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Overview
They say that creativity is the mother of invention.
But sometimes raw unadulterated ignorance can foster
ideas just as grand. The idea for this project actually
came to me by a mix of creativity, and the common
ID10T Error. My good friend Mike owns a quickly
growing software development firm. He also has a
mountain of sensitive documents that seems to grow
as quickly as his business, piling up next to his
paper shredder. Being a small business owner he
prints all of his documents in house. Generally
speaking CEO’s and small business owners are
not always the most technical of people, so the
concept that a laser printer gets hot is not always
in the forefront of their minds. After attempting
to use a new special plastic based paper, the printer
feeding in sheet after sheet and not returning a
single sheet, he realized there might be a problem.
Upon closer inspection several pages of this special
paper had melted in the printer and completely destroyed
it. The ultimate “paper” jam.
About
the same time I decided to see if I could find
an automatic bulk paper shredder solution for
him. Sure enough I was able to find some options,
but they ranged from $3000 – $12000. Obviously
that wouldn’t do for the creative-minded
geek. So after some brainstorming and a lightning
strike or two, I had the idea to modify the remnants
of the laser printer to fill the role. As this
is going to be a volume based solution we needed
a robust and well built paper feed mechanism,
and a solid feed rate. Xerox has built their reputation
on the quality and performance of their printers.
Of course, with a reputation like that, what self
respecting modder wouldn’t jump at the opportunity
to apply a personal spin to it?
This
is really a relatively simple build. Most of the
time spent (and a good portion of the fun) is actually
tearing the printer apart so as to address any potential
heat sources and therefore any potential fire hazards
(we will still make sure you get to play with fire
later). The parts for this build are readily available
through several means. We will list the sources
and prices for all the parts below. |
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The
Printer:
This is ultimately the main part of this build.
In this build we will be using the XEROX 3450/B
this is a very capable laser printer at 25 Pages
Per Minute. The lower tray is capable of 500 sheets
of paper in both letter and legal sizes. The upper
tray is a multi-purpose tray capable of 100 sheets,
and is better with thicker materials. The printer
retails new for about $500.00 USD, but eBay and
refurbished units can range from $200 - $400. Now,
due to time and budget constraints we passed on
some of the “features” we wanted to
use from the printer. For instance… using
the toner cartridge to limit the number of pages
shredded and force you to buy a new “shredder”
cartridge, every 50K pages or so. Or perhaps a printer
bios upgrade to even print at all after 250,000
pages or so. |
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The
Motor:
For simplicity’s sake in this build we will
be replacing the existing main drive motor in the
printer. The reasoning behind this is the original
motor is a stepped motor and it would take longer,
and cost more in parts to build a controller for
it than it would to replace the motor outright with
an AC motor. This motor is actually scavenged from
an additional paper shredder that we will be using
in this build. The drive shaft of this motor is
a worm gear that matched the gearing where the original
one had been mounted. As the cost of this motor
is the price of the paper shredder, we will it at
$15.00. |
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The DC Power Supply:
One of the reasons for our choice of the
printer we choose (excluding the free price tag)
was the existing mechanics and the simplicity of
operation. The down side is that we will be stripping
all the existing electronics out of the unit, excluding
3 solenoids. We will need a DC based power supply
at about 5V to power these units. It just so happened
that I had a Samsung brick at 4.75V DC just lying
around. I really like the shape and size of this
transformer because it is thin enough to be hidden
inside the side cowls of the existing space. These
transformers are used in all sorts of electronic
components and are readily available on eBay for
$5.00.
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The
Paper Shredder (Qty - 2):
I tried many, many paper shredders out there before
I found one I was satisfied with. Believe it or
not, I chose a $15 shredder from Wal-Mart in the
end. The Aurora 5 Sheet Strip-Cut Paper Shredder
was the fastest paper shredder I could put my hands
on. It has only a strip type cutter in it, but that’s
good enough for what our needs. It also sports thermal
overload protection on the motor and will shut itself
down before “unsafe” conditions are
met. Not to mention when we are done with the shredder,
or it wares out we can return it back to Wal-Mart,
and there highly trained staff will most likely
take it back and refund our money. |
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The
solenoid controller:
The
solenoid controller is the key to this unit. This
is basically nothing more than a glorified LED Flasher,
but instead of LEDs, we will be driving the solenoids
in the printer with its output. The speed of the
flash (or drive-rate in this case) can be hard set
via resistor, capacitor or variable. After some
tinkering with a bread board, we chose a basic circuit
to drive the solenoids for a feed rate that doesn’t
overload the paper shredder. We built redundant
circuits to control the solenoids on the upper tray
and lower tray independently, thus allowing for
independent feed rates as well.
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Tools
that we used
( I.E. you may want to use as well )
One note on power tools: use them at your own risk. Be sure to read and
understand any and all documentation on the tools you use. No amount of
documentation can make up for experience, but there are many people with
serious eye injuries at the school of hard knocks. If you don't know what you
are doing, don't do it and find some one that can help.
Screwdrivers
Pliers
Soldering iron
Super Glue or Epoxy
Wire cutters
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