I have an HP 4000TN that started out with a dark print and eventualy started to print lighter (using OEM 27X Cartridges). The Fuser, ECB and a new 3rd party Transfer roller were installed. Laser/Scanner lens and mirrors were cleaned. And evened preformed a "half-test". The toner cartridges were printing Font pages from The Information part of the printer for test purposes. The top of the page that has a solid Black strip with the white block letters PS Font List on the left are truly dark the way it is intended to be about half-way to the right-hand part of the same image, it starts to get light and blotchy. Can it be the Laser/scanner itself? Is there a way to test the unit (laser/scanner)? Thanks<Steve
HP 4000 TN
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OMD-227
From the Service Manual......
Engine TestThe printer has one test pattern (vertical lines). When an image
defect appears, a test print can be made to identify the problem. The
test print can be made by pressing the test print switch located on the
left side of the printer.
A test pattern can be printed by pressing the test print switch once after the
photosensitive drum has stopped and the printer has entered the
standby mode. If the switch is held down, the test pattern is printed
continuously. The switch can be used when paper is loaded in any
tray other than Tray 1.
The Engine Test does the following:zVerifies that the print engine is functioning correctly (the
Formatter PCA is completely bypassed during an engine test).
zIs used for isolating printer problems.
zIs used for checking and adjusting registration.
zPrints from Tray 2, 3, or 4 only, not from Tray 1.
zCan be activated with the Formatter PCA removed.
NoteFor the printer to perform an engine test, Tray 2, 3, or 4 must be installed
and loaded with paper, and the Toner Cartridge must be installed in the
printer.
Location of Engine Test ButtonThe engine test button is located on the left side of the printer, belowthe fan vent,
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I've performed as suggested
I produced 4 samples and they all have the same void light line area on the trailing or bottom right side of the page...Stumped againSteve
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OMD-227
Any chance of scanning a sample page and attaching here?
I dont know enough about the paper path design on the HP printers to offer any more advice. Been fortunate enough not to touch them over the years.Comment
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HP 4000 TN
When you cleaned the laser scanner, did you physically remove it from the printer, open the top and clean the lenses? Check to make sure there are no obstructions in the shutter.
Is the transfer roller even or is one end higher than the other? (If you do, then you might have a broken transfer roller clip, in which case you would need to replace the paper feed guide asm - see other post in HP forum for instructions) You could also have a defective transfer roller (even happens with OEM rollers)
Check the HVPS contacts that touch the cartridge and make sure they are clean.
Oh...and make sure economode is off.Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well-preserved body, but rather to skid in sideways - Coke in one hand - chocolate in the other - body thoroughly used up, totally worn out and screaming "WOO-HOO, what a ride!".Comment
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Great suggestions prntrfxr. I only have one thing to add.
Check the protective light blocking shutter for the drum, on the toner cartridge. If it is hanging crooked it can block the light path from the laser causing light areas in your prints (all prints). In a pinch these light shutters can often be removed with no harmful consequences. The cartridge just needs to stay in the machine, away from room light. In most cases this is not a problem. =^..^=If you'd like a serious answer to your request:
1) demonstrate that you've read the manual
2) demonstrate that you made some attempt to fix it.
3) if you're going to ask about jams include the jam code.
4) if you're going to ask about an error code include the error code.
5) You are the person onsite. Only you can make observations.
blackcat: Master Of The Obvious =^..^=Comment
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