T520-new printhead keeps getting sketchy after a few to several hours

[pbrooks259]

On a T520 with a new printhead and new ink, the printhead keeps getting sketchy after a few hours or sitting overnight on the service station (pic attached of diagnostic print). The attached pic shows it just after overnight, after several hours. It only has about a 320 page count; I think this is accurate.
It clears up after printing some or doing a printhead cleaning. So it seems to be drying out or getting covered with some ink. It just seems to be a partially dried out printhead nozzle after sitting idle for a few hours on the service station. Seems it would take longer than a few hours, like several days or a few weeks. I have assumed that the printhead nozzles are not being adequately capped off by the service station and therefore it is drying out. Black seems the least affected. This is the 2^ndI have only worked on a few of these; still getting familiar with them.

Thanks.

[blackcat4866]

Re: T520-new printhead keeps getting sketchy after a few to several hours

I have not worked on this particular capping assembly, but on previous HP models it is primarily a mechanical device that gets gummed up with dried ink.

Were it me, I'd try this:
I'd remove the capping assembly, and remove any electronic components (includes wiring harness) that may be damaged by water. Then I'd fill a bucket with hot water and submerge the capping assembly in the hot water. Work the mechanisms as well as you can to free them up. Use a toothbrush to scrub anything needing scrubbing. Take care not to lose any small parts that come loose as you clean. Eventually the water will get too murky to clean well, so change out the water and continue.

I have changed a few suction units over the years, but the majority just needed a good soaking. It takes about 4 days for your hands to return to their original color. =^..^=

[austonrush]

Re: T520-new printhead keeps getting sketchy after a few to several hours

When you installed the new printhead did you install it with the 4 brand new ink cartridges it ships with?

Does the printhead dock properly over the service station once a plot has been completed?

Is this a pre-existing issue or did it only arise after replacing the PH?

[pbrooks259]

Re: T520-new printhead keeps getting sketchy after a few to several hours

Thanks for all the info. I will probably clean up the service station and see if that helps. After 300 some odd prints the service station should not be worn out. But perhaps the rubber parts of the service station could be a bit dry rotted due to age, mfd. 2016.

Yes, I installed 4 new cartridges along with the new printhead.

I am not 100% sure it docks properly over the service station; I'll have to check. If it does not dock properly over the service station, I assume that would be caused by an obstruction, or what else? Bad encoder strip maybe? ....I've never really had one not dock properly over the service station...except for maybe the last T520 I worked on that seemed to do the same exact thing.

I don't know whether it was pre-existing as I got it with a bad printhead. The problem arose for me right after I installed the new printhead and new cartridges, but that is the 1st time it worked for me.

Again, it clears up after printing about 3 to 4 or 5 diagnostic prints or immediately after performing a printhead clean.

Again, it seems it simply sits atop the service station and dries out. I will try to check and see if it is docked properly over the service station. It gets worse with time--the longer it sits without printing.

Thanks very much.

[austonrush]

Re: T520-new printhead keeps getting sketchy after a few to several hours

It's quite possible the PH is defective. If you can get it replaced under warranty, start there, then you know!

[pbrooks259]

Re: T520-new printhead keeps getting sketchy after a few to several hours

I THINK it was NOT docking properly over the service station--it seems that it was about 3/4" to 1" away from the right end side plate; I don't think I am misremembering. I cycled power and now it seems to dock properly on the service station. I don't know why it would not have docked properly over the service station previously. Do you?

Austonrush, you seem to talk like you have had one before not dock properly after printing. Is that right?

I'll see what happens.

....Replacing a printhead under warranty seems to be a mystery to me. Doesn't appear to be an obvious process to me.

[blackcat4866]

Re: T520-new printhead keeps getting sketchy after a few to several hours

As far as "not docking correctly" goes, I'd disengage the capping assembly and move the carriage to determine if it is moving smoothly. Ink beads tend to build up on the carriage rail and encoder strip near the service station. You may feel resistance of the carriage to move in that area.

Clean the carriage rail with alcohol, and lubricate the rail with Canon EU-1 carriage rail oil.

Canon EU-1.JPG

I do not suspect the encoder strip. You would have image quality issues associated with that (continuously) ... sawtooth breaks in should-be-straight lines. You'd recognize that right away. =^..^=

[pbrooks259]

Re: T520-new printhead keeps getting sketchy after a few to several hours

Blackcat, thanks.

[Kiran Otter]

Re: T520-new printhead keeps getting sketchy after a few to several hours

The service station is only $80, I'd just replace it if there's a concern. And make sure the encoder strip is clean; if it's got ink on it this could easily throw off the position of the carriage over the service station.

Kiran

[pbrooks259]

Re: T520-new printhead keeps getting sketchy after a few to several hours

Yeah, the service station is relatively cheap about $100 plus. I lubed up the carriage rail some and cleaned the encoder strip some. I will see how it performs now. ....I think possibly the carriage's positioning over the service station was thrown off possibly leaving it uncapped to dry out. I will see how it does tomorrow--see if it prints sketchy again. Thanks.

[pbrooks259]

Re: T520-new printhead keeps getting sketchy after a few to several hours

Update (maybe premature): I cleaned up the encoder strip especially above the service station, and I lubed the carriage slider rod a bit more above the service station. The carriage seems to be homing in better on the service station. (Again, I think the printhead was a bit half-cocked on the service station capping station and therefore the printhead nozzles were drying out over night.) Thanks for bringing up the idea that the printhead may not be properly positioning over the service station! I swear I have NOT encountered this on any other model! If I did, I THINK it at least threw up an 86:01 SE code...had a T770 that had some ink on the encoder strip over in the vicinity of the SS but it threw up 86:01 as I recall.

This morning after sitting powered on all night I printed the diagnostic image and all colors were printed appropriately. I was relieved! Whew! Hope it keeps it up!

Thanks guys!

Printheads on these things SEEM to go bad in a wild fashion especially of course matte black IMHO.

[blackcat4866]

Re: T520-new printhead keeps getting sketchy after a few to several hours

Congratulations!

They have a mylar seal on the top of the printhead, and I had a customer somehow pierced that mylar ... ink everywhere! When I arrived the printhead was sitting on the counter in a puddle of ink and the covers open ... maybe this could be the problem?

Funny, nobody seemed to recall how the printhead got out of the machine ...
=^..^=

[austonrush]

Re: T520-new printhead keeps getting sketchy after a few to several hours

Glad to hear that suggestion helped. Yes, normally most plotter throw a code when the carriage assembly isnt going back to the correct home position. But with the T520 and T530 I have had this a couple times. Ink overspray on the encoder and a dirty rail seem to stop it from parking correctly and yet no error! good work

[daprex]

Re: T520-new printhead keeps getting sketchy after a few to several hours

....Replacing a printhead under warranty seems to be a mystery to me. Doesn't appear to be an obvious process to me.

I usually just call hp support, and talk with them and send a diagnostic file, ive replaces a few printheads and a few ink cartridges that stopped working.