Lexmark C 950 Service Manual

							Diagnostic aids 3-89
  5058-030
Go Back Previous
Next
• Front tamper motor
–  A stepping motor that moves the front tamper for tamping.
–  Clockwise rotation of this motor moves the front tamper to the rear side. Counterclockwise rotation of this 
motor moves the tamper to the front side.
• Rear tamper motor
–  A stepping motor that moves the rear tamper for tamping.
–  Clockwise rotation of this motor moves the rear tamper to the front side. Counterclockwise rotation of this 
motor moves the tamper to the rear side.
Stapler
This section describes the operation of the stapler.
Stapling operation
Sheets of media fed from the punch are tamped on the compiler unit assembly, and then stapled at specified 
positions by the command of the printer.
Staple positions
There are four stapling modes:
• Front staple (corner) [front corner] 
The stapler staples a set of media obliquely (45 degrees) after the rear tamper 
aligns the media to the front side. 
Rear tamper
Front tamper
Sensor (front tamper HP)
Front tamper motor Sensor (compiler
media in) Rear tamper motor Sensor (rear
tamper HP)
Front Rear
Process direction 
						

							3-90  Service Manual 5058-030  
Go Back Previous
Next
• Rear staple (corner) [rear corner]
This type of stapling is applied for media with a width of 216 mm or more.
The stapler moves to the rear corner and staples a set of media obliquely (45 
degrees) after the front tamper aligns the media to the rear side.
• Rear Staple (Straight) [rear straight]
This type of stapling is applied for media with a width of less than 216 mm.
The Stapler staples a set of media in parallel with the media edge after the front 
tamper aligns the media to the rear side. 
• Dual Staple [dual]
The Stapler staples a set of media at fixed positions (front/rear sides) in parallel 
with the media edge after the front tamper aligns the media to the specified position 
for each media size. 
Media sizes that allow stapling
Media size that allows stapling depends on stapling positions.
The following table shows media sizes and the applicability of stapling for each staple position.
Front 
cornerRear 
cornerRear 
straightDual
A3 SEF Yes Yes No Yes
A4 LEF Yes Yes No Yes
11 x 17 in. SEF Yes Yes No Yes
8.5 x 11 in. LEF Yes Yes No Yes
8K SEF(GCO), 16K LEF(GCO) Yes Yes No Yes
B4 SEF, B5 LEF Yes Yes No Yes
8 x 10 in. LEF Yes Yes No Yes
8.5 x 14 in. SEF / 8.5 x 13 in. SEF / 
8.5 x 11 in. SEFYes No Yes Yes
A4 SEF Yes No Yes Yes
8 x 10 in. SEF Yes No Yes Yes
Yes: Applicable, No: Not applicable
Front Rear
Process direction
Front Rear
Process direction
Front Rear
Process direction 
						

							Diagnostic aids 3-91
  5058-030
Go Back Previous
Next
Stapling one sheet 
Upon receiving the stapling command from the printer with one sheet remaining on the compiler unit assembly, 
the finisher ejects the media to the stacker media bin without stapling it. 
Stapling multiple size media
When sheets with different sizes and the same width (example: A4L and A3S) are present on the compiler unit 
assembly, all the sheets are stapled and then ejected to the stacker media bin.
When sheets with different widths are present on the compiler unit assembly, stapling is stopped when a 
different width is detected. Such different-width sheets are forcibly ejected to the stacker media bin. 
Media limits for stapling
The number of sheets to be stapled is limited to prevent damage to the stapler. 
• If the number of sheets of one set to be stapled exceeds the limit of the compiler unit assembly, the 
exceeding sheets are not stacked on the compiler unit assembly, and are forcibly ejected to the stacker 
media bin without being stapled.
• After the forcible ejection of media, if the number of following sheets of one set to be stapled exceeds the 
limit of the compiler unit assembly, the exceeding sheets are also ejected forcibly to the stacker media bin 
without being stapled.
• After that, even if the number of following sheets of one set to be stapled falls within the limit, the sheets are 
also ejected forcibly to the stacker media bin without being stapled.
The upper limit (and default) of the compiler unit assembly media capacity when stapling is 50 (variable (10 to 
100) by the non-volatile memory).
Stapler operation
The stapler stays at the front home position, that is, at the front staple (corner) position when the power is 
turned on. 
The stapler starts stapling when a set of sheets to be stapled is stacked on the compiler unit assembly. 
The stapler does not move during stapling in the front staple mode. 
						

							3-92  Service Manual 5058-030  
Go Back Previous
Next
In any mode other than the front staple mode, the stapler moves to the specified position, and then performs 
stapling.
Stapler unit assembly
The stapling operation is executed by closing the stapler unit assembly.
The stapler unit assembly, containing the staple motor, the sensor (staple home), the sensor (self priming), and 
the sensor (low staple), is activated by the staple motor.
Forward (clockwise) rotation of the motor drives the stapler to staple a set of sheets, and returns the stapling unit 
to the home position. 
If stapling fails, the motor rotates reversely (counterclockwise) to return the stapler unit assembly to the home 
position. 
When staples become low, the low staple sensor detects it, and stapling stops automatically, displaying an 
alarm message. The message is also displayed when the staple cartridge is not installed. 
Stapler carriage motor asm
Sensor (stapler carriage HP)Media handling
direction
Sensor (staple home)
Sensor (self priming)
Stapler unit motor Sensor (low staple)Stapler unit assembly 
						

							Diagnostic aids 3-93
  5058-030
Go Back Previous
Next
Functions of stapler sensors/motors
• Sensor (stapler carriage HP)
–  A photo-interrupter sensor that detects the stapler home position, rear staple (corner) position, and rear 
staple (straight) position.
–  It turns high (+5 V dc) (light blocking) when the stapler comes to the specified position.
• Stapler carriage motor assembly
–  A stepping motor that moves the stapler unit assembly.
–  Clockwise rotation of this motor moves the stapler unit assembly to the rear side, while counterclockwise 
rotation moves the stapler unit assembly to the front side.
• Sensor (low staple) in the stapler unit assembly
–  A photo-interrupter sensor that detects when the stapler unit assembly is nearly out of staples.
–  It turns high (+5 V dc) when 20 staples are left.
• Sensor (self priming) in the stapler unit assembly
–  A photo-interrupter sensor that detects that staples are at the stapler unit assembly end; it also detects 
failure in stapling.
–  It turns low (0 V dc) (light blocking) when stapling is ready.
• Sensor (staple home) in the stapler unit assembly
–  A photo-interrupter sensor that detects the stapler unit assembly home position; it also detects failure in 
stapling.
–  This sensor also functions as a trigger to stop the staple motor.
–  It turns low (0 V dc) (light blocking) while the stapler unit assembly stays at the home position. 
• Stapler unit motor (in the stapler unit assembly)
–  A DC motor to activate the stapler unit assembly for stapling.
–  Clockwise rotation of this motor enables stapling, while counterclockwise rotation returns the stapler unit 
assembly.
Booklet Operation
The booklet media entrance roll assembly driven by the booklet media entrance drive motor will deliver media 
from the finisher entrance and stack it against the booklet end guide in the booklet unit. When the booklet end 
guide is at the bottom of the booklet unit it will continue to accept media. Once the proper amount of media is 
reached, stapling will occur and booklets will be delivered in sets to the booklet media bin.
The booklet media exit roll assembly is driven by booklet folding/exit drive motor assembly and delivers booklets 
to the booklet media bin. During printing, paper drawn to the booklet compiler is aligned by the booklet paddle 
shaft assembly which is driven by booklet paddle shaft drive Motor.
When a sheet of paper enters the booklet compiler, tamping operation is performed by two moving tampers 
moving towards the front and rear. The front tamper is driven by front booklet tamper drive motor; rear booklet 
tamper drive motor. Tamping operation will be performed a final time after the last sheet is received. 
Sensor (stapler carriage HP)Stapler carriage motor asm
Stapler
rack gear 
						

							3-94  Service Manual 5058-030  
Go Back Previous
Next
Documents in the compiler tray are assembled towards the front. For center stapling and folding positions, one 
set of document is assembled and moved to the center. 
The booklet end guide is lifted to where the fold will divide the paper into two equal halves. When the printouts 
are stapled, the booklet end guide will be raised so that the stapled position is at the folding position. The 
stapling position is slightly lower than the folding position center line.
When the movement from the booklet folding/exit drive motor is transferred to the knife through the engagement 
of the sector gear, the knife will thrust forward and then return to the original position after one full rotation. At the 
folding position, the knife is thrust forward to fold the paper between booklet folding roll and booklet folding nip 
roll.
Paper is folded into two halves by the booklet folding roll driven by the booklet folding/exit drive motor and is 
delivered to the booklet media bin by the booklet media exit roll assembly. The booklet media bin belt will move 
at a fixed interval for every set of booklets that are created.
Functions of booklet sensors and motors
• Sensor (booklet media entrance)
–  This photo sensor detects the media delivery to the booklet unit.
• Sensor (booklet media exit)
–  This photo sensor detects paper delivery to booklet media bin.
• Booklet media entrance drive motor assembly
–  This stepping motor drives the booklet media entrance roll assembly.
• Booklet folding/exit drive motor assembly
–  This DC motor drives booklet folding roll, booklet media exit roll assembly, and knife. 
						

							Diagnostic aids 3-95
  5058-030
Go Back Previous
Next
• Booklet knife solenoid
–   This solenoid transfers the booklet folding/exit drive motor assembly to the knife through the gear.
• Sensor (booklet front tamper HP)
–  This photo sensor detects the home position of the booklet front tamper.
• Sensor (booklet rear tamper HP)
–  This photo sensor detects the home position of the booklet Rear tamper.
• Sensor (booklet compile media in)
–  This photo sensor detects paper present in the booklet compiler tray.
–  Booklet front tamper motor
–  This stepping motor drives the booklet front tamper.
• Booklet rear tamper motor
–  This stepping motor drives the booklet rear tamper.
• Sensor (booklet knife HP)
–  This photo sensor detects the home position (stored condition) of knife.
• Sensor (knife folding)
–  This photo sensor detects the fold position (protruded condition) of knife.
• Booklet staple assembly
–  This booklet stapler consist of two stapler units (including stapler low switch) and booklet stapler head 
motor.
• Booklet paddle motor
–  This DC motor drives the paddle at the booklet section.
• Sensor (booklet end guide HP)
–  This photo sensor detects the home position of the booklet end guide.
• Booklet end guide drive motor
–  This stepping motor moves the booklet end guide up and down.
Sensor (booklet
media entrance)
Booklet media entrance
drive motor
Booklet folding/exit
motor assembly
Booklet knife solenoid Sensor (booklet media
exit roll assembly)
Booklet media
exit roll assembly
Booklet folding
roll assemblyBooklet media
entrance roll
assembly 
						

							3-96  Service Manual 5058-030  
Go Back Previous
Next
• Sensor (booklet drawer interlock)
–  This photo sensor detects when the booklet unit is set.
• Sensor (booklet bin media present)
–  This photo sensor detects paper availability on the booklet media bin. If 15 sets of printouts are detected 
in the booklet media bin, it will be considered as Full Stack.
Booklet media bin 
Operation
The upper media bin contains the sensor (upper media bin full) to detect the media stack volume in the upper 
media bin.
Once the sensor detects a full stack (500 sheets) in the upper media bin, ejection of media to the upper media 
bin is inhibited until a full stack is reset. 
Functions of upper media bin sensors
• Sensor (upper media exit)
–  A photo-interrupter sensor that detects that media has come to the upper media exit roll assembly top at 
the exit of the upper media bin.
–  When media reaches the upper media exit roll assembly top, the actuator leaves the sensing area, which 
turns the sensor to high (+5 V dc). 
• Sensor (upper media bin full)
–  A photo-reflective sensor that detects the media stack volume in the upper media bin.
–  It turns high (+5 V dc) when it detects a full stack.
Stacker media bin
The stacker media bin goes up and down to an appropriate position according to the volume of media fed from 
the compiler unit assembly so as to properly stack media to a full stack. 
Booklet bin drive motor
Sensor (booklet bin
media present) 
						

							Diagnostic aids 3-97
  5058-030
Go Back Previous
Next
Operation
The stacker media bin moves to an appropriate position according to the volume of media fed from the compiler 
unit assembly. The sensor (stacker bin level 1) and the sensor (stacker bin level 2) detect the height of media in 
the stacker media bin, and the sensor (stacker bin level encoder) determines the volume of media in the tray.
When media or the stacker media bin comes between the light emitter and the photo-receiver of the sensor 
(stacker bin level 1) and sensor (stacker bin level 2), the emitted light is blocked, and the sensors turn high. The 
height of media or the stacker media bin is detected based on the levels of these sensors. 
This sensor information is used to control the elevator motor. The motor is activated to move the stacker media 
bin while the sensor (stacker bin level) turns from the light blocking state to the light receiving state.
The sensor (stacker bin no media) is turned On or Off by the actuator attached to the carriage assembly right on 
the rear side of the finisher. In case the stacker media bin abnormally goes up above the sensor (stacker bin no 
media), the sensor (stacker bin upper limit) is installed above the sensor (stacker bin no media) for protection 
against abnormal operation.
If an operator removes media from the stacker media bin during printing, it is detected by the sensor (stacker bin 
level 2), and the ejection of media to the stacker media bin is inhibited. Then the elevator motor is activated to 
move the stacker media bin to the sensor (stacker bin level 1) sensing area. Thus, the ejection of media to the 
stacker media bin is restored.
If an operator removes media from the stacker media bin while printing is stopped, it is detected by the sensor 
(stacker bin level 2). After three seconds have passed, the elevator motor is activated to move the stacker media 
bin to the sensor (stacker bin level 1) sensing area. Thus, the ejection of media to the stacker media bin is 
restored.
Sensor (stacker bin level)
Bin: height
moves
downwardBin: properBin: low
moves upward 
						

							3-98  Service Manual 5058-030  
Go Back Previous
Next
The stacker media bin lowers according to the volume of media it contains. If any obstacle under the tray 
hinders the tray from lowering, the stacker lower safety warning is detected, and the stacker media bin is 
stopped. 
Full stack detection
A full stack is detected when media in the stacker media bin becomes full to prevent media jam or falling of 
media to the floor. The stacker media bin can stack up to approximately 3000 sheets.
The media volume in the stacker media bin is detected at every 10% (approximately 300 sheets) and notified to 
the Controller. 
Furthermore, the stacker media bin can stack up to 200 sets (default) of stapled media. 
The stacker media bin can continue to stack media until media volume reaches either of the limits above. 
In the mix stacking mode, all the sizes are allowed until a media volume of approximately 300 sheets in the 
stacker media bin is detected. 
The mix stacking mode indicates one of the following cases:
• A larger (any size of media) sheet of media is stacked on a smaller sheet.
For example: A4LEF (297x210) media is stacked on A4SEF (210x297) media. 
Note:  When B5LEF (257x182) media is stacked on A4LEF (297x210) media, this is not mix stacking.
ActuatorStacker bin
lift motor assemblySensor (stacker bin
level encoder)Sensor (media
eject shaft HP) Media eject
motor assembly Sensor (media
eject clamp HP) Eject clamp motor
Sensor (stacker bin level 1)
Stacker media bin
Sensor (stacker bin level 2)
Sensor (stacker bin
upper limit)
Sensor (stacker bin no media)