MPC 2500 colour shadow on top third of copy

[spaniel ears]

I've got an MPC 2500 with about 130k black and 37k colour on the clock producing a coloured shadow usually magenta or yellow around the black print on about a third of the copy on the rear side. The rest of the copy is fine and the shadow is only beneath the print, almost like a 3D effect, if I copy the meter reading printout in colour the shadow is the same thickness as the black line. SP 2111 forced line position adjustment a,b and c all fail and after 3 attempts i'm getting an SC 285. I've just whipped the transfer belt, laser unit and pcus out of the machine and i'm off to try in another customer's machine, just wandering if anyone has had the problem before in case none of the above are at fault when I try them.

Cheers.

[E Winter]

If the color registration is way out of sync the machine won't be able to adjust itself sometimes - you'll need to perform some sp procedures in this case (I think there's a chapter about this in the service manual). The initial problem may be caused by a light image density (common issue under very low volume conditions - 37k color isn't a lot) -> the ID/MUSIC sensors aren't able to read the registration patterns. You can force the machine to toner up via sp and run a td-sensor initialisation afterwards.

Dirty/faulty sensors or the transfer belt may be the cause as well but so far I only had issues with light image density leading to bad color registration.

The "top third of the copy" part sounds a bit odd though - maybe you can upload a sample scan?

[spaniel ears]

Cheers Jan, the density isn't too good on the colour at the moment, not horrendous just a bit on the pale side, and auto colour calibration fails as well so i'll have a look at that next. I've just been to try the laser unit, transfer belt and colour pcus in another machine, they didn't show the fault there but the machine i've got the fault on has been doing it intermittently at times so i'll take the results with a pinch of salt. I'm not able to scan a sample at the moment but i'll try and upload one tonight.

[TonerMunkeh]

When's the last time it had a set of PCU's and an ITB cleaning unit? The worn cleaning unit could be wiping the ID sensor patches off the belt affecting the line position adjustment.

[spaniel ears]

When's the last time it had a set of PCU's and an ITB cleaning unit? The worn cleaning unit could be wiping the ID sensor patches off the belt affecting the line position adjustment.

The colour pcus are the originals, not been replaced yet as far as I know.

[TonerMunkeh]

They'll be well over life then. They'll need replacing, along with a new ITB cleaning unit, oil supply roller and oil roller cleaning roller. After that, run line position adjustment C then A, process control Pre-Acc then normal, then ACC it. It'll be happy after that.

[E Winter]

Cheers Jan, the density isn't too good on the colour at the moment, not horrendous just a bit on the pale side, and auto colour calibration fails as well so i'll have a look at that next.

Definetly. The PCU's (Drum&Development Unit) are running very well if the machine doesn't print much high coverage wich usually overstrains the cleaning unit inside the PCU wich in turn leads to a wax/toner built-up on the charge roller. If this is not an issue I wouldn't recommend a huge parts slaughter if you can solve this problem with toner-add & td init. Of course there are other things to consider (service contract yes/no, remaining time of the contract, journey time.....). The PM cycle for the drum units is 80k, 160k for the dev and 320k for the dev unit. Dunno why but time-depending (over the yers..) aging is not really an issue on these units (from my experience). I just got a MPC2500 from 2006 with 18k color printouts back in the shop and there was no need to replace the drum units during refurbishing the unit. I wouldn't bet that the units last another 4 years but there may be no need if the next customer is going to print more color.

The oil roller is probably dry so changing the fuser cleaning rollers and checking the fuser belt for cracks is probably a good idea.

[spaniel ears]

Cheers lads, looks like image density was the problem I think. Cleaned all PCUs, transfer belt cleaner box, ran process control manual execution image density adjustment then line adjustment C and A, all completed. Auto colour/registration adjustment now fine and copies ok. Obviously i'm gonna have to start thinking about replacing PCUs etc somewhere down the line, i'll see how it goes for now.

[E Winter]

thanks for the feedback

The image density adjustment does usually only slightly increase the toner level in the dev-mix. There a SP called "Fore Toner Supply" where you can toner up the machine manually. Usually I run this SP for ~10 seconds, run the process control and print a test pattern. If needed i repeat these steps until the coverage looks good. Then I use the "new unit set" sp to tell the machine I've installed new developers wich leads to a TD sensor initialisation after turning the machine off/on.

[spaniel ears]

thanks for the feedback

The image density adjustment does usually only slightly increase the toner level in the dev-mix. There a SP called "Fore Toner Supply" where you can toner up the machine manually. Usually I run this SP for ~10 seconds, run the process control and print a test pattern. If needed i repeat these steps until the coverage looks good. Then I use the "new unit set" sp to tell the machine I've installed new developers wich leads to a TD sensor initialisation after turning the machine off/on.

Cheers Jan, that's handy to know, copy quality was pretty decent as I left it but i'll tone it up a bit if I get any further problems.