Xerox 7700DX Service Manual - Page 133

Developer Housing

Page 133 highlights

Bead Carryout (BCO) The ATC Sensor magnetically measures the ratio of toner particles to developer carrier beads, not the volume. Under a combination of rare circumstances and component tolerances, it is possible fo rthe carrier beads to be pulled from the Developer during printing; this is called bead carryout or BCO. The Engine Control Board will only auger in the amount of toner to achieve the desired ratio with the remaining carrier beads. If beads are being carried out, then less and less toner will be augered into the Developer Housing. no error message will necessarily be displayed. Printing of that primary color will get progressively lighter and lighter. In such a case, the Developer Housing must be replaced. Opened Developer Housing The Developer/Toner mix should fill the Developer about to the shafts of the two Augers. Developer/Toner should adhere to the Magnetic Roller. Figure 3-6 Developer Housing Print Cartridges The four Print Cartridges in the printer are rarely the cause of any print quality problems. A Print Cartridge is a fairly simple component; there is very little that can go wrong with it. Realistically, the only reason a Print Cartridge should be replaced is for a repeating defect to the cartridge's photoconductive drum. Phaser 7700 Color Laser Printer Service Manual 3-103

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Phaser 7700 Color Laser Printer Service Manual
3-103
Bead Carryout (BCO)
The ATC Sensor magnetically measures the ratio of toner particles to
developer carrier beads, not the volume. Under a combination of rare
circumstances and component tolerances, it is possible fo rthe carrier beads
to be pulled from the Developer during printing; this is called bead carryout or
BCO.
The Engine Control Board will only auger in the amount of toner to achieve
the desired ratio with the
remaining
carrier beads. If beads are being carried
out, then less and less toner will be augered into the Developer Housing. no
error message will necessarily be displayed. Printing of that primary color will
get progressively lighter and lighter. In such a case, the Developer Housing
must be replaced.
Figure 3-6 Developer Housing
Print Cartridges
The four Print Cartridges in the printer are rarely the cause of any print quality
problems. A Print Cartridge is a fairly simple component; there is very little
that can go wrong with it. Realistically, the only reason a Print Cartridge
should be replaced is for a repeating defect to the cartridge’s photoconductive
drum.
Opened Developer Housing
The Developer/Toner mix should fill the Developer
about to the shafts of the two Augers.
Developer/Toner should
adhere to the Magnetic
Roller.