Before laser printers, printers were usually more mechanical, especially
in putting the image on paper. They did this character-at-a-time, like
a Teletyper, or line-at-a-time, in a very big machine. No page-at-a-time.
Of course, paper feed may well remain mechanical forever.
Here are case histories of line printers that had problems independent of
the degree of productivity with which they were manufactured -- told here
to remind that design and productivity are interlinked, and in that order.
Paper Length I
In the late '60s GE purchased a computer printer manufacturer. I was
among those going to Philadelphia to see what we had gained. Noticing
a physical limit to the length of paper that it could print (11
inches), I asked if they meant to sell outside the United States.
Answer -- a puzzled "yes, of course". But the rest of the world uses ISO
A4 paper, which is 11.69 inches long. There was no way that any foreign
firm would ever buy that printer!
THEY DIDN'T GO TO THE MARKET TO SEE HOW IT WORKED!
Paper Length II
In 1970 General Electric sold its computer business to Honeywell, which
designed its own Page Printing System in 1973. It was roll-fed, not
sheet-fed, the pages being cut to length after printing. Because
Honeywell then had design and manufacturing units in France, Italy, The
Netherlands, and Scotland, it could be confident that international
requirements were met. But the design team worked in some isolation,
perhaps for security against its competitors. Records of previous
design criteria were apparently lost or ignored, for the maximum cutoff
length was again 11 inches.
THEY DIDN'T GO TO THE MARKET TO SEE HOW IT WORKED!
Paper Drive Holes
Most early computer line-printers put output on continuous (fan-fold)
sheets. The driving mechanism was not friction, but rather a series
of perforated holes on each edge of the sheet. This method has by no
means disappeared. The big utilities don't use it, but you'll see it
in a lot of small operations like doctor's office, your garage, etc.
You could tear the pages apart if you wanted or needed to, but quite
often these pages were just archival records. As such, they were put
in binders with spindles at each end to go through the pair of holes
next to the fold line. This process could be tedious, so it should
also be simple.
GE's French affiliate Bull also designed and built a printer, and a
very good one it became. At first, though, the printed lines were
uneven in the vicinity of the paper fold. They showed me their tractor,
or driving mechanism. It was essentially a wheel, with projecting pins,
of which at most two engaged the paper at any time. The paper they were
testing with was quite standard in the United States, in that all holes
adjacent to the fold were enlarged, to put through a spindle of
greater diameter. Naturally, when the two pins were in both large holes,
the paper would slip. They asked me to investigate.
Upon return from France, I called the paper manufacturer, Moore
Business Forms. They confirmed that the larger holes were for spindling
when reports were bound. They said that 98% of the drives in the U. S.
were the Kidder tractor, which they also made. It engaged a large
number of holes simultaneously and never had any registry problems.
The French had to change to a larger number of driving pins.
THEY DIDN'T GO TO THE MARKET TO SEE HOW IT WORKED!
Actually it was worse. They ignored part of my extensive design review.
To do this I first realized that I wasn't much of an expert on hardware
and printers, being a programmer. So I went to the shop floor and asked
for the person most knowledgeable about printers in the real world. Of
him I asked two questions:
- If you had a printer of new design, what changes would you like to
see, and what capabilities would you want that your present printers
do not have?
- What present printer capabilities do you really like, and would
hate to lose?
This got me a huge shopping list, which I passed along. And it helped a
lot. Except for the paper drive problem!
Paper Length III
Honeywell's Page Printing System at first used paper rolls of two
different widths -- 8.5 inches (usually cut at 11 inches), and 11 inches
(usually cut at 8.5 inches for sidewise printing). The printer was what
was called "full matrix", meaning that all characters for a page were
in a chip memory before printing. Different sets of characters could be
chosen.
The rolls were heavy, requiring a special handler dolly. And you had
to use it every time you wanted to print on paper wider or narrower
than the roll currently in place.
I suggested that as this was so, why did they not use the computer to
load the matrix inverted, as on the right in Figure 1?
first line ^ sfftsf <-- "F"
second line | iiohei
third line | paper xfuicr
fourth line | travel ttrros
fifth line | hhtdnt
sixth line | h d
... ll l l
Figure 1.
Then a different character font could be selected, just like the
regular font except turned on the side, like the "F" in Figure 2.
x x x x x x x x x
x x
x x
x x
x
Figure 2.
Now a page could be printed a column at a time instead of a row. Paper
rolls do not have to be exchanged. Always use an 11-inch roll; do not
supply 8.5-inch rolls. An 8.5 x 11 inch page is printed in 8.5 inches
of roll travel, not 11. A speed increase of over 29% is a very good
advantage for market competition.
I got Honeywell to put the idea into the patent application, but it was
ignored in practice from 1974 to 1981!
THEY DIDN'T GO TO THE MARKET TO SEE HOW IT WORKED!
BY CONTRAST, A SUCCESSFUL PRINTER
In the "From the Editor" box accompanying the paper by Borelli,
Bayless, and Truax -- "A Non-Impact Page Printing System",
67-80, Honeywell Computer J. 8, No. 2, 1974 -- I wrote:
"Twenty-four years is an above-average time to wait for a dream
to come true. Since my crude plan for a printer while at the
RAND Corporation in 1950 (paper in continuous roll, with a matrix
of wires embedded in a plastic bar for printing by electrical
discharge), I have always wanted computer output in a form akin
to photographic precesses (rotogravure dots, etc.). Mostly this
was to be able to manipulate, by computer, all of the world's
graphic symbols and characters, and then be able to output them
in visual form."
COMMENT: In contrast to the length limitations common to
the above stories, this printer can/could produce sheet lengths
up to 355.6 mm (which just happens to be the common 14-inch
length of legal size paper).
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