DC242 - solid colors great - blue fades not so good

[steveclv]

I have a DC242 with 0.5m copies. Running solids creates great looking images but if I do photographic images where for example there is a light blue sky that fades to the horizon, the color has many tiny horizontal lines. Dark blue skies are affected less but pale blue is the worst.

Is this just a feature of the machine or is there a fault? Is there something that I can do to help with the problem?

Thanks

Steve

[steveclv]

Re: DC242 - solid colors great - blue fades not so good

Update...

I have just done some more tests and it now seems to be more visible on the left hand side of an A4 SEF sheet - i.e the part that comes out last of all - the stripes go up and down the paper in landscape - I'll upload a picture in a sec..

[steveclv]

Re: DC242 - solid colors great - blue fades not so good

Here is the photo - the scanning process makes it look worse that it really is but you get the idea.

Thanks

Steve

PS I ran a color graduation alignment and the sample sheet seems to print OK although the squares are too small to really judgestripes.jpg

[Exok]

Re: DC242 - solid colors great - blue fades not so good

If you get light areas going from lead edge to trail edge, its most often due to developer , developer housing or dirty laser unit window. Sometimes you get a clump build up in the developer housing that gets stuck on the metering blade. This reduces the amount of developer that sticks to the magnetic roller. This will be visible as you manually turn the mag roller by hand. You can sometimes get away with sliding something in like a sheet of paper folded a few times to knock the clump free. It may return in a new location. This often gives you thin void / light bands. You may need to replace the developer and developer housing. Thicker void / light bands are more often due to the laser glass having a build up of toner dust on it. The best way to test is by running solid color test pattern at a reduced fill percentage (50%).

If you get light areas going in the other direction, front to back of the machine, I've seen this caused by a drum being left out exposed to light. Light shock will cause light CQ in areas exposed to light. It shows up as bands due to the frame and parts of the drum unit that block light so those areas are not exposed to light. Swapping drums with another color should result in the bands switching to that other color. If you ever need to remove drums for a period of time or just have the drum drawer pulled out for a time, always cover the drums to protect them from light shock.

[steveclv]

Re: DC242 - solid colors great - blue fades not so good

Thanks, I'll try a toner test pattern first and then maybe try swapping drums

Thanks!

[Exok]

Re: DC242 - solid colors great - blue fades not so good

If the drum swap does not change your symptoms with front to back light bands in 1 color, I would next take a look inside the transfer belt assembly. Each of the colors has a bias roller (1st bias rollers attract toner to the belt, 2nd bias roller pulls all toner from belt on to the paper). You may have a worn 1st bias roller for cyan or some part of the 1st bias roller mechanics is worn / broken.

[steveclv]

Re: DC242 - solid colors great - blue fades not so good

Thanks

After some testing I found that if I changed the color profile to SWOP instead of ISO it gave me a great image with no banding - so it looks like a software issue rather than hardware thank goodness.

Thanks for the info, it's useful stuff to know.