Brother HL-4000CN Service Manual page 89

1.3.5 Secondary transfer (IDT 1 -> IDT 2)
In the secondary transfer process, the toner image formed on the IDT 1 surface is
transferred onto the surface of the IDT 2 (Intermediate Drum Transfer 1: intermediate
transfer roll 2).
Two color toner image transferred onto the 2 IDT 1 is transferred to the IDT 2. Thus, 4
color toner image are compiled on the IDT 2 as finished toner image.
IDT 2 is a conductive roll and receives supply of positive high voltage from HVPS.
Both the IDT 1 and IDT 2 are positively charged. Voltage is higher on the IDT 2 and
toner image is attracted to the IDT 2 surface and transferred onto the IDT 2.
1.3.6 Cleaning (IDT 1)
In the cleaning process (IDT 1), toner remaining on the IDT 1 after the toner image is
transferred to the IDT 2 is temporarily stored in the IDT 1 cleaner.
The IDT 1 cleaner receives positive high voltage from the HVPS with a conductive
roll brush.
The IDT 1 cleaner is placed in contact with the IDT 1 at the position through which it
passes after the toner image having been transferred from the drum is transferred to
the IDT 2. Toner remaining on the IDT 1 is electrically scraped and stored.
The toner stored is collected upon completion of printing or at the time of cleaning
cycle. (Refer to1.3.11 Cleaning (general).)
IDT1 Cleaner
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HVPS
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IDT1
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IDT2
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IDT1
IDT1 Cleaner
Fig.3-18
III-11
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: Positive electric charge
: Toner
HVPS