Patent Publication Number: US-2021162774-A1

Title: Ratio-based adaptive switching technique

Description:
BACKGROUND 
     Most color-capable laser printers have two modes of operation, a color mode and a monochrome mode. In the color mode, a color cartridge (typically having additive primaries cyan (“C”), magenta (“M”) and yellow (“Y”)) is engaged and available for use along with a monochrome cartridge (typically black or “K”). In monochrome-only (mono or black) mode, the monochrome cartridge is engaged and available for use while the color cartridge is dis-engaged (also termed as “alienated”) to save engaged wear on the color cartridge for black-only pages. Several seconds are characteristically taken to complete a switch back and forth between the color and monochrome modes and this switching consequently delays a print-job. During this switch the color cartridge as well as other printer components may experience additional wear. Both the engaged wear and the additional wear occur with both two-cartridge (separate black and color) printers and all-in-one cartridge printers (combined black and color). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure is better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other. Rather, emphasis has instead been placed upon clearly illustrating the claimed subject matter. Furthermore, like reference numerals designate corresponding similar parts through the several views. 
         FIG. 1  is a simplified block diagram of an example print system with a ratio-based adaptive switching technique illustrated by hardware components; 
         FIG. 2  is a simplified block diagram of the example print system of  FIG. 1  with a ratio-based adaptive switching technique illustrating the functionality of the print system in hardware and software modules; 
         FIG. 3  is a block diagram of an example computer readable medium with processor executable instructions organized into sub modules to implement a ratio-based adaptive switching technique; 
         FIG. 4  is an example state transition diagram showing a current printer mode on the horizontal axis and a determined cM/pN ratio on the vertical axis; 
         FIG. 5  is flowchart of an example ratio-based adaptive switching technique used to switch between printer modes; and 
         FIG. 6  is a flow chart of an example alternative ratio-based adaptive switching technique with additional possible operations that may be included to influence threshold values. 
     
    
    
     DETAILED DESCRIPTION 
     Because switching impacts printing performance and creates unwanted noise, users prefer minimal switching between modes and thus a color cartridge may be engaged (de-alienated) by default. Unfortunately, in some usage patterns of a printer, when a color cartridge is engaged to prevent switching, a color cartridge may wear out before its color toners are depleted. This premature wear-out is not desired by users of the printer. Accordingly, it is very difficult to keep printing performance acceptable while at the same time minimizing unneeded wear on the color cartridges. 
     To address these issues, a printing system having an adaptive switching technique based on a ratio of two recorded parameters that indicate wear is disclosed herein. The ratio is used to balance the optimization of both print-job performance and excess color cartridge wear. This dynamic ratio-based adaptive switching technique is used for determining when and how to dis-engage (alienate or switch-out) color cartridges to minimize excess wear. The two recorded parameters are the total number of pages printed (pN) and the number of black-only monochrome pages printed in color mode (cM). A ratio of cM to pN (cM/pN) is computed and compared to two thresholds separated by a hysteresis window. When the largest threshold is exceeded then the color cartridges are dis-engaged (alienated) to preserve color cartridge life by reducing unnecessary wear when printing monochrome pages. Once the color cartridges are not printing monochrome pages, the ratio cM/pN begins to drop. Once the lower of the two thresholds is reached, the color cartridges are engaged (de-alienated) or switched back in during monochrome printing to minimize the print-job performance impact. This ratio-based adaptive switching technique maintains a balance between both color and color mode monochrome printing, and color and black-only monochrome printing. More specific detail of example implementations and various possible modifications follow in the detailed description of the drawings. 
     For instance,  FIG. 1  is a simplified block diagram of an example print system  100  with a ratio-based adaptive switching technique  10  illustrated with hardware components. Print system  100  includes a computing unit  110  and a printing unit  150 . The computing unit  110  may include a panel interface (Panel I/F)  108  typically coupled to a panel  160 , such as an LCD, LED, plasma, OLED, AM-LED, IPS, or other display to provide visual indications of progress, options, and supply readiness to a user. Also, the computing unit  110  through and external display interface (EXT. D I/F)  106  typically receives one or more print-jobs  140  from one or more data processors  112 . Data processors may encompass a personal computer, a laptop, cell phone, print server, cloud-based server, and other equivalent computer systems that process various electronic data into printable content. The print-jobs  140  may contain monochrome-only (e.g., black-only), color-only, or mixed monochrome and color data-sets. Computing unit  110  includes one or more CPUs  124  having one or more cores capable of executing one or more software threads of instructions. The computing unit  110  and the printing unit  150  may be typically electronically coupled via a data bus  130  through a print interface  112 . 
     Computing unit  110  may include tangible, non-transitory computer-readable medium (CRM)  120 , such as read-only memory (ROM)  122 , random-accessible memory (RAM)  124  (such as DRAM and SRAM), hard disk drives (HDD)  120 , and external memories through an external interface (Ext. I/F)  128 . The external interface may connect to external SCSI, ATA, USB, Firewire, network based, cloud-based, and other forms of remote memory known to those of skill in the art. The CRM  120  contains instructions in the form of computer executable code that when read by a processor, such as CPU  124 , allows the processor to execute one or more software routines or modules, such as ratio-based adaptive switching technique  10 . 
     CRM  120  allows for storage of one or more sets of data structures and instructions (e.g. software, firmware, logic) expressed or utilized by any one or more of the methodologies or functions described herein. The instructions may also reside, completely or at least partially, with the static memory, the main memory, and/or within the processor during execution by the computing system. The main memory, ROM  122  and RAM  124  and the CPU  124  memory also constitute computer readable medium  120 . The term “computer readable medium”  120  may include single medium or multiple media (centralized or distributed) that store the one or more instructions or data structures. The computer readable medium  120  may be implemented to include, but not limited to, solid state, optical, and magnetic media whether volatile or non-volatile. Such examples include, semiconductor memory devices (e.g. Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-only Memory (EE-PROM), and flash memory devices), magnetic discs such as internal hard drives and removable disks, magneto-optical disks, and CD-ROM (Compact Disc Read-Only Memory) and DVD (Digital Versatile Disc) disks. 
     The various examples described herein may include logic or several components, modules, or constituents. Modules may constitute either software modules, such as code embedded in tangible non-transitory computer readable medium  120 ) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in certain manners. In one example, one or more CPUs  124  or one or more hardware modules of computing unit  110  may be configured by software (e.g. an application, or portion of an application) as a hardware module that operates to perform certain operations as described herein. 
     In some examples, a hardware module may be implemented as electronically programmable. For instance, a hardware module may include dedicated circuitry or logic that is permanently configured (e.g. as a special-purpose processor, state machine, a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC) to perform certain operations. A hardware module may also include programmable logic or circuitry (e.g. as encompassed within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations. It will be appreciated that the decision to implement a hardware module electronically in dedicated and permanently configured circuitry, or in temporarily configure circuitry (e.g. configured by software) may be driven by cost and time considerations. 
     The printing unit  150  may have one or more modes of operation, such as color mode  154  and monochrome mode  158 . In the color mode  154 , each of the black (“K”) and color (“C”, “Y”, “M”) cartridges  152  are engaged and available for use in printing documents of a print-job  140 . In monochrome mode  158 , the “K” cartridge  156  is engaged and available for use in printing while the color “C”, “Y”, “M” cartridges  157  are dis-engaged (alienated) and not available for use in printing. 
     The print system  100  may include one or more adaptive switching techniques  10  (see for instance, flowchart  500  in  FIG. 5  and flowchart  600  in  FIG. 6 ) selectable by users or to operate automatically and applicable for both two-part and all-in-one toner cartridge systems to minimize unneeded wear on the color cartridges  157  when they are not used during printing of monochrome pages. The various adaptive switching techniques  10  also improve print-job performance by minimizing when switching between color mode  154  and monochrome modes  158  is used. In one adaptive switching technique  10 , a ratio  306  ( FIG. 3 ) is determined by monitoring a number (cM  314 , a first behavior) of black-only monochrome (mono) pages printed while in color mode to the total number of pages printed (pN  302 , a second behavior). This ratio  306  (cM/pN) is indicative of the unneeded wear on the color cartridge  157  components. For instance, when the ratio is near 1, then there is excess unneeded wear on the color cartridges  157 . When the ratio is near 0, there is minimal unneeded wear on the color cartridges  157 . However, to come close to achieving this low ratio there may be frequent switching of the color cartridge  157  components in (de-alienate) and out (alienate) of a print path of print system  100 . This switching action may create undesired noise and print-job delay, thereby impacting print-job  140  performance. Hence, it is difficult to minimize the amount of additional wear on the color cartridges while keeping acceptable system performance. 
     One goal of the adaptive switching techniques  10  is to therefore to minimize the performance impact of switching between modes to when it is needed to preserve color cartridge life when there is adequate toner available. Accordingly, the adaptive switching techniques  10  optimize both print-job performance and excess cartridge wear of the system based on the determined ratio. The result is a balance between pages of both a) Color and Color Mode Mono, and 2) Color and Black (K)-only Mono. 
       FIG. 2  is a simplified block diagram of the print system  100  of  FIG. 1  with a ratio-based adaptive switching technique  10  illustrating the functionality of print system  100  in hardware and software modules or combinations of hardware and software modules depending upon specific implementations. Print system  100  includes computing unit  110  and printing unit  150 . Computing unit  110  includes CRM  120  with instructions  220  to implement a ratio-based adaptive switching technique  10  in the form of one or more modules, such as monitor behavior module  202 , determine ratio module  206  and optimize system module  204 . The various modules may be part of a single overall module or program or may be implemented as one or more sub-routines, object-oriented software objects, or separate autonomous program modules. Further various functionality of the modules may be shared, interoperate, or reside otherwise between the different modules. In one example, the computing unit  110  communicates with printing unit  150 . The printing unit  150  may include one or more hardware and/or software modules to implement a switching unit  210  to switch between the color mode  154  and the monochrome mode  158  of print system  100 . In some examples, the computing unit  110  may also be partially or fully implemented as part of printing unit  150 . Also, the CRM  120 , instructions  220 , and one or more of the various modules to implement a ratio-based adaptive switching technique  10  may also reside partially or fully in printing unit  150 . 
       FIG. 3  is a block diagram of an example computer readable medium  120  with processor executable instructions  220  organized into sub modules to implement a ratio-based adaptive switching technique  10  that balances print-job performance and component wear. 
     In module  312 , the instructions monitor a total number (pN) of printed pages  302  performed by print system  100  with both color mode  154  and monochrome mode  158  and a number (cM) of monochrome pages performed by print system  100  in a color mode  154 . In module  314 , the instructions  220  determine a ratio of cM  304  to pN  302  (cM/pN)  306 . In module  316 , the instructions  220  select the print system  100  to select the color mode  154  when the ratio is less than a first threshold. In module  318 , the instructions select the print system  100  to select a monochrome mode  158  when the ratio  306  is more than second threshold. In some example implementations, there may be more than one switching technique used to determine the current printing mode as discussed below. Therefore, the print system  100  may include more than one adaptive switching technique  10  and each technique may share or include their own unique counters (cM, pN) and threshold values. 
       FIG. 4  is an example state transition diagram  400  showing the current printer mode  404  on the horizontal axis and the determined cM/pN ratio  306  on the vertical axis. The current printer mode may also encompass selection a default or “home” printer mode, which could be either color mode  154  or monochrome-only mode  158 . In this example, print system  100  may change the default home mode to optimize for the current content type that users are most printing. This change of default home mode may be the most optimal for print-job  140  performance. In some examples, however, it may be that the default home mode always remains color mode  154 , and that on the receipt of a monochrome-only job, the print system  100  switches to monochrome-only mode  158 . In other examples, the default home mode may be monochrome-only mode  158  and the print system  100  switches to color mode  154  when a color job arrives  456 . 
     The vertical axis of cM/pN ratio  306  includes a first threshold  410  and a greater second threshold  412 , the difference between the two thresholds create a hysteresis region  414 . In general, a lower threshold value indicates more switching may occur, a greater threshold value indicates a desire for better print-job performance. To begin with, a printer system  100  with new black  156  and color  157  cartridges may typically initialize the start mode  406  of current printer mode  404  in color mode  154 . As various print-jobs  140  are received, including when monochrome job arrives  454 , the computing unit  110  tracks the total number of pages printed pN  302  and the number cM  304  of black-only or monochrome pages printed in color mode  154  of the print system  100 . The ratio  306  of cM to pN will increase when there is a greater number of monochrome pages being printed than when there are pages with color being printed while in color mode  154 . As more pages with color are printed and correspondingly less monochrome pages printed, the ratio  306  will decrease. 
     Once the ratio  306  reaches a first threshold  410  and a second threshold  412 , depending on the current printer mode  404  state, different actions will occur. For instance, while in color mode  154 , when a monochrome job, such as monochrome job  420  arrives while the ratio  306  is less than the second threshold  412 , the current printer mode  404  remains in the color mode  154  state while the ratio  306  increases due to the monochrome pages being printed while in color mode  154 . However, once the ratio  306  increases beyond the second threshold  412 , such as by printing mixed black and color print-jobs with more black than color pages, and then a further monochrome job  422  arrives, the print system  100  changes the current printer mode  404  to monochrome mode  158  as shown by state arrow  424 . While in monochrome mode  158 , when monochrome print-jobs  140  arrive and are printed, the ratio  306  will decrease as the numerator cM stays constant while the denominator pN continues to increase. Note that, when a print-job with color job  456  arrives (as shown by state arrows  428 ,  430 , and  434 ) the print system  100  switches to color mode  154  to allow for the color printing. 
     Depending on the ratio  306  value with respect to the first threshold  410  and second threshold  412 , the printer may stay in color mode  154 , such as with state arrow  434 , or it may return to monochrome mode  158 , such as with state arrows  430  and  428 . Stated otherwise, once the ratio  306  has exceeded the second threshold  412 , the print system  100  will switch or transition to monochrome mode  158  upon receiving a monochrome print-job  140 . Once in the monochrome mode  158  after the second threshold  412  has been reached, printing of monochrome print-jobs will decrease the ratio  306 . Until the ratio  306  has decreased to the first threshold  410 , any print-job  140  received that has a color page will cause the print system  100  to temporarily transition (as shown by state arrows  428 ,  430 ) to color mode  154  to print the color pages and then transition back to monochrome mode  158  as the current printer mode  404  to reduce wear on the color cartridge  157  components. While in monochrome mode  158 , when the ratio  306  is less than the first threshold  410 , any received print-job  140  with a color page will cause the current printer mode  404  to switch non-temporarily back to color mode  154 , as shown by state arrow  434 . 
     In some example implementations of print system  100 , such as by user option selection or based on the expected type of print-jobs to be received by print system  100 , the current printer mode  404  may selected to be monochrome mode  158  in alternative start mode  408 . Thus, the ratio  306  will stay at zero as all black-only or monochrome pages are printed in monochrome mode  158  and cM remains zero as pN increases. Once a color job arrives  456 , the print system  100  current printer mode  404  will transition to color mode  154  as shown by state arrow  436 . The ratio  306  may then continually increase as monochrome pages are printed in color mode  154 . This example implementation allows for minimizing wear of color cartridges  157  until an actual color job arrives  456 . 
     In another example implementation, the module  312  includes instructions  220  to have the print system  100  wait until the number of printed pages pN  302  exceeds a predetermined number before the instructions  220  in modules  316  and  318  are executed by the processor to select the print system modes (i.e. color mode  154 , monochrome mode  158 ). 
     In yet another example, the instructions  220  may include an additional module to analyze actual usage patterns of the print system  100  and adjust one or both the first threshold  410  and the second threshold  412  to reduce transitions between the color mode and the monochrome mode and thereby minimize an amount of color cartridge  157  life while the print system  100  prints monochrome pages. Also, the instructions  220  may also consider component life within cartridges  152 , such as toner and wear components, and adjust one or both the first threshold  410  and the second threshold  412  based at least partially on the component life. For instance, if an estimated life of the toner remaining in a color cartridge  157  is less than an estimated remaining life of the wear components of the color cartridge  157 , or the trend of the toner life is decreasing faster than the trend of the remaining life of the wear component then the second threshold  412  may be raised to keep print system  100  performance as the color toner will likely run out before the wear components wear out. Alternatively, the first threshold  410  may be raised to reduce the hysteresis region to allow print system  100  to default back to color mode more quickly when a color job arrives  456  as the color cartridge  157  may take on more wear before the color toner is expected to expire. In yet another example, both the first threshold  410  and the second threshold  412  may be raised to emphasize print performance over component wear. 
     If the estimated wear life is less than the estimated toner life and/or the trend is that the estimated wear life is decreasing faster than the estimated toner life, either or both the first threshold  410  and the second threshold  412  may be reduced to cause the print system  100  to have the current printer mode  404  be in monochrome mode  158  as it would appear from the usage patterns that most current print-jobs are monochrome and it would be prudent to stay in the monochrome mode  158  as a default to emphasize decreased component wear over print performance. 
     In fact, some example implementations may include a learning system to continually analyze usage patterns of the print system  100  and have the learning system dynamically optimize performance behavior based on real-time usage of the print system  100 . For instance, normally, when the second threshold  412  is reached and it is determined to switch to monochrome mode  158  from color mode  154 , it may be assumed that the print system  100  will switch back to color mode  154  eventually. Therefore, one may assume that any switch from color mode  154  to monochrome mode  158  will also have a monochrome mode  158  to color mode  154  switch as well. Accordingly, if a final page of a print-job  140  is often monochrome, one can relax this assumption and get more aggressive to lower the setting of the second threshold  412  and perhaps also the first threshold  410  to trigger a faster change to monochrome mode  158  because the overall cost to print-job performance is likely to be lower as it appears most print-jobs are monochrome only or mostly monochrome. 
     For print system  100 , an example learning system may thus detect that the final page before a spin-down of the paper feed components is often or usually monochrome. Perhaps in this situation, a user is printing a set of letters where the first page of a letter has a color logo and all following pages of the letter are monochrome. Thus, most of the pages of the set of letters may be assumed to be monochrome and as such, a switch to color mode  154  to print the color logo and a quick switch back to monochrome mode  158  for the monochrome pages can reduce wear on the color components without significantly reducing the overall print system  100  performance. Consequently, a learning system may look for opportunistic usage patterns and adjust the threshold levels accordingly to balance the print-job performance and cartridge wear to match more closely current usage patterns of print system  100 . 
     Therefore, a print system  100  may include a printing unit  150  to print an image on a recording medium in a color mode  154  or a monochrome mode  158 . The printing unit  150  may include a switching unit  210  to switch the printing unit  150  between the color mode  152  and the monochrome mode  158 . A computing unit  110  is configured with instructions to perform operations. Such operations include instructions to monitor a number (cM)  304  of monochrome pages printed in the color mode  154  and a total number (pN)  302  of printed pages. The instructions also determine a ratio  306  cM/pN that is indicative of unnecessary excess cartridge  156 ,  157  wear of the print system. The instructions then optimize print-job  140  performance and cartridge  156 ,  157  wear of the print system based on the determined ratio  306 . In some examples, the computing unit  110  does not optimize until at least a predetermined total number of printed pages pN  302  has accumulated to better derive an accurate understanding of a standard usage of the print system  100 . In yet other examples, the computing unit  110  optimizes by minimizing both the number of transitions between the color mode  154  and the monochrome mode  158  and the life of a color cartridge  157  in the print system  100  that is used while printing monochrome pages. As noted above, the computing unit  110  may also be configured to perform a learning system to allow for dynamically optimizing the print-job performance and the cartridge wear based on real-time usage of the print system  100 . Accordingly, the print system  100  may include more than one method of switching between color mode  154  and monochrome mode  158  and each method may include their own unique counters and thresholds. 
       FIG. 5  is flowchart  500  of an example ratio-based adaptive switching technique  10  to change between current printer modes. When the adaptive switching technique  10  begins in start block  502 , it begins to monitor print system  100  for the total number of printed pages, pN  302 , in both color mode  154  and monochrome mode  158  as well as the number of monochrome pages, cM  304 , printed in color mode  154 . In decision block  506 , a ratio of cM/pN is determined whether it is less than or not a first threshold  410  and if so, selecting the color mode  154  of the print system  100  in block  508 . If not less, then in decision block  510  the ratio cM/pN is determined whether it is greater or not than a second threshold  412  and if so, selecting the monochrome mode  158  of the print system  100  in block  512 . If not greater, and after the color or monochrome modes have been selected in blocks  508 ,  512 , respectively, the adaptive switching technique  500  continues to block  514  to keep the current printer mode  404  and then back to block  504  to continue monitoring pN  302  and cM  304  and checking if the ratio  306  of cM/pN to the first and second thresholds in decision blocks  506 ,  510 . 
       FIG. 6  is a flow chart  600  of an example alternative adaptive switching technique  10  with additional possible operations that may be included or used to influence the first and second threshold values. For instance, once the alternative adaptive switching technique  10  begins in start block  602 , it similarly monitors pN  302  and cM  304  in block  504  as described for  FIG. 5 &#39;s flow chart. However, before checking the ratio  306  of cM/pN to the first threshold  410  and the second threshold  412  in decision blocks  506  and  510 , in decision block  604  the alternative adaptive switching technique  600  waits until the total number of printed pages pN  302  exceeds a predetermined number before proceeding to determining if the ratio  306  against the first and second thresholds in blocks  506 ,  508 ,  510 ,  512 , and  514  as described for  FIG. 5 . Therefore, an alternative adaptive switching technique  10  may wait until the number of printed pages exceeds a predetermined number before the elements of determining are performed. 
     In some implementations, an alternative adaptive switching technique  10  may include a learning module that in block  606  allows for monitoring real-time usage patterns of the print system  100  and in block  608  modifying at least one of the first threshold  410  and the second threshold  412  to minimize at least one of cartridge  156 ,  157  wear or optimize print-job time performance of the print system  100  based on the real-time usage patterns. Block  608  may in some implementations in block  610  also check the level or age of at least one component in a cartridge of the print system  100  and then modify at least one of the first threshold and the second threshold based on the level or age of at least one component in a cartridge of the print system. For example, if the color toner has an expiration date that is soon approaching and the timeframe to the expiration date is less than the expected time for wear out of the color cartridge  157  or the color toner level is low, then the first and second thresholds may be increased to keep emphasizing print-job performance as the color cartridge will need to be replace soon anyway. 
     In another implementation, the alternative adaptive switching technique  10  may include in block  612  of first selecting the monochrome mode  158  as the current printer mode  404  of the print system  100 . Then in block  614  print-jobs  140  for the print system  100  are received. In decision block  616 , the print-job  140  is checked to see if it is a color print-job and when a color page is to be printed and if so in block  618  the color mode  154  is selected as the current printer mode  404  for the remaining color print-job  140  before returning to block  504  and monitoring of the behavior of print system  100  using the pN and cM variables. If not, then decision block  616  proceeds to block  514  to keep the current printer mode  404 . 
     In summary, the adaptive switching techniques  10  and hardware and software logic discussed above allows for managing the wear life an any print system  100  that has at least two possible methods of behavior (e.g. total number of printed pages (pN)  302  and number of monochrome pages printed in color mode (cM)  304 ) that may be controlled and/or optimized based on the real-time usage of the print system  100 . In the given examples, a ratio  306  of cM to pN (cM/pN) may be controlled through use of thresholds which may be passively set or actively adjusted to achieve a balance between the print-job performance and reduced wear of color cartridge components based on usage, usage patterns, component life, amount of toner. Allowing for actively adjusted thresholds, the entire print system  100  may be analyzed and real-use print usage patterns determined. These print usage patterns may then be used to vigorously adjust the thresholds and thus the behavior of the print system  100  may be dynamically optimized for real-use patterns along with the real-time usage. 
     While the claimed subject matter has been particularly shown and described with reference to the foregoing examples, those skilled in the art will understand that many variations may be made therein without departing from the intended scope of subject matter in the following claims. This description should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing examples are illustrative, and no single feature or element is central to all possible combinations that may be claimed in this or a later application. Where the claims recite “a” or “a first” element of the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.