The moisture transport at the fuser nip of printers is postulated to be the main reason for paper curls. However, the fundamental mechanisms of paper curling remain unclear. Observing the moisture transport inside a sheet of paper through experiments is difficult because moisture transport rapidly occurs in a micro-scale thickness. Therefore, developing a theoretical model is crucial to understand the mechanisms of paper curling and to control the curls. In this study, we proposed a multiphysics model that includes the moisture and heat transport and mechanical deformation. The elasticity, plasticity, viscosity, and expansion caused by moisture were considered in the mechanical model to describe the complex material characteristics of paper. The curvature of curls was calculated using an effective two-spring model. The mechanisms of curling in printers and the direction of curls were understood through finite element simulations. The proposed model can qualitatively predict the paper curls observed in experiments. The temperature- and moisture-dependent material properties of paper will be studied in the future to improve the proposed model.

打印机的定影压区中的湿气传输被认为是造成纸张卷曲的主要原因。但是，纸张卷曲的基本机理仍不清楚。通过实验观察纸张内部的水分输送是困难的，因为水分输送以微米级的厚度迅速发生。因此，建立一个理论模型对于理解纸张卷曲的机理和控制卷曲至关重要。在这项研究中，我们提出了一个多物理场模型，其中包括水分和热量的传输以及机械变形。在机械模型中考虑了由水分引起的弹性，可塑性，粘度和膨胀，以描述纸张的复杂材料特性。使用有效的两弹簧模型计算卷曲的曲率。通过有限元模拟可以了解打印机中的卷曲机制和卷曲方向。该模型可以定性预测实验中观察到的纸张卷曲。未来将研究与温度和湿度有关的纸张材料特性，以改进所提出的模型。