Take our HP 360 Latex for example, I spent some time this morning running 'clean printhead' operations then running the Printer Information report immediately after:
This is the first report, prior to me running a clean, it shows some nozzles on the printheads 'out':
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| Report 1 |
So I run my first clean, and after, refresh the report:
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| Report 2 |
To be fair, it 'shows' that they ARE unblocking, so I run another clean, then refresh the report again:
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| Report 3 |
Oh wow! Looks like I'm making some progress based on the results from that previous report, so I do a fourth clean (the OCD in me thinking I can get those numbers even lower...)
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| Report 4 |
Nope. What WAS I thinking! So now the optimiser printhead loses the plot and the previously misbehaving magenta printhead is getting clogged up again.
In-between reports 2 and 3 I do some plot tests and sure enough there ARE nozzles out on the magenta and they DO come back after a targeted clean (i.e. I do the clean ONLY on the magenta/yellow printheads). However the plot test shows the black printheads as perfectly okay despite there being nozzles consistently out.
So I do another clean, thinking maybe the optimiser printheads will unblock because, strangely, they were fine based on the first report:
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| Report 5 |
...aaaand... No! They just start getting worse again!!
I gave up at that point and just ran a image quality test, which looked acceptable... to most people, but not to me because I KNOW there are nozzles not working!
In conclusion, I think HP just runs a routine in the printer firmware that randomises the output of the printhead nozzle numbers, that way, us peon print-operators use-up ink from doing continuous cleans, forcing us to buy more than we need.
