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It was a long-awaited event when our Mathematics Department finally
obtained the funding for purchase of a laser printer for support of
departmental TeX use. I wrote the bid specifications for such requests
from both Mathematics and Chemistry here, and from the bid responses,
we chose the Imagen 8/300 laser printer. This was a difficult
decision, because the laser printer market has been rapidly changing.
In the fall of 1983, when I sent out the first bid request for
Chemistry, vendors responded with offers for printers costing $20,000
to $30,000. Rumors of price breakthroughs were beginning to appear in
the trade journals at that time, and Chemistry elected to retract their
initial bid request and wait. Prior to that time, the print engines
used in all of the printers were expensive -- about $7K in OEM
quantities to the vendor, to which had to be added a controller,
documentation, and support to make a marketable product. Resolutions
available were 240, 300, and 480 dots/inch, with printing speeds of 5
to 15 pages/minute.
The market change came from Canon, who introduced their 300 dot/inch
LBP-CX engine, which costs around $1K in OEM quantities. It is worth
noting that Canon's Personal Copier, which uses a similar, but not
identical, engine, is available from discount suppliers for about $550.
Approximately fifteen companies in the USA were licensed by Canon to
build laser printers with this engine.
By virtue of the disposable LBP-CX printer cartridge, the toner supply
and the wear-prone drum surface are discarded after about 3000 copies,
giving noticeably better copy quality over the lifetime of the printer.
The rumored end-user price of about $6K turned out to be overly
optimistic, for Imagen and QMS both announced products based on this
low-cost engine in May, 1984, at around $12K (for engine plus software
for typesetting with TeX, Scribe, and troff). The Hewlett-Packard
LaserJet at $3500 followed in August, providing limited graphics and
daisy-wheel printer emulation with the same print engine. DEC and
several other vendors offered products of similar limited ability later
in the fall, but none offered the typesetting and graphics support that
Imagen and QMS products had.
In late February, 1985, Apple Computer announced their Laser Writer,
which at a list price of just under $7K (and discounted prices under
$5K), has the most powerful graphics and typesetting support ever
offered on a laser printer, thanks to a very powerful controller which
interprets the PostScript page layout language developed by Adobe
Systems. We have ordered a Laser Writer for our DEC-20, and I expect
that a <PLOT79> device driver for it will be available shortly after it
arrives. At the time of writing this in May 1985, neither Imagen nor
QMS have responded to Apple's challenge, although QMS has recently
announced PostScript support, but further price drops are almost
certain. In the meantime, two or three other Japanese companies have
announced low-cost laser printer engines with disposable cartridges,
and products using these should soon be appearing.
This has been a long introduction to my review of the Imagen 8/300, but
I believe the background is important for people who are considering
purchasing a laser printer. The decision between the Imagen and QMS
offerings to the Mathematics Department was close, and decided by
marginal differences in price and software offerings. I have spoken to
several people who have printers from either company, and all seem to
be quite satisfied with them.
Besides fine TeX DVI output and printer spooler support for the Imagen
printers for VAX VMS and VAX Unix, Imagen offers line printer emulator
and daisy wheel support, plus support for Tektronix vector graphics,
and Impress vector graphics and bit-mapped graphics. The printer has
been completely trouble-free, and we have received one upgrade of the
controller software which has removed the ``dead stare'' modes the
printer descended into occasionally. Imagen provided an unsupported
printer driver for use of the 8/300 from the DEC-20 for TeX and Scribe,
and that regrettably has been very troublesome. It was contributed by
another Imagen site a couple of years ago, and is written in a
combination of SAIL, C, and FAIL (assembly language). The sad tale of
getting this running will not be repeated here, but DEC-20's are not
being sold anymore, so the problem will disappear on its own.
The one problem with the 8/300 that should be noted here is that it
does not at present have sufficient internal memory to store a complete
page image, so with vector graphics files, it must store the file
internally and make multiple passes through it, formatting bands of the
plot. The technology of laser printers is such that the drum must turn
at a constant rate or data will be lost, and with even moderately
complex vector plots, such as most of the hidden-line and contour plots
in the <PLOT79> Demonstration Programs, the 8/300 cannot keep up, and
the plots are ruined. In bitmap graphics mode, the vector to raster
conversion is done on the host, and the printer does just fine. The
drawback is that a typical page image takes from 0.5 to 1.5 Mbytes of
data, which means a transmission time at 9600 baud of several minutes,
and the bitmap requires about 90 seconds of CPU time to format on a VAX
750 running VMS. The corresponding vector file usually requires only a
few tens of kilobytes.
Imagen is aware of the problem, and is working on a memory board which
will allow an upgrade to a full page bitmap.