An Eco-Innovative Green Design Method using the Theory of Inventive Problem Solving and Importance–Performance Analysis Tools—A Case Study of Marker Pen Manufacturing

This study explores innovative designs for the cap of a marker pen, aiming to address the issues of cap loss and ink evaporation during marker pen usage. This study applies intrinsic safety, universal design and TRIZ as research methods. TRIZ has great potential to address most of the Sustainable Development Goals (SDGs) relevant to conflict-oriented problem solving for innovations. The principles of simplification, foolproof design, clarity of states, and tolerance from intrinsic safety were applied to prevent cap loss and minimize the risks associated with ink evaporation. The TRIZ methodology’s contradiction matrix was utilized to identify relevant inventive principles by improving parameters and avoiding worsening parameters, providing a reference basis for product structure design. Lastly, the principles of equitable use, simplicity, intuitiveness, and effortless design from universal design were employed to enhance the marker pen’s usability for the general public. This study creates a SERVQUAL questionnaire to compare the prototype of the designed pen cap with commercially available pen caps. It utilizes the two-dimensional quality model (Kano model) and Importance–Performance Analysis (IPA) for practical design analysis. Finally, the prototype structure is visualized using graphic software. The innovative design features of this study include the following. (1) Concealable pen tip: the sliding seal hides the pen tip inside the pen body when the pen core is slid upwards, preventing cap loss and ink drying. (2) Quick retractable function: using a pressing mechanism, the pen tip can be quickly retracted with a one-handed press and slide motion. (3) Replaceable pen core: the pen core can be replaced by disassembling the pen body, removing the old pen core, and inserting a new one, thereby extending the pen’s lifespan. (4) Satisfaction evaluation of the innovative pen cap design: through questionnaire surveys and cross-analysis using the IPA and the Kano model, this study assesses the product’s manufacturing and mass production value to reduce actual product development costs and time.