Research On The Properties And Printabilities Of Ink Jet Printing Paper With The Optical Recognisable Coatings

Compared with traditional printing processes，the advantages of digital ink-jet printingare more and more obvious, including its low cost，high speed, simple operation, strongconsistency and adaptability. At present, ink-digital printing is favored by many printingcompanies and merchants as a proofing method, and even becomes a printing process of smallbatch production. The quality evaluation system of digital printing has its own characteristicsbecause digital printing is quite different with traditional printing methods.In this study, the evaluation of the proofing quality of the printing papers was carried outfrom four aspects including their tone reproduction of image and color reproduction, thesharpness of image and the uniformity of paper. In experiments, the ESPON STYLUS7600color ink-jet printer was used to make prints, EFI software was used in the basic linearizationof the color ink-jet printing paper, the Spectro-Eye spectrophotometer was used to measurethe color densities, dot gains and L*a*b*values, then relative contrasts and color differences△E were calculated by color difference formula and color Gamuts were drown fromL*a*b*values. A magnifier was used to check the sharpness of text and line by visualcomparison, the uniformities of the different areas of paper were evaluated by calculating thedensities of those of printing areas in the entire paper. The results showed that the commercialink-jet printing sheets measured did not have obvious differences on image sharpness andpaper uniformity, but mainly tone reproduction and color reproduction of image.Then the optical recognition based ink-jet paper coating was developed and studied.Coating composed of multiple porous pigments and vehicle was fabricated on ink-jet printingbase paper made from color fibers so that an excellent printing ink accepted layer was formedon paper and then the paper was semi-transparent. By choosing coating components includingpigment, vehicle, dispersive agent, color fixing agent and coating process reasonably, inkabsorption ability, resolution, print density, and the drying rate of ink drop can be greatlyimproved, color preservation and ink diffusion can be reduced, thus print quality can beimproved. The formulation of coating contained vehicle, pigment and some additives. First,the vehicle of the coating solution was selected and carried out chemical modification toachieve desirable rheological properties for technology requirements. And then the dispersivemethod of nano particles of silica for ink-jet printing paper and the preparation of coatingsolution were discussed. The influences of the dispersive method, the amount and types ofdispersive agents on the viscosity, the distribution of particles and stability of the silica aqueous dispersion were analyzed. Then, the coating solution was coated on the paper basecontaining color fibers. A layer was formed to obtain a new style paper special for ink jetprinting. The print performances of the new style paper were tested. The influences on ink-jetprinting paper and print quality after adding color fixing agent were discussed. The Results ofanalyses showed that the print quality of the obtained coated paper did not have obviousdifference compared with the current commercial products and attained the requirements ofpractical application.Finally, the image optical intensities of the color UV fluorescent fibers before and aftercoating were compared; the results show that the coated layer had no practical impact onoptical recognition of the color fibers.