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33CRP
01-12-2015, 10:00 PM
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
01-12-2015, 10:50 PM
I would think the reg clutch is slipping. Change it.

33CRP
01-12-2015, 11:18 PM
Are you talking about the clutch on the paper transport section where the transfer roller is attached?
Thanks

fixthecopier
01-12-2015, 11:37 PM
That's the one.

33CRP
01-12-2015, 11:58 PM
OK Thanks, I give that a try.

33CRP
01-17-2015, 05:12 PM
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
01-17-2015, 06:37 PM
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
01-17-2015, 06:45 PM
Mmm P-21 could be dirty idc sensors. Color registration not image registration.

33CRP
01-17-2015, 07:20 PM
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
01-18-2015, 03:03 AM
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
01-18-2015, 12:17 PM
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
01-18-2015, 02:47 PM
Have you updated the firmware, there is a special FW for registration issues.

allan
01-18-2015, 03:00 PM
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
01-18-2015, 11:30 PM
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
01-19-2015, 04:31 PM
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?

33CRP
01-19-2015, 05:47 PM
MGI incorporates their own software into the firmware. So through a computers "MGI Pilot" application you can manually adjust the C450's THV and the fuser temperature as well as the press feed speed. You can run just about anything through the machine. Including vinyl, teslin, PVC paper and even metallic stock. I haven't seen any P code popping up. If there is a way of bringing up the past history of error codes, that is something I'm not aware of. In addition we've been doing a lot of testing with various stock weights and sizes. It seems that registration problem is mostly limited to the 11" x 17" size in any stock weight. Perhaps the feed rollers in the paper transport are worn but the seem OK.

hotfuser
01-19-2015, 06:11 PM
MGI incorporates their own software into the firmware. So through a computers "MGI Pilot" application you can manually adjust the C450's THV and the fuser temperature as well as the press feed speed. You can run just about anything through the machine. Including vinyl, teslin, PVC paper and even metallic stock. I haven't seen any P code popping up. If there is a way of bringing up the past history of error codes, that is something I'm not aware of. In addition we've been doing a lot of testing with various stock weights and sizes. It seems that registration problem is mostly limited to the 11" x 17" size in any stock weight. Perhaps the feed rollers in the paper transport are worn but the seem OK.

Have you checked the fuser speed.

SOLUTION: To adjust the fuser speed,perform the following:
1.EnterTech Rep mode.
2. Select Machine.
3. Select Fusing Transport Speed.
4. Adjust the settings/data as needed.

I may have missed this throughout this post but i thought id post it just in case.

33CRP
01-19-2015, 06:34 PM
yes did the the fuser speed and loop adjustments. No improvements.

Synaux
01-19-2015, 07:05 PM
MGI incorporates their own software into the firmware. So through a computers "MGI Pilot" application you can manually adjust the C450's THV and the fuser temperature as well as the press feed speed. You can run just about anything through the machine. Including vinyl, teslin, PVC paper and even metallic stock. I haven't seen any P code popping up. If there is a way of bringing up the past history of error codes, that is something I'm not aware of. In addition we've been doing a lot of testing with various stock weights and sizes. It seems that registration problem is mostly limited to the 11" x 17" size in any stock weight. Perhaps the feed rollers in the paper transport are worn but the seem OK.

Are you able to get into the Service Mode to check the counter for warnings??

33CRP
01-19-2015, 08:51 PM
Found the warning counter. Here are some numbers. I never cleared them out (if that's possible to do) so I don't know how long they've been there.
P-5 - 34
P-28 - 8
P-6, 7, 8, 9, 22, 29, 26 & 31 - 0
P-21 -15
P-27 - 5
When I get a P-5 code I clean the front sensors PC8 & PC9 and that clears it out.
Usually get that when running heavy solids.

DelawareJim
01-20-2015, 04:11 AM
I've worked on a couple of the C450's and a ton of the C350's. Question: of the 11 x 17 copies that have the registration problem, does the problem start / stop at the exact same point or does it vary and appear random? If it varies I feel the cause would be something mechanical. Maybe try a new Magenta Image Unit, maybe run some copies and put your fingers on the front of the Magenta Image Unit and feel if there may be bumping or hesitation, maybe it's a problem with the Magenta drive assembly. If its exactly the same on every copy (except the first copy per your description) then that may be a software issue. In that case, I would try a simple trouble reset (holding the utility/counter button down while you turn on the copier, touch "trouble reset" when you see it on the display panel and then cycle copier off and on. As a last resort I would attempt a memory/data clear. Hey, it was making good copies before, something changed to give you this new issue. Keep us informed, you have an interesting problem.

33CRP
01-20-2015, 06:17 PM
Hi DelawareJim, Except for the 1st print, all the following are out of register in exactly the same place. It's not random. I was told by MGI to try and set the paper size off a little bit. I set the RIP and press to sheet size 11 x 17 1/16. Ran and no change. Then I did the trouble reset as you suggested and it actually register much better. I could have used what came out of the press. Not perfect but much better then I had gotten previous to the reset. Then my assistant decided to set the size back to 11 x 17 and guess what...it was out of register again. I tried to do another trouble reset but it wouldn't come up on the screen. MGI (though has no clue of what's going on) thinks it could be the drive section too but as you said I'd think it would be a random problem. Plus to take apart the PWB box to get to the drive section seems a daunting task. He also said it could be that the drum encoder is dirty or faulty but I didn't think the C450 has a drum encoder, can't find one in the parts manual. I'm completely stumped. I don't know if I screwed up some setting with all the service mode probing I've done. I played with the color ranking to see if that changed anything, loop adjust, fuser speed etc. Nothing effects the registration.

Synaux
01-22-2015, 08:57 PM
Did you get a chance to change that Fuser Loop Sensor?

Also, clear all those P Warnings and see if any come back up.

I would contact MGI again if I were you. They should supply you with legacy firmware seeing how they do not support it any longer. The fact that you could not get the Trouble Reset to work again makes me suspect firmware or possibly a board/memory issue....

33CRP
01-24-2015, 12:56 AM
I'm still waiting for the Fuser Loop Sensor.
Should have it end of next week
I cleared the P warnings and nothing new came up.

As far as MGI, I did contact them regarding the issue again. To give you of an idea of what it's like to deal with MGI. I paid the $150 for the 1 hour of phone support. Got the "field engineer" on the phone and his 1st question to me was " how do you get into service mode? I'm not familiar with that machine." Wow if that doesn't give you confidence.

We found running 12 x 18 instead of 11 x 17 actually has a little better registration. Not perfect but was still able to get some jobs out. If I play with the loop resist setting and increase the 165/mm the registration seems to get a little better but then we get a lot of jamming. So we have to back it up again. I'm hoping the Fuser Loop Sensor is the problem.

Synaux
01-27-2015, 06:47 PM
I'm still waiting for the Fuser Loop Sensor.
Should have it end of next week
I cleared the P warnings and nothing new came up.

As far as MGI, I did contact them regarding the issue again. To give you of an idea of what it's like to deal with MGI. I paid the $150 for the 1 hour of phone support. Got the "field engineer" on the phone and his 1st question to me was " how do you get into service mode? I'm not familiar with that machine." Wow if that doesn't give you confidence.

We found running 12 x 18 instead of 11 x 17 actually has a little better registration. Not perfect but was still able to get some jobs out. If I play with the loop resist setting and increase the 165/mm the registration seems to get a little better but then we get a lot of jamming. So we have to back it up again. I'm hoping the Fuser Loop Sensor is the problem.

Ouch. Were you able to ask MGI about them supplying firmware?
Hopefully that sensor will help--let us know

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