Patent Description:
Document <CIT> discloses an image formation device and a method of image formation comprising means for electroosmotic liquid removal.

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 invention which is defined by the appended claims. The following detailed description, therefore, is not to be taken in a limiting sense.

In some examples, an image formation device comprises a fluid ejection device and a first porous element. The fluid ejection device is located along a travel path of a substrate to deposit droplets of ink particles within a liquid carrier onto the substrate to at least partially form an image on the substrate. The first porous element is located downstream along the travel path from the fluid ejection device to be in contact against the substrate to remove, via electroosmotic flow through the first porous element, at least a portion of the liquid carrier from the substrate. In some such examples, the support is to support movement of a substrate along a travel path. In some such examples, the area of contact between the first porous element and the substrate may sometimes be referred to as a first liquid removal zone or first contact zone.

According to the invention, a second porous element engages the first porous element at a location remote (e.g. separated from) the first contact zone at which the first porous element engages the substrate. The second porous element, via electroosmotic flow through both the first and second porous elements, removes liquid from the first porous element to dry the first porous element for further, later engagement with the substrate. In some such examples, the area of contact between the second porous element and the first porous element may sometimes be referred to as a second liquid removal zone or second contact zone. As noted above, the second liquid removal zone is located separate from (e.g. remote) the first liquid removal zone, such as the second liquid removal zone being downstream from the area of contact between the first porous element and the substrate.

In some examples, the liquid carrier may comprise an aqueous-based liquid carrier.

In some such examples, large volumes of the liquid carrier may be rapidly removed from the substrate (after image formation via ink particles) without costly heating or evaporation mechanisms as a primary means of removing such liquid. Moreover, in some examples the removal of liquid via engagement of the first porous element relative to the substrate may be implemented without mechanical elements (at the site of engagement) such as blades, squeegee rollers, while still achieving desirable speed and/or volume of liquid removal of aqueous-based liquids from the substrate.

These examples, and additional examples, are further described below in association with at least <FIG>.

<FIG> is a diagram including side views schematically representing at least some aspects of an example image formation device <NUM>. As shown in <FIG>, a support <NUM> supports a substrate <NUM> for movement along a travel path T. The support <NUM> may take various forms such as, but not limited to, a rotatable drum or a plurality of rollers, as later described in association with at least <FIG>, respectively.

As further shown in <FIG>, in some examples the image formation device <NUM> comprises a fluid ejection device <NUM> and a first porous element <NUM>. The fluid ejection device <NUM> is located along the travel path T to deposit droplets <NUM> of ink particles <NUM> within a liquid carrier <NUM> onto the substrate <NUM> to at least partially form an image on the substrate <NUM>, as represented within dashed box A.

In some examples, the first porous element <NUM> is located downstream along the travel path T from the fluid ejection device <NUM>. As shown in <FIG>, among other features the first porous element <NUM> is in contact against the substrate <NUM> to remove, via electroosmosis flow through the first porous element <NUM>, at least a portion of the liquid carrier <NUM> from the substrate <NUM>.

In some such examples, the contact between the first porous element <NUM> and the substrate <NUM> may comprise moving contact, such as rolling contact between the belt <NUM> and the substrate <NUM>. However, in some examples, the moving contact may comprise sliding contact.

In some examples, the first porous element <NUM> may be considered to be part of a, and/or sometimes referred to as, a liquid removal arrangement.

In some examples, the fluid ejection device <NUM> 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 <NUM> may comprise other types of inkjet printheads. 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, at least some of the aspects and/or implementations of image formation according to at least some examples of the present disclosure may sometimes be referred to as "jet-on-media", "jet-on-substrate", "jet-on-blanket", "offjet printing", and the like.

In some examples, the liquid carrier <NUM> may also comprise certain additives to increase a conductivity of the ink mixture deposited as droplets <NUM> from the fluid ejection device <NUM>. In some examples, such increased conductivity may in turn enhance electroosmotic flow of liquid (e.g. liquid carrier <NUM>) to remove liquid from the substrate <NUM> and/or from the first porous element (via a second porous element per later examples). In some such examples, the conductive additives may comprise solutions of buffers, such as phosphate buffer, borate buffer, or other electrolytes based on lithium, sodium, potassium, calcium, magnesium, chloride, perchlorate, phosphate, carbonate, sulphate, nitrate.

It will be understood that in some examples, the fluid ejection device <NUM> may comprise a permanent component of image formation device <NUM>, which is sold, shipped, and/or supplied, etc. as part of image formation device <NUM>. It will be understood that such "permanent" components may be removed for repair, upgrade, etc. as appropriate. However, in some examples, fluid ejection device <NUM> may be removably received, such as in instances when fluid ejection device <NUM> may comprise a consumable, be separately sold, etc..

In some examples, the liquid carrier <NUM> may comprise an aqueous liquid carrier.

However, in some examples, the liquid carrier <NUM> may comprise a non-aqueous liquid carrier, such as in the example image formation devices described in association with at least <FIG>. In some such examples, when non-aqueous dielectric inks are used, and when electrostatic fixation (i.e. pinning) of ink particles <NUM> is implemented as shown in <FIG>, an electrically conductive element separate from the substrate <NUM> is provided to contact the substrate <NUM> in order to implement grounding of the substrate <NUM>.

In some examples, substrate <NUM> comprises a metallized layer or foil.

However, in some examples, the substrate <NUM> is not metallized and comprises no conductive layer.

In some examples, the substrate <NUM> comprises a non-absorbing material, non-absorbing coating, and/or non-absorbing properties. Accordingly, in some examples the substrate <NUM> is made of a material which hinders or prevents absorption of liquids, such as a liquid carrier <NUM> and/or other liquids in the droplets received on the medium. In one aspect, in some such examples the non-absorbing medium does not permit the liquids to penetrate, or does not permit significant penetration of the liquids, into the surface of the non-absorbing medium.

The non-absorbing example implementations of the substrate <NUM> stands in sharp contrast to some forms of media, such as paper, which may absorb liquid. The non-absorbing attributes of the substrate <NUM> 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.

Via the above-described example arrangements in which a first porous element is used to remove a liquid carrier from a substrate, the example device and/or associated methods can print images on a non-absorbing medium (or some other medium) with minimal bleeding, dot smearing, etc. while permitting high quality color on color printing. Moreover, via these examples employing electroosmotic flow-based liquid removal, image formation on a non-absorbing medium (or some other medium) 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 (those lacking such electroosmotic flow-based liquid removal), such as high coverage, aqueous-based inkjet printing utilizing roller-to-roller nip based liquid removal (or similar mechanical elements) which may not adequately remove the liquid unless higher cost, lengthy drying is applied.

In some such examples, the non-absorptive substrate <NUM> 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 substrate <NUM> may comprise a plastic media. In some examples, the substrate <NUM> may comprise polyethylene (PET) material, which may comprise a thickness on the order of about <NUM> microns. In some examples, the substrate <NUM> may comprise a biaxially oriented polypropylene (BOPP) material. In some examples, the substrate <NUM> 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 substrate <NUM> 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 substrate <NUM> or portions of substrate <NUM> may comprise a metallized foil or foil material, among other types of materials.

In some examples, substrate <NUM> 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 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 print medium 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 print medium, such as without an intermediate transfer member. Accordingly, in some instances, the image formation may sometimes be referred to as occurring directly on substrate <NUM>, which may sometimes be referred to the print medium in such instances. However, this does not necessarily exclude some examples in which an additive layer may be placed on the print medium prior to receiving ink particles (within a carrier fluid) onto the print medium. In some instances, the print medium also may sometimes be referred to as a non-transfer medium to indicate that the medium 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 print medium (e.g. paper or other material). In this regard, the print medium may sometimes also be referred to as a final medium or a media product. In some such instances, the medium may sometimes be referred to as product packaging medium.

In some examples, the substrate <NUM> 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). Rather, in some such examples, the substrate <NUM> may comprise a final print medium such that the printing or image formation may sometimes be referred as being direct printing because no intermediate transfer member is utilized as part of the printing process.

In some examples, the substrate <NUM> comprises an intermediate transfer member, such as (but not limited to) the example image formation device <NUM> further described in association with at least <FIG> and <FIG>. In some instances, such an intermediate transfer member may be referred to as a blanket.

As shown in <FIG>, in some examples, there are no features, elements, etc. (along the travel path T) located between the fluid ejection device <NUM> and the first porous element <NUM>. However, as schematically represented by the black dots X, in some examples the image formation device <NUM> may comprise additional features, elements, etc. located along the travel path T between the fluid ejection device <NUM> and the first porous element <NUM>. For instance, in some examples the image formation device <NUM> may comprise a charge emitter (e.g. located after the fluid ejection device <NUM>) to emit electrostatic charges onto the deposited droplets <NUM> to cause electrostatic migration toward, and electrostatic fixation of, the ink particles <NUM> relative to the substrate, as further described in association with at least <FIG>.

<FIG> is a diagram <NUM> including a side view schematically representing an example first porous element <NUM> in the form of an outer portion <NUM> of a rotatable drum <NUM>. In some such examples, the first porous element <NUM> comprises at least some of substantially the same features and attributes as first porous element <NUM> in <FIG>. Accordingly, in some examples, the outer portion <NUM> and/or rotatable drum <NUM> comprises a conductive material and/or a conductive member to facilitate the electroosmotic flow through the outer portion <NUM> (acting a first porous element) to remove liquid from a substrate, such as substrate <NUM> in <FIG>. Further details regarding such an example first porous element <NUM>, arranged as an outer portion <NUM> of a rotatable drum <NUM>, are further described in association with at least <FIG>. Moreover, in some examples, the configuration shown in <FIG> may be applicable to at least some aspects of a second porous element, which may comprise an outer portion of a rotatable drum, as further described later in association with at least <FIG> and <FIG>.

<FIG> is a diagram <NUM> including a side view schematically representing an example first porous element <NUM> in the form of a belt <NUM> being supported by, and rotating about, a first roller <NUM>. In some such examples, the first porous element <NUM> comprises at least some of substantially the same features and attributes as first porous element <NUM> in <FIG>. Accordingly, in some examples, the first roller <NUM> comprises a conductive material and/or a conductive member to facilitate the electroosmotic flow through the belt <NUM> (acting as a first porous element) to remove liquid from a substrate, such as substrate <NUM> in <FIG>. Further details regarding such example first porous elements <NUM>, arranged as a belt <NUM>, are further described in association with at least <FIG> and <FIG>.

<FIG> is a diagram <NUM> including a side view schematically representing an example liquid removal arrangement <NUM> for removing liquid from a substrate via electroosmotic flow of liquid through an example first porous element <NUM>. In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the features and attributes of, and/or comprises an example implementation of, the liquid removal arrangement of <FIG>. As shown in <FIG>, the liquid removal arrangement <NUM> comprises a first porous element <NUM> in moving contact against a substrate <NUM> and an electric field (represented via arrows EF) being applied from the substrate <NUM> through the first porous element <NUM> to cause electroosmotic flow of liquid <NUM> through the first porous element <NUM> to remove liquid from the substrate <NUM> while not disturbing the deposited ink particles <NUM> on the substrate <NUM>. It will be understood that the electric field is generally uniform along length of the first porous element <NUM> commensurate with a length of the substrate <NUM> in contact with the first porous element <NUM>.

In particular, as shown in <FIG>, the first porous element <NUM> is supported by support <NUM>, which may comprise a conductive material and/or a conductive member (as represented by identifier C). Support <NUM> may take the form of a roller (e.g. <NUM> in <FIG>), a rotatable drum (e.g. <NUM> in <FIG>), or other structure. Similarly, in some examples the substrate <NUM> is supported by support <NUM>, which may comprise a conductive material and/or a conductive member (as represented by identifier C). Support <NUM> may take the form of a roller (e.g. <NUM> in <FIG>), a rotatable drum (e.g. <NUM> in <FIG>), or other structure.

In some examples, the support <NUM> and/or the substrate <NUM> may be grounded per a ground element (GND) which may form part of the support <NUM> and/or substrate <NUM> and/or which may be connected to the support <NUM> and/or substrate <NUM>.

As further shown in <FIG>, the liquid removal arrangement <NUM> comprises an electric field applicator <NUM> by which the electric field (EF) may be established from support <NUM> (exhibiting positive charges <NUM>), through substrate <NUM> and through first porous element <NUM>, to support <NUM> (exhibiting negative charges <NUM>). Further details regarding the electric field and/or electroosmotic flow are described in association with at least <FIG>.

Via this arrangement <NUM>, electroosmotic flow will occur through the first porous element <NUM> to cause removal of liquid carrier <NUM> from substrate <NUM>. It will be understood that in some examples the first porous element <NUM> comprises a structure and/or materials adapted to cause capillary flow of liquids through the first porous element <NUM> such that the application of the electric field causes electroosmotic flow (e.g. pumping action) to augment the capillary flow. In some such examples, the structure and/or the materials forming the first porous element <NUM> may induce or cause adsorption of liquids, such as a liquid carrier <NUM>. Accordingly, in some instances, the first porous element <NUM> may sometimes be referred to as an adsorptive porous element. At least some of these details are described further below in association with at least <FIG>.

<FIG> is a diagram including a side view schematically representing an example first porous element <NUM> including a plurality of channels <NUM>. In some examples, the first porous element <NUM> comprises one example implementation of the first porous element <NUM>, <NUM>, <NUM> as previously described in association with <FIG> and/or of later described example first porous elements and/or second porous elements. In general terms, the first porous element <NUM> may comprise a wide variety of materials and/or structures to induce a liquid to flow through the first porous element <NUM>, whether via capillary flow and/or via other flow mechanisms, as represented via liquid flow arrows L. In at least some examples, the first porous element <NUM> may comprise and/or be modeled as a plurality of channels, such as but not limited to, the plurality of side-by-side channels <NUM> shown in <FIG>. Each channel <NUM> is defined between and by the side walls <NUM> of spaced apart, side-by-side elongate elements <NUM>.

<FIG> is a diagram <NUM> including a side view schematically representing an example electroosmotic flow of liquid through an example channel <NUM> of an example first porous element. As shown in <FIG>, walls <NUM> of elements (<NUM> in <FIG>) define a channel <NUM> through which liquid carrier <NUM> flows via electroosmotic pumping action. In general terms, electroosmotic flow arises because an electric charge arises at an interface of dissimilar materials, such as materials with a different chemical potential. This electric charge (e.g. negative charge <NUM> in <FIG>), in turn, attracts charge (e.g. positive charge <NUM>) from the bulk of the liquid (e.g. liquid carrier <NUM> within channel <NUM>), forming a double layer. When an electric field (e.g. EF as in <FIG>) is placed parallel to the pane of the interface, the mobile charge in the double layer moves as described by Coloumb's law. This moving charge drags the liquid (e.g. <NUM>) along with it, first dragging the liquid near the wall (as represented by the largest arrow W), which then entrains the rest of the fluid in the channel as represented by the array <NUM> of arrows extending across a width of channel <NUM>.

<FIG> is a diagram including a side view schematically representing an example image formation device <NUM>. In some examples, the image formation device <NUM> comprises at least some of substantially the same features and attributes as the image formation device <NUM> in <FIG>, with substrate <NUM> being implemented as a substrate <NUM> supported by a rotatable drum <NUM>. In some instances, the substrate <NUM> may be referred to as an outer portion of rotatable drum <NUM>. In a manner consistent with <FIG>, the image formation device <NUM> comprises a fluid ejection device <NUM> and first porous element <NUM> arranged in series about an external surface of substrate <NUM> which rotates (as represented by arrow R). The rotating substrate <NUM> receives, via the fluid ejection device <NUM>, deposited droplets <NUM> (of ink particles <NUM> within a liquid carrier <NUM>) to at least partially form an intended image on the substrate <NUM>. After such deposition, the first porous element <NUM> removes at least a portion of the liquid carrier from the substrate <NUM>. In some such examples, it will be understood that at this point in the process of forming an image on the substrate, the first porous element <NUM> is not acting to remove ink residue from substrate <NUM> in the same manner as is to be performed later by cleaner unit <NUM> after formation of the image on the substrate <NUM> has been fully completed, such as after media transfer station <NUM>.

In some examples, the first porous element <NUM> may comprise at least some of substantially the same features and attributes as the first porous element <NUM> (e.g. part of liquid removal arrangement <NUM>) previously described in association with <FIG> and/or those first porous elements (and associated liquid removal arrangements) later described in association with at least <FIG>.

As further shown in <FIG>, in some examples image formation device <NUM> may comprise a dryer <NUM> downstream from the first porous element <NUM> to further remove liquid (including but not limited to liquid carrier <NUM>) from the substrate <NUM>.

As further shown in <FIG>, the image formation device <NUM> may comprise a media transfer station <NUM>, which may comprise an impression roller or cylinder <NUM> which forms a nip <NUM> with drum <NUM> to cause transfer of the formed image on substrate <NUM> of drum <NUM> to print medium <NUM> moving along path W.

As further shown in <FIG>, in some examples the image formation device <NUM> may comprise a cleaner unit <NUM>, which follows the media transfer station <NUM> and which precedes the fluid ejection device <NUM>. The cleaner unit <NUM> is to remove any residual ink particles <NUM> and/or components of droplets <NUM> from the substrate <NUM> prior to operation of the fluid ejection device <NUM>.

<FIG> is a diagram including a side view schematically representing an example image formation device <NUM>. In some examples, the image formation device <NUM> comprises at least some of substantially the same features and attributes as the image formation device <NUM> in <FIG>, except with a substrate <NUM> being implemented as a belt <NUM> in a belt arrangement <NUM> (instead of a drum-type arrangement) among other differences noted below. As shown in <FIG>, the substrate-belt arrangement <NUM> includes an array <NUM> of rollers <NUM>, <NUM>, <NUM>, <NUM>, with at least one of these respective rollers comprising a drive roller and the remaining rollers supporting and guiding the substrate <NUM>. Via these rollers, the substrate <NUM> (as belt <NUM>) continuously moves in travel path T to expose the substrate <NUM> to at least the fluid ejection device <NUM> and first porous element <NUM>, in a manner consistent with the devices as previously described in association with at least <FIG>.

In some such examples, the belt <NUM> may sometimes be referred to as an endless belt because it forms a loop about a plurality of rollers in some examples, with the belt having no discrete end or beginning. In some examples, the belt <NUM> also may be referred to as rotating in an endless loop, i.e. a loop having no discrete end or beginning. It will be further understood that the scope of the terms "endless", "loop" and the like in association with the terms "belt" may be applicable with respect to other examples of the present disclosure in an appropriate context.

In a manner consistent with at least <FIG>, the image formation device <NUM> comprises a fluid ejection device <NUM> and first porous element <NUM> arranged along the travel path T through which the substrate <NUM> moves so that the substrate <NUM> may receive, via the fluid ejection device <NUM>, deposited droplets <NUM> (of ink particles <NUM> within a liquid carrier <NUM>) to at least partially form an intended image on the substrate <NUM>. After such deposition, first porous element <NUM> removes at least a portion of the liquid carrier <NUM> from the substrate <NUM>. In some examples, the first porous element <NUM> may comprise at least some of substantially the same features and attributes as the first porous element <NUM> previously described in association with <FIG> and/or those first porous elements (and associated liquid removal arrangements) later described in association with at least <FIG>.

As further shown in <FIG>, in some examples image formation device <NUM> may comprise a dryer <NUM> downstream from the first porous element <NUM> to further remove liquid (including but not limited to liquid carrier <NUM>) from the substrate <NUM>. As further shown in <FIG>, in some examples the image formation device <NUM> may comprise a media transfer station <NUM>, which may comprise an impression roller or cylinder <NUM> which forms a nip <NUM> with roller <NUM> to cause transfer of the formed image from substrate <NUM> at roller <NUM> onto print medium <NUM> moving along path W. As further shown in <FIG>, in some examples the image formation device <NUM> may comprise a cleaner unit <NUM> which follows the media transfer arrangement <NUM> and which precedes at least the fluid ejection device <NUM>. The cleaner unit <NUM> is to remove any residual ink particles <NUM> and/or components of droplets <NUM> from the substrate <NUM> prior to operation of the fluid ejection device <NUM>.

As further shown in <FIG>, in some examples the image formation device <NUM> comprises a primer unit <NUM> which precedes (i.e. is upstream from) the fluid ejection device <NUM> and which may deposit a primer layer or layer of binder material onto the substrate <NUM> and onto which the image may be formed, such as via operation of fluid ejection device <NUM>, first porous element <NUM>, dryer <NUM>, etc. In some examples, this primer layer or binder layer may be transferred with the formed image onto the print medium <NUM>.

In some examples, such a primer unit <NUM> may be implemented in the image formation device <NUM> of <FIG> with the primer unit <NUM> being located between the cleaner unit <NUM> and the fluid ejection device <NUM>.

<FIG> is a diagram including a side view schematically representing an example image formation device <NUM> including a first porous element <NUM> for removing from a substrate <NUM>. In some examples, the example image formation device <NUM> comprises at least some of substantially the same features and attributes as the image formation devices, including a first porous element <NUM> and a substrate <NUM>, as previously described in association with at least <FIG>. In some examples, the substrate <NUM> may take the form of a belt <NUM> as shown in <FIG> or may take the form of an outer portion <NUM> of a drum as shown in <FIG>. In some examples, substrate <NUM> may comprise a non-transfer media, e.g. the final print medium onto which the image is to reside.

As further shown in <FIG>, the first porous element <NUM> forms part of a liquid removal arrangement <NUM> in which the first porous element <NUM> comprises a belt <NUM> supported by, and rotating in an endless loop, about a plurality of rollers, such as rollers <NUM>, <NUM>, <NUM> with at least one of these rollers comprising a drive roller. Roller <NUM> is positioned to be in pressing contact against the substrate <NUM> at a nip <NUM> which defines a contact zone or first liquid removal zone F1, as shown via dashed lines in <FIG>. Via the first porous element <NUM>, liquid is removed from substrate <NUM> in the first liquid removal zone F1 in a manner consistent with that described in at least <FIG> to remove liquid (e.g. liquid carrier <NUM>) from the substrate <NUM>.

Because the first porous element <NUM> in the form of a belt <NUM> rotates in a loop (as represented by directional arrow E), different portions of belt <NUM> will engage the substrate <NUM> as the belt <NUM> rotates. Similarly, at the same time that the belt <NUM> is rotating (directional arrow E) in a loop, the substrate <NUM> is moving along travel path T. As shown in <FIG>, roller <NUM> rotates (arrow R) in a direction complementary with the travel path T of substrate <NUM>. In some such examples, the belt <NUM> moves (rotates in the endless loop) at a speed which is substantially the same as the speed at which substrate <NUM> travels along the travel path T. In one aspect, this arrangement may minimize or eliminate shear forces, which might otherwise be present if the belt <NUM> and substrate <NUM> were moving at substantially different speeds.

In some examples, the support <NUM> comprises an outer portion <NUM> which is hard (e.g. not compressible) and the roller <NUM> comprises a relative soft, compressible outer portion <NUM>. However, in some examples, the outer portion <NUM> of the support <NUM> comprises a relatively soft, compressible outer portion while the outer portion <NUM> of the roller <NUM> comprises a hard (e.g. not compressible) outer portion. In some examples, the substrate <NUM> may comprise a thickness on the order of <NUM> millimeter while the first porous element <NUM> (e.g. belt <NUM>) may comprise a thickness of about <NUM> micro-meters, as further illustrated in the examples of <FIG>.

In some examples, a voltage applied to create the electric field to cause electroosmotic flow (through the first porous element <NUM>) may comprise tens to hundreds of Volts, wherein the electric field may comprise about <NUM> to about <NUM> Volts per millimeter. Meanwhile, in some such examples, the outer portion <NUM> of roller <NUM> may comprise a conductivity on the order of (or greater than) <NUM><NUM> Ohms - cm, which may result in a response time of <NUM> milliseconds or less. Accordingly, in some examples, this response time of the outer portion <NUM> of roller <NUM> may be at least <NUM> times faster than the contact time of the outer portion <NUM> of roller <NUM> with the substrate in the nip <NUM>.

<FIG> is a diagram of an example image formation device <NUM> comprising at least some of substantially the same features and attributes as image formation device <NUM>, except with the liquid removal arrangement <NUM> comprising additional elements to remove liquid from first roller <NUM>. In some such examples, these additional elements may comprise a blade <NUM> to scrape liquid from the first roller <NUM> and a receptacle <NUM> to collect the liquid removed from the first roller <NUM>. By employing these elements in a location remote from (e.g. other than directly against) the substrate <NUM>, the liquid removal arrangement <NUM> may facilitate liquid removal without the encumbrances of such mechanical elements directly against the substrate <NUM>, thereby allowing faster run times and less wear and tear on the substrate <NUM>.

<FIG> is a diagram including a sectional side view schematically representing an example first porous element <NUM> of an example liquid removal arrangement <NUM> of an example image formation device. In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the same features and attributes as the liquid removal arrangements, as previously described in association with at least <FIG>. In some examples, the substrate <NUM> may take the form of a belt <NUM> as shown in <FIG>, may take the form of an outer portion <NUM> of a drum as shown in <FIG>, or make take other forms such as a final media on which the image will reside.

In particular, the liquid removal arrangement <NUM> comprises an arrangement substantially similar to that shown in <FIG>, except further depicting at least some aspects of the first porous element <NUM> (<FIG>) as first porous element <NUM> in <FIG> and further depicting support <NUM> (<FIG>) as support <NUM> in <FIG>. As shown in <FIG>, in some examples support <NUM> may comprise a conductive material and/or a conductive member, such as but not limited to, a conductive open cell foam. As noted in association with <FIG>, this support <NUM> may comprise an outer portion of a roller (e.g. roller <NUM> in <FIG>) or an outer portion of a rotatable drum, such as in later described <FIG>.

As further depicted in <FIG>, the structure and/or materials forming the first porous element <NUM> may comprise and/or be modeled as, a plurality of channels <NUM> between side-by-side elements <NUM>, like those shown in <FIG>.

In some examples, the first porous element <NUM> may comprise an insulative member with a desired conductivity provided via the support <NUM> for inducing electroosmotic flow. However, in some examples, the first porous element <NUM> may comprise an at least partially conductive member (or material). In some examples, the resistivity of the first porous element <NUM> may be on the order of (or greater than) <NUM><NUM> Ohms - cm, assuming a contact area (between the substrate <NUM> and the first porous element <NUM>) of about <NUM> to about <NUM> millimeters and a speed of <NUM> meter/second, which may achieve a response time of more than a few milliseconds. In some examples, this response time may be at least <NUM> times longer than the contact time of the first porous element <NUM> with the substrate <NUM> in a nip <NUM>. In some examples, a longer contact area may be implemented, which may not necessarily be depicted in at least some of the examples of the present disclosure.

In some examples, the substrate <NUM> may comprise a thickness (T1) on the order of <NUM> millimeter while the first porous element <NUM> may comprise a thickness (T2) on the order of <NUM> micro-meter. Meanwhile, the conductive support <NUM> may comprise a thickness (T3) which is substantially greater than the thickness (T2) of the first porous element <NUM>. <FIG> also depicts the ink particles <NUM> (at least partially forming an image) and liquid carrier <NUM> as having a thickness (T4), prior to removing the liquid, of about <NUM> micro-meter in their sandwiched position between the first porous element <NUM> and the substrate <NUM>.

<FIG> is a diagram <NUM> which provides a further illustration of a liquid removal arrangement <NUM> (including first porous element <NUM>) like liquid removal arrangement <NUM> in <FIG>, except omitting the support <NUM>. It will be understood that a support like support <NUM> or other support may provide backing to first porous element <NUM> for strength, conductivity, and/or other purposes, such as removing liquid from the first porous element <NUM> as in at least some of the later described examples, shown in <FIG>.

<FIG> is a diagram <NUM> including a sectional side view schematically representing an example first porous element <NUM> of a liquid removal arrangement <NUM> and substrate <NUM> of an example image formation device.

In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the same features and attributes as the liquid removal arrangements, as previously described in association with at least <FIG>, except with the first porous element <NUM> comprising a double layer configuration including a first layer <NUM> and a second layer <NUM>. Together, the respective layers <NUM>, <NUM> define the same type of channels <NUM> between elements <NUM>, as shown in <FIG>, and <FIG>. In some such examples, the first layer <NUM> comprises a first conductivity and the second layer <NUM> comprises a second conductivity which is greater than the first conductivity. In some examples, the second layer <NUM> may comprise a support layer, which is less flexible, has greater strength, etc. than the first layer <NUM>. Together, the two layers <NUM>, <NUM> may comprise an overall conductivity similar to that described in association with at least <FIG>.

<FIG> and <FIG> are each a diagram including a side view schematically representing a liquid removal arrangement according to the invention and including a first porous element to remove liquid from a substrate and a second porous element in contact with the first porous element to remove liquid from the first porous element.

<FIG> is a diagram <NUM> schematically representing an example liquid removal arrangement <NUM>. In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the same features and attributes as, and/or an example implementation of, the liquid removal arrangement <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>). For instance, in a manner similar to that shown in <FIG>, the liquid removal arrangement <NUM> comprises a plurality of rollers <NUM>, <NUM>, <NUM> supporting the first porous element <NUM> in the form of a belt <NUM>, with roller <NUM> comprises substantially the same features as roller <NUM> in <FIG>.

As shown in <FIG>, each of the rollers <NUM>, <NUM>, <NUM> (supporting belt <NUM>) rotate in a first direction (counterclockwise in this example as represented by arrow R), while the roller <NUM> rotates in a second direction (clockwise as represented by arrow V).

In addition, liquid removal arrangement <NUM> comprises additional elements to remove liquid from belt <NUM> (of the first porous element <NUM>) to prepare (e.g. dry) portions of the belt <NUM> prior to another pass in contact against substrate <NUM> for primary liquid removal. In particular, as show in <FIG>, in some examples, the liquid removal arrangement <NUM> comprises an additional roller <NUM> further supporting belt <NUM> and positioned between rollers <NUM>, <NUM> in a location directly opposite a rotatable drum <NUM> with belt <NUM> passing between the roller <NUM> and drum <NUM> to form nip <NUM>. An outer portion <NUM> of drum <NUM> defines a second porous element, having at least some of substantially the same features and attributes as the first porous element <NUM>, except with the second porous element being applied in the second contact zone F2 whereas the first porous element (in the form of belt <NUM>) acts to remove liquid from substrate <NUM> in first liquid removal zone F1. In some instances, the first liquid removal zone F1 also may referred to as a first contact zone F1. In some examples, the second porous element in the form of an outer portion <NUM> of drum <NUM> may have a configuration like that described for outer portion <NUM> of drum <NUM> in association with <FIG>.

Moreover, as further shown in <FIG>, the liquid removal arrangement <NUM> may comprise an electric field applicator <NUM> to apply an electric field (in a manner consistent as described in association with <FIG>) in a second liquid removal zone F2 to cause electroosmotic flow of liquid carrier <NUM> through belt <NUM> (i.e. first porous element <NUM>) and through outer portion <NUM> of drum <NUM> (i.e. the second porous element) in order to remove the liquid carrier <NUM> from the belt <NUM> (i.e. the first porous element <NUM>).

It will be further understood that the liquid captured via the outer portion <NUM> (i.e. the second porous element) of drum <NUM> is to be removed so that a given portion of the outer portion of drum <NUM> may be "dried" enough so that upon its next pass through the nip <NUM>, the given portion of the outer portion <NUM> will be ready and able to remove liquid from the belt <NUM> (i.e. first porous element) in second contact zone F2 via electroosmotic flow.

With this in mind, in some examples the liquid removal arrangement <NUM> may comprise a mechanical liquid removal element M to collect the liquid which was removed from belt <NUM> (e.g. the first porous element) via operation of electroosmotic flow in the second liquid removal zone F2 via the outer portion <NUM> (e.g. second porous element). This mechanical liquid removal element M may comprise a wide variety of elements, locations, etc., at least some of which are further described later below in association with at least <FIG>.

Together, the roller <NUM>, drum <NUM>, electric field applicator <NUM>, and mechanical liquid removal arrangement M may be viewed as, or referred to as, a second liquid removal arrangement <NUM>, which forms part of and/or is associated with the primary liquid removal arrangement <NUM>.

<FIG> is a diagram including a side view schematically representing one example belt <NUM>, which comprises one example implementation of the first porous element <NUM> in the form of the belt <NUM>. In some examples, the example belt <NUM> may comprise an example implementation of one of the belts (as a first porous element) as previously described in association with at least <FIG> for use in removing liquid in a first liquid removal zone F1.

As shown in <FIG>, in some examples, belt <NUM> may comprise multiple layers, such as but not limited to layers <NUM>, <NUM>, <NUM>. In some examples, the first layer <NUM> comprises an adhesion prevention layer <NUM>, which may comprise a hydrophobic material, and which may have a thickness (T7) on the order of <NUM> microns. In some examples, the second layer <NUM> may comprise a porous media layer for liquid adsorption, and which may have a thickness (T8) on the order of <NUM> to <NUM> microns. In some examples, the third layer <NUM> may comprise a support layer, and which may have a thickness (T9), which may in some examples be greater than the thickness T8 of second layer <NUM>. In some examples, the third layer <NUM> may comprise a flexible woven material, which may comprise a metal or a polymer with some conductivity. In some examples, the third layer <NUM> may comprise pores to permit liquid to flow through layer <NUM> after it passes through layers <NUM>, <NUM> during liquid removal from the substrate. In some such examples, the pores may have an average diameter of on the order of <NUM> microns.

In some examples, the first layer <NUM> is to engage the substrate <NUM> while the third layer <NUM> is to be in electrical communication with a power supply, e.g. electric field applicator, to apply the electric field (EF) to induce electroosmotic flow as described throughout examples of the present disclosure. The second layer <NUM> sandwiched between layers <NUM>, <NUM> acts to induce flow, such as capillary flow, aided by electroosmotic flow in the same direction indicated by arrow EF.

In some examples, a structure like that shown in <FIG> may be implemented as an outer portion of a drum (e.g. outer portion <NUM> of drum <NUM> in <FIG>) to function as a second porous element, which removes liquid from a first porous element such as belt <NUM> in <FIG> via electroosmotic flow in a second liquid removal zone F2.

<FIG> is a diagram including a side view schematically representing different mechanical elements for removing liquid from an outer portion of a drum or other structure acting as, or including, a second porous element. In some examples, the various mechanical elements shown in <FIG> comprise at least some example implementations of the mechanical liquid removal element M shown in <FIG>, and later shown in <FIG>.

As shown in <FIG>, in some examples the mechanical liquid removal element M may be implemented as example configuration <NUM> in which a blade <NUM> is positioned within an interior of drum <NUM> to scrape the liquid (which was previously removed from the first porous element <NUM> as belt <NUM>) from an inner surface of the outer portion <NUM> of drum <NUM> for collection into receptacle <NUM>. It will be further understood that, in some examples, the blade <NUM> can be omitted with the outer portion <NUM> (i.e. second porous element) of drum <NUM> being structured to enable the liquid, under electroosmotic pumping action, to flow directly into the receptacle <NUM> without the blade <NUM>.

As further shown in <FIG>, in some examples the mechanical liquid removal element M may be implemented as example configuration <NUM> in which the blade <NUM> is positioned on an exterior of drum <NUM> to scrape the liquid (which was previously removed from the first porous element <NUM> as belt <NUM>) from an exterior surface of the outer portion <NUM> of drum <NUM> for collection into receptacle <NUM>.

As further shown in <FIG>, in some examples the mechanical liquid removal element M may be implemented as example configuration <NUM> in which a squeegee roller <NUM> is positioned on an exterior of drum <NUM> to force the liquid (which was previously removed from the first porous element <NUM> as belt <NUM>) from an exterior surface of the outer portion <NUM> of drum <NUM> for collection into a receptacle (like <NUM>) or other structure. The collected liquid may be recycled, re-used, or discarded.

It will be understood that the various mechanical elements, such as blade <NUM>, squeegee roller <NUM>, receptacle <NUM>, and the like, may be applied in a variety of other locations, combinations, etc. relative to an outer portion <NUM> of a drum <NUM> in order to remove the liquid in a desired manner.

It will be further understood that, in viewing <FIG> and <FIG>, the location of the mechanical liquid removal element M is merely representative and that the mechanical liquid removal element is not strictly limited to a location within an interior of a drum (e.g. <NUM> in <FIG>, <NUM> in <FIG>) but may have other locations (e.g. exterior) in proximity to such drums in order to implement the above-describe mechanical removal of liquid from the outer portion of such drums, rollers, etc. (which are acting as a second porous element for removing liquid from a first porous element, such as <NUM>).

<FIG> is a diagram <NUM> schematically representing an example liquid removal arrangement <NUM>. In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the same features and attributes as the liquid removal arrangement <NUM> in <FIG>, except for omitting the support roller <NUM> so that drum <NUM> (an outer portion <NUM> of which acts as a second porous element) is contact with belt <NUM> (acting as first porous element <NUM>) without a support roller directly opposite from the drum <NUM> as in <FIG>.

<FIG> is a diagram <NUM> schematically representing an example liquid removal arrangement <NUM>. In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the same features and attributes as the liquid removal arrangements described in association with at least <FIG> to remove liquid from a substrate via a first porous element <NUM> (e.g. as belt <NUM>), and/or to remove liquid from a first porous element <NUM> (e.g. as belt <NUM>) via a second porous element (embodied as outer portion <NUM> of drum <NUM>). Like liquid removal arrangement <NUM>, the liquid removal arrangement <NUM> in <FIG> comprises first porous element <NUM> in the form of a belt <NUM> supported by a plurality of rollers <NUM>, <NUM>, <NUM> (like rollers <NUM>, <NUM>, <NUM>), with at least one such roller comprising a drive roller. In other respects, roller <NUM> may comprise features like roller <NUM>.

<FIG> also illustrates that in some examples, the substrate <NUM> may comprise a media, such as the final print medium, on which the formed image will reside. As such, in this example shown in <FIG>, the substrate <NUM> is not directly supported by a roller or drum at the point at which the first porous element <NUM> (supported by roller <NUM>) engages the substrate <NUM>.

As further shown in <FIG>, the liquid removal arrangement <NUM> comprises a second liquid removal arrangement <NUM> which comprises a rotatable drum <NUM> disposed on one side of belt <NUM> and a roller <NUM> located on an opposite side of belt <NUM>, with rotatable drum <NUM> within an interior <NUM> of the belt <NUM> and roller <NUM> exterior of the loop defined by belt <NUM>. Roller <NUM> directly supports belt <NUM> at this point of contact, and together the roller <NUM> and drum <NUM> form a nip <NUM> through which belt <NUM> moves. At the nip <NUM> at which second contact zone F2 is defined, liquid is removed from belt <NUM> (e.g. a first porous element) via electroosmotic flow (caused by electric field applicator <NUM>) through belt <NUM> and through an outer portion <NUM> of rotatable drum <NUM> (e.g. a second porous element), such as previously described in various examples, such as but not limited to <FIG>. The iquid removed from belt <NUM> and carried by outer portion <NUM> is engaged via the mechanical liquid removal element M in a manner consistent with that described in association with at least <FIG>.

As shown in <FIG>, each of the rollers <NUM>, <NUM>, <NUM> (supporting belt <NUM>) and the drum <NUM> rotate in a first direction (counterclockwise in this example as represented by arrow R), while the roller <NUM> rotates in a second direction (clockwise as represented by arrow V).

<FIG> is a diagram <NUM> schematically representing an example liquid removal arrangement <NUM>. In some examples, the liquid removal arrangement <NUM> comprises at least some of substantially the same features and attributes as the liquid removal arrangements described in association with at least <FIG> to remove liquid from a substrate via a first porous element, and/or to remove liquid from the first porous element via a second porous element. In some examples, the liquid removal arrangement <NUM> comprises a first porous element <NUM> in the form of an outer portion <NUM> of a rotatable drum <NUM>, which comprises one example implementation of the arrangement in <FIG> in which the first porous element <NUM> takes the form of an outer portion <NUM> of a rotatable drum <NUM>.

Accordingly, as shown in <FIG>, the drum <NUM> is in rolling contact (arrow R) against the substrate <NUM> (which moves along travel path T) at nip <NUM>, at which electroosmotic flow causes removal of liquid (e.g. liquid carrier <NUM>) from substrate <NUM> via the outer portion <NUM> (a first porous element) of drum <NUM> in contact zone F1. Such removed liquid is carried within the outer portion <NUM> of drum <NUM> as drum <NUM> rotates (arrow R) until a given portion of outer portion <NUM> (the first porous element) enters nip <NUM> as shown in <FIG>, with nip <NUM> forming part of a second liquid removal arrangement <NUM>. In some examples, this arrangement <NUM> may comprise a rotatable drum <NUM> located within an interior of drum <NUM> and a roller <NUM> in rolling contact with outer portion <NUM> of rotatable drum <NUM>. Drum <NUM> rotates in the same direction as, but relative to drum <NUM> with an exterior surface of outer portion <NUM> (a second porous element) of drum <NUM> in rolling contact against an inner wall of an outer portion <NUM> of drum <NUM>. In some instances, the drum <NUM> may be referred to as being nested within an interior of drum <NUM>.

In a manner similar to that described for <FIG>, via application of an electric field via applicator <NUM>, electroosmotic flow in the contact zone F2 causes liquid to be removed from outer portion <NUM> of drum <NUM> as liquid flows through outer portion <NUM> (a first porous element) of drum <NUM>, and through outer portion <NUM> (a second porous element) of rotatable drum <NUM>, with the removed liquid being further removed, collected, etc. via the mechanical liquid removal element M.

<FIG> is a diagram schematically representing an example image formation device <NUM>. In some examples, the image formation device <NUM> comprises an example image formation device comprising at least some of substantially the same features and attributes as, and/or an example implementation of, the liquid removal arrangement <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>).

The image formation device <NUM> comprises at least some of substantially the same features and attributes as the image formation devices described in association with at least <FIG>, <FIG>. Moreover, as shown in <FIG>, in some examples, downstream from the fluid ejection device <NUM>, the image formation device <NUM> may comprise a charge emitter <NUM> to emit charges onto deposited droplets <NUM> (of ink particles <NUM> within a liquid carrier <NUM>) to cause electrostatic migration of the ink particles <NUM> through the liquid carrier <NUM> toward the substrate <NUM> as shown in portion <NUM> of <FIG>, and to cause electrostatic fixation of the ink particles <NUM> against the substrate <NUM>, as shown in portion <NUM> of <FIG>. In some examples, the liquid carrier <NUM> may comprise a non-aqueous fluid, which in some examples may comprise a low viscosity, dielectric oil, such as an isoparaffinic fluid. Some versions of such dielectric oil may be sold under the trade name Isopar®. Among other attributes, the non-aqueous liquid carrier may be more easily removed from the substrate <NUM> (than an aqueous liquid carrier), at least to the extent that the substrate <NUM> may comprise some aqueous absorptive properties. In some examples, the non-aqueous fluid may comprise charge directors and/or dispersants to implement low field conductivity, which may facilitate removal of the liquid carrier <NUM> in its non-aqueous form from the substrate <NUM>.

As further shown in dashed box B of portion <NUM> of <FIG>, the deposited charges <NUM> become attached to the deposited ink particles <NUM>, which then migrate to substrate <NUM> due to the electrostatic forces of the charges <NUM> being attracted to the grounded substrate <NUM>. Moreover, as shown in dashed box C in portion <NUM> of <FIG>, upon all of the deposited ink particles <NUM> (with attached charges <NUM>) becoming electrostatically fixed relative to the substrate <NUM>, the liquid carrier <NUM> exhibits a supernatant relationship relative to the ink particles <NUM>, which are electrostatically fixed against the substrate <NUM>. With the liquid carrier <NUM> in this arrangement, the liquid carrier <NUM> can be readily removed from the substrate <NUM> without disturbing (or without substantially disturbing) the electrostatically fixed ink particles <NUM> in their desired, targeted position on the substrate <NUM> by which an image is at least partially formed. With this in mind, the liquid removal arrangement <NUM> acts to remove the liquid carrier <NUM> from the substrate <NUM> in a manner consistent with the previously described examples of a liquid removal arrangement, such as but not limited to liquid removal arrangement <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>).

With further reference to <FIG>, the charge emitter <NUM> may comprise a corona, plasma element, or other charge generating element to generate a flow of charges. The charge emitter <NUM> may sometimes be referred to as a charge source, charge generation device, and the like. The generated charges may be negative or positive as desired. In some examples, the charge emitter <NUM> comprises 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 emitter <NUM>).

In the particular instance shown in <FIG>, the emitted charges <NUM> can become attached to the ink particles <NUM> 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 <NUM> will have a negative charge or alternatively all or substantially all of the charged ink particles <NUM> will have a positive charge.

<FIG> is a diagram including a side view schematically representing an example image formation device <NUM>, which comprises at least one example implementation of the image formation device <NUM> of <FIG>. In some examples, the image formation device <NUM> comprises at least some of substantially the same features and attributes as image formation device <NUM> in <FIG>, while further comprising a charge emitter <NUM> located along the travel path T of substrate <NUM> (on rotatable drum <NUM>) between the fluid ejection device <NUM> and the first porous element <NUM>. In a manner similar to that represented in <FIG>, the charge emitter <NUM> emits charges (e.g. <NUM> in <FIG>) to cause electrostatic migration of the ink particles <NUM> through the liquid carrier <NUM>, and electrostatic fixation of, ink particles <NUM> relative to substrate <NUM> in manner described in association with <FIG>. As in the example of <FIG>, the liquid carrier <NUM> may be a non-aqueous fluid.

<FIG> is a block diagram schematically representing an example image formation engine <NUM>. In some examples, the image formation engine <NUM> may form part of a control portion <NUM>, as later described in association with at least <FIG>, such as but not limited to comprising at least part of the instructions <NUM>. In some examples, the image formation engine <NUM> may be used to implement at least some of the various example devices and/or example methods of the present disclosure as previously described in association with <FIG> and/or as later described in association with <FIG>. In some examples, the image formation engine <NUM> (<FIG>) and/or control portion <NUM> (<FIG>) may form part of, and/or be in communication with, an image formation device.

In general terms, the image formation engine <NUM> is to control at least some aspects of operation of the image formation devices and/or methods as described in association with at least <FIG> and <FIG>.

As shown in <FIG>, the image formation engine <NUM> may comprise a fluid ejection engine <NUM>, a charge emitter engine <NUM>, and/or a liquid removal engine <NUM>.

In some examples, the fluid ejection engine <NUM> controls operation of the fluid ejection device <NUM> (e.g. at least <FIG>) to deposit droplets of ink particles <NUM> within a liquid carrier <NUM> onto a substrate <NUM> (e.g. at least <FIG>) as described throughout the examples of the present disclosure.

In some examples, the charge emitter engine <NUM> is to control operation of a charge emitter (e.g. <NUM> in <FIG>, <FIG>) to emit airborne electrical charges to induce electrostatic migration of ink particles <NUM> toward the substrate <NUM> and electrostatic fixation of the migrated ink particles <NUM> at their target locations in a pattern at least partially forming an image, such as described in association with <FIG> and/or various examples throughout the present disclosure.

In some examples, in general terms the liquid removal engine <NUM> controls operation of at least a liquid removal arrangement to remove the liquid carrier (e.g. <NUM> in <FIG>) from a substrate (e.g. <NUM> in <FIG>) and/or from a first porous element via a second porous element. Such control may comprise control of operation of at least the various elements, portions, aspects of the liquid removal throughout the examples of the present disclosure, such as but not limited to the examples of <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), <NUM> (<FIG>), and/or <NUM> (<FIG>).

In some examples, the liquid removal engine <NUM> comprises a position parameter <NUM> to control a position of a first porous element (as a drum or belt), such as via controlling a position of a roller(s) and/or drum via which the first porous element is implemented. Similarly, in some examples the position parameter <NUM> is to control a position of a second porous element (as a belt or drum) such as via controlling a position of a roller(s) and/or drum via which the second porous element is implemented.

In some examples, the liquid removal engine <NUM> may comprise a speed parameter <NUM> by which a speed of the belt or rotatable drum is controlled (and/or tracked) via operation of the support and/or drive rollers of one of the various example belt arrangements described in association with at least <FIG>.

In some examples, the liquid removal engine <NUM> may comprise an electric field parameter <NUM> to control (and/or track) the electric field applied to cause electroosmotic flow to remove liquid from a substrate via a first porous element (e.g. as belt <NUM> in <FIG> at first liquid removal zone F1, in one example) and/or to remove liquid from the first porous element (e.g. belt <NUM>) via a second porous element, such as outer portion <NUM> of drum <NUM> in <FIG> at second liquid removal zone F2 , in one example.

It will be understood that, in at least some examples, the image formation engine <NUM> is not strictly limited to the particular grouping of parameters, engines, functions, etc. as represented in <FIG>, such that the various parameters, engines, functions, etc. may operate according to different groupings than shown in <FIG>.

<FIG> is a block diagram schematically representing an example control portion <NUM>. In some examples, control portion <NUM> provides one example implementation of a control portion forming a part of, implementing, and/or generally managing the example image formation devices, as well as the particular portions, fluid ejection devices, charge emitters, porous elements, electric field applicators, liquid removal elements, elements, devices, user interface, instructions, engines, parameters, functions, and/or methods, as described throughout examples of the present disclosure in association with <FIG> and <FIG>.

In some examples, control portion <NUM> includes a controller <NUM> and a memory <NUM>. In general terms, controller <NUM> of control portion <NUM> comprises at least one processor <NUM> and associated memories. The controller <NUM> is electrically couplable to, and in communication with, memory <NUM> to generate control signals to direct operation of at least some the image formation devices, various portions and elements of the image formation devices, such as fluid ejection devices, charge emitters, porous elements, electric field applicators, liquid removal 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 <NUM> stored in memory <NUM> to at least direct and manage depositing droplets of ink particles and liquid carrier to form an image on a media, jetting droplets, directing charges onto ink particles, removing liquids (e.g. via porous elements, electric field applicators, etc.), etc. as described throughout the examples of the present disclosure in association with <FIG> and <FIG>. In some instances, the controller <NUM> or control portion <NUM> 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 <NUM> are implemented as a, or may be referred to as, a print engine, an image formation engine, and the like, such as but not limited to the image formation engine <NUM> in <FIG>.

In response to or based upon commands received via a user interface (e.g. user interface <NUM> in <FIG>) and/or via machine readable instructions, controller <NUM> generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller <NUM> is embodied in a general purpose computing device while in some examples, controller <NUM> 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 emitters, porous elements, electric field applicators, liquid removal 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 <NUM>, the term "processor" shall mean a presently developed or future developed processor (or processing resources) that executes machine readable instructions contained in a memory or that includes circuitry to perform computations. In some examples, execution of the machine readable instructions, such as those provided via memory <NUM> of control portion <NUM> cause the processor to perform the above-identified actions, such as operating controller <NUM> 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 <NUM>. The machine readable instructions may include a sequence of instructions, a processor-executable machine learning model, or the like. In some examples, memory <NUM> comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller <NUM>. In some examples, the computer readable tangible medium may sometimes be referred to as, and/or comprise at least a portion of, a computer program product. 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 <NUM> may be embodied as part of at least one application-specific integrated circuit (ASIC), at least one field-programmable gate array (FPGA), and/or the like. In at least some examples, the controller <NUM> 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 <NUM>.

In some examples, control portion <NUM> may be entirely implemented within or by a stand-alone device.

In some examples, the control portion <NUM> 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 <NUM> may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion <NUM> 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 <NUM> includes, and/or is in communication with, a user interface <NUM> as shown in <FIG>. In some examples, user interface <NUM> 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 thereof, elements, user interfaces, instructions, engines, functions, and/or methods, etc. as described in association with <FIG> and <FIG>. In some examples, at least some portions or aspects of the user interface <NUM> are provided via a graphical user interface (GUI), and may comprise a display <NUM> and input <NUM>.

<FIG> is a flow diagram schematically representing an example method. In some examples, method <NUM> may be performed via at least some of the same or substantially the same image formation devices, portions, fluid ejection devices, charge emitters, porous elements, electric field applicators, liquid removal elements, elements, control portion, user interface, etc. as previously described in association with <FIG>. In some examples, method <NUM> may be performed via at least some of the same or substantially the same image formation devices, portions, fluid ejection devices, charge emitters, porous elements, electric field applicators, liquid removal elements, control portion, user interface, etc. other than those previously described in association with <FIG>.

As shown at <NUM> in <FIG>, in some examples method <NUM> may comprise moving a substrate along a travel path. As shown at <NUM> in <FIG>, method <NUM> may comprise depositing, via a fluid ejection device, droplets of ink particles within a liquid carrier onto the substrate to at least partially form an image on the substrate.

As shown at <NUM> in <FIG>, method <NUM> may comprise engaging the substrate with a first porous element, while applying an electric field across the substrate and the belt, to cause electroosmotic flow removal of at least a portion of the liquid carrier from the substrate.

Claim 1:
An image formation device (<NUM>) comprising:
a support (<NUM>) to support movement of a substrate (<NUM>) along a travel path;
a fluid ejection device (<NUM>) along the travel path to deposit droplets (<NUM>) of ink particles within a liquid carrier onto the substrate to at least partially form an image on the substrate;
a first porous element (<NUM>, <NUM>) located downstream along the travel path from the fluid ejection device to be in contact against the substrate to remove, via electroosmotic flow through the first porous element, at least a portion of the liquid carrier from the substrate; and characterized in that the image formation device further comprises
a second porous element (<NUM>) in contact against the first porous element at a location separated from a location at which the first porous element engages the substrate to remove, via electroosmotic flow through the second porous element, liquid carrier from the first porous element.