Were Diablo printers noticeably better than Qume?

[BlueHawk]

Hi all – I just read through this fascinating interview of some of lead engineers for Xerox Diablo daisy wheel printers: https://archive.computerhistory.org/resources/access/text/2017/03/102738203-05-01-acc.pdf

They describe the clean sheet approach they took to redesigning their print wheels, replacing those supplied by a Swiss supplier (Charactêres). It sounds amazing, like they dramatically improved the quality and durability of the print wheels (while also hugely reducing their cost).

Do you remember if Diablo had noticeably better print quality than Qume, NEC, Brother, Juki, et al? I'm thinking of the 630 in particular, since they say it incorporated all their advances and the new wheels. I've been thinking about buying a 630.

Thanks

 

[Chuck(G)]

Shoot, I've given away Diablo 630s. Are they suddenly valuable now? Even after laser printers, a lot of insurance people used them because of the multi-part forms.

At any rate, it's worth acknowledging that a lot of Diablo engineering talent did move to Qume after the Xerox buyout. I always thought that Diablos were better-constructed than Qumes or NECs for that matter. Wang used Diablos and they were used by a number of early word processor manufacturers. Diablo also made special-purpose multi-head printers as well.

 

[Slob]

I worked for a company that used HyType II subsystems, and then went to Qume, after designing a look-alike case for it out of the plastic foam that computer equipment like terminals were made of at the time. I had to repair both types.

Pluses of Qume's:

Likely cheaper
Lighter
Simpler printhead replacement
Power transistors easier/cheaper to replace
Picofuses on the transistors (also a minus..)
Microprocessor based (F8?)

Minuses of Qume's

Mechanically less sturdy
Optical printhead motor feedback, did NOT like dirty/smoky environments, incredibly delicate graticule almost impossible to clean in field, very expensive to replace
Somewhat flimsy PCB's and card cage (sheet metal)


Pluses of HyType II's
Sturdier Mechanically/PCB's (cast frame/card cage)
electromagnetic feedback printhead motor, very dirt/cigarette smoke resistant
Very detailed service manual

Minuses of HyType II's
Heavy
No microprocessor, custom TTL processor
Difficult to fix boards (some)
Probably more expensive

I have some interesting repair stories on both...I wish that I would have picked up one when they were common and cheap at the beginning of the laser era.

 

[Chuck(G)]

Used to have the original HiType on my S100 box. OEM (12-bit) interface. Said printer had a very noisy external power supply with three fans in it. Since the printer was essentially a dumb peripheral, I had to work out the driver to dot spacing and direction in a driver--still have the code somewhere. At Durango, we had a Diablo dot-matrix printer that someone had probably taken home as a production prototype. Unbelievably noisy; like the daisywheels, had a carriage servo that could crush your hand if you poked it into the works. I was informed by one of the guys who worked on the firmware that it used threee (!) PPS-4 micros in that funny Rockwell stagger-pin package.
Still have a NEC Spinwriter mouldering away somewhere. I confess that I haven't had the motivation to even power it up.

 

[BlueHawk]

Were these things flawless in printing text? I mean were there smudges, smears, or crooked registration? One of the engineers said that the initial invention had the daisy wheel spinning continuously, non-stop, and when the right character came around the hammer hit it in a fraction of a second. But this had smearing and durability issues, so they came up with a servo deal that stopped the wheel for each strike.

Were Diablos any better than Selectrics and other typewriters? Or too close to call? The early laser printers always seemed subpar to me, with visible dots, not as crisp as they are now, so I'm surprised that people chose laser over daisy wheels so quickly.

 

[Chuck(G)]

A properly-adjusted and maintained HiType produced flawless print, pretty much identical to that of an IBM Wheelwriter typewriter.
I'm not certain about prototype ones, and George Comstock is no longer with us, so he can't say. But drum, train and band line printers used continuously moving type. I've got manuals that were printed on HiTypes and they look pretty darned good. Recall also, that early Selectrics coiuldn't do prop spacing, whereas daisywheels could. One of the reasons that laser printers overtook fixed-font printers was that they could do graphics seamlessly, as well as change fonts automatically--and they printed faster--much faster.

Perhaps there's some first-person stuff in the CHM oral history archives.