I think you may need to give everyone a little more information.
Why are you needing to perform "cleaning runs" - I have never performed a cleaning operation (except in the cleanup after a major fault) on my printer and it is over 18 months old? Also, if you have replaced all the heads - why does it need cleaning - they are new heads and should perform like new (no clogged nozzles)?
The only thing I can suggest without further information is that you have some sort of malfunction where the printer is telling you to clean heads? I'm guessing here. It may be a fault with the drop detector - maybe it can't detect any drops and therefore thinks there is a problem with the heads??
Hope this helps,
I never needed to perform manual cleaning runs. But recently it has had banding, and on performing the print head test pattern it showed blocked nozzles. I did one have the error message saying the drop detector needed cleaning, so I cleaned it and the messages stopped, making me think that it was now clean.
I don't really know what more info I can give. The prints have banding on them, so that suggests dirty blocked nozzles, especially when the pattern test sheet is printed. The drop detector is clean, if it wasn't performing properly surely it would put up the error message?
I could put in a new drop detector, I believe they are only about £20. Then think again if the problem persists.