Operation; Toner Level Detection Control; Toner Supply Control To The Toner Hopper; Toner Supply Control To The Developing Unit - Konica Minolta bizhub 500 Service Manual

Theory of Operation Ver1.0 Feb.2006

12.3 Operation

12.3.1

Toner level detection control

A. Toner level detection control
Toner remaining in the toner hopper is detected by the toner remaining sensor (PZS). When toner remaining in
the hopper is found below the prescribed amount, a toner supply signal is issued to the printer control board
(PRCB). This signal is transmitted to the operation board (OB) through the overall control board (OACB). Accord-
ingly, OB displays a message in LCD on the LCD board (LCDB).
B. Detection timing
• At all times while in printing.
12.3.2

Toner supply control to the toner hopper

A. Operation
When the toner remaining sensor (PZS) detects the reduced level of remaining toner, the toner bottle motor
(M10) turns ON and rotates the toner bottle to supply toner in the toner bottle to the toner hopper.
When PZS detects the toner level being restored to its prescribed level, M10 turns OFF to get back to the stand-
by condition.
B. Toner bottle position detection
The toner supply section is provided with the toner bottle position sensor (PS28) to detect the rotational position
of the toner bottle whether it is at the home position.
12.3.3

Toner supply control to the developing unit

A. When the power switch (SW2) is turned ON
A specified period of time after SW2 turns ON, the TCR sensor (TCRS) detects the toner density in the develop-
ing unit. At this time, when a detected value is found below the initial density recorded in the CPU in the overall
control board (OACB), the toner supply motor (M4) and the toner solenoid (SD5) turn ON to supply toner from
the toner hopper to the developing unit.
B. While in printing
While in printing, the toner density is detected by the TCR sensor (TCRS). The ON time periods of the toner sup-
ply motor (M4) and the toner solenoid (SD5) are decided according to the output voltage of TCRS to supply
toner from the toner hopper to the developing unit.
TCRS output voltage
Less than 2.01 V
2.01 to 2.14 V
2.14 to 2.22 V
2.22 to 2.28 V
2.28 to 2.32 V
2.32 to 2.39 V
2.39 V or more
Toner supply time period
0 second
0.10 seconds
0.15 seconds
0.20 seconds
0.25 seconds
0.40 seconds
0.50 seconds
12. TONER SUPPLY SECTION
35