color sequence on quickmaster

I have just started running a Heidelberg quickmaster two color duplicator, and although I have looked through every manual, I cannot find any info on the right color sequence for this press. Darker color on the main unit, and lighter color on the # 2 unit or vice versa. I was told that the main unit goes on impression first, and to run darker in that unit, but the guy that has been running it has been doing the opposite. I tried it his way, and my 032 red in the main unit wanted to contaminate with the black in the #2 unit. Anyway common impression blanket. Please help Quickmaster guys!

 

Colour sequence

Hi,

We have had our QM46-2 for 6 months now and we are very happy with it, we can even do the odd 4 col job on it! You must run the lightest colour on PU1 and the darker on PU2 to avoid contamination, we have had runs of 10,000+ with no contamination.

Matt.

 

color sequence

i don't know especially this machine but in general terms, you should print first the darker color then the lighter. After all you tried lighter then darker and you failed. But if you do it the way I suggest, the lighter ink contaminates the darker so you have really no trouble. Althought you should not have any contamination at all, well it's a matter of tolerance.

 

Rotation of the blanket cylinder

The Blanket cylinder hits PU1 first taking the lightest colour ink first, then it rotates round to PU2 taking the darker colour ink; this in turn off sets to the paper; the blanket is then relatively clear and so the process begins again; so lightest in PU1 darkest in PU2

 

well ste then -I didnt know the blanket was common to the 2 printing units. Light first, dark then

 

the darker color should be run first in most situations. in order to prevent contamination of the 2nd down color you need to be sure that the second down color has an adequate ink film thickness in order to preven contamination. ink film thickness has a direct relation to the inks tack. thinner ink films of the same ink will always have more tack than a thicker ink film

 

also dont confuse ink tack with ink body

 

yup, dark ink on unit 2 lighter ink on unit 1, I would think registration would be your biggest problem with a QM