HP LaserJet Enterprise M552 - Intermediate transfer belt (ITB) unit; Primary-transfer roller engagement and disengagement control

Intermediate transfer belt (ITB) unit
The ITB unit accepts the toner images from the photosensitive drums and transfers the completed image to
the paper. The ITB unit has the following main components:
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Intermediate transfer belt (ITB)
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ITB-drive roller
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Primary-transfer roller
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ITB cleaner
Drum motor 3 drives the ITB drive roller, which rotates the ITB. The motion of the ITB causes the primary
transfer rollers to rotate. The ITB cleaner cleans the ITB surface.
Figure 1-26 ITB unit
ITB cleaner
ITB
Drum motor 3
M3
SR5
SL1
M4
Toner collection unit
Toner collection unit full
sensor
Fuser motor
Primary transfer roller
disengagement solenoid
ITB drive roller
Primary transfer roller
DC controller
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ITB
Drum motor
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Fuse
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Primar
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Primary-transfer roller engagement and disengagement control
Depending on the requirements of the print job, the primary-transfer rollers engage with the ITB so it can
receive toner from the photosensitive drums. The primary-transfer rollers have three engagement states.
Table
1-16 Primary-transfer roller engagement states
All rollers disengaged The ITB is disengaged from all the four photosensitive drums. This state is the home
position for the ITB unit.
All rollers engaged The ITB is engaged with all four photosensitive drums. This is the state for full-color
printing.
Black roller engaged The ITB is engaged with only the black photosensitive drum. This is the state for black-
only printing.
ENWW Engine laser/scanner system 45