Good evening. Thanks for using JustAnswer. I'm XXXXX XXXXX, a/k/a "DrKlahn."
Have you checked the "Draft" or "Economy" setting for the printer? This results in the printer skimping on toner to produce barely acceptable printout good only for previewing a printout. Below is an example for an HP Laserjet 1100 showing the "Economy" setting (highlighted in green) disabled:
If the printer is not in "Economy" mode, then the next most likely issue is that the high voltage is failing to transfer all the toner from the drum/belt to the paper. This can be checked by looking for excess toner inside the casing and "ghosts" further down the page. Unfortunately, confirming that possibility is an issue for an HP technician with the service manual, because it requires special equipment and the high voltage is potentially lethal without proper precautions.
Another possibility is a worn drum or belt. However, all modern laser printers warn when the drum or belt is reaching the end of its life, so this is not as likely as a high voltage issue.
Check the Economy settings for the printer first. If the printer is in normal mode, then I advise having an HP technician look at it.
Under JustAnswer rules, this comment qualifies as an Answer and I am required to post it as such. However, do not Accept it if this does not resolve the problem.
If anything in this answer is unclear, or you'd like something explained in more detail, don't hesitate to ask.
If this answer is satisfactory and solved the problem, please click "Accept." I am only paid for answers that are Accepted; otherwise, I receive nothing. Feedback about the quality of an answer is always welcome.
If this answer is unsatisfactory, please do not accept it. Let me know why, give me a chance to correct it, and let me know how I can do better in the future.
Remember: Further discussion is always possible, even after an Answer has been accepted.
It's not in economy mode. Color print quality has just slowly eroded to when colors are faded.
I see. This indicates a hardware problem, then, most likely the high voltage.
Now here is the catch in having an HP technician service the unit.
Except for business-grade workgroup printers, few modern printers are repairable, and fewer are worth repairing. It is unfortunate that printers are now manufactured to a "replace not repair" standard. To understand why this is the case, consider the cold, hard, real-world cost of having a printer repaired.
In most repair facilities there's a two hour shop time minimum charge, with technician time at $US 100/hour. Then comes the cost of parts - figure a $US 50 minimum for parts. The minimum cost of having a printer repaired is $US 250. Then add another $US 40 for shipping if the repair must be sent off to be fixed at a regional repair center outside your local area.
The rule of thumb for repair vs. replace is repair only when the repair cost is less than 2/3 of the cost of replacement. Therefore, if you can buy a replacement printer for $US 350 or less, you're better off with a replacement printer.
In most cases, ebay is a good source for replacements. Used, refurbished and NOS ("New Old Stock") printers are generally available for all printers made within the last ten years. An identical replacement has several advantages:
1. Continue using the same printhead or toner cartridge (assuming it is removable, of course) and keep the replacement's unit as a spare.
2. Use up the ink / toner cartridges from the old printer.
3. Continue using any expendable supplies such as ink tanks or toner cartridges from the old printer.
4. Eliminates the need to remove existing printer software and replace it with different software -- always an "iffy" issue.
At present the 2605dn is selling on ebay for between $45 and $250, delivered. See the ebay search below:
I advise looking into replacing the printer with a good used unit rather than repairing it, unless you can get your local HP authorized service depot to estimate the cost of repair without charging you for an estimate.