Scanner Cartridge; Scanner Cartridge Overview; Block Diagram - Canon BJC-55 Service Manual

Part 4: Technical Reference

6. SCANNER CARTRIDGE

6.1 Scanner Cartridge Overview

The scanner cartridge is a replaceable scanner unit that carries a one-line 128 pixel
BASIS. The scanner separates each of the three RGB primary colors of the LED by
scanning the same line three times. The color image is output by 8-bit signals, 256
gradation in each RGB primary color. For a monochrome image, the image is lit with a
green LED and scanned once to output either a 8-bit or 2-bit signal. The maximum
scanning resolution is 360 dpi × 360 dpi.
The light source LED within the scanner lights up and illuminates the document on the
platen. The light rays hit the image and using an imaging lens the reflected light rays
are converged onto the BASIS. The converged light rays are converted to analog signals
by the BASIS. After the analog signals have been converted to digital signals by the
scanner controller, the scanned image is processed and the image data is sent to the
computer via the printer's Centronics interface.

6.1.1 Block diagram

Light Emitting Section
Figure 4-32 Scanner Cartridge
Printer
Scanner Cartridge
Scanner Controller
Interface Control
Image Processing
+24V dc
+5V dc
A/D Converter (10 Bit)
Analog Signal Control
Sensor Control
BASIS (Image Sensor)
Figure 4-33 Block Diagram
4-46
Light Receving Section
Signal Contact
LED (R, G, B)
Scanning Documents
BJC-50