A code printer is a vital piece of equipment in modern manufacturing and logistics, responsible for marking products with dates, batch numbers, barcodes, and QR codes. While the term covers several technologies, the core principle remains the same: precisely depositing ink onto a surface without physical contact. Understanding the dominant technologies—Continuous Inkjet (CIJ) and Thermal Inkjet (TIJ)—reveals the engineering behind this everyday process.

Continuous Inkjet (CIJ): The Workhorse for High-Speed Lines

CIJ technology is built for speed and endurance on fast-moving production lines. The process begins in a pressurized reservoir where ink is pumped through a tiny nozzle, creating a continuous stream of ink droplets. These droplets then pass through an electrode, where a precise electrical charge is applied to each one based on the desired print pattern. The charged stream then flies through an electrostatic field, which deflects the charged droplets onto the product surface. Unused, uncharged droplets are caught and recirculated back into the system, minimizing waste. This method is exceptionally fast and can handle challenging environments, printing on uneven surfaces at distances of several centimeters.

Thermal Inkjet (TIJ): Precision for High-Resolution Coding

In contrast to CIJ, Thermal Inkjet (TIJ) technology operates on a "drop-on-demand" principle, firing ink only when needed. The heart of a TIJ printer is its disposable print cartridge, which contains hundreds of microscopic nozzles. Behind each nozzle is a tiny resistor. When an electrical current pulses through this resistor, it heats up incredibly quickly, vaporizing a minute amount of ink to create a bubble. The expansion of this bubble forces a single ink droplet out of the nozzle and onto the substrate. The entire cycle—heating, bubbling, ejecting, and collapsing—happens in microseconds. TIJ is renowned for producing high-resolution, laser-quality codes and graphics, making it ideal for clear expiration dates on primary packaging or high-density barcodes.

The choice between these technologies depends on the application. CIJ excels in high-speed, industrial environments where ruggedness and long-distance printing are key. TIJ dominates where exceptional print quality, ease of use, and lower maintenance are priorities. By harnessing either charged deflection or controlled thermal expansion, code printers provide the silent, automated link between your database and your product, ensuring traceability and compliance across countless industries.