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3-4

                   Paper size detecting sensor

            S1             S2           S4

Ledger/A3          ON            OFF        ON

Legal/B4            ON            ON          ON

Letter/A4            ON            OFF        OFF

Letter-R/A4R      OFF           ON          OFF

Invoice/A5          OFF           OFF        OFF

3)

Detecting the paper

• Paper in the sheet bypass tray is detected by the sheet bypass paper detecting

sensor. When paper is detected, the paper detecting sensor turns off, and

when no paper detected, the sensor turns on.

4)

Detecting sheet bypass paper size

• The paper size for the sheet bypass is detected by a matrix of sheet bypass

paper size sensors which are installed on the sheet bypass tray.

• When setting the paper in the sheet bypass tray and adjusting the paper guide,

the matrix is as follows.

S1/S2

S4

Clutch

Middle gear

Registration
roller gear

Registration
roller clutch

Registration
roller

Paper pass
sensor

Cleaning sheet

DFP roller

Paper feed roller

Pick-up roller

Solenoid

Clutch gear

Paper
detecting sensor

Middle
roller
(upper)

Middle roller (lower)

Sheet
bypass
unit

Middle gear

Main motor

Pulley 2

Pulley 1

Sub Assemblies

3-5

(2)

Paper feed unit

1)

Construction of paper feed unit

• The construction of paper feed unit is as follows.

Part description

Functions

1

Paper transfer roller

Transfer the paper from paper feed cassette.

2

Paper feed roller

Feed the paper.

3

Paper feed solenoid

Drive the paper to paper transfer roller.

4

Paper feed clutch

Drive paper feed roller and others.

5

Paper pass sensor

Detect the paper passage.

6

Middle roller

Drive the paper to machine.

7

Double feed

Prevent double paper feed.

prevention roller

8

Paper detecting sensor

Detect the paper in paper feed cassette.

9

Paper level upper limit sensor

Detect the upper limit position when lifting the paper

in paper feed cassette.

3-6

2)

Paper feed unit operation

• By pressing the Print key, the electromagnetic clutch turns on, and the

revolution of the main motor is transmitted to the idle gear through respective

gears and belt.  The idle gear which is connected to the middle roller gear

rotates.

• The paper feed solenoid turns on, pushing the pick up roller to the paper. The

paper feed clutch turns on to rotate the pick up roller and paper feed roller,

which feeds the paper in the cassette to the middle roller.

• When multiple sheets are fed, the rotating force of the double feed prevention

roller is under specific torque, and the double feed prevention roller rotates in

reverse. As a result the bottom sheet is put back in the drawer.

    (The torque is determined by torque limiter.)

• The paper pass sensor checks paper feed from the drawer. If it does not

detect the paper passing in a specified time,  the Retry system is employed.

• The paper arrives at the middle roller, and is detected by a paper pass sensor

on the way to the timing roller. After a specified time, it touches the timing

roller and waits there.

• After a specified time following the optics system start, the optics home position

sensor detects the passing of the optics system (full-speed unit), the timing

clutch turns ON and the timing roller rotates. Accordingly, the paper is fed into

the machine, and the registration of original and copy paper is achieved.

Paper feed clutch

Middle roller

Paper pass sensor

Middle roller

Paper feed solenoid

Pick-up roller

Paper limit sensor

Paper detecting sensor

Paper feed roller

DFP roller

Sub Assemblies

3-7

3)

Paper drawer lift mechanism

• When inserting the paper drawer, the lift lever connects with the coupling

which drives the the machine side lift lever. Next, the lift motor rotates, and it's
drive is transmitted to the lift lever driving gear via respective gears, and
rotates the lift lever to lift up the drawer bottom plate.

• When the bottom plate (and papers) have been lifted up, the bottom plate

upper limit sensor on the paper feed unit side turns on and the revolution of
the lift motor stops to keep the paper at the specific position.

4)

Detecting paper

• The paper detecting sensor is turned ON by  paper in the paper drawer.

When there is no paper in the drawer, the paper detecting sensor turns off by
falling into the groove in the drawer bottom plate.

• As paper is used, the drawer bottom plate is lifted up. At a specific level,

paper level warning sensor turns on to detect  a low paper condition.

Pick-up roller

Paper upper limit
sensor

Paper level sensor (located
on the copier frame)

Coupling

Bottom plate

Paper detecting sensor

Lift motor