Hi Guys,
I just wanted to pass along a problem I ran into that I have never seen before.
I was getting calls for fuser jams that never occured when I was there. This went on for a couple of months.
The jams were random. Could be before the exit sensor, after the exit sensor, in the inverter, etc.
I did all of the usual things and replaced the sensor. the Heat Roll was worn so I replaced that along with the bushings and bearings.
The Press Roll looked good and the bearings did also. Since I was in there I replaced the Press Roll bearings.
After a few days, there is the call again. DOH!
Except that this time when I showed up the problem finally showed itself when the jam occurred mid-fuser.
I rotated the green knob and the paper would not rotate out although it rotated normally.
Ah Hah I thought. It is the pressure springs. Opened up the fuser again but no, the pressure springs were normal and adjusted exactly as I would have expected.
Anyway, long story short, I found out that the problem was the Pressure Roll itself.
You know how the Press Roll is covered with a thin layer of a foam rubber kind of material which is covered with a plastic coating that actually makes contact with the paper?
Well, as I was inspecting it I noticed that it didn't feel quite right. It seemed kinda' thin, papery, and whimpy. No compression ridges, just weak.
And in that was the problem.
You know how you have the fuser nip between the UFR and the LFR created by the pressure springs.
Well as it turns out, there is a second nip that is created by the resiliency of the foam rubber substrate and the UFR.
When it became weak, it no longer applied the pressure it needed to and as the paper would pass through the fuser, the lack of pressure caused the paper to slip/stall and then you lost your timing window and Jam.
Now I have seen pressure rolls fail and eat themselves before but this roll appeared absolutely normal.
When I changed the Press bearings, I never felt it. I just replaced the bearings.
I have been doing this since 86' and have never seen this type of failure.
So there is my story.
Here's hoping that it helps.
Doug
I just wanted to pass along a problem I ran into that I have never seen before.
I was getting calls for fuser jams that never occured when I was there. This went on for a couple of months.
The jams were random. Could be before the exit sensor, after the exit sensor, in the inverter, etc.
I did all of the usual things and replaced the sensor. the Heat Roll was worn so I replaced that along with the bushings and bearings.
The Press Roll looked good and the bearings did also. Since I was in there I replaced the Press Roll bearings.
After a few days, there is the call again. DOH!
Except that this time when I showed up the problem finally showed itself when the jam occurred mid-fuser.
I rotated the green knob and the paper would not rotate out although it rotated normally.
Ah Hah I thought. It is the pressure springs. Opened up the fuser again but no, the pressure springs were normal and adjusted exactly as I would have expected.
Anyway, long story short, I found out that the problem was the Pressure Roll itself.
You know how the Press Roll is covered with a thin layer of a foam rubber kind of material which is covered with a plastic coating that actually makes contact with the paper?
Well, as I was inspecting it I noticed that it didn't feel quite right. It seemed kinda' thin, papery, and whimpy. No compression ridges, just weak.
And in that was the problem.
You know how you have the fuser nip between the UFR and the LFR created by the pressure springs.
Well as it turns out, there is a second nip that is created by the resiliency of the foam rubber substrate and the UFR.
When it became weak, it no longer applied the pressure it needed to and as the paper would pass through the fuser, the lack of pressure caused the paper to slip/stall and then you lost your timing window and Jam.
Now I have seen pressure rolls fail and eat themselves before but this roll appeared absolutely normal.
When I changed the Press bearings, I never felt it. I just replaced the bearings.
I have been doing this since 86' and have never seen this type of failure.
So there is my story.
Here's hoping that it helps.
Doug
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