C452 Colour Issues

[Marsh2]

Hey There

I was wondering if any one can help me or has had this problem before. C452 the colour which it produces is always sliding away from an acceptable quality. If the customer preforms a reset and stabilize then it comes right but then it slides again over two days. I have read something one this fault before and saw something about repacing the AIDC sensors which i have done but it is still playing up.

Any help would be appreciates

Cheers Justin

[Stirton.M]

First of all, who ever told you to change the AIDC sensors???? Dunno who or why or where, but that is not good advice.

Image stabilization is a complex process on a colour machine. See the attached file for a detailed explanation as seen in the theory of operation manual.

Since there is no mention in the TSB of this particular machine on your specific problem, I would first concentrate on ensuring the firmware to the machine has been updated to the latest, which happens to be B4, as of June 15. There is special firmware which is newer than that, but not recommended unless you have specific issues that those special firmware's address.

Also, ensure the IDC sensors are clean. These are the sensors that can be found on in the vertical transport area. Remove the belt, the two sensors are found there, under the belt, facing upwards. A protection plate may be covering them, you'll need to gently push that to one side to expose the sensor window, clean with a cotton cloth any dust that may be on the window of the sensor.

You should also be able to set the span range of stabilization period to the shorter interval. Keep in mind that the machine will do a stabilization more often, thus affecting overall productivity on the machine.

[Marsh2]

Thanks for you help but firmware is up to date and the AIDC is the same sensor as IDC just an older version but thanks for your help. So still needing some help here please....!!!!

[RRodgers]

You should also be able to set the span range of stabilization period to the shorter interval. Keep in mind that the machine will do a stabilization more often, thus affecting overall productivity on the machine.

As mentioned above, that will probably be your fix right there.

[BIG PAPA]

Also, what type of environement is this? What type of volume, and what do you mean by color is sliding away from acceptable? For color crucial environments color calibration is recommended daily, if not before every job. yes this would be crazy and no one will do it. Is this the same job? Comparing color from one run to the next? Different jobs? What type of files? Are the users educated in the programs they are using? What is doing the color managment the software or the machine? Some random thoughts and questions.

[Stirton.M]

Thanks for you help but firmware is up to date and the AIDC is the same sensor as IDC just an older version but thanks for your help. So still needing some help here please....!!!!

Yes, I agree that these are relatively the same thing, however the point I was making was that to replace them was bad advice. If you do an image stabilization and it is successful at that point, the sensors are not at fault. If one or the other were failing, you would not attain this and the machine would constantly generate P-Codes related to the problem, along with a likelihood of registration errors. If they are dirty, for example, some toner dust has covered them, even a little dusting, will throw off overall stability and also produce P-codes.

The advice Big Papa gave is also relevant and important. Environmental conditions such as humidity and temperature, barometric pressure can all adversely affect colour stability. It is this reason that I recommend to users who need colour accuracy to be proactive in their daily use, as Big Papa mentioned. Every two days is really not surprising and is likely a lot to do with these factors.

[Marsh2]

Thanks guys

I have read all your remarks and maybe I need to clarify things more. This problem will only resolve with reset and stabilize does this occur on the normal operation of the machine or only the stabilize. Also when I say the colour slides I mean a white object on the page will become pink in colour. The customer under the same environme

[Marsh2]

Thanks guys

I have read all your remarks and maybe I need to clarify things more. This problem will only resolve with reset and stabilize does this occur on the normal operation of the machine or only the stabilize. Also when I say the colour slides I mean a white object on the page will become pink in colour. The customer under the same environment had previously run a c250 with no issues. I will endeavor to shorten the stabilization time to see what happens.

[Stirton.M]

This is quite a bit different.

You are referring to colour registration, which is a whole different can of worms outside of colour stability. Again, the IDC sensors would be a factor, but as I previously mentioned, if you are able to attain correction on demand, then the IDC sensors are OK. There is mention of replacing the IDCs, but the symptom is that the second and consecutive pages in a single job have colour registration variance within a single job.

Colour registration can be a bit more involved, but is correctable with some patience. You are more than likely also getting P-codes associated with this.

Some areas that can produce colour registration issue can be the IU itself, in this case, the magenta IU is drifting. The IU itself may be at fault, or simply is not seated properly. I verify by pulling the IU out a little and firmly reseating it and locking it in place.

There may be a problem with the magenta first transfer roller on the belt itself. We've had some of these with broken holders for the rollers.

Or the transfer belt is worn. Resetting the belt life once will usually be ok, but if reset more than once, wear on the surface will affect colour registration. In some cases, premature wear will also happen, same effect.

There could be a problem with belt cleaning. You can manually set the belt cleaning bias up one point or down one point for the positive and negative bias cleaning respectively, to help in the cleaning process.

There could possibly be a problem with the laser unit, though I have my doubts. Replacing this may resolve the problem, but before you do, perform the following adjustments as described from the service manual attachments.

[Marsh2]

Hi Again


I dont think i am explaining it very well i will attatch some examples of the colour changes. It is not the registration that is out and the IDC's(AIDC's) have been replaced with new ones.
The colour changes enough that a photo of a nice white IMAC for examples comes out pink in colour the reset is preformed and all the colours are fine. This client is just printing standard business type colour stuff and isnt that worried with needing exact colour just not some many big jumps in colour. They do similar prints at different stages and find the colour varies drematically for week to week unless they do this reset all the time. It can change half way through the run. I dont believe these machines are a C6500 but i dont think these variances shouldnt be as often and drematic as they are. They were using a C250 for 4 years with out to many dramas. Is this a problem with the machine or design or colour persific to this model.


Cheers Justin

if you open both pictures and flick between the two prints you will see a vast change in the bird picture and this is a good example i have seen a worse change than that.

[RRodgers]

Mid run changes in color is a problem, color changes from week to week are usually lack of calibration. I looked at what you posted (err glanced) it does seem like Magenta might be a tad heavy in the highlight area's. Have you tried just changing out the IU for Magenta? Course remember... just cuz magenta show's up may NOT be the problem... it might be the only color that is working properly. but... by looking at what you posted it does look like cyan is being reproduced properly. Weird as I didn't see a Yellow gradiant.

[Stirton.M]

Ok, picture is worth a thousand words.

I agree with RRodgers, this looks to be more like an IU related problem. There could be a problem with the IPB as well, it might be worth your time to change out that board if you have one available. Don't order it if you have none available, but if you have a spare machine and can do a temporary swap, that will help eliminate that section and rule out most of the electronics related. Though I highly doubt it, the PRCB may also be at issue.

RRodgers, it irks me that KM did not adopt a similar test page to the Fiery, it would help to know what each component colour was doing outside of the process.

[Imsdal]

I am wondering what did you do to fix the problem Marsh2?