Computer Simulation for the Cavitation Changes at the Exit of Offset Printing Nip

Abstract

Offset paper printing is a promising roll-to-roll technique for color printed materials. Although it is no doubt that understanding ink transfer mechanism in offset printing process is necessary to achieve high printing quality, investing the relationship between inks and substrates at the nip is difficult experimentally due to high printing speed. In this paper, rheological behavior and splitting point of the ink at the nip is studied using package software Ployflow and Flow 3D based on Navier-Stokes equation. Polydimethylsiloxane (PDMS) ink and IGT printability tester were used for an model ink and experiment to compare with that of simulation data, respectively. As a result, higher viscosity at state flow and pressure increased ink transfer due to higher possibility of presence of cavitation at the nip and increase in covering area ratio. These results have shown good agreements with experimental data compared by measuring density of print through.

Identification of Mulberry Bast Fiber Using a Multivariate Analysis Technique

“…3,4) 따라서 닥나무 섬유 로 초지한 한지는 물리적 강도 특성과 내구성을 지녀 보 존성이 우수하다. 5,6) 전통한지로 제작된 기록 유산의 우 수한 장기 보존 특성 역시 문헌을 통해 검증된 바 있다. 7) 전통한지는 닥나무를 이용하여 우리나라 고유의 초지방 식으로 제조된 종이를 일컫는데 이는 원재료, 초지방법, 도침의 유무, 생산지 등에 따라 다양하게 불리기도 한다.…”