非接觸式熱列印元件之分析與設計

Abstract

本論文研究之主旨為探討利用懸浮微熱元進行非接觸式熱列印之特性分析與設計。這種列印方法可降低熱流失至基板上，因此可提昇列印之熱效率；使用懸浮微熱元可降低元件熱容，並加快列印速度；利用空氣做為熱傳導媒介，可避免傳統接觸式熱列印之抗磨需求。此微熱元可在單晶矽上以微加工技術來製作，並將驅動電路製作在同一晶片上，因此可免除大量的打線作業。本研究以一解析度200dpi的整合性微熱元陣列為例，進行分析評估，同時建立元件熱電模式，並使用SPICE軟體進行熱電動態特性研究。由模擬結果顯示，在1□m的空氣縫隙時，熱能傳送效率可達40%以上，這優於傳統之20%性能，在A4尺寸的列印速度也可高達27ppm。此外，精確的熱參數量測有助於元件的設計分析，本研究也探討兩種熱參數萃取方法：熱敏法與直流法。經由此二種實驗方法，可獲得元件的熱導、熱容甚至熱輻射的吸收率及放射率。這些獲得的參數可做為熱電模擬分析設計的驗證基礎。

A new concept of making contact-less direct thermal printing by using a floating micro-heater is proposed and evaluated in this article. The thermal efficiency and printing speed can be improved due to the floating structure. The wear-resist requirement can also be reduced utilizing air conduction. The micro-heater can be made of single-crystal silicon by micromachining technology, hence the associated driving circuits can be fabricated monolithically with the heater to exempt from the tedious work of numerous wire bonding. An illustrative device of integrated micro-heater array in 200dpi resolution has been evaluated for this new printing application. An electrothermal model of the device has also been set up and studied of its dynamic behaviors using the SPICE package. The simulation indicates that efficiency of more than 40%, better than the conventional performance of 20%, can be achieved with a practical 1□m air gap. The printing speed of 27ppm can be achieved for A4 size printing. In addition, two methods for thermal parameters extraction are also provided here: the bolometric method, and the d.c. electrical method. The thermal conductance, heat capacitance, absorptance, as well as emissivity of a device can be extracted from the experiments. These parameters provide the essential data for the electrothermal simulation and design analysis.