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nyclad
05-11-2017, 09:35 PM
Hi guys,


On my Bizhub C450, I'm getting a pattern of vertical lines on the bottom third of thick stock, regardless of color.

I printed out a test pattern in service mode.

36579
The bottom of this 11x17 page (80# cover) is the last part of the paper out of the machine (trailing side.) The counter top tiles are 4 inches, for reference.
The pattern looks like some sort of comb or guide, but I can't seem to find it. I removed the fuser and inspected/cleaned the separator fingers, but I don't think that's it.
Plus there seems to be a set of horizontal smudges, like a roller slipping or something.

Any ideas?

I don't see it on thinner stock, like #20 text. Maybe the thicker paper is refusing to go smoothly through the paper path somehow? But this machine is rated for 100# cover or 256 gsm paper.
Plus to doesn't seem to explain why the smudges/lines are on the lower half of the paper (trailing edge.)

Thanks in advance.
Steve

blackcat4866
05-11-2017, 10:49 PM
Do the marks line up with any star-wheels, perchance, before or after the fuser? If it does this will be how you define the heaviest printable media. =^..^=

nyclad
05-11-2017, 11:11 PM
In looking at both the field service manuals and a visual inspection, I don't see anything before the fuser that would cause this, which is what confuses me. I don't see how these marks can be made after the fusing happens.

The only thing that resembles star rollers is the exit section, and they don't seem to line up with the marks on the paper.
36584

blackcat4866
05-11-2017, 11:23 PM
Something like this?:

3658536586

The toner does not fuse instantly when passing through the fuser. Anything that contacts the paper immediately before or immediately after can cause tracks in your image (includes fuser claws, star wheels, and exit rollers). And usually there is nothing that you can do about it .. except using lighter media. =^..^=

Synthohol
05-12-2017, 12:08 AM
as with most CQ issues, stop the copy at different times and see when the scratches are created.
is the tray you are using set to the proper thick 3 or 4?
the scratches look like the ribs on the exit guide plate to me. does it have a finisher?
try disconnecting the finisher and see if still occurs, its possible the "bridge" unit is pulling faster than the paper is exiting the fuser minimizing the loop so it scratches the guide plate.

nyclad
06-14-2017, 08:58 PM
I know it's been a while since my last post. But I'm optimistic I found the issue.

There is an electronic registration clutch on the paper transfer section I think might be skipping a little, causing the paper to ram a little into a guide that leads to the fuser. This clutch drives a roller on the paper path.

I removed the clutch, sprayed it down with contact electrical cleaner (forcing spray inside too) and some dark liquid did come out, so I hope that was various gunk or whatever was jamming the clutch down. I was unable to open the housing on the clutch, so I simply applied the spray liberally, and waited a few days for it to evaporate out, rotating it in the process, just to make sure.

It is slightly better when I replaced the cleaned clutch, but around the same spot where the lines showed up, there's a slight smudge still, which means there is a slight hiccup on the clutch, but nowhere as near as bad as before, but not exactly print quality. I'm thinking I'm going to try replacing the clutch.

My only hesitance is that the new replacement clutches look slightly different.

Here's a photo of the clutch on the right side door. With a red arrow pointing to the location.
36881

Here's the location of the clutch in question and the part number.
36877


And the guide that the paper gets rammed into, causing the marks (this makes sense as I can see loose toner on the grooves of the guide, and it's before the fuser.)
36878


And what the clutch looks like:
36879 36880


The clutch part number is 9322-1400-11. The issue is that I can't seem to find it anywhere. It lists at $115! But nobody has them in stock. Does anybody know a cheaper source that's in stock, or failing that, an alternate? I notice a part 9322-1500-11 which appears similar, but I'm not sure if it is the same dimensions or specs. Or does anybody know how to open the clutch so I can clean or potentially rebuild it? Any ideas? Thanks in advance.

Synthohol
06-14-2017, 11:52 PM
carefully remove the star clasp and pull apart. use emery cloth to resurface the plates, clean with IPA and reassemble.

http://www.copytechnet.com/forums/attachment.php?attachmentid=36883&d=1497477395

Albonline
06-15-2017, 02:02 PM
check the sensor under the fuser. loop sensor i think its called.

copier addict
06-15-2017, 05:32 PM
carefully remove the star clasp and pull apart. use emery cloth to resurface the plates, clean with IPA and reassemble.

http://www.copytechnet.com/forums/attachments/konica-minolta/36883d1497477395-bizhub-c450-vertical-lines-print-thick-stock-20170614_175935_resized-jpg

The registration clutch on a C450 does not come apart. If cleaning from the outside doesn't work it needs to be replaced.

Synthohol
06-16-2017, 12:00 AM
this may sound off the wall but it can work...
remove the clutch, soak whole clutch in coca cola for an hour. the phosphoric acid in the soda will loosen or remove corrosion. (works fantastic on battery terminals and radiators) rinse thoroughly with water then soak in alcohol to remove any water. use compressed air to dry or just reinstall.
when you have nothing to lose you have everything to gain.

nyclad
06-16-2017, 08:32 PM
Synthohol,

True, if I have nothing to lose...I might as well grab me a soft drink...:)



this may sound off the wall but it can work...
remove the clutch, soak whole clutch in coca cola for an hour. the phosphoric acid in the soda will loosen or remove corrosion. (works fantastic on battery terminals and radiators) rinse thoroughly with water then soak in alcohol to remove any water. use compressed air to dry or just reinstall.
when you have nothing to lose you have everything to gain.

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