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chriscctx
04-22-2011, 06:56 PM
konica minolta c450 is only printing in black, no color. Came on suddenly. All color tests will just print black. All color printing ceased at the same time.

Any ideas?

jamesmutz
04-22-2011, 07:11 PM
When you say printing black on the colour test print, do you mean it is only the black portion of the print that is printing or that it is printing the entire test print in black? It could be the transfer pressure/retraction as the black IU is always in contact with the belt but the colours only engage when needed. As a basic step, these machines seem to do strange things occasionally when it comes to colour but a good turn off/on usually fixes them.

JustManuals
04-22-2011, 10:08 PM
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chriscctx
04-23-2011, 03:12 AM
It's only printing the black portion of the test. I have several color tests I run some of which are files of my own. When they are ran, only the black areas of the tests are printed - the other areas that are to be in color do not print.

The reason I find this strange is that is was working fine according to the printed copies I saw just hours before.

bizhub1
04-23-2011, 04:31 AM
I would check transfer belt assy, see if the color rollers are moving properly

ddude
04-23-2011, 05:13 AM
I would check transfer belt assy, see if the color rollers are moving properly

Agree- I think that the transfer belt moves up against the color IUs when a color copy is requested, it would appear that your transfer belt is not contacting the color IUs

chriscctx
04-23-2011, 05:19 AM
And that would happen all at once with all three CMY iu's?

ddude
04-23-2011, 06:30 AM
Yes, because I believe that the CMYs are working, the belt just isn't contacting them. iirc, the belt is always set for black, but needs to come up to position for any (and all) color copying.

chriscctx
04-23-2011, 07:28 PM
replaced the transfer belt - no change

chriscctx
04-23-2011, 07:33 PM
I am getting a p6, p7 and p8 error code - which are cmy imaging unit failures but can not find out why

minimerlin
04-24-2011, 11:49 AM
I am getting a p6, p7 and p8 error code - which are cmy imaging unit failures but can not find out whyBecause the IDC sensors do not see anything on the transfer belt...because it is not getting primary transfer from the IUs!

Take out the belt and make sure that the rollers move correctly when you operate the cam gear.

kan
04-24-2011, 06:05 PM
Have you tried half tone test pattern (set to 100) for each of the color in test mode? If you have not, test 8.5 X 11 paper (landscape) and see if the paper is completely blank or you do see some traces of color you are testing. Check for all CMY
Next remove the image unit and look from the top (drum side up) and look for the mag roller through the myler and see if there is any starter brush on the roller.

chriscctx
04-25-2011, 05:47 PM
The only thing that prints is black - all color tests produce blank white pages. To recap - the transfer belt has been changed with no difference. I think its safe to safe its not the transfer belt. This situation came on suddenly, it was not a problem that got worse over time. Could it be a bad motor? (Just thinking outside the box). Imaging units appear to be good and have even swapped a few of them out with no difference.

bizhub1
04-25-2011, 09:27 PM
Not by a manual now but see if you can turn on the retaction motor in service mode, it sure sounds like the color rollers in the belt are not moving towards drums

chriscctx
04-25-2011, 10:18 PM
how do I turn it on from service mode?

bizhub1
04-26-2011, 03:17 AM
sorry I mis spoke, you have to go in service mode and check the retraction sensor, not the motor

copytechman
04-26-2011, 12:51 PM
According to the book, if the retraction/engagement mechanism wasn't moving properly you'd be getting C2152 codes all over the place. Its the code that box throws when the retraction sensor doesnt get triggered in a timely manner. Not to say something else isn't broken tho and allowing the "mechanism" and sensor to work properly but no actual engagement of the 3 colour 1st transfer rollers. (assumes alot!)

Regards! A

Edit: also running say 20 black copies then 20 full colour copies (not auto colour) and back and forth like that will force the machine to engage/retract colour transfer rollers. If you don't get any c2152 codes after doing that a bunch of times then IMHO its pretty safe to say the retraction sensor (and associated mechanisms) are indeed working and you MAY have a different issue.

chriscctx
04-26-2011, 05:01 PM
I'm thinking a motor is out or not running. All image units have been swapped out. 3 different transfer belts have been put in. All with the same issue of not printing color.

copytechman
04-27-2011, 02:03 AM
Again according to the book there are c-codes for drum and dev drive motors on that model, however a quick inspection of the book leaves me to wonder if you have an led head failure of some sort since I didnt on quick inspection find any sort of failure codes for them. Possibly a faulty icp or something that controls the 3 colour led heads? I don't know for sure but if the machines only throwing P-codes and no C-codes then I'd maybe start there somehow.

Regards!
A.

bizhub1
04-27-2011, 04:43 AM
Again according to the book there are c-codes for drum and dev drive motors on that model, however a quick inspection of the book leaves me to wonder if you have an led head failure of some sort since I didnt on quick inspection find any sort of failure codes for them. Possibly a faulty icp or something that controls the 3 colour led heads? I don't know for sure but if the machines only throwing P-codes and no C-codes then I'd maybe start there somehow.

Regards!
A.

Yes I agree totally with the codes, I would make sure all the drive linkages to the belt unit are fine also.

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