Ink Stripping on ink duct roller

Anyone got any ideas on what could be causing ink stripping on the ink duct rollers on the ends .

The cyan and magenta are the worst affected , at some stages the cyan is stripped clean .

The press is a 2006 cd 74 we mainly run paper of 640mm in width so there is no image area to be inked where the rollers are stripping but i am curious as to the cause , i also have to open the ink keys a hell of a lot to get good color density when there is very little image to be inked ,and if i stop and start again the color is way up .

Any ideas on the cause and any remidies would be very much appreciated.

Cheers all

Dave

 

C c c

I would think you have calcium deposits on your that take the water all the way up.
This will be well noticed on the cyan & magenta first as they have more Calcium in them
Use calcium-FIX from Bottcher - it will solve your problem (i have no share with them - simply the best

 

i agree with meny problem and solloution

 

have you noticed it happening more when you run a smaller sheet? A cd74 maxes out at about 29 inches. if you're running a 25 inch sheet when it's happening then you've got 2 inches on each side where there is no sheet to absorb the excess water. it has to go somewhere so it travels up into your ink fountain unless something is done to keep it in check. This is where the air curtain above the dampening system comes in. If your air curtain is set up and you know it to be working then i agree with the others that claim a calcium problem. their solution should make a difference

 

I had this on a SM 102, I solved it by turning off the chilling to the ductor

 

if the Ink temp control is set to a right temp . i.e. about 28-30 deg c' , this should be the reason.
yet if it is set to freez the ink.... like some people set it to 15 deg ' you are right as this will bring more emulsification and brake more of the ink - to Calsium

 

Could be chiller setting although sounds like you are running far to much water and getting emulsification. Depending on your print order, it could be the damp on theunits before the cyan causing the trouble. Plus step down your ink profile rather than closing the none inked area off altogether.

 

AM KEEN TO BUY A 4 COLOR OFFSET MACHINE IN PUNE,INDIA.Know any interested dealers?

 

yes i do

contact midseapresses@gmail.com
tell them what you need and they will help you

 

Dave Ross
There are a few things that can cause stripping of ink. Too much water not not ink, a cooked roller in the ink train is a common problem, an old water pan rollers that has low spots will do it. Are you running alcohol? If so maybe you have a bunch of hard rollers(I stopped using alcohol in the mid 80's). What is your etch, is it phospate free? Pending on the image of the day I agree with turbotom1052 and turn on the air curtain when you have lite image always helps.
FSA

 

Thanks everyone for your input, a guy goes to work every sunday and checks roller settings and calcium build up and does general maintenance i checked anyway but couldnt see any calcium, on Friday i did notice condensation on the roller shaft so maybe as one post says it could be the roller temp, it is very hot and humid here at the moment, unfortunately i dont have the authority to make adjustments to such settings ( the Japanese have a chain of command that i cant get my head around) anyway i will suggest adjusting the temp and also try the air curtain and see how i go
cheers

Dave

 

I don't think you can adjust the temperature for individual rollers or even units for that matter, at least with Technotrans, all I did was open the door on the operator's side of the unit in question and reduced the flow into the roller by turning the valve 45 degrees.

Shouldn't need a Japanese board meeting just for that?

 

Cheers Not A Gooner ,will try that mate, as for the board meeting ......mate you would be surprised haha....

Cheers

Dave

 

stripping problems

allright, after dealing with this issue for ten years, i have a solution that the chemical comps will not like. years ago nobody had this problem, but with our greener inks and solutions we do, i do not agree with the tempature theory, unless water is so cold and press so hot as to cause condensation. never beleave any company that says they never changed their formula, they do or their suppliers do or suppliers suppliers do. now remember less is best, fountain solutions are way to aggresive for todays ink, uor cyan had water on the ductor our yel was horriable, after years of the big companys not being able to solve this, i took matters into my own hands. i took a garden hose yes a garden hose and ran it to our cyan in 50,000 copys all yes all problems cleaned up. went back to fountain solutions and problems returned. next drained tenotrons tank and ran all pure water, press runs like a champ good starts good runs but may have to run 10% more water but i dont. just make sure to run a biocide in water to deter bacteria groth and change bios every couple months as to not let bacteria to become immune to one type. now your problem is solved, you just saved 40,000 a year on solution and you owe me a beer

 

I never thought i'd see the day

How long have you been a printer?

 

On the Heidelbergs that I have run, the air bars give the best solution to this problem. The extra blast of air to evaporate the extra fountain solution really helps... on every Heidi that I have run (GTOZ52 .. SORMZ.. SM102ZP.. MOV..)

 

The stipping issue in the rollers and the fact that the inks are jumping up after you run for a bit sounds to me like its an ink and water balance issue. Some of the guys I work with like to run their ink and water much higher than it needs to be and this will definately cause the ink densities to jump once the press settles in. The stripping issue can be caused by all of the excess solution in your ink train, the acid in the fount. can cause the rollers to become hydrophyllic. " The gum in dampening solution will desensitize plates at much lower pH values; however, the higher acid content may cause the gum to desensitize not only the plate images but also ink rollers, causing roller stripping- the failure of ink to adhere to the inking rollers. (Stripping that occurs at the beginning of the pressrun is usually caused by glazed roller surfaces, and stripping that occurs during a pressrun is probably caused by an excessively acidic dampening solution.)"=from the Sheetfed Offset Press Operating third edition.

Hope this helps.

Jae

 

Very interesting posts..thanks