There are two types of fuser for the T65X machines -- type 1 and type 2. A fuser's type is identified by a 'T1' or 'T2' label at the left rear of the fuser's top cover. Here's a view of a type 1.
I looked into this, and found an 'explanation' of sorts, though I remain a bit mystified as to why it was done. The following is verbatim from Lexmark's 4062-XXX Service Manual (pp. 3-73 & 3-74):
"Type 1 fuser unit assembly
In the type 1 fuser unit assembly, the detacs, which are used to prevent the media from sticking to the hot roll, do not make contact with the hot roller. The type 1 fuser unit assembly has a life of 300K.
Type 2 fuser unit assembly
In the type 2 fuser unit assembly, the detacs, which are used to prevent the media from sticking to the hot roll, do make full contact with the hot roller. The type 2 fuser unit assembly has a life of 150K."
I've yet to see a type 2 fuser, but I had a type 1 unit handy, so I took off its top cover to confirm what I'd read in the Service Manual. I inserted a strip of paper from above, and the paper went easily past the detacs, so what the manual says is true -- in the type 1 fuser, the detacs do not contact the hot roller. Here's a view of my test.
I performed the same test on a T640 fuser and on a T630 fuser, and they're all the same in this regard. It appears that with the introduction of the one-piece, torsion-spring sprung detac bar on the T630, the detac fingers were made not to contact the hot roller.
'Detacs' or 'Stripper Fingers'
From what I've observed of fuser operation, the detacs really don't do anything, other than prevent hot roller wrap-around. In a good fuser, the leading edge of a print always comes away from the hot roller on its own; nothing is needed to physically separate the paper's leading edge from the roller. All the detacs actually do is they prevent a print that does happen to stick to the hot roller from wrapping clear around it. A jam still ensues whenever a print's leading edge gets as far as the detacs. The detacs do not serve to neatly peel the leading edge of a print off the hot roller, and cause it to exit without jamming.
I looked into this, and found an 'explanation' of sorts, though I remain a bit mystified as to why it was done. The following is verbatim from Lexmark's 4062-XXX Service Manual (pp. 3-73 & 3-74):- - -
"Type 1 fuser unit assembly
In the type 1 fuser unit assembly, the detacs, which are used to prevent the media from sticking to the hot roll, do not make contact with the hot roller. The type 1 fuser unit assembly has a life of 300K.
Type 2 fuser unit assembly
In the type 2 fuser unit assembly, the detacs, which are used to prevent the media from sticking to the hot roll, do make full contact with the hot roller. The type 2 fuser unit assembly has a life of 150K."
- - -
I've yet to see a type 2 fuser, but I had a type 1 unit handy, so I took off its top cover to confirm what I'd read in the Service Manual. I inserted a strip of paper from above, and the paper went easily past the detacs, so what the manual says is true -- in the type 1 fuser, the detacs do not contact the hot roller. Here's a view of my test.
I performed the same test on a T640 fuser and on a T630 fuser, and they're all the same in this regard. It appears that with the introduction of the one-piece, torsion-spring sprung detac bar on the T630, the detac fingers were made not to contact the hot roller.'Detacs' or 'Stripper Fingers'
From what I've observed of fuser operation, the detacs really don't do anything, other than prevent hot roller wrap-around. In a good fuser, the leading edge of a print always comes away from the hot roller on its own; nothing is needed to physically separate the paper's leading edge from the roller. All the detacs actually do is they prevent a print that does happen to stick to the hot roller from wrapping clear around it. A jam still ensues whenever a print's leading edge gets as far as the detacs. The detacs do not serve to neatly peel the leading edge of a print off the hot roller, and cause it to exit without jamming.
- - -
Part Numbers and Pricing and Compatibility and What the Bleep is This All About Anyway?
The 300K type 1 fuser is P/N 40X4418. The 150K type 2 fuser is P/N 40X5854. The price is the same for either.
I've seen a note on a logistics database that says that the type 2 fuser is for 'heavy media'. I have no idea what to make of that.
In any event, there is no 'compatibility' issue involved. For all practical purposes, there is no 'fit, form or function' difference between the two fuser types.
As I mentioned earlier, I've yet to see a type 2 fuser. If I ever do and I learn more, I'll update this post accordingly.
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Hi Tom Gaspick, Good post on the topic of printer fuser service. Printers are totally different from computers and it is a different service altogether. We are a hp printer service centers in Chennai and must say that poss like these are very useful to our service team.
ReplyDeleteI've just pulled a type 2 Fuser from a T652 that keeps jamming paper. Those "dtac" things have scraped the film off the hot roller. Replacing with a type 1. Thanks for your insights.
ReplyDelete