[Samba] Print speed with an HP Laserjet 4

[Mike Brodbelt]

Kurt Pfeifle wrote:
> Mike Brodbelt wrote

>>This printer is set up with the HP LaserJet 4 driver for Windows NT 4
>>that came on the NT 4 installation CD. When the print job is redirected
>>to a file, I get a PCL file that is 14830 bytes in size.
> 
> So this is the result for the native Windows PCL driver.
> 
>>The networked LaserJet 4 printers were using a newer driver, downloaded
>>from the HP website. This generates a PCL file that is 2392464 bytes in
>>size for exactly the same document.
> 
> I am not clear if this also was a native Windows driver? And if it
> had some weird settings ("print as graphic" or similar)?

Yes, this is also a native Windows driver, downloaded from the HP site.
It provides a couple of different options from the one that shipped with
NT, but nothing major. There is an "NT Forms" tab, andd a "Configure"
tab that are driver provided. I've been through all the options, but
can't see anything that explains the enormous bloat.

Comparing the two PCL files directly, the small one contains PJL start
and end codes, which encapsulate the text of the document and some PCL
codes. The large file has PJL start and end codes (but somewhat
different ones), and the rest is all binary. It's sent the data as
graphics, or embedded the fonts, or something, but I can't see any user
visible interface elements in the driver setup that might control this
behaviour. The output has options for 300 and 600dpi (defaults to 600),
and also for sending TrueType as bitmap (defaults to off), but I haven't
yet tested combinations of settings.

>>The new setup, uses the PostScript driver. Ghostscript is invoked to
>>render this into PCL suitable for sending to the printer. I tested the
>>PCL output by manually generating it:-
>>
>>cat pstest.prn | /usr/bin/gs -dSAFER -dPARANOIDSAFER -dBATCH -dNOPAUSE
>>-q -sOutputFile=test_gs.pcl -sDEVICE=ljet4 -
> 
> 
> So this looks like the ljet4 driver compiled into Ghostscript....

Yes indeed.

>>As I need to leave the billing system in place, I still need to use the
>>PostScript drivers on the Samba server. The bottleneck appears to be the
>>time to send the job across the network to the printer, and the time the
>>printer itself takes to process the PCL it receives.
> 
> 
> You are not mentioning the time it takes for Ghostscript to convert
> the incoming PostScript to the PCL raster....

Running the above command line on the machine doing the conversion, a
bit less than 2 seconds.

> Have you printed this "to file" and then sent it as "raw" to the printer?
> (Oh, I seem to remember, that this was your initial experiment...)

Yes, that's the 900k file. Faster than the 2Mb PCL file, though not as
fast as the PCL driver from the NT CD.

>>It would seem that
>>the best way to optimise the printing process would be to reduce the
>>size of the final PCL file. Is there any way of having ghostscript
>>optimise the resultant PCL output for size?
> 
> 
> It *may* help trying another driver.
> 
> Which is the "driver" you are using on the Linux side of things? Still
> ljet4?

Yes.

> What is the output of
> 
>    head /etc/cups/ppd/[printername].ppd ?
> 
> (This would show me which filter/driver you use.)

Not using CUPS at the moment - the Linux side spooler is LPRng. I'm
looking at CUPS with growing interest, and setting up a CUPS test
install is on my list, but I have a working setup with LPRng, and don't
have the time to change it at the moment. Printbill doesn't yet support
CUPS, though that's starting to change. I suspect I'll switch over to
CUPS in due course, but I think it's a few months away yet.

> Also, have you checked for our latest recommendations of drivers
> at Linuxprinting.org?
> 
>     http://www.linuxprinting.org/show_printer.cgi?recnum=HP-LaserJet_4_Plus
> 
> (I can't remember what your printer models are. But there are more
> than one driver to use with laserjets. You can choose between the native
> CUPS builtin driver (used by laserjet.ppd, not listed on linuxprinting.org),
> ljet4, hpijs, and gimpprint. ljet4 is recommended. Please test and tell
> us if we should recommend another one.

>From a preliminary look, the ljet4 driver generates the smallest file
from my postscript, though this is still more than quadruple the size
of the postscript file, and approximately 65 times the size of the PCL
generated by the driver that originally shipped with Windows NT 4. To
compare like with like I suppose I should test with Postscript generated
by the Laserjet 4M driver that shipped with NT4. I'll do that in due
course, and post results.

Thanks for the help so far,

Mike.