Abstract:
Enhanced inks, and associated systems and processes are disclosed, wherein one or more enhanced inkjet layers are established in a work piece, i.e. a substrate. One or more of the inks comprise a selective photo absorber that allows UV curing, while absorbing incident UV light after production. In some embodiments, the selective photo absorber can be configured to absorb light at wavelengths less than 380 nm, while a photoinitiator in the ink can be activated by light having an average wavelength that is equal to or greater than 380 nm. Incident UVA and UVB light is readily absorbed by the cured enhanced ink layer, thus minimizing deleterious effects such as any of yellowing, loss of gloss, or cracking. The selective photo absorber can be used in one or more layers, and can be used on an outer protective inkjet layer.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to the field of printing systems, structures, and associated processes. More particularly, the invention relates to improved inks for use in printing systems. 
       BACKGROUND OF THE INVENTION 
       [0002]    Broad-spectrum ultraviolet radiation (UVR) includes three wavelength ranges, comprising UVA light, having a wavelength range of about 320 nm to 400 nm, UVB light, having a wavelength range of about 290 nm to 320 nm, and UVC light, having a wavelength range of 100 nm to 280 nm. Solar UV energy that reaches Earth comprises primarily UVA light, with a small amount of UVB light. No UVC light from solar radiation reaches the earth&#39;s surface, since UVC radiation is completely absorbed in the upper atmosphere, by ozone, molecular oxygen, and water vapor. 
         [0003]      FIG. 1  shows an exemplary conventional print job  10 , comprising one or more layers  16 , e.g.  16   a - 16   e,  of conventional ink that may be jetted onto a surface  14 , e.g.  14   a,  of a substrate  12 , wherein each of the layers  16  are typically cured by application of UV energy, which activates a photoinitiator that is included in the jetted ink. Print jobs that are produced using ultraviolet (UV) curable inkjet inks are commonly affected over time, by exposure to light. 
         [0004]    In conventionally cured inks and coatings, an arc lamp, with various types of undoped mercury or doped mercury lamps are used. These lamps emit light over a wide range of wavelengths, such as in the UVA spectrum, the UVB spectrum, and/or the UVC spectrum. This light is used to initiate cure reactions, using photoinitiators that absorb light in the emitted range. 
         [0005]    As seen in  FIG. 1 , light  20  can have one or more adverse effects  22  on such print jobs  10 . For example, pigments within the ink, even those that are considered to be stable to light, often fade over time, due to photo bleaching. Furthermore, light  20  can adversely affect  22  the acrylic polymer matrix that is formed when the ink is cured, and/or the underlying substrate  12 , which can result in undesired effects  22 , such as yellowing  22 , and over time, changes in gloss and/or physical changes, e.g. cracking. 
         [0006]    Weathering of inks and coatings often happens with exposure to light that can break bonds in the polymers or pigments. For example, many polymers are sensitive and degrade in the 290-345 nm range, and sunlight that reaches the earth has appreciable intensity at wavelengths above 300 nm. 
         [0007]    Currently, photo absorbers are often used to protect coatings and prints that are thermally or oxidatively cured. Photo absorbers are materials that absorb light that can otherwise lead to detrimental reactions, such as degradation. These materials are configured to absorb light in the ultraviolet (UV) spectrum, and do not affect the color of the coating or print. 
         [0008]      FIG. 2  is an exemplary graph  26  of deleterious affects of degradation of quality  28 , due to incident light, as a function of time  30 , for a coating or print  10  that is thermally or oxidatively cured, with  36  and without  34  the addition of UV absorption additive. As seen in  FIG. 2 , the quality  28  of a coating may degrade rapidly from exposure to incident light. Degradation of such coatings and print jobs  10  becomes even more pronounced with increasing exposure to light, such as if when the work product is located outdoors. As seen in the second graph  36  of  FIG. 2 , a print job  10  that includes a photo absorber is configured to maintain print quality  28  as a function of time  30 , by reducing the deleterious effects of incident light. 
         [0009]    Acrylate coatings that are cured with e-beams can also use photo absorbers, without concern for a reduction in the cure rate. 
         [0010]    In contrast to printers that provide thermal or oxidative curing, many current print systems are configured to cure ink with UV light, wherein the inks contain photoinitiators to initiate curing when controllably exposed to the light. The majority of these printers to date have used doped or undoped mercury arc lamps to generate sufficient UV light to initiate curing. The arc lamps generate a broad spectrum of light where a large part of the available light energy is generated at wavelengths lower than 380 nm. 
         [0011]    In the last few years, there has been increasing use of LED lamps as sources of UV light. These LED sources are narrow in bandwidth. The most powerful LED lamps currently available generate light with the band centered around 380 to 400 nm. 
         [0012]    While UV absorbers are commonly used in other printing environments, to block harmful light from affecting prints or coatings, the use of such UV absorbers would block UV light that is used for curing in conventionally cured print systems, and hence cannot be used effectively to protect such prints from the ambient light that causes degradation. This is because the majority of the energy available for curing in arc lamps overlaps the wavelengths that cause photodegradation of the film, and are blocked by UV absorbers, While small amounts of UV absorbers may be used, while still allowing curing, the use of greater amounts of UV absorbers, such as to lend full protection for the print, does not enable curing. 
         [0013]    Therefore, conventional UV print systems often use other methods of protection to increase the photostability of their prints, such as using radical scavengers within the ink. However, such methods do not fully replace the use of UV absorbers. 
         [0014]    It would therefore be advantageous to provide an LED curable ink that may be used in print systems that comprise UV curing, wherein the LED curable ink includes a photo absorber that increases the photostability of the resulting print job, while retaining full curability from LED light sources. The development of such an LED curable ink would be a major technological breakthrough. 
         [0015]    It would also be advantageous to provide such an LED curable ink that is readily configured to be used in a wide variety of print systems and associated processes, without undue modification. The development of such an LED curable ink would constitute a further technological advance. 
       SUMMARY OF THE INVENTION 
       [0016]    Enhanced ink compositions, and associated systems and processes are disclosed, wherein one or more enhanced inkjet layers are established in a work piece, i.e. a substrate, wherein one or more of the inkjet layers comprise a selective photo absorber that allows UV curing, while absorbing incident UV light after production. For example, in some embodiments the selective photo absorber can be configured to absorb light at wavelengths less than 380 nm, while a photoinitiator in the ink can be configured to be controllably activated by light having an average wavelength that is equal to or greater than 380 nm. Subsequent exposure of the work piece to incident UVA and UVB light, having an average light spectrum of less than 380 nm, is readily absorbed by the layer, thus minimizing deleterious effects such as any of yellowing, loss of gloss, or cracking. The selective photo absorber can be used in one or more layers, such as for any of pigmented or unpigmented layers. In some embodiments, the selective photo absorber can be used on an outer protective inkjet layer. The enhanced inks can be configured for a wide variety of printing systems having UV curing mechanisms. The enhanced ink may also preferably be configured for printing systems having UV pinning. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  shows an exemplary conventional print job that is subjected to light; 
           [0018]      FIG. 2  shows an exemplary graph of deleterious affects of degradation of a print job over time, as a function of incident light, with and without the addition of UV absorption additive; 
           [0019]      FIG. 3  shows a partial cross section of a print job having one or more enhanced ink layers; 
           [0020]      FIG. 4  is a schematic diagram of an exemplary enhanced ink composition; 
           [0021]      FIG. 5  is a chart that shows absorbance as a function of wavelength for an exemplary ink additive having relatively low absorption of light in a curing spectrum, and relatively high absorption of light in an ambient spectrum; 
           [0022]      FIG. 6  is a schematic diagram of an exemplary system for delivering and curing one or more layers of enhanced ink; 
           [0023]      FIG. 7  is a schematic diagram of an alternate exemplary system for delivering and curing one or more layers of enhanced ink; 
           [0024]      FIG. 8  is a schematic diagram of an exemplary system for delivering and curing one or more layers of enhanced ink, wherein the substrate is supported on a platen; 
           [0025]      FIG. 9  is a flowchart of an exemplary process for delivering and curing one or more layers of enhanced ink; and 
           [0026]      FIG. 10  is a high-level block diagram showing an example of a processing device that can represent any of the systems described herein. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0027]      FIG. 3  shows a partial cross section of a print job  40  having one or more ink layers  46 , e.g.  46   a - 46   e,  on at least one surface  44 , e.g.  44   a,  of a substrate  42 , wherein one or more of the ink layers  46  comprises ink  60  ( FIG. 4 ) that is enhanced with the inclusion of a selective photo absorber  66  ( FIG. 4 ). The selective photo absorber  66  is configured to allow curing  150  ( FIG. 9 ) from exciting light  123  ( FIG. 6 ) delivered from a light source  122 , e.g. LED curing assemblies  122  ( FIG. 6 ), while allowing increased photostability for the finished, i.e. cured, print job  40  when subjected to light  20 . 
         [0028]    In some embodiments, each of the ink layers  46  is enhanced with a selective photo absorber  66 . In some alternate embodiments, only the top layer  46 , e.g.  46   e,  such as an LED curable clear coat  46   e,  is enhanced with a selective photo absorber  66 , such as to provide a protective upper layer that is configured to substantially absorb incident UVA and UVB light. In some embodiments, at least the first layer  46   a  is enhanced with a selective photo absorber  66 , such as to provide an undercoat layer  46   a  that substantially protects a work piece  42  from incident UVA and UVB light. 
         [0029]      FIG. 4  is a schematic diagram of an exemplary enhanced ink composition  60 , which comprises at least a photoinitiator  64  and a selective photo absorber  66  within a suitable carrier system  62 , having a photocurable vehicle  63 . The enhanced ink composition  60  may be substantially colorless, or may include one or more colorant  68 , such as any of one or more dyes  72 , one or more pigments  70 , and/or any mixture thereof. In some embodiments, the enhanced ink composition  60  may comprise other additives, dispersions, and/or particles  74 , and/or other components that protect from photodegradation of the films, such as but not limited to hindered amine light stabilizers (HALS). 
         [0030]    The carrier system  62  is largely a photocurable resin, comprised of a selection of monomers and oligomers selected so as to have the correct physical properties to be jetted from a print head  104 . The carrier system  62  is also typically selected to yield the required physical properties after cure, and to cure at sufficiently high speeds for the printer  100  ( FIG. 6 ,  FIG. 7 ,  FIG. 8 ). While the carrier system  62 , i.e. a photocurable vehicle  62 , is normally comprised of a mixture of (meth)acrylates, the carrier system  62  can comprise any photo-polymerizable chemistry. 
         [0031]    In some embodiments of enhanced print jobs  40 , a outer layer, e.g.  46   e,  can comprise a substantially colorless layer  46 , such as to protect one or more prior layers  46 ,  46   a - 46   d,  and/or the substrate  42  itself. In such embodiments, the protective outer layer  46 , e.g.  46   e,  can be any of transparent, especially clear, or substantially clear. As well, the protective outer layer  46  can be configured to provide any of a matte, semi-gloss, or glossy appearance. 
         [0032]    For embodiments of enhanced inks that include one or more colorants  68 , the number and kinds of colorants can depend upon the enhanced ink  60  being formulated. In some embodiments, the enhanced ink  60  can comprise Thorn about 2 percent to about 10 percent of colorant, by weight of the composition. The amount of pigment can depend, at least in part, on the colorant  68  used. 
         [0033]    Some embodiments of enhanced inks  60  can comprise one or more colorants  68  that are based upon a set of colorants, such as but not limited to a set comprising cyan, magenta, yellow, and black (CMYK) colorants  68 . Other embodiments of enhanced inks  60  can comprise more complicated colorant packages, and can be formulated in many colors, including colors that can be configured to provide other qualities, such as but not limited to metallic or pearlescent qualities. Some combinations of the enhanced inks  60  can be configured to print full color variable images on a substrate  40 . 
         [0034]    Various inorganic and organic dyes  72  and/or pigments  70  can be used with the enhanced ink  60 . In general, pigments  70  can have a maximum particle size that is small enough to avoid clogging the ink jets during printing. As well, the pigments  70  can have a narrow particle size distribution. Non-limiting examples of pigments  70  that can be useful with some embodiments of enhanced inks  60  can comprise any of CI Pigment Yellow 74, 93, 95, 109, 110, 120, 128, 138, 139, 151, 154, 155, 173, 180, 185, and 193; C.I. Pigment Orange 34, 36, 43, 61, 63, and 71; C.1. Pigment Red 122, 202, 254; CI Pigment Blue 15:3, 15:4; C.I. Pigment Violet 19, 23, and 33; and C.I. Pigment Black 7. Non-limiting examples of dyes  72  that can be useful with some embodiments of enhanced inks  60  comprise any of Orasol yellow 2RLN, Orasol yellow 2GLN-M, Savinyl yellow, Savinyl scarlet RLS, Orasol red BL, and Orasol blue GN. 
         [0035]      FIG. 5  is a chart  80  that shows absorbance  84  as a function of wavelength  82  for an exemplary selective photo absorber  66  having relatively low absorption of light in a curing spectrum  90 , and relatively high absorption of light, e.g.  20 , in an ambient spectrum  88 . 
         [0036]    For example, the enhanced ink  60  can comprise a selective photo absorber  66  that is configured to absorb light in a region  88  that is mainly below  390  nanometers. Such an enhanced ink  60  can readily be used in a inkjet printing system  100  for which the exciting cure light  123  ( FIG. 6 ) comprises one or more light emitting diodes (LEDs)  122  that have a light spectrum  90  is centered at 390 nm and above. 
         [0037]    Under these conditions, the light absorption of the UV light absorber  66  does not interfere with the exciting light  123  that is activated to cure  150  the jetted ink film  46 , e.g.  46   e.  The light absorber  66  can be added in high concentrations, thus protecting the polymers and pigments, all which tend to absorb light strongly below 390 nm. For example, polypropylene bonds are affected by light that has a wavelength lower than 370 nm. The selected light absorbers  66  filter out the more energetic low wavelength light  20 , and thus protect the film  46  and pigments from photo degradation. 
         [0038]    The exemplary absorption data  86  seen in  FIG. 5  is based on light absorber  66  comprising 2-Hydroxy-4-n-Octoxybenzophenone. In an exemplary current embodiment of the enhanced ink  60 , the selective photo absorber  66  comprises BLS  531  UV absorber, available through Mayzo Inc., of Suwanee, GAa., which is configured to provide strong absorption of UV radiation in the 300 nm to 400 nm region  88 . Other embodiments of photo absorbers that can be used in enhanced inks  60  can comprise any of triazine, benzotriazole, and/or benzophenone derivatives that are substituted or bridged with polyoxyalkylene groups. 
         [0039]    Further examples of commercially available UV Absorbers based on 2-Hydroxyphenyl-s-triazine are Tinuvin 479 (available through BASF Corporation, Resins Division, of Wyandotte, Mich.), where the absorbance drops to baseline at a wavelength below 390 nm. UV absorbers based on 2-(2-hydroxyphenyl)-Benzotriazole, such as Tinuvin 99-2 (also available through BASF Corporation), absorb light slightly above 390 nm, but will interfere only slightly with an LED lamp  122  whose wavelength is centered at 395 nm. 
         [0040]    It should be appreciated by those skilled in the art, as a discussed above, that LED lamps that are currently available generate light with the band centered around 380 to 400 nm. The discussion above regarding  FIG. 5  considers the case where a photo absorber that is included in the ink absorbs light, for example, below 390 nm. 
         [0041]    In another illustrative embodiment, such as for one or more light emitting diodes (LEDs)  122  that generate exciting light  123  within a range of 365 to 410 nm, the photoinitiator  64  can be chosen or otherwise configured to be controllably activated within the range of 365 nm to 410 nm. In this embodiment, the photo absorber can be configured to absorb light having an average wavelength that does not substantially overlap with the range. For instance, the photo absorber can be configured to absorb light at wavelengths that are largely or substantially below that of the range. 
         [0042]      FIG. 6  is a schematic diagram of an exemplary system  100  for delivering and curing one or more layers  46 , e.g.  46   a - 46   e,  of enhanced ink  60 , such as for but not limited to single pass or scanning systems  100 . While the exemplary system  100  seen in  FIG. 6  in regard to a drum system for supporting a flexible substrate  42 , e.g. paper or film, it should be understood that the compositions  60 , systems  100 , and associated processes  140  ( FIG. 9 ), can readily be applied to a wide variety of printing systems and substrates or other work pieces  42 . 
         [0043]    The exemplary system seen in  FIG. 6  illustrates some of the exemplary controls and subsystems, e.g.  116 ,  108 ,  124 , for controlled movement of a print drum  114 , controlled delivery of ink drops  106 , and controlled LED curing  150  ( FIG. 9 ). The exemplary system embodiment seen in  FIG. 6  can also preferably comprise one or more pinning stations  126 , with associated controls  128 . 
         [0044]    As seen in  FIG. 6 , movement of a print drum  114  can comprise an encoder  116  and a corresponding motor  118 , wherein the encoder  116 , such as linked to or associated with a central controller  110  having a processor associated therewith, e.g. such as processor  210  ( FIG. 10 ), provides a signal or otherwise communicates with the motor  118 , and wherein the motor  118  moves the print drum  114 , e.g. such as directly or indirectly through a drive mechanism  120 , to move the substrate  42 , such as in step increments, e.g. to provide a desired resolution with delivered ink drops  106 . 
         [0045]    As also seen in  FIG. 6 , an ink delivery system  108 , such as comprising ink cartridges, and associated plumbing, is typically driven by a central controller  110  and/or by local control, to controllably jet ink drops  106  from one or more of the print heads  104  onto the substrate  42 , such as in accordance with an incoming image signal  112 . 
         [0046]    As further seen in  FIG. 6 , one or more LED curing stations  122  are controlled by any of a central controller  110  and/or LED curing control  108 , to emit light from one or more LED elements, to cure, i.e. dry, delivered ink droplets  106  located on the substrate  42 . In some embodiments, LED curing assemblies  122  are configured to deliver exciting light  123  having a wavelength centered around 410 to 380 nm, and in some current system embodiments  100 , the LED curing assemblies  122  preferably have a wavelength centered around 385 to 400 nm. 
         [0047]    The exemplary LED printer  100  seen in  FIG. 6  can further comprise one or more LED pinning stations  126 , such as controlled by any of a central controller  110  and/or LED pinning control  128 , to emit light from one or more LED pinning elements, such as to provide sufficient power to control or stop the spread of the delivered ink drops  106  located upon the substrate  42 . 
         [0048]      FIG. 7  is a schematic diagram of an alternate exemplary system for delivering and curing one or more layers of enhanced ink, such as for a single pass roll to roll printer  100 , e.g.  100   a,  having an LED lamp assembly  122  on one side, wherein the system  100   a  is configured to move  132  the substrate  142 , such as supported by a platen  134 , under one or more print heads  104 , in the direction of the lamp  122 , between a first roll  131   a  and a second roll  131   b.    
         [0049]    As seen in  FIG. 7 , movement of the substrate  42  between the rolls  131 , e.g.  131   a,    131   b,  can be controlled through an encoder  116  and a corresponding motor  135 , wherein the encoder  116 , such as linked to or associated with a central controller  110  having a processor associated therewith, e.g. such as processor  210  ( FIG. 10 ), provides a signal or otherwise communicates with the motor  135 , and wherein the motor  135  rotates at least one of the rolls  131 , e.g.  131   b,  such as directly or indirectly through a drive mechanism  136 , to move the substrate  42 , such as in step increments, e.g. to provide a desired resolution with delivered ink drops  106 . 
         [0050]      FIG. 8  is a schematic diagram  137  of an alternate exemplary system  100  for delivering and curing one or more layers  46 , e.g.  46   a - 46   e,  of enhanced ink  60 , wherein the substrate  42  is supported on a platen  134 . The print heads  104  and LED assemblies  122  seen in  FIG. 8  are located within a print head assembly  139 . The exemplary printing system seen in  FIG. 8  can also preferably comprise one or more pinning stations  126 , with associated controls. 
         [0051]      FIG. 9  is a flowchart of an exemplary process  140  for delivering and curing one or more layers  46 , e.g.  46   a - 46   e,  of enhanced ink  60 , to produce an enhanced print job  40 , such as to preserve print quality  28  ( FIG. 2 ) over time  30  ( FIG. 2 ). 
         [0052]    As seen in  FIG. 9 , a print system  100  is provided  142 , which comprises at least one print head  104  that is configured for delivering  106  and ink jet ink  60  having a selective photo absorber  66  that is configured to absorb light in a first spectrum  88 , e.g. ambient light, while having reduced absorption in one or more other spectrums  90 , thus allowing a photoinitiator  64  to be properly activated by curing energy  150  and/or pinning energy  148 . The provided system  100  further comprises an energy delivery mechanism  122 , e.g. one or more LED curing assemblies  122 , and can further comprise pinning assemblies  126 . 
         [0053]    When a substrate  42  is provided, the print system  100  is configured to deliver  146  ink drops  106  from one or more of the print heads  104  onto at least a portion of the substrate  42 , such as to establish one or more layers  46 , e.g.  46   a - 46   e.  If so configured, he print system  100  can power  148  one or more pinning stations  126  to provide pinning energy to the delivered ink  106 , such as between the jetting  146  and curing of more than one layer  46 . The print system  100  is configured to power  150  one or more LED curing stations  122 , to cure the delivered ink  106 , which may optionally have been previously pinned  148 . If required  152 , 154 , such as based on a print system configuration  100 , or based on a print job  40 , the process  140  can return  156  to deliver  146  and cure  150  more layers  46 . If no additional layers  46  are required  158 . The process  140  ends  160 . 
         [0054]    The enhanced inks and coatings  60  address the extent of photostability attainable with conventionally cured UV inkjet inks using photo absorbers since the same wavelengths that interact with the photoinitiators and cure the inks are those that cause photodegradation and are absorbed by the UV absorbers. 
         [0055]    As well, the enhanced inks and coatings  60  can be loaded with large amounts of UV absorbers  66  in amounts limited only by other formulation constraints, such as viscosity and shelf life, and will not reduce the cure rate of the ink or coating  60 . This is in contradistinction to the case of the conventionally cured coatings or inks, where adding a UV absorber will reduce the amount of light available to initiate the photochemical reaction meant to cure the ink or film. 
         [0056]    Furthermore, the enhanced inks and coatings  60  can be delivered by a wide variety of existing printing systems  100 , as long as the LED curing assemblies  122  have an active wavelength that is compatible with the photoinitiator  64 . Therefore, no special equipment is required for most printing system implementations  100 . 
         [0057]    Although the enhanced LED curable inkjet inks, and associated systems and methods of use are described herein in connection with exemplary embodiments of print systems, the compositions and techniques can be implemented for a wide variety of printing and/or manufacturing systems and environments, or any combination thereof, as desired. 
         [0058]    For example, alternate compositions can be provided for a wide variety of printing, painting and/or manufacturing environments. For instance, a wide variety of work pieces can readily include one or more applied layers having relatively low absorption of curing or pinning energy, and relatively high absorption of ambient energy. 
         [0059]      FIG. 10  is a high-level block diagram showing an example of a processing device  200  that can represent any of the systems described above, such as the printing system  100 , the printing system  100   a,  the ink delivery system  108 , the drive system  116 , the pinning system  128 , and/or the curing system  124 , Any of these systems may include two or more processing devices such as represented in  FIG. 10 , which may be coupled to each other via a network or multiple networks. 
         [0060]    In the illustrated embodiment, the processing system  200  includes one or more processors  202 , memory  204 , a communication device  206 , and one or more input/output (I/O) devices  208 , all coupled to each other through an interconnect  210 . The interconnect  210  may be or include one or more conductive traces, buses, point-to-point connections, controllers, adapters and/or other conventional connection devices. The processor(s)  202  may be or include, for example, one or more general-purpose programmable microprocessors, microcontrollers, application specific integrated circuits (ASICs), programmable gate arrays, or the like, or a combination of such devices. The processor(s)  202  control the overall operation of the processing device  200 . Memory  204  may be or include one or more physical storage devices, which may be in the form of random access memory (RAM), read-only memory (ROM) (which may be erasable and programmable), flash memory, miniature hard disk drive, or other suitable type of storage device, or a combination of such devices. Memory  204  may store data and instructions that configure the processor(s)  202  to execute operations in accordance with the techniques described above. The communication device  206  may be or include, for example, an Ethernet adapter, cable modem, Wi-Fi adapter, cellular transceiver, Bluetooth transceiver, or the like, or a combination thereof. Depending on the specific nature and purpose of the processing device  200 , the I/O devices  208  can include devices such as a display (which may be a touch screen display), audio speaker, keyboard, mouse or other pointing device, microphone, camera, etc. 
         [0061]    Unless contrary to physical possibility, it is envisioned that (i) the methods/steps described above may be performed in any sequence and/or in any combination, and that (ii) the components of respective embodiments may be combined in any manner. 
         [0062]    The ink delivery, pinning, curing, and/or other system functions introduced above can be implemented by programmable circuitry programmed/configured by software and/or firmware, or entirely by special-purpose circuitry, or by a combination of such forms. Such special-purpose circuitry (if any) can be in the form of, for example, one or more application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), etc. 
         [0063]    Software or firmware to implement the techniques introduced here may be stored on a machine-readable storage medium and may be executed by one or more general-purpose or special-purpose programmable microprocessors. A “machine-readable medium”, as the term is used herein, includes any mechanism that can store information in a form accessible by a machine (a machine may be, for example, a computer, network device, cellular phone, personal digital assistant (PDA), manufacturing tool, any device with one or more processors, etc.). For example, a machine-accessible medium includes recordable/non-recordable media, e.g. read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; etc. 
         [0064]    Note that any and all of the embodiments described above can be combined with each other, except to the extent that it may be stated otherwise above or to the extent that any such embodiments might be mutually exclusive in function and/or structure. 
         [0065]    Although the present invention has been described with reference to specific exemplary embodiments, it will be recognized that the invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense.