"Jimmy Wilkinson Knife" Wrote in message:
On Sun, 27 May 2018 23:58:20 +0100, Paul wrote:

Jimmy Wilkinson Knife wrote:
On Sun, 27 May 2018 23:21:27 +0100, Paul wrote:

Jimmy Wilkinson Knife wrote:
Why are inkjet printers faster in black than in colour? Surely black is
just one of the inks, like cyan, magenta, and yellow. Since the heads
are independant, why would black only be faster? Is there a ****ty
processor in the printers that's slower than the 4 heads combined?


Time the prints, take the ratio, and see how many
passes are used to do color.

It does seem to move in small jerks then a big one. So is this because
of the processor being slow? Why can all the heads not print at once?
I'm assuming the resolution of each head is the same for the black and
all the colours.

The printer also has a couple modes for level of detail.

See if the color mode supports a preview mode rather than
an "art quality mode". To do photorealistic prints on
coated paper, the printer is likely to move the head slower
while doing that.

It's on standard setting all the time, but speeds up for areas of the page without colour. If I printed a webpage where there were images in one half, then that half would be slower.

I would hope an inkjet doesn't have a processor, because
some inkjets retail for $50, and how much of a processor
can you afford with a retail markup on that ?

It is a $50 inkjet - The Epson S22.

The other printer types, which might have PCL or PostScript
interpreters, they have a bit more of a processor in them.
And to some extent, they were RAM dependent (you could
upgrade by adding memory sticks to them).

Yes I remember those old beasts, the original HP Laserjets.

For an inkjet, to save costs, all you need is a stepper
motor, and a raster scan algo to do the printing. Is
a USB2 30MB/sec data rate sufficient for that ? I hope
so, as scanning manages to work at the 2MB/sec range.
The printing isn't necessarily proportional either.
I should be done with half-tones, with 2 picoliter dots
delivered in a pattern, to give an intensity of color.
I don't think it would be all that easy to modulate
dot volume and get the dot delivered properly.

You *don't* think it would be easy? Why would it be harder to modulate 4 heads than 1 head?

The processor in your desktop, is probably a hundred
times more powerful than the old interpreter processors
that were located inside some of the older printers.
It shouldn't be a strain to produce a raster pattern
from such a processor. You can even look at your percent
CPU while the print is happening, and "see if anything
is railed" during periods of printer hesitation.

Virtually no CPU usage at all.

Whenever processors work with hardware, it is not matter what
processors can do, but what hardware can do.

It is possible the ink technology requires slower printing rate
for colour printing.

For given resolution and ink usage, there is an optimal printing
speed and the firmware is programmed to use it, even if it was
able to print faster.

Many ink printers are sold below their production price, with
the business model based on service, paid by the cartridge
price. 2-3 sets of cartridges have often the cost of the
printer.

--
Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)

"Humour is the only effective weapon against stupidity."
Miloš Forman


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