Information is the Key
It’s important to be familiar with each model of Lexmark printer that you maintain or repair. Study and compare the fuser drawings and you’ll find many of the design elements are the same. However, differences in print speed require different lamps, backup (pressure) roller sizes, heat roller construction, thermal fuses, and thermisters. And although the lamp contact assemblies are basically the same, their installation can vary widely. Notice also that some fuser elements vary within a given model according to the Printer Type Number (last 3 digits after the engine number found inside the front cover). These differences are important for image quality, and therefore, customer satisfaction. If there’s enough design deviation the result will be a 920 series Service Error Code. If not, the result will be service calls to adjust paper and fuser settings, dissatisfied customers and a shortened fuser life.
Lexmark Service Bulletins are an excellent source of information. For example, Bulletin #T65x 114 has good information on accordion type jams inside the fuser. I’ve included the section “Changing the type of fuser unit installed (T65x and X65x Series printers only) below. If you’re an Authorized Service Provider (ASP) Lexmark will email service bulletins to you directly. If you’re not an ASP they are available, on a limited basis, at the “Support/Download” part of Lexmark’s website. Also, check this blog and others like it, these experts should have this stuff memorized.
The following paragraphs are intended for your information.
They contain little things I’ve learned over the years on the job and from other techs. There is no intention, implied or otherwise, to try to tell anyone how to troubleshoot or repair any printer. I think there is some good information that worked for me at one time or another and hopefully it’ll work for you.
Under the Fuser Wick Assembly Cover you’ll find either the Wet Wiper Assembly (early models; T52x through T62x) or the Fuser Wiper Cavity Cover (later models: T63x and later). If the Wet Wiper Assembly isn’t replaced regularly it becomes caked with excessive toner and causes scratches on the heat roller. The Fuser Wiper Cavity Cover is ‘permanent’ so it’s not dependent on end-user replacement. Also, on the Fuser Wick Assembly Cover you’ll see tabs to hold the fuser wiper; brackets, if you will, designed to assist in the removal of the fuser wiper and avoid burns. I usually break them off as cleanly as possible (once the printer is out of warranty, of course). They will, over time, become very brittle and break on their own from the heating and cooling of the fuser during normal operation and from end user replacement of the cloth variety fuser wiper. Once they break, they end up on the heat roller causing scratches and/or in the fuser causing backup (pressure) roller damage and paper jams.
I mention the Wiper Assembly and Cavity Cover not only because they are causes for fuser damage but also because most end-users don’t realize there are 3 types: wet wiper and cavity cover discussed above; oil, for regular one sided labels; and wax, for duplex label printing.
These are the part numbers for the various wipers:
So before your next ‘print quality issue’ service call, go to the Lexmark website, click on Support and Downloads, then Tech Library, then Manuals and Guides (or just click here). Type Label and Cardstock Guide in the ‘filter’ box. Click the ‘filter’ button and print that guide. You and your customer will be glad you did.
When you receive a fuser check a few things:
- Check that the pressure wedges are in place. These are essential for Lexmark fuser storage. Without them even a brand new OEM fuser will have developed a flat spot on the backup roller that will make the printer sound like it’s about to come apart. Be sure to remove them before installation.
- Make sure the Narrow Media and Exit Sensors are functional, that the springs haven’t dislodged or the flag gotten pressed into the Lower Exit Guide Assembly.
- Ensure the internal wires are installed correctly, and that all the connectors, both internal and external, are firmly plugged in. And don’t forget the Fuser Guide Assembly at the front of the fuser. It needs to be straight.
And speaking of the Fuser Guide Assembly, this little gem will get caked on either side with excess toner. A telltale sign is a top corner of the printed pages being folded over. Many times you can remove the fuser, knock off the baked on toner pile with a small flat blade screw driver and the problem is solved. Look at the entire guide while the fuser is out and take off any other toner piles you might find along the other ridges.
This guide may also become warped, so check to make sure it’s installed correctly and that it’s straight. Look for a rise in the middle as this can cause accordion type jams in the fuser. And if any print jobs include stickers/labels, a warped guide condition makes it easier for the sticker to come off the backing paper and stick to the heat roller making a real mess.
The Fuser Guide Assembly is easy to replace without dismantling the entire fuser, if you’re careful. Prior to removal, make sure you have the right guide as a replacement (99A0713 for the Lexmark S series and 99A1591 for the Lexmark T Series). There are different styles and part numbers, so be sure you have the correct part before proceeding. If you’re not certain, remove the warped guide to compare the shape and mounting prong locations just to be sure.
To remove, just lift up in the middle and one side or the other will come loose of the mounting holes in the frame. If it doesn’t break, slide that side along the frame toward the front of the fuser. The other side will follow. To install a new guide, simply place one end in the mounting holes and lift up gently to slide it into place.
That thumping noise? It’s the pressure roller – almost every time, unless the customer is printing envelopes. When the printer starts to thump or make what has been described as a “galloping noise” you can almost bet that the fuser backup (lower pressure) roller has developed one or more flat spots. There is no cure for this but to replace the fuser (part numbers 56P2542 FUSER ASM,T630/T632; 56P2545-FUSER ASM,T634). Usually print quality isn’t an issue, at first. The most common complaint I’ve experienced is about the noise. However, if left unattended the results can be paper jams at the re-drive assembly, or incomplete fusing and toner smearing, or squeaking from improper fuser bearing wear. Many times the customer doesn’t even notice until you put a good fuser in and the noise stops. “It’s made that noise for as long as I’ve been here.” Now you’re a hero.
For the T630 and T640 series specifically, the heat roller can be an indicator for the need to replace the fuser. When the heat roller in these models turns blue, order another fuser because it’s going to start causing print quality issues soon. First it turns blue, then you’ll notice black spots that look like it’s been burned. Then the clear coating will start to peal off. When that happens, toner will build up on those places and cause print quality issues. Once again, the only fix is a new fuser.
It’s important to me to inform the end user how to remove a jam from the fuser. Flags get broken or damaged pulling paper the wrong way. Show them how to remove the back door (not the re-drive assembly) and where to look for paper. If they can get a hold of the paper, fine. But if they can’t, stress the need to call a service tech. It’s at that point the damage to the fuser will occur if they don’t. It’s been my experience that most people will recognize the difficulty involved in fuser paper jam removal and call before they do anything.
Also demonstrate why they should never take the toner cartridge out and pull the paper towards the front of the machine to remove it. Fuser Exit and Narrow Media Sensors are most often damaged by this action. Many times they can be fixed or replaced if you know how to disassemble and rebuild Lexmark fusers. But most of the time it’s easier and more efficient to replace the fuser.
Lexmark Bulletin T65x 114
I’ve included a portion of Lexmark Bulletin T65x 114 here. If you’ve ever filled out Lexmark Warranty info online you’ll no doubt remember seeing a choice of Type 1 or Type 2 fusers. I had no idea what the difference was. When I questioned my colleagues I was told to order the Type 1. It’s the most common and what they have always done. Well, now I have the definition and the reason why “That’s the way it’s always been done.”
Changing the type of fuser unit installed (T65x and X65x Series printers only)
If the jamming issues continue after replacing the fuser unit, installing a ‘Type 2’ fuser may help correct the issue. A ‘Type 2’ fuser unit uses detack fingers that come into contact with the fuser hot roll. This helps to prevent paper from sticking to the roller surface.
IMPORTANT! This option should be avoided whenever possible and used only in a case of last resort. The ‘Type 2’ fuser life is approximately half that of a standard ‘Type 1’ fuser unit (150,000 pages for a ‘Type 2’ fuser, versus 300,000 pages for a ‘Type 1’ fuser). In addition, the fuser maintenance counter will need to be adjusted so the printer maintenance messages display at 150,000 page intervals.
Brian Ude is a certified printer technician with years of experience. Brian serves Western Office (www.western-office.com) in Billings, Montana. If you have a question for Brian regarding this topic or have any other printer repair related questions or topics you would like more information on, please post a comment on this blog or send an email to firstname.lastname@example.org.