6) The two laser beams pass through the collimator lens and the cylindrical lens to strike the four-sided mirror, which is rotating at a constant speed.

7) The laser beam reflected by the four-sided mirror focuses on the photosensitive drum passing through the focus lens and the reflective mirror at the front of the

four-sided mirror.

8) When the four-sided mirror starts to rotate at prescribed speed, the laser beam on the photosensitive drum starts to scan the surface of the drum at its prescribed

speed.

9) When the photosensitive drum rotates and the laser beam scans on the drum at each prescribed speed, the latent image is formed on the photosensitive drum.

Twin beam method

The laser unit unifies with two laser diodes (LD1, LD2). In one scanning operation, the two diodes (LD1, LD2) emit light to write two lines simultaneously.

This enables a twofold printing with same printing speed.

1st scanning line

2nd scanning line

3rd scanning line

4th scanning line

Feed direction

2.3.1.2 Laser Control Circuit

LBP3370 / LBP3310

The laser control controls the laser driver to turn the two laser diodes (LD1, LD2) ON/OFF according to the LASER CONTROL signals sent from the engine con-

troller.

The circuit diagram of the laser control is illustrated below.

Image area

F-2-3

LD1 scanning line

LD2 scanning line

Chapter 2

0018-3094

2-3

Table of Contents