Pressroom temperature for Alcolor?

[5150pressman]

After you have set the rollers and start running. Check and see if the oscillators are picking up ink. Its not suppose to. Try using some chrome roller cleaner on it if it does.
Good luck.

 

[turbotom1052]

water problems

ive found that if all roller settings and fountain solution is correct that uneven water film on the plate is usually caused by a buildup of calcium carbonate in the ink rollers. try giving the problem printing unit a thorough cleaning with a commercially available alkaline rinse solution. id do it a number of times to be sure all traces of calcium carbonate have been been removed from ink train, then get on a regular schedule of alkaline rinses to be determined by the types of stocks you run. once a week alakaline rinses will go a long way in keeping your ink train in tip top shape. good luck in finding a workable solution
tom

 

[m_alatorre]

Hi,

I was using alcohol between 8 and 10 and somebobdy told me to try between 15 and 20. I did and the problem seemed to go away.... I don't know yet but it looks like the problem is gone.

I jost hope it doesn't come back next week.

Thanks to all

P.D. I checked the oscilators and they don't pick up ink

 

[turbotom1052]

running all that alcohol

running alcohol in excess of 5 % in a modern sheetfed enviroment is absurd. alcholol is nothing more that a band aid to hide a problem elsewhere. alcohol does the same thing on an offset press as it does in the human body. it smoothes out the rough edges. if you need to use more than 5% alcholol your dependant. just say no to alcohol and enjoy the obvious enviromental benefits along with more vibrant colors with less ink

 

[m_alatorre]

Does some other Alcolor GTO operator needs to use 15-18% of alcohol to avoid problems? Specially... Someone using mexican alcohol?(for it might be different from the one sold in other parts of the world)
Machine is working fine with that much but i seem to need a lot of ink to keep the density where i want it. If i use ANY less alcohol machine will go crazy and start scumming on one edge of the plate and putting a lot of water on the other. The guy who told me to run that much alcohol is a heidelberg tech (here in MX)and said that's how it's done here(Don't know if by "here" he ment "Mexico" or "Alcolor GTO's")

Just want to see if i got some where or i should keep looking.

Thanks

 

[luke]

15% -20% IPA,, you are kidding me right
anyone recomending that and any operator running with that much alcohol should seriously think twice..
Think of the health risks you are putting yourself through as well as the other employee's. not to mention the environmental issues..
IPA between 6%-10% is frowned on these days...

How do you achive density? IPA is a solvent and your got a tonn of it in your fount.

What temp are you keeping the fount at.? Don't forget that that the water/fount at a certain temp, can only keep a certain amount of IPA before the IPA will redily evaporate into the air..
(for example running your chiller at 10 deg C. with 10% IPA you would have similar IPA redily evaporating then if you run the chiller at 6 deg c and had 12%-13% IPA) now obviously you can't run it much under 10 deg C as you will have condensation and water dripping all through the machine..

with a good reduced IPA fount there is no reason why you can't run 6% IPA even on polyester plates, but if your on metel plates it should be easy. but if your struggling at 8%-10% then there is a mechanical issue with the machine. be it roller's out of setting, or simply worn rollers..(shore hardness too hard or uneven across the length of the roller.


Now have you checked your roller setting's? and checked bead lines to the plate?
If so is that bead line even all the way across or is it thicker/thinner at the last inch or so on both ends of the water form?

I don't know that dampening system, but doe's the metering roller have the possibility to be scewed, to allow more fount on the ends.. or doe's it have a crown in the middle allowing for more fount on the edge's?

If you can scew it, then do so. this will help fix the scumming up on the ends..
If it is just ment to have a crown in the middle of the roller, check to see if it is worn..

What fount solution are you using?
Mexican alcohol, what the hell is that -tequilla- what doe's your MSDS say, is it isopropanol alcohol or n-propyl alcohol,
Also it should be above 98% pure other wise your problems start from there also...

 

[m_alatorre]

I know using 18% IPA sounds crazy. i've been in offset printing for 15 years now(mostly AB dick) and the last 6 years with heidelberg GTO and SOMRZ. But those are conventional damps and this is my first time with alcolor that's why everyting i'm told(about IPA usage) sound fine with me. I started using 5% but everything i try to print before i get to 17% gets messed up. I ink the plate and then the water form and it cleans but then starts needing more water at certain part of the plate(usually 1 or 2 inches from plate's edge) and, when i increase the water amount(with potentiometer in delivery panel) , it cleans but the rest of the image gets too much water. I've checked roller settings like 10 times and they seem to be right(Calibrate alcolor unit acording to manual) It just doesn't make sense.... I should say we just bught and installed (6 months ago)this GTOZ and hasn't printed anything without using 17% IPA with success. Ink form rollers and water form are new in unit 1 and unit 2 are average, but both units fail the same. I might be making a very simple/stupid mistake in setting up something.... BUT DON'T KNOW WHAT! I'm using Anchor 2912 fount solution(which is buffered) and the alcohol could be less than 98% pure, but i've tried from diferent supplier and seems the same. Pan rollers pick up more water at edges and when you see them running, they seem to transfer a even film of water, so my guess those are fine(but what do i know) Any ideas are wellcome and thanks for the time spent reading.... Moe P.D. If anyone would be willing to share one idea or two over the phone, please just leave a number and i can call worldwide(and almost for free) with skype

 

[Lee Thompson]

what fount additive are you using? here in the UK we use HEIDELBERG recommended addiitive and we are down to 2% alcohol.

 

[6colorpressman]

also condensation might be building up underneath the water pan.....and dripping down.........try to insulate the water pan

 

[lildaddy50]

Ideal pressroom conditions are 72 degrees at 45 percent humidity. Your water temp. should be 55-60 degrees in the roller pan . Do not set water form to plate using a water stripe! All setting must be done when clean and dry. Ink up each end of water rollers using a small hand held roller aprox. 2-3 inches wide. Then drop your damps and check all stripes. Remember, the wider your stripe , the LESS water. It sounds like your stripe to plate at 2.5 mil. is way to narrow. Try a stripe on water form to plate of 5 mil. and 4 mil. on everything else. Including ink forms to plate. Tell your pressman to look at the plate (in the glare) when the press is running. If the plate is shiny ,he is running way to much water. Plate should look powder dry in the glare of overhead lights.

Tell yor pressman to lower water setting until press starts to scum , then go back up just enough to eliminate scum. This will be your min. water setting. Write the min water settinf for each unit on a piece of paper and start there every morning. During the course of a warm day you will have to go up on the water but always start the day at you "min. water settings".

If your in cold weather , the rollers will shrink from the cold over night. You may need to go even below your "min. water settings" early in the morn. You can help this by heating up the pressroom an hour before print work starts. (it takes a long time to change the temp. of all that cold steel). You can also start your press and put it on a fast wash up speed for about 10-15 min. this will warm up all the rubber rollers.


Rod

 

[m_alatorre]

Thank you every one. I realized that i was calibrating water unit without lowering damp roller to plate and that caused Z roller to disconect from both water/ink form rollers when printing and therefore unevenly applying water and the consequent problems. Now we're working with 2 to 3% IPA. Now i'm trying to figure out why i get too much water on plate edges even with new water form roller. Any ideas?

Thamks again
Moe

 

[lildaddy50]

check the meter roller and the pan roller on the outside face on each end of the roller by the bearing. Somethimes they get built up with gum and crap. If your pan roller is chrome, then just use a razer blade to scrape off any crap that may be causing a slinging probem.

Also, are you sure your warer form to plate setting is wide enough. Remember, the wider the stripe, the less water. Try a stripe of about 6-7 mil.

Rod

 

[6colorchuck]

I've read in the manual for Royse tanks that the optimal temperature is 57 degrees f. This is the temperarure at which alcohol evaporates at its most efficient.

 

[6colorchuck]

I fhte macine you operate is a heidelberg MO, try tightening up the meter roller on each side. While printing, snug up one side first untill you start drying up on the end. then open it a little, and do the same for the other side. you may have to run your water feed up a little more. The meter rollers on the MO are crowned, so that is why this works.

 

[6colorchuck]

water temp should be 57 degrees f. this is optimal temperature for minimal aclohol evaporation.