Less skew from HCT tray 5 on HP Color LaserJet Flow E87640

[HeadTurd]

Customer runs 8.5 x 11 MICR checks exclusively and must be within certain tolerances. Trays 2-4 run fine but tray 5 eventually starts drifting an develops a skew. It is within HP specs but not the customers. Works for a while after merge unit, and feed tires are replaced but then begins again after 200k or so. They run about 100k/ month. I want to create a custom paper profile for them and wondering what settings would give me the most pre- registration buckle and keep this skew at bay. 

Any HELP appreciated, its becoming a PITA!!!!

[GaryL1]

Hey, I know this may be slightly different, but we had a skew from the HCI tray.  E87650,  Never from the upper cassettes.  The tech even swapped out the HCI assembly with no luck.  So slightly out that you had to hold two sheets up to a bright light to see the differences.  Although I had my own doubts, I suggested he replace a registration assembly.  He disagreed, but it's an easy to change part and around $50, so we had one in 2 days  After it was installed he waited and waited for the skew.  It never was.  He went back often and saw samples that it ran perfectly aligned.

That was our 4th registration we replaced, so something happened to that batch OF UNITS