Konica c308 photo shows printing issue

**Scarekrow** · 06-09-2023

Hello,

So the machine is printing light at one side as shown, changed K drum b4 I realized it also did the same on colour, then changed transfer belt.

Sstill the same, thinking forward from the process the 2nd transfer roller all seemed ok but then if problem was that it would show good on the belt, so would I be right into thinking , it has to be the laser unit?

**JasonSBE** · 06-09-2023

The print head is a possibility. What firmware version are you using, or have you flashed it? I've seen some weird image issues come up that were fixed with firmware on the 8 series.

**femaster** · 06-09-2023

It does resemble a laser issue. If you haven't already, try stopping the machine in the middle of the job and see if the image on the drum surface looks the same.

**4Toon** · 06-09-2023

Defiantly the laser head clean all the mirrors in the laser unit. The main reason for that issue will be your rotating polygon mirror There will be dust or dirt on it. Clean and be carful not to scratch

**Toxic** · 06-09-2023

I have seen and done a lot of dirty poligon motor mirror on 4 and 8 series but never seen pattern like this.
Dirty poligon motor mirror ussualy have effect on top of the paper about few cm to do down and it have gradual change in density.
On this photo there is exact transition and too big area but you can try to clean laser anyway.

**Scarekrow** · 06-09-2023

Originally Posted by femaster

It does resemble a laser issue. If you haven't already, try stopping the machine in the middle of the job and see if the image on the drum surface looks the same.

That would suggest the fault happens between the drum and the transfer belt, as both col and b/w drums did the same and I changed the belt, can I not say the fault is already on both drums and the only thing before that is the LSU?

**Scarekrow** · 06-09-2023

Originally Posted by Toxic

I have seen and done a lot of dirty poligon motor mirror on 4 and 8 series but never seen pattern like this.
Dirty poligon motor mirror ussualy have effect on top of the paper about few cm to do down and it have gradual change in density.
On this photo there is exact transition and too big area but you can try to clean laser anyway.

I will go back on Monday with a spare LUS and do some more checks, the machine is only 18 months old and not in a dusty office so I would be supprised, especially since they are sealed units.

**4Toon** · 06-09-2023

Originally Posted by Scarekrow

I will go back on Monday with a spare LUS and do some more checks, the machine is only 18 months old and not in a dusty office so I would be supprised, especially since they are sealed units.

Probably not a dirty Laser unit but wondering if its still not a laser issue in general. That is where i would start if you have a used one bring one with you when you go there.

**femaster** · 06-10-2023

Originally Posted by Scarekrow

That would suggest the fault happens between the drum and the transfer belt, as both col and b/w drums did the same and I changed the belt, can I not say the fault is already on both drums and the only thing before that is the LSU?

I was just wondering if the pattern was showing up on the drums as well. My thought was that if the drum pattern looked the same, that it would point even more to an issue with the laser. We have replaced a number of laser units on these 36ppm and under color 8-series for weird defects that cause issues similar to what you are seeing. We've had a defective laser unit create distorted images to the entire page on all colors, all the way to at least one case where it only affected 1 color. The issues seem random, but end up being resolved with laser unit replacement.

**Scarekrow** · 06-12-2023

Originally Posted by femaster

I was just wondering if the pattern was showing up on the drums as well. My thought was that if the drum pattern looked the same, that it would point even more to an issue with the laser. We have replaced a number of laser units on these 36ppm and under color 8-series for weird defects that cause issues similar to what you are seeing. We've had a defective laser unit create distorted images to the entire page on all colors, all the way to at least one case where it only affected 1 color. The issues seem random, but end up being resolved with laser unit replacement.

Thanks, I will do another check today before I feel the need to swap the LSU, I will check the image on the drum if I can catch it in time,