Why doesn’t high resolution printing bleed on corrugated paper boxes?

Many clients have a question about high-resolution inkjet printing: Since the paper box absorbs ink, why are the QR codes and small characters printed on it so clear?

In fact, "no smudging" is not because the cardboard does not absorb ink, but because the high-resolution PIJ technology using a piezoelectric nozzle, through the tiny deformation of the piezoelectric crystal, the size and ejection position of each ink droplet can be precisely controlled.

This is also the reason why the PIJ inkjet printing performs better than the traditional CIJ printing. Next, we will explain the specification reasons from several aspects.

1.Small and precisely controlled droplet size

As we mentioned above, the PIJ printing system can control the volume of ink droplets, making the droplets typically only a few picoliters (pL), which is much smaller than the CIJ inkjet coding.

1. · Smaller ink droplets → Less ink deposited per single deposition.
2. · The ink does not form excessive penetration in the paperboard fibers.
3. · The edges are sharper, and the outlines of characters and QR codes are clearer.

In contrast, for the purpose of adapting to high-speed flight, CIJ inkjet coding requires continuous spraying of larger ink droplets, which is more prone to feathering and bleeding on porous materials.

2.Fast dry ink specially designed for porous materials

NAXJET offers a selection of environmentally friendly UV-curable inks and fast-drying inks, formulated to:

1. ·Be rapidly absorbed by the paperboard surface rather than spreading laterally;
2. ·Exhibit low lateral wicking;
3. ·Form a stable, uniform ink layer on the paper fiber surface.

Simply put, the ink tends to be vertically absorbed rather than horizontally spread.

3.Precise Non-Contact Printing (High Precision Spray Printing)

The PIJ nozzle maintains a stable printing distance from the carton, and together with a high-precision encoder or photoelectric sensor, it achieves precise positioning.

Each ink droplet lands precisely at the designated position, minimizing overlap and deviation, even when printing:

1. 2D QR Codes
2. GS1-128 barcode
3. Characters smaller than 2 mm
4. High-density Logo

It can also maintain a high level of edge clarity and scanning recognition rate.

4. The surface of the cardboard box is inherently suitable for the PIJ technology.

Although corrugated cardboard has a certain ink-absorbing property, compared to non-absorbent materials such as plastic and metal, it can quickly fix the ink droplets. As long as the size of the ink droplet and the ink formula match, the paper fibers will play a "lock-in ink" role instead of causing severe smudging.

For common packaging materials such as kraft paper boxes, white card boxes, and coated corrugated board, high-resolution inkjet printing usually can achieve stable printing results.