Last Updated: 2026-09-17
One smudged batch code can pull a food shipment off the shelf. How does a CIJ printer work? It forces ink through a tiny nozzle, breaking the continuous stream into charged droplets that an electric field deflects onto a moving surface to form characters at high speed.
Overview
Continuous inkjet (CIJ) printing is a non-contact coding method used on production lines worldwide. A printhead projects a steady stream of ink droplets, charges selected droplets, and guides them onto packaging material. Unused ink returns to the reservoir for recirculation, making the process efficient for long runs.
CIJ systems print on plastic, glass, metal, and curved surfaces without touching the product. Food, beverage, and pharmaceutical lines rely on them for date codes, lot numbers, and shift identifiers. The technology follows ISO 9001 quality management practices in regulated industries.
In CIJ printing, the printhead never touches the substrate. This separates it from contact methods like thermal transfer or stamping, which require direct pressure on the packaging material.
How It Works
The CIJ printing cycle follows four stages:
| Stage | What Happens |
|---|---|
| 1. Ink pressurization | A pump pushes ink from the reservoir through the printhead nozzle at steady pressure |
| 2. Droplet charging | A charge electrode assigns an electrical charge to each droplet as it breaks off |
| 3. Deflection | Deflection plates create an electric field that steers charged droplets to the target |
| 4. Recovery | Uncharged droplets bypass the field and return to the ink reservoir via a gutter |
The nozzle diameter typically ranges from 40 to 70 microns. Ink viscosity is maintained by adding make-up fluid, which replenishes solvents lost to evaporation and keeps the ink at the correct thickness for consistent droplet formation.
A piezoelectric crystal vibrating at high frequency creates the droplet breakoff. The frequency determines print resolution and speed. Most CIJ printers operate at line speeds up to 5 meters per second. Learn more about the broader category of inkjet printing on Wikipedia.
Applications
CIJ printers handle coding on fast-moving production lines where contact printing would slow output. Common uses include:
- Expiry dates on milk bottles and beverage cans
- Lot numbers on pharmaceutical blister packs
- Batch codes on snack bags and frozen food cartons
- Shift codes on industrial components
The non-contact nature lets CIJ print on wet, oily, or uneven surfaces. Make-up fluid keeps ink viscosity stable during extended runs, reducing nozzle clogs and maintenance downtime.
The SHICAI Approach
SHICAI manufactures CIJ printers for industrial coding lines that need consistent uptime. Our printhead designs simplify nozzle cleaning, reducing maintenance intervals. The make-up fluid system auto-adjusts viscosity based on temperature and run time, keeping ink at the correct thickness across shifts. Each unit ships with documentation aligned to ISO 9001 quality management standards for regulated production environments.
Related Questions
- How does a CIJ printer work on curved surfaces?
- The deflection plates adjust droplet trajectory in real time, allowing the printhead to print on bottles and cans without direct contact.
- What ink does a CIJ printer use?
- CIJ printers use solvent-based inks formulated for fast drying on non-porous surfaces. Make-up fluid replenishes evaporated solvents to maintain viscosity.
Next Steps
- Read our guide to continuous inkjet printing for a deeper look at the technology.
- Need help matching a CIJ printer to your line? Contact us for a free fit check with no obligation.
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