Four colors from two units
Note: this tip comes from the “Ask The Experts” Section of Printers Advantage, an online resource from Heidelberg. For more, please visit www.printersadvantage.com. Q: We have a Printmaster QM 46-2 and have tried on the odd occasion to print four-color process runs, with relatively pleasing results. However, we found a few issues. First, we could only use an A4 sheet size, long edge into the grip. We had to use a 200 gsm board, and the register did move slightly. Is there any more information on what paper weights run the best for four-color work? Do you have to keep the pile pressed fully against the spring or slightly touching to keep a tight register throughout the length of the run?
A: To obtain the best possible results when running four-color process jobs on the Printmaster QM 46, start with good quality paper running long grain: 80- and 100-lb. text weight, minimum. This will help eliminate “fan out” register problems in the tail corners. If you have an IR dryer, use it at approximately 70% on the first pass to prevent paper shrinkage during drying, then at 90-95% on the final pass.
If the job is two-sided, run all four colors on one side before running the back side. Otherwise, you will have fit issues on medium-to-long runs. It is also recommended that the loads be covered with plastic if the second pass of the four-color job will not be run on the same day. This will help keep the moisture in the paper, which helps with fit on the second pass.
When setting up the feeder, always make sure the paper is firmly held to the front and side standards, and test to be sure it will feed consistently before you start the run. Once you have verified that the job is in fit and is registering to your satisfaction, do not change it during the run. This will help to insure consistent register throughout the run.