Lexmark C 950 Service Manual
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Diagnostic aids 3-49 5058-030 Go Back Previous Next 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 Go Back Previous Next 9.Close door G. 10.If necessary, touch Continue, jam cleared from the printer control panel.
Diagnostic aids 3-51 5058-030 Go Back Previous Next 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 section of the “Security Menu ” is activated, the device logs a message each time that the jumper is used. A small lock icon identifies the jumper’s position on the RIP card. Also, to make it easier to separate the small yellow plastic jumper from the 3-pin connector, a looped handle is attached to the top of the small yellow jumper that covers the 3-pin connector. An administrator controls how a jumper reset affects a device by configuring the jumper-related setting on the Security Web page. Note: Administrators can discourage tampering with the jumper by securing the entire RIP card cage (of which the jumper is a part) with a Kensington lock. or, to completely negate the effects of a jumper reset, an administrator can select the “No Effect ” value for the jumper-related setting on the Security Web page or in the “Security Reset Jumper ” setting in the “ Security Menu”. To perform a jumper reset operation: 1.Power the device off. 2.Remove the Kensington lock from the card cage (if installed). 3.Remove the small yellow jumper that covers a pair of the jumper’s pins. 4.Replace the small yellow jumper so that it covers the pins adjacent to its original position. 5.Replace and secure the Kensington lock on the card cage (if installed). 6.Power the device on. Note: The movement of the small yellow jumper from position A to position B triggers the reset, not the specific positions. When the device is powered on, it labels the current position of the small yellow jumper (let’s say position A) as the “home ” position. If, at the next POR, the device detects that the small yellow jumper has moved from its previous “home ” position (position A) to the “ other ” position (position B), then it performs a jumper reset. After performing the reset, the device also relabels the “ other ” position (position B) as the “ home ” position (now position A is the “other ” location). Note: The admins security settings are lost when the RIP card is replaced. Secure settings are those that are configured under the Settings->Security->Edit Security Setups menu. These are all the PINs, Passwords, and other Building Blocks and Security Templates that define the devices protection of functions and menus. In other words, if the customer is using LDAP to authenticate users to use the Copy function, then after the RIP card is replaced, the device will no longer have that LDAP configuration or the Copy function protected.
3-52 Service Manual 5058-030 Go Back Previous Next 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 transfer roll) 9.Fusing Printing process flow In summary, the printer’s controller board receives print data and the command to print. The controller board then initiates the print process. The controller board is the command center for the EP process and coordinates the various motors and signals. The high-voltage power supply sends a charge to various components in the EP process. The printhead LED arrays fire on the photoconductors and alter the surface charge relative to the planed image for each photoconductor. Each photoconductor rotates past its respective developer roll, and toner is developed on the surface of each photoconductor. The four separate color images are then transferred to the transfer belt as it passes under the photoconductors. After the image is transferred to the transfer belt, the photoconductors are cleaned and recharged. The transfer belt carries the four-colored image towards the transfer roll. Media is picked up from the tray and carried to the transfer roll where the image is then transferred from the transfer belt to the media. The timing of the paper pick is determined by the speed of the transfer belt. The media is carried to the fuser belt and roller where heat and pressure are applied to the page to permanently bond the toner to the page. The fuser rollers push the media into the output bin. The transfer unit is cleaned and the process begins again for the next page. DRUM (Y) chargeexposure Cleaning (Drum/Charge roll)development 1st transfer DRUM (M) chargeexposure Cleaning (Drum/Charge roll)development 1st transfer chargeexposure Cleaning (Drum/Charge roll)development 1st transfer chargeexposure Cleaning (Drum/Charge roll)development 1st transfer Cleaning (Transfer belt/2nd transfer roll 2nd transfer Electric discharge Fusing Belt Paper DRUM C DRUM (K)
Diagnostic aids 3-53 5058-030 Go Back Previous Next 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 surface of the drum. The HVPS supplies the charge roll with two voltages: a negative DC charge voltage and an AC discharge voltage that is used for electrically cleaning the drum. HVPS (-VDC) (-VDC) Ground Conductive Tube Photoconductive Surface 0V-VDC value DRUM Drum Surface Voltage Drum Surface Image Ground Charge roll HVPS (-VDC) (-VDC) Ground Conductive Tube Photoconductive Surface 0V-VDC value DRUM Drum Surface Voltage Drum Surface Image Ground Charge roll
3-54 Service Manual 5058-030 Go Back Previous Next 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. This will cause the printed page to be saturated with 100% of each color. The imaging basket will need to be replaced sooner. Step 2: Exposure The printhead LED generates a scan line of LED light. Image data received from the RIP card assembly modulates this scan line, turning it on and off according to image information that is received from the host computer and software. Through the use of a series of rotating and stationary mirrors within the printhead, the scan lines are applied on the negatively charged drum surface. Whenever the print controller sends a command to print a black pixel, the printhead LED switches on long enough to shine onto the drum at a single pixel point. That point is now discharged and slightly less negative than the surrounding negative charge. The less negative areas are considered positive. This discharge/no discharge process creates an invisible, electrostatic image on the surface of the drum. This image is called a latent image. LED Light 0V DRUM Drum Surface ImageDrum Surface Voltage Laser Beam Discharge Level Invisible Latent Image Laser Beam Printhead
Diagnostic aids 3-55 5058-030 Go Back Previous Next 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 housing Toner cartridge Augers Magnet roll
3-56 Service Manual 5058-030 Go Back Previous Next 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 voltage and an AC voltage. The DC voltage is used to transfer toner from the magnet roll to the surface of the drum. The AC voltage agitates the toner on the magnet roll, making toner transfer easier. The magnet roll maintains a negative DC electrical potential. Negatively charged areas of the drum have a lower electrical potential, or a higher relative negative value than the magnet roll. Discharged areas of the drum have a higher electrical potential, or a lower relative negative value, than the magnet roll. A discharged point on the surface of the drum now appears less negative in relation to the negative charge on the magnet roll. The toner adhering to the magnet roll is always in contact with the drum surface. When a less negative point on the drum (a discharged area) comes in contact with the more negative charged toner on the magnet roll, toner transfers from the magnet roll to that point on the drum. The toner will attract only to the area of the photoconductor drum that was exposed to the printhead LED scan line. This process would be similar to using glue to write on a can and then rolling it over glitter. The glitter sticks to the glue but won’t stick to the rest of the can. There is now a visible toner image on the drum surface. The image is called a developed image. Service tips •Never touch the surface of the developer roller with your bare hand. The oil from your skin may cause a charge differential on the surface, and toner will not stick properly. The result would be repeating blotches of voids/light print on a page. To solve this, the affected cartridge must be replaced. •If the developer roller is damaged, it will not contact the surface of the photoconductor properly. The result could be repeating marks, thin vertical voids, or thin vertical lines of color on the printed page. Check the surface of the developer for damage. Magnetic RollMetering Blade TonerHVPS DRUM -VDC Drum Surface Voltage Drum Surface Image Toner at -VDC Developer Bias value Discharge Level 0VVisible Developed Image
Diagnostic aids 3-57 5058-030 Go Back Previous Next 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 photoconductors and the transfer belt. Service tips •Never touch the surface of the transfer belt with your bare hand. The oil from your skin will cause a charge differential on the surface, and toner will not stick properly. The result would be repeating blotches of voids/light print on a page. To solve this, the transfer belt must be replaced. •Don’t use solvents or other cleaners to clean the transfer belt surface. No matter how careful you are, the surface will be compromised, causing scratches or a charge differential that will produce a void or light blotch on the printed page. To solve this, the transfer belt must be replaced. HVPS Transfer belt 1st transfer roll (Cyan) Photo conductor drum(Cyan)
3-58 Service Manual 5058-030 Go Back Previous Next 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. Step 6: 2nd Transfer As the paper travels and makes contact with the transfer belt, the 2nd transfer roll assembly is charged with negative DC voltage from the HVPS. This causes the toner image to transfer from the transfer belt to the surface Cleaning BladeUsed Toner Charge roll DRUM -VDC DRUM Ground Erase lamp LED array