Patent Publication Number: US-2021162772-A1

Title: Image formation with electrostatic fixation

Description:
BACKGROUND 
     Modern printing techniques involve a wide variety of media, whether rigid or flexible, and for a wide range of purposes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a diagram including a side view schematically representing an example image formation device and/or method of image formation. 
         FIG. 1B  is a diagram including a side view schematically representing an example receiving portion for a fluid ejection device. 
         FIG. 1C  is a diagram including a side view schematically representing an example fluid ejection device removably inserted relative to an example receiving portion for a fluid ejection device. 
         FIG. 2  is a diagram including a side view schematically representing an example image formation device. 
         FIG. 3A  is a block diagram schematically representing an example first liquid removal portion. 
         FIG. 3B  is a block diagram schematically representing an example second liquid removal portion. 
         FIG. 4  is a diagram including a side view schematically representing an example image formation device. 
         FIG. 5  is a diagram including a side view schematically representing an example image formation device and/or method of image formation. 
         FIGS. 6A-6B  are a series of diagrams schematically representing example image formation on a media. 
         FIGS. 7A and 7B  are a block diagram schematically representing an example control portion and an example user interface, respectively. 
         FIG. 8  is a flow diagram schematically representing an example method of image formation. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise. 
     In some examples, an image formation device comprises a media supply, a first portion, and a second portion. The media supply is to supply a media along a travel path and to which a ground element is to be electrically connected. The first portion along the travel path is to receive droplets of ink particles within a dielectric carrier fluid onto the media to form at least a portion of an image on the media. The second portion is downstream along the travel path from the first portion and includes a charge generation portion to emit airborne charges to charge the ink particles to move, via attraction relative to the grounded media, through the carrier fluid toward the media to become electrostatically fixed on the media. 
     In some examples, the image formation device may sometimes be referred to as a printer or printing device. In some examples in which a media is supplied in a roll-to-roll arrangement or similar arrangements, the image formation device may sometimes be referred to as a web press and/or the media can be referred to as a media web. 
     At least some examples of the present disclosure are directed to forming an image directly on a media, such as without an intermediate transfer member. Accordingly, in some instances, the image formation may sometimes be referred to as occurring directly on the media. However, this does not necessarily exclude some examples in which an additive layer may be placed on the media prior to receiving ink particles (within a carrier fluid) onto the media. In some instances, the media also may sometimes be referred to as a non-transfer media to indicate that the media itself does not comprise a transfer member (e.g. transfer blanket, transfer drum) by which an ink image is to be later transferred to another media (e.g. paper or other material). In this regard, the media may sometimes also be referred to as a final media or a media product. In some such instances, the media may sometimes be referred to as product packaging media. 
     In some examples, the non-transfer media may sometimes be referred to as a non-transfer substrate, i.e. a substrate which does not act as a transfer member (e.g. a member by which ink is initially received and later transferred to a final substrate bearing an image). 
     In some examples, the media comprises a non-absorbing media. Stated differently, in some examples the media is made of a material which does not absorb liquids, such as a carrier fluid and/or other liquids in the droplets received on the media. In one aspect, in some such examples the non-absorbing media does not permit the liquids to penetrate, or does not permit significant penetration of the liquids, into the surface of the non-absorbing media. 
     Via the example arrangements, the example device and/or associated methods can print images on a non-absorbing media (or some other media) with minimal bleeding, dot smearing, etc. while permitting high quality color on color printing. Moreover, via these examples, image formation on a non-absorbing media (or some other media) can be performed with less time, less space, and less energy at least due to a significant reduction in drying time and capacity. These example arrangements stand in sharp contrast to other printing techniques, such as high coverage, aqueous-based step inkjet printing onto non-absorbing media for which bleeding, dot smearing, cockling, etc. may yield relatively lower quality results, as well as unacceptably high cost, longer times, etc. associated with drying. 
     In some examples, the first portion of the image formation device comprises a receiving portion to receive a fluid ejection device with the fluid ejection device to deliver the droplets of ink particles within the dielectric carrier fluid on the non-transfer media to form at least a portion of an image on the media. 
     In some examples, the fluid ejection device may comprise a drop-on-demand fluid ejection device to eject the droplets of ink particles (within the carrier fluid) onto the media. In some examples, the fluid ejection device comprises an inkjet printhead. In some examples, the inkjet printhead comprises a piezoelectric inkjet printhead. In some examples, the inkjet may comprise a thermal inkjet printhead. In some examples, the droplets may sometimes be referred to as being jetted onto the media. With this in mind, example image formation according to at least some examples of the present disclosure may sometimes be referred to as “jet-on-media” or “jet-on-substrate.” 
     In some examples, the fluid ejection device is to eject/deposit the dielectric carrier fluid on the media as a non-aqueous fluid. In some examples, the non-aqueous fluid comprises an isoparrafinic fluid or other oil-based liquid suitable for use as a dielectric carrier fluid. 
     These examples, and additional examples, will be further described below in association with at least  FIGS. 1-8 . 
       FIG. 1A  is a diagram including a side view schematically representing an example image formation device  10 . It will be further understood that  FIG. 1A  also may be viewed as schematically representing at least some aspects of an example method of image formation. 
     As shown in  FIG. 1A , in some examples an image formation device  10  comprises a media supply  22 , a first portion  30 , and a second portion  40 . The media supply  22  is to supply a media  24  along a travel path T and to which a ground element  29  is to be electrically connected. In some examples, media supply  22  may comprise a roll of media which is fed and moved along travel path T via support from an array of rollers to maintain tension and provide direction to media along travel path T. 
     In some examples, media  24  comprises a metallized layer or foil to which a ground element  29  is electrically connected. In some examples, an electrically conductive element separate from the media  24  is provided to contact the media  24  in order to implement grounding of the media  24 . 
     As shown in  FIG. 1A , in some examples the first portion  30  of image formation device  10  is located along and/or forms a portion of the travel path T, and is to receive droplets of ink particles  34  within a dielectric carrier fluid  32  on the media  24 . The depiction within the dashed lines A in  FIG. 1A  represents ink particles  34  and carrier fluid  32  after being received on media  24  to form at least a portion of an image on the media  24 . In some examples, the droplets from which ink particles  34  are formed may comprise pigments, dispersants, the carrier fluid  32 , and may comprise additives such as bonding polymers. 
     As further shown in  FIG. 1A , in some examples, the second portion  40  of image formation device  10  is located downstream along the travel path T from the first portion  30  and includes a charge generation portion  42  to emit airborne charges  44  to charge the ink particles  34 , as represented via the depiction in dashed lines B in  FIG. 1A . Once charged, the ink particles  34  move, via attraction relative to the grounded media  24 , through the carrier fluid  32  toward the media  24  to become electrostatically fixed on the media  24 , as represented via the depiction in dashed lines C in  FIG. 1A . 
     In some examples, the first portion  30  of image formation device  10  comprises a fluid ejection device to eject the droplets of ink particles  32  within the carrier fluid  32 .  FIG. 2  provides an illustration of one such example fluid ejection device  110 , which is positionable at a location spaced apart and above the media  24 . In some examples, the fluid ejection device  110  comprises a drop-on-demand fluid ejection device. In some examples, the drop-on-demand fluid ejection device comprises an inkjet printhead. In some examples, the inkjet printhead comprises a piezoelectric inkjet printhead. In some examples, the fluid ejection device  100  may comprise other types of inkjet printheads. 
     In some examples, as further described later in association with at least  FIG. 7A , among directing other and/or additional operations, a control portion  600  is instruct or to cause the fluid ejection device  110  to deliver the droplets of ink particles  34  within the dielectric carrier fluid  32  onto the media  24 , such as within the first portion along the travel path T of the media  24 . 
     As further shown in  FIG. 1B , in some examples the first portion  30  of image formation device  10  may comprise a first receiving portion  37  to removably receive the fluid ejection device  110 , such as in some examples in which the fluid ejection device  110  is removably insertable into the first receiving portion  37 . The first receiving portion  37  is sized, shaped, and positioned relative to media  24 , as well as relative to other components of image formation device  10 , such that upon removable insertion relative to first receiving portion  37  (as represented by arrow V), the fluid ejection device  110  is positioned to deliver (e.g. eject) the droplets of ink particles  34  and dielectric carrier fluid  32  onto media  24 , as shown in  FIG. 1C . In some such examples, the fluid ejection device  110  may comprise a consumable which is periodically replaceable due to wear, exhaustion of an ink supply, etc. In some such examples, the fluid ejection device  110  may be sold, supplied, shipped, etc. separately from the rest of image formation device  10  and then installed into the image formation device  10  upon preparation for use of image formation device  10  at a particular location. The first receiving portion  37  may sometimes be referred to as a first receptor. 
     With further reference to at least  FIGS. 1A, 1C, and 2A , in some examples, as part of ejecting droplets (e.g.  112  in  FIG. 2 ), the fluid ejection device  110  is to deposit the dielectric carrier fluid  32  on the media  24  as a non-aqueous liquid. In some examples, the non-aqueous liquid comprises an isoparrafinic fluid, which may be sold under the trade name ISOPAR. In some such examples, the non-aqueous liquid may comprise other oil-based liquids suitable for use as a dielectric carrier fluid. 
     With further reference to  FIG. 1A , in some examples the charge generation device  42  in the second portion  40  may comprise a corona, plasma element, or other charge generating element to generate a flow of charges. The generated charges may be negative or positive as desired. In some examples, the charge generation device  42  may comprise an ion head to produce a flow of ions as the charges. It will be understood that the term “charges” and the term “ions” may be used interchangeably to the extent that the respective “charges” or “ions” embody a negative charge or positive charge (as determined by device  42 ) which can become attached to the ink particles  34  to cause all of the charged ink particles to have a particular polarity, which will be attracted to ground. In some such examples, all or substantially all of the charged ink particles  34  will have a negative charge or alternatively all or substantially all of the charged ink particles  34  will have a positive charge. 
     Via such example arrangements, the charged ink particles  34  become electrostatically fixed on the media  24  in a location on the media  24  generally corresponding to the location (in an x-y orientation) at which they were initially received onto the media  24  in the first portion  30  of the image formation device  10 . Via such electrostatic fixation, the ink particles  34  will retain their position on media  24  even when other ink particles (e.g. different colors) are added later, excess liquid is physically removed, etc. It will be understood that while the ink particles may retain their position on media  24 , some amount of expansion of a dot (formed of ink particles) may occur after the ink particles  34  (within carrier fluid  32 ) are jetted onto media  24  and before they are electrostatically pinned. In some examples, the charge generation device  42  is spaced apart by a predetermined distance (e.g. downstream) from the location at which the droplets are received (or ejected) in order to delay the electrostatic fixation (per operation of charge generation device  42 ), which can increase a dot size on media  24 , which in turn may lower ink consumption. 
     In some examples, the ground element  29  may comprise an electrically conductive element in contact with a portion of the media  24 . In some examples, the electrically conductive element may comprise a roller or plate in rolling or slidable contact, respectively, with a portion of the media. In some examples, the ground element  29  is in contact with an edge or end of the media. In some examples, the electrically conductive element may take other forms, such as a brush or other structures. Accordingly, it will be understood that the ground element  29  is not limited to the particular location shown in  FIG. 1A . 
     In some examples, the media supply  22  of image formation device  10  is to supply the media  24  as a non-absorbing media. Stated differently, the media  24  is made of a material and/or coatings which hinder or prevent absorption of liquid, which stands in sharp contrast to some forms of media, such as paper, which may absorb liquid. The non-absorbing attributes of the media  24  may facilitate drying of the ink particles on the media at least because later removal of liquid from the media will not involve the time and expense of attempting to pull liquid out of the media (as occurs with absorbing media) and/or the time, space, and expense of providing heated air for extended periods of time to dry liquid in an absorptive media. 
     In some such examples, the non-absorptive media  24  may comprise other attributes, such as acting as a protective layer for items packaged within the media. Such items may comprise food or other sensitive items for which protection from moisture, light, air, etc. may be desired. 
     With this in mind, in some examples the media  24  may comprise a plastic media. In some examples, the media  24  may comprise polyethylene (PET) material, which may comprise a thickness on the order of about 10 microns. In some examples, the media  24  may comprise a biaxially oriented polypropylene (BOPP) material. In some examples, the media  24  may comprise a biaxially oriented polyethylene terephthalate (BOPET) polyester film, which may be sold under trade name Mylar in some instances. In some examples, the media  24  may comprise other types of materials which provide at least some of the features and attributes as described throughout the examples of the present disclosure. For examples, the media  24  or portions of media  24  may comprise a metallized foil or foil material, among other types of materials. 
       FIG. 2  is a diagram including a side view schematically representing an example image formation device  100 . In some examples, device  100  comprises at least some of substantially the same features and attributes as device  10  previously described in association with  FIG. 1A . It will be further understood that  FIG. 2  also may be viewed as schematically representing at least some aspects of an example method of image formation. 
     As shown in  FIG. 2 , the image formation device  100  comprises a media supply  22 , first portion  30 , and second portion  40  having substantially the same features and attributes as in device  10  in  FIG. 1A . In some examples, fluid ejection device  110  in the first portion  30  may comprise a permanent component of image formation device  10 , which is sold, shipped, and/or supplied, etc. as part of image formation device  10 . It will be understood that such “permanent” components may be removed for repair, upgrade, etc. as appropriate. 
     However, in some examples, first portion  30  may comprise a first receiving portion  37  as shown in  FIG. 1B  to removably receive fluid ejection device  110 , as previously described in association with  FIGS. 1B-1C , such as in instances when fluid ejection device  110  may comprise a consumable, be separately sold, etc. 
     However, as shown in  FIG. 2 , in some examples image formation device  100  comprises a third portion  150 , including a first liquid removal portion  152 , downstream along the travel path T from the charge generation portion  42  (in second portion  40 ) to remove at least a portion of the carrier fluid  32  from the media  24 . In some examples, the first liquid removal portion  152  is to remove the carrier fluid  32  without heating the fluid  32  at all or without heating the carrier fluid  32  above a predetermined threshold. In some instances, such liquid removal may sometimes be referred to as cold liquid removal by which the liquid is removed at relatively cool temperatures, at least as compared to high heat drying techniques. Accordingly, in some such examples, a mechanical element (e.g. squeegee roller) of the first liquid removal portion  152  may slightly heat the carrier fluid  32  and/or other liquid without using heat as a primary mechanism to remove the carrier fluid  32  from the ink particles  34  on media  24 . 
     As further shown in  FIG. 3A , the first liquid removal portion  152  may comprise a squeegee  202  and/or roller  204  or other mechanical structure to remove the carrier fluid  32  (and any other liquid) from the surface of media  24 . In some examples, the electrostatically fixed (e.g. pinned) charged ink particles  34  remain fixed in their respective locations on media  24  during this physical removal of liquid at least because the electrostatic fixation forces are greater than the shear forces exhibited via the tool(s) used to mechanically remove the carrier fluid  32 . In this third portion  150 , in some examples, at least  80  percent of the jetted carrier fluid  32  on media  24  is removed. In some examples, at least  90  percent of the jetted carrier fluid  32  is removed. In some examples, at least  95  percent of the jetted carrier fluid  32  is removed. However, in some examples, first liquid removal portion  152  may remove at least  50  percent of total liquid, which includes the carrier fluid  32 , from media  24 . 
     As further shown in  FIG. 2 , in some examples the device  100  may further comprise a second liquid removal portion  162  (in fourth portion  160 ) downstream from the first liquid removal portion  152 . The second liquid removal portion  162  acts to remove any liquid not removed via first liquid removal portion  152  (in third portion  150 ) and thereby result in dried ink particles  34  on the media  24 , as represented via the depictions in dashed lines D and E in  FIG. 2 , or as later shown in  FIG. 6D . 
     As later shown in  FIG. 3B , in some examples the second liquid removal portion  162  may comprise a heated air element  222  to direct heated air onto at least the carrier fluid  32  and media  24 . In some examples, the heated air is controlled to maintain the ink particles  34 , media  24 , etc. at a temperature below 60 degrees C., which may prevent deformation of media  24  such as cockling, etc. 
     In some examples, the second liquid removal portion  162  may comprise a radiation element  232  to direct at least one of infrared (IR) radiation and ultraviolet (UV) radiation onto the liquid  32  and media  24  to eliminate liquid remaining after operation of the first liquid removal portion  152 . In some examples, the second liquid removal portion  162  may sometimes be referred to as an energy transfer mechanism or structure by which energy is transferred to the liquid  32 , ink particles  34 , and media  24  in order to dry the ink particles  34  and/or media  24 . 
     As further shown in  FIG. 2 , in some examples image formation device  100  may further comprise a finish treatment element  172  (in fifth portion  170 ) downstream from the second liquid removal portion  162  (in fourth portion  160 ) to add a finish layer  174  on top of the ink particles  34  electrostatically fixed on the media  24 . The finish layer  174  may enhance adhesion of the ink particles  34  to the media  24 , protect the image formed by the ink particles  34 , etc. The material applied as a finish layer  174  may be ultraviolet curable, a solvent, water-based, etc. In some examples, the material applied as a finish layer  174  may be a sealant, adhesion promoter, varnish, and the like, as well as various combinations of such finishing materials. In some examples, the finish layer may be implemented as later described in association with at least  FIG. 6D . 
     In some examples, the finish layer  174  is added via finish treatment element  172  prior to operation of the second liquid removal portion  160 . Accordingly, it will be understood that in some examples, the sequence of operation of some portions (e.g.  150 ,  160 ,  170 ) of image formation device  10  may be re-arranged in some instances. Moreover, it will be understood that in some examples the labeling of the various portions as first, second, third, fourth, fifth portions (e.g.  30 ,  40 ,  150 ,  160 ,  170 ) does not necessarily reflect an absolute ordering or position of the respective portions along the travel path T. Moreover, such labeling of different portions also does not necessarily represent the existence of structural barriers or separation elements between adjacent portions of the image formation device  10 ,  100 . Furthermore, in some examples, the components of the image formation device  100  may be organized into a fewer or greater number of portions than represented in  FIG. 2 . 
     As further shown in  FIG. 2 , in some examples media supply  22  may comprise a plurality of rollers  23 ,  25 ,  27  to support and guide media  24  along travel path T. While not shown for illustrative simplicity, additional rollers may be present to support media  24  throughout each of the different portions of an image formation device. In some examples, these arrangements of rollers may comprise a roll-to-roll arrangement. 
       FIG. 4  is a diagram including a side view schematically representing an example image formation device  200 . In some examples, the example image formation device  200  comprises at least some of substantially the same features as the example image formation devices  10  ( FIG. 1A ),  10  ( FIGS. 1B-1C ), and/or  100  ( FIGS. 2, 3A-3B ) with similar reference numerals denoting similar elements. 
     In some examples, example image formation device  200  comprises additional elements such as an example primer element  210  and/or a finalizing element  182  in a sixth portion  180 . It will be further understood that  FIG. 4  also may be viewed as schematically representing at least some aspects of an example method of image formation. 
     As shown in  FIG. 4 , the primer element  212  forms part of a preliminary portion  210  (e.g. seventh portion) which is upstream from (e.g. precedes) the first portion  30  and which is provided to deposit a primer layer (represented via dashed box P). In some examples, the primer layer comprises material(s) which prepare the surface of media  24  to receive droplets of ink particles  34  within the carrier fluid  32  in the first portion  30 . Some example primer materials may comprise a resin, dissolved resin, binding polymers, or adhesion promoting materials. 
     As further shown in  FIG. 4 , the example finalizing element  182  in sixth portion  180  of image formation device  200  is downstream from the finish treatment element  172  (in fifth portion  170 ) of image formation device  200 . In some examples, the finalizing element  182  may provide heated air, ultraviolet (UV) radiation, infrared (IR) radiation, or similar modalities. Via at least such modalities, the finalizing element  182  may act to remove liquid from the ink particles  34  (and/or from media  24 ) and/or may act to induce or cause curing of the finishing layer  174  added via the finish treatment element  172  in the fifth portion  170 . 
       FIG. 5  is a diagram including a side view schematically representing an example image formation device  300 . In some examples, the image formation device  300  comprises a media supply and a series of stations arranged along the travel path of the media in which each station is to provide one color ink of a plurality of different color inks onto the media. It will be further understood that  FIG. 5  also may be viewed as schematically representing at least some aspects of an example method of image formation. 
     In some examples, the image formation device  300  comprises at least some of substantially the same features and attributes as the devices  100 ,  200 , etc., and portions, components, thereof, as previously described in association with  FIGS. 1A-4 . However, in image formation device  300  a series of image formation stations  360 ,  370 , etc. is provided along a travel path of the media  24 . In some examples, each different image formation station  360 ,  370 , etc. provides for at least partial formation of an image on media  24  by a respectively different color ink. Stated differently, the different stations apply different color inks such that a composite of the differently colored applied inks forms a complete image on media  24  as desired. In some examples, the different color inks correspond to the different colors of a color separation scheme, such as Cyan (C), Magenta (M), Yellow (Y), and black (K) wherein each different color is applied separately as a layer to the media  24  as media  24  moves along travel path T. 
     As shown in  FIG. 5 , each station  360 ,  370 , etc. may comprise at least a first portion  30  and a second portion  40  having substantially the same features as previously described. In some examples, each station may comprise additional portions, such as but not limited to, portions  150 ,  160 ,  170  as described in association with at least  FIG. 2 . 
     As further shown in  FIG. 5 , the image formation device  300  may comprise additional stations, and as such, the black circles III, IV represent further stations like stations  360 ,  370  for applying additional different color inks onto media  24 . In some examples, the additional stations may comprise a fewer number or a greater number of additional stations (e.g. III, IV) than shown in  FIG. 5 . 
       FIGS. 6A-6B  are a series of diagrams, each including a side view, schematically representing some aspects of example image formation on a media  424  in association with an example image formation device and/or an example method of image formation. In some examples, the image formation may be implemented via one of the example devices  100 ,  200 , etc. and/or methods, as previously described in association with at least  FIGS. 1A-5  and/or via method  500  in association with  FIG. 8 . 
     In one such example, the diagram  400  in  FIG. 6A  schematically represents a state of a media  424  after passage through the second portion  40  of an image formation device (e.g.  FIGS. 1A-2B ), but prior to passage along the travel path T through a third or fourth portions (e.g.  150 ,  160 ) for liquid removal. As such,  FIG. 6A  depicts charged particles  434  as electrostatically fixed on media  424  with charges  444  remaining on/with the ink particles  434  and with carrier fluid  432  still present on media  424 . As further shown in  FIG. 6A , extra charges  445  are present on a surface of a white ink layer  455  in areas in which no ink particles are present. Discharge of these charges  445  is further described later with respect to the role of white ink layer  455 . 
     In some examples, media  424  comprises a flexible packaging material. In some such examples, the flexible packaging material may comprise a food packaging material, such as for forming a wrapper, bag, sheet, cover, etc. As previously mentioned for at least some examples, the flexible packaging materials may comprise a non-absorptive media. 
     In at least some examples associated with  FIGS. 6A-6D , the media  24  comprises a generally uniform white ink layer  455  which is present prior to applying the different color inks to form the intended image on the media  424 . Among other features and attributes, the white color of ink layer  455  provides a suitable neutral background against which images may be formed on media  424 , thereby enhancing clarity, sharpness, etc. of the image. In some examples, the ink layer  455  may comprise a color other than white but which is suitable in providing a generally uniform background appearance on media  424 . 
     In some such examples, a media supply (e.g.  22  in  FIGS. 1A-2B, 5 ) is to supply the media  424  already having the white ink layer  455  and onto which the ink particles  434  (e.g.  34  in  FIGS. 1A-5 ) are to be electrostatically fixed. 
     However, in some examples, the media  424  may initially omit a white ink layer  455  and instead, the white ink layer  455  is added via a first portion (e.g.  20 ) of a first station via a fluid ejection device (e.g.  110  in  FIG. 2 ) and then other color ink layers are added to the media  424  via subsequent image formation stations, such as shown in at least  FIG. 5 . In some such examples, the white color ink comprising the layer  455  may sometimes be implemented as a SPOT color ink. 
     As represented via directional arrows R shown in  FIG. 6A , the white ink layer  455  may also facilitate discharge of background charges  445  (to ground  29  via layer  455 ), i.e. those charges emitted by charge generation portion  162  which do not become bound to an ink particle  34 ,  434  or which are otherwise not dissipated. In some examples, the white ink layer  455  may comprise a conductivity below 10 10  Ohm CM, which is suitable to allow discharge of background charges to ground, thereby enabling electrostatic fixation of a second color ink particles  435  shown in  FIGS. 6C, 6D . 
     Via the absence of charges  445  at the surface of white ink layer  455 , the diagram  450  in  FIG. 6B  depicts the discharge of the background charges  455  initially present from charging ink particles  434  as shown in  FIG. 6A . 
     In one aspect, the electrical properties (e.g. conductivity and dielectric thickness) of the white ink layer  455  may be tuned to allow electrostatic fixation of the ink particles  434  for a long enough period of time (e.g. on the order of  100  milliseconds) to effectuate the electrostatic fixation while still being quick enough to avoid building a voltage that would be too high so as to interfere with electrostatic fixation of the next color ink in forming an image on media  424 . 
     As further shown in  FIG. 6A , in some examples the media  424  may have a thickness T 2  on the order of 10 microns (e.g. PET), 20 microns (e.g. BOPP) while the white ink layer  455  may comprise a thickness T 3  on the order of a few microns, such as about 1 to 10 microns.  FIG. 6A  also illustrates that, upon initially receiving droplets from a fluid ejection device (e.g.  110  in  FIG. 2 ) onto media  424  (and white ink layer  455 ), an appreciable volume of carrier fluid  432  (with ink particles  434  therein) accumulates. In some such examples, a thickness T 1  of the carrier fluid  432  for one such layer may be on the order of 10 microns, while the accumulated carrier fluid  432  for multiple layers (e.g. 3) may be on the order of about 30 microns. As shown later in the diagram  460  in  FIG. 6C , the accumulation of carrier fluid  432  for two layers of color ink being received on media  424  may be represented as a thickness T 5 , which may be on the order of about 20 microns. 
     As further shown in  FIG. 6A , in some examples a metallic layer  427  may serve as an outer layer (e.g. upper layer) of media  424 , and may comprise a thickness T 4  on the order of tens of nanometers and up to a few microns. In some examples, the metallic layer  427  may form part of media  424  when media  424  comprises a flexible product packaging used to protect food or other sensitive contents. The metallic layer  427  may act as a moisture and oxygen barrier to protect the safety and freshness of the food or to protect other attributes of sensitive non-food contents. 
     As further shown in  FIG. 6A , a ground element  429  is electrically connected to the metallic layer  427  of media  424  to ground media  424  to attract charged ink particles  434 . As previously mentioned in association with at least  FIGS. 1A-2B , other portions of media  424  may provide an electrically conductive element to which ground element  429  may be electrically connected. 
     In some examples, after the pigments (e.g. ink particles  434 ) are separated and electrostatically fixed (e.g. pinned), chemical forces may develop to further facilitate the fixation of ink particles  434  to media  424  (via white ink layer  455 ). In one aspect, the existence of and/or strength of such chemical forces depend on at least the pigment type, pigment coating, polymers/additives to the ink, etc. 
       FIG. 6C  illustrates another point in time during formation of an image on media  424 , such as after droplets of ink particles  435  of a second color ink (within some carrier fluid  432 ) have been jetted onto the media  424  (on white ink layer  455 ), and after charges have been applied via a charge generation device (e.g.  42  in  FIGS. 1A-2B, 5 ) to the second color ink particles  435 . As shown in  FIG. 6C , some of the second color ink particles  435  cover, overlap, and/or intermix with some of the first color ink particles  434 . In a manner similar to  FIG. 6A , it can be seen in  FIG. 6C  that background charges  445  are present but may be discharged in a manner similar to that described in association with  FIGS. 6A-6B . 
     Moreover, the view in  FIG. 6C  also depicts a greater thickness (T 5 ) of carrier fluid  432  on top of the white ink layer  455  and media  424 , which corresponds to the additional carrier fluid  432  in which the second color ink particles  435  were delivered when jetted onto white ink layer  455  and media  424 . 
     While not directly represented in  FIGS. 6A-6D , it will be understood that after all the different color ink particles are deposited on white ink layer  455  to form a desired image on media  424 , excess carrier fluid  432  is removed mechanically (e.g. via first liquid removal portion  152 ) and via application of energy (e.g. via second liquid removal portion  162 ), such as shown in at least  FIGS. 2-4 . 
     With this in mind, as shown in the diagram in  FIG. 6D , after the removal of liquid (e.g. carrier fluid  432 ) and drying, a finish layer  471  is applied on top of the dried, ink particles  434 ,  435 , etc. (in the form of an image) and a cover layer  473  of a protective material (e.g. Mylar, PET, etc.) is laminated or otherwise secured onto the finish layer  471 . In one example, once sealed the completed assembly  470  may be used in the flexible packaging market. In some examples, such flexible packaging may comprise food packaging. In some such examples of food packaging, the media layer  424  of completed assembly  470  may face or enclose the food contained with the package formed from completed assembly  470 . Meanwhile, the cover layer  472  may face or be exposed to the consumer, user, etc. 
     In some such examples, this additional outer cover layer  473  can be transparent. In some examples, the finish layer  471  comprises an adhesive to facilitate securing the cover layer  473 . 
     However, with further reference to at least  FIG. 6D , in some examples the finish layer  471  may be applied on top of the dried, ink particles  434 ,  435  without adding cover layer  473  such that finish layer  471  acts as a protective element for ink particles  434 ,  435 . In some examples, the finish layer  471  may comprise a sealant, adhesive, varnish, and the like, such as but not limited to at least some of substantially the same features and attributes as the finish layer(s) provided via finish treatment element  172 , as previously described in association with at least  FIGS. 2 and 4 . In some examples, the finish layer  471  is finalized via curing (e.g. UV, IR) or heated air in order to dry, fix, cross-link, and/or solidify the finish layer  471  with the ink particles  434 ,  435  on media  424 . In some examples, such finalizing may be performed via a finalizing element  182 , such as described in association with  FIG. 4 . 
     In some examples, the finish layer  471  comprises a thickness T 6  while the cover layer  473  comprises a thickness T 7 . 
     In some examples, the finish layer  471  comprises the final or outermost layer of a print medium, which may be available to consumers or other users and/or which is suitable for contact with handling rollers, other media, etc. However, in some examples, the presence of the finish layer  471  does not preclude the deposition of additional layers and/or other treatments. 
       FIG. 7A  is a block diagram schematically representing an example control portion  600 . In some examples, control portion  600  provides one example implementation of a control portion forming a part of, implementing, and/or generally managing the example image formation devices  10 ,  100 ,  200 , as well as the particular portions, elements, devices, user interface, instructions, engines, and/or methods, as described throughout examples of the present disclosure in association with  FIGS. 1A-6D and 8 . 
     In some examples, control portion  600  includes a controller  602  and a memory  610 . In general terms, controller  602  of control portion  600  comprises at least one processor  604  and associated memories. The controller  602  is electrically couplable to, and in communication with, memory  610  to generate control signals to direct operation of at least some the image formation devices, various portions and elements of the image formation devices, fluid ejection devices, charge generation elements, liquid removal portions, finishing treatment elements, user interfaces, instructions, engines, functions, and/or methods, as described throughout examples of the present disclosure. In some examples, these generated control signals include, but are not limited to, employing instructions  611  stored in memory  610  to at least direct and manage depositing droplets of ink particles and carrier fluid to form an image on a media, directing charges onto ink particles, removing liquids, applying finish treatments, etc. as described throughout the examples of the present disclosure in association with  FIGS. 1-6D and 8 . In some instances, the controller  602  or control portion  600  may sometimes be referred to as being programmed to perform the above-identified actions, functions, etc. In some examples, at least some of the stored instructions  611  are implemented as a, or may be referred to as, a print engine. 
     In response to or based upon commands received via a user interface (e.g. user interface  620  in  FIG. 7B ) and/or via machine readable instructions, controller  602  generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller  602  is embodied in a general purpose computing device while in some examples, controller  602  is incorporated into or associated with at least some of the image formation devices, portions or elements along the travel path, fluid ejection devices, charge generation elements, liquid removal portions, finish treatment elements, user interfaces, instructions, engines, functions, and/or methods, etc. as described throughout examples of the present disclosure. 
     For purposes of this application, in reference to the controller  602 , the term “processor” shall mean a presently developed or future developed processor (or processing resources) that executes sequences of machine readable instructions contained in a memory. In some examples, execution of the sequences of machine readable instructions, such as those provided via memory  610  of control portion  600  cause the processor to perform the above-identified actions, such as operating controller  602  to implement the formation of an image as generally described in (or consistent with) at least some examples of the present disclosure. The machine readable instructions may be loaded in a random access memory (RAM) for execution by the processor from their stored location in a read only memory (ROM), a mass storage device, or some other persistent storage (e.g., non-transitory tangible medium or non-volatile tangible medium), as represented by memory  610 . In some examples, memory  610  comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller  602 . In other examples, hard wired circuitry may be used in place of or in combination with machine readable instructions to implement the functions described. For example, controller  602  may be embodied as part of at least one application-specific integrated circuit (ASIC). In at least some examples, the controller  602  is not limited to any specific combination of hardware circuitry and machine readable instructions, nor limited to any particular source for the machine readable instructions executed by the controller  602 . 
     In some examples, control portion  600  may be entirely implemented within or by a stand-alone device. 
     In some examples, the control portion  600  may be partially implemented in one of the image formation devices and partially implemented in a computing resource separate from, and independent of, the image formation devices but in communication with the image formation devices. For instance, in some examples control portion  600  may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion  600  may be distributed or apportioned among multiple devices or resources such as among a server, an image formation device, and/or a user interface. 
     In some examples, control portion  600  includes, and/or is in communication with, a user interface  620  as shown in  FIG. 7B . In some examples, user interface  620  comprises a user interface or other display that provides for the simultaneous display, activation, and/or operation of at least some of the image formation devices, portions, elements, user interfaces, instructions, engines, functions, and/or methods, etc. as described in association with  FIGS. 1-6D and 8 . In some examples, at least some portions or aspects of the user interface  620  are provided via a graphical user interface (GUI), and may comprise a display  624  and input  622 . 
       FIG. 8  is a flow diagram schematically representing an example method. In some examples, method  700  may be performed via at least some of the same or substantially the same devices, portions, stations, elements, control portion, user interface, etc. as previously described in association with  FIGS. 1A-7B . In some examples, method  500  may be performed via at least some devices, portions, stations, elements, control portion, user interface, etc. other than those previously described in association with  FIGS. 1A-7B . 
     In some examples, as shown at  702  in  FIG. 8 , method  700  comprises selectively depositing, via a fluid ejection device, droplets of ink particles within a dielectric carrier fluid onto a non-absorbing, non-transfer media moving along a travel path. As shown in  FIG. 8  at  704 , in some examples method  700  comprises electrically grounding, via a ground element, the media. As shown in  FIG. 8  at  706 , in some examples method  700  comprises directing charges onto the ink particles within deposited droplets on the media to induce movement of the charged ink particles, via attraction relative to the grounded media, through the deposited carrier fluid to electrostatically fix the charged ink particles in contact relative to an outer surface of the non-transfer media. 
     Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.