Ibt-I - Epson ColorPage EPL-C8000 Service Manual

EPSON EPL-C8000

2.5.8 IBT-I

1. Transfer Assembly
The Transfer Assembly consists of the following components:
n 1st BTR
n Back Up Roll
n Contact Roll
(a) The 1st BTR (First Bias Transfer Roll) is a conductive roll, facing
the drum. (The IBT Belt Assembly is in the middle.) The 1st BTR
transfers the toner image on the drum to the IBT Belt Assembly.
(b) The Contact Roll is a metal roll (small diameter). It is in contact
with the Back Up Roll and provides the 2nd transfer voltage to
the Back Up Roll.
(c) The Back Up Roll is a conductive roll, facing (from inside) the
2nd BTR. (The IBT Belt Assembly is in the middle). When the
paper passes through, the Back Up Roll provides the 2nd
transfer voltage to the paper from the inside of the IBT Belt
Assembly.
(d) The IBT Drive Roll Assembly transfers the driving force of the
Process Motor Assembly to the IBT Belt Assembly. (The
Process Motor Assembly receives the driving force from the
Process WDD Assembly.)
(e) The silver marks (TRO marks) is pasted at the rear end of the
IBT Belt Assembly. This is because the toner images transferred
onto the IBT Belt Assembly must match precisely. The TRO
Sensor detects this mark every time the IBT Belt Assembly
makes one rotation. When the sensor detects the mark, the
system waits for a predetermined period and then generates a
TRO signal (which indicates the reference point and the image
transfer reference point to form an image.) The IBT Belt
Assembly has two TRO marks. As a result, every time the
Chapter 2 OPERATING PRINCIPLES
n IBT Drive Roll Assembly
n TRO Sensor
n IBT Belt Assembly
Process Motor runs, the transfer reference marks are alternately
detected. This prevents the image from being transferred onto
the same location on the belt all the time—something that leads
to image degradation.
(f) A one-color toner image on the drum is transferred onto the IBT
Belt Assembly. This process is repeated four times (for four
colors). At the end, a 4-color overlaid toner image has been
formed on the IBT Belt Assembly. When the complete toner
image is formed on the belt, the 2nd BTR provides negative
transfer voltage to the belt and the belt transfers the image (of 4-
color toner) onto the paper (2nd transfer).
Figure 2-33. IBT-I
Rev. B
2-33