View Full Version : Bizhub shrink / distortion on transfer belt

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07-04-2015, 01:12 AM
Been working on this Bizhub c452 for awhile. The image on the transfer belt is shrunk on the horizontal and one side is shrunk more than the other. If we open the right door and look at the image while it's still on the transfer belt, the left side of the image is shorter than the right. We have replaced the transfer belt and the print head laser. Can anyone tell me what else would cause an image to be distorted on the transfer belt?

Thank you all so much.

07-04-2015, 01:15 AM
All bizhubs in general ... or a specific one? A model number might help. =^..^=

07-04-2015, 01:38 AM
I'm sorry. It is a Bizhub C452. I'll edit the original post to reflect it.

07-04-2015, 01:50 AM
Which direct is horizontal?

main scan/sub-scan

Are the colors registering properly? If yes, you can rule out the laser.
Does the transfer belt seat correctly atop the IU's? Higher at the front or rear? Are you getting good primary transfer and developing of the image.

If you have already changed the transfer belt and laser unit, perhaps it's an image processing issue?

Pictures might help. =^..^=

07-04-2015, 04:45 PM
Color lines up perfectly in relation to black. The main scan is true, it is only the sub-scan that distorts. The problem occurs on copies, prints, and internal diagnostic prints which rules out the possibility of it being a driver issue. Using [Machine] → [Printer Area] → [Paper Feed Direction Adj.] I can pull the image back out to the proper length on one side by increasing the setting to 4. However, this does not remove the problem with the one side slowly getting shorter than the other. So when we do the grid test print from Paper Feed Direction Adj. the bottom right corner of the print is shorter by 1.5 to 2 mm. Just looking at the image it looks fine. But this machine is being used to make booklets, so when folded and saddle stitched, the pages are all crooked and the duplex just reverses the printing direction which doubles the problem.

The transfer belt slides in smoothly. The retaining clips fully engage. On the top of the transfer belt it might be a little closer to the frame on the right side than the left, but it's so minor that it could be my imagination. I will get the high res camera out to see.

07-04-2015, 04:51 PM
Check the zoom settings in maintenance mode

07-04-2015, 06:00 PM
Could the laser assembly be seated a little crooked, or the frame tweaked? That's all that I can think of. =^..^=

07-06-2015, 05:00 PM
this is not a production print unit and image perfection was never striven for. a grid pattern will never be exact nor will a 2nd sided print land exactly over the first side. sorry to burst your bubble.

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