Service manual

Chapter 2
2-33
F-2-48
2.4.3 Detection Jams
2.4.3.1 Jam Detection Outline
2.4.3.1.1 Outline
0007-4990
To detect the presence of paper and whether paper has been correctly fed, the following paper sensors are provided:
- Registration sensor (PS711)
- Fixing delivery paper sensor (PS1)
- Fixing front paper sensor (PS720)
- paper feed sensor (PS717)
The CPU in the DCNT Board determines whether a paper jam has occurred by checking for the presence of paper at the sensor unit at the timing stored in the CPU.
If the CPU determines a jam, it stops a print operation and notifies the jam occurrence to the SCNT Board.
Occurrence timings for each jam are listed below. A specified period is timed at a normal speed (1/1-speed).
2.4.3.2 Delay Jams
2.4.3.2.1 Pickup Delay Jam
0007-4991
If the leading edge of paper does not reach the registration sensor (PS711) within a specific period of time (T) after the start of pickup (i.e., the clutch or the solenoid
at the inlet slot goes on), the CPU will identify the condition as being a pickup delay jam.
T = about 1.1 sec (multifeeder tray) or about 1.7 sec (250-sheet feeder)
2.4.3.2.2 Delivery Delay Jam
0007-4992
When the leading edge of paper does not reach the fixing delivery paper sensor (PS1) within a specified period (t) after the start of a re-pick-up operation (the
registration clutch is on), the CPU determines a delivery delay jam.
t = Approx. 2.3 seconds.
2.4.3.3 Stationary Jams
2.4.3.3.1 Pick-up Stationary Jam
0007-4993
When the trailing edge of paper does not pass the registration sensor (PS711) within a specified period (t) after the start of a re-pick-up operation (the registration
clutch is on), the CPU determines a pick-up stationary jam.
t = Approx. 3.4 seconds.
2.4.3.3.2 Delivery Stationary Jam
0007-4994
When the leading edge of paper does not pass the fixing delivery paper sensor (PS1) within a specified period (t) after it has passed the registration sensor (PS711),
the CPU determines a delivery stationary jam.
t = Approx. 2.4 seconds.
2.4.3.4 Other Jams
2.4.3.4.1 Fixing Unit Wrapping Jam
0007-4995
CPU detects fixing unit wrapping jam, when there are any print papers inside the fixing front paper sensor when turning on the power or after closing the upper
cover.
2.4.3.4.2 Door Open Jam
0007-4996
When the top cover is opened during a print operation, the main CPU determines a door open jam.
2.4.3.4.3 Residual Paper Jam
0007-4997
The CPU determines a residual paper jam under the following conditions:
- Power is turned on.
- Returned from the sleep status.
- Door is closed after a jam occurrence.
- Registration sensor (PS711) and fixing delivery sensor (PS1) detect paper.
0
TH3 temperature
Td=50
30
60
Tu=45
Print time (minutes)
TH3 temperature