Canon IR2200, IR3300 Detecting the Size of Originals, Points of Detection, Outline of Detection

CHAPTER 2 ORIGINAL EXPOSURE SYSTEM

4 Detecting the Size of Originals

4.1 Outline

The machine automatically identifies the size of originals based on the combination of in- tensities measured by reflection type sensors and CCD at specific points.

•For main scanning direction, the CCD is used to take measurements (if AB, 4 points; if Inch, 2 points).

•For sub scanning direction, a reflection type photosensor is used (1 point).

4.2 Points of Detection

For main scanning direction, the No. 1 mirror base is moved to the following points in re- lation to the position of the original to measure the intensity at each point.

For sub scanning direction, on the other hand, measurements are taken while holding the sensor in place at a specific point.

AB-Configuration

Inch-Configuration

Point of original detection 1

Point of original detection 2

Point of original B5 detection 3 Point of original detection 4

Original sensor

B5R

A4R

B4

A4A3

		Original sensor
Point of original		LTRR	LGL
detection 1
Point of original		279.4×431.8mm
detection 2	LTR	(11"×17")

Point of CCD original detection

Point of CCD original detection

F02-402-01

4.3 Outline of Detection

The machine identifies the size of originals in the following two steps:

[1]Detecting External Light (main scanning direction only)

While keeping the scanning lamp off, the CCD level at each point of detection in main scanning direction is measured. A point at which external light is detected will be iden- tified as indicating the absence of an original, enabling the identification of the width of an original.

[2]Detecting the Sensor Output Level

The scanning lamp is turned on, and the CCD level at each point of detection in main scanning direction is measured. In addition, the reflection type photosensor in sub scanning direction is turned on to measure the sensor output.

The combination of these output measurements is used to identify the size of the origi- nal. For specific movements, see the pages that follow.

COPYRIGHT © 2001 CANON INC. CANON iR2200/iR2800/iR3300 REV.0 MAR. 2001 2-11 R