There are two ways to look at the problems with the Xerox 700: 1) Xerox over-marketed the machine relative to it's engineered capabilities, or 2) Engineering flaws have caused it to fall short of its intended capabilities. Either way, it's a sad joke of a machine when compared to the competitors it's priced against.
We've been running one for more than two years, and I'd say the entire internals of the machine have been replaced at least three times. As stated by others, the biggest flaw is with the toner delivery system/developer housings. Here's the issue in a nutshell: toner is what the little metal developer balls in the housing use for lubricant, and if you run too much heavy coverage, the developer housings will require a constant stream of toner from the toner cartridges to stay lubricated and deliver toner to the sheet. The toner cartridges have a little tiny door that opens and dispenses toner to the developer housings, so when the housings need lots of toner due to heavy coverage, they have a hard time getting enough through the little tiny door and have to continue to make repeated requests for toner. Each one of these requests works the developer housing gears hard and the toner delivery motors hard, wearing them out much more quickly than they should, and they still don't wind up getting enough toner, wearing out the coating on the metal developer balls, necessitating the replacement of the housings. We run a lot of heavy coverage and we've had our housings replaced a dozen times. The tech suggest replacing the toner cartridges when they're less than 50% full since that exacerbates the problem with not enough toner getting though the cartridge door as the cartridge gets emptier. This is but one of many absurdities one will encounter when operating a Xerox 700.
I suspect the modifications that are being reported are attempts to retrofit the 700 with any modifications that may have been made on the new 700i/770. I haven't been able to get any confirmation that the toner delivery system has been improved (Xerox sales claims the issue has been addressed though "software improvements"), so if anyone has any information on this, please share it.
