Paper Jam Detection - Canon LBP-1760 Service Manual

CHAPTER 2
C. Paper Jam Detection
The following paper sensors are installed to detect whether the paper is present or not and
whether the paper is fed normally or not.
• Reversed paper sensor (PS703)
• Duplexing unit pick-up sensor (PS701)
The microprocessor (CPU) determines whether paper is jammed or not by checking whether
paper is present or absent at the sensors at check timing stored in the memory.
If the CPU determines that a jam has occurred, it stops duplex feeding and notifies the jam
occurrence to the engine controller.
1. Pick-up delay jam
The CPU assesses a pick-up delay jam if the pre-feed sensor (PS102) does not detect the lead-
ing edge of the paper within the prescribed period of time (about 2 sec.) after the paper was
picked up, or if the top of page sensor (PS103) does not detect the leading edge of the paper with-
in the prescribed period of time after the start of duplex pick-up.
2. Reverse delay jam
The CPU assesses a reverse delay jam if the reversed paper sensor (PS703) does not detect the
leading edge of the paper within the prescribe time (about 2.2 sec.) after the fixing unit delivery
sensor 1 (PS501) detects the leading edge of the paper.
3. Reverse stationary jam
The CPU assesses a reverse stationary jam if the reversed paper sensor (PS703) does not detect
the trailing edge of the reversed paper within the prescribed period of time (about 4.2 sec.) after
detecting the leading edge.
4. Duplexing unit pick-up delay jam
The CPU assesses a duplex pick-up delay jam if the duplexing unit pick-up sensor (PS701) does
not detect the leading edge of the paper within the prescribed period of time (about 1.5 sec.) after
the reversing is completed.
5. Duplexing unit pick-up stationary jam
The CPU assesses a duplex pick-up stationary jam if the duplexing unit pick-up sensor (PS701)
does not detect the trailing edge of the paper within the prescribed period of time (about 4.3 sec.)
after the duplexing unit pick-up starts.
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