Canon 7086 Series Service Manual - page 248
Chapter 7
7-2
F-7-1
7.1.3 Pre-Transfer Exposure LED
0010-8037
iR7105 / iR7095 / iR7086
The machine's processing speed is set to 500 mm/sec, thus enabling 105 prints/min (A4, 100%; iR7105). To make up for a drop in charging, the machine uses a
photosensitive drum capable of a high charging efficiency and a pre-exposure lamp emitting light of a short wave length (660 mm). A high process speed can also
adversely affect static separation, which would lead to poor separation if left alone, and pre-transfer exposure LED is used to ensure correct separation.
Reference:
Pre-Transfer Exposure
Function: In the initial state of the transfer process, the machine decreases the photosensitive drum potential (background potential) in advance so as to reduce the
static bonding between the photosensitive drum and the transfer medium, thus facilitating separation.
Timing: 100 msec before the lead edge of the image reaches the point of activation of the pre-transfer exposure LED until the trail edge of the image moves past
the point.
7.2 Image Formation Process
7.2.1 Overview
0011-3423
iR7105 / iR7095 / iR7086
The machine's image formation process consists of the following 8 steps:
step 1
pre-exposure
step 2
primary charging (positive DC)
step 3
laser exposure
step 4
development (AC + positive DC)
step 5
transfer (negative DC)
step 6
separation (AC + positive DC)
step 7
fix
step 8
drum cleaning