FN i,D i X Y Z Paper Ink Drop F = Flow Rate N i = Number of pores of diameter D i F Z >> F X,y F Z << F X,y

Pore Size Distribution In the z-direction In the x & y directions Pore distribution requirements of specialty paper LaminateCoated

Flow Porometry P orosimetry Gas adsorption None of these can determine the required porosity

Pores of the sample are spontaneously filled with a wetting liquid (  l/s <  g/s ) Increased differential pressure of gas on one side of the sample is used to remove liquid from pores and permit gas flow to occur (  l/s <  g/s ) Wetting liquid Gas, Differential pressure, p Sample D=4  / p D = pore diameter  = surface tension of liquid p = differential pressure Flow rates through wet and dry samples measured as functions of differential pressure yield all the required properties

Technology of gas flow in z-direction Technology of gas flow in x & y directions

Fully Automated State-of-the-art components Innovative design concepts Highly reproducible data

Variation of flow rate with differential pressure z dir. x-y dir.

The largest and mean pore diameters Direction The largest pore diameter, microns The mean pore diameter, microns Z-direction x & y directions

Pore Size Distribution z dir. x-y dir.

Examples of Pore diameters in z-direction and in x & y directions

Print quality is controlled by pore structure in z-direction as well as x & y directions. These characteristics can not be measured by techniques that are currently available. A novel technology has been described that can measure these properties.

The largest pore diameter, the mean pore diameter and the pore size distribution in the z-direction (thickness of paper) as well as in the x & y directions (in the plane of the paper) of a specialty printing paper have been measured. Similar results obtained with a number of other papers have also been presented. Pore structure in the z-direction is considerably different from that in the x & y directions.

This is the only technique that can measure the pore structures in the plane of the paper as well as along the thickness of the paper.