Convergence Analysis of a Steerable Nip Mechanism for Full Sheet Control in Printing Devices

Abstract

Current approaches for high speed color printers require sheets be accurately positioned as they arrive to the image transfer station (ITS). This goal has been achieved by designing and building a steerable nip mechanism, which is located upstream from the ITS. This mechanism consists of two rollers that not only rotate to advance the paper along the track, but also steer the paper in the yaw direction. This paper briefly reviews the design and experimental setup of the system, and focuses on the design and analysis of a controller that precisely corrects the lateral, longitudinal, and angular positions of the sheet. The control strategy used is based on linearization by state feedback with the addition of internal loops for the local control of the actuators. This paper also provides a methodology to tune the controller parameters so that the desired performance specifications are met. The success of this mechatronic approach is corroborated through simulation and experimental results, which show that the system is able to correct sheet errors and meet all the performance specifications.