40U vs 50U vs 60U vs 85U: A Practical CIJ Nozzle Size Guide

CIJ nozzle size affects the range of characters a printer can produce, but the largest nozzle is not automatically the best choice. Fine component codes, multi-line packaging information and bold marks on building materials each require a different balance of character height, definition, line count, ink and production speed.

This practical guide compares the 40U, 50U, 60U and 85U options used across the DAYSJET range and explains how to choose the right configuration for a real production line.

What does “U” mean in a CIJ nozzle specification?

In CIJ product specifications, 40U, 50U, 60U and 85U are commonly used as shorthand for the nominal nozzle diameter in micrometres. The nozzle forms the ink stream from which controlled droplets are created. Its size helps define the printer's useful range, but it does not determine print quality by itself.

The finished code also depends on ink formulation, character matrix, droplet control, printhead distance, line speed, substrate and maintenance condition. Always compare the complete printer specification and test the intended message rather than selecting by nozzle number alone.

40U: fine, compact coding

A 40U configuration is well suited to small, precise characters where available print area is limited. Typical applications include electronics, cosmetics, pharmaceutical packaging, small components and fine cable marking.

The DAYSJET 1770-40 specifies character heights from 0.8 to 10 mm and speeds up to 280 m/min under the stated configuration. This makes it a useful starting point when the priority is compact code size rather than the boldest possible mark.

50U: flexible multi-line information

A 50U option provides a practical middle ground for detailed packaging messages. It can suit applications that need more lines of text, larger characters or a balance between definition and visibility.

The DAYSJET 1770-48 uses a 50U nozzle, supports one to eight print lines and specifies character heights from 1.0 to 15 mm. For labels or packaging that must carry several fields—such as a date, lot, plant code and traceability data—the available line capacity can be more important than nozzle size alone.

60U: a versatile industrial standard

A 60U configuration is a versatile choice for many production environments. It can balance readable character height, stable general-purpose coding and compatibility with a broad set of message types.

The DAYSJET 1770-60 supports one to five lines, character heights from 1.5 to 12 mm and content including text, barcodes and DataMatrix codes. The 1770-OPQ also uses a 60U pigment configuration for high-contrast marks on dark substrates. These are different ink systems, so the choice should follow both code geometry and surface colour.

85U: larger, highly visible characters

An 85U configuration is appropriate when a larger, more prominent mark is required. Potential applications include cartons, pipe, cable, timber and building materials where operators must read the code easily or where the available print area is larger.

The DAYSJET 1770-85 specifies one to five print lines and character heights from 1.2 to 15 mm. A larger nozzle can support a bolder visual result, but the message should still be tested for edge definition, drying and ink consumption at the planned line speed.

Side-by-side comparison

Published speed values are measured under defined print settings. Actual production speed can change with the character matrix, number of lines, code content and installation. Treat the specification as a shortlist tool, then verify the exact message in a sample-print test.

Five questions that identify the right nozzle

1. What is the required character height?

Measure the available print area and specify both the minimum legible height and maximum permitted height. Avoid choosing a range that barely covers the requirement; leave room for code position and product variation.

2. How many lines and data elements are needed?

A nozzle choice must work with the required character matrix and line count. Multi-line messages may need a different setup from a one-line date code, even when the overall print height looks similar.

3. What is the actual production speed?

Record normal and maximum conveyor speed, product spacing and any acceleration. Test the final message at the fastest real condition, not only at an average speed.

4. Which substrate and ink will be used?

Ink behaviour changes the appearance of the mark. A smooth, light package using dye ink presents a different challenge from dark rubber requiring opaque pigment ink. Nozzle, ink and surface must be validated as one system.

5. How will the code be inspected?

Human-readable text, camera inspection and DataMatrix scanning have different tolerances. Use the intended viewing distance or scanner to judge the sample, and test curved or reflective products from realistic angles.

Why a production sample is essential

A specification sheet cannot reproduce every combination of message, material and line condition. Print the real code on the real product, then evaluate size, contrast, edge quality, drying, adhesion and scanner performance. Where possible, run samples at minimum and maximum speeds and after the environmental exposures the product will encounter.

DAYSJET also offers platforms such as the 1760 and 1780 with multiple configuration options. Browse the full DAYSJET product range, or contact DAYSJET with your code sample, character height, substrate and line speed for a nozzle and ink recommendation.