fn21 last page of stack not stapled

[Snoman]

I have an fn21 attached to a mx904 when stapling it will miss the last page of the stack or maybe barely catch it if tow sheets are stapled only the first sheet is set correctly the second will be missed. A set of threesheets wil have the same problem unless you hace multiple sets. Then the first set last page will be missed but the others will be stapled correctly because the buff unit will stack them prior to delivery the stapler. Any help will be appreciated Thanks in advance

[SwisSeV]

You might have an issue with the front and rear alignment assembly.

Sharp made a stopper sheet you can stick to them Part #0CW4F507240 for better alignment when stapling.

Refer to MFP-TB-1141 for instructions on how this is done.

[blackcat4866]

A very reliable source forwarded to me the following experiences with that finisher:

Have had this on FN22 (same finisher, just saddle stitch version).
See attached photos.
On my particular machine, I noticed that during stapled sets, some sheets were exiting the finisher much faster than normal, and subsequently ejecting too far out of the compiler before stapling.
I run a load test on the exit roller clutch and found the rollers were able to be stalled very easily with little load on them.
I removed the clutch, and while it looked great from the outside, the inside plates were very rusted & obviously slipping.
A polish & clean of the plates resulted in a perfect functioning stapler.
I ordered a new clutch as a precaution, but after a week delay I was advised that the stapler worked fine all week. I replaced the clutch anyway as a precaution but probably didn't need to. The rusty plates inside the clutch were definitely causing the problem of sheets missing in a stapled set.

FN21 FN22 PARTS GUIDE SECTION 20, item 100. Paper feed dispose assembly.
Directly behind upper inside cover.

Also make sure FN21 firmware is at least version 1.18.01.00

IMG_20160121_085925.jpg

Take this advice seriously. This guy knows his stuff. =^..^=

[sumosoneagle]

A very reliable source forwarded to me the following experiences with that finisher:

Have had this on FN22 (same finisher, just saddle stitch version).
See attached photos.
On my particular machine, I noticed that during stapled sets, some sheets were exiting the finisher much faster than normal, and subsequently ejecting too far out of the compiler before stapling.
I run a load test on the exit roller clutch and found the rollers were able to be stalled very easily with little load on them.
I removed the clutch, and while it looked great from the outside, the inside plates were very rusted & obviously slipping.
A polish & clean of the plates resulted in a perfect functioning stapler.
I ordered a new clutch as a precaution, but after a week delay I was advised that the stapler worked fine all week. I replaced the clutch anyway as a precaution but probably didn't need to. The rusty plates inside the clutch were definitely causing the problem of sheets missing in a stapled set.

FN21 FN22 PARTS GUIDE SECTION 20, item 100. Paper feed dispose assembly.
Directly behind upper inside cover.

Also make sure FN21 firmware is at least version 1.18.01.00

IMG_20160121_085925.jpg

Take this advice seriously. This guy knows his stuff. =^..^=

We replaced several clutches dealing with this issue only to find its a temporary fix, or no fix at all. The 3 microswitches i read somewhere else did not fix it either.