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Bibliographic record number: 392512

Journal

Authors: Cigula, Tomislav; Mahović Poljaček, Sanja; Gojo, Miroslav
Title: New Methods in Contact Angle Measurement
Source: Tiskarstvo 08 / Žiljak, Vilko (ed). - Zagreb : FS, FotoSoft, DAM-KAJ , 2008. 12-12.
Meeting: Tiskarstvo 08
Location and date: Stubičke Toplice, 31.01. - 02.02. 2008.
Keywords: contact angle; goniometer; offset printing; fountain solution
Abstract:
Contact angle is a measure which describes the dampening (interaction between solid and fluid surface) of the solid surface. It is defined as an angle between solid surface and tangent on a fluid drop at point of the three-phase line, where the solid, the liquid and the vapour phase meet. That process is essential in offset printing, while nonprinting areas must be completely covered with the smallest possible amount of fountain solution. Increased dampening quality is established with certain additives in fountain solution which cause the lowering of the fluid surface tension and consequently, reducing of the contact angle values. Dampening of the nonprinting areas will be better if the values of the contact angle are smaller. Older instruments for contact angle measuring were similar to optical microscope. It consists of two movable treads built into one lens. During the measuring process one of the treads has to be adjusted into the parallel position with the solid surface, and the other one as a tangent on a drop of a fluid. Measuring results with this kind of instruments are often inaccurate because are influenced by a operating human. Units like Dataphysics’ OCA30 are computer controlled systems for contact angle measurement. They use a digital camera to make a photo or a film of enlarged area where fluid drop makes her contact with solid surface. The measurement results are computer processed through mathematical simulation to determine value of contact angle. These kind of instruments are giving results with greater precision, enable measuring in defined time (contact angle lower its value in time), it can measure surface tension values as well as surface energy of solids. This kind of instrument enables more accurate measurements in amount of additives in fountain solution what leads to reducing cost of production without lowering print quality.
Type of meeting: Predavanje
Type of presentation in a journal: Abstract
Type of peer-review: No peer-review
Project / theme: 128-1281957-1958, 128-1201785-2228
Original language: ENG
Category: Expert
Research fields:
Graphic technology
Contrib. to CROSBI by: mgojo@grf.hr (mgojo@grf.hr), 19. Svi. 2009. u 11:21 sati



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