There are a number of technologies used for inkjet printing. Commonly CIJ (Continuous Ink Jet) is used for smaller printing up to 8mm and is also suitable for high speed production lines.
Newer technology using HP cartridges called TIJ gives clearer codes and due to the recent ink formulations and head technology is now able to adhere not only to porous surfaces but also non-porous. This technology reduces the need for ongoing maintenance and solvents.
Older technology is known as DOD (Drop on demand) suitable for cartons or large bags.