WO2021118546A1

WO2021118546A1 - Image formation with ink removal

Info

Publication number: WO2021118546A1
Application number: PCT/US2019/065601
Authority: WO
Inventors: Omer Gila; Napoleon J. Leoni
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2019-12-11
Filing date: 2019-12-11
Publication date: 2021-06-17
Anticipated expiration: 2022-06-11

Abstract

A device includes a first substrate to move along a travel path, a fluid ejection device and a transfer station. The fluid ejection device is to deposit droplets of ink particles within a liquid carrier in a first pattern on the first substrate. At the transfer station, the first pattern of ink particles is transferred from the first substrate, via a transfer element, to a second substrate to remove residual ink from the first substrate after a prior instance of image formation on the first substrate. In some examples, the second substrate includes an image formation medium. In some examples, the second substrate includes an ink-attracting portion interposed, along the travel path, between the transfer station and the fluid ejection device, wherein the ink-attracting portion is selectively engageable against the first substrate.

Description

IMAGE FORMATION WITH INK REMOVAL

Background

[0001] Modern printing techniques involve a wide variety of media, whether rigid or flexible, and for a wide range of purposes. Some printing techniques may involve attempting to remove residual ink from various surfaces used during printing.

Brief Description of the Drawings

[0002] FIG. 1 is a diagram including side views schematically representing an example image formation device including a fluid ejection device and ink removal arrangement, and/or an example method of ink removal.

[0003] FIG. 2A is a diagram including a side view schematically representing an example image formation device including a fluid ejection device.

[0004] FIG. 2B is a diagram including a side view schematically representing an example ink removal arrangement.

[0005] FIG. 3 is a diagram including a side view schematically representing an example image formation device including a rotatable drum-type substrate and an image formation medium acting as an ink removal element.

[0006] FIGS. 4-6 are each a diagram including a side view schematically representing an example image formation device including a rotatable drum- type substrate and a belt-type ink removal arrangement.

[0007] FIG. 7 is a diagram including a side view schematically representing an example image formation device including a belt-type substrate and a belt-type ink removal arrangement.

[0008] FIG. 8 is a diagram including side views schematically representing at least some aspects of an example image formation device, including a charge emitter for electrostatic fixation of ink particles, a liquid removal element, and an ink removal arrangement. [0009] FIG. 9 is a diagram including a side view schematically representing an example image formation device including a rotatable drum-type substrate with a charge emitter, liquid removal element, and ink removal arrangement.

[0010] FIG. 10A is an example image formation engine.

[0011] FIG. 10B is a block diagram schematically representing an example control portion.

[0012] FIG. 10C is a block diagram schematically representing an example user interface.

[0013] FIG. 11 is a flow diagram schematically representing an example method of image formation.

Detailed Description

[0014] 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.

[0015] At least some examples of the present disclosure are directed to removing residual ink from a substrate, such as an intermediate transfer member, used repeatedly in image formation. Such removal may enhance quality of the image formation, enhance transferring the image, enhance color consistency, and/or enhance a lifespan of the substrate.

[0016] In some examples, an image formation device comprises a first substrate to move along a travel path, a fluid ejection device to deposit droplets of ink particles within a liquid carrier in a first pattern on the first substrate, and a transfer station at which the first pattern of ink particles is transferred from the first substrate, via a transfer element, to a second substrate to remove residual ink from the first substrate after a prior instance of image formation on the first substrate. In some such examples, the second substrate comprises an image formation medium and the transfer element comprises an impression drum. In some instances of deposition of the droplets, the first pattern of the deposition of droplets comprises a non-image uniform layer. In at least this context, the term “non-image” refers to a uniform layer which does not form any recognizable image, but instead exhibits a generally uniform appearance.

[0017] However, in some such examples, the second substrate comprises an ink-attracting portion interposed, along the travel path, between the transfer station and the fluid ejection device, wherein the ink-attracting portion is selectively engageable against the first substrate. In some such examples, the ink-attracting portion may have an affinity (e.g. attraction) for the residual ink, which is greater than an affinity of the first substrate for residual ink. In some such examples, the ink-attracting portion may have an affinity (e.g. attraction) for the residual ink, which is greater than an affinity of an image formation medium for the residual ink. Among other ink-attracting attributes, the ink- attracting portion may be generally tacky or adhesive in nature, and/or specifically made to attract residual ink from substrate. In some examples, the ink-attracting portion may comprise an ink mixture, including ink particles and other components, such as binders, adhesives, and the like.

[0018] These examples, and additional examples, are described later in association with at least FIGS. 1-11.

[0019] FIG. 1 is a diagram including side views schematically representing an example image formation device including a fluid ejection device 110 and/or ink removal arrangement 150. In some examples, the image formation depicted in FIG. 1 and the later FIGS. 2A-9 also may be understood as example methods of image formation and/or ink removal.

[0020] As shown in FIG. 1 , a substrate 105 moves along a travel path T. In some examples, the substrate 105 may be supported via a support, which 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 FIGS. 3-6 and FIG. 7, respectively. In some examples, the substrate 105 may sometimes be referred to as a blanket or intermediate transfer member.

[0021] As further shown in FIG. 1 , in some examples the image formation device 100 comprises a fluid ejection device 110 and an ink removal arrangement 150. The fluid ejection device 110 is located along the travel path T to deposit droplets 111 of ink particles 134 within a liquid carrier 132 onto the substrate 105, as represented within dashed box A. In some examples, the liquid carrier 132 may comprise an aqueous liquid carrier while in some examples, the liquid carrier 132 may comprise a non-aqueous liquid carrier, such as later described in association with at least FIGS. 8-9.

[0022] In some examples, such as in the normal course of printing, the deposited ink particles 134 may form an image on substrate 105, which may be later transferred to an image formation medium.

[0023] Flowever, it will be understood that in some examples, such as when it is desired to remove residual ink from substrate 105, the fluid ejection device 110 is used to deposit ink particles 134 as a full coverage layer of ink particles. This full coverage ink particle layer may be used in removing residual ink on substrate 105 remaining from prior iterations of image formation using substrate 105. FIG. 2A provides one example of the presence of residual ink 129 on the substrate 105 prior to the deposition of droplets 111 of ink particles 134 (within liquid carrier 132) used to remove the residual ink 129.

[0024] In some examples, the above-described full coverage layer of ink particles may comprise a 100 percent coverage ink particle layer on substrate 105. In some examples of the various example implementations throughout the present disclosure, the layer of ink particles deposited on substrate 105 and used to remove residual ink may comprise a substantially full coverage layer comprising at least 99.9 percent coverage, at least 99.5 percent coverage, at least 99 percent coverage, at least 98 percent coverage, at least 97 percent coverage, at least 96 percent coverage, or at least 95 percent coverage.

[0025] Moreover, in some examples throughout the present disclosure, the full coverage layer (or substantially full coverage layer) may sometimes be referred to as, or correspond to, a non-image uniform layer. In this regard, the full coverage layer (or substantially full coverage layer) exhibits a generally uniform appearance which does not depict an image, and therefore may be referred to as a non-image layer in some examples. Conversely, the non-image, uniform layer may sometimes be referred to as a full coverage layer (of ink particles) or substantially full coverage layer.

[0026] For the time being, this discussion will address the latter operation of the fluid ejection device 110 to deposit a full coverage ink particle layer on substrate 105. Upon such full coverage deposition, the substrate 105 will be completely covered with ink particles 134 as shown at 152 in FIG. 1 prior to the substrate 105 engaging ink removal arrangement 150, which is downstream from the fluid ejection device 110 in order to remove the residual ink from substrate 105.

[0027] In some examples, the ink removal arrangement 150 comprises at least one roller 153 which places a second substrate 157 into rolling contact against the substrate 105 (i.e. first substrate) at nip 151 to cause the full coverage ink particle layer 152 to be transferred onto the second substrate 157, as represented by arrow 155. After such transfer, the substrate 105 may be free of residual ink 129 as represented by arrow 159, and at least partially prepared to later receive further image formation thereon.

[0028] In some examples, the substrate 105 may sometimes be referred to as a first substrate or an intermediate transfer member because the substrate 105 may initially receive ink particles, which are then transferred later to the second substrate 157. Accordingly, in some examples the substrate 105 (e.g. first substrate) acts as an intermediate location to receive and retain the ink particles until their later transfer to the second substrate 157.

[0029] FIG. 2B is a diagram including a side view schematically representing an example ink removal arrangement 200. In some examples, the ink removal arrangement 200 may comprise at least some of substantially the same features and attributes as ink removal arrangement 150 of FIG. 1 and/or comprise one example implementation of an the ink removal arrangement 150 in FIG. 1.

[0030] In the example of FIG. 2B, the ink removal arrangement 200 comprises the second substrate 257 (like second substrate 157) including an outer surface carrying, and/or defined by, an ink-attracting substance 147A. Upon advancement of second substrate 257 about rotatable roller 203, the ink- attracting substance 147A engages the first substrate 105 at nip 166 at which the residual ink 129 becomes adhered to, and subsumed within, the ink- attracting substance 147A on substrate 257 such that as substrate 257 exits nip 166, both the ink-attracting substance 147A and the residual ink 129 remain in contact against second substrate 257 (as represented by arrow 147B) to thereby remove residual ink 129 from substrate 105. Via this ink removal, the surface of substrate 105 becomes free of residual ink 129, as represented via arrow 159.

[0031] The ink-attracting substance 147A comprises an affinity for residual ink 129 on substrate 105. Among other ink-attracting attributes, the ink-attracting substance 147A may be generally tacky or adhesive in nature, and/or specifically made to attract residual ink 129 from substrate 105. Accordingly, the second substrate 257 may sometimes be referred to as carrying, or comprising, an ink-attracting portion implemented via the ink-attracting substance 147A. The ink- attracting substance 147A may comprise a regular ink, a special purpose ink, and/or a non-ink substance.

[0032] A determination as to the frequency of removing residual ink from substrate 105 may depend on several factors, such as but not limited to, a time period, a number of impressions on substrate 105, and/or the printing performance of the image formation device.

[0033] As later described in association with at least FIG. 3, in some examples the second substrate 257 in FIG. 2B may comprise an image formation medium, while in some examples, the second substrate 257 in FIG. 2B may comprise a belt of an ink removal arrangement as later described in association with at least FIGS. 4-9.

[0034] In some examples, the ink removal arrangement 200 may sometimes be referred to as a transfer station.

[0035] FIG. 3 is a diagram including a side view schematically representing an example image formation device 300. In some examples, the image formation device 300 comprises at least some of substantially the same features and attributes as the image formation devices, previously described in association with FIGS. 1 -2B, and further comprising the first substrate (e.g. 105 in FIGS. 1- 2B) being implemented in the form of an outer surface 309 of a rotatable drum

308 and with an image formation medium 357 acting as an ink removal element. In some examples, the image formation medium 357 may sometimes referred to as a second substrate. In some examples, the outer surface 309 comprises an elastomeric material (e.g. rubber, silicone, etc.) to enable the outer surface 309 to conform to a surface topography of the image formation medium 357, which may enhance transferring an image or ink layer from the outer surface 309 to the image formation medium 357. In some examples, the outer surface 309 may comprise a coating to enhance release of the image or ink layer from the outer surface 309 to the image formation medium 357.

[0036] As shown in FIG. 3, in order to remove residual ink from the substrate

309 remaining from prior iterations of image formation on substrate 309, in some examples the fluid ejection device 110 deposits droplets 111 of ink particles (e.g. 134) within a liquid carrier 132 to create a full coverage ink particle layer 336 on the substrate 309, as represented at A. In a manner similar to that described in association with FIGS. 1-2B, this full coverage layer 336 of ink particles covers and induces the residual ink (e.g. 129 in FIGS. 2A- 2B) to adhere to the ink particles in the full coverage layer 336. The ink particles 134 deposited by the fluid ejection device 110 may comprise the normal ink used for image formation on substrate 309 or may comprise a special-purpose ink with tackiness and/or other properties particularly suited to causing adherence of residual ink (on substrate 309) to the special-purpose ink. [0037] In some examples, after such deposition, a dryer 370 downstream from fluid ejection device 110 may evaporate any remaining liquid (e.g. liquid carrier 132) and/or solidify the ink particles on the substrate 309.

[0038] Upon further rotation of drum 308, the substrate 309 engages image formation medium 357 at nip 359, via support of rotatable impression drum 380, such that upon advancement of the image formation medium 357 (as represented via arrow G), the full coverage ink particle layer 336 becomes transferred onto image formation medium 357 as represented at B. In this way, the residual ink which previously remained on the substrate 309 is removed from the substrate 309 as the residual ink is transferred along with, and/or as part of, the full coverage ink particle layer 336. Following this residual ink removal procedure, the image formation medium 357 (or pertinent portion thereof) continues advancing away from the nip 359 (as represented by arrow H), after which the image formation medium 357 may be discarded, recycled, etc.

[0039] As further shown in FIG. 3, the impression drum 380 may be selectively moved inward and outward, as represented via arrow F, to selectively engage the substrate 309 on drum 308.

[0040] In some instances, the arrangement of the impression drum 308 and image formation medium 357 relative to drum 308 may sometimes be referred to as a transfer station 381 and/or as an ink removal arrangement 381.

[0041] As further shown in FIG. 3, in some examples the image formation device 300 may comprise a cleaner unit 393 which is downstream from the ink removal arrangement 381 and which precedes at least the fluid ejection device 110. The cleaner unit 343 is to further condition the substrate 309 after operation of the ink removal arrangement 381 and prior to operation of the fluid ejection device 110.

[0042] As further shown in FIG. 3, in some examples the image formation device 300 comprises a primer unit 390 which precedes (i.e. is upstream from) the fluid ejection device 110 and which may deposit a primer layer or layer of binder material onto the substrate 309 and onto which the full coverage ink particle layer 336 or an image may be formed, such as via operation of fluid ejection device 110, dryer 370, etc. In some examples, this primer layer or binder layer may be transferred with the full coverage ink particle layer 336 or formed image onto the image formation medium 357.

[0043] FIG. 4 is a diagram including a side view schematically representing an example image formation device 400. In some examples, the image formation device 400 comprises at least some of substantially the same features and attributes as image formation device 300 (FIG. 3), while further comprising an ink removal arrangement 340 in addition to a transfer station 381. In this example, the transfer station 381 is not employed for removing residual ink from substrate 309. Instead, the ink removal arrangement 340 acts to remove residual ink from substrate 309.

In some examples, the ink removal arrangement 340 comprises a belt 344, which is supported and/or driven via rollers 341 , 342, 343 such that belt 344 may move along a path toward drum 308, as represented via arrow Q, and then belt 344 may move along a path away from drum 308, as represented by arrow V. In some examples, the roller 342 and/or the entire arrangement 340 is selectively movable toward and away from substrate 309, as represented via arrow K, such that the belt 344 is selectively engageable against substrate 309. In some examples, a control portion (e.g. control portion 1500 in FIG. 10B) may be used to control a timing of selectively engaging the ink-attracting portion relative to the first substrate to implement the selective engagement, as described in various examples, whether the engagement may occur during non printing cycles, printing cycles, or both.

[0044] The belt 344 may comprise an ink- attracting surface (e.g. 147A), in a manner similar to that described in association with FIG. 2B, and accordingly, may sometimes be referred to as an ink-attracting portion. In some examples, the rollers 341 , 342, 343 and belt 344 may be referred to as a roll-to-roll arrangement and may be at least partially enclosed within a housing, which may form a cassette, with at least roller 342 exposed for causing a portion of belt 344 to be in rolling contact against the substrate 309. In some such examples, the ink-attracting portion is not regularly refreshed via a liquid ink supply.

[0045] As shown in FIG. 4, in order to remove residual ink from substrate 309 of drum 308, at least the impression drum 380 of the transfer station 381 is selectively dis-engaged and moved away from the substrate 309, while the ink removal arrangement 340 is selectively moved toward drum 308 such that belt 344 engages substrate 309 of drum 308.

[0046] In a manner similar to that described in association with FIG. 3, fluid ejection device 110 deposits a full coverage ink particle layer 336 onto substrate 309 (at A) to cover, and cause adherence of, residual ink on substrate 309 to the ink particle layer 336. Upon further rotation of drum 308, the full coverage ink particle layer 336 on substrate 309 bypasses the dis-engaged transfer station 381 , and engages the belt 344 at roller 342 (via nip 346) such that the full coverage ink particle layer 336 becomes transferred off substrate 309 and onto the belt 344. After such transfer, the substrate 309 becomes free of residual ink (e.g. 129 in FIGS. 1-2B) while the ink removal arrangement 340 retains the residual ink as part of the full coverage ink particle layer 336. In some examples, the belt 344 is taken up by roller 343 and the belt 344 (and/or the whole ink removal arrangement 340) may be discarded or recycled at a later time.

[0047] FIG. 5 is a diagram including a side view schematically representing an example image formation device 500. In some examples, the image formation device 500 comprises at least some of substantially the same features and attributes as image formation device 400 (FIG. 4). Flowever, in this example, the residual ink on substrate 309 is removed via engagement of the belt 344 against the substrate 309 without the fluid ejection device 110 printing a full coverage ink particle layer 336 onto substrate 309 (to assist in removing the residual ink 129). In this example, the ink- attracting portion (e.g. surface) of the belt 344 may provide sufficient affinity for the residual ink on substrate 309 to ensure removal of the residual ink from the substrate 309 when belt 344 contacts the substrate 309.

[0048] Accordingly, via this arrangement, the ink removal arrangement 340 is continually removing residual ink from the substrate 309, but without the fluid ejection device 110 periodically applying a full coverage ink particle layer (e.g. 336 in FIG. 4). Rather, in this example implementation, the image formation device relies on the ink-attracting properties of the belt 344 to achieve removal of the residual ink 129 from the substrate 309. It will be further understood that the ink removal arrangement 340 may be periodically engaged, instead of being continuously engaged, against the substrate 309.

[0049] In some examples, the belt 344 is initially provided in a state in which the belt 344 already embodies (e.g. exhibits) its ink-attracting properties. Flowever, in some examples, the ink- attracting properties of the belt 344 may be initially established and/or refreshed via the fluid ejection device 110 depositing a full coverage ink particle layer 336 on substrate 309 and the belt 344 engaging the full coverage ink particle layer 336 so that the belt 344 takes up the ink of the full coverage ink particle layer 336. In some such examples, maneuvering the belt 344 along (e.g. back and forth) rollers 341 , 342, 343 within a housing may distribute the ink particles of the layer 336 along the belt 344 for later use as an adhering component to attract residual ink 129 from substrate 309.

[0050] As in the example image formation device 400 of FIG. 4, in the example image formation device 500, the transfer station 381 is dis-engaged from substrate 309 during the operation of the ink removal arrangement 340, such that normal printing operations may be temporarily suspended during operation of the ink removal arrangement 340.

[0051] It will be understood that in some examples, a full coverage ink particle layer (e.g. 336 in FIG. 4) may periodically be applied onto substrate 309 and used to facilitate removing residual ink 129 onto belt 344, in a manner similar to that described in association with FIG. 3.

[0052] FIG. 6 is a diagram including a side view schematically representing an example image formation device 600. In some examples, the image formation device 600 comprises at least some of substantially the same features and attributes as image formation device 500 (FIG. 5). Flowever, in this example, the ink removal arrangement 340 may remain engaged against the substrate 309 even while normal printing cycles are performed in which the impression drum 380 (of transfer station 381) remains engaged against substrate 309 to transfer images from substrate 309 to image formation medium 357.

[0053] After such transfer of the image to the image formation medium 357, any residual ink is removed via engagement of belt 344 (of ink removal arrangement 340) against substrate 309.

[0054] Accordingly, like the example in FIG. 5, the ink removal arrangement 340 in image formation device 600 is continually removing residual ink from the substrate 309, but without the fluid ejection device 110 periodically applying a full coverage ink particle layer (e.g. 336 in FIG. 4). Rather, in this example implementation, the image formation device relies on the ink-attracting properties of the belt 344 to achieve removal of the residual ink 129 from the substrate 309. It will be further understood that the ink removal arrangement 340 may be periodically engaged, instead of being continuously engaged, against the substrate 309.

[0055] FIG. 7 is a diagram including a side view schematically representing an example image formation device 700. In some examples, the image formation device 700 comprises at least some of substantially the same features and attributes as the image formation device in FIG. 1-6, except with the first substrate (e.g. 105, 309) being implemented as a belt 706 in a belt arrangement 707 (instead of a drum-type arrangement) among other differences noted below. As shown in FIG. 7, the substrate-belt arrangement 707 includes an array 711 of rollers 712, 713, 714, 716, 718, with at least one of these respective rollers comprising a drive roller and the remaining rollers supporting and guiding the belt 706. Via these rollers, the belt 706 moves along the travel path T to expose the belt 706 to at least the fluid ejection device 110 and ink removal arrangement 340, in a manner consistent with the devices as previously described in association with at least FIGS. 1-6.

[0056] In some such examples, the belt 706 may sometimes be referred to as an endless belt 706 because it forms a loop about a plurality of rollers in some examples, with the belt 706 having no discrete end or beginning. In some examples, the belt 706 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.

[0057] In a manner consistent with at least FIGS. 1-6, the image formation device 700 comprises a fluid ejection device 110 arranged along the travel path T through which the belt 706 moves so that the belt 706 may receive, via the fluid ejection device 110, deposited droplets 111 (of ink particles 134 within a liquid carrier 132) to form an intended pattern on the belt 706. In some examples, the intended pattern may comprise an image for later transfer to an image formation device while in some examples the intended pattern may comprise a full coverage ink particle layer for removing residual ink. [0058] As further shown in FIG. 7, in some examples the image formation device 700 may comprise a media transfer station 760, which may comprise an impression roller or cylinder 767 which forms a nip 761 with roller 718 to cause transfer of the intended pattern from belt 706 at roller 718 onto image formation medium 767 moving along path W. In some examples, the transfer station 760 may comprise at least some of substantially the same features and attributes as one of the transfer stations 381 of FIGS. 3-6.

[0059] As further shown in FIG. 7, in some examples the image formation device 700 may comprise a cleaner unit 393 like cleaner unit 393 in FIG. 3, and may comprise a primer unit 390 like primer unit 390 in FIG. 3.

[0060] FIG. 8 is a diagram schematically representing an example image formation device 1000. In some examples, the image formation device 1000 comprises an example image formation device comprising at least some of substantially the same features and attributes as the previously described examples in association with FIGS. 1-7. Moreover, in some examples, downstream from the fluid ejection device 110, the image formation device 1000 may comprise a charge emitter 1040 to emit charges onto deposited droplets 111 (of ink particles 134 within a liquid carrier 132) to cause electrostatic migration of the ink particles 134 through the liquid carrier 132 toward the substrate 105 as shown in portion 1022 of FIG. 8, and to cause electrostatic fixation of the ink particles 134 against the substrate 105, as shown in portion 1024 of FIG. 8. In some examples, the liquid carrier 132 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 105, at least to the extent that the substrate 105 may comprise some aqueous absorptive properties.

[0061] As further shown in dashed box B at portion 1022 in FIG. 8, the deposited charges 1043 become attached to the deposited ink particles 134, which then migrate to substrate 105 due to the electrostatic forces of the charges 1043 being attracted to the grounded substrate 105. Moreover, as shown in dashed box C at 1024 in FIG. 8, upon all of the deposited ink particles 134 (with attached charges 1043) becoming electrostatically fixed relative to the substrate 105, the liquid carrier 132 exhibits a supernatant relationship relative to the ink particles 134, which are electrostatically fixed against the substrate 105. With the liquid carrier 132 in this arrangement, the liquid carrier 132 can be readily removed from the substrate 105 without disturbing (or without substantially disturbing) the electrostatically fixed ink particles 134 in their desired, targeted position on the substrate 105 by which an intended pattern is formed. In some examples, the intended pattern may comprise an image while in some examples the intended pattern may comprise a full coverage ink particle layer used for removing residual ink, such that no image is formed.

[0062] With further reference to FIG. 8, the charge emitter 1040 may comprise a corona, plasma element, or other charge generating element to generate a flow of charges. The charge emitter 1040 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 1040 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 1040).

[0063] In the particular instance shown in FIG. 8, the emitted charges 1043 can become attached to the ink particles 134 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 134 will have a negative charge or alternatively all or substantially all of the charged ink particles 134 will have a positive charge.

[0064] As further shown at 1026 in FIG. 8, in some examples the image formation device 1000 comprises a liquid removal element 1044 downstream along travel path T from the charge emitter 1040. The liquid removal element 1044 may take any one of several forms, such as but not limited to, a squeegee roller, air knife, belt, doctor blade, etc. The liquid removal element 1044 acts to remove the excess liquid carrier 132 (in its supernatant relationship relative to ink particles 134) shown in box C at 1024 in FIG. 8, such that the just the ink particles 134 remain on substrate 105 as shown at 1026 in FIG. 8.

[0065] While not shown in FIG. 8, the image formation device 1000 may comprise a dryer 370 downstream from the liquid removal element 1044 to further dry or solidify the ink particles 134 on the substrate 105. Examples of such a dryer 370 are shown in FIGS. 3-7. The dryer may comprise heated air, infrared radiation, ultraviolet radiation, and the like.

[0066] As further shown at 1028 in FIG. 8, in some examples an image 1025 on substrate 105 (following the liquid removal at 1026) is transferred at a transfer station 1060, which may comprise at least some of substantially the same features and attributes as one of the transfer stations (e.g. 381 in FIGS. 3-6; and 760 in FIG. 7). Accordingly, as shown in FIG. 8, an image 1025 formed of ink particles 134 on substrate 105 is advanced along travel path T toward nip 1061, at which rolling contact is made with image formation medium 357 as supported via rotating impression drum 380 to transfer the image 1025 onto the image formation medium 357. Flowever, after such transfer, some residual ink particles 129 may remain on the substrate 105, as shown at 1028 in FIG. 8. [0067] As further shown at 1037 in FIG. 8, an ink removal arrangement 1065 may be located along the travel path T of substrate 105 downstream from the image transfer station 1060, in a manner similar to that shown in FIGS. 3-6 or FIG. 7. In some examples, the ink removal arrangement 1065 may comprise at least some of substantially the same features and attributes as the ink removal arrangements 340 as previously described in association with at least FIGS. 1- 7. As shown in FIG. 8, the ink removal arrangement 1065 comprises at least one rotatable roller 342 supporting a belt 344 for selective engagement, at nip 1066, against the substrate 105. The belt 344 includes an outer surface carrying an ink- attracting substance 347A, which has an affinity for residual ink 129 on substrate 105. Among other ink-attracting attributes, the ink-attracting substance 347A may be generally tacky or adhesive in nature, and/or specifically made to attract residual ink 129 from substrate 105. Accordingly, the belt 344 may sometimes be referred to as, or comprising, an ink-attracting portion. As previously noted, the ink-attracting substance 347A may comprise a regular ink, a special purpose ink, and/or a non-ink substance.

[0068] As belt 344 travels into rolling contact against substrate 105, the ink- attracting substance 347A of belt 344 engages the residual ink 129 at nip 1066 and picks up the residual ink 129, which becomes adhered to and with the ink- attracting substance 347A on belt 344, as represented by composite substance 347B. Stated differently, the composite substance 347B comprises both the ink- attracting substance 347A and the residual ink 129, which was removed from substrate 105. As further shown in FIG. 8, after nip 1066, the substrate 105 is free of residual ink, as represented via reference numeral 1038. As shown previously in at least FIGS. 3-7, the residual-ink-free substrate 105 continues on travel path T toward fluid ejection device 110, with it being understood that additional cleaner units (e.g. 393), primer units (e.g. 390) and the like may be interposed between the ink removal arrangement 1065 and the fluid ejection device 110.

[0069] With further reference to FIG. 8, it will be further understood that the ink removal arrangement 1065 may be omitted in some examples of image formation device 1000. In some such examples, the residual ink 129 may be removed from substrate 105 via transfer station 1060 in FIG. 9 in a manner similar to that described in at least FIG. 3 in which a special printing cycle (using fluid ejection device 110) is implemented and the residual ink 129, along with the deposited full coverage ink layer, is transferred onto an image formation medium like image formation medium 357 in FIG. 8.

[0070] It will be further understood that the image formation medium 357 may comprise a continuous web of material in some examples, as shown in FIG. 8, or may comprise separate sheets of material in some examples.

[0071] FIG. 9 is a diagram including a side view schematically representing an example image formation device 1100, which comprises at least one example implementation of the image formation device 1000 of FIG. 8. Accordingly, in some examples, the image formation device 1100 comprises at least some of substantially the same features and attributes as earlier described example image formation devices (e.g. 300, 400, 500, 600), while further comprising a charge emitter 1040 and a liquid removal element 1044 located along the travel path T of substrate 309 (on rotatable drum 308) between the fluid ejection device 110 and dryer 370. In a manner similar to that represented in FIG. 8, the charge emitter 1040 emits charges (e.g. 1043 in FIG. 8) to cause electrostatic migration of the ink particles 134 through the liquid carrier 132 , and electrostatic fixation of, ink particles 134 relative to substrate 309 in manner similar to that described in association with FIG. 8. As in the example of FIG. 8, the liquid carrier 132 may be a non-aqueous fluid.

[0072] Moreover, in a manner similar to that represented in FIG. 8, the liquid removal element 1044 is to remove the liquid carrier 132 from the substrate 309 while leaving the ink particles 134 in their intended pattern on the substrate. [0073] As previously noted in at least some of the previously described examples (e.g. FIGS. 1-8), in some examples the pattern of ink particles formed on substrate 309 via image formation device 1100 may comprise an intended image for transfer to an image formation medium, such as during routine printing, while in some examples, the pattern of ink particles formed on substrate 309 comprises a full (e.g. 100 percent) coverage of ink particles 134 implemented during an ink removal cycle used to remove residual ink from the substrate 309.

[0074] FIG. 10A is a block diagram schematically representing an example image formation engine 1250. In some examples, the image formation engine 1250 may form part of a control portion 1500, as later described in association with at least FIG. 10B, such as but not limited to comprising at least part of the instructions 1511. In some examples, the image formation engine 1250 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 FIGS. 1-9 and/or as later described in association with FIGS. 10B-11. In some examples, the image formation engine 1250 (FIG. 10A) and/or control portion 1500 (FIG. 10B) may form part of, and/or be in communication with, an image formation device. [0075] In general terms, the image formation engine 1250 is to control at least some aspects of operation of the image formation devices and/or methods as described in association with at least FIGS. 1 -9 and 10B-11.

[0076] As shown in FIG. 12A, the image formation engine 1250 may comprise a fluid ejection engine 1252, a charge emitter engine 1257, a liquid removal engine 1258, and/or an ink removal engine 1280.

[0077] In some examples, the fluid ejection engine 1252 controls operation of the fluid ejection device 110 (e.g. at least FIG. 1) to deposit droplets of ink particles 134 within a liquid carrier 132 onto a substrate 105 (e.g. at least FIG. 1) as described throughout the examples of the present disclosure. In some examples, the fluid ejection device 110 may operate in an image formation mode (per parameter 1253) to form an image on a substrate, such as an image formation medium. In some examples, the fluid ejection device 110 may operate in an ink removal mode (per parameter 1257) in which the fluid ejection device 110 is to deposit droplets which will result in a 100 percent ink coverage uniform layer on to a first substrate (e.g. intermediate transfer member) as part of removing residual ink on the first substrate remaining from prior iterations of image formation via the first substrate. In some examples, an image formation device may operate in both an image formation mode and an ink removal mode, as described in some of the previous examples in association with FIGS. 1-9. [0078] In some examples, the charge emitter engine 1257 is to control operation of a charge emitter (e.g. 1040 in FIGS. 8, 9) to emit airborne electrical charges to induce electrostatic migration of ink particles 134 toward the substrate 105 and electrostatic fixation of the migrated ink particles 134 at their target locations in an intended pattern, such as described in association with FIGS. 8-9 and/or various examples throughout the present disclosure.

[0079] In some examples, in general terms the liquid removal engine 1258 controls operation of at least a liquid removal arrangement to remove the liquid carrier 132 from the substrate 105, thereby leaving ink particles 134 in their electrostatically fixed position (in an intended pattern) relative to the substrate 105. [0080] In some examples, the image formation engine 1250 may comprise an ink removal engine 1280, which in general terms, is to control various elements to remove residual ink from a substrate, such as an intermediate transfer member of an image formation device. In some examples, the ink removal engine 1280 comprises an image formation medium parameter 1281 by which residual ink is to be removed via transferring the residual ink, as part of a non image full coverage ink layer, from a first substrate (e.g. intermediate transfer member) to an image formation medium. After such transfer, the ink-laden image formation medium may be discarded, recycled, etc.

[0081] In some examples, the ink removal engine 1280 may comprise an ink- attracting parameter 1282 to control selective engagement of an ink-attracting portion against the first substrate (e.g. intermediate transfer member) to cause adhesion of any ink (including residual ink) on the first substrate to the ink- attracting portion to thereby remove all the ink from the first substrate. As previously noted, the ink-attracting portion may be implemented a belt (e.g. supported by roller), a drum, or other forms.

[0082] It will be understood that, in at least some examples, the image formation engine 1250 is not strictly limited to the particular grouping of parameters, engines, functions, etc. as represented in FIG. 10A, such that the various parameters, engines, functions, etc. may operate according to different groupings than shown in FIG. 10A.

[0083] FIG. 10B is a block diagram schematically representing an example control portion 1500. In some examples, control portion 1500 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, liquid removal elements, ink removal elements, user interface, instructions, engines, parameters, functions, and/or methods, as described throughout examples of the present disclosure in association with FIGS. 1-10A and 100-11. In some examples, control portion 1500 includes a controller 1502 and a memory 1510. In general terms, controller 1502 of control portion 1500 comprises at least one processor 1504 and associated memories. The controller 1502 is electrically couplable to, and in communication with, memory 1510 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, liquid removal elements, ink removal elements, user interfaces, instructions, engines, parameters, 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 1511 stored in memory 1510 to at least direct and manage depositing droplets of ink particles (within a liquid carrier), directing charges onto ink particles, removing liquids, removing ink, etc. as described throughout the examples of the present disclosure in association with FIGS. 1 -10A and 10C-11. In some instances, the controller 1502 or control portion 1400 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 1511 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 1250 in FIG. 10A.

[0084] In response to or based upon commands received via a user interface (e.g. user interface 1520 in FIG. 10C) and/or via machine readable instructions, controller 1502 generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller 1502 is embodied in a general purpose computing device while in some examples, controller 1502 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, liquid removal elements, ink removal elements, user interfaces, instructions, engines, functions, and/or methods, etc. as described throughout examples of the present disclosure.

[0085] For purposes of this application, in reference to the controller 1502, 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 1510 of control portion 1400 cause the processor to perform the above-identified actions, such as operating controller 1502 to implement the formation of an image, ink removal, etc. 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 1510. The machine readable instructions may include a sequence of instructions, a processor-executable machine learning model, or the like. In some examples, memory 1510 comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller 1502. 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 1502 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 1502 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 1502.

[0086] In some examples, control portion 1500 may be entirely implemented within or by a stand-alone device.

[0087] In some examples, the control portion 1500 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 1500 may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion 1500 may be distributed or apportioned among multiple devices or resources such as among a server, an image formation device, and/or a user interface. [0088] In some examples, control portion 1500 includes, and/or is in communication with, a user interface 1520 as shown in FIG. 10C. In some examples, user interface 1520 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 FIGS. 1 -10B and 11. In some examples, at least some portions or aspects of the user interface 1520 are provided via a graphical user interface (GUI), and may comprise a display 1524 and input 1522.

[0089] FIG. 11 is a flow diagram schematically representing an example method 1600. In some examples, method 1600 may be performed via at least some of the same or substantially the same image formation devices, portions, fluid ejection devices, charge emitters, liquid removal elements, ink removal elements, control portion, user interface, etc. as previously described in association with FIGS. 1-10C. In some examples, method 1600 may be performed via at least some of the same or substantially the same image formation devices, portions, fluid ejection devices, charge emitters, liquid removal elements, ink removal elements, control portion, user interface, etc. other than those previously described in association with FIGS. 1-10C.

[0090] As shown at 1602 in FIG. 11 , in some examples method 1600 may comprise moving a first substrate along a travel path. As shown at 1604 in FIG. 11 , method 1600 may comprise depositing, via a fluid ejection device, droplets of ink particles within a liquid carrier to form a first non-image, uniform ink particle layer on the first substrate.

[0091] As shown at 1606 in FIG. 11 , method 1600 may comprise transferring the first non-image, uniform ink particle layer onto a second substrate.

[0092] In some examples, method 1600 may further comprise arranging the second substrate as an image formation medium, and performing the transferring of the first non-image, uniform ink particle layer via an impression drum in rolling contact with the substrate. [0093] In some examples, the method 1600 may further comprise arranging the second substrate as a second belt including an ink- attracting surface in selective engagement against the first substrate to implement the transfer, wherein the second belt is separate from, and independent of, an image formation medium.

[0094] In some examples, the method 1600 may further comprise prior to the deposition of the first non-image uniform ink particle layer onto the first substrate, depositing a second instance of droplets of ink particles within a liquid carrier to form a second non-image uniform ink particle layer onto the first substrate. In some such examples, method 1600 may further comprise transferring the second non-image, uniform ink particle layer from the first substrate onto the second substrate to cause an outer portion of the second substrate to define an ink-attracting portion to implement the transfer of the first non-image, uniform ink particle layer from the first substrate to the second substrate.

[0095] In some examples, method 1600 may further comprise arranging the first substrate to at least partially define an intermediate transfer member, and the first substrate to comprise an outer surface of at least one of a rotatable drum and a first belt.

[0096] In some examples, method 1600 may further comprise emitting airborne charges onto the deposited droplets to induce electrostatic migration of the ink particles within the liquid carrier toward, and electrostatic fixation of, the ink particles as the uniform ink particle layer relative to the substrate. In some such examples, the method 1600 may further comprise, prior to the transferring, removing at least the liquid carrier from the substrate while leaving the electrostatically fixed ink particles in the uniform ink particle layer on the substrate.

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.

Claims

1. An image formation device comprising: a first substrate to move along a travel path; a fluid ejection device to deposit droplets of ink particles within a liquid carrier in a first pattern on the first substrate; a transfer station at which the first pattern of ink particles is transferred from the first substrate, via a transfer element, to a second substrate to remove residual ink from the first substrate after a prior instance of image formation on the first substrate, wherein the second substrate comprises at least one of: an image formation medium; and an ink-attracting portion interposed, along the travel path, between the transfer station and the fluid ejection device, wherein the ink- attracting portion is selectively engageable against the first substrate.

2. The image formation device of claim 1 , wherein the ink- attracting portion comprises a belt, and further comprising: at least one roller supporting the belt in rolling contact the first substrate when the ink- attracting portion selective engages the first substrate to remove ink from the first substrate upon one of the respective instances in which the first pattern comprises a non-image uniform layer.

3. The image formation device of claim 2, wherein the fluid ejection device is to, prior to the deposition of the first pattern onto the first substrate, deposit a second instance of droplets of ink particles within a liquid carrier to form a second pattern onto the first substrate, with the second pattern comprising a second non-image uniform ink particle layer; and wherein the transfer station is to transfer the second non-image, uniform ink particle layer from the first substrate onto the second substrate to cause an outer portion of the second substrate to define an ink- attracting portion to implement the transfer of the first non-image, uniform ink particle layer from the first substrate to the second substrate.

4. The image formation device of claim 2, wherein the belt comprises an outer surface with an affinity for the non-image uniform layer of ink particles.

5. The image formation device of claim 1, wherein the liquid carrier comprises a non-aqueous fluid, and the device comprises: a charge emitter downstream from the fluid ejection device to emit airborne charges to induce electrostatic migration toward, and electrostatic fixation of, the ink particles relative to the first substrate; and a liquid removal element downstream from the charge emitter to at least partially remove the liquid carrier from the first substrate while leaving the electrostatically fixed ink particles on the first substrate.

6. The image formation device of claim 1 , wherein in a first pass of the first substrate along the travel path prior to the fluid ejection device depositing the droplets to form the first pattern on the first substrate, the fluid ejection device is to deposit the droplets of ink particles within the liquid carrier onto the first substrate in a second pattern to form an image on the first substrate, and the transfer station is to implement the transfer of the second pattern as the formed image onto the image formation medium.

7. The image formation device of claim 1 , wherein the first substrate at least partially defines an intermediate transfer member, and the first substrate comprises an outer surface of at least one of a rotatable drum and a belt.

8. An image formation device comprising: a first substrate to move along a travel path; a fluid ejection device to deposit droplets of ink particles within a non- aqueous liquid carrier to form an image on the first substrate; a charge emitter downstream from the fluid ejection device to emit airborne charges to induce electrostatic migration toward, and electrostatic fixation of, the ink particles relative to the first substrate as the formed image; a liquid removal element downstream from the charge emitter to at least partially remove the non-aqueous liquid carrier from the substrate while leaving the electrostatically fixed ink particles on the substrate; an impression drum in rolling contact with the first substrate to receive transfer of the formed image from the first substrate to an image formation medium; and an ink removal element interposed, along the travel path, between the impression drum and the fluid ejection device, and comprising an ink- attracting portion selectively engageable against the first substrate to remove residual ink remaining on the first substrate after the transfer of the formed image.

9. The image formation device of claim 8, wherein the ink removal element comprises a second substrate arranged as a belt, with an outer surface of the belt including the ink- attracting portion, and comprising a plurality of rollers supporting the belt including a first roller positioned to urge the belt into the rolling contact during engagement against the first substrate.

10. The image formation device of claim 9, comprising: a control portion to control a timing of selectively engaging the ink- attracting portion relative to the first substrate to implement the selective engagement during at least one of: printing cycles; and non-printing cycles.

11. A method comprising: moving a first substrate along a travel path; depositing, via fluid ejection device, a first instance of droplets of ink particles within a liquid carrier to form a first non-image uniform ink particle layer onto the first substrate; and transferring the first non-image, uniform ink particle layer onto a second substrate.

12. The method of claim 11 , comprising: arranging the second substrate as an image formation medium; and performing the transferring of the first non-image, uniform ink particle layer via an impression drum in rolling contact with the substrate.

13. The method of claim 11 , comprising: arranging the second substrate as a second belt including an ink- attracting surface in selective engagement against the first substrate to implement the transfer, wherein the second belt is separate from, and independent of, an image formation medium.

14. The method of claim 11 , comprising: arranging the first substrate to at least partially define an intermediate transfer member, and the first substrate to comprise an outer surface of at least one of a rotatable drum and a first belt.

15. The method of claim 13, comprising: emitting airborne charges onto the deposited droplets to induce electrostatic migration of the ink particles within the liquid carrier toward, and electrostatic fixation of, the ink particles as the uniform ink particle layer relative to the substrate; and prior to the transferring, removing at least the liquid carrier from the substrate while leaving the electrostatically fixed ink particles in the uniform ink particle layer on the substrate.