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Synaux
05-30-2014, 02:07 AM
First let me just shoot out there that I am well aware of most if not all of the IU fixes/mods/issues discussed on numerous older threads. That being said, I feel inadequate having to post this, but still hopeful.

There are 3 machines with the same general behavior ONLY on black:
< - - - - - -
< - - - - - - -25180

This scan is not great and a little washed out, but this halftone print (from Service Mode) is perfect on the dark end; however, it exponentially lightens towards the back on the machines/prints.

HV contacts cleaned, PH cleaned, switched around tranf rollers/belts and fusers. Played musical chairs with the IUs and even manually replenishing toner.

Ran/reran Reset/Stabilize & Gradation.
Then I messed around with TCR 3, DMax +10 and ran 250 sheets with almost no coverage and reduced the fade by about 50% on one machine.

I then installed a new IU that immediately exhibited the same results on the two machines I have tried it in so far.
At that point it was time to go home.

Table Numbers:
VDC-K:
399 Machine #1
333 Machine #2
410 Machine #3

VG-K
~490 Machine #1
~450 Machine #2
~500 Machine #3

Level History = Good
IDC Output = Good
All machines in a decent environment with ESP protectors (2 machines are at the same location and the other elsewhere).


Thats about everything my scrambled brain can recall right now.

Thanks in advance!

Rolandito
05-31-2014, 01:07 AM
I think the IU K is not seating correctly.
There is a fix for that...Try to give more pressure on iu unit ...

mascan42
05-31-2014, 06:05 AM
Also make sure that there isn't developer spilled onto the print head window. I see that A LOT on C550s that didn't have the IU making good contact.

Synaux
06-04-2014, 06:49 AM
I think the IU K is not seating correctly.
There is a fix for that...Try to give more pressure on iu unit ...
Thanks for the reply
I have the bracket mod installed and even wrapped some tape around them to make them more robust.


Also make sure that there isn't developer spilled onto the print head window. I see that A LOT on C550s that didn't have the IU making good contact.
Again thanks for the reply
I cleaned the PHs.

I seriously doubt that this is an issue of dirty machines as it is replicated on three machines (and I keep the machines I work on immaculate). Either way, I will remove a PH and inspect it.

I have not been back yet, but what really freaks me out is that the new IU did what the old ones were doing. I have been thinking about this and the only thing I can think of is that the new IU was an OCE IU chipped for konica; however, the old IUs were OEM konica...?

Its possible, but three bad HV1 boards...? Possible, but unlikely.

Printer People
09-22-2014, 10:37 AM
Ive got this exact problem - take the problem IU out and put a known good one in and its is perfect. The drum started of perfect and gradually got lighter towards the back.

Its obviously a problem IU but what is the cause and effect - dont want to scrap just about new £300 image units. Does anyone have a fix? I might try it in a different machine and try to manually tone it up - see what happens.

EarthKmTech
09-22-2014, 01:58 PM
stupid question, but are you sliding these iu's in straight out of the box ?

I've found repeatedly if you do this without agitating the settled contents by rocking / shaking the iu before installation as instructed they fail within a week to a couple days.

Etech
09-23-2014, 12:32 AM
Is this the same with the other colours ? if so tbu might be suspect ?

Synaux
09-25-2014, 02:43 AM
stupid question, but are you sliding these iu's in straight out of the box ?

I've found repeatedly if you do this without agitating the settled contents by rocking / shaking the iu before installation as instructed they fail within a week to a couple days.

I have been told to do this by other and do it.

However, the little instruction manuals for OCé make IUs state
"Do not shake the black imaging unit"

I am still unsure to what exactly happened, but I tossed that new IU and swapped the HV board from a parts machine in the first machine I used the black IU in. So far, things are going well...

Synaux
09-25-2014, 02:44 AM
Is this the same with the other colours ? if so tbu might be suspect ?

Only on black...color me stupid, but what the heck is a tbu?? :confused:

Etech
09-25-2014, 07:46 AM
Only on black...color me stupid, but what the heck is a tbu?? :confused:

Glad you got it sorted tbu is, transfer belt unit.

Synaux
09-25-2014, 11:37 PM
Glad you got it sorted tbu is, transfer belt unit.

Oh lol

GTgosu
12-11-2014, 08:33 PM
i have the same problem so Synaux (http://www.copytechnet.com/forums/members/synaux.html) i try to
replace:
transfer belt
HV board 1/2
Toner supply section
Developer in IU
Drum in IU

after that i bought a new IU, after 2k copies problem returned.
I don't have any idea how to fix this.

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