Patent Publication Number: US-8543015-B2

Title: Replacement toner cartridge management apparatus, replacement toner cartridge management system, image forming apparatus, replacement toner cartridge management method, and recording medium

Description:
This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2010-162323 filed on Jul. 16, 2010, the entire disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a replacement toner cartridge management apparatus that determines the right time to output an instruction to deliver a replacement toner cartridge when there is a need to replace a toner cartridge loaded on an image forming apparatus; a replacement toner cartridge management system employing the replacement toner cartridge management apparatus; an image forming apparatus employed in the replacement toner cartridge management system; a replacement toner cartridge management method; a recording medium having a replacement toner cartridge management program stored thereon to make a computer of the replacement toner cartridge management apparatus implement the replacement toner cartridge management method; and a recording medium having a replacement toner cartridge management program stored thereon to make a computer of the image forming apparatus implement the replacement toner cartridge management method. 
     2. Description of the Related Art 
     The following description sets forth the inventor&#39;s knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art. 
     Conventionally, if the remaining consumable resource in a consumable unit loaded on an image forming apparatus such as a digital photo copier, a digital photo printer, or a multifunctional machine called MFP (Multi Function Peripheral), for example, the remaining toner in a toner cartridge is lower than a predetermined level, the image forming apparatus determines that the toner cartridge nearly runs out of toner (the toner cartridge is in toner near empty state) and displays for the user a message stating that the toner cartridge nearly runs out of toner, on a display panel provided thereon. Noticing this message, the user prepares a replacement toner cartridge, or places an order for a replacement toner cartridge if not having any ones in stock. 
     Meanwhile, in recent years, an image forming apparatus connected with a management apparatus to exchange information with has been more commonly used in a remote management system (for example, Japanese Unexamined Patent Publication No. 2002-297969). In many cases, a retailer of image forming apparatuses or a provider of office supplies have their own management apparatus in their own place, in order to collect, store, and manage for their business, various types of information including toner near empty information from a plurality of image forming apparatuses in their users&#39; places. Being connected with the image forming apparatuses, the management apparatus is capable of recognizing that the toner cartridges nearly run out toner and that these are replaced with new ones. 
     In some cases, the management apparatus is further connected with an order receiving apparatus receiving orders for a replacement toner cartridge (for example, Japanese Unexamined Patent Publication No. 2008-271231). In such a case, the management apparatus further transmits an order to the order receiving apparatus, so that a replacement toner cartridge will be delivered to the user. In other words, this is exactly a system to automatically deliver a replacement toner cartridge to users while they need not bother to place an order for it. 
     Such an automatic order and delivery system is very useful if the manufacturer and the user are in an agreement about billing and payment for the use of an image forming apparatus. In accordance with such an agreement, the user pay a service fee for making one copy, which includes a charge for the toner used for the copy. That is, it is convenient for the user to pay a service fee simply depending on the number of copies regardless of how many replacement toner cartridges they ordered and have a replacement toner cartridge automatically delivered without the need for placing an order for it. At the same time, the manufacturer can expect a benefit from saving the costs of handling order transactions. 
     With such a system in which a management apparatus automatically places an order for a replacement toner cartridge, it is preferred that a toner cartridge containing as little remaining toner as possible is replaced with a new one, in terms of cost-effectiveness. 
     However, a delivery instruction is conventionally outputted when a toner cartridge, regardless of the amount of toner remaining in it, is replaced with a new one, which causes a toner wasting problem. 
     And such a problem cannot be resolved using the technologies disclosed in the Japanese Unexamined Patent Publications No. 2002-297969 and No. 2008-271231. 
     The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, a replacement toner cartridge management apparatus is provided with: 
     a receiver which receives toner cartridge replacement information indicating a toner cartridge loaded on an image forming apparatus which the replacement toner cartridge management apparatus can access via a communication circuit, has been replaced with a new one; 
     an information obtainer which obtains remaining toner information of the toner cartridge removed from the image forming apparatus, when the toner cartridge replacement information is received by the receiver; 
     a time determiner which, if the remaining toner information obtained by the information obtainer indicates a value smaller than a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the remaining toner information indicates a value larger than or equal to a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     a transmitter which outputs a delivery instruction according to the determination made by the time determiner. 
     According to a second aspect of the present invention, a replacement toner cartridge management system is provided with an image forming apparatus having one or more than one toner cartridge loaded thereon and a management apparatus which can access each other via a communication circuit, wherein: 
     the image forming apparatus is provided with a transmitter which transmits toner cartridge replacement information indicating that one of the toner cartridges has been replaced with a new one, and 
     the management apparatus is provided with:
         a receiver which receives the toner cartridge replacement information;   an information obtainer which obtains remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received by the receiver;   a time determiner which, if the remaining toner information obtained by the information obtainer indicates a value smaller than a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the remaining toner information indicates a value larger than or equal to a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and   a transmitter which outputs a delivery instruction at the time determined by the time determiner.       

     According to a third aspect of the present invention, an image forming apparatus is provided with: 
     a receiver which receives toner cartridge replacement information indicating that a toner cartridge loaded on the image forming apparatus or a different image forming apparatus which the image forming apparatus can access via a communication circuit has been replaced with a new one; 
     an information obtainer which obtains remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received by the receiver; 
     a time determiner which, if the remaining toner information obtained by the information obtainer indicates a value smaller than a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the remaining toner information indicates a value larger than or equal to a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     a transmitter which outputs a delivery instruction at the time determined by the time determiner. 
     According to a fourth aspect of the present invention, a replacement toner cartridge management method for a system provided with an image forming apparatus having one or more than one toner cartridge loaded thereon and a management apparatus which can access each other via a communication circuit, comprising: 
     the image forming apparatus&#39;s transmitting toner cartridge replacement information indicating one of the toner cartridges has been replaced with a new one, and 
     the management apparatus&#39;s:
         receiving the toner cartridge replacement information;   obtaining remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received;   if the obtained remaining toner information indicates a value smaller than a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the obtained remaining toner information indicates a value larger than or equal to a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and   outputting a delivery instruction according to the determination.       

     According to a fifth aspect of the present invention, a non-transitory computer-readable recording medium having a replacement toner cartridge management program stored thereon to make a computer of a management apparatus execute: 
     receiving toner cartridge replacement information indicating a toner cartridge loaded on an image forming apparatus which the management apparatus can access via a communication circuit has been replaced with a new one; 
     obtaining remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received; 
     if the obtained remaining toner information indicates a value smaller than a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the obtained remaining toner information indicates a value larger than or equal to a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     outputting a delivery instruction according to the determination. 
     According to a sixth aspect of the present invention, a non-transitory computer-readable recording medium having a replacement toner cartridge management program stored thereon to make a computer of an image forming apparatus execute: 
     receiving toner cartridge replacement information indicating a toner cartridge loaded on the image forming apparatus or a different image forming apparatus which the image forming apparatus can access via a communication circuit has been replaced with a new one; 
     obtaining remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received; 
     if the obtained remaining toner information indicates a value smaller than a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the obtained remaining toner information indicates a value larger than or equal to a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     outputting a delivery instruction according to the determination. 
     The above and/or other aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The preferred embodiments of the present invention are shown by way of example, and not limitation, in the accompanying figures, in which: 
         FIG. 1  is a view illustrating a configuration of a replacement toner cartridge management system according to one mode of implementing the present invention; 
         FIG. 2  is a view schematically illustrating a configuration of an image forming apparatus employed in the replacement toner cartridge management system of  FIG. 1 ; 
         FIG. 3  is a view to explain the image forming apparatus&#39;s machinery to feed toner in a sub-hopper from a toner cartridge; 
         FIG. 4  is a view to explain the image forming apparatus&#39;s machinery to feed toner in a development device from the sub-hopper; 
         FIG. 5  is a view schematically illustrating a configuration of a machinery to measure toner concentration; 
         FIG. 6  is a block diagram illustrating a configuration of a controller of the image forming apparatus of  FIG. 2 ; 
         FIG. 7  is a block diagram illustrating a configuration of a replacement toner cartridge management apparatus; 
         FIG. 8  is a flowchart representing a processing routine to detect a toner empty state; 
         FIG. 9  is a view to explain an example of an alert message displayed on an operation panel of the image forming apparatus; 
         FIG. 10  is a table illustrating the statuses depending on remaining toner level; 
         FIG. 11  is a view to explain the overview of a procedure executed by a replacement toner cartridge management system according to one mode of embodied implementation to determine the right time to output an instruction to deliver a replacement toner cartridge and output such an instruction; 
         FIG. 12  is another view to explain the overview of a procedure executed by a replacement toner cartridge management system according to one mode of embodied implementation to determine the right time to output an instruction to deliver a replacement toner cartridge and output such an instruction; 
         FIG. 13  is yet another view to explain the overview of a procedure executed by a replacement toner cartridge management system according to one mode of embodied implementation to determine the right time to output an instruction to deliver a replacement toner cartridge and output such an instruction; 
         FIG. 14  is a view to explain some cases in which the right time to output an instruction to deliver a replacement toner cartridge is determined; 
         FIG. 15  is a table to determine the right time to output an instruction to deliver a replacement toner cartridge depending on the conditions; and 
         FIG. 16  is a flowchart representing a processing routine executed by the management server to determine the right time to output an instruction to deliver a replacement toner cartridge, which starts when an image forming apparatus detects replacement of a toner cartridges loaded thereon. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following paragraphs, some preferred embodiments of the invention will be described by way of example and not limitation. It should be understood based on this disclosure that various other modifications can be made by those in the art based on these illustrated embodiments. 
     Hereinafter, one mode of implementing the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is a view schematically illustrating a configuration of a replacement toner cartridge management system according to one mode of implementing the present invention. 
     As illustrated in  FIG. 1 , this management system is basically provided with one or more than one image forming apparatus  51  and a management server  50 , which are connected to each other via a communication circuit such as Internet. The management server  50  is further connected to an order receiving server  52  via the Internet or the like. 
     The management server  50  is ordinarily provided in a service center or the like taking care of the image forming apparatuses  51  to manage information of the image forming apparatuses  51  by user accounts. More specifically, by communicating with the image forming apparatuses  51 , the management server  50  monitors the remaining toner level(s) of a single toner cartridge or plural toner cartridges containing one color or different colors of toner that is a consumable resource, loaded on each of the image forming apparatuses  51 , and if there is a replacement toner cartridge(s) for the toner cartridge(s) in stock. That will be further described in detail later. The image management server  50  further manages billing transactions and maintenance issues by collecting billing information such as number of prints and trouble information from the image forming apparatuses  51 . 
     Users may use different types of image forming apparatuses; the image forming apparatuses  51  may be of different types. For example, the image forming apparatuses  51  may be printers, full-color copiers, monochrome copiers, and the like. Therefore, the image forming apparatuses  51  may load four toner cartridges containing four colors of toner: yellow (Y), magenta (M), cyan (C), and black (K), or only one toner cartridge containing one color of toner, black (K). 
     Furthermore, by monitoring unique uses and use patterns of the users, the management server  50  remotely controls the image forming apparatuses  51  for perfect performance based on settings and the like of the image forming apparatuses  51  stored on its own recording medium. The setting information of the image forming apparatuses  51  is integrally managed by the management server  50 ; it therefore can be changed by the management server  50  quite easily even if some of the image forming apparatuses  51  are located in remote areas. 
     The image forming apparatuses  51  and the management server  50  exchange information with each other, for example by e-mails via the Internet network. 
     Being further connected to the order receiving server  52 , the management server  50  transmits an order for a replacement toner cartridge to the order receiving server  52  according to information indicating a need of toner cartridge replacement received from the image forming apparatuses  51 , so that the order receiving server  52  can arrange for an automatic delivery. 
       FIG. 2  is a view schematically illustrating a configuration of the image forming apparatus  51 . In this example, a tandem color printer is employed as the image forming apparatus  51 . 
     As illustrated in  FIG. 1 , the image forming apparatus  51  has a paper feeder  200  in the lower area of the body  51 A, a color image former  100  in the middle area of the body  51 A, and a paper discharger  600  in the upper area of the body  51 A, respectively. A paper conveyance path  206  conveying toward the upper area, paper (a sheet of paper) S provided by the paper feeder  200  is extended all the way from the paper feeder  200  to the paper discharger  600 . 
     The color image former  100  includes: a driving roller  40  and a driven roller  50  provided in the middle area of the vertical direction of the body  51 A; a midway transfer belt  30  horizontally going around a group of the driving roller  40  and the driven roller  50  to run toward the direction indicated by arrow; and image forming units  10 Y,  10 M,  10 C, and  10 K containing yellow (Y), magenta (M), cyan (C), and black (K) of toner, respectively, provided along the belt&#39;s running direction. 
     Toner images formed by the image forming units  10 Y,  10 M,  10 C, and  10 K are layered together and transferred onto the transfer belt  30 . In the second transfer process, the merged toner images are further transferred on the paper S passing trough the corner of the transfer belt  30  (on the extreme right of the body) via the paper conveyance path  206 ; the sheet S is conveyed to a fuser  300  to have the merged toner images fixed thereon. 
     The image forming units  10 Y,  10 M,  10 C, and  10 K forming images by the electrostatic copy method is provided with: a charger; a print head  21  including four laser diodes, a polygon mirror, a scanner lens, and the like; an exposure unit  20  including four reflection mirrors  22  and the like; development devices  9 Y,  9 M,  9 C, and  9 K; photoreceptor drums  11 Y,  11 M,  11 C, and  11 K; a transfer portion; and the like, which are all located in the vicinity of the image forming units themselves. 
     Above the image forming units  10 Y,  10 M,  10 C, and  10 K, toner cartridges  70 Y,  70 M,  70 C, and  70 K and sub-hoppers  80 Y,  80 M,  80 C, and  80 K are provided as supplier machineries that feed toner in the development devices  9 Y,  9 M,  9 C, and  9 K of the image forming units  10 Y,  10 M,  10 C, and  10 K, respectively. 
     The toner cartridges  70 Y,  70 M,  70 C, and  70 K are removably loaded on the body  51 A so as to be replaced with new ones when need. The toner cartridges  70 Y,  70 M,  70 C, and  70 K have a fuse attached thereto but not illustrated in this drawing; the body  51 A detects an unused state of the toner cartridges when their fuses are conductive, and releases the unused state when the fuses are cut out. In other words, cutting the fuses, replacement of the toner cartridges is recognized. 
     In  FIG. 1 , a portion with the number  400  is a communicator communicating with external machines, and a portion with the number  500  is an operation panel provided with a set of keys and a display. 
       FIG. 3  is a view to explain a machinery to feed toner in the sub-hoppers  80 Y,  80 M,  80 C, and  80 K from the toner cartridges  70 Y,  70 M,  70 C, and  70 K, respectively. 
     As illustrated in  FIG. 3 , when the toner cartridges  70 Y,  70 M,  70 C, and  70 K are loaded on the body  51 A, the sub-hoppers  80 Y,  80 M,  80 C, and  80 K open shutters on their top to receive toner from the toner cartridges  70 Y,  70 M,  70 C, and  70 K. 
     The toner cartridge  70 Y,  70 M,  70 C, and  70 K have a spiral spring  71  inside, and feed toner in the sub-hoppers  80 Y,  80 M,  80 C, and  80 K, respectively, by having their spiral springs  71  rotated by stepper motors (also referred to as cartridge motors)  72 . 
     There provided two stepper motors  72  for the four spiral springs  71 ; one of the two works for the toner cartridges  70 Y and  70 M, and the other one works for the toner cartridges  70 C and  70 K. An even number of gears  73  are arranged between an inlet valve of the toner cartridges  70 Y and  70 C and an inlet valve for the toner cartridges  70 K and  70 M; when the stepper motors  72  perform normal rotation, the spiral springs  71  of the toner cartridges  70 Y and  70 C are properly rotated while the spiral springs  71  of the toner cartridges  70 K and  70 M are rotated idle, and when the stepper motors  72  perform reverse rotation, the spiral springs  71  of the toner cartridges  70 Y and  70 C are rotated idle while the spiral springs  71  of the toner cartridges  70 K and  70 M are properly rotated. Switching the stepper motors  72  between normal rotation and reverse rotation determines whether or not to allow the toner cartridges  70 Y,  70 M,  70 C, and  70 K to feed toner. 
       FIG. 4  is a view to explain a machinery to feed toner in the development devices  9 Y,  9 M,  9 C, and  9 K from the sub-hoppers  80 Y,  80 M,  80 C, and  80 K. 
     As illustrated in  FIG. 4 , there provided one stepper motor (also referred to as sub-hopper motor)  81  for each of the sub-hoppers, the sub-hoppers  80 Y,  80 M,  80 C, and  81 K. 
     The sub-hoppers  80 Y,  80 M,  80 C, and  80 K feed toner in the development devices  9 Y,  9 M,  9 C, and  9 K, respectively, by having paddles  82  and spiral rollers  83  inside of themselves rotated by the sub-hopper motors  81 . The remaining toner levels of the sub-hoppers  80 Y,  80 M,  80 C, and  80 K are detected by a toner empty sensor (piezoelectric sensor)  84 . 
       FIG. 5  is a view schematically illustrating a configuration of a machinery to measure toner concentration. 
     As illustrated in  FIG. 5 , the development devices  9 Y,  9 M,  9 C, and  9 K is filled with developing agent (toner and carrier); the developing agent in the development devices  9 Y,  9 M,  9 C, and  9 K is stirred by a Mylar plastic fin  92  attached to a motor-driven screw agitator  91 . While the developing agent in the periphery of a toner concentration sensor  93  provided on the bottom of the development devices  9 Y,  9 M,  9 C, and  9 K is stirred by the Mylar plastic fin  92 , new developing agent is let in the periphery of the toner concentration sensor  93 . In other words, the developing agent in the periphery of the toner concentration sensor  93  is replaced with new one every other turn (ripple) of the screw agitator  91 . 
     The toner concentration sensor  93  is a TCR sensor (magnetic sensor), for example. The toner concentration sensor  93  measures the toner concentration of the developing agent by reading out the magnetic permeability of iron included in the carrier of a unit volume of the developing agent in the periphery of the toner concentration sensor  93 . That is, the higher a converted value (10-bit resolution) of an analog signal read out by the toner concentration sensor  93  is, the lower the toner concentration is. 
       FIG. 6  is a block diagram illustrating a configuration of a controller of the image forming apparatus  51 . 
     As illustrated in  FIG. 6 , the controller includes a CPU  401 , a communication interface (I/F)  402 , an image processor  403 , an image memory  404 , a laser diode driver  405 , an operation panel  500 , a recording medium  700 , a ROM  406 , a RAM  407 , and an engine controller  408 , as primary members. 
     The CPU  401  integrally controls all operations of the image forming apparatus  51 . Also, the CPU  401  reads out a necessary program from the ROM  406 ; converts image data by the image processor  403 ; and writes and reads image data in and out from the image memory  404 . Furthermore, the CPU  401  contributes to smooth printing operation by nicely arranging the times of a series of sequential operations of the color image former  100 , the paper feeder  200 , and the like. Furthermore, based on various information inputted from the engine controller  408 , the CPU  401  detects a toner near empty state and an empty state of the toner cartridge  70 Y,  70 M,  70 C, and  70 K; detects the remaining toner level of a replaced toner cartridge; detects the condition due to toner consumption data (print volume, ratio Black to White, and the like); and displays a predetermined message about the time for replacing the toner cartridges  70 Y,  70 M,  70 C, and  70 K, on the operation panel  500 . 
     The communication I/F  402  serves to connect the image forming apparatus  51  to a LAN such as a LAN card or a LAN board, and externally receives data to be printed out according to a print job and transfers it to the image processor  403 . 
     Also, the communication I/F  402  transmits toner empty information, alert information, trouble information, and information of various printing events to the management server  50  managing the image forming apparatus  51  (see  FIG. 13 ) via the Internet, and receives data and an instruction from the administration server  50 . 
     Receiving data to be printed out according to a print job from the communication I/F  402 , the image processor  403  converts the data into Y, M, C, and K image data objects for color reproduction and outputs the image data objects to the image memory  404  to have them stored thereon. 
     Reading out Y, M, C, and K image data objects from the image memory  404 , the laser diode driver  405  drives the laser diodes of the exposure unit  20 . 
     The operation panel  500  allows users to perform entry operations and displays various messages for them. 
     The recording medium  700  stores print log data, toner cartridge replacement log data, and the like, as well as various other data and applications. 
     The ROM  406  stores programs to control image forming operation and other data such as a table serving for toner supply control, toner empty detection control, and other controls. 
     The RAM  407  serves as a work area for the CPU  402 . 
     Receiving signals and state information from the toner empty sensor  84 , the TCR sensor  93 , a toner cartridge loading sensor (not illustrated in the drawing), a TC door sensor (not illustrated), a front cover (not illustrated), the cartridge motors  72 , the sub-hopper motors (not illustrated), and the like, the engine controller  408  controls printing operation. 
       FIG. 7  is a block diagram illustrating a configuration of the management server  50  employed in the replacement toner cartridge management system of  FIG. 1 . 
     The management server  50  is provided with a CPU  50   a , a ROM  50   b , a RAM  50   c , a display  50   e , an entry portion  50   f , a network interface card (NIC)  50   g , and the like, which are connected to each other via a system bus  50   h.    
     The CPU  50   a  integrally controls the entire management server  50  by executing programs stored on the ROM  50   b . Specifically, in this mode of embodied implementation, the CPU  50   a  receives and manages information of remaining toner that is a consumable resource remaining in the toner cartridges  70 Y,  70 M,  70 C, and  70 K loaded on the image forming apparatuses  51 ; and information indicating that the toner cartridges  70 Y,  70 M,  70 C, and  70 K have been replaced. Also, the CPU  50   a  updates the information when the need arises. Receiving toner cartridge replacement information indicating that the toner cartridge  70 Y,  70 M,  70 C, or  70 K loaded on an image forming apparatus  51  has been replaced with a new one, the CPU  50   a  obtains the remaining toner level of the removed toner cartridge or the toner consumption data (print volume, average value of the ratio, Black/White) from the image forming apparatus  51 ; determines a right time to output an instruction to deliver a replacement toner cartridge; and outputs a delivery instruction at the right time. 
     The ROM  50   b  is a recording medium that stores programs and data for the CPU  50   a  to execute processing. 
     The ROM  50   c  is a recording medium that provides a work area for the CPU  50   a  to execute processing according to an operation program. 
     The recording medium  50   d  is, for example, a hard disk drive, and stores various data, applications, and the like. Specifically, in this mode of embodied implementation, the recording medium  50   d  stores remaining toner information of the toner cartridges  70 Y,  70 M,  70 C, and  70 K loaded on the image forming apparatus  51 , which is rewritable thereon. Furthermore, the recording medium  50   d  stores information such as the locations of the image forming apparatuses  51  which correspond to the delivery addresses to which replacement toner cartridges and other replacement consumable units such as replacement transfer belt unit, replacement fuser units, and replacement developing units will be delivered. 
     The display  50   e  is, for example, a CRT display or a liquid-crystal display, and displays various messages, entry accepting screens, selection screens, and other screens for administrator-level users and other users. 
     The entry portion  50   f  serves for administrator-level users and other users to perform entry operation, and includes a keyboard, a mouse, and the like. 
     The network interface card  50   g  serves as a communicator that exchanges data with the image forming apparatuses  51  and the order receiving server  52  via the Internet network. 
       FIG. 8  is a flowchart representing a processing routine to detect a toner empty state, executed by the image forming apparatuses  51 . 
     In  FIG. 8 , the remaining toner levels of the toner cartridges  70 Y,  70 M,  70 C, and  70 K slowly go down with feeding of toner; the toner cartridges  70 Y,  70 M,  70 C, and  70 K eventually run out of toner (become in toner empty state). 
     There are the four states depending on remaining toner level: “normal” (Step S 1 ), “toner near empty (alert)” (Step S 2 ), “toner empty (permit printing)” (Step S 3 ), and “toner empty (prohibit printing)” (Step S 4 ). 
     Unlike “toner near empty (alert)” (Step S 2 ), “toner empty (permit printing)” (Step S 3 ), and “toner empty (prohibit printing)” (Step S 3 ), “normal” (Step S 1 ) means that the toner cartridges  70 Y,  70 M,  70 C, and  70 K and the sub-hoppers  80 Y,  80 M,  80 C, and  80 K are sufficiently filled with toner. In these four states including the state of “normal” (Step S 1 ), the CPU  401  accumulates the rotation quantum numbers of the cartridge motors  72 , and estimates the amount of toner fed in the sub-hoppers  80 Y,  80 M,  80 C, and  80 K based on the rotation quantum numbers. 
     The CPU  401  determines the state as “toner near empty (alert)” (Step S 2 ) if estimating that the toner cartridges  70 Y,  70 M,  70 C, and  70 K nearly run out of toner based on the estimated amount of toner fed in the sub-hoppers  80 Y,  80 M,  80 C, and  80 K. In the state of “toner near empty (alert)”, as illustrated in  FIG. 9 , an alert message stating that toner will run out in a short time is displayed on the operation panel  500  so that users will be encouraged to prepare a replacement toner cartridge. After that, thousands of prints still can be made using the toner cartridges  70 Y,  70 M,  70 C and  70 K before “toner empty (prohibit printing)” is detected, users therefore have enough time to prepare a replacement toner cartridge even when need to place an order because of no replacement toner cartridges in stock. 
     The CPU  401  determines the state as “toner empty (permit printing)” (Step S 3 ) when the toner empty sensor  84  has repeatedly detected a toner empty state of the sub-hoppers  80 Y,  80 M,  80 C, and  80 K as many as a predetermined number of times. In this state, the toner cartridges  70 Y,  70 M,  70 C, and  70 K have no toner left inside while the sub-hoppers  80 Y,  80 M,  80 C, and  80 K still contain toner for as many as 100 prints approximately, and printing is therefore permitted. 
     The CPU  401  determines the state as “toner empty (prohibit printing)” (Step S 4 ) when the sub-hoppers  80 Y,  80 M,  80 C, and  80 K run out of toner by further consuming it for a predetermined number of prints after “toner empty (permit printing)” is detected. In this state, printing is prohibited. 
     In the state of “toner near empty (alert)” (Step S 2 ) and “toner empty (permit printing)” (Step S 3 ), as illustrated in  FIG. 9 , an alert message is displayed on the operation panel  500  to let the user know that the toner will run out soon. In the state of “toner empty (prohibit printing)” (Step S 4 ), a strong alert message is displayed on the operation panel  500  to let the user know that the toner has run out, and printing is prohibited. 
     These states depending on remaining toner level: normal, toner near empty, toner empty (permit printing), and toner empty (prohibit printing) (described in Steps S 1  to S 4 , respectively) are incorporated in a table illustrated in  FIG. 10 . 
     As is obviously understood from the table of  FIG. 10 , when the state turns to “toner empty (permit printing)” (Step S 3 ), it is acceptable to replace the toner cartridges  70 Y,  70 M,  70 C, and  70 K since these contain little remaining toner (almost run out of toner); when the state turns to “toner near empty” (Step S 2 ), it is not preferred to replace the toner cartridges  70 Y,  70 M,  70 C, and  70 K since these still contain some remaining toner. 
       FIGS. 11 ,  12 , and  13  are views to explain examples of a procedure executed by a replacement toner cartridge management system according to one mode of embodied implementation to determine the right time to output an instruction to deliver a replacement toner cartridge and output such an instruction, in which different delivery instructions are outputted. 
     In the mode of embodied implementation illustrated in  FIGS. 11 ,  12 , and  13 , the management server  50  determines the right time to output an instruction to deliver a replacement toner cartridge, based on remaining toner information of a toner cartridge to be replaced, paper volume (also referred to as PV), and average value (also referred to as coverage) of the ratio, black (B)/white (W) which are received form an image forming apparatus  51 . 
       FIG. 11  illustrates an example of a procedure to determine that a delivery instruction should be outputted when a toner cartridge is replaced with a new one, which starts when a toner cartridge in toner empty (permit printing) state or toner empty (prohibit printing) state, i.e. containing little remaining toner is replaced with a new one. 
     Initially, a toner cartridge loaded on an image forming apparatus  51  is replaced (circled number  1 ). Then the image forming apparatus  51  transmits information indicating a toner cartridge has been replaced with a new one, to the management server  50  connected therewith via a communication circuit (circled number  2 ). 
     As is previously mentioned, replacement of the toner cartridges is recognized when their attached fuses are cut out. When having its fuse conductive, the image forming apparatus  51  detects the cartridge detection signal as “new toner cartridge”; when having the fuse cut out, it detects the cartridge detection signal as “old toner cartridge”. 
     Receiving the toner cartridge replacement information from the image forming apparatus  51 , the management server  50  returns thereto an inquiry for remaining toner information of the toner cartridge having been replaced (also referred to as remaining toner information of the removed toner cartridge), the PV, and the coverage (circled number  3 ). 
     And the image forming apparatus  51  accordingly returns the remaining toner information of the removed toner cartridge, the PV, and the coverage (circled number  4 ). 
     Based on the information received from the image forming apparatus  51 , the management server  50  determines the right time to output an instruction to deliver a replacement toner cartridge, and records the determined time (circled number  5 ). 
     A delivery instruction will be outputted according to the determination. In this example of  FIG. 11 , the management server  50  determines that a delivery instruction should be outputted when the toner cartridge is replaced with a new one, and therefore outputs a delivery instruction immediately after the determination (circled number  6 ). 
       FIG. 12  illustrates an example of a procedure to determine that a delivery instruction should be outputted when a toner cartridge becomes nearly empty, e.g. eventually when the new toner cartridge most recently loaded becomes near empty, if the PV and the coverage are smaller than their second predetermined values that are smaller than their first predetermined values, which starts when a toner cartridge in toner near empty state or normal state (normal toner condition) prior to toner near empty state, i.e. still containing some remaining toner is replaced with a new one. 
     The operations with the circled numbers  1  to  5  are the same as described with reference to  FIG. 11 . In this example of  FIG. 12 , the management server  50  determines that a delivery instruction should be outputted when a toner cartridge becomes nearly empty, e.g. eventually when the new toner cartridge most recently loaded becomes nearly empty, and therefore requests the image forming apparatus  51  to return a notification when the new toner cartridge most recently loaded thereon becomes nearly empty (circled number  7 ). And receiving from the image forming apparatus  51  a notification of the nearly empty toner cartridge (circled number  8 ), the management server  50  outputs an instruction to deliver a replacement toner cartridge (circled number  9 ). 
       FIG. 13  illustrates an example of a procedure to determine that a delivery instruction should be outputted when a predetermined period of time has elapsed after a toner cartridge is replaced with a new one, if the PV and the coverage are smaller than their first predetermined values but either of them is larger than or equal to their second predetermined values, which starts when a toner cartridge in toner near empty state or normal state prior to toner near empty state, i.e. still containing some remaining toner is replaced with a new one. 
     In this example, the management server  50  requests the image forming apparatus  51  to return a notification when a predetermined period of time has elapsed after the toner cartridge is replaced (circled number  10 ). And receiving from the image forming apparatus  51  a notification indicating that a predetermined period of time has elapsed after then (circled number  11 ), the management server  50  outputs an instruction to deliver a replacement toner cartridge (circled number  12 ). 
       FIG. 14  is a view to explain some cases in which the right time to output an instruction to deliver a replacement toner cartridge is determined. Each of the cases is started with the management server  50 &#39;s outputting a delivery instruction when a toner cartridge is replaced with a new one (when the management server  50  receives information indicating that a toner cartridge has been replaced with a new one). In this mode of embodied implementation: a first predetermined value for PV is 500 printed pages per day; a second predetermined value for PV is 100 printed pages per day; a first predetermined value for coverage is 75%; and a second predetermined value for coverage is 25%, and a predetermined period of time required for printing 500 pages needs to elapse since the toner cartridge is replaced. 
     When a toner cartridge in toner near empty state or normal state is replaced with a new one, i.e. a toner cartridge still containing some remaining toner is replaced with a new one, the management server  50  determines that a delivery instruction should be outputted when another toner cartridge becomes nearly empty, which will meet the object of saving toner and the requirement of users who wish to have as least replacement toner cartridges in stock as possible. Meanwhile, when a toner cartridge in toner empty state (permit printing or prohibit printing) is replaced with a new one, the management server  50  determines that a delivery instruction should be outputted now, right after the replacement of a toner cartridge as usual. 
     Some practical cases of this mode of embodied implementation hereinafter will be described. 
     [Case—1] 
     In Case 1, receiving toner cartridge replacement information from an image forming apparatus  51 , the management server  50  returns thereto an inquiry for remaining toner information, the PV, and the coverage, then receives them all; the received remaining toner information is toner empty (permit printing) or toner empty (prohibit printing), for example. 
     Further in this case, the user of the image forming apparatus  51  replaces a toner cartridge with a new one when it is in toner empty state, i.e. when it contains little remaining toner. On the basis of the facts, the management server  50  recognizes that the user wishes to have a replacement toner cartridge as soon as possible, before the printing is prohibited due to toner empty (prohibit printing). And it is preferred to replace a toner cartridge containing little remaining toner with a new one, and the management server  50  therefore determines that a delivery instruction should be outputted when a toner cartridge is replaced with a new one (when receiving the toner cartridge replacement information) as indicated by circled number  1  of  FIG. 14 , regardless of the PV and the coverage received from the image forming apparatus  51 . 
     [Case—2] 
     In Case 2, receiving toner cartridge replacement information from an image forming apparatus  51 , the management server  50  returns thereto an inquiry for remaining toner information, the PV, and the coverage, then receives them all; the received remaining toner information is toner near empty or normal, for example. 
     Further in this case, the user of the image forming apparatus  51  replaces a toner cartridge with a new one when it is in toner near empty state or normal state, i.e. when it still contains some remaining toner. On the basis of the facts that the PV is smaller than its second predetermined value, 100 printed pages per day, and the coverage is smaller than its second predetermined value, 25%, the user possibly wishes to have at least replacement toner cartridges in stock as possible, and if outputting a delivery instruction later to meet the user&#39;s requirement, the low level of toner consumption possibly allows the user to receive a replacement toner cartridge before printing is prohibited due to toner empty (prohibit printing). However, it is not preferred to replace a toner cartridge still contains some remaining toner with a new one, and the management server  50  therefore determines that a delivery instruction should be outputted when a toner cartridge becomes nearly empty (as indicated by circled number  2  of  FIG. 14 ). 
     [Case—3] 
     In Case 3, receiving toner cartridge replacement information from an image forming apparatus  51 , the management server  50  returns thereto an inquiry for remaining toner information, the PV, and the coverage, then receives them all; the received remaining toner information is toner near empty or normal, and the received PV and coverage are larger than or equal to their second predetermined values, for example. 
     In this case, toner will run out more rapidly than in Case 2, since the PV and the coverage are larger than or equal to their second predetermined values. If the management server  50  determines that a delivery instruction should be outputted when a toner cartridge becomes nearly empty as in Case 2, the user possibly fails to receive a replacement toner cartridge before printing is prohibited due to toner empty (prohibit printing). 
     To prevent the inconvenience, even when a toner cartridge in a toner near empty state or normal state is replaced with a new one: the management server  50  determines that a delivery instruction should be outputted when a toner cartridge is replaced with a new one (when receiving toner cartridge replacement information) as indicated by circled number  1  of  FIG. 14 , if the PV is larger than or equal to its first predetermined value, 500 printed pages per day or the coverage is larger than or equal to its first predetermined value, 75%. 
     Alternatively, the management server  50  determines that a delivery instruction should be outputted when a predetermined period of time required for printing 500 pages has elapsed after a toner cartridge is replaced with a new one, if the PV is smaller than its first predetermined value, 500 printed pages per day and the coverage is smaller than its first predetermined value 75%; or if the PV is larger than or equal to its second predetermined value, 100 printed pages per day or the coverage is larger than or equal to its second predetermined value, 25%. 
       FIG. 15  illustrates a table containing the information provided above. In  FIG. 15 , the circle symbol indicates that a delivery instruction should be outputted when a toner cartridges is replaced with a new one (when receiving toner cartridge replacement information); the triangle symbol indicates that a delivery instruction should be outputted when a predetermined period of time has elapsed after a toner cartridge is replaced with a new one; and the x-mark symbol indicates that a delivery instruction should be outputted when a toner cartridge becomes nearly empty. 
     In this mode of embodied implementation, when a toner cartridge in toner near empty state or normal state is replaced with new one: it is determined to output an instruction to deliver a replacement toner cartridge at a right time based on toner consumption data such as the PV and the coverage, so that the user can receive a replacement toner cartridge properly before the new toner cartridge most recently loaded becomes empty. Specifically, when a toner cartridge is replaced with a new one and toner cartridge replacement information is received, a delivery instruction will be outputted immediately if the level of toner consumption is high; a delivery instruction will be outputted after a certain period of time if the level of toner consumption is rather high; and a delivery instruction will be outputted when the new toner cartridge most recently loaded becomes empty, if the level of toner consumption is low. 
     In this way, the user can receive a replacement toner cartridge for the currently loaded toner cartridge nicely right before it becomes empty. This would contribute to eliminating a waste of toner. 
       FIG. 16  is a flowchart representing a processing routine executed by the management server  50  to determine the right time to output an instruction to deliver a replacement toner cartridge, which starts when an image forming apparatus  51  detects replacement of a toner cartridge loaded thereon. The processing routine is executed by the CPU  50   a  of the management server  50  according to an operation program stored on a recording medium such as the ROM  50   b.    
     In Step S 11 , an image forming apparatus  51  detects replacement or the toner near empty state of a toner cartridge loaded thereon, and then in Step S 12 , the image forming apparatus  51  transmits toner cartridge replacement information to the management server  50 . 
     Receiving the toner cartridge replacement information in Step S 15 , the management server  50  returns to the image forming apparatus  51  causing the toner cartridge replacement information, an inquiry for the remaining toner level of the toner cartridge (remaining toner information), the PV, and the coverage, in Step S 16 . 
     Receiving this inquiry from the management server  50  in Step S 13 , the image forming apparatus  51  returns thereto the remaining toner information, the PV, and the coverage in Step S 14 . 
     Receiving the remaining toner information, the PV, and the coverage in Step S 17 , the management server  50  judges whether or not the remaining toner information is toner near empty or normal, i.e. whether or not the toner cartridge still contained some toner when it was replaced with a new one, in Step S 18 . 
     If the remaining toner information is not toner near empty or normal, i.e. if the toner cartridge was in toner near empty state when it was replaced with a new one (NO in Step S 18 ), it is judged that an instruction to deliver a replacement toner cartridge should be outputted when a toner cartridge is replaced with a new one (when receiving toner cartridge replacement information) in Step S 19 . And then, a delivery instruction is outputted in Step S 22 . 
     If the remaining toner information is toner near empty or normal (YES in Step S 18 ), the PV and the coverage are compared to their reference values in Step S 20 . 
     If the PV is larger than or equal to its first predetermined value, 500 printed pages per day or the coverage is larger than or equal to its first predetermined value, 75% (State A in Step S 20 ), it is determined that an instruction to deliver a replacement toner cartridge should be outputted when a toner cartridge is replaced with a new one (when receiving toner cartridge replacement information) in Step S 21 . And then, a delivery instruction is outputted in Step S 22 . 
     In Step S 20 , if the PV is larger than or equal to its second predetermined value, 100 printed pages per day but smaller than its first predetermined value, 500 printed pages per day; or if the coverage is larger than or equal to its second predetermined value 25% but smaller than its first predetermined value, 75% (State B in Step S 20 ), it is determined that an instruction to deliver a replacement toner cartridge should be outputted when 500 pages have been completely printed after a toner cartridge is replaced with a new one (after receiving toner cartridge replacement information) in Step S 23 . And then in Step S 24 , the image forming apparatus  51  is instructed to issue a notification when having completely printed 500 pages after a toner cartridge is replaced with a new one and a delivery instruction is outputted when there is such a notification. 
     In Step S 20 , if the PV is smaller than its second predetermined value, 100 printed pages per day and the coverage is smaller than its second predetermined value, 25% (State C in Step S 20 ), it is determined that an instruction to deliver a replacement toner cartridge should be outputted when a toner cartridge becomes nearly empty in Step S 25 . And then in Step S 26 , a delivery instruction is outputted when a notification of toner near empty is received from the image forming apparatus  51 . 
     The modes of implementing the present invention have been described in the foregoing specification, which does not mean that the present invention shall be construed as limited to the particular forms disclosed. For example, the PV and the coverage are employed as information indicating toner consumption. Alternatively, information obtained by a counter to count the number of printed pages by paper size may be employed. 
     The management server  50  receives toner cartridge replacement information, remaining toner information, the PV, and the coverage; determines the right time to output an instruction to deliver a replacement toner cartridge; and outputs a delivery instruction (outputs an order). Instead of the management server  50 , one image forming apparatus  51  may collectively have all these functions of the management server  50  so as to receive toner cartridge replacement information, remaining toner information, the PV, and the coverage; determine the right time to output an instruction to deliver a replacement toner cartridge; and output a delivery instruction (output an order). In this case, the operations described above are performed according to an operation program by the control of the CPU  401  of the image forming apparatus  51 . 
     Specifically, in these modes of embodied implementation, an order receiving server  52  is employed in the management system, and the management server  50  outputs a delivery instruction to the order receiving server  52 . Alternatively, the management server  50  may display a message encouraging the user to place an order, on its own display  50   e  or a display of another machine such as a personal computer. In such a case, an order placement operation is manually performed. 
     Alternatively, the consumable units may be those dedicated for inkjet image forming apparatuses. 
     Each of the following is one aspect of the present invention of the subject application having been described above: a replacement toner cartridge management apparatus which contributes to eliminating a waste of toner by reducing the amount of toner remaining in a toner cartridge to be replaced with a new one; a replacement toner cartridge management system; an image forming apparatus; a replacement toner cartridge management method; and recording mediums. 
     [1] A replacement toner cartridge management apparatus provided with: 
     a receiver which receives toner cartridge replacement information indicating a toner cartridge loaded on an image forming apparatus which the replacement toner cartridge management apparatus can access via a communication circuit, has been replaced with a new one; 
     an information obtainer which obtains remaining toner information of the toner cartridge removed from the image forming apparatus, when the toner cartridge replacement information is received by the receiver; 
     a time determiner which, if the remaining toner information obtained by the information obtainer indicates a value smaller than a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the remaining toner information indicates a value larger than or equal to a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     a transmitter which outputs a delivery instruction according to the determination made by the time determiner. 
     [2] The replacement toner cartridge management apparatus as recited in the aforementioned item [1], wherein the time determiner determines the right time to output an instruction to deliver a replacement toner cartridge based on the toner consumption data of the image forming apparatus, if the remaining toner information indicates a value larger than or equal to the predetermined value. 
     [3] The replacement toner cartridge management apparatus as recited in the aforementioned item [2], wherein: 
     the toner consumption data is a print volume; and 
     if the print volume is larger than or equal to a first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received; if the print volume is smaller than the first predetermined value and is larger than or equal to a second predetermined value that is smaller than the first predetermine value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when a period of time has elapsed after the receipt of the toner cartridge replacement information; or if the print volume is smaller than the second predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the currently loaded toner cartridge becomes nearly empty. 
     [4] The replacement toner cartridge management apparatus as recited in the aforementioned item [3], wherein: 
     the toner consumption data is an average value of the ratio White to Black; and 
     if the average value of the ratio White to Black is larger than or equal to a first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received; if the average value of the ratio White to Black is smaller than the first predetermined value and is larger than or equal to a second predetermined value that is smaller than the first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when a period of time has elapsed after the receipt of the toner cartridge replacement information; or if the average value of the ratio White to Black is smaller than the second predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the currently loaded toner cartridge becomes nearly empty. 
     [5] The replacement toner cartridge management apparatus recited in the aforementioned item [1], wherein the transmitter outputs a delivery instruction to an order receiving server which the replacement toner cartridge management apparatus can access via the communication circuit. 
     [6] An image forming apparatus provided with: 
     a receiver which receives toner cartridge replacement information indicating that a toner cartridge loaded on the image forming apparatus or a different image forming apparatus which the image forming apparatus can access via a communication circuit has been replaced with a new one; 
     an information obtainer which obtains remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received by the receiver; 
     a time determiner which, if the remaining toner information obtained by the information obtainer indicates a value smaller than a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the remaining toner information indicates a value larger than or equal to a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     a transmitter which outputs a delivery instruction at the time determined by the time determiner. 
     [7] The image forming apparatus as recited in the aforementioned item [6], wherein the time determiner determines the right time to output an instruction to deliver a replacement toner cartridge based on the toner consumption data of the image forming apparatus, if the remaining toner information indicates a value larger than or equal to the predetermined value. 
     [8] The image forming apparatus as recited in the aforementioned item [7], wherein: 
     the toner consumption data is a print volume; and 
     if the print volume is larger than or equal to a first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received; if the print volume is smaller than the first predetermined value and is larger than or equal to a second predetermined value that is smaller than the first predetermine value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when a period of time has elapsed after the receipt of the toner cartridge replacement information; or if the print volume is smaller than the second predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the currently loaded toner cartridge becomes nearly empty. 
     [9] The image forming apparatus as recited in the aforementioned item [7], wherein: 
     the toner consumption data is an average value of the ratio White to Black; and 
     if the average value of the ratio White to Black is larger than or equal to a first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received; if the average value of the ratio White to Black is smaller than the first predetermined value and is larger than or equal to a second predetermined value that is smaller than the first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when a period of time has elapsed after the receipt of the toner cartridge replacement information; or if the average value of the ratio White to Black is smaller than the second predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the currently loaded toner cartridge becomes nearly empty. 
     [10] The image forming apparatus as recited in the aforementioned item [6], wherein the transmitter outputs a delivery instruction to an order receiving server which the replacement toner cartridge management apparatus can access via the communication circuit. 
     [11] A replacement toner cartridge management system provided with an image forming apparatus having one or more than one toner cartridge loaded thereon and a management apparatus which can access each other via a communication circuit, wherein: 
     the image forming apparatus is provided with a transmitter which transmits toner cartridge replacement information indicating that one of the toner cartridges has been replaced with a new one, and 
     the management apparatus is provided with:
         a receiver which receives the toner cartridge replacement information;   an information obtainer which obtains remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received by the receiver;   a time determiner which, if the remaining toner information obtained by the information obtainer indicates a value smaller than a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the remaining toner information indicates a value larger than or equal to a predetermined value, determines that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and   a transmitter which outputs a delivery instruction at the time determined by the time determiner.       

     [12] The replacement toner cartridge management system as recited in the aforementioned item [11], wherein the time determiner determines the right time to output an instruction to deliver a replacement toner cartridge based on the toner consumption data of the image forming apparatus, if the remaining toner information indicates a value larger than or equal to the predetermined value. 
     [13] The replacement toner cartridge management system as recited in the aforementioned item [12], wherein: 
     the toner consumption data is a print volume; and 
     if the print volume is larger than or equal to a first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received; if the print volume is smaller than the first predetermined value and is larger than or equal to a second predetermined value that is smaller than the first predetermine value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when a period of time has elapsed after the receipt of the toner cartridge replacement information; or if the print volume is smaller than the second predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the currently loaded toner cartridge becomes nearly empty. 
     [14] The replacement toner cartridge management system as recited in the aforementioned item [12], wherein: 
     the toner consumption data is an average value of the ratio White to Black; and 
     if the average value of the ratio White to Black is larger than or equal to a first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received; if the average value of the ratio White to Black is smaller than the first predetermined value and is larger than or equal to a second predetermined value that is smaller than the first predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when a period of time has elapsed after the receipt of the toner cartridge replacement information; or if the average value of the ratio White to Black is smaller than the second predetermined value, the time determiner determines that an instruction to deliver a replacement toner cartridge should be outputted when the currently loaded toner cartridge becomes nearly empty. 
     [15] The replacement toner cartridge management system as recited in the aforementioned item [1], wherein the transmitter outputs a delivery instruction to an order receiving server which the replacement toner cartridge management apparatus can access via the communication circuit. 
     [16] A replacement toner cartridge management method for a system provided with an image forming apparatus having one or more than one toner cartridge loaded thereon and a management apparatus which can access each other via a communication circuit, including: 
     the image forming apparatus&#39;s transmitting toner cartridge replacement information indicating one of the toner cartridges has been replaced with a new one, and 
     the management apparatus&#39;s:
         receiving the toner cartridge replacement information;   obtaining remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received;   if the obtained remaining toner information indicates a value smaller than a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the obtained remaining toner information indicates a value larger than or equal to a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and outputting a delivery instruction according to the determination.       

     [17] A non-transitory computer-readable recording medium having a replacement toner cartridge management program stored thereon to make a computer of a management apparatus execute: 
     receiving toner cartridge replacement information indicating a toner cartridge loaded on an image forming apparatus which the management apparatus can access via a communication circuit has been replaced with a new one; 
     obtaining remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received; 
     if the obtained remaining toner information indicates a value smaller than a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the obtained remaining toner information indicates a value larger than or equal to a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     outputting a delivery instruction according to the determination. 
     [18] A non-transitory computer-readable recording medium having a replacement toner cartridge management program stored thereon to make a computer of an image forming apparatus execute: 
     receiving toner cartridge replacement information indicating a toner cartridge loaded on the image forming apparatus or a different image forming apparatus which the image forming apparatus can access via a communication circuit has been replaced with a new one; 
     obtaining remaining toner information of the removed toner cartridge when the toner cartridge replacement information is received; 
     if the obtained remaining toner information indicates a value smaller than a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted when the toner cartridge replacement information is received, or if the obtained remaining toner information indicates a value larger than or equal to a predetermined value, determining that an instruction to deliver a replacement toner cartridge should be outputted at a different time; and 
     outputting a delivery instruction according to the determination. 
     According to the mode as recited in the aforementioned item [1], if the remaining amount of toner contained in the removed toner cartridge is smaller than a predetermined level, it is determined that an instruction to deliver a replacement toner cartridge should be outputted when toner cartridge replacement information is received; if the remaining amount of toner contained in the removed toner cartridge is larger than a predetermined level, it is determined that an instruction to deliver a replacement toner cartridge should be outputted at a different time. And a delivery instruction is outputted according to the determination. 
     Conventionally, an instruction to deliver a replacement toner cartridge is outputted when toner cartridge replacement information is received. On the other hand, if the remaining amount of toner contained in the removed toner cartridge is large, a delivery instruction is outputted at a different time so that the user will receive a replacement toner cartridge nicely when the remaining amount of toner is small. In this way, a waste of toner is eliminated. 
     According to the mode as recited in the aforementioned item [2], if the remaining amount of toner is larger than a predetermined level, the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on the toner consumption data of the image forming apparatus. In this way, the user receives a replacement toner cartridge nicely when the remaining amount of toner is small. 
     According to the mode as recited in the aforementioned item [3], the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on a print volume. 
     According to the mode as recited in the aforementioned item [4], the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on an average value of the ratio White to Black. 
     According to the mode as recited in the aforementioned item [5], an order for a necessary replacement toner cartridge is automatically transmitted to the order receiving server. 
     According to the mode as recited in the aforementioned item [6], if the remaining amount of toner contained in the removed toner cartridge is large, an instruction to deliver a replacement toner cartridge is outputted at a different time so that the user will receive a replacement toner cartridge nicely when the remaining amount of toner is small. By executing such a process, the image forming apparatus contributes to eliminating a waste of toner. 
     According to the mode as recited in the aforementioned item [7], if the remaining amount of toner is larger than a predetermined level, the time to output an instruction to deliver a replacement toner cartridge is determined based on the toner consumption data of the image forming apparatus or a different image forming apparatus. 
     According to the mode as recited in the aforementioned item [8], the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on a print volume. 
     According to the mode as recited in the aforementioned item [9], the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on an average value of the ratio White to Black. 
     According to the mode as recited in the aforementioned item [10], an order for a necessary replacement toner cartridge is automatically transmitted to the order receiving server. 
     According to the mode as recited in the aforementioned item [11], if the remaining amount of toner contained in the removed toner cartridge is large, an instruction to deliver a replacement toner cartridge is outputted at a different time so that the user will receive a replacement toner cartridge nicely when the remaining amount of toner is small. By executing such a process, the replacement toner cartridge management system contributes to eliminating a waste of toner. 
     According to the mode as recited in the aforementioned item [12], if the remaining amount of toner is larger than a predetermined level, the time to output an instruction to deliver a replacement toner cartridge is determined based on the toner consumption data of the image forming apparatus or a different image forming apparatus. 
     According to the mode as recited in the aforementioned item [13], the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on a print volume. 
     According to the mode as recited in the aforementioned item [14], the time to output an instruction to deliver a replacement toner cartridge is determined more accurately, based on an average value of the ratio White to Black. 
     According to the mode as recited in the aforementioned item [15], an order for a necessary replacement toner cartridge is automatically transmitted to the order receiving server. 
     According to the mode as recited in the aforementioned item [16], if the remaining amount of toner contained in the removed toner cartridge is large, a delivery instruction is outputted at a different time so that the user will receive a replacement toner cartridge nicely when the remaining amount of toner is small. In this way, a waste of toner is eliminated. 
     According to the mode as recited in the aforementioned item [17], if the remaining amount of toner contained in the removed toner cartridge is large, a delivery instruction is outputted at a different time so that the user will receive a replacement toner cartridge nicely when the remaining amount of toner is small. By executing such a process, a computer of the replacement toner cartridge management apparatus contributes to eliminating a waste of toner. 
     According to the mode as recited in the aforementioned item [18], if the remaining amount of toner contained in the removed toner cartridge is large, a delivery instruction is outputted at a different time so that the user will receive a replacement toner cartridge nicely when the remaining amount of toner is small. By executing such a process, a computer of the image forming apparatus contributes to eliminating a waste of toner. 
     While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein. 
     While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g. of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably” is non-exclusive and means “preferably, but not limited to”. In this disclosure and during the prosecution of this application, means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present In that limitation: a) “means for” or “step for” is expressly recited; b) a corresponding function is expressly recited; and c) structure, material or acts that support that structure are not recited. In this disclosure and during the prosecution of this application, the terminology “present invention” or “invention” may be used as a reference to one or more aspect within the present disclosure. The language present invention or invention should not be improperly interpreted as an identification of criticality, should not be improperly interpreted as applying across all aspects or embodiments (i.e., it should be understood that the present invention has a number of aspects and embodiments), and should not be improperly interpreted as limiting the scope of the application or claims. In this disclosure and during the prosecution of this application, the terminology “embodiment” can be used to describe any aspect, feature, process or step, any combination thereof, and/or any portion thereof, etc. In some examples, various embodiments may include overlapping features. In this disclosure and during the prosecution of this case, the following abbreviated terminology may be employed: “e.g.” which means “for example”, and “NB” which means “note well”.