Problem with streak on blanket SM52

First I wanna thank you all for helping me to try to solve the problem.

And so far I think that I successfully solved the problem.
The problem was in third inker, the stripe on te oscilator roller was only 1,5 mm so I put a little more presssure and now a stripe on the oscilator roller are 5mm ( on all oscilator rollers). I was able to print with out a "mistry line".

After that we had a representative of one leading company in printing cemistry and he proposed that we try his foutan solution and that we will get better print quality with less IPA consumption. But that in the first try was not the case, my water was around 70% and that was unacceptable,so I tryed to reset a dampening roller and I manage to decrease a water to 60%.Then I increased the IPA from 1% to 5%(acording to my araeometer readings) but I think that the real IPA is around 9% and my water is now 40% and my print quality is better then with old one dampening solution. But now on the leading edge of the plate I have a line tick around 1-1,5 mm ,and before that line was tick around 0,5mm. My dampening form roller stripe on the plate is set to 5mm if I decrease that pressure line becomes ticker,and I am afraid that if I put more pressure I will damage the roller.When I put the inker rollers down to plate and after I engage a water roller on the plate,the plate is completly clean in 3-4 revolution.So do I have a "problem" or this is ok set up.

My roller set up is:
1.inker to a plate 4 mm
2.inker to a plate 3mm
3 and 4 inker to a plate 2mm

all inkers to oscilating rollers 5mm

Dampening form roller to a plate 5mm
Dampening form roller to dampener oscillator roller (mat chrome roller) 5mm
Dampening form roller to intermediate roller ( Z roller) 2 mm
Dampening form roller to application roller (chrome roller) I don't know because my line is doubling when I engaging them so I try to set them with a paper stripes.

My first mix of dampening solution was with demineralized water with 3% of buffer and 4% IPA (my first araeometer reading 1%).Water on machine is 70%.

My second mix the successful one so far is mix demineralized water (10 liters) with tap water ( 9 liters) 3% of buffer and 8% IPA ( araeometer reading 5%).
I mix with tap water( we still can drink water from tap) because maybe demineralized water was to soft and maybe because of that I could not manage to print with less water. In my region we have very hard water around 21dH with conductivity around 730 μs/cm and Ph 7 so I think that if I mix them I will get better result. Is this has any sence.

 

Hi, Lines like these are usually a number of factors. Rollers that are clogged up with calcium or the use of anti skin will slip and therefore run at a different speed in the roller train, this causes a water retention in the ink and a release that gradually forms a line across the blanket. The cure for this is to shampoo the rollers and decalcify them to bring back the nap or take them out and clean them by hand with a mild ink stripper, but make sure you neutralise thoroughly. Next you should look at your wash up procedure - water miscible wash up solutions can often leave residue that breaks down the ink to make it change its viscosity (it becomes more runny). Use a wash up program that eliminates the residue and do not use anti skin near the rollers - anti skin is full of surfactants that cause the rollers to become coated like teflon. The stiffer the ink the less this line will appear. e.g. In hot weather or a hot machine will show this line more. Chilled rollers would help, but that is expensive to do. A test for this is to put some ink in a fridge and then put some in the duct when you are ready to run. This will have the immediate effect of reducing or eliminating the line, but it will gradually appear as the ink warms up. Some vegetable based inks are not as stiff as they should be and you will notice that one or two colours in the 4 col set will be better than others. A good idea is to look at the set you are using to try and get a higher strength pigment, (stiffer) set. Roller settings, diameter of rollers and shore hardness are all key to perfect print - poor roller settings will cause water retention in the train, roller slipping and poor washing up. Old rollers with the wrong diameter will cause rollers to run at different speeds and the right shore hardness will allow the correct ink water balance to exist. Basically, renew where you can and buy the best rollers for you machine. Make sure your fount solution is well balanced - It needs to be set up with the right conductivity as well as ph. You can get this done free of charge by your sundries supplier as they have chemist they employ for this work. Hope these things help and sorry if I am telling you things you already know.

 

You may be able to get rid of this by changing the ductor timing and oscillation timing, I did
.