Brother HL-4000CN, Service Manual

Page: 93 / 345

III-15
1.3.11 Cleaning (general)
In the cleaning (general) process, toner stored in the IDT 1 cleaner and IDT 2 cleaner
after the finished toner image is transferred onto the paper and the toner remaining on
the transfer roll cartridge are removed.
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The toner not completely transferred in the "secondary transfer" and "tertiary
transfer" processes is held temporarily in the IDT1 cleaner and IDT2 cleaner. Also,
the toner of which polarity is reversed and returned to the drum is held in the
refresher. Further, the toner that passes the refresher may stick to the HTC.
These toners are cleaned at the completion of the printing. The recovery method is
different between the toner held in the IDT1 cleaner and IDT2 cleaner and the toner
held in the refresher and HTC.
1) IDT1 cleaner and IDT2 cleaner
High voltage equivalent to the voltage at the printing transfer is applied to the IDT1,
IDT2, and transfer roll cartridge. The toner (negative polarity) remaining in the IDT1
cleaner and IDT2 cleaner are moved to the IDT1 and IDT2 electrically by
transforming the IDT1 cleaner and IDT2 cleaner to 0V. Then, in the same manner
as in the printing transfer, the residual toner is collected to the transfer roll cartridge
surface by potential difference between IDT1, IDT2, and transfer roll cartridge.
IDT1
IDT1
HVPS
IDT2
HVPS
IDT1 Cleaner
IDT1 Cleaner
Transfer
Roll
Cartridge
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HVPS
Scraper
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IDT2 Cleaner
: Positive electric charge
: Toner
Fig.3-22