MP 2550 PCU

[Chicko]

Re: MP 2550 PCU

Whenever you have a unit sitting for more then a month I always do a developer agitation. This helps the machine get new readings and re-adjust. Also if you machine is sitting for that long be careful (and yes I know this sounds weird but I've experienced it more then once) with your toner as it sometimes goes "bad" and will need to be changed with new toner.

[peterxu256]

Re: MP 2550 PCU--TD and/or TC etc

I met such case several times. Thinking a lot if there is the better solution, sometimes it is quite beyond a tech control. Because it will re-occur again after 15K to 20k much less PM target due to software control limitation of Toner Density Adjustment (Vsg, Vsp, Vsdp, Vt, Vts or Vref). Manual doesn't say details about relationship among "V values), common issue is concerned with Toner concentration too high. I guess toner control is heavily relayed on Vsp(ID sensor pattern. The same drum's Vsp value changed largely from 1.17, 1.05, 0.56, 0.31 etc. Is someone willing to offer these logical values theory.


I also find a strange issue on Ricoh MP2000, Vt value is always greater than Vref , but doesn't add toner. i.e. Vt=2.33 Vts=2.15. margin difference is below 0.30v(monitoring several days for testing purpose) After making 10 Sky Shot copy, triggering toner end, then Vt 2.78v Vts=2.23v(difference is 0.65v). The last copy's density is still very high by physically checking. After Toner End Recovery, it read Vt=2.35v, Vts=2.23v. Increasing Vref limit from 3.20 to 3.3v (Sp2929-01)
Still allow to make 10 Sky shot, no more. What else SP mode to change will make it more difficult for the Toner End condition to be triggered when TC is really low physically. Is it TC really high or Low for that value? But making 50 copies using a text-based original. output density looks like normal. I confused a lot. Usually Vt below 1, TC is counted High.

Some advisory explanation is appreciated. thanks