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VS-640: The Lost Channels

Fantazia

New Member
Hello, and I hope you are all well.

This post has the meaning to collect some ideas because I run out of them.
After 3 years of not intense but gentle usage of the 3rd DX7 printhead replacement of my VS-640 (Other 2 printheads replaced for the same reason: Light Cyan deflecting / misting) I had missing drops in Light Cyan and gradual disappearing - till total missing - Black, so I've decided to replace dampers and the one month old captop - just to be sure that they were not the problem. (All parts and ink are always OEM and the printer is clean, in factory shape and look).

After "by the book" parts replacement, I did a power clean and some test prints. Again, missing lines in Light Cyan and not a single line of Black.
So I did what the "book" says after damper replacement: a Choke Clean. While in Choke Cleaning procedure, the Yellow and Light Magenta
plus the White & Metallic (were replaced some years ago with cleaning fluid) disappeared from flowing.
Only Cyan and Magenta left in captop. Some power & medium cleanings followed, no result.
I used two syringes to suck ink from the captop lines, ink flowing smoothly
but again, 2 channels only - Cyan and Magenta.

I know that a broken print head can loose many or complete ink lines in test print, but no ink flowing in 6 of the 8 channels?
I know that Choke Clean is not the best practice for a printhead but is it possible to block ink channels?
Any ideas about this?

Thank you.
 

netsol

Premium Subscriber
just a guess, but, consider the possibility that you developed hairline cracks in the nipples on the manifold that the dampers sit on.
replacement dx7 damper is not a terribly expensive part, BUT, you have to have a delicate touch.

many people crack the manifolds when they change dampers.

i am 70 & i now let a freind/former employee who is in his late 20's do this sort of replacement for me.
 

Fantazia

New Member
just a guess, but, consider the possibility that you developed hairline cracks in the nipples on the manifold that the dampers sit on.
replacement dx7 damper is not a terribly expensive part, BUT, you have to have a delicate touch.

many people crack the manifolds when they change dampers.

i am 70 & i now let a freind/former employee who is in his late 20's do this sort of replacement for me.
Thank you for your quick reply. I' ve lubricated the dampers o-rings and print head manifold "nipples" with cleaning fluid to avoid any force on thema and to ensure tight sealing. As I said before, the missing channels occurred after Choke Clean. Not right after damper change.
 

Fantazia

New Member
are the dampers FULL?
any air gaps in the lines?
Yes, dampers are filled and there is no air in the lines. Checked many times. Is there any case that the printhead can block the ink flow AFTER choke clean? Printhead is in perfect optical condition, never ever had head crash, no delamination.
 

Zoogee World

Domed Promotional Product Supplier
Yes, dampers are filled and there is no air in the lines. Checked many times. Is there any case that the printhead can block the ink flow AFTER choke clean? Printhead is in perfect optical condition, never ever had head crash, no delamination.
How old is the cap top? It could be it isn't sealing correctly.
 

Fantazia

New Member
How old is the cap top? It could be it isn't sealing correctly.
Captop is replaced the same day with new dampers. OEM part too. Before cleaning I applied cleaning solution for better sealing. Head is in low position. Flush position is also adjusted to eliminate any factor.
 

Jim Hancock

Old School Technician
Correct me if I'm wrong, but it sounds like your problems gradually started with a captop replacement about a month ago and now won't go away with a new captop. I've attached a pic with 2 things to check - that the spring on the front of the captop (critical for head to captop alignment) is there and the 3rd nipple on the bottom of the captop has a little cap plugging it up. Either one of these can cause loss of adequate suction during cleaning or choke cycles. If both of those parts are there, then verify the captop to head alignment by what I call the ink chalk line test. Power the printer off. Move the head to the left so you can access the captop. Take a swab and get it soaking with waste ink. Wet the rubber lip if the captop with the waste ink. Lock the printhead in place. Unlock the printhead and move it to the cleaning station at the left side of the printer and examine the bottom of the printhead. If the alignment is correct, you should see an ink mark all around the head nozzle plate, but NOT touching the metal frame around the head. If it's touching the metal frame anywhere, then the capping station may need to be physically adjusted. Also, when you put the waste pump lines back on the captop nipples, they should fit very snuggly. If not, snip off about 1/4 inch and reattach.

BTW, the ink you were pulling through the cap with the syringe, what color was it? Smear a tiny bit on some vinyl to judge accurately. That could be a clue to help locate the problem...

You said you have replaced the printhead 3 times for Light Cyan misting and deflecting. The same issue 3 times leads me to think you have a noisy circuit somewhere, maybe the carriage board or the mainboard. Maybe Netsol or Damon have some thoughts about this...
 

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Fantazia

New Member
Correct me if I'm wrong, but it sounds like your problems gradually started with a captop replacement about a month ago and now won't go away with a new captop. I've attached a pic with 2 things to check - that the spring on the front of the captop (critical for head to captop alignment) is there and the 3rd nipple on the bottom of the captop has a little cap plugging it up. Either one of these can cause loss of adequate suction during cleaning or choke cycles. If both of those parts are there, then verify the captop to head alignment by what I call the ink chalk line test. Power the printer off. Move the head to the left so you can access the captop. Take a swab and get it soaking with waste ink. Wet the rubber lip if the captop with the waste ink. Lock the printhead in place. Unlock the printhead and move it to the cleaning station at the left side of the printer and examine the bottom of the printhead. If the alignment is correct, you should see an ink mark all around the head nozzle plate, but NOT touching the metal frame around the head. If it's touching the metal frame anywhere, then the capping station may need to be physically adjusted. Also, when you put the waste pump lines back on the captop nipples, they should fit very snuggly. If not, snip off about 1/4 inch and reattach.

BTW, the ink you were pulling through the cap with the syringe, what color was it? Smear a tiny bit on some vinyl to judge accurately. That could be a clue to help locate the problem...

You said you have replaced the printhead 3 times for Light Cyan misting and deflecting. The same issue 3 times leads me to think you have a noisy circuit somewhere, maybe the carriage board or the mainboard. Maybe Netsol or Damon have some thoughts about this...
Thank you for your detailed reply. I have the VS (from new) for about 12 years. In those years I have changed more than 36 captops. I replace them before they need replacing (about 3-4 per year). I have serviced this machine many times those years to keep it in top shape. In those years I have changed pumps, printheads, sensors, fixed the problematic choke valve tubes (white Max2 ink was a disaster) and any OEM part, every time needed. I mostly print product labels and photographic themes, so detailed printing is a must for me. DX7 heads give fine prints but they are not reliable. This time I am trying to figure out how the printhead can block the ink flow to captop in 6 of the 8 channels. If I solve this problem a pump-up and new head will follow with 8 to 6 ink conversion.

- The ink that came out when pulling with the syringes from captop was what I see on the captop after head cleans: Cyan and Magenta lines (mixing as violet in the syringe).

- Light Cyan misting (and black misting in one of the 3 replaced printheads) maybe caused because of the prolonged presence of cleaning liquid in the place of white and metallic. Cleaning Liquid is a emerge solution but not permanent solution, not good for printhead longevity. This is a good reason I want to go from 8 colors to 6 colors - no need for much changes in the ink lines as in the scheme I attach.
8 to 6 colors.jpg
 

netsol

Premium Subscriber
Correct me if I'm wrong, but it sounds like your problems gradually started with a captop replacement about a month ago and now won't go away with a new captop. I've attached a pic with 2 things to check - that the spring on the front of the captop (critical for head to captop alignment) is there and the 3rd nipple on the bottom of the captop has a little cap plugging it up. Either one of these can cause loss of adequate suction during cleaning or choke cycles. If both of those parts are there, then verify the captop to head alignment by what I call the ink chalk line test. Power the printer off. Move the head to the left so you can access the captop. Take a swab and get it soaking with waste ink. Wet the rubber lip if the captop with the waste ink. Lock the printhead in place. Unlock the printhead and move it to the cleaning station at the left side of the printer and examine the bottom of the printhead. If the alignment is correct, you should see an ink mark all around the head nozzle plate, but NOT touching the metal frame around the head. If it's touching the metal frame anywhere, then the capping station may need to be physically adjusted. Also, when you put the waste pump lines back on the captop nipples, they should fit very snuggly. If not, snip off about 1/4 inch and reattach.

BTW, the ink you were pulling through the cap with the syringe, what color was it? Smear a tiny bit on some vinyl to judge accurately. That could be a clue to help locate the problem...

You said you have replaced the printhead 3 times for Light Cyan misting and deflecting. The same issue 3 times leads me to think you have a noisy circuit somewhere, maybe the carriage board or the mainboard. Maybe Netsol or Damon have some thoughts about this...
Or that captop misalignment was misdiagnosed 3 times, or a slight suction leak (bad o ring) has been making the cyan ink a problem child.
 

Jim Hancock

Old School Technician
Good to know your level of expertise, makes it easier to help. I can see this is a strange problem that requires out of the box thinking. You said you have dealt with choke valve issues in the past, have you verified that it's working correctly? It seems to be the only common point for all the ink lines other than the printhead itself. If some of the tubes in the choke valves are stuck closed, this could cause your problem. I would attach a syringe to each ink line above the damper and see if you freely pull ink. You might also consider removing the ink cartridge for whichever line you are testing and see if you can clear the line and pull air. I would hazard a guess that with the level of meticulous (Awesome!) level of maintenance you do, your choke valve has been operated more than most users, and may need some checking for wear...
 

Ultraman

Ultraman
Hello, and I hope you are all well.

This post has the meaning to collect some ideas because I run out of them.
After 3 years of not intense but gentle usage of the 3rd DX7 printhead replacement of my VS-640 (Other 2 printheads replaced for the same reason: Light Cyan deflecting / misting) I had missing drops in Light Cyan and gradual disappearing - till total missing - Black, so I've decided to replace dampers and the one month old captop - just to be sure that they were not the problem. (All parts and ink are always OEM and the printer is clean, in factory shape and look).

After "by the book" parts replacement, I did a power clean and some test prints. Again, missing lines in Light Cyan and not a single line of Black.
So I did what the "book" says after damper replacement: a Choke Clean. While in Choke Cleaning procedure, the Yellow and Light Magenta
plus the White & Metallic (were replaced some years ago with cleaning fluid) disappeared from flowing.
Only Cyan and Magenta left in captop. Some power & medium cleanings followed, no result.
I used two syringes to suck ink from the captop lines, ink flowing smoothly
but again, 2 channels only - Cyan and Magenta.

I know that a broken print head can loose many or complete ink lines in test print, but no ink flowing in 6 of the 8 channels?
I know that Choke Clean is not the best practice for a printhead but is it possible to block ink channels?
Any ideas about this?

Thank you.
This is what you need to do! This don't happen to all VS but after 8/10 years it will start to occur with cyan or light cyan gone missing for no reason. Replacing print head or dampers or ink renewal will be short term fix. First of all make sure your pump is working good, your choke valve is your problem here. Remove the covers from the ink system at rear then remove your choke valve, the extended tube line for choke valve to clamp down (blue circle) and the tube line without the extended (red). All you have to do is snip away the extended tube end to end and joint a ink connector so that the ink flow will not have obstruction or dried ink. Since I have the ink system remove, I would also use a syringe to flush fresh cleaning fluid for your cyan and light cyan but make sure you disconnect your hose line cyan and light cyan from top of print head and place the two tube into a bottle then you can start flushing from ink system. Beware! next time if you want to replace your print head you will not have the choke valve to turn off the tube lines so therefore you need to clamp the tube lines from above dampers with forceps scissors. I do this few times and it works for me but its going to be messy so prepare with lots napkins and FORCEPS SCISSORS....good luck
xxyy.jpg
 

Jim Hancock

Old School Technician
Rather than bypass the choke valve, which is incredibly useful, replace the flexible tube that is pinched closed during the choke valve operation. Roland does not carry it anymore, but this should be a perfectly good replacement. It's the correct size, flexible and is solvent resistant.

 
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