Study On The Intelligent Control Technique For Offset Printing

Today, digitize and intelligence is the trend of printing industry, in this paper, offset quality control was systematically researched by the intellectual technologies, including fuzzy logic and neural network control, case expert system and genetic algorithm etc., and the key technologies on the on-line color detection and synchronization control of sheet feeding machine of shaft-less drives (SFMSD) were also conducted with exploratory.On the basis of analysis of production testing and conclusion of the experts'practical experience in printing, the offset quality appraising index system was constructed and the appraising parameters of the index were established in this paper. Furthermore, the process and quality influencing factors of offset printing and the requirements and characteristics of control were completely analyzed.The paper go in detail about the method of analytic hierarchy process (AHP) combined with fuzzy evaluation, which were applied to the comprehensive evaluation of the presswork quality. The basic evaluation theoretical frame of multi-level fuzzy comprehensive for printing quality was established, which provide the assessment and influencing for various indicators of printing quality, so that to make reasonable and scientific evaluation for overall state of the presswork.Based on the analysis of the print-color reproduction quality and its influencing factors, the method of print-color detection by near-infrared spectroscopy was presented to predict the color by designing the data model with partial least-squares (PLS), which laid a good foundation for the on-line print-color detection. The experimental results show that using near-infrared spectroscopy technology and PLS modeling method can measure the print-color very accurately, which create a good condition for on-line print-color detection with near-infrared spectroscopy and optimal control on print process.Combined with the characteristics of transmission system in sheet feeding machine, a hybrid synchronous control algorithm, based on SFMSD, was proposed in this paper, which provides a theoretical basis for the development and technical support of high-speed stability SFMSD, and also provides a good practical basis for widely application of the non-shaft drive technology in the printing industry.According to the characteristics of offset process and quality control, the method of fuzzy neural network control on offset quality was proposed for the first time, which was discussed in detail in the paper. On the basis of this idea, the solution of the key technologies, such as the knowledge expression in system designing, construction of the case-base and the solution strategies of the system, was presented.At last, from the point of engineering practice, an implementation of intelligent control technique for offset quality was put forward, which has directive meaning to practical application.