Patent Publication Number: US-9895889-B2

Title: Printhead assembly

Description:
BACKGROUND 
     End users appreciate reliability and speed in their printing devices. They also appreciate quality output from printing devices, as well as cost-effective solutions for their printing needs. Designers and manufacturers may, therefore, endeavor to create and provide printing device components directed toward at least some of these objectives. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description references the drawings, wherein: 
         FIG. 1  is an example of a printhead assembly. 
         FIG. 2  is an example of a cross-sectional view of the printhead assembly of  FIG. 1  taken along line  2 - 2  of  FIG. 1 . 
         FIG. 3  is an example of the printhead assembly of  FIG. 2  illustrating the attraction and collection of particles. 
         FIG. 4  is an example of an enlarged view of the attraction and collection of particles of a negative polarity and attract on and collection of particles of a positive polarity. 
         FIG. 5  is an example of the printhead assembly of  FIG. 3  illustrating servicing thereof. 
         FIG. 6  is another example of a printhead assembly. 
         FIG. 7  is an additional example of a portion of a printhead assembly. 
         FIG. 8  is a further example of a portion of a printhead assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Printing devices deposit priming composition onto media. Printing devices may utilize at least one or more printheads to deposit the printing composition onto the media. Particles may collect on and/or be attracted to these one or more printheads. They also may be present in the printzone of a printing device. These particles can come from a variety of sources and places such as, for example, media fibers, dust, printing composition aerosol, hair, skin, fur and/or other debris. 
     Output print quality of a printing device degrades if these particles are allowed to collect on printheads. Such particles can be difficult to remove from these one or more printheads during servicing or maintenance thereof. This difficulty may arise, for example, due to electrostatic charge differences between the one or more printheads and these particles. Such ineffective servicing or maintenance of these one more printheads will result in a continuance of the degradation of the output print quality of a printing device causing end user dissatisfaction. 
     Output print quality degradation also results in wasted printing composition and media because print jobs need to be rerun which adds cost to the operation of printing devices. It also degrades printing device reliability and wastes end user time. Particle collection on the one or more printheads additionally increases the frequency of printhead servicing or maintenance which decreases print job speed of printing devices, resulting in additional end user dissatisfaction. 
     Examples directed to mitigating these challenges associated with particle collection on the one or more printheads of a printing device, as well as particles in the printzone of a printing device, are shown in  FIGS. 1-8 . These examples help to address the above-described issues caused by such particles, thereby helping to improve output print quality, lower the cost of use, increase print job speed, and maintain reliability of printing devices. 
     As used herein the term “printing device” represents a printer, plotter, press and/or device that uses any of the following Marking technologies or ft combination thereof: ink jet, dye sublimation, thermal transfer, 3D, laser, extrusion, off-set printing, or dot matrix. As used herein the terms “media” and “medium” are interchangeable and represent any type of paper or other printing medium (e.g., cloth, cardboard, canvas, transparency, substrate, etc.), having any type of finish on either or both sides (e.g., glossy, matte, plain, textured, etc.), in any size, shape, color, or form (e.g., sheet, roll (cut or uncut), folded, etc.) on which printing composition (e.g., ink, toner, colorant, wax, dye, powder, latex, printing fluid or solid, etc.) is placed, jetted, deposited, dropped, ejected, formed, or laid to create text or items (e.g., text, images, graphics, pictures, formulas, charts, two-dimensional objects, three-dimensional objects, etc.). 
     As used herein, the terms “head” and “printheads” represent a mechanism or device that implements any of the above-described marking technologies. A print head or print heads can be a single device or mechanism, or arranged in a module or array such as, for example, a print bar or page-wide array. As used herein, the term “printzone” represents the area, location or portion of a printing device where a printhead or printheads utilize printing composition to create images and/or items on a medium. 
     An example of a printhead assembly  10  is shown in  FIG. 1 . As can be seen in  FIG. 1 , printhead assembly  10  includes a base member  12  and a plurality of dies  14 ,  16 ,  18 ,  20 , and  22  to print. As can also be seen in  FIG. 1 , printhead assembly  10  additionally includes an electrode  24  to provide a charge (e.g., positive) to attract and collect particles of a polarity (e.g., negative). As can also be seen in  FIG. 1 , printhead assembly  10  may also include an additional electrode  26  to provide a charge (e.g., negative) attract and collect particles of a polarity (e.g., positive). Base member  12  is coupled to dies  14 ,  16 ,  18 ,  20 , and  22  and electrodes  24  and  26  to provide support to them. Base member  12  is also electrically connected to each of dies  14 ,  16 ,  18 ,  20 , and  22  and electrodes  24  and  26 , as discussed more fully below. 
     As can additionally be seen in  FIG. 1 , electrodes  24  and  26  of printhead assembly  10  are continuous structures extending along a length  25  of base  12 . As can further be seen in  FIG. 1 , each of dies  14 ,  16 ,  18 ,  20 , and  22  includes a respective longitudinal axis  15 ,  17 ,  19 ,  21 , and  23  and both electrodes  24  and  26  are substantially parallel to longitudinal axes  15 ,  17 ,  19 ,  21 , and  23 . In other examples of printhead assembly  10 , electrode  24  and/or electrode  26  may be discontinuous structures. Additionally or alternatively, in other examples of printhead assembly  10 , electrode  24  and/or electrode  26  may be other than substantially parallel to longitudinal axes  15 ,  17 ,  19 ,  21 , and  23  of respective dies  14 ,  16 ,  18 ,  20 , and  22 . For example, electrode  24  and/or electrode  26  may be substantially perpendicular to one or more of longitudinal axes  15 ,  17 ,  19 ,  21 , and  23  of respective dies  14 ,  16 ,  18 ,  20 , and  22 . As another example, electrode  24  and/or electrode  26  may encircle at least a portion of one or more of dies  14 ,  16 ,  18 ,  70 , and  22 . 
     An example of a cross-sectional view of printhead assembly  10  taken along line  2 - 2  of  FIG. 1  is shown in  FIG. 2 . As can be seen in  FIG. 2 , in this example, die  16  of print head assembly  10  includes slivers  28 ,  30 ,  32 , and  34  coupled to base  12 . Each of slivers  28 ,  30 ,  32  and  34  typically includes an integrated circuit formed on respective substrates  36 ,  38 ,  40 , and  42 . Each of slivers  28 ,  30 ,  32 , and  34  also include a respective chamber layer and a nozzle plate  44 ,  46 ,  48 , and  50  which are shown as single structures, for purposes of illustration, and may actually each include multilayer structures. 
     As can also be seen in  FIG. 2 , each of slivers  28 ,  30 ,  32 , and  34  additionally include respective nozzles  52 ,  54 ,  56 , and  58 , coupled to respective flow passages  60 ,  62 ,  64 , and  66 , through which printing composition is ejected, as discussed more fully below. Although a single nozzle  52 ,  54 ,  56 , and  58  is illustrated for each of slivers  28 ,  30 ,  32 , and  34 , it is to be understood that in other examples of printhead assembly  10 , slivers  28 ,  30 ,  32  and/or  34  may include additional nozzles and/or flow passages  60 ,  62 ,  64 , and  66  through which the same color or different colors of printing composition are ejected. Additionally, although not shown, it is to be understood that in other examples of printhead assembly  10 , die  16  may include fewer (e.g., one) or more slivers with one or plurality of nozzles and/or flow passages. 
     As can additionally be seen in  FIG. 2 , base member  12  includes a printed circuit board  68  coupled and electrically connected to die  16  and electrodes  24  and  26 . In this example of printhead assembly  10 , electrodes  24  and  26  are connected to printed circuit board  68  by respective conductors  70  and  72 , and each of slivers  28 ,  30 ,  32 , and  34  of die  16  are connected to printed circuit board  68  by respective pairs of conductors  74  and  76 ,  78  and  80 ,  82  and  84 , and  86  and  88 . Although not shown, it is to be understood that in other examples of printhead assembly  10 , more than one conductor may be used to connect printed circuit board  68  to electrodes  24  and  26  and fewer or more conductors may be used to connect printed circuit board  68  to each of slivers  28 ,  30 ,  32 , and  34 . 
     As can thither be seen in  FIG. 2 , printhead assembly  10  also includes a printing composition channel  92 ,  94 ,  96 , and  98  in printed circuit board  68  of base member  12  adjacent respective slivers  28 ,  30 ,  32 , and  34  of die  16 . In this example, printing composition channels  92 ,  94 ,  96 , and  98  extend to a portion of each of respective substrates  36 ,  38 ,  40 , and  42 . Printing composition channels  92 ,  94 ,  96 , and  98  are coupled to respective flow passages  60 ,  62 ,  64 , and  66  of slivers  28 ,  30 ,  32 , and  34  to supply printing composition thereto. Although not shown, it is to be understood that in other examples of printhead assembly  10 , fewer (e.g. one) or more printing composition channels may be utilized. 
     As can still further be seen in  FIG. 2 , base member  12  also includes a molding  90  over at least a portion of electrodes  24  and  26 , slivers  28 ,  30 ,  32 , and  34  of die  16 , and printed circuit board  68 . Molding  90  helps to protect electrodes  24  and  26 , slivers  28 ,  30 ,  32 , and  34  of die  16 , and printed circuit board  68 , as well as to support and couple them together. Although not shown, it is to be understood that in other examples of printhead assembly  10 , molding  90  may not be over at least a portion of electrodes  24  and  26 , slivers  28 ,  30 ,  32  and  34  of die  16  and/or printed circuit board  68 . 
     As can yet further be seen in  FIG. 2 , a medium  100  is traveling under and toward printhead assembly  10 , as generally indicated by arrow  102 . Medium  100  includes particles  104  on medium  100  which are undesirable for at least the reasons discussed above. Although not shown, particles  104  may also be present around printhead assembly  10  in printzone  106 . Additionally, although not shown, it is to be understood that the above-described and following description and illustration of die  16  applies as well to dies  14 ,  18 ,  20  and  22 . 
     An example of printhead assembly  10  illustrating the attraction and collection of particles  104  on medium  100  is shown in  FIG. 3 . As can be seen in  FIG. 3 , in this example, particles  104  include both particles of a negative polarity  108  that are attracted and collected by electrode  24  and particles of a positive polarity  110  that are attracted and collected by electrode  26 .  FIG. 4  is an example of an enlarged view of this attraction and collection of particles of a negative polarity  108  by electrode  24  and this attraction and collection of particles of a positive polarity  110  by electrode  26 . 
     Referring again to  FIG. 3 , particles  104  on medium  100 , as well as those in and adjacent to printzone  106 , are attracted and collected by electrodes  24  and  26  prior to the ejection of printing composition  112 ,  114 ,  116 , and  118  onto medium  100  by respective nozzles  52 ,  54 ,  56 , and  58 . This helps to maintain print quality of printhead assembly  10  which could be otherwise be degraded by particles  104 . As can also be seen in  FIG. 3 , in this example, printing composition  112  is cyan, printing composition  114  is magenta, printing composition  116  is yellow, and printing composition  118  is black. Although not shown, it is to be understood, however, that other examples of printhead assembly  10  may utilize one or more different colors of printing composition. Alternatively, printing composition  112 ,  114 ,  116 , and  118  may all be of the same color. 
     An example of printhead assembly  10  illustrating servicing thereof is shown in  FIG. 5 . As can be seen in  FIG. 5 , electrode  24  may be connected to base member  12  to provide a negative charge to repel previously collected particles  108  of a negative polarity during servicing of die  16  by wiper  120 , as generally indicated by arrow  122 , which removes particles  108  from electrode  24 . As can also be seen in  FIG. 5 , electrode  26  may be connected to base member  12  to provide a positive charge to repel previously collected particles  110  of a positive polarity during servicing of die  16  by wiper  120  which removes particles  110  from electrode  26 . Although a wiper  120  is shown servicing die  16  and removing particles  105  and  110  from respective electrodes  24  and  26  in  FIG. 5 , it is to be understood that in other examples of printhead assembly  10 , different structures or techniques may be utilized to service die  16  and/or remove particles  108  and  110  from respective electrodes  24  and  26 . 
     An example of another printhead assembly  124  is shown in  FIG. 6 . Where possible, the same reference numerals have been used for the elements of printhead assembly  124  that are the same as the elements of printhead assembly  10 . As can be seen in  FIG. 6 , base member  126  of printhead assembly  124  includes an electrical redistribution layer  128  connected to electrodes  24  and  26 , as well as each of slivers  28 ,  30 ,  32 , and  34  of die  16 . Base member  126  also includes a molding  130  over at least a portion of slivers  28 ,  30 ,  32 , and  34  of die  16  to help protect slivers  28 ,  30 ,  32 , and  34  of die  16 , as well as to support and couple them together. 
     As can also be seen in  FIG. 6 , printhead assembly  10  additionally includes a printing composition channel  92 ,  944 ,  96 , and  988  in molding  130  of base member  126  adjacent respective slivers  28 ,  30 ,  32 , and  34  of die  16 . In this example, printing composition channels  92 ,  94 ,  96 , and  98  extend to a portion of each of respective substrates  36 ,  38 ,  40 , and  42 . Printing composition channels  92 ,  94 ,  96 , and  98  are coupled to respective flow passages  60 ,  62 ,  64 , and  66  of slivers  28 ,  30 ,  32 , and  34  to supply printing composition thereto. Although not shown, it is to be understood that in other examples of printhead assembly  124 , fewer (e.g. one) or more printing composition channels may be utilized. 
     As can additionally be seen in  FIG. 6 , redistribution layer  128  also includes metal traces  132  and a dielectric layer  134  over at least a portion of slivers  28 ,  30 ,  32 , and  34  of die  16  and molding  130  to help protect slivers  28 ,  30 ,  32 , and  34  of die  16  and molding  130 . Although not shown, it is to be understood that in other examples of printhead assembly  124 , dielectric layer  134  may not be over at least a portion of slivers  28 ,  30 ,  32 , and  34  of die  16  and/or molding  130 . Additionally, it is to be understood that the above-described example of servicing of printhead assembly  10  shown in  FIG. 5  is also applicable to servicing of printhead assembly  124 . 
     An additional example of a portion of a printhead assembly  134  is shown in  FIG. 7 . Where possible, the same reference numerals have been used for the elements of printhead assembly  134  that are the same as the elements of printhead assembly  10 . As can be seen in  FIG. 7 , electrodes  24  and  26  of printhead assembly  134  are discontinuous structures extending along lengths  136  and  138  of respective dies  14  and  16 . As can also be seen in  FIG. 7 , each of dies  14  and  16  includes a respective longitudinal axis  140  and  142  and both electrodes  24  and  26  are substantially parallel to longitudinal axes  140  and  142 . As can additionally be seen in  FIG. 7 , each of dies  14  and  16  includes a respective side  144  and  146  and both electrodes  24  and  26  are located adjacent sides  144  and  146 . 
     It is to be understood that the above-described example of servicing of printhead assembly  10  shown in  FIG. 5  is also applicable to servicing of printhead assembly  134 . In other examples of printhead assembly  134 , electrode  24  and/or electrode  26  may be continuous structures. Additionally or alternatively, in other examples of printhead assembly  134 , electrode  24  and/or electrode  26  may be other than substantially parallel to longitudinal axes  140  and  142  of respective dies  14  and  16 . For example, electrode  24  and/or electrode  26  may be substantially perpendicular to one or more of longitudinal axes  140  and  142  of respective dies  14  and  16 . As another example, electrode  24  and/or electrode  26  may encircle at least a portion of one or more of dies  14  and  16 . 
     A further example of a portion of a printhead assembly  148  is shown in  FIG. 8 . Where possible, the same reference numerals have been used for the elements of printhead assembly  148  that are the same as the elements of printhead assembly  10 . As can be seen in  FIG. 8 , electrodes  24  and  26  of printhead assembly  148  are discontinuous structures extending along lengths  150  and  152  of respective dies  14  and  16 . As can also be seen in  FIG. 8 , each of dies  14  and  16  includes a respective longitudinal axis  154  and  156  and both electrodes  24  and  26  are substantially parallel to longitudinal axes  154  and  156 . As can additionally be seen in  FIG. 8 , each of dies  14  and  16  includes a respective side  158  and  160  and electrodes  24  are located adjacent sides  158  and  160 . As can further be seen in  FIG. 8 , each of dies  14  and  16  includes a respective side  162  and  164  and electrodes  26  are located adjacent sides  162  and  164 . 
     It is to be understood that the above-described example of servicing of printhead assembly  10  shown in  FIG. 5  is also applicable to servicing of printhead assembly  148 . In other examples of printhead assembly  148 , electrode  24  and/or electrode  26  may be continuous structures. Additionally or alternatively, in other examples of printhead assembly  148 , electrode  24  and/or electrode  26  may be other than substantially parallel to longitudinal axes  154  and  156  of respective dies  14  and  16 . For example, electrode  24  and/or electrode  26  may be substantially perpendicular to one or more of longitudinal axes  154  and  156  of respective dies  14  and  16 . As another example, electrode  24  and/or electrode  26  may encircle at least a portion of one or more of dies  14  and  16   
     Although several drawings have been described and illustrated in detail, it is to be understood that the same are intended by way of illustration and example. These examples are not intended to be exhaustive or to be limited to the precise form disclosed. Modifications and variations may well be apparent. For example, electrodes  24  and  26  may be located in positions other than on base member  12  (e.g., substrates  36 ,  38 ,  40 , and  42  or chamber layer and nozzle plates  44 ,  46 ,  48 , and  50 ). As another example, printhead assemblies  10 ,  124 ,  134  and/or  148  may utilize a single electrode or more than two electrodes. As a further example, printhead assemblies  10 ,  124 ,  134  and/or  148  may include a single die. As yet a further example, electrodes  24  and  26  may be utilized for additional purposes such as die warming, determining printhead to media spacing, and reducing printing composition puddling. 
     Additionally, reference to an element in the singular is not intended to mean one, unless explicitly so stated, but rather means at least one. Furthermore, unless specifically stated, any method elements are not limited to the sequence or order described and illustrated. Moreover, no element or component is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.