Print Quality Issues – Middle of Page – HP Laserjet 4240, 4250, 4350

 

Print Quality Issues – Middle of Page – HP Laserjet 4240, 4250, 4350

Print quality issues in the middle of the page have always been an issue with hot rollers. This problem went away briefly with the invent of the fusing fixing film. However, with the increase speeds and the problems with the HP 4200 series, metal had to be added back in to make the units more durable. With metal back in the fuser  the ghosting, repeat image, or smudging  problems are back in the HP laserjet  4240, 4250, and 4350 fusers. In this article I will discuss what causes print quality issues in the middle of the page on these machines, how to troubleshoot them, and how to replace the fusing assembly if needed.

Print Quality Issues – History of Ghost Print and Smudging in the Middle of Page

HP 4200 laerjet printerBack in the day and on larger model machines, HP’s had an  upper hot roller in the fusing assembly  that was made out of metal with a coating covering the surface  . These units  had a lamp or lamps running through the middle of the hot roller that heated the fuser  up to its correct operating temperature. Several manufactures still use this method but HP has drifted away from this design. Now  most HP’s  use a heating element surrounded by a circular fixing film. While the fixing film has its own sets of problems it has allowed for faster first prints out. In early models like the 4200 series if the edges of the film got a little nick in it or if something like a staple was fed through the fuser  it would create a small tear. At first the tear wouldn’t really affect anything. Over time though the tear would snag on something else and eventually rip a section of the film off, creating a large void resulting in extreme  print quality issues  and constant paper jams.

Starting in the HP laserjet  4240, 4250, and 4350 printers HP inserted a metal coating inside the fixing film to prevent tears and make them last longer, noticeable  by the higher page count between PM cycles. What I’ve seen in the past and in the last few weeks is the  outer coating of the fixing film wearing away in the middle, exposing the metal beneath. Once the metal is exposed toner doesn’t properly bond to the paper and print quality issues arise like ghost print and/or  smudging.  Most times I see this happen between 150,00 and the 225,000 PM cycle. On a lot of machines I don’t see this problem. Majority of the times I see print quality issues like this are machines that are 5 years old and never have had the fuser  changed or printers where the customer runs third party  or refurbished toners in the unit.

Refurbished Toner Cartridges Can Cause Print Quality Issues on the HP Laserjet 4240, 4250, and 4350 Printers

One thing with non OEM cartridges is the toner used in them. Toner under a microscope looks like grains of sand. The smaller the toner particle the higher the DPI and the more expensive the toner. In order to cut cost lots of companies use a larger grain. Because most customers only print text they never really notice the difference. The problem is toner is kind of like sand paper. The larger the grain the more coarse  it is. So refurbished toner cartridges using a cheap, larger, toner particle wear more on the fuser  than OEM toner resulting in premature break down of the outer coating on the fixing film. One of our former employees works as an IT person for one of our accounts. Since this company has grown to international levels they have cut back on cost by using third-party toners. He has noticed since that time they are going through fusing assemblies a lot more than in the past. Not because they are hitting their PM cycles more often but because the outer coating is wearing away resulting in print quality issues.

Troubleshooting Print Quality Issues in the middle of the Page on HP Laserjet 4240, 4250, and 4350  Printers

I use to say just do a half test. Really though the fuser  is so easy to take out and check I would probably just recommend doing that. Remove the fuser  by following the instructions below. Open up the back exit section and check the fuser  film coating. If the coating is worn away it will be pretty obvious. If everything looks fine then try a half test. Print a test page that has full coverage like the config  page and stop it half way through the machine. Open the top cover remove the toner and check the partially printed page. If under the toner you already see print quality issues then replace the toner. If you don’t see an issues then open up the back door and print another page. As you see the leading edge start out the back open the lid and check again. The paper should be stuck in the middle of the fuser. If the bottom half and the page looks fine but the top half shows signs of ghost print or smudging then most likely the fuser  will have to be replaced. Usually   it’s pretty obvious when the fuser  is at fault for this print quality issue because of the coating being worn away but that doesn’t always have to be the case. Like I tell all my customers who want troubleshooting tips. Always replace the cartridge first for print quality issues,  especially if they are using third-party cartridges. If that still doesn’t work or they really want to see me then I’ll come out and take a look at it. But it might save them a few bucks if they take my advice first.

 

HP 4240, 4250, 4350 Laserjet  Fuser Removal
Note: Unplug power and communication cables and allow at least 10 minutes for cool down before fuser removal.
1. Open the rear output bin. Use your finger to squeeze the hinge pin (formatter side) out of its mounting hole.
2. Rotate the output bin away from the printer until the right hinge pin is released, and then remove the output bin.
3. Squeeze the blue fuser release tabs
4. Pull the fuser straight back and out of the printer.

Conclusion about Print Quality Issues in the Middle of the Page on the HP laserjet 4240, 4250, and 4350 Printers

Obviously print quality issues like ghost print and smudging are not always fuser related issues. Hopefully after reading this article you have a better understanding of what to look for a better isolate the problem so you don’t spend money on parts you might not need.

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For More information involving Printer Repair and some articles I have written check out: http://blog.marketpoint.com/

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