Abstract:
A replaceable component life tracking method and system for multi-operating mode systems having replaceable components with variable wear rates that depend on the system operating mode. The method tracks system use and replaceable component life using a common predetermined parameter, and uses a different predetermined replaceable component wear rate, when necessary, for each replaceable component for each operating mode. The predetermined wear rate for each replaceable component in each operating mode is factored into the accumulated use of each replaceable component in each operating mode before computing the overall accumulated life of each replaceable component.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to the maintenance of systems with replaceable components, and more particularly, to maintenance of systems with replaceable components that have more than one operating mode with different wear rates in different operating modes.  
       BACKGROUND OF THE INVENTION  
       [0002]     Many systems have multiple components that wear at different rates and are replaced as they wear out in order to keep the whole system operating. In such systems the replacement of some or all worn out components may require specially trained service professionals such as field service engineers. Some systems may be designed with replaceable components that are replaceable by the system operator, thereby eliminating or, at least reducing the frequency of, the need to place a service call. This not only may reduce overall maintenance costs, but also reduces system down time by eliminating response time. In either case, replacement by a service call or by the operator, it is desirable to track the usage of replaceable components so as to accurately anticipate when they will fail. U.S. Pat. No. 6,718,285 issued to Schwartz, et al., henceforth referred to as the Schwartz patent, discloses a replaceable component life tracking system and is hereby incorporated in this application by reference.  
         [0003]     The Schwartz patent discloses a replaceable component life tracking system in which all replaceable components are fully operational during system operation, the system operation being tracked by a predetermined parameter. Each replaceable component may have a different expected life span in terms of the predetermined parameter, but they each wear at the same rate toward the end of their expected life span during system operation. The Schwartz replaceable component life tracking system is applicable to many systems. However systems exist which have more than one system operating mode, and in addition have replaceable components that have different operating modes, with different wear rates in the different operating modes. For example, in such a system, a given replaceable component may be fully operating in one system operating mode, but may run in an idle mode in a different system operating mode. In the idle mode the given replaceable component may only be partially operating, and therefore still wearing, but at a lower rate than in the fully operating mode. Further, there may be system operating modes in which a given replaceable component may not be running at all and therefore not wearing. Tracking the life of replaceable components in such multi-mode systems is a more daunting problem than for those single mode systems with single mode replaceable components.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention provides a replaceable component life tracking method and system for multi-operating mode systems having replaceable components with variable wear rates that depend upon the system operating mode. The method of the present invention tracks system use and replaceable component life using a common predetermined parameter, but uses a different predetermined replaceable component wear rate, when necessary, for each replaceable component for each operating mode. The predetermined wear rate for each replaceable component in each operating mode is factored into the accumulated use of each replaceable component in each operating mode before computing the overall accumulated life of each replaceable component.  
         [0005]     The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiment presented below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is an illustration of a system having a digital printer and a user interface that is a preferred embodiment of the invention;  
         [0007]      FIG. 2  is an illustration of the digital printer of  FIG. 1  with the cabinetry removed showing a number of operator replaceable components;  
         [0008]      FIG. 3  is a basic high-level flowchart of a method of replaceable component life tracking in a printing system having just a single four color operating mode;  
         [0009]      FIG. 4  is a basic high-level flowchart for life tracking of idled replaceable components in the method of the present invention; and  
         [0010]      FIG. 5  is a block diagram of the software components in the Main Machine Controller that controls the digital printer of  FIG. 1  in an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]      FIG. 1  is an illustration of a system  100  according to the preferred embodiment of the present invention, and includes a digital printer  103  and a Digital Front End (DFE) controller  104 . Digital printer  103  is provided with Operator Replaceable Component (ORC) devices that enable a typical operator to perform the majority of maintenance on the system without requiring the services of a field engineer. The ORC devices in the preferred embodiment are those components within systems that become worn after periods of use. Specifically, the ORC devices are those components used within digital printing systems that wear with use. These ORC devices within the preferred embodiment have predictable lifetimes that can be anticipated by parameters relative to the use of the digital printer  103 . Therefore, it is possible to anticipate when these ORC devices will need to be replaced before the wear on them results in less than desirable performance in the system  100 . Digital printer  103 , in the preferred embodiment, is a NexPress® 2100 digital color on demand printing press, however, the present invention pertains to systems in general and digital printing systems in particular.  
         [0012]     DFE controller  104  located adjacent to the printer  103 , and includes a computational element  105  that interfaces with a database management system within the DFE controller  104 , and a Graphical User Interface (GUI)  106  that communicates with computational element  105 . In the preferred embodiment, GUI  106  on the DFE controller  104  provides the operator with the ability to view the current status of ORC devices in the digital printer  103 , and to thus perform maintenance in response to maintenance information provided on the graphical display on GUI  106 , as well as to view various alerts that are provided from the DFE controller  104 . It should be understood that while the preferred embodiment details a system  100  with a digital printer  103  having at least one computational element and another computational element associated with DFE controller  106 , similar systems can be provided with more computational elements or fewer computational elements, and that these variations will be obvious to those skilled in the art. In general, virtually any interactive device can function as DFE controller  104 , and specifically any Graphics User Interface (GUI)  106  can function in association with DFE controller  104  as employed by the present invention.  
         [0013]     The database management system within the DFE controller  104  will receive data that details the usage of each of the ORC devices based on the number of prints made, the types of paper being used, the color composition of the printed pages as well as various sensor inputs. The database management system then takes the received data and creates a life tracking system that keeps track of the remaining life of the ORC devices and informs the operator of remaining life via the GUI  106 . The preferred embodiment employs tables displayed on the GUI  106  to inform the operators to the current status of the ORC devices. However, it should be noted that numerous variations are possible including, but not limited to, direct messages related to a single ORC device, various types of alarms, or even graphical messages on the GUI  106 . The database management system will also prompt the operator when any of the ORC devices need to be replaced. The digital printing system  100  of the present invention provides tracking of the ORC devices in an ORC tracking table along with an automated transmission of the ORC Tracking Table to the GUI  106 . The preferred embodiment of the present invention uses page count and parameters related to customer usage to create the ORC tracking chart. When an operator replaces an ORC, the life counter for that ORC is reset.  
         [0014]     Referring now to  FIG. 2  of the accompanying drawings, a portion of the inside of digital printer  103  is illustrated, showing the image forming reproduction apparatus according to the preferred embodiment of the present invention, designated generally by the numeral  200 . The reproduction apparatus  200  is in the form of an electrophotographic reproduction apparatus and more particularly a color reproduction apparatus wherein color separation images are formed respectively in each of four color modules, and transferred in register to a receiver member as a receiver member is moved through the apparatus while supported on a paper transport web (PTW)  216 . The apparatus  200  illustrates the image forming areas for a digital printer  103  having four color modules, although the present invention is applicable to printers of all types, including printers that print with more or less than four colors.  
         [0015]     The elements in  FIG. 2  that are similar from module to module have similar reference numerals with a suffix of B, C, M and Y referring to the color module with which the element is associated; i.e., black, cyan, magenta and yellow, respectively. Each module ( 291 B,  291 C,  291 M,  291 Y) is of similar construction. PTW  216 , which may be in the form of an endless belt, operates in association with all the modules  291 B,  291 C,  291 M,  291 Y, and a receiver member is transported by PTW  216  from module to module. Four receiver members, or sheets,  212   a, b, c  and  d  are shown simultaneously receiving images from the different modules, it being understood that each receiver member may receive one color image from each module and that in this example up to four color images can be received by each receiver member. The movement of the receiver member with the PTW  216  is such that each color image transferred to the receiver member at the transfer nip of each module is a transfer that is registered with the previous color transfer so that a four-color image formed on the receiver member has the colors in registered superposed relationship on the receiver member. The receiver members are then serially detacked from the PTW  216  and sent to a fusing station (not shown) to fuse or fix the toner images to the receiver member. The PTW  216  is reconditioned for reuse by providing charge to both surfaces using, for example, opposed corona chargers  222 ,  223  which neutralize the charge on the two surfaces of the PTW  216 . These chargers  222 ,  223  are operator replaceable components within the preferred embodiment and have an expected life span after which chargers  222 ,  223  will require replacement.  
         [0016]     Each color module includes a primary image-forming member (PIFM), for example a rotating drum  203 B, C, M and Y, respectively. The drums rotate in the directions shown by the arrows and about their respective axes. Each PIFM rotating drum  203 B, C, M and Y has a photoconductive surface, upon which a pigmented marking particle image is formed. The PIFM rotating drums  203 B, C, M and Y have predictable lifetimes and constitute operator replaceable components. The photoconductive surface for each PIFM  203 B, C, M and Y within the preferred embodiment is actually formed on outer sleeves  265 B, C, M and Y, upon which the pigmented marking particle image is formed. These outer sleeves  265 B, C, M and Y, have lifetimes that are predictable and therefore, are operator replaceable components. In order to form images, the outer surface of the PIFM is uniformly charged by a primary charger such as a corona charging devices  205 B, C, M and Y, respectively or other suitable charger such as roller chargers, brush chargers, etc. The corona charging devices  205 B, C, M and Y each have a predictable lifetime and are operator replaceable components. The uniformly charged surface is exposed by suitable exposure mechanism  206 B, C. M and Y, such as, for example, a laser, or more preferably an LED or other electro-optical exposure device, or even an optical exposure device, to selectively alter the charge on the surface of the outer sleeves  265 B, C, M and Y, of the PIFM rotating drums  203 B, C, M and Y to create an electrostatic latent image corresponding to an image to be reproduced. The electrostatic image is developed by application of pigmented charged marking particles to the latent image bearing photoconductive drum by a development station  281 B, C, M and Y, respectively. Each of the development stations  281 B, C, M and Y has a particular color of pigmented marking particles associated respectively therewith. Thus, each module creates a series of different color marking particle images on the respective photoconductive drum. The development stations  281 B, C, M and Y, have predictable lifetimes before they require replacement and are operator replaceable components. In lieu of a photoconductive drum, which is preferred, a photoconductive belt can be used.  
         [0017]     Each marking particle image formed on a respective PIFM rotating drum is transferred electrostatically to an intermediate transfer module (ITM)  208 B, C, M and Y, respectively. The ITM  208 B, C, M and Y have an expected lifetime and are, therefore, considered to be operator replaceable components. In the preferred embodiment, each ITM  208 B, C, M and Y, has an outer sleeve  243 B, C, M and Y that contains the surface to which the image is transferred from PIFM rotating drums  203 B, C, M and Y. These outer sleeves  243 B, C, M and Y are considered operator replaceable components with predictable lifetimes. The PIFM rotating drums  203 B, C, M and Y are each caused to rotate about their respective axes by frictional engagement with their respective ITM  208 B, C, M and Y. The arrows in the ITMs  208 B, C, M and Y indicate the direction of their rotation. After transfer, the toner image is cleaned from the surface of the photoconductive drum by a suitable cleaning device  204 B, C, M and Y, respectively to prepare the surface for reuse for forming subsequent toner images. Cleaning devices  204 B, C, M and Y are considered operator replaceable components by the present invention.  
         [0018]     Marking particle images are respectively formed on the surfaces  242 B, C, M and Y for each of the outer sleeve  243 B, C, M and Y for ITMs  208 B, C, M and Y. The marking particle images are transferred to a receiving surface of a receiver member, which is fed into a nip between the intermediate image transfer member drum and a transfer backing roller (TBR)  221 B, C, M and Y, respectively. The TBRs  221 B, C, M and Y have predictable lifetimes and are considered to be operator replaceable components by the invention. Each TBR  221 B, C, M and Y, is suitably electrically biased by a constant current power supply  252  to induce the charged toner particle image to electrostatically transfer to a receiver sheet. Although a resistive blanket is preferred for TBR  221 B, C, M and Y, the TBR  221 B, C, M and Y can also be formed from a conductive roller made of aluminum or other metal. The receiver member is fed from a suitable receiver member supply (not shown) and is suitably “tacked” to the PTW  216 . The receiver member moves serially into each of the nips  210 B, C, M and Y where it receives the respective marking particle image in a suitable registered relationship to form a composite multicolor image. As is well known, the colored pigments can overlie one another to form areas of colors different from that of the pigments.  
         [0019]     The receiver member exits the last nip and is transported by a suitable transport mechanism (not shown) to a fuser where the marking particle image is fixed to the receiver member by application of heat and/or pressure. A detack charger  224  may be provided to deposit a neutralizing charge on the receiver member to facilitate separation of the receiver member from the PTW  216 . The detack charger  224  is another component that is considered to be an operator replaceable component within the scope of this invention. The receiver member with the fixed marking particle image is then transported to a remote location for operator retrieval. The respective ITMs  208 B, C, M and Y are each cleaned by a respective cleaning device  211 B, C, M and Y to prepare it for reuse. Cleaning devices  211 B, C, M and Y are considered by the invention to be operator replaceable components having lifetimes that can be predicted.  
         [0020]     Appropriate sensors (not shown) of any well known type, such as mechanical, electrical, or optical sensors for example, are utilized in the reproduction apparatus  200  to provide control signals for the apparatus. Such sensors are located along the receiver member travel path between the receiver member supply through the various nips to the fuser. Further sensors may be associated with the primary image forming member photoconductive drum, the intermediate image transfer member drum, the transfer backing member, and various image processing stations. As such, the sensors detect the location of a receiver member in its travel path, and the position of the primary image forming member photoconductive drum in relation to the image forming processing stations, and respectively produce appropriate signals indicative thereof. Such signals are fed as input information to a microprocessor based logic and control unit LCU which has an associated computational element. Based on such signals and a suitable program for the microprocessor, the control unit LCU produces signals to control the timing operation of the various electrostatographic process stations for carrying out the reproduction process and to control, for example, drive by motor M for various drums and belts. The production of a program for a number of commercially available microprocessors, which are suitable for use with the invention, is a conventional skill well understood in the art. The particular details of any such program would, of course, depend on the architecture of the designated microprocessor.  
         [0021]     The receiver members utilized with the reproduction apparatus  200  can vary substantially. For example, they can be thin or thick paper stock (coated or uncoated) or transparency stock. As the thickness and/or resistivity of the receiver member stock varies, the resulting change in impedance affects the electric field used in the nips  210 B, C, M, Y to urge transfer of the marking particles to the receiver members. Moreover, a variation in relative humidity will vary the conductivity of a paper receiver member, which also affects the impedance and hence changes the transfer field. Such humidity variations can affect the expected lifetime of operator replaceable components.  
         [0022]     In feeding a receiver member onto PTW  216 , charge may be provided on the receiver member by charger  226  to electrostatically attract the receiver member and “tack” it to the PTW  216 . A blade  227  associated with the charger  226  may be provided to press the receiver member onto the belt and remove any air entrained between the receiver member and the PTW. The PTW  216 , the charger  226  and the blade  227  are considered operator replaceable components.  
         [0023]     The endless transport web (PTW)  216  is entrained about a plurality of support members. For example, as shown in  FIG. 2 , the plurality of support members are rollers  213 ,  214  with preferably roller  213  being driven as shown by motor M to drive the PTW. Support structures  275   a, b, c, d  and e are provided before entrance and after exit locations of each transfer nip to engage the PTW  216  on the backside and alter the straight line path of the PTW to provide for wrap about each respective ITM. This wrap allows for a reduced pre-nip ionization and for a post-nip ionization which is controlled by the post-nip wrap. The nip is where the pressure roller contacts the backside of the PTW or, where no pressure roller is used, where the electrical field is substantially applied. However, the image transfer region of the nip is a smaller region than the total wrap. Pressure applied by the transfer backing rollers (TBRs)  221 B, C, M and Y is upon the backside of the belt  216  and forces the surface of the compliant ITM to conform to the contour of the receiver member during transfer. The TBRs  221 B, C, M and Y may be replaced by corona chargers, biased blades or biased brushes, each of which would be considered by this invention to be operator replaceable components. Substantial pressure is provided in the transfer nip to realize the benefits of the compliant intermediate transfer member which are a conformation of the toned image to the receiver member and image content on both a microscopic and macroscopic scale. The pressure may be supplied solely by the transfer biasing mechanism or additional pressure applied by another member such as a roller, shoe, blade or brush, all of which are operator replaceable components according to the present invention.  
         [0024]     Four color printing, such as in the embodiment illustrated in  FIG. 2 , is most common. Typically such four color printing devices operate in a single mode, which prints black, cyan, magenta, and yellow images in register on receiver sheets to form combinations of text and pictorial images. During printing in this single mode, all replaceable components for all color modules are fully operating. The Schwartz patent, disclosed above, discloses a replaceable component life tracking system in such a printing system in which all replaceable components are fully operational during system operation, the system operation being tracked by the number of four color pages printed. Each replaceable component may have a different expected life span in terms of the number of four color pages printed, but they each wear at the same rate toward the end of their expected life span during system operation.  
         [0025]     Printing systems, such as in the embodiment illustrated in  FIG. 2 , can be designed to operate in modes other than four color printing as described above. For example, such a system could have a black-only printing mode or a spot color printing mode that uses only one or two of the color modules. In such system operating modes one or more of the color modules,  291 B, C, M, and Y in  FIG. 2  will by running in an idle mode and the replaceable components associated with those idling modules may be wearing at a lower rate than in the fully operational mode or perhaps not wearing at all. In addition to the possible alternate operating modes described above for the printing system illustrated in  FIG. 2 , such a printing system could be designed with additional imaging modules for printing specialty colors in addition to black, cyan, magenta, and yellow. Examples of uses for additional printing modules are: 1) printing pictorial images with color marking particles in addition to cyan, magenta, and yellow to increase the color gamut attainable with just those three subtractive primary color marking particles; 2) printing with marking particles specially formulated to match a desired spot color such as a company logo; 3) printing with clear colorless marking particles to provide a protective or gloss enhancing overcoat for the colored image, or to reduce the relief appearance of some marking particle images. Such printing systems with more than four printing modules would obviously have multiple printing modes, including four color printing. In some of those printing modes one or more modules would be running in an idle mode and the replaceable components associated with those idling modules may be wearing at a lower rate than in the fully operational mode or perhaps not wearing at all.  
         [0026]     One embodiment of the present invention is used in a printing system as illustrated in  FIG. 2  but with a fifth printing module in addition to  291 B, C, M, and Y, such fifth printing module capable of being used for any of the above described uses. Such fifth module, not shown, would include the same components as modules  291 B, C, M, and Y, that is, an image forming member  203  with photoconductor coated outer sleeve  265 , a primary charging device  205 , exposure mechanism  206 , a development station  281 , an intermediate transfer member  208  with outer sleeve  243 , cleaning devices  204  and  211 , and a transfer backing roller  221 . Several development stations  281  might be available for use in a fifth printing module to accommodate the use of different color marking particles in different printing runs without having to change the marking particle developer in the developer station for each printing run.  
         [0027]     The replaceable component life tracking method for the printing system illustrated in  FIG. 2  with no fifth module and only one four color printing mode treats all replaceable components as though they are all running and depleting their useful life as documents are printed.  FIG. 3  is a basic high-level flowchart of this method. As sheets are printed and delivered to the output destination, they are identified as a “sheet complete”  20  which results in a corresponding Machine Sheet Counter (MSC)  22  being advanced. These MSCs  22 , which are advanced when sheets are printed, are used as the base from which the amount of wear of the replaceable component is tracked and thus are used to determined the remaining life of the operator replaceable components. Each operator replaceable component has a set of Installed Sheet Counters (ISC)  24  associated therewith. When an operator replaceable component is installed, the ISCs  24  are loaded with the MSC  22  values at the time of replacement. This establishes a reference from where the remaining life of the respective operator replaceable components is derived as prints are being generated and the MSCs  22  are advancing. Each operator replaceable component also has a life expectancy or Custom Life (CL)  26  value associated therewith for the calculation of the operator replaceable component&#39;s remaining life. This CL  26  value is specific to each operator replaceable component and is derived from the life history of replacements for that specific operator replaceable component. The final remaining life calculation  28  is determined by first normalizing the MSC and ISC to a single equivalent base sheet size count, EMSC and EISC, and then subtracting this from the custom life of the replaceable component.  
         [0028]     The operator replaceable component life tracking method of the present invention takes into account the idle mode running of some of the replaceable components in a printing system such as illustrated in  FIG. 2 , when such a system is operated in modes other than four color as described above.  FIG. 4  is a basic high-level flowchart for life tracking of idled replaceable components according to the method of the present invention. The method of the present invention utilizes three new tracking components for each operator replaceable component: 1) an idle control (ICR)  32  parameter used to configure the replaceable component as an idle-able component; 2) an idle counter (ICT)  30  parameter used to keep track of the number of equivalent base sheet size counts while the replaceable component is idled; and 3) an idle wear factor (IWF)  34  parameter used to calculate a new ICT  30  value as sheets are being printed. As sheets are being printed, the sheet complete information  20  is sent to the replaceable component tracking system where the information is used by an Idle Control Logic (ICL)  36  functionality. The ICL  36  will determine which replaceable components are idled and appropriately advance each idled components ICT  30  based on the sheet complete information and the components IWF  34 .  
         [0029]     As indicated above, some components, such as a development station, my be idled by removing it from the machine, which may result in a “zero wear” factor. However, some replaceable components, my be idle but are left in the machine. For example, a fifth module image forming member  203  my not be in use, thus it is being idled, however it still may be rotating or is exposed to various gases and chemical vapors, and thus has a non-zero wear factor resulting in some wear while being idled. A remaining life calculation  38  according to the method of the present invention is now determined by first normalizing the machine sheet counters (MSC)  22  and installed sheet counters (ISC)  24  to a single equivalent base sheet size counts, EMSC and EISC, as in the single four color mode method, then subtracting this from the custom life (CL) 26  of the replaceable component, and lastly adding in the ICT  30  value for the replaceable component. This now takes into account the idle time use of the replaceable component and prevents premature replacements.  
         [0030]      FIG. 5  is a block diagram of the software components in the Main Machine Controller (MMC)  300  that controls the digital printer  103  of  FIG. 1  in which the above embodiment of the present invention is used. MMC  300  controls the printing process of digital printer  103  which is illustrated in  FIG. 2 , and communicates with the Digital Front End (DFE)  104  of  FIG. 1 .  
         [0031]     The RC Manager  302  is responsible for maintaining replaceable component (RC) data, tracking remaining life of the RCs, and sending exception events to the DFE  104  and operator to indicate when RCs need replacement/attention. RC data includes, but is not limited to: enabled status, expiration status, expiration type, last replacement date, last replacement sheet counter data, idle count, idle control, and replacement history data for prior replacements. The RC Manager  302  stores this data to the MMC Hard Disk Drive (HDD)  310  when replacements, configuration changes, or updates are made.  
         [0032]     The Statistics Controller  304  is responsible for maintaining the various sheet counters/meters for sheets that have been printed for the life of the machine. When sheets are printed/delivered to the output source, the Statistics Controller  304  is notified via a Sheet Complete Event Message and this triggers the Statistics Controller  304  to update the sheets counters accordingly. The Statistics Controller  304  also in turn sends this data to the RC Manager  302  for the purpose of updating the RC idle counters for those RC that are being idled. The Statistics Controller  304  also stores the sheet counters in NVRAM where they are made available to the RC Manager  302  as well as preserving the data.  
         [0033]     The MMC Mode Controller  306  is responsible for the proper cycling-up of the digital printer  103  in the desired 4-color or 5-color mode. The MMC Mode Controller  306  sends this information to the RC Manager  302  which indicates if a printing module ( 291 B, C, M, Y, or a fifth module in  FIG. 2 ) has been fully cycled-up or is cycled-up into an idle mode. The Mode Controller  306  determines how to cycle-up the 5th module (can be extended to other modules as well) based on the DFE press policy and by development station status information send to the MMC from the printing modules.  
         [0034]     The foregoing discussion has described the preferred embodiment of the present invention, but variations will be readily apparent to those of ordinary skill in the art, and therefore the scope of the invention should be measured by the appended claims.