Owing to the spatial relationship between the BD circuit and the laser diode, the machine is not capable of detecting the BD signal of each color individually. As

such, it uses the BD signal of Bk to serve as the reference BD signal when generating the BD signal for Y, M, and C.

The following is a timing chart depicting the relationship of the BD signals of individual colors and the video signals:

[1] Reference BD

6.2.1.3 Controlling Synchronization in Sub Scanning Direction

/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880

The machine executes synchronization in sub scanning direction so as to match the lead edge of an image and the lead edge of paper. This control is executed for

every color, and is controlled by the DC controller.

The following is the sequence of operation:

1) When the print command arrives, the DC controller generates the sub scanning sync signal (PTOP) with reference to its internal timer.

2) The DC controller generates the sub scanning sync signals (Y-TOP, M-TOP, C-TOP, Bk-TOP) of individual colors based on the PTOP signal, and sends them

to the main controller.

3) When these signals arrive, the main controller generates video signals (VDO Y, VDO M, VDO C, VDO Bk) a specific period of time thereafter, and sends them

to the DC controller. As a result, the laser drivers of individual colors go on to emit laser beams that scan the surface of the photosensitive drum starting at a

specific point.

M-CON

D-CON

[3]

[1]

VDO (C,Bk)

VDO (Y,M)

[2]

F-6-4

VDO

F-6-5

Chapter 6