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うまじよどぎみ
5 years ago
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1 Mechanisms of print gloss development comparison between offset and electrophotography Toshiharu Enomae Graduate School of Agricultural and Life Sciences, the University of Tokyo Yoshihisa Kitano Fuji Xerox Corporation. Abstract Print gloss is one of the important factors influencing print quality and determined by surface smoothness other than refractive indices of the materials formulated in paper and inks. Offset printing where viscous inks transfer to the surfaces of a paper sheet passing printing nips and solidify on the surfaces and electrophotography where solid toner particles are fused and adhere to paper surfaces were compared. Then, mechanisms of the print gloss development were discussed. In offset printing, when an ink split pattern stays on an inked surface of paper immediately past the printing nip, if the ink vehicle is absorbed quickly by the coating, the ink film loses fluidity and the split pattern is left even on the dried inked surface of the paper. This split pattern resulted in a low print gloss. The effects of the formulated amount and chemical structure of latex in coatings, pigment properties, smoothness and porosity of coatings and printing conditions were discussed. For the analysis of electrophotography, surface profiles of paper and printed surface of the identical location were compared in terms of the Pearson s correlation coefficient and the transfer function at every frequency. As a result, roughness at the frequency level, that is, the wavelength level less than the toner particles diameter was found to be eliminated by the electrophotography Thus, offset-like (print gloss changes with paper gloss) electrophotography has been established by controlling toner movement. Keywords: Electrophotography, Ink split pattern, Matte coated paper, Offset printing, Print gloss 1 1)

2 1 2 1 θ=75 I 0 75 I I/I 0 λ θ 2) f(θ, λ) (1) ( ) ( ( )) cosθ n λ sin θ n f θ, n λ = (1) ( ) cosθ + n λ sin θ n ( λ) cosθ n( λ) sin θ ( λ) cosθ + n( λ) sin θ n(λ): λ θ: 75 (2) 3) G s ( θ ) = f v ( θ, n( λ) ) 2 4πσ cosθ exp λ 100 f 0 ( θ, n ( λ) ) glass I: I 0 : σ: ISO JIS (%) % ) (2) , 6) (2)

3 ) 4 5 PET A2 A2 µm 8) mm 9) 10) SB 11) SB 3 12) Ishley 0.55 µm Donigan Ishley 13) µm 14 ) 15, 16 )

4 µm A µm 5 µm 3 µm Gilder 17) 18) SB A2 2 6 m/s Glatter 19) PET ) ( POD) 23) /CTP / /

5 24) / CAP POD 842 POD ) / 1399 / POD 371 / 318 / 48 POD ) Japan Color ml ( DocuColor1250) 4µm 4 ( OK Z OK N )

6 27) , 28) ) (3) Rr 29) Rr = i i ( S1 ( S1 i i S1 S1 ave ave ) 2 ) ( S2 i i ( S2 S2 i ave S2 ) ave ) 2 i S1 S2 S1 ave S2 ave ( Rr 2 n n n 2 Rr 1 A (3)

7 Rr 2 1 Radially Averaged Power Spectrum RAPS 30) (4) Gain ( ) ( ) RAPS Printed surface topography Gain ( db) = 20log (4) RAPS Paper surface topography Gain 0dB 0dB 0dB dB 25(mm -1 ) 0 0dB 150(mm -1 ) ( 6µm(=160(mm -1 ))) 0dB 2 2

8 6 / 31) ), ) JIS Z ) Lee, D. I., "A fundamental study on coating gloss", Tappi Coating Conference Proceedings, 97 (1974). 4) Tappi Test Method T 480 om-92 "Specular gloss of paper and paperboard at 75 degrees". 5) Fetsko, J. M. and Zettlemoyer, A. C., "Factors affecting print gloss and uniformity", Tappi 45(8), 667(1962). 6) Hecklau, F. L. and Pavol, M. Jr., "Gloss and ink holdout properties of coated paper and paperboard as influenced by clay pigmentation", Tappi 50(1), 61A-67A(1967). 7),,, " ( 1 )", 42(2), (2005). 8),,,,,,, " ", 48, 344(1998). 9),,,,,, " ( )",, 53(8), 47-55(1999). 10),,,,,, " 2 ",, G-1(1999). 11),,,,,, " ( )",, 53(8), 47-55(1999). 12),,, " ",, No. 38,

9 21-31(2000). 13) Donigian, D. W., Ishley, J. N. and Wise, K. J., "Coating pore structure and offset printed gloss", Tappi J., 80(5), (1997). 14),,, " ", 63,, 82-87(1996). 15),,, " ", 51(9),79-85 (1997). 16),,, " ", 62,, (1995). 17) Van Gilder, R. L. and Purfeerst, R. D., "Commercial six-color press runnability and the rate of ink-tack build as related to the latex polymer solubility parameter", Tappi J. 77(5), (1994). 18),,,,,, " ", 52(2), (1998). 19) Glatter, T. and Bousfield, D., "Print gloss development on a model substrate", Tappi J. 80(7), (1997). 20), " Color DocuTech 60V / DocuColor 6060 ",, 42, 4, (2003). 21) Y. S. Ng, Aslam, M., Tombs, T., Peter, K., "Kodak NexPress ",, 44, 1, 42-48(2005). 22),, " - -",, 44, 1, 53-59(2005). 23), "POD 2001", 17-22(2001). 24), " ", Printers Circle, 12, 56-58(2004). 25) Corr, C., "The Print On Demand Market Opportunity", CAP VENTURES, ( ),,, " ",, 44, 6, (2005). 27),,,,, Japan Hardcopy'99, (1999). 28), " ",, 89-94(2002). 29),,,, (2004). 30) Ulichney, R., "Digital Halftoning", MIT Press(1988). 31) Kitano, Y. Enomae T. and Isogai A., "Comparative studies of gloss development in electrophotography and offset printing", submitted to Journal of Imaging Science and Technology.

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年次大会原稿最終.PDF

年次大会原稿最終.PDF Structural Analysis of Coating Layer Containing Plastic Pigments Yoko Saito, Hideki Touda, Junji Kasai ZEON Corporation Hitomi Hamada, Toshiharu Enomae, Fumihiko Onabe The University of Tokyo Recently,