Common Cartridge Failures
OPC Drum Failure
The most common cartridge failure is predominantly due to the drum. The drum has the wiper blade scraping any excess toner off the surface as well as the paper or Transfer Belt rubbing against it as it prints. Common OPC drum failures are:
Perfectly straight and very thin vertical line running full length of page:
Indicates a scratched/ringed drum generally from foreign matter or build up of toner on the Wiper Blade, which scratches/rings the Drum during rotation.
Dots that repeat equidistance down the page:
Indicates a chip in the drum surface, referred to commonly as a “pinhole”. The distance between the dots is dependent on the circumference of the drum (generally 4 times). Some pinholes, on closer inspection, can be built up foreign matter which can be removed/cleaned with a cotton tip and Iso-Propyl alcohol.
Dots that repeat equidistance down the page, some are accompanied with a full horizontal band across the page:
The dots indicate a pinhole and the band across the page. Indicates a short/spike against the PCR, which is due to the pinhole.
Smears of toner across (horizontal) page and are equidistance apart (vertical):
Caused by light damaged drum coating (sunlight). The distance between the smears is dependent on the circumference of the drum, generally 4 times. Exposing the Drum to direct light for long periods of time damages the coating/film.
Full thin line across the page, equal distance apart:
Calculate the circumference of the drum and if the thin lines are the same distance apart as the Drums circumference then the Wiper Blade has marked the Drums coating. This generally occurs with periods of time where the WB rests against the drum (storage). Heat can play a role in this.
Grey “tyre tracks” on right or left side of page:
This failure is also sometimes described as wind blown sand. It is caused by a worn out drum. Drum coating or film starting to wear thin
Wiper Blade Failure
The next most common laser cartridge failure to occur would be due to an issue with the Wiper Blade. After the image is transferred from the Drum to paper or Drum to Transfer Belt there will be residual waste toner on the Drums surface which needs to be cleaned before the next revolution of the Drum. The Wiper Blades job is to collect/clean/scrap any residual waste toner from the Drums surface, depositing it into the waste toner hopper.
Thin line down the page:
This is caused by a cut or nick in the blade which fails to collect/clean/scrape toner from the drums surface
effectively leaving a lined mark down the print. This can also be attributed to a worn blade.
Grey page with toner visible on drum:
The Wiper Blade isn’t applying adequate pressure to the drum to successfully clean the residual toner from the drum, which then gets applied to the next revolution of print. This is often due to the Wiper Blade not being correctly fixed in place (not screwed down properly, incorrect sealing foam etc).
It can also be caused by and old wiper blade that has gone hard over time. The stiffened blade does not apply adequate pressure to the surface of the drum limiting the collecting/cleaning/scraping capability of residual toner. An indicator of an aged Polyeurethane Wiper Blade is a yellow tinge.
Poorly lubricated blade, seizing drum revolution:
The Wiper Blade constantly applies pressure to the Drum, if the blade is poorly lubricated will stick to the drum and travel in the same direction. Once the Blade has flipped it will apply immense pressure to the drum often seizing it completely or requiring a fair amount of force to turn. Generally this will be accompanied by a loud clicking noise from the printer, thankfully the printer has a clutch to prevent stripping of gears. You will see some compatible colour cartridges using Yellow toner as a lubricant, the Yellow toner tends to be finer/smoother and works quite well as a form of powdered lubricant.
Magnetic Roller Failure
The Magnetic Sleeve is a coated aluminium roller that transfers the toner from the supply chamber to the drum by use of magnetic attraction; to break it down the Mag Roller sleeve encases a Magnet in the same shape as the Mag Sleeve. There is an electrical contact at the end of the sleeve to which a charge is applied to amplify the magnetic attraction. The (generally) black conductive coating found on the Mag Sleeve is made of various conductive materials with the sole aim of carrying the toner. Most failures are usually due to scratches or excessive wear of the coating. Toner particles in general are abrasive, when combined with pressure from the doctor blade doctoring/pressing toner against the Mag Sleeve roller causes wear to the coating. Some cartridges use a Developer Roller in place of a Magnetic Roller, this piece will be covered in a separate fact sheet to come.
Light print:
A worn out magnetic roller is probably the main reason for a light printing cartridge to occur. There is a black conductive coating that wears off
the sleeve over time. If the coating on the Mag Roller were to wear thin or completely through, you would be able to visually sight the black conductive coating turn pale (wearing thin) or even revealing the under aluminium tubing. This type of failure will show up more on solid black areas and grey scales. Normal text wouldn’t normally reveal this type of issue.
White voids in the print:
This is caused by scratches or gouges in the coating of the Mag Sleeve. Normally one or two scratches wouldn’t pose a problem however the more scratches there are then the more potential voids there will be. This is especially true when the scratches are all in the same general location.
Light and dark banding across page:
This is caused by a bent or warped magnetic roller. This normally happens when a hub (especially the metal ones) is pressed into the sleeve at an angle. Metal hubs should be removed and replaced with a special press or with delicate care.
Intermittent printing:
A Mag Sleeve contact transfers charge from the printer to the conductive black coating on the surface of the Mag Sleeve. If the contact is bent out of shape, too much electrical grease applied or installed incorrectly it can print either light or blank pages (most often blank).
PCR (Primary Charge Roller)
The PCR is a roller which controls the charge being applied to the Drum Cylinder. Basically it places an initial uniform charge on the drum then towards the end of the cycle erases the residual charge once more applying a uniform charge. This leads into the next print cycle (each revolution of the drum is considered a ‘cycle’). Because of this dual role, there are some severe failures which can come from the PCR. Most of these failures will show up more in winter where the humidity is low rather than in summer when it is high (this is due to Static build up).
Ghosting:
Ghosting is commonly known as repetition of print already applied to the page (duplication). It is more commonly seen replicating dense print however can repeat all density levels depending on the severity of additional charge (the replicated print is produced in lower density almost producing a silhouette replication of the print, hence the descriptive term ‘Ghosting’). A ghosting issue in general is derived from a charge related problem. This can occur when the outer coating of the PCR is faulty (too much cleaning fluid) or too much conductive grease is applied to the PCR Clips/Housing.
A cut or hole in the PCR:
This results in a repetitive black mark at equal distance to the circumference of the roller. Sometimes these marks can short out across the Drum Cylinder creating excess charge across the drum attracting additional toner when produces a dark ‘band’ horizontally across the page. The markings and ‘bands’ will be repetitive in nature (7+ repetitions down the page).
Random dots across the page:
These can either be black dots, or white dots in black areas. This is caused by excess lubrication powder sticking to the PCR. These dots will be repetitive in nature depending on the circumference of the PCR (7+ repetitions down the page).
Vertical marks on print, generally found on the LHS or RHS of page:
If the cartridge is still fresh and markings appear on the print in a blob or smear like fashion, generally this means the PCR has been marked with conductive grease. Commonly it will be located on the LHS or RHS of print near the PCR Clip/Housing (accidental conductive grease application to PCR coating). If continual printing is done, the grease will smear and transfer to the Drum
effectively giving a poor print vertically in the smear zone.
The Developer Roller
A Developer Roller is a metal shaft covered in Silicon Rubber with a specially designed surface coating. Both the coating and Silicon Rubber help in storing and releasing electrical charge. The Dev Roller is much like a Magnetic Roller, as they both help in the transferral of toner from toner supply chamber (hopper) to the Drum. The main difference between the two is how they deal in attracting and repelling toner; a Magnetic Roller utilises Magnetic Charge, where as a Developer Roller utilises electrical charge to attract and repel. Magnetic based toner will use a magnetic roller, if the toner is charged then a developer roller is used.
Light Printing:
A worn or dirty Developer Rollers’ surface coating is often the issue for a light print to occur. The Coating wears off
over a period of time and can be accelerated from other factors, such as environment (heat), inadequate Doctor Blade pressure or incorrect/dirty surface coating material. This type of failure will show up more on solid black areas and grey scales. Normal text won’t easily reveal this type of issue unless severe. Essentially less toner is attracted to the Developer Roller than normal.
Dark or Excessive Print:
Dark or excessive print on the page can be due to incorrect cleaning products being applied to the Developer Roller. The surface coating is a fragile balance of components/materials to aid in attracting or repelling specific toners. This balance can be disturbed when cleaning products are applied, which strip or leave additives (residue) on the surface coating. Majority of cleaning materials (looking at you Iso) are too harsh and end up stripping some of the coating. This allows the Dev Roller to overcharge causing excess toner to be attracted – which leads to dark or excessive prints.
Repetitive coloured marks equal distance down the Print:
Repetitions measured at the same circumference as the Developer Roller (smaller circumference) will indicate the Dev Roller has been marked. This can occur from sudden force damaging the surface coating of the Developer Roller
Repetitive coloured horizontal lines equidistance down the Print:
Repetitive lines measured at the same circumference as the Developer Roller (smaller circumference) will indicate the Dev Roller has been marked. This generally occurs from gradual force from the Doctor Blade pressing into the Developer Roller eventually pitting the roller out of shape.
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