blanket glaze

[thunderbird press]

im getting it alot on the outside of the printing sheet and occasionally in the print areas. the affected areas are super glosses and print with a blur. any ideas? tried rejuvenator and deglazer on blankets with no results.

 

[SteveSuffRIT]

Trying to better understand your issue?
Are you talking about "picture framing" where area outside of press sheet on blanket collects ink?
On thin caliper paper, it may transfer to back/impression cylinder.

Blanket glazing is typically when the blanket itself does not readily accept ink because of accumulation from gum Arabic (fountain solution) or calcium carbonate (coated paper).

This versus that?
Does it happen on all units/colors?
Does it happen on all types of paper, uncoated vs coated?
Is it happening on all presses?
Does it happen on new blankets?
Can you show some photos of plate, blanket, press sheet?

 

[thunderbird press]

Does it happen on all units/colors? Randomly yes
Does it happen on all types of paper, uncoated vs coated? Not sure as it only shows on blankets
Is it happening on all presses? One press
Does it happen on new blankets? All blanket types
Can you show some photos of plate, blanket, press sheet? Will do when I get it again

Its like a glossy area which prints a thicker dot than normal

we've tried everything and the only thing that works is putting on a new blanket

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[thunderbird press]

this is after a deglazer treatment and then hit with rejuvenator

 

[SteveSuffRIT]

I don't know how to interpret your photo?
Is that area glossy/shinny because it's still wet and wasn't wiped dry with a rag?
Does either the deglazer or rejuvenator make the blanket swell up and become tacky?
Hydrophilic (water-loving) materials, like gum Arabic, acid/etch, calcium carbonate (paper, ink) produce glaze over time, from exposure.
Those types of materials can only be removed with water, not solvent.
That's why many printers use a water "miscible" solvent wash for blanket/rollers, it already contains some proportion of water in the mixture.
In the old days, we washed the blanket twice, separately with solvent then again with water.
To reduce downtime, we dunked the rag in a water bucket, then squirted solvent onto the rag, one rub gave a mixture of two (2) things.

 

[thunderbird press]

that gloss stays even when the blanket is completely dry
and yes we tried using water first. it does nothing.

 

[drukman]

Could you please tell me what machine it is for? What year was it manufactured?
..just out of curiosity...

 

[SteveSuffRIT]

That glossy/glazed area, is it clear/transparent or will it be the color of the ink on that unit?
Are you a commercial printer (on thin paper) or a packaging printer (thick board)? I ask because the blanket usually does not come into contract with back impression cylinder for board.
Are you using conventional oil-based ink or a UV ink?
Do you wash blankets manually by hand or do you have auto-blanket washers?
Is the size/shape and position/location always the same?

 

[thunderbird press]

1998 Man Roland 330 series
Label stock mainly
auto washers-- conventional ink
its always in different areas

 

[SteveSuffRIT]

Not sure I have anything else to contribute, sorry.
What has your blanket mfg said about this?
What do you/your pressman think it is?

 

[thunderbird press]

no one has any idea, ive given up and just put on a new blanket. other press operators are blaming my fountain solution as i am on a one step now