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HP Confidential CLJ4500 & 4550 Print Quality Defects GuideCurtis Gold & Deborah Hahn November 2001

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Resolving Print Quality Defects

Consumables account for most print quality issues. Do not replace any hardware parts until you have ensured a consumable is not the source of the

print quality issue.

It is important to understand the EP process before embarking on PQ troubleshooting. A brief recap on the CLJ4500/4550 EP process is:1. The Primary Charge roller inside the imaging drum charges the OPC drum to approximately -600v.

2. The laser beam selectively discharges the OPC drum.3. Blackis developed onto the OPC drum first, then immediately transferred to the ITB.4. Magenta, Cyan, and Yellow are then developed (in that order), using the same process as black.

5. Once all 4 color planes have been transferred to the ITB, the image on the ITB is transferred to the paper via the secondary transfer roller.

Note on Lines / Banding / Streaking PQ issues:

It is important when addressing these issues to understand the paper verses banding orientations correct. Figure 1: Horizontal and vertical banding (The arrows for both pictures in Figure 1 indicate the process direction (or paper movement).

1- Horizontal banding (perpendicular to the process direction)

2- Vertical banding (parallel to the process direction)

Repetitive Defect Distances

Consumable Roller Distance

Image Drum Charge Roller 40mm (1.6 inches)OPC Drum 152mm (6 inches)

Toner Cartridges Black 37mm (1.5 inches)

Color 30mm (1.2 inches)

Fuser 131mm (5.2 inches)

ITB ICL Roller 40mm (1.6 inches)

Transfer Roller 53mm (2.1 inches)

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References to additional information

Several PQ issues mentioned in this guide are documented with greater detail in the Knowledge

Retrieval System (KRS).

To receive a login and password for KRS, contact ICO Technical Marketing at the following URL:

http://techweb.boi.hp.com/

Note: Several PQ defects are caused by 3rd-party / remanufactured cartridges. Refer to BPL10795

for complete information on identifying 3rd-Party cartridges.

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Blank Pages

DescriptionAll printouts, including printer test pages, exit the printer blank

Possible Causes Blocked laser shutter

The imaging drum is not rotating

The imaging drum shutter is not retracting

Defective ITB (if blank pages print continuously withoutstopping).

Defective drum drive assembly

Troubleshooting and Suggestions Disconnect the printer from the network before troubleshooting.

Check the tab on the imaging drum (See BPL90006, Figure 1 for

the location). Verify that it is present.

Check to see if white gear on the drum drawer is present (See

BPL90006, Figure 2 for the location).

Check service note C4084A-11 for troubleshooting a possibledefective ITB.

Recommended Parts ITB

White gear

HVPS

Imaging Drum

Carousel drive assembly

Drum Drive assembly

IMPORTANT NOTE: This issue is covered in a work

instruction. See document BPL90006. See service noteC4084A-11 for the defective ITB issue.

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Toner Dusting/Leaking

Description

Spots and small blobs of one of more than one toner color

appear on the printed page. Spots may also appear on theback side of print jobs.

Possible CausesToner dusting occurs when toner particles migrate from the toner

cartridges and deposit on the flaps that cover the toner cartridges. The

CMY cartridges use a non-magnetic toner that relies on static charging

to hold the particles in place. Many times, customers have cartridgesthat extend beyond the stated 6,000-page life. As a result, some of the

toner particles become "worn" and lose their ability to hold a charge.These particles can then fly away from the toner cartridge as toner dust

and deposit on the flaps.

Sometimes toner dust will build up on the toner cartridge itself, then

fall onto the transfer roller. As media passes over the transfer roller,

this toner is picked up and appears as spots that repeat and fade downthe page. The printer performs a cleaning cycle that removes toner

from the transfer roller, but it may not clean the roller entirely.

Troubleshooting and suggestions

Clean the transfer roller with a lint-free cloth

Clean out the waste toner collection tray

Check for 3rd party cartridges. (See BPL10795).

Replace the leaking cartridge(s)

Recommended PartsToner cartridge(s)

Toner cloths

Transfer roller(optional)

IMPORTANT NOTE: This PQ defect is covered in a work

instruction. See BPL90013.

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Toner Flaking

Description

Toner has flaked off the printed page and may be re-deposited

on other parts of the page. (The example shown here was aletter-sized label).

Possible Causes

The media is not within specifications. (Media is

heavier than then what is supported by the printer.

Toner may build up on the fuser and redeposit on the

next page.Troubleshooting and Suggestions

Verify that the media is within specifications

Recommended Parts

Fuser(optional) if it has been damaged by repeated use of

unsupported media.

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Smeared Print

Description

The printed image is smeared and may appear faded or diluted.

Possible Causes

Jammed media in or around the ITB, imaging drum, transfer roller, or fuser. (See

Figure 1).

The frame above the ITB cleaning roller has been bent, causing the cleaning roller

to push against the ITB belt every couple of inches. (See Figure 2).

Troubleshooting and Suggestions

Check the ITB for abrasion marks.

Check the ITB ICL roller for damage or for jammed media like an adhesive label.

Check for jammed media underneath the ITB's top cover.

Check for a damaged ITB (bent ITB frame).

Recommended parts

ITB

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Full-page Ghosting

Description

Entire images from the previous page "ghost" on the current page. In

this example, the Configuration page is ghosting on the EIO 1Configuration page.

Possible Causes

A defective ITB may cause the issue (most common).

3rd-Party Cartridges

The three high-voltage contacts on the middle front drawer

may be damaged or missing contacts (springs).

The cleaning roller cam clutch (CL3) is not engaging.

A failing High-Voltage Power Supply (HVPS) may cause this

issue due to improper charging of the ITB cleaning roller.

Site power. (Plug the printer directly into the wall).


Check the media.

Check the humidity and temperature.

Check the electrical connections in the middle front drawer.

Check the face plate and the cam shaft for CL3.

Recommended Parts

See BPL90043 for recommended parts.


instruction. See document BPL90043.

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Same page ghosting in a 40mm band(Process Direction)

Description

Ghosted images at a 40mm interval print down the page in theprocess direction. Color or black may ghost.

Possible Causes

The ITB ICL roller cam assembly may not reset normally,

causing the alignment marks not to align correctly.

Troubleshooting and Suggestions Measure the ghosted images with a PQ defects ruler.

Check for a label wrapped around the ICL roller.

Check the position of the alignment marks on the CL3

cam shaft. (The alignment marks should face out).

Recommended Parts Transfer kit

CL3



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Black Developer Ghosting (37mm)(Process Direction)

Description

Images repeat (ghost) down the page in 37mm increments,which matches the circumference of the developer sleeve on

the black toner cartridge.

Possible Causes

When printing a heavy black or solid dark color, the negative

charge that has been applied to the imaging drum cannot be

cleared quickly enough to eliminate the heavy toner buildup.The heavier the contrast between the solid image and the

background, the stronger the ghost image will appear and the

more often it will repeat.


Avoid using heavy concentrations of color against a

lighter, contrasting background

Move the solid image so a shaded area is not below it

Change the density of the shaded area

Recommended Parts

None

IMPORTANT NOTE: This issue is covered in KRSII. See

BPL11041 for complete details.

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Magenta or Black-Only Ghosting

Description

This defect appears as a streak of color down the page aftermagenta is laid down. It is best seen after printing three or

more consecutive font lists.

Possible Causes

The ITB cleaning roller is not applying enough positive

charge on the residual toner to carry the toner to the imaging

drum surface for cleaning. Refer to Service Note C4084A-12for complete details.


Print 20-100 consecutive color pages. (If the ghosting does not

disappear, replace the ITB).

Check the lot code on the ITB. A counter measure ITB is now

available. The lot code for the new ITBs are EGBXXXXXXX

or later.

Recommended Parts

ITB


instruction. See document BPL90043. Also see Service Note

C4084A-12.

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Same Page Positive Ghosting

Description

This issue appears as a dark shadow (ghost) in areas of lightgray on light half-tone colored backgrounds. The ghost image

repeats itself every 152 mm (6 inches).

Possible Causes

When the imaging drum is near the end of its life cycle, the

customer may start to see positive ghosting.


Changing the background color or tone in the application can

help resolve this issue.

Recommended PartsImaging drum



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Same Page Negative Ghosting

Description

This issue appears when dark images from one part of a pageare repeated as light ghosting in areas of medium gray or

medium halftone colored backgrounds. The ghost image

repeats itself every 152 mm (6 inches).

Possible Causes

After a new imaging drum is installed, the customer may seenegative ghosting. As the drum life progresses, the ghost image

may go away.


Change the background color or tone.

Recommended PartsNone



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CMYK Spots (6mm apart)(Process Direction)

Description

Rows of Cyan, Magenta, Yellow, and Black (CMYK) dotsprint down the page in the process direction. The distance

between the dots is 6mm. The dots may also appear to be gray

or black. In one version, the distance between the dot of a

given color and the next of the same color is observably

152mm or about 6 inches from one dot to the next dot of the

same color.

Possible Causes

A nick or scratch has been made on the imaging drum


Replace the imaging drum. (This will be the customer's

responsibility unless the drum is new).

Recommended parts

Imaging drum

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White Gapping

Description

This issue appears as a white line or gap, one or two pixels in width,

that surrounds filled areas of text. (Note the white gapping underneaththe eagle's wings).

Possible Causes

There is no hardware fix for this issue

Using halftone colors

Variations in line widths

Polarization within the chemical composition of the toners


Use the PCL driver

Change or alter the colors exhibiting white gapping

Avoid using halftone colors

Remove black borders or frames around a solid fill color

Adjust the registration numbers. (See Chapter 7 in the service

manual).

Recommended PartsNone

IMPORTANT NOTE: This issue is thoroughly explained in KRSII.

See document BPL10780.

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Yellow haze around red and green text

Description

Red and green text or thin lines may appear with a yellowhaze (a.k.a. yellow

halo) around the edges. This is a NO FIX issue. Some level of haloing mayalways exist.

Possible CausesHaloing is caused by yellow toner scatter and is more likely to manifest when anew yellow cartridge is installed and/or the other cartridges are weak or low.Yellow is the last color laid down. As a result, the area for yellow imaging is not

as sharp or focused electrically as the other colors. Haloing is increased by lowhumidity and unsupported media.


Check for unsupported media or low humidity

Try a color of text with less yellow

Check replacement history of the cartridges. One cartridge may be low.

Adjust the color density settings. (Reduce yellow).

Recommended Parts

None

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Gray hue shift

Description

Light, gray images may take on a color cast. Instead of a neutral tone (callout 1), the

gray image may appear slightly pink, blue, green, etc. (callout 2).

Possible Causes

The CLJ4550 & 4550 print a process gray (combination of cyan, magenta,

yellow and black). Unlike some printers, gray cannot be created using black

halftones.

Toner cartridges have lessened charging abilities over time.

The newest toner cartridge may create a hue of that color.


Clean the density sensor.

Increase or reduce the printer's density settings.

Change the color itself to a darker or lighter halftone to reduce hue shift.

Print a configuration page and look for any "weak" colors. Select gray scale in the driver if printing black only.

Recommended Parts

None. (Replacing the cartridges will temporarily fix the issue, however, gray hue shift

may reappear when one cartridge is later replaced).

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Color Halo or Haze around Solid Fill Areas or

Sharkskinning

DescriptionIn this example, a colored halo surrounds the 75% and 100%

boxes on the left-hand side of the configuration page. However,

this PQ issue can be seen anywhere on the page. ( This PQ

defect is usually more apparent in areas of higher toner

consentration).

Possible Causes

Low temperature and humidity.

Media with high resistivity. (The surface resisitivity of

the media changes once the first page is printed, so

duplexed pages are more susceptible).

Duplexing


Do not duplex the print job.

Try a media type with a lower surface resistivity.

Increase the humidity in the environment.

Recommended Parts

None

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Discharge marks or chicken scratch

DescriptionAn irregular, wave-like pattern of light lines appear in light,

neutral areas, typically on duplex print jobs. The effect is not

visible in darker sections of the image or text.

Possible Causes

The media (i.e. glossy paper) has low resistivity.

The environment's humidity and temperature are not within

the printer's specific range.

The secondary transfer roller is not seated correctly. Duplexed printing.


Change the paper type or print using an unopened ream.

Reseat the secondary transfer roller.

Avoid duplexing.

Increase the humidity in the printer's environment. Replace the ITB to reduce the amount of discharge marks,

although the media resisitivity and moisture content are the

main causes.

Send the print job at a slower speed (heavy or glossy

mode).

Recommended Parts

ITB (optional)


instruction. This defect shows up in many different ways. See

document BPL90041 for complete information.

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Black Toner Scatter

DescriptionIf you observe black color on a color page, you may observe a

scattering of toner particles around each black character.

These black characters may appear "fuzzy" around the edges

when compared to a monochrome LJ printout.

Possible Causes

Media with high surface resistivity (electricalcharacteristics).

Duplexed print jobs.

Color print jobs, not on black and white only pages.

Dry environmental conditions

If the "scattering" shows only on the bottom of

characters, the media has a high moisture content.


Use paper with a surface resistivity of: .0 to 15.0 X

10(10) Ohms/Sq 2.

Manually duplex print jobs verses using the automatic

duplex feature.

Recommended Parts

None

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Left to Right Faded Print (all colors)(Scan Direction)

Description

The entire image on a print out fades from left to right (as shown) or from right to left.

Possible Causes

Stiff media

A paper jam under the ITB assembly has popped the secondary transfer assembly up.

Broken ITB lifting arm cam.

Missing black cap on the plate kit.

Missing "c" bushing on one rail of the ITB drawer. The laser scanner mirror is blocked or contaminated. (It sits behind the silver grill).


Check media. Stiffer media can exhibit this issue.

Verify that the secondary transfer roller assembly is pushed down into place.

Reinstall the transfer roller.

Check the ITB lifting cams.

Check the black caps on the ITB lifting arms.

Check the "c" bushings on the ITB drawer (one is white, the other is black).

Clean the laser scanner grill behind the imaging drum

Recommended Parts

ITB cam assembly

Plate kit

ITB drawer

Laser/scanner(optional)

IMPORTANT NOTE: This issue is covered in a work instruction. See document

BPL900180.

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Fading Black Plane

Description

The black plane fades on print jobs. In this example, the black

is fading from left to right. This PQ defect generally occurs onolder printers with a fairly high page count.

Possible Causes

Issues with the black toner cartridge

Spring is bent over in the toner cartridge slot in the

carousel.

Media. (Stiffer paper can exhibit this problem). Mature printers with a fairly high page count.

The connections for CL2 and CL3 have been switched

on the Paper Feed PCB.

Defective carousel drive assembly. (The retractable HV

pin on this assembly has been found to wear, giving a

poor connection to the carousel).Troubleshooting and Suggestions

Replace the black toner cartridge

Try 80gm2

(20 lb) paper.

Recommended Parts

Black toner cartridge

Carousel drive assembly (optional) Carousel assembly (optional)



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Light Print on One Side

Description

Light print in all colors show on one side of a print job.

Possible Causes

The black cap on the ITB lifting cam lever is

missing.

The ITB lifting cam lever is damaged.

One of the "c" bushings on the middle front drawer is

missing.


Replace the black cap

Recommended Parts

Plate Cover (if the cap is missing)

Plate Kit (if the lever is damaged) Middle front drawer(optional)

Light Print

on Left hand side of page

caused by missing black plasticcap on ITB lifting cam lever.

Replace black cap if ITB lift

cam lever(s) damaged.

Bl k C l Pl O l

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Black Color Plane Only

Description

Black is the only color put down on a color print job like on this

configuration page.

Possible Causes

Grayscale is selected in the driver (This would not apply

to an internal print job like a configuration page).

CL2 is not functioning

Troubleshooting and Suggestions Check the grayscale setting in the driver.

Verify that CL2 is seated correctly.

Verify black only on an internal print job.

Check the first three calibration value sets on the

configuration page (See callout 1).

Recommended Parts

CL2

Paper Feed PCB

High Voltage Power Supply (optional)



R d C l Pl ( ) Mi i

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Random Color Plane(s) Missing

Description

Certain color plane(s) may intermittently disappear from print jobs. The first example shows a

CLJ4500 demo page missing the Magenta and Cyan color planes, while the second demo page

is missing the Magenta and Black color planes.

Possible Causes

The High Voltage contact on the Carousel assembly is broken/defective.


Verify that the color planes are missing from internal print jobs like a demo or engine test page.

Recommended Parts

High Voltage Power Supply (HVPS)

PS10

Carousel drive assembly (optional)

Carousel assembly (optional)

Missing Black Plane

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Missing Black Plane

Description

The black color plane is completely missing on a print job.

Possible Causes

The black toner cartridge is empty.

The sealing tape has not been removed from the

cartridge.

The connections for CL2 and CL3 have been switched

on the Paper Feed PCB.

The Carousel Assembly is defective.


Check the black toner cartridge for sealing tape.

Replace the black toner cartridge.

Check the CL2 & CL3 connections if the defect

appears after a service call.

Recommended Parts

Black toner cartridge

PS10

Carousel assembly

Cyan and Yellow Color Planes Missing

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Cyan and Yellow Color Planes Missing

Description

All printouts are missing the cyan and yellow color planes.

Possible Causes

A paper jam in the fusing area bent the thermister, causing the

fuser to overheat without an error reporting on the control

panel. The overheated fuser damaged the cyan and yellow

cartridges because they sit over the fuser in-between print jobs,

causing permanent damage.

This issue may also arise if the printer is unplugged before the

fans shut off.


Check the following parts to see if they are partially melted:

Rear door Feeder assembly

Rowel swing assembly

Carousel flap

All 4 toner cartridges

Fuser

Recommended Parts

Fuser

Black vertical streaks

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Black, vertical streaks(Process Direction)

Description

Black, vertical streaks are printed from the top edge of a

vertical page to the bottom edge.

Possible Causes

The cleaning blade on the drum may have been

gouged or scratched the drum surface.

An excessive buildup of toner on the drum.


Perform a half-self test to determine the origin of the

defect.

Check the imaging drum for a corresponding defect.

Recommended Parts

Imaging Drum

Black or Gray Vertical Lines

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Black or Gray Vertical Lines(Process Direction)

Description

A dark line or lines run down the printed page in the

process direction. These lines may be gray or darker

versions of the local colors in the printed images, and the

bands may be varying width on either side of the page.

Possible Causes

An excessive buildup of waste toner in one area of the

imaging drum.

Defect n the transfer roller or ITB.


Print a half-self test to locate the source of the issue.

Remove and inspect the drum, transfer belt, and the

transfer roller for similar bands. Gently rock the imaging drum back and forth to

distribute the waste toner.

Recommended parts

Imaging drum

ITB Transfer roller

One thin vertical line

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One thin vertical line(Process Direction)

Description

A light vertical line shows up on a vertical page. The line

fades out in the darker areas and may be hairline thin or as

wide as .625 centimeters (.0625 inches) long

Possible Causes

An obstruction such as a piece of lint may be protruding out

of the laser scanner window toward the front of the printer

obstructing the laser beam.


Clean the laser scanner windows with the printer's blue

cleaning brush. Do not use canned air.

Recommended Parts

Laser/Scanner Assembly



Fuser Inlet Guide Streaks

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Fuser Inlet Guide Streaks(Process Direction)

Description

One or more vertical lines may show on print jobs. (See

callout 1).

Possible Causes

Toner build-up on the fuser inlet guides

Duplexing print jobs

Troubleshooting and Suggestions Remove the fuser and inspect the fuser inlet guides.

(This may be difficult since the buildup may be the

same color as the guide).

Check for heavy duplex use.

Check for 3rd party cartridges (See document

BPL10795).

Recommended Parts

Fuser

White, vertical lines

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,(Process Direction)

Gouged ITB

Description

Vertical white lines run the entire length of a vertical page. The

lines appear even in width with possible rough edges.

Possible Causes

Damaged or obstructed ITB


Print a configuration page to verify the PQ defect

Check the ITB, transfer roller, and imaging drum. Remove any

obstructions.

Recommended Parts

ITB

Several, thin vertical lines

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,(Process Direction)

Description

Very fine, vertical lines less than a millimeter apart may

appear in various places on a vertical page. Ghost images

may appear to the left of the text and graphics. A fine, rope-

like pattern may appear to the right of colored graphics.

Possible Causes

Defective Formatter


Perform a half-self test

Print a configuration page if the defect appears on the

half-self test

Reseat the formatter if the defect appears on the engine

test

Recommended Parts

Formatter PCA

IMPORTANT NOTE: This PQ defect is covered in a

work instruction. See document BPL90112

Fine vertical lines

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(Process Direction)

Description

Light vertical lines an eighth of an inch apart cover the

printed images on a page. In some cases, patterns of dark

vertical lines cover the entire page.

Possible Causes

Incorrectly seated or defective formatter

Troubleshooting and suggestions Try a half-self test

Remove the formatter and any 3rd

party memory.

Reseat the formatter

Recommended Parts

Formatter PCA

IMPORTANT NOTE:

This PQ defect is covered in a work instruction. See

document BPL90014.

DC Controller Bands

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(Process Direction)

Description

The vertical page is broken into alternating 1/2 inch vertical sections. In the top and bottom thirds

of the page, the sections alternate displaced slices of the image; in the middle third of the page,

every other section is lighter than the original image.

Possible Cause

Defective DC Controller

Troubleshooting and Suggestions Reseat the firmware, memory, and formatter.

Remove third-party memory DIMM or EIO devices.

Dispatch technician to replace DC Controller if the issue cannot be resolved by performing

the preceding steps.

Recommended Parts

DC Controller

IMPORTANT NOTE: This PQ defect is covered in a work instruction. See document

BPL90112.

Horizontal Banding

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(Scan Direction)

Description

Horizontal banding shows through all colors. The bands

appear in an even pattern through the entire printable area.

Possible Causes

Defective High Voltage Power Supply

Troubleshooting

Print a configuration or demo page and verify that the bandingappears in all colors.

Recommended Parts

HVPS



Magenta & Cyan Banding

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Description

A horizontal magenta line followed by a cyan line prints out

on a vertical page at 152mm (6 inches) intervals, the distance

of the imaging drum.

Possible Causes

New drums can show this defect due to the charge roller

and/or the cleaning blade rubbing on the drum during

shipping. This defect is caused by a temporary positive chargethat gets trapped on the OPC surface.


Wait one to two days while running several copies. The defect

should clear up on its own. If it doesn't, replace the imaging

drum.

Recommended Parts

Imaging drum (optional)

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Gray, Horizontal Bands(Scan Direction)

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(Scan Direction)

Description

Gray, horizontal bands appear on all printouts.

Possible Causes

Defective Formatter PCA.


Verify that internal printouts like an engine test andconfiguration page show the horizontal bands.

Recommended Parts

Formatter PCA



Complete Discoloration from Edge to Edge

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Description

The entire page is discolored and streaked from edge to edge

with multiple colors.

Possible Causes

Defective High Voltage Power Supply


Verify that the defect shows up on an internal print job like aconfiguration page.

Recommended Parts

High Voltage Power Supply (HVPS)

Color Plane Offset

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Description

Colorplaneoffset will manifest itself when one colorplane

shifts up or down. In this example, the yellow colorplanehas shifted up higher than the other color planes.

Possible Causes

In many cases, the drum drive assembly is defective and

needs to be replaced.


Verify that the defect shows on a configuration page.

A service technician can perform additional diagnostic tests

like registration adjustments to isolate the cause.

Recommended Parts

Drum drive assembly DC controller



Solid Black Pages

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Description

All print jobs print as a solid black page without margins. This

defect also appears as a heavy grayish print out.

Possible Causes

The HVPS is normally attributed to this problem. If the

primary charge roller in the imaging drum does not charge the

drum to 600v, the charge levels could be close to zero. If this

occurs, toner will be attracted to these areas, causing a heavyblack or gray background.


Verify that the print out does not have a margin.

Check and clean the HVPS contacts that supply the

primary charge bias to the imaging drum (See Figure 3

in BPL90009 for the location).

Recommended Parts

Imaging drum

HVPS

DC Controller PCB



Solid Black Page with Margins

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Description

All print jobs print as a solid black page with margins.

Possible Causes

This defect shows the normal margin expected if an image

was printed, meaning the laser beam was switched on at all

times.

Troubleshooting and SuggestionsVerify that the solid black page has a margin

Recommended Parts

Laser/scanner assembly

DC Controller PCB

IMPORTANT NOTE: This issue is covered in a workinstruction. See document BPL90009.

Darker than normal print

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Description

Images, including printer test pages, print much darker than

normal.

Possible Causes

This is normally caused by the printer failing to go through

calibration. The configuration page displays four separate

blocks of numbers that indicate the calibration density

settings for each color. If these settings are all zeros, the

printer has not gone through calibration correctly. In some

cases, the density sensor (PS14) is covered by toner dust or

is defective.


Powercycle the printer and verify that the printer

calibrates.

Print a configuration page and check the calibrationvalues (See Figure 1 in BPL90143 for the location of the

calibration values).

Clean the density sensor.

Verify that the media is within specification

Remove any third-party memory.

Recommended Parts

Density Sensor (PS14)



Light/Mottled Print

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Description

Greens, blues, and purples -- colors that include CYM -- may have

thick horizontal bands of light running through them. A cyan

smudge appears at the top of the vertical page.

Possible Causes

Toner ages with carousel rotation and may become "old" before it

is used. Also, 3rd party cartridges can cause this issue (See

BPL10795).

Troubleshooting and Suggestions Check the age of the toner cartridges (in pages, if possible).

Observe the secondary colors on the configuration page for

mottling.

Use the following technique to determine which primary color

makes up the secondary color to identify which toner cartridge is

causing light or mottled print. To determine the low cartridge, lookfor the common colors showing the defect. For example, if green

and blue share the defect, then the common color is cyan.

1. Red = Magenta + Yellow

2. Green = Cyan + Yellow

3. Blue = Cyan + Magenta

Recommended Parts

Toner Cartridge

IMPORTANT NOTE: This issue is covered in KRSII. See

BPL08701 for complete details.

Light Bands of Color on OHTs (4550 only)

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Description

When using overhead transparencies (OHT), areas of the page

that are supposed to be solid color, print with bands of lighter

color mixed within. This issue is most often seen with blueand green colors and in MS PowerPoint files because they

often have a dark blue background. In this example, the

circled blue box should be solid dark blue. However, light

bands run through it. Banding is also seen in other areas of

this example, including the green background.

Possible Causes

The CLJ4550 uses different color tables for paper media than

for OHTs. This issue is caused by a problem with the OHT

color table.


Print the same file on paper media to see if the bandingreoccurs. If not, the problem is with the OHT color

table.

Upgrade to the latest firmware. (This issue was fixed

with firmware version 1.011.0 for the 4550).

Try using a different shade of color. If possible, do not

use blues and greens.

Recommended Parts

Firmware version 1.011.0 or newer

IMPORTANT NOTE: This issue is discussed in a service

note. See service note C7085-02.

Bubble Print

D i i

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Description

Bubble print can be described as overlapping circles randomly

spread throughout any print job.

Possible Causes

This defect usually occurs after service has been done on the

printer and is caused by arching at the connection to the imaging

drum. Possible causes may include the following:

Obstructed or defective drum ground connector

Defective imaging drum


Verify if the printer has been serviced. If so, try to determine

what parts were removed and/or replaced. Also, check the

HVPS contact on the drum.

Recommended Parts Drum ground connector

Imaging drum (optional)

Light random lines or missing toner

D i ti

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Description

Irregular light streaks or missing toner (scratch marks)

appear on images. Toner is raised (not smooth) across the

page and may not adhere well.

Possible Causes

Fuser roller delamination can be caused by the fuser

overheating, unsupported media melting to the fuser roller,

or fuser jams.


Verify that the media is within specifications.

Examine the fuser rollers. Instead of a smooth brown

surface, the rollers will likely show creases or missing

bits of the outer layer.

Recommended PartsFuser

Water Spots (Sand Dunes)

Description

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Description

Spots that look like water drops appear on a printout. These spots

appear more readily on the first (front) page of a duplexed page

and range from 1 to 7mm in diameter.

Possible Causes

Most likely, the cause rests with post transfer breakdown. The

issue is usually media related and is magnified on duplex print

jobs.


Check media specifications.

Try a fresh ream of paper.

Turn the duplex option off from the control panel.

Do not duplex.

Ensure that the resistor holder and transfer assembly are

making good contact.

Recommended Parts

Transfer Assembly

Colors switched or wrong

Description

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Description

The image prints with correct sharpness but with the

wrong colors. Depending on the color scheme of the

original image, the print may also appear too dark.

Possible Causes

This case was resolved by switching two of the toner

cartridges that had been installed in each other's slots in

the carousel. The cartridges had been forced into the

printer hard enough to break the locator keys off the

cartridge shutters.


Print a configuration page and check the bottom of

the page for a mismatch between two of the colors

and their color names.

Switch the cartridges to the correct positions.

Recommended Parts

None

45xx PQ Guide

Documents