Lexmark C 950 Service Manual

Diagnostic aids 3-49
  5058-030
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4.Use the metal tab to lift the staple guard, and then remove any jammed or loose staples.
5.Close the staple guard.
6.Press down on the staple guard until it clicks into place.
7.Push the staple cartridge holder firmly back into the stapler unit until the staple cartridge holder clicks into 
place.
8.Close the stapler door. 

3-50  Service Manual 5058-030  
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9.Close door G.
10.If necessary, touch Continue, jam cleared from the printer control panel. 

Diagnostic aids 3-51
  5058-030
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Security Reset Jumper
Each device contains a hardware jumper with which an administrator can:
•Erase all security templates, building blocks, and access controls that a user has defined (i.e. the factory 
default configuration); or
•Force the value of each function access control to “No Security” (all security templates and building blocks 
are preserved but not applied to any function).
Note:  If the “Enable Audit ” setting in the Security Audit Log...

3-52  Service Manual 5058-030  
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Printer theory of operations
Print engine theory
Four toner cartridges (cyan, yellow, magenta, and black) are used to create text and images on media. Each of 
the colors has a photoconductor drum and an image transfer unit (ITU). To obtain a print output, each drum will 
undergo the following processes: 
1.Charge
2.Exposure
3.Development
4.1st transfer
5.Cleaning (Drum/Charge roll)
6.2nd Transfer
7.Electric Discharge
8.Cleaning (Transfer belt/2nd...

Diagnostic aids 3-53
  5058-030
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Step1: Charge
Voltage is sent from the high-voltage power supply (HVPS) to the charge roll, which places a uniform negative 
electrostatic charge on the surface of the drum. The drum surface is made of a photoconductive material that 
holds an electrical charge as long as the drum is not exposed to light. Light striking the drum causes the surface 
charge to neutralize. 
The charge roll is a conductive roll that is positioned slightly above the...

3-54  Service Manual 5058-030  
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Service tips
•If the surface of the charge roller is damaged (for example, if it has a nick or a pit), it will cause 
the charge to be uneven on the photoconductor. This will cause a repeating mark on the 
printed page. Check the service manual for the repeating marks table.
•If the charge roller is severely damaged, the surface of the photoconductor will not be charged 
properly, and heavy amounts of toner will be deposited on the photoconductor....

Diagnostic aids 3-55
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Step 3: Development
The toner inside the cartridge is circulated using a toner bottle auger driven by the toner dispense motor. The 
toner particles then travel through the toner dispense auger and to the developer housing.  
Inside the developer unit, the augers circulate and distribute the toner particles into the magnet roll surface 
before they reach the photoconductor drum.
as
Toner dispense
motor
Toner bottle
auger
Toner dispense auger
Developer...

3-56  Service Manual 5058-030  
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The toner contained within the PC cartridge has a magnetic property that causes it to adhere to the magnet roll. 
The metering blade spreads the toner into a very thin layer on the magnet roll. Friction between the magnet roll 
and the blade generates a small electrical charge that is transferred to the toner.
The surface of the magnet roll is made up of a thin sheet of conductive material. The HVPS supplies the magnet 
roll with two voltages: a DC...

Diagnostic aids 3-57
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Step 4: 1st Transfer
When the latent images are developed on each photoconductor, the high-voltage power supply sends voltage to 
the 1st transfer rollers inside the transfer belt. The charge difference between the developed toner image on the 
photoconductor surface and the 1st transfer roller causes the images to transfer to the surface of the transfer 
belt for each color. This takes place by a direct surface-to-surface contact between the...

3-58  Service Manual 5058-030  
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Step 5: Cleaning (Drum/Charge roll)
The Cleaning Blade removes any toner that remains on the drum after the transfer process. The toner that the 
Cleaning Blade removes is collected inside the sealed PC Cartridge and reused. This is performed after each 
plane of color has been transferred to the transfer belt from the photoconductors.
An erase lamp also electrically cleans the drum. The drum is discharged by exposure of light from the erase 
lamp....