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Need Help Print problem Roland BN-20

S

sekorse

New Member
Hello, I'm sorry to bother you again, but I'm having a problem with the print head... the yellow stops working from one print to the next and if I do a powerful cleaning then it works again, I don't understand everything is new in the head... (dampers... etc) see attached photo for example a printout with a red file, which prints pink depending on the printout
Screenshot_20231019_145048_Gallery.jpg
 
D

damonCA21

New Member
it sounds like ink starvation. When you do a cleaning the pump is quite powerful, so will pull ink into the head and damper. When you are printing normally this doesn't happen, so if there is a partial blockage in an ink hose then it can stop the ink getting through properly.
You need to check the yellow ink hose all the way from the damper back to the cartridge to check for leaks. Often the o-rings in the brass connecting nuts will leak letting air into the hose.
 
J

Jim Hancock

Old School Technician
You may want to remove the dampers and check and lubricate the O rings on both the top and bottom of the dampers, then reinstall them. See the attached service bulletin. This is something I've always done as standard practice, as it just made sense, even on DX4 style dampers. Lubrication is a good thing...
 

Attachments

  • Service Bulletin DX7_damper_seal.pdf
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adamfromayr

adamfromayr

New Member
Jim Hancock said:
You may want to remove the dampers and check and lubricate the O rings on both the top and bottom of the dampers, then reinstall them. See the attached service bulletin. This is something I've always done as standard practice, as it just made sense, even on DX4 style dampers. Lubrication is a good thingThan you Ji
Click to expand...
 
adamfromayr

adamfromayr

New Member
Thanks Jim

I will look into that this week i had a break fixing a Laser system just now The Dampers i will make sure to lube Being honest i think i still need a NEW DX7 head but cant afford one now so will have to wait a while till i pay of my credit cards!
 
adamfromayr

adamfromayr

New Member
Thanks, JIM Just reading that awesome PDF

I will download and print that off as its that good!

An excellent thing to share

Thank You Jim :thankyou:
 
S

sekorse

New Member
Jim Hancock said:
You may want to remove the dampers and check and lubricate the O rings on both the top and bottom of the dampers, then reinstall them. See the attached service bulletin. This is something I've always done as standard practice, as it just made sense, even on DX4 style dampers. Lubrication is a good thing...
Click to expand...
Hello, thank you for this article, I have well lubricated and reinstalled my dampers (still new, the 4th), however the problem persists ... I still have this problem of yellow, which is now worse and worse (no more yellow comes out except after several cleanings). I'd like to point out that the basic problem before replacing the print head was the same (the yellow was almost never printed except after several cleanings).
 
S

sekorse

New Member
Hello, I've already changed a LOT of parts but the problem persists... I've already changed :
- The print head
- the 4 flat cables of the print head
- motherboard fuses
- dampers (several times)
- the cap-top
- connection between dampers and ink tubes
- the entire ink circuit (tube, seals, brass screws)

After checking, I notice that there's a bit of liquid/ink on the edges of the cap top (see photo), do you think it's defective? I had the same problem (no yellow) before changing it...
 

Attachments

  • 1000016788.jpg
    1000016788.jpg
    1.6 MB · Views: 127
J

Jim Hancock

Old School Technician
First, make sure the ink cartridge has ink in it. Been there, done that... Felt stupid... If you rely on the display, be aware if you have ever pulled the yellow cartridge with the machine on, this display resets to 100%. Along with this is the possibility the empty flag on the cartridge did not trip the ink empty switch. Don't mean to state the obvious, but best to insure the obvious has been verified, not just ignored.

You may have a partially clogged yellow line or needle. Several cleanings would eventually pull a small amount of ink into the head, but it would run out quickly. First thing to do is to remove the yellow cartridge and look into the cartridge bay and make sure the needle is straight and not bent. Been there, done that... Next, I would suggest you pull the yellow dampers from the print head, attach a syringe to the damper, then pull the yellow cartridge out, and pull ink through the damper until the line clears with air. If you get resistance, do the same to the other yellow damper. If you get resistance still, the needle may be clogged. To be able to freely pull air through the ink line will insure it's not clogged. Based on your list, the needle may be the only thing that hasn't been checked. Again, verify!

I find these 2 items to be invaluable tools for ink system troubleshooting. #12 needle works on pretty much any ink connection on the Rolands.


 
S

sekorse

New Member
Hello, no the ink needle is not clogged because I was able to bleed the tubes to change them, the cartridge is new, there is no air in the tube, the machine filled itself when restarting after changing the tubes because I had done a bleed before.
 
S

sekorse

New Member
I even tried to make a Choke CL with the roland service technician software. This is recommended in the technician's manual when a color is missing due to air bubbles.
 
S

sekorse

New Member
The ink needle doesn't seem to be faulty, and the ink circuit is completely new from the cartridge to the printhead.
 
Zoogee World

Zoogee World

Domed Promotional Product Supplier
sekorse said:
The ink needle doesn't seem to be faulty, and the ink circuit is completely new from the cartridge to the printhead.
Click to expand...
Not that this is the solution, but have you replaced the pumps. It doesn't sound like the problem, as it really sounds like the damper, cap top or air in the lines, however, you've already replaced those parts.
 
S

sekorse

New Member
Yes cap looks OEM, it comes from the digiprint 6 month maintenance kit. I have a new pump included in the kit too but I haven't installed it, and it's not OEM, for the moment I still have the original one it's never been replaced.
 
Zoogee World

Zoogee World

Domed Promotional Product Supplier
sekorse said:
Yes cap looks OEM, it comes from the digiprint 6 month maintenance kit. I have a new pump included in the kit too but I haven't installed it, and it's not OEM, for the moment I still have the original one it's never been replaced.
Click to expand...
If it's from DIGIPRINT, it's most likely 3rd party and not OEM. Especially if it's in that kit, they are all 3rd party parts, at least all the ones I've bought in the past from them for our printers.
 
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