User Guide

If an original is over a sensor, the light reflected by the original is received by the

original detection circuit so that the output of the detection circuit is specific regardless

of the angle of the copyboard cover.

If no original is over the sensor, on the other hand, the output immediately after PS5

turns on is small. The output increases thereafter when the copyboard cover is fully

closed, since the detection circuit will receive the light reflected by the copyboard cover

sheet.

As such, the DC controller assumes the presence of an original at each point if the

output of the detection circuit remains unchanged and assumes the absence of an

original in response to a change in the output.

This type of detection enables identification of the size of a black original as well.

Reference:

1. If the original is thick and the copyboard cover cannot be closed fully even after

PS5 has turned ON, the output level of the sensor will not change. As such, if no

change occurs in the output levels of three sensors, the DC controller will

compare the measurements taken as soon as PS5 turns ON against the slice

level to identify the size of the original.

2. If the copyboard cover is open, i.e., PS5 is OFF, the cassette containing paper

of the largest size will be selected of all the cassettes set in the copier.

3. Sizes of Originals

The DC controller identifies the size of originals based on specific combinations of

original detection signals (DSITE0 through 3) as follows:

a. AB Configuration

Table 3-401

1997 CANON INC. CANON NP6045 REV. 1 MAR. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)

CHAPTER 3 EXPOSURE SYSTEM

3-15

DS3

Sensor 3

DS2

Sensor 2

Sensor 1

Sensor 0

Size

None or

A5, A5R

B5R

A4R

DS1

Original detection signal