There is a lot of misunderstanding about the basics of print science, even with technical printers in areas such as pharma. If you have any specific questions, I'm always happy to given an opinion if you want to email me.
Hi Steve, interesting view of what happens with Gravure ink transfer. I can see your point from a physics point of view. But from an experienced Gravure printer's perspective, there are ways to control this. First "Stage 1" is the most important part of Gravure. Correct doctor blade, blade angle minimizing contact area on cylinder. Also the distance of blade to impression point will depend on the chemistry of the ink. This can be changed by altering the solvent blend to speed up/ or slow down drying rate. This determines what volume the gravure cell holds at the impression point. If you have incorrect drying rate, you will lose volume, through evaporation. the myth is that the ink dries in the cell after impression. The importance of delivering the cell full of ink to the impression is always overlooked. Gravity takes care of the rest with a good ink system. Gravure is a direct contact print process, a thing that Flexography will never match with anilox to plate to substrate. Ink transfer also depends on what cell angle you are using also. You have to match cell angle to the ink film weight you wish to transfer. 30 degrees low ink transfer/ hi def(compressed cell) 60 degree hi volume/solid coverage (elongated). I would be happy to discuss any of these points with you.
Sorry for my slow reply. Yes, in my Printing Science book I point out that spending time on the "trivial" details of setting up the doctor blade is the single most important thing to be done. I'd not thought of the distance from blade to impression point - thanks for pointing it out. I'll update the book to mention this.
sir,
thanks for your post, i ve recently join in a pharma printing industry, your post is very helpful for me to understand process,
There is a lot of misunderstanding about the basics of print science, even with technical printers in areas such as pharma. If you have any specific questions, I'm always happy to given an opinion if you want to email me.
Steven Abbott tq for info
Sir any pdf on heidelberg 5,6,7 color machine
Hi Steve, interesting view of what happens with Gravure ink transfer. I can see your point from a physics point of view. But from an experienced Gravure printer's perspective, there are ways to control this. First "Stage 1" is the most important part of Gravure. Correct doctor blade, blade angle minimizing contact area on cylinder. Also the distance of blade to impression point will depend on the chemistry of the ink. This can be changed by altering the solvent blend to speed up/ or slow down drying rate. This determines what volume the gravure cell holds at the impression point. If you have incorrect drying rate, you will lose volume, through evaporation. the myth is that the ink dries in the cell after impression. The importance of delivering the cell full of ink to the impression is always overlooked. Gravity takes care of the rest with a good ink system. Gravure is a direct contact print process, a thing that Flexography will never match with anilox to plate to substrate. Ink transfer also depends on what cell angle you are using also. You have to match cell angle to the ink film weight you wish to transfer. 30 degrees low ink transfer/ hi def(compressed cell) 60 degree hi volume/solid coverage (elongated).
I would be happy to discuss any of these points with you.
Sorry for my slow reply. Yes, in my Printing Science book I point out that spending time on the "trivial" details of setting up the doctor blade is the single most important thing to be done. I'd not thought of the distance from blade to impression point - thanks for pointing it out. I'll update the book to mention this.
excelent video....