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07-09-2019 10:53 PM
I have HP Latex 25500 printer. It is keep missing Black head or blocking Black head. I did following things.
Yellow is good all the time only Black is clocking print head
1) Replaced 5 times Yellow-Black print head with brand new.
2) I broke one print head to check if ink is coming in that or not but it is full of Black & Yellow ink.
3) Replaced Black cartridge with new date. But no luck...
4) Check pressure of air by going Service mode. All ok.
5) I check each parts in service mode & all show me result ok.
6) Flush Black ink by pulling out from carriage nozzle. Manually & from service mode. All good.
7) No air or leak in tubes.
😎 Drop detector is also working.
9) Use worm water & soak print head. It unblock some nozzle & work good but again next day block only Black.
10) I used Isopropane, Metho. Spirit, Soap water, Amonia cleaner everything work & unblock few nozzle but next day same result.
11)All nozzles of crane type air assembly is good.
12) Removed right side cover & check everything is working properly while printing & all good.
13) Crane assembly pushing air in print head.
14) Service station working good.
15) Changed Aerosal fan assembly with filter.
16)Change cleaning cartridge.
17) Update firmware with new.
18) Reset EROM for service menu.
19) Called HP technician & paid money.
20) Called private technician & paid money.
But no luck at all. All technician don't know perfect solution. Please help me if anyone know solution.
07-12-2019 07:09 AM
Thanks for reply. If problem in Print head cable it suppose to give error. It show me warning when I start printing.
""""Print quality problem.....something like that "it you press ok it start printing without black.
I also keep side printing bars on from rip. It is printing all bar colours with print without Black.
It is printing beautiful just this problem only. Please help...
07-12-2019 08:01 AM
check weight of printheads, if printhead is lighter - not enough ink is going into from tubes:
- take a look at ink towers (where printhead needles are going into - recently we replaced ones causing same as your case - empty PH's and only one ink is missing . When checking - all PH's weighted around 60 grams, only one was 45 grams... - in this case all checking passed OK and when cleaning was made - ink was present, but when printing - one of two colors from PH was missing...
- sometimes PIP's from ink cartridges are defecting (no need to be leaking just not pumping enough ink);
- check tubes for air...
If you're checking only one printhead so far and making tests only with it and not with another one - may be it's defective after all...
07-12-2019 09:29 AM
FYI. If you are looking to dig into technical details, explore how to produce new applications or share your tips and tricks with your colleagues, the HP Latex Knowledge Center has outstanding information that can help users of this type of product. Here is the link for the HP Latex Knowledge Center. HP Latex Knowledge Center.
HP Latex Knowledge Center
07-12-2019 09:16 PM
Tooo many sensor in HP printer that cause all software problems & firmware problem. Just need few sensor like vinyl plotter.
Media in or end of media so printer stop
take up roll media
& temperature sensor.
That is what I think.
07-16-2019 12:22 PM
Check that the rubber nibs are still on the Primer assy. (It looks like a Crane over top of the Carriage when the carriage is parked at the right side)
The purpose of the primer is to help the ink flow through the Printheads with air pressure.
If any of these nibs are missing then the PH's are not being primed properly and will cause them not to push ink through.
As HP does not sell the nibs separately (they are hard to get on properly) you will have to replace the complete primer assy.
07-16-2019 03:35 PM
Yes I have checked last month when problem start. At that time some times getting black. All looks ok.
If rubber nib is not seating properly on Yellow-Black print head & not priming. Technically Yellow & Black both should missing because it is on same print head. I replaced several print head but only Black missing or jam ink. Yellow is absolutely good all the time. Crane assembly working fine & **bleep** is seating properly.
Appreciate your reply.
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