Image defect on KM 6501 - OCE-CS665

[Stirton.M]

	Quote:			Originally Posted by resolute
	Thanks for all the suggestions... The defect is on all stocks... more pronounced on heavier stock (ie. 250gsm+). If I print a photograph -- the image defect is somewhat hidden, but if I print a greyscale image or halftone -- it is very very apparent.

Try a mixed halftone, with black and cyan. Pattern 53 and 100-120 halftone on the two colours. I want to know for certain if there is no repeat in the cyan. It seems strange that this only affects black and not the other colours.

Swap the drum drive assemblies between black and cyan.

Also, try a complete belt unit swap.

[Albonline]

this looks like a speed blur to me, which would mean somthing is affecting the speed of the black drum or developer units. saying that the heaver the stock the greater the defect points to paper feed system overload. ie motor drawing too much current or slowing so much that the other motors in the copier cant sync with it.(going beyond pll range)

[Albonline]

hint try running a grid pattern, see if image is distorted.

[Gerry.Fitz]

Hi ya
I have had several versions of this problem ...fist can you check if it is media related ..if it is card it will flick and cause a bounce which will give you the line and it will get worse the thicker the card this m/c will only run paper or you have not set your loop or pre registrations correctly.
Gerry

[TonerMonkey]

This is a jitter problem with heavy stock hitting the bottom of the transfer belt causing the mark - a special rom was brought out for the 6500/5500 which racked the CMY transfer rollers out when doing black thus taking the slack up on the belt and resolving the problem.

Best practice would be to make sure firmware is up to latest level. Otherwise I could find out which firmware sorts this problem, it has been known to happen on heavier stock on black only.