The interesting part of this is that it only jams when there is 350 pages or less in tray #3. I found this out on the 4rth visit after running 500 consecutive duplex copies without a jam. The paper is left just into the bite of the feed and separation rollers.
I suspected that the lift plate was not lifting levelly, levelful, levelness ... (is there an actual word there somewhere?), and was partially correct. I removed the front tray cover and lift motor, and rotated the lift gears manually to observe the lift plate in action. With 400 sheets of more the tray stays level to the top. With 350 or less, when the top of the paper stack reaches the top of tray, the lift plate tips to the right. My theory is that the left side of the top of the stack is hitting the top of the paper feed unit, putting extra drag on the paper.
So why is the lift plate tipping? Without the paper it doesn't tip. Then I thought that maybe my paper had been cut slightly larger than the standard 216mm x 279mm. Nope, exactly 216 x 279, but the tray was 278mm. There wasn't any clearance at the right side of the tray. And the combination of reduced paper weight in the stack, and friction on the right side of the tray was causing it to tip.
OK, so what to do about it? There isn't any intentional adjustment built into the front and rear tray guides, but there is enough clearance in the screw holes to open it up to 279.25mm. I would have preferred to get another 0.25mm clearance, but it is enough to free up the lift.
Problem solved. This one was bugging me. =^..^=
I suspected that the lift plate was not lifting levelly, levelful, levelness ... (is there an actual word there somewhere?), and was partially correct. I removed the front tray cover and lift motor, and rotated the lift gears manually to observe the lift plate in action. With 400 sheets of more the tray stays level to the top. With 350 or less, when the top of the paper stack reaches the top of tray, the lift plate tips to the right. My theory is that the left side of the top of the stack is hitting the top of the paper feed unit, putting extra drag on the paper.
So why is the lift plate tipping? Without the paper it doesn't tip. Then I thought that maybe my paper had been cut slightly larger than the standard 216mm x 279mm. Nope, exactly 216 x 279, but the tray was 278mm. There wasn't any clearance at the right side of the tray. And the combination of reduced paper weight in the stack, and friction on the right side of the tray was causing it to tip.
OK, so what to do about it? There isn't any intentional adjustment built into the front and rear tray guides, but there is enough clearance in the screw holes to open it up to 279.25mm. I would have preferred to get another 0.25mm clearance, but it is enough to free up the lift.
Problem solved. This one was bugging me. =^..^=
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