Print head problem (Officejet 6500A Plus)

[ninj]

Hi

I'm have print quality problems with my HP Officejet 6500A Plus. I tried refilling the original (intro) cartridges by injecting OCP ink via the vent hole, but was getting flow problems. After trying various things I removed the print head and soaked it in hot water in case there was a blockage. After refitting the print head (having allowed it to dry) the print quality report showed a series of horizontal white across the black bar. Loads of head cleaning cycles didn't help, neither did another soak. I even tried flushing it through with a steam cleaner (risky, I know) but that didn't improve things. Have I damaged the head by soaking in hot water, or is it possible that some dried black (pigment) ink has got lodged somewhere it shouldn't as a result of cleaning? (I've scanned the print quality report but can't yet embed URLs as a new member.)

Jon

 

[ninj]

Print-quality report here:

Is it possible to tell from this whether the print head is either blocked or damaged?

 

[websnail]

Oh boy... I don't know how the 6500 is setup so this is pure guesswork (and I mean that literally)...

Your approach to refilling may well be part of the problem as any ink injected via the vent hole is likely to result in the vent hole becoming clogged with dried ink so that's already a potential vector.

Next up the black ink is likely to be a pigment ink and based on my experience with the HP88 black this is rather prone to clogging, especially if the refill ink introduced is a dye base ink.. The scenario is different due to the HP88 printhead design but I developed a routine of flushing the printhead through thoroughly by printing off a ton of pure black pages until the pigment ink was pretty much gone and only dye ink remained. The best replacement dye I found was the Image Specialist 190 black which is actually an Epson Dye... That breaks a ton of rules in the book but there's always exceptions and this was one of them.

Whether this information is of any relevance to your particular printer or setup I can't tell you but hopefully it's of some use.

Good luck...

 

[ninj]

Thanks for your reply. The replacement black ink is also pigment based. It think the reason for the clogging is that after my initial (and, with hindsight, unnecessary) attempt at head cleaning I left the head to dry out completely for a couple of days before putting it back into the printer. Any residual ink must have set hard (and there probably was some residue as I only soaked it in hot water, without ammonia or anything). I've now found some old ammonia (9.5% solution) and will make up a cleaning solution and try injecting it through the inlet nozzle. Is 1:10 (ammonia solution:water) about right?

I guess a better solution would be to try to get a replacement print head under warranty, but I'd prefer to fix it myself.

Cheers.