and in the replacement detection processing to be performed by the cartridge management unit  310 .  FIG. 11  is a flowchart illustrating a procedure of replacement detection processing according to the present exemplary embodiment. Processing in steps S 51  to S 56  is similar to the processing performed in steps S 21  to S 26  illustrated in  FIG. 8 . Therefore, redundant description thereof will be avoided. 
     If it is determined that the serial number read from the memory tag  225  coincides with the serial number read from the device built-in memory  204  (YES in step S 56 ), then in step S 57 , the cartridge management unit  310  reads the life alarm history information from the memory tag  225 . Further, in step S 58 , the cartridge management unit  310  reads the life alarm history information from the device built-in memory  204 . Then, in step S 59 , the cartridge management unit  310  compares the two pieces of life alarm history information. If the two pieces of life alarm history information coincide with each other (YES in step S 59 ), the cartridge management unit  310  determines that the toner cartridge  224  has not been replaced (remains the same). Then, the operation returns to step S 51 . If the two pieces of life alarm history information do not coincide with each other (NO in step S 59 ), then in step S 510 , the cartridge management unit  310  determines that the toner cartridge is a replaced one because the difference exceeds the predetermined range. Then, in step S 511 , similar to the first exemplary embodiment, the cartridge management unit  310  adds a new record to the cartridge information in the device built-in memory  204  and starts managing the replaced cartridge as a new cartridge history. Further, in step S 512 , the cartridge management unit  310  overwrites and updates the life alarm history information stored in the device built-in memory  204  with the information read from the memory tag  225 . In step S 513 , the cartridge management unit  310  rewrites the device serial number in the memory tag  225 . Then, the operation returns to step S 51 . 
     The determination in step S 59 , i.e., the processing for determining coincidence in the life alarm history information, is not limited to a case where coincidence is strictly required in details. For example, it is feasible to set an appropriate margin in the coincidence determination considering an error in the residual toner quantity detection to be referred to in cartridge life determination, as described in detail below with reference to  FIG. 12 . When the above-mentioned residual quantity detection sensor is used to observe the residual toner quantity, it is uncertain whether the residual toner quantity of the cartridge is observed as being in the “FULL state” or observed as being in the “LOW state” if the detected value is on a borderline. Similarly, it is uncertain whether the residual toner quantity of the cartridge is observed as being in the “LOW state” or observed as being in the “OUT state” if the detected value is on another borderline. The above-mentioned uncertainty is dependent on the performance of the residual quantity detection sensor or the flow of consumed toner particles outgoing from the toner cartridge. In general, it is very difficult to eliminate such an observation error completely. 
     Therefore, it is useful to set an appropriate margin in the coincidence determination when the fact that the life alarm history information never returns to the “FULL state” once it changes into the “LOW state” or the “OUT state” is taken into consideration, regardless of any change in the residual toner quantity. More specifically, in a case where the life alarm history information stored in the main body built-in memory  204  is “FULL state” and the life alarm history information read from the memory tag  225  is “LOW state” or “OUT state”, it can be determined that the cartridge remains the same. Further, in a case where the life alarm history information stored in the main body built-in memory  204  is “LOW state” and the life alarm history information read from the memory tag  225  is “OUT state”, it can be determined that the cartridge remains the same. 
     On the other hand, there is a case where the toner warning information read from the memory tag  225  is determined as “FULL state” even though the life alarm history information stored in the main body built-in memory  204  is “LOW state.” Such a phenomenon never occurs if the cartridge remains the same. Therefore, it can be determined that the currently using cartridge is a replaced one. Similarly, in a case where the toner warning information read from the memory tag  225  is determined as “FULL state” or “LOW state” even though the life alarm history information stored in the main body built-in memory  204  is “OUT state”, it can be determined that the currently using cartridge is a replaced one. 
     As mentioned above, according to the fourth exemplary embodiment, the image forming apparatus can identify a replacement of toner cartridge based on the comparison performed for checking the coincidence in life alarm history information even if the serial numbers of the compared cartridges are identical. 
     OTHER EMBODIMENTS 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2015-181586, filed Sep. 15, 2015, which is hereby incorporated by reference herein in its entirety.