Canon LBP-3000 Service Manual Download

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Chapter 2

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The machine checks for a jam with reference to the presence/absence of paper at a specific sensor at such times as programmed in advance.

When the CPU detects a jam, it will suspend the ongoing printing operation and communicate the fact to the video controller.

2.5.2.2 Delay Jams

2.5.2.2.1 Pickup Delay Jam

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The machine uses a retry mechanism in which it executes pickup operation twice for detection of a pickup delay jam caused by a pickup fault.

The CPU executes pickup operation twice if the paper leading edge sensor (PS801) does not detect the leading edge of print paper within about 1.4 sec

after the pickup solenoid (SL1) goes on.

Thereafter, if the paper leading edge sensor (PS801) does not detect the leading edge of print paper within about 1.4 sec, the machine will assume the

condition to indicate a pickup delay jam.

2.5.2.2.2 Delivery Delay Jam

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The CPU will assume the presence of a delivery delay jam if the delivery sensor (PS803) does not detect the leading edge of print paper about 1.8 sec after

the paper leading edge sensor (PS801) has detected the leading edge of print paper.

2.5.2.3 Stationary Jams

2.5.2.3.1 Pickup Stationary Jam

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The CPU will detect the presence of a pickup stationary jam if the trailing edge of print paper is not detected about 4.6 sec after the paper leading edge

sensor (PS801) has detected the leading edge of print paper.

Moreover, it will also assume the presence of a pickup stationary jam if the paper width sensor (PS802) does not detect the trailing edge of paper within

200 msec after the paper width sensor (PS802) has detected the leading edge of paper and the paper leading edge sensor (PS801) has detected the trailing

edge of paper.

2.5.2.3.2 Delivery Stationary Jam

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The CPU will assume the presence of a delivery stationary jam if the delivery sensor (PS803) does snot detect the leading edge of print paper during a

period of about 2.0 sec after the paper leading edge sensor (PS801) has detected the trailing edge of print paper.

2.5.2.4 Other Jams

2.5.2.4.1 Wrapping Jam Around the Fixing Assembly

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The CPU will assume that paper has wrapped around the fixing assembly if the delivery sensor (PS803) does no detect the trailing edge of paper within

about 1.3 sec after the delivery sensor (PS803) has detected the leading edge of print paper and then about 1.3 sec after the paper leading edge sensor

(PS801) has detected the leading edge of print paper.

2.5.2.4.2 Residual Jam at Start-Up

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The CPU will identify a residual jam when the paper leading edge sensor (PS801) or the delivery sensor (PS803) detects print paper at the start of initial

rotation.

2.5.2.4.3 Door Open Jam

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The CPU will identify a door open jam if the leading edge sensor (PS801) or the delivery sensor (PS803) detects print paper when the door is identified as

being open.

2.5.3 Multi-purpose Pickup

2.5.3.1 Pickup from the Pickup Tray/Manual Feed Tray

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When paper is picked up from either the pickup tray or the manual feed tray, the machine makes sure that no more than a single sheet of power is picked