We have a 2075 in our print shop that puts out good dark copies at the beginning of a job but as the job goes on the copies get lighter and lighter
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When you stop a job, does the machine run on, add toner and recover CQ without you adjusting anything?
If yes, it sounds like the I.D system is working, but the TD sensor may have a problem. What's the output on SP2223(TD)? and3103 (Vsp / Vsg)? when the copy is good.
Any Service codes? (340 / 341 / 342?)
Is SP3901 on?
If the TD sensor is down the machine will use ID and Pixel control, so if and the pixel control rate is also low, the copy quality will drop during a run. You could try using SP2507 as a temp solution. this will develop an I.D patch during the run which should retone the machine. try SP2507 -1 at "1" and -2 at "50" -
Base on your given reading, you ID sensor is cover with toner.Comment
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Doubtful! As vsg is 4,25v. However, I should also have asked for the reading of SP3001-1. If this is very high (approaching 255) it could be an ID fault, if not, since you seem to have enough toner in the dev (assuming it was set up correctly) it's more likely drum earth degrading during the run. Clean the shaft / bearing / discharge brush behind the flywheel.Comment
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I checked sp3001-1. Its somewhere around 50.Comment
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Right, If the ID intial setting is 50 the ID sensor is not dirty! Do you have the reading for SP2223 when the copies are good and bad? What are the settings of SPSP3901?
Does the job contain large solids? Have you tried the SP2507 settings I suggested?
Have you checked the drum earth?Comment
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Ok so, the drum earth stays clean through out a big job(200 copies)
Sp 2223 starts at 343v. 347vat 90 copies. 350v at 200
Sp 3103-1 stays the same 3.82v
Sp 3103-2 starts at .72v. 1.21 at 90 copies. 1.82v after 200
As far as large solids i was using a test page from konica with a gray scale and dark picture.
And i used the 2507 setting and that has been working greatComment
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Good info... At the end of the job does the ID patch recover without any action?
How old is the drum? It looks like the machine may be trying to compensate for fatigue during the run, the drum may not be discharging which may explain both the light copies and light ID patch. When the machine develops a patch during the run it will add toner to boost the ID to 0.5v, but IF the drum is old this MAY lead to background eventually. It's odd that even with toner added via SP2507 you are still getting a high (1.5v +) reading during the run.Comment
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I'm unsure about the patch recovery. Not there to check now. But i know the drum is getting up there in age. We have a couple of drums here for that machine so i think I'm going to go ahead and replace it.Comment
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How did the drum change go, ?
the dev units seem to do this a lot, may need a new unit ( shot blasting inside apparantly wears smooth) at around 3 - 5 millionComment
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