Grit in roller train

[New uv printer]

Good day fellow printers,

I have been having a problem lately with a lot of grit in my roller train. I have tried washing it out but have not been very successful. I could do a Calcium slayer and hot water rinse every evening just to try to stay after it.

Has anyone seen this before? We are switching from pacesetter rollers to boettcher and it's on both brands of rollers and in every unit. Currently we are running a toyo medium tack ink and a prisco one step fountain solution with alkaless 6000 added. It's an 8 color 106xl press. Here are a couple of photos.

Thank you for your help

 

[Cornishpastythighs]

Have your ink company do a grind test. Are you using an RO unit. Have you investigated your paper/board

 

[New uv printer]

Have your ink company do a grind test. Are you using an RO unit. Have you investigated your paper/board

I will say something to our ink rep. To be honest with you I have not really checked the paper but we run multiple different brands.

 

[Asures]

Quick Questions -

Are you running standard Mercury Vapor or LED/HUV inks?

Do you have light filter covers over your lights above press? Is the ink demonstrating a "hide" or clumps after some time in the ink fount?

Could be the ink's monomer / oligomers are diving into the rubber. That can certainly be a possibility. Highly unlikely you're going to have a bad mind of all four colors. You'd experience extreme plate wear, especially in screens.

 

[New uv printer]

Led uv inks, no we do not have light covers but we have testing our lights to make sure it's not drying up the ink.

I showed this to a trainer and he said it's normal for uv presses.

 

[Asures]

Led uv inks, no we do not have light covers but we have testing our lights to make sure it's not drying up the ink.

I showed this to a trainer and he said it's normal for uv presses.

I personally service A LOT of UV, H-UV, and LED offset shops (everything from high end commercial to packaging) on all types of presses from Heidelbergs, KBA's, Komori, RMGT's. These shops are running process and in and out of PMS colors all day and I don't see that.

Where I have seen this occur, it was a combo of factors. Either the inks are prematurely curing and what you're seeing is some residual pigment after your wash-up or the monomer/oligomers or diving in the rollers and leaving stuff behind. I've seen this incompatability with Hybrid Roller Compounds (not saying you go back and forth). Doubtful you have a bad grind in all four colors, as stated.

If you tap out some of your inks on bare stock and set them on the delivery of the press, check them in a few hours or the following day to see if they've cured. The amount of ink in the fount is considerably greater than microns on the fount ball or even on the rollers, hence you not seeing ink clumps. The nm (nanometer) range for LED inks is really tight - 385 - 395 and it really doesn't take a lot to get the inks to start to cure.

Are you seeing any lines (rat tailing) on the fount balls? Are you experiencing your ink fount liners cracking after a few days? Did you use a Radiometer to check nm output from your overheads?

I'd strongly advise getting light covers/sleeves over your bulbs. You can get them online from UV Process Supply (www.uvprocess.com). Inks may cure at different speeds once the photoinitiator has been incorporated - like LED Fluorescent inks and LED Metallics, which both have short shelf lives and can be somewhat hybrid formulas.

Feel free to call me. Happy to help!
562-378-8418 Aaron

Lot of questions but just trying to assist...

 

[New uv printer]

Thank you greatly for your help Aaron, I really appreciate this.

Here I will try to answer all your questions.

We run strictly led uv ink.
Yes we have tested ink on bare stock by the fountain ball for several day, no problems there.

Yes I am replacing my liners on Wednesdays, (we are only a one shift shop)

And yes the ink does eat through if I don't. I have noticed the ink being milled by the friction of the ink ball rotating and the tension from the liner.

Here are a couple of photos. Thank again.

I personally service A LOT of UV, H-UV, and LED offset shops (everything from high end commercial to packaging) on all types of presses from Heidelbergs, KBA's, Komori, RMGT's. These shops are running process and in and out of PMS colors all day and I don't see that.

Where I have seen this occur, it was a combo of factors. Either the inks are prematurely curing and what you're seeing is some residual pigment after your wash-up or the monomer/oligomers or diving in the rollers and leaving stuff behind. I've seen this incompatability with Hybrid Roller Compounds (not saying you go back and forth). Doubtful you have a bad grind in all four colors, as stated.

If you tap out some of your inks on bare stock and set them on the delivery of the press, check them in a few hours or the following day to see if they've cured. The amount of ink in the fount is considerably greater than microns on the fount ball or even on the rollers, hence you not seeing ink clumps. The nm (nanometer) range for LED inks is really tight - 385 - 395 and it really doesn't take a lot to get the inks to start to cure.

Are you seeing any lines (rat tailing) on the fount balls? Are you experiencing your ink fount liners cracking after a few days? Did you use a Radiometer to check nm output from your overheads?

I'd strongly advise getting light covers/sleeves over your bulbs. You can get them online from UV Process Supply (www.uvprocess.com). Inks may cure at different speeds once the photoinitiator has been incorporated - like LED Fluorescent inks and LED Metallics, which both have short shelf lives and can be somewhat hybrid formulas.

Feel free to call me. Happy to help!
562-378-8418 Aaron

Lot of questions but just trying to assist...

 

[Asures]

Based on your pictures, the inks are curing on the fount ball. As they are curing on the ball roller, then are collecting debris (cured ink) and creating uneven pressure between the liner, ink keys, and last fount ball. Get the overhead sleeves and get a thicker ink fount liner (.12 or .14mil) instead of the regular conventional ones. They‘ll last all week for you.

Black is going to be the most the most aggressive in curing as it has the most aggressive photo packaging incorporated in it. Generally, Yellow shouldn’t be too bad as it’s the most transparent but again, without the sleeves on the lights, all will prematurely cure. Just note the Blacks and Opaque Whites are the most difficult to cure.

That “Grit” in the pictures is residual pigment after the ink’s monomer/oligomer is done (fancy way for saying vehicle) diving in your rollers. You can “Condition” the rollers with UV Reducer (Liquid Monomer) every week for a few and that will minimize the leaching into the rubber.

 

[New uv printer]

Based on your pictures, the inks are curing on the fount ball. As they are curing on the ball roller, then are collecting debris (cured ink) and creating uneven pressure between the liner, ink keys, and last fount ball. Get the overhead sleeves and get a thicker ink fount liner (.12 or .14mil) instead of the regular conventional ones. They‘ll last all week for you.

Black is going to be the most the most aggressive in curing as it has the most aggressive photo packaging incorporated in it. Generally, Yellow shouldn’t be too bad as it’s the most transparent but again, without the sleeves on the lights, all will prematurely cure. Just note the Blacks and Opaque Whites are the most difficult to cure.

That “Grit” in the pictures is residual pigment after the ink’s monomer/oligomer is done (fancy way for saying vehicle) diving in your rollers. You can “Condition” the rollers with UV Reducer (Liquid Monomer) every week for a few and that will minimize the leaching into the rubber.

 

[New uv printer]

Thank you very much for your info, I greatly appreciate it. We will be trialing some thinker steel liners within a week or two so I am hoping that helps. I also was told to heat up some water/solvent a 20% solvent to 80% water mixture and run that after my washup which greatly helps.