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yellow bands fuji 370


christophe

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I really need some help with my fuji 370, a month ago it started making yellow bands on the prints always in exactly the same place on the photos and parallel to the movement of the photos through the machine. The bands are mostly visible on lighter colours on black or dark parts of a photo there usualy not really visible. Right now with business being as hard as it is theres no way i can afford to get a technician in or replace the lazer.

Everything i could find online said yellow lines parallel to the movement of the photos would be more than likely dirt in the optical path. I had a look inside the lazer and gave it a quick clean but there was no visable dirt anywhere to be seen. In fact if anything that just made the bands a bit worse! Now today for the first time ive started getting random temp errors aswell. Could bad grounding in the machine be causing the bands and the temp errors or what else could it be? If it was bad grounding would the bands be always in exactly the same place or would they be more random? Are the 2 things not connected? I will attach photos of the bands and thank you very much for any help you can give me in advance!

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I had similar trouble on a 390 and found a light leak above the densitometer. you can have problems with light leaks if the shutter between the Dry and wet sections. Also have a visual check of the magazines, sometimes the guides get turned and can leave a little light in. However, if the problem exists for more than one paper size, then I would think more a light leak. In the dry area of your machines, be sure to use black screws as silver ones will reflect light that might not otherwise be a problem.This happened to me once where I had one of the units out and replaced a black screw with a silver one, when the light shutter to the wet section opened, I got a reflection across my print.

When looking for a light leak visualise the paper in the machine as a meter of paper or more goes into the various units and waits. I am presuming the print you are showing us was on 4" or 102mm? if so, the light leak is on the left side as you face the wet section.

Another reply has suggested the laser unit, a way to check this would be to see if the fellow streak is on bordered prints all the way trough the print including the border. I hope that helps.

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Thank you both for your replies, yes the bands appear on all sizes of prints but in a different place on different size prints. I am thinking the lite leak is possible due to the placement of the bands on the prints, but i dont understand how my cleaning of the mirror could of made the bands slightly worse if its a light leak. But i will have a look where the leak could be and clean the mirrors again maybe. Thank you both for your help its very much appreciated.

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Do a bordered print then, you will see if its the laser or a light leak as the laser will only affect the printed area and not the border. I would not mess with the laser too much as they are quite expensive to replace. I still think that you have a light leak and not a laser problem. Check all your panels, that they fit properly, check the doors, that they close properly. As you change paper sizes, there are mechanical changes, so it would be normal enough for your light leak to look different on different paper sizes. Check also on your wet section, that the filter holders are in properly and there is no chemical residue keeping them slightly out of place. Keeping the cover on this area also helps. If I was you, the laser would be the last thing I go after, I would check all the things I gave you first. The light fogging looks to me like artificial light getting in and not any dispersion of light in your laser.

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ok we cleaned the optical path in the lazer again as best as we can, and checked for any light leaks and bad electrical connections, but nothing has helped. If we do a bordered print the border is fine aswell so we dont think its a light leak. The bands only show in light colours never in the black or dark colours in a photo. Somebody suggested to us it must be the scanning mirror because of the fine small bands surrounding the large central band but we really cleaned the scanning mirror well and it didnt help. What else could it be? Thank you again guys for your help. Ive attached another photo i think shows the lines a bit better. Thank you again everybody.

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How do paper feeds look? they follow a different track trough the machine and it would rule out the mag and pre print areas. You have said that you were in the laser, any chance you have replaced a black screw with a silver one in there? The streaks are relatively well defined so, your problem is close to the paper I should think. This may sound strange, but can you try and print with all lights off around the machine? The colouring of the light streaks would suggest florescent lighting? If you print in darkness and still have the streaks after a few metres of paper, then you can most definitely rule out a light leak. Can you tell us if it is constantly there for all prints even if it can not be seen too well on dark prints? Does it happen from both negative and digital printing?

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