2. Developing section
1) General descriptions
(1) Two-component developer
The developer is composed of toner and carrier.
Carrier serves as a medium for attaching toner onto the electrostatic image on the photoconductor drum.
By stirring toner and carrier, they are rubbed to be charged positive
(+) and negative
Since developer will deteriorate to degrade copy quality, it should be replaced regularly.
(2) Two-component magnetic brush development
The rotatable
Carrier forms a magnetic brush on the sleeve surface by magnetic force to attach toner onto the electrostatic image on the photoconduc- tor drum.
(3) Developing bias
When the photoconductor is charged and exposed to light (ex- posure), the surface potential (voltage) of the photoconductor will not be lost completely. (The residual potential remains.)
Toner is attracted to the photoconductor by this residual potential, dirtying the photoconductor. As a result, a dirty copy of white back- ground is generated.
To prevent against this, a voltage of the same polarity and higher than the residual potential is applied to the MG roller, preventing toner from being attached to the photoconductor surface.
Residual potential < DV BIAS
MG roller
DV BIAS
Toner 
Carrier
Developing bias voltage
(4) DV harness
The toner density sensor, the developing bias, and the developing
unit identification resistance harness.
(For details, refer to [6] DISASSEMBLY AND ASSEMBLY.)
(Viewed from the rear of develoing unit)
DV harness connector
(Details of DV harness connector)
For color identification | For bias |
GND
Resistor
*For toner density sensor
GND | VB |
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*Resistance value is identified by color
2) Basic composition
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1 | Magnet roller |
| Forms a magnetic brush of carrier | |||
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2 | Developing doctor blade |
| Limits the height of the magnetic | |||
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| brush. |
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3 | Developing MIX roller |
| Stirs carrier in the developing unit | |||
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| and distributes toner evenly. |
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4 | Toner transport roller |
| Transport toner sent from the | |||
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| toner hopper unit to the stirring | |||
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5 | Toner density sensor |
| Senses | toner | density | in |
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| developer. |
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