
Symbol Index
No. Description Note
M16 60 Side Fence Jogger
(Duplex machines only) Drives the side fence jogger to square the
paper stack.
Sensors
S1 27 By-pass Feed Paper
Width Informs the CPU what width paper is in the
by-pass feed table.
S2 31 By-pass Feed Paper
End Informs the CPU that there is no paper in the
by-pass tray.
S3 51 Upper Tray Paper End
(Non-duplex machines
only)
Informs the CPU when the upper paper tray
runs out of paper.
S4 107 Upper Relay Detects the leading edge of paperfrom the
upper tray to determine the stop timing of the
upper paper feed clutch, and detects misfeeds.
S5 29 Upper Tray Upper Limit
(A153/ machines only) Detects the height of the paper stack in the
upper paper tray to stop the upper tray lift
motor.
S6 52 Lower Tray Paper End Informs the CPU when the lower paper tray
runs out of paper.
S7 106
Lower Relay Detects the leading edge of paper from the
lower paper tray to determine the stop timing of
the lower paper feed clutch, and detects
misfeeds.
S8 30 Lower Tray Upper Limit
(A153/A156 machines
only)
Detects the height of the paper stack in the
lower paper tray to stop the lower tray lift motor.
S9 100 LCT Lower Limit
(LCT machines only) Sends a signal to the CPU to stop lowering the
LCT bottom plate.
S10 26 LCT Paper End
(LCT machines only) Informs the CPU when the LCT runs out of
paper.
S11 28 LCT Upper Limit
(LCT machines only) Sends a signal to the CPU to stop lifting the
LCT bottom plate.
S12 28 Registration Detects the leading edge of the copy paper to
determine the stop timing of the paper feed
clutch, and detects misfeeds.
S13 50 Image Density
(ID) Detects the density of various patterns on the
drum during process control.
S14 53 Toner Density
(TD) Detects the amount of toner inside the
development unit.
S15 39 Lens Horizontal HP Informs the CPU that the lens is at the
horizontal home position.
S16 20 Lens Vertical HP Informs the CPU that the lens is at the full-size
position.
S17 15 Scanner HP Informs the CPU when the 1st and 2nd
scanners are at the home position.
S18 24 3rd Scanner HP Informs the CPU when the 3rd scanner is at
the home position.
S19 21 Original Length-2 Detects the length of the original. This is one of
the APS (Auto Paper Select) sensors.
S20 45 Fusing Exit Detects misfeeds.
S21 16 Platen Cover Informs the CPU whether the platen cover is up
or down (related to APS/ARE functions).
ARE: Auto Reduce and Enlarge
S22 54 Toner End Instructs the CPU to add toner to the toner
supply unit, and detects toner end conditions.
FSM 2-9 FT5535/4527/4522