HP Color LaserJet 3600 paper tray length guide stuck?

Question

I have acquired an old HP Color LaserJet 3600dn printer. Its lower (main) paper tray has adjustable width and length guides -- but I am completely failing to get the length guide (at the rear of the tray) to adjust. More precisely, I can reduce the length but not increase it.

I suspect I'm just failing to do some obvious thing; but perhaps the hardware is broken.

The tray looks like this:

and the rear guide is the bit you can see at the right-hand side. It looks (in real life as well as in the picture) as if the blue bit is meant to move so as to disengage something and allow the tray to be resized -- but it doesn't. (It looks, more precisely, as if you should "pinch" it so that the blue lever-looking thing moves outward. If I do this, it flexes (reluctantly) rather than pivoting anywhere, and even exerting enough force to bring it into contact with the grey plastic housing behind it doesn't enable anything to move.

From the way the guide behaves when I try to move it, it seems like there's a single location where it's refusing to move, at or near the back and roughly along the "rack" running front-to-back that you can't really see in the photo. This seems consistent with the idea that the blue plastic thing is meant to move somehow and disengage something that's obstructing movement.

If I push the guide inward, so as to shorten the paper length, it moves (though it takes a bit of force and makes a fairly loud "ratcheting" sound; I suspect that for shortening as well as lengthening you're supposed to disengage something that I'm failing to disengage). Unfortunately, the currently-set paper length is shorter than my paper :-).

Do I have a broken paper tray or a broken brain? If the former, is it fixable and if so how? If the latter, what is it that I'm failing to notice?

Answer 1

... Ha. As is always the way, I (actually, my wife) found the answer immediately after posting this.

If I push really quite hard on the lowest part of that blue thing I can get at, it does -- with much reluctance -- pivot in much the way it seemed like it ought to, and then the paper guide will move.

(Why the lowest bit? Because the upper bit is thinner and flexes when pushed on, whereas the lower bit is stiffer.)

There's no way it can be intended to be as stiff and sticky as it is, so I'm pretty sure something is broken or worn. But if mine is broken or worn in this fashion, someone else's may be too, so I'll leave this here rather than deleting the question in the hope that it helps some other poor soul with a misbehaving paper tray :-).