B&W 250 350 ATDC Sensor Gain ? c2557

**Hansoon** · 10-01-2009

Can solve the problem or just extend the life of it ?

No long term experience yet but we expect it to be a greatly extended life. According to KonicaMinolta the Image unit for the BH200, 250, 350 should last around 400K. I wouldn't be surprised if we can double that, provided that the Mag Roller end-seals are being replaced on time as well when damaged.

All Image Units of the same the design such as the Di-250, 350 / Di-200, 251, 351 / Di-2510, 3010, 3510 and especially the Bizhub's 200, 250, 350 are suffering from drum damage caused by premature MagRoller Rear-Collar wear. You'll find sometimes collars with significant reduced outer diameter and enlarged hole at the same time. This allows the drum to come too near to the mag roller at the same time ripping the seals causing even more havoc. The modified collar with integrated ball bearing prevents this. This is no new technique, machines designed with less "Cost Cutting" in mind use this construction since decades successfully.

Hans

**DadO** · 10-02-2009

I changed 4 drums till i didnt realize that. I cant get more than 150K form DV.
I had teory that corona is tearing drum, more specific would be that a small plate where the paper lays down just before charge roll is touching the drum, causing tear.
I actualy modified the corona. I took that small black pad's that rise the level of corona from the used one and place it on the new so that plate is puled away from the drum. now i will leave same corona but new dv and drum and will check from improvements.

**Hansoon** · 10-02-2009

Measure the diameter of the rear mag roller collar, it should be 18.65mm for an unused one. We found many under 18.50mm which is, together with the weared out hole of the collar, reducing the space between drum and mag roller. This allows the drum to push against the mag roller endseal which in turn than is forced on the mag roller itself. This will finally tear the seal and damage the drum surface even more.

The worn collars can be easily recognized without taking them out, look for the difference between the front and rear collars, compare how differently they wiggle on the shaft. Its always the rear one which has much more play, likely because there's obviously a momentum coming from the drive gears making more strain on the rear collar causing additional wear.

Hans

**mjunkaged** · 10-03-2009

I'm factory trained, there's a fuse that blows when you install a new I/U in the machine. It's in the connector assembly underneath. You can order a PROPER rebuild kit for the I/U with developer(starter), hit rollers, drum, blade, fuse for about $90 u.s.

HOWEVER: I don't believe you should even bother with all this if you want reliability and no hassles like the ones you're having!
Run the I/U 100% past life??? Sure, if no one cares about print quality or fuser life!! NOT a cheap or easy fuser to reman., I might add.

A new I/U can be obtained for 50 dollars more OEM and will almost NEVER fail!

Unless of course you have some god-awful aftermarket toner loaded in the hopper that will immediately feed into it.

Can you tell I'm getting a bit tired of spending time on my knees, driving through gridlock and getting stink-eye from customers because of aftermarket supplies???

**Hansoon** · 10-03-2009

This doesn't apply to the Bizhub IU's anymore. They have no fuse and the Image Unit has to be obtained in two parts, the developing unit part + the drum unit part.

There's no part# number for the whole complete Bizhub unit anymore as with the Di-Series. As an Indy I'm grateful for that cause too many customers where getting their selves new units from Internet sellers. Now we rebuild the BH's but unfortunately, probably because of the different toner, the collars in these units are getting worn even faster then before with the Di-Series.

Hans

**minimerlin** · 10-03-2009

You also need to watch out for the transfer roller end spacer horns, they can wear very quickly and the roller bushes damage the drum in the same way!