Miami University

Instrumentation Laboratory Project Page

Project: Paper Wetter Project

Department: Paper Science & Engineering

Primary Investigator: Dr. Douglas Coffin

Purpose: Inks for ink jet printers are water based; paper is hydrophilic. This combination can lead to troubles. As the water enters and leaves the paper, dimensional instabilities such as wrinkles often develop. Ink jet papers typically have coated surfaces or at least surface treatments to combat this problem. Commercial inkjet printers run at high speed and are web-fed processes. That is the paper is not sheeted but comes in a roll. To improve profits, printers do not use special papers and as a result have more problems with wrinkles and paper curl. The manufacturer of these printers would like to guide papermakers in producing base sheets that would have minimum wrinkling. The objective of our project is to determine how base sheet properties affect the wrinkle behavior in ink-jet printing. To accomplish this we needed to create a method to simulate the ink-jet printing process and evaluate the wrinkle propensity of different papers. This was why we developed the "wrinkler". Ink is supplied with a pressurized nozzle that travels above the paper. The IL made a rack and pinon system that is driven by a motor to carry the ink-sprayer across the sheet at a uniform velocity. The speed of the movement can be varied and the motion is started with a trigger. The paper is mounted on a frame mounted to a linear rail. After the ink has been applied the paper is moved to an observation area, where the development of wrinkles is monitored with a video camera and enhanced with a ronchi-ruled plate to create Moire fringes of constant topography. The entire apparatus is mounted on a cart so that we can carry out the simulations in our humidity controlled lab.

Picture of Paper Wetter

IL Comment: Mechanical portions of project were adapted to cart and slide rail provided by user. Rack and pinion system and DC motor with speed control were designed and built by I/L. System provides controllability and reproducibility not possible with the user-built pendulum style prototype.

Cost to researcher: $461.65

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