Canon iR3570 Series, Service Manual

Page: 246 / 722

Chapter 7
7-10
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
0007-5234
iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N / / iR4570N / iR2230 / / / iR3530 /
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 does not detect the "presence of toner," the
machine will assumes that the toner cartridge has not been replaced and cause the toner cartridge motor to stop.
7.8.6 Toner Level Detection
0006-6350
iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N / / iR4570N / iR2230 / / / iR3530 /
Detecting the Level of Toner Inside the Sub Hopper
The machine checks the level of the toner sensor located inside the sub hopper every 100 msec, and will assume the presence of toner inside the sub hopper if the
sensor goes on twice or more continuously (200 msec or more).
If the machine detects the absence of toner 100 times or more (10 sc or more) as the result of its check on the sensor level made every 100 msec, the machine will
assume that there is no toner inside the sub hopper.
The machine executes the foregoing detection at all times regardless of the state (on or off) of the main motor and the developing clutch.
Detecting the Level of Toner Inside the Developing Assembly
1. The machine samples the output of the toner level sensor located inside the developing assembly every 100 msec (only if the developing clutch is on).
2. The machine uses a period of 1.5 sec (15 times; cumulative sampling of periods when the clutch is on) as the unit of measurement: if the presence of toner is
detected 3 times or more, it will assume that there is toner inside the developing assembly; if the presence of toner is detected less than 3 times, on the other
hand, it will assume that there is no toner inside the developing assembly.
However, in the case of the iR3570/iR4570 Series machines, the drive of the main motor is controlled to 2 different speeds, and the toner inside the developing
assembly is driven by the main motor (using a clutch), requiring a switchover of methods of detection as follows:
Normal Speed Mode
The machine uses a period of 1.5 sec (25 times; cumulative sampling of periods when the clutch is on) as the unit of measurement: if the presence of toner is detected
3 times or more, it will assume that there is toner inside the developing assembly.
Low-Speed Mode
The machine uses a period of 2.5 sec (42 times; cumulative sampling of periods when the clutch is on) as the unit of measurement: if it detects the presence of toner
5 times or more, it will assume that there is toner inside the developing assembly.
The machine converts the number of samplings and the number of times toner detection has been executed when switching over methods of detection. (The con-
version is based on the speed-to-amount relationship.)
7.9 Transfer Unit
7.9.1 Outline of the Transfer Unit
7.9.1.1 Outline
0006-5997
iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N / / iR4570N / iR2230 / / / iR3530 /
The transfer unit [1] consists of the transfer roller and the static eliminator.
The transfer roller rotates in connection with the photosensitive drum.
Bias is applied to the static eliminator so that sheets can be separated from the drum.
F-7-19
7.9.2 Controlling the Transfer Bias
7.9.2.1 Transfer Roller Bias Control
0006-5998
iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N / / iR4570N / iR2230 / / / iR3530 /
The machine changes the output depending on the site environment (absolute moisture content), paper type, paper width, and source of paper.
Environment: 5 settings according to absolute moisture content
Paper type: plain paper, envelope, heavy paper, tracing paper, transparency, bond paper, label sheet
Paper width: size boundaries as defined by 2 points
Source of paper: if from cassette (including pedestal); if from multi-feeder, i.e., 1st side (half-speed), 2nd side (half-speed)
Transfer bias
Transfer bias: 1000 to 6000 V