Patent Publication Number: US-11376857-B2

Title: Input/output (I/O) design of a printhead allowing for daisy-chaining

Description:
RELATED APPLICATIONS 
     This non-provisional patent application is a continuation of U.S. patent application Ser. No. 16/351,147 filed on Mar. 12, 2019, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The following disclosure relates to the field of image formation, and in particular, to printheads and the use of printheads. 
     BACKGROUND 
     Image formation is a procedure whereby a digital image is recreated on a medium by propelling droplets of ink or another type of print fluid onto a medium, such as paper, plastic, a substrate for 3D printing, etc. Image formation is commonly employed in apparatuses, such as printers (e.g., inkjet printer), facsimile machines, copying machines, plotting machines, multifunction peripherals, etc. The core of a typical jetting apparatus or image forming apparatus is one or more liquid-droplet ejection heads (referred to generally herein as “printheads”) having nozzles that discharge liquid droplets, a mechanism for moving the printhead and/or the medium in relation to one another, and a controller that controls how liquid is discharged from the individual nozzles of the printhead onto the medium in the form of pixels. 
     A typical printhead includes a plurality of nozzles aligned in one or more rows along a discharge surface of the printhead. Each nozzle is part of a “jetting channel”, which includes the nozzle, a pressure chamber, and a diaphragm that is driven by an actuator, such as a piezoelectric actuator. A printhead also includes a drive circuit that controls when each individual jetting channel fires based on image data. To jet from a jetting channel, the drive circuit provides a jetting pulse to the actuator, which causes the actuator to deform a wall of the pressure chamber via the diaphragm. The deformation of the pressure chamber creates pressure waves within the pressure chamber that eject a droplet of print fluid (e.g., ink) out of the nozzle. 
     Opposite the discharge surface of the printhead is the Input/Output (I/O) surface, where a print fluid is supplied to the printhead, or conveyed out of the printhead (such as with a flow-through head). The I/O surface includes I/O ports that typically connected to a reservoir or the like via a hose. Unfortunately, it may be cumbersome to connect the printheads to the reservoirs with the present I/O design. 
     SUMMARY 
     Embodiments described herein comprise a printhead having one or more I/O ports situated on one side or both sides. The printhead also has one or more manifolds that fluidly couple the I/O ports on one side of the printhead, or fluidly couple the I/O ports on opposing sides of the printhead. Based on the configuration of the I/O ports and manifolds, printheads may be daisy-chained together so that a print fluid flows from one printhead to another in a supply chain. Thus, it is not necessary to run a hose to each individual printhead, making set up and operation more efficient. 
     One embodiment comprises a printhead that includes a plurality of jetting channels having nozzles on a bottom surface configured to jet a print fluid, and longitudinal sides disposed between the bottom surface and a top surface. The printhead further includes I/O ports disposed on one or more of the longitudinal sides, and configured to convey the print fluid into or out of the printhead. The printhead further includes one or more chain manifolds disposed between the I/O ports. 
     In another embodiment, the I/O ports comprise a first I/O port and a second I/O port disposed on a first one of the longitudinal sides. 
     In another embodiment, the printhead further includes one or more supply manifolds disposed longitudinally, and configured to fluidly couple the first I/O port and the second I/O port to the jetting channels. 
     In another embodiment, a first one of the supply manifolds and the chain manifold(s) are defined by a common duct within the printhead. 
     In another embodiment, the I/O ports further comprise a third I/O port and a fourth I/O port disposed on a second one of the longitudinal sides opposite the first one of the longitudinal sides. A first chain manifold of the chain manifold(s) fluidly couples the first I/O port on the first one of the longitudinal sides to the third I/O port on the second one of the longitudinal sides. A second chain manifold of the chain manifold(s) fluidly couples the second I/O port on the first one of the longitudinal sides to the fourth I/O port on the second one of the longitudinal sides. 
     In another embodiment, the first I/O port is staggered in relation to the third I/O port, and the first chain manifold is disposed at an angle across a width of the printhead between the first I/O port and the third I/O port. The second I/O port is staggered in relation to the fourth I/O port, and the second chain manifold is disposed at an angle across the width of the printhead between the second I/O port and the fourth I/O port. 
     In another embodiment, one or more of the I/O ports includes an O-ring. 
     In another embodiment, one or more of the I/O ports includes a hose coupling. 
     Another embodiment comprises a jetting apparatus that includes a mounting bracket configured to mount multiple ones of the printhead in a daisy chain. 
     Another embodiment comprises a jetting apparatus that includes a plurality of printheads installed perpendicular to a direction of relative movement between the printheads and a medium. Each printhead of the plurality comprises a plurality of jetting channels having nozzles configured to jet a print fluid, I/O ports disposed on a longitudinal side of the printhead, and a chain manifold disposed between the I/O ports. The printheads are installed as a daisy-chain via the I/O ports and the chain manifold so that the print fluid flows from one of the printheads to another of the printheads. 
     In another embodiment, the printheads are installed with an outlet I/O port of one of the printheads aligned with an inlet I/O port of another of the printheads. 
     In another embodiment, the jetting apparatus further comprises an O-ring configured to seal a connection between the outlet I/O port and the inlet I/O port. 
     In another embodiment, the printheads at ends of the daisy-chain are connected to a reservoir via a hose. 
     In another embodiment, the printhead further comprises one or more supply manifolds disposed longitudinally, and configured to fluidly couple the I/O ports to the jetting channels. A first one of the supply manifolds and the chain manifold are defined by a common duct. 
     Another embodiment comprises a jetting apparatus that includes a plurality of printheads. Each printhead of the plurality comprises a plurality of jetting channels having nozzles configured to jet a print fluid, I/O ports that comprise a first I/O port and a second I/O port disposed on a first longitudinal side of the printhead, and a third I/O port and a fourth I/O port disposed on a second longitudinal side of the printhead opposite the first longitudinal side, a first chain manifold disposed between the first I/O port on the first longitudinal side and the third I/O port on the second longitudinal side, and a second chain manifold disposed between the second I/O port on the first longitudinal side and the fourth I/O port on the second longitudinal side. The printheads are installed as a daisy-chain via the I/O ports, the first chain manifold, and the second chain manifold so that the print fluid flows from one of the printheads to another of the printheads 
     In another embodiment, the printheads are installed with an outlet I/O port of one of the printheads aligned with an inlet I/O port of another of the printheads. 
     In another embodiment, the jetting apparatus further comprises an O-ring configured to seal a connection between the outlet I/O port and the inlet I/O port. 
     In another embodiment, the printheads at ends of the daisy-chain are connected to a reservoir via a hose. 
     In another embodiment, the printheads are installed at an angle to a direction of relative movement between the printheads and a medium. 
     In another embodiment, the first I/O port is staggered in relation to the third I/O port, and the first chain manifold is disposed at an angle across a width of the printhead between the first I/O port and the third I/O port. The second I/O port is staggered in relation to the fourth I/O port, and the second chain manifold is disposed at an angle across the width of the printhead between the second I/O port and the fourth I/O port. 
     In another embodiment, the printheads are installed parallel to a direction of relative movement between the printheads and a medium. 
     In another embodiment, the first I/O port is transversely aligned with the third I/O port, and the first chain manifold is disposed transversely across a width of the printhead between the first I/O port and the third I/O port. The second I/O port is transversely aligned with the fourth I/O port, and the second chain manifold is disposed transversely across the width of the printhead between the second I/O port and the fourth I/O port. 
     In another embodiment, the printhead further comprises one or more supply manifolds disposed longitudinally, and configured to fluidly couple the I/O ports to the jetting channels. The supply manifolds are fluidly coupled at one end to the first chain manifold, and fluidly coupled at the other end to the second chain manifold. 
     The above summary provides a basic understanding of some aspects of the specification. This summary is not an extensive overview of the specification. It is intended to neither identify key or critical elements of the specification nor delineate any scope particular embodiments of the specification, or any scope of the claims. Its sole purpose is to present some concepts of the specification in a simplified form as a prelude to the more detailed description that is presented later. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Some embodiments of the present disclosure are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings. 
         FIG. 1  is a schematic diagram of a jetting apparatus in an illustrative embodiment. 
         FIG. 2  is a perspective view of a conventional printhead. 
         FIG. 3  is a schematic diagram of a conventional printhead. 
         FIG. 4  is a perspective view of a printhead in an illustrative embodiment. 
         FIG. 5  is a schematic diagram of a printhead in an illustrative embodiment. 
         FIG. 6  illustrates multiple printheads mounted in a jetting apparatus in an illustrative embodiment. 
         FIG. 7  is another perspective view of a printhead in an illustrative embodiment. 
         FIG. 8  is a schematic diagram of a printhead in another illustrative embodiment. 
         FIG. 9  illustrates multiple printheads mounted in a jetting apparatus in an illustrative embodiment. 
         FIG. 10  is a schematic diagram of a printhead in another illustrative embodiment. 
         FIG. 11  illustrates multiple printheads mounted in a jetting apparatus in an illustrative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The figures and the following description illustrate specific exemplary embodiments. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the embodiments and are included within the scope of the embodiments. Furthermore, any examples described herein are intended to aid in understanding the principles of the embodiments, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the inventive concept(s) is not limited to the specific embodiments or examples described below, but by the claims and their equivalents. 
       FIG. 1  is a schematic diagram of a jetting apparatus  100  in an illustrative embodiment. One example of jetting apparatus  100  is an inkjet printer that performs single-pass or multi-pass printing. Jetting apparatus  100  includes a mounting bracket  102  that supports one or more printheads  104  above a medium  112 . Mounting bracket  102  may be disposed on a carriage assembly that reciprocates back and forth along a scan line or scan directions for multi-pass printing. Alternatively, mounting bracket  102  may be fixed within jetting apparatus  100  for single-pass printing. Printheads  104  are a device, apparatus, or component configured to eject droplets  106  of a print fluid, such as ink (e.g., water, solvent, oil, or UV-curable), through a plurality of orifices or nozzles (not visible in  FIG. 1 ). The droplets  106  ejected from the nozzles of printheads  104  are directed toward medium  112 . Medium  112  comprises any type of material upon which ink or another print fluid is applied by a printhead, such as paper, plastic, card stock, transparent sheets, a substrate for 3D printing, cloth, etc. Typically, nozzles of printheads  104  are arranged in one or more rows so that ejection of print fluid from the nozzles causes formation of characters, symbols, images, layers of an object, etc., on medium  112  as printhead  104  and/or medium  112  are moved relative to one another. Media transport mechanism  114  is configured to move medium  112  relative to printheads  104 . Jetting apparatus  100  also includes a jetting apparatus controller  122  that controls the overall operation of jetting apparatus  100 . Jetting apparatus controller  122  may connect to a data source to receive image data, and control each printhead  104  to discharge the print fluid on a desired pixel grid on medium  112 . Jetting apparatus  100  also includes one or more reservoirs  124  for a print fluid. Although not shown in  FIG. 1 , reservoirs  124  may be connected to one or more of printheads  104  via hoses or the like. 
       FIG. 2  is a perspective view of a conventional printhead  200  for a jetting apparatus. Printhead  200  includes a head member  202  and electronics  204 . Head member  202  is an elongated component that forms the jetting channels of printhead  200 . A typical jetting channel includes a nozzle, a pressure chamber, and a diaphragm that is driven by an actuator, such as a piezoelectric actuator. Electronics  204  control how the nozzles of printhead  200  jet droplets in response to control signals. Although not visible in  FIG. 2 , electronics  204  may include a plurality of actuators (e.g., piezoelectric actuators) that contact the diaphragms of the jetting channels. Electronics  204  also include cabling  206 , such as a ribbon cable, that connects to a controller (e.g., jetting apparatus controller  122 ) to receive the control signals. Printhead  200  also includes attachment members  208 , which are configured to secure printhead  200  to a jetting apparatus, such as to mounting bracket  102  as illustrated in  FIG. 1 . Attachment members  208  may include one or more holes  209  so that printhead  200  may be mounted within a jetting apparatus by screws, bolts, pins, etc. 
     The bottom surface  220  of head member  202  includes the nozzles of the jetting channels, and represents the discharge surface of printhead  200 . The top surface  222  of head member  202  represents the I/O portion for receiving print fluids into printhead  200  and/or conveying print fluids (e.g., fluids that are not jetted) out of printhead  200 . Top surface  222 , which is also referred to as the I/O surface, includes a plurality of I/O ports  211 - 212 . Top surface  222  has two ends  226 - 227  that are separated by electronics  204 . I/O port  211  is disposed toward end  226 , and I/O port  212  is disposed toward end  227 . 
     Head member  202  includes a housing  230  and a plate stack  232 . Housing  230  is a rigid member made from stainless steel or another type of material. Housing  230  includes an access hole  234  that provides a passageway for electronics  204  to pass through housing  230  so that actuators may interface with diaphragms of the jetting channels. Plate stack  232  attaches to an interface surface (not visible) of housing  230 . Plate stack  232  (also referred to as a laminate plate stack) is a series of plates that are fixed or bonded to one another to form a laminated stack. Plate stack  232  may include the following plates: one or more nozzle plates, one or more chamber plates, one or more restrictor plates, and a diaphragm plate. A nozzle plate includes a plurality of nozzles that are arranged in one or more rows (e.g., two rows, four rows, etc.). A chamber plate includes a plurality of openings that form the pressure chambers of the jetting channels. A restrictor plate includes a plurality of restrictors that fluidly connect the pressure chambers of the jetting channels with a supply manifold. A diaphragm plate is a sheet of a semi-flexible material that vibrates in response to actuation by an actuator (e.g., piezoelectric actuator). 
       FIG. 3  is a schematic diagram of printhead  200 . The jetting channels  300  of printhead  200  are schematically illustrated in  FIG. 3  as nozzles in two nozzle rows. Printhead  200  includes supply manifolds  311 - 312  that are disposed longitudinally. A supply manifold is a groove, duct, conduit, etc., within head member  202  that is configured to convey or supply a print fluid to jetting channels. Supply manifold  311  is fluidly coupled between I/O ports  211 - 212 , and is also fluidly coupled to a subset of the jetting channels  300  indicated by nozzles  302  via fluid path  304 . Supply manifold  312  is fluidly coupled between I/O ports  211 - 212 , and is also fluidly coupled to a subset of the jetting channels  300  indicated by nozzles  302  via fluid path  304 . Fluid paths  304  are provided in the form of a restrictor, which is a passageway that fluidly couples a supply manifold to a pressure chamber and prevents a backflow of print fluid. 
     Although this design of printhead  200  is effective for its intended purpose, operators may want flexibility in how multiple printheads are connected within a jetting apparatus. In the embodiments described below, the I/O portion is disposed on the side(s) of the printhead, and a manifold(s) (referred to herein as a chain manifold) is disposed through the printhead so that a print fluid may flow through the printhead between I/O ports to act as a supply for another printhead. With this design, multiple printheads may be daisy-chained together within a jetting apparatus. 
       FIG. 4  is a perspective view of a printhead  400  in an illustrative embodiment. Printhead  400  may be an example of a printhead  104  as installed in jetting apparatus  100 . As above for printhead  200 , printhead  400  includes a head member  402  and electronics  404 . Head member  402  is an elongated component that forms the jetting channels of printhead  400 . Printhead  400  includes attachment members  408  that are configured to secure printhead  400  to a jetting apparatus, such as to mounting bracket  102  as illustrated in  FIG. 1 . Attachment members  408  may include one or more holes  409  so that printhead  400  may be mounted within a jetting apparatus by screws, bolts, pins, etc. The bottom surface  420  of head member  402  includes the nozzles of the jetting channels, and represents the discharge surface of printhead  400 . The top surface  422  of head member  402  is opposite the discharge surface. 
     Printhead  400  has longitudinal sides  424 - 425  disposed between bottom surface  420  and top surface  422 . One or both of longitudinal sides  424 - 425  represents the I/O portion for receiving print fluids into printhead  400  and/or conveying print fluids (e.g., fluids that are not jetted) out of printhead  400 . Longitudinal side  424  includes one or more I/O ports  411 - 412 . I/O ports  411 - 412  are spaced by a distance (e.g., a distance more than the length of the jetting channels) so that I/O port  411  is disposed on longitudinal side  424  toward end  426 , while I/O port  412  is disposed on longitudinal side  424  toward end  427 . An I/O port  411 - 412  comprises an opening in head member  402  that acts as an entry point for a print fluid, and/or an exit point for a print fluid. I/O ports  411 - 412  may include a hose coupling, hose barb, etc., for coupling with a supply hose of a reservoir, a cartridge, or the like. I/O ports  411 - 412  may include an O-ring  441 - 442 , a gasket, a seal, or the like, for coupling with another I/O port of another printhead. 
       FIG. 5  is a schematic diagram of printhead  400  in an illustrative embodiment. The jetting channels  500  of printhead  400  are schematically illustrated in  FIG. 5  as nozzles in two nozzle rows, although the nozzles may be arranged in more or less nozzle rows in other embodiments. Printhead  400  includes one or more supply manifolds  511 - 512  that are disposed longitudinally within printhead  400 . As stated above, a supply manifold is a groove, duct, conduit, etc., configured to convey or supply a print fluid to jetting channels. In this embodiment, supply manifold  511  is fluidly coupled to a subset of the jetting channels  500  (or each of the jetting channels  500  in the case of a flow-through printhead) indicated by nozzles  502  via fluid path  504 . Supply manifold  512  is fluidly coupled to a subset of the jetting channels  500  (or each of the jetting channels  500  in the case of a flow-through printhead) indicated by nozzles  502  via fluid path  504 . Fluid paths  504  are provided in the form of restrictors, which are passageways that fluidly couple a supply manifold to a pressure chamber and prevents a backflow of print fluid. Although two supply manifolds are illustrated, there may be a single supply manifold (e.g., such as in the case of a single row of jetting channels), or more than two supply manifolds. 
     In this embodiment, printhead  400  includes a pair of I/O ports  411 - 412  on longitudinal side  424 . Supply manifold  511  fluidly couples I/O ports  411 - 412 , and may further define a chain manifold  513  within printhead  400 . A chain manifold  513  comprises a groove, duct, conduit, etc., configured to convey a print fluid through a printhead for transfer to another printhead. A purpose of a chain manifold is to provide a passageway for a print fluid through a printhead so that multiple printheads may be daisy-chained together. Thus, the size, design, etc., of a chain manifold may be different than a supply manifold, which is used to supply a print fluid to jetting channels. For example, a chain manifold  513  may be larger in size or have a lower flow resistance than a regular supply manifold  512 . Supply manifold  511 /chain manifold  513  may comprise a duct formed within head member  402 , and supply manifold  512  may also comprise a duct formed within head member  402 . In this embodiment, the duct common for supply manifold  511 /chain manifold  513  may be larger than the duct for supply manifold  512  so that the common duct acts as both a supply manifold and a chain manifold. Supply manifold  511 /chain manifold  513  fluidly couples I/O port  411  on longitudinal side  424  with I/O port  412  on the same side. With this configuration, printhead  400  may be installed in a jetting apparatus perpendicular to the direction of relative movement between printhead  400  and the medium. 
       FIG. 6  illustrates multiple printheads  400  mounted in a jetting apparatus  100  in an illustrative embodiment. Printheads  400  are installed perpendicular to the direction of relative movement between printheads  400  and the medium. Printheads  400  are installed as a daisy-chain  600  so that a print fluid flows from one printhead to another. I/O ports  411 - 412  may act as an “inlet” I/O port that receives a flow of print fluid, or an “outlet” I/O port that conveys a flow of print fluid out of a printhead depending on where a printhead  400  is installed in the chain. For example, the “inlet” I/O port  412  on the left-most printhead  400  (i.e., the first printhead) is connected to a supply hose  611 , which is in turn connected to a reservoir or the like. The “outlet” I/O port  411  on the left-most printhead  400  is fluidly coupled to the “inlet” I/O port  411  on the next printhead  400  (i.e., the second printhead) in the chain. I/O port  412  on the second printhead  400  is fluidly coupled to I/O port  412  on the next printhead  400  (i.e., third printhead) in the chain. On the last printhead  400  (i.e., the fifth printhead) in the chain, I/O port  411  is fluidly coupled to a return hose  612  (or another supply hose), which is in turn connected to a reservoir or the like. Printheads  400  may be mounted in jetting apparatus  100  so that the “inlet” I/O port on one printhead  400  is aligned with the “outlet” I/O port on another printhead  400 . An O-ring, gasket, seal, or the like may be used to seal the connection between an “inlet” I/O port and an “outlet” I/O port. 
     As is evident in  FIG. 6 , the ends of daisy-chain  600  (e.g., the leftmost and rightmost printheads  400 ) are connected to one or more reservoirs via hoses  611 - 612 . The printheads  400  are linked together via I/O ports and chain manifold  513  to form an integrated chain manifold  620 . For example, a print fluid may flow from supply hose  611 , into the leftmost printhead  400 , and along integrated chain manifold  620  until exiting the chain at the rightmost printhead  400  through hose  612 . Thus, the interior printheads  400  do not need to be directly connected to a reservoir via a hose, and print fluid may be supplied to these printheads  400  through integrated chain manifold  620 . This makes the printheads  400  easier to install in jetting apparatus  100 , and easier to maintain. 
       FIG. 7  is another perspective view of a printhead  400  in an illustrative embodiment. In this embodiment, longitudinal side  425  of printhead  400  includes one or more I/O ports  713 - 714 . I/O ports  713 - 714  are spaced by a distance (e.g., a distance more than the length of the jetting channels) so that I/O port  713  is disposed on longitudinal side  425  toward end  426 , while I/O port  714  is disposed on longitudinal side  425  toward end  427 . As above, I/O ports  713 - 714  may include a hose coupling  716 , hose barb, etc., for coupling with a supply hose of a reservoir, a cartridge, or the like. I/O ports  713 - 714  may include an O-ring  743 , a gasket, a seal, or the like, for coupling with another I/O port of another printhead. 
       FIG. 8  is a schematic diagram of a printhead  400  in another illustrative embodiment. The jetting channels  500  of printhead  400  are schematically illustrated in  FIG. 8  as nozzles in two nozzle rows, although the nozzles may be arranged in more or less nozzle rows in other embodiments. Printhead  400  includes one or more supply manifolds  511 - 512  that are disposed longitudinally within printhead  400 . As stated above, a supply manifold is a groove, duct, conduit, etc., configured to convey or supply a print fluid to jetting channels. In this embodiment, supply manifold  511  is fluidly coupled to a subset of the jetting channels  500  (or each of the jetting channels  500  in the case of a flow-through printhead) indicated by nozzles  502  via fluid path  504 . Supply manifold  512  is fluidly coupled to a subset of the jetting channels  500  (or each of the jetting channels  500  in the case of a flow-through printhead) indicated by nozzles  502  via fluid path  504 . Fluid paths  504  are provided in the form of restrictors. Although two supply manifolds are illustrated, there may be a single supply manifold (e.g., such as in the case of a single row of jetting channels), or more than two supply manifolds. 
     In this embodiment, printhead  400  includes a pair of I/O ports  411 - 412  on longitudinal side  424 , and a pair of I/O ports  713 - 714  on longitudinal side  425 . Printhead  400  also includes chain manifolds  813 - 814 . Chain manifold  813  fluidly couples I/O port  713  on longitudinal side  425  with I/O port  411  on longitudinal side  424 . I/O port  713  is staggered in relation to I/O port  411 , meaning that they are not transversely aligned across the width of printhead  400 . Thus, chain manifold  813  is disposed at an angle across the width of printhead  400  between I/O port  713  and I/O port  411 . Chain manifold  814  fluidly couples I/O port  714  on longitudinal side  425  with I/O port  412  on longitudinal side  424 . I/O port  714  is staggered in relation to I/O port  412 , meaning that they are not transversely aligned across the width of printhead  400 . Thus, chain manifold  814  is disposed at an angle across the width of printhead  400  between I/O port  714  and I/O port  412 . With this configuration, printhead  400  may be installed in a jetting apparatus at an angle in relation to the direction of relative movement between printhead  400  and the medium. Supply manifolds  511 - 512  are fluidly coupled at one end to chain manifold  813 , and fluidly coupled at the other end to chain manifold  814 . 
       FIG. 9  illustrates multiple printheads  400  mounted in a jetting apparatus  100  in an illustrative embodiment. In this embodiment, printheads  400  are installed at an angle in relation to the direction of relative movement between printheads  400  and the medium, such as at an angle in the range of 52 and 54 degrees, in the range of 36 and 38 degrees, or at another angle. Printheads  400  are installed as a daisy-chain  900  so that a print fluid flows from one printhead to another. I/O ports  411 - 412  and  713 - 714  may act as an “inlet” I/O port that receives a flow of print fluid, or an “outlet” I/O port that conveys a flow of print fluid out of a printhead depending on where a printhead  400  is installed in the chain. For example, the “inlet” I/O ports  713 - 714  on the left-most printhead  400  (i.e., the first printhead) are connected to supply hoses  910 - 911 , respectively, which are in turn are connected to a reservoir or the like. The “outlet” I/O ports  411 - 412  on the left-most printhead  400  are fluidly coupled to the “inlet” I/O ports  713 - 714  on the next printhead  400  (i.e., the second printhead) in the chain. The “outlet” I/O ports  411 - 412  on the second printhead  400  are connected to the “inlet” I/O ports  713 - 714  on the next printhead  400  (i.e., the third printhead) in the chain. Other printheads  400  are fluidly coupled in a similar manner. On the right-most printhead  400  (i.e., the sixth printhead) in the chain, the “outlet” I/O ports  411 - 412  are fluidly coupled to return hoses  912 - 913  (or another supply hose), respectively, which in turn are connected to a reservoir or the like. Printheads  400  may be mounted in jetting apparatus  100  so that the “inlet” I/O ports on one printhead  400  are aligned with the “outlet” I/O ports on another printhead  400 . An O-ring, gasket, seal, or the like may be used to seal the connection between an “inlet” I/O port and an “outlet” I/O port. 
     As is evident in  FIG. 9 , the ends of daisy-chain  900  (e.g., the leftmost and rightmost printheads  400 ) are connected to one or more reservoirs via hoses  910 - 913 . The printheads  400  are linked together via I/O ports and chain manifolds  813 - 814  to form integrated chain manifolds  920 . For example, a print fluid may flow from supply hose  910 , into the leftmost printhead  400 , and along one of the integrated chain manifolds  920  until exiting the chain at the rightmost printhead  400  through hose  912 . The print fluid may flow from supply hose  911 , into the leftmost printhead  400 , and along the other integrated chain manifold  920  until exiting the chain at the rightmost printhead  400  through hose  913 . Thus, the interior printheads  400  do not need to be directly connected to a reservoir via a hose, and print fluid may be supplied to these printheads  400  through integrated chain manifolds  920 . This makes the printheads  400  easier to install in jetting apparatus  100 , and easier to maintain. 
       FIG. 10  is a schematic diagram of a printhead  400  in another illustrative embodiment. The jetting channels  500  of printhead  400  are schematically illustrated in  FIG. 10  as nozzles in two nozzle rows, although the nozzles may be arranged in more or less nozzle rows in other embodiments. Printhead  400  includes one or more supply manifolds  511 - 512  that are disposed longitudinally within printhead  400 . As stated above, a supply manifold is a groove, duct, conduit, etc., configured to convey or supply a print fluid to jetting channels. In this embodiment, supply manifold  511  is fluidly coupled to a subset of the jetting channels  500  (or each of the jetting channels  500  in the case of a flow-through printhead) indicated by nozzles  502  via fluid path  504 . Supply manifold  512  is fluidly coupled to a subset of the jetting channels  500  (or each of the jetting channels  500  in the case of a flow-through printhead) indicated by nozzles  502  via fluid path  504 . Fluid paths  504  are provided in the form of restrictors. Although two supply manifolds are illustrated, there may be a single supply manifold (e.g., such as in the case of a single row of jetting channels), or more than two supply manifolds. 
     In this embodiment, printhead  400  includes a pair of I/O ports  411 - 412  on longitudinal side  424 , and a pair of I/O ports  713 - 714  on longitudinal side  425 . Printhead  400  also includes chain manifolds  1013 - 1014 . Chain manifold  1013  fluidly couples I/O port  713  on longitudinal side  425  with I/O port  411  on longitudinal side  424 . I/O port  713  is transversely aligned with I/O port  411  across the width of printhead  400 . Thus, chain manifold  1013  is disposed transversely across the width of printhead  400  between I/O port  713  and I/O port  411 . Chain manifold  1014  fluidly couples I/O port  714  on longitudinal side  425  with I/O port  412  on longitudinal side  424 . I/O port  714  is transversely aligned with I/O port  412  across the width of printhead  400 . Thus, chain manifold  1014  is disposed transversely across the width of printhead  400  between I/O port  714  and I/O port  412 . With this configuration, printhead  400  may be installed in a jetting apparatus parallel to the direction of relative movement between printhead  400  and the medium. Supply manifolds  511 - 512  are fluidly coupled at one end to chain manifold  1013 , and fluidly coupled at the other end to chain manifold  1014 . 
       FIG. 11  illustrates multiple printheads  400  mounted in a jetting apparatus  100  in an illustrative embodiment. In this embodiment, printheads  400  are installed parallel to the direction of relative movement between printheads  400  and the medium. Printheads  400  are installed as a daisy-chain  1100  so that a print fluid flows from one printhead to another. I/O ports  411 - 412  and  713 - 714  may act as an “inlet” I/O port that receives a flow of print fluid, or an “outlet” I/O port that conveys a flow of print fluid out of a printhead depending on where a printhead  400  is installed in the chain. For example, the “inlet” I/O ports  713 - 714  on the left-most printhead  400  (i.e., the first printhead) are connected to supply hoses  1110 - 1111 , respectively, which are in turn are connected to a reservoir or the like. The “outlet” I/O ports  411 - 412  on the left-most printhead  400  are fluidly coupled to the “inlet” I/O ports  713 - 714  on the next printhead  400  (i.e., the second printhead) in the chain. The “outlet” I/O ports  411 - 412  on the second printhead  400  are connected to the “inlet” I/O ports  713 - 714  on the next printhead  400  (i.e., the third printhead) in the chain. Other printheads  400  are fluidly coupled in a similar manner. On the right-most printhead  400  (i.e., the fourth printhead) in the chain, the “outlet” I/O ports  411 - 412  are fluidly coupled to return hoses  1112 - 1113  (or another supply hose), respectively, which in turn are connected to a reservoir or the like. Printheads  400  may be mounted in jetting apparatus  100  so that the “inlet” I/O ports on one printhead  400  are aligned with the “outlet” I/O ports on another printhead  400 . An O-ring, gasket, seal, or the like may be used to seal the connection between an “inlet” I/O port and an “outlet” I/O port. 
     As is evident in  FIG. 11 , the ends of daisy-chain  1100  (e.g., the leftmost and rightmost printheads  400 ) are connected to one or more reservoirs via hoses  1110 - 1113 . The printheads  400  are linked together via I/O ports and chain manifolds  1013 - 1014  to form integrated chain manifolds  1120 . For example, a print fluid may flow from supply hose  1110 , into the leftmost printhead  400 , and along one of the integrated chain manifolds  1120  until exiting the chain at the rightmost printhead  400  through hose  1112 . The print fluid may flow from supply hose  1111 , into the leftmost printhead  400 , and along the other integrated chain manifold  1120  until exiting the chain at the rightmost printhead  400  through hose  1113 . Thus, the interior printheads  400  do not need to be directly connected to a reservoir via a hose, and print fluid may be supplied to these printheads  400  through integrated chain manifolds  1120 . This makes the printheads  400  easier to install in jetting apparatus  100 , and easier to maintain. 
     Although specific embodiments were described herein, the scope of the invention is not limited to those specific embodiments. The scope of the invention is defined by the following claims and any equivalents thereof.