International Paper Company

William R Shields

Kapil Mohan Singh

Frederick P Karsa

James F Suska

Jody MacDonald

Ronald A Stone

The invention provides an apparatus and method for testing the tendency of a paper to curl. The paper is cut from a paper making machine and rapidly humidified to standard TAPPI conditions, and is thereafter run through an apparatus having a substantially vertically oriented nip. The paper is measured for curl, all data are tabulated and fed back into a data acquisition or paper machine control system.

Test to measure curling tendency of paper in laser printers

A paper web formation measurement system provides on-line measurement and control of visual properties of a moving web of paper. The measurement system includes an image acquisition system for capturing images of the moving web, and an image analysis system for analyzing captured images. The image acquisition system includes a strobe lighting system for backlighting the moving web and a charge injection device (CID) camera for capturing light transmitted through the web to form an image of the web in non-standard (non-RS-170), full frame format. Captured images are digitized by the image analysis system to 256 graylevel and analyzed to produce a mathematical formation index representing visual properties of the web. The mathematical formation index, which is derived from a graylevel distribution histogram, is presented to paper production personnel to enable on-line adjustment of process variables to maximize paper quality. The image analysis system is also configured to ascertain the distribution of flocs and voids within the image. The mathematical formation index may be adjusted to reflect the distribution of flocs and voids within the web.

Measurement of visual characteristics of paper

A system for determining characteristics of objects in wood pulp includes a pulp sampling and dilution system for diluting and dispersing samples of pulp, and an imaging/analysis system for capturing images of pulp objects, including fibers, and analyzing the captured images. Samples of pulp are provided to a dispersion tank where pulp is dispersed within a liquid to form a wood pulp slurry having a consistency in the range of from about 0.01 to about 0.001 percent. The dispersed pulp is conducted to a transparent flow cell for imaging and analysis of pulp objects. Light radiating from a light source is reflected off surfaces of objects within the dispersed pulp, producing scattered light. One or more cameras capture scattered light from objects as the objects pass through a camera's field of view. The output of the cameras are digitized and filtered to eliminate motion blur, and the filtered visual image displayed on a monitor. Each pixel of the image is compared to a graylevel threshold, and pixels meeting the graylevel threshold are converted to objects. Object pixels are averaged and compared to a critical mean graylevel threshold. If the average does not meet the critical mean, the object is eliminated from further analysis. Objects meeting the critical mean are analyzed using various size and shape filters to determine properties of the objects. The measured object properties are then displayed on the computer monitor with operator selectable parameters as well as stored in archival files and spreadsheet files, and periodically reviewed by machine operators to enable proper adjustment of process variables.

Growing community of inventors

Newburgh, NY, United States of America

William R Shields