Parts And Materials
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 also readily available.
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, 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 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.
The Motor: For simplicity's sake in this build we will replace 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.
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 downside is that we will be stripping all the existing electronics out of the unit, excluding three solenoids. We will need a DC based power supply at about 5V to power these units.