Verification of Cockling Reduction Effect on Offset-coated Paper by Drying Technology Using Laser Exposure and Consideration on Cockling Mechanism by FEM Simulation Modified Thermal Expansion Model

Abstract

Fuji Xerox has been developing high-speed inkjet continuous feed printing system for commercial printing market. Offset coated paper used there has relatively low permeability, which causes poor fixing performance and paper cockling in high print coverage. We have researched laser-drying technology with high energy density as a new drying system. This system can quickly heat only the ink without heating any moisture component in paper due to having peaky near-infrared wavelength. In this study, we demonstrate the laser-drying technology can restrain cockling in offset-coated papers (128gsm and 73gsm) using VCSEL as a laser system. Furthermore we develop cockling simulation model based on bi-metal model considering water swelling in printed area and anisotropy of paper fiber orientation. The influences of water swelling ratio and ink penetration depth on cockling profile are investigated and the conditions reproducing experimental results are also demonstrated in the case of with/without laser exposure.