Pre-Transfer Exposure Led; Image Formation Process; Overview - Canon imageRUNNER 7095 Service Manual

Chapter 7

7.1.3 Pre-Transfer Exposure LED

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-trans-
fer 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 poten-
tial (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 ex-
posure LED until the trail edge of the image moves past the point.

7.2 Image Formation Process

7.2.1 Overview

The machine's image formation process consists of the following 8 steps:
Delivery
7-2
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
Static Image Formation Block
2. Primary charging
1. Pre-exposure
8. Drum charging
7. Fixing 6. Separation
flow of paper
direction of drum rotation
3. Laser exposure
4. Development
5. Transfer
Registration
Deck/cassette
F-7-2
Manual feed tray
0010-8037
0011-3423