On 07/13/2017 08:39 PM, Tony wrote:

If I print in duplex mode, I get a dirty mark across the page on the
second side. It's the same whether I print from the tray or from the
manual feed.

Could this be a cartridge problem? It's a years-old remanufactured
cartridge, but the dirty marks have only just appeared.

Reliable cartridges now seem to be somewhat scarce and expensive. Would
it be more economical in the long run just to buy a new printer with
cheaper cartridges? Brother? Samsung?

It sounds like the dirty marks are coming from the mechanism that turns
the page over for duplex printing. Chances are you can clean the
printer and eliminate the problem. But if the dirty mark returns, it
might be caused by toner leaking from a worn-out cartridge.

I have had good luck with both HP and Brother. Not familiar with
Samsung.

NOTE: Smaller cartridges are usually more expensive per page printed.

Sorry, Fred, I only just saw your reply. In the meantime I bought a new
(remanufactured) cartridge, which certainly produces blacker copies but
does not eliminate the smudge, so I think you are right about the
problem being in the duplexer mechanism. Now to figure out how to get at
it.

I did look at Brother laser printers but found that the cartridges are
not as cheap as I had imagined.

Getting at the roller that is involved in duplex printing seems to
require major disassembly of the printer. Are there laser-printer
cleaning sheets that will work with a duplex printer? I have some sheets
that consist of very thick and stiff paper with some somewhat sticky
bands on one side, but they get jammed if I try duplex printing.

Perce
I am not aware of any cleaning paper of that sort, but as a word of caution be
very careful to not use any coated paper in laser printers unless it is
specifically stated as being suitable for laser printers or photocopiers. To do
so risks damage to the fuser.

It's the same stuff I used for the LaserJet III (which was not a duplex
printer, of course) many years back, and it claims to be specifically
for laser printers, copiers, and FAX machines.

Let me give a more detailed description of the problem:

Double-sided 8.5" x 14.0" prints have a grayish line the full width of
the page (but not uniform density across the page) on the second side a
couple of inches from the end "outer" end, i.e., the end that entered
the printer last. Double-sided 8.5" x 11.0" prints have the same line,
but a little closer to the end of the page.

As far as I can see the only full-width rollers are the black one that
is visible when the toner cartridge is removed, and a reddish-brown one
that is visible when I open the back to allow paper to collect at the
back -- but then there is no duplex print capability. That latter roller
looks perfectly clean to me but is not easily accessible.

Perce