Specifications

12-3. Control for Each Erase Function

All LA3 LEDs are turned ON approx. 250 msec. after PC Drum Drive Motor

M5 has been energized (see p. M-26) and the leading edge erase and edge

erase controls are thereafter provided.

The LA3 LEDs are turned OFF approx. 1,050 msec. after Scanner Control

Processor Board PWB-J has output an SCEND signal, which completes a

series of erase controls.

= Leading Edge Erase =

•

The image along the leading edge of the electrostatic latent image on the

surface of the PC Drum is erased by turning ON all LA3 LEDs. This

prevents a black streak which would otherwise be produced by the shadow

of the Original Width Scale. It also helps the leading edge of the paper to

be easily separated from the Fusing Rollers.

•

All LA3 LEDs are kept ON for a given period of time after PWB-J has

output an Image Leading Edge signal (BASE). The leading edge erase is

then switched to edge erase. The leading edge erase time varies

depending on the zoom ratio, mode (File Margin, Edge/Frame Erase), and

whether "Leading Edge Erase" of the Tech. Rep. Choice is set to "Yes" or

"No." See the Table below.

"Yes" (4 mm) "No"

Normal

File Margin

Normal

File Margin

10 15 20 10 15 20

Erase Width (mm) 4 14 19 24 0 10 15 20

Timer (msec.) 75 105 120 135 60 90 105 120

In an enlargement mode, the above erase widths are made greater

according to the particular zoom ratio as follows.

Zoom Ratio 1.001 to 1.500 1.501 up

Erase Width Correction (mm) + 1. 7 + 3. 4

Timer Correction (msec.) + 5 + 10

M-64