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AL-1611/AL-1622

OPERATIONAL DESCRIPTIONS

6 – 5

Before the drum rotation is stopped, the semiconductor laser is radiated

onto the drum to reduce the electrical resistance in the OPC layer and
eliminate residual charge, providing a uniform state to the drum surface

for the next page to be printed.When the electrical resistance is

reduced, positive charges on the aluminum layer are moved and neu-
tralized with negative charges on the OPC layer.

The Scorotron charger functions to maintain the surface potential of the

drum even at all times which. It is used to control the surface potential

regardless of the charge characteristics of the photoconductor.

A screen grid is placed between the saw tooth and the photoconductor.
A stable voltage is added to the screen grid to maintain the corona cur-

rent on the photoconductor. As the photoconductor is charged by the

saw tooth from the main corona unit, the surface potential increases.
This increases the current flowing through the screen grid. When the

photoconductor potential nears the grid potential, the current turns to

flow to the grid so that the photoconductor potential can be maintained
at a stable level.

The print pattern signal is converted into an invisible image by the semi-
conductor laser using negative to positive (reversible) developing

method. Therefore, if the developing bias is added before the drum is

charged, toner is attracted onto the drum. If the developing bias is not
added when the drum is charged, the carrier is attracted to the drum

because of the strong electrostatic force of the drum.

To avoid this, the process is controlled by adjusting the drum potential
and the grid potential of the Scorotron charger.

Voltage added to the screen grid can be selected, high and low.To

make it easily understood, the figure below shows voltage transition at

the developer unit.

1) Because the grid potential is at a low level, the drum potential is at

about -400V. (Carrier may not be attracted though the carrier is

pulled towards the drum by the electrostatic force of -400V.)

2) Developing bias (-400V) is applied when the photoconductor poten-

tial is switched from LOW to HIGH.

3) Once developing bias (-400V) is applied and the photo conductor

potential rises to HIGH, toner will not be attracted to the drum.

The reverse sequence takes place.

The developing bias will be lost if the power supply was removed during

print process. In this event, the drum potential slightly abates and the

carrier makes deposits on the drum because of strong static power. To
prevent this, the machine incorporates a function to retain the develop-

ing bias for a certain period and decrease the voltage gradually against

possible power loss.

Normally, the developing bias voltage is retained for a certain time
before the drum comes to a complete stop if the machine should stop

before completing the normal print cycle. The developing bias can be

added before resuming the operation after an abnormal interruption.
Therefore, carrier will not make a deposit on the drum surface.

The image data sent from the MCU (image process circuit) is sent to the

LSU (laser unit), where it is converted into laser beams.

The LSU unit is the writing section of the digital optical system.The

semiconductor laser is used as the light source, and images are formed

on the OPC drum by the polygon mirror and fq lens, etc.

The laser beams are passed through the collimator lens, the cylindrical

lens, the polygon mirror, the fq lens, and the mirror to form images on
the OPC drum in the main scanning direction. The laser emitting PWB

is provided with the APC (auto power control) in order to eliminate fluc-

tuations in the laser power. The BD PWB works for measurement of the
laser writing start point.

Semiconductor laser

0

START

STOP

Print potentioal

Toner attract
potential

2)

3)

1)

Low

4)

High

Drum potential

Developing bias

Time

1

Semiconductor laser

Generates laser beams

2

Collimator lens

Converges laser beams in parallel

3

Polygon mirror, 
polygon motor

Reflects laser beams at a constant rpm

4

BD (Mirror, lens, PWB) Detects start timing of laser scanning

5

f

θ

 lens

Converges laser beams at a spot on
the drum.
Makes the laser scanning speeds at
both ends of the drum same as each
other. (Refer to the figure below.)

6

Laser emitting PWB

Emits laser beams according to the
image data.

6

5

2

1

3

4

AL-1611/AL-1622

OPERATIONAL DESCRIPTIONS

6 – 6

Makes the laser scanning speeds at both ends of the drum same as
each other.

a 

≠ 

b 

≠ 

c

a

b

c

d = e = f

d e

f

1

No. 1 cassette paper feed roller (Semi-circular roller)

Picks up paper from No. 1 cassette.

2

Main motor

Drives the process section and the paper transport section.

3

No. 1 cassette paper feed solenoid

Rotates and controls No. 1 cassette paper feed roller.

4

No. 1 cassette paper feed roller clutch

Drives No. 1 cassette paper feed roller.

5

Manual paper feed roller

Picks up paper from the manual paper feed tray.

6

Manual paper transport roller

Transport paper which was picked up from the manual paper feed tray.

7

Manual paper feed roller clutch

Drives the manual paper feed roller.

8

Manual paper transport roller clutch

Drives the manual paper transport roller.

9

Manual paper feed roller solenoid

Rotates and controls the manual paper feed roller.

10

Manual paper transport roller solenoid

Rotates and controls the manual paper transport roller.

11

Resist roller

Takes synchronization between the paper lead edge and the image lead edge.

12

Resist roller clutch

Drives the resist roller.

13

Resist roller solenoid

Rotates and controls the resist roller.

AL-1611/AL-1622

OPERATIONAL DESCRIPTIONS

6 – 7

This machine allows two ways of paper feed system: cassette paper

feed and manual paper feed.
The cassette of universal type is employed to hold 250 sheets. The

front loading system allows to attach or detach the cassette from the

front of the machine.
Paper size can be selected by the user.

Since this model is not equipped with the automatic paper select func-

tion, paper size detection is not performed.

Select the cassette and press the START button, and the paper feed
roller solenoid will be turned on and the paper feed clutch will be

released.

The drive power of the main motor is transmitted through the paper feed

roller clutch to the paper feed roller, rotating the paper feed roller and
feeding paper.

Select the manual paper feed tray and press the START button, and the

manual paper feed roller will be turned on to bring the paper feed roller

in contact with paper and lift the shutter simultaneously.
The drive power of the main motor is transmitted through the manual

paper feed roller clutch to the manual paper feed roller, rotating the

manual paper feed roller and feeding paper. 

In order to make synchronization between the paper lead edge fed from
the paper feed port and the image lead edge, the roller is kept station-

ary for a certain time after the paper reaches at the roller towarp the

paper a little.
When the paper is warped to a certain level, the resist roller solenoid is

turned on to release the resist roller clutch.

The drive power of the main motor is transmitted through the resist
roller clutch to the resist roller, rotating the resist roller and feeding

paper.

A pressure roller is used for the heat roller and a silicone rubber roller is

used for the lower heat roller for better toner fusing performance and
paper separation.

Four separator pawls are used on the upper heat roller. The separator

pawls are teflon coated to reduce friction with the roller and prevent a

smear on the paper caused by the separator pawl.

1) The heater lamp, thermistor, main PWB, DC power supply PWB,

and triac within the power supply unit are used to control the tem-

perature in the fuser unit. To prevent against abnormally high tem-

perature in the fuser unit, a thermostat is used for safety purposes.

2) The surface temperature of the upper heat roller is set to 180°C ~

195°C. The surface temperature during the power save mode is set
to 100°C.

5

4

3

2

1

8

6

7

1

Before-fusing 
paper guide

Guides the paper transported from the process
section to the fusing unit.

2

Upper heat 
roller

Applies heat and pressure to the paper to fuse.

3

Thermistor

Detects the surface temperature of the upper
heat roller.

4

Thermostat

Stops power supply to the heat roller in case of
an abnormally high temperature of the heat
roller.

5

Separation 
pawl

Separates the print paper from the upper heat
roller.

6

POD1

Detects that the paper has been transported
from the fusing section.

7

Heater lamp

Heats the heat roller.

8

Lower heat 
roller

Applies a pressure to the paper together with
the upper heat roller.

2

7

5

8

4

3

Safety device
(thermal breaker, thermal

fuse)

Triac (in the
power supply unit)

Heated  by the

heater  lamp.

(950W )

The surface temperature

of the  upper hea t roller

is sensed by the thermistor.

Level of the thermistor is
controlled by the main PWB.

With the signal from the
main PWB, the triac  is

controlled on and off.

(power  supply PWB )

AL-1611/AL-1622

OPERATIONAL DESCRIPTIONS

6 – 8

3) The self-check function comes active when one of the following

malfunctions occurs, and an "H" is displayed on the copy quantity

display.

Fusing temperature error value

H4 (Low temperature error)

• During machine operation 

The case where the fusing temperature (thermistor output value)

does not reach 155°C within 55 sec from lighting of the heater

lamp. (If the toner motor rotates for 10 sec or more continuously
when starting the machine, the case where the fusing tempera-

ture does not reach 155°C within 60 sec.)

• During printing

When the fusing temperature (thermistor output value) falls below

145°C. 

H3 (High temperature error)

Fusing temperature (thermistor output value) of about 220 to 240°C

(varies depending on the resistance.)

Since the upper heat roller is conductive when copy paper is highly

moistured and the distance between the transfer unit and the fusing unit
is short, the transfer current leaks through the copy paper, the upper

heat roller and the discharging brush.

To prevent against this, a resistor of 150MOhm is provided between the
frame and the discharge brush to minimize leak current and improve

transfer efficiency.

When a document is set on the document set tray in the auto mode of

paper/copy magnification ratio selection, the document size is detected
to perform the auto selection function of paper and the copy magnifica-

tion ratio according to the detected document size. 

When documents of different sizes are mixed and set on the tray, the

max. size is detected. The document width is detected by the document
width sensors (W1, W2, W3), and the document length is detected by

the document length sensors (L1, L2) to determine the document size. 

The document size judgment is made after a certain time from when the

document set sensor (W0) detects the document.

Note: Sensor ON: 

F

OFF: 

D

 

 

1) Document set (Document set sensor ON)

3) Copy start (Machine)

4) SPF motor ON

5) Pickup solenoid ON

6) Pickup roller rotation

7) Paper feed roller rotation

8) Paper entry sensor detects paper presence.

9) PS roller rotation

10) Copy operation (Machine)

11) Transport roller  rotation

12) Paper exit roller rotation

13) Document exit

YES

14) Next document

 NO 

2) Document size detection (The document width is detected
    with  document width sensors W1, W2, and W3, and the
    document length is detected with document length sensors
    L1 and L2.)

15) SPF motor OFF

Document size 

and set direction

Document width sen-

sor

D o c u m e n t
length sensor

W1

W2

W3

L1

L2

AB series

A5

F

D

D

D

D

B5

F

F

D

D

D

A5R

D

D

D

D

D

A4

F

F

F

D

D

B5R

D

D

D

F

D

A4R

F

D

D

F

D

8.5" x 13"

F

D

D

F

F

B4

F

D

D

F

F

A3

F

F

F

F

F

 Inch series

8.5" x 5.5"

F

D

D

D

D

8.5" x 5.5"R

D

D

D

D

D

11" x 8.5"

F

F

F

D

D

11" x 8.5"R

F

D

D

F

D

8.5" x 13"

F

D

D

F

F

8.5" x 14"

F

D

D

F

F

11" x 17"

F

F

F

F

F