We have a Phaser 7800 DX that we've always run non-OEM toner catridges in to save money.
For some time, the Yellow and Cyan catridges, no matter how many we buy and replace, will switch between full/empty/almost empty regardless of how much toner is left. Often they will last less than a week before reading "Empty".
Our first reaction is to blame the off brand toner, but the Cyan and Black catridges seem to have no problems. Also, all 4 cartridges will become very messy, with toner powder spreading out inside the machine after installation. I assume problem would continue even with Xerox brand toner.
Could this in fact be a problem caused inside the machine; developer perhaps? Or a problem related to toner chips? Please alert me to a way to properly diagnose the issue. Thanks!