How the toner cartridge completes the laser printer imaging system?

Photo by Makenosound

The imaging system of a laser printer is a toss-up between the OPC photoreceptor drum and the laser scanning assembly. After the image is formed on the OPC drum, toner powder is introduced simultaneously. Through the action of static electricity, toner literally jumps into the paper media and the whole (paper and toner) thing moves into the fuser to permanently bind toner to paper. The laser printer component responsible for supplying a sufficient amount of toner to the photoreceptor drum is the detachable toner cartridge.

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Troubleshooting Print Defects: When the Drum Unit is Suspect!

Troubleshooting print quality troubles for the HP LaserJet 2550 color laser printer based on a defective printout is a tough nut to crack. A laser printer is outfitted with several components; from mechanical rollers, to the photoreceptor drum, the toner cartridge and the fuser assembly. Each of these components is capable of inflicting toner smears on the printout. The only sure way to correct faulty prints is to pull out the suspect component responsible for pertinent print irregularities and physically check it for defects. However the process is tedious, because it involves ocular check-ups of selected, if not all components that come in contact with the paper (medium).

Measuring the Print Defect
Hewlett Packard however made troubleshooting for the HP 2550 so much easier with the use of a repetitive defect ruler. By measuring the actual dimension of the defect on paper (using a ruler), the ugly head of the suspect component can be identified. Since we are dealing with a defective OPC Drum, the repetitive defect measures 148.3 mm in length. Said measure actually indicates that such defect is produced by a defective photoreceptor drum. From thereon, the user simply needs to pull out the photoreceptor drum and physically assess its condition. If the defect is more pronounced, it has to be replaced and if defect is not visible, the drum probably just requires cleaning.

Replacing the Drum's Lockout Chip
Photoreceptor drums are designed with electronic based microchips or lockout chip that count the actual printed pages and consequently desist printing once the rating limit is breached. Standard capacity of the photoreceptor drum is from 6,000 to 8,000 copies at 5% coverage (the industry standard measure of page coverage) and the microchip nominally bars printing after the stated limit. However in cases where not a single defect manifests at the time printing stopped; it could only mean that the OPC Drum is still in fine form and the user will only have to change the lockout chip to commence printing.

Replacing the Drum Unit
On the other hand, if printouts have defects attributed to a defective OPC drum unit, a physical inspection of drum surfaces will not always be a sufficient indicator of the component's actual condition. A tear on its selenium coating is a visible defect (easily recognizable) but if the drum has lost its photosensitive properties, then no amount of physical inspection will be enough to determine what is really wrong with the component. In cases where the OPC drum is suspect and the defect persists, the only choice is to replace the OPC Drum.

Remember that while print defects are a regular fare for laser printers, most print quality troubles emanate from a toner low or toner empty, toner cartridge and seldom do these stem from faulty printer components. Defects attributed to toner empty cartridges can be resolved with the use of a compatible toner refill kit; where the supplied compatible toner powder is used to replenish the cartridge's toner supply. The bundled cost of OEM HP 2550 toner cartridges is around $350 with each cartridge having a capacity of 1,500 pages at 5% coverage. Read more about toner refill kits from our previous post.

For those operating on a shoestring budget, the compatible HP toner refill kit rainbow pack is retailed for less than $100 but delivers similar print performance and yield as the OEM toner.

Read a related post on How to determine if the laser printer drum needs to be replaced?

How to determine if the laser printer drum needs to be replaced?

The photoreceptor drum can be considered as the most important component of laser printer units. Its critical function involves the receipt of text and images from the laser scanning assembly and transferring the same to paper to produce the final print. Considering its functionality, the printer drum needs to be replaced periodically to continuously achieve commendable prints. There are a number of indicators that should inform the user whenever the laser printer drum is due for replacement, as follows:

Computer prompts the user. There are only a few printers; particularly colored laser printers, that alert users when the drum needs to be replaced. Usually, the alarm sets off in the form of a flashing message that materializes on the monitor. How convenient for users who operate these types of laser printers. Now they only have to wait for the warning message to set off.

Unclear or blurry printouts. At times, users will come across printouts that are unreadable while having streak marks over the surface of the printed page. This could be a sign that the drum is damaged and needs immediate replacement.

Presence of black spots on printed document. Unwanted marks over the printed page such as black spots indicate that the drum is defective and can no longer be used. This being the case, the user should purchase a replacement drum to be able to resume print jobs.

Light or faded text and images. A noticeable change in print out quality such as faded prints could imply that the drum is nearing the end of its serviceable life or that it is slightly damaged and needs replacing.

Blank printout. Laser printer drums have specified life spans based on the number of printed pages. Thus, when a blank printout is produced, this could only mean that the drum has reached its set lifespan and is due for replacement.

Keen observation is the key to knowing when the laser printer drum needs replacement. Note the abovementioned indicators and have a ready compatible drum replacement on hand to avoid print delays and continuously achieve quality prints.

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To produce decent laser prints and yield at a reasonable price, refill OEM toner cartridges with toner refill kits. The toner refill kit line of Laser Tek Services is cheaper by as much as 80% than the prevailing retail price of OEM toner cartridges.