Abstract:
A maintenance cart is configured so the maintenance units within the cart can be selectively moved to correspond to a scalable printhead array. The maintenance cart includes a body configured to selectively move along a path to the printhead array, the body having a recess; and a plurality of cleaning modules mounted within the recess, the plurality of cleaning modules being adjustably arranged within the recess to correspond to a plurality of printheads of the printhead array to enable each cleaning module in the plurality of cleaning modules to align with a corresponding printhead of the printhead array in response to the body being moved to the printhead array.

Description:
TECHNICAL FIELD 
     The apparatus disclosed in this document relates to inkjet printers and, more particularly, to maintenance of scalable inkjet printhead arrays. 
     BACKGROUND 
     Inkjet printing is a process of producing an image on a substrate, such as a sheet of paper. Inkjet printing is an additive process in which one or more printheads eject drops of ink onto the substrate to form the image on the substrate. The printheads are operated with reference to digital image data that represents the image to be printed. Printing a multicolored image generally requires at least one printhead for each color. Additionally, printing high resolution images often requires multiple printheads of the same color that are interlaced to provide the increased resolution. Accordingly, many inkjet printing systems comprise arrays of several printheads arranged in rows and columns. 
       FIG. 9  shows a prior art architecture for a scalable printhead array  900 . The printhead array  900  includes a plurality of printhead assemblies  904 . The printhead array  900  is configured to include a variable number of printhead assemblies  904  arranged into rows and columns in a variety of possible arrangements. As shown, the printhead array  900  is scalable up to 50″ in width and includes up to fourteen printhead assemblies  904 . Each printhead assembly  904  is configured to receive a printhead module  908  and to mount to frame  912  of the printhead array  900 .  FIG. 10  shows a more detailed view of one of the printhead assemblies  904  with a printhead module  908 . 
     To ensure optimal performance of an inkjet printhead, the printheads must be well-maintained. Typically maintenance operations include purging, capping, and wiping. Prior art mechanisms for printhead maintenance are not easily adapted for scalable printhead arrays. Being able to configure a printhead maintenance system so it is easily scalable for use with a scalable printhead array would be beneficial. 
     SUMMARY 
     A maintenance cart for maintaining a scalable printhead array has been developed. The maintenance cart includes a body configured to selectively move along a path to the printhead array, the body having a recess; and a plurality of cleaning modules mounted within the recess, the plurality of cleaning modules being adjustably arranged within the recess to correspond to a plurality of printheads of the printhead array to enable each cleaning module in the plurality of cleaning modules to align with a corresponding printhead of the printhead array in response to the body being moved to the printhead array. 
     A printer includes a printhead array have a plurality of printheads; a track defining a path leading to and from the printhead array; and a maintenance cart configured to selectively move along the track to and from the printhead array to perform maintenance operations on the printhead array, the maintenance cart comprising: a body having a recess; and a plurality of cleaning modules mounted within the recess, the plurality of cleaning modules being adjustably arranged within the recess to correspond to the plurality of printheads of the printhead array to enable each cleaning module in the plurality of cleaning modules to align with a corresponding printhead of the printhead array in response to the body being moved to the printhead array. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and other features of printhead maintenance systems are explained in the following description, taken in connection with the accompanying drawings. 
         FIG. 1  shows a perspective view maintenance cart for maintaining a scalable printhead array and a scalable printhead array. 
         FIG. 2  shows a perspective view of the maintenance cart at an operating position beneath the scalable printhead array. 
         FIG. 3  shows a side view of the maintenance cart at an operating position beneath the scalable printhead array. 
         FIG. 4  shows a perspective view of a maintenance module. 
         FIG. 5  shows a side view of a maintenance module without an enclosure aligned with a corresponding printhead assembly of the scalable printhead array. 
         FIG. 6  shows a side view of a maintenance module without an enclosure and body aligned with a corresponding printhead assembly of the scalable printhead array. 
         FIG. 7  shows a side view of a maintenance module without an enclosure with a seal pressed against a surface of the printhead of the printhead assembly. 
         FIG. 8  shows a perspective view of a maintenance module without an enclosure with a seal pressed against a surface of the printhead of the printhead assembly. 
         FIG. 9  shows a prior art scalable printhead array. 
         FIG. 10  shows a prior art printhead assembly and printhead. 
     
    
    
     DETAILED DESCRIPTION 
     For a general understanding of the environment for the maintenance cart disclosed herein as well as the details for the maintenance cart, reference is made to the drawings. In the drawings, like reference numerals designate like elements. 
       FIG. 1  shows a printer having maintenance cart  100  for maintaining a scalable printhead array  104 , which is similar to the printhead array  900 . The maintenance cart  100  has a cart body  108 . The cart body  108  has a wall that forms a continuous perimeter having a recess  112  within the perimeter. A plurality of maintenance modules  116  is disposed within the recess  112 . A set of wheels  120  are mounted to the cart body  108  and configured to engage with a track, such as a pair of rails  124 , to enable the maintenance cart  100  to move along the rails  124  to and from the printhead array  104 . In one embodiment, the rails  124  are also used by a media cart configured to convey a substrate to and from the printhead array  104  for printing operations. 
     The printhead array  104  has a configuration of printhead assemblies  128 , similar to the printhead assemblies  904 . In the embodiment of  FIG. 1 , the printhead assemblies  128  are arranged in two rows. The printhead array  104  has a variable number of printhead assemblies  128  arranged in each of the two rows. The maintenance modules  116  of the maintenance cart  100  are arranged within the recess  112  in a configuration that corresponds to the configuration of printhead assemblies  128  in the printhead array  104  such that when the maintenance cart  100  moves beneath the printhead array the maintenance modules  116  align with printhead assemblies  128  in a one-to-one correspondence. In the embodiment shown in  FIG. 1 , the maintenance cart  100  has variable number of maintenance modules  116  arranged in two rows to match the two rows of printhead assemblies  128  in the printhead array  104 . 
     In one embodiment, the maintenance cart  100  includes shafts  134  that extend across the recess  112 . The maintenance modules  116  are adjustably arranged along the shafts  134  in a configuration that matches the configuration of the printhead assemblies  128  in the printhead array  104 . The maintenance modules  116  are configured to slide along the shafts  134  and selectively fixed to the shafts to enable their configuration to be easily adjusted to match the configuration of the printhead assemblies  128  in the printhead array  104 . Accordingly, if the configuration of the printhead assemblies  128  is modified, the maintenance modules in the current configuration are released from the shafts, moved to a location that corresponds to one of the printheads the printhead assemblies, and fixed at those locations to match the new configuration of printhead assemblies  128 . In this way, the maintenance cart  100  has the same scalability and customizability as the printhead array  104 . As used in this document, the term “adjustably arranged” refers to the maintenance modules being configured for selective movement to correspond to different configurations of printheads in printhead assemblies. 
     To perform maintenance operations on the printhead array  104 , the maintenance cart  100  moves along the rails  124  to an operating position  132  located beneath the printhead array  104  and between the printhead array  104  and the rails  124 .  FIG. 2  and  FIG. 3  show the maintenance cart  100  positioned at the operating position  132  beneath the printhead array  104 . Once positioned at the operating position  132 , the maintenance modules  116  of the maintenance cart  100  perform maintenance operations on the printheads of the printhead assemblies  128  of the printhead array  104 . In some embodiments, the maintenance operations include one or more of: purging ink from the printheads, wiping debris from a surface of the printheads, and capping the printheads with a seal. After the maintenance modules  116  perform the maintenance operations, the maintenance cart  100  moves along the rails  124  away from the printhead array  104 . 
       FIG. 4  shows a maintenance module  400 . The maintenance module  400  comprises a body  404 . In one embodiment, the body  404  has an upper portion  408  and a lower portion  412  (shown in  FIG. 5 ). The upper portion  408  has a continuous perimeter that defines a recess  416 . A wiper blade  420  is mounted within the recess  416  and configured to extend from the recess  416  in a direction pointing away from the lower portion  412  of the body  404 . In one embodiment, the wiper blade  420  is mounted with a mount  424 . The wiper blade  420  is configured to be detachably connected to mount  424  to enable easy replacement of the wiper blade  420 . A wiping cloth  428  is similarly mounted within the recess  416 . In one embodiment, the wiping cloth  428  is a flexible material entrained in a closed loop around rollers  432  (shown in  FIG. 6 ). The flexible material in some embodiments is porous to facilitate the absorption of material on the face of a printhead by the flexible material. The rollers  432  are configured to rotate the wiping cloth  428  about the closed loop. A tray  436  is mounted within the recess  416  to receive debris dislodged by the wiper blade  420  and the wiping cloth  428 . In some embodiments, the maintenance module  400  includes an enclosure  440 . The body  404  is disposed within the enclosure  440 . In one embodiment, the enclosure  440  is configured to mount onto the shafts  134  via holes  444 . 
       FIG. 5  shows the maintenance module  400  aligned with a printhead assembly  500  of printhead array  104 . In  FIG. 5 , the maintenance module  400  is shown without the enclosure  440 . In one embodiment, the maintenance module  400  includes a base  504 . An actuator, such as the cam  508 , is mounted to the base  504 . The cam  508  is configured to interface with the body  404 . Particularly, the cam  508  is configured to rotate and move the body  404  towards the printhead assembly  500 . In one embodiment, base  504  is mounted within the enclosure  440  and is fixed in place with respect to the enclosure  440 , while the body  404  is configured to move freely with respect to the enclosure  440 . 
     When maintenance operations are performed, the maintenance module  400  is aligned with a printhead  512  of the printhead assembly  500 . Once the maintenance module  400  is aligned with the printhead  512 , a controller commands the cam  508  to rotate and move the body  404  toward the printhead  512  to bring the wiper blade  420  and the wiping cloth  428  into contact with a surface  516  of the printhead  512 . In one embodiment, the maintenance cart  100  moves along the rails  124  relative to the printhead  512  so that the wiper blade  420  and then the wiping cloth  428  wipe against the surface  516  to remove debris. As shown in  FIG. 6 , the tray  436  is positioned beneath the wiper blade  420  and the wiping cloth  428  to catch any debris that falls from the surface  512 . In one embodiment, maintenance operations are only performed on printheads that were used since a prior maintenance operation. 
     The maintenance module  400  further includes a seal  448  mounted to the body  404 . An actuator is configured to move the seal  684  outward from the body  404  toward the surface  516  of the printhead  512  to press against the surface  516 . As shown in  FIG. 7 , after the surface  516  has been wiped clean, the seal  448  presses the surface  516  to establish an air-tight seal around at least part of the surface  516 . The seal established by the seal  448  prevents inkjets of the printhead  512  from drying out.  FIG. 8  shows a perspective view of the maintenance module  400  with the seal  448  pressed against the printhead  512  to establish a seal around at least part of the surface  516  of the printhead  512 . 
     It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems, applications or methods. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art, which are also intended to be encompassed by the following claims.