A Grayscale Dynamic Rip Technology For Large Format Inkjet Printer

The domestic LFIP(Large Format Inkjet Printer) has been widely used at home since 2000, and its picture quality and printing speed are the important factors which should be considered in the competition of products. The RIP software is playing an important role to the performance of LFIP. The main function of the RIP software is to convert images from continuous-tone to halftone or multilevel halftone (multitone). In view of some problems within traditional RIP algorithm and procedure, such as slower speed and lower fidelity of images, this dissertation review the theory of digital halftoning first. On the basis of analyzing the distortion of digital multitoning, we propose a novel scheme called multiscale and dynamic RIP based on the green-noise multitoning which is a kind of AM-FM (Amplitude Modulation-Frequency Modulation) hybrid technique. On one hand, we improve the multi-pass printing mode and utilize the mechanical characteristic of LFIP to form a clustered dot just like the behavior of amplitude modulation to remove the coarse grain in the highlight area of the output on the premise of not reducing printing speed; On the other hand, we apply threshold modulation and information feedforward to multiscale error diffusion to reduce the possibility of the information losing in highlight region and decrease the false contouring of the output. Moreover, dynamic RIP greatly saves the whole printing time by realizing the parallel procedure between RIP and printing. In conclusion, the upgrade of current RIP software could benefit a lot from the multiscale and dynamic RIP technique which improves not only the output image quality but also the conveniency of operation for users. The research and practice of this thesis possesses certain practical significance and referential value for the RIP software development of domestic LFIP.