4Toner Supply Control; Toner Supply Control; 5Recovery Sequence; Recovery Sequence - Canon iR4570 Series Service Manual

7.8.4 Toner Supply Control

iR2270 / iR2870 / iR3570 / iR4570
Supply of Toner from the Toner Bottle to the Sub Hopper
If the "absence of toner inside the sub hopper" is detected while the main motor is rotating, the bottle motor is rotated
intermittently (on for 3 sec, off for 2 sec), and the length of time during which the absence is detected is checked
using a counter that increases its count for each on-off cycle. When the count reaches 20 (about 100 sec), the machine
will assume that the sub hopper has become empty, and will indicate the Add Toner message on its control panel.
The counter is reset when the presence of toner inside the sub hopper is detected during any on-off cycle.
If the "absence of toner inside the developing assembly" is detected while the main motor is rotating and the
developing clutch is on, the machine rotates the sub hopper feedscrew motor intermittently (on for 1 sec, off for 1
sec). The rotation is monitored by a counter that increases its count when the developing sensor state is off during a
single on-off cycle; when its reading reaches 20 (about 40 sec), the machine will assume that its developing assembly
is more or less empty (i.e., there is a possibility of the ongoing generating black prints if printing continues), and will
issue a No Toner error, suspending image formation operation. The counter is reset when the presence of toner is
detected inside the developing assembly.
E020-0000
If the absence of toner is detected by the developing assembly toner level sensor and the presence of toner is detected
by the hopper toner level sensor, the route of supply from the sub hopper to the developing assembly may be clogged
or the output of these toner sensors may be faulty.
This error code will be indicated when the soft counter reaches 194 (about 388 sec). The counter is designed to
increase its count when the hopper sensor level is on during a single on-off cycle while toner is being supplied from
the sub hopper to the developing assembly.

7.8.5 Recovery Sequence

iR2270 / iR2870 / iR3570 / iR4570
The machine is not equipped with a mechanism to detect the replacement of its toner cartridge, but is designed to
execute toner recovery sequence in response to the following, assuming that the cartridge has been replaced:
1. the front cover has been opened and closed after the machine has detected the absence of toner inside the toner
cartridge and the developing assembly.
2. the machine has been turned off and then on after it has detected the absence of toner inside the toner cartridge and
the developing assembly.
The machine's recovery sequence is as follows:
1. the machine rotates the toner cartridge motor. (intermittently by rotating it for 3 sec and stopping it for 2 sec)
2. if the toner level sensor inside the sub hopper detects the "presence of toner," the machine stops the recovery
sequence.
3. after repeating the foregoing intermittent operation 20 times and if the toner level sensor inside the sub hopper still
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