C6501 - Blurry Text (Misregistered)

[resolute]

I am battling a problem that has persisted for over 2 months now. We have a misregistration that is causing blurry text and seems to be mostly in the magenta. For example if I try to print blue text (100/70/0/0) the text will be fine in some places on the sheet - but blurry in other places - sort of looks like a magenta drop shadow. I looks to be about 2 pixels off. The technicians have replaced lasers, belts but have made no progress in resolving the problem. They are thinking about changing the main image control board - but are trying to explore other options as this is a rather expensive part.

I am hoping that someone else has had this problem and found a solution. We have not changed stock in the 2 years that we have had the machine... and until 2 months ago, did not have this problem.

Any advise or suggestions greatly appreciated.

[pinoyprinter]

pls interchange the transfer rollers (CMY) inside transfer belt. if not try to replace color registration unit, and if not try firmware update.

[empiru]

After conducting the Auto Color Registration Adjustment, what kind of values do you get for Magenta, in that Table?
It is possible, that the Transfer Belt is not installed correctly. Be careful: on the bottom of the transfer belt, there is a roller with a white plastic guide on each end. The Belt must fit almost perfectly into those guides.
I read that you have changed the belt, but it can be possible that it was installed the wrong way several times.
If this is not the case, I suggest you replace the Color Registration Assy - like pinoprinter said. It is located to the left of the Transfer Belt, as it is mounted in the machine and has 3 sensors that determine wether the colors are aligned or not.
I hope this helps!

[seniortech]

After running Auto Color registration did you run the Manual color Registration adjustment?

[jhbtech]

I have had the same problem but mine also shows a bit of yellow as well.i have changed laser units,transfer belt unit,color reg unit,and reg roller unit.my problem started a year ago and is most prevelent on 300gsm.if u have any solutions please post on this site.

[empiru]

Ok, excuse me if I'm going to ask an obvious and stupid question... but... did you run all the adjustments in the manual when you changed a part?
Again, I know this is, in the copier world, like common sense... but did you?

[jhbtech]

Yes I have.I get 000.0 values when I do auto color reg.I hve gone further by changing the pulse disc on tranfer belt drive and also swopped drum drive units but I still have a solution

[empiru]

Ok, that's obviously a BIG problem - I've never seen a C6500 do that... This is very interesting for me, so I'll "dig" a little deeper and try to help you out.
I like them challenges

[resolute]

A asked the tech about a manual color registration adjustment. - and got told it doesn't work. So they only do the auto color adjust. Can u provide me the instructions on how to do the manual adjust... Thanks

[empiru]

Ok, that's a tough one. I mean, I provide service for 3 years now (I'm not saying it's a lot of time, I'm just trying to make a point); after my first year, I did a Manual Color Registration on a Bizhub Pro C500. It took me about 1 and a half hours and my result? I managed to completly "destroy" the machine. A far more experienced technician came the other day and spent about 4-5 hours to fix it...

So, please don't get me wrong, but my instinct tells me, I should help you, by not telling you how to do it; it is very possible that your text will become more blurry after you do the manual adjustment, depending on your skills and level of experience.

HOWEVER, with that in mind, if you are 100% sure you want to do this do these steps in the first place:

1. Enter Service Menu.
2. Go to Test Mode.
3. Go to Test Pattern Output Mode
4. Set the values for ALL colors (CMYK) to 255.
5. Press return.
6. Go to Machine Adjustment -> Printer Adjustment -> Auto Color Registration; conduct it.
7. Go back to the Printer Adjustment -> Manual Color Registration.
8. Press the COPY button on the top left of your touchscreen.
9. Select A3 or 11x17 in paper - I suggest you put ~100 gsm paper -.
10. Select FULL COLOR.
11. Press the START button.
12. The machine should put out an A3 or 11x17 with some lines and crossmarks - black and CMY. Take the paper and put it on the scanning glass, face down. On it, put 5-6 sheets of the same paper type - white, of course.
13. Close the DF or whatever you got on the machine.
14. Press the SERVICE button on the top right of the machine.
15. Press SCAN or START (frankly, I don't remember exactly what button comes up on that screen).
16. The machine will scan the paper and modify the values you have on the table on the screen - corresponding to every value there will be an OK or NG.
17. Take a photo of that screen and attach it to a following post so that I can tell you what to do from that point further.
18. Exit Service Mode.

Hopefully, your machine isn't very screwed up. We will see when you post the picture.

Good Luck!

[resolute]

Empiru -- Attached is a screen shot as requested...IMG_0190.jpg

[empiru]

Ok, great!

We are now starting the hard part of the adjustment. First, you have to open the toner supply unit. There, you will find, corresponding to every color (CMY) a plate, fixed with 2 screws. For Magenta, ONLY, you have to move up or down that plate (be careful, that mechanism is very sensitive - a notch of that plate changes the position of the image by 0,5 pixels). Now, you do the steps I told you all over again, starting with the Auto Color Registration and ending with the scanning of the A3 or 11x17 sheet of paper, until OK is displayed everywhere for Magenta.
Again, I'm telling you, be very careful and very patient, this may take a while to adjust. Or if you are lucky, it could take only 5-10 minutes.
I hope this helps. I'll be here for any other questions!

[empiru]

Oh, I forgot to tell you this: after every cycle of adjustments, try to print something that was blurry before to see if it's gotten better or worse;
I'm just saying this, because there are misalignments that the human eye can't see.. but the scanner does..

[resolute]

thanks- i will try that tomorrow - and get back to you.

[empiru]

Resolute,

Did you try the Manual Adjustment? If yes, did it work?