Gestetner B130 Service Manual page 274

2. DRUM CHARGE
In the dark, the drum charge roller [C] imparts a negative charge to the OPC drum.
(The roller is kept clean by cleaning roller [D].)
3. LASER EXPOSURE
The laser unit, controlled by the FCU, fires a beam [E] at the drum, drawing the
latent electrostatic image on the drum surface. (Exposure by laser dissipates the
local negative charge.)
4. ID (IMAGE DENSITY) SENSOR
The ID sensor [F] periodically measures (a) drum surface reflectivity, and
(b) reflectivity of a test pattern image drawn on the drum. The FCU uses ID sensor
data to adjust charge-roller voltage, and uses both ID sensor data and TD sensor
[J] data to adjust the toner density.
5. DEVELOPMENT
Augers at [G] carry developer (carrier/toner mix) to the magnetic development roller
[H]. The roller creates a developer "brush" that rubs against the drum, causing toner
to adhere to the electrostatic image. (The doctor blade [I] restricts the height of the
"brush." The TD (toner density) sensor [J] measures the ratio of toner in the
developer.)
6. IMAGE TRANSFER
Paper moves between the drum and the transfer roller [K]. A positive charge
applied to the transfer roller pulls toner off the drum and onto the paper, while also
attracting the paper itself.
7. PAPER SEPARATION
Paper is separated from the drum as a result of (a) electrostatic attraction of paper
toward transfer roller, and (b) a high AC voltage applied to the discharge plate [L].
8. CLEANING
The cleaning blade [M] scrapes remaining toner from the drum, and the toner
collection coil [N] retrieves this toner.
9. QUENCHING
Light from the quenching lamp [O] neutralizes the charge on the drum surface.
SM
CÓPIA NÃO CONTROLADA
6-17
CÓPIA NÃO CONTROLADA
COPY PROCESS OVERVIEW
B129 Series/B044 Series