Brother International HL-3400CN Service Manual - Page 64

HL-3400CN

SERVICE

MANUAL

2

Exposing

The

exposing

process

means

that

the

OPC

belt

surface

is

exposed

to

the

laser

beam

to

form

an

electrostatic

latent

image.

(1)

Structure

of

laser

unit

i)

The

laser

unit

is

located

as

shown

in

Fig.4-8.

ii)

The

source

of

the

laser

beam

is

a

semiconductor

laser.

iii)

The

laser

light

is

scanned

onto

the

OPC

belt

by

converting

the

laser

light

to

a

beam

of

light

through

the

lens

and

reflective mirror

to

form

an

electrostatic

latent

image.

(2)

Process

of

exposing

(Refer

to

Fig.4-13.)

i)

The

OPC

belt

surface

has

been

charged

to

the

potential

-Vo(V)

in

the

charging

process.

ii)

The laser

light

is

scanned

at

right

angles

to

the

forward

direction

of

the

OPC

belt.

iii)

High

speed

switching

of

the

laser

is

made

according

to

the

transmitted

image

data.

iv)

The

charge

of

the

areas

radiated

by

the

laser

light

is

reduced

to

the

potential

-

VR(V).

v)

An

invisible

electrostatic

latent

image

is

formed

on

the

OPC

belt

as

shown

in

Fig.

4-13.

V

C

0 0

O

-V

R

'D

GI'

-V

0

,,r

i

0

,

0

0

0 0

I

O

'D

1

1

1

1

1

1

CD

Charging

Exposing

Fig.

4-13

4-13

Brother International HL-3400CN Service Manual - Page 64

HL-3400CN, SERVICE, MANUAL, Charging, Exposing

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