# Dampers?



## Stitch-Up (May 26, 2007)

I read this forum a lot and learn from those who've been into DTG printing a long time and are willing to share their knowledge and experience - thanks.

I often read that dampers should be routinely replaced, maybe yearly or more often. Why? I'm not questioning the advice at all but I like to know the reason why these small plastic things should be replaced? What actually goes wrong with them if they're not changed? Is it possible to see the 'damage'? Once 'damaged', can they be recovered?

I ask the questions all in the quest for a better understanding of the component parts which together, make up the DTG printer.


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## zoom_monster (Sep 20, 2006)

John,
A damper serves a couple purposes. If you take a damper and look at it, you will see that it's a chamber which ink enters from the bottom, goes through a larger chamber that also includes a filter element. The chamber will help swirl the ink and mix it just before it exits(about half way up) and goes to the nozzles. Because ink is composed of a liquid and suspended solids, this makes the mixture more consistant. The top of the chamber will also trap gasses that are disolved in the ink or that enter the tubing or connections. Because pigment will settle and clump together, the filter screen in the dampers will prevent these "boulders" from entering the small nozzles and causing cloggs or missfires.

You can either replace the dampers or switch them out with a spare set and clean them by purging and backwashing them with proper cleaning fluid, distilled water and by using an ultrasonic cleaner if you have one handy. Eventually you will want to replace, but if you have an extra set and proactively change them out, you can get a lot of value out of them AND keep you printhead happy


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## Stitch-Up (May 26, 2007)

Thanks for the explanation Z - another step along the long learning curve answered.


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## calynd (Jul 21, 2009)

That is a very good question and great reply

can I re-ask the bit about when do you know when they need changing? what signs do you look for? 

Hope you don't mind me jumping in


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## Stitch-Up (May 26, 2007)

Not at all, I more often learn from questions asked by others


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## DAGuide (Oct 2, 2006)

calynd said:


> can I re-ask the bit about when do you know when they need changing? what signs do you look for?


When you start seeing you are having ink starvation issues more frequently that require more head cleanings to get the ink primed in the print heads. What typically happens is the filter will get clogged and prevent the ink from flowing to the print head properly.

Hope this helps.

Mark


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## Resolute DTG (Jun 27, 2010)

calynd said:


> That is a very good question and great reply
> 
> can I re-ask the bit about when do you know when they need changing? what signs do you look for?
> 
> Hope you don't mind me jumping in


They also act as a one way valve, a tell tale sign is when the first print of the day has a slight tinge of colour to it. This is due to the damper letting ink back up through the print head from the capping station.


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## equipmentzone (Mar 26, 2008)

Just to clarify, the damper that Zoom Monster posted a diagram of is used on the Anajet printer. John has a 4880 based printer and they use the damper style shown below. These actually feed ink in from the top of the damper.

As he mentioned, all dampers are wear items. To get the best performance you should change them out as part of a scheduled maintenance plan. We recommend, at a minimum, at least once a year.

Harry
Equipment Zone


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## calynd (Jul 21, 2009)

Thank you for your answers - and for letting me join in 

We have ink starvation problems so sounds like it is time to change the dampers (we don't have a dtg printer - we have a large format printer but our dampers look like the first picture which is why I joined in)

Thanks again - off to order some new dampers


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## Stitch-Up (May 26, 2007)

Thanks for all the replies, most helpful.

So what makes the ink flow? The carts are below the level of the printhead so what lifts the ink into the dampers to the printhead?

Cheers

john


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## equipmentzone (Mar 26, 2008)

Stitch-Up said:


> Thanks for all the replies, most helpful.
> 
> So what makes the ink flow? The carts are below the level of the printhead so what lifts the ink into the dampers to the printhead?
> 
> ...




You would first prime your dampers by pulling through the ink using a syringe. The capping assembly does it from there on, acting almost like a vacuum cleaner.


Harry
Equipment Zone


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