Konica 7165/7155 Developer Dumping Solution

[d7guitar]

The Konica 7165/7155 models are known for developer dumping, grainy copies (using developer to create image) which causes premature fuser roller wear and light or washed out CQ which is worse on 2nd side. Solution:....... (This must be followed exactly as stated otherwise you will not realize a fix). 1 Verify PM, drum and developer counters are correct and reset after replacement (do not extend PM count or this will NOT work). 2. It's best to start with a fresh FULL PM, but if not, check clean and/or replace as neccessary the; charge wire, grid, charge cleaners, toner guide roller, and blade. 3.Check Drum-to-ground resistance. Spin drum in 47 mode 4-1-*-1-start. Measure from drum shaft screw to frame. Should be UNDER 80 ohms. If above, install lamp pressure plate (p/n 55FA53170). Attach to one of the 3 available near-by screws on the front of the drum carriage so that the plate touches and rides along the inner drum bearing race. re-measure. Should be less than 20 ohms now. 4. Make certain that Drum voltage is set correctly (see service manual) 5. Remove developer unit and set on level surface. Remove top cover. Set meter to lowest ohms scale. Hold one lead against set screw for doctor blade. Hold other lead against outer edge of mag roller where you can see the alluminum. Spin roller and read (may need help with this part or use wire leads with clips). Should read LESS than 20 ohms at all times during test. This is the most critical part and the MAIN cause of entire problem. If this is failing, nothing esle told here will work untill this is repaired. Options (a) replace developer bearing, remeasure and if new one is below 20 ohms, you're okay (careful, I have seen many new ones read bad) (b) Add modification to mag roller sleeve. (this is what my service dept. does and EVERY one of our 30 plus machines run clean with excellent CQ). We use p/n 26NA45140 (spring, reg) and connect both ends to the bias pin that protrudes from the back side of of the Dev unit (this is where it gets it's bias connection from the main body) and stretch it over the mag roller shaft giving the mag roller %100 continuity. This completly eliminates the mag roller bearing for bias transfer. NOTES; slightly stretch the spring before attaching. This will lessen the "lathe" effect on the mag roller. AND use an oil on the shaft (synthetic works great here) where the spring will be touching to eliminate any squeeks or squeels. Re-install and Run all drum peculiarity adjustment by the book. These procedures were created by our KMBS DSM and my team. We have %100 success with this procedure. There can be many variations to your solution, but remember all of the steps are critical to correcting this problem. Skip steps and you wont see improvement, guaranteed. No bias to mag roller = overtoning, misting, dumping, gritty copies and poor CQ. If anyone would like the procedure sheet, please request it at randolphj@martingroup.com. Happy fixing.

[mitchl]

Oh my the first machine I tried this on was like the poster child for this procedure. Toner every where, No bias what so ever, put the spring on the thing and its got bias out the ying now, time for a full PM and to follow ALL of the instructions to the letter!! Thank you John!

[mitchl]

Welll this is the fix all end all for these pigs........Hmmm maybe there not pigs after all. I followed the instructions to a T and just got through running over 10k copies of an original that is about 70% fill and you can still eat out of the inside of this former toner spewing monster.......................... John Randolf thank you!

[mrwho]

Thanks for your detailed description. I think I might've solved a customer's problem with it - still in testing, though.

It's hard for us to get an hold on this spring - 26NA45140. Did the Konica-Minolta merger give this part a new part number?

If not, does anyone know of a good substitute?

Cheers!

[SAR]

That spring is the registration roller wrap spring for the front and rear ends of the rollers on the old 7020 series copiers.
We just steal them off of old 7020 series machines in our warehouse, but if you have to order it new try 26NA45141.
This is the same spring on the newer version machines (7222,7235).

[Albonline]

we do a simaler procedure except insted of spring and plates we use conductive grease in the drum and developer bearings. also check h cut or doctor blade distance
(5sheets 20lb bond work pretty good as shim/guage)
developer mag angle also plays into the spew factor. there is a bulletin about mag angle setting.






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[mitchl]

PSSSST..... If your talking about the spring from the Mag roller to the bias pin any old spring will work just stretch it out so it doesn't create to much pressure on the shafts so it doesn't cut into it..... I've used a paper clip in the springs place before as a temp.