| The market demand for personalized corrugated packaging is gradually increasing,and the quality requirements for corrugated cardboard printing are also increasing.The surface of corrugated cardboard is characterized by rough fibers,loose interlacing and une venness,resulting in serious loss of ink dots and poor color reproduction effect.At the same time,its own background color will also cause serious color cast after ink printing.It is too difficult to reflect the color and level of the original very well.This paper mainly studies the dot gain rule and the color rendering property of corrugated board inkjet printing and corrects the color deviation of corrugated board through G7 correction,TVI correction and Device-Link correction methods.Finally,the random forest algorithm is used to predict the color of corrugated board inkjet printing.The main research contents are as follows:(1)The basic characteristics of different batches of corrugated board and grey based white board were measured through paper characteristics experiment,and the surface properties of the two kinds of boards were compared and analyzed.It was found that the indexes of corrugated board and grey based white board were greatly different.At the same time,the difference of ink-jet printing color effect between corrugated board and gray base white board is analyzed theoretically.(2)Under the same ink-jet printing conditions,gray background white board and corrugated board were printed.The difference of dot quality between the two kinds of paperboard was analyzed from the step reproduction curve and dot gain curve.It can be seen that the gradient of the corrugated board is shorter than that of the gray based white board due to the background color,which can display a small range of colors.The dot gain law of the two board is inconsistent.The reason is analyzed from the perspective of the ink spreading penetration theory and the micro image.The dot gain expression of four-color ink on corrugated board was obtained by polynomial fitting.The correlation coefficient of four-color ink was greater than 0.98,and the fitting was good.(3)Through GATF density evaluation method,the color rendering properties of UV curable ink on corrugated board and gray based white board were studied from four aspects of color intensity,color efficiency,color gray scale and color phase error,and the influence of the background color of corrugated board on the color rendering of ink at different le vels was specifically analyzed.Draw the cardboard-ink GATF color wheel diagram,and visually analyze and compare the difference of color gamut distribution between the two kinds of cardboard.(4)Based on the dot pattern of corrugated board ink-jet printing and the color deviation of the printed image,color correction is conducted for corrugated board ink-jet printing.Three correction methods,G7 correction,TVI correction and Device-Link,are used to correct the color deviation of corrugated board.From the perspective of color restoration,gradation,glossiness and overall picture,which correction method is more suitable for color correction of corrugated board ink-jet printing is comprehensively analyzed.(5)Using the color properties of inks in different tones,inkjet printers print UV light-curable inks on gray manila board,and establish the management and prediction of corrugated board printing colors through random forest algorithm.Based on the cardboard-ink GATF color wheel diagram of corrugated board and gray manila board,the L~*a~*b~*color space relationship model between the two cardboards was established through random forest algorithm and printing ladder color data,which provides an effective reference for the color rendering effect of corrugated board inkjet printing in actual production. |
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