Buying a a new printer

[Softus]

The problem with printing onto the second side of used prints is contamination of the feed rolls more than the fuser, copiers designed for d/s copying usually have a separate tray that side one is fed into inverted, so that the rollers drive on a clean sheet of paper & do not get contaminated by toner from the first.

Copiers do indeed have a separate tray, but your claim about the feed rollers is just same made up b*llocks.

As you say they pass through the same fusing process for the second side as the first

That's not what I said. It's also not what happens. The used paper, when being copied onto the reverse side, passes through the same change/transfer/detack cycle, before even reaching the fuser.

so that will not be a problem, in any case the fuser roll is usually of a smaller diameter than the length of the paper so they have to have an efficient cleaning system built in.

The length of a sheet of A4 paper is 210mm. For a roller not to encounter the same sheet more than once, its diameter would have to be approximately 7cm. Clearly no copier or printer has a roller this size.

Your words are increasingly appearing to be utter tosh, and your knowledge seems far too sketchy to use as a basis for giving others advise.

 

[Inky Pete]

Duplex capable laser printers use polyester based toners which are designed for passing through the fusing process twice. They also often have oiled fuser rolls to prevent toner sticking to them. Some of them even temperature switch so that the hot roll is 20 or so degrees hotter when fusing side one than it is when fusing side two.

The problem I was pointing out is that in reusing paper which has been printed on elsewhere, you can't know whether the original toner has a melting point higher or lower than the temperature of the fuser in your home machine.

 

[Softus]

Duplex capable laser printers use polyester based toners which are designed for passing through the fusing process twice.

Er, do you know of any xerographic copiers or printers that don't use poylester-bound toner?!

The problem I was pointing out is that in reusing paper which has been printed on elsewhere, you can't know whether the original toner has a melting point higher or lower than the temperature of the fuser in your home machine.

A very valid point, especially when that original 'toner' might be inkjet ink.

 

[jj4091]

The problem with printing onto the second side of used prints is contamination of the feed rolls more than the fuser, copiers designed for d/s copying usually have a separate tray that side one is fed into inverted, so that the rollers drive on a clean sheet of paper & do not get contaminated by toner from the first.

Copiers do indeed have a separate tray, but your claim about the feed rollers is just same made up b*llocks.

As you say they pass through the same fusing process for the second side as the first

That's not what I said. It's also not what happens. The used paper, when being copied onto the reverse side, passes through the same change/transfer/detack cycle, before even reaching the fuser.

so that will not be a problem, in any case the fuser roll is usually of a smaller diameter than the length of the paper so they have to have an efficient cleaning system built in.

The length of a sheet of A4 paper is 210mm. For a roller not to encounter the same sheet more than once, its diameter would have to be approximately 7cm. Clearly no copier or printer has a roller this size.

Your words are increasingly appearing to be utter tosh, and your knowledge seems far too sketchy to use as a basis for giving others advise.

What the hell's your problem, as far as the fuser was concerned I was completly agreeing with you, the feed roll isue is completely valid, as when the rollers rub against the toner on the first side they pick up a residue onto the rubber which forms a film leading to mis-feeds, it is impossible to fuse all the toner completely 100% into a sheet of paper. As far as my experience of copiers is concerned I am willing to bet I have repaired more of them in my career than you have seen in your life unless you have more than 30 years in the industry(I was around long before detack corotrons came along, they used to rely on a metal stripper finger).

 

[Softus]

What the hell's your problem, as far as the fuser was concerned I was completly agreeing with youp

You couldn't possibly have been agreeing with me, because all I'd done was to ask you how you thought the xerographic process worked.

the feed roll isue is completely valid, as when the rollers rub against the toner on the first side they pick up a residue onto the rubber which forms a film leading to mis-feeds, it is impossible to fuse all the toner completely 100% into a sheet of paper.

You implied that duplex copiers are designed in such a way as to avoid contaminating any feed rollers. This is factually wrong.

As far as my experience of copiers is concerned I am willing to bet I have repaired more of them in my career than you have seen in your life unless you have more than 30 years in the industry.

I'm not a gambling man, so I'll leave you to do the betting. FYI, I used to work at Rank Xerox (and Xerox), in R&D, principally formulating toner and carrier, and I doubt very much that you've repaired more than I've seen.

What I'm certain about is that whatever knowledge you do have, you're incapable of putting it across accurately.

 

[jj4091]

I spent 30 years at xerox & I seem to recall that if the paper was fed from a second tray it would be rather difficult to contaminate anything in the first one, I was not saying they were designed that way to avoid this,merely that it was a consequence,as opposed to refeeding a copy in a machine that inverts(turns the paperover) from the feed to the transfer.As far as my knowledge of the Xerogrphic process is concerned I suspect that it comes below Chester Carlson's, but way above yours. I hardly think experience of R&D in toner gives you any knowledge of the problems experienced in the field, but then it was always apparent that there were a lot of halfwits in Mitcheldean or which ever ivory tower you worked in. Like you I was not trying to advise anyone on what sort of printer to buy only to add to the drawbacks of using them in certain ways.

 

[Softus]

I hardly think

I know.

 

[Inky Pete]

Duplex capable laser printers use polyester based toners which are designed for passing through the fusing process twice.

Er, do you know of any xerographic copiers or printers that don't use poylester-bound toner?

Yes, many of the older large production lasers (1000 pages per minute and above) in use for bulk printing by the banks, utility companies and junk mailers are still using carbon black based toners. These toners don't penetrate the paper fibres as well as the newer polyester ones when fused and typically lead to a greater "pile height" of toner on the page. The print will look slightly shiny black and can feel raised on the page, especially on glossy coated papers. This stuff remelts and comes off all over the place when it's reheated.

There are even one or two of the really old "cold fuse" machines still in use which fuse the toner to the page by exposing it to a bath of a gaseous fusing agent which causes a chemical reaction. Then there are the "flash fuse" machines which use a high intensity lamp like an enormous flash gun to cure the toner. I've absolutely no idea how these sorts of toner would react to being exposed to the heat and pressure of a conventional fuser!!

 

[tim west]

I used to work at Rank Xerox (and Xerox), in R&D, principally formulating toner and carrier, and I doubt very much that you've repaired more than I've seen. .

You told me you were a fishmonger!