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Well, here we go again! Only 3 weeks after replacing our 4880 print head and getting really good results, our printer has again stopped power cleaning properly. And now it has stopped printing in all eight channels.
Last time this happened, we disassembled the capping station, verified that the vacuum pump was operating properly and was clean, and very carefully drew ink from the ink lines right up thru the damper valves. Finally, after nothing else worked, we replaced the print head. Magically, power clean vacuum operation returned.
That seemed to fix the problem, so we accepted that somehow the entire print head had become clogged (all 8 channels!) and moved on with production. Not fun in the middle of the Christmas printing rush.
Here we are three weeks later, and in the space of only an hour or two we've gone from a perfect nozzle check to nothing ... no ink being squirted from *any* of the 8 channels. Doing a power clean shows that no ink at all is sucked thru the ink lines (and the ink level in the tanks hasn't changed after 4 cleans). It's as if the vacuum pump has failed. The waste tank sponge is dry.
Our print shop is kept at 60% RH and 21C temp at all times, so it shouldn't be an environment problem. We always do normal head cleans at least twice a day whether we print or not, and the capping station is always kept moist with a few drops of diluted HD cleaning fluid. Shirt pre-treatment is done in a location completely isolated from the print shop, so that isn't an issue.
I've opened another support call with the US Screen folks, and tried their suggestions to no avail, but would like to ask if anyone out there knows of any way to verify that the seal between the print head and the capping station is really working.
I find it hard to believe that a 3-week old print head would very suddenly stop working on all eight channels during a power clean. So we're out of production, feeling rather frustrated. I *do* like the BlazerPro, and I remain optimistic this will be solved, but twice in less than a month? .....)
Put a little liquid in the capping station and do a simple clean, this will tell you if the pump/capping station assembly is working correctly.
Dan "HAPPY PRINTING"
__________________ www.DTGInks.com "Where help is always there, just for the asking"
Put a little liquid in the capping station and do a simple clean......
Thanks Dan. That's the weird part ... the pump seems to clear fluid from the capping station during a regular clean cycle. Well, actually, the fluid will slowly drain away all by itself in a short time, but it clears faster during a normal clean. The pump could still be leaking in that case.
I wish there were some way to trigger the pump all by itself so that I could observe its behavior with the print head moved away from the capping station. It's not just a simple dc motor ... it has a rotor-position sensor that gets in the act. (And it's a real pain to get at!)
With a syringe I can gently pull ink thru the damper valves (something I'm not fond of doing). It's the sudden failure of power cleaning in all 8 channels that has me mystified.
I do recognize that disassembling the print head (to check the dampers) would have introduced air into the print head, and it's the power clean cycle I need to fix that. Is there any sane/safe way to check if fluids can flow thru the print head's internal channels below the damper valves?
To make events a bit clearer: We ran a nozzle check, which was perfect on all channels except #8. Channel 8 showed complete blockage at that time. We then tried to do a power clean to clear that channel, and at that point it was easy to see that no ink was flowing in *any* channel when the valve levers were moved downward after building up a vacuum. That doesn't seem logical right after having gotten an almost perfect nozzle check.
I don't think hooking up the shopvac to the print head is a very good idea but it would certainly move a lot of ink (just kidding!).
Are you positive that your capping station seal is clean and or not damaged? same with your wiper blade? one nick or a bad seal will not cause the vacumm to work correctly.
Dan "HAPPY PRINTING"
__________________ www.DTGInks.com "Where help is always there, just for the asking"
Are you positive that your capping station seal is clean and or not damaged?
That's exactly the million-dollar question. The rubber seal around the station is flexible and kept scrupulously clean. Same for the wiper blade, which gets cleaned every time we do a regular head clean.
I just checked again under a bright light, and I noticed that when I run my finger along the top edge of the station seal, it does feel a tiny bit rough but it's quite flexible. Could this be the cause despite the apparent strong upward spring pressure? How long are these seals supposed to last?
The funny thing is that we had the same problem earlier, and it seemed to be fixed by replacing the print head.
I had another chat with US Screen this morning and they're pondering what to do next. They seem as mystified as we are here, which is understandable. I understand that replacement capping station seals are not too expensive, so perhaps that's the next step. I dread the thought of taking it apart again
I do not think that you can just repalce the seal, you will have to purchase the whole capping station if you decide go that way, it cost around $145.00
Dan "HAPPY PRINTING"
__________________ www.DTGInks.com "Where help is always there, just for the asking"
Thanks so much for your suggestions, Dan. I'm beginning to think we should pro-actively replace the station, since it's likely something that has to be done eventually in the life of any 4880. Not cheap, but perhaps necessary. I believe this is called "learning the hard way".
I wonder if the rubber seal is simply not totally compatible with HD cleaning fluid? Especially this latest batch which we find to be thicker and with a tendency to foam up a lot. Our original problems appeared at some point after we started using the new HD cleaner.
To be fair, I don't think Epson designed the 4880 for use with water-based DTG materials in the first place.
Re: BlazerPro (4880) Power Clean Problem (Again!) (Maybe solved)
US Screen support comes thru again
I'm happy to say that the folks at US Screen seem to agree with my general assumption. In further tests, and a very close inspection, I discovered that for whatever reason, the upper edge of the capping station seal has become almost invisibly serrated. I can actually feel it when I draw my finger very lightly along the seal on all four sides, especially on the left and rear edges. A bright light and a dental cleaning tool revealed that it's not an accumulation of dried ink, it's the rubber seal itself that has acquired a rough edge. I have no idea why this would happen, but it makes sense that it could cause enough air leakage to prevent a build up of vacuum during the power clean process.
At any rate, US Screen voluntarily offered to replace the capping station assembly since the printer is still under warranty. We'll know later next week if it fixes the problem. In the mean time, we're keeping lots of moisture in the station to keep the head from drying out.
Are you positive that your capping station seal is clean and or not damaged? same with your wiper blade? one nick or a bad seal will not cause the vacumm to work correctly.
Dan "HAPPY PRINTING"
Dan "HAPPY PRINTING"
__________________ www.DTGInks.com "Where help is always there, just for the asking"
Thanks for the heads up Dan, it proved to be the correct approach!
Y'know, the folks at Epson must think we're all a bunch of weirdos, using their printers this way. But, given the piezo print head technology, it actually makes sense. It's the ink formulation that generates most of these issues, but on the flip side of the coin it's also the only kind of ink that works, so we're caught in the middle. Willingly so, I might add
I have come to respect the overworked US Screen support folks because they've gone the extra mile more than once for us over the past year. Truth be known, I also love digging around inside the Blazer because I'm a serious tinkerer at heart with an engineering background. It's fascinating to learn how these machines work, but I obviously have a lot more to learn!
Sounds like now what you need to know is-what caused the degradation of the capping station seal? If it is as you suspect , that the new cleaning solution is not compatible with the seal, you do't want to damage another seal verifying it.
If your other print head is still around you might take the time to see if it can still be flushed out with a syringe- perhaps you can have a back up print head out of the situation.
This is a discussion about BlazerPro (4880) Power Clean Problem (Again!) that was posted in the Direct to Garment (DTG) Inkjet Printing section of the forums.
BlazerPro (4880) Power Clean Problem (Again!) 
Re: BlazerPro (4880) Power Clean Problem (Again!) 
