Using iterative learning control with basis functions to compensate medium deformation in a wide-format inkjet printer

The increase of paper size and production speed in wide-format inkjet printing systems is limited by significant in-plane deformation of the paper during printing. To increase both the production speed and paper size, the compensation of paper deformation is essential. A potential approach to compensate the paper deformation is actively changing the longitudinal paper position during a lateral pass of the printheads. This paper aims at developing an Iterative Learning Control (ILC) algorithm suited for this compensation strategy. The paper position is measured directly, but in non-real-time using image data obtained with a scanner located at the printheads. The proposed controller is experimentally validated and compared with standard norm-optimal ILC in a reproducible experiment, where a set of benchmark trajectories is used that represents severe paper deformation. The results show that in contrast to standard ILC, the ILC with basis functions achieves good tracking performance for the reference set and is hence a proper candidate algorithm for the compensation strategy.