Troubleshooting Fuser Jams in the Docutech
By Raymond Cote

Applies to the 5090 family as well

One of the nice things about working for the manufacturer was the ability to order anything you need to repair the copier or printer. And you do not have to pay for it in real dollars.  On many occasions when I was having problems in the fuser area I would order any parts that looked like they were worn or possibly defective in some way.  Usually the shot gun method fixed the problem and I was off to my next call.  I always thought of myself as a good technician and always fixed the problem. When I started my own copier repair business, I figured I had seen everything and repaired it all. The only problem I encountered was carrying about 10,000 extra parts in my van. The gas mileage in my van was poor to begin with but with the added weight of the unnecessary parts that I had in inventory, it made my gas mileage impossible.  After about 6 months on my own, I discovered that I truly didn’t know squat about the Docutech. Now I was able to diagnose the problem down to a specific component. My level of service improved and my (carry it all) inventory diminished considerably.

The most critical aspect of working for yourself is communications with your customers. When they call in for service, telephone diagnostics are essential. We used to call it “call avoidance”, and sometimes it would work and sometimes it didn’t... But the key element here is getting the customer to give you a clear picture of what is happening with his/her copier. Including any and all service codes.  I would start my troubleshooting process before I arrived at the customer’s site. By that time I had several components in my inventory that I suspect might be causing the problem. This was an effective way to minimize down time. The customers were always happy for the quick repair and they were back on line in no time at all. Compared to the manufacturer, the tech would respond to the service call on one day and order the parts he needed and return on another day to install them.  Depending on what district the business was in, it could take several days from the initial call to the actual repair to be completed.  When you are in business for yourself this is an unacceptable practice because the customer will always remark that if they wanted abuse they could have remained with the previous service provider.

I have been asked on numerous occasions for solutions to various field problems and I would like to share a few of them with you today.  One topic that I have been asked about on many occasions is the fuser air knife assembly (PL3-D11).  If you are experiencing numerous paper handling fuser jams, examine the fuser idler gear (part number 7K1700).  If the teeth are feathered and razor sharp, then it’s time to replace the idler gear. Also, I would also examine the fuser drive gear 7K120.

With that replaced, and you continue to get fuser wraps and jams, you will want to examine the fuser compressor air system. Select 25 copies and start print. Open the left (12 inch) access door on the extreme left of the copier and observe the air pressure gage. The Pressure Regulator Assembly (PL3-E5) 53K911 should be adjusted to about 20 to 22 pound for best puffing. If you observe erratic behavior on the pressure gauge, it might be due to a bad solenoid in the system. The usual culprit for erratic (or loss of) air pressure between the compressor and the air knife could be the solenoid (PL3-D11) part number 121K5500.

Actually that little air gauge can tell you a lot about what’s happening inside the copier.  If the air knife solenoid is not opening and closing properly you will see a gradual loss of air pressure until there is a mispuff. Examine the solenoid and see if the hardware is snug and the solenoid is operating properly in diagnostics.

Open the fuser drawer assembly, cheat the fuser interlock switch, open the stripper assembly (PL3-D11) part number 54K1301 and while you are in diagnostics actuate the Air knife manifold solenoid. You should be able to feel the stripper air puffing on your hand. It should be consistent and with equal force when it “puffs” all across the entire fuser puffer air knife manifold assembly.  Examine the holes on the air knife manifold and make sure they are not clogged with toner. If you find any blocked use a standard staple to ream the hole out. The (standard Swingline desk top) staple seems to be about the right diameter to ream the hole out.  Do not use any chemicals to flush the holes as they will probably get clogged up again due to the chemicals.  Next I would check the air knife manifold height (clearance) adjustment in the adjustment section of the service manual (ADJ 10.12).  Loosen the four (4) 7 MM screws on the Air knife Manifold and hand tighten them. Open the Air knife manifold and insert 8 sheets of 14 inch paper (lengthwise) on the fuser heat roller and close the manifold. Gently use pressure to ensure that the manifold is seated on the 8 sheets of paper. Snug up the 7 mm screws with a wrench. Carefully raise the manifold and tighten the 7 MM screws, the adjustment is complete.

The next thing you may want to examine is the prefuser transport assembly (PL3-B13).  The belts should be replaced at about the four (4) million copy count. Use kit number 600K8320 (PL3-C1) if you have reached the threshold count or if any belts are worn or damaged in any way. While the prefuser belts are off, check the air holes on the transport assembly and clean them if necessary. When the holes are blocked they will often reward you with prefuser jams.  As the belts age, they will become elongated and may not drive the paper properly.  Don’t be deceived by good looking belts if you are having prefuser transport jams they could be stretched and not able to drive the paper properly. Actually, in my experience with non-manufacturer belts, the service life is much shorter.  Dollar for dollar the best replacement belts are from the manufacturer.

With all of the above completed and you are still experiencing fuser jams, the metering assembly (PL3-E1) should be examined next.  Before you begin, look at the fuser agent level in the Housing Assembly (48K27280).  Is there fuser agent in the tray?  There is no official depth of fuser agent in the housing but 1/16 inch coverage is sufficient to keep the heat roller coated with fuser agent. Check the fuser agent pump (PL3-E3) 94K2030 in diagnostics to see if it is actually pumping fuser agent into the tray assembly. By the way, what type of fuser agent are we using today? If we are using the fuser agent in the BLUE plastic bottle, then we need to flush it all out and use the real fuser agent in the orange bottle.      

Replace the fuser wick 94E680 and the metering blade 33E1110. Check the Metering roller assembly 22K9162.  Is there more than 6 million copies on the roller?  It’s hard to see with the naked eye, but the metering roller has a texture and after 6 million copies, the surface will start to become smooth and not carry the oil up to the Donor Roller 22K27670. By the way, if the Donor Roll is damaged in any way or if it’s discolored with a contaminant I would go ahead and replace it as well. We all know what happens when we do not get the proper coating of oil on the heat roller. While the metering assembly is out of the machine carefully examine the front cam bracket (PL3-E4) 31K2970 and the rear cam bracket 31K3390. By manually actuating the cam brackets (loading them with pressure using your hands), watch to see if they are even when the cam engages. Usually an uneven coating on the heat roller could be caused by uneven pressure by the cam brackets. The best way to examine the metering assembly is to compare it with one that is in working condition from another copier. Usually when they are side by side you can sometimes spot the problem much quicker.  As a last resort you may want to substitute a metering assembly from another machine just to see if it works better than the one that came out of the machine in the first place.

As a last resort, closely examine the heat roller (PL3-D14) 22K41520. Is it coated with fuser agent? Is the Heat roller damaged in any way? Is it discolored? Is the temperature set correctly to 390 degrees (ADJ-10.4)? Extremely old Heat rollers have been known to cause fuser jams when the coating becomes contaminated.  Does the customer run 3 part, or 4 part pressure sensitive carbonless paler?  The paper will leave contaminants on the heat roller and cause problems as it is being used.  If the Heat roller is old, try a new Heat roller and run diagnostic dc-701, Heat Roller Preparation. Check the fuser roller bearing by using a dry cloth to turn the Fuser roller by hand.  Be extra careful not to touch the heater rod (126E340) because when it’s extremely hot it could shatter and then will have to be replaced. In one rare occasion a heat roller inboard bearing was binding when the machine was on long runs and the temperature went above 390 degrees. In this particular occasion the Fuser Roller Thermostat (PL3-D10) 130P225 was misadjusted so that the copier would not go into an overheat condition.

It’s interesting to note that a few field service techs have reported that the root causes of some fusing problems were the Power Boards.  I have to respectfully disagree. The Power Boards in the circuit are, for the most part, extremely reliable and do not fail as often as we think they do.  If you use circuit power boards in troubleshooting fuser problems make sure you identify what boards were used (where) and what the code was when you replaced them. Before you discard any PWB’s or send them in for refurbishing make sure that you try them on a machine that is working. If the problem returns then it will be safe to assume the PWB is defective.  Sometimes just unplugging P/J connectors on a PWB will fix some oxidation problems on the pins themselves.  

Some Field engineers in Rochester have firm beliefs that if the PWB has an RC network its conceivable the PWB could keep the error message (active) until the RC network is discharged.  I call it “magic”. For the rest of us, unplug the PWB and put it in a nice dark place for a few hours and then try it again.  The capacitors can do some neat magic on the circuit and sometimes can drive you right up the wall.  That’s why it’s always a good idea to use the Po- Po process every once in a while. The Po-Po is defined as Power off – Power on.  And after the copier has gone through initialization and is in a ready state continue to do your troubleshooting.  This is especially true for the Docutech and the 4135 family of system printers.

As the weather gets cooler the copiers and system printers will do some funny things. It’s all due to the change in the ambient temperature and the humidity factor. Call activity will rise when the temperature changes and its not scientific mumbo jumbo. I think the machines actually feel the difference in the temperature and it’s their way of telling the customer that they want to go to Miami Beach for a week.  My wife tells me that my mind works like lightning. One brilliant flash and it is gone.  What do you think?  All kidding aside, I would like to thank everyone that has sent in suggestions and fixes to make this column possible. Your input is greatly appreciated. I can be contacted at VillageCopierNY@AOL.COM.   If you would like to submit a repair to a problem or comment on any issue please feel free to write to me.