"Flex or UV" sounds like a technology question. It is really a question about who your customers are and what they ask you for, and buyers who start with the technology usually end up with the wrong machine for their actual business. Here is how to work through it properly.
What flex solvent printing is actually good at
A flex solvent machine like the Konica 512i is built for volume, roll media and speed: hoardings, banners, shop boards, wedding and event backdrops. It survives dusty premises and unstable power better than most alternatives, which matters more in this region than a spec sheet suggests. If your customers are signage shops, event organisers or anyone who orders in bulk on a deadline, flex solvent is the machine most of them are actually asking for, whether they know the term or not.
Eco solvent is the milder version of the same technology, lower odour and sharper on vinyl and backlit film, and the fairer comparison for anyone weighing it against UV for indoor work: less smell than standard solvent, but still liquid ink cured by evaporation rather than UV light, so the running-cost and surface differences below still apply the same way.
What UV printing is actually good at
A UV flatbed or UV roll to roll machine prints directly onto rigid and unusual surfaces: acrylic, ACP, glass, wood, tiles, phone cases, as well as roll media with instant cure and none of the solvent smell. It opens a different customer base entirely, retail and interior work, promotional items, anyone who wants a print on an object rather than a banner. Where flex work is often priced by the square foot in volume, UV work tends to be priced by the piece, at a different margin structure, because the customer is paying for a finished object, not a printed sheet.
The question that actually decides it
Do not start by asking which machine prints better. Start by asking what you are already turning away. A flex shop that keeps getting asked for acrylic signage or promotional items is leaving that revenue on the table every time it says no. A shop doing occasional rigid work on a slow UV unit is spending more time per job than the work is worth. The machine that fits is the one that matches the work already walking in the door, not the one with the more impressive specification sheet.
Running cost looks different on each side
Flex running cost is dominated by ink consumption at volume, roughly one litre per 1,000 square feet on a solvent machine, plus the wear parts that come with continuous roll work. UV running cost is shaped differently: the white ink channel is consumed separately from CMYK and at its own rate, instant cure removes drying time from the job cycle, and rigid media costs vary far more by job than roll media does. Neither is simply cheaper than the other, they are structured differently, which is exactly why comparing "cost per machine" without comparing the work each one produces misses the point.
Most established workshops end up with both
The two are not really competitors. A shop that starts on flex solvent because that is what its first customers ask for often adds a UV flatbed once rigid and promotional enquiries become frequent enough to justify it, because the two machines serve two different order books rather than replacing each other. Pairing a UV flatbed with a CO2 laser cutter, for instance, lets a workshop close an acrylic signage job in house end to end, cutting and printing without sending either half out. The sequencing question is not "flex or UV", it is which one your current customers are already asking for, and which one is next.
What we actually recommend
We do not sell against a specification sheet, and we will not tell a shop that only ever runs banners to buy a UV flatbed because it is the higher margin machine on paper. Send us the jobs you are currently quoting and the ones you are currently turning down, and we will run them and show you the difference on a call rather than a brochure describing it. Most buyers start by asking for a specific model and end up ordering the configuration that actually pays back fastest for the work they do, and that is sometimes the cheaper machine, not the more advanced one.