[CQ] Registration Problem

[33CRP]

I have a Konica Minolta BizHub C450 that has developed a color registration problem. Most noticeable on color type. The first sheet printed is in register. The next sheets are not but it's 1/2 the sheet. As in running 8.5" x 11 2up, the first 8.5" x 11 is out of register and the second 8.5" x 11 is in. I've replaced everything, IU's, transfer belt & transfer roller but still have problem. Went into service mode and did the registration adjust. I've cleaned all the heads (LPH's etc) with alcohol but nothing is helping. Has anyone seen this problem before or knows what's causing it?
Thanks

[fixthecopier]

Re: Registration Problem

I would think the reg clutch is slipping. Change it.

[33CRP]

Re: Registration Problem

Are you talking about the clutch on the paper transport section where the transfer roller is attached?
Thanks

[fixthecopier]

Re: Registration Problem

That's the one.

[33CRP]

Re: Registration Problem

OK Thanks, I give that a try.

[33CRP]

Re: Registration Problem

Replaced the paper transport clutch but that didn't fix the problem. Still out of register.
Could it be the loop sensor that's located before the fuser?

[Synaux]

Re: Registration Problem

Replaced the paper transport clutch but that didn't fix the problem. Still out of register.
Could it be the loop sensor that's located before the fuser?

I would at least inspect the loop sensor if not try replacing it and also clean the IDC sensors below the tranf belt.

Also, does this happen with internal test prints too?

[allan]

Re: Registration Problem

Mmm P-21 could be dirty idc sensors. Color registration not image registration.

[33CRP]

Re: Registration Problem

Thanks for the reply's.

Here is a more accurate description of whats happening. The very first 11 x 17 that come out of the press is in register but then the next sheets that continuously feed, the first half of the page is out of register and the second half is good. This happens when feeding out of both the tray or bypass. (The bypass on the MGI, see below, is actually a press feed that continuously feeds one sheet at a time.) It appear to be the magenta that moves. If the press hesitates between sheets fed, for example to stabilize or a feed issue, when it restarts printing the first sheet is in register again and the rest are not good as stated above.Also when running 8.5" x 11" out of the large capacity tray, which comes out landscape, they all seem to print fine.

My problem is that I can't find anyone willing work on this machine. This Konica Minolta Bizhub C450 is the print engine on my MGI DP40 digital press. Because MGI is on their 5 generation (they'd love to sell me their new XL8700 at $400,000) they no longer have people to work on this machine. I've contacted KM and independents but no takers. So I have been doing all the repairs myself. Even pulling out the LPH chassis to replace the black LPH.

Any help would be GREATLY appreciated!
Thanks
Gary

[fixthecopier]

Re: Registration Problem

Although this is not your issue, I noticed you said it was doing it on 11x17. I had a 550 that would wrinkle only 11x17. It was a paper dust build up on the reg roller. It was causing it to slip a little in the center of the page as it tried to grab it. The reg roller can be cleaned with alcohol.

[EarthKmTech]

Re: Registration Problem

Off topic, but C451/550 & 650 practically all wrinkled A3 & what ever you imperial equivalent is in the centre towards the end of the page out of the box. You simply increase the printer registration loop for trays 1 & 2 by +3. Will disappear instantly.

Regarding the C450 color reg drift, it sounds exactly like the fusing loop sensor is sticking, on modern machines, even upto the current C754e they still have the same issue, but on those it can also be a defective black drum encoder necessitating replacement of the entire main drive unit and they dont always display a P code. Been there done that, it aint pretty.

[copier tech]

Re: Registration Problem

Have you updated the firmware, there is a special FW for registration issues.

[allan]

Re: Registration Problem

Off topic, but C451/550 & 650 practically all wrinkled A3 & what ever you imperial equivalent is in the centre towards the end of the page out of the box. You simply increase the printer registration loop for trays 1 & 2 by +3. Will disappear instantly.

Regarding the C450 color reg drift, it sounds exactly like the fusing loop sensor is sticking, on modern machines, even upto the current C754e they still have the same issue, but on those it can also be a defective black drum encoder necessitating replacement of the entire main drive unit and they dont always display a P code. Been there done that, it aint pretty.

If the drums are the same diameter there is no need for a drum encoder. The registration is done with exposure timing. I get that encoder issue with C451's with the bigger black drum and i normally get P-14 and P-21 at the same time. If you want to frustrate yourself try to do manual registration in that condition.

[33CRP]

Re: Registration Problem

Thanks for the reply's. No P codes have shown up. I've ordered a new loop sensor and pawl and should have it by weeks end. I'm hoping that's where the problem is coming from. To take out the PWB box just for a look see is a bigger job than I'd like to get into unless I know for sure that that is the problem. And as far as firmware. MGI's own software is incorporated into the KM C450 firmware so we can't make any upgrades without screwing up the operation of the press.

[Synaux]

Re: Registration Problem

Thanks for the reply's. No P codes have shown up. I've ordered a new loop sensor and pawl and should have it by weeks end. I'm hoping that's where the problem is coming from. To take out the PWB box just for a look see is a bigger job than I'd like to get into unless I know for sure that that is the problem. And as far as firmware. MGI's own software is incorporated into the KM C450 firmware so we can't make any upgrades without screwing up the operation of the press.

Are you sure? MGI may be using their own software for their peripherals and using KM's firmware to run the engine. Either way, I would contact MGI for legacy firmware updates--they should be willing to accommodate.
Are you looking at "warnings" in service mode for P Codes?