bizhub 284 thick card copy quality issue

[macuk]

I have a customer with a 284 which when running card (thick 1 to 4), gets mis-registration towards the rear edge. Another engineer recently changed the fuser and the transfer belt for other problems not related to this issue. Not very experienced on these machines. See the attached images. Can anyone give me any advice on how to fix this! Thanks

[blackcat4866]

It doesn't appear to be paper registration, regardless of whether it's thick or plain paper. It look to me like the black color registration is out. Have you done the stabilization and gradation yet? =^..^=

[macuk]

Sorry about the pdfs, the customer was using grey card. I have done a stabilisation and gradation. This only happens on heavy settings and the registration is off on the rear third / quarter of the copies only. the crop marks on the first image seem to show the colours are all slightly off with each other with the black being the worst.

[JR2ALTA]

Very often when replacing fuser you'll encounter registration issues, go to service and machine and adjust fuser speed and or loop

[occus]

I had the same issue on a c284e...

Try to:
1. Laser skew reset
2. Image stabilisation and initalitation 2x!
3. Gradation Adjust and scan the pattern 3times for printer and 3times for copy
4. Restart
5. Test

I dont' think it comes from Fuser

[macuk]

Thanks for your suggestions. I have tried adjusting fuser speed in increments up to +15 and down to-15 with no joy and have adjusted loop for heavy paper as well. I have stabilised and initialised 4 or 5 times and auto grad adjusted but have not yet adjusted laser skew.
I am trying to get my head around this. if it was fuser speed difference then wouldn't it cause a band rather than mis reg? How will laser skew adjust help?
The image is fine on plain paper and the first part of heavy paper. The colours are only mis registering towards the rear edge of the copy
If the image at the start of the copy is in registration but not at the last third / quarter then is it down to varying speed of the transfer belt? Just trying to look at this thing logically. If anyone can help further i would really appreciate it

[allan]

Go to Machine -> service mode -> machine -> Trail edge color reg adj

[darry1322]

In some machines there is a loop sensor to adjust paper loop between transfer and the fuser entrance.

Remember, during transfer the toner colors are layer onto each other. If the fuser pulls faster than transfer, the layers are pulled off unevenly causing a color shift at the trail edge.

The loop sensor adjusts fuser speed depending on the amount of loop at a given moment.