STUDIES ON IMPROVEMENT IN PRINTABILITY CHARACTERISTICS OF WRITING/PRINTING PAPER BY REDUCING FLUFF CONTENT IN PAPER

Abstract

The printing industry is in a stage of transformation recognizing these differences. Printing operation is becoming progressively faster and more sophisticated. Printers are today demanding tighter specifications on paper uniformity and integrity. Printers also look for the performance of their sophisticated printing machine with respect to functional requirement in paper, such as creasing during printing, high fluff content etc. other than basic requirement i.e. of shade, smoothness, size etc. Fluff in paper creates fluff deposition in the blanket of the printing machine. This results in poor printing machine runnability, production loss, increased ink consumption and reduction in the print impression per hours. In this regard, we perform the study on the generation, characteristics of fluff, and its impact on print quality during printing. Lab study, plant trial and printing trial at printers end were also carried out. Microscopic examination of fluff indicates that it contains the fiber and fines of the length 0.4 to 2.0 mm (average 0.8 mm). Fluff content in paper (by L&W fluff tester) is average 0.844 mg/m2 on topside and 234 nos.sq inches/5 sheets by testing Para type fluff tester. To control the fluff content lab trial was taken with the chemical-1 (Cationic fatty acid condensate product) in wet end and chemical —2 (cross linking chemical poly hydroxylated) at size press. In lab study hand sheets were made by the addition chemical-1 of 2.0 kg/MT in wet-end and hand sheets were coated with the K-coater with the addition of 5.0kg/MT size press chemical-2 in starch. Surface property improved i.e. wax pick from 13A to 14A. To validate the lab study, plant trial of both the chemicals were taken. Chemical-1 was 1.5 kg/MT of paper in mixing chest and Chemcial-2 was added 3.0 kg/MT of paper at size press in the starch solution. This has resulted reduction in fluff generation by 50% and fluff content in paper reduced 0.844 to 0.340 mg/r2 (by L&W fluff tester). Printing trial was taken at leading printer Ajanta Offset. There are improved the print quality and printability characteristics of paper i.e. 7500 to 12000 impression per hours.