Two UV flatbed quotations arrive the same week. One is built around Ricoh Gen-6 printheads, the other around Seiko industrial heads, and the price gap is smaller than you expected. The temptation is to treat the head as a component detail and decide on bed size and delivery date. That gets it backwards. On a UV flatbed, the printhead sets the resolution ceiling, the throughput floor, the ink you are allowed to run, the gap you can print across, and the biggest single line item in your five-year maintenance budget. Everything else on the machine is built around it.
Ricoh Gen 6 vs Seiko printhead on a UV flatbed printer is not a quality ranking. It is a fit question, and the honest answer depends on whether you are printing flat sheet at high resolution or three-dimensional parts across a variable gap.
What a printhead specification actually says
Five numbers describe an industrial piezo head. Get all five, from the head manufacturer's datasheet rather than the machine builder's brochure, before you compare anything.
Nozzle count and row structure. Nozzles are arranged in rows, and the number of rows determines how colours or channels are split across a single head. A head with four rows can be run as four separate channels at a quarter of the nozzle count each, or as one channel at full count with the rows interleaved for higher effective resolution. The same head therefore produces very different numbers depending on how the machine builder wires it — which is why nozzle count alone tells you nothing until you know the channel assignment.
Native drop volume, in picolitres. The smallest drop the head can eject. Smaller drops give finer detail and smoother gradients; larger drops lay down more ink per pass and cover faster. This is the central trade in the whole comparison.
Greyscale levels. A binary head fires one drop size: a dot is on or off. A greyscale head can fire several drop sizes per addressable position by ejecting multiple sub-drops that merge in flight — commonly two to eight levels. Greyscale is why a modern head can hold a smooth sky gradient without visible dot structure at moderate resolution.
Firing frequency, in kHz. Drops per second per nozzle. Throughput is roughly nozzles multiplied by frequency; a head that fires faster covers more area at the same pass count.
Ink compatibility window. Viscosity range, operating temperature, and whether the ink path recirculates. This is the one that quietly decides your consumable cost, because it decides which inks you can legitimately run.
The head families, side by side
| Attribute | Ricoh Gen-5 / Gen-6 class | Seiko / SII Printek industrial class |
|---|---|---|
| Typical published nozzle count | ~1,280, arranged in four rows | ~508 / ~1,024 / ~1,536 depending on family member |
| Native minimum drop | Small — commonly published in the ~5–7 pl region | Larger — binary variants commonly at ~12, ~15 and ~35 pl; greyscale variants exist |
| Drop control | Greyscale, multi-drop | Both binary and greyscale members in the family |
| Best at | Fine detail, gradients, photographic work on flat sheet | Ink laydown, coverage speed, robustness across a bigger gap |
| Tolerance of head-to-substrate gap | Lower — small drops decelerate faster | Higher — larger, heavier drops carry momentum further |
| Typical machine role | Rigid flatbed, high-resolution sheet and board | High-clearance, 3D parts, industrial and heavy-coverage work |
| Recirculating ink path | Available on recirculating variants | Available on some family members |
Treat every figure in that table as the band to check, not as a contract value. Head families are revised, and machine builders fit different members of the same family. The rule that holds is the shape of the trade: small drops buy detail and cost speed; large drops buy speed and gap tolerance and cost fine gradation.
Why the high-clearance machine uses a different head
This is the part that is rarely explained, and it is the reason the two head families exist side by side in the same product range rather than one replacing the other.
A drop leaving a nozzle travels a few millimetres of open air before it lands. It is decelerating the whole way, because air drag scales with surface area while momentum scales with mass. A small drop has a poor ratio of mass to surface area, so it slows quickly, gets pushed around by the airflow the moving carriage drags with it, and arrives late and off-target if the gap grows. A big drop punches through.
On flat sheet the gap is small and constant, so the fine head wins outright. On a raised, uneven or three-dimensional part the gap varies across the surface — and once the gap varies, a fine drop's placement error varies with it. That is why high-clearance machines are typically specified with the larger-drop industrial head family: not because the buyer wants coarser output, but because the physics of throwing a drop across a bigger and less predictable gap rewards drop mass.
Longrun's published range splits along exactly this line: the 2513 flatbed is listed with Ricoh Gen-6 printheads for sheet and board work, and a separate high-clearance model is listed with Seiko industrial heads, described as printing onto thick, raised and uneven objects that standard flatbeds cannot reach. If your job mix genuinely spans both, that is a two-machine or two-configuration discussion, not a settings change — the same reasoning that makes two quotes for apparently the same specification differ.
Channels: how heads become colours, white and varnish
Head count is a throughput and capability decision disguised as a component count.
A basic configuration assigns one head per process colour: four heads, CMYK. Adding white gives you the ability to print on clear, dark and metallic substrates — an under-layer of white before the colour on transparent acrylic, or over-printed white behind colour when the piece is viewed through the substrate. Adding varnish gives you a clear layer for gloss, matte and raised tactile effects. Longrun's listing states that white and varnish layers are available on the flatbed line; how many heads carry those channels on a specific build is a per-quotation question.
Two consequences buyers miss:
More heads per colour is the only honest way to go faster at the same quality. If a machine doubles its heads per channel, it can lay the same ink in half the passes. Speed claims that do not change head count are claims about pass count, and pass count is a quality setting — see the next section.
White ink is a maintenance obligation, not a feature. White UV ink is pigmented with titanium dioxide, which is roughly four times the density of the carrier fluid. It settles. A machine with a non-recirculating white channel needs the ink agitated and the channel purged on a schedule, or the pigment drops out in the line and in the head and you lose nozzles. Heads and ink systems with through-flow recirculation exist precisely to solve this. If white is central to your work, ask whether the white channel recirculates and what the daily start-up routine is, and put the answer in the training plan alongside the rest of your installation, commissioning and operator training arrangements.
Pass count is where speed claims come from
A quoted square-metres-per-hour figure means nothing without the pass count and print mode attached. As a working rule, doubling the passes roughly halves throughput and buys you two things: more overlap between passes, which averages out any individual nozzle's weakness, and finer effective dot placement.
| Print mode | Relative throughput | What it is for |
|---|---|---|
| 2–4 pass | Fastest | Backlit-free signage, board, coverage work viewed at distance |
| 6 pass | Roughly half of a 4-pass mode | General production, the mode most shops actually run |
| 8–12 pass | Quarter or less | Close-viewed retail graphics, gradients, sample and proof work |
When you compare two quotations, force both onto the same footing: same file, same substrate, same pass count, same resolution, and ask for the square-metre-per-hour figure at that mode. Otherwise you are comparing a 4-pass number against a 6-pass number and concluding the wrong thing. This is the same comparison discipline the broader buyer's guide to UV flatbed printers from China applies to the rest of the specification, and the bed-size arithmetic in what a 2500 x 1300 mm table actually holds is the other half of the same throughput calculation.
The five-year cost the head decides
Printheads are consumables with a long and unpredictable life. They fail by losing nozzles, one or a few at a time, until the loss can no longer be hidden by pass overlap. Nothing about that is a defect — it is the wear mode of the technology. What varies is how fast it happens and what a replacement costs.
Four things shorten head life, and three of them are operator-controlled:
- Ink outside the specified viscosity and temperature window. Cheap ink that is nominally compatible but thicker than specified makes the piezo work harder and deposits residue in the channel. This is the most common cause of premature failure and the most common warranty exclusion.
- Head strikes. A lifted or warped substrate hitting the nozzle plate. One strike can end a head.
- UV backscatter. Stray cure energy reflecting off a glossy white or mirrored substrate back up into the nozzle plate, curing ink at the nozzle exit. It is why gloss white acrylic and polished metal are harder on a machine than matte board, and why lamp shielding and lamp-to-head spacing are worth asking about.
- Idle time without a maintenance cycle. UV ink cures with energy, not with drying, but it still thickens and settles. A machine that sits over a long holiday without a purge routine can come back with a blocked channel.
The economics are simple arithmetic that almost nobody does before signing. Ask for the replacement price of a single head, in writing, in the quotation currency. Multiply by the number of heads fitted. That figure — the full head set — is the real number, because heads tend to age together. Industrial greyscale heads are routinely a four-figure US dollar item each, and prices move, so get the current one rather than a remembered one. Then ask three commercial questions: how long is the head warranty, is it in months or in litres or in square metres, and does it survive the use of third-party ink.
That last question is where the money is. A machine sold with a chipped, closed ink system may carry a fuller head warranty and a consumable price you cannot negotiate; an open ink system lets you buy ink competitively and usually shifts head risk onto you. Neither is wrong. Both need to be a conscious choice, priced across five years, not discovered after the first ink order.
Common questions
Is a Ricoh head better than a Seiko head?
They are optimised for different jobs. The Ricoh-class greyscale heads give finer drop control and suit high-resolution work on flat sheet; the Seiko-class industrial heads lay more ink per pass and tolerate a larger and more variable head-to-substrate gap, which is what three-dimensional and high-clearance work needs. Pick by job mix, not by badge.
Can I choose the printhead when I order?
Machine builders working on an ODM basis normally configure the head to the application. Longrun's published capability statement says its in-house engineers configure machines to a buyer's bed size, printhead and feeding needs, and its build description names Ricoh and Seiko heads. The specifics — how many heads, which family member, and how channels are assigned to CMYK plus white and varnish — are per-quotation questions, so ask for them in writing rather than assuming a standard build.
How many heads do I need?
Enough channels for the work: four for CMYK, five or six if you need white and varnish. Beyond that, extra heads per channel buy speed at the same quality. Decide the channels first from your substrate list — clear acrylic and dark board both push you toward white — then decide how much speed you are willing to pay for.
What does "high resolution" mean on a UV printer quote?
Usually an addressable resolution built up from pass count and interleaving, not the head's native nozzle pitch. A machine can address 1,200 dpi with a head whose rows sit at a much coarser native pitch, by printing more passes. Ask for the native nozzle pitch, the number of passes used to reach the quoted resolution, and the throughput at that mode.
What to ask the supplier next
Take these eight to the quotation stage. They cost nothing to ask and they are hard to renegotiate after a deposit.
- Exact head model and family member — the manufacturer's part number, not "Ricoh Gen-6 class". Then read the head maker's own datasheet.
- Number of heads fitted and channel assignment: how many per colour, and which heads carry white and varnish.
- Native drop volume in picolitres, greyscale drop levels, and firing frequency for that configuration.
- Recirculation: does the ink path recirculate, and specifically how is the white channel kept in suspension?
- Ink: which ink is the machine profiled for, is the system open or chipped, and what is the price per litre landed in your market? An ink brand named verbally is worth nothing — get it on the specification sheet.
- RIP software and colour management: which RIP ships with the machine, is the licence transferable if you resell, and who supplies ICC profiles for your substrates?
- Head commercials: replacement price per head today, warranty term and how it is measured, nozzle-out threshold that triggers a warranty replacement, and whether third-party ink voids it.
- Curing: UV-LED array or arc lamp, and how the lamps are shielded from backscatter onto the nozzle plate.
Longrun Printing Machinery is a reasonable place to test those questions — a Shenzhen builder established in 2009, running UV flatbed, corrugated-carton digital and cylindrical lines, with a published range that puts Ricoh Gen-6 heads on the 2513 flatbed and Seiko industrial heads on the high-clearance model, machines sold from a single unit, same-day sampling on standard models, and remote and on-site setup, training and spare parts listed as part of the process. The head part numbers, the channel count and the replacement economics are not published figures — which is the point of asking. A supplier who answers all eight in writing is telling you something useful about how the machine was engineered, whatever the answers turn out to be.