WO2021118571A1

WO2021118571A1 - Image formation including heating an image formation medium

Info

Publication number: WO2021118571A1
Application number: PCT/US2019/065959
Authority: WO
Inventors: Omer Gila; Napoleon J. Leoni
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2021-06-17

Abstract

An image formation device includes a substrate to move along a travel path, a fluid ejection device, and an impression drum. The fluid ejection device is to deposit droplets of ink particles within a liquid carrier to form an image on the substrate. The impression drum is in rolling contact with the substrate to receive transfer of the formed image from the substrate onto an image formation medium. A first heater is positioned to heat the image formation medium prior to the transfer at the impression drum.

Description

IMAGE FORMATION INCLUDING HEATING AN IMAGE FORMATION MEDIUM

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 involve the use of heat.

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 temperature control arrangement.

[0003] FIG. 2 is a diagram schematically representing various example heating elements for a temperature control arrangement.

[0004] FIG. 3 is a diagram including a side view schematically representing an example image formation device including a rotatable drum-type substrate and temperature control arrangement.

[0005] FIG. 4 is a diagram including a side view schematically representing an example image formation device including a belt-type substrate and temperature control arrangement.

[0006] FIG. 5 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 a temperature control arrangement.

[0007] FIG. 6 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 temperature control arrangement. [0008] FIG. 7A is an example image formation engine.

[0009] FIG. 7B is a block diagram schematically representing an example control portion. [0010] FIG. 7C is a block diagram schematically representing an example user interface.

[0011] FIG. 8 is a flow diagram schematically representing an example method of image formation.

Detailed Description

[0012] 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.

[0013] At least some examples of the present disclosure are directed to pre heating an image formation medium prior to transferring an image from a substrate, such as an intermediate transfer member, to the image formation medium. Via such pre-heating, an efficiency and/or effectiveness of transfer of the image may be enhanced, as well as enhancing durability and adhesion of the image on the image formation medium. In a related manner, such pre heating may enhance stabilizing a temperature of the substrate, the nip, the impression drum, etc., which may further enhance the image transfer.

[0014] In some examples, an image formation device includes a substrate to move along a travel path, a fluid ejection device, an impression drum, and a first heater. The fluid ejection device is to deposit droplets of ink particles within a liquid carrier to form an image on the substrate. The impression drum is in rolling contact with the substrate to receive transfer of the formed image from the substrate onto an image formation medium. The first heater is positioned to heat the image formation medium prior to the transfer at the impression drum. [0015] In some examples, the image formation medium may comprise paper or other cellulose-based medium.

[0016] In some examples, the image formation device comprises a first infrared sensor to sense a first temperature of the image formation medium prior to entry into the nip. In some examples, the image formation device comprises a second heater in thermal communication with the impression drum to heat the impression drum and the image formation medium. In some examples, the image formation device comprises a second infrared sensor positioned external the impression drum to sense a second temperature of at least a surface of the impression drum.

[0017] These examples, and additional examples, are described later in association with at least FIGS. 1-8.

[0018] FIG. 1 is a diagram including side views schematically representing at least some aspects of example image formation, which form at least a portion of an example image formation device 100. In some examples, the image formation depicted in FIG. 1 and the later FIGS. 2-8 also may be understood as example methods of image formation.

[0019] 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 (e.g. FIGS. 3, 6) or a plurality of rollers (FIG. 4), as later described. In some examples, the substrate 105 may sometimes be referred to as a blanket or intermediate transfer member.

[0020] As further shown in FIG. 1 , in some examples the image formation device 100 comprises a fluid ejection device 110 and a temperature control arrangement 141 associated with at least a transfer station 181. 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. 5-6. [0021] 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, such as via transfer station 181. [0022] In some examples, the transfer station 181 comprises at least an impression drum 153 which places an image formation medium 157 into rolling contact against the substrate 105 (i.e. first substrate) at nip 151 to cause the image 152 to be transferred onto the image formation medium 157, as represented by arrow 155.

[0023] As further shown at 140 in FIG. 1, in some examples the temperature control arrangement 141 of the image formation device 100 may be located adjacent a portion of the image formation medium 157 which precedes the transfer station 181. In some examples, the temperature control arrangement 141 comprises a heating element 142 positioned to direct heat onto the image formation medium 157 prior to passage of the image formation medium 157 through transfer station 181 such that the image formation medium 157 will be heated, i.e. have a temperature greater than room temperature. In some examples, the temperature of the heated image formation medium 157 may match or substantially match a temperature of the substrate 105, which may be heated to temperature greater than room temperature.

[0024] Such heating may enhance an efficiency and/or effectiveness of transferring an image 152 from substrate 105 to the image formation medium 157, among other features. For instance, such heating may improve adhesion and/or durability of the image on the image formation medium 157. Such heating may increase a temperature at nip 151. Such heating also may stabilize a temperature of the image formation medium 157, which may also stabilize a temperature of the substrate 105. In some examples, at least some of these factors work in a complimentary manner to increase a quality of image transfer and/or image formation.

[0025] As later described in association with at least FIGS. 3-8, in some examples, various sensing elements may be employed to monitor and/or help control the heating and therefore control the temperature of the image formation medium 157. Furthermore, such heating and/or sensing may be applied to the impression roller 153 of transfer station 181 , as also further described later. [0026] While the heating of the image formation medium 157 and/or impression drum (e.g. 153) can take many forms, it will be understood that such heat transfer may sometimes be referred to generally as thermal communication without necessarily specifying a particular type or manner of heat transfer.

[0027] With these arrangements in mind, it will be understood that a heated image formation medium makes contact with the image on the substrate (e.g. blanket or intermediate transfer member) in the nip (between the substrate and the impression drum) for just a few milliseconds. During this time, the image will be adhered (to the image formation medium) with sufficient strength to effectuate the transfer of the image. As part of this transfer process, in some examples polymers (of the ink) which form the image generally work to bind the image to the image formation medium. In some instances, such polymers may be referred to as binders, resins, and the like. Given this framework, a temperature of the image formation medium will impact the flow of the image (including its polymers) as well as a flow of any remaining liquid in the image (after a dryer such as dryer 370 in FIG. 3) into the fibers of the image formation medium, such as paper. Accordingly, by controlling a temperature of the image formation medium via examples of the present disclosure, the transfer of the image (from the substrate to the image formation medium) will be enhanced while also stabilizing a temperature of the substrate (e.g. blanket or intermediate transfer member), which further generally enhances image formation and transfer. For similar reasons, controlling a temperature of the impression drum may enhance stabilizing a temperature at the nip and/or a temperature of the substrate.

[0028] FIG. 2 is a diagram including a side view schematically representing various example heating elements which may form part of an example temperature control arrangement 200, such as but not limited to being one example implementation of the heating element 142 in temperature control arrangement 141 in FIG. 1 and/or one of the example heating elements of the temperature control arrangements (e.g. 341 , 541 , 141, 841) described later in association with at least FIGS. 3-6, respectively.

[0029] As shown in FIG. 2, one example heating element comprises a radiative heating element 252, which radiates energy, such as infrared waves to heat either an image formation medium (e.g. 157 in FIG. 1) and/or an impression drum (e.g. 153 in FIG. 1). For instance, the heating element 252 may comprise an infrared lamp. In some instances, such heating may referred to as contactless heating.

[0030] As further shown in FIG. 2, one example heating element 254 comprises a pair of rollers 256A, 256B through which an image formation medium 257 may be passed, such as prior to a transfer station (e.g. 181 in Fig. 1). One or both of the rollers 256A, 256B may comprise a heating unit H, which may comprise a radiative element 252, heated air element 259A, or other form of generating heat. In some examples, one of the rollers 256A, 256B is omitted while the other respective roller includes the heating unit H. In some instances, such heating via rollers 256A and/or 256B may sometimes be referred to as contact heating. It will be understood that other forms of contact heating may be used such as a heating element which slidably engages the image formation medium 257.

[0031] As further shown in FIG. 2, one example heating element may comprise a heated air element 259A, which generates heat and blows the heated air 259B toward and onto the image formation medium.

[0032] 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. 1-2, and further comprising the substrate (e.g. 105 in FIG. 1) being implemented in the form of an outer surface 309 of a rotatable drum 308 and a temperature control arrangement 341 associated with at least a transfer station 381.

[0033] As in the example of FIG. 1 , the fluid ejection device 110 of image formation device 300 in FIG. 3 may deposit droplets 111 of ink particles 134 within a liquid carrier 132 to form an image 336 (e.g. like image 152 in FIG. 1) on substrate 309. 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 image 336 on the substrate 309.

[0034] Upon further rotation of drum 308, the substrate 309 engages image formation medium 357 at nip 359, via support of rotatable impression drum 380 of transfer station 381 , such that upon advancement of the image formation medium 357 (as represented via arrow G), the formed image 336 (on substrate 309 at A) becomes transferred onto image formation medium 357 as represented at B.

[0035] As further shown in FIG. 3, the image formation device 300 comprises a temperature control arrangement 341 , which is associated with transfer station 381 , and which comprises at least some of substantially the same features and attributes as the temperature control arrangement 141 described in association with FIGS. 1-2. According, as shown in FIG. 3, in some examples, the temperature control arrangement 341 comprises a heating element H1 positioned adjacent the image formation medium 357 on its travel path G toward transfer station 381 to heat the image formation medium 357. In addition, in some examples, the temperature control arrangement 341 comprises a sensing element S1 following the heating element H1 to sense the temperature (e.g. a first temperature) of the image formation medium 357 after heating via element H 1. The sensing element S1 can take a variety of forms, and in one example implementation comprises an infrared sensing element. By sensing the temperature of the image formation medium 357, the sensing element S1 can provide feedback, such as via a control portion (e.g. 1100 in FIG. 10B), regarding operation of the heating element H1 to achieve a desired level of heating of the image formation medium 357. Via the heating element H 1 and the sensing element S1 , the temperature of the image formation medium may be raised to a selectable temperature and/or a temperature which compliments or matches a temperature of the substrate 309 of drum 308 for at least the previously described reasons. [0036] As further shown in FIG. 3, in some examples, in addition to heating element H1 and sensing element S1 , the temperature control arrangement 341 may comprise a second heating element H2 and/or second sensing element S2. The heating element H2 may be positioned internally within impression drum 380 in some examples, and near impression drum 380 in some examples. In some examples, the sensing element S1 is positioned adjacent the impression drum 380, while in some examples the sensing element S1 is positioned internally within the impression drum 380. In some examples, the heating element H2 may comprise a radiative element (e.g. 252 in FIG. 2), such as but not limited to an infrared lamp. By heating the impression drum 380 via the second heating element H2, the elevated temperature of the image formation medium 357 (due to heating via element H 1 ) may be maintained in a more uniform manner and/or maintained more effectively at the nip 359 to enhance the image transfer, image durability, etc. In a manner similar to that previously described for the first sensing element S1 , the sensing element S2 may be used to determine the temperature (e.g. a second temperature) of the impression drum 380 from heating (via heating element H2), with such determination providing feedback to control operation of heating element H2 to achieve the desired temperature of the impression drum 380 and of the image formation medium 357.

[0037] In some such examples, heating the impression drum 380 may be particularly enhance temperature control of the image formation medium 357 when the image formation medium 357 comprises a relatively thin sheet of material or when the image formation medium 357 is to make several passes around the impression drum 380, such that the image formation medium 357 might otherwise lose its heat (from heating element H1 ) over time unless heating via the impression drum 380 were to occur.

[0038] In some examples, the heating element H2 of the impression drum 380 may comprise an internally-located infrared (IR) lamp, an internally-located polyimide flexible heating element, or internally-located circulating water. In some such examples, the internally-located polyimide flexible heating element may be obtained from Minco of Minneapolis, Minnesota. In some examples, the heating element H2 may be an external heating element, i.e. one that is located external to the impression drum 380.

[0039] It will be further understood that in the example of FIG. 3 and/or other examples of the present disclosure, the first heating element H1 and/or first sensing element S1 may be omitted and the temperature control arrangement (e.g. 341 of image formation device 300) may comprise just the second heating element H2 and/or second sensing element S2.

[0040] In some examples, as shown in FIG. 3, the image formation device 300 may further comprise a heating element H3 and/or sensing element S3 to enhance control of the temperature of the drum 308 and substrate 309, which may enhance control of the temperature of the image formation medium 380. The heating element H3 may heat the drum 308 and/or substrate 309 [0041] In some examples, the image formation device 300 coordinates control of the various heating elements H1, H2, and/or H3, and of the various sensing elements S1 , S2, and/or S3, in order to achieve the desired temperature of the image formation medium 357 prior to nip 359, at nip 359, and/or after nip 359. In some such examples, the coordinated control may be implemented via at least a control portion (e.g. 1100 in FIG. 7B) and/or image formation engine (e.g. 950 in FIG. 7A). In some instances, such coordinated control may sometimes be referred to as closed loop control of the temperature of the image formation medium 357 and/or impression drum 380.

[0042] It will be further understood that in some examples, the image formation medium 357 and/or impression drum 280 may be heated in an open loop manner in which feedback (of sensed temperatures) is not used to control the heating elements in order to control a temperature of the image formation medium 357 and/or impression drum 380.

[0043] 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 transfer station 381 and which precedes at least the fluid ejection device 110.

[0044] 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 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 formed image onto the image formation medium 357.

[0045] In some examples, the outer surface 309 of drum 308 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 from the outer surface 309 to the image formation medium 357. In some examples, the outer surface 309 of drum 308 may comprise a coating to enhance release of a formed image from the outer surface 309 to the image formation medium 357.

[0046] In some examples, the image formation device 300 implements image formation on the image formation medium 357 without using a fuser downstream from the impression drum 380 of the transfer station 381.

[0047] In some examples, the image formation device 300 implements image formation on the image formation medium 357 without using a liquid release layer on the substrate 309 (e.g. substrate 105 in FIG. 1).

[0048] In some examples, the image formation device 300 implements image formation on the image formation medium 357 without using a liquid release applicator interposed between the fluid ejection device 110 and the impression drum 380 of transfer station 381.

[0049] FIG. 4 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 the image formation device in FIGS. 1-3, except with the substrate (e.g. 105, 309) being implemented as a belt 506 in a belt arrangement 507 (instead of a drum-type arrangement) among other differences noted below. [0050] As shown in FIG. 4, the substrate-belt arrangement 507 includes an array 511 of rollers 512, 513, 514, 516, 518, with at least one of these respective rollers comprising a drive roller and the remaining rollers supporting and guiding the belt 506. Via these rollers, the belt 506 moves along the travel path T to expose the belt 506 to at least the fluid ejection device 110, transfer station 181 , and/or a temperature control arrangement 541 and at least some of the various heating and/or sensing elements, in a manner consistent with the devices as previously described in association with at least FIGS. 1-3.

[0051] In some such examples, the belt 506 may sometimes be referred to as an endless belt 506 because it forms a loop about a plurality of rollers in some examples, with the belt 506 having no discrete end or beginning. In some examples, the belt 506 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.

[0052] In a manner consistent with at least FIGS. 1-3, the image formation device 500 comprises a fluid ejection device 110 arranged along the travel path T through which the belt 506 moves so that the belt 506 may receive, via the fluid ejection device 110, deposited droplets 111 (of ink particles 134 within a liquid carrier 132) to form a desired image on the belt 506.

[0053] As further shown in FIG. 4, in some examples the image formation device 500 may comprise a media transfer station 581 , which may comprise an impression roller or drum 580 which forms a nip 561 with roller 518 to cause transfer of the formed image from belt 506 (e.g. like substrate 105, 309) at impression drum 518 onto image formation medium 567 moving along path W. In some examples, the transfer station 581 may comprise at least some of substantially the same features and attributes as one of the transfer station 381 of FIG. 3.

[0054] In some examples, the image formation device 500 comprises a temperature control arrangement 541 , which comprises at least some of substantially the same features and attributes as temperature control arrangement 341 of FIG. 3. Accordingly, in some examples, the temperature control arrangement 541 comprises a first heating element H1 and/or first sensing element S1 adjacent image formation medium 557 along travel path G to heat and control the temperature (e.g. a first temperature) of the image formation medium 557 prior to entering nip 561. [0055] Moreover, in some examples, the temperature control arrangement 541 comprises a second heating element H2 and/or second sensing element S2, which may be positioned in and/or adjacent impression drum 580 to heat and control the temperature of the impression drum 580, which in turn facilitates control of the heating and temperature (e.g. a second temperature) of the image formation medium 557 at nip 561 and/or after passage through nip 561.

[0056] In some examples, the temperature control arrangement 541 may comprise a heating element H3 and/or sensing element S3 having at least some of substantially the same features and attributes as for the temperature control arrangement 341 in the image formation device 300 in FIG. 3.

[0057] In some examples, via a control portion (e.g. 1100 in FIG. 7B) and/or an image formation engine (e.g. 950 in FIG. 7A), the temperature control arrangement 541 of image formation device 500 in FIG. 4 may comprise coordinated control of the various heating elements H1 , H2, and/or H3, and of the various sensing element S1 , S2, and/or S3, to achieve the desired temperature of the image formation medium 557, impression drum 580, and of the belt 506 in a manner similar to that described for at least the image formation device 300 of FIG. 3.

[0058] As further shown in FIG. 4, in some examples the image formation device 500 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.

[0059] FIG. 5 is a diagram schematically representing an example image formation device 700. In some examples, the image formation device 700 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. 1-4. Moreover, in some examples, downstream from the fluid ejection device 110, the image formation device 700 may comprise a charge emitter 740 to emit charges 743 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 722 of FIG. 5, and to cause electrostatic fixation of the ink particles 134 against the substrate 105, as shown in portion 724 of FIG. 5. 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 in some examples.

[0060] As further shown in dashed box B at portion 722 in FIG. 5, the deposited charges 743 become attached to the deposited ink particles 134, which then migrate to substrate 105 due to the electrostatic forces of the charges 743 being attracted to the grounded substrate 105. Moreover, as shown in dashed box C at 724 in FIG. 5, upon all of the deposited ink particles 134 (with attached charges 743) 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 a desired image is formed.

[0061] With further reference to FIG. 5, the charge emitter 740 may comprise a corona, plasma element, or other charge generating element to generate a flow of charges. The charge emitter 740 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 740 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 740). In some examples, the charges may comprise free electrons.

[0062] In the particular instance shown in FIG. 5, the emitted charges 743 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.

[0063] As further shown at 726 in FIG. 5, in some examples the image formation device 700 comprises a liquid removal element 744 downstream along travel path T from the charge emitter 740. The liquid removal element 744 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 744 acts to remove the excess liquid carrier 132 (in its supernatant relationship relative to ink particles 134) shown in box C at 724 in FIG. 5, such that the just the ink particles 134 remain on substrate 105 as shown at 726 in FIG. 5.

[0064] While not shown in FIG. 5, the image formation device 700 may comprise a dryer 370 downstream from the liquid removal element 744 to further dry or solidify the ink particles 134 on the substrate 105. Examples of such a dryer 370 are shown in FIGS. 3-4. The dryer may comprise heated air, infrared radiation, ultraviolet radiation, and the like.

[0065] As further shown at 728 in FIG. 5, a temperature control arrangement 741 may be located along the travel path T of substrate 105 downstream from the liquid removal element 744, with the temperature control arrangement 741 being representative of, and/or comprising at least some of substantially the same features and attributes as the temperature control arrangements as previously described in association with at least FIGS. 1-4.

[0066] As further shown at 729 in FIG. 5, in some examples an image 152 on substrate 105 (following the heating at 728) is transferred at a transfer station 781 , which comprises at least some of substantially the same features and attributes as one of the previously described transfer stations (e.g. 181 in FIG. 1 ; 381 in FIGS. 3-4). For illustrative simplicity, FIG. 5 depicts a transfer station 781 like transfer station 181 in FIG. 1. Accordingly, as shown in FIG. 5, an image 152 formed of ink particles 134 on substrate 105 is advanced along travel path T toward nip 151 , at which rolling contact is made with image formation medium 157 as supported via rotating impression drum 153 to transfer the image 152 onto the image formation medium 157. [0067] 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.

[0068] FIG. 6 is a diagram including a side view schematically representing an example image formation device 800, which comprises at least one example implementation of the image formation device 700 of FIG. 5. Accordingly, in some examples, the image formation device 800 comprises at least some of substantially the same features and attributes as earlier described example image formation devices (e.g. 300, 500), while further comprising a charge emitter 740 and a liquid removal element 744 located along the travel path T of substrate 309 (on rotatable drum 308) between the fluid ejection device 110 and dryer 370. Moreover, in a manner similar to that represented in FIG. 5, the charge emitter 740 of image formation device 800 in FIG. 6 emits charges (e.g. 743 in FIG. 5) 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. 5. As in the example of FIG. 5, the liquid carrier 132 may be a non-aqueous fluid. [0069] Moreover, in a manner similar to that represented in FIG. 5, the liquid removal element 744 of image formation device 800 in FIG. 6 is to remove the liquid carrier 132 from the substrate 309 while leaving the ink particles 134 in their intended pattern to form an image on the substrate.

[0070] In some examples, as shown in FIG. 6, the image formation device 800 comprises a temperature control arrangement 841 comprising at least some of substantially the same features and attributes as the temperature control arrangement 341 as described in association with at least FIG. 3 and more generally as described in association with at least FIGS. 1-2.

[0071] FIG. 7A is a block diagram schematically representing an example image formation engine 950. In some examples, the image formation engine 950 may form part of a control portion 1100, as later described in association with at least FIG. 7B, such as but not limited to comprising at least part of the instructions 1111. In some examples, the image formation engine 950 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. 1-6 and/or as later described in association with FIGS. 7B-8. In some examples, the image formation engine 950 (FIG. 7A) and/or control portion 1100 (FIG. 7B) may form part of, and/or be in communication with, an image formation device.

[0072] In general terms, the image formation engine 950 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. 1-6 and 7B-8.

[0073] As shown in FIG. 7A, the image formation engine 950 may comprise a fluid ejection engine 952, a charge emitter engine 957, a liquid removal engine 958, and/or temperature control engine 980.

[0074] In some examples, the fluid ejection engine 952 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 order to at least partially form an image on the substrate 105. The formed image may later be transferred to an image formation medium.

[0075] In some examples, the charge emitter engine 957 is to control operation of a charge emitter (e.g. 740 in FIGS. 5, 6) 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. 5-6 and/or various examples throughout the present disclosure.

[0076] In some examples, the image formation engine 950 may comprise a temperature control engine 980 to control operation of at least one heater and/or sensor to control a temperature of an image formation medium to enhance transfer of a formed image from a substrate (e.g. intermediate transfer member) to the image formation medium, among other features.

[0077] In some examples, the temperature control engine 980 may comprise a heating parameter 982 to implement control, and/or tracking of, heating of an image formation medium, an impression drum, a substrate (e.g. intermediate transfer member), and/or elements supporting the substrate. Such elements may comprise a rotatable drum or array of rollers. In some such examples, the heating parameter 982 may operate in cooperation with a location parameter 986 regarding a location within the image formation device at which the heating is performed and/or in cooperation with a type parameter 988 regarding a type of heating (e.g. heated air, infrared, heated roller, etc.).

[0078] In some examples, the temperature control engine 980 may comprise a sensing parameter 984 to implement control, and/or tracking of, sensing a temperature of an image formation medium, an impression drum, a substrate (e.g. intermediate transfer member), and/or elements supporting the substrate. In some such examples, the sensing parameter 984 may operate in cooperation with a location parameter 986 regarding a location within the image formation device at which the sensing is performed and/or in cooperation with a type parameter 988 regarding a type of sensing (e.g. infrared, other).

[0079] It will be understood that, in at least some examples, the image formation engine 950 is not strictly limited to the particular grouping of parameters, engines, functions, etc. as represented in FIG. 7A, such that the various parameters, engines, functions, etc. may operate according to different groupings than shown in FIG. 7A.

[0080] FIG. 7B is a block diagram schematically representing an example control portion 1100. In some examples, control portion 1100 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, heating elements, sensing elements, user interface, instructions, engines, parameters, functions, and/or methods, as described throughout examples of the present disclosure in association with FIGS. 1-7A and 7C-8. In some examples, control portion 1100 includes a controller 1102 and a memory 1110. In general terms, controller 1102 of control portion 1100 comprises at least one processor 1104 and associated memories. The controller 1102 is electrically couplable to, and in communication with, memory 1110 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, heating elements, sensing 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 1111 stored in memory 1110 to at least direct and manage depositing droplets of ink particles (within a liquid carrier), directing charges onto ink particles, removing liquids, heating, sensing, etc. as described throughout the examples of the present disclosure in association with FIGS. 1- 7 A and 7C-8. In some instances, the controller 1102 or control portion 1100 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 1111 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 950 in FIG. 7A.

[0081] In response to or based upon commands received via a user interface (e.g. user interface 1120 in FIG. 7C) and/or via machine readable instructions, controller 1102 generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller 1102 is embodied in a general purpose computing device while in some examples, controller 1102 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, heating elements, sensing elements, user interfaces, instructions, engines, functions, and/or methods, etc. as described throughout examples of the present disclosure.

[0082] 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 1110 of control portion 1100 cause the processor to perform the above-identified actions, such as operating controller 1102 to implement the formation of an image, heating, sensing, 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 1110. The machine readable instructions may include a sequence of instructions, a processor-executable machine learning model, or the like. In some examples, memory 1110 comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller 1102. 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 1102 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 1102 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 1102.

[0083] In some examples, control portion 1100 may be entirely implemented within or by a stand-alone device.

[0084] In some examples, the control portion 1100 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 1100 may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion 1100 may be distributed or apportioned among multiple devices or resources such as among a server, an image formation device, and/or a user interface. [0085] In some examples, control portion 1100 includes, and/or is in communication with, a user interface 1120 as shown in FIG. 7C. In some examples, user interface 1120 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. 1-7B and 8. In some examples, at least some portions or aspects of the user interface 1120 are provided via a graphical user interface (GUI), and may comprise a display 1124 and input 1122.

[0086] FIG. 8 is a flow diagram schematically representing an example method 1200. In some examples, method 1200 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, heating elements, sensing elements, control portion, user interface, etc. as previously described in association with FIGS. 1-7C. 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, heating elements, sensing elements, control portion, user interface, etc. other than those previously described in association with FIGS. 1- 7C.

[0087] As shown at 1202 in FIG. 8, in some examples method 1200 may comprise moving a substrate along a travel path. As shown at 1604 in FIG. 8, method 1200 may comprise depositing, via a fluid ejection device, droplets of ink particles within a liquid carrier to form an image on the substrate.

[0088] As shown at 1206 in FIG. 8, in some examples method 1200 may comprise transferring the formed image onto an image formation medium in a nip at which an impression drum is in rolling contact with the substrate.

[0089] As shown at 1208 in FIG. 8, in some examples method 1200 may comprise heating the image formation medium prior to the transfer at the impression drum.

[0090] In some examples, method 1200 may further comprise emitting airborne charges onto the deposited droplet to induce electrostatic migration toward, and electrostatic fixation of, the ink particles relative to the substrate as the formed image. In some such examples, method 1200 also comprises prior to the transferring, removing at least the liquid carrier from the substrate while leaving the electrostatically fixed ink particles on the substrate.

[0091] In some examples, method 1200 may further comprise heating the impression drum and sensing, via an infrared sensor, a second temperature of at least a surface of the heated impression drum.

[0092] 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 substrate to move along a travel path; a fluid ejection device to deposit droplets of ink particles within a liquid carrier to form an image on the substrate; an impression drum in rolling contact with the substrate to receive transfer of the formed image from the substrate onto an image formation medium; and a first heater positioned to heat the image formation medium prior to the transfer at the impression drum.

2. 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 substrate as the formed image.

3. The image formation device of claim 2, comprising: a liquid removal element downstream from the charge emitter and upstream from the impression drum to at least partially remove the non-aqueous liquid carrier from the substrate while leaving the electrostatically fixed ink particles on the substrate.

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

5. The image formation device of claim 1 , comprising: a first infrared sensor to sense a first temperature of the image formation medium prior to entry of the image formation medium into the nip.

6. The image formation device of claim 5, comprising: a second heater in thermal communication with the impression drum to heat at least the impression drum and the image formation medium.

7. The image formation device of claim 6, comprising: a second infrared sensor positioned external the impression drum to sense a second temperature of at least a surface of the impression drum.

8. The image formation device of claim 1 , wherein the first heater comprises at least one of: at least one heated roller; an infrared lamp; and an air heater to direct heated air onto the image formation medium.

9. The image formation device of claim 1 , comprising: a second heater in thermal communication with the impression drum to heat the image formation medium.

10. An image formation device comprising: a 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 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 substrate as the formed image; a liquid removal element downstream from the charge emitter and upstream from the impression drum 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 substrate to receive transfer of the formed image from the substrate to an image formation medium; and a first heater positioned to heat the image formation medium prior to the transfer at the impression drum.

11. The image formation device of claim 10, comprising: a first infrared sensor to sense a first temperature of the substrate prior to entry into the nip; a second heater in thermal communication with the impression drum to heat the impression drum and the substrate; and a second infrared sensor positioned external to the impression drum to sense a second temperature of at least a surface of the impression drum.

12. The image formation device of claim 10, wherein the substrate at least partially defines an intermediate transfer member, and the substrate comprises an outer surface of at least one of a rotatable drum and a belt.

13. A method comprising: moving a substrate along a travel path; depositing droplets of ink particles within a liquid carrier onto the substrate to form an image on the substrate; transferring the formed image from the substrate onto an image formation medium in a nip at which an impression drum is in rolling contact with the substrate; and heating the image formation medium prior to the transfer at the impression drum

14. The method of claim 13, comprising: emitting airborne charges onto the deposited droplet to induce electrostatic migration toward, and electrostatic fixation of, the ink particles relative to the substrate as the formed image; and prior to the transferring, removing at least the liquid carrier from the substrate while leaving the electrostatically fixed ink particles on the substrate.

15. The method of claim 13, comprising: heating the impression drum; and sensing, via an infrared sensor, a second temperature of at least a surface of the heated impression drum.