Offset Emulsification and Printing Appropriateness of Offset Printing (I)

The neglect of the emulsification problem is one of the reasons for the low quality of printing in China's newspapers. For example, the problem of matching fountain solution and ink is ignored. Regardless of ink type, the same fountain solution is used. Similar phenomena are extremely common. Therefore, this topic specifically designed for newspaper offset printing, designed and conducted a series of experiments, and hoped to have guiding significance for production.

1 experimental hypothesis

1.1 Factors affecting the ink emulsification rate (1) The action time of the mechanical force;
(2) the proportion of ink and wash;
(3) different inks;
(4) PH value of fountain solution

1.2 Effect of Emulsification Rate on Printability of Ink

The effect on operational fitness: Since ink rheology is one of the decisive factors for ink performance, Tack value is a representative indicator of ink rheology. So use the Tack value to guess the ink's operational suitability.

The impact on the quality of fitness: For newspaper printing, printing density is very important, so use the density of the field as a representative of the quality of ink.

In order to obtain the experimental data of the above indicators, this project has designed and conducted the following experiments:

(1) The effect of stirring time on the emulsification rate of the ink.
(2) The effect of fountain solution supply rate on the emulsification rate of the ink.
(3) The effect of ink emulsification rate on its Tack value.
(4) The effect of the ink emulsification rate on the density of printed solids.
Determination of ink emulsification rate. Use the "approximate gravimetric method". Calculated as follows:




2 laboratory equipment

(1) Ink: Taiyuan TL8021 rotary offset black ink; Shenzhen BeiRi rotary offset black ink.
(2) Fountain solution (3) Alkaline: Taiyuan TL8021 web offset printing black ink supporting fountain solution and water is prepared at 1:80 pH=7-8.
(4) Acidity: Shanghai-produced Long Brand PS wetting powder and water with 1: 1000 pH value: 5-6.
(5) Water: Normal tap water has a pH of approximately 7.
(6) Paper: US-made 49g newsprint.
(7) Balance: Tray drug balance, model HC.TP12A.1.
(8) Printing suitability instrument: Holland 1 GT ATC2-5 printability instrument; printing plate: 5cm wide plastic disk.
(9) Density: Switzerland GRETA GD186 densitometer.
(10) Viscometer: Dutch TACK-O-SCOPE viscosity.
(11) Stirring device: Electric mixer: Model D90-1, Hangzhou Instrument Motor Factory; pressure regulator: Model TDGC-0 .5, Beijing regulator plant; stainless steel stirring rod: diameter 8mm length 200mm, Shenyang City Friends Science Equipment Factory; stainless steel mixing blade: diameter 30mm, Shenyang Youlian Scientific Equipment Factory.
(12) Others: 120# Solvent Gasoline, Squeegee, Refiller, Dropper, Pipette, Plastic Bottle, Watch, Label.

(to be continued)