Published 2026-09-14 · Last Updated: 2026-09-14 · SHICAI technical team · Industrial coding guide
One wrong head count turns a fast line into a reprint queue. A thermal inkjet printer in the S20 series covers 50.8 mm to 152.4 mm of print height by stacking 25.4 mm heads, so the choice between S20-2, S20-4 and S20-6 comes down to the code height you need and the conveyor speed you run.
How a Thermal Inkjet Printer Builds Print Height
A thermal inkjet head is a 25.4 mm cartridge, and the series builds height by seating more of them in one frame. Two heads give a 2-50.8 mm mark, four give 2-101.6 mm, and six reach 2-152.4 mm. Throw distance stays at 2-5 mm, so the mounting gap does not change as the frame grows.
All three models run at up to 120 m/min and take seven ink colours. The S20-2 and the S20-6 carry a 600dpi HD rating, and the S20-4 standalone is documented for metal, plastic, pipe, foam and carton. What separates them is how much of the product face you must cover.
Where Each Frame Fits on a Line
Two heads suit the ordinary case: a date or batch code on a carton end, printed in a band 50.8 mm tall or less. Most lines replacing a hand stamp sit here, and the frame mounts in a tight corner.
Four heads suit the awkward cases, where a code stacks several lines of text or carries a scannable symbol beside it. The spliced S20-4 joins heads to double print width, the usual answer when a bracket is already welded to the conveyor.
S20-2 vs S20-4 vs S20-6
| Model | Heads and print height | Speed | Where it earns its keep |
|---|---|---|---|
| S20-2 standalone | Two 25.4 mm heads, 2-50.8 mm | Up to 120 m/min | Short date and batch codes on carton ends and labels |
| S20-4 standalone | Four 25.4 mm heads, 2-101.6 mm | Up to 120 m/min | Multi-line codes on wider faces, documented for metal, plastic, pipe, foam and carton |
| S20-6 splicing | Six 25.4 mm heads, 2-152.4 mm | Up to 120 m/min | The tallest block in the series, on lines that already carry a mount |
Before you specify, list five numbers: the tallest code, the number of text lines, whether a symbol shares the mark, the fastest conveyor speed, and the mounting room available. Budget follows head count rather than features, so the published coding machine price guide is the better starting point for a range, and the droplet mechanism behind all three models is described in the public reference on inkjet printing.
SHICAI Build and Support Behind the Series
SHICAI builds coding equipment in China and sells factory-direct, so a head-count change is a configuration change rather than a new supplier. Machines ship to overseas lines with spares and support arranged for export markets, and the build is confirmed against ISO 9001 quality management certification on request. Staying inside one series also keeps the interface, the cartridges and the maintenance routine unchanged when a frame has to grow.
S20-6 online inkjet printer (splicing)
The flagship frame of the series: six heads in a spliced body for tall, wide marks on cartons, foam and pipe.
- Prints up to 120 m/min
- 2-152.4 mm print height with six spliced heads
- Weighs only 3.5 kg per unit
Head-Count Questions
- How many print heads does the S20-6 use?
- Six 25.4 mm cartridges in one spliced frame, which produces a 2-152.4 mm print height at up to 120 m/min.
- Can heads be added to an S20-2 after installation?
- Only if the frame was specified for it. Ask whether the build leaves room for more cartridges, and get that in writing.
- What does an S20 thermal inkjet printer cost?
- Quoted per configuration. Send the code, its height and your line speed, and we return a configuration price rather than a list figure.
Where to Go From Here
- If the tallest code you print stays under 50.8 mm, start with the S20-2 online inkjet printer (standalone).
- If a wide face or a spliced mount is the constraint, look at the S20-4 online inkjet printer (standalone) first.
- Send the code, the tallest height and your conveyor speed to kuangcy@126.com or +86 17625427465. We confirm the head count in writing and print a free sample on your own product before you order.
Related reading: what a batch code printing machine is used for.
