Visual chart to identify and troubleshoot common HP laser printer image defects.
Image defects are defined as image abnormalities such as repeating specks, bands, or streaks down (or across) the page. Most defects can be traced to damaged rollers, broken gears, dirty mirrors, defects in the toner cartridge, or other common causes
This article describes the process of solving image related problems and clarifies the brief steps in the HP Image Problem Solving Table. Skip to the "circled" number from the table for a clearer understanding of the recommended action. If that action does not cure the image problem, return to the Image Problem Table for the next action step. If you have reached Step 14 (Call for Service), consider calling your local service company for help.
The numbers below correspond to the numbers in the right column of the Image Problem Table.
HP Image Problem Solving Table Instructions: 1.Closely examine the image problem. The Chart suggests solutions and defines them by name. 2.Locate the image problem by description or icon at the top of the chart. 3.Proceed down the column under your problem image to the first data mark (O). 4.Go to the right to the step number in the black circle on that row. 6.Do the action suggested for that row number. If you need more details, locate the "circled" step number in the next section. It will describe how to do what is listed in this step. 7.Return to the chart for more steps if the problem is not resolved.
1) Try again, see if the problem goes away.
Always double check the symptoms of the problem. If some one else has told you what has happened, run a test print of your own. Do your own diagnosis. Sometimes the image problem changes for the better. For example, if a small quantity of toner dropped from the toner cartridge due to mishandling, things may clean up after a few prints or so. If the problem remains or worsens, go back to the Image Problem Table for the next step.
2) Adjust print density. (light prints, background, shading, ghosting)
Each HP LaserJet has a print density adjustment. For best image quality, this adjustment should be set to the value recommended for the toner cartridge used. Improper print density settings could result in poor image quality: light printing, background, or gray shading over the entire page. Using a mid density setting of with a graphics quality toner cartridge could cause ghosting, a condition in which extra toner deposited on the page transfers onto the fuser roller, hen back on to the page again.
To override printer console settings, set the print density from your P'C through the printer driver or printer control panel. The manufacturer sets the value to the middle setting as a default. Selecting the print density by this means is beyond the scope of this book. We suggest that in either case you may need to see your PC or software manual for details.
Always use the recommended print density setting as specified by the cartridge manufacturer. If unknown, select the midrange for the next test. Try again and see if the problem goes away. If not, return to the Image Problem Table for more ideas
3) Try standard bond paper. (ghosting, lines, streaks, voids, light prints, background, shading, creasing, wrinkles, other defects)
Using paper for which the machine was not designed might create print defects. For example, preprinted letterhead produced using low temperature toner leads to ghosting as the page moves through the printer fusing assembly. When ordering letterhead, stationery, envelopes, or other preprinted media, make sure your commercial printer knows you will be using this in a laser printer.
Paper stock, made for other than laser printer use, might not accept toner well over part or all of the page. Fading, spotty images, voids or dropouts, light image formation, repeating defects, are among the possible defects related to improper paper Thin paper stock, envelopes, overhead film, and other nonstandard media could create other problems like creasing, wrinkling, folding or others.
Printers with straight-through paper paths such are more tolerant to a wider variety of media. In fact, some HP laser printers enable users to alter the fuser temperature for certain media other printers can't handle.
Moisture in paper produces voids or blank areas where the image should be formed.
Be prepared to test a machine exhibiting such problems using standard bond paper, fresh from a newly opened ream. Remember paper plays an important part in the process. Be alert to changes in paper supplies, especially preprinted stocks.
If the problem remains after running fresh paper, return to the Image Problem Table for more possible causes of the symptom encountered
4) Ensure cartridge seal is out. (fading streaks, white lines, blank pages, light prints)
OEM cartridges and those from quality remanufacturers are sealed to prevent toner leakage during handling and shipping. Instructions in the packaging shows you how to remove the seal before installing the cartridge. Ensure the toner cartridge seal has been removed before calling for help.
Protect yourself from loose toner when removing the toner cartridge seal. Hold the cartridge over a trash basket. Firmly grasp the seal and pull steadily away from the cartridge until the seal is about to drop. While steadying the cartridge in one hand, keep your distance as the seal drops from the cartridge. Discard the seal. After the seal has been removed, gently rock the cartridge before installing it into the machine. See solution Step 6 on for more details.
5) Gently rock to cartridge and reinstall. (fading streaks, white lines, light prints)
Faded printing, voided bands, white lines and other defects indicate that the toner cartridge might be running out of toner. By gently rocking the toner cartridge, toner spreads out on the developer roller more evenly, resulting in a more even image. Be ready to install another toner cartridge because this is only a temporary solution.
Before installing a new toner cartridge, remember to gently rock the cartridge after removing the cartridge seal. See details under Step 4)
For other possible causes of these print defects, see the Image Problem Table
6) Try Another Toner Cartridge. (lines, streaks, light prints, shading, specks, other image problems)
Having another toner cartridge to test with is wise. Since no two toner cartridges are likely to produce the exact same print defects, another cartridge would help define whether the problem involves the cartridge or printer. If the original image problem goes away when testing with another toner cartridge, the problem is likely cartridge related.
All toner cartridges develop problems eventually: They all run out of toner, unless premature problems develop such as a scratched or worn drum, nicked wiper blade, or other defects. For example, a nicked wiper blade usually results in a sharp, black line along the direction of paper travel.
We occasionally hear that a toner cartridge leaked toner in the printer, resulting in blobs or "bombs" of toner on the page. Whether the toner actually leaked or was drawn out by errant static electrical charge might be questioned. The toner cartridge, as the heart of the image formation process, uses static electricity to form the toner image on its drum. If static charges in the printer develop where they don't belong, toner could be attracted through open spaces by statio charges-helped by gravity-onto the paper path below. The high voltage power system of a laser printer is complex. Static charges could be diverted, especially in printers which are poorly maintenance.
Chances of averting problems like toner leakage are regular, professional printer cleaning and maintenance improved with Toner leakage might also be caused by mishandling toner cartridges. Remember to handle a toner cartridge with care. Never shake a cartridge, rock it gently to distribute toner evenly within the hopper. Shaking after the seal has been removed will likely result in spills and poor image quality.
For your convenience in pressured times, always have a spare toner cartridge for backup.
For other possible causes of these print defects, see the Image Problem Table.
7) Check that environmental conditions match specs.(lines, streaks, voids, light prints, background, repeating defects, deformed paper)
HP specifies the environmental operating conditions under which its printers work best, including temperatures from 50 to 91° F and relative humidity from 20 to 80%.
Generally, most print defect problems occur under extremes of temperature and humidity. Low-humidity (hot or cold) conditions tend to produce background or gray hazing on printouts. Hot, high humidity conditions often produce light, washed out printouts.
Do you repeatedly experience paper jams on days when static goes through the roof? Try grounding the printer to a good grounding point in the room. Ungrounded static charges cause static cling like socks in a dryer. In this case, paper in a printer clings to the paper path rollers and guides rather than moving smoothly to the printer exit.
Environmental conditions also contribute to paper deformation, voids, light printouts, background, and other problems. High humidity accumulates moisture in paper, inhibiting its charge acceptance which results in incomplete transfer of the image to the page.
Have another fresh, unopened ream of paper handy for days like these to test for resulting print or paper deformation.
Another factor which influences printer performance (therefore, print quality) is air quality. Printers used in dusty or smoky environments build up dirt on critical image forming structures like scanner lenses and mirrors. These structures are accessible on some printers and not on others. Depending on which model printer has the problem, covers and scanner boxes must be removed for cleaning. For other possible causes of these print defects, see the Image Problem Table
8) Check fuser packing spacers or levers. (unfused toner on one side or over the entire page)
Older laserJets using conventional heated roller fusers come from the factory with packing spacers or release levers, separating the upper and lower pressure roller. Their purpose is prevent flats spots pre installation.
9) Check fuser for damage (if possible). (lines, streaks voids, gray shading, repeating defects, unfused toner, image distortion, or deformed paper)
Scored or damaged fuser rollers cause print defects. On some printers it is possible to see the damage and confirm the need for repair. On others, removing and inspecting the fuser is required.
Conventional fusers use a Teflon-coated polymer sleeve, heated from within by a ceramic heating element. A silicon rubber lower pressure roller squeezes the paper-with image resting on top-up against the fuser film sleeve to fuse the image to the page. Heat and pressure working together. The Teflon keeps the toner and paper from sticking to the film sleeve.
Devices sensing roller heat or keeping paper from curling up with the heated roller, collect dirt, debris, toner, and paper dust. When the machine cools after shutdown, this material hardens on the devices. After starting up and cooling down many times, the Teflon begins to separate and peel from the heat roller. Areas where the Teflon disappears fail to fuse the toner onto the page, leaving smears, or repeating marks along the page in its direction of travel through the printer.
Observing the condition of fuser rollers of other LaserJets usually requires removing the fuser. Although this might only require removing a few screws, you may want to leave this to a qualified technician.
For other possible causes of these print defects, see the Image Problem Table.
10) Ensure ECONOMODE is OFF. (light prints on entire page)
ECONOMODE is an option which can be selected either from the printer control panel or from the PC computer. Only models since the LaserJet 4 have this option. Economode saves toner while running proof printouts to fine tune documents. Images printed under this mode typically emerge very light-often too light to be usable.
Persons unaware of the consequences turn the feature on, then complain about very light printouts. They might think something is either wrong with the toner cartridge or the machine. Often, even knowledgeable technicians are misled into thinking the machine has a high voltage power supply malfunction or other problem.
Therefore, if light printouts emerge, we recommend running a self test page first, checking to see if the option is on or off. Enable or disable ECONOMODE through either the control panel or the computer printer driver.
For other possible causes of these print defects, see the Image Problem Table.
11) Ensure PowerSave is OFF. (ghosting)
PowerSave when turned ON-reduces printer power consumption. Unfortunately it sometimes contributes to ghosting on HP printouts. Ghosting means certain parts of the image repeat elsewhere on the page, where they don't belong. Most HP Laserjet models don't seem to be as effected by PowerSave settings.
Older fusers, use lots of power to keep the heated fuser roller at standby temperature, waiting for the next print job. PowerSave shuts off the fuser lamp after a period of inactivity-usually 15 or 30 minutes- which conserves energy. After cooling down, the fuser must start warming up from room temperature for the next printing.
Unlike normal machine start-up which initiates engine a logic checks as well, PowerSave ON initiates fuser heating only The first page after PowerSave start-up sees higher-than-normal heat. Some overheated toner sticks (offsets) to the upper fuser roller As the roller continues to turn, the offset image again contacts the page and causes ghosting.
Fuser heat stabilizes after a few pages, but ghostly images on the page might continue. The problem may get better depending on whether toner built up on the fuser fully transfers to the pages. In most cases, continued toner buildup on the upper fuser roller requires cleaning or replacing the fuser, which may require the services of a technician.
Certain toner cartridge and fuser combinations aggravate ghosting. Age of the fuser seems to be directly involved: The older the he more prone to develop ghosting.
Energy conscious users can set PowerSave to three hours. That eans only after three hours of printer inactivity will the fuser shut down. For printers likely to be used more often than once every three hours, this would be a good setting for PowerSave ON. Otherwise, to decrease the likelihood of ghosting, turn PowerSave OFF on or off, and for how long, if on
To find out if PowerSave is run a self test for the printer. If PowerSave is ON, try turning this feature OFF.
12) Clean or replace transfer roller assembly (white lines or streaks; linear voids; blank pages; light prints on entire page, uneven or faded areas on page)
A dirty transfer roller assembly degrades the performance of the machine, usually creating light streaks, bands or voids in the direction paper moves through the machine. Cleaning the transfer area often corrects these problems.
HP LaserJets printer use a transfer roller to draw the image onto the page. Proper cleaning of the transfer roller requires removing it from the printer. When doing so, be careful not to touch the black roller surface. Use rubber gloves if available. Oils from your skin degrade transfer roller performance.
Some LaserJets come with a tool for removing the transfer roller The accompanying figure shows how to hook the tool under the shaft at the left end of the transfer roller. Pull up to unhook that end. Grasp the shaft pull up slightly and to the left to uncouple the other end of the transfer roller shaft from its bushing. After the right end of the shaft is free, remove the transfer roller for cleaning.
We recommend blowing off the roller using compressed air or vacuuming it off. Don't use solvents to clean the transfer roller! The spongy rubber roller will absorb solvents, and later transfer them back onto the page. Replace the roller if its color has faded to light gray or white. The user maintenance kit for your machine contains a trans fer roller and other parts to be changed at the appropriate page count.
TROUBLESHOOTING TIP: One trick service technicians use to troubleshoot image problems is to shut the printer off in the middle of printing. Providing the paper stops under the cartridge drum, part of the image will be developed on the drum for inspection. Remove the toner cartridge and gently pull the cartridge shutter aside.
Observe the developed image on the drum. On one side of the strip, the image should look fully developed-dark and clear. The other side of the strip should look very light where little remains of the original image after trans- fer. If the image shows the problem as it rests on the pre-transferred part of the drum, the solution likely lies with the toner cartridge or units positioned above the cartridge (optical mirror or laser scanner). If the image looks perfect on the drum look at the transfer area or fuser for the cause
13) Clean printer optics and paper path. (white lines, streaks, voids, light prints, background, repeating marks, smearing, or wrinkled, creased paper)
Dirt or smoke collecting on optical surfaces or obstructions along the paper path create common problems within laser printers We occasionally find printers in service in some dirty places: construction sites, horse barns, saw mills, and others.
Air, drawn into the printer, deposits dust in critical locations, blocking laser light from reaching the photosensitive drum of the toner cartridge Machines need periodic cleaning and maintenance for peak performance.
Basic cleaning of most laser printers involves:
Removing the toner cartridge
Checking for loose or missing screws
Wiping or vacuuming dirt and dust from inside
Cleaning the transfer area
Cleaning cartridge electrical connections
Cleaning beam mirror (if accessible)
Cleaning feed rollers
Checking and cleaning paper trays/cassettes
Running a self test
Often this can be done in under fifteen minutes. For other possible causes of these print defects, return to the Image Problem.
14) Call for printer service. (for all unresolved image problems)
By following the steps listed above, we hope that many image problems will disappear. When all the steps listed do not resolve the problem, you may need some help.
Other Helpful Resources
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