Diagnose my printhead problem

[Guest]

I've got an old DesignJet 1050C (yes, it still runs!). I'm having some problems with the black printhead. On startup the printhead runs great, but after about 1 page, it starts to crap out. Here's a photo of the test image. Notice that the print starts OK at the top (albeit there's a bit of a strange thing going on in the top line print that is only present on the black). In the bottom color runs we have solid black at the top and then it starts crapping out toward the bottom. The printer thinks the printhead is OK and the ink is at around 35%. A clogged printhead I would think would have the opposite result (i.e. crappy at the beginning, but perhaps getting better as more ink flows and the clog is dissolved). It's almost like it's running out of ink??? Maybe whatever pump that brings the ink from the ink resevoir is not working well? Maybe the ink has dried up a little and is a bit sludgy?

Anyway, this is my personal printer and I don't want to replace a bunch of stuff that I don't have to. (everything on this plotter is expensive!).

[rszimm]

Re: Diagnose my printhead problem

UPDATE: Ran the printhead clean program again and got this: https://i.imgur.com/tw9CCvI.jpg Notice how the crosses in the middle almost totally did not print. Also notice how the border of the #2 section didn't print. It's almost like the print head is just losing communication for a brief period of time or something. Not sure. Anyone?

[Phil B.]

Re: Diagnose my printhead problem

UPDATE: Ran the printhead clean program again and got this: https://i.imgur.com/tw9CCvI.jpg Notice how the crosses in the middle almost totally did not print. Also notice how the border of the #2 section didn't print. It's almost like the print head is just losing communication for a brief period of time or something. Not sure. Anyone?

1) Get simple green cleaner... paper towels... fold towel to fit flat in track for PH travel...soak towel in SG
2) power on printer...when carriage moves 1/2 way out pull cord
3) place soaked towel in PH track
4) WITH POWER CORD out of wall..gently push PH back over the towel
5) leave for 1hr
6) push head back on middle..remove towel and wipe cleaning station wipers & docking cap.
7)remove from printer... power up ..run cleaning program again

[D Hook]

Re: Diagnose my printhead problem

Love those old 1050C printers. I have a couple.

Looking at the pictures, it looks like the printhead is giving up. Cleaning might work for a little while.

Also, check on the back of the printer where the clear hoses go and make sure you don't have bubbles or clear spots in the black tube. As these printers get older, the seals in the ink station get hard and don't seal as well and air gets into the lines which then starves the printhead and can burn it out. But they still make very good rebuilt ink stations with all new seals and are sold on ebay. Also, LPS sells the rebuilt units too. Designjet Store

No affilitation, just a satisfied customer.

[Kiran Otter]

Re: Diagnose my printhead problem

I agree with D Hook; you likely have air in the tube(s). You can use a syringe to suck some ink out and remove the air, but unless you print every day, it will just come back. Replacing the tube assembly is a better fix.

Also once you get air in the printhead, it's unlikely to function correctly even after replacing the tubes (or removing the air.) Plan on replacing the prinehad as well.

And I highly recommend LPS Computer. I've used dozens of their tube assemblies.

Kiran

[rszimm]

Re: Diagnose my printhead problem

I agree with D Hook; you likely have air in the tube(s). You can use a syringe to suck some ink out and remove the air, but unless you print every day, it will just come back. Replacing the tube assembly is a better fix.

Also once you get air in the printhead, it's unlikely to function correctly even after replacing the tubes (or removing the air.) Plan on replacing the prinehad as well.

So I'm back with a quick update. I bought a cheap black printhead off Amazon and it seems to have cleared up the issue. However, in diagnosing this issue I did look at the tubes and noticed that every color EXCEPT black has an air pocket in the tube. What's weird is I've never had any problems with the other colors. They print just fine and always have. Is air in those tubes a definite problem that needs immediate attention or can it still function with some air in there? I just hate to spend $299 for a new ink assembly (I only paid $250 for the whole printer!).

[Kiran Otter]

Re: Diagnose my printhead problem

LPS sells a syringe specifically for priming or removing the air from the tubes.

Designjet Store

If it's a little bubble, you can probably ignore it. If there's large sections of the tube with air in it, I would remove the air before it gets into the printhead.

Kiran

[rszimm]

Re: Diagnose my printhead problem

LPS sells a syringe specifically for priming or removing the air from the tubes.

Designjet Store

If it's a little bubble, you can probably ignore it. If there's large sections of the tube with air in it, I would remove the air before it gets into the printhead.

Kiran

Are the check valves at the print head that keep air out located in the print head itself or in the part the print head plugs into? Are those serviceable without plopping down $250 for the whole assembly?

[D Hook]

Re: Diagnose my printhead problem

Available on Ebay:

Ink Nozzles Connection Assy for HP DesignJet 5500 5100 1050 5000 4000 z6100 USA | eBay

I've never tried them myself so can't vouch for them.

The LPS syringe is the best one to use because of it's shape.

[Kiran Otter]

Re: Diagnose my printhead problem

That's interesting. My concern with something like that is that the hose it's pushed into, is unlikely to seal well when put back together. You'd probably have to epoxy it in. That's if you can take the tube assembly apart without breaking it, too. And $20 for just one? Hmm.

I've never taken that piece apart to see what's actually inside; I believe it's just a rubber o-ring or pierced rubber disc that seals up when the printhead is removed. It also looks like the silver part is crimped on, so I don't think you could remove it without destroying it.

If you print on a regular basis (like at least every other day or so,) I don't think you'll have as much of a problem with air getting in the tubes. It seems to happen more when the printer sits for long periods of time without use.

Kiran