Wide for­mat inkjets: inks

CMYKWide for­mat inkjet print­ers are every­where — they cov­er all wide for­mat mar­kets and they’re used for both tech­ni­cal doc­u­ments and graph­ic arts applications.

There are four pri­ma­ry ink types used with wide for­mat inkjets:

  • Aque­ous
  • Sol­vent (from full sol­vent to eco-solvent)
  • UV
  • Latex

Let’s take a look at each of these pri­ma­ry ink types, their pros and cons. 

Aque­ous (water-based)

Aque­ous inkjet print­ers have been around for a good long time and rep­re­sent the bulk of the mar­ket. Among all types of wide for­mat inkjets, they have the low­est equip­ment pur­chase price but they’re also the slow­est printers.

They pro­duce excel­lent prints at high res­o­lu­tions, but their run­ning costs can be high and they require coat­ed media for many appli­ca­tions. For exam­ple, you’ll need spe­cial media and lam­i­na­tion for prints to be used out­doors — mean­ing an addi­tion­al pro­duc­tion step and addi­tion­al costs.

There are two aque­ous ink types: dye and pigment.

Dye:

In dye inks the water dis­solves dye mol­e­cules to form a “solu­tion”. These dyes eas­i­ly soak into the media.

Pros:
  • Pro­duces bril­liant, sat­u­rat­ed col­ors — dye inks pro­vide a wide col­or gamut.
  • Good for every­day print­ing of doc­u­ments, proofs, or pho­tos that will be kept in a con­trolled, indoor environment.
  • Envi­ron­men­tal­ly friendly.
Cons:
  • Fades quick­ly in UV light. Lam­i­na­tion or coat­ing can help reduce this.
  • Not water­proof. Their prints can smear — even when already dry if they’re exposed to mois­ture or high humidity.
  • Not meant for long-term out­door prints.

Pig­ment:

Pig­ment inks use col­orant par­ti­cles that stay sus­pend­ed in the liq­uid. The par­ti­cles tend to sit on top of the media, rather than soak­ing down into it.

Pros:
  • More fade- and water-resis­tant than dye inks.
  • More sta­ble than dye inks. They’re good for archival pur­pos­es when print­ed on suit­able media and stored under ide­al con­di­tions (lit­tle light exposure).
  • Envi­ron­men­tal­ly friendly.
Cons:
  • More expen­sive than dye inks.
  • Residues can clog print­heads if allowed to dry out.
  • Not meant for long-term out­door prints.

Sol­vent

Sol­vent inks use pig­ments sus­pend­ed in a chem­i­cal sol­vent. There are full sol­vent and eco-sol­vent vari­a­tions. The sol­vents “bite into” the media sub­strate so that the inks bonds securely.

They pro­duce very durable, light-fast prints that are most­ly used for out­door appli­ca­tions like ban­ners, sig­nage, and vehi­cle wraps.

Pros
  • Pro­duces very durable, scratch resis­tant prints.
  • Good for print­ing out­door applications.
  • Wider range of media than aque­ous inks.
Cons:
  • They con­tain VOC — volatile organ­ic com­pounds — which present health and safe­ty prob­lems. These must be dealt with in the workplace.
  • Fumes — the work­place requires spe­cial ven­ti­la­tion equip­ment (eco-sol­vent inks are less toxic).
  • Requires com­plete print dry­ing before final use or post-pro­duc­tion fin­ish­ing oper­a­tions like mount­ing and laminations.

Latex

Latex inks use water as their main ingre­di­ent, like the pig­ment-based aque­ous inks men­tioned above. The dif­fer­ence here is that they add latex or a resin to the solu­tion to sus­pend the pig­ment par­ti­cles. The ink forms a latex film on the media — after it’s heat­ed with a radi­ant heater in the printer.

Pros:
  • Durable for indoor or out­door use with­out lam­i­na­tion (although that can increase their longevity).
  • Flex­i­ble and stretch­able — good for fab­ric sig­nage and vehi­cle wraps.
  • Non-tox­ic, non-flammable.
  • No need for spe­cial han­dling or ventilation.
Cons:
  • Requires pre-print and post-print heaters in the print­er — increas­ing pow­er consumption.
  • Small­er col­or gamut than aque­ous (dye-based) inks — they’re com­pa­ra­ble to low-sol­vent inks.

UV-Cur­able

UV inks mix col­ored pig­ments into a syn­thet­ic resin. Each UV print­er sprays the ink onto the media, then “cures” it by pass­ing the print under an ultra­vi­o­let light. The light actu­al­ly changes the chem­i­cal com­po­si­tion of the ink and helps it adhere to the substrate.

Pros:
  • Can be print­ed onto a very wide vari­ety of sub­strates — even onto met­al, wood, card­board, foam board, or glass.
  • Does not require coat­ed media.
  • Does not require lam­i­na­tion for exte­ri­or posters, ban­ners, or signage.
  • Does not release chem­i­cals into the environment.
Cons:
  • Print­ed mate­r­i­al can not be stretched or bent — mean­ing they’re not good for vehi­cle wraps or fabrics.
  • Good sys­tems are expensive.
  • Less col­or gamut than aque­ous or sol­vent inks.

As always, like all oth­er con­sid­er­a­tions in the wide for­mat print world, if you’re in the mar­ket for a new inkjet print­er, you must con­sid­er your appli­ca­tions before mak­ing your choice. There’s no “one size fits all” wide for­mat print­er that does it all for all appli­ca­tions. Some have broad­er appli­ca­tions ranges than oth­ers, but you just might need more than one printer!

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