Q I am not a printer, but I work at a printer here in Nigeria (I guess that makes me some sort of printer after all). I have a few questions regarding the print quality of jobs produced in the pressroom; I don't think they are getting it right, even though the machine is a Heidelberg Speedmaster five-colour with CPC. So I have a few questions:
1 What are the causes of colour variation in print?
2 How well will a printing machine work in a ‘not very cold' environment?
3 Why will a press experience breakdown of machines more often?
4 How do I tackle machines, engineers and operator problems?
5 How long is an apprenticeship supposed to last?
6 What is the best age for an operator to man a machine?
I realise this is a lot to ask, but your expertise and advice would be much appreciated.
Sulayman Mustapha, via email
A Well, Sulayman, that is quite a list of queries, and I don't really have the space to go into all your questions in depth here. Having spoken to Gernot Keller, product manager at Heidelberg here in the UK, we are in agreement that each individual answer could be a lecture in its own right. While we're on the subject of lectures, here in the UK a machine printing apprenticeship typically lasts three years. Some possible steps you may wish to consider would be to hire an expert printer, read all available books on print-related troubleshooting (there was a very useful BPIF handbook Troubleshooting for Printers, which you may still be able to get hold of, the Printing Industries of America also sells a Guide to Troubleshooting for the Sheetfed Offset Press, which you can find at bit.ly/aILt7o), or pay an expert instructor or press room manager to come to your factory for a couple of weeks with the aim of providing training and putting in place suitable quality procedures. Gernot has kindly provided some useful pointers regarding some of the issues you raise in your first question, and I've emailed the full text to you. He says: "It has to be differentiated whether the variations being experienced are within one job. If so, is it from sheet to sheet or are these changes experienced slowly during the run? Or is it happening from job to job?" Likewise, high room temperatures and humidity do influence print stability. You can find some useful information on Heidelberg's website, too, its ‘Profi Tip' series includes a PDF covering problems in the pressroom. You can download it here: bit.ly/aRKVcr.
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