The SEIKO SPT510 and SPT1020 sit at the same point on the press — the 72 mm print bar of a wide-format solvent machine — and they share the same nozzle pitch and the same ink interface. Shops still mix them up when ordering, and then discover the difference the expensive way. This is what actually separates the two heads, and how to tell which one your machine expects.
The short answer
The SPT510 is a 510-nozzle, 180 dpi head that fires a fixed 50 pL drop. It is the classic grand-format head: dense, opaque laydown and famously hard to clog.
The SPT1020 is 1,020 nozzles at 360 dpi native, firing a fixed 35 pL drop. In practical terms, it is two SPT510-35PL heads merged into a single casting — which is exactly why it keeps the 510’s reliability while doubling native resolution.
If you are choosing between them rather than replacing like for like, resolution is the deciding factor. If your work is banners at three metres viewing distance, the 510’s larger drop does the job and costs less. If you are printing anything that will be read up close — point-of-sale, vehicle graphics, fine sign work — the 1020 gives you twice the native resolution from the same bar width.
Drop size, resolution and what each is actually good at
| Specification | SEIKO SPT510 | SEIKO SPT1020 |
|---|---|---|
| Nozzles | 510 | 1,020 (two interleaved rows) |
| Nozzle pitch | 141.1 µm (1/180 inch) | 185 npi per row |
| Print swathe | approx. 71.8 mm | 71.9 mm |
| Native resolution | 180 dpi (up to 720 dpi interlaced) | 360 dpi (up to 720 dpi effective) |
| Drop volume | Fixed 50 pL | Fixed 35 pL |
| Firing frequency | 6–8 kHz | 6.46 / 8.29 kHz |
| Jetting speed | — | 4.2 m/s |
| Greyscale | None (binary) | None (binary) |
| Physical | 126.3 × 99.2 × 32.9 mm, approx. 200 g | All-steel, internal damper and filter |
| Part number | IRH1513U (50 pL) | SN2535G0-2010 |
Both heads are binary: they fire one drop size and build tone by dot placement rather than by varying drop volume. That is a deliberate trade. Fixed-drop heads have fewer failure modes and far lower ink-system demands than greyscale heads of the same era, which is why this platform ran in production shops for two decades.
A 50 pL drop lays down roughly twice the ink volume of a 35 pL drop. On exterior banners and backlit signage that density is the point — the whites stay opaque and the colour stays solid even when the print is lit from behind. Move to finer work and the same drop becomes a liability: you can see the dots, and edge definition suffers. The 1020’s 35 pL drop with twice the nozzle count is the compromise that made it the standard upgrade.
Speed, ink delivery and the hardware you do not see
At first glance the frequencies look similar — both peak around 8 kHz — but the 1020 fires from twice as many nozzles, so its throughput in millilitres per second is materially higher. The head also carries hardware aimed squarely at production uptime:
- An internal ink damper and filter, which keeps supply steady and stops debris from reaching the nozzle plate.
- A real-time temperature and voltage control module that adjusts the drive as the head warms, holding drop volume stable through a long shift instead of drifting.
- A TICKLING function that shakes ink at the nozzles so they do not dry out between jobs — the single most useful feature on a machine that stops and starts all day.
- A non-wetting nozzle plate and all-steel construction, which resist ink build-up and stand up to industrial environments.
The 1020 is normally paired with heating and negative-pressure ink delivery to keep viscosity in range. The 510 mounts downward, horizontally or vertically on X/Y/Z datum points and takes an optional heater; it is the less demanding installation of the two.
Fitting and interchangeability
Both heads sit on the SII Printek 510 platform and share the mechanical footprint and ink interface, which is why a 1020 can replace a 510 in a machine designed for it. The same 510 body is also built in 35 pL and 80 pL versions, and SII still lists the platform in its current catalogue as the 510BN.
Do not assume the swap is free, though. Moving from 510 to 1020 doubles native resolution, and the printer’s RIP, print mode and calibration have to be reconfigured accordingly. In practice it is a straight swap for shops that already run a 1020-capable machine, not for one that was built around a 510.
Which printers each head fits
SPT510: Infiniti / Challenger FY-3208N/Q and FY-3278 series, Phaeton UD-3278, CrystalJet CJ-4000 and CJ-6000, Xenons X5310.
SPT1020: Infiniti / Challenger FY-3208GS and FY-3266 series, Icontek M5 / M7 and TW-3306 / TW-3308, Phaeton UD-3266, CrystalJet S6306.
If your machine appears in both lists, the head fitted is what decides it — check the label, not the brochure.
A third option: the SPT1024GS
If you need more than fixed drops give you, the SEIKO SPT1024GS keeps the same 72 mm swathe but steps up to 1,024 nozzles at 360 npi with variable 7–35 pL drops in six steps (7 / 14 / 21 / 28 / 35 pL) at up to 30 kHz. Instead of a fixed drop it varies volume within a single pass, which smooths gradients and removes the banding that fixed-drop heads show on photographic and textile work. It is the head to move to when someone is actually going to look closely at the output.
How to choose
- Read the label on the head you are replacing. IRH1513U means 510; SN2535G0-2010 means 1020.
- Match the drop size, not just the model. The 510 platform also exists at 35 pL and 80 pL — the mechanical fit is the same but the print result is not.
- Check the ink system before you order. Both heads run oil, UV and solvent inks, but the ink circuit and pressure settings differ between a 50 pL and a 35 pL installation.
- Ask us. Send your printer model and a photo of the head label through the contact form and we will confirm the exact part, from the full SEIKO printhead range.
FAQ
Can I fit an SPT510 where an SPT1020 was?
They share a platform and footprint, and both are stocked as genuine originals — SPT510 50PL and SPT1020 35PL. But you would be halving native resolution, so this only makes sense if the job profile changed. Confirm the print mode with your machine builder first.
Which head is more clog-resistant?
Both are binary heads with generous drop sizes and a robust piezo design, and both are known for running through long idle periods without nozzle loss. The 1020 adds the TICKLING function and an internal filter, which help further in stop-start production.
Is the 510 discontinued?
Not in practice. SII Printek still lists the platform in its current catalogue as the 510BN, and the legacy SPT510 and SPT1020 remain among the most widely fitted heads in grand-format printing — which is why we hold both in stock as 100% original, serial-numbered, QC-tested units.
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