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From: dplatt@coherent.com (Dave Platt)
Newsgroups: comp.sys.mac
Subject: Re: DeskJet questions.
Message-ID: <24707@coherent.com>
Date: 9 May 89 05:02:15 GMT
References: <18465@vax5.CIT.CORNELL.EDU> <126900010@p.cs.uiuc.edu>
Reply-To: dplatt@coherent.com (Dave Platt)
Organization: Coherent Thought Inc., Palo Alto CA
Lines: 51

In article <126900010@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
> 
> (2) Has anyone used this printer with a Mac II?  Does it go faster?
> Did the Mac II have more than 1Mb of memory?

I use a DeskJet with my Mac II (5 Megs, usually running under
MultiFinder).  I use version 2.0 of the DataPak Software driver, with a
few little hacks of my own.

When printing Mac screen-fonts at 300 DPI, the print speed is limited
primarily by the printer's own processor.  The printer cannot keep up
with the Mac, when the printer is swallowing compressed graphics (mode 1
compression) at 19.2 kbits/second.  I stuck an RS-232 line monitor on
the serial line, and saw that the line was spending about 30% of its
time idle with the "Clear to Send" signal deasserted... the printer's
buffer was full.

My understanding is that the DeskJet Plus can keep up with the 19.2
kbit/second serial port under these conditions... the printing speed is
limited by the serial port transfer rate, and not by the printer.  Using
a parallel interface will increase the speed quite a bit, if the Mac can
keep up... the data transfer is faster, and the printer uses DMA rather
than port-polling.

> (3) I heard it costs nearly 10c a page to print, when you figure in
> paper costs, and the expensive ink cartridges.  Is this still true
> with the Deskjet+?

I calculated my costs at under $.03/page for ink... this assumes a
conservative lifetime of 500 pages per cartridge (on the low end; I'm
actually getting about 800)) and a cartridge cost of $15 (quantity-6
price by mail).  Figure $.02/page for paper if you buy at The Price Club
or a similar discount-store.

Your mileage may vary... if you print pages filled with solid black
areas (pie charts, bar charts, bitmapped graphics, etc.) then you may
get only a few hundred pages per cartridge.

DeskJet printing-costs per page are higher than those for a LaserWriter
or LaserJet, due mostly to the higher ink costs.  I figured the
break-even point for the DeskJet/LaserJet comparison at about 30,000
pages... more than that, and the lower per-page costs for a LaserJet
make up for the higher purchase price.  This figure assumes "normal"
use of the printer... letter-quality text, and a limited amount of
graphics.

-- 
Dave Platt    FIDONET:  Dave Platt on 1:204/444        VOICE: (415) 493-8805
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