Phaser 6250 Jams at fuser every 4th page

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Xerox Phaser 6125 printer. told wrong?
get it serviced
and watch them, do this, cleaned all paths and blew out all sensors
cleaning is hard work watch them do it all
how and materials used
call them. now.
or read page on fuser jam here/.
pdf page 95

https://www.manualslib.com/manual/339573/Xerox-Phaser-6125.html?page=95#manual

using Xerox parts or clones, fuser and cartridges./

you must configure the page size, because the configuration jams have a page shorter than the product that you put to print.

Paper type set correctly? Does the paper enter the fuser? If not, the fuser drive has failed, replacing the fuser may correct it.

Clean the rollers. If that does not work, replace the rollers.

Have you tried a different type/grade of printing paper?

This jamming has to do with third-party toner cartridges being used. I had this problem using Xerox toner cartridges and found that I would have no jamming if I used at least 2 hp-brand toner cartridges and the rest Xerox. I then used a different brand of 3rd party toner cartridges that would not jam as long as just the black cartridge was a genuine HP black toner cartridge. This issue has been confirmed even by the manufacturers of the generic toner cartridges. Hope that helps!

I can tell you "exactly" where your jam is !

If you open the top cover and remove the imaging unit. Look straight down, and you will see a black rubber roller about 8 inches long. this is the registration roller. If you remove the four screws (two on the left side, one in the middle, and one on the right) and gently lift up your wrinkled paper will be right there. Since your are not replacing the registration assembly you do not need to remove the two connectors that attach to the main board from the registration assembly. Just remove the paper, reseat unit, and put back screws. There is a test to see if your unit has the fix that gives the drive assembly a little more power to aviod jams in the future. This is a software fix.
I believe it's available on the xerox website as a postscript snippet. xx.ps

There is a firmware upgrade for the 6250 to prevent it from jamming at the fuser.

Firmware upgrade is here:

http://www.support.xerox.com/go/getfile.asp?Xlang=en_US&XCntry=USA&objid=48103&EULA=0&prodID=6250&Family=Phaser&ripId=&langs=English%20(US)&plats=Windows%20XP&Xtype=download&uType=

If you are getting a lot of jams in the fuser then there is a problem in the fuser unit !
Is it jamming like an accordion? if Yes, then the problem is w/ the little fingers in the fuser, they are worn and need to be replaced. The rollers in the fuser should be shiny and smooth if not they ca also cause jams.
What black thingy are we talking about and where? if it's the fuser rollers ( where the paper exits and gets hot then try cleaning w/reg soap & water rag then wipe off.

How Brave is Jan?

Doubt it be the fuser(100 000life), "just magenta dots".... fuser would be "all smudged" or "black marks" , "the print rubs off" , "paper is creasing or jamming"

Can prove it by stopping a print (open door) when paper is1/2 way threw machine, you need to stop it before it goes threw the hot bit, so you can tell if the hot bit (fuser) puts the marks on the paper.

Transfer roller one would expect to effect whole print Smudged/Faint,uneven density

It will be the imaging unit ( 30 000 pagelife Ouch$ ) or possible leaking toner (if aftermarket)

Remove imaging unit and inspect film you should find image of lines, dots are usually chips or sticky stuff on drum surface, carefull no oily human fingers on surface please.

When stopping machine mid print and perfecting your timing, pull out the imaging unit and look at replica of your print notice if marked and where.

Hope this helps