bring back the black

[Vinyldog]

My SP540V has had trouble printing black for awhile. Today I tried just unplugging the leads to the print heads and it seemed to help a little as you can see by the before and after nozzle checks. Yes, I did plug them back in before printing.
True or false, if the Cyan is printing fine, the problem cannot be the black / cyan print-head?

 

[HDvinyl]

That looks like you could syringe it out.

 

[Solventinkjet]

True or false, if the Cyan is printing fine, the problem cannot be the black / cyan print-head?

False. Although those colors print from the same head, they have completely separate channels of ink and electrical signals. Each color also has different pigments that affect the head differently. Each color is used in different proportions as well which means that the black could have more fires than the cyan.

Usually when one channel of a head is bad and the other is good, the first thing I look at is the dampers and manifold area. If the damper is old (more than a year or two) or there is air in the ink line, change it. Take the damper off and check the manifold for cracks or damage. If everything looks good, move on to the cap top. If it hasn't been changed in more than a year or has even the slightest damage, change it. After that, make sure your pump tubes are clear and not clogged (probably not the issue but worth checking).

One other thing to check is the bottom of the head. If there is a lot of ink build up, it will cause the head to not seal with the cap top and won't clean properly. If all else fails, try to flush the head with cleaning solution and a syringe. This is a last resort option as it can do more damage to the head if you are not careful. If that doesn't help, unfortunately, you will need a new head.

 

[ChaseO]

I once saw a Roland tech take the cleaning solution and a swab, and dab the actual head while performing a regular maintenance clean. As soon as he was done printing, he immediately printed blocks of straight black. It did clear up the text prints considerably. He also warned me that this was a last ditch effort and to not do that in ordinary circumstances. It would appear that you have nothing to lose though. For the record, after miles and miles and miles of prints and many years of faithful service, I have only replaced the black/cyan head one time, when my test prints started looking about like yours. Prepare yourself for a new head just in case. Good luck.

 

[Vinyldog]

Thank you to everyone for your advise. This printer has had this problem off and on for several years now. Each time I do something I think I have it fixed but it comes back. I think the manifold will be a place I will start to look at closer because I have changed the dampers several times and I could have been too forceful at some time.
I think I will also just unplug everything and plug in back in as it did seem to do some good on those two ribbons.
Short of calling RAS I'm reduce to replacing things until I hit the right spot so I want to start with the cheapest ones.

A technician did look at the usage log and virtually every replaceable part is past it’s expected service life. This machine is eight year old.
I’m curious, does the pump at the front of the machine directly under the cap station only pump ink through the heads for cleaning or does it also provide pressure for printing?

 

[player]

Change the caps.

 

[Vinyldog]

I have not replaced the caps since May2015 so that service is due, and I could also change the damper again as that has remedied the problem in past.
Back in Feb. I also used the cleaning cartridge which brought it back into tolerance for quite a while, and I did the thing where you squirt ink down the tube with a syringe. Almost everything I try seems to fix it for awhile. That's what keeps me from calling for service, I think there is some minor detail I'm overlooking.
It's a shame because the other three patterns are in such good condition. I just printed several yellow banners with red letters that turned out beautiful.

 

[player]

Just change the caps first. If the caps don't seal, then the pump don't pull, then the ink don't flow, and the heads get clogged.

Plus they are exposed to air. While you're at it change the wipers as well. Both caps. Make sure to use Roland parts.

 

[Vinyldog]

I've been using the manual method of lowering the cap-station, using the metal tube that you twist from below when I work on the machine. The caps are touching the heads so I don't think it's not brought up enough but I wonder if maybe I have brought it up too high?
Once again, I would think if that were the case it would be affecting the other three colors as well.
It' been almost a year since I have seriously tried to fix it. Learning to use my Latex machine has kept me a little distracted. But I think I will do everything we have discussed shortly and see what happens.
But, my feeling is I will replace the black / blue head in the end.

 

[Vinyldog]

Today I unplugged and re-plugged the ribbon cables on the mother-board, resulting in the best nozzle check pattern I ‘ve seen in two years.

 

[player]

Be very careful plugging and unplugging the cables. It is easy to blow a fuse. Not the end of the world, but it does add to the stress levels.

 

[Vinyldog]

same story

No fuses blown, but nozzle check went back to very poor after printing one job, and that job didn't look very good. I thought I would try putting the cleaning cartridges back in and pulling ink / fluid through the head with the syringe, but after connecting the hose from the cap I pulled the plunger all the way out twice with only a trickle of black ink coming out.
So guess I will work my way back to the cartridge again pulling ink from each connection and replacing the cap and damper. I don't have a new damper in stock but I have an old cyan that should be usable if I blow it out with cleaning fluid as I have had no problem with printing C.
It appears turning the sub-power off which I did before unplugging the cables may be what helped the test print.