Weird Image Problem C452

**docfeeder** · 01-23-2018

Hi All

We have a KM C452 which produces gridlines through the prints. A bit of background - it's had new image units where over life, new black developer and drum check for life, but when looking closely the pattern goes through each colour. Transfer belt and fuser have been exchanged also.

The print head unit has been removed, cover taken off and all mirrors/lenses thoroughly cleaned. On replacement full stabilisation and gradation carried out.

We are a bit stumped on this one, so I've attached an image directly off the transfer belt and wondered if anyone has experienced this problem and can help!

Regards

Kev

**allan** · 01-23-2018

Its pitch lines. Its caused by vibration on the drive, it could be anywhere even the waste box....

Or some thing else...

**SAR** · 01-24-2018

We did have those exact same lines on one of those models and it ended up being a bad print head/ laser unit. Have you run the halftone patterns on all of the colors to see if it shows up there?
It's been a while, but I think ours was the black print head.

**docfeeder** · 01-24-2018

Originally Posted by SAR

We did have those exact same lines on one of those models and it ended up being a bad print head/ laser unit. Have you run the halftone patterns on all of the colors to see if it shows up there?
It's been a while, but I think ours was the black print head.

The lines are through all colours, it just doesn't show up so well in the photo. Can you remember what you changed to get rid of it? KM support said change the laser P/H pwb, but no guarantees.

I thought the Print Head was one assembly and not separate units? I'll also look for vibration in the drive as Allan suggested.

Kev

**SAR** · 01-26-2018

It was definitely the print head that fixed it for us. It is just one print head for that model. Sorry, some of the older models had separate units for each color.