Bh1050P image problem

[blago_vd]

Hello everybody,
I have a problem with Bh1050 (7000000 copies). As you can see the attachment on test print 9 , 255 density on the rear side of the image there is a strange pattern with low toner density.
I made maintenance of the fusing unit and 750000 copies maintenance. The drum is about 350000 copies.
Any ideas?
Thank you in advance.

[Stirton.M]

Fuser lower roller...is the sponge damaged? If you print the test pattern with larger paper, 12x18 on 3 sheets, what does it look like? Is there a noticeable pattern? If so, what is its interval distance? Compare that to the surface area distance of your fuser.

Another area I would look at is perhaps there is a problem with the developer unit. With it out of the machine, try turning it with a drill at low speed and observe the brush on the back side to see if that is at fault.

[blago_vd]

It was lack of toner in the developing unit. I made some adjustments with DIP Switches and for now its fine. I will check the quality after 30000 copies to be sure everything is OK.

[Stirton.M]

Wow...so that is what low toner looks like on these machines. On the smaller colour boxes, I usually see the colour start to streak in the feed direction, usually on that end of the page. Surprising that the machine did not halt because of low toner. Might be worth while to look at the hopper sensor unit.