The DC controller checks the result of these detection mechanisms when the power is turned on, when the front door is opened/closed, and for each print job. If it

finds that the level of waste toner is above a specific value, the DC controller issues to the main controller either of 2 messages (waste toner case full alert, waste

toner case full).

The following shows the relationship between messages and waste toner levels:

Message type

Waste toner full warning

Waste toner full

[1] Waste toner count

[2] Waste toner case full alert detection signal

[3] Waste toner case

[4] Waste toner

[5] Waste toner screw

UN6: waste toner sensor (optical sensor)

The following is a brief description of the foregoing types of detection:

1. detection by an optical sensor

The machine uses an optical sensor (UN8) mounted behind the waste toner case to check the amount of waste toner. The detection takes place when the level of

waste toner is between 0% and 95%, and the result is sent to the DC controller, which will issue a waste toner case full alert to the main controller when the result

indicates the level to be 95%.

MEMO:

The sensor consists of a light-emitting segment (LED) and a light-receiving segment (PD).

When the level of waste toner is low, the light from the LED is received by the photodiode. When the level increases, on the other hand, the presence of waste toner

blocks the light from the LED, thus preventing reception of light by the photodiode, thus causing the output of the sensor to change from High to Low. The change

in the sensor output causes the DC controller to assume that the waste toner case is 95% full with waste toner.

7-38

"Waste toner bottle needs to be replaced soon. (Continued printing possible.)"

"Replace waste toner bottle."

[2]

[5]

[3]

T-7-15

Message contents

M-CON

[1]

D-CON