CLC4040 misregistration

[Indigger]

Hi guys. I'm pretty new here, while i'm having a decent experience in industrial digital printing I never had a chance to work with smaller machines... untill a friend of mine asked for a help.

The problem started with misregistration is scan direction ( PG6 lines along feed derection are pure black at front but start to show some misregistration closer to center and at rear we can see 1 mm between color lines. All the lines across sheet are registered well, look pure black).

After reading the manual I came to conclusion that it a "Reproduction ratio" problem which can be corrected only by timing of video feed signal into the lased head as a result automatic test, when the sensor measures chevrons at front and rear.

So I cleaned the pattern reading sensor, checked if the sensor's shutter opens normally (it was opening wide enough for sensor to be fully uncovered) and found that the result was zero...

Afterwars I decided to follow one of advices on this forum and reset the registration values (Function/Laser: LD-ADJ-Y, LD-ADJ-M, LD-ADJ-C. Enable with OK and COPIER > FUNCTION > CLEAR > REG-CLR)It did changed the situation - now the image starts 5 sm after leading edge and the misregistration in sub-scan is about 9 mm. I should've been happy to see that the initial problem has gone - now the PG6 lines alonf the feed direction are evenly misregistered at front and at rear (please see the start of this message) but somehow I dont feel happy at all :-)

I am going to try tomorrow the manual resetting laser cams by rotating them to center position.

Since I have no idea how the system should work I can't predict what result I will have... I'll post it here for sure.

I'm sorry if this post looks too long. If someone wants to to share the knowledge of sacred Canon misteries I would appreciate it.

[MunsterTech]

if you do an autogradation, are all the 4 colours lined up perfectly, if its a registration issue, the 4 colours will be all over the place instead of being perfectly in line at the top of the page...its a very quick test to see if its a registration, could be as simple as ITB slipping.

[Indigger]

if you do an autogradation, are all the 4 colours lined up perfectly, if its a registration issue, the 4 colours will be all over the place instead of being perfectly in line at the top of the page...its a very quick test to see if its a registration, could be as simple as ITB slipping.

Below is autogradation sample if I understand it right. Sheet A4, leading edge is at bottom of image.

IMG_20140926_203217.jpg

And I did not mentioned in initial post that when I stopped printer during auto registration, when machine prints chevrons, and looked at ITB, chevrones were overlapped so the colored lines were criscrossed at the ends.
About ITB slipping - I believe in this case the image should be shrinked in sub-scan direction, right? Here I have perfect geometry and misregistration up to 8 mm between colors and this distanse changes every time when autoregistration is done.

Below is PG6 sample, full size and enlarged. Leagind edge at top of image this time.
IMG_20140926_203238.jpgIMG_20140926_203251.jpg

I'm begging your pardon for the pictures' quality, I was in a hurry and used my phone

[MunsterTech]

as i suggested, when you look at the auto gradation sheet, you can see that the colours are all over the place instead of being inline across the whole page. Seen this problem alot on the 3200s and 4040s, Canon insisted it wouldnt happen on the 4040s but infact it was a common problem, something if i remember that the main controller "remembered" older settings and woldnt adjust the lasers.

several ways around it, go easy options first, take out the ITB assy, remove the belt and scrub and clean the big rubber roller, refit the belt see if that sorts out the issue. Do a P print under copier-function-misc p and P print. Do you have a Feiry RIP on the machine? if after doing the ITB its still an issue, you can clear the DC and MNT-Con (main controller), however if you do that, you will have to turn IMG-CONT onto 3 otherwise it wont recognise the RIP as being installed. With the printed out reports for P print and network report (wont need network report if you have the feiry), re apply all the values under Adjust and any other values from the P print, reboot and you should be ok.

Its not a nice thing to do first time, just take your time, make sure you have all the reports printed. Usually works though. good luck

[Indigger]

Thanks for your advice, MunsterTech, I will try to do this in Monday.
I do have Fiery H1 so I will remember switch IMG-CONT to 3.
What puzzles me is that the misregistration became much worse AFTER I reset registration values (Function/Laser: LD-ADJ-Y, LD-ADJ-M, LD-ADJ-C. Enable with OK and COPIER > FUNCTION > CLEAR > REG-CLR). I understand that starting from scratch should get rid of every problem that is not caused by mechanics but it is so lengthy prosedure so I hoped to do the trick with smaller efforts.

[skynet]

As Indigger has stated clean itb assembly before anything else, also check drum life, overused drums drop toner onto belt assembly.

[Indigger]

I did noticed some toner where it should not be, I can see it even on gradation sample I posted. As far as I understand the only way it can affect registration it is when spilled toner partially covers registration marks on ITB during auto adjustment. When I checked these marks by stopping the printer and observind the ITB I found that lines and chevrons have normal straight edges, background was clear from toner. It is only that the chevrons are overlapped. I just winder if it is the reason for misregistration or a simpthom?

[MunsterTech]

you could always take out the ITB cleaning assy, 1 screw, and see then how the registration is, you will have all the chevrons and maybe a bit of dirt on copies but it will see if the cleaning assy is sticking to the ITB and causing misregistraion...just an idea

[Indigger]

That's what I did to look at these chevrons - took out ITB. I am just trying to figure out where this problem came from.
If I put all the things happened in a list, I see that this big misregistration cannot be caused by mechanical problems like belt slipping, gears worn out or cleaning assembly stuck to belt.
1. I had misregistration in scan direction, on rear side.
2. 1 cleaned and checked ITB and all things around with no luck. Though logic says that this type of misregistration cannot be caused by the belt movement. Belt should give sub-scan problems, isn't it?
3. I reset registration parameters as I wrote earlier and after this I have very bad SUB-scan misregistration along with image displacement in sub-scan. It is obvious that the problem comes from wrong parameters and machine cannot correct itself, probably because the registration paremeters went off too far (chevrons overlapped) and need to be corrected manually.

The problem is I have no idea which parameters to correct so I probably will have to follow you suggection and clear all the settings, DC-con amd MNT-con

[MunsterTech]

here,

read thru this, its for the clc/irc3200 series but same issue on that machine as its brother the 4040, should guide you thru the main controller clear etc