Further Laboratory Studies of Penetration in the Press Nip During the Printing Moment.

An improved apparatus for the measurement of liquid penetration into porous webs during the printing moment at a press nip is described. Changes in the optical system have rendered the observations more amenable to mathematical interpretation, while changes in the electronic components have simplified the analysis of the data so that they can be more readily handled by a computer. Preliminary studies of the mechanism of vehicle penetration during the printing moment would suggest unexpected redistributions of the vehicle on the outgoing side of the nip. Other suggested uses for this apparatus include the study of the penetration of other fluid systems, such as coatings and adhesives, and the investigation of the changes in surface smoothness of webs under the dynamic conditions of a press nip with changing speeds, pressures, nip widths and printing surfaces.