The inkjet printer for plastic bags attains micron precision (±25μm) at 120,000 drops per second (droplet size 6-14pl) with a piezoelectric nozzle combined with a UV-LED curing system (395nm wavelength, 12W/cm² power), A wear-resistant surface layer of thickness as low as 3-5μm is formed on the surface of non-polar plastic such as PE/PP. According to the 2023 “Packaging and Printing Technology Yearbook”, after ASTM D3359 cell test, UV ink adhesion on LDPE plastic bags with a surface energy of 32mN/m reached up to 4B (shedding area <5%), while ordinary water-based ink only 1B (shedding area >65%). A European supermarket chain case shows that after 500 times of -18 ° C friction cold chain bag printed by the inkjet printer for plastic bag, scanning success rate of bar code remains 99.7%, and the return rate reduces by 18%.
The spirit of anti-fouling is quick curing technology, and the curing speed of UV ink is 99.8% in 0.2 seconds (3-5 seconds in the traditional hot drying process), speeding up the speed of the production line to 120 m/min (limited to 50 m/min with solvent-based ink). Statistics quantified from Japanese packaging companies for food show that after conversion to inkjet printer for plastic bag, one production line can double the daily production capacity from 80,000 bags to 220,000 bags with a reduction of energy use by 62% (1.8kW vs 4.7kW per hour). With regards to chemical stability, the chemical resistance of the UV ink oil has been remarkably improved, upon ISO 21702 test after olive oil contact for 24 hours, ΔE<1.5, for compliance with the FDA 21 CFR 175.300 standard for food contact material.
Pretreatment surface system increases PE bag surface energy from 31mN/m to 44mN/m by corona discharge (15kW power, 20kHz frequency) and reduces the ink contact angle from 105° to 35°. A medical device packaging project showed that after gamma sterilization (25kGy dose) of pre-treated dialysis solution bags, 98% label clarity was maintained and FDA 510(k) review duration was reduced by 40%. Dynamic viscosity control technology (ink viscosity 18-22cP) and close-loop ink supply system, deviation of the ink drop point is controlled at ±0.1mm, thus the lowest recognizable two-dimensional code size minimized from 3×3mm to 1×1mm, and density of information 400% higher.
Cost analysis indicates that plastic bag’s inkjet printer has combined operating cost 37% less than flexo printing. Taking a Chinese daily chemical company as an example, the usage rate of UV ink is up to 98% (65% for flexographic printing), reducing the 520,000 yuan annual ink purchase cost, and lowering the hazardous waste treatment by 89% (from 1.2 tons per month to 0.13 tons), avoiding the risk of pollution penalty. The 2024 Smithers report stated that the global plastic packaging inkjet printing market will develop at an annual rate of 11.4%, of which anti-rubbing technology contributes 68%, and the size of related equipment is expected to be more than $2.4 billion in 2027. The promoters are the new Amazon FBA label requirements (friction tolerance ≥1000 times) and the regulation of VOC emission limits (≤5g/m³) by REACH policies.