TINJAUAN EMULSIFIKASI TINTA OFFSET SERTA PENGEMBANGAN METODE PENGUJIAN DI PT DIC GRAPHICS

Offset printing works on the principle that ink and water do not mix with each other, but instead there are non-image areas on the plate that either accept water (hydrophilic) or reject ink (oleophobic). In the offset printing process there are various ink problems that often arise including tinting/toning, scumming, and over emulsification. Emulsification is the stabilization/mixing of 2 substances that cannot be mixed. In this case, it occurs between the air wetting and the ink in the offset printing process. Ink emulsification may occur due to a lack of balance between water wetting and ink (ink-water balance) while the two materials continuously meet on the plate cylinder during the printing process. Conduct awareness regarding offset ink emulsification and development of test methods to accurately determine the effect of emulsification on the process and print results. Tests were carried out starting with visual data proof and properties testing before emulsion, continued with emulsion testing with variations in the proportion of EC entered, and ended with visual testing of data proof and properties again to see changes in ink before and after emulsification. And obtained that the emulsion can affect the ink.

Cetak offset bekerja berdasarkan prinsip bahwa tinta dan air tidak saling menyatu, melainkan terdapat area non-gambar pada plat yang menerima air (hidrofilik) atau menolak tinta (oleofobik). Pada proses cetak offset tentunya terdapat berbagai permasalahan tinta yang sering timbul diantaranya tinting/toning, scumming, serta over emulsification. Emulsifikasi adalah pemantapan/pencampuran 2 zat yang tidak dapat dicampur. Dalam hal ini terjadi antara air pembasah dan tinta pada proses cetak offset. Emulsifikasi tinta mungkin terjadi dikarenakan kurangnya keseimbangan antara air pembasah dan tinta (ink-water balance) sedangkan kedua bahan tersebut terus menerus bertemu pada silinder plat saat proses cetak. Dilakukan tinjauan terkait emulsifikasi tinta offset serta pengembangan metode pengujian untuk mengetahui pengaruh emulsifikasi terhadap proses dan hasil cetak secara akurat. Pengujian dilakukan dimulai dengan pengujian visual data proof dan properties sebelum emulsifikasi, dilanjutkan pengujian emulsifikasi dengan variasi persentase EC masuk, dan diakhiri dengan pengujian visual data proof serta properties kembali untuk melihat perubahan tinta sebelum dan sesudah emulsifikasi. Dan didapatkan bahwa emulsifikasi dapat mempengaruhi tinta.