To enable highly detailed reproduction of images, the machine switches the resolution in main scanning direction and sub scanning direction from 600 to 1200 dpi.

At such times, the laser output (intensity) is reduced by 1/2 for main scanning direction, while the speed is reduced by 1/2 for sub scanning direction.

[1] 1 pixel

6.2.1.2 Controlling Synchronization in Main Scanning Direction

Color iR C3380G / Color iR C2880G / Color iR C3380i / Color iR C3380 / Color iR C2880i / Color iR C2880 / iR C3480 / iR C3480i / iR C3080 / iR C3080i / iR

C2550

The machine controls synchronization in main scanning direction to ensure the write start position of individual lines in main scanning direction.

Synchronization occurs for each line of each color, and is controlled by the DC controller.

The following is the sequence of operation:

1) The DC controller sets the Bk laser control signal to APC mode (LC_CTLP4(0)=0, LC_CTLP4(1)=1), thus forcing the laser diode of the Bk driver circuit to go

on.

2) The laser beam path is equipped with a BD circuit used to receive the beam.

3) The BD circuit detects the laser beam, generates the reference BD signal (BD RAW1), and sends the result to the DC controller.

4) In response, the DC controller sends these reference BD signals to the main controller in the form of the main scanning sync signals (BD Y, BD M, BD C,

BD Bk).

5) When these signals arrive, the main controller sends video signals (VDO Y, VDO M, VDO C, VDO Bk) to the DC controller a specific period of time there-

after; as a result, the respective laser drivers go on to emit laser beams that will scan the surface of the photosensitive drum starting at a specific point of individual

lines. (See Notes.)

6-4

[1]

600DPI

1/2

Drum

1200DPI

1/2

Laser Driver

F-6-3

0013-8533

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