Gestetner A265, Service Manual

Page: 102 / 855

DEVELOPMENT
A265/A267 2-50 SM
2.6.7 TONER SUPPLY IN ABNORMAL SENSOR CONDITIONS
ID sensor
Readings are abnormal if any of the following conditions occur:
•
Vsg
≤
2.5V
•
Vsg < 3.5V when maximum power (254) is applied
•
Vsp
≥
2.5V
•
(Vsg – Vsp) < 1.0V
•
ID sensor power required to make the standard output reaches the maximum
value (254)
The above ID sensor values can be checked using SP2-221.
When this is detected, the machine changes the value of Vref to 2.5V then does
the toner density control process (in a similar way to sensor control mode 2).
No SC code is generated if the ID sensor is defective.
TD Sensor
The TD sensor is checked every copy. If the readings from TD sensor become
abnormal, the machine changes the toner density control mode to fixed supply
mode 2, and the toner supply amount per page is always 200 ms, regardless of the
value of SP2-925. Then at the end of a job (if the optional fax unit is installed), or
100 copies after the TD sensor error was detected (if no fax unit is installed), an SC
code is generated (SC390) and the machine must be repaired. The 100-copy
threshold can be adjusted with SP 2-992.
2.6.8 TONER NEAR END/END DETECTION AND RECOVERY
The toner near end and end conditions are detected using the Vt and Vref values,
in a similar way to toner density control.
This is done in all toner supply modes except for fixed mode 2, when toner end is
not detected.
Toner Near End Detection
If Vt is at level 6 (see the table on the previous page) five times consecutively, the
machine enters the toner near end condition and the toner end indicator starts
blinking. Then the machine supplies toner for a certain time, which depends on the
setting of SP 2-923 (see the previous page).
CÓPIA NÃO CONTROLADA
CÓPIA NÃO CONTROLADA