Vibrations of offset printing presses are serious problem, which cause many difficulties while printing and impair quality of the prints. The biggest problem lies in construction of printing unit. It mainly consists o...Vibrations of offset printing presses are serious problem, which cause many difficulties while printing and impair quality of the prints. The biggest problem lies in construction of printing unit. It mainly consists of three cylinders, but two of them are in a direct contact generate undesired vibrations. Construction of the cylinders makes that stiffness of the unit varies periodically while printing. In this paper model of offset printing unit is presented. The model is described by the system of two parametric differential equations. Computer simulations of the behaviour of the printing unit have been performed. Conditions in which parametric resonance appears are also appointed here.展开更多
In the inking system of an offset printing press,a vibrator roller distributes ink not only in the circumferential direction but also in the axial direction.In the control process,if ink amount is determined only by t...In the inking system of an offset printing press,a vibrator roller distributes ink not only in the circumferential direction but also in the axial direction.In the control process,if ink amount is determined only by the dot area coverage without considering the impact of vibrator roller's oscillation,the printing colour quality will be reduced.This paper describes a method of calculating the impact factor of vibrator roller' s oscillation.First,the oscillation performance is analyzed and sample data of impact factor is got.Then,a fuzzy controller used for the calculation of the impact factor is designed,and genetic algorithm is used to optimize membership functions and obtain the fuzzy control rules automatically.This fuzzy controller can be used to calculate impact factors for any printing condition,and the impact factors can be used for ink amount control in printing process and it is important for higher printing colour quality and lowering ink and paper waste.展开更多
文摘Vibrations of offset printing presses are serious problem, which cause many difficulties while printing and impair quality of the prints. The biggest problem lies in construction of printing unit. It mainly consists of three cylinders, but two of them are in a direct contact generate undesired vibrations. Construction of the cylinders makes that stiffness of the unit varies periodically while printing. In this paper model of offset printing unit is presented. The model is described by the system of two parametric differential equations. Computer simulations of the behaviour of the printing unit have been performed. Conditions in which parametric resonance appears are also appointed here.
基金Supported by the National Science and Technology Supporting Program(No.2012BAF13B05-1)National Natural Science Foundation(No.51105009)Beijing Natural Science Foundation(No.3113025)
文摘In the inking system of an offset printing press,a vibrator roller distributes ink not only in the circumferential direction but also in the axial direction.In the control process,if ink amount is determined only by the dot area coverage without considering the impact of vibrator roller's oscillation,the printing colour quality will be reduced.This paper describes a method of calculating the impact factor of vibrator roller' s oscillation.First,the oscillation performance is analyzed and sample data of impact factor is got.Then,a fuzzy controller used for the calculation of the impact factor is designed,and genetic algorithm is used to optimize membership functions and obtain the fuzzy control rules automatically.This fuzzy controller can be used to calculate impact factors for any printing condition,and the impact factors can be used for ink amount control in printing process and it is important for higher printing colour quality and lowering ink and paper waste.
