Printer help?

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Sep 9 20:39:27 2004

>
> ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:
>
> > It worked. It still works. Pity I can no longer get toner for it (I am
> > going to have to work out how to refill those cartridges, and what to
> > use).
>
> Something I've been wondering about too. But what about other parts of
> the EP cartridge besides the toner, i.e., the photosensitive drum?
> Doesn't it also have a relatively short life, a little longer than the
> toner supply but not by much?

I think it will last sevreal times the life of the toner in a cartridge.
So you might be able ot re-load 3 or 4 times (which would at least keep
my PERQ printing a little longer).

Dunno what I'll do after that. I suspect (but haven't tried it) that an
SX-VDO would work, but those are pretty rare. The VDO printers don't have
a formatter board, the external connector (a DC37 socket) connectects to
the DC conrtroller (via a little buffer board in the SX) and the host
machine controls the laser, etc directly.

>
> > Thing about mechanical problems is that you can often observe the unit in
> > opeeration and see what doesn't move when it should (or does move when it
> > shouldn't).
>
> The problem is that the observed symptoms still don't translate into
> a fix. Prior to replacing the job offset assembly on my NX, it had
> the following problem when printing to the main output bin: the paper
> would feed through perfectly fine, but just as it was beginning to emerge
> from the last rollers, it would stop and the front panel would indicate
> a jam. The paper was not jammed, and if pulled out manually the printout

A jam, of course, simply means that the paper sensors didn't trip at the
right times. A particularly nasty-to-trace 'jam' is when one of the paper
tray detection switches fails and the printer thinks it's got shorter
paper than it has. Of course it then thinks every sheet has jammed...

> was perfect. Obviously it was simply moving a bit too slow, and the DC
> controller had very little margin in the number of clock cycles allotted
> for the sheet to clear each sensor, causing it to barf. This much was
> clear. The problem is, how does one go about fixing it? There was no
> component I could directly lay the blame on.

Are there any driven rollers in the is assembly? Maybe one was slipping
so the paper wasn't moving fast enough. I would have tried cleaning and
roughing up the rollers a bit -- not a permanent fix, but it might have
shown where the problem was.

> > FWIW, the DEC LN03 (I have one, I think mine is the Postscript model) is not
> > a Canon engine...
>
> I suspected that it was one of the rare exceptions, thanks for the

It's a strange machine -- I think it's a Ricoh engine. The 'drum' is
actually a photosensitive belt.... I've also seen another non-Cannon
engine, I can't remember who made it. That one did use a drum, but it was
totally different to Canon (sepearate toner and drum modules, for
example).

> confirmation. BTW, am I correct in that LN03R is a pure PostScript
> printer, i.e., PS ONLY and cannot work like a plain LN03? This would

I beleive so. As you mentioned in an earlier message, some Apple printers
are pure postscript (well, there is a Diablo 630 emulation mode, but you
get it by DIP switches, so it's not exactly practical). I have an Apple
LW2NT on this PC (works great, I've got a little filter which came with
my linux distribution to turn text into postscript...)

> make the LN03R quite different from the later LNs, and that is why
> I've long felt that only the original LN03 is the real thing and that

You have almost convinced me to dig out the LN03 sometime and investigate
it...

> the later LNs pale in comparison. And the later LNs are based on a
> Canon engine, and I seem to recall a low-end cheapo one at that...
> Don't remember what ?X, but I seem to recall it's the same one as in
> "Personal" LaserJets and LaserWriters.

LX? If so, it's a horrible bit of machinery :-(


>
> > Are the scanners the same? Normally the higher resolution scanner needs
> > to rotate faster (so as to put more lines down in the same time). I know
> > that on the CX engine there was a 415 (!) dpi version and a crystal on
> > the sannner motor PCB [1] needs to be changed.
>
> I thought the same, and the part swapper guide gives different part #s
> for the IIISi and 4Si Laser/Scanner assemblies. However, a guy here in
> San Diego who professionally repairs these printers told me that he had
> swapped all kinds of parts between IIISi and 4Si that you are not
> officially supposed to swap and it worked; only the formatter and the
> DC controller are different he claimed. Maybe the scanner assembly has
> some kind of switch or jumper inside?

Maybe the speed is actually controlled by the DC controller board (this
is the case on the SX) and the 4SI scanner is designed to run at the
higher speed (but will also work at the IIISi speed). And maybe some
IIISi scanenrs will go at the faster speed too (a bit like SS .vs. DS
floppies :-)). Not having got one of these printers I can't comment any
further.

-tony
Received on Thu Sep 09 2004 - 20:39:27 BST