24 Jun
2015
24 Jun
'15
9:33 a.m.
On Tuesday, June 23, 2015 at 22:14, jwsmobile wrote:
Also I don't recall the Data Products ever scaling
as fast by
restricting columns. At least our 2230, 2260 and 2290 UC only and 96
character set printers didn't. Got the same speed regardless of the
columns on those Data Products printers.
The HP 2767A service manual (02767-90002, available from Bitsavers) is a
reprint of the Data Products 2310 service manual. Page 1-17 says:
"The printer receives data from the user system and stores up to 20
characters in the buffer memory. [...] A full line of data is
printed in four zones, each zone having 20 consecutive print
positions. In this manner, the printer's 20 hammer drivers can be
time-shared among the 80 print positions."
...and the spec on page 1-5 says the print rate for the 64-character drum
is 356 lines per minute for 80 columns, 460 lpm for 60 columns, 650 lpm for
40 columns, and 1110 lpm for 20 columns.
I tested a 2767A as a customer of the HP Rockville, MD office in the early
1970s. As I recall, the character set wasn't staggered on the drum, and
the hammer force was constant, regardless of glyph area. The result of
printing a line of hyphens -- or worse, a line of periods -- was a very
loud bang and a neatly perfed page.
-- Dave