Konica C253 (Olivetti MF250) Dropping Black Developer - See sample attached

[pajeroid]

Have a C253 in the field with the sample problem (attached). Anyone have any experience of this? It doesn't seem like the PRCB problem as this is only on the first page... This gets worse on about the 3rd page.

[suso73os]

How many copies does it have?, I think is an image unit problem, there is a collar in the magnetic roller and may be wasted.

[bsm2]

Bad IU unit

[pajeroid]

Sorry, it has had a new black IU & transfer belt.

[Stirton.M]

Looks like developer dumping, which could be poor bias contacts, failing hv....does the print feel gritty? Is there any developer beneath the unit inside the machine?

Check to ensure the erase lamp is clean, along with the laser window...not likely those are the cause, but I've been surprised before.

[pajeroid]

Hi, yeah the prints feel gritty so definatley developer.... I will try the HV Board & Cleaning this afternoon and report back =)

[rprem]

change this iu to another machine and see the problem comes in that machine also so the iu unit may be defective

[minimerlin]

Have a C253 in the field with the sample problem (attached). Anyone have any experience of this? It doesn't seem like the PRCB problem as this is only on the first page... This gets worse on about the 3rd page.

Did you ever crack this problem? I have the same on a C253...but only when running paper settings that are Thick!! ie Thick1 shows slight problem and as the paper setting gets thicker so does the amount of dump..see my post of C253 K iu problem. I was at the customer today and found that on plain paper all is well!! Weird!

[pajeroid]

From memory I believe we had a faulty batch of black imaging units. The faulty IU's had a skewed drum blade and when corrected; solved the issue. We have had only one since so the problem is still around it seems. If you need precise instruction I will speak to the engineer who solved this issue and get him to write up some instructions. =)

[minimerlin]

I would welcome that information , still wierd that the problem I have only shows when thick media used tho.

[pajeroid]

Solution to incorrect developer doctor blade position

I have had a chance to speak to the engineer this afternoon and we put together these instructions for you... Hope this is the issue you are experiencing!

[minimerlin]

Many thanks for the detail, I will try that on one of the image units that gave the fault and let you know the result.

[fishleg]

mmm how are you reseating that doctor blade even ? Probably just me...

Think I tried that trick once and it was hell I could never get it right. A gradation out of the machine was all over the place.

[pajeroid]

Literally just push it towards the drum with your finger.... just make sure not to touch either the doctor blade or drum with your finger as you will damage the surfaces. Also remeber the drum surface is light sensitive, try to do the work in a dark area - certainly nowhere near direct sunlight.

Once you have adjusted the position, spin the developer using the drive at the rear of the unit and you will see if the developer is evenly distributed.

[minimerlin]

Went back today and did the blade tweek ...seems to work!! Ran 400 prints single sided and duplex on a variety of thick stock all came out ok! No sign of any build up on the IU top at all. Lets hope that this remains as a fix!
Thanks for the info.