|Printing on paper cups|
Originally paper cups were printed using rubber blocks mounted on cylinders, with a different cylinder for each colour. Registration across different colours was very difficult, but later flexography plates became available and with the use of mounting systems it became easier to register across the colours, allowing for more complex designs. Printing flexographic has become ideal for long runs and manufacturers generally use this method when producing over a million cups. Machines such as Comexi are used for this, which have been adapted to take the extra large reels that are required by paper cup manufacturers.
Ink technology has also changed and where solvent-based inks were being used, water-based inks are instead being utilised. One of the side effects of solvent-based inks is that hot drink cups in particular can smell of solvent, whereas water-based inks have eliminated this problem. Other methods of printing have been used for short runs such as offset printing, which can vary from anything from 10,000 to 100,000 cups. Offset printing inks have also been developed and although in the past these were solvent based, the latest soya-based inks have reduced the danger of cups smelling. The latest development is Direct-printing, which allows printing on very small quantities, typically from 1,000 cups, and is used by companies including Brendos ltd offering small quantities in short lead times.
Rotogravure can also be used, but this is extremely expensive and is normally only utilised for items requiring extremely high quality printing like ice cream containers.