White spots Roland 308 printing 4/4

[Piotr]

I have serious problem when printing 4+4 on Roland 308.
The side printing on the first 4 units looks terrible. I have a lot white spots which made my prints without contrast, and solids ( blue, red ) look grainy. The situation is worst if printing dark colors.
If I print 4+0 everything is OK even with perfector. It looks like impression cylinders make all white spots. Printing 4+1 I have less spots.
I checked all units from 5 to 8 and fund that each cylinder added spots. I observed that picture from the first side transfer to impression cylinder. Cleaning and applying Huber Cylinder Past doesn’t help.
I use Novavit 918 Bio inks, Alcohol 4%, Fount Printcom S 201 Q, pH 5,5 – 5,8, conductivity 1900
I attached pictures from microscope x40 and x200

View attachment white spots.pdf

 

[jay12345]

Your jackets are clearly the problem. It is going to mark no matter what you do but that result is bad. What brand of jackets are you using?

 

[Piotr]

Your jackets are clearly the problem. It is going to mark no matter what you do but that result is bad. What brand of jackets are you using?

This press (roland 308) has grainy, fixed impression cylinders ( no jackets). I am looking for solution to reduce this problem. Changing cylinders is too expensive.

 

[jay12345]

Don't perfect. Sounds rediculous I know. I can't see how a press could have fixed impression jackets as even the best jackets on the market have a short lifespan. That grain in the cylinder is going to aquire ink and build up marking the print. What do you clean those cylinders with?

 

[Piotr]

Don't perfect. Sounds rediculous I know. I can't see how a press could have fixed impression jackets as even the best jackets on the market have a short lifespan. That grain in the cylinder is going to aquire ink and build up marking the print. What do you clean those cylinders with?

There are two versions of Roland 308, one has fixed cylinders. The metal cylinders have grain surface, it;s the way Roland made cylinders for these machines. I try many cleaners with no effects. Do you recommend any?

 

[TheProcessIStheproduct]

Maybe expensive, but put a uv lamp before the perfecter, change out rollers for hybrid ink?

 

[jay12345]

we use shinoda's green frog jackets. I find them to be the best yet. we clean them ritually with prisco's aquaklene cut with water. i find that even babying them the way we do they still mark. so im not really sure what to do with a fixed jacket. The UV option sounds insane but is probably the only thing that will work. Plus then you can print on plastic.

 

[Freeman A.Gain]

There are two versions of Roland 308, one has fixed cylinders. The metal cylinders have grain surface, it;s the way Roland made cylinders for these machines. I try many cleaners with no effects. Do you recommend any?

I've used two types of cleaners for these kind of cylinders. The cheapest one, Easy-off oven cleaner, the liquid(not the spray). Cleans like a damn, but the smell can be a bit much, even for a pressman! The other one, which is more expensive, but works well and can be left on overnight for a deep clean, is called Recyl Clean 2000. This stuff is fantastic, but around $100 a bottle.

 

[Alois Senefelder]

Puzzled

Puzzled

Piotr,

Are you saying that when printing 4 back 4 - the First Side is transfering ink onto the Impression Cylinders ?

1) Ink Piling just in the Image Areas on the cylinders ???

2) Because the Images PDF Look Snowflaky !

3) The Impression Cylinders are - Matt Chromed

4) Post a picture of the Imp. Cyl.


Regards, Alois

 

[Piotr]

Maybe expensive, but put a uv lamp before the perfecter, change out rollers for hybrid ink?

This is a solution. I will check cost.

 

[Piotr]

I've used two types of cleaners for these kind of cylinders. The cheapest one, Easy-off oven cleaner, the liquid(not the spray). Cleans like a damn, but the smell can be a bit much, even for a pressman! The other one, which is more expensive, but works well and can be left on overnight for a deep clean, is called Recyl Clean 2000. This stuff is fantastic, but around $100 a bottle.

Thanks a lot. I've ordered Recyl Clean 2000

 

[Piotr]

Piotr,

Are you saying that when printing 4 back 4 - the First Side is transfering ink onto the Impression Cylinders ?

1) Ink Piling just in the Image Areas on the cylinders ???

2) Because the Images PDF Look Snowflaky !

3) The Impression Cylinders are - Matt Chromed

4) Post a picture of the Imp. Cyl.


Regards, Alois

I guess, that ink pilling is just in the image area on the Cylinder and printed image looks like snowflake ( see the last picture)
The impression cylinders are mat steel with a little grainy surface.
Additionally I attached new picture of impression cylinder