From: ard at p850ug1.demon.co.uk
Subject: Re: (OT) Laserjet III laser scanner module
To: cctalk at
classiccmp.org
Date: Tue, 29 Jun 2010 20:40:15 +0100
Replacing the laser assembly might be
"interesting", as will realigning
the optics. My back-of-an-envelope calculations suggest I need a 0.085mm
spot size to get to 300DPI:
There are of course various optical components in the sanner assemhly. A
pair of cylindrical lenses IIRC, various mirrosm and some kind of optical
uinit on the front of the laser diode.
300dpi = 300 dots per inch, or 1/300in per pixel
1/300 * 25.4mm/in = 0.0846667
Focusing that will be.... "fun", especially with a 20mW blue diode
laser... and I need to find a beam sensor that's sensitive to blue light.
Setting up a (CX engine) scanner from scratch was 'fun' too :-). It's an
IR laser so you can;'t see the beam. I was tracing it through the optical
bits with an IR remote control tester :-).
---snip---
Hi
Although, I've not tried this, it was mentioned that most digital cameras
have some sensitivity to IR ( even though they have filters to block most ).
One should be able to check things by using a digital camera to view with.
Dwight
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