MPC4500 Color balancing

[Zia Graphy]

Hi there,

I've got an MPC4500 that is incorrectly mixing colors. If I print an internal test pattern (SP 1103-002) the CMYK part of the chart looks pretty good to my eye, however I've never been great at distinguishing what are the perfect levels of density throughout the chart. But the Red, Green, Blue is definitely off. The Green is most noticeably the worst, being strongly skewed towards the blue/aqua end of the spectrum, suggesting that there is too much cyan and not enough yellow.

I've tried running an Auto Color Calibration, however it consistently fails.

Any ideas on what could cause an Auto Color Calibration to fail each time and how to fix that. Or does anyone know a workaround for manually adjusting the color balance? I'm aware of the user feature under the "edit/color" tab which allows the user to adjust the colors via a color wheel. Adjusting green to the yellow end of the wheel actually corrects the problem for copying, however I'd like something more permanent and that would also work for prints.

Thanks for any help!

[ucinn]

Re: MPC4500 Color balancing

Hi there,

I've got an MPC4500 that is incorrectly mixing colors. If I print an internal test pattern (SP 1103-002) the CMYK part of the chart looks pretty good to my eye, however I've never been great at distinguishing what are the perfect levels of density throughout the chart. But the Red, Green, Blue is definitely off. The Green is most noticeably the worst, being strongly skewed towards the blue/aqua end of the spectrum, suggesting that there is too much cyan and not enough yellow.

I've tried running an Auto Color Calibration, however it consistently fails.

Any ideas on what could cause an Auto Color Calibration to fail each time and how to fix that. Or does anyone know a workaround for manually adjusting the color balance? I'm aware of the user feature under the "edit/color" tab which allows the user to adjust the colors via a color wheel. Adjusting green to the yellow end of the wheel actually corrects the problem for copying, however I'd like something more permanent and that would also work for prints.

Thanks for any help!

Drums, developers, txfer belt. Check all these for age and wear.

[mikadonovan]

Re: MPC4500 Color balancing

Ucinn is right. Failed ACC is usually indicative of drums and developer past their usable limits. You need to call your local tech for service as these replacements are a little involved.

[jam-o-matic]

Re: MPC4500 Color balancing

If parts mentioned above are due replace them. I have had good luck, if the density is poor (as often happens in winter) run a forced toner add (SP3-015) and the ACR (auto color reg), if that fails, you need to go into SP's and run the forced line position correction SP2-111, but recall there is a strange order (like C, A, B) to run them in, otherwise it will not pass. Good luck!

[sandmanmac]

Re: MPC4500 Color balancing

I wonder what information we may not be getting here- especially with regard to toner brand. I bet it's either a compatible brand or even an attempt at a refill.
That's where I'm leaning, and in that case, you'll also be looking at a complete set of replacement Development units too.

[Zia Graphy]

Re: MPC4500 Color balancing

Thank you for the replies everyone.

I am using OEM toners, but good thought on that. I am of course using the black drum for all four units. I'll check out the drums and transfer belt to see how far along they are in their life span and let y'all know if that was it.

[verderacer]

Re: MPC4500 Color balancing

Have you checked the music sensors at the transfer belt?

[SargeNZ]

Re: MPC4500 Color balancing

Always pays to bring everything up to PM before troubleshooting copy/print quality. The paper transfer roller gets especially ignored on these machines and can be the cause of issues, particularly if the image looks solid on the transfer belt after a panic-stop.

[Zeldaman]

Re: MPC4500 Color balancing

Hi there!
The thing with the transferroller-assy is a very good idea. When this roller becomes old the ends of the roller look like a heat-roller & you get the craziest copies/prints. Cleaning the ITB-Unit & changing the roller,then colour-reg(techmode) &ACC, system is running in best condition.
Greetings...

[cdog530]

Re: MPC4500 Color balancing

Remember these machines are advertised as copy machines with color capabilities. Its hard to fault these machines if they don't reproduce a certain color the way one person perceives it. That being said...there is a couple things that can improve the image quality without replacing a bunch of parts. Cleaning out each colors drum unit including the charge rollers, cleaning the ID sensors above the ITB belt (toner seems to collect up on the shutter and gets to those sensors). Making sure the laser shields are clean and optics for getting an accurate ACC. Wrap it up with a color registration and ACC. There is a certain point where you can't clean worn out parts but if you go through these steps you can get a drastic improvement of image quality.
-C

[Zia Graphy]

Re: MPC4500 Color balancing

Just wanted to let everyone know that this problem was resolved. It was indeed the drums needing to be replaced, they were getting a bit old. After replacing the drum units I ran an ACC and it completed. Green and red color mixing now looks fine and the customer is happy.

Thanks for the help everyone!