BizHub 750 doc feeder skew, I think?

[Desert Rat]

This is very odd for me. I was checking the registration of the doc feeder.
I usually fold a piece of paper in half and make a mark in the crease. I will
do this for the top to bottom and left to right. So a portrait 8.5X11 will have
four marks one in the center of each side.
Make the copy and fold the paper. Both top and bottom are in the crease,
but the left and right ones are not. Nor are they both on the same side of the
crease.
Is this the "incline" adjustment I saw in the book? It is like twisted but not.
I used the #16 printer target to set up the printer and was unable to adjust
the physical position of the feeder to remove the skew.

Anyone got some advice for this problem?

Thanks

DR

[CraigW]

Are you aware of the skew sensors under the black plate held by 3 screws ?? If you get paper dust buildup on the black plate it will cause skew from radf. Clean the plate and the sensors and see if it solves it for you.

[Desert Rat]

CraigW,
Thanks for that info. I was not aware of the skew sensors. I will check and clean them.
Yesterday I went back to this machine and just started with the printer and got the
print registration down to spec, made a couple of minor adjustment for the feeder and
it seems to be good now.
Today during a final check out I start getting a jam with LTR R paper in tray four. The jam
code is 1701. "The registration sensor does not come on after the loop sensor is on."
I can run the same job from tray 3 without any trouble. The run was 2 pages in doc feeder,
1-2, tri-fold, 10 sets.
It always leaves one sheet out of the #4 tray, still in the nip of the rollers and one on its way through
the fuser.
I swapped feed assemblies tray 4 with tray 2. Ran tray 2 without a problem. Put new OEM tires on
and then ripped the sep tire for tray 4. So I guess I'm going back tomorrow.
Also I'm getting some dirty edges from time to time. Could this be caused by old developer?
I saw the drum is rated at 500K, how much can it be pushed?
I am prepping this unit for a customer and the sales guys want to cheap it out.
I'd be happy to hear any advice.

Thanks

DR

[CraigW]

Dirty lead edge is the nature of the beast...esp if near a PM, developer is 250k, and 500k is about the limit on the drum.

I sometimes run several sky shots or 36 mode #1 prints to detone, only a short fix.

Never tore a tire yet. Always blast them with simple green so they wont rip.

[Desert Rat]

I will give the simple green a shot, I usually just make the hub wet but was in a hurry and did not
get it wet enough.
The dirty edge it just on the top and bottom lead edge about an inch long from the edge of the
paper.
Do they normally overtone or run dirty? This machine is going to a printer, how much trouble
am I getting into?

DR

[CraigW]

Yes, the hub.

These machines can and do overtone & drop toner onto the T/S. Our 600s are doing pretty well though. PMs and required adjustments should be done on time by the book.

Have you cleaned the drum carriage and recycle section ?? And the area below the mag roller ?? They can both hold and drop a lot of toner.

[Desert Rat]

CraigW,
Thank you for the advice. I will be changing the drum & blade plus developer
and corona's today. I noticed when I first looked at this machine the transfer
charger and erase lamp had lots of toner on them. I will pay close attention to the
areas you have mentioned.
Will this machine run after market toner from Precision Roller?

Thanks

DR

[CraigW]

Yes, the toner dumps at each end of the T/S corona.

Have no experience with 3rd part toner.

If you are changing those items you need to reset the counters and perform the adjustments in the correct order.

[Desert Rat]

Yes I have changed the corona wires in both charger assemblies. I have also changed the
the dev mix and was in the process of replacing the drum and blade. Much to my surprise
the drive cog in the front does not fit in the new drum. I have the Imagistics 7520 model.
And the drive cog is different by about .5mm and that one side is smaller on the drive
coupling. The bigside needs to be shaved down .5mm. Or it would be easier to hollow the
drum side out. Anyway, not having a dremel or a drill handy we knocked the end out of the
old drum and new drum and swapped the ends so the drive coupling would fit.
Yeah we scratched the drum in the process, I ordered the drive coupling.
I'm tempted to try and swap the ends again, but only if Precision eats the drum if it fails.
And it is out of toner. I'll bet it's keyed different also.


DR

[Desert Rat]

Light streak

I got the PM done. I was unable to dremel the drive out, so I replace the drive hub without scratching the drum.
I did the adjustments in the order the book pointed out. The adjustments for the developer were the same as
for the drum. Should I have done them twice? The copy came out ok but there is a lite streak that runs from the
back to the front on the trail edge I believe. The edges were still alittle dirty on the 2nd side mode, but seemed
to go away after cleaning the duplex paper path.?The light streak is most noticible when making a dark copy,
has anyone seen this symptom?

Thanks

DR

[CraigW]

If you are doing drum & dev you do drum column, PM with only kit & dev change = developer column.

I would try cleaning the write unit dust cover above the drum carriage, Check the T/S corona. And take a look at the bristle on the developing unit. concerning the light area (assuming it's L->T)

[Desert Rat]

CraigW,
I think I understand. "PM with kit and Dev change = dev column". This would be the in between
PM when only the dev gets replaced along with items in the PM kit.

"(assuming it's L->T)" I do not understand this. Looking at the dv brush to make sure it is even
I can do. Is there something I'm missing there?
I will look for the write unit dust cover above the drum carriage.
I used the voltage reading from the previous drum. (Don't know why I did.) Could that make
that light streak?

DR

[CraigW]

These machines get kit and new dev every PM, And new drum every other PM. Don't forget the parts counters as well.

L->T = Lead to Trail direction of fault.

Write unit filter glass in long thin cut-out above the drum.

Charge grid manual adj not likely to cause light area. If oem drum it will have it's own voltage on gear end.

[Desert Rat]

No this is not a lead to trail edge light streak. It is located an inch inside the trail edge and is accross
the paper travel. (crosstrack = across the paper travel direction) Front of machine to back of machine.
Top to bottom. It did not show when I ran a gray target, it actually looked good for a half tone.
But darken it up and the light streak will show.

Thanks for your time

DR

[CraigW]

^^^ That one might be a little tough.