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From: neff@hpvcla.HP.COM (Dave Neff)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Addendum to my "review" of the HP Desk Jet printer
Message-ID: <4740014@hpvcla.HP.COM>
Date: 23 May 88 18:19:14 GMT
References: <1184@neoucom.UUCP>
Organization: Hewlett Packard, Vancouver, WA
Lines: 53

I worked on the DeskJet Epson Emulation cartridge and Landscape cartridge 
firmware so I could answer a couple points raised.

We absolutely did eliminate any PCL level IV features that would require
a page formatter or backing up the paper.  The poster is quite right that
we cannot backup without smearing ink and adding the additional RAM would
make our price closer to the low end laser printers.  One key advantage
the DeskJet technology has over laser printers is the ability to do a page
of 300DPI graphics without adding large amounts of RAM.  Of course a page
of RAM gives other capabilities (area fill, page formatting, etc.) that
we also forfeit.  We could have added macros and cursor pushes or pops
without much problem.  We didn't think people would use these features
on a non page formatting printer.  Were we wrong?

Yes, the printer has a Z80 running at 4MHZ with a proprietary IC that
handles much of the misc. logic, paper and head movement, and uses
DMA transfers to move text commands and graphics data from the internal
RAM into the print head.  If you are really interested in all the gory details
a future HP Journal issue will contain numerous articles about the
printer.  It will be the October issue I think.  Be sure to read
the article about the Epson Emulation cartrige :-)

As for the download format, one of the reasons we do not support
LaserJet soft or hard fonts is due to the fact our fonts are tuned
for the inkjet technology.  In fact, fonts are designed on a 600x300
dpi grid.  We can actually print at 600 dpi horizontally, but at
that resolution we can't print consecutive dots.  By designing fonts
on the 600dpi horizontal resolution we get significantly better
print quality than using straight LaserJet fonts.  By the way, the
DeskJet fonts are modifications of the LaserJet fonts.  Also remember
LaserJet fonts are about 3 times as expensive ad DeskJet fonts so
you wouldn't want us to force people to buy the LaserJet fonts would
you?  Of course if you already have LaserJet soft or hard fonts it
would be nice if they worked in the DeskJet, but sorry they don't.

The download format is not proprietary and we are giving it out
to independant software vendors upon request.  If you are writing an
application that would like to exploit our download capabilities
give our support line a call (I don't have the number sorry).  If
you are just curious, you may have trouble getting the info from
them.  Eventually we will make the download format universally
known, but for now we are trying to have some control over that
knowledge for marketting reasons.  I probably can't say more and
probably have said too much.  I guess for now you could say
we are considering the format to be "semi" proprietary.

If anyone wants specific answers to questions about the DeskJet
don't hesitate to write.  If you have suggestions for future
printers using the DeskJet technology I would love to hear from
you.

Dave Neff
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