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[9] TRANSPORT/FUSING SECTION
1. General
The SD-2050 allows transport of paper of max. A3 (11" x 17") and
min. A5 (8 1/2" x 5 1/2").
After images are transferred on the paper, the paper is separated
from the drum and transported to the fuser section by rotations of the
resist roller and the transport belt.
The paper separation sensor (PSD) is provided at the transport sec-
tion. This sensor (PSD) is used to sense paper separation and for
drive timing of the duplex gate solenoid (DGS) after fusing.
2. Basic composition and functions
(1) Transport section
1 Transport belts (2pcs)
The transport belts are provided with notches to hold the rear and
of the paper.
Paper
Transport belt
2 Separation sensor (PSD)
This is a transmission type sensor, and is attached to the main
body chassis.
3 Suction fan motor and ozone filter
Ozone generated in the process high voltage section is absorbed
and decomposed by the filter.
(2) Fusing section
1 Upper heat roller
The upper heat roller is teflon-coated. (Reversed crown shape)
2 Lower heat roller
A silicone rubber roller is used. (Crown shape)
3 Upper cleaning roller
The upper cleaning roller is impregnated with silicone oil to
remove dirt on it and to provide better separation effect, lengthen-
ing the heat roller lifetime.
4 Separation pawl
The upper heat roller is equipped with four pawls which are teflon
coated to reduce friction.
The lower heat roller is equipped with four pawls.
5 Upper/lower separation function
The upper and lower heat roller sections are separated by rotating
operations with the fulcrum screw as the center, providing better
serviceability.
6 Drive system division
The fusing unit is normally rotated by the main drive unit.
The spring clutch is provided in the main drive gear to allow
manual rotation of the fusing unit in case of a paper jam.
[10] HIGH VOLTAGE SECTION
1. General
There are three kinds of coronas; the main corona, the transfer
corona, and the separation corona. The main corona employs the
scorotron system, where the drum surface is evenly charged with
negative charges controlled by the screen grid between the corona
and the drum. The transfer corona is used to transfer toner images on
the drum to the copy paper. A high, negative voltage is applied to the
rear side of the paper. The separation corona applies AC corona to
the copy paper to eliminate potential difference with the drum to allow
separation of the paper.
2. Basic composition
(1) Main (charging) corona – High voltage
transformer (MHVG)
(Electrode sheet front-rear balance difference: max. 10µA)
Feeding direction
Standard mode
Photo mode
TSM mode
(2) Transfer corona – High voltage transformer
(THVG)
–62µA (Electrode sheet front-rear balance difference: max. 5µA)
(3) Separation corona – High voltage transformer
(SHVG)
AC5.8KV ±0.15KV
9 – 1
Grid voltage
Developing bias voltage
–730V
–450V
–200V
–625V
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