Staggered UV Curing for Inkjet Print Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional UV curing of inkjet printed ink faces challenges in precision control, leading to light spillage and undesirable gloss differentials due to the transition between low and high power UV sources, causing image artifacts in inkjet printing.
Innovation Solution
A system and process that utilize pinning lamps with controllable shutters to gradually increase UV energy from low to high levels, ensuring sufficient pinning of light-sensitive ink before final curing, thereby reducing or eliminating image artifacts across various inks and printing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low powered pinning UV lamps are used first and then high powered curing UV lamps, then sufficient pinning of light sensitive ink is achieved, but undesirable gloss differentials and image artifacts occur due to light spillage during transition
Solution Approach 1:
The patent employs a dynamic UV lamp system that transitions from low power pinning mode to high power curing mode in a controlled sequence. The system dynamically adjusts lamp power levels and positioning to first pin the ink sufficiently, then gradually increase power for curing while minimizing light spillage effects that cause gloss differentials and image artifacts.
Solution Approach 2:
The system performs preliminary pinning action using low powered UV lamps before applying high powered curing lamps. This preliminary pinning ensures the ink is sufficiently set and resistant to bleeding, allowing the subsequent high power curing to proceed with minimal adverse effects from light spillage during the transition.
2Reliability
If high powered UV lamps are used for curing, then complete polymerization of ink is achieved, but light spillage occurs into areas not requiring curing, causing gloss differentials
Solution Approach 1:
The curing process is segmented into distinct phases: initial pinning phase with low power UV lamps, intermediate transition phase with gradually increasing power, and final curing phase with high power lamps. This segmentation allows complete polymerization to be achieved while controlling light spillage to minimal levels that do not cause gloss differentials.
Solution Approach 2:
The UV lamp system employs periodic action by cycling through different power levels and exposure durations. The system periodically adjusts lamp power from low to high and back, allowing the ink to absorb UV energy in controlled increments rather than all at once, thereby achieving complete curing without excessive light spillage effects.
3Reliability
If UV lamps are positioned close to the print area, then pinning effectiveness is improved, but control precision over UV delivery is reduced
Solution Approach 1:
The patent introduces an intermediary control system including adjustable lamp positioning mechanisms and power regulation circuits. These intermediaries allow precise control over UV delivery by mediating between the lamp's inherent output and the actual energy reaching the print area, enabling close positioning for effective pinning while maintaining measurement precision through controlled variables.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively controls UV energy delivery to prevent light spillage and artifacts, ensuring consistent curing and reducing gloss differentials by gradually increasing pinning energy to a threshold before full curing, enhancing the quality of inkjet prints.
Implementation Method 1
ultra-violet (UV) curing of inkjet printed ink... pinning and polymerizing ink, using different levels of UV dosage
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Enhanced printing systems, structures, and processes provide enhanced pinning of light sensitive inks before curing, such as to avoid artifacts, e.g. between colors, and/or between regions of different color densities. One or more pinning lamps are controlled or otherwise configured to deliver pinning energy over an interval, e.g. over a period of time or over a percentage of completion, to a pinning threshold level, which may be stored and/or determined. In some exemplary embodiments, the pinning energy is increased linearly over an interval. Other exemplary embodiments provide a stepped or staggered increase in applied pinning energy. An additional level of pinning may preferably be provided after pinning and before curing, at an energy level over the first pinning threshold, and below the curing threshold. The enhanced printing systems, structures, and processes reduce and/or eliminate moderate or large transitions of UV light energy, which may otherwise cause image artifacts.