Ricoh A028 Service Training Manual page 91

1 July 1994
Cleaning method
Any toner remaining on the OPC receives a positive
charge from the pre-cleaning corona. The toner is
attracted to the cleaning carrier which has a negative
charge. Furthermore, negative cleaning bias is applied
to the cleaning roller, and the remaining toner is
attracted to the carrier on the cleaning roller.
Toner collecting mechanism
An 8-pole magnet is provided in the cleaning roller to
attract the cleaning carrier to the surface of the cleaning
roller. The cleaning carrier attracted to the cleaning roller
is cut to a specified height by the doctor blade. Then the
cleaning carrier contacts the photoconductor as the
cleaning roller rotates in a direction reverse to the
photoconductor.
The positively charged toner is attracted by the cleaning
roller through the cleaning carrier. Then, the toner on the
cleaning roller is collected by the scavenging roller
because the roller is supplied with higher bias voltage
than that of the cleaning roller.
The scavenging blade cleans toner from the surface of
the scavenging roller. The toner scraped from the roller
drops to the collecting coil, and rotation of the coil feeds
the toner to the rear.
The toner is sent to the collecting tube through the used
toner outlet pipe. A coil is also provided in the collecting
tube and is rotated by the main motor via the friction
roller, etc. Next, the toner is sent to the toner cartridge.
Cleaning roller
Cleaning
carrier
Toner
Scavenging roller
Scavenging blade
Friction roller
Friction drive disk
Collecting tube
Sensor disk
2-55
Cleaning
Cleaning bias
Photoconductive
layer
Conductive layer
Scavenging bias
(--10µA)
Cleaning bias
(--20µA)
Cleaning roller
Bronze seal
Scavenging roller
Toner collecting coil
Used toner
outlet pipe
Toner cartridge
Cleaning coil sensor