Brother International HL-3400CN Service Manual - Page 93

CHAPTER

4

STRUCTURE

OF

SYSTEM

COMPONENTS

TS:

To

maintain

the

temperature

for

fixing

of

the

toner

at

150°C

by

turning

the

thyristor

on

and

off.

TA:

Reference

temperature

(

approx.

185°C)

to

identify

that

it

is

excessively

hot

inside

the

fusing

unit.

When

it

reaches

this

point,

the

relay

RY

turns

off,

the

power

supply

to

the

heat

lamp

is

shut

down

and

the

printer

stops

operating.

TPS:

Limit

temperature

when

the

thermal

fuse

will

start

to

melt

and

shut

down

the

power

supply

to

the

heat

lamp

if

the

temperature

control

circuit

should

break

down.

When

the

thermal

fuse

melts,

the

printer

will

stop

operating.

<Safety

Control

by

Temperature

Control

Signal>

HO:

When

the

THERR

signal

is

input,

the

control

panel

indicates

"HO",

and

the

printer

will

stop

operating.

H2:

If

the

temperature

of

the

fixing

unit

does

not

reach

the

required

point

"T1"

after

a

certain

time,

the

control

panel

indicates

"H2"

and

the

printer

will

stop

operating.

H3:

If

the

"Heater

On"

signal

still

continues

after

a

certain

time,

the

control

panel

indicates

"H3",

and

the

printer

will

stop

operating.

H4:

If

the

temperature

within

the

fusing

unit

becomes

unusually

hot

and

when

ACOFF

signal

is

input,

the

control

panel

indicates

"H4",

and

the

printer

will

stop

operating.

Brother International HL-3400CN Service Manual - Page 93

<Safety

Page 93 highlights