Canon i-SENSYS LBP5300 Series, Service Manual

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Chapter 2
2-20
F-2-27
2.4.4.3 ETB cleaning
0013-7513
/ i-SENSYS LBP5360 / i-SENSYS LBP5300
For the purpose of preventing stain on the back of paper, the ETB cleaning is required by returning the residual toner on the ETB to the photosensitive drum.
This control is performed by the DC controller under the following conditions.
- Power is turned ON
- Before and after operation of the color misregistration corrective control
- Before and after operation of the image stabilization control
- Door is closed
- After completion of printing on specified the universal size of paper
<Detailed cleaning operation>
There are negative and positive potential residual toner on the ETB during printing. Upon start of the ETB cleaning, the DC controller makes the drum voltage zero
[V] for magenta (M) and yellow (Y), but makes that negative [V] for cyan (C) and black (Bk). This transaction is done by each primary charging roller of four color
cartridges. On the other hand, the negative bias is applied to the M/Y transfer rollers and the positive bias to the C/Bk rollers. This brings a greater potential differ-
ence between the photosensitive drum and the ETB. In a reverse way of the image transfer process, both positive and negative charged residual toner on the ETB
are returned to the photosensitive drum at once; the negative potential residual toner is returned by the negative biases, and the positive potential
residual toner is returned by the positive biases.
a. Transfer roller voltage detection
b. Attraction roller voltage detection
ETB engaged roller
ETB
Attraction roller
Constant
current
V
Voltage
detection
Constant
current
Current
Transfer roller
(Black)
ETB
Photosensitive drum
(Black)
V
Voltage
detection