Paper Jam Detection - Canon CLBR 460ps Service Manual

E. Paper Jam Detection
The following paper sensors are provided to detect whether paper is present and whether the
paper is fed normally:
• Registration paper sensor (PS2)
• Delivery paper sensor (PS7)
The microcomputer (M-CPU) determines if paper jam has occurred by checking for the presence
of paper in the sensor at the timing stored in the CPU.
If the M-CPU determines that a jam has occurred, it will stop the print operation and report
the jam to the video controller.
1. Pick-up delay jam
After the multi-purpose tray or cassette paper pick-up operation, if the leading edge of the paper
does not reach the registration paper sensor (PS2) within a specified period of time from the
detection of the ITB HOME POSITION DETECTION signal (/ITBHP) closest to the start of sec-
ondary transfer, the M-CPU assesses a pick-up delay jam.
Note: In case of full-color printing from the multi-purpose tray, the M-CPU performs the pick-
up retry operation (see page 2-81 for pick-up retry function) before assessing a pick-up
delay jam.
2. Pick-up stationary jam (illegal paper length jam)
The M-CPU determines a pick-up stationary jam (illegal paper length jam) if the trailing edge of
paper has not passed the registration paper sensor (PS2) within a specified period of time after
detection of the ITB HOME POSITION DETECTION signal (/ITBHP) closest to the start of sec-
ondary transfer.
3. Delivery delay jam
The M-CPU determines a delivery delay jam if the paper has not reached the delivery paper sen-
sor (PS7) within a specified period of time after detection of the ITB HOME POSITION DETEC-
TION signal (/ITBHP) closest to the start of secondary transfer.
4. Delivery stationary jam
The M-CPU determines a delivery stationary jam if the paper has not passed the delivery paper
sensor (PS7) within a specified period of time after detection of the ITB HOME POSITION DETEC-
TION signal (/ITBHP) closest to the start of secondary transfer.
5. Residual paper jam
a. After the power is turned ON, if the registration paper sensor (PS2) detects paper before the
fixing roller temperature reaches 100°C, the M-CPU assesses a residual paper jam and stops
the printer immediately. If the sensor detects paper after the fixing roller temperature has
reached 100°C and the pick-up motor (M2) has started running, the paper is automatically
delivered.
b. After the power is turned ON, if the delivery paper sensor (PS7) detects paper, the M-CPU
assesses a residual paper jam and stops the printer immediately regardless of the fixing
roller temperature.
CHAPTER 2
2 - 89