The effect of refining, forming, and pressing on fine paper quality

The effect of stock refining, forming, and press loading on the properties of fine paper was investigated using a pilot paper machine. It was found that changes in pulp refining and press hip loads have only a small effect on the sheet bulk. Sheet bulk was increased more by unloading the first press than by unloading the fourth press. Higher press nip loads increased the internal bond strength but had only a small effect on tensile, burst, and tear strength. The print quality was enhanced more by increasing the load of the first press than that of the last press. The paper side exposed to the press felt in the last-press nip tended to be rougher, and the roughness increased with nip load. Print quality was improved on the paper side that contacted the felt in the first-press nip. No significant movement of filler in the sheet thickness was observed, even under extreme pressing conditions.