Study of Ink Transfer Mechanism -Pinhole Formation on the Printed Surface-

Abstract

In the ink trapping using a cast-coated paper with black inks for offset proofing and synthetic paper, we detected many pinholes on printed surface. The numbers of the pinholes (N_pinhole) increased according to lapse of time after the trapping during initial 6 hrs. These N_pinhole values at 24 hrs decreased with increasing amount of transferred ink (y). The N_pinhole value of the printed matter with web offset ink at 24 hrs was independent of the y value. Using poly (ethyleneterephthalate) (PET) film, there are many pinholes on the surface. Clarifing ink transfer mechanism, the pinhole formations were studied by means of y-N_pinhole reactions, time-profiles of the N_pinhole value, effects of drying temperature, and drying atmosphere and so on.