Patent Publication Number: US-2022227138-A1

Title: Printers with refillable printing fluid reservoirs

Description:
BACKGROUND 
     A printer is a device that applies a material (e.g., ink, toner, dye, agent, etc.) to a medium (e.g., paper). Printers can vary in type, and examples include laser printers, inkjet printers, solid ink printers, thermal printers, dye-sublimation printers, 3D printers, and others. The substance the printer applies to the medium is consumed during printing and therefore typically requires replenishment. In some printer devices replenishment is accomplished by adding additional material to supplied from an external bottle. The material is generally added by opening the printer to access an internal reservoir, coupling the bottle, flowing material from the bottle to the reservoir via gravity, and thereafter uncoupling the bottle and closing the printer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description references the drawings, in which: 
         FIG. 1  is a schematic view of a printing system constructed in accordance with the present disclosure according to an example, showing the printing system using a printing fluid pump to draw printing fluid from a printing fluid reservoir and communicate the printing fluid to a print head assembly; 
         FIG. 2  is a schematic view of the printing system of  FIG. 1 , showing the printing system refilling the printing fluid reservoir by drawing printing fluid from a printing fluid refill bottle and communicate the printing fluid to the printing fluid reservoir with the printing fluid pump; 
         FIG. 3  is a schematic view of the printing system of  FIG. 1 , showing the printing system recirculating printing fluid from the printing fluid reservoir through a supply conduit and charging conduit using the printing fluid pump; 
         FIG. 4  is a schematic view of the printing system of  FIG. 1 , showing the printing system returning printing fluid to the printing fluid refill bottle using the printing fluid pump when the printing fluid reservoir is overfilled; 
         FIG. 5  is a schematic view of the printing system of  FIG. 1 , showing the printing system purging excess printing fluid in the printing fluid reservoir through the print head assembly using the printing fluid pump; and 
         FIG. 6  is a block diagram of a method of refilling a printing fluid reservoir in a printing system according to a non-limiting example of the method. 
     
    
    
     DETAILED DESCRIPTION 
     The systems and methods described herein provide printing fluid refilling for the printing fluid reservoir within a printing system from a charging port located on the exterior of the printing system housing. The charging port is connected to the printing fluid reservoir by a charging conduit, which fluidly couples the charging port to a printing fluid pump and allows the printing fluid reservoir to be positioned within the interior of the printing system independent of the position of the charging port, simplifying the arrangement of the printing system. In certain examples a printing fluid pump is employed to draw printing fluid from a printing fluid refill bottle, reducing the amount of time required to add additional printing fluid to the printing system. In accordance with certain examples the charging conduit is connected to the printing system supply conduit between the printing fluid reservoir and the printing fluid pump, allowing the printing fluid pump employed to communicate printing fluid to the print head assembly to also drive refill printing fluid from the printing fluid refill bottle into the printing fluid reservoir. It is also contemplated that, in certain examples, the printing fluid pump can be operated at a different speed during refilling than during printing to limit the time required for refilling the printing fluid reservoir. 
     In traditional printing systems, such as a continuous printing fluid system, printing fluid consumed during printing is periodically replaced. Printing fluid refilling generally requires that the printing fluid reservoir be accessed by opening the printing system and coupling a printing fluid refill bottle to the printing fluid reservoir. Once the printing fluid refill bottle is coupled to the printing fluid reservoir, refill printing fluid is transferred from the printing fluid refill bottle to the printing fluid reservoir, generally using gravity to flow the refill printing fluid from the refill printing fluid bottle and into the printing fluid reservoir through a fill port on, e.g., defined by and local to, the printing fluid reservoir. The printing fluid refill bottle is thereafter uncoupled from the printing fluid reservoir, the housing of the printing system closed, and the printing system returned to operation. While generally acceptable for its intended purpose, printing fluid refilling in such printing systems can be relatively slow. Further, the need to position the printing fluid reservoir such that the fill port is accessible to the user can limit the size and/or positioning of the printing fluid reservoir within the printing system. 
     The present systems and techniques overcome these shortcomings by providing a bottle seat located on the exterior of the printing system and remote from the printing fluid reservoir. Arranging the bottle seat remotely with respect to the printing fluid reservoir eliminates the need for the user to access the interior of the printing system to refill the printing fluid reservoir. Arranging the bottle seat remotely also removes the need to position the printing fluid reservoir in a location where the user can access the printing fluid reservoir for refilling. 
     An example of an additional benefit of the bottle seat is the ability for connection of the printing fluid pump between the bottle seat and the printing fluid reservoir. Placement of the printing fluid pump between the bottle seat and the printing fluid reservoir allows the printing fluid pump to draw the printing fluid from an printing fluid refill bottle seated on the bottle seat, increasing the rate at which printing fluid is added to the printing fluid reservoir and reducing the time required for refilling the printing fluid reservoir when gravity is the motive force. Further, it is contemplated that the speed of the printing fluid pump can be increased relative to that of printing, further reducing the time required to refill the printing fluid reservoir. Another example benefit is the capability to fluidly connect the printing fluid reservoir to the bottle seat. Fluid connection of the printing fluid reservoir to the bottle seat allows the printing fluid pump to return excess printing fluid from the printing fluid reservoir to the printing fluid refill bottle, reducing (or eliminating entirely) the need for the user or the controller  122  to monitor the printing fluid refill process to prevent overfilling the printing fluid reservoir. 
       FIGS. 1-5  include components, modules, engines, etc. according to various examples as described herein. In different examples, more, fewer, and/or other components, modules, engines, arrangements of components/modules/engines, etc. can be used according to the teachings described herein. In addition, the components, modules, engines, etc. described herein are implemented as software modules executing machine-readable instructions, hardware modules, or special-purpose hardware (e.g., application specific hardware, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), embedded controllers, hardwired circuitry, etc.), or some combination of these. 
     Referring to  FIG. 1 , an example printing system  100  is shown. The printing system  100  includes a housing  102 , a printing fluid reservoir  104 , a printing fluid level sensor  106 , and a bottle seat  108 . The printing system  100  also includes a bottle-detect sensor  110 , a printing fluid distribution network  112 , a printing fluid pump  114 , and a pressure control device  116 . The printing system  100  additionally includes a printing fluid-air separator  118 , a print head assembly  120 , and a controller  122 . 
     The housing  102  supports the bottle seat  108  and has an interior  124 . The bottle-detect sensor  110 , e.g., a switch arranged to provide a voltage when triggered, is arranged proximate the bottle seat  108  to detect the presence or absence of a printing fluid refill bottle  10  (shown in  FIG. 2 ) at the bottle seat  108 . The printing fluid reservoir  104 , the printing fluid distribution network  112 , and the print head assembly  120  are arranged within the interior  124  of the housing  102 . The printing fluid pump  114 , the pressure control device  116 , the printing fluid-air separator  118 , and the controller  122  are also arranged within the interior  124  of the housing  102 . 
     The printing fluid reservoir  104  has a reservoir body  126  with an interior  128 . The reservoir body  126  defines a reservoir body vent orifice  130 , a reservoir body inlet orifice  132 , and a reservoir body outlet orifice  134  to provide fluid communication between the interior  128  of the reservoir body  126  and the printing fluid distribution network  112 . The printing fluid distribution network  112  in turn provides fluid communication between the printing fluid reservoir  104  and the print head assembly  120 . The printing fluid distribution network  112  also provides fluid communication between the printing fluid reservoir  104  and the bottle seat  108 . 
     A charge of printing fluid  12 , e.g., ink, is disposed within the interior  128  of the reservoir body  126 . The charge of printing fluid  12  includes liquid printing fluid  14  with a printing fluid surface  16 . The printing fluid surface  16  is disposed within the interior  128  of the reservoir body  126  and defines an ullage space  18  between the printing fluid surface  16  and an interior surface  136  of the reservoir body  126 . As shown in  FIG. 1  a printing fluid level sensor  106  is in communication with the interior  128  of the reservoir body  126 , the printing fluid level sensor  106  arranged to communicate a signal  20  indicative of the amount of the liquid printing fluid  14 , e.g., by reporting the location of printing fluid surface  16 . 
     The bottle seat  108  is fixed to an exterior  138  of the housing  102 , is configured to provide fluid communication with the interior  128  of the reservoir body  126  and cooperates with a closure  140 . In this respect the bottle seat  108  has a seat body  142 . 
     The seat body  142  defines a vent port  144  and a charging port  146 . The vent port  144  is co-located with the charging port  146  at the bottle seat  108  and is fluidly coupled to the interior  128  of the reservoir body  126  by the printing fluid distribution network  112 . The charging port  146  is also fluidly coupled to the interior  128  of the reservoir body  126 . The closure  140  is movable between a first position A (e.g., a closed position), wherein the closure  140  abuts the seat body  142  and fluidly separates the charging port  146  from the external environment  22 , and a second position B (e.g., an open position), wherein the closure  140  is spaced apart from the seat body  142  and the charging port  146  is in fluid communication with the external environment  22 . It is contemplated that the vent port  144  be in fluid communication with the external environment  22  when the closure  140  is in both the first position A and the second position B. 
     The printing fluid distribution network  112  fluidly couples the printing fluid reservoir  104  to the bottle seat  108  and the print head assembly  120 . In this respect the printing fluid distribution network  112  includes a vent conduit  148 , a supply conduit  150 , and a charging conduit  152 . The printing fluid distribution network  112  also includes a return conduit  154 , a print head assembly conduit  156 , a suction-side union  158 , and a pressure-side union  160 . 
     The vent conduit  148  is arranged within the interior  124  of the housing  102  and fluidly couples the reservoir body  126  to the bottle seat  108 . More specifically, the vent conduit  148  is connected on a first end to the reservoir body  126  at the reservoir body vent orifice  130 , and to the vent port  144  defined by the bottle seat  108  on a second end of the vent conduit  148 . 
     The supply conduit  150  is also arranged within the interior  124  of the housing  102  and fluidly couples the reservoir body  126  to the printing fluid pump  114 . More specifically, the supply conduit  150  is connected at a first end to the reservoir body  126  at the reservoir body outlet orifice  134 , and to the printing fluid pump  114  at a second end of the supply conduit  150 . The suction-side union  158  is arranged along a length of the supply conduit  150  between the reservoir body outlet orifice  134  and the printing fluid pump  114 . The suction-side union  158  in turn fluidly couples the charging port  146  defined by the seat body  142  to printing fluid pump  114  through the charging conduit  152 . The charging conduit  152  fluidly couples the charging port  146  to the printing fluid reservoir  104  to convey refill printing fluid received at the charging port  146  through the interior  124  of the housing  102  and to the printing fluid reservoir  104 . 
     The return conduit  154  is additionally arranged within the interior  124  of the housing  102  and fluidly couples the printing fluid pump  114  to the reservoir body  126 . More specifically, the return conduit  154  is connected at a first end to the printing fluid pump  114 , and to the reservoir body inlet orifice  132  of the reservoir body  126  at an opposite second end of the return conduit  154 . The pressure-side union  160  is arranged along a length of the return conduit  154  between the reservoir body inlet orifice  132  and the printing fluid pump  114 , and the pressure control device  116  is arranged along the length of the return conduit  154  between the pressure-side union  160  and the reservoir body inlet orifice  132 . The pressure-side union  160  in turn fluidly couples the print head assembly  120  to the printing fluid pump  114  through the pressure-side union  160  and a portion of the return conduit  154  extending between the pressure-side union  160  and the printing fluid pump  114 . 
     The controller  122  includes a processor  162 , a memory  164 , a device interface  166 , and a user interface  168 . The device interface  166  operably connects the processor  162  to the printing fluid pump  114  and the print head assembly  120 , e.g., via a wired or wireless link  172 . The device interface  166  also places the processor  162  in communication with the bottle-detect sensor  110  and the printing fluid level sensor  106 . Communication with the processor  162  in turn enables the printing fluid level sensor  106  to provide the signal  20  indicative of the amount of printing fluid  12  disposed within the interior  128  of the reservoir body  126  to the processor  162 . Communication with the processor  162  also enables the bottle-detect sensor  110  to provide a bottle-present signal  36  (shown in  FIG. 2 ) indicative of presence/absence of the printing fluid refill bottle  10  (shown in  FIG. 2 ) at the bottle seat  108 . In this respect the bottle-detect sensor  110  is operably associated with the bottle seat  108 , i.e., seating a refill bottle on the bottle seat  108  cause the bottle-detect sensor  110  to issue the bottle-present signal  36  indicating presence of the printing fluid refill bottle. 
     The processor  162  is disposed in communication with the user interface  168 , the user interface  168  in turn configured to communicate a user input  24  to processor  162 . The memory  164  in turn has a plurality of program modules  170  recorded on the memory  164  that, when read by the processor  162 , cause the processor  162  to execute certain operations. Among the operations are those of a method  200  (shown in  FIG. 6 ) of refilling a printing fluid reservoir, e.g., the printing fluid reservoir  104 , as will be described. It is contemplated that the processor  162  can be implemented with circuitry, software, or a combination of circuitry and software. 
     As shown in  FIG. 1 , during printing, the controller  122  causes the printing fluid pump  114  to communicate a printing fluid flow  26  to the print head assembly  120 , which in turn deposits printing fluid  28  from the printing fluid flow  26  on a substrate  30 , e.g., a media sheet or a printed article. In this respect the controller drives the printing fluid pump  114  at a first pump speed  32 . The printing fluid pump  114  in turn pulls the printing fluid flow  26  from the reservoir body outlet orifice  134 , through the supply conduit  150 , and to the printing fluid pump  114 . Once at the printing fluid pump  114  the printing fluid pump drives the printing fluid flow  26  (or a portion thereof) to the print head assembly  120 , which deposits the printing fluid  28  on the substrate  30 . 
     As will be appreciated art in view of the present disclosure, the volume of liquid printing fluid  14  within the printing fluid reservoir  104  decreases during printing. Since the volume decrease can increase the work necessary to communicate the printing fluid flow  26  to the print head assembly  120  the vent conduit  148  provides fluid communication between the external environment  22  and the ullage space  18  within the interior  128  of the reservoir body  126 . Fluid communication between the external environment  22  and the ullage space  18  in turn maintains pressure therein substantially equivalent to ambient pressure in the external environment  22 , allowing the printing fluid pump  114  to be relatively small and/or compact. 
     As also shown in  FIG. 1 , the closure  140  is in the first position A. As such no fluid flows between suction-side union  158  and the charging port  146 . In certain examples the closure  140  can be in fluid-tight engagement with the seat body  142 , limiting (or eliminating entirely) the need to remove entrained air from the printing fluid flow  26 . In accordance with certain examples the closure  140  is loosely fit to the seat body  142 , simplifying the manufacturing of the seat body  142  and/or the closure  140 —air ingested and entrained in the printing fluid flow  26  being removed by the printing fluid-air separator  118  (which is optional). 
     With reference to  FIG. 2 , the printing system  100  is shown during refilling. To refill the printing fluid reservoir  104  the closure  140  is moved to the second position B and the printing fluid refill bottle  10  seated on the bottle seat  108 . Seating the printing fluid refill bottle  10  on the bottle seat  108  fluidly couples the printing fluid refill bottle  10  to the printing fluid reservoir  104 . More specifically, the seating the printing fluid refill bottle  10  on the bottle seat  108  places an interior  34  of the printing fluid refill bottle  10  in fluid communication with the interior  128  of the reservoir body  126  through both the vent port  144  and the charging port  146 . The vent port  144  in turn fluidly couples the printing fluid refill bottle  10  to the interior  128  of the reservoir body  126  through the vent conduit  148  and the reservoir body vent orifice  130 . The charging port  146  also fluidly couples the printing fluid refill bottle  10  to the printing fluid pump  114  through the charging conduit  152 , the pressure-side union  160 , and a portion of the supply conduit  150  connecting the pressure-side union  160  to the printing fluid pump  114 . 
     Seating the printing fluid refill bottle  10  on the bottle seat  108  also triggers the bottle-detect sensor  110 . In this respect the bottle-detect sensor  110  generates a bottle-present signal  36  indicating presence of the printing fluid refill bottle  10  at the bottle seat  108 . The wired or wireless printing fluid  172  conveys the bottle-present signal  36  to the controller  122 , which responds by turning on the printing fluid pump  114  by issuing a speed command to the printing fluid pump  114 . Once turned on by the controller  122  in response to the bottle-present signal  36 , the printing fluid pump  114  drives a flow of refill printing fluid  50  through the printing fluid pump  114  to the interior  128  of the reservoir body  126 . More specifically, the printing fluid pump  114  drives the flow of refill printing fluid  50  through the return conduit  154  and the pressure control device  116 , and therethrough into the printing fluid reservoir  104 . In certain examples movement of the closure  140  to the second position B causes the print head assembly  120  to cease printing, e.g., upon completion of the print job in process at the time the closure  140  is moved to the second position B. 
     It is contemplated that the controller  122  causes the printing fluid pump to operate at a second printing fluid pump speed  38 , the second printing fluid pump speed  38  being enough to cause the pressure control device  116  to open. In accordance with certain examples, the second printing fluid pump speed  38  can be greater than that of the first pump speed  32  (shown in  FIG. 1 ). In certain examples the second printing fluid pump speed  38  is about twice the speed of the first pump speed  32 . As will be appreciated in view of the present disclosure, air displaced from the interior  128  of the reservoir body  126  flows from the ullage space  18  to the interior of the printing fluid refill bottle  10  through the vent conduit  148  and the vent port  144 , limiting the amount of work required by the printing fluid pump  114  to drive the flow of refill printing fluid  50  to the printing fluid reservoir  104  while retaining sealing of the printing system  100  during refilling. 
     With reference to  FIG. 3 , the printing system  100  is shown recirculating the liquid printing fluid  14  from within the interior  128  of the reservoir body  126  through the printing fluid pump  114 . Recirculation of the liquid printing fluid  14  occurs when no refill bottle, e.g., the printing fluid refill bottle  10  (shown in  FIG. 2 ) is present at the bottle seat  108  and the print head assembly  120  is inactive. More specifically, when no printing fluid refill bottle  10  is present at the bottle seat  108  the bottle-detect sensor  110  provides an indication that no bottle is present at the bottle seat  108 . In certain examples the indication is provided by absence of the bottle-present signal  36  (shown in  FIG. 2 ). In accordance with certain examples the indication is provided by a signal  40  generated by the bottle-detect sensor  110  and communicated to the controller  122  by the wired or wireless printing fluid  172 . It is also contemplated that the indication can be provided by moving the closure  140  to the first position A. 
     When the controller  122  receives indication (or discerns) that no refill bottle is present at the bottle seat  108 , and the print head assembly  120  is idle (i.e., no printing is occurring), the controller  122  recirculates the liquid printing fluid  14  through a portion of the printing fluid distribution network  112 . In this respect the controller  122  causes the printing fluid pump  114  to draw a recirculation printing fluid flow  42  from the interior  128  of the reservoir body  126  through the supply conduit  150  and the pressure-side union  160 , and thereafter to the interior  128  of the reservoir body  126  through the return conduit  154  and the pressure control device  116 . 
     It is contemplated that, during recirculation, the closure  140  provides sealing enough to limit (or eliminate entirely) ingestion of air from the external environment  22  through the charging port  146 . It is also contemplated that, during recirculation, the print head assembly  120  fluidly isolates the pressure-side union  160  and the print head assembly conduit  156  from the external environment  22  such that substantially none of the recirculation printing fluid flow  42  enters the print head assembly conduit  156 . This allows the printing system  100  to retain the liquid printing fluid  14  in a ready-to-use state while limiting printing fluid communication within portions of the printing fluid distribution network  112  beyond the suction-side union  158  and the pressure-side union  160 . 
     With reference to  FIGS. 4 and 5 , the printing system  100  is shown correcting for overfill via return of printing fluid to the printing fluid refill bottle  10  and via purge of the vent conduit  148  of residual printing fluid, respectively. As will be appreciated in view of the present disclosure, some printing systems allow the printing system printing fluid reservoir to overfill, potentially causing the printing fluid reservoir orifice to become submerged. To correct for overfill the printing system  100  is configured to return printing fluid to the printing fluid refill bottle  10  via a return printing fluid flow  44  (shown in  FIG. 4 ) when the printing fluid refill bottle  10  is seated on the bottle seat  108 , and is additionally configured to purge residual printing fluid from vent conduit  148  via a print job printing fluid flow  48  (shown in  FIG. 5 ) when no printing fluid refill bottle is present at the bottle seat  108 . 
     Referring to  FIG. 4 , overfill correction by return of printing fluid to the printing fluid refill bottle  10  is shown. Return of printing fluid from the printing fluid reservoir  104  begins when the printing fluid surface  16  within the printing fluid reservoir  104  rises above the reservoir body vent orifice  130 . Once above the reservoir body vent orifice  130  the printing fluid surface  16  fluidly separates the ullage space  18  (shown in  FIG. 1 ) from the reservoir body vent orifice  130 . Fluid separation of the ullage space  18  from the reservoir body vent orifice  130  causes printing fluid thereafter introduced into the printing fluid reservoir  104  by operation of the printing fluid pump  114  to increase pressure within the ullage space  18 . Pressure increase within the ullage space  18  in turn urges printing fluid from within the printing fluid reservoir  104  through the reservoir body vent orifice  130 , through the vent conduit  148 , and to the printing fluid refill bottle  10  via the vent port  144  as the return printing fluid flow  44 . As will be appreciated in view of the present disclosure, the return printing fluid flow  44  generated by the pressure imbalance limits the amount of printing fluid that can be added to the printing fluid reservoir  104 —reducing (or eliminating entirely) the possibility of overfilling of the printing fluid reservoir  104 . This allows a user, for example, to seat a printing fluid refill bottle at the bottle seat  108  having more printing fluid therein than the printing fluid reservoir  104  may be in a condition receive. In certain examples the effective flow area of the vent port  144  in relation to the charging port  146 , in conjunction with the speed of the printing fluid pump  114 , determines the height of the printing fluid surface  16  required to initiate return of printing fluid from the printing fluid reservoir  104  to the printing fluid refill bottle  10 . 
     Referring to  FIG. 5 , vent tube purging is shown. When the bottle-detect sensor  110  indicates that the printing fluid refill bottle  10  (shown in  FIG. 2 ) has been removed from the bottle seat  108  the controller  122  turns off the printing fluid pump  114 . Turning off the printing fluid pump  114  ceases communication of printing fluid through the vent conduit  148 . In some circumstances residual printing fluid can remain within the vent conduit  148 , e.g., when the reservoir body vent orifice  130  is submerged within the printing fluid  12  contained with the interior  128  of the printing fluid reservoir  104 , subsequent to the printing fluid reservoir  104  becoming overfilled. In such event it is contemplated that the printing system  100  purge the vent conduit  148  during subsequent operation of the printing system  100 . 
     Specifically, upon receipt of a print job, the controller  122  turns on the printing fluid pump  114  and the print head assembly  120 . Turning on the print head assembly  120  causes the print head assembly  120  to issue a print job printing fluid flow  48 , e.g., to the substrate  30  (shown in  FIG. 1 ), associated with the print job. Turning on the printing fluid pump  114  causes the printing fluid pump  114  to draw printing fluid from the reservoir body outlet orifice  134  to form the print job printing fluid flow  48 , which the printing fluid pump  114  draw through the supply conduit  150  and pushes to the print head assembly  120  through the print head assembly conduit  156 . 
     As printing fluid is drawn from the printing fluid reservoir  104  the printing fluid surface  16  drops, shown in  FIG. 5  with a downward arrow extending from the printing fluid surface  16 . Drop in the printing fluid surface  16  in turn reduces pressure within the ullage space  18  (shown in  FIG. 1 ) defined within the interior  128  of the printing fluid reservoir  104  and the printing fluid surface  16  relative to pressure in the external environment  22 . The pressure differential between the external environment  22  and the ullage space  18  urges residual printing fluid inhabiting the vent conduit  148  into the interior  128  of the printing fluid reservoir  104  through the reservoir body vent orifice  130  as a printing fluid purge flow  52 . It is contemplated that the printing fluid purge flow  52  continue until such time as the vent conduit is clear, at which point pressure within the ullage space  18  substantially equalizes with that of the external environment  22 —the vent conduit  148  at that point being substantially purged of residual printing fluid. 
     With reference to  FIG. 6 , the method  200  of adding printing fluid to a printing system, e.g., the printing system  100  (shown in  FIG. 1 ), is shown. As shown with box  210 , the method  200  includes consuming printing fluid from a printing fluid reservoir, e.g., the printing fluid reservoir  104  (shown in  FIG. 1 ), by printing. It is contemplated that the printing fluid be consumed by depositing the printing fluid on a medium, e.g., the substrate  30  (shown in  FIG. 1 ), using a printing fluid printing system. 
     As shown with box  222 , a determination is made as to whether a printing fluid refill bottle, e.g., the printing fluid refill bottle  10  (shown in  FIG. 2 ), is seated on a bottle seat of the printing system, e.g., the bottle seat  108  (shown in  FIG. 1 ). The determination can be made, for example, using a signal provided by a bottle-detect sensor, e.g., the bottle-detect sensor  110  (shown in  FIG. 1 ). 
     When no printing fluid refill bottle is detected as being present at the bottle seat a printing fluid pump of the printing system, e.g., the printing fluid pump  114  (shown in  FIG. 1 ), is operated (i.e. driven) at a first pumping speed, e.g., the first pump speed  32  (shown in  FIG. 1 ). It is contemplated that the first pumping speed be selected such that the printing system continue to consume printing fluid during application of the printing fluid on the substrate(s), as shown with arrow  232 . 
     When the printing fluid refill bottle is detected as present at the bottle seat the printing fluid pump is driven at a second pumping speed, as shown with box  240 . With the printing fluid pump operating at the second pumping speed the printing system receives refill printing fluid at a charging port, e.g., the charging port  146  (shown in  FIG. 1 ), as shown with box  250 . The refill printing fluid is conveyed through an interior of a housing of the printing system, e.g., the interior  124  (shown in  FIG. 1 ) of the housing  102  (shown in  FIG. 1 ) and communicated to the printing fluid reservoir, as shown with box  262 . 
     It is contemplated that the charging continues until the signal  20  from the printing fluid level sensor  106  indicates that the printing fluid reservoir has reached a predetermined fill level, the printing fluid refill bottle is empty, and/or that the printing fluid refill bottle has been removed from the bottle seat, as shown with arrow  270 . Printing thereafter resumes, as shown with box  210 . It is also contemplated that, in event that the printing fluid reservoir becomes overfilled, that the overfill condition can be corrected. For example, printing fluid can be returned to a printing fluid refill bottle, as shown with box  262 . Alternatively (or additionally), printing fluid can be purged from the printing system with a purge flow issued from a print engine, e.g., the print head assembly  120  (shown in  FIG. 2 ), as shown with box  264 . 
     The processes and operations shown in  FIG. 6  are illustrative of an example of a method in accordance with the present disclosure. As will be appreciated in view of the present disclosure, additional processes and/or operations may be added, removed, modified, and/or rearranged without departing from the scope of the present disclosure. 
     It should be emphasized that the above-described examples are merely possible examples of implementations and set forth for a clear understanding of the present disclosure. Many variations and modifications may be made to the above-described examples without departing substantially from the principles of the present disclosure. Further, the scope of the present disclosure is intended to cover any and all appropriate combinations and sub-combinations of all elements, features, and aspects discussed above. All such appropriate modifications and variations are intended to be included within the scope of the present disclosure, and all possible claims to individual aspects or combinations of elements or processes are intended to be supported by the present disclosure.