We don't have a correct answer for high-quality of digital printing. We just work in the right way of using current technology. The current as well as old technology serves as bridges to next up-to-dates technology. Here is Solvent Ink-based Materials.

Since a couple of years ago, much more attention has been paid on solvent-based digital printer. Domestic and overseas manufactures have kept researching and designing substrates package for solvent ink-based as well as water ink-based printer. So, the solvent ink-based material has a lot of potential for outdoor application. and it will likely gain a more considerable market share.

Outdoor Application with Solvent-Based Printer.
Many people have been considering digital printer technologies as the solution for outdoor application. Depending on the types of printheads, there are slight differences between wide-format printers. Inkjet printer with high-resolution provides the widest range of application of the others. In practice, it is virtually impossible to directly print graphic on flex-faced material and sheet used with water-based ink. So it requires printing onto the additional digital-printing materials. This includes PVC sheet, transparent paper, white film and synthetic material. Like color sheets, these substrates have adhesion on the rear side, which could be applied on any application. In the case of printing with water-based pigment and water-based dye, ink could not be completely absorbed into these materials, but sits on top of coated area. So it cannot offer long-lasting outdoor warranty without finishing like laminating. In addition, each material including flex-faced material, digital printing materials and laminate film has the different coefficient of thermal expansion. It could cause exfoliation between each material. More technically, in summer, high temperature enable PVC material to become swelled out little by little. Because each materials like flex-faced material, digital printing material and laminating sheet has a different coefficient of thermal expansion, moisture soaks into the gap caused by thermal expansion. For that reason, a majority of signmakers were impatient for the technology directly printing onto flex-faced material. In fact, airbrush-based printer does not have any problems mentioned above. Since Airbrush-based painting machines could do lower-resolution work than Inkjet printer, it is not suitable for in-door application. Finally, the specific type of printer, which provides high-resolution with inkjet printhead and prints directly onto flex-faced material, appears in the outdoor advertising market.

Competitive Market
Within the large-format digital printing industry, solvent-based printer technology was first introduced by the major printer manufactures like Vutek and Scitex. Along with these manufactures, Nur Mscroprinters came out with its the line of Presco and Salsa. D.G.I Inc. released Rex-62 and VT-92. Pentel introduced its Live Photo Jet: Skyjet of PCI Korea, Lamiless of Mutoh, SolvenJET of Roland, A-Zero of Creon and Arizona of Raster Graphics. More Interestingly, Korea-based manufactures re-designed foreign technologies by using solvent ink and developed Solventjet 1370 of Taeil System Inc. and JV-SolventJET of Maca system Inc. Since the latter half of 2000, solvent printer maker had made great strides in developing the inexpensive printer with about 6.56ft., width. For that reason, medium and small-sized type of solvent-based machines began to gain the its greater market share. That was why many companies started to research and develop the materials related to this type of machines.

Increasing Demand for Flex-Faced Material
As materials for solvent Inkjet printers, the widely-used material is flex-faced material, which have archived a rapid growth since the latter of 1980, and the material has expanded its market share for the last three or four year. The material manufactures, recently, estimated five or ten percent of total demand is for solvent printing. In an early stage, most of signmakers applied flexsheet as sheet adhesion as it is. However, as becoming familiar with the elements of solvent ink, they commenced developing an inexpensive flex-faced material, lowing intensity of illumination and elevating the ad effect for a night. The price range is different according to manufactures, most of them are provided more less 40% price than before. Because the flex-faced material is mainly made of PVC with feature sucking in solvent-based ink very well. In other words, water-based ink lies on the top of material after printing, yet, solvent ink intends to completely soak into the material, which require no finishing work. It guarantees long-lasting outdoor application.
Below is a picture for more easy understanding.

Finding the Right Solution.
With the ability of absorbing completely solvent-ink, the flex-faced material substrate is extensively used in sign areas such as roof sign, wall graphics and billboard etc, As explained above, it does not matter using a usual flex-faced material for solvent ink printing. However, the substrate for digital printing has its difficulty of using as sheet adhesion. Therefore, if a part of screen of sign should digitally printed and the rest is made of cutting sheet, usual flex-faced material is more desirable to sign application. In the case that a sign is produced by only digital printing, using digital printing flex-faced material enable signmaker to reduce the cost of production. Several manufactures are still exploring the research and development for quality of flex-faced materials for solvent-based ink.

Window and Vehicle Application.
Another major substrate for solvent-based ink is adhesive film including color sheet, white film and transparent sheet. Adhesive film is made of PVC element as well, and solvent inks eat into the substrate as well as flex-faced material. Unlike flex-faced material, high performance on color is considered more important than intensity of illumination. There are some substrates available for easy attachment and removal for the wind or vehicle application.

Newly-developed substitute.
All materials described above are made of PVC element. One of the important application areas of digital printer is digital banner. There is significant difference between digital banner and PVC-based materials. Basically, digital banner is produced with cloth. Because ink could run on a banner cloth and tent cloth, these material is not suitable for digital printing. So, the specific cloth should be formulated for solvent digital printing. In manufacturing process, all cloth materials should be top coated so that water-based ink could lies on the coated area without ink's spreading on the cloth.

1) Materials for solvent-based ink is mainly made of PVC Resin.
2) ~ 5) In the case of applying prints on flex-faced materials, the final prints doesn't work for the outdoor application.
10)~14) Prints produced with Solvent-based ink guarantees long-lasting outdoor application without any finishing touch.