ABSTRACT DEVELOPMENT OF A METHOD TO EVALUATE WRINKLING TENDENCY OF INK-JET PAPERS by Brahmananda Reddy Mulaka This thesis presents the development of an apparatus and method to characterize the propensity of papers to form wrinkles in commercial ink-jet printing. An apparatus was developed to apply ink to the paper and then capture the dynamic features of wrinkle development using Shadow Moiré fringe technique and quantify the severity of wrinkling. The developed techniques enable the study of structural and manufacturing variables of the ink-jet papers that affect the severity of wrinkling. A parametric study was carried out to evaluate the influence of specimen dimensions, width of inked region, and tensile load on wrinkling severity. From the fringe images, a set of wrinkle parameters were determined. Finally, twelve different commercial ink-jet papers were studied using the test conditions determined from the parametric study. The proposed method provides a reasonable laboratory technique to evaluate wrinkle tendency of papers. DEVELOPMENT OF A METHOD TO EVALUATE WRINKLING TENDENCY OF INK-JET PAPERS A thesis Submitted to the Faculty of Miami University in partial fulfillment of the degree requirements for the degree of Master of Science Department of Paper Science and Engineering by Brahmananda Reddy Mulaka Miami University Oxford, Ohio 2005 Advisor ___________________________ Dr. Douglas W. Coffin Reader ___________________________ Dr. Robert C. Peterson Reader ___________________________ Dr. Martin D. Sikora TABLE OF CONTENTS 1 INTRODUCTION ................................................................................................................................1 2 THEORETICAL BACKGROUND ....................................................................................................5 2.1 INK-JET PRINTING ...................................................................................................................5 2.2 PAPER-INK INTERACTIONS ....................................................................................................10 2.3 THEORY BEHIND WRINKLE FORMATION ................................................................................12 2.3.1 Definition of Wrinkles......................................................................................................13 2.3.2 Wetting of paper during the ink application:...................................................................13 2.3.3 Desorption during drying ................................................................................................15 2.3.4 Irreversibility of Hygroexpansive strain..........................................................................15 2.3.5 Equilibrium state of the printed sheet..............................................................................17 2.4 WRINKLE DEVELOPMENT DURING WETTING AND DRYING PHASES ........................................17 2.5 SURFACE TOPOGRAPHY BY INTERFEROMETRY ......................................................................19 3 PROJECT DEFINITION AND OBJECTIVES...............................................................................25 4 EXPERIMENTAL METHODS ........................................................................................................26 4.1 METHOD FOR EVALUATING WRINKLES.................................................................................26 4.2 DEVELOPMENT OF INK-JET WRINKLE ANALYZER .................................................................28 4.2.1 Ink Application system.....................................................................................................28 4.2.1.1 The Development pathway .................................................................................................. 32 4.2.2 Paper Holder mechanism ................................................................................................43 4.2.2.1 The Development Pathway .................................................................................................. 46 4.2.3 Load and Heat Application..............................................................................................49 4.2.4 Shadow Moiré Station......................................................................................................50 4.2.4.1 The Development Pathway .................................................................................................. 52 5 PARAMETRIC EVALUATION.......................................................................................................60 5.1 OVERVIEW OF THE EXPERIMENT ...........................................................................................60 5.1.1 Sample Preparation .........................................................................................................60 5.1.2 Preparation of the apparatus...........................................................................................61 5.1.3 Running a test ..................................................................................................................62 5.2 EVALUATION OF TESTING PARAMETERS ................................................................................63 5.3 RESULTS AND DISCUSSION....................................................................................................63 5.3.1 Quantification of the Ink Application ..............................................................................63 5.3.2 Image analysis .................................................................................................................67 5.3.3 Data Analysis...................................................................................................................69 5.3.3.1 Wet Image............................................................................................................................ 70 5.3.3.2 Dry Image ............................................................................................................................ 71 5.3.4 Effect of the Variables......................................................................................................76 5.3.4.1 Effect of Ink width............................................................................................................... 76 5.3.4.2 Effect of Sample dimensions ............................................................................................... 80 5.3.4.3 Effect of MD Tension on the paper...................................................................................... 87 5.3.4.4 Effect of Temperature:......................................................................................................... 92 6 EVALUATION OF INK-JET PAPERS ...........................................................................................95 ii 6.1 RANK BASED ANALYSIS.......................................................................................................100 6.2 COMPARISON WITH COORDINATE MEASUREMENT RESULTS ................................................110 6.3 GENERAL OBSERVATIONS ...................................................................................................114 7 CONCLUSIONS AND RECOMMENDATIONS..........................................................................119 8 REFERENCES .................................................................................................................................122 9 APPENDICES...................................................................................................................................128 APPENDIX A..............................................................................................................................129 APPENDIX B..............................................................................................................................132 APPENDIX C..............................................................................................................................133 APPENDIX D .............................................................................................................................134 APPENDIX E..............................................................................................................................135 APPENDIX F..............................................................................................................................141 iii LIST OF FIGURES Figure 1. Ink-Jet Printing Technology map.........................................................................6 Figure 2. Drop on Demand Ink-Jet Printing. a) Drop formation in a thermal bubble jet b) Drop formation in a piezoelectric ink-jet............................................................7 Figure 3. Typical depiction of a continuous ink-jet printing system...................................9 Figure 4. Different types of wrinkles formed in the Paper under different conditions a) Wrinkles: Non-Uniform wetting/Drying of the sheet. b) Wrinkles: Wetting on one edge of the paper. c) Cockle: Non-Uniform sheet properties. d) Curl: Two- Sidedness. ..............................................................................................................11 Figure 5. Irreversibility of hygroexpansive strain. a) Loss in the hygroexpansive strain in a restraint dried sheet and b) hygroexpansive strain in a freely dried sheet [16]. ..............................................................................................................16 Figure 6. Forces due to non uniform expansion and