Canon imagePRESS 1135 Series Service Manual page 174

2
Technology > Pickup / Feed System > Pre-fixing feed Area > Fixing loop control
■ Fixing loop control
Since the thermal expansion of the fixing roller causes instability of the rotation period, even
if the rotation speed is constant, but the paper delivery speed of each the fixing roller and the
secondary transfer roller are different. Hence, sometimes the papers between the fixing roller
and the secondary transfer roller are too slacked, or too tense. Whether the paper slack (loop)
is too big or small, it will give bad effect to the image.
In order to always deliver the paper to the fixing unit in a perfect condition, this control
monitors the slack condition of the paper (loop), and switch the delivery speed accordingly.
And for the paper with feed direction less than 227.3 mm, it is not delivered at the same time
by the fixing roller and the secondary transfer roller, hence there is no loop control.
1. Fixing roller increases the speed.
Timing: before paper leading edge reaches the fixing roller
Standard sensor: loop detection sensor (PS147)
2. The paper is pulled after arriving in the fixing roller.
Increase speed
OFF
PS147
Loop
detection
sensor
2 Technology > Pickup / Feed System > Pre-fixing feed Area > Fixing loop control
PS19
Secondary
post-transfer
sensor
F-2-176
3. Loop detection sensor (PS147) is turned ON, and the fixing roller drops the speed.
Decrease speed
ON
PS147
Loop
detection
sensor
4. The paper slacks, and suctioned to the fixing feed belt.
5. Loop detection sensor (PS147) is turned OFF, and the fixing roller increases the speed.
Step 3 to 5 are repeated several times.
6. Loop control is finished, and the fixing roller returns to its stable speed.
Timing: after paper trailing edge passes the secondary transfer roller(in the specified time
after passing the PS59, the paper will be positioned in the post-secondary transfer sensor
(PS19)).
Standard sensor: post-registration sensor (PS59)
2-126
PS19
Secondary
post-transfer
sensor
F-2-177
2-126