Patent Publication Number: US-11020964-B2

Title: Modifying a firing event sequence while a fluid ejection system is in a service mode

Description:
BACKGROUND 
     Fluid ejection dies may be implemented in fluid ejection devices and/or fluid ejection systems to selectively eject/dispense fluid drops. Example fluid ejection dies may include nozzles, ejection chambers and fluid ejectors. In some examples, the fluid ejectors may eject fluid drops from an ejection chamber out of the orifice. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure herein is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements, and in which: 
         FIG. 1  illustrates an example fluid ejection system to purge fluid from the fluid ejection system during a servicing mode; 
         FIG. 2A  illustrates an example cross-sectional view of an example ejector type actuator; 
         FIG. 2B  illustrates an example cross-sectional view of an example recirculation type actuator; 
         FIG. 3  illustrates an example fluid ejection die with multiple columns of actuators; 
         FIG. 4  illustrates an example portion of a fluid ejection die with fluid ejector type actuators and recirculation type actuators; 
         FIG. 5A  illustrates an example firing event sequence that includes firing data packets for fluid ejector type actuators and recirculation type actuators; 
         FIG. 5B  illustrates an example modified firing event sequence of  FIG. 5A ; 
         FIG. 6  illustrates an example portion of a fluid ejection die with HDW (high drop weight) fluid ejector type actuators and LDW (low drop weight) fluid ejector type actuators; 
         FIG. 7A  illustrates an example firing event sequence that includes firing data packets for HDW fluid ejector type actuators and LDW fluid ejector type actuators; 
         FIG. 7B  illustrates an example modified firing event sequence of  FIG. 7A ; 
         FIG. 7C  illustrates an example modified firing event sequence of  FIG. 7B . 
         FIG. 8A  illustrates an example method for purging fluid from a fluid ejection system; 
         FIG. 8B  illustrates an example methods for purging fluid from a fluid ejection system based on an actuator type of each actuator; 
         FIG. 8C  illustrates an example methods for purging fluid from a fluid ejection system based on the column and/or actuator group of a fluid ejection die associated with each actuator; and 
         FIG. 8D  illustrates an example methods for purging fluid from a fluid ejection system based on actuator type and column and/or actuator group of a fluid ejection die associated with each actuator. 
     
    
    
     Throughout the drawings, identical reference numbers designate similar, but not necessarily identical elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover the drawings provide examples and/or implementations consistent with the description. However, the description is not limited to the examples and/or implementations provided in the drawings. 
     DETAILED DESCRIPTION 
     Examples provide for a fluid ejection system to modify a firing event sequence of a group of fluidic actuators of a fluid ejection die to increase the efficiency for purging fluid (e.g., shipping fluid or ink) from the fluid ejection system. In some examples, the fluid ejection system can purge fluid when the fluid ejection system is operating in a servicing mode. In some examples, a fluid ejection system can modify a firing event sequence based on a fluidic actuator type of each fluidic actuator. In other examples, a fluid ejection system can modify a firing event sequence based on a column and/or fluidic actuator group of a fluid ejection die each fluidic actuator is associated with. In yet other examples, a fluid ejection system can modify a firing event sequence based on a fluidic actuator type and a column and/or fluidic actuator group of a fluid ejection die each fluidic actuator is associated with. 
     Examples as described recognize that a fluid ejection system (e.g., a printer system) can include shipping fluid. Shipping fluid is fluid that can help maintain functionality of each fluidic actuator of a fluid ejection die (e.g., a print-head die). For example, shipping fluid can ensure that a orifice or a chamber of an fluidic actuator does not dry out prior to the first installation of the fluid ejection system. However, the fluid ejection systems do not utilize shipping fluid during normal operations. As such, in some examples, the fluid ejection systems may purge shipping fluid before initiating a normal mode of operations (e.g., during a servicing mode). Current implementations for a fluid ejection system to purge shipping fluid can be overly time consuming and inefficient in the utilization of the resources of the fluid ejection system. Among other benefits, examples are described that enable the fluid ejection system to modify a firing event sequence of a group of fluidic actuators of a fluid ejection die to increase the efficiency for purging shipping fluid from the fluid ejection system. The fluid ejection system can purge shipping fluid when the fluid ejection system is operating in a servicing mode. 
     System Description 
       FIG. 1  illustrates an example fluid ejection system to purge fluid from the fluid ejection system during a servicing mode. As illustrated in  FIG. 1 , fluid ejection system  100  can include controller  102  and fluid ejection die  104 . Controller  102  can implement processes and other logic to manage operations of the fluid ejection system  100 . For example, controller  102  can transmit firing event sequence  108  to control fluid ejection die  104  to fire/eject/recirculate fluid out of fluidic actuator(s) or actuator(s)  106 . As herein described, any fluid (e.g., ink or shipping fluid), can be fired out of actuator(s)  106 . In some examples, controller  102  can transmit firing event sequence  108  to control fluid ejection die  104  to purge fluid (e.g., shipping fluid) out of fluid ejection die  104 . In other examples, controller  102  can modify firing event sequence  108  to increase the efficiency for purging shipping fluid from fluid ejection die  104 . Additionally, in a variation of such examples, firing event sequence  108  is associated with a normal mode of operations. In some examples, controller  104  can include a processor to implement the described operations of fluid ejection system  100 . 
     Actuator(s)  106  can include a nozzle or an orifice, a chamber and an actuator component or element. Each actuator  106  can receive fluid from a fluid reservoir. In some examples, the fluid reservoir can be ink feed holes or an array of ink feed holes. In some examples, the fluid can be ink (e.g., latex ink, synthetic ink or other engineered fluidic inks). In other examples, the fluid can be shipping fluid. Each actuator  106  can be associated or assigned to an identifier. For example, each actuator  106  can be assigned an address. 
     Fluid ejection system  100  can fire fluid from the orifice of actuator(s)  106  by forming a bubble in the chamber of actuator(s)  106 . In some examples, the fluid ejection component can include a actuator element. Controller  102  of fluid ejection system  100  can drive a signal to fluid ejection component to drive/eject the fluid out of the orifice of actuator(s)  106 . 
     In some examples, firing event sequence  108  can specify which actuator  106  is to eject/recirculate fluid. For example, firing event sequence  108  can include firing instructions or firing data packets. Each firing data packet can include firing data that can control fluid ejection die  104  to drive a signal (e.g., power from a power source or current from the power source) to the fluid actuator element to fire/eject the fluid in the chamber of actuator  106 . Furthermore, the firing data packets can include specific addresses or identifiers that are associated with specific actuator(s)  106 . As such, identifiers or addresses included in the firing data packets can instruct fluid ejection die  104  which specific actuator is to eject/recirculate. In some examples, controller  102  can transmit firing event sequence  108  to control fluid ejection die  104  the order or sequence each actuator  106  is to fire/eject/recirculate fluid. 
     In some examples, fluid ejection die  104  can include multiple actuator groups. In such examples, controller  102  can transmit firing event sequence  108  to each actuator group of fluid ejection die  104 . In response to each actuator group of fluid ejection die  104  receiving the firing event sequence  108 , the each actuator group can determine which actuator to fire and/or in what order each actuator is to fire. In a variation of such examples, each actuator group of fluid ejection die  104  may determine which actuator within the actuator group is to fire and in which order based on the address conveyed by controller  102  on firing event sequence  108 . 
     Fluid ejection system  100  can have multiple operational modes. For example, fluid ejection system  100  can operate in a normal mode. In other examples, fluid ejection system  100  can operate in a service mode. Fluid ejection system  100  can purge fluid (e.g., shipping fluid) out of the orifices of each actuator from fluid ejection die  104  when fluid ejection system  100  is operating in a service mode. For example, controller  102  can determine the operational mode fluid ejection system  100  is operating in. In response to controller  102  determining fluid ejection system  100  is operating in a service mode, controller  102  can transmit firing event sequence  108  to control fluid ejection die  104  to purge fluid from fluid ejection die  104 . In response to fluid ejection die  104  receiving firing event sequence  108 , fluid ejection die  104  can drive a signal to actuator(s)  106  to fire/eject fluid. In some examples, controller  102  can modify firing event sequence  108  that is associated with a normal mode and transmit the modified firing event sequence  108  to fluid ejection die  104  to control fluid ejection die  104  to purge fluid. 
     In some examples, fluid ejection system  100  can have multiple service modes and each service mode could correspond to a purging of a different type of fluid. For example, a first service mode can correspond to controller  102  instructing fluid ejection die  104  to purge shipping fluid. Additionally, a second service mode can correspond to controller  102  instructing fluid ejection die  104  to purge ink. Additionally, in such examples, fluid ejection system  100  can modify a firing event sequence of a group of fluidic actuators  106  to increase the efficiency for purging fluid in each service mode. 
       FIG. 2A  illustrates an example cross-sectional view of an example ejector type actuator. As illustrated in  FIG. 2A , actuator  208  includes orifice  200 , chamber  202 , and fluid actuator element  206 . In some examples, as illustrated in  FIG. 2A , fluid actuator element  206  may be disposed proximate to ejection chamber  202 . 
     In some examples, actuator  208  can be a fluid ejector type. The fluid ejector type actuator  208  can eject drops of fluid from chamber  202  through an orifice  200  by fluid actuator element  206 . Examples of fluid actuator element  206  of a fluid ejector type actuator  208  include a thermal resistor based actuator, a piezo-electric membrane based actuator, an electrostatic membrane actuator, magnetostrictive drive actuator, and/or other such devices. 
     In examples in which fluid actuator element  206  may include a thermal resistor, a controller (e.g., controller  102 ) can control the fluid ejection die to drive a signal (e.g., power from a power source or current from the power source) to electrically actuate fluid actuator element  206 . In such examples, the electrical actuation of fluid actuator element  206  can cause formation of a vapor bubble in fluid proximate to fluid actuator element  206  (e.g., chamber  202 ). As the vapor bubble expands, a drop of fluid may be displaced in chamber  202  and ejected through the  200 . In this example, after ejection of the fluid drop, electrical actuation of fluid actuator element  206  may cease, such that the bubble collapses. Collapse of the bubble may draw fluid from fluid reservoir  204  into chamber  202 . In this way, in such examples, a controller (e.g., controller  102 ) can control the formation of bubbles in chamber  202  by time (e.g., the time for which the actuator element is actuated) or by signal magnitude or characteristic (e.g., different levels of power). 
     In examples in which the fluid actuator element  206  includes a piezoelectric membrane, a controller (e.g., controller  102 ) can control the fluid ejection die to drive a signal (e.g., power from a power source or current from the power source) to electrically actuate fluid actuator element  206 . In such examples, the electrical actuation of fluid actuator element  206  can cause deformation of the piezoelectric membrane. As a result, a drop of fluid may be ejected out of the orifice or bore of orifice  200  due to the deformation of the piezoelectric membrane. Returning of the piezoelectric membrane to a non-actuated state may draw additional fluid from fluid reservoir  204  into chamber  202 . 
     In some examples, the fluid ejector type actuator  208  can be a HDW (high drop weight) fluid ejector type actuator  208 . In other examples, the fluid ejector type actuator  208  can be a LDW (low drop weight) fluid ejector type actuator  208 . In some examples, the HDW fluid ejector type actuator  208  can include orifice  200  with a larger orifice or different orifice geometry to eject higher weighted or larger sized fluid drops than the LDW fluid ejector type actuator  208 . In other examples, the HDW fluid ejector type actuator  208  can utilize more power to eject higher weighted or larger sized fluid drops than the LDW fluid ejector type actuator  208 . In yet other examples the HDW fluid ejector type actuator  208  can utilize more power and can include a larger orifice or different orifice geometry to eject higher weighted fluid drops than the LDW fluid ejector type actuator  208 . 
     In some examples, the fluid ejection die can include LDW fluid ejector type actuator  208 . In other examples, the fluid ejection die can include HDW fluid ejector type actuator  208 . In yet other examples, a fluid ejection die can include both a HDW fluid ejector type actuator  208  and a LDW fluid ejector type actuator  208 . 
     In some examples, the actuator can be a recirculation type actuator.  FIG. 2B  illustrates an example cross-sectional view of an example recirculation type actuator. The recirculation type actuator  216  may recirculate or pump fluid within one or more chambers  210  when fluid actuator element  212  fires. In such examples, recirculation type actuator  216  does not include an orifice (e.g., orifice  200  of  FIG. 2A )  200 . Similar to the fluid ejector type actuator  208 , examples of actuator element  212  of a recirculation actuator type actuator  216 , can include a thermal resistor based actuator, a piezo-electric membrane based actuator, an electrostatic membrane actuator, magnetostrictive drive actuator, and/or other such devices. 
     A fluid ejection die (e.g., fluid ejection die  104 ) can include multiple columns of actuators (e.g., actuator(s)  106 ). For example,  FIG. 3  illustrates an example fluid ejection die with multiple columns of actuators. As illustrated in  FIG. 3 , fluid ejection die  300  can include columns  302 ,  306 ,  308  and  312 . Furthermore, as illustrated in  FIG. 3 , F.R. (fluid reservoir)  304  is operatively coupled to column  302  and column  306  and F.R.  310  is operatively coupled to column  308  and column  312 . In some examples, a fluid ejection die can have multiple columns of actuators and each column of actuators can have multiple groups of actuators. For example, column  302 , column  306 , column  308  and column  312  can each include multiple groups of actuator(s). In other examples, a fluid ejection die can include a column of multiple groups of actuator. In some examples, a fluid ejection die can include a column of actuators. In other examples, a fluid ejection die can have an array of actuators. In yet other examples, a fluid ejection die can include F.R.  304  and  310  are ink feed holes. 
     In some examples, the identifier or address of each actuator (e.g., actuator(s)  106 ) can be based on the location of the actuator on the fluid ejection die. For example, the address of each actuator can be based on the row of the column that each actuator is located on. In another example, the address of each actuator can be based on which column each actuator is located on. In some examples, actuators on a fluid ejection die can share addresses or identifiers. For example, a fluid ejection die can include multiple columns of actuators and each column includes multiple groups of actuators. In such an example, each actuator group has a single column of actuators. Furthermore, each actuator of each actuator group with the same row location can be assigned the same address. 
     The fluid ejection system (e.g., the controller) can modify the firing event sequence associated with a normal mode of operations based on the actuator type of the actuator to more efficiently purge fluid out of the fluid ejection system. For example, a controller (e.g., controller  102 ) can determine, for each firing data packet of a firing event sequence, the actuator type associated with the address or identifier of each actuator (e.g., whether the actuator is a fluid ejector actuator, a recirculation actuator, high drop weight actuator or a low drop weight actuator). Additionally, the controller can modify the firing event sequence associated with a normal mode of operations, by removing or adding a firing data packet to the firing event sequence, based on the determined type of actuator. In some examples, the controller can add an additional address associated with an actuator to a firing data packet of a firing event sequence. 
     In some examples, a fluid ejection system undergoing going fluid purge, may include a fluid ejector type actuator and a type recirculation actuator.  FIG. 4  illustrates an example portion of a fluid ejection die with a fluid ejector type actuator and a recirculation type actuator. In some examples, the fluid ejector type actuator is a HDW fluid ejector type actuator. In other examples, the fluid ejector type actuator is a LDW fluid ejector type actuator. In yet other examples, the fluid ejection die can include both a HDW fluid ejector type actuator and a LDW fluid ejector type actuator. 
     As illustrated in  FIG. 4 , the example portion of a fluid ejection die includes fluid reservoir  416 . Fluid reservoir  416  is associated with actuator group  402 ,  404 ,  406  and  408 . Actuator group  402  and  406 , together represent a column of actuators, and actuator group  404  and  410 , together represent another column of actuators. Each actuator group  402 ,  404 ,  406  and  408  can include firing components (e.g.,  414 A- 414 H), fluid actuator elements (e.g.,  412 A- 412 H), fluid ejector type actuators (e.g.,  410 A,  410 C,  410 E,  410 G) and recirculation type actuators (e.g.,  410 B,  410 D,  410 F, and  410 H). As illustrated in  FIG. 4 , in some examples, each fluid ejector type actuator can be operatively coupled to a recirculation type actuator through a fluidic channel (e.g.,  418 ,  420 ,  422 ,  424 ,  426 ,  428 ,  430 ,  432 ,  434 ,  436 ,  438 ,  440 ,  442 ,  444 ,  446 , and  448 ). For example, fluid ejector type actuator  410 C is operatively connected with recirculation type actuator  410 D by fluidic channel  416 . 
     Additionally, as illustrated in  FIG. 4 , each firing component (e.g.,  414 A- 414 H) is operatively coupled to a fluid actuator element (e.g.,  412 A- 412 H), and each fluid actuator element is operatively coupled to an actuator (e.g., fluid ejector type actuator or recirculation type actuator). For example firing component  414 A is operatively coupled to fluid actuator element  412 A. Additionally, fluid actuator element  412 A is operatively coupled to fluid ejector type actuator  410 A. In some examples, each firing component can include FETS (e.g., JEFT or MOSTFET) to drive a signal to a corresponding actuator element. 
     In examples where the fluid ejection system includes a fluid ejector type actuator and a recirculation type actuator, the firing event sequence includes firing data packets that are addressed to recirculation type actuators and fluid ejector type actuators. For example,  FIG. 5A  illustrates an example firing event sequence that includes firing data packets addressed to fluid ejector type actuators and recirculation type actuators. As illustrated in  FIG. 5A , firing event sequence  516  includes firing data packets or FPG (fire pulse group)  500 -FPG  514 . Each FPG can include firing data that corresponds to actuating or not actuating ejecting or recirculating actuators. Additionally, each FPG can include identifiers or addresses of an actuator to be actuated. For example, FPG  500  is addressed to a fluid ejector type actuator with the address of A 0 . If FPG  500  includes firing data that corresponds to actuating actuators, then FPG  500  can control the fluid ejection die or an actuator group to fire/eject a fluid ejector type actuator with the address of A 0 . In examples where the fluid ejection die includes actuator groups with actuators that share addresses, then a firing data packet that includes an address can cause all actuators with the same address in every actuator group to fire/eject or not fire/eject. For example, a controller (e.g., controller  102 ) can transmit a firing data packet addressed to A 0  to the fluid ejection die. As a result, the fluid ejection die can drive a signal to fire all actuators in each actuator group assigned to the address A 0 . 
     However, as described above, recirculation type actuators do not eject fluid. Firing or triggering recirculation type actuators to recirculate would not help purge the fluid ejection system of fluid (e.g., shipping fluid) and instead would waste resources of the fluid ejection system. As such, when the fluid ejection system is initiating or already operating in a service mode to purge fluid (e.g., shipping fluid), the controller can determine and remove firing data packets addressed to recirculation type actuators (e.g., FPG  502 , FPG  506 , FPG  510 , and FPG  514 ). 
     In some examples, the fluid ejection system can take into consideration resource limitations of the fluid ejection system when purging its system of fluid (e.g., shipping fluid). Examples of limitations of the fluid ejection system include fluidic limitations, data rate limitations, and power supply and power parasitic limitations. Fluid limitations, based in part on the chamber refill rates, can determine the maximum frequency at which any given actuator can fire. 
     Power supply and power parasitic limitations can limit how many actuators of a multi-actuator-group fluid ejection die that share addresses, can fire simultaneously, per firing data packet. For example, with reference to  FIG. 4 , a fluid ejection system can have multiple groups of actuators, and the actuators of each actuator group can share an address (e.g., actuator  410 A of actuator group  402 ,  404 ,  406  and  408 , all share the same address). Additionally, the fluid ejection system can have a power supply limitation that permits 50% of actuators with addresses specified in a firing data packet can fire. Meaning, if a controller (e.g., controller  102 ) transmits a firing data packet addressed to actuator  410 A to the fluid ejection die (e.g., fluid ejection die  104 ), the fluid ejection die will drive a signal to two out of the four actuator  410 A of the four actuator groups ( 402 ,  404 ,  406  and  408 ). Moreover, to trigger all four actuator  410 A to fire, the controller can transmit a second firing data packet addressed to actuator  410 A to the fluid ejection die and/or to the actuator groups that have not had an actuator  410 A fire yet. 
     Data rate limitations can limit the maximum frequency at which firing data packets can be sent to the fluid ejection die at a given time. For example, as illustrated in  FIG. 5A  and  FIG. 5B , the maximum number of firing data packets or the maximum length of the firing event sequence a controller can transmit to a fluid ejection die or actuator group at a given time is 8 firing data packets. In some examples, as similarly described above, removing firing data packets from a firing event sequence can underutilize the resources of the fluid ejection system (e.g., not maximizing the data rate limitations of the fluid ejection system). As such, in such examples, the controller can add more firing data packets to fully utilize the resources of the fluid ejection system. 
     Examples of a controller adding more data packets to fully utilize the resources of a fluid ejection system is illustrated in  FIG. 5B .  FIG. 5B  illustrates an example modified firing event sequence of  FIG. 5A . As described earlier, the controller has removed FPG  502 , FPG  506 , FPG  510 , and FPG  514  (firing data packets associated with recirculation) from firing event sequence  516 . As such, to fully utilize the resources of the fluid ejection system, the controller can add additional firing data packets to firing event sequence  516  that are addressed to fluid ejector type actuators (e.g., FPG  500 , FPG  504 , FPG  508  and FPG  512 ). As such, the data rate limitation of 8 firing data packets per given time is fully utilized, and the number of actuators that can and are ejecting/purging fluid out of the fluid ejection system has increased (e.g., 8 fluid ejector type actuators are being utilized as opposed to 4 fluid ejector type actuators per actuator group). 
     In some examples, a fluid ejection system undergoing fluid purge, may include a HDW (high drop weight) fluid ejector type actuator and a LDW (low drop weight) fluid ejector type actuator.  FIG. 6  illustrates an example portion of a fluid ejection die with a HDW fluid ejector type actuator and a LDW fluid ejector type actuator. As illustrated in  FIG. 6 , the example portion of a fluid ejection die includes fluid reservoir  616 . Fluid reservoir  616  is associated with actuator group  602 ,  604 ,  606  and  608 . Actuator group  602  and  606 , together represent a column of actuators, and actuator group  604  and  610 , together represent another column of actuators. Each actuator group  602 ,  604 ,  606  and  608  can include firing components (e.g.,  614 A- 614 H), fluid actuator elements (e.g.,  612 A- 612 H), HDW fluid ejector type actuators (e.g.,  610 A,  610 C,  610 E,  610 G) and LDW fluid ejector type actuators (e.g.,  610 B,  610 D,  610 F, and  610 H). 
     Additionally, as illustrated in  FIG. 6 , each firing component (e.g.,  614 A- 614 H) is operatively coupled to a fluid actuator element (e.g.,  612 A- 612 H), and each firing ejector is operatively coupled to an actuator (e.g., HDW fluid ejector type actuator or LDW fluid ejector type actuator). For example firing component  614 A is operatively coupled to fluid actuator element  612 A and fluid actuator element  612 A is operatively coupled to HDW fluid ejector type actuator  610 A. In some examples, each firing component (e.g.,  614 A- 614 H) can include FETS (e.g., JEFT or MOSTFET) to drive a signal to a corresponding actuator element (e.g.,  612 A- 612 H). 
     In examples where the fluid ejection system includes a HDW fluid ejector type actuator and a LDW fluid ejector type actuator, the firing event sequence includes firing data packets that are addressed to LDW fluid ejector type actuators and HDW fluid ejector type actuators. For example,  FIG. 7A  illustrates an example firing event sequence that includes firing data packets for HDW fluid ejector type actuators and LDW fluid ejector type actuators. As illustrated in  FIG. 7A , the firing event sequence includes firing data packets or FPG (fire pulse group)  700 -FPG  714 . Each FPG can include firing data that corresponds to firing/ejecting fluid or to not fire/eject fluid. Additionally, each FPG can include identifiers or addresses of an actuator to be fired. For example, FPG  700  is addressed to a HDW fluid ejector type actuator with the address of A 0 . Additionally FPG  700  can include firing data that corresponds to firing/ejecting fluid. Taken together, FPG  700  can control the fluid ejection die or an actuator group to fire a HDW fluid ejector type actuator with the address of A 0 . 
     However, as described above, LDW fluid ejector type actuators do not eject as much fluid (e.g., shipping fluid) as HDW fluid ejector type actuators. Firing the LDW fluid ejector type actuators to purge fluid from the fluid ejection die would not be as efficient as firing the HDW fluid ejector type actuators to purge/eject fluid from the fluid ejection die. As such, when the fluid ejection system is initiating or already operating in a service mode to purge fluid (e.g., shipping fluid), the controller can determine and remove firing data packets addressed to LDW fluid ejector type actuators (e.g., FPG  702 , FPG  706 , FPG  710 , and FPG  714 ). 
     Examples of a controller can add more firing data packets to fully utilize the resources of a fluid ejection system (e.g., maximizing the data rate limits of the fluid ejection system), is illustrated in  FIG. 7B .  FIG. 7B  illustrates an example modified firing event sequence of  FIG. 7A . As described earlier, the controller has removed FPG  702 , FPG  706 , FPG  710 , and FPG  714  (firing data packets associated with recirculation) from firing event sequence  716 . As such, to fully utilize the resources of the fluid ejection system (e.g., to maximize the data rate limits), the controller can add additional firing data packets to firing event sequence  716  that are addressed to HDW fluid ejector type actuators (e.g., FPG  700 , FPG  704 , FPG  708  and FPG  712 ). As such, the resources of the fluid ejection system can be fully utilized (e.g., by utilizing the maximum data rate of the fluid ejection system), and more efficient actuators are ejecting/purging fluid out of the fluid ejection system. 
     Utilizing HDW fluid ejector type actuators consume more available resources (e.g., power) of the fluid ejection system than utilizing LDW fluid ejector type actuators. In some examples, a fluid ejection system that utilizes a firing event sequence with firing data packets addressed to only HDW fluid ejector type actuators (e.g., firing event sequence  716  of  FIG. 7B ), can result in consumption of a higher peak power than a firing event sequence with firing data packets addressed to only LDW fluid ejector type actuators or to LDW fluid ejector type actuators and HDW fluid ejector type actuators. In such examples, the controller can further modify the firing event sequence by adding to the firing data packets addresses of LDW fluid ejector type actuators. 
     Examples of a controller adding addresses or identifiers of to LDW fluid ejector type actuators to the HDW fluid ejector type actuator associated firing data packets of a firing event sequence, is illustrated in  FIG. 7C .  FIG. 7C  illustrates an example modified firing event sequence of  FIG. 7B . In such examples, the controller can add to FPG  700 , FPG  704 , FPG  708  and FPG  712 , addresses of the removed LDW fluid ejector type actuators. For example, the controller can add the A 1  address of LDW fluid ejector type actuator to FPG  700 ; the controller can add the A 3  address of LDW fluid ejector type actuator to FPG  704 ; the controller can add the A 5  address of LDW fluid ejector type actuator to FPG  708 ; and the controller can add the A 7  address of LDW fluid ejector type actuator to FPG  712 . As a result, there will be a lower peak power consumed by the fluid ejection system and greater utilization of all the fluid ejector type actuators of a fluid ejection die that includes HDW and LDW fluid ejector type actuators. 
     In some examples, the fluid ejection system can further specify which column which HDW or LDW fluid ejector type actuator is to be fired. In such examples, the fluid ejection die can include multiple columns of actuators (e.g.,  FIG. 6 ). In some examples each column of actuators can include multiple groups of actuators. In such examples, the controller can further include in each firing data packet of the firing event sequence, a column identifier or an actuator group identifier associated with the address assigned to each HDW or LDW fluid ejector type actuator. For example, referring to  FIG. 6  and FPG  700  of FIG. C, a controller can specify the HDW fluid ejector type actuators with the address A 0  (e.g., HDW fluid ejector type actuator  610 A) and LDW fluid ejector type actuators with address A 1  (e.g., LDW fluid ejector type actuator  610 B) of the right column are to fire, by including a column identifier associated with the right column into FPG  700 . In other examples, again referring to  FIG. 6  and FPG  700  of  FIG. 7C , a controller can specify the HDW fluid ejector type actuators with the address A 0  (e.g., HDW fluid ejector type actuators  610 A) and LDW fluid ejector type actuators with address A 1  (e.g., LDW fluid ejector type actuator  610 B) of actuator group  602  and  604  respectively are to fire, by including actuator group identifiers associated with actuator group  602  and  604  into FPG  700 . 
     Methodology 
       FIG. 8A  illustrates an example method for purging fluid from a fluid ejection system.  FIG. 8B  illustrates an example methods for purging fluid from a fluid ejection system based on an actuator type of each actuator.  FIG. 8C  illustrates an example methods for purging fluid from a fluid ejection system based on the column and/or actuator group of a fluid ejection die associated with each actuator.  FIG. 8D  illustrates an example methods for purging fluid from a fluid ejection system based on actuator type and column and/or actuator group of a fluid ejection die associated with each actuator. As herein described a firing event is when a drive bubble device ejects/fires/recirculates fluid. In the below discussions of  FIG. 8A-8D  may be made to reference characters representing like features as shown and described with respect to  FIGS. 1, 4, 5A, 5B, 6, 7A and 7B  for purposes of illustrating a suitable component for performing a step or sub-step being described. 
       FIG. 8A  illustrates an example method for purging fluid from a fluid ejection system. In some examples, fluid ejection system  100  can determine an operational mode ( 800 ). For example, controller  102  can determine an operational mode fluid ejection system  100  is to perform or is currently performing. Examples of operational modes include normal mode and service mode. The service mode can include fluid ejection system  100  purging fluid (e.g., shipping fluid) from fluid ejection die  104 . 
     In some examples, fluid ejection system  100  can include fluid ejection die  104  that includes multiple columns of actuators. In other examples, fluid ejection die  104  can include multiple groups of actuators. In yet other examples, fluid ejection die  104  can include multiple columns of actuators and each column of actuators can include multiple groups of actuators. For example, with reference to  FIG. 4 , the illustrated example portion of a fluid ejection die (e.g., fluid ejection die  104 ) can include actuator group  402 ,  404 ,  406  and  408 . Actuator group  402  and  406 , together represent a column of actuators, and actuator group  404  and  410 , together represent another column of actuators. 
     In response to fluid ejection system  100  determining fluid ejection system  100  is in a service mode, fluid ejection system  100  can modify firing event sequence  108  of each actuator in a group of actuators ( 802 ). In some examples, the modification of firing event sequence  108  can be based in part on the determination that fluid ejection system  100  is operating in the service mode. 
     Controller  102  can modify firing event sequence  108  associated with a normal mode of operations, for a more efficient fluid (e.g., shipping fluid) purge. In some examples, controller  102  can modify firing event sequence  108  based on an actuator type of each actuator. Examples of actuator types include a recirculation type actuator and a fluid ejector type actuator. The recirculation type actuator does not include an orifice and may recirculate or pump fluid within one or more chambers of the recirculation type actuator when fired. The fluid ejector type actuator includes an orifice and when fired, can eject drops of fluid (e.g., shipping fluid or ink) from the chamber through the orifice. In some examples, the fluid ejector type actuator can be a HDW (high drop weight) fluid ejector type actuator. In other examples, the fluid ejector type actuator can be a LDW (low drop weight) fluid ejector type actuator. The HDW fluid ejector type includes an orifice with a larger orifice to eject higher weighted or larger sized fluid drops than the LDW fluid ejector type actuator. In some examples, the recirculation type actuator can be operatively connected to an ejector type actuator with a fluidic channel. In such examples, the recirculation type actuator may recirculate or pump fluid within one or more chambers of the proximate ejector actuator(s) when fired. 
     In other examples, controller  102  can modify firing event sequence  108  based on a column and/or actuator group of fluid ejection die  104  each actuator is associated with. In yet other examples, controller  102  can modify firing event sequence  108  based on an actuator type and a column and/or actuator group of fluid ejection die  104  each actuator is associated with. 
     Fluid ejection system  100  can utilize the modified firing event sequence  108  to purge fluid (e.g., shipping fluid) from fluid ejection die  104 . For example controller  102  can transmit the modified firing event sequence  108  to fluid ejection die  104  to purge fluid from fluid ejection die  104 . In response to fluid ejection die  104  receiving firing event sequence  108 , fluid ejection die  104  can control actuator(s)  106  to fire/purge fluid. 
       FIG. 8B  illustrates an example methods for purging fluid from a fluid ejection system based on actuator type. In some examples, similar to the principles as previously described, fluid ejection system  100  can determine an operational mode ( 804 ). In response to fluid ejection system  100  determining fluid ejection system  100  is in a service mode, fluid ejection system  100  can determine an actuator type each actuator is associated with ( 806 ). For example, controller  102  can determine the actuator type associated with the address or identifier of each actuator in a group of actuators (e.g., fluid ejector type actuator, a recirculation type actuator, HDW fluid ejector type actuator or a LDW fluid ejector type actuator). 
     Additionally, in response to fluid ejection system  100  determining fluid ejection system  100  is in a service mode, fluid ejection system  100  can modify firing event sequence  108  of each actuator in a group of actuators, based on the actuator type of each actuator ( 808 ). For example, after controller  102  determines the actuator type associated with the address or identifier of each actuator, controller  102  can modify firing event sequence  108  based on the actuator type associated with the address or identifier of each actuator. 
     In some examples, fluid ejection system  100  undergoing fluid purge (service mode), may include a fluid ejector type actuator and a recirculation type actuator. As noted above, recirculation type actuators do not eject fluid and if fired would not help purge fluid and waste resources of the fluid ejection system. In such examples, fluid ejection system  100  can modify firing event sequence  108  to make fluid purge more efficient by removing data firing packets addressed to recirculation actuators. With reference to  FIGS. 5A and 5B , for example, controller  102  can determine firing data packets that include addresses to recirculation type actuators. As such, controller  102  can remove firing data packets addressed to LDW fluid ejector type actuators. The same principles can be applied to fluid ejection system  100  undergoing going fluid purge (service mode) and including HDW fluid ejector type actuators and LDW fluid ejector type actuator. 
     Moreover, in some examples, resource limitations (e.g., fluidic limitations, data rate limitations, and power supply and power parasitic limitations) of fluid ejection system  100  can be taken into account when modifying firing event sequence  108 . For example with reference to  FIGS. 5A and 5B , controller  102  can remove firing data packets all addressed to recirculation type actuators (e.g., FPG  502 , FPG  506 , FPG  510 , and FPG  514 ) because recirculation type actuators do not further purging fluid from fluid ejection system  100 . As such, controller  102  can add (and has added) additional firing data packets addressed to fluid ejector type actuators (e.g., FPG  500 , FPG  504 , FPG  508  and FPG  512 ) to firing event sequence  516  to maximize data rates given the previously described data rate limitations. In another example, with reference to  FIGS. 7A and 7B , controller  102  can remove firing data packets all addressed to LDW fluid ejector type actuators (e.g., FPG  702 , FPG  706 , FPG  710 , and FPG  714 ) because LDW fluid ejector type actuators are not as efficient in purging fluid from fluid ejection system  100  as HDW fluid ejector type actuators. As such, controller  102  can add (and has added) additional firing data packets addressed to HDW fluid ejector type actuators (e.g., FPG  700 , FPG  704 , FPG  708  and FPG  712 ) to firing event sequence  716  to maximize data rates given the previously described data rate limitations. 
       FIG. 8C  illustrates an example method for purging fluid from a fluid ejection system based on a column and/or actuator group of a fluid ejection die each actuator is associated with. Similar to the example method illustrated in  FIG. 8B , in some examples fluid ejection system  100  can determine an operational mode ( 810 ). In response to fluid ejection system  100  determining fluid ejection system  100  is in a service mode, fluid ejection system  100  can determine a column identifier and/or an actuator group identifier of fluid ejection die  104  each actuator  106  of an actuator group is associated with ( 812 ). Additionally, in response to fluid ejection system  100  determining fluid ejection system  100  is in a service mode, fluid ejection system  100  can modify firing event sequence  108  of each actuator in a group of actuators, based on the column identifier and/or actuator group identifier each actuator  106  is associated with ( 814 ). 
       FIG. 8D  illustrates an example method for purging fluid from a fluid ejection system based on an actuator type and a column and/or actuator group of a fluid ejection die each actuator is associated with. Similar to the example method illustrated in  FIGS. 8B and 8C , in some examples fluid ejection system  100  can determine an operational mode ( 816 ). Additionally similar to the example method illustrated in  FIG. 8B , fluid ejection system  100  can determine an actuator type each actuator is associated with ( 818 ). Additionally, similar to the example method illustrated in  FIG. 8C  fluid ejection system  100  can determine a column identifier and/or actuator group identifier of fluid ejection die  104  each actuator  106  of an actuator group is associated with ( 820 ). Moreover, in response to fluid ejection system  100  determining fluid ejection system  100  is in a service mode, fluid ejection system  100  can modify firing event sequence  108  of each actuator in a group of actuators, based on the actuator type and the column identifier and/or actuator group identifier each actuator  106  is associated with ( 822 ). 
     In some examples, fluid ejection system  100  undergoing fluid purge (e.g., service mode), may include HDW fluid ejector type actuators and LDW fluid ejector type actuators. As noted above, utilizing HDW fluid ejector type actuators can consume more available resources of fluid ejection system  100  than utilizing LDW fluid ejector type actuators. In some examples, fluid ejection system  100  utilizing firing event sequence  108  with only firing data packets addressed to HDW fluid ejector type actuators (e.g., firing event sequence  716  of  FIG. 7B ), can result in consumption of a higher peak power than firing event sequence  108  with only firing data packets addressed to LDW fluid ejector type actuators or to LDW fluid ejector type actuators and HDW fluid ejector type actuators. In such examples, controller  102  can add to the firing sequence  108  of only firing data packets addressed to HDW fluid ejector type actuators, addresses of LDW fluid ejector type actuators. With reference to  FIGS. 7B and 7C , for example, controller  102  can determine the firing data packets are addressed to HDW fluid ejector type actuators. As such, controller  102  can add to the firing data packets addresses of LDW fluid ejector type actuators. 
     Moreover, in such examples, controller  102  can further specify in the firing data packet of the firing event sequence, a column or a actuator group specific HDW or LDW fluid ejector type actuator. For example, with reference to  FIG. 7C , each firing data packet of firing event sequence  716  can include the column identifier or actuator group identifier the HDW fluid ejector type actuator and LDW fluid ejector type actuator are associated with. For instance with further reference to  FIG. 6  and FPG  700  of  FIG. 7 , FPG  700  can include specific column identifiers associated with the A 0  address of HDW fluid ejector type actuator and A 1  address of LDW fluid ejector type actuator (e.g., the column identifier of the right column of actuators illustrated in  FIG. 6 ). In another instance, again referring to  FIG. 6  and FPG  700  of  FIG. 7 , FPG  700  can include the specific actuator group identifier associated with the A 0  address of HDW fluid ejector type actuator and the A 1  address of LDW fluid ejector type actuator (e.g., actuator group  602  and actuator group  604  illustrated in  FIG. 6 , respectively). 
     In other examples, at the end of the service mode, fluid ejection system  100  may still have some residual unpurged fluid (e.g., shipping fluid) in fluid ejection die  102 . In such examples, controller  102  can determine the drop rate of each actuator  106  (e.g., how much fluid is ejected out of each actuator  106  per firing event) and how much fluid was originally installed in fluid ejection system  100 . Taken together, controller  102  can determine how much residual unpurged fluid is still in fluid ejection system  100  at the end of the service mode. Additionally, controller  102  can determine the number of firing data packets or firing event sequences should be transmitted to fluid ejection die  106  to ensure total purging of fluid. Such a determination can be based on the amount of residual unpurged fluid controller  102  earlier determined and the drop rate of actuators(s)  106 . Moreover, such determinations can be made after controller  102  determines fluid ejection system  100  is at the end of the service mode or is still currently operating in a service mode. 
     Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.