Visual chart of HP LaserJet print defects
- William DeMuth
- Mar 4, 2019
- 11 min read
Visual chart of HP LaserJet print defects
This is a useful reference chart of images, showing a picture of each of the most common print defects found in laser printers. Use this guide to identify your print defect, and read more about the print defect with potential causes and solutions.
Below is a chart of common print defects found in laser printers. It is not a complete list but should cover 90% or more of the most common image defects. Click on the defect for more info on potential causes and solutions:
Background scatter
Possible Cause -Solution
Toner cartridge is defective - Install a new toner cartridge
Fuser assembly is bad - Do a half-way test to determine if it is the fuser
Transfer Roller is dirty or worn. A worn Transfer Roller can cause background scatter due to improper bias voltages. - Replace the transfer roller.
Black lines - parallel or perpendicular
Possible Cause -Solution
parallel or perpendicular If the lines are repeated at a consistent interval down the page, this is a repetitive defect.--See the Repetitive Image Defect Ruler in the service manual to measure and determine source of lines.
Black page
Possible Cause -Solution
Defective toner cartridge --Install a new toner cartridgeblack pages
High voltage power supply circuit is defective (not supplying the correct negative voltage)--Replace the High Voltage Power Supply PCA
DC controller PCA is defective. If the DC Controller turns on the laser beam continuously, the entire surface of the Photosensitive drum is neutralized causing a completely black page.--Replace the DC Controller PCA
Blank page
Possible Cause -Solution
Occasional Pages
Multiple feeds--The printer may be feeding two or more pages at once because the paper is difficult to separate. Flex the paper a bit to help separate before installing in printer.
Software configuration ,. network configuration--Re-install printer driver. Check paper size settings in software. Check any software/network settings related to printing a blank separator page between jobs.
Malfunctioning paper pickup assembly--The paper pickup solenoids can misfire and intermittently cause the pickup rollers to rotate an extra revolution. This will cause a blank page. Replace or repair paper pickup solenoids.
All Pages
No toner is available for print--Remove sealing tape on toner cartridge, or replace the toner cartridge if necessary.
Malfunctioning laser shutter--Perform a half-way test and see if there is an image on the imaging drum. If there is no image on the drum, check the laser shutter for correct operation when inserting the toner cartridge
No transfer roller voltage--Perform a half-way test and see if there is an image on the imaging drum. If there is an image on the drum, make sure the transfer roller is installed. Without transfer roller voltage, toner cannot be attracted from the surface of the drum to the print media. Replace the transfer roller if necessary.
No developing bias--Perform a half-way test and see if there is an image on the imaging drum. If there is no image on the drum, clean the high-voltage power supply contacts. With no developing bias charge, toner is not attracted to the drum. Replace the engine controller board if necessary.
Defective laser scanner cable--Perform a half-way test and see if there is an image on the imaging drum. If there is no image on the drum, low-level signals exchanged between the laser/scanner assembly and the engine controller board could theoretically affect laser output. Replace the laser/scanner cable assembly if necessary.
Blank spots
Possible Cause -Solution
Defective toner cartridge--Replace the toner cartridge.
Dirty laser scanner mirrors--Clean the laser scanner mirrors. On some models, this is an advanced procedure; consult the service manual for instructions on accessing the laser scanner assembly.
Contaminated or deformed transfer roller--Replace the transfer roller.
Bubble print
Possible Cause -Solution
Defective toner cartridge--Replace the toner cartridge.
Defective High Voltage Power Supply--Replace the High Voltage Power Supply
Photosensitive drum inside toner cartridge is not grounded--Check for proper mounting of the High Voltage Power Supply, and the HVPS ground contact on the toner cartridge. Check for proper seating of toner cartridge. Replace toner cartridge.
Paper does not meet specifications -- moisture content, conductivity, or surface finish may not work correctly with the electrophotographic process.--Try a different paper type
Compressed print
Possible Cause -Solution
Drive gear is broken or worn--Inspect and replace the worn gear of assembly
Toner cartridge bushings are too tight--Replace the toner cartridge
Contamination on back
Possible Cause -Solution
Contamination inside printer--1. Print at least 10 pages to see if the problem goes away on its own. 2. Print a cleaning page (consult User's Guide/ Service Manual.) 3. Identify and clean the contaminated part, or better yet, replace the contaminated part if replacements are orderable. 4. If contamination continues, check toner cartridge for leaks. Replace cartridge.
Print media does not meet printer specifications, or is stored improperly. 1. Print a few more pages to see if the problem corrects itself. 2. Turn over the stack of media in the tray. Also try rotating the media 180 degrees. 3. If the print media does not meet HP specifications, replace the paper, and advise the customer to use the recommended print media and store it properly.
Creases
Possible Cause -Solution
Paper is loaded incorrectly.--Make sure print media is loaded into tray correctly, and that the tray guides are adjusted properly to fit against the paper stack.
Determine the cause by performing a half-way test to isolate the defective component.--Replace defective component. Common possibilities include slipping paper pickup assembly, slipping feed assembly, slipping fuser assembly.
Curl
Print media does not meet printer specifications or is stored improperly.--1. Print a few more pages to see if the problem corrects itself. 2. Turn over the stack of media in the tray. Also try rotating the media 180 degrees. 3. I the print media does not meet HP specs, replace the paper.
Wrong fuser setting for print media type--From the paper-handling menu on the control panel, change the fuser mode setting or choose another paper type from the printer driver.
Wrong output bin--Print to a different output bin (top or rear output bin).
Distorted image
Possible Cause -Solution
Defective engine controller board--Replace the engine controller board
Defective laser scanner--Replace the laser scanner
Poor connection of cables to the engine controller board--Reseat the cables connected to the engine controller board
Print media does not meet printer specifications or is stored improperly--1. Print a few more pages to see if the problem corrects itself. 2. Turn over the stack of media in the tray. Also try rotating the media 180°. 3. If the print media does not meet HP specifications, replace the paper, and advise the customer to use the recommended print media and store it properly
Dropouts
Possible Cause -Solution
Failing toner cartridge, or wrong toner density setting--Replace toner cartridge, or wrong toner density setting
Failing upper fuser roller in fuser--Replace fuser
DC Controller is defective (low primary voltage)--Replace the DC controller
High Voltage Power Supply is defective--Replace the high voltage power supply
Transfer roller is defective--Replace the Transfer Roller
Faded print w. bubbles
Possible Cause -Solution
Toner cartridge drum not grounded properly--With no ground path, the drum cannot discharge. The negative charge on the drum repels toner and leaves a white page with bubble print. 1. Replace toner cartridge. 2. Check the drum ground spring and reconnect it, if necessary. 2. Replace the engine controller board
Fading print
Possible Cause -Solution
Toner supply is low , failing--Shake the cartridge gently to redistribute the toner, or replace the cartridge
Transfer roller is defective or incorrectly installed. If the Transfer roller loses conductivity, it cannot effectively pull toner from the drum to the paper--Inspect the Transfer Roller for proper installation and contact. If the Transfer Roller is damaged, replace it
Laser mirror is dirty or shutter is not functioning--Clean the scanner mirror. Check the Laser/Scanner shutter door for proper operation. If defective, replace the Laser/Scanner Assembly.
Print density is set incorrectly--Change to a darker setting and retry printing
EconoMode is on. (EconoMode saves toner by reducing the dot density. This may appear to be a print quality problem in some cases.)--Turn EconoMode off. EconoMode settings are stored in either the printer driver or the job application.
Faulty Registration
Possible Cause -Solution
Paper guide on the paper tray is incorrectly adjusted.--If the guide is pushing too tightly against the paper, it may be delayed in being pulled into the printer. If the guide is too loose, it may cause image skewing. Make sure that the paper guide is adjusted for the correct paper size and is locked into position.
Paper is being picked up skewed; worn pickup , feed, or registration rollers.-- Inspect all paper path rollers, looking for wear, cracks, or glazing. Replace worn rollers.
Paper tray is overloaded. If the tray is overloaded, the Pickup Rollers may not pick correctly.--Reload proper amount of paper squarely in the tray. Review paper loading with the customer.
Gray background
Possible Cause -Solution
Faulty toner cartridge--Replace the toner cartridge
High voltage power supply failure--Replace high voltage power supply
Formatter failure--Replace formatter
Wrong toner density setting--From the print-quality menu on the control panel, adjust the toner density setting.
Horizontal black lines
Possible Cause -Solution
Defective laser scanner assembly or engine controller board--1. See the “Repetitive defect ruler” 2. Reseat connectors on the laser scanner and engine controller board. 3. Replace the laser/scanner assembly followed by the engine controller board, if necessary
Horizontal smudges
Possible Cause -Solution
Paper path contamination or damage--1. See the Repetitive defect ruler. 2. Check the toner cartridge and replace it if necessary. 3. Check the fuser and replace it, if necessary
Horizontal white lines
Possible Cause -Solution
Defective toner cartridge--Replace the toner cartridge
Dirty / defective laser scanner assembly--Clean laser scanner mirrors. Replace scanner assembly if necessary.
Defective DC controller--Replace DC controller
Image skew Possible Cause -Solution
Pickup roller are worn. Paper is being fed at a skewed angle.--Inspect all paper path rollers, looking for wear, cracks or glazing. Replace worn rollers.
Paper size adjustment levers are not in correct position--Verify position of paper size adjustment levers, and correct
Paper is loaded incorrectly. If paper is not installed flush and tight in the paper tray, a skewing problem will result.--Remove paper from the tray, and install paper correctly. Position the paper guide correctly for the paper size being used.
Failing registration assembly--Replace registration assembly.
Light print, dark print, or fade
Possible Cause -Solution
Toner cartridge is low or failing--Replace the toner cartridge
Transfer roller was not installed correctly, or is defective--Reinstall transfer roller, making sure it is fully seated. Replace transfer roller if necessary.
Dirty laser scanner, or defective laser scanner--Clean laser scanner mirrors. Replace laser scanner if necessary.
Poor contact from toner cartridge to engine controller board, or failing engine controller board, or failing high voltage power supply--1. Ensure that the drum ground spring is connected to the engine controller board correctly. 2. Clean the contacts if they are contaminated. If the problem remains after cleaning, or parts are damaged or deformed, replace them. 3. Replace the engine controller board. 4. Replace the high voltage power supply.
Wrong toner density setting, or EconoMode setting--From the Print Quality menu, adjust the toner density setting. Make sure EconoMode is off
Loose toner
Possible Cause -Solution
Defective , failing fuser--Replace the fuser
Toner cartridge is defective--Replace the toner cartridge
Wrong fuser setting for paper type--Paper type settings control the heat of the fuser and bonding of the toner. From the paper-handling menu on the control panel, change the fuser mode setting or choose a different paper type from the printer driver
Toner spill contamination inside the printer--Print a few more pages to see if the problem corrects itself. Clean the inside of the printer or use the printer's cleaning page.
Paper type might be unusable (too thick, too smooth, etc).--Try an alternate paper type
Misshapen characters
Possible Cause -Solution
Defective , failing fuser assembly--Replace the fuser
Laser scanner assembly is defective--Replace the laser scanner assembly
Failing drive gears causing fuser rollers to "slip" when bonding--Listen for excessive drive gear noise; examine drive gears for wear. Replace if necessary.
Failing transfer roller--Clean or replace transfer roller
Paper surface is too smooth for proper toner adhesion--Try an alternate paper type with different surface
Paper surface is too rough; toner migrates to low spots and leaves higher areas void--Try an alternate paper type with different surface
Partial blank page
Possible Cause -Solution
Toner cartridge is failing--Replace the toner cartridge
Unseated transfer roller--Check transfer roller to ensure proper installation
Dirty laser scanner, or defective laser scanner--Clean laser scanner mirrors. Checker shutters for correct operation. Replace laser scanner if necessary.
Failing engine controller board, failing high voltage power supply--1. Ensure that the drum ground spring is connected to the engine controller board correctly. 2. Clean the contacts if they are contaminated. If the problem remains after cleaning, or parts are damaged or deformed, replace them. 3. Replace the engine controller board. 4. Replace the high voltage power supply.
Page is too complex or not enough memory--Memory overflow error should occur, or "page too complex" error. Try an alternate print driver. Add printer memory if necessary.
Repetitive defects Possible Cause -Solution
Defective toner--Replace the fuser if necessary.
There are a variety of causes for repetitive defects. --Check the repetitive defects ruler.--See repetitive defect ruler.
Skew
Possible Cause -Solution
Print media is not loaded correctly, or trays are not adjusted properly.--1. Make sure paper is loaded straight/neatly/correctly. 2. Make sure paper tray is not filled past capacity. 3. Ensure the paper guides in the tray fit properly against the paper.
Paper pickup / feed rollers are worn and feeding paper at a skewed angle--Check pickup / feed rollers for wear. If possible, print from a different tray / paper path to verify that only rollers in that path are failing. Replace worn rollers.
Registration assembly is failing--Replace registration assembly if necessary
Object blocking paper path---Check the paper path for obstruction
Laser scanner assembly is failing.--Replace laser scanner assembly if necessary
Tire tracks
Possible Cause -Solution
Failing toner cartridge--Replace toner cartridge
Contamination on paper pickup / feed rollers--Clean or replace rollers.
Toner smear
Possible Cause -Solution
Failing toner cartridge--Do halfway test to isolate the problem. Replace toner cartridge
Fuser assembly has toner buildup, or is failing.--Do halfway test to isolate the problem. Run some more pages to try to clear the toner buildup. If needed, replace fuser
Toner spill contamination in the printer--1. Print a few pages to see if the problem corrects itself. Clean the inside of the printer or use the printer's cleaning page.
Wrong fuser setting for paper type--From the paper-handling menu on the Control Panel, change the fuser mode setting or choose another paper type from the printer driver.
Defective DC controller. (DC controller regulates fuser temperature).--If a replacement fuser doesn't solve the problem, replace DC controller PCA.
Paper type may be unusable (too smooth, too thick, too rough)--Try a different paper type
Toner specks
Possible Cause -Solution
Failing toner cartridge--Replace toner cartridge
Toner spill contamination in the printer--1. Print a few pages to see if the problem corrects itself. 2. Clean the inside of the printer or use the printer's cleaning page.
Fuser assembly has toner buildup, or is failing.--Do halfway test to isolate the problem. Run some more pages to try to clear the toner buildup. If needed, replace fuser
Vertical black lines
Possible Cause -Solution
Defective toner cartridge--Very probably-- Install another toner cartridge or perform a halfway test to isolate the problem. Replace toner cartridge if necessary.
Worn , failing fuser film--Somewhat probably-- Perform a halfway test to isolate the problem. Check fuser film for tearing or wear. Replace the fuser if necessary.
Defective formatter generating a "video line"--Unlikely Replace formatter if necessary
Faulty DC controller or high voltage power supply-- Less Unlikely Replace DC controller , high voltage if necessary
Vertical dots
Possible Cause -Solution
Defective toner cartridge--Replace toner cartridge
Defective engine controller board--Replace engine controller board
Deformed or deteriorated transfer roller--Replace the transfer roller
Faulty DC controller or high voltage power supply--Replace DC controller , high voltage if necessary
Vertical white lines
Possible Cause -Solution
Failing toner cartridge--Very probable Try gently shaking the cartridge to redistribute the toner. If the problem continues, replace the toner cartridge.
Contamination in the laser path--Somewhat probable 1. Clean the laser scanner mirrors and lens. 2. Replace the laser / scanner assembly.
White spots on black
Possible Cause -Solution
Defective toner cartridge--Replace the toner cartridge
Defective high voltage power supply (HVPS) or fuser.--1. Print a few more pages to see if the problem corrects itself. 2. Make sure that print media type and quality meet HP specifications. 3. Make sure that the environmental specifications for the printer are being met. 4. Replace the toner cartridge, HVPS, or fuser.
White stripes parallel to path
Possible Cause -Solution
Failing toner cartridge--Replace the toner cartridge
Failing transfer roller--Replace the transfer roller
Other Helpful Resources
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