View Full Version : bizhub C360 flips corners and paper skew, intermittently.

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10-30-2012, 02:11 AM
I think I've finally got it figured out, so this really qualifies as a heads-up thread. Of course I thought the same thing the other five visits ... forgive me if I draw out the story.

It all starts with a truckload of Comet brand letter sized 20# bond paper. What do you suppose would happen if the paper manufacturer, instead of cutting it the official 279.4mm got carried away, and cut each ream at 280.1mm? Just 0.7mm larger than standard. In most cases nothing extraordinary happens. But if you load this slightly oversized paper into an LCT with stationary guides it fits snuggly enough that the paper drags against the sides, and when the tray gets down to the last 250 sheets of paper the lift plate tips, and it jams nearly every time J20-21. On a couple dozen paper decks I've loosened the screws and taking up the clearance in the mounting holes, I've spread the front and rear frames an additional 0.5mm. Doesn't sound like much, but it's enough. But it's not about that.

This one is flipping corners, specifically the leading edge rear, flipping back before imaging. Letter size only, letter is in the PC-408 paper deck, tray #3. Seems simple enough right? Maybe 16" of vertical paper path to examine, from tray #3 to the primary transfer belt. For the last two weeks I've been adjusting LCT frames, so why not? Sooner or later it will start here too. Maybe its a related symptom? Many multiple copies, no flipped corners.

Second visit I thought maybe an extra mylar or two might help, so I bridged the gap between the lower and upper doors. Also added a couple of mylars to the outer side of the door. Many multiple copies, no flipped corners.

Third visit I got to looking more closely at the deck lift mechanism. It was ~4mm low at the rear, and the stack just barely clears the frame at the leading edge. So I level up the deck with some strategic re-forming, and trim 2mm off the flag on the pickup roller assy. Now the stack is level and 2mm higher. Many multiple copies ...

Fourth visit the office manager suggests trying some different paper. Why not? I'm running out of hair to pull on. This time I actually see some flipped corners with both the new and old paper, especially when running the second side. There's got to be be a clue there, but I can put my finger on it. After a while it stops flipping corners, and I'm out of time.

Fifth visit I think maybe 2mm off the flag was not enough, let's try 4mm. I check every guide surface, every mylar, not a scratch not a paper cut anywhere. One or two flipped corners, but the last 200 consecutive were flip-free. Maybe fixed?

Nope. Sixth visit. There is finally a break in my tunnel vision. I wonder what would happen if you loaded this same paper in all the trays? They all flip from all three trays! Finally I can forget about tray #3. I disassemble the registration assembly and clean. There is nothing significant there,
only the slightest wear on the rubber roller at the paper edge width. Hardly measurable. Above that is the secondary transfer assembly. Not much to go wrong here, of course it's spring loaded. I can check that. When I touch the transfer guide it goes "click". The white plastic latch was unlatched at the rear. Remember the little warning tag at setup?

Can you believe it could that simple? I know what I'll check first if I see another flipped corner. =^..^=

10-30-2012, 03:19 PM
Ah yes......make sure to pull out all yellow plastic from shipping clips.

10-31-2012, 02:04 AM
Ah yes......make sure to pull out all yellow plastic from shipping clips.

It fails Stabilization and Gradation if you leave those in. Also light prints with cool 3mm stars. Done that. =^..^=

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