From: diamond@vulcan1.edsg.hac.com (Warren R. Diamond)
Newsgroups: comp.periphs.printers,comp.os.ms-windows.setup,comp.os.ms-windows.misc
Subject: HP LJ4 paper curl rumors, conspiracies, experiments
Date: 21 Dec 92 23:39:53 GMT
Reply-To: diamond@vulcan1.edsg.hac.com
Followup-To: comp.periphs.printers
Distribution: usa
Organization: Hughes Aircraft Co., EOS, El Segundo CA


Hello,

There has been an ongoing discussion on how the new HP LJ4 printer produces
output that has an excessive paper curl.  The curl is usually described
as a good bend near the top of the page, followed by 2-3 body waves.

Having recently purchased an HP LJ4 printer, and having been listening
in on the LJ4 paper curl debate, I began to get worried that I had bought
some sort of a lemon printer.  Not wanting to panic and do something rash
like return it to the store and demand a refund, I decided to conduct some
experiments and gather some data.

I printed test copies on the following printers:
   Printer type                  Paper Brand            Location
------------------------------------------------------------------
1) Apple LaserWriter Plus        NXP                    Work
2) Apple LaserWriter II          NXP                    Work
3) QMS-810                       NXP                    Work
4a) HP Laserjet 4 w/500feeder    Willcopy               Frys
4b) HP Laserjet 4                MCS                    Home
5) HP Laserjet IIIp              Willcopy               Frys
6) HP laserjet IIp               Willcopy               Frys

I used the following papers:
1) MCS Industries MCS Laser Bond 20lb
2) Noland paper NXP Copy Bond 20lb 10M white long grain
3) Willamette Willcopy Xerography DP 20lb

While I would like to have tried all paper combinations on all printers I
could get my hands on, this was not feasible since 3 of the tested
printers were being examined in a store (Fry's Electronics, Manhattan Bch).

I'll be conducting additional tests on the HP LJ4 using 4 paper types
soon, but here are the results for now...

The flattest lowest-curling printer/paper:
Apple LaserWriter II     with NXP 20lb

The most-curling printer/paper:
HP Laserjet IIp          with Willcopy 20lb

The ranking from least curling to most curling is as follows:
1) Apple LaserWriter II  NXP            least
4a) HP LJ4 w/500 feeder  Willcopy
2) Apple LaserWriter Plus NXP
3) QMS-810  NXP
4b) HP LJ4   MCS
5) HP IIIp   Willcopy
6) HP IIp    Willcopy                   most curling

The one issue I've not been able to get a handle on, is whether the HP LJ4
I was testing at Fry's Electronics was a valid test because of the fact that
it had an Optional 500 sheet feeder attached at its bottom.  This optional
feeder may have significantly changed the paper path from the standard
default path.  However, to counter that charge, When I was testing
a different LJ4 without the feeder, I ran paper through the paper cassette AND
the Multi-purpose tray on the side.  The MP tray side feeder is a less
extreme paper path than the paper cassette, and there was no change in 
paper curl with the MCS paper.

So in conclusion, the HP LJ4 curling is not the most egregious and can be
attenuated with some papers.  The HP IIp and IIIp were rather surprising
since I'd asumed they would have a less extreme paper path internally.  
Their high curling, and the IIp curling in particular was considerably more than
the LJ4's curl.  The IIp curled so much, the paper looked like a squashed U.
The Apple LaserWriter II (which is a rather long and low device) which still
curled enough to be visually seen is the printer I tend to use the most at work.

I suppose if you had been using an Apple LaserWriter II (or maybe an HP III)
and then switched to the LJ4, the curl would bother you a lot.  But in
comparison to other printers the LJ4 curl is not extreme, and if you pick
a workable paper (I know, lots of trial and error here) can be acceptable.
Maybe HP can put out their own brand of paper just for LJ4, or at least
provide a list of acceptable papers, rather than just the specs.

Hope this helps answer some questions.

Disclaimer: I work for neither HP, nor Apple, nor any paper companies, I'm
just a cold-war relic software engineer at Hughes Aircraft.

Warren R. Diamond
diamond@vulcan1.edsg.hac.com
Newsgroups: comp.periphs.printers