Canon STAPLER STACKER SS-72 Service Manual page 54

CHAPTER 2
H. Paper Jam Detection
The following sensors are installed on the stapler stacker in order to detect the presence of the
paper and whether the paper is being fed properly or not.
• Entrance paper sensor (PI1)
• Reversing paper sensor (PI2)
• Delivery paper sensor (PI3)
• Staple tray paper sensor (PI4)
Paper jams are judged by these sensors; whether they detect the paper or not at check timing
stored in the microcomputer (CPU) on the stapler stacker driver PCB. If CPU judges as paper
jams, the delivery operation of the stapler stacker is interrupted and the stapler stacker informs
the option controller PCB of the jams.
1. Entrance paper sensor delay jam
The CPU detects an entrance paper sensor delay jam if the leading edge of the paper does not
reach the entrance paper sensor (PI1) within the prescribed time after the CPU receives a load
notice command from the option controller.
2. Entrance paper sensor premature arrival jam
The CPU detects an entrance paper sensor premature arrival jam if any one of the following
events occurs when the leading edge of the paper reaches the entrance paper sensor (PI1) after
paper feeding begins.
• The tray is changed.
• The delivery paper sensor (PI3) detects the trailing edge of the preceding paper when the deliv-
ery method is changed (from face-down to face-up or from face-up to face-down).
• Stapling is performed.
• No prior notice comes from the option controller.
• There is no print paper feed data.
3. Reversing paper sensor delay jam
The CPU detects a reversing paper sensor delay jam if the leading edge of the paper does not
reach the reversing paper sensor (PI2) within the prescribed time after the leading edge of the
paper passes through the entrance paper sensor (PI1).
4. Delivery paper sensor delay jam
a. Face-down delivery
The CPU detects a delivery paper sensor delay jam if the leading edge of the paper does not reach
the delivery paper sensor (PI3) within the prescribed time after the leading edge of the paper
passes through the reversing paper sensor (PI2).
b. Face-up delivery
The CPU detects a delivery paper sensor delay jam if the leading edge of the paper does not reach
the delivery paper sensor (PI3) within the prescribed time after the leading edge of the paper
passes through the entrance paper sensor (PI1).
5. Delivery paper sensor stationary jam
a. Face-down delivery
The CPU detects a delivery paper sensor stationary jam if the trailing edge of the paper does not
pass through the delivery paper sensor (PI3) within the prescribed time after the delivery paper
sensor (PI3) detects the leading edge of the paper.
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