Operation; Toner Remaining Detection Control; Toner Supply Control - Konica Minolta BIZHUB 750 Service Manual

12. TONER SUPPLY SECTION

12.3 Operation

12.3.1

Toner remaining detection control

A. Toner remaining detection control
The toner remaining in the toner hopper is detected by the toner remaining sensor (PZS). When the toner
remaining in the toner hopper gets below the specified amount, a toner supply signal is output to the printer
control board (PRCB). This signal is sent to the operation board /1 (OB1) through the image processing board
(IPB) and the system control board (SCB). As a result, OB1 displays a message on LCD on the LCD board
(LCDB).
B. Detection timing
• When the power switch (SW2) is ON.
• When the front doors /Lt and /Rt are opened and closed.
• When the drum motor (M2) starts to rotate.
• When the toner supply door is opened and closed.
12.3.2

Toner supply control

A. Purpose
When it is determined that the toner supply is required as a result of the toner density control, toner is supplied.
For the toner density control, see "24. IMAGE STABILIZATION CONTROL."
B. Operation
When the toner supply is required as a result of the toner density control, the toner supply motor (M12) turns ON
to supply toner from the toner hopper to the developing unit.
C. Timing
Toner is supplied when the trailing edge of paper in printing is detected. And the toner supply time varies
depending on the result of the toner density control and the paper size. This is normally controlled between 0 to
1.49 sec. The table shown below shows the relationship between the paper size and the toner supply time.
Paper size
A3
B4
8 x 13
A4
B5
B5R
A5
11 x 17
8.5 x 14
8.5 x 11
5.5 x 8.5
36
Toner supply time (sec.)
1.42
1.24
1.14
0.71
0.60
0.89
0.50
1.49
1.21
0.71
0.46
Theory of Operation Ver1.0 Aug.2005