C6500 Color problems - how to tell if color reg unit is problem?

[dagoof]

I've had a color issue with a c6500 for quite a while now - it's calibrated using an ES-1000 but the colors are too dark, generally only get close by running the driver at 85%, but even then mid blues can be navy, oranges slipping closer to red and too much warmth in the greys - all in all, too much magenta I think.

It's running older f/w, but reluctant to update in case it causes other issues. A previous post had suggested that replacing the whole color reg unit might solve it but I'm wondering if there's a way to diagnose if this is the problem or not?

[methogod]

Re: C6500 Color problems - how to tell if color reg unit is problem?

I would update firmware at least till 60...

FW fixing alot of calibration issues.

how old is developer and drums?

when your running until failure, like we do we find sometimes developer will just give up. may be time to change it out.

Before replacing color registration board, which is not cheap, I would pull it out and clean it well. Its only one connector in the back - hard to get to, but it can get dirty. Also would verifiy shutters are opening and closing properly, check in I/O mode.

If you want to get the older color reg. unit cheap there is one on Ebay right now.

its a little older, but good for testing, i would try to get it for under $75 bucks.

[Mick01]

Re: C6500 Color problems - how to tell if color reg unit is problem?

I would perform the following in this order:
Remove and thoroughly clean the Colour Registration ass'ly
Printer Gamma Sensor Adjustment for the screen that is being used (on good quality bond paper like mondi 100)
Printer Gamma Offsett Adjustment for the screen being used (on good quality paper like mondi 100). Ensure that the this is correctly adjusted.
Run Auto Gamma adjustment.
Calibrate the RIP (ensure you are calibrating to the correct screen, stock you are using i.e coated/uncoated). After scanning the page check the Actual vs target curves to see if you are acheiving (or close to) the targets for each colour.
hope this helps.

[JustManuals]

Re: C6500 Color problems - how to tell if color reg unit is problem?

I would call a qualified tech in as it's clear you are not among them.

[Mick01]

Re: C6500 Color problems - how to tell if color reg unit is problem?

Thats a bit Harsh!

[methogod]

Re: C6500 Color problems - how to tell if color reg unit is problem?

its the first thing i have ever seen posted except for trying to sell manuals.


(but the reg unit is fragile and you can make it worse, if you don't know how to pull it out).

[Mick01]

Re: C6500 Color problems - how to tell if color reg unit is problem?

I agree the unit is fragile and easily damaged.

[Chameleon]

Re: C6500 Color problems - how to tell if color reg unit is problem?

Here is how I diagnose all the C6500's I work on.

Print test page 51 for all 4 colors. If I'm on a C500 I use test page 1 with a gradation setting of 90 for all colors.

Page 51 should start with white and gradually go to solid color. If there is any light or dark streaks consistent in all 4 colors it is in your transfer unit, or possibly fuser. If there are light or dark streaks in a single color, swap charge units or drums to further isolate. I usually move the worst drum or charge to yellow since yellow hides most defects.

The halftone test patterns (1, 51) are the easiest way to diagnose color issues with any color machine. If the test page 1 is solid color (255) it will hide most defects, so use test page 1 set around 70-90. The lighter the halftone is the more prominent the defect will become. The only time I run test page 1 at 255 is with all 4 set to 255. This should look brownish black. Then I run a test page 1 with all 4 colors set to 90. If the 4 colors are not even density this will show which color needs adjusted. If one color is darker or lighter I run the "auto gamma adjustment". Then make more test pages. Charge units causing light/dark streaks are very common with the C6500. As long as 0 is white, 255 is solid for each color, and the halftone looks smooth that is the best the copier can do.

If the colors are still off even though the test pages look good, then it needs adjusted through the program or print driver. Depending on the program you can dial in colors or change the RGB->CMYK conversion. I've had the best luck with turning on "vivid colors" setting in the driver.

[methogod]

Re: C6500 Color problems - how to tell if color reg unit is problem?

other way to further isolate is to mix colors...


yellow and cyan @ 70% each - should be a solid green
cyan and magenta @ 70% each - should be a solid purple
yellow and magenta @ 70% each should be a solid orange

any of the CYMK colors show through you have some issues in a single color.



If your not trained on a C6500 or have alot of practical experience the machine can be a bitch.

[dagoof]

Re: C6500 Color problems - how to tell if color reg unit is problem?

its the first thing i have ever seen posted except for trying to sell manuals.

I think it's the first post he's ever bothered to read without posting a stock reply peddling manuals

True, I'm not a tech (unfortunately I can't change my profile description, happy for mods to do that) but, as I'm ineligible for contract, I'm forced to learn, and mostly get by thanks to helpful board members which I really appreciate. I just want to be as knowledgeable as I can be.

So, thanks for all the helpful replies. I've cleaned the reg assy before (have plenty of experience there from the c500 and have taken care not to damage) but that didn't help. The drums/coronas are all new, but the dev is nearing the end, so I'll replace that soon. Thanks for all the suggestions, plenty of info there to help diagnose.

[JustManuals]

Re: C6500 Color problems - how to tell if color reg unit is problem?

its the first thing i have ever seen posted except for trying to sell manuals.


(but the reg unit is fragile and you can make it worse, if you don't know how to pull it out).

It's obvious that you don't spend much time here, besides giving away FREE manuals to the people who help out here on a regular basis, if someone asks nicely, I take the time to look up and error code and post it.

[methogod]

Re: C6500 Color problems - how to tell if color reg unit is problem?

No judgement. You need to make a living.

[JustManuals]

Re: C6500 Color problems - how to tell if color reg unit is problem?

No judgement. You need to make a living.

Yes, thank you and this is how I make my living. I chalk my time spent here as 'marketing'

[dagoof]

Re: C6500 Color problems - how to tell if color reg unit is problem?

And what exactly has taking pot-shots at me got to do with your marketing? How does that help you earn a living


I've spent plenty of time on here but seldom post as I'm not in a position to advise. I too am trying to earn a living by learning to use my machine to it's best use and, thanks to some helpful people, I can mostly do that. I'm not really interested in this keyboard warrior stuff either, just want to learn. It's a public forum, so I don't really know why you've got a problem with this...

[Itsthepaper]

Re: C6500 Color problems - how to tell if color reg unit is problem?

Remember when you take out the color registration unit, don't just wipe the sensors. Take them off the unit and pry of the clear plastic cover and clean them off good. They load up with toner behind those clear plastic covers and would mess you up.