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From: stever@videovax.UUCP
Newsgroups: comp.sys.amiga
Subject: Moronic printer drivers
Message-ID: <4175@videovax.Tek.COM>
Date: Thu, 22-Jan-87 12:47:22 EST
Article-I.D.: videovax.4175
Posted: Thu Jan 22 12:47:22 1987
Date-Received: Sat, 24-Jan-87 09:45:49 EST
Reply-To: stever@videovax.Tek.COM (Steven E. Rice, P.E.)
Organization: Tektronix Television Systems, Beaverton, Oregon
Lines: 62
Keywords: slow, slower, slowest
Summary: Aaaaarrrrrrgggggghhhhhhh........

We have an Epson JX-80 (color) printer, which produces quite acceptable
output.  (As an example of the things we do with it, last night my older
son made a very fancy birthday card for a friend, using DPrint.  My wife
also prints her homework, in black-and-white.)

There is one fly in the ointment, though.  When we have selected "JX-80"
in Preferences, the output is agonizingly slow!!!  On each line, the
printer driver insists on printing the full width of the paper for each
color, even if nothing is to be printed on that line!  Of course, the
printer has to cycle the (multistripe) ribbon up and down with each
color, so it takes five to ten seconds per line.

When the output is only a line feed, the printer driver still cycles the
ribbon through all four colors before moving to the next line.  We can
get around the problem by selecting "FX-80" in Preferences, which
produces fast black-and-white output, but this renders color printing
unavailable.

There is a solution -- the JX-80 printer driver needs to optimize
printing for best throughput.  Some suggestions (in the comments
below, "line" means the vertical expanse that can be printed in a
single pass of the printhead):

  1. Neither printhead motion nor ribbon motion should occur unless
     there are one or more dots to be printed on a given line.  If a
     line consists entirely of empty pixels, (even hundreds of them),
     all that is required is a line feed.

  2. The ribbon should not be cycled to a color that is not used on
     the line being printed, nor should any printhead motion occur
     for that color.  Ribbon motion is one of the slowest functions
     on the printer, so elimination of unnecessary ribbon color changes
     should have a very high priority.
     
  3. The printhead should go only as far as is required to print the
     last active dot for each color on the line.  Why waste time
     sweeping across 8-1/2 inches of paper and returning across the
     same 8-1/2 inches when the only dots to be printed are within
     one inch of the left edge of the paper?

  4. The rest state of the ribbon should be on the black stripe,
     so it will not be necessary to move the ribbon at all for
     black-and-white printing.

  5. If there is only black-and-white information to be printed, do
     not send any ribbon motion commands (not even "go to black ribbon").
     Combined with (2) and (4), above, this will permit black-and-white
     printing as fast as if "FX-80" had been selected in Preferences.


All-in-all, these improvements would probably double the printing
speed for sparsely-colored images, and increase the speed for
black-and-white printing by ten times.

How about it, Commodore-Amiga?  Can we hope for an improved JX-80
printer driver in V1.2?  Or can I get the source for the JX-80 printer
driver so I can hack these changes in myself?

					Steve Rice

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